Showing papers by "Humboldt University of Berlin published in 1998"
TL;DR: These findings represent the first examples of a genetic defect within the POMC gene and define a new monogenic endocrine disorder resulting in early–onset obesity, adrenal insufficiency and red hair pigmentation.
Abstract: Sequential cleavage of the precursor protein pre-pro-opiomelanocortin (POMC) generates the melanocortin peptides adrenocorticotrophin (ACTH), melanocyte-stimulating hormones (MSH) alpha, beta and gamma as well as the opioid-receptor ligand beta-endorphin. While a few cases of isolated ACTH deficiency have been reported (OMIM 201400), an inherited POMC defect has not been described so far. Recent studies in animal models elucidated a central role of alpha-MSH in the regulation of food intake by activation of the brain melanocortin-4-receptor (MC4-R; refs 3-5) and the linkage of human obesity to chromosome 2 in close proximity to the POMC locus, led to the proposal of an association of POMC with human obesity. The dual role of alpha-MSH in regulating food intake and influencing hair pigmentation predicts that the phenotype associated with a defect in POMC function would include obesity, alteration in pigmentation and ACTH deficiency. The observation of these symptoms in two probands prompted us to search for mutations within their POMC genes. Patient 1 was found to be a compound heterozygote for two mutations in exon 3 (G7013T, C7133delta) which interfere with appropriate synthesis of ACTH and alpha-MSH. Patient 2 was homozygous for a mutation in exon 2 (C3804A) which abolishes POMC translation. These findings represent the first examples of a genetic defect within the POMC gene and define a new monogenic endocrine disorder resulting in early-onset obesity, adrenal insufficiency and red hair pigmentation.
1,613 citations
TL;DR: The positional cloning of a gene encoding a novel protein, nibrin, which contains two modules found in cell cycle checkpoint proteins, a forkhead-associated domain adjacent to a breast cancer carboxy-terminal domain and a truncating 5 bp deletion are described.
1,052 citations
TL;DR: It is shown that co-expression of the mutant ß1 subunit with a brain Na+-channel ß subunit in Xenopus laevis oocytes demonstrates that the mutation interferes with the ability of the subunit to modulate channel-gating kinetics consistent with a loss-of-function allele, developing the theme that idiopathic epilepsies are a family of channelopathies.
Abstract: Febrile seizures affect approximately 3% of all children under six years of age and are by far the most common seizure disorder. A small proportion of children with febrile seizures later develop ongoing epilepsy with afebrile seizures. Segregation analysis suggests the majority of cases have complex inheritance but rare families show apparent autosomal dominant inheritance. Two putative loci have been mapped (FEB1 and FEB2), but specific genes have not yet been identified. We recently described a clinical subset, termed generalized epilepsy with febrile seizures plus (GEFS+), in which many family members have seizures with fever that may persist beyond six years of age or be associated with afebrile generalized seizures. We now report linkage, in another large GEFS+ family, to chromosome region 19q13.1 and identification of a mutation in the voltage-gated sodium (Na+)-channel beta1 subunit gene (SCN1B). The mutation changes a conserved cysteine residue disrupting a putative disulfide bridge which normally maintains an extracellular immunoglobulin-like fold. Co-expression of the mutant beta1 subunit with a brain Na+-channel alpha subunit in Xenopus laevis oocytes demonstrates that the mutation interferes with the ability of the subunit to modulate channel-gating kinetics consistent with a loss-of-function allele. This observation develops the theme that idiopathic epilepsies are a family of channelopathies and raises the possibility of involvement of other Na+-channel subunit genes in febrile seizures and generalized epilepsies with complex inheritance patterns.
1,015 citations
TL;DR: Monitoring patients with childhood ALL at consecutive time points gives clinically relevant insight into the effectiveness of treatment, and combined information on MRD from the first 3 months of treatment distinguishes patients with good prognoses from those with poor prognose, and this helps in decisions whether and how to modify treatment.
907 citations
TL;DR: With a calculated prevalence of 1.9%, spondylarthropathies are among the most frequent rheumatic diseases in the white population and HLA-B27 positive persons carry a 20-fold increased risk of developing SpA.
Abstract: Objective
To determine the overall prevalence of spondylarthropathy (SpA) among whites.
