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H Winking

Publications and source records attributed to H Winking.

87 records · Page 5Linked to original sources
PubMed1984

Characterization of a recombinant mouse T haplotype that expresses a dominant lethal maternal effect.

The twLub2 chromosome was generated by rare recombination between a complete t haplotype and a wild-type form of mouse chromosome 17. This recombinant chromosome expresses a dominant lethal effect in all embryos that inherit the mutant chromosome from their mothers. The phenotype of this maternal effect is indistinguishable from that expressed by the previously described Thp deletion chromosome. It appears likely that the crossing over event that gave rise to twLub2 was unequal and resulted in the alteration or deletion of a gene (which is named the T-associated maternal effect locus, Tme) that must be inherited from the mother in order for normal development to proceed through late stages of gestation. The results presented here allow a mapping of the Tme locus between the quaking and tufted loci which are 3 cM apart within the proximal region of chromosome 17.

Animals↗
PubMed1984

An extra segment in chromosome 1 of wild Mus musculus: a C-band positive homogeneously staining region.

An extra segment in chromosome 1 between bands C5 and D has been found in wild mouse populations. Its size varies between 6.1% and 30.1% of the length of a standard chromosome 1. It differs among individuals and populations but is constant in a genetically homogeneous line. According to its staining properties and variation in length it is a homogeneously staining region (HSR), a kind of segment otherwise found only in cell lines under strong selection and in tumor cells. G-banding gives a homogeneous staining of medium intensity. With C-banding, staining is positive, though lighter than that of centromeric heterochromatin. Fluorescence is dull with Hoechst 33258 and bright with mithramycin. The extra segment does not contain mouse satellite DNA sequences in any quantity detectable by in situ hybridization. Such an extra segment was found in several European populations of mice from Spain to Russia. It is carried through the germ line. It has been introduced into a laboratory mouse strain, and, by recombination, inserted into a Robertsonian metacentric chromosome for easier handling and identification.

Animals↗
PubMed1983

Murine trisomy: developmental profiles of the embryo, and isolation of trisomic cellular systems.

Many questions related to the development and the phenotypic expression of trisomy (Ts) are amenable to systematic investigation in a mouse model that allows the induction of Ts 1 to 19 by a breeding design of mice heterozygous for Robertsonian metacentric chromosomes. Some Ts do not survive the first critical phase of organogenesis on days 11 to 12 of fetal development; others as Ts 12, 14, 16, 18, and 19, have a life span until or beyond birth. Model type studies of the morphogenesis of developmental anomalies (e.g. craniocerebral, cardiovascular, or placental) are possible in Ts with a longer developmental span, and Ts 16 of the mouse is considered as a natural model of human trisomy 21. The eventual breakdown and death of the trisomic organism are inevitable. There is considerable interest to find ways for rescue and longer survival of Ts in competitive developmental systems, as e.g., in Ts in equilibrium with 2n blastocyst chimeras, or by isolation of trisomic cellular or tissue systems. Thus, the transfer of Ts hemopoietic stem cells of the fetal liver to irradiated adult recipients is a means of studying the functional capacities and maturation of trisomic hemopoiesis and lymphopoiesis. Both are almost completely restored by Ts 12, 14, 18, and 19 stem cell transplantation with survival periods of more than 6 months. But in other Ts, as of chromosomes 13 or 16, such capacity of reconstitution is impaired. The stepwise analysis of the effects of chromosome triplication on the cell level, in isolated functional systems and in the embryonic organism, is a promising way to understand the phenotypic expression of genome anomalies in complex developmental processes.

Animals↗
PubMed1983

Down's syndrome in the male. Reproductive pathology and meiotic studies.

Studies on testicular histology and meiosis were carried out by the use of light and electron microscopy in an 18-year-old Down's syndrome male in an attempt to follow the fate of the extra chromosome 21 and to evaluate the effects of this condition on spermatogenesis and the reproductive functions. The histological changes in the testes corresponded to spermatogenic arrest. Electron microscopic whole-mount spreadings of meiotic cells in the pachytene stage showed that in most nuclei an extra chromosome 21 was not detectable. Only in a small number of nuclei, univalents or trivalents with segmental pairing structures of an extra chromosome could be discovered. In contrast, the great majority of (C-banded) diakinesis figures showed the presence of a supernumerary G (no. 21) chromosome. The absence of a traceable extra chromosome 21 in most pachytene cells is explained by the assumption that it is intimately connected with and hidden in the sex vesicle, whose complex structure does not allow the identification of single elements. Strong support for this assumption is seen (a) in the general tendency of narrow spatial association of unpaired segments with the XY complex and (b) in close structural similarities occurring between univalents or nonsynapsed segments of trivalents and the nonpaired segments of the sex chromosomes. It is suggested that the association or connection of an extra chromosome with the XY complex during pachytene interferes with the phenomenon of X inactivation. In animal systems such abnormal interference is related with spermatogenic breakdown and, in a general way, with male hybrid type sterility. So far, the range of sterility vs. fertility in cases of male Down's syndrome is not yet fully clear, but it appears that impairment of fertility, and sterility are most frequent. If so, it is proposed that the effect of the trisomy 21 condition on spermatogenesis (and fertility) is a consequence of the behavior of the extra chromosome in the meiotic prophase.

