Biomedical subjects
Publications and source records attributed to J Louis.
Using the Ames Salmonella/microsomal assay, mutagens were detected in acetone-methylene chloride extracts of black threads on glass tube-type sterilization indicators used in hospitals and research laboratories. Extracts of samples of commercially available black thread also contained mutagenic substances. Fluids autoclaved with these sterilization indicators may alter the results in mutagenicity and other studies.
The break of dormancy and the early development of Artemia are known to occur in the absence of any DNA and RNA synthesis. The presence and function of preformed messengers in the developing embryos were studied using 32PO4 to track the RNA species that turnover. The rapid labelling of the poly(A) tails of the particulate RNA by 32PO4 is found to be the predominant metabolic event accompanying initiation of development. Although these RNA populations represent a meagre percentage of the total poly(A) RNA of the cells, they nevertheless constitute more than 60% of the labelled poly(A) populations at early stages of development. Moreover the rise in the poly(A) RNA levels of the embryos observed during the first four hours of development could be attributed to the increase in the particulate poly(A) RNA. Prelabelled RNA of this fraction remained rather firmly associated with this fraction in chase experiments, indicating that once processed these RNA species function in association with membranes. The observed shift in the size of these RNAs from low to high molecular weight species further implies that they are being activated to take part in the early developmental programme.
It is well established that cytotoxic T lymphocytes (CTL) specific for the male minor histocompatibility antigen (H-Y) are generated by restimulation in vitro of in vivo primed spleen cells from C57BL/6 (H-2b) female mice with syngeneic male spleen cells. When tested on target cells from H-2 different strains, the male-specific C57BL/6 CTL populations exhibited significant lysis of DBA/2 (H-2d), A (H-2a), but not C3H (H-2k), male and female target cells. In an attempt to document this cross-reactivity further at the clonal level, a sensitive technique of limiting dilution analysis was used to determine the specificity of C57BL/6 individual CTL precursors (CTL-P) reactive against the male antigen. The mean frequency of anti-H-Y CTL-P in spleens of primed female mice was about 1/3500. Between one-third to one-tenth of these CTL-P produced a progeny that cross-reacted with H-2d (allogeneic) female target cells. These findings were confirmed by the analysis of the reactivity pattern exhibited by male-specific CTL clones derived by limiting dilution. Of 99 clones tested, 13 were found to cross-react with female DBA/2 target cells. These results thus indicate that a relatively large proportion (greater than 10%) of H-2b CTL-P directed against the H-Y antigen cross-react with target cells expressing H-2d alloantigens in the absence of H-Y antigen.
A North African brother and his sister, whose parents were first cousins, presented with the same disorder. It consisted of congenital dwarfism, facial dysmorphy and several skeletal anomalies including bilateral agenesis of the ala of scapula and hypoplasia of the ala of ilium and acetabulum, responsible for hip dislocation. No similar case was found in the literature. A recessive autosomal transmission of the disease is suggested.
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A modified Papanicolaou staining procedure using diluted Harris' hematoxylin with potassium alum is described. Nucleolar staining varies from blue to bright red. This technique has been applied to mammary tumor cell lines in vitro under several conditions of hormonal stimulation known to induce protein synthesis and cell differentiation. Blue nucleoli are observed in control resting cells, while bright red nucleoli are seen after hormonal stimulation.
Previously, we described a system allowing the study of murine T cell-dependent proliferative responses to Trypanosoma brucei antigens. It was observed that T. brucei-specific T cells could be demonstrated in the regional lymph nodes of primed mice for only 2 to 3 weeks following priming. The results of the present study indicate that this inability to demonstrate a long-lived memory response is due to an immunosuppressive effect of the resulting T. brucei infection. The exact mechanism of the suppression is not known, and appears to function in the absence of demonstrable suppressor cells. Since the T cell responses are strictly dependent on the presence of macrophages, we have investigated whether the loss in responsiveness is due to a defect in the T cell population, or to a loss of macrophage function. Our results show that T cells taken from mice 3 weeks after priming with T. brucei are unable to mount a proliferative response in the presence of a normal macrophage population, and conversely that macrophages taken 3 weeks after infection with T. brucei are unable to elicit a normal proliferative response using a competent primed T cell population. Thus these results indicate that both populations are affected by the parasite infection.
