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Biomedical subjects

H Friedman

Publications and source records attributed to H Friedman.

At least 415 records · Page 23Linked to original sources
PubMed1978

Long-term effects of LSD-25 on easy and hard visual discrimination in rats.

Rats subjected either to unilateral frontal cortex lesion or sham operation were trained to discriminate between a lighted and unlit alley to escape to shock. After reaching criterion, the rats were intubated with either placebo or LSD-25 (1.0 mg/kg). One week or 1 month later they were given discrimination trials with either an increased (hard) level of task difficulty, or with the same (easy) level used in pre-intubation training. A single-dose effect, as long as 1 month post-intubation, was observed both in error scores and running time, but only with hard discriminations. The study emphasizes the sensitivity of the experimental paradigm which reduces the risk of Type II error.

Animals↗
PubMed1978

Histochemical study of labial salivary glands in Sjögren's syndrome.

Human labial salivary gland biopsies of patients presenting connective tissue diseases associated with Sjögren's syndrome were submitted to a polysaccharide histochemistry study. The normal acinar secretion is an association of neutral polysaccharides with a sulphosialomucin. In Sjögren's syndrome, there is a great reduction in the secretory activity of the acinar cells, but no qualitative change was observed. The pathogenesis of this decreased production and its importance regarding the clinical manifestations of Sjögren's syndrome are discussed.

Atrophy↗
PubMed1978

Role for macrophages and thymus-derived lymphocytes in cholera toxin-induced immunosuppression.

The exo-enterotoxin derived from Vibrio cholerae bacilli has marked immunomodulating activities, both in vivo and in vitro. In the present study, the mechanism whereby cholera toxin depresses the antibody-forming ability of murine splenocytes was investigated by in vitro reconstitution experiments. Spleen cells derived from mice treated with cholera toxin 2 days earlier were markedly deficient in their ability to respond to sheep erythrocytes upon challenge immunization in vitro. Addition of graded numbers of normal spleen cells to spleen cell cultures from toxin-treated mice partially restored the antibody response. Adherent splenocyte populations were even more effective in restoring antibody formation. Normal peritoneal exudate cells rich in macrophages were also capable of restoring the antibody-forming ability of toxin-pretreated splenocytes. Furthermore, thymus (T)-derived spleen cells from normal mice, as well as sheep erythrocyte "educated" T cells, were capable of restoring antibody formation to normal levels. The importance of T lymphocytes in restoring immune competence of spleen cell cultures from toxin-treated mice was shown by additional experiments in which T-depleted cell preparations were found to be ineffective in restoring antibody activity. These studies point to macrophages and T-derived lymphocytes as a major target for cholera toxin-induced immunosuppression.

Animals↗
PubMed1978

Scanning electron microscopy of lymphoid cells from leukemia virus-infected mice.

Spleen, lymph node, bone marrow, and thymus cells from Friend leukemia virus (FLV)-infected mice were examined by scanning electron microscopy. Whereas splenocytes from normal, noninfected animals showed the expected morphological classes of lymphocytes, including cells with numerous villous projections and smoother cell types, spleen cells from mice infected with FLV showed a rapid alteration of surface morphology. Shortly after infection, a decrease in the number and percentage of villous cells occurred, with a concomitant increase in the number of cells that were larger and smoother. Within 10 to 20 days after infection, the majority of splenocytes were smooth, large cells showing many distinct morphological charges, including surface "holes" and a "spongy" appearance. By days 25 to 35 after infection, most splenocytes were abnormal in appearance. Similar changes occurred in the lymph nodes after FLV infection, but the rate of change was much lower. Abnormal and larger smooth-surfaced cells did not become prominent until after week 2 or 3 infection. Thymus and bone marrow cells showed little if any change in surface morphology until late in the infectious process. However, even at that time only a few of the cells were abnormal in appearance. The changes in cell population in the spleen but not the lymph nodes paralleled the rapid decrease in the percentage of cells which stained positive for surface immunoglobulin and theta antigen. Futhermore, FLV antigen rapidly appeared on spleen cells after infection; fewer lymph node cells were positive, and only low numbers of marrow and thymus cells stained positive for FLV antigen. The marked immunosuppression induced by FLV infection paralleled and in some instances preceded the marked morphological changes.

Animals↗
PubMed1978

L-Arabinose-ornithine-Irgasan medium for differentiating Serratia species.

