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Biomedical subjects

J G Hall

Publications and source records attributed to J G Hall.

At least 163 records · Page 9Linked to original sources
PubMed1987

Immunity to a syngeneic sarcoma induced in rats by dendritic lymph cells exposed to the tumour either in vivo or in vitro.

Rats were prepared surgically so that peripheral intestinal lymph could be collected from them while a syngeneic tumour (the HSN sarcoma) was growing in each major Peyer's patch of the small intestine. Dendritic lymph cells were isolated from the lymph and injected i.p. into naive, syngeneic rats. Each of the 16 recipients received just under 10(6) such cells and was challenged 10 days later with a subcutaneous dose of 10(4) viable HSN cells. Six weeks after this challenge only 7 of the recipients had a tumour and these were small (mean weight 1.8 g), while 17 controls (which had each been treated with 10(6) thoracic duct lymphocytes from the same donors, and given the same challenge) all had large tumours (mean weight 8.8 g). The remaining 9 test rats were still free of tumours when they were killed and autopsied 4 months after challenge. Dendritic lymph cells from normal rats were 'sensitised' by incubating them overnight on a monolayer of HSN cells. They were then transferred to 5 naive recipients which received the usual challenge. Six weeks later they all had tumours (mean weight 1.3 g) but these were much smaller than those in the 5 controls (mean weight 9.3 g).

Animals↗
PubMed1987

Functional alcohol dehydrogenase mutants of Saccharomyces cerevisiae conferring temperature-conditional allyl alcohol resistance.

Selection for allyl alcohol resistance in respiratory incompetent yeast is a highly specific method for isolating functional mutations at ADH1, the gene coding for the cytoplasmic alcohol dehydrogenase, ADHI. Because of the nature of this selection scheme, the ADHI activity of such mutants is retained, but the kinetic characteristics of the enzymes are altered. The high specificity for targeting functional mutations at this locus suggested that selection for enzyme variants with more subtle phenotypic effects might be possible. Here, we describe functional ADHI mutants that are temperature-conditional in their allyl alcohol resistance. Haploid cells of one of these mutants grow well on plates at 10 mM allyl alcohol at 19 degrees, but not at 37 degrees, the restrictive temperature. A second mutant grows well at 10 mM at 37 degrees, but its growth is restricted at 19 degrees. What distinguishes these mutants from other temperature-sensitive mutants is that the temperature-conditional growth phenotypes described here must be due to interactions between allyl alcohol levels and ADHI functional properties and cannot be due to lability of the enzyme at the restrictive temperature. This system shows promise for the investigation of functional enzyme variants that differ by only one or two amino acid residues but have significant temperature- and substrate-conditional effects on growth phenotypes in both the haploids and the diploids.

1-Propanol↗
PubMed1987

Conditional overdominance at an alcohol dehydrogenase locus in yeast.

Documented examples of heterosis attributable to overdominance at specific protein-encoding gene loci have rarely been reported, the association of sickle cell hemoglobin with malarial resistance being the best documented example of this phenomenon. Here we report an example of overdominance that is temperature- and allyl alcohol-dependent and due to heterozygosity at the ADH1 locus, involving two ADHI functional mutants. Overdominance appears to be due in part to an intermediate level of ADHI activity in the heterozygote. Unlike previous work with this this system using haploid strains, the NAD+/NADH ratios show no negative correlation with allyl alcohol resistance. This system is formally equivalent to that of sickle cell hemoglobin and shows promise as a tool for investigating the physiological basis for overdominance.

Alcohol Dehydrogenase↗
PubMed1987

The functioning in unanaesthetized sheep of the popliteal lymph node after the surgical removal of its blood supply.

Operations were performed to cannulate the efferent duct of the popliteal node of sheep and, at the same time, the blood vascular system was removed surgically from the popliteal fossa so that the node was deprived of it blood supply. Twelve preparations were technically successful in that lymph flowed spontaneously from the unanaesthetised sheep for from 3 to 30 days after the operation. Eight control preparations were established in which the blood supply of the node with the cannulated efferent duct was left intact. In only four of the test preparations was the function of the node decisively impaired so that dendritic macrophages appeared in the lymph, the output of lymphocytes remained very low, and later histological examination showed the nodes to be grossly depleted of lymphocytes. In two of these four preparations the surgical devascularization of the node was aided by arterial embolization. In the remaining eight test preparations the outputs of lymphocytes in the lymph gradually regained normal values, and the nodes then responded normally to antigenic stimuli.

Animals↗
PubMed1986

Familial breast cancer in males. A case report and review of the literature.

