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M Simon

Publications and source records attributed to M Simon.

At least 703 records · Page 39Linked to original sources
PubMed1976

The identification of the mot gene product with Escherichia coli-lambda hybrids.

Molecular cloning techniques were used to construct lambda-E. coli hybrid bacteriophage carrying genes involved in bacterial flagellar motility (mot) and chemotaxis (cheA). A series of hybrid bacteriophage without each of these genes was also prepared. When paralyzed mutants of E. coli were infected with lambda that carried the mot gene, the ability of the bacterium to swim was rapidly restored. The restoration of motility was the result of the synthesis and insertion into the cell membrane of a protein with an apparent molecular weight of 31,000 (the Mot protein). Another polypeptide with a mobility on acrylamide gel electrophoresis which corresponded to a molecular weight of 39,000 was associated with the cheA gene. The presence of this polypeptide alone was not sufficient to restore chemotactic activity to mutant cheA strains. It was suggested that only a portion of the cheA gene was cloned, and thus the 39,000 protein may be a partial product of the cheA gene, or the product of a second mot gene.

Bacterial Proteins↗
PubMed1976

Linkage of the pig main histocompatibility complex and the J blood group system.

Linkage of the main histocompatibility complex (MHC) and the J blood locus was demonstrated in pgis by means of segregation data in families of double back-cross matings. A recombination frequency of 9.82% was estimated. No evidence of close association with the blood group systems A, B, D, E, F, G, H, I, K, L, M, N and O was found.

Animals↗
PubMed1976

Association of HLA-A3 and HLA-B14 antigens with idiopathic haemochromatosis.

The frequency of HLA-A3 and HLA-B14 antigens was significantly higher in a series of 51 patients with idiopathic haemochromatosis than in a control group, being respectively 78-4 versus 27-0% and 25-5 versus 3-4%. This finding strongly supports the suggestion that idiopathic haemochromatosis is a genetic disease and suggests that the gene(s) responsible for the disease may be linked to the histocompatibility genes.

Adult↗
PubMed1976

[Diabetes of idiopathic haemochromatosis and common diabetes mellitus. Results of a prospective study of 97 families with idiopathic haemochromatosis (author's transl)].

The purpose of this study was to investigate through an epidemiological approach two controversial aspects of the pathogenesis of the diabetes mellitus of idiopathic haemochromatosis (I.H.) : the possible inheritance of the gene(s) for common diabetes mellitus (C.D.), and the diabetogenic role of iron overload. More than 80% of the living first degree relatives of 97 patients with I.H. were examined, while data were collected by inquiry concerning first degree relatives who had refused investigations or had died. Data on the more distant family members were also collected by inquiry. Physical examination and estimation of serum iron level and unsaturated-iron-binding capacity were systematically performed. When an anomaly had been thus detected further investigation for iron overload was carried out by mean of a deferoxamine test and eventually by liver biopsy. Evaluation of carbohydrate metabolism included testing for post-prandial glycosuria, estimation of post-prandial blood sugar, and eventually an oral glucose tolerance test. The results were compared to those of an inquiry for family history of diabetes in 100 patients with C.D. successively admitted to our department. Among the first degree relatives of patients with C.D. the prevalence of overt diabetes was 33 of 612 (5.4 %); whereas in the I.H. group it was 8 of 735 (1.1 %). The differences between the C.D. and I.H. groups were significant, whether the total I.H. group (p less than 10(-5)) or only I.H. proposite having overt diabetes (p less than 2 X 10(-2)) were considered. With respect to the more distant relatives the number of affected families was significantly higher in the C.D. group (31 of 100) than in the total I.H. group (5 of 97 ; p less than 10(-5)) or in the I.H. sub-group diabetic proposite (3 of 36 ; p less than 10(-2)). The frequency of carbohydrate intolerance in relatives bore no relation to the carbohydrate pattern of propositi. Carbohydrate intolerance was frequently found in relatives with iron overload (17 of 72). However, no correlation was observed between blood sugar and serum iron level or unsaturated-iron-binding-capacity, relatively gross parameters. Thus, the pathogenesis of diabetes mellitus associated with I.H. remains uncertain, but the inheritance of gene(s) for common diabetes is unlikely to play a determinant role.

Adolescent↗
PubMed1976

Macrophage requirements of CR- and CR+ B lymphocytes for antibody production in vitro.