Methods
To screen for SpA symptoms, such as inflammatory back pain (IBP), joint swelling, psoriasis, and uveitis, or a specific family history, questionnaires were mailed to 348 blood donors (174 HLA-B27 positive and 174 HLA-B27 negative). From the responding 273 persons (78%; 140 B27 positive, 133 B27 negative), 126 were selected for further evaluation based on the symptoms reported. Of this group, 90 persons agreed to undergo physical examination (71.4%; 46 B27 positive, 44 B27 negative). There was no difference between the B27-positive and -negative groups in terms of age (mean ± SD 38.4 ± 10 versus 39.5 ± 11 years) and sex ratio (67% versus 68% were men). In addition, 58 donors (32 B27 positive, 26 B27 negative) agreed to undergo magnetic resonance imaging (MRI) of the sacroiliac joints. A diagnosis of SpA and ankylosing spondylitis (AS) was made according to the European Spondylarthropathy Study Group criteria and the New York criteria.
Results
SpA was diagnosed in 20 persons: 19 of 140 B27-positive (13.6%) and 1 of 133 B27-negative (0.7%) subjects (15 male and 5 female). AS was diagnosed in 9 persons (7 male and 2 female; 45%), undifferentiated SpA (USpA) in 7 (5 male and 2 female; 35%), psoriatic arthritis (PsA) in 3 (2 male and 1 female; 15%), and chronic reactive arthritis (ReA; Reiter's syndrome) in 1 (male; 5%). On the basis of a B27 frequency of 9.3% among the population of Berlin (3.47 million persons), the estimated prevalence of SpA was 1.9%, AS was 0.86%, USpA was 0.67%, and PsA was 0.29%. The relative risk of developing SpA in B27-positive subjects was calculated as 20.7 (95% confidence interval 4.6-94.2; P = 0.001). Of 58 persons with IBP, sacroiliitis was detected by MRI in 15 of 32 B27-positive (46.9%) and 1 of 26 B27-negative (3.9%) subjects (P = 0.002). Four of these 16 donors did not fulfill diagnostic criteria for SpA.
Conclusion
With a calculated prevalence of 1.9%, spondylarthropathies are among the most frequent rheumatic diseases in the white population. HLA-B27 positive persons carry a 20-fold increased risk of developing SpA. AS and USpA are the most frequent SpA subtypes. Persons with IBP who are B27 positive have a 50% likelihood of having sacroiliitis.
903 citations
TL;DR: In this paper, the Big Five factors of personality, the subfactors Sociability and Shyness, and all significant social relationships were repeatedly assessed by 132 students after entering university.
Abstract: Personality influences on social relationships and vice versa were longitudinally studied. Personality affected relationships, but not vice versa. After entry to university, 132 students participated for 18 month in a study in which the Big Five factors of personality, the subfactors Sociability and Shyness, and all significant social relationships were repeatedly assessed. A subsample kept diaries of all significant social interactions. After the initial correlation between personality and relationship quality was controlled for, Extraversion and its subfactors, Agreeableness, and Conscientiousness predicted aspects of relationships such as number of peer relationships, conflict with peers, and falling in love. In contrast, relationship qualities did not predict personality traits, and changes in relationship qualities were unrelated to changes in personality traits. Consequences for dynamic-interactionistic views of personality and relationships are discussed.
744 citations
TL;DR: Investigating whether increased activation of NFκB is important in IBD and may be down-regulated by anti-inflammatory treatment found it may be involved in the regulation of the inflammatory response in both IBDs and particularly Crohn’s disease.
Abstract: Background —Expression of pro-inflammatory cytokines is increased in the intestinal lamina propria of patients with inflammatory bowel disease (IBD). Nuclear factor κB (NFκB) controls transcription of inflammation genes. On activation, NFκB is rapidly released from its cytoplasmic inhibitor (IκB), transmigrates into the nucleus, and binds to DNA response elements in gene promoter regions. Aims —To investigate whether increased activation of NFκB is important in IBD and may be down-regulated by anti-inflammatory treatment. Methods —Activation of NFκB was determined by western blot assessment and electrophoretic mobility shift assay in nuclear extracts of colonic biopsy samples as well as lamina propria mononuclear cells. Results —Nuclear levels of NFκB p65 are increased in lamina propria biopsy specimens from patients with Crohn’s disease in comparison with patients with ulcerative colitis and controls. Increased activation of NFκB was detected in lamina propria mononuclear cells from patients with active IBD. Corticosteroids strongly inhibit intestinal NFκB activation in IBD in vivo and in vitro by stabilising the cytosolic inhibitor IκBα against activation induced degradation. Conclusions —In both IBDs, but particularly Crohn’s disease, increased activation of NFκB may be involved in the regulation of the inflammatory response. Inhibition of NFκB activation may represent a mechanism by which steroids exert an anti-inflammatory effect in IBD.
