Showing papers by "University of Medicine and Dentistry of New Jersey published in 2001"

Polyamines in cell growth and cell death: molecular mechanisms and therapeutic applications.

Abstract: Polyamines are aliphatic cations with multiple functions and are essential for life. Cellular polyamine levels are regulated by multiple pathways such as synthesis from amino acid precursors, cellular uptake mechanisms that salvage polyamines from diet and intestinal microorganisms, as well as stepwise degradation and efflux. Investigations using polyamine biosynthetic inhibitors indicate that alterations in cellular polyamine levels modulate normal and cancer cell growth. Studies using transgenic mice overexpressing polyamine biosynthetic enzymes support a role of polyamines in carcinogenesis. Many, if not all, signal transduction pathways intersect with polyamine biosynthetic pathways and the regulation of intracellular polyamine levels. Direct binding of polyamines to DNA and their ability to modulate DNA-protein interactions appear to be important in the molecular mechanisms of polyamine action in cell proliferation. Consistent with the role of polyamines as facilitators of cell growth, several studies have shown their ability to protect cells from apoptosis. However, polyamines also have a role in facilitating cell death. The basis of these diverse cellular responses is currently not known. Cell death response might be partly mediated by the production of hydrogen peroxide during polyamine catabolism. In addition, the ability of polyamines to alter DNA-protein and protein-protein interactions might be disruptive to cellular functions, when abnormally high levels are accumulated due to defects in polyamine catabolic or efflux pathways. A large body of data indicates that polyamine pathway can be a molecular target for therapeutic intervention in several types cancers. Inhibitors of biosynthesis, polyamine analogues as well as oligonucleotide/polyamine analogue combinations are promising drug candidates for chemoprevention and/or treatment of cancer.

Emerging issues of connexin channels: biophysics fills the gap.

