Showing papers by "University of Medicine and Dentistry of New Jersey published in 2002"

Histone methyltransferase activity associated with a human multiprotein complex containing the Enhancer of Zeste protein

Abstract: Enhancer of Zeste [E(z)] is a Polycomb-group transcriptional repressor and one of the founding members of the family of SET domain-containing proteins. Several SET-domain proteins possess intrinsic histone methyltransferase (HMT) activity. However, recombinant E(z) protein was found to be inactive in a HMT assay. Here we report the isolation of a multiprotein E(z) complex that contains extra sex combs, suppressor of zeste-12 [Su(z)12], and the histone binding proteins RbAp46/RbAp48. This complex, which we termed Polycomb repressive complex (PRC) 2, possesses HMT activity with specificity for Lys 9 (K9) and Lys 27 (K27) of histone H3. The HMT activity of PRC2 is dependent on an intact SET domain in the E(z) protein. We hypothesize that transcriptional repression by the E(z) protein involves methylation-dependent recruitment of PRC1. The presence of Su(z)12, a strong suppressor of position effect variegation, in PRC2 suggests that PRC2 may play a widespread role in heterochromatin-mediated silencing.

Drusen proteome analysis: An approach to the etiology of age-related macular degeneration

Abstract: Drusen are extracellular deposits that accumulate below the retinal pigment epithelium on Bruch's membrane and are risk factors for developing age-related macular degeneration (AMD). The progression of AMD might be slowed or halted if the formation of drusen could be modulated. To work toward a molecular understanding of drusen formation, we have developed a method for isolating microgram quantities of drusen and Bruch's membrane for proteome analysis. Liquid chromatography tandem MS analyses of drusen preparations from 18 normal donors and five AMD donors identified 129 proteins. Immunocytochemical studies have thus far localized ≈16% of these proteins in drusen. Tissue metalloproteinase inhibitor 3, clusterin, vitronectin, and serum albumin were the most common proteins observed in normal donor drusen whereas crystallin was detected more frequently in AMD donor drusen. Up to 65% of the proteins identified were found in drusen from both AMD and normal donors. However, oxidative protein modifications were also observed, including apparent crosslinked species of tissue metalloproteinase inhibitor 3 and vitronectin, and carboxyethyl pyrrole protein adducts. Carboxyethyl pyrrole adducts are uniquely generated from the oxidation of docosahexaenoate-containing lipids. By Western analysis they were found to be more abundant in AMD than in normal Bruch's membrane and were found associated with drusen proteins. Carboxymethyl lysine, another oxidative modification, was also detected in drusen. These data strongly support the hypothesis that oxidative injury contributes to the pathogenesis of AMD and suggest that oxidative protein modifications may have a critical role in drusen formation.

The International Index of Erectile Function (IIEF): a state-of-the-science review.

Abstract: The International Index of Erectile Function (IIEF) is a widely used, multi-dimensional self-report instrument for the evaluation of male sexual function. It is has been recommended as a primary endpoint for clinical trials of erectile dysfunction (ED) and for diagnostic evaluation of ED severity. The IIEF was developed in conjunction with the clinical trial program for sildenafil, and has since been adopted as the 'gold standard' measure for efficacy assessment in clinical trials of ED. It has been linguistically validated in 32 languages and used as a primary endpoint in more than 50 clinical trials. This review summarizes early stages in the psychometric validation of the instrument, its subsequent adoption in randomized clinical trials with sildenafil and other ED therapies, and its use in classifying ED severity and prevalence. The IIEF meets psychometric criteria for test reliability and validity, has a high degree of sensitivity and specificity, and correlates well with other measures of treatment outcome. It has demonstrated consistent and robust treatment responsiveness in studies in USA, Europe and Asia, as well as in a wide range of etiological subgroups. Although only one direct comparator trial has been performed to date, the IIEF is also sensitive to therapeutic effects with treatment agents other than sildenafil. A severity classification for ED has recently been developed, in addition to a brief screening version of the instrument. This review includes the strengths as well as limitations of the IIEF, along with some potential areas for future research.