709 citations
TL;DR: Within this prospective, randomized trial, laparoscopic techniques were as safe as conventional surgical techniques and offered a faster recovery of pulmonary and gastrointestinal function compared with conventional surgery for selected patients undergoing large bowel resection for cancer or polyps.
Abstract: Background: Uncontrolled studies using laparoscopic techniques in colorectal surgery have not demonstrated clear advantages to these procedures compared with conventional ones, and surgeons are concerned about unusual early recurrences reported after laparoscopic colorectal cancer surgery. Study Design: We conducted a prospective, randomized trial in one surgical department comparing laparoscopic (LAP) and conventional (CON) techniques in 109 patients undergoing bowel resection for colorectal cancers or polyps. Postoperatively, all patients underwent measurement of pulmonary function tests every 12 hours, and were treated identically on a highly controlled protocol with regard to analgesic administration, feeding, and postoperative care. Results: Of the 55 patients assigned to LAP and 54 to the CON group, there were 42 and 38 with cancer, respectively (the other patients had large adenomas). Overall recovery of 80% of forced expiratory volume in 1 second and forced vital capacity was a median of 3 days for LAP and 6.0 days for CON (p = 0.01). LAP patients used significantly less morphine than CON patients up to the second day after surgery (0.78 ± 0.32 versus 0.92 ± 0.34 mg/kg per day, p=0.02). Flatus returned a median of 3.0 days after LAP versus 4.0 days after CON surgery (p = 0.006). Tumor margins were clear in all patients. After a median followup of 1.5 years (LAP) and 1.7 years (CON), there were no port site recurrences in the LAP group. Seven cancer-related deaths have occurred (three in the LAP group, four in the CON group). Conclusions: Within this prospective, randomized trial, laparoscopic techniques were as safe as conventional surgical techniques and offered a faster recovery of pulmonary and gastrointestinal function compared with conventional surgery for selected patients undergoing large bowel resection for cancer or polyps. There were no apparent shortterm oncologic disadvantages. Longer followup is needed to fully assess oncologic outcomes.
657 citations
TL;DR: In this paper, the single oxygen quantum yields of different phthalocyanines and tris(2,2″-bipyridyl)ruthenium(II) dichloride in dimethylformamide (DMF) or aqueous micellar solution of 0.1 M CTAC (cetyltrimethylammonium chloride).
Abstract: The singlet oxygen luminescence method and the photochemical methods using 1,3-diphenylisobenzofuran (DPBF) or bilirubin ditaurate (BDT) as chemical quenchers were employed to determine the single oxygen quantum yields (ΦΔ) of different phthalocyanines and tris(2,2″-bipyridyl)ruthenium(II) dichloride in dimethylformamide (DMF) or aqueous micellar solution of 0.1 M CTAC (cetyltrimethylammonium chloride). Additionally, a perylenetetracarboxylic acid diimide derivative was examined in DMF. In a series of tetrasulfonated phthalocyanines (PTS) the following order was found: ZnPTS > GaPTS > AlPTS ≈ H2PTS > CoPTS. In general, the singlet oxygen quantum yields are higher in DMF than in 0.1 M CTAC/H2O. The results obtained with the photochemical systems are comparable with those obtained by the photophysical method. The photochemical DPBF method results in absolute values of ΦΔ. However, in micellar solution, chain reactions occur when DPBF is used as chemical quencher in the photo-oxidative process. This problem ...
638 citations
TL;DR: It is shown that forces generated by ac fields under conditions of negative dielectrophoresis (DEP) can also be used and the combination of this new method with high-performance optical detection offers prospects for miniaturized flow cytometry.