The occurrence of breast cancer in two related males, an uncle and nephew is reported. A review of previously reported cases of male breast cancer occurring in families and the association with other cancers in other family members is included. In previous reports on breast cancer in males, familial or hereditary factors have not generally been recognized as a major contributing factor. Of ten families reported (including our own) where there is sufficient information given, six families (60%) had females with breast cancer. It appears there are some families in which males as well as females have an increased risk of developing breast cancer.

Adult↗
PubMed1986

Association of amyoplasia with gastroschisis, bowel atresia, and defects of the muscular layer of the trunk.

We reviewed 225 cases of amyoplasia, and the association of amyoplasia with gastroschisis and with monozygotic twinning was confirmed. In addition, an apparently increased association of bowel atresia and defects in the muscular layer of the trunk wall with amyoplasia was observed. The association of amyoplasia, monozygotic twinning, and these trunk wall defects strongly suggests that the pathogenesis of amyoplasia is linked to some type of vascular compromise.

Abdominal Muscles↗
PubMed1986

Analysis of Pena Shokeir phenotype.

At this point in time, we recognize that "Pena Shokeir" is not a diagnosis or a specific syndrome but rather a description of a phenotype produced by fetal akinesia or decreased in utero movement. In its "full blown" form, it is characterized by polyhydramnios, intrauterine growth retardation, pulmonary hypoplasia, craniofacial and limb anomalies, congenital contractures, short umbilical cord, and lethality. From the cases thus far reported, we would anticipate that the phenotype is present in a very heterogeneous group of disorders--heterogeneous both with regard to the specific anomalies present and with regard to the causes (which must include many environmental agents and multiple genetic forms). One challenge for the future is to better describe and delineate specific entities. In the meantime, we would do well to use the terms "Pena Shokeir phenotype" or "fetal akinesia/hypokinesia sequence," which do not imply a single entity. There are many practical aspects of recognizing this phenotype. The presence of any one of the cardinal signs of the fetal akinesia/hypokinesia sequence should alert the physician to look for the other associated anomalies, since specific treatment may be indicated, and catch-up or compensatory growth may occur, if given a chance. The ability to provide prenatal diagnosis and perhaps prenatal treatment in the future may allow us to alter dramatically the natural history of some cases. In others, we need to establish when treatment is possible and when it gives no benefit. Perhaps the most important insight gained from the study of the fetal akinesia sequence is the reaffirmation of the concept that function is an integral part of normal development. Specific structures do not develop in isolation but are part of a carefully timed and integrated system. The "use" of a structure in utero is necessary for its continuing and normal development. The old adage "use it or lose it" seems to apply just as appropriately to prenatal normal development as it does in the crusty adult world of politics, business, and academia.

Abnormalities, Multiple↗
PubMed1986

Risks to sibs of probands with neural tube defects: data for clinic populations in British Columbia.

The purpose of this study is to determine whether couples receiving genetic counselling because of a child with a neural tube defect (NTD) are a selected group and therefore not representative of the general population with respect to sib risks for NTDs. British Columbia (B.C.) provides an excellent opportunity to look at this for several reasons. Firstly, genetic counselling services are centralized. Secondly, there is virtually complete ascertainment of all infants with NTDs in the province. Thirdly, sib risks for NTDs in the general population have been derived previously [McBride, 1979] and, therefore, are available for comparison with the risks for sibships in the clinic populations. In the present study, data were available on 398 sibships in which the index case had anencephaly and/or spina bifida. In all instances, sib risks for the clinic populations did not differ significantly from those for the general population. In addition, congenital malformations other than NTDs did not occur among sibs of index cases more often than expected, based on provincial incidence data.

Anencephaly↗
PubMed1986

Studies of human achondroplasia: oxidative metabolism in tissue culture cells.

Mitochondria prepared from the first growth of cells (fibroblasts) from skin biopsies from homozygous (but not heterozygous) achondroplastic human subjects were unable to carry out oxidative phosphorylation. However, successive crops of cells gained the ability to phosphorylate with normal P:O ratios with pyruvate-malate and succinate as substrates. Concentrations of cytochromes a + a3 were markedly and significantly lower in homogenates of homozygous achondroplastic tissue culture cells than in homogenates of normal cells. Levels of cytochromes a + a3 in the heterozygous achondroplastic cells were intermediate between the levels in normal cells and the homozygous achondroplastic cells. Activities of the mitochondrial oxidative systems (NADH, succinic and cytochrome oxidases) were not significantly lower in the achondroplastic cell preparations than in normal cell preparations under standard assay conditions (saturation levels of oxygen).

Achondroplasia↗