Virtual Reality–Augmented Rehabilitation for Patients Following Stroke

Abstract: Background and Purpose . Recent evidence indicates that intensive massed practice may be necessary to modify neural organization and effect recovery of motor skills in patients following stroke. Virtual reality (VR) technology has the capability of creating an interactive, motivating environment in which practice intensity and feedback can be manipulated to create individualized treatments to retrain movement. Case Description . Three patients (ML, LE, and DK), who were in the chronic phase following stroke, participated in a 2-week training program (3½ hours a day) including dexterity tasks on real objects and VR exercises. The VR simulations were targeted for range of motion, movement speed, fractionation, and force production. Outcomes . ML's function was the most impaired at the beginning of the intervention, but showed improvement in the thumb and fingers in range of motion and speed of movement. LE improved in fractionation and range of motion of his thumb and fingers. DK made the greatest gains, showing improvement in range of motion and strength of the thumb, velocity of the thumb and fingers, and fractionation. Two of the 3 patients improved on the Jebsen Test of Hand Function. Discussion . The outcomes suggest that VR may be useful to augment rehabilitation of the upper limb in patients in the chronic phase following stroke.

Set9, a novel histone H3 methyltransferase that facilitates transcription by precluding histone tail modifications required for heterochromatin formation

Abstract: A novel histone methyltransferase, termed Set9, was isolated from human cells. Set9 contains a SET domain, but lacks the pre- and post-SET domains. Set9 methylates specifically lysine 4 (K4) of histone H3 (H3-K4) and potentiates transcription activation. The histone H3 tail interacts specifically with the histone deacetylase NuRD complex. Methylation of histone H3-K4 by Set9 precludes the association of NuRD with the H3 tail. Moreover, methylation of H3-K4 impairs Suv39h1-mediated methylation at K9 of H3 (H3-K9). The interplay between the Set9 and Suv39h1 histone methyltransferases is specific, as the methylation of H3-K9 by the histone methyltransferase G9a was not affected by Set9 methylation of H3-K4. Our studies suggest that Set9-mediated methylation of H3-K4 functions in transcription activation by competing with histone deacetylases and by precluding H3-K9 methylation by Suv39h1. Our results suggest that the methylation of histone tails can have distinct effects on transcription, depending on its chromosomal location, the combination of posttranslational modifications, and the enzyme (or protein complex) involved in the particular modification.

Cyclo-Oxygenase 2 Function Is Essential for Bone Fracture Healing

Abstract: Despite the molecular and histological similarities between fetal bone development and fracture healing, inflammation is an early phase of fracture healing that does not occur during development. Cyclo-oxygenase 2 (COX-2) is induced at inflammation sites and produces proinflammatory prostaglandins. To determine if COX-2 functions in fracture healing, rats were treated with COX-2-selective nonsteroidal anti-inflammatory drugs (NSAIDs) to stop COX-2-dependent prostaglandin production. Radiographic, histological, and mechanical testing determined that fracture healing failed in rats treated with COX-2-selective NSAIDs (celecoxib and rofecoxib). Normal fracture healing also failed in mice homozygous for a null mutation in the COX-2 gene. This shows that COX-2 activity is necessary for normal fracture healing and confirms that the effects of COX-2-selective NSAIDs on fracture healing is caused by inhibition of COX-2 activity and not from a drug side effect. Histological observations suggest that COX-2 is required for normal endochondral ossification during fracture healing. Because mice lacking Cox2 form normal skeletons, our observations indicate that fetal bone development and fracture healing are different and that COX-2 function is specifically essential for fracture healing.

Telomere Length in the Newborn

Abstract: Telomere length is similar in different organs of the human fetus but variable among fetuses. During extrauterine life telomere length is highly variable among individuals and longer in women than men. In the present work we addressed the following questions: 1) Are there sex-related differences in telomere length at birth? 2) Is there synchrony (i.e. correlation in length) of telomeres in tissues within the newborn? 3) Is the variability in telomere length among newborns as large as that in adults? We studied normal male and female newborns who donated DNA samples from three sources: white blood cells, umbilical artery, and foreskin. Telomere length was measured by the mean length of the terminal restriction fragments (TRF). TRF length was not different between male and female newborns. It was highly synchronized among the DNA samples from white blood cells, umbilical artery and skin within individual donors but exhibited a high variability among donors. We conclude that there is no evidence for the effect of sex on telomere length at birth, suggesting that longer telomeres in women than men arise from a slower rate of telomeric attrition in women. The variability in telomere length among newborns and synchrony in telomere length within organs of the newborn are consistent with the concept that variations in telomere length among adults are in large part attributed to determinants (genetic and environmental) that start exerting their effect in utero.

