An RNA-binding motif (RBM) gene family has been identified on the human Y
chromosome that maps to the same deletion interval as the 'azoospermia
factor' (AZF). We have identified the homologous gene family (Rbm) on the
mouse Y with a view to investigating the proposal that this gene family
plays a role in spermatogenesis. At least 25 and probably >50 copies of
Rbm are present on the mouse Y chromosome short arm located between Sry and
the centromere. As in the human, a role in spermatogenesis is indicated by
a germ cell-specific pattern of expression in the testis, but there are
distinct differences in the pattern of expression between the two species.
Mice carrying the deletion Yd1, that maps to the proximal Y short arm, are
female due to a position effect resulting in non-expression of Sry ;
sex-reversing such mice with an Sry transgene produces males with a high
incidence of abnormal sperm, making this the third deletion interval on the
mouse Y that affects some aspect of spermatogenesis. Most of the copies of
Rbm map to this deletion interval, and the Yd1males have markedly reduced
Rbm expression, suggesting that RBM deficiency may be responsible for, or
contribute to, the abnormal sperm development. In man, deletion of the
functional copies of RBM is associated with meiotic arrest rather than
sperm anomalies; however, the different effects of deletion are consistent
with the differences in expression between the two species.
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A 9.7 kb segment encompassing exons 7-10 of the adrenoleukodystrophy (ALD)
locus of the X chromosome has duplicated to specific locations near the
pericentromeric regions of human chromosomes 2p11,10p11, 16p11 and 22q11.
Comparative sequence analysis reveals 92-96% nucleotide identity,
indicating that the autosomal ALD paralogs arose relatively recently during
the course of higher primate evolution (5-10 million years ago). Analysis
of sequences flanking the duplication region identifies the presence of an
unusual GCTTTTTGC repeat which may be a sequence-specific integration site
for the process of pericentromeric- directed transposition. The breakpoint
sequence and phylogenetic analysis predict a two-step transposition model,
in which a duplication from Xq28 to pericentromeric 2p11 occurred once,
followed by a rapid distribution of a larger duplicon cassette among the
pericentromeric regions. In addition to facilitating more effective
mutation detection among ALD patients, these findings provide further
insight into the molecular basis underlying a pericentromeric-directed
mechanism for non- homologous interchromosomal exchange.
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In-vitro fertilization patients (n = 15) at risk of ovarian
hyperstimulation syndrome (OHSS) (oestradiol > or =4500 pg/ml on the day
of human chorionic gonadotrophin administration and 25 or more follicles of
intermediate or large size) underwent aspiration of all follicles and
cryopreservation of all fertilized oocytes at the pronuclear stage.
Patients were monitored for up to 2 weeks post- retrieval. Subsequent
transfer of cryopreserved-thawed embryos was performed in programmed cycles
using exogenous oestrogen and progesterone for endometrial preparation. Two
patients (13%) developed OHSS necessitating hospitalization and vaginal
aspiration of ascitic fluid. Two other patients (13%) developed moderate
OHSS requiring ascitic fluid vaginal aspiration in the office setting, with
dramatic improvement of the condition. Subsequent transfer of
cryopreserved- thawed embryos yielded a clinical pregnancy rate of 58% per
transfer and ongoing or delivery rates of 42 and 67% per transfer and per
patient respectively. By eliminating pregnancy potential with
cryopreservation of all prezygotes and examining the pregnancy potential
with subsequent cryopreserved-thawed transfers, it is concluded that OHSS
is reduced, but not eliminated for patients at risk. Subsequent transfer of
cryopreserved-thawed prezygotes in a programmed cycle with exogenous
steroids yields an excellent pregnancy rate.
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Summary Arboviruses can be isolated in serially propagated cells derived from various vertebrates and invertebrates. Cell cultures can be used for direct detection of antigen by fluorescent antibody and enzyme-linked immunosorbent assays, for nucleic acid hybridization, and for visualization of viruses with electron microscopy. Reagents for enzyme-linked immunosorbent assays for IgM and IgG antibodies, hemagglutination-inhibition, complement fixation, and serum dilution-plaque reduction neutralization tests can be prepared in cell cultures infected with these viruses. Thus, cell cultures can be used as laboratory hosts for essentially all isolation, identification, and serodiagnostic procedures for arboviruses. This paper outlines current methods for diagnosis of arbovirus infections in livestock and wildlife, describes certain of these techniques, and provides references for others. 相似文献
An investigation is described of methods of isolation and purification of the high molecular weight protein (here called β2M1 globulin) which is often associated with the isoagglutinin activity of normal human serum. In the course of these experiments it was observed that ultracentrifugal concentration of this protein from serum fractions gives rise to the simultaneous concentration of two other macroglobulins (here called β2M2 and β2M3 globulins).
It was found that the concentration of β2M1 globulin in normal serum is about 25–50 mg. per 100 ml. In serum from the blood of normal donors of groups A, B and O, isohaemagglutinin activity is associated with the β2M1 globulin but probably accounts for 1 per cent or less of the total β2M1-globulin concentration in serum. This activity may represent the so-called `natural' isohaemagglutinin.
The immunological relation is discussed of the normal β2M1 globulin to certain other members of the `family' of immune globulins (γ globulin and β2A globulin) and to the pathological macroglobulins occurring in Waldenström's syndrome.
Although rabbit antibody to β2M1 globulin cross-reacts with γ globulin, suggesting that a portion of each molecule bears antigenic groupings in common, it was found that a considerable degree of β2M1-globulin specificity could be demonstrated after absorbing antisera with purified γ globulin. Attention is also drawn to the evidence that deficiency of either β2M1 globulin or γ globulin can occur independently, suggesting different cellular sources of origin.
