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Biomedical subjects

B Wolf

Publications and source records attributed to B Wolf.

At least 361 records · Page 20Linked to original sources
PubMed1978

Presymptomatic diagnosis of adult onset polycystic kidney disease by ultrasonography.

Results of an ongoing prospective study of progeny of patients with adult-onset polycystic kidney disease using grey-scale ultrasound and high-dose nephrotomography are reported. Six asymptomatic subjects out of 17 at risk for polycystic kidney disease were found by ultrasonography to have multiple renal cysts; this included two unrelated children aged 18 months and 6 y who had normal high-dose nephrotomography. We suggest that ultrasonography may be the method of choice for presymptomatic detection of polycystic kidney disease. Serial studies of at-risk individuals by sonography will be useful in determining the earliest age of detection, the latest age of ultrasonography presentation, and in following the natural history of polycystic kidney disease.

Adolescent↗
PubMed1978

Heterozygote expression in propionyl coenzyme A carboxylase deficiency. Differences between major complementation groups.

We measured propionyl coenzyme A carboxylase (PCC) activity in extracts of skin fibroblasts and peripheral blood leukocytes from controls and obligate heterozygotes for PCC deficiency. 6 heterozygotes were from the pcc A complementation group; 12 were from the other major complementation group, designated pcc C. Mean PCC activity in fibroblast extracts from pcc A heterozygotes was 52% of that in controls, whereas mean PCC activity in pcc C heterozygotes was indistinguishable from that of controls. Similar results were obtained with extracts of peripheral blood leukocytes. In none of eight families (three pcc A and five pcc C) in which PCC activity was studied in both parents of an affected child were significant intrafamilial differences observed. The activities of two other mitochondrial enzymes (beta-methyl-crotonyl CoA carboxylase and glutamate dehydrogenase) were comparable in controls and both groups of heterozygotes. Whereas the data from pcc A heterozygotes are consistent with expected gene dosage effects, those from pcc C heterozygotes are not. Inasmuch as mammalian PCC is a large molecular weight tetramer, each protomer of which is probably composed of two nonidentical subunits, the latter results are most consistent with unbalanced rates of synthesis and(or) degradation of the two subunits in normal cells with compensatory balancing in pcc C heterozygotes.

Alleles↗
PubMed1978

Double expression of VH region a2 and a3 allotypes in individual rabbit lymphocytes.

This study provides evidence that two VH region a group allotypic specificities are synthesized by individual peripheral blood lymphocytes from a2,3 rabbits. After removal of both allotypes from the cell surface with pronase, three types of allotype-bearing cells, a2, a3, and a2,3 were demonstrable after overnight culture in serum-free medium. Frequently, greater than 50% of the cells that contained allotype on the surface resynthesized both allotypes. In culture, reappearance of allotype was first detectable at 4 hr and increased progressively thereafter to a maximum at 18 hr. During regrowth, the relative proportion of cells showing both markers was maintained. The predominance of cells exhibiting only a3 over those displaying only a2 was also maintained. Reappearance of allotype was inhibited by cycloheximide but was manifested when the antibiotic was washed out. Monospecific anti-a2 antibodies could completely suppress the resynthesis of homologous allotype in culture and prevent the regeneration of a2 in double-bearing cells. Likewise, anti-a3 in cultures was usually specifically suppressive for a3 allotype; however, the double producers were only partially depleted.

Animals↗
PubMed1978

Regulation of allotype expression in heterozygous rabbits. I. Concomitant modulation of cell surface allotypes on peripheral blood lymphocytes from b4b6 rabbits.

Treatment of b4b6 rabbit peripheral blood lymphocytes with b5b5 anti-b4 antibodies at 4 degrees resulted in the modulation (disappearance) ob b4 and b6 cell surface allotype after subsequent incubation in serum-free medium for 1 h at 37 degrees. A clear dose dependence on the sensitizing anti-b4 antibody was observed. Similarly, b5b5 anti-b6 treatment demonstrated a dose dependence for b6 modulation and a threshold dose effect for b4 comodulation. Cells which formed rosettes with anti-b4-coupled SRBC (anti-b4 direct antiglobulin (DAG) rosettes) also demonstrated concomitant modulation of b4 and b6 allotype when incubated at 37 degrees. When cells formed anti-b6 DAG rosettes, subsequent b6 modulation could also be demonstrated, but no b4 comodulation occurred. Concomitant modulation did not occur when cells were incubated with anti-allotype antibodies at 37 degrees. Blocking studies disclosed that the two allotypes are not contiguous in the membrane since uptake of one antiallotype antibody did not block the uptake of another at 4 degrees. We therefore propose that concomitant modulation might occur during a process similar to patch formation.