Phase I Trial of Intravenous Administration of PV701, an Oncolytic Virus, in Patients With Advanced Solid Cancers

Abstract: PURPOSE: PV701, a replication-competent strain of Newcastle disease virus, causes regression of tumor xenografts after intravenous administration. This phase I study was designed to define the maximum-tolerated dose (MTD) and safety of single and multiple intravenous doses of PV701 as a single agent in patients with cancer. PATIENTS AND METHODS: Seventy-nine patients with advanced solid cancers that were unresponsive to standard therapy were enrolled. Four PV701 intravenous dosing regimens were evaluated: (1) single dose: one dose every 28 days; (2) repeat dose: three doses in 1 week every 28 days; (3) desensitizing: one lower dose followed by two higher doses in 1 week every 28 days; and (4) two week: one lower dose followed by five higher doses over 2 weeks every 21 days. RESULTS: A 100-fold dose intensification was achieved over 195 cycles. A first-dose MTD of 12 × 109 plaque-forming units (PFU)/m2 was established for outpatient dosing. After an initial dose of 12 × 109 PFU/m2, patients tolerated an MT...

DNA Nanoparticles and Development of DNA Delivery Vehicles for Gene Therapy

Abstract: DNA transport through the cell membrane is an essential requirement for gene therapy, which utilizes oligonucleotides and plasmid DNA. However, membrane transport of DNA is an inefficient process, and the mechanism(s) by which this process occurs is not clear. Although viral vectors are effective in gene therapy, the immune response elicited by viral proteins poses a major problem. Therefore, several laboratories are involved in the development of nonviral DNA delivery vehicles. These vehicles include polyamines, polycationic lipids, and neutral polymers, capable of condensing DNA to nanoparticles with radii of 20−100 nm. Although the structural and energetic forces involved in DNA condensation have been studied by physical biochemists for the past 25 years, this area has experienced a resurgence of interest in recent years because of the influx of biotechnologists involved in developing gene therapy protocols to combat a variety of human diseases. Despite an intense effort to study the mechanism(s) of DN...

Cooperativity of Nkx3.1 and Pten loss of function in a mouse model of prostate carcinogenesis

Abstract: Mouse models have provided significant insights into the molecular mechanisms of tumor suppressor gene function. Here we use mouse models of prostate carcinogenesis to demonstrate that the Nkx3.1 homeobox gene undergoes epigenetic inactivation through loss of protein expression. Loss of function of Nkx3.1 in mice cooperates with loss of function of the Pten tumor suppressor gene in cancer progression. This cooperativity results in the synergistic activation of Akt (protein kinase B), a key modulator of cell growth and survival. Our findings underscore the significance of interactions between tissue-specific regulators such as Nkx3.1 and broad-spectrum tumor suppressors such as Pten in contributing to the distinct phenotypes of different cancers.

Matrix assembly, regulation, and survival functions of laminin and its receptors in embryonic stem cell differentiation

Abstract: Laminin-1 is essential for early embryonic basement membrane assembly and differentiation. Several steps can be distinguished, i.e., the expression of laminin and companion matrix components, their accumulation on the cell surface and assembly into basement membrane between endoderm and inner cell mass, and the ensuing differentiation of epiblast. In this study, we used differentiating embryoid bodies derived from mouse embryonic stem cells null for γ1-laminin, β1-integrin and α/β-dystroglycan to dissect the contributions of laminin domains and interacting receptors to this process. We found that (a) laminin enables β1-integrin–null embryoid bodies to assemble basement membrane and achieve epiblast with β1-integrin enabling expression of the laminin α1 subunit; (b) basement membrane assembly and differentiation require laminin polymerization in conjunction with cell anchorage, the latter critically dependent upon a heparin-binding locus within LG module-4; (c) dystroglycan is not uniquely required for basement membrane assembly or initial differentiation; (d) dystroglycan and integrin cooperate to sustain survival of the epiblast and regulate laminin expression; and (e) laminin, acting via β1-integrin through LG1–3 and requiring polymerization, can regulate dystroglycan expression.