Abstract: There are highly sensitive analytical techniques for probing cellular and molecular events in very small volumes. The development of microtools for effective sample handling and separation in such volumes remains a challenge. Most devices developed so far use electrophoretic and chromatographic separation methods. We show that forces generated by ac fields under conditions of negative dielectrophoresis (DEP) can also be used. Miniaturized electrode arrays are housed in a microchannel and driven with high-frequency ac. A laminar liquid flow carries particles past the electrodes. Modification of the ac drive changes the particle trajectories. We have handled latex particles of micrometer size and living mammalian cells in a device which consists of the following four elements: a planar funnel which concentrates particles from a 1-mm-wide stream to a beam of about 50-μm width, an aligner which narrows the beam further and acts to break up particle aggregates, a field cage which can be used to trap particles,...
551 citations
TL;DR: In this paper, the authors tested the hypothesis that inflammation is reflected by signal changes in contrastenhanced magnetic resonance imaging (MRI) and assessed 44 consecutive patients with symptoms of acute myocarditis, and 19 patients met the inclusion criteria revealing ECG changes, reduced myocardial function, elevated creatine kinase, positive troponin T, serological evidence for acute viral infection, exclusion of coronary heart disease, and positive antimyosin scintigraphy.
Abstract: Background—The course of tissue changes in acute myocarditis in humans is not well understood. Diagnostic tools currently available are unsatisfactory. We tested the hypothesis that inflammation is reflected by signal changes in contrast-enhanced magnetic resonance imaging (MRI). Methods and Results—We assessed 44 consecutive patients with symptoms of acute myocarditis. Nineteen patients met the inclusion criteria revealing ECG changes, reduced myocardial function, elevated creatine kinase, positive troponin T, serological evidence for acute viral infection, exclusion of coronary heart disease, and positive antimyosin scintigraphy. We studied these patients on days 2, 7, 14, 28, and 84 after the onset of symptoms. We obtained ECG-triggered, T1-weighted images before and after application of 0.1 mmol/kg gadolinium. We measured the global relative signal enhancement of the left ventricular myocardium related to skeletal muscle and compared it with measurements in 18 volunteers. The global relative enhanceme...
TL;DR: FMRI results suggest that attentive tracking is mediated by a network of areas that includes parietal and frontal regions responsible for attention shifts and eye movements and the MT complex, thought to be responsible for motion perception.
Abstract: Culham, Jody C., Stephan A. Brandt, Patrick Cavanagh, Nancy G. Kanwisher, Anders M. Dale, and Roger B. H. Tootell. Cortical fMRI activation produced by attentive tracking of moving targets. J. Neur...
TL;DR: In this review, recent data concerning the properties and putative role of the ATP-hydrolyzing subunits/domains are summarized and compared between bacterial and eukaryotic systems.
Abstract: Members of the superfamily of adenosine triphosphate (ATP)-binding-cassette (ABC) transport systems couple the hydrolysis of ATP to the translocation of solutes across a biological membrane. Recognized by their common modular organization and two sequence motifs that constitute a nucleotide binding fold, ABC transporters are widespread among all living organisms. They accomplish not only the uptake of nutrients in bacteria but are involved in diverse processes, such as signal transduction, protein secretion, drug and antibiotic resistance, antigen presentation, bacterial pathogenesis and sporulation. Moreover, some human inheritable diseases, like cystic fibrosis, adrenoleukodystrophy and Stargardt's disease are caused by defective ABC transport systems. Thus, albeit of major significance, details of the molecular mechanism by which these systems exert their functions are still poorly understood. In this review, recent data concerning the properties and putative role of the ATP-hydrolyzing subunits/domains are summarized and compared between bacterial and eukaryotic systems.
TL;DR: Three point mutations in the coding region of PAX8 are reported in two sporadic patients and one familial case of TD, implicate PAX8 in the pathogenesis of TD and in normal thyroid development.
Abstract: Permanent congenital hypothyroidism (CH) is a common disease that occurs in 1 of 3,000–4,000 newborns. Except in rare cases due to hypothalamic or pituitary defects, CH is characterized by elevated levels of thyroid-stimulating hormone (TSH) resulting from reduced thyroid function. When thyroid hormone therapy is not initiated within the first two months of life, CH can cause severe neurological, mental and motor damage1,2. In 80–85% of cases, CH is associated with and presumably is a consequence of thyroid dysgenesis (TD). In these cases, the thyroid gland can be absent (agenesis, 35–40%), ectopically located (30–45%) and/or severely reduced in size (hypoplasia, 5%). Familial cases of TD are rare, even though ectopic or absent thyroid has been occasionally observed in siblings3. The pathogenesis of TD is still largely unknown. Although a genetic component has been suggested, mutations in the gene encoding the receptor for the thyroid-stimulating hormone (TSHR) have been identified in only two cases of TD with hypoplasia4,5. We report mutations in the coding region of PAX8 in two sporadic patients and one familial case of TD. All three point mutations are located in the paired domain of PAX8 and result in severe reduction of the DMA-binding activity of this transcription factor. These genetic alterations implicate PAX8 in the pathogenesis of TD and in normal thyroid development.
