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S R Blecher

Publications and source records attributed to S R Blecher.

At least 37 records · Page 2Linked to original sources
PubMed1986

Epididymides of sex-reversed XX mice lack the initial segment.

The genetic factor Sxr causes sex reversal of chromosomally female (XX or XO) mice to phenotypic maleness by inducing development of testes that produce androgens. It has been considered that these sex-reversed animals, called pseudomales, confirm the principle originally developed by Jost that adequate androgenization produces normal phenotypic maleness in mammals, irrespective of chromosomal sex. However, we previously discovered that the epididymis of sex-reversed XX mice (pseudomales of genotype XXSxr) lacks EH 9 cells (epididymal head, cell type No. 9, the "principal cell' of the initial segment). The purpose of the present study was to determine whether cell type EH 9 of XXSxr pseudomales is replaced by a principal cell of a different appearance, or whether the initial segment itself is actually absent. We made serial sections of entire epididymal heads and did microdissections to unravel the highly coiled epididymal duct. Using these two approaches, we studied the sequence of epididymal segments, and estimated lengths of the relevant portion of the epididymal duct; we found that the initial segment of XXSxr pseudomales is truly absent. This is the first report of a mutant genotype causing absence of a segment of the epididymis. The XXSxr mutant appears to be an exception to Jost's principle. This finding shows that, even in full androgenization, male phenotype may not always be independent of chromosomal sex.

Animals↗
PubMed1986

Anhidrosis and absence of sweat glands in mice hemizygous for the Tabby gene: supportive evidence for the hypothesis of homology between Tabby and human anhidrotic (hypohidrotic) ectodermal dysplasia (Christ-Siemens-Touraine syndrome).

I have suggested that the X-linked gene Tabby (Ta) and its autosomal mimics in the mouse may be homologous with the genes for sex-linked anhidrotic (hypohidrotic) ectodermal dysplasia (Christ-Siemens-Touraine syndrome, CST) and its apparent autosomal mimics in the human. In the present study, I examined whether anhidrosis, a cardinal feature of CST, is present in the putative mouse sex-linked model, Tabby. The results demonstrate that whereas normal mice perspire on the volar and plantar surfaces of their paws, hemizygous Ta/Y male mice show anhidrosis and absence of sweat glands, as do human hemizygous male sufferers of CST. This result is strongly supportive of the hypothesis that Ta is homologous to the gene for CST.

Animals↗
PubMed1986

Androgen levels and androgenization in sex-reversed (XXSxr pseudomale) mouse: absence of initial segment of epididymis is independent of androgens.

The XXSxr pseudomale ("sex-reversed") mouse has an apparently normal male phenotype. This is in accordance with Jost's Principle that, in an animal with androgen-producing testes, phenotype will be fully masculinized, irrespective of chromosomal sex. However, the epididymis of this mutant lacks the Initial Segment. Several alternative explanations were proposed. In the present study we examined the primary of these, viz, androgen insufficiency. We studied androgen levels in serum and tissues of the mutant, and we investigated whether injection of exogenous androgens could induce normal development. The XXSxr pseudomale is not deficient in androgens, nor do exogenous additional androgens induce development of the Initial Segment. It would appear that the abnormal genotype acts on the organ phenotype without intervention of androgens.

Androgens↗
PubMed1983

Pleiotropic effect of Tabby gene on epidermal growth factor-containing cells of mouse submandibular gland.

The influence of the Tabby gene on the submandibular gland of the mouse was assessed by comparing the mass of the gland, and its content of granular convoluted tubules, in prepubertal, pubertal, and adult Tabby mice and their wild type brother controls. The Tabby mice showed reduction in mass of the adult submandibular gland, delayed development of the granular convoluted tubules, and reduction in relative content of granular convoluted tubules. Epidermal growth factor (EGF) is released from the granular convoluted tubules of the mouse submandibular gland, and it is known to experimentally influence the development of at least some of the structures that are affected by the Tabby gene. Accordingly, the question of a relationship between the Tabby gene and EGF is raised.

Aging↗
PubMed1983

A rapid DAPI-distamycin method for identification of the mouse Y chromosome.

