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Biomedical subjects

C A Hall

Publications and source records attributed to C A Hall.

At least 73 records · Page 4Linked to original sources
PubMed1983

Hydrophobic interactions of transcobalamin II (TC II) from mammalian sera.

The hydrophobic properties of mammalian transcobalamin IIs (TC II) were studied by chromatography of radioactive cyanocobalamin (CN[57Co]Cbl)-labeled serum on phenyl-Sepharose CL-4B. Mammalian holo TC IIs (CN[57Co]Cbl-TC II) exhibited species variability in their affinity for the hydrophobic matrix in the order: dog greater than mouse greater than human greater than rat greater than rabbit. Phenyl-Sepharose chromatography of the isolated CN[57Co]Cbl-TC II peaks from gel filtration of dog and rat serum showed no hydrophobic change in dog TC II, but an increase in hydrophobicity of rat TC II. Phenyl-Sepharose chromatography of CN[57Co]Cbl-labeled rabbit serum (holo TC II) and the unlabeled serum (apo TC II) showed apo TC II to be more hydrophobic than holo TC II as has been shown for human TC II (Begley et al., Biochem Biophys Res Commun 103:434-441, 1981). Thus mammalian holo TC IIs differ in their hydrophobic properties and apo TC II, in man and rabbit, is more hydrophobic than holo TC II. In addition, isolation of the TC II in some animal sera by gel filtration may result in a TC II that is more hydrophobic than the native molecule.

Animals↗
PubMed1983

Changes in resistance in mixed infections of susceptible and benzimidazole resistant strains of Haemonchus contortus and Trichostrongylus colubriformis passaged in sheep.

Benzimidazole resistant strains of Haemonchus contortus and Trichostrongylus colubriformis were each diluted with equal numbers of their respective susceptible genotypes and passaged in separate worm-free sheep. The progeny of the mixed susceptible and resistant infections were diluted with equal numbers of susceptible genotypes before passaging on two further consecutive occasions in worm-free sheep. In H contortus the amount of thiabendazole required to prevent a 50 per cent egg hatching (LC50) was reduced at each generation, but the reduction was significant (P less than 0.05) only at the third passage. In T colubriformis the LC50 for thiabendazole was reduced only at the first passage and thereafter remained constant. The reduction was not significant. In another experiment, the dilution with susceptible genotypes was made only at the first passage. Thereafter for two further generations the progeny produced from the mixed infection were passaged in worm-free sheep. In H contortus a reduced amount of thiabendazole was required to prevent a 50 per cent egg hatching at each generation, but did not reach a level of significance. The result for T colubriformis was identical to the continuous dilution experiment.

Animals↗
PubMed1982

Interaction of microwave radiation with turkey sperm.

Turkey sperm were exposed to 2.45 GHz microwave radiation in a temperature controlled waveguide apparatus. Temperature was maintained at 40.0 +/- 0.5 degrees C. The sperm were exposed for 30 min to a specific absorption rate (SAR) of 1, 10, or 50 mW/g. Before and following microwave exposure the following parameters were examined: percentage viability, percentage abnormal sperm, and release of the enzymes lactate hydrogenase (LDH) and glutamic oxalic transaminase (GOT). These parameters were not altered significantly by microwave exposure under the conditions tested.

Animals↗
PubMed1982

Atypical cobalamin binding in the serum of congenital deficiency of transcobalamin II.

The serum cobalamin (Cb 1) binding patterns were described in nine children with congenital deficiency of transcobalamin II (TC II). Immunoreactive TC II was less than 100 pg/ml TC II-Cb 1 equivalent in eight and 150 pg/ml in the ninth. There was neither endogenous TC II-Cb 1 (holo TC II) nor apo TC II. Thus, the defect was characterized by the absence of any binding of Cb 1 to TC II either in vivo or in vitro and either non-detectable or much reduced immunoreactive TC II. Only the serum from an untreated infant bound any added Cb 1 at all, but in every sera there was binding of endogenous Cb 1 to a substance of the molecular size of albumin. Native Cb 1 was also bound to R binder and in some instances was incorporated into large complexes. The precise nature, cause and consequences of this atypical binding are unknown.

Adolescent↗
PubMed1981

Vitamin B12 deficiency and early rise in mean corpuscular volume.

An increase in the mean corpuscular volume (MCV), while not diagnostic of vitamin B12 or folate deficiency, is a valuable, readily available screening test. I discuss six instances where an increased MCV was recorded months prior to diagnosis and could, if noted, have led to an earlier diagnosis.