TL;DR: It is found that in a rat model of acute brain injury, the βreceptor antagonist propranolol prevented the increase of interleukin-10 plasma levels and this may represent a common pathway for immunodepression induced by stress and injury.
Abstract: The mechanism of immunodepression after brain injury is not yet clear. Here we demonstrate rapid systemic release of the immunoinhibitory cytokine interleukin-10, monocytic deactivation and a high incidence of infection in patients with 'sympathetic storm' due to acute accidental or iatrogenic brain trauma. In vitro studies showed that within minutes catecholamines trigger the secretion of interleukin-10 from unstimulated monocytes through a beta-adrenoreceptor-mediated, cAMP/protein kinase A-dependent pathway. We found that in a rat model of acute brain injury, the beta-receptor antagonist propranolol prevented the increase of interleukin-10 plasma levels. Rapid monocytic interleukin-10 release after sympathetic activation may represent a common pathway for immunodepression induced by stress and injury.
TL;DR: The 20S proteasome was more resistant to oxidative stress than the ATP- and ubiquitin-dependent 26S proteasant system, and Lysates from K562 cells are able to degrade oxidized ferritin at a higher rate than non-oxidized ferrisin, in an ATP-independent manner.
Abstract: Oxidatively modified ferritin is selectively recognized and degraded by the 20S proteasome. Concentrations of hydrogen peroxide (H2O2) higher than 10 micromol/mg of protein are able to prevent proteolytic degradation. Exposure of the protease to high amounts of oxidants (H2O2, peroxynitrite and hypochlorite) inhibits the enzymic activity of the 20S proteasome towards the fluorogenic peptide succinyl-leucine-leucine-valine-tyrosine-methylcoumarylamide (Suc-LLVY-MCA), as well as the proteolytic degradation of normal and oxidant-treated ferritin. Fifty per cent inhibition of the degradation of the protein substrates was achieved using 40 micromol of H2O2/mg of proteasome. No change in the composition of the enzyme was revealed by electrophoretic analysis up to concentrations of 120 micromol of H2O2/mg of proteasome. In further experiments, it was found that the 26S proteasome, the ATP- and ubiquitin-dependent form of the proteasomal system, is much more susceptible to oxidative stress. Whereas degradation of the fluorogenic peptide, Suc-LLVY-MCA, by the 20S proteasome was inhibited by 50% with 12 micromol of H2O2/mg, 3 micromol of H2O2/mg was enough to inhibit ATP-stimulated degradation by the 26S proteasome by 50%. This loss in activity could be followed by the loss of band intensity in the non-denaturing gel. Therefore we concluded that the 20S proteasome was more resistant to oxidative stress than the ATP- and ubiquitin-dependent 26S proteasome. Furthermore, we investigated the activity of both proteases in K562 cells after H2O2 treatment. Lysates from K562 cells are able to degrade oxidized ferritin at a higher rate than non-oxidized ferritin, in an ATP-independent manner. This effect could be followed even after treatment of the cells with H2O2 up to a concentration of 2mM. The lactacystin-sensitive ATP-stimulated degradation of the fluorogenic peptide Suc-LLVY-MCA declined, after treatment of the cells with 1mM H2O2, to the same level as that obtained without ATP stimulation. Therefore, we conclude that the regulation of the 20S proteasome by various regulators takes place during oxidative stress. This provides further evidence for the role of the 20S proteasome in the secondary antioxidative defences of mammalian cells.
TL;DR: Measurements of sites sensitive to S1 nuclease treatment in telomeres, in minisatellites, and in the bulk of the genome of fibroblasts under different models of oxidative stress as well as after treatment with the alkylating agent reveal single-stranded regions in the DNA.