Abstract: This summary is a proposed synthesis of available information for the non-specialist. It does not incorporate all the published data, is inconsistent with some, and reflects the biases of the author. Connexin proteins have a common transmembrane topology, with four alpha-helical transmembrane domains, two extracellular loops, a cytoplasmic loop, and cytoplasmic N- and C-terminal domains. The sequences are most conserved in the transmembrane and extracellular domains, yet many of the key functional differences between connexins are determined by amino-acid differences in these largely conserved domains. Each extracellular loop contains three cysteines with invariant spacing (save one isoform) that are required for channel function. The junctional channel is composed of two end-to-end hemichannels, each of which is a hexamer of connexin subunits. Hemichannels formed by some connexin isoforms can function as well-behaved, single-membrane-spanning channels in plasma membrane. In junctional channels, the cysteines in the extracellular loops form intra-monomer disulfide bonds between the two loops, not intermonomer or inter-hemichannel bonds. The end-to-end homophilic binding between hemichannels is via non-covalent interactions. Mutagenesis studies suggest that the docking region contains beta structures, and may resemble to some degree the beta-barrel structure of porin channels. The two hemichannels that compose a junctional channel are rotationally staggered by approximately 30 degrees relative to each other so that the alpha-helices of each connexin monomer are axially aligned with the alpha-helices of two adjacent monomers in the apposed hemichannel. At present there is a published 3D map with 7.5 A resolution in the plane of the membrane, based on electron cryomicroscopy of 2D crystals of junctional channels formed by C-terminal truncated Cx43. The correspondence between the imaged transmembrane alpha-helices and the known transmembrane amino-acid sequences is a matter of debate. Each of the approximately 20 connexin isoforms produces channels with distinct unitary conductances, molecular permeabilities, and electrical and chemical gating sensitivities. The channels can be heteromeric, and subfamilies among connexins largely determine heteromeric specificity, similar to the specificities within the voltage-dependent potassium channel superfamily. The second extracellular loop contains the primary determinants of the specificity of hemichannel-hemichannel docking (analogous to the tetramerization domain of potassium channels). The 7.5 A map shows that each monomer exposes only two transmembrane alpha-helices to the pore lumen. However the conductance state of the imaged structure and the effects of the C-terminal truncation are unknown, so it is possible that other transmembrane domains contribute to the lumen in other functional states of the channel. In the transmembrane region, SCAM and mutagenesis data suggest that parts of the first three transmembrane alpha-helices are exposed to the lumen. Some of these data are contradictory, but may reflect conformational or isoform differences. There is reason to think that the first part of the N-terminal cytoplasmic domain can line the pore in some conformations. In the extracellular part of junctional channels, the N-terminal portion of the first extracellular loop is exposed to the lumen. The unitary conductances through connexin channels vary over an order of magnitude, from 15 pS to over 300 pS. There is a range of charge selectivities among atomic ions, from slightly anion selective to highly cation selective, which does not correlate with unitary conductance. There appear to be substantial ion-ion interactions within the pore, making the GHK model of assessing selectivities of limited value. Pores formed by different connexins have a range of limiting diameters as assessed by uncharged and charged probes, which also does not correlate with unitary conductance (i.e. some have high conductance but have a narrow limiting diameter, and vice versa). Channels formed by different connexins have different permeabilities to various cytoplasmic molecules. Where it has been assessed, the selectivity among cytoplasmic molecules is substantial and does not correlate in an obvious manner with the size selectivity data derived from fluorescent tracer studies, suggesting there are chemical specificities within the pore that enhance or reduce permeability to specific cytoplasmic molecules, functionally analogous to the ability of some porins to facilitate transport of specific substrates. For example, heteromeric channels with different stoichiometries or arrangements of isoforms can distinguish among second messengers. The differences in permeability to cytoplasmic molecules have biological consequences; in most cases one connexin cannot fully substitute for another. Voltage and chemical gating mechanisms largely operate within each hemichannel, though there is evidence for inter-hemichannel allosteric effects as well. There are at least two distinct gating mechanisms. One (Vj-gating) is a voltage-driven mechanism that governs rapid transitions between conducting states. Its voltage sensor involves charges in the first several positions of the cytoplasmic N-terminal domain and possibly in the N-terminal part of the first extracellular loop, which may both be exposed to the lumen of the pore in some states. The polarity of Vj-gating sensitivity is connexin-specific, closing with depolarization for some connexins and with hyperpolarization for others. The polarity can be reversed by point mutations at the second position. The lower conductance states induced by Vj-gating correspond to physical restrictions of the pore, and thus restricted or eliminated molecular permeation. Since the channels are not fully closed by Vj-gating, it can be seen as a way to eliminate molecular signaling while leaving electrical signaling operational. A second, independent gating mechanism mediates slow transitions (approximately 10-30 ms) into and out of non-conducting state(s). These transitions can occur in response to voltage ('loop gating'), chemical factors such as pH and lipophiles ('chemical gating'), and the docking of two hemichannels (sometimes called the 'docking gate'). These slow transitions may reflect a common structural change induced by these several effectors (electrical, chemical and homodimerization). Alternatively, they could reflect distinct gating processes responding to one or more of these effectors, that are indistinguishable at the single-channel level and have yet to be resolved mechanistically. The slow or loop gate closes with hyperpolarization. As a result, where Vj-gating closes with depolarization, individual hemichannels can close in response to both polarities of voltage (but only to a subconductance state for the Vj-gating polarity). Because of this, it is difficult to assign a macroscopic voltage sensitivity, or its modification due to mutagenesis, chemical modification or heteromeric interactions, to one or the other of these very distinct voltage-sensitive processes. This distinction can be made reliably only at the single-channel level. The Vj-gating voltage sensor and the loop-gating voltage sensor appear to be independent structures, since the Vj-gating voltage sensitivity can modified without effect on loop gating. For some connexins, certain modifications of the C-terminal domain seem to interfere with the operation of the Vj-gate while leaving loop gating unaffected. In some connexins, but not all, the chemical sensitivity to pH can involve interactions between regions of the C-terminal domain and cytoplasmic loop. Whether these regions exert their effects directly by physically blocking the pore, or by allosteric mechanisms (which may be more consistent with the relatively long time-course of closure) is not clear. For several connexins, truncation of the C-terminal domain eliminates the pH sensitivity, and co-expressing the domain with the truncated connexin restores the pH sensitivity. This has a functional resemblance to the particle-receptor mechanism for N-type inactivation of Shaker channels. What is being protonated is not clear, and may involve cytoplasmic factors, such as endogenous aminosulfonates. For other connexins, the action of pH does not involve the C-terminal domain and seems due to direct protonation of connexin. PKC phosphorylation of serine(s) in the C-terminal domain can affect the substate occupancy of at least one connexin. Phosphorylation of series in the C-terminal domain by MAP kinase appears to facilitate an interaction between it and an unknown receptor domain to eliminate coupling. This process has yet to be studied at the single-channel level. It also has a functional analogy to the particle-receptor model of channel inactivation. Both MAP kinase phosphorylation-induced and pH-induced inhibition can be mediated in truncated connexins by the corresponding free peptide. However, the relation between these two mechanisms are unexplored, as are specific mechanisms of direct endogenous regulation of connexin channel activity. (ABSTRACT TRUNCATED)

Factors Associated with Age at Natural Menopause in a Multiethnic Sample of Midlife Women

Abstract: An unprecedented number of women will experience menopause in the next decade. Although the timing of menopause affects long-term disease risk, little is known about factors that affect this timing. In the present 1995--1997 cross-sectional study, the Study of Women's Health Across the Nation, the relation of demographic and lifestyle factors to age at natural menopause was examined in seven US centers and five racial/ethnic groups. All characteristics were self-reported by women aged 40--55 years (n = 14,620). Cox proportional hazards models were used to estimate the probability of menopause by age. Overall, median age at natural menopause was 51.4 years, after adjustment for smoking, education, marital status, history of heart disease, parity, race/ethnicity, employment, and prior use of oral contraceptives. Current smoking, lower educational attainment, being separated/widowed/divorced, nonemployment, and history of heart disease were all independently associated with earlier natural menopause, while parity, prior use of oral contraceptives, and Japanese race/ethnicity were associated with later age at natural menopause. This sample is one of the largest and most diverse ever studied, and comprehensive statistical methods were used to assess factors associated with age at natural menopause. Thus, this study provides important insights into this determinant of long-term disease risk in women.

GABAergic mechanisms in epilepsy.