Hip muscle imbalance and low back pain in athletes: influence of core strengthening.

Abstract: NADLER, S. F., G. A. MALANGA, L. A. BARTOLI, J. H. FEINBERG, M. PRYBICIEN, and M. DEPRINCE. Hip muscle imbalance and low back pain in athletes: influence of core strengthening. Med. Sci. Sports Exerc., Vol. 34, No. 1, 2002, pp. 9‐16. Purpose: The influence of a core-strengthening program on low back pain (LBP) occurrence and hip strength differences were studied in NCAA Division I collegiate athletes. Methods: In 1998, 1999, and 2000, hip strength was measured during preparticipation physical examinations and occurrence of LBP was monitored throughout the year. Following the 1999‐2000 preparticipation physicals, all athletes began participation in a structured core-strengthening program, which emphasized abdominal, paraspinal, and hip extensor strengthening. Incidence of LBP and the relationship with hip muscle imbalance were compared between consecutive academic years. Results: After incorporation of core strengthening, there was no statistically significant change in LBP occurrence. Side-to-side extensor strength between athletes participating in both the 1998‐1999 and 1999‐2000 physicals were no different. After core strengthening, the right hip extensor was, on average, stronger than that of the left hip extensor (P ! 0.0001). More specific gender differences were noted after core strengthening. Using logistic regression, female athletes with weaker left hip abductors had a more significant probability of requiring treatment for LBP (P ! 0.009) Conclusion: The impact of core strengthening on collegiate athletes has not been previously examined. These results indicated no significant advantage of core strengthening in reducing LBP occurrence, though this may be more a reflection of the small numbers of subjects who actually required treatment. The core program, however, seems to have had a role in modifying hip extensor strength balance. The association between hip strength and future LBP occurrence, observed only in females, may indicate the need for more gender-specific core programs. The need for a larger scale study to examine

Measuring disease activity and functional status in patients with scleroderma and Raynaud's phenomenon

Abstract: Objective To document disease activity and functional status in patients with scleroderma (systemic sclerosis [SSc]) and Raynaud's phenomenon (RP) and to determine the sensitivity to change, reliability, ease of use, and validity of various outcome measures in these patients. Methods Patients with SSc and moderate-to-severe RP participating in a multicenter RP treatment trial completed daily diaries documenting the frequency and duration of RP attacks and recorded a daily Raynaud's Condition Score (RCS). Mean scores for the 2-week periods prior to baseline (week 0), end of trial (week 6), and posttrial followup (week 12) were calculated. At weeks 0, 6, and 12, physicians completed 3 global assessment scales and performed clinical assessments of digital ulcers and infarcts; patients completed the Health Assessment Questionnaire (HAQ), the Arthritis Impact Measurement Scales 2 (AIMS2) mood and tension subscales, 5 specific SSc/RP-related visual analog scales (VAS), and 3 other VAS global assessments. We used these measures to document baseline disease activity and to assess their construct validity, sensitivity to change, and reliability in trial data. Results Two hundred eighty-one patients (248 women, 33 men; mean age 50.4 years [range 18–82 years]) from 14 centers participated. Forty-eight percent had limited cutaneous SSc; 52% had diffuse cutaneous SSc. Fifty-nine patients (21%) had digital ulcers at baseline. Patients had 3.89 ± 2.33 (mean ± SD) daily RP attacks (range 0.8–14.6), with a duration of 82.1 ± 91.6 minutes/attack. RCS for RP activity (possible range 0–10) was 4.30 ± 1.92. HAQ scores (0–3 scale) indicated substantial disability at baseline (total disability 0.86, pain 1.19), especially among the subscales pertaining to hand function (grip, eating, dressing). AIMS2 mood and tension scores were fairly high, as were many of the VAS scores. Patients with digital ulcers had worse RCS, pain, HAQ disability (overall, grip, eating, and dressing), physician's global assessment, and tension, but no significant difference in the frequency of RP, duration of RP, patient's global assessment, or mood, compared with patients without digital ulcers. VAS scores for digital ulcers as rated by the patients were not consistent with the physician's ratings. Factor analysis of the 18 measures showed strong associations among variables in 4 distinct domains: disease activity, RP measures, digital ulcer measures, and mood/tension. Reliability of the RCS, HAQ pain and disability scales, and AIMS2 mood and tension subscales was high. The RP measures demonstrated good sensitivity to change (effect sizes 0.33–0.76). Conclusion Our findings demonstrate that the significant activity, disability, pain, and psychological impact of RP and digital ulcers in SSc can be measured by a small set of valid and reliable outcome measures. These outcome measures provide information beyond the quantitative metrics of RP attacks. We propose a core set of measures for use in clinical trials of RP in SSc patients that includes the RCS, patient and physician VAS ratings of RP activity, a digital ulcer/infarct measure, measures of disability and pain (HAQ), and measures of psychological function (AIMS2).