TL;DR: It is demonstrated that cells distinguish a premature termination codon within the β‐globin mRNA from the physiological translation termination codons by a two‐step specification mechanism, and a common principle for nonsense‐mediated decay from yeast to man is proposed.
Abstract: Premature translation termination codons resulting from nonsense or frameshift mutations are common causes of genetic disorders. Complications arising from the synthesis of C-terminally truncated polypeptides can be avoided by 'nonsense-mediated decay' of the mutant mRNAs. Premature termination codons in the beta-globin mRNA cause the common recessive form of beta-thalassemia when the affected mRNA is degraded, but the more severe dominant form when the mRNA escapes nonsense-mediated decay. We demonstrate that cells distinguish a premature termination codon within the beta-globin mRNA from the physiological translation termination codon by a two-step specification mechanism. According to the binary specification model proposed here, the positions of splice junctions are first tagged during splicing in the nucleus, defining a stop codon operationally as a premature termination codon by the presence of a 3' splicing tag. In the second step, cytoplasmic translation is required to validate the 3' splicing tag for decay of the mRNA. This model explains nonsense-mediated decay on the basis of conventional molecular mechanisms and allows us to propose a common principle for nonsense-mediated decay from yeast to man.
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01 Jan 1998TL;DR: In this paper, agenda, agency, and aims of Central East European transitions have been discussed and a mapping of Eastern Europe has been proposed, where the unfinished project of the Central Eastern European transition has been discussed.
Abstract: 1. Introduction: agenda, agency, and aims of Central East European transitions 2. Mapping Eastern Europe 3. Constitutional politics in Eastern Europe 4. Building and consolidating democracies 5. Building capitalism in Eastern Europe 6. Social policy transformation 7. Consolidation and the cleavages of ideology and identity 8. Conclusion: the unfinished project.
TL;DR: The data show for the first time that the amygdala is active in human phobics when they are exposed to potentially fear-relevant stimuli.
Abstract: Functional magnetic resonance imaging was used to determine the activation of the amygdala while seven social phobics and five healthy controls were exposed to slides of neutral faces as well as aversive odor stimuli. The amygdala was selectively activated in the social phobics during presentation of the face stimuli. The data show for the first time that the amygdala is active in human phobics when they are exposed to potentially fear-relevant stimuli. Further research is needed to determine the extent to which overactivation of the amygdala precedes or is a consequence of phobia.
TL;DR: There is a significant increase in left-ventricular mass in patients with dilated cardiomyopathy given rhGH but this is not accompanied by an improvement in clinical status.
TL;DR: In this article, the Hartree−Fock method is combined with ab initio shell model potentials (Pot) for the periodic zeolite framework and its interaction with ammonia and ammonium ions.
Abstract: The influence of the zeolite framework type (FAU, CHA, MOR, MFI) and the crystallographic position on the acidity of zeolites is investigated. The most stable Bronsted acid sites of the high-silica frameworks are considered: O1−H (FAU), O1−H (CHA), Al4−O2(H)−Si (MOR), and Al7−O17(H)−Si4 (MFI, sinusoidal channel). The latter is compared with the less stable Al12-O24(H)-Si12 position (MFI, channel intersection). Both the heat of the deprotonation and the heat of ammonia adsorption are considered as measures of acid strength. A novel hybrid computational scheme is used that combines the quantum mechanical cluster description (QM) of the active site with interatomic potentials (Pot) for the periodic zeolite framework. Specifically, the Hartree−Fock method (QM) is combined with ab initio shell model potentials (Pot) for the zeolite framework and its interaction with ammonia and ammonium ions. Complete relaxation of the framework is possible within this scheme and long-range corrections to the reaction energie...
TL;DR: The investigation of the possible expression of vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) in the human mast cell line HMC-1 and in human skin mast cells shows that both normal and leukemic human mast cells constitutively express bioactive VEGF.