In a study requiring rapid diagnosis of the chromosomal sex of mice, standard staining methods for mouse chromosomes were evaluated for speed, simplicity, and the quality of staining. None of the techniques previously used for mouse chromosomes were adequate. However, a DAPI-distamycin A method for human karyotyping was successfully adapted for this purpose.

Animals↗
PubMed1983

Evidence from thiol histochemistry for homology between the Tabby-crinkled syndrome in mice and human ectodermal dysplasia.

Mutant mice carrying the sex-linked gene Tabby (Ta), and others carrying crinkled (cr), an autosomal mimic of Ta, were studied histochemically with respect to the sulfhydryl: disulfide ratios in their skin and hair and the SH levels in their tooth germs. As compared to normal controls, the mutant animals demonstrated significantly elevated SH:S-S ratios (skin and hair) and SH levels (tooth germs) in the ectodermal components of these tissues. This finding corresponds with previously reported biochemical data on a form of human ectodermal dysplasia (ED), and therefore supports the hypothesis that these mutations in mice may be homologous to the genes for human ED.

Animals↗
PubMed1983

Histochemical studies on genetical control of hormonal enzyme inducibility in the mouse. VI. Effects of short term castration.

The regional histology and esterase activity of the mouse epididymis after 24, 48, and 72 hr castration is reported. Differential sensitivity to androgen deprivation among the various epithelial cell types is described, allowing of positive identification of the cell types previously observed to survive long-term castration. The possibility of an androgen binding protein, as described in the rat and rabbit, is suggested on morphological grounds. The epididymal body appears to contain a class of highly androgen sensitive cells that degenerate rapidly following castration and a second class that survive from which regeneration occurs on testosterone replacement.

Animals↗
PubMed1982

Reverse, hormone-dependent sex difference in molar tooth mass in pubertal mice.

The weighed mass of molar teeth of male pubertal (35-day-old) mice was significantly smaller than that of females. X0 females, and chromosomal males (XY) rendered phenotypically female by the testicular feminization gene (Tfm), had high (female-type) molar mass. Chromosomal females (XX or X0) rendered hormonally phenotypically male by the sex reversal gene Sxr, had low (male-type) molar mass. It is concluded that the sex difference was due to hormonal rather than chromosomal factors. Reported sex differences in mammalian tooth size have mainly been in the opposite direction, a discrepancy which may be due to co-existence of opposite dimorphisms of mass and diameter, or to age-specific changes in ontogeny. However, the most likely explanation is that developmental species differences exist.

Animals↗
PubMed1982

Histochemical studies on genetical control of hormonal enzyme inducibility in the mouse. V. Histochemical evidence for androgen inducibility of beta-glucuronidase in the epididymis.

The enzyme beta-glucuronidase (beta G) is shown, by histochemical methods, to be androgen inducible in the mouse epididymis. This trait has previously been believed to exist only in the kidney. Its presence in the genital tract constitutes a valuable tool in study of the developmental genetics of the reproductive system. Data presented here and previously imply co-ordinated genetic control of heterogeneous lysosomal populations. The results reported also provide a system for study of X-chromosomal activation, and of the developmental androgen dependence of the epididymis.

Androgens↗
PubMed1981

Preliminary evidence of genetic control of sex chromosomal synapsis in the mouse.

Highly inbred strains of mice have contrasting means and low ranges for the trait of gonosomal univalency at diakinesis-metaphase I. Randomly bred and mixed strains have wider ranges. The inbred strain DBA/2J has a high mean, and this character is evidently transmitted through the male parent. This material may provide a valuable model for study of genetic control of XY pairing.

Animals↗
PubMed1981

A search for a genetic basis for gonosomal univalency in mice.

