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Biomedical subjects

J Hopkins

Publications and source records attributed to J Hopkins.

At least 217 records · Page 12Linked to original sources
PubMed1977

Phenacetin and analgesic nephropathy.

A prospective survey of 322 autopsies of adults conducted some months after phenacetin was removed from a popular compound analgesic showed to reduction in the incidence of advanced or earlier forms of analgesic nephropathy from levels noted in an earlier survey. Apparently active nephropathy was seen in persons taking two different compound analgesics, neither now containing phenacetin. Crystals observed in early and intermediate analgesic nephropathy had no diagnostic significance and represented a tissue breakdown product.

Adult↗
PubMed1977

Studies on the lymphocytes of sheep. III. Destination of lymph-borne immunoblasts in relation to their tissue of origin.

Lymph-borne immunoblasts were labeled in vitro with 125I[]iodo-deoxy-uridine, washed and returned by intravenous injection to the sheep from which they had been collected. Twenty h later the sheep were killed and the distribution of the immunoblasts was determined by assaying the radioactivity in various organs. Immunoblasts from the efferent lymph of peripheral somatic lymph nodes (PSLN) went mainly to the spleen, lungs and other PSLN, while immunoblasts from intestinal lymph went mainly to the small gut. This ability of intestinal immunoblasts to home to the gut was demonstrated also in the sterile environment of fetuses in utero; apparently the migratory behavior of immunoblasts, like that of small lymphocytes, is not primarily "antigen-driven". A technique was devised for the collection of peripheral (i.e. afferent to the mesenteric node) intestinal lymph which was found to contain 10-20 times the numbers of small lymphocytes that occur in the peripheral lymph from other tissues. Immunoblasts from peripheral intestinal lymph also homed to the gut. The immunoglobulin content of immunoblasts was studied by making detergent extracts of lymph cells, by applying immuno-peroxidase techniques to cell films and by investigating the incorporation of 14C-labeled amino acids into immunoglobulins by immunoblasts in vitro. Immunoblasts from both somatic and intestinal lymph contained and made IgG and IgM, but many intestinal immunoblasts contained and made IgA. It is not known whether this immunoglobulin mediates the extravasation of immunoblasts into the gut. Nonetheless, there is compelling evidence that there are two major migratory pathways for lymphoid cells; one through the gut-associated lymphoid tissue and the other through the somatic-splenic lymphoid tissues.

Animals↗
PubMed1977

Indium-111-labeled cellular blood components: mechanism of labeling and intracellular location in human neutrophils.

Human neutrophils were labeled with In-111 oxine by incubation at room temperature, and the fate of the oxine and the intracellular location of the In-111 were determined. Neutral (1:3) In-111 oxine complex diffuses rapidly across the cell membrane and then dissociates. Some of the oxine leaves the cell and the In-111 binds intracellularly. After short periods of incubation the label is distributed mostly to four soluble components, a small proportion of which had a distribution similar to that of specific and azurophil granules. After longer incubation periods there was relatively less radioactivity with the soluble components and probably more attached to the particulate material. A small peak of radioactivity also appeared in the region of DNA distribution, but no confirmation could be obtained for the association of the In-111 radioactivity with DNA.

Centrifugation, Isopycnic↗
PubMed1976

Human oral defenses against gram-negative rods.

Gram-negative rods are unusual pharyngeal isolates in normal man, which suggests the presence of effective oral defense mechanisms against these organisms. To understand this protection better, we studied the elimination of gram-negative rods from the mouth after gargle challenge. Suspensions of Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis (108 organisms per ml) were gargled by normal volunteers, and pharyngeal swabs for serial quantitative cultures were taken for 3 hours. Initial swabs yielded approximately 10(5) organisms. Bacterial counts rapidly decreased, and less than 1 per cent of the original inoculum was still recoverable 3 hours later. Studies of tongue, pharynx, and buccal mucosa samples showed the most rapid decrease in buccal mucosa samples and the slowest decrease in tongue swabs. To evaluate physical clearance, gargle challenges were performed using E. coli radiolabeled with technetium-99m. External counts of the oral cavity decreased rapidly, with 21.8, 14.7, 8.9, and 7.8 percent of the initial counts remaining at 30, 60, 120, and 180 min, respectively. Nonpiliated E. coli adhered poorly to buccal epithelial cells in vitro, in contrast to good adherence when piliated strains were tested. Despite these findings, no differences in radiolabel clearance was noted in vivo using piliated and nonpiliated E. coli for gargle challenges. Normal oral defenses against gram-negative rods are highly effective and seem to involve both physical clearance and local bactericidal activity.

Adult↗
PubMed1975

Lipid peroxidation in human erythrocytes in tocopherol deficiency.

Lipid peroxidation following exposure to H2O2 vapour was abnormally great in the erythrocytes from certain patients with low plasma tocopherol concentrations. Following treatment of such patients with tocopherol, erythrocyte lipid peroxidation was markedly reduced. The in vitro addition of tocopherol reduced lipid peroxidation in erythrocytes from both normal subjects and tocopherol-deficient patients.

Aged↗