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71.
Dunn  EK; Macchia  RJ; Solomon  NA 《Radiology》1981,139(1):175-180
The testicular scintigraphic findings of nine patients with surgically and pathologically proved torsion of the testis of over 24 hours duration are reviewed. In the delayed blood-pool images each showed the classical avascular twisted testicle with a variable peripheral rim of hyperemia. In the dynamic blood-flow phase, eight revealed a perceptible increase of vascular perfusion in the scrotal region on the affected side, in addition to the testicular radionuclide angiogram peculiarities previously described for missed testicular torsion. This pattern of perfusion was seen only in torsion of over one day duration. A low salvage probability is expected in these cases.  相似文献   
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The aims of the study were to describe course of depression in both mothers and fathers from the third trimester of pregnancy through 6 months postpartum and to examine the relationship between maternal and paternal depression. Hypotheses were as follows: (a) Depressive symptoms would be correlated between parents and (b) earlier depressive symptoms in one parent would predict later increases in depression in the other. Eighty cohabitating primiparous couples were recruited from prenatal OBGYN visits and community agencies and enrolled during pregnancy, between 28-week gestation and delivery. Participants completed measures of depression on four occasions: baseline and 1, 3, and 6 months postpartum. Ninety-eight percent of the enrolled couples (78; 156 individuals) completed the study. For both mothers and fathers, symptom severity ratings and classification as a probable case were stable across time, with prenatal depression persisting through 6 months in 75 % of mothers and 86 % of fathers. Prenatal depression in fathers predicted worsening depressive symptom severity in mothers across the first six postpartum months but not vice versa. In both expecting/new mothers and fathers, depression demonstrates a stable pattern of occurrence and symptom severity between 28-month gestation and 6 months postpartum. Although prenatal maternal depression is not predictive of symptom change in fathers, mothers with prenatally depressed partners showed significant worsening in overall symptom severity during the first six postpartum months.  相似文献   
75.
The time course of the schizophrenia auditory gating deficit may provide clues to mechanisms of impaired cognition. Magnetoencephalography was recorded during a standard paired-click paradigm. Using source strength of the M50 and M100 components for each click, calculated from dipole locations identified as underlying each component for the first click, a ratio of the second divided by the first was used to measure gating. Patients showed a left-hemisphere gating deficit in M50 and a bilateral gating deficit in M100. Hypothesizing that an early deficit may affect later processing, hierarchical regression was used to examine variance shared between the components. A left-hemisphere M100 gating deficit was coupled with the left M50 gating deficit. In contrast, a right-hemisphere M100 gating deficit was unrelated to M50 gating in either hemisphere. Investigations of interhemisphere gating relations may clarify group differences in regional connectivity and their role in gating.  相似文献   
76.
Evolutionary silencing of the human elastase I gene (ELA1)   总被引:6,自引:0,他引:6  
  相似文献   
77.
Competitive control of the self-renewing T cell repertoire   总被引:1,自引:0,他引:1  
We develop a mathematical model for the self-renewing part of the T cell repertoire. Assuming that self-renewing T cells have to be stimulated by immunogenic MHC-peptide complexes presented on the surfaces of antigen-presenting cells, we derive a model of T cell growth in which competition for MHC-peptide complexes limits T cell clone sizes and regulates the total number of self-renewing T cells in the animal. We show that for a sufficient diversity and/or degree of cross-reactivity, the total T cell number hardly depends upon the diversity of the T cell repertoire or the diversity of the set of presented peptides. Conversely, for repertoires of lower diversity and/or cross-reactivity, steady-state total T cell numbers may be limited by the diversity of the T cells. This provides a possible explanation for the limited repertoire expansion in some, but not all, mouse T cell re-constitution experiments. We suggest that the competitive interactions described by our model underlie the normal T cells numbers observed in transgenic mice, germ-free mice and various knockout mice.   相似文献   
78.
It was shown recently that mutations of the ATRX gene give rise to a severe, X-linked form of syndromal mental retardation associated with alpha thalassaemia (ATR-X syndrome). In this study, we have characterised the full-length cDNA and predicted structure of the ATRX protein. Comparative analysis shows that it is an entirely new member of the SNF2 subgroup of a superfamily of proteins with similar ATPase and helicase domains. ATRX probably acts as a regulator of gene expression. Definition of its genomic structure enabled us to identify four novel splicing defects by screening 52 affected individuals. Correlation between these and previously identified mutations with variations in the ATR-X phenotype provides insights into the pathophysiology of this disease and the normal role of the ATRX protein in vivo.   相似文献   
79.