Induction of acetylcholinesterase expression during apoptosis in various cell types

Abstract: Acetylcholinesterase (AChE) plays a key role in terminating neurotransmission at cholinergic synapses. AChE is also found in tissues devoid of cholinergic responses, indicating potential functions beyond neurotransmission. It has been suggested that AChE may participate in development, differentiation, and pathogenic processes such as Alzheimer's disease and tumorigenesis. We examined AChE expression in a number of cell lines upon induction of apoptosis by various stimuli. AChE is induced in all apoptotic cells examined as determined by cytochemical staining, immunological analysis, affinity chromatography purification, and molecular cloning. The AChE protein was found in the cytoplasm at the initiation of apoptosis and then in the nucleus or apoptotic bodies upon commitment to cell death. Sequence analysis revealed that AChE expressed in apoptotic cells is identical to the synapse type AChE. Pharmacological inhibitors of AChE prevented apoptosis. Furthermore, blocking the expression of AChE with antisense inhibited apoptosis. Therefore, our studies demonstrate that AChE is potentially a marker and a regulator of apoptosis.

Linkage disequilibrium between the beta frequency of the human EEG and a GABAA receptor gene locus.

Abstract: Human brain oscillations represent important features of information processing and are highly heritable. A common feature of beta oscillations (13–28 Hz) is the critical involvement of networks of inhibitory interneurons as pacemakers, gated by γ-aminobutyric acid type A (GABAA) action. Advances in molecular and statistical genetics permit examination of quantitative traits such as the beta frequency of the human electroencephalogram in conjunction with DNA markers. We report a significant linkage and linkage disequilibrium between beta frequency and a set of GABAA receptor genes. Uncovering the genes influencing brain oscillations provides a better understanding of the neural function involved in information processing.

Growth Cone Turning Induced by Direct Local Modification of Microtubule Dynamics

Abstract: Pathfinding by nerve growth cones depends on attractive and repulsive turning in response to a variety of guidance cues. Here we present direct evidence to demonstrate an essential and instructive role for microtubules (MTs) in growth cone steering. First, both growth cone attraction and repulsion induced by diffusible cues in culture can be completely blocked by low concentrations of drugs that specifically inhibit dynamic microtubule ends in the growth cone. Second, direct focal photoactivated release of the microtubule-stabilizing drug taxol on one side of the growth cone consistently induces attraction (turning toward the site of application). Using the focal pipette application method, we also show that local MT stabilization by taxol induces growth cone attraction, whereas local MT destabilization by the microtubule-disrupting drug nocodazole induces repulsion (turning away). Finally, the microtubule-initiated attractive turning requires the participation of the actin cytoskeleton: local microtubule stabilization induces preferential protrusion of lamellipodia before the attractive turning, and the attraction can be abolished by inhibition of either actin polymerization or the Rho family GTPases. Together, these results demonstrate a novel steering mechanism for growth cones in which local and selective modification of dynamic microtubules can initiate and instruct directional steering. With the subsequent concerted activity of the actin cytoskeleton, this microtubule-initiated mechanism provides the growth cone with the additional means to efficiently navigate through its environment.