The frequencies of cells with XY nonpairing at diakinesis/metaphase I were examined in random-bred ICR-Swiss, partly inbred DCH, and highly inbred DBA/2J and C57BL/6-bgJ mice. The animals in given inbred line displayed homogeneity in the proportion of cells with gonosomal univalents. In DBA/2J, the X and Y remained unpaired in 33.2% of the cells examined, whereas the corresponding frequency in C57BL/6-bgJ was only 7.0%. Previous data of RAPP et al. (1977) showed a low incidence of XY nonassociation in C57BL/6 and high frequencies in the BDF1 hybrid (C57BL6 female X DBA/2 male). We interpret our results, and the previous data of RAPP et al. (1977), to indicate the existence in mice of a genetic polymorphism for XY nonassociation. The DBA/2J strain appears to have factors that predispose to a high frequency of gonosomal univalency.

Animals↗
PubMed1981

Histochemical studies on genetical control of hormonal enzyme inducibility in the mouse. IV: Cellular localization of androgen sensitive nonspecific esterase in the epididymis.

Nonspecific esterase of mouse epididymis has previously been studied histochemically, using alpha naphthyl-acetate and 5-bromoindoxyl acetate techniques, as well as certain inhibitors. Epithelial cell types of the epididymis have been characterized, and certain esterase isozymes in a particular cell type, is shown to be androgen dependent. When mice of different strains were castrated or treated with antiandrogens, the characteristic histochemical reaction product disappeared or was greatly reduced. Androgen treatment of castrated animals caused the reaction in the cells concerned to return to normal. This method can now be applied to the study of epididymides of genetically sex-reversed chromosomal female, to analyze genetic control of X-chromosomal activation.

Androgens↗
PubMed1979

Histochemical studies on genetical control of hormonal enzyme inducibility in the mouse. III. Beta-glucuronidase distribution pattern of epididymis in different genotypes.

This article reports the application of Hayashi's histochemical technique for beta-glucuronidase to mouse epididymis. A methodological study, which established optimal conditions for demonstrating the enzyme in this organ, is reported. The distribution pattern of beta-glucuronidase is described and correlated with previous data for alpha-naphthyl acetate esterase. Differences between sites of granular and diffuse reaction product for these two enzymes are recorded. Possible interpretations of these findings in terms of intracellular localization of enzymes are discussed. Studies on different strains reveal regular differences in histochemical organization between mice of various genotypes. Histochemical data which imply androgen inducibility of beta-glucuronidase in mouse epididymis are preliminary noted.

Animals↗
PubMed1978

Studies on the oxidizing system in Holt's medium for histochemical demonstration of esterase activity.

Esterase activity in guinea-pig thyroid and mouse epididymis epithelial cells has been studied using 5-bromoindoxyl acetate as substrate. The pattern of esterase activity in the thyroid of the guinea-pig is constant, irrespective of whether ferri-ferrocyanide (FFC) or certain copper compounds are used as oxidizing agents in the incubation medium. The intensity of the coloured reaction product is increased when cobalt or manganese are added to the incubation medium. Activity is depressed by high concentrations of FFC when resent in incubation medium or preincubational buffer only. Epididymis cells contain an esterase activity which is not inhibited by conventional SH blocking agents, nor by high concentrations of FFC. From these results it appears that the mode of action of FFC in Holt's medium is as follows. At low concentrations FFC appears to act primarily as a catalytic agent in oxidation of indoxyl to indigoid. At high concentration FFC acts as an inhibitor of guinea-pig thyroid esterase, by oxidation of SH groups in the active centre. The esterase of mouse epididymis cell type EH 1 is not subject to this inhibition by FFC, presumably because it does not contain accessible SH groups in the active centre.

Animals↗
PubMed1978

Histochemical studies on genetical control of hormonal enzyme inducibility in the mouse. I. Non-specific esterase activity and regional histology of the epididymis.

As a base line for future cell genetical studies the authors record the distribution of non-specific esterase reaction in the various histologically distinguishable cell types of the mouse epididymis. The findings are correlated with previous descriptions of the lobar structure of the organ. Assuming the sequence of lobes of the head to be as implied in these classical descriptions, the esterase activity of the epithelial cells gradates between strong to weak several times along the length of the epididymal duct. The relationship of the lobes to each other, as seen in transverse sections, is described. Methodological studies using different fixatives indicate that apparent similarity of esterase reaction at different sites may camouflage an underlying difference in the nature of the esterases at these sites.

Animals↗