Abstract: Mast cells have been implicated in various diseases that are accompanied by neovascularization. The exact mechanisms by which mast cells might mediate an angiogenic response, however, are unclear and therefore, we have investigated the possible expression of vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) in the human mast cell line HMC-1 and in human skin mast cells. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that mast cells constitutively express VEGF121, VEGF165, and VEGF189. After a prolonged stimulation of cells for 24 h with phorbol 12-myristate 13-acetate (PMA) and the ionophore A23187, an additional transcript representing VEGF206 was detectable, as could be verified by sequence analysis. These results were confirmed at the protein level by Western blot analysis. When the amounts of VEGF released under unstimulated and stimulated conditions were compared, a significant increase was detectable after stimulation of cells. Human microvascular endothelial cells (HMVEC) responded to the supernatant of unstimulated HMC-1 cells with a dose-dependent mitogenic effect, neutralizable up to 90% in the presence of a VEGF-specific monoclonal antibody. Flow cytometry and postembedding immunoelectron microscopy were used to detect VEGF in its cell-associated form. VEGF was exclusively detectable in the secretory granules of isolated human skin mast cells. These results show that both normal and leukemic human mast cells constitutively express bioactive VEGF. Furthermore, this study contributes to the understanding of the physiological role of the strongly heparin-binding VEGF isoforms, since these were found for the first time to be expressed in an activation-dependent manner in HMC-1 cells.
TL;DR: It is demonstrated that different molecular mechanisms contribute to a gradual development of fluconazole resistance in C. albicans.
Abstract: From each of two AIDS patients with oropharyngeal candidiasis, five Candida albicans isolates from recurrent episodes of infection which became gradually resistant against fluconazole during antimycotic treatment were analyzed for molecular changes responsible for drug resistance. In both patients, a single C. albicans strain was responsible for the recurrent infections, but the CARE-2 fingerprint pattern of the isolates exhibited minor genetic alterations, indicating that microevolution of the strains took place during fluconazole therapy. In the isolates from patient 1, enhanced mRNA levels of the MDR1 gene, encoding a multiple drug resistance protein from the superfamily of major facilitators, and constitutive high expression of the ERG11 gene, coding for the drug target enzyme sterol 14alpha-demethylase, correlated with a stepwise development of fluconazole resistance. The resistant strains exhibited reduced accumulation of fluconazole and, for the last in the series, a slight increase in drug needed to inhibit sterol 14alpha-demethylation in vitro. In the isolates from patient 2, increased MDR1 mRNA levels and the change from heterozygosity to homozygosity for a mutant form of the ERG11 gene correlated with continuously decreased drug susceptibility. In this series, reduced drug accumulation and increased resistance in the target enzyme activity, sterol 14alpha-demethylase, were observed. These results demonstrate that different molecular mechanisms contribute to a gradual development of fluconazole resistance in C. albicans.
TL;DR: The gene was identified as human XRCC9, a gene which has been shown to complement the MMC-sensitive Chinese hamster mutant UV40, and is suspected to be involved in DNA post-replication repair or cell cycle checkpoint control.
Abstract: Fanconi anemia (FA) is an autosomal recessive disease with diverse clinical symptoms including developmental anomalies, bone marrow failure and early occurrence of malignancies1. In addition to spontaneous chromosome instability, FA cells exhibit cell cycle disturbances and hypersensitivity to cross-linking agents1. Eight complementation groups (A-H) have been distinguished2, each group possibly representing a distinct FA gene3. The genes mutated in patients of complementation groups A (FANCA; Refs 4,5) and C (FANCC; ref. 6) have been identified, and FANCD has been mapped to chromosome band 3p22-26 (ref. 7). An additional FA gene has recently been mapped to chromosome 9p (ref. 8). Here we report the identification of the gene mutated in group G, FANCG, on the basis of complementation of an FA-G cell line and the presence of pathogenic mutations in four FA-G patients. We identified the gene as human XRCC9, a gene which has been shown to complement the MMC-sensitive Chinese hamster mutant UV40, and is suspected to be involved in DNA post-replication repair or cell cycle checkpoint control9,10. The gene is localized to chromosome band 9p13 (ref. 9), corresponding with a known localization of an FA gene.
TL;DR: It is concluded that acute phase LBP has a protective effect against LPS and bacterial infection and may represent a physiologic defense mechanism against infection.