Histone Deacetylase Activity Is Necessary for Oligodendrocyte Lineage Progression

Abstract: Gene expression can be modulated by chromatin changes induced by histone acetylation and deacetylation. Acetylation of histone lysine residues by acetyltransferases is associated with transcriptionally active chromatin, whereas the removal of acetyl groups by histone deacetylases (HDACs) correlates with repressed chromatin. Recent evidence has shown that histone deacetylation is responsible for restricting neuronal gene expression, whereas histone acetylation is necessary for astrocytic differentiation We now asked whether histone acetylation or deacetylation was necessary for oligodendrocyte differentiation. Neonatal rat cortical progenitors were kept proliferating and undifferentiated in the presence of mitogens and induced to stop proliferating and differentiate into oligodendrocytes by mitogen removal. Histone deacetylation was observed during the temporal window between exit from the cell cycle and onset of differentiation, which was characterized by acquisition of branched morphology and myelin gene expression. Blocking HDAC activity during this critical window using the inhibitor trichostatin A (TSA) prevented the progression of progenitors into mature oligodendrocytes. TSA-treated progenitors were able to exit from the cell cycle but did not progress to oligodendrocytes. Their development was arrested at the progenitor stage, characterized by simple morphology and lack of myelin gene expression. The effect of TSA on progenitor differentiation was lineage specific, because TSA did not affect the ability of these cells to differentiate into type II astrocytes when cultured in the presence of serum. From these data, we conclude that histone deacetylation is a necessary component of the oligodendrocyte differentiation program.

The Role of Poly(ADP-Ribose) Polymerase Activation in the Development of Myocardial and Endothelial Dysfunction in Diabetes

Abstract: Patients with diabetes exhibit a high incidence of diabetic cardiomyopathy and vascular complications, which underlie the development of retinopathy, nephropathy, and neuropathy and increase the risk of hypertension, stroke, and myocardial infarction. There is emerging evidence that the activation of the nuclear enzyme poly(ADP-ribose) polymerase (PARP) importantly contributes to the development of endothelial dysfunction in a streptozotocin-induced model of diabetes. We investigated the role of PARP activation in the pathogenesis of cardiac dysfunction in streptozotocin-induced and genetic (nonobese diabetic) models of diabetes in rats and mice. Development of diabetes was accompanied by hyperglycemia, cardiac PARP activation, a selective loss of endothelium-dependent vasodilation in the thoracic aorta, and an early diastolic dysfunction of the heart. Treatment with a novel potent phenanthridinone-based PARP inhibitor, PJ34, starting 1 week after the onset of diabetes, restored normal vascular responsiveness and significantly improved cardiac dysfunction, despite the persistence of severe hyperglycemia. The beneficial effect of PARP inhibition persisted even after several weeks of discontinuation of the treatment. Thus, PARP activation plays a central role in the pathogenesis of diabetic cardiovascular (cardiac as well as endothelial) dysfunction. PARP inhibitors may exert beneficial effects against the development of cardiovascular complications in diabetes.

Validity of Self-rated Health among Latino(a)s

Abstract: The authors investigated whether self-rated health (SRH) had differential mortality risks for Latino(a) adults of various acculturation statuses living in the United States. They used cumulative National Health Interview Survey data from 1989 to 1994 (n = 37,713) linked with the National Health Interview Survey Multiple Cause of Death data files (1,364 deaths) that match records from the National Death Index through 1997. The authors specified survival models to estimate the effect of SRH on mortality and further stratified their model by birth and duration in the United States as proxies for acculturation. These estimates were compared across strata. Poor SRH was found to be a weaker predictor of subsequent mortality risk among the less acculturated, although the overall risk among the aggregated sample is similar to the risk reported in previous studies. The relation between poor SRH and mortality risk increases with United States acculturation among Latinos. While poor SRH was significantly associated with short-term mortality among the least acculturated, this association did not persist beyond 2-year mortality risk. Health researchers wishing to use SRH to assess the physical health of multiethnic populations should at least control for levels of acculturation among respondents.