We analysed the results of oocyte donation to women of advancedreproductive age (45 years old) and followed their pregnanciesthrough to delivery in order to assess obstetrical outcomes.Patients (n = 162) aged 45–59 years (mean ± SD;47.3 ± 3.4 years) underwent 218 consecutive attemptsto achieve pregnancy. Oocytes (16.2 ± 7.2 per retrieval)were provided by donors 35 years old. Cleaving embryos (8.2± 4.8 zygotes/couple) were transferred trans-cervically(4.5 ± 1.1 per embryo transfer) to recipients prescribedoral micronized oestradiol and intramuscular progesterone. Followingoocyte aspiration there were six instances of non-fertilization(2.8%) and 212 embryo transfers. A total of 103 pregnancieswas established for an overall pregnancy rate (PR) of 48.6%,which included 17 preclinical pregnancies, 12 spontaneous abortions,and 74 delivered pregnancies (clinical PR 40.6%; delivered PR34.9%). Multiple gestations were frequent (n = 29; 39.2% ofpregnancies) and included 20 twins, seven triplets, and twoquadruplets. Two of the triplet and both of the quadruplet pregnanciesunderwent selective reduction to twins. Antenatal complicationsoccurred in 28 women (37.8% of deliveries) and included pretermlabour (n = 9), gestational hypertension (n = 8), gestationaldiabetes (n = 6), carpel tunnel syndrome (n = 2), pre-eclampsia(n = 2), HELLP syndrome (n = 2), and fetal growth retardation(n = 2). 48 (64.8%) deliveries were by Caesa-rean section. Thegestational age at delivery for singletons was 383 ±1.3 weeks (range 35–41 weeks), with birth weight 3218± 513 g (range 1870–4775 g); twins 35.9 ±2.0 weeks (range 32–39 weeks), birth weight 2558 ±497 g (range 1700-3450 g); and triplets 33.5 ± 0.7 weeks(range 32-34 weeks), birth weight 1775 ± 190 g (range1550-2100 g). Neonatal complications (4.6% of babies born) includedgrowth retardation (n = 2), trisomy 21 (n = 1), ventricularseptal defect (n = 1), and small bowel obstruction (n = 1).There were no maternal or neonatal deaths. We conclude thatoocyte donation to women of advanced reproductive age is highlysuccessful in establishing pregnancy. However, despite carefulantenatal screening, obstetrical complications are common, oftensecondary to multiple gestation.  相似文献   
80.
Efficacy of oocytes donated by older women in an oocyte donation programme   总被引:1,自引:1,他引:1  
Population and insemination studies indicate that women experiencedeclining fertility with ageing. The question therefore ariseswhether older women are suitable oocyte donors. This study addressesthis issue by examining the relationship between oocyte donorage and clinical outcome in a large oocyte donation programme.We retrospectively reviewed data from 458 consecutive oocytedonation cycles completed by 164 different designated oocytedonors. Data were divided into two groups: group A, cycles withdonors aged 21–30 years at the time of follicular aspiration(193 cycles, 88 donors); and group B, cycles with donors aged31–40 years at the time of follicular aspiration (265cycles, 86 donors). Five donors, because of ageing during repetitivedonations, contributed data to groups A and B. In a given cycle,all oocytes for a recipient came from only one designated donor.Comparing the two donor groups, there was no difference in theamount of gonadotrophin used to achieve optimal stimulation;however, more oocytes were obtained from group A than groupB donors (16.8 ± 6.9 and 15.1 ± 8.1 respectively,P < 0.05). Similar percentages of oocytes were fertilizedin each group, resulting in the transfer of comparable numbersof embryos (4.5 ± 1.1 and 4.4 ± 13 respectively).Comparable clinical pregnancy rates were achieved (group A,36%; group B, 37%). The spontaneous abortion rates were alsosimilar (group A, 20%; group B, 12%), resulting in comparableongoing and delivered pregnancy rates per cycle (group A, 29%;group B, 32%) and per embryo transferred (group A, 6.4%; groupB, 7.3%). In conclusion, women of proven fertility should notbe excluded from donating oocytes simply because of their age.There exists a cohort of fertile women who resist the decreasingfecundity and increasing spontaneous abortion rates associatedwith ageing. With careful screening, many women of proven fertilitycan donate oocytes until the age of 40 years with an efficacyequal to that of younger women. Given the relative shortageof suitable oocyte donors, and increasing requests from recipientswith previous donor oocyte babies to obtain oocytes from thesame, now older, donor, the findings of this study are of practicalclinical importance.  相似文献   
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