Adolescent↗
PubMed1982

Trisomy 16 in the mouse fetus associated with generalized edema and cardiovascular and urinary tract anomalies.

Murine trisomy (Ts) 16 occurs in the fetal and neonatal progeny of males doubly heterozygous for the Robertsonian metacentric chromosomes Rb(16.17)7Bnr/Rb(9.16)9Rma and "all acrocentric" females. The developmental aspects of this trisomy were studied between day 12 of gestation and birth. So far, postnatal survival longer than a few hours after birth has not been observed. The frequency of Ts 16 among all implants decreased from more than 20% on day 14 to values between 4% and 7% shortly before term. Main features of Ts 16 are moderate general hypoplasia, slight developmental retardation, and cardiovascular anomalies. These latter were found in 96% of the trisomies, the great majority belonging to the transposition type, i.e., riding aorta, double outlet right ventricle (DORV) and transposition of the great arteries (TGA). Association with common atrio ventricular (AV)-canal was frequent. Other anomalies as "open eyelid", hydronephrosis, and hydroureter seem to be attributable to the effects of retardation. Generalized transient edema was frequent in the later gestational stages of Ts 16. Severe cardiovascular malformation is possible one of the factors responsible for late fetal or neonatal death in some cases. Another factor probably contributing to Ts 16 fetal mortality is insufficiency of placental function due to hypoplasia of the fetal vasculature of this organ. The teratological study of Ts 16 demands interest since evidence has been forwarded to consider this trisomy as an animal model of human trisomy 21.

Animals↗
PubMed1982

Robertsonian karyotype variation in wild house mice from Rhaeto-Lombardia.

The European longtailed house mouse (M. m. brevirostris and domesticus) in the Rhaetian Alps and Lombardia presents a complex system of Robertsonian (Rb) variation and karyotype diversity, several adjoining populations homozygous for multiple Rb metacentric chromosomes, sites of coexistence of different Rb types, and zones of hybridization with non-Rb populations. The original "tobacco mouse" is just one of many local Rb variants, such as those from other Alpine areas (e.g., Orobian Alps) or from Central Lombardia, where a relatively large region within which the population is homogeneous for multi-Rb metacentrics is found. The present study is based strictly on material in which the chromosome arms were identified by G-banding, so that karyotypes within the areas under investigation could be compared. Altogether 111 mice were studied.

Animals↗
PubMed1981

The pattern of early replicating bands in the chromosomes of the mouse.

Early replication of mouse chromosomes was studied with the BrdU-Hoechst-Giemsa technique. With the help of different Robertsonian translocation chromosomes as markers, chromosomal bands that replicate early were identified. An idiogram of each chromosome was constructed. The array of replicating bands along the chromosome fits well into the existing nomenclature based on G-banding. The karyotype presented is useful for R-banding studies as well.

Animals↗
PubMed1980

Variable positions of NORs in Mus musculus.

Silver-NOR staining has been applied to mouse (Mus musculus) chromosomes of different feral populations from Italy, Yougoslavia, and Germany and to chromosomes of M. spretus, a closely related species, from Portugal. In addition to the known pattern of proximal sites on smaller autosomes, terminal sites with silver-NORs on chromosomes 4 and 13 were detected. In M. spretus only terminal NORs were present on chromosomes 4, 13, and 19. Thus, the location of silver-NORs within the genus Mus and M. musculus subspecies shows wide variation.

Animals↗
PubMed1980

Histocompatibility-2 system in wild mice. X. Frequencies of H-2 and Ia antigens in wild mice from Europe and Africa.

