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  • 1
    ISSN: 1040-452X
    Keywords: Zfy ; Initial segment ; Androgen ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: XXSxr pseudomale mice (chromosomally XX animals “sex-reversed” by the Sxr factor) develop testes and produce sufficient androgens for masculinization as assessed at the macroscopic level. However, adult XXSxr pseudomales lack the epididymal initial segment (I.S.) In this study prenatal and postnatal epididymal development was examined histologically and biochemically, and it was found that XXSxr pseudomales are indistinguishable from normal XY males up to day 21 of postnatal life. By 25 days postnatally, before the onset of the pubertal androgen surge, the I.S. precursor is evident in normal animals but absent in XXSxr mutants. No major abnormalities were seen in other segments of the XXSxr epididymis. Our data suggest that androgen levels in testis and epididymis are not higher in normal XY males than in XXSxr pseudomale mice of the same age. Inadequate availability of androgens at the target site is unlikely to be the cause of the epididymal abnormality in XXSxr pseudomale mice.
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  • 2
    ISSN: 1040-452X
    Keywords: Sex determination ; Sex determining region Y ; Postmeiotic expression ; HMG box containing proteins ; Interstitial cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Although its expression in adult testis was immediately apparent, the role for Sry (sex determining region, Y) in testicular function remains elusive. We have performed transcriptional studies in an effort to elucidate potential roles of Sry by studying the time and location of its transcription in mouse testes. Northern analyses and more sensitive nuclease protection assays detected transcripts in 28-day-old testes and beyond. The highly sensitive technique of reverse transcription polymerase chain reaction (RTPCR) could not detect Sry expression in 14-day testes when primers for the most conserved portion of the gene, the high mobility group (HMG) box, were used, but primers for the circular form detected Sry transcription at all postnatal stages studied. The same HMG box primers were able to detect expression of Sry in XX, Sxra or Sxrb testes. This suggested that Sry is expressed in cells other than germ cells, which was confirmed with studies on fractionated cells - RTPCR detected transcription of Sry in the highly pure interstitial cell fraction. However, Leydig cells and a Leydig cell tumor were negative for Sry expression. We performed in situ studies in an attempt to localize the expression of Sry in the testes. Abundant expression of an Sry cross-hybridizing transcript was found in spermatogonia, in early spermatocytes, and in some interstitial cells with antisense probes to the HMG box or a more specific, 3′ region, whereas the sense probe gave little or no hybridization. It is probable that the circular transcripts, which are seen in reverse transcriptase positive (RT+) and RT- reactions by PCR because of the RT activity of Taq polymerase, are responsible for the hybridization seen in spermatogonia and spermatocytes, whereas linear and circular forms are detected later. Thus Sry is expressed in pre- and postmeiotic germ cells and in somatic cells of the testes. © 1994 Wiley-Liss, Inc.
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  • 3
    ISSN: 1040-452X
    Keywords: Collagen ; Basement membrane ; Timp ; Sexual development ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Sex-reversed (Sxr) is a duplication of the sex-determining region of the Y chromosome, which gets transposed to a paternal X chromosome. Chromosomally female (XX) zygotes that receive this XSxrchromosome develop as apparent males. Previous work on XXSxr mice (called pseudomales) showed extracellular matrix (ECM) ultrastructural abnormalities in the epididymis and testis. This study examined the biochemical nature of these abnormalities. More hydroxyproline (an indicator of collagen) was noted in the pseudomale testis and epididymis compared to normal male tissues. Western blot analysis showed increased collagen IV in the pseudomale testis and epididymis. In both the hydroxyproline and collagen IV studies, the epididymis was found to contain higher levels of these substances than the testis for both genotypes. There also appeared to be increased messenger RNA for tissue inhibitor of metalloproteinases (Timp), a regulator of collagen, in the pseudomale testis. Data from these studies seem to indicate that the XXSxr genotype influences ECM deposition and/or turnover and exerts a direct genetic influence on the development of the testis and epididymis. According to the existing paradigm of mammalian sexual development, the epididymis is expected to be normal in the presence of adequate androgenization and independent of chromosomal and genetic sex. The results presented here differ from what would be predicted by this paradigm. © 1994 Wiley-Liss, Inc.