Abstract: gamma-Aminobutyric acid (GABA), the principal inhibitory neurotransmitter in the cerebral cortex, maintains the inhibitory tone that counterbalances neuronal excitation. When this balance is perturbed, seizures may ensue. GABA is formed within GABAergic axon terminals and released into the synapse, where it acts at one of two types of receptor: GABAA, which controls chloride entry into the cell, and GABAB, which increases potassium conductance, decreases calcium entry, and inhibits the presynaptic release of other transmitters. GABAA-receptor binding influences the early portion of the GABA-mediated inhibitory postsynaptic potential, whereas GABAB binding influences the late portion. GABA is rapidly removed by uptake into both glia and presynaptic nerve terminals and then catabolized by GABA transaminase. Experimental and clinical study evidence indicates that GABA has an important role in the mechanism and treatment of epilepsy: (a) Abnormalities of GABAergic function have been observed in genetic and acquired animal models of epilepsy; (b) Reductions of GABA-mediated inhibition, activity of glutamate decarboxylase, binding to GABAA and benzodiazepine sites, GABA in cerebrospinal fluid and brain tissue, and GABA detected during microdialysis studies have been reported in studies of human epileptic brain tissue; (c) GABA agonists suppress seizures, and GABA antagonists produce seizures; (d) Drugs that inhibit GABA synthesis cause seizures; and (e) Benzodiazepines and barbiturates work by enhancing GABA-mediated inhibition. Finally, drugs that increase synaptic GABA are potent anticonvulsants. Two recently developed antiepileptic drugs (AEDs), vigabatrin (VGB) and tiagabine (TGB), are examples of such agents. However, their mechanisms of action are quite different (VGB is an irreversible suicide inhibitor of GABA transaminase, whereas TGB blocks GABA reuptake into neurons and glia), which may account for observed differences in drug side-effect profile.

Telomere Length as an Indicator of Biological Aging: The Gender Effect and Relation With Pulse Pressure and Pulse Wave Velocity

Abstract: Chronological age is the primary determinant of stiffness of central arteries. Increased stiffness is an independent indicator of cardiovascular risk. The aim of this study was to determine whether...

Prevalence of autism in a United States population: the Brick Township, New Jersey, investigation

Abstract: Objective. This study determined the prevalence of autism for a defined community, Brick Township, New Jersey, using current diagnostic and epidemiologic methods. Methods. The target population was children who were 3 to 10 years of age in 1998, who were residents of Brick Township at any point during that year, and who had an autism spectrum disorder. Autism spectrum disorder was defined as autistic disorder, pervasive developmental disorder-not otherwise specified (PDD-NOS), and Asperger disorder. The study used 4 sources for active case finding: special education records, records from local clinicians providing diagnosis or treatment for developmental or behavioral disabilities, lists of children from community parent groups, and families who volunteered for participation in the study in response to media attention. The autism diagnosis was verified (or ruled out) for 71% of the children through clinical assessment. The assessment included medical and developmental history, physical and neurologic evaluation, assessment of intellectual and behavioral functioning, and administration of the Autism Diagnostic Observation Schedule—Generic. Results. The prevalence of all autism spectrum disorders combined was 6.7 cases per 1000 children. The prevalence for children whose condition met full diagnostic criteria for autistic disorder was 4.0 cases per 1000 children, and the prevalence for PDD-NOS and Asperger disorder was 2.7 cases per 1000 children. Characteristics of children with autism in this study were similar to those in previous studies of autism. Conclusions. The prevalence of autism in Brick Township seems to be higher than that in other studies, particularly studies conducted in the United States, but within the range of a few recent studies in smaller populations that used more thorough case-finding methods.

Long-term neuropsychological outcome after traumatic brain injury.

Abstract: Objective:To describe neuropsychological outcome 5 years after injury in persons with traumatic brain injury (TBI) who received inpatient medical rehabilitation. To determine the magnitude and pattern neuropsychological recovery from 1 year to 5 years after injury.Design:Longitudinal cohort study wi

Hepatocyte nuclear factor-1α is an essential regulator of bile acid and plasma cholesterol metabolism

Abstract: Maturity-onset diabetes of the young type 3 (MODY3) is caused by haploinsufficiency of hepatocyte nuclear factor-1α (encoded by TCF1). Tcf1−/− mice have type 2 diabetes, dwarfism, renal Fanconi syndrome, hepatic dysfunction and hypercholestrolemia. Here we explore the molecular basis for the hypercholesterolemia using oligonucleotide microchip expression analysis. We demonstrate that Tcf1−/− mice have a defect in bile acid transport, increased bile acid and liver cholesterol synthesis, and impaired HDL metabolism. Tcf1−/− liver has decreased expression of the basolateral membrane bile acid transporters Slc10a1, Slc21a3 and Slc21a5, leading to impaired portal bile acid uptake and elevated plasma bile acid concentrations. In intestine and kidneys, Tcf1−/− mice lack expression of the ileal bile acid transporter (Slc10a2), resulting in increased fecal and urinary bile acid excretion. The Tcf1 protein (also known as HNF-1α) also regulates transcription of the gene (Nr1h4) encoding the farnesoid X receptor-1 (Fxr-1), thereby leading to reduced expression of small heterodimer partner-1 (Shp-1) and repression of Cyp7a1, the rate-limiting enzyme in the classic bile acid biosynthesis pathway. In addition, hepatocyte bile acid storage protein is absent from Tcf1−/− mice. Increased plasma cholesterol of Tcf1−/− mice resides predominantly in large, buoyant, high-density lipoprotein (HDL) particles. This is most likely due to reduced activity of the HDL-catabolic enzyme hepatic lipase (Lipc) and increased expression of HDL-cholesterol esterifying enzyme lecithin:cholesterol acyl transferase (Lcat). Our studies demonstrate that Tcf1, in addition to being an important regulator of insulin secretion, is an essential transcriptional regulator of bile acid and HDL-cholesterol metabolism.

