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41.
Duncan WC; Illingworth PJ; Young FM; Fraser HM 《Human reproduction (Oxford, England)》1998,13(9):2532-2540
The molecular mechanisms involved in luteolysis are still unclear in the
primate. This study aimed to investigate the effect of induced luteolysis
on the ovarian luteinizing hormone (LH) receptor and the steroidogenic
enzyme, 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in the marmoset
monkey. Luteolysis was induced in the mid-luteal phase either directly by
systemic prostaglandin F2alpha (PGF2alpha), or indirectly by LH withdrawal
using systemic gonadotrophin releasing hormone antagonist (GnRHant)
treatment. The LH receptor was studied by isotopic mRNA in-situ
hybridization and in-situ ligand binding and 3beta-HSD expression was
studied using isotopic mRNA in-situ hybridization and immunohistochemistry.
Induced luteolysis was associated with a reduction in the expression of LH
receptor (P < 0.0001) and 3beta-HSD mRNA, closely followed by a
reduction in the LH receptor (P < 0.05) and 3beta-HSD protein
concentrations within 24 h. There were no differences in the findings
whether luteolysis was induced with PGF2alpha or GnRHant. This study shows
that disparate mechanisms to induce luteolysis in the primate result in an
identical rapid loss of the LH receptor and 3beta-HSD. In conclusion,
induced luteolysis leads to rapid loss of the steroidogenic pathway in
luteal cells.
相似文献
42.
Hendrickx J; Dams E; Coucke P; Lee P; Fernandes J; Willems PJ 《Human molecular genetics》1996,5(5):649-652
X-linked liver glycogenosis type II (XLG II) is a recently described X-
linked liver glycogen storage disease, mainly characterized by enlarged
liver and growth retardation. These clinical symptoms are very similar to
those of XLG I. In contrast to XLG I patients, however, XLG II patients do
not show an in vitro enzymatic deficiency of phosphorylase kinase (PHK).
Recently, mutations were identified in the gene encoding the liver alpha
subunit of PHK (PHKA2) in XLG I patients. We have now studied the PHKA2
gene of four unrelated XLG II patients and identified four different
mutations in the open reading frame, including a deletion of three
nucleotides, an insertion of six nucleotides and two missense mutations.
These results indicate that XLG II is due to mutations in PHKA2. In
contrast to XLG I, XLG II is caused by mutations that lead to minor
structural abnormalities in the primary structure of the liver alpha
subunit of PHK. These mutations are found in a conserved RXX(X)T motif,
resembling known phosphorylation sites that might be involved in the
regulation of PHK. These findings might explain why the in vitro PHK
enzymatic activity is not deficient in XLG II, whereas it is in XLG I.
相似文献
43.
44.
C L Roberts C Morin D G Addiss S P Wahlquist P A Mshar J L Hadler 《Journal of clinical microbiology》1996,34(9):2292-2293
To describe patterns of testing for Cryptosporidium oocysts in stool samples, Connecticut laboratories were surveyed. Different detection methods were used. Most laboratories examined stools specifically for Cryptosporidium only on physician request. The rate of positive tests varted widely (0 to 28%). Higher rates of positivity were associated with the use of monoclonal antibody methods, the use of two or more staining procedures, and testing of stool specimens in addition to those requested by physicians. 相似文献
45.
46.
Morin J Faideau B Gagnerault MC Lepault F Boitard C Boudaly S 《Clinical and experimental immunology》2003,134(3):388-395
CD11c+/CD11b+dendritic cells (DC) with high levels of major histocompatibility complex (MHC) class II and co-stimulatory molecules have been derived from spleen cells cultured with granulocyte-macrophage colony stimulating factor (GM-CSF) + flt-3L + interleukin (IL)-6 (flt-3L-DC). Investigating in vivo the function of DC in non-obese diabetic mice (NOD), we showed that a single injection of this in vitro-derived subset of DC prevents the development of diabetes into prediabetic female mice. In contrast, DC derived from bone marrow cells cultured with GM-CSF + IL-4 [bone marrow (BM)-DC] induced no protection. Moreover, protection against diabetes following injection of flt-3L-DC was associated with IL-4 and IL-10 production in the spleen and the pancreatic lymph nodes of recipient mice, indicating that this DC population is able to polarize the immune response towards a Th2 pathway. As we shown previously, NOD BM-DC exhibit an enhanced capacity to produce IL-12p70 in response to lipopolysaccharide (LPS) and anti-CD40 stimulation compared to BM-DC from control mice. In contrast, NOD flt-3L-DC, as their control mouse counterpart, produced no IL-12p70 to these stimuli. Our findings show that a subset of DC, characterized by a mature phenotype and the absence of IL-12p70 production can be derived from NOD mouse spleen favouring IL-4 and IL-10 regulatory responses and protection from diabetes development. 相似文献
47.