Aged↗
PubMed1981

Humoral and cell-mediated immune function in adult Japanese Quail following exposure to 2.45-GHz microwave radiation during embryogeny.

Japanese quail, Coturnix coturnix japonica, eggs were subjected to 2.45-GHz CW microwave radiation at 5 mW/cm2 (SAR = 4.03 mW/g) during the first 12 days of embryogeny. Following hatching the exposed embryos, as well as nonexposed controls, were reared to 22 weeks of age. Humoral immune potential, as indicated by comparable anti-CRBC antibody, IgM and IgG, levels at 0, 4, and 7 days postimmunization in both exposed and control quail was not affected significantly. However, cell-mediated immune potential, measured by the reaction to intradermal injection of phytohemagglutinin-P in the wing web, was reduced in the exposed females, but not in the exposed males. Additionally, total leukocyte numbers and absolute circulating numbers of lymphocytes, monocytes, and heterophils were increased significantly only in the exposed females. These data show that exposure of Japanese quail during embryogenesis reduced cell mediated immune potential and induced a general leukocytosis in females.

Animals↗
PubMed1981

The content, binding, and forms of vitamin B12 in milk.

The vitamin B12 (cobalamin, Cbl) content of 19 human milks ranged from 0.33 to 3.20 ng/ml, mean 0.97 ng/ml. The milk content of 10 mothers taking 5 to 100 micrograms of supplemental cyanocobalamin daily was not significantly different from that of unsupplemented mothers. The Cbl native to milk was bound to an R type binder. The R binder was also the dominant, by far, unsaturated Cbl binder, but transcobalamin II was found in every milk. The amounts of transcobalamin II were of the same order of magnitude as in serum and seemed to increase with the interval postpartum. Methylcobalamin was the most abundant Cbl of milk. Human milk from well fed mothers contains adequate amounts of Cbl, but the Cbl may become available only if there are sufficient proteolytic enzymes to release it from binding to R binder.

Chromatography, Gel↗
PubMed1981

Antibody response to pneumococcal vaccine in patients with multiple myeloma.

Patients with multiple myeloma and Waldenström's macroglobulinemia respond poorly to antigenic stimuli and may not be protected by pneumococcal vaccine. Thirty-seven patients and 10 controls received 14-valent pneumococcal capsular polysaccharide vaccine. The patients had lower (P less than 0.01) titers of antibody to 11 of the 12 antigens assayed before vaccination and to 10 of 12 antigens (P less than 0.01) after vaccination than did controls, but the ratios of antibody titers before vaccination to those after vaccination were remarkably similar. A poorer antibody response was observed in patients receiving multiagent chemotherapy than in those receiving chemotherapy with alkylating agents (P less than 0.01 for six of the antigens). That these patients did respond to the vaccine (although titers of antibody after vaccination were significantly lower than those in controls) suggests that patients with multiple myeloma or macroglobulinemia may benefit from pneumococcal vaccine.

Aged↗
PubMed1981

Forms of vitamin B12 in radioisotope dilution assays.

Since the presence of analogues of vitamin B12 (B12, cobalamin, Cbl) has been postulated as the basis for the high values obtained by some radioisotope dilution assays (RIDA) of serum Cbl we examined serum for analogues. None could be demonstrated in the extracts of serum prepared for RIDA as sought by both direct and indirect techniques. The natural forms of serum Cbl were converted to cyanocobalamin (CN Cbl) by this process of extraction which included cyanide (CN). The correctly performed RIDA for Cbl based on R binder gave higher values than a RIDA based on intrinsic factor or than by bioassay. By exclusion, the difference appeared to be due to unidentified factors rather than the presence of analogues.

Chromatography, Gel↗
PubMed1981

Investigations for anthelmintic resistance in gastrointestinal nematodes from goats.

Field results from a commercial goat herd, based on egg counts and larval differentiation, suggested that anthelmintic resistance was present to albendazole, fenbendazole, levamisole, morantel, naphthalophos and phenothiazine. When the isolate was tested in sheep, using levamisole or oxfendazole, a possible resistance was shown for Trichostrongylus sp but no resistance was demonstrated in Haemonchus or Ostertagia spp. Ivermectin at a dose rate of 100 micrograms/kg was more than 98 per cent efficient in removing the adults of each of the three species of nematode. The phenomenon relating to the influence of the host on anthelmintic resistance is discussed.

Animals↗