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Biomedical subjects

B D Hall

Publications and source records attributed to B D Hall.

At least 181 records · Page 10Linked to original sources
PubMed1976

Prenatal diagnosis of congenital anomalies in an intrauterine growth retarded fetus.

Chromosome analysis of amniotic fluid cells and amniotic fluid alpha-fetoprotein determinations were used to investigate a fetus with severe intrauterine growth retardation in the third trimester. The karyotype was 47,XY,18+ and increased alpha-fetoprotein levels indicated the presence of congenital malformations. We suggest that when severe fetal growth retardation is detected early in the antepartum course, amniotic fluid alpha-fetoprotein and amniotic fluid cell chromosome studies be done to determine if congenital anomalies may be an etiological factor.

Abnormalities, Multiple↗
PubMed1976

A yeast mutant defective in the processing of 27S r-RNA precursor.

Among a group of 31 ts- yeast mutants screened electrophoretically for heat-sensitive synthesis of each stable RNA species, only mutant ts351 failed to accumulate 25S RNA at 36 degrees C. Pulse-labeling experiments at 36 degrees C showed that 35S and 27S precursors RNA and mature 18S r-RNA molecules are synthetized by ts351 cells but that 25S and 5.8S RNA species are not made and new 60S ribosomal sub-units are not assembled. The mutant is blocked at a specific point in r-RNA processing: the cutting of 27S to form 25S and 5.8S r-RNA.

Electrophoresis, Polyacrylamide Gel↗
PubMed1976

Transcription in yeast: alpha-amanitin sensitivity and other properties which distinguish between RNA polymerases I and III.

Three peaks of DNA-dependent RNA polymerase (RNA nucleotidyltransferase) activity are resolved by chromatography of a sonicated yeast cell extract on DEAE-Sephadex. The enzymes, which are named RNA polymerases I, II, and III in order of elution, show similar catalytic properties to the vertebrate class I, class II, and class III RNA polymerases, respectively. Yeast RNA polymerase III is readily distinguished from yeast polymerase I by its biphasic amnonium sulfate activation profile with native DNA templates, greater enzymatic activity with poly[d(I-C)] than with native salmon sperm DNA, and distinctive chromatographic elution positions from DEAE-cellulose (0.12 M ammonium sulfate) compared with DEAE-Sephadex (0.32 M ammonium sulfate). The three yeast RNA polymerases also show significant differences in alpha-amanitin inhibition. RNA polymerase II is the most sensitive (50% inhibition at 1.0 mug of alpha-amanitin per ml). Contrary to the results for vertebrate systems, yeast polymerase I can be completely inhibited by alpha-amanitin at high concentrations (50% inhibition at 600 mug/ml) while yeast RNA polymerase II BEGINS TO SHOW SIGNIFICANT INHIBITION ONLY AT CONCENTRATIONS EXCEEDING 1 MG/ML. Therefore, yeast RNA polymerases I and III show a pattern of alpha-amanitin sensitivity that is the reverse of that seen for the analogous vertebrate RNA polymerases.

Amanitins↗
PubMed1976

Tetraploidy in a liveborn infant.

A congenitally malformed infant with a tetraploid chromosome complement who survived to 1 year of age is reported. The relationship of the polyploidy and the anomalies is discussed.

Abnormalities, Multiple↗
PubMed1975

Macrocephaly in association with unusual cutaneous angiomatosis.

Ten patients are presented who demonstrate a newly recognized association of macrocephaly with unusual angiomatosis and limb asymmetry in three somewhat similar cutaneous vascular disorders: Klippel-Trenaunay-Weber syndrome, the combination of Sturge-Weber anomaly with Klippel-Trenaunay-Weber syndrome, and cutis marmorata telangiectatica congenita. The etiology of the macrocephaly in patients with these conditions is unknown. The majority (seven of ten) of these children have no evidence of central nervous system dysfunction.

Angiomatosis↗
PubMed1975

Older paternal age and fresh gene mutation: data on additional disorders.

Older paternal age has previously been documented as a factor in sporadic fresh mutational cases of several autosomal dominant disorders. In this collaborative study, an older mean paternal age has been documented in sporadic cases of at least five additional dominantly inheritable disorders; the basal cell nevus syndrome, the Waardenburg syndrome, the Crouzon syndrome, the oculo-dental-digital sysdrome, and the Treacher-Collins syndrome. It was also found to be a factor in acrodysostosis and progeria, suggesting a fresh mutant gene etiology for these two conditions in which virtually all cases have been sporadic and the mode of genetic etiology has been unknown.

Age Factors↗
PubMed1975

Mating type and sporulation in yeast. I. Mutations which alter mating-type control over sporulation.