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  • 4
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Korrosion von vorbehandeltem Aluminium nach der kathodischen ElektrotauchlackierungDie Kathodische Elektrotauchlackierung (KTL) ist seit nahezu zwei Jahrzehnten bei der industriellen Abscheidung von Grundierungen auf Stahl gut eingeführt. Epoxidharze ergeben optimale Resultate. Es besteht ein zunehmender Bedarf, dieselbe Technik für Aluminium anzuwenden, speziell für die Mischbauweise Eisen/Aluminium bei Autokarosserien. Allerdings kann dieses Metall durch die OH- -Ionen angegriffen werden, die bei der kathodischen Elektrolyse von Wasser gemäß H2O + e- → ½ H2 + OH entstehen. Die. Al2O · xH2O Schutzschicht kann sich langsam auflösen als Aluminat, und dann reagiert das Al-Metall schnell mit Wasser unter Bildung des dreifachen Volumens an Wasserstoff, wobei die oxidische Schicht wiederhergestellt wird. Demgemäß ist die Bruttoreaktion für die kathodische Korrosion des Al gegeben durch: Al + 2H2O + e- → AlO2- + 2H2.Es ist zu erwarten, daß die Änderungen an der Phasengrenze Al/AlOOH/Lack und die Akkumulation von hydrolisiertem Aluminat im Überzug unter anderem auch das Korrosionsschutzverhalten der Lackschichten beeinflussen könnten. Eine systematische Untersuchung des Einfusses von vier verschiedenen technischen Epoxidharzen von BASF Lacke & Farben AG (l)-(4) mit ihren individuellen Pigmentsystemen, wobei das eine für den Lack 3 frei von Bleisilikat war, wurde unternommen. Sieben verschiedene Aluminium (Legierungs) Substrate warden verwendet. Die Art der Vorbehandlung war in den meisten Fällen eine Zinkphosphatierung. Drei Standard-Korrosionstests für die konventionelle Korrosion (KK) und eine für Filiformkorrosion (FFK) wurden angewandt und standardmäßig ausgewertet. Der verschärfte Freibewitterungs-Korrosionstest dauerte 360 Tage.Es wurde gefunden, daß die Korrosionsschutzwirksamkeit für die KK hauptsächlich durch das Harz beeinflußt wurde, wobei sie in der folgenden Reihenfolge abnahm: \documentclass{article}\pagestyle{empty}\begin{document}$$ (4) 〉 (2) 〉 (1),\,(3). $$\end{document}Der Einfluß des Substrats war nicht sehr ausgeprägt, aber ein relatives Optimum konnte erkannt werden mit Al Mg 0.4 Si 1.2 mit Gelbchromatierung und Bonazinc 2000® und mit Al Mg 1.5 Si 0.5 Cu 4.0 mit Gelbchromatierung (mit einer Ausnahme). Die Reihenfolge der Wirksamkeit gegen die FFK änderte sich wie folgt: \documentclass{article}\pagestyle{empty}\begin{document}$$ (2) 〉 (3) 〉 〉 (1),\,(4), $$\end{document} und zinkphosphatiertes Al Mg 3 war allen anderen Substraten überlegen. Die analytisch bestimmte Geschwindigkeit der kathodischen Korrosion für unpigmentierte Lacke korrelierte nicht mit diesen Resultaten, und dies konnte indikativ sein für spezifische Pigmenteffekte. Zusammenfassend kann man sagen, daß these systematische Untersuchung auf der Basis von praktischen Systemen und Korrosionstestmethoden einen Weg aufzeigt für die Optimierung der KTL auf Aluminium.
