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Biomedical subjects

M Dinowitz

Publications and source records attributed to M Dinowitz.

29 records · Page 2Linked to original sources
PubMed1977

Transfer of delayed hypersensitivity in mice to microbial antigens with dialyzable transfer factor.

Dialyzable Lawrence-type transfer factor was prepared from the spleen cells of CF1 mice inoculated with Coccidioides immitis- and Candida albicans-killed vaccines and with live Mycobacterium tuberculosis vaccine (BCG). These preparations were shown to transfer antigen-specific cell-mediated immunity to naive mice, as measured by the delayed skin test and footpad-swelling methods. Reactivity could be demonstrated when the test antigens were given 24 h after the transfer factor, but not when they were given simultaneously. Coccidioides-specific transfer factor was shown to be sensitive to Pronase and resistant to trypsin and ribonuclease. A preparation of BCG transfer factor was sensitive to snake venom phosphodiesterase.

Animals↗
PubMed1977

Susceptibility of murine transfer factor to dimerized ribonuclease A.

Dialyzable transfer factor was prepared from the spleens of CF1 mice actively sensitized with killed Coccidioides immitis antigen. The transfer factor was administered to normal mice either intraperitoneally or into the hind footpads. The recipient mice were tested for reactivity to the coccidioides antigen and to Candida albicans antigen by means of the footpad swelling test. The transfer factor conferred antigen-specific reactivity upon normal recipient mice when given by the intraperitoneal and footpad routes. This capacity of the transfer factor was destroyed by in vitro pretreatment with dimerized ribonuclease A, an enzyme active against double-stranded, as well as single-stranded, ribonucleic acid. In contrast, monomeric ribonuclease A, which is active against only single-stranded ribonucleic acid under the conditions used here, was without effect upon the transfer factor. These data provide evidence that murine transfer factor contains ribonucleotides that are essential for immunological activity. In addition, the data are consistent with the hypothesis, advanced by others, that the ribonucleotides may be double-stranded or uniquely looped configurations.

Animals↗
PubMed1976

Delayed hypersensitivity to fungal antigens in mice. I. Use of the intradermal skin and footpad swelling tests as assays of active and passive sensitization.

Mice were sensitized to Coccidioides immitis and Candida albicans antigens and tested for sensitivity by the intradermal and footpad swelling methods. In mice actively sensitized with killed antigen, antigen-specific intradermal and footpad induration responses occurred 24 and 48 hr after sensitization. Antigen-specific intradermal and footpad responses were transferred to normal mice with spleen cells from immune animals. Such responses were also transferred with normal spleen cells that had been incubated in vitro with immune RNA preparations. Histologic studies of intradermal reactions showed a mixed response of neutrophilic and mononuclear leukocytes, with slight vascular involvement compatible with delayed hypersensitivity. No intradermal or footpad responses were observed 4, 24, or 48 hr after injection in recipients of serum from actively sensitized mice. Histologic examination of skin sites in these mice revealed only a polymorphonuclear response. It is concluded that these intradermal and footpad responses are the result of delayed hypersensitivity and can be used as assays for this type of immunity in mice.

Animals↗
PubMed1976

Delayed hypersensitivity to fungal antigens in mice. II. Molecular classes in immunogenic RNA extracts that transfer delayed hypersensitivity.

The transfer of delayed hypersensitivity to Coccidioides immitis and Candida albicans antigens with immunogenic RNA extracts was studied in a mouse model. Sensitivity was measured by skin tests and footpad swelling responses. Immunogenic RNA converted normal spleen cells in vitro so that they produced antigen-specific delayed hypersensitivity in mice that were given injections of the cells. RNase reduced the rate of, but did not abolish, in vitro interaction of immunogenic RNA extracts with lymphocytes. Immunogenic RNA transferred sensitivity on direct intraperitoneal inoculation into mice. The transfer ability was resistant to RNase preparations active against both single- and double-stranded RNA. Sedimentation gradient fractions of the immunogenic RNA were assayed by intraperitoneal injection, and converting activity was found in two fractions, greater than 33S and 6S-13S. After treatment with RNase, all activity was shifted to the less than 6S fraction. Two fractions of the immunogenic RNA in its native state (greater than 33S and 6S-13S) were also able to convert spleen cells. The data indicate that the transfer of delayed hypersensitivity by immunogenic RNA preparations is associated with RNA but may not require the intact RNA molecule.

Animals↗
PubMed1976

Delayed hypersensitivity to fungal antigens in mice. II. Characterization of the active component in immunogenic RNA extracts.

In a mouse model, cell-mediated immunity to Coccidioides immitis, as assayed by the delayed hypersensitivity skin test, was transferred with whole immunogenic RNA extract and its greater than 33S and 6S-13S sedimentation fractions. Both fractions were cleaved by RNase, but the products retained their transfer activity. The greater than 33S fraction of immunogenic RNA extract was inactivated by pronase, whereas the 6S-13S fraction was resistant to the proteolytic enzyme; however, after RNase treatment the latter fraction was sensitive to pronase. This finding suggests a protective role for RNA. Dialysis of immunogenic RNA extract yielded a dialysate with a ratio of absorbance at 260 nm to that at 280 nm (A260:A280) of 1.02. Similarly, the dialysis product of RNase-treated RNA is active and has an A260:A280 ratio of 1.34. The data indicate that at least part of the active moiety of immunogenic RNA extracts is an RNA-associated, pronase-labile peptide or nucleopeptide. Furthermore, it is possible that the dialyzable transfer factor may be the same peptide or nucleopeptide cleaved from immunogenic RNA during preparation of the transfer factor.

Animals↗
PubMedDate not supplied

Thirteen-week toxicity study of d-alpha-tocopheryl acetate (vitamin E) in Fischer 344 rats.

A 13-wk study was conducted by administering d-alpha-tocopheryl acetate (vitamin E) in corn oil by gavage to groups of ten male and ten female Fischer 344 rats at doses of 0, 125, 500 or 2000 mg/kg body weight daily for 13 wk. The dose of corn oil given was 3.5 ml/kg. Additional groups of ten males and ten females were included and served as untreated controls. Deaths occurred only in males at 2000 mg/kg. Vitamin E dosing had no effect on body weight or food consumption. The liver-to-body weight ratio of females at 2000 mg/kg was significantly increased. In males, high levels of vitamin E (2000 mg/kg) caused prolongation of both prothrombin and activated partial thromboplastin (APTT) times, reticulocytosis and a decrease in haematocrit values and haemoglobin concentrations. APTT was also lengthened in females at this dose level. High levels (2000 mg/kg) caused haemorrhagic diathesis in both males and females and increased medullary erythropoiesis in the spleen of one male. Vitamin E at all doses tested caused interstitial inflammation and adenomatous hyperplasia of the lung. The above findings indicate that vitamin E administration in excessive amounts is potentially toxic.

Administration, Oral↗
PubMedDate not supplied

Sudden painless visual loss.

Common signs and symptoms of temporal arteritis include headache, scalp tenderness, jaw claudication, anemia, and an elevated sedimentation rate (ESR). Severe complications can include blindness, retinal artery occlusion, and optic neuropathy. While temporal arteritis may be suggested by patient history, other causes that can mimic its presentation must be considered, especially when visual loss occurs in the setting of a normal funduscopic exam. We report a case of invasive sino-orbital aspergillosis that mimicked the clinical signs and symptoms typically associated with temporal arteritis. A high index of suspicion and appropriate radiological and laboratory studies prevented delays in formulating the correct diagnosis and treatment plan.

Aged↗