In this study, data are presented on serologic H-2 typing of 320 wild mice collected in several parts of Europe and Egypt. The sample was typed for 39 class I (K, D) and 16 class II (Ia) antigens. The phenotype frequencies of class I and class II antigens showed high variability in their distribution among different areas, ranging from absence or presence in low frequency in one area to presence in about one-half of the mice in another area. The average phenotypic frequency of class I private antigens was 6.3%; at least 60% of class I alleles (blanks) could not be identified with the available reagents. The data suggest that there might be more than 100 alleles for each class I locus, H-2K and H-2D. The average phenotypic frequencies of Ia-1 private antigens was 10.8%. About 75% of Ia-1 alleles (blanks) could not be identified. The number of Ia-1 alleles was estimated to be in the range of 20 to 50.

Alleles↗
PubMed1976

Robertsonian metacentrics in the mouse.

A survey is given on the occurrence, the geographic origin and the arm composition of 27 Robertsonian fusion metacentric chromosomes of wild populations of the mouse. Their study is of twofold interest: a) it is possible to introduce these naturally occuring metacentrics in laboratory strains for experimental use. At present, altogether 34 metacentric chromosomes of different composition are available including 7 cases of metacentrics known form laboratory strains of the mouse. b) With the search for metacentrics in the mouse and with their identification insights are permitted in the role of Robertsonian changes in the course of mammalian evolution--Several separate populations of the mouse with different sets of multiple (up to 9) metacentrics have been found in Switzerland and Italy. Some of the individual metacentrics may occur in different populations. The participation of an acrocentric autosome in the formation of metacentrics seem to be at random, but the sex chromosomes are never included in a metacentric.--Homology of the arms involved in metacentrics is conserved, so that in meiosis of interpopulation hybrids is due to mechanisms of segregational imbalance and subsequent prenatal elimination of fetal offspring, but it follows also the pattern of male limited hybrid sterility.--From an evolutionary view point, karyotype rearrangements of Robertsonian type may initiate reproductive isolation, which prepares the ground for further genetic diversification and, as in the case of the mouse, of incipient speciation.

Animals↗
PubMedDate not supplied

Altered action potential of myocardial cells from mouse fetuses with trisomy 16: a model of Down syndrome.

BACKGROUND: Trisomy 21 in humans and trisomy 16 in mice (a model of Down syndrome) are associated with increases in rates of depolarization and repolarization and decreases in duration of action potential of neurons, due to overexpressing protein subunits of Na(+) and K(+) channels in a gene dose-dependent manner. These chromosomes also have genes for voltage-gated Na(+) and K(+) channels expressed by myocardial cells. Thus, it would be expected that heart cells would have alterations in their action potentials similar to those found in neurons in both aneuploidies. METHODS: Myocardial cells from normal and trisomy 16 mouse fetuses were compared in relation to their electrical membrane properties using intracellular microelectrodes. RESULTS: At 13 and 17 days of gestation, trisomic cells, as compared with control cells, had higher amplitude and rates of depolarization and repolarization, with lower duration of plateau of action potential at 25, 50, and 75% of repolarization. This suggests that Ca(2)+ influx is reduced in trisomic cells, which could impair Ca(2)+-dependent fetal myocardial functions (i.e., contractility or matrix secretion). CONCLUSIONS: Myocardial cells of Ts-16 mice showed electrophysiologic alterations qualitatively similar to those observed in trisomic neurons, in agreement with the gene dose-dependent hypothesis (see Introduction).

Action Potentials↗
PubMedDate not supplied

Stage-dependent enzymatic activities in spermatogenesis of mice with the standard karyotype and of chromosomal variants with impaired fertility.

The enzymatic activities of thiamine pyrophosphatase (TPPase), acid phosphatases (ACPases), alkaline phosphatases (APases) and steroid-3 beta-ol dehydrogenase (beta-HSDH) in different germ cells and somatic cells in the testis of three cytogenetically determined states of fertility (i.e. normal, impaired fertility and sterility) were studied histochemically in the mouse. The TPPase, ACPases and APases activities showed a characteristic stage dependent pattern when the activities were related to the typical twelve stages of the seminiferous epithelium in the mouse, according to Oakberg (1956). Comparing the enzymatic patterns of the activities in the normal spermatogenic process versus the impaired and sterile conditions, the following conclusions can be drawn: even in impaired and sterile conditions the enzymatic activity patterns retain their characteristic stage dependence; the pattern of beta-HSDH and ACPases is not altered in the impaired and sterile conditions; TPPase and APases patterns are modified in impaired and sterile mice. It is concluded that the kinetics of the enzyme activities can serve as a useful marker for characterizing pathological spermatogenic processes.

3-Hydroxysteroid Dehydrogenases↗