Cutting edge: IFN-inducible ELR- CXC chemokines display defensin-like antimicrobial activity.

Abstract: Recent reports highlighted the chemotactic activities of antimicrobial peptide defensins whose structure, charge, and size resemble chemokines. By assaying representative members of the four known families of chemokines we explored the obverse: whether some chemokines exert antimicrobial activity. In a radial diffusion assay, only recombinant monokine induced by IFN-gamma (MIG/CXCL9), IFN-gamma-inducible protein of 10 kDa (IP-10/CXCL10), and IFN-inducible T cell alpha chemoattractant (I-TAC/CXCL11), members of the IFN-gamma-inducible tripeptide motif Glu-Leu-Arg (ELR)(-) CXC chemokines, were antimicrobial against Escherichia coli and Listeria monocytogenes. Similar to human defensins, antimicrobial activities of the chemokines were inhibited by 50 and 100 mM NaCl. The concentration of MIG/CXCL9 and IP-10/CXCL10 released from IFN-gamma-stimulated PBMC in 24 h were, respectively, 35- and 28-fold higher than from unstimulated cells. Additionally, the amounts of chemokines released per monocyte suggest that, in tissues with mononuclear cell infiltration, IFN-gamma-inducible chemokines may reach concentrations necessary for microbicidal activity. IFN-gamma-inducible chemokines may directly inactivate microbes before attracting other host defense cells to the area of infection.

Immunopathology of secondary‐progressive multiple sclerosis

Abstract: Twenty-three plaques obtained at early autopsy from 2 patients with secondary-progressive multiple sclerosis were examined immunohistochemically for microglia/macrophages, and for immunoglobulins and components of activated complement. Most of the lesions examined in both cases exhibited evidence of low-grade active demyelination of an unusual type (frustrated phagocytosis) in periplaque white matter. This included linear groups of microglia engaging short segments of disrupted myelin that were associated with deposits of C3d, an opsonin formed during complement activation. Similar microglia/C3d/myelin profiles were not observed in newly forming lesions in cases of acute multiple sclerosis or other central white matter diseases. As C3d coupling is known to increase the immunogenicity of potential antigens enormously, present findings point to disrupted myelin close to plaques as a possible source of the putative multiple sclerosis antigen. Ongoing myelin destruction found in a high proportion of old, established plaques was surprising. It suggests that slowly expanding lesions (progressive plaques), in which ongoing myelin breakdown occurs in the absence of florid perivascular cell cuffing or other histological signs of acute inflammation, contribute to disease progression in cases of secondary-progressive multiple sclerosis.

Delay in presentation and evaluation for acute stroke : Stroke time registry for outcomes knowledge and epidemiology (S. T. R. O. K. E.)

Abstract: Background and Purpose—Early treatment is a critical determinant of successful intervention in acute stroke. The study was designed to find current patterns of stroke care by determining delays in time from onset of signs or symptoms to arrival at the emergency department and to initial evaluation by physicians and by identifying factors associated with these delays. Methods—Data were prospectively collected by nurses and physicians from patients, patients’ family members, and medical records from 10 hospitals of the Robert Wood Johnson Health System in New Jersey. Results—A total of 553 patients who presented with signs or symptoms of acute stroke were studied. Thirty-two percent of patients arrived at the emergency department within 1.5 hours of stroke onset. Forty-six percent of patients arrived within 3 hours and 61% within 6 hours. Delays in arrival time were significantly associated with sex, race, transportation mode, and history of cardiovascular disease. Patients arriving by ambulance were more l...

Evidence that neurones accumulating amyloid can undergo lysis to form amyloid plaques in Alzheimer's disease.

Abstract: Aims Amyloid has recently been shown to accumulate intracellularly in the brains of patients with Alzheimer's disease (AD), yet amyloid plaques are generally thought to arise from gradual extracellular amyloid deposition. We have investigated the possibility of a link between these two apparently conflicting observations. Methods and results Immunohistochemistry and digital image analysis was used to examine the detailed localization of beta-amyloid(42) (A beta 42), a major component of amyloid plaques, in the entorhinal cortex and hippocampus of AD brains. A beta 42 first selectively accumulates in the perikaryon of pyramidal cells as discrete, granules that appear to be cathepsin D-positive, suggesting that they may represent lysosomes or lysosome-derived structures. AD brain regions abundantly populated with pyramidal neurones exhibiting excessive A beta 42 accumulations also contained evidence of neuronal lysis. Lysis of these A beta 42-burdened neurones apparently resulted in a local, radial dispersion of their cytoplasmic contents, including A beta 42 and lysosomal enzymes, into the surrounding extracellular space. A nuclear remnant was found at the dense core of many amyloid plaques, strengthening the idea that each amyloid plaque represents the end product of a single neuronal cell lysis. The inverse relationship between the amyloid plaque density and pyramidal cell density in the AD brain regions also supports this possibility, as does the close correlation between plaque size and the size of local pyramidal cells. Conclusions Our findings suggest that excessive intracellular accumulation of A beta 42-positive material in pyramidal cells can result in cell lysis, and that cell lysis is an important source of amyloid plaques and neuronal loss in AD brains.