In Saccharomyces cerevisiae, meiosis and spore formation as well as mating are controlled by mating-type genes. Diploids heterozygous for mating type (aalpha) can sporulate but cannot mate; homozygous aa and alpha-alpha diploids can mate, but cannot sporulate. From an alpha-alpha diploid parental strain, we have isolated mutants which have gained the ability to sporulate. Those mutants which continue to mate as alpha-alpha cells have been designated CSP (control of sporulation). Upon sporulation, CSP mutants yield asci containing 4alpha spores. The mutant gene which allows alpha-alpha cells to sporulate is unlinked to the mating-type locus and also acts to permit sporulation in aa diploid cells. Segregation data from crosses between mutant alpha-alpha and wild-type aa diploids and vice versa indicate (for all but one mutant) that the mutation which allows constitutive sporulation (CSP) is dominant over the wild-type allele. Some of the CSP mutants are temperature-sensitive, sporulating at 32 degrees, but not at 23 degrees. In addition to CSP mutants, our mutagenesis and screening procedure led to the isolation of mutants which sporulate by virtue of a change in the mating-type locus itself, resulting in loss of ability to mate.

Cell Nucleus↗
PubMed1975

Mating type and sporulation in yeast. II. Meiosis, recombination, and radiation sensitivity in an alpha-alpha diploid with altered sporulation control.

In wild-type S. cerevisiae, diploid cells must be heterozygous at the mating-type locus in order to sporulate. In the preceding paper, we described a number of mutants (CSP mutants), isolated from nonsporulating aa and alpha-alpha parent strains, in which sporulation appeared to be uncoupled from control by mating type. The characterization of one of these mutants (CSP1) is now extended to other processes controlled by mating type. This mutant is indistinguishable from alpha-alpha cells and unlike aalpha cells for mating factor production and response, zygote formation, intragenic mitotic recombination, and for X-ray sensitivity. The mutant apparently undergoes a full round of DNA synthesis in sporulation medium, but with delayed kinetics. Only 20% of the cells complete sporulation. Among spores in completed asci, the frequency of both intra- and intergenic recombination is the same as it is for spores produced by aalpha cells. However, experiments in which cells were shifted from sporulation medium back to minimal growth medium gave a frequency of meiotic recombination between ade2 or leu2 heteroalleles only 25% to 29% as high for CSP1 alpha-alpha diploid or CSP1 aa disomic cells as for aalpha diploid or disomic cells. Because the latter result, indicating recombination defectiveness, measured recombinant production in the entire cell population, whereas the result indicating normal recombination sampled only completed spores, we infer that all meiotic recombination events occuring in the population of CSP1 alpha-alpha cells are concentrated in those few cells which complete sporulation. This high degree of correlation between meiotic recombination and the completion of meiosis and sporulation suggests that recombination may be required for proper meiotic chromosome segregation in yeast just as it appears to be in maize and in Drosophila.

Alleles↗
PubMed1975

Mutation of a heterothallic strain to homothallism.

Upon mutagenesis, a heterothallic alpha-alpha diploit strain mutated to homothallism. The gene confering homothallism is nuclear, recessive, and unlinked to mating type. This gene is not allelic to the HO gene, which is responsible for previously described instances of homothallism in yeast. We have designated this new gene for homothallism as cmt (change of mating type).

Alleles↗
PubMed1975

The center-satellite system for the wide-scale distribution of genetic counseling services.

A 6-year experience with a center-satellite system for the provision of comprehensive genetic counseling services to a large geographical area is described. A series of 12 satellite genetic clinics established throughout northern and central California have brought genetic counseling services to within a 2-hour drive for most patients. These satellite clinics are largely organized by local groups (such as National Foundation-March of Dimes chapters and county health departments) but are backed by the personnel and resources of the center at the University of California, San Francisco. Assistance is generally provided by county public health nurses who collect medical records from referring physicians and pedigrees from the family. Specimens for cytogenetic or special biochemical studies are brought back to the center, but, if possible, other laboratory determinations, radiological investigations, and specialty consultations are obtained locally. Follow-up counseling may be provided by the public health nurses, and a written summary is sent to each patient or family. The socioeconomic spectrum of the patients seen at the satellite clinics is much broader than at the central clinic, and the establishment of a satellite clinic results in a great increase in the number of cases seen from the area in which it is located. Physician time per patient and cost of services per patient are substantially the same in both central and satellite clinics. Based on population figures applicable to the state of California, it is estimated that approximately 60-70 comprehensive counseling centers, each with up to 15 satellites, could adequately provide for the foreseeable genetic counseling needs of the United States.

Ambulatory Care Facilities↗
PubMed1974

A pattern of craniofacial and limb defects secondary to aberrant tissue bands.

Seven infants have been studied who have a similar pattern of severe craniofacial and limb anomalies associated with aberrant tissue bands. The craniofacial anomalies consist of unusual encephaloceles, facial clefts, and cranial plus midfacial distortion; the limb anomalies consist of constrictions, amputations, and pseudosyndactyly. These defects are interpreted as being secondary to the early distorting and disruptive effects of aberrant tissue bands, the etiology for which is undetermined. Survival beyond the neonatal period has occurred in four of the five liveborn patients, indicating that early death should not necessarily be anticipated. Recurrence risk is apparently negligible.

Abnormalities, Multiple↗