    Notes: Cathodic deposition of paint (CDP) is Well introduced for the industrial coating of primers onto steel since nearly two decades. Epoxy resins provide optimum results. There is an increasing demand to apply the same technique for aluminium, especially for mixed constructions Fe/Al in motor car bodies. However, this metal may be attacked by the OH--ions, generated by the cathodic electrolysis of water according to: H2O + e- → ½ H2 + OH-. The Al2O3 · xH2O protecting layer may dissolve slowly as aluminate and Al-metal then reacts rapidly with water to generate the threefold volume of hydrogen under the reestablishment of the oxide layer. Thus, the overall reaction for this cathodic corrosion of Al is given by: Al + 2H2O + e- → AlO2- + 2H2.It can be foreseen, that the changes at the phase boundary Al, AlOOH/paint and the accumulation of hydrolysed aluminate in the coating may influence, among other, the corrosion protection behavior of the paint layers. A systematic study of the influence of four different industrial epoxy resins from BASF Lacks & Farben AG (1)-(4) with their individual pigment systems, the one for paint (3) to be free of lead silicate, was undertaken. Seven different aluminium (alloy) substrates were employed. Their pretreatment modes were mostly due to zincphosphatation. Three standard corrosion tests for conventional corrosion, (CC) and one for filiform corrosion (FFC) were employed and evaluated, as usual. The accelerated open air corrosion test lasted 360 days.It was found, that for CC the corrosion protection capability was predominantly influenced by the resin, and it decreased in the following order: \documentclass{article}\pagestyle{empty}\begin{document}$$ (4) 〉 (2) 〉 (1),\,(3). $$\end{document}The effect of the substrate was not very pronounced, but a relative optimum could be seen with Al Mg 0.4 Si 1.2-chromate pretreatment and Bonazinc 2000® and with Al Mg 1.5 Si 0.5 Cu 4.0-chromate pretreatment (with one exception). The ranking for FFC changed to: \documentclass{article}\pagestyle{empty}\begin{document}$$ (2) 〉 (3) 〉 〉 (1),\,(4), $$\end{document}, and zincphosphated Al Mg 3 was superior over all the other substrates. The analytically determined rate of cathodic corrosion for unpigmented paints did not correlate to these results, and this may be indicative for specific pigment effects. In conclusion, this systematic study reveals, on the basis of practical systems and corrosion test methods, a way for the optimization of CDP on aluminium.
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 7 (1986), S. 109-116 
    ISSN: 0192-253X
    Keywords: Sxr ; pseudomale ; masculinization ; Jost's principle ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: 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, wepreviously 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.
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  • 6
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 8 (1987), S. 11-15 
    ISSN: 0192-253X
    Keywords: testicular feminization ; androgen induction ; meiosis inducing substance ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The sex-linked recessive gene Tfm in the mouse produces a condition of testicular feminization (androgen insensitivity syndrome, AIS) in hemizygotes, comparable to the condition of the same name in humans. The murine mutant was originally believed to have no derivatives of the mesonephric duct system (MDS), and this absence was ascribed to dependence of these derivatives on androgens for survival. However, microscopical epi-didymides, retia testes, and vasa deferentia were identified in these animals in our laboratory. These micro-organs may play a role in meiosis induction in Tfm/Y animals. The present study was designed to determine whether survival of these organs is due to retention of an ability to respond to androgens, or whether they are unique amongst MDS derivatives in being independent of androgens.Previous studies in our laboratory demonstrated that the enzyme β-glucuronidase (βG) is androgen sensitive in the epididymis of the normal mouse. In the present investigation we used this enzyme as a marker to study androgen sensitivity in the microscopical epididymides of Tfm/Y hemizygotes and in the epididymides of control +/Y litter-mate brothers. Both mutant and control animals were studied with and without exogenous androgen stimulation.Tfm/Y hemizygotes demonstrated low levels of diffuse, cytoplasmic βG activity that appears to be unresponsive to exogenous androgen stimulation. In light of our previous studies, this distribution of βG reaction products suggests some degree of androgen sensitivity. The survival of these micro-organs and their partial androgen sensitivity may be related to the role of the MDS in inducing meiosis.
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  • 7
    ISSN: 0192-253X
    Keywords: Zinc finger Y ; sex reversed ; epididymis ; sex differentiation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The presence of the mutation Sex reversed (Sxr), a copy of a Y-chromosomal segment that gets transferred to an X chromosome, causes the resulting XXSxr mice to develop as apparent males. However, several features of male sexual development are abnormal in these animals. The testes are small and aspermatogenic, and the epididymides lack the initial segment. Testes and epididymides show abnormalities of extracellular matrix. In this study we examined transcription of the conserved Y chromosomal gene Zfy, which has an X-chromosomal homologue (Zfx). Northern blotting showed Zfy to be expressed in the testes of XXSxr animals, except for those that carry the coat-marker gene Tabby (Ta), despite the lack of germ cells in XXSxr mice. Reverse transcription polymerase chain reaction (RT-PCR) studies detected Zfy in mRNA in testes even when Ta was present. RT-PCR also demonstrated Zfy transcription in epididymides of normal males, though not in XXSxr mice. Previous authors reported an absence of Zfy transcription in XXSxr testes; Zfy transcription in normal testes has been ascribed to germ cells. Our observation indicates that this idea requires re-evaluation. The occurrence of Zfy transcription in the normal epididymis is similarly a novel finding that may help explain those aspects of epididymal development that occur in the absence of androgen. © 1994 Wiley-Liss, Inc.