A randomized, controlled trial of methotrexate versus placebo in early diffuse scleroderma

Abstract: Objective. Early diffuse scleroderma (systemic sclerosis; SSc) has no proven treatment. This study was undertaken to examine the efficacy of methotrexate (MTX) in improving the skin and other disease parameters in early diffuse SSc. Methods. Seventy-one patients with diffuse SSc of <3 years' duration were enrolled in a multicenter, randomized, placebo-controlled, double-blind trial. Thirty-five patients were treated with MTX and 36 with placebo. Treatment was administered for 12 months. The primary outcome measures were skin score (as determined with 2 different indices) and physician global assessment. Results. At baseline, there were no statistically significant differences in skin scores, carbon monoxide diffusing capacity (DLco), physician global assessment, or other secondary outcome measurements between the 2 treatment groups. At study completion, results slightly favored the MTX group (mean SEM modified Rodnan skin score 21.4 +/- 2.8 in the MTX group versus 26.3 +/- 2.1 in the placebo group [P < 0.17]; UCLA skin score. 8.8 +/- 1.2 in the MTX group versus 11.0 +/- 0.9 in the placebo group [P < 0.15]; DLco in the MTX group 75.7 +/- 4.6 versus 61.8 +/- 3.4 in the placebo group [P < 0.2]). In addition, physician global assessment results favored MTX (P < 0.035), whereas patient global assessment did not differ significantly between groups. When between-group differences for changes in scores from baseline to 12 months were examined using intent-to-treat methodology, MTX appeared to have a favorable effect on skin scores (modified Rodnan score -4.3 in the MTX group versus 1.8 in the placebo group [P < 0.009]; UCLA score -1.2 in the MTX group versus 1.2 in the placebo group [P < 0.02]), but differences in the degree of change in the DLco and physician global assessment were not significant. For the UCLA skin score, these differences in results were not statistically significant after adjustment for baseline differences in sex distribution and steroid use. Dropout rates were similar in the 2 groups. Conclusion. Although results of this trial demonstrated a trend in favor of MTX versus placebo in the treatment of early diffuse SSc, the between-group differences were small and the power to rule out false-negative results was only 50%. Our findings do not provide evidence that MTX is significantly effective in the treatment of early diffuse SSc.

Human Cytomegalovirus with IE-2 (UL122) Deleted Fails To Express Early Lytic Genes

Abstract: Much evidence suggests that the major immediate-early (IE) transactivator of human cytomegalovirus (HCMV), IE-2, is likely to be critical for efficient viral replication; however, the lack of an IE-2 mutant HCMV has precluded an experimental test of this hypothesis. As an initial step toward characterizing an IE-2 mutant, we first cloned the HCMV Towne genome as a bacterial artificial chromosome (BAC) and analyzed the ability of transfected Towne-BAC DNA (T-BACwt) to produce plaques following introduction into permissive human fibroblasts. Like Towne viral DNA, transfected T-BACwt DNA was infectious in permissive cells, and the resulting virus stocks were indistinguishable from Towne virus. We then used homologous recombination in Escherichia coli to delete the majority of UL122, the open reading frame encoding the unique portion of IE-2, from T-BACwt. From this deleted BAC, a third BAC clone in which the deletion was repaired with wild-type UL122 was created. In numerous transfections of permissive human foreskin fibroblast cells with these three BAC DNA clones, the rescued BAC and T-BACwt consistently yielded plaques, while the UL122 mutant BAC never generated plaques, even after 4 weeks. Protein and mRNA of other IE genes were readily detected from transfected UL122 mutant BAC DNA; however, reverse transcription-PCR failed to detect mRNA expression from any of five early genes examined. The generalized failure of this mutant to express early genes is consistent with expectations from in vitro assays which have demonstrated that IE-2 transactivates most HCMV promoters. These experiments provide the first direct demonstration that IE-2 is required for successful HCMV infection and indicate that virus lacking IE-2 arrests early in the replication cycle.

Comparative efficacies of supportive and cognitive behavioral group therapies for young children who have been sexually abused and their nonoffending mothers.

Abstract: The differential efficacies of supportive and cognitive behavioral group therapy models designed for young children (ages 2 to 8) who have experienced sexual abuse and their nonoffending mothers were compared. Forty-four mothers and their respective children participated in either supportive or cognitive behavioral therapy groups with the group format being randomly determined. Repeated measures MANOVAs indicated that compared to mothers who participated in the support groups, the mothers who participated in cognitive behavioral groups reported greater reductions at posttest in (a) their intrusive thoughts and (b) their negative parental emotional reactions regarding the sexual abuse. The children treated with cognitive behavioral therapy demonstrated greater improvement in their knowledge regarding body safety skills at posttest than did the children who received supportive therapy.

Regulation of death receptor expression and TRAIL/Apo2L-induced apoptosis by NF-kappaB.