A novel gene that encodes a protein with a putative src homology 3 domain is a candidate gene for familial juvenile nephronophthisis 总被引:3,自引:0,他引:3
48.
49.
A fish encephalitis virus that differs from other nodaviruses by its capsid protein processing 总被引:6,自引:0,他引:6
Summary. RNA2, the short segment of the genome of Dicenthrarchus labrax encephalitis virus (DIEV), a fish nodavirus causing seabass encephalitis, was cloned. Sequence analysis revealed that DIEV
RNA2 contains a single open reading frame (ORF), which carries the catalytic D-75 residue but lacks the site for autocatalytic
proteolysis, the process yielding the two capsid proteins of insect nodaviruses. Nevertheless, SDS-PAGE analysis of mature
virions revealed a 43–45 kDa protein doublet. In order to determine the mechanism of synthesis of the two capsid proteins
in DIEV, wild type and mutagenized forms of RNA2 were expressed in cell-free translation extracts and in transfected cells.
Results showed that, despite the presence of the catalytic D-75 residue, the DIEV capsid protein doublet did not result from
the assembly-dependent autocatalytic cleavage of a protein precursor. Moreover, our data show that, although suggested by
sequence analysis, the DIEV capsid protein doublet results from neither an alternative initiation codon usage nor from a −1
ribosomal frameshift. Results of cell-free translation experiments demonstrate that the capsid protein doublet neither results
of the proteolytic cleavage of a precursor nor of a degradation process. Kinetics of capsid protein synthesis in cell-free
translation programmed with RNA2 revealed, instead, that the two capsid proteins are cosynthesized. Together these data strongly
suggest that the DIEV capsid protein doublet results from cotranslational modification(s) of the ORF-encoded protein.
Accepted July 31, 1997 Received May 26, 1997 相似文献
50.
Chronic cocaine exposure during critical periods of development induces short- and long-term effects. During the pubertal period, the hypothalamic–pituitary–gonadal (HPG) axis undergoes many dynamic changes. The present study investigated whether chronic periadolescent cocaine alters reproductive maturity in the rat. Sixty female Long–Evans hooded rats were randomly assigned to one of three conditions (20 mg cocaine/kg/day, saline injected and uninjected), for dosing from postnatal day 21 (P21) through P60. Several indicators of reproductive maturation and functioning were assessed during and following treatment. Cocaine exposure had no effect on the onset of puberty or on the date of first ovulation. The number of proestrus–estrus transitions was significantly lower in cocaine-exposed females compared to uninjected females, but not compared to saline-injected controls. This reduction was observed during exposure to cocaine, as well as after the cessation of injections. During the dosing period, cocaine-exposed rats also exhibited a greater number of cycles that had no clear P–E transition than did UN subjects; this effect disappeared once injections stopped. These alterations suggest immediate, and possibly persisting, alterations in the control of ovulation after chronic cocaine exposure throughout adolescence. Interestingly, during the injection period, the saline-injected females had a significantly greater number of diestrus days compared to uninjected and cocaine-injected animals, as well as a lower proportion of regular 4- and 5-day cycles. These differences disappeared once injections stopped. These results suggest a stress-induced irregularity of the estrous cycle, possibly attenuated by cocaine and recoverable after exposure. The present findings indicate that the HPG axis is susceptible to short-term, and possibly to long-term, alterations induced by cocaine exposure throughout the adolescent period. 相似文献