A Sephadex G-10 column coated with antigen-antibody complexes and complement retains complement receptor-bearing (CR+) mouse spleen cells. The effluent is rich in thymus-derived cells (T cells), and contains bone marrow-derived cells (B cells) which carry surface immunoglobulin (Ig), Ir-associated antigen (Ia), and Fc receptors, but no complement receptors (CR-). Although both unfractionated and CR- B cell populations are capable of producing antibody to red cell antigens, they differ in their requirements for the initiation of the response. Unfractionated B cells cooperate with primed as well as unprimed helper T cells; macrophages are required for this cooperation but can be replaced by 2-mercaptoethanol. CR- B cells cooperate with primed but not with unprimed T cells provided macrophages are added to cultures. After addition of culture supernatant from BCG-activated macrophages CR- B cells cooperate with both unprimed and primed T helper cells.

Animals↗
PubMed1976

Studies on megacinogeny in Bacillus cereus. II. Bacillus cereus isolates characterized by prophage-controlled production of megacin A (phospholipase A).

Five out of a number of Bacillus cereus strains isolated from soil produced high titre specific bacteriocin (megacin A) in mitomycin C-induced cultures. In the course of cultivation with ethidium bromide, the strains gave off segregants not producing bacteriocin (cin-). The lysate of two wild strains formed plaques on the corresponding cin- bacteria. The two phages (wx23 and wx26) were identical in antigenic structure with phage wx was present in the lysate of B. cereus strain W, and converted cin- derivatives into cultures producing megacin A (phospholipase A). The phages produced plaques at 26 degrees C but not at 37 degrees C. In the lysates of the remaining three strains phages were not detected with biological and morphological methods; these cultures have been assumed to carry defective prophage genome. As the corresponding prophages are responsible for the determination of inducible phospholipase A production, phages named wx seem to form a separate group of B. cereus phages.

Bacillus cereus↗
PubMed1975

Septal apertures in the humerus of normal and experimental rats.

Septal apertures of the humerus are rare in wild and domesticated rats but their occurrence is more frequent in females than in males and on the left than on the right side. Septal apertures can be produced experimentally by hypophysectomy due to an extreme reduction of the thickness of the septal wall. Other endocrine ablations, starvation and unilateral front leg paralysis do not produce a sufficient reduction of septal wall thickness to cause septal apertures. Their occurrence is also not correlated with total humeral robusticity. Thus, the manifestations of septal apertures in a non-specialized mammal such as the rat do not differ from those in higher primates.

Animals↗
PubMed1975

Acute morphine effects on regional brain amines, growth hormone and corticosterone.

Morphine sulfate was injected in doses of 5, 10 and 20 mg/kg i.p. to male rats at 3:00 pm. At 4:00 pm, the rats were decapitated and norepinephrine, dopamine and serotonin levels were measured in seven brain regions (cortex, striatum septum, amygdala, hypothalamus, midbrain and pons). Growth hormone and corticosterone levels were assayed from plasma. Saline-injected animals served as controls. The only significant change in brain amine level was an increase in striatal dopamine which occurred after 5 mg/kg morphine. 20 mg/kg caused an increase in plasma corticosterone; lower doses were ineffective. The dose for maximum growth hormone release was 10 mg/kg, although all three doses were effective. It was not possible to relate changes in brain amine levels with these hormonal responses to acute morphine administration.

Amines↗
PubMed1975

Chronic morphine effects on regional brain amines, growth hormone and corticosterone.

This study was designed to examine the relationship between regional levels of brain amines (norepinephrine, NE; dopamine, DA; serotonin, 5-HT) and plasma hormone levels (corticosterone, CS; growth hormone, GH) in rats following chronic morphine administration (40 mg/kg twice daily). Rats were sacrificed at 4:00 pm (and the final injection was made at 9:00 am). Amine and hormone levels were determined after 1, 2 and 6 weeks of daily injections of morphine. Increased plasma CS was found after 1 and 2 weeks of injections and decreased GH levels were present after 2 and 6 weeks. In another 2 week study when morphine was administered 1 hr before sacrifice, plasma levels of CS were decreased and GH increased. Serotonin levels were decreased in all brain regions after 2 and 6 weeks of morphine administration and DA was decreased in the amygdala after 6 weeks. In 2 weeks treated rats injected 1 hr before sacrifice 5-HT levels had returned to control levels and DA was decreased. Inverse correlations were found to relate with 5-HT and CS levels, CS with GH levels and GH with brain DA. A direct correlation was present in GH and 5-HT levels.

Amines↗