Animals↗
PubMed1978

Regulation of allotype expression in heterozygous rabbits. II. Concomitant suppression of b4 and b6 allotypes in the same cell.

Cells from heterozygous b4b6 rabbits were treated at 4 degrees with anti-b4 or anti-b6 antibodies and then warmed at 37 degrees. A disappearance of both b4 and b6 allotypes (concomitant modulation) ensued. When cells which had undergone extensive comodulation were cultured overnight we noted that those cells were unable to re-express either allotype at pre-modulation levels. This suppression was likely linked to the initial events which culminated in comodulation. Those cells were not further suppressible when suppressive antibodies were added to the cultures whereas cell cultures which had undergone little or no previous modulation or comodulation were readily suppressed for both allotypes after anti-allotype antibodies had been added to the cultures overnight (concomitant suppression). This indicated that in vitro suppression of allotype may depend on cell surface allotype being present at a sufficiently high density. We present data which show that events at the cell surface may play a role in the regulation of cell surface allotype expression and propose that concomitant suppression may have bearing on cellular mechanisms which control allotype expression and also allotype suppression.

Animals↗
PubMed1977

Structural transitions of calf thymus DNA in concentrated LiCl solutions.

The solubility, sedimentation, circular dichroism, and absorption spectral characteristics of calf thymus DNA have been examined in concentrated solutions of LiCl (6-13 m) at 25 to 27 degree C. At all concentrations of LiCl, the DNA is base stacked and exhibits normal hypochromicty, At the upper end of this range of LiCl concentrations, DNA aggregates and ultimately precipitates completely from solution between 13 and 14 m LiCl. This aggregation process is dependent on concentration, base composition, and molecular weight of DNA. The sedimentation velocity data taken together with the absorbance spectral data suggest that the aggregation process leading to the formaiton of large structures beings at approximately equal to 9 m. Prior to the onset of aggregation, the circular dichroism (CD) spectra can be adequately fitted by a linear combination of contributions of the B, C, and A forms of DNA (Hanlon, S., Brudno, S., Wu, T. T., and Wolf, B. (1975), Biochemistry 14, 1648). Above 9 m LiCl, both factor analysis and a primitive version of matrix rank order analysis indicate that at least one additional spectral component is required to account for the observed CD spectra above 260 nm. The general shape of this additional component or distortion resembles the psi form of DNA.

Animals↗
PubMed1977

Regulation of allotype expression in heterozygous rabbits. III. Concomitant modulation and concomitant suppression oa a2 and a3 allotypes on individual peripheral blood lymphocytes.

Sensitization of peripheral blood lymphocytes from heterozygous a2/a3 rabbits with purified, monospecific anti-a3 antibodies, raised in a1/a1 rabbits, resulted in the disappearance of surface a2 and a3 allotypes (concomitant modulation) after subsequent incubation at 37 degrees C, as determined by the mixed antiglobulin (rosette) test. Similar results were obtained when anti-a2 antibodies were used. The dose dependence of modulation and comodulation were also studied. Testing of mixtures of homozygous a2/a2 plus a3/a3 cells never led to comodulation. Blocking studies, performed to determine the surface contiguity of a2 and a3 determinants, indicated that both allotypes are situated close together in the membrane on cells exhibiting allotype inclusion. Overnight culture in serum-free medium revealed that cells which underwent extensive modulation and comodulation were often suppressed for both homologous and alternate allotypes (concomitant suppression). These and other data suggest that a single modulation event, in which extensive removal of cell membrane Ig occurred, could serve to inhibit the re-expression of Ig. This may, in part, reflect interactions with membrane receptors involved in the regulation of expression of VH gene products. Implications of VH allotype inclusion are discussed.

Animals↗
PubMed1977

[Quantitative EEG analysis of the effects of carbocromen, pentetrazole, beta-methyldigoxin, and strophantin-K in normal human volunteers (author's transl)].

With EEG-interval analysis we studied the influence on C.N.S. of some drugs normally used for cardiovascular diseases: carbochromen, pentetrazole, beta-methyldigoxin and Strophantin-K. All investigated drugs induced activation of alpha-waves, especially in frontal areas with primary small alpha-activity. Dominant alpha-frequency was accelerated. These results confirm the direct and stimulating effects of these drugs on C.N.S. in therapeutic doses. Alpha-acceleration may not only indicate psychostimulation but also indicate epileptogenic effects. All these drugs may provoke epileptic seizures in toxic doses.

Adult↗