A semisolid medium (designated Serratia differentiation medium) containing L-arabinose, ornithine, and selective inhibitor was used to differentiate three clinically encountered Serratia species. The inhibitor, Irgasan DP-300, was incorporated to eliminate false-positive reactions from most remaining Enterobacteriaceae. The suspected Serratia colony was inoculated as a stab into the medium. Serratia marcescens was indicated by a change in color from olive to purple following 18 h of incubation, whereas S. rubidaea (not listed in Bergey's Manual of Determinative Bacteriology) was indicated by a change to bright yellow. S. liquefaciens (described in Bergey's Manual of Determinative Bacteriology [8th ed., 1974] as Enterobacter liquefaciens) produced a small purple band at the top of the medium and a yellow or yellow-green butt. Absence of growth and color change following incubation indicates that the suspected colony is a non-Serratia. Thirty-six Serratia strains and 97 other Enterobacteriaceae and Pseudomonadaceae strains were tested. Two strains of the non-Serratia Enterobacteriaceae (one each of Citrobacter freundii and Proteus morganii) and two strains of Pseudomonas aeruginosa produced a color change in the medium. All of the Serratia strains tested were correctly identified using this medium, while 96% of the other species tested were inhibited.

Arabinose↗
PubMed1978

Comparison of a radiometric procedure with conventional methods for identification of Neisseria.

A radiometric procedure was compared with the conventional cystine tryptic agar (CTA) sugar fermentation method for identification of Neisseria species. Four different ATCC cultures of Neisseria were identified by both procedures with identical results. The only difference noted was that the radiometric procedure required 3 h for completion, whereas the conventional CTA sugar method required overnight incubation. The radiometric procedure was also compared with the fluorescent antibody (FA) and CTA methods for identification of Neisseria gonorrhoeae. The organisms examined were gram-negative, oxidase-positive diplococci isolated from 49 clinical specimens sent to the laboratory for bacteriological analysis. Results obtained by both CTA and FA procedures were comparable. However, the radioisotope method appeared to be superior to the other two methods in that only one isolate identified as positive by both the CTA and FA methods was not identified radiometrically, whereas four isolates positive by the radiometric method were not identified by the other two procedures. Thus, a total of seven more positive identifications were made radiometrically than by either of the two other methods. All positive identifications were confirmed by a reference laboratory. These results indicate that the radiometric procedure is more rapid and reliable as compared with both the CTA and direct FA methods and, thus, may serve as a valuable addition to the methodology available for diagnostic microbiology.

Bacteriological Techniques↗
PubMed1978

Polymyositis in Chagas's disease.

Polymyositis marked the clinical onset of Chagas's disease in a patient with rheumatoid arthritis. This is unusual, although clinically unimportant muscle involvement in trypanosomiasis has been described. The plasma cell infiltrate and vascular deposition of IgM and C3 suggest that the humoral immune system may play a role in the pathogenesis of chagasic polymyositis. It is not known whether the rheumatoid diseases predisposed to the polymyositis.

Adult↗
PubMed1978

Tumor-induced immunosuppression.

Three tumor systems, including a mastocytoma, plasmacytomas, and a leukemia-lymphoma were studied for their ability to modify humoral immunity to sheep erythrocytes both in vivo and in vitro. All tumors resulted in a depression of the hemolytic antibody plaque-forming cell response in susceptible mice. These studies indicated that the mechanism(s) of suppression, although not fully defined, were different for each model system investigated.

Animals↗
PubMed1978

Macrophage-induced reversal of immunosuppression by leukemia viruses.

Suppression of the humoral immune response by several murine leukemia viruses has been well documented. However, the mechanism of suppressed immunoresponsiveness is not well characterized. Macrophages have been reported to be intimately involved in host-tumor relationships, and were therefore examined for their role in reversing suppression in two leukemia virus-induced tumor models. In vivo studies with the Friend leukemia virus (FL virus) were unsuccessful in demonstrating any role for stimulated peritoneal exudate (PE) cells, rich in macrophages, in restoration of antibody function in leukemic mice. However, in vitro studies with FL virus demonstrated that proteose-peptone stimulated PE cells from normal syngeneic mice in restricted numbers (1-3 x 10(5)), when added to 5 x 10(6) FL virus infected spleen cells, could partially restore immunity. Furthermore, using the Rowson-Parr virus (RP virus) model system it was shown that PE cells from RP virus-infected mice, as well as normal PE cells, were capable of restoring immunocompetence. Neither splenic adherent cells nor lymphoid cells from other tissues, when added to RP virus-infected spleen cells, were able to induce recovery of the immune response. In addition, treatment with antitheta serum plus complement had no effect on the ability of PE cells to restore immunity, implying that macrophages were solely responsible for reversal of immunosuppression. An alteration of antigen "processing" or "focusing" may be an important mechanism by which recovery of immune competence is achieved.

Animals↗