Elongation of very long-chain fatty acids is enhanced in X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is a progressive neurodegenerative disorder characterized by the accumulation of saturated and mono-unsaturated very long-chain fatty acids (VLCFA) and reduced peroxisomal VLCFA beta-oxidation activity. In this study, we investigated the role of VLCFA biosynthesis in X-ALD fibroblasts. Our data demonstrate that elongation of both saturated and mono-unsaturated VLCFAs is enhanced in fibroblasts from patients with peroxisomal beta-oxidation defects including X-ALD, and peroxisome biogenesis disorders. These data indicate that enhanced VLCFA elongation is a general phenomenon associated with an impairment in peroxisomal beta-oxidation, and not specific for X-ALD alone. Analysis of plasma samples from patients with X-ALD and different peroxisomal beta-oxidation deficiencies revealed increased concentrations of VLCFAs up to 32 carbons. We infer that enhanced elongation does not result from impaired peroxisomal beta-oxidation alone, but is due to the additional effect of unchecked chain elongation. We demonstrate that elongated VLCFAs are incorporated into complex lipids. The role of chain elongation was also studied retrospectively in samples from patients with X-ALD previously treated with "Lorenzo's oil." We found that the decrease in plasma C26:0 previously found is offset by the increase of mono-unsaturated VLCFAs, not measured previously during the trial. We conclude that evaluation of treatment protocols for disorders of peroxisomal beta-oxidation making use of plasma samples should include the measurement of saturated and unsaturated VLCFAs of chain lengths above 26 carbon atoms. We also conclude that chain elongation offers an interesting target to be studied as a possible mode of treatment for X-ALD and other peroxisomal beta-oxidation disorders.     

Micropuncture studies on the influence of antidiuretic hormone on tubular fluid reabsorption in rats with hereditary hypothalamic diabetes insipidus

Summary Micropuncture studies were carried out on rats with hereditary hypothalamic diabetes insipidus, in order to measure net sodium and water reabsorption in proximal convolutions and short loops of Henle during water diuresis and ADH-induced antidiuresis. Intravenous infusion of 0.15 mU ADH per minute reduced urine flow from 74.5 l per kidney per minute to 10.8 l, and increased urine osmolality from 117 to 605 mOsm/kg. These changes could be reversed by stopping ADH.ADH did not alter the fractional reabsorption of fluid or the reabsorptive capacity for sodium in the proximal tubules. Nor did it change glomerular filtration rates of single superficial nephrons or of the entire kidney.Fractional reabsorption of the glomerular filtrate up to the early distal convolution was significantly higher (82.0%) in water diuresis than in antidiuresis (74.4%). Since this reabsorption remained unchanged in the proximal convolutions, the decreased reabsorption during antidiuresis must have occurred in the short loops. Fractional reabsorption of sodium up to the early distal tubule was essentially identical during water diuresis and antidiuresis, indicating that ADH does not enhance urinary concentration by increasing the reabsorption of sodium from short loops.On leave of absence from the Department of Physiology, Dartmouth Medical School, Hannover, N. H., from January to June, 1967. Recipient of USPHS Research Career Program Award 5-K3-GM-21, 786.     

Binding of Cellular Proteins to the Leader RNA of Equine Arteritis Virus

The genome of equine arteritis virus (EAV) produces a 3 coterminal-nested set of six subgenomic (sg) viral RNAs during virus replication cycle, and each set possesses a common leader sequence of 206 nucleotides (nt) in length derived from the 5 end of the viral genome. Given the presence of the leader region within both genomic and sg mRNAs, it is likely to contain cis-acting signals that may interact with cellular or viral proteins for RNA synthesis. Gel mobility shift assays indicated that proteins in Vero cell cytoplasmic extracts formed complexes with the positive (+) and negative (-) strands of the EAV leader RNA. Several cell proteins with molecular masses ranging from 74 to 31 kDa and 58 to 32 kDa were detected in UV-induced cross-linking assays with the EAV leader RNA (+) and (-) strands, respectively. In both cases, intense bands were observed at the 58–52 kDa molecular weight markers. Results from competition gel mobility shift assays using overlapping cold RNA probes spanning the leader RNA (+) strand indicated that nt 140–206 are not necessary for binding to cell proteins.     

Prevalence of fragilysin gene in Bacteroides fragilis isolates from blood and other extraintestinal samples

Of 166 Bacteroides fragilis isolates, 26.2% of 103 isolates from blood and 20.6% of 63 extraintestinal isolates harbored the fragilysin gene (difference not statistically significant). Clinical characteristics and evolution were comparable in patients with B. fragilis bacteremia with or without this enterotoxin. Fragilysin seems not to be an important virulence factor in B. fragilis disease.     