Abstract: TRAIL (tumour-necrosis factor-related apoptosis ligand or Apo2L) triggers apoptosis through engagement of the death receptors TRAIL-R1 (also known as DR4) and TRAIL-R2 (DR5). Here we show that the c-Rel subunit of the transcription factor NF-kappaB induces expression of TRAIL-R1 and TRAIL-R2; conversely, a transdominant mutant of the inhibitory protein IkappaBalpha or a transactivation-deficient mutant of c-Rel reduces expression of either death receptor. Whereas NF-kappaB promotes death receptor expression, cytokine-mediated activation of the RelA subunit of NF-kappaB also increases expression of the apoptosis inhibitor, Bcl-xL, and protects cells from TRAIL. Inhibition of NF-kappaB by blocking activation of the IkappaB kinase complex reduces Bcl-x L expression and sensitizes tumour cells to TRAIL-induced apoptosis. The ability to induce death receptors or Bcl-xL may explain the dual roles of NF-kappaB as a mediator or inhibitor of cell death during immune and stress responses.

Cutting Edge: NKG2D Receptors Induced by IL-15 Costimulate CD28-Negative Effector CTL in the Tissue Microenvironment

Abstract: Unlike primary T cells in lymph nodes, effector CD8(+) CTL in tissues do not express the costimulatory receptor CD28. We report that NKG2D, the receptor for stress-induced MICA and MICB molecules expressed in the intestine, serves as a potent costimulatory receptor for CTL freshly isolated from the human intestinal epithelium. Expression and function of NKG2D are selectively up-regulated by the cytokine IL-15, which is released by the inflamed intestinal epithelium. These findings identify a novel CTL costimulatory pathway regulated by IL-15 and suggest that tissues can fine-tune the activation of effector T cells based on the presence or absence of stress and inflammation. Uncontrolled secretion of IL-15 could lead to excessive induction of NKG2D and thus contribute to the development of autoimmune disease by facilitating the activation of autoreactive T cells.

Brain structures and neurotransmitters regulating aggression in cats: Implications for human aggression.

Abstract: 1. Violence and aggression are major public health problems. 2. The authors have used techniques of electrical brain stimulation, anatomical-immunohistochemical techniques, and behavioral pharmacology to investigate the neural systems and circuits underlying aggressive behavior in the cat. 3. The medial hypothalamus and midbrain periaqueductal gray are the most important structures mediating defensive rage behavior, and the perifornical lateral hypothalamus clearly mediates predatory attack behavior. The hippocampus, amygdala, bed nucleus of the stria terminalis, septal area, cingulate gyrus, and prefrontal cortex project to these structures directly or indirectly and thus can modulate the intensity of attack and rage. 4. Evidence suggests that several neurotransmitters facilitate defensive rage within the PAG and medial hypothalamus, including glutamate, Substance P, and cholecystokinin, and that opioid peptides suppress it; these effects usually depend on the subtype of receptor that is activated. 5. A key recent discovery was a GABAergic projection that may underlie the often-observed reciprocally inhibitory relationship between these two forms of aggression. 6. Recently, Substance P has come under scrutiny as a possible key neurotransmitter involved in defensive rage, and the mechanism by which it plays a role in aggression and rage is under investigation. 7. It is hoped that this line of research will provide a better understanding of the neural mechanisms and substrates regulating aggression and rage and thus establish a rational basis for treatment of disorders associated with these forms of aggression.

The efficacy and tolerability of vardenafil, a new, oral, selective phosphodiesterase type 5 inhibitor, in patients with erectile dysfunction: the first at-home clinical trial.

Abstract: Vardenafil, a novel selective phosphodiesterase type 5 inhibitor, was evaluated in its first large-scale at-home trial. A total of 601 men with mild to severe erectile dysfunction (ED) were enrolled in this multi-centre, randomized, double-blind, placebo-controlled trial of 12 weeks of treatment with either placebo or 5, 10 and 20 mg of vardenafil. Primary endpoints were Q3 (vaginal penetration) and Q4 (maintenance of erection) of the International Index of Erectile Function (IIEF). In the intent-to-treat population (n=580), the changes from baseline for 5, 10 and 20 mg vardenafil (1.2, 1.3 and 1.5, respectively) were all improved (P<0.001) over placebo (0.2) for Q3 and were similarly improved for Q4 (1.4, 1.5 and 1.7) compared to placebo (0.5) (P<0.001). All vardenafil doses improved all IIEF domains compared to placebo (P<0.001). The percentage of successful intercourses was between 71 and 75% for the three vardenafil doses. For the 20 mg dose, 80% of the patients experienced improved erections (GAQ) compared to 30% for placebo. Most frequent treatment-emergent adverse events were headache (7-15%), flushing (10-11%) and up to 7% for dyspepsia or rhinitis. Vardenafil treatment resulted in a high efficacy and low adverse-event profile in a population with mixed ED etiologies.

Functional magnetic resonance imaging of working memory impairment after traumatic brain injury

Abstract: OBJECTIVES—To examine patterns of brain activation while performing a working memory task in persons with moderate to severe traumatic brain injury (TBI) and healthy controls. It is well established that working memory is an area of cognition that is especially vulnerable to disruption after TBI. Although much has been learned about the system of cerebral representation of working memory in healthy people, little is known about how this system is disrupted by TBI. METHODS—Functional magnetic resonance imaging (fMRI) was used to assess brain activation during a working memory task (a modified version of the paced auditory serial addition test) in nine patients with TBI and seven healthy controls. RESULTS—Patients with TBI were able to perform the task, but made significantly more errors than healthy controls. Cerebral activation in both groups was found in similar regions of the frontal, parietal, and temporal lobes, and resembled patterns of activation found in previous neuroimaging studies of working memory in healthy persons. However, compared with the healthy controls, the TBI group displayed a pattern of cerebral activation that was more regionally dispersed and more lateralised to the right hemisphere. Differences in lateralisation were particularly evident in the frontal lobes. CONCLUSIONS—Impairment of working memory in TBI seems to be associated with alterations in functional cerebral activity.