Abstract: LPS-binding protein (LBP) recognizes bacterial LPS and transfers it to CD14, thereby enhancing host cell stimulation, eventually resulting in pathogenic states such as septic shock. Recently, LBP also was shown to detoxify LPS by transferring LPS into HDL particles in vitro. Thus, the predominant in vivo function of LBP has remained unclear. To investigate the biological activity of acute phase concentrations of recombinant murine LBP, high concentrations of LBP were investigated in vitro and in vivo. Although addition of low concentrations of LBP to a murine macrophage cell line enhanced LPS-induced TNF-alpha synthesis, acute phase concentrations of LBP blocked this effect in comparison to low-dose LBP. When injected into mice intraperitoneally, LBP inhibited LPS-mediated cytokine release and prevented hepatic failure resulting in a significantly decreased mortality rate in LPS-challenged and D-galactosamine-sensitized mice, as well as in a murine model of bacteremia. These results complement a recent study revealing LBP-deficient mice to be dramatically more susceptible to an intraperitoneal Salmonella infection as compared with normal mice. We conclude that acute phase LBP has a protective effect against LPS and bacterial infection and may represent a physiologic defense mechanism against infection. Despite the limitations of any murine sepsis model, the results shown may imply that LBP could have beneficial effects during gram-negative peritonitis in humans.
TL;DR: Many aquatic animal species can survive sulfide exposure to some extent through oxidation of the sulfide, which results mainly in thiosulfate, which requires oxygen and results in an increase in oxygen consumption of some species.
Abstract: Many aquatic animal species can survive sulfide exposure to some extent through oxidation of the sulfide, which results mainly in thiosulfate. In several species, sulfide oxidation is localized in the mitochondria and is accompanied by ATP synthesis. In addition, blood-based and intracellular compounds can augment sulfide oxidation. The formation of thiosulfate requires oxygen, which results in an increase in oxygen consumption of some species. If not all sulfide is detoxified, cytochrome c oxidase is inhibited. Under these conditions, a sulfide-dependent anaerobic energy metabolism commences.
TL;DR: The importance of an ensemble of muscle forces to reproduce a physiological strain distribution in the femur is demonstrated by using a finite element model to calculate stresses and strains of a femur with all thigh muscle and joint contact forces.
TL;DR: It is suggested that a variety of nonlinear phenomena including subharmonics, biphonation, and deterministic chaos are normally occurring phonatory events in mammalian vocalizations.
Abstract: To establish a framework for discussing mammalian vocalizations, relevant terminology and concepts from the theory of nonlinear dynamics are introduced. It is suggested that a variety of nonlinear phenomena including subharmonics, biphonation, and deterministic chaos are normally occurring phonatory events. The whole spectrum of these phenomena can be found in the repertoire of the African wild dog Lycaon pictus. In addition, examples of nonlinear phenomena in a wide range of other mammalian taxa will be presented. Moreover, some artifacts in sound spectrographic analysis are listed which may be misinterpreted as nonlinear phenomena. Within the framework of nonlinear dynamics, a consistent terminology is proposed and our observations are related to laryngeal sound production mechanisms. Finally, some hypotheses concerning the communicative potential of the described phenomena are discussed.
TL;DR: The clinical findings suggest a role for TI in the performance of fast and complex hand motor tasks and characterize the system of callosal fibers activated by transcranial magnetic brain stimulation in more detail as a basis for a diagnostic application of this technique.
Abstract: In 1 split-brain patient and 13 patients with circumscript surgical lesions within different parts of the corpus callosum (CC), the topography of fibers within the CC mediating an interhemispheric inhibition between the motor cortices was investigated in the phase of a stable disconnection syndrome. The aim of the study was to characterize the system of callosal fibers activated by transcranial magnetic brain stimulation in more detail as a basis for a diagnostic application of this technique. The locations and areas of the lesions were measured on sagittal magnetic resonance (MR) slices and attributed to five segments of the CC, because the borders of the anatomic subdivisions of the CC are not clearly defined. Transcallosal inhibition (TI) of tonic electromyographical hand muscle activity was elicited by focal transcranial magnetic stimulation over the primary motor cortex. In a reference group of normal subjects, TI started after 35.8+/-3.6 msec had a duration of 24.8+/-2.7 msec and an estimated transcallosal conduction time of 15.5+/-3.0 msec (range, 10.2-20.0 msec, n = 24 hands). No significant differences were found for the TI originating from the right and left motor cortices. From the absence and presence of TI in patients with lesions in different parts of the CC it can be concluded that most of the fibers mediating TI pass through the posterior third and anterior fourth segment of the CC, that is, through the posterior half of the trunk of the CC. The clinical findings suggest a role for TI in the performance of fast and complex hand motor tasks.