Activation of human neutrophils by the pollutant sodium sulfite: effect on cytokine production,chemotaxis, and cell surface expression of cell adhesion molecules

In chronic beryllium disease (CBD), a granulomatous lung disease characterized by hypersensitivity to beryllium salts (BE), BE challenge of bronchoalveolar lavage cells induces IFNgamma. Although nitric oxide (NO) is elevated in CBD airways, the effects of NO on CBD IFNgamma responses are unknown. Here we report that BE-stimulated IFNgamma production in CBD lavage cells was markedly reduced (74%) by the NO generator DETA NONOate. Investigation of IFNgamma-stimulatory cytokine involvement indicated that lavage cell IL-18 was significantly increased (fourfold) by BE and reduced (64%) by DETA NONOate but IL-12 was undetectable. IL-18 production was caspase-1-dependent but caspase 1 inhibition reduced IFNgamma only partially (43%). Specific antibody depletion of lavage cell IL-18 yielded marginal reduction (19%) of IFNgamma. Data are the first to show that: (1) BE stimulates IL-18 as well as IFNgamma in CBD; (2) BE cytokine responses are NO-sensitive; and (3) NO down-regulation of IFNgamma involves other sites in addition to IL-18.     

EMG power spectra of elbow extensors during ramp and step isometric contractions

Summary The goal of the present study was to compare electromyogram (EMG) power spectra obtained from step (constant force level) and ramp (progressive increase in the force level) isometric contractions. Data windows of different durations were also analysed for the step contractions, in order to evaluate the stability of EMG power spectrum statistics. Fourteen normal subjects performed (1) five ramp elbow extensions ranging from 0 to 100% of the maximum voluntary contraction (MVC) and (2) three stepwise elbow extensions maintained at five different levels of MVC. Spectral analysis of surface EMG signals obtained from triceps brachii and anconeus was performed. The mean power frequency (MPF) and the median frequency (MF) of each power spectrum were obtained from 256-ms windows taken at 10, 20, 40, 60 and 80% MVC for each type of contraction and in addition on 512-, 1024-and 2048-ms windows for the step contractions. No significant differences (P>0.05) were found in the values of both spectral statistics between the different window lengths. Even though no significant differences (P>0.05) were found between the ramp and the step contractions, significant interactions (P<0.05) between these two types of contraction and the force level were found for both the MPF and the MF data. These interactions point out the existence of different behaviours for both the MPF and the MF across force levels between the two types of contraction.     

Bilateral cataract and high serum ferritin: a new dominant genetic disorder?

This paper reports the cosegregation in a three generation pedigree of dominantly inherited cataract with an abnormally high level of serum ferritin. In this family, circulating L ferritin was raised in all subjects affected by cataract independently of iron overload. We suggest that a disorder of ferritin metabolism could be a new genetic disorder leading to lens opacity. Cataract-hyperferritaemia syndrome could also be a new contiguous gene syndrome involving the L ferritin gene and the gene coding for the lens membrane protein (MP19), which both map to the same region of chromosome 19q.     

Blastogenesis and Lymphokine Synthesis by T and B Lymphocytes from Patients with Periodontal Disease

Thymus-derived (T) and bone marrow-derived (B) lymphocytes were isolated from human peripheral blood and cultured with various mitogens and antigens. Purified protein derivative of tuberculin stimulated both purified T and B cells from patients with positive skin reactivity to purified protein derivative but did not stimulate nonimmune lymphocytes. Similarly, both T and B lymphocytes from patients with periodontal disease were stimulated to proliferate when incubated with dental plaque, whereas cells from normal individuals without gingivitis were unresponsive. In contrast, one component of plaque, bacterial endotoxins (lipopolysaccharide), minimally stimulated B lymphocytes from both normal or gingivitis patients. T lymphocytes from patients with periodontal disease were also stimulated by plaque antigen to produce chemotactic lymphokine activity (CTX) for human monocytes. B cells purified by the EAC rosetting method nonspecifically produced CTX without concomitant blastogenesis; however, after dissociation of adherent EAC these immune B cells did not spontaneously produce CTX. Lymphokine synthesis by B cells was not dependent on concomitant blastogenesis. Dissociated B cells from periodontitis patients also produced CTX activity after stimulation with dental plaque antigen. Therefore, both T and B lymphocytes, after stimulation with nonendotoxin antigenic components of plaque, proliferated and produced lymphokines, which are presumed to contribute to the pathogenesis of periodontal disease.     

A 1463 gene cattle-human comparative map with anchor points defined by human genome sequence coordinates

A second-generation 5000 rad radiation hybrid (RH) map of the cattle genome was constructed primarily using cattle ESTs that were targeted to gaps in the existing cattle-human comparative map, as well as to sparsely populated map intervals. A total of 870 targeted markers were added, bringing the number of markers mapped on the RH(5000) panel to 1913. Of these, 1463 have significant BLASTN hits (E < e(-5)) against the human genome sequence. A cattle-human comparative map was created using human genome sequence coordinates of the paired orthologs. One-hundred and ninety-five conserved segments (defined by two or more genes) were identified between the cattle and human genomes, of which 31 are newly discovered and 34 were extended singletons on the first-generation map. The new map represents an improvement of 20% genome-wide comparative coverage compared with the first-generation map. Analysis of gene content within human genome regions where there are gaps in the comparative map revealed gaps with both significantly greater and significantly lower gene content. The new, more detailed cattle-human comparative map provides an improved resource for the analysis of mammalian chromosome evolution, the identification of candidate genes for economically important traits, and for proper alignment of sequence contigs on cattle chromosomes.