Notes of a biology-watcher the hazards of science.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to L Thomas.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A newly developed artificial pancreatic beta cell is described and its use in five children with diabetes mellitus is evaluated. This device can be programmed to bring the blood glucose concentration rapidly to a preselected level and normalize glucose tolerance in juvenile diabetic patients with markedly different insulin requirements. It is portable, can be operated by one person, and has been used to regulate the blood glucose concentration before, during, and after surgery requiring general anesthesia. The potential value of the device as an investigational tool is shown by demonstrating that regulation of the blood glucose concentration with insulin for seven to 24 hours does not alter circulating glucagon concentrations in the juvenile diabetic patients studied.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Spleen cells from C3H/HeJ mice are known to be unresponsive to mitogenic stimulation by LPS. We show here that T and B cell precursors of C3H/HeJ mice are unresponsive to induction of differentiation by LPS. Phenotypic differentiation of C3H/HeJ lymphocytes can be induced with DB-cAMP, Lipid A-associated protein, and with a serum factor induced by LPS in LPS responder strains.
The present-day technique of determining the concentration of aminoglycosides in blood by agar diffusion is described including the apparatuses, set-up, and reliability tests. The results of comparative investigations showed a higher degree of conformity in Mueller-Hinton agar than in standard agar. Due to its accuracy the agar diffusion method is especially suited for the calculation of dosage recommendations and for the prediction of the maximal and minimal blood levels during treatment with aminoglycosides.
Explore the source record for details and available documents.
When a male mouse is presented with two H-2 congenic two female in estrus, his choice of a mate is influenced by their H-2 types. The term "strain preference" is used to describe the general tendency of the male population of one inbred strain to prefer two female of one H-2 type rather than another. The term "consistency of choice" is used to describe the added tendency of particular two males of one inbred strain, in sequential mating trials, to prefer two females of the H-2 type they chose in previous trials. Statistical analysis showed trends in the data that support the following conclusions: (a) The choice is made by the male, not the female. (b) The strain preference of two males may favor two females of dissimilar H-2 type (four of six comparisons), or of similar H-2 type (one of six comparisons). (c) Consistency of choice does not always correspond with strain preference. In one of six comparisons of H-2 genotypes there was no strain preference but pronounced consistency of choice by individual two male. This suggests memory, but fortuitous bias is not excluded. (d) Strain preference of the same male population may favor two male of the same or a different H-2 type, depending on which different H-2 type is offered as the choice alternative to self. These findings conform to a provisional model in which olfactory mating preference is governed by two linked genes in the region of H-2, one for the female signal and one for the male receptor. These mating preferences could in natural populations serve the purpose of increasing the representation of particular H-2 haplotypes or of maintaining heterozygosity of genes in the region of H-2.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
During epidemiologic studies of Rocky Mountain Spotted Fever in Mississippi in 1973, dogs were surveyed for antibodies tp spotted fever group antigens and for tick parasites infected with rickettsiae of the spotted fever group. Fifty-three (46%) of 116 serum samples had complement-fixing antibody titers greater than or equal to 1:8 as compared to only one (5%) of 21 samples from a group of dogs obtained from metropolitan Chicage. Fifty-two per cent of the dogs tested from Mississippi had microagglutinating antibodies titers greater than or equal to 1:8; 9% of dogs from Chicago had similar titers. Rickettsia rickettsii was demonstrated in only one (0.8%) of 129 Dermacentor variabilis removed from Mississippi dogs. Quite unexpectedly, 167 (18.9%) of 884 Rhipicephalus sanguineus taken from these dogs contained spotted fever group rickettsiae.
Explore the source record for details and available documents.
Although polyvinyl chloride has been produced from vinyl chlride monomer for more than 40 years, recognition of toxicity among vinyl chloride polymerization workers is more recent. In the mid 1960s, workers involved in cleaning polymerization tanks were found to have acro-osteolysis. In 1974, the same population of workers was found to be at risk for an unusual type of hepatic fibrosis and angiosarcoma of the liver. We describe two cases of vinyl chloride-associated liver injury, one of hepatic fibrosis and one of angiosarcoma. Histologic features of these lesions are similar to the hepatic fibrosis and angiosarcomas resulting from chronic exposure to inorganic arsenicals. Preliminary studies suggest that the toxicity of vinyl chloride may result from formation, during high-dose exposure, of active metabolites by mixed function oxidases of the liver. Epidemiologic studies indicate an increased incidence not only of liver disease, but also of cancers of the brain, lung, and possibly other organs.
Explore the source record for details and available documents.