Hemoglobin Great Lakes, beta 68 (E12) Leu replaced by His is a new high oxygen affinity hemoglobin variant discovered in a 29-yr-old female having numerous hospitalizations for thrombophlebitis associated with mild erythrocytosis. The mutant hemoglobin has normal stability and normal electrophoretic mobility, but increased oxygen affinity (P-50 16.1 mm Hg at 37 degrees C, pH 7.4) and reduced cooperativity. The abnormal beta-chain could be separated on globin chain chromatography on carboxymethyl/cellulose in spite of the normal electrophoretic mobility of the intact hemoglobin. The leucyl residue at beta 68th position (E12) is in the middle of E-helix, which is part of the heme pocket and next to the valine (E11), which is the heme binding site. The substitution of proline for leucine in hemoglobin Mizuho resulted in the distortion of tertiary structure of the beta-chains and lead to a serious instability of hemoglobin molecule. However, the substitution of this residue by histidine in hemoglobin Great Lakes is not associated with hemoglobin instability.
Circulating immune complexes (CIC) have been studied in one or several serum samples obtained from 249 patients with cancer. 42.4% of patients with evolutive tumors and 26.9% of patients in complete remission have elevated levels of CIC. It appears that, in approximately one case out of 3, the presence of CIC is not necessarily in relationship with the tumor, but could be the consequence of other clinical factors. In some instances, repeated plasmapheresis results in decreased CIC levels. The specificity of the antibodies present in CIC is not yet known.
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The author points out a simple chromatographic technic to fractionate venom of Androctonus mauretanicus (Pocock, 1902) from Morocco.
The study of venom components of Androctonus mauretanicus (Pocock, 1902) from Marocco points out that hemolymph is constituted of hemocyanin and of slighter molecular weight other products. Besides, the toxins are strongly basic.
In comparison to the United States as a whole and to their total population age-adjusted rates, the New Jersey-New York-Philadelphia Metropolitan Region was found to have excessively high childhood leukemia and high young adult Hodgkin's disease and lymphoma cancer mortality rates in the period from 1950 to 1969.
The injection of bacterial lipopolysaccharides (Salmonella typhimurium and Escherichia coli LPS) has been shown to induce thymocytotoxic autoantibodies in various strains of mice (C57BL/6, BALB/c, DBA/2, AKR, A/J and C3HeB/FeJ). Titers up to l:16 were observed. Such antibodies did not develop in C3H/HeJ mice which are low responders to LPS. The thymocytotoxic antibodies had the following characteristics: (a) 2-mercaptoethanol sensitivity, (b) optimal reactivity at 4 degrees C, (c) cytotoxicity for autologous and syngeneic thymocytes but not for spleen cells. The cytotoxicity decreased after absorption with thymocytes, spleen cells or brain tissue but not with kidney or liver homogenates. These LPS-induced thymocytotoxic antibodies were similar to the natural thymocytotoxic antibody occurring in NZB mice.
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Spleen cells from mice exposed to 500 rad sublethal whole-body irradiation before immunization with 100 x 10(6) allogeneic spleen cells exhibited an enhanced cytolytic T-lymphocyte (CTL) activity. In contrast, this treatment completely abrogated the humoral alloantibody response, as measured by complement-mediated lysis. In addition to the observed dissociation between primary humoral and cell-mediated responses, the character of the in vitro secondary CTL response of spleen cells obtained from mice sublethally irradiated before alloimmunization was also modified. Although these spleen cells were perfectly capable of mounting a secondary response upon restimulation in vitro with intact allogeneic spleen cells, they were no longer capable of responding to subcellular alloantigen preparations. These results suggest that the cellular requirements for the induction of secondary CTL responses in vitro depend upon the nature of the antigen used for restimulation.
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