The pathological macroglobulin demonstrable in Waldenström's syndrome is closely related immunologically to normal β2M1 globulin but is often deficient in isoagglutinin activity. This immunological relation suggests the use of specific anti-β2M1-globulin antiserum as a simple means of distinguishing macroglobulinaemia from myelomatosis or other conditions with raised levels of γ globulin.
The β2M2 and β2M3 globulins are only demonstrable in ultracentrifugal concentrates of normal serum. Evidence is presented to suggest that these proteins are nevertheless present as trace components of normal serum. The solubility and electrophoretic characteristics of these proteins resemble those of β2M1 globulin, but they can be distinguished by immunological methods from β2M1 globulin and each other. Attention is drawn to the evidence that β2M2 and β2M3 globulins may also be increased in the serum of some cases of macroglobulinaemia.
The 2362 strain of Bacillus sphaericus, which produces a binary toxin highly active against Culex mosquitoes, has been developed recently as a commercial larvicide. It is being used currently in operational mosquito control programs in several countries including Brazil, France, India, and the United States. Laboratory studies have shown that mosquitoes can develop resistance to B. sphaericus, and low levels of resistance have already been reported in field populations in Brazil, France, and India. To develop tools for resistance management, the Cyt1A protein of Bacillus thuringiensis subsp. israelensis De Barjac was evaluated for its ability to suppress resistance to B. sphaericus in a highly resistant population of Culex quinquefasciatus Say. A combination of B. sphaericus 2362 in a 10:1 ratio with a strain of B. thuringiensis subsp. israelensis that only produces Cyt1A reduced resistance by >30,000-fold. Resistance was suppressed completely when B. sphaericus was combined with purified Cyt1A crystals in a 10:1 ratio. Synergism was observed between the Cyt1A toxin and B. sphaericus against the resistant mosquito population and accounted for the marked reduction in resistance. However, no synergism was observed between the toxins against a nonresistant mosquito population. These results indicate that Cyt1A could be useful for managing resistance to B. sphaericus 2362 in Culex populations, and also provide additional evidence that Cyt1A may synergize toxicity by enhancing the binding to and insertion of toxins into the mosquito microvillar membrane. 相似文献
Primary gastric T-cell lymphomas are rare neoplasms, and all but one of the previously phenotyped cases have shown a helper-inducer phenotype. The present case is the second reported case of a primary gastric T-cell lymphoma of suppressor-cytotoxic phenotype. The tumor histology was similar to that described in some forms of node-based peripheral T-cell lymphomas. Phenotypic analysis revealed low expression of pan-T marker CD7, reduced expression of CD3, but higher density and frequency of expression of CD8 antigens that could be predicted on the basis of the pan-T markers. Natural killer cell (NK) related markers CD16, HNK-1 and NKH-1 were not expressed by the neoplastic cells. T-cell receptor (TCR) beta subunit expression was detected on fewer cells than would have been predicted on the basis of CD3 and CD8 expression, and TCR delta chain expression was undetectable. 相似文献
Insulin-like growth factor-II (IGF-II) from the invading extravillous cytotrophoblasts (EVTs) and insulin-like growth factor binding proteins (IGFBPs) from the maternal decidua interact at the feto-maternal interface and regulate implantation and placentation. To determine whether a local stimulus from the fetus is important in the regulation of IGFBP gene expression in the human decidua, we compared the expression of IGFBP genes in intra- and extrauterine (tubal) pregnancies. The expression of IGF-II and IGFBP-1 to IGFBP-6 mRNAs was determined by in-situ hybridization in the Fallopian tubes of extrauterine pregnancies and concurrent decidua (n = 6), and in the placentae and Fallopian tubes of intrauterine pregnancies (n = 6). All six IGFBP mRNAs were identified in the decidualized endometrium and decidualized Fallopian tubes of intra- and extrauterine pregnancies, with IGFBP-1 mRNA being the predominant mRNA. IGFBP-4 was the second most predominant mRNA and was slightly more abundant in the decidua of extrauterine pregnancies than of intrauterine pregnancies. IGF-II mRNA was expressed mainly in cells of fetal origin. The fact that the IGFBP mRNAs were expressed similarly in both intra- and extrauterine pregnancies indicates that the local physical stimulus from an implanting fetus is not necessary to induce or maintain decidual IGFBP gene expression. 相似文献
Manipulation of the developing nervous system has provided valuable insights into nervous system function. One important concept to arise from this type of study has been the identification of specific "critical periods" for the development of various functions. A critical period has been most clearly shown for the visual system where monocular eye closure for a few weeks led to functionally significant changes in visually guided behaviors and the connectivity of the visual cortex. Critical periods have also been defined for other sensory systems. Although studies of the effect of manipulating sensory systems during development are sometimes difficult to interpret (e.g. Ref. 7), this difficulty is compounded in the case of the motor system. Problems arise because manipulations of the postnatal motor system are difficult to implement and usually require invasive procedures such as tenotomy, neurotomy, and nerve crush (for review, see Ref. 17). We have approached the problem of manipulating the motor environment by adapting a paradigm widely used to study the experimental effects of simulated weightlessness in adult rats: namely, tail suspension. This method has several advantages for manipulating the motor system: (i) because it is noninvasive, it is less discomforting than neurotomy, tenotomy or nerve crush; (ii) it does not immobilize the animals, they move about the cage and extend and flex their hindlimbs; and (iii) it specifically examines the importance of load-bearing on the development of antigravity muscles and their neuronal circuits.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献