Administration of supraphysiological doses of testosterone to normal men
causes inhibition of spermatogenesis, but while most become azoospermic,
30-55% maintain a low rate of spermatogenesis. We have investigated whether
there are differences in endogenous androgen production, of testicular and
adrenal origin, which may be related to the degree of suppression of
spermatogenesis. Thirty-three healthy Caucasian men were given weekly i.m.
injections of 200 mg testosterone oenanthate (TE), 18 became azoospermic,
while 15 remained oligozoospermic. Urinary excretion of epitestosterone, a
specific testicular product, was reduced to <10% of pretreatment values,
with no differences between the groups. Similar results were obtained for
other markers of testicular steroidogenesis. Urinary and plasma adrenal
androgens were also reduced during TE treatment: a statistically
significant decrease in both (P < 0.001 and P < 0.05 respectively)
was seen in the azoospermic but not oligozoospermic responders. These
results suggest that testicular steroidogenesis is decreased to <10% by
the administration of supraphysiological doses of exogenous testosterone.
Differences in the degree of ongoing steroidogenesis in the testis do not
appear to account for incomplete suppression of spermatogenesis, thus
differences in androgen metabolism may underlie this heterogeneous
response. A small but significant reduction in secretion of adrenal
androgens was also detectable, the relevance of which is unclear.
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Objectives: To compare maternal characteristics and birth outcomes of Mexico-born and native-born mothers in the United States and those of North African mothers living in France and Belgium to French and Belgian nationals. Methods: We examined information from single live birth certificates for 285,371 Mexico-born and 3,131,632 U.S.-born mothers (including 2,537,264 U.S.-born White mothers) in the United States, 4,623 North African and 103,345 Belgian mothers in Belgium, and a French national random sample consisting of 632 North African and 11,185 French mothers. The outcomes were mean birthweight, low birthweight, and preterm births. Differences between native/nationals and foreign-born mothers in each country were assessed in bivariate and multivariate analyses controlling for maternal risk factors. Results: The adjusted odds for low birthweight were lower for immigrants than native/nationals by 32% in the United States, by 32% in Belgium, and by 30% in France. The adjusted odds for preterm births were lower for immigrants compared with native/nationals by 11% in the United States and by 23% in Belgium. In France, the odds for preterm births were comparable for immigrants and naturalized mothers. Infants of immigrant mothers also had higher mean birthweights in all three countries. Conclusion: Despite their disadvantaged status, Mexico-born and North African-born women residing in the United States, France, and Belgium show good birth outcomes. These cannot be explained solely by traditional risk factors. Protective factors and selective migration may offer further clues. 相似文献
Since exogenous hemin has been shown to exert a variety of stimulatory effects on erythroid cells, including the augmentation of hemoglobin synthesis, we determined its effect on early stages of erythroid development by employing clonal cells assays. The addition of hemin at a concentration of 2 X 10(-4) M to cultures of normal murine marrow substantially increased the observed number of primitive BFU-E, which was in contrast to its lack of an effect on more mature erythroid colony-forming cells. This cell-specific enhancement of primitive BFU-E resulted in marrow frequencies equivalent to or exceeding those reported in the presence of "burst-promoting activity." In the presence of hemin, the number of BFU-E was also observed to be linearly related to the number of cells plated at very low plating densities, and the cell titration curve was observed to extrapolate to the origin. The evidence suggests that hemin may be a primary growth regulator of early developmental stages of erythroid progenitor cells. 相似文献
Late-onset depression (LOD) is defined as depression manifesting for the first time in later life. Up to now, there has been no exact definition of the lower age limit for LOD. Psychopathological symptoms of LOD do not fundamentally differ from depression in other phases of life; however, cognitive deficits are typically more pronounced. The LOD is associated with an increased risk of developing dementia. Imaging studies show reduction in gray matter volume and white matter lesions caused by vascular diseases. The occurrence of depression with vascular lesions of the brain is also referred to as ”vascular depression“. The diagnostic procedure includes a detailed medical history and the observation of psychopathological changes, physical examination, laboratory tests, electroencephalograph (EEG), electrocardiograph (ECG) and magnetic resonance imaging (MRI) of the head and neuropsychological tests to measure cognitive deficits. Psychotherapy is an effective treatment option. Selective serotonin reuptake inhibitors are the first-line pharmacological therapy. 相似文献
Background: There are no FDA-approved pharmacotherapies for cannabis use disorders (CUD), despite the evaluation of numerous medications. Notably, chronic dosing of oral naltrexone decreases self-administration of cannabis in human laboratory studies.
Objectives: To test the feasibility of long-acting injectable naltrexone for the treatment of CUD, while obtaining preliminary safety and efficacy data.
Methods: Twelve adult participants (seven male) meeting DSM-IV-TR criteria for cannabis dependence enrolled into an 8-week, open-label pilot study conducted at an academic treatment research clinic. They received 380 mg intramuscular injections of long-acting naltrexone on study day 1 and at the start of study week 5. Outcome measures included percentages of study completers and participants who received the second injection, frequency of adverse events (AEs), and cannabis consumption measured by average daily grams, dollars, and using days per week as measured by timeline follow-back and urine oral delta-9-tetrahydrocannabinol (THC) concentrations.
Results: Of the 12 participants enrolled in the study, 9 completed the study and 6 received the second injection. There were no severe AEs but an unexpected AE led to the addition of supportive medications to the protocol. Number of cannabis use days per week significantly decreased over the course of the study (p = .001). Creatinine-corrected urine THC concentrations and average daily cannabis use per study week in grams and in dollars did not decrease over the course of the study.
Conclusions: Long-acting injectable naltrexone is a feasible intervention for CUD worthy of further study in a placebo-controlled, double-blinded randomized clinical trial. 相似文献
Journal of NeuroVirology - We describe two neurological cases of Oropouche virus infection in northern Brazil, where the virus is endemic but neglected as a pathogen. This study reiterates the... 相似文献
Fetal persistent middle cerebral artery reversed end diastolic flow is a rare and ominous finding. Previous cases have been associated with intracranial hemorrhage, growth restriction, anaemia, and hepatic anomaly. Intrauterine demise or early neonatal death is a common outcome. We report the case of persistent middle cerebral artery reversed end diastolic flow in a well-grown fetus at 32 weeks’ gestation resulting from acute, severe anaemia due to a large feto-maternal hemorrhage. An emergency cesarean section was performed and the neonate required advanced resuscitation and immediate blood transfusion. Postnatal magnetic resonance imaging confirmed a hemorrhagic parietal infarct and bilateral ischaemic changes in the basal ganglia. This provides further evidence that persistent middle cerebral artery reversed end diastolic flow in any fetus is an ominous finding warranting urgent diagnostic evaluation and/or delivery. 相似文献