Constraints on reinitiation of translation in mammals.

Abstract: The efficiency of reinitiation in mammalian translation systems depends in part on the size and arrangement of upstream open reading frames (upORFs). The gradual decrease in reinitiation as an upORF is lengthened, confirmed here using a variety of sequences, might reflect time-dependent loss of protein factors required for reinitiation. Consistent with the idea that the duration of elongation is what matters, reinitiation was nearly abolished when a pseudoknot that causes a pause in elongation was inserted into a short upORF. Control experiments showed that this transient pause in elongation had little effect on the final protein yield when the pseudoknot was moved from the upORF into the main ORF. Thus, the deleterious effect of slowing elongation is limited to the reinitiation mode. Another aspect of reinitiation investigated here is whether post-termination ribosomes can scan backwards to initiate at AUG codons positioned upstream from the terminator codon. Earlier studies that raised this possibility may have been complicated by the occurrence of leaky scanning along with reinitiation. Re-examination of the question, using constructs that preclude leaky scanning, shows barely detectable reinitiation from an AUG codon positioned 4 nt upstream from the terminator codon and no detectable reinitiation from an AUG codon positioned farther upstream. These experiments carried out with synthetic transcripts help to define the circumstances under which reinitiation may be expected to occur in the growing number of natural mRNAs that deviate from the simple first AUG rule.

Functional heterogeneity in liver and lung macrophages

Abstract: Although initially considered merely "scavenger cells" that participate in immunologic responses only after B and T lymphocytes have performed their biological tasks, more recent evidence suggests that macrophages play a key role in host defense as well as in the maintenance of normal tissue structure and function. For macrophages to perform their biological functions, they must be activated. This involves up-regulation of an array of signaling pathways resulting in altered gene expression and increased biochemical and functional activity. Macrophages have been identified in almost all tissues of the body. However, the basal activity of these cells, as well as their ability to respond to inflammatory mediators, varies considerably with their location. In addition, even within a particular tissue, there is evidence of macrophage heterogeneity. The largest populations of macrophages in the body are located in the liver and lung. Because of the unique attributes of these tissues, hepatic and pulmonary macrophages play essential roles not only in nonspecific host defense but also in the homeostatic responses of these tissues. In this review, the functional and biochemical activities of macrophages localized in the liver and lungs are compared. Evidence suggests that these represent distinct cell populations with unique functions and responsiveness to inflammatory agents.

Physiological and Genomic Consequences of Intermittent Hypoxia Invited Review: Physiological and pathophysiological responses to intermittent hypoxia

Abstract: Neubauer, Judith A. Invited Review: Physiological and pathophysiological responses to intermittent hypoxia. J Appl Physiol 90: 1593–1599, 2001.—This mini-review summarizes the physiological adaptations to and pathophysiological consequences of intermittent hypoxia with special emphasis given to the pathophysiology associated with obstructive sleep apnea. Intermittent hypoxia is an effective stimulus for evoking the respiratory, cardiovascular, and metabolic adaptations normally associated with continuous chronic hypoxia. These adaptations are thought by some to be beneficial in that they may provide protection against disease as well as improve exercise performance in athletes. The long-term consequences of chronic intermittent hypoxia may have detrimental effects, including hypertension, cerebral and coronary vascular problems, developmental and neurocognitive deficits, and neurodegeneration due to the cumulative effects of persistent bouts of hypoxia. Emphasis is placed on reviewing the available data on intermittent hypoxia, making extensions from applicable information from acute and chronic hypoxia studies, and pointing out major gaps in information linking the genomic and cellular responses to intermittent hypoxia with physiological or pathophysiological responses.

Placental Abruption and Perinatal Mortality in the United States

Abstract: Placental abruption is an uncommon obstetric complication associated with high perinatal mortality rates. The authors explored the associations of abruption with fetal growth restriction, preterm delivery, and perinatal survival. The study was based on 7,508,655 singleton births delivered in 1995 and 1996 in the United States. Abruption was recorded in 6.5 per 1,000 births. Perinatal mortality was 119 per 1,000 births with abruption compared with 8.2 per 1,000 among all other births. The high mortality with abruption was due, in part, to its strong association with preterm delivery; 55% of the excess perinatal deaths with abruption were due to early delivery. Furthermore, babies in the lowest centile of weight ( or =90%) birth weight centiles. This relative risk progressively declined with higher birth weight centiles. After controlling for fetal growth restriction and early delivery, the high risk of perinatal death associated with abruption persisted. Even babies born at 40 weeks of gestation and birth weight of 3,500-3,999 g (where mortality was lowest) had a 25-fold higher mortality with abruption. The link between fetal growth restriction and abruption suggests that the origins of abruption lie at least in midpregnancy and perhaps even earlier.