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  • 8
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 9
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Peptide Synthesis in the Aqueous Phase, I.  -  Polyethyleneimine as a Water Soluble Support for the N-Carboxyanhydride MethodThe model peptide Ala-Trp-Ile (9) attached through an arginine bridge to a water soluble polyethyleneimine (1) is prepared via the N-carboxyanhydride method. The amount of arginine bound to 1 has been found to be 18 mol %. The polymer linked to the model peptide 9 can be specifically and quantitatively cleaved by trypsin into Ala-Trp-Ile-Arg (8) and 1. Further treatment of 8 with carboxypeptidase B quantitatively affords the model peptide 9 and the carboxy terminal bridging arginine (10).
    Notes: Das Modellpeptid Ala-Trp-Ile (9) wird nach der N-Carboxyanhydrid-Methode an wasserlöslichem, polymerem Äthylenimin (1), das zu 18 Mol-% mit Arginin-Brücken besetzt ist (3), synthetisiert. Mit Trypsin erfolgt spezifisch und quantitativ die Abspaltung des Ala-Trp-Ile-Arg (8) vom polymeren Träger. Durch Carboxypeptidase B wird 8 spezifisch und quantitativ zu 9 und dem ursprünglich carboxylendständigen Brücken-Arginin (10) gespalten.
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  • 10
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mass Spectrum and Vibrational Analysis of (MeSn)4S6, a Compound Analogous to AdamantaneMass spectra of the cage compounds (MeSn)4S6 and (MeSn)4Se6 are given and compared. The ionisation potential of the bond Sn—X is lowered by changing from X = S in X = Se, whereas the dissociation energy of the bond Sn—C is raised simultaneously. Shiftings of methyl groups are frequent for both compounds.IR and Raman spectra are given for (MeSn)4S6 and evaluated by means of a normal coordinate analysis based on the crystallographic parameters. The distribution of the potential energy for the normal modes in terms of internal coordinates exhibits a smaller deviation from the ideal Td symmetry than in the case of (MeSn)4Se6. The stretching force constants are f(Sn—S) = 168(1) and f(Sn—C) = 222(2) N/m. The ionic SnS44- has f(Sn—S) = 175 N/m. The values are compared with f(Sn—Se) = 154(1) und 159 N/m in the units (MeSn)4Se6 and SnSe44-.
    Notes: Die Massenspektren der Käfigverbindungen (MeSn)4S6 und (MeSn)4Se6 werden angegeben und verglichen. Erkennbar ist eine Abnahme des Ionisierungspotentials der Bindung Sn—X beim übergang von X = S zu X = Se mit gleichzeitiger Zunahme der entsprechenden Sn—C-Dissoziationsenergie. Bei beiden Verbindungen sind Methylgruppenwanderungen häufig.Für (MeSn)4S6 werden IR- und Raman-Spektren mitgeteilt und mit Hilfe einer von kristallographischen Lageparametern ausgehenden Normalkoordinatenanalyse ausgewertet. Die Verteilung der potentiellen Energien der einzelnen Normalschwingungen auf innere Koordinaten zeigt für (MeSn)4S6 eine geringere Abweichung von der idealen Td-Symmetrie als im Falle des (MeSn)4Se6. Die Valenzkraftkonstanten betragen f(Sn—S) = 168(1) und f(Sn—C) = 222(2) N/m. Im ionischen SnS44- ist f(Sn—S) mit 175 N/m nur geringfügig größer entsprechend einem analogen Befund für (MeSn)4Se6 und SnSe44- mit f(Sn—Se) = 154(1) und 159 N/m.
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