Invited review: Physiological and pathophysiological responses to intermittent hypoxia.

Abstract: This mini-review summarizes the physiological adaptations to and pathophysiological consequences of intermittent hypoxia with special emphasis given to the pathophysiology associated with obstructive sleep apnea. Intermittent hypoxia is an effective stimulus for evoking the respiratory, cardiovascular, and metabolic adaptations normally associated with continuous chronic hypoxia. These adaptations are thought by some to be beneficial in that they may provide protection against disease as well as improve exercise performance in athletes. The long-term consequences of chronic intermittent hypoxia may have detrimental effects, including hypertension, cerebral and coronary vascular problems, developmental and neurocognitive deficits, and neurodegeneration due to the cumulative effects of persistent bouts of hypoxia. Emphasis is placed on reviewing the available data on intermittent hypoxia, making extensions from applicable information from acute and chronic hypoxia studies, and pointing out major gaps in information linking the genomic and cellular responses to intermittent hypoxia with physiological or pathophysiological responses.

Parallel cortical networks for volitional control of swallowing in humans.

Abstract: A number of studies have demonstrated the involvement of parallel networks in the control of voluntary sequential motor procedures. We sought to determine whether a parallel network organization may be found for complex, sequentially based motor systems that are the product of both voluntary and automatic control processes. Specifically, we sought to determine whether the cortical organizational scheme for voluntary repetitive swallowing in adult humans is characterized by a hierarchical dual-projection model or by modules organized into parallel systems. We utilized functional magnetic resonance imaging (fMRI) to investigate cortical function during normal swallowing tasks in eight healthy human adults. Subjects performed both dry (saliva) and bolus (3 ml/bolus of water) swallows. Activation during swallowing tasks localized to sensorimotor areas (M1, S1, and SMA), S2, premotor cortex, posterior parietal cortex, cingulate gyrus, inferior frontal gyrus, the cerebellum, the insular cortex, auditory cortex, corpus callosum, and the basal ganglia and thalamus. Principal components analysis (PCA) of these regions revealed five functional clusters or modules: (1) sensorimotor areas and cingulate gyrus; (2) inferior frontal gyrus, S2, corpus callosum, basal ganglia and thalamus; (3) premotor cortex and posterior parietal cortex; (4) cerebellum; and (5) insula. Analysis of the functional relationship between these areas demonstrated two parallel loops defined by connections to either the cerebellum or insula and connected through the sensorimotor-cingulate module. Path analysis was performed to test the hypothesis of modules organized into parallel loops versus a hierarchical dual-projection model consisting of two separate, singular hierarchical serial pathways from the sensorimotor cortex or insula to the thalamus. These results support the model of modules organized into parallel loops (P=0.8), but not the hierarchical dual-projection model (P<0.0001). Organization of the control of voluntary repetitive swallowing into two parallel systems may confer the ability to effectively coordinate and integrate this highly complex sequentially based motor behavior.

Genomic structure, chromosomal localization and expression profile of a novel melanoma differentiation associated (mda-7) gene with cancer specific growth suppressing and apoptosis inducing properties.

Abstract: Abnormalities in cellular differentiation are frequent occurrences in human cancers. Treatment of human melanoma cells with recombinant fibroblast interferon (IFN-β) and the protein kinase C activator mezerein (MEZ) results in an irreversible loss in growth potential, suppression of tumorigenic properties and induction of terminal cell differentiation. Subtraction hybridization identified melanoma differentiation associated gene-7 (mda-7), as a gene induced during these physiological changes in human melanoma cells. Ectopic expression of mda-7 by means of a replication defective adenovirus results in growth suppression and induction of apoptosis in a broad spectrum of additional cancers, including melanoma, glioblastoma multiforme, osteosarcoma and carcinomas of the breast, cervix, colon, lung, nasopharynx and prostate. In contrast, no apparent harmful effects occur when mda-7 is expressed in normal epithelial or fibroblast cells. Human clones of mda-7 were isolated and its organization resolved in terms of intron/exon structure and chromosomal localization. Hu-mda-7 encompasses seven exons and six introns and encodes a protein with a predicted size of 23.8 kDa, consisting of 206 amino acids. Hu-mda-7 mRNA is stably expressed in the thymus, spleen and peripheral blood leukocytes. De novo mda-7 mRNA expression is also detected in human melanocytes and expression is inducible in cells of melanocyte/melanoma lineage and in certain normal and cancer cell types following treatment with a combination of IFN-β plus MEZ. Mda-7 expression is also induced during megakaryocyte differentiation induced in human hematopoietic cells by treatment with TPA (12-O-tetradecanoyl phorbol-13-acetate). In contrast, de novo expression of mda-7 is not detected nor is it inducible by IFN-β+MEZ in a spectrum of additional normal and cancer cells. No correlation was observed between induction of mda-7 mRNA expression and growth suppression following treatment with IFN-β+MEZ and induction of endogenous mda-7 mRNA by combination treatment did not result in significant intracellular MDA-7 protein. Radiation hybrid mapping assigned the mda-7 gene to human chromosome 1q, at 1q 32.2 to 1q41, an area containing a cluster of genes associated with the IL-10 family of cytokines. Mda-7 represents a differentiation, growth and apoptosis associated gene with potential utility for the gene-based therapy of diverse human cancers.