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61.
Modifications in the organization and expression of collagen genes associated with skeletal disorders. 总被引:2,自引:0,他引:2
Fibril-forming collagens represent an evolutionary related group of structurally similar molecules within the larger family of collagen proteins. Characterization of naturally occurring mutations has provided a model whereby clinically distinct phenotypes are predicted on the basis of how specific mutations alter normal fibrillogenesis. This model, originally derived from studies of type I collagen defects in osteogenesis imperfecta and Ehlers Danlos syndrome type VII, has been modified and extended by recent correlations of type II collagen defects with several chondrodysplasias and of type III collagen defects with Ehlers Danlos syndrome type IV. From analysis of the skeletal dysplasias, the pathogenic role of fibrillar collagen defects in more common clinical entities has been suggested and awaits rigorous proof. Although informative, these collective studies have revealed important exceptions to predictions of the original pathobiochemical paradigm, and, thus, they have initiated a more rigorous reconsideration of the deductive model. As an alternative, investigations are currently underway to generate transgenic mouse models of human collagenopathies. This task will not only clarify the complexity of collagen pathophysiology, but it will also permit the development of therapeutic strategies. 相似文献
62.
Semaan S Des Jarlais DC Sogolow E Johnson WD Hedges LV Ramirez G Flores SA Norman L Sweat MD Needle R 《Journal of acquired immune deficiency syndromes (1999)》2002,30(Z1):S73-S93
We examined the effectiveness of 33 U.S.-based HIV intervention studies in reducing the sexual risk behaviors of drug users by reducing unprotected sex or increasing the use of male condoms. The studies, identified as of June 1998, through the HIV/AIDS Prevention Research Synthesis project, were published in 1988 or later, measured behavioral or biologic outcomes, used experimental designs or certain quasi-experimental designs, and reported sufficient data for calculating an effect size for sexual risk reduction. Of the 33 studies, 94% recruited injection drug users; 21% recruited crack users. The mean age of participants was 36 years. Almost all studies were randomized (94%), provided another HIV intervention to the comparison groups (91%), and evaluated behavioral interventions (91%). On average, interventions were conducted in 5 sessions (total, 10 hours) during 4.5 months. Interventions compared with no interventions were strong and significant (k = 3; odds ratio [OR], 0.60; 95% confidence interval [CI], 0.43-0.85). Interventions compared with other HIV interventions showed a modest additional benefit (k = 30; OR, 0.91; 95% CI, 0.81-1.03). When we extrapolated our result (an OR of 0.60) to a population with a 72% prevalence of risk behavior, the proportion of drug users who reduced their risk behaviors was 12.6% greater in the intervention groups than in the comparison groups. Our meta-analysis shows that interventions can lead to sexual risk reduction among drug users and justifies providing interventions to drug users. Developing interventions with stronger effects to further reduce sexual risk behaviors among drug users must remain a high priority. 相似文献
63.
64.
Antiphospholipid antibodies and the outcome of pregnancy after the first in-vitro fertilization and embryo transfer cycle 总被引:1,自引:1,他引:1
Balasch J; Creus M; Fabregues F; Civico S; Reverter JC; Carmona F; Tassies D; Vanrell JA 《Human reproduction (Oxford, England)》1998,13(5):1180-1183
Increased antiphospholipid antibody prevalence has been demonstrated by a
number of recent studies in in-vitro fertilization (IVF) patients but the
potential effects of antiphospholipid antibodies on the different
components of the reproductive process and the consideration of whether to
test IVF patients for antiphospholipid antibodies are controversial. The
present study was undertaken to investigate the possible association
between the presence of circulating antiphospholipid antibodies (namely the
lupus anticoagulant and anticardiolipin antibodies), among a series of 21
consecutive IVF patients having a clinical spontaneous abortion after their
first embryo transfer. As a control group (n=42), the nearest IVF cycle
resulting in an ongoing pregnancy before and after each miscarried IVF
cycle (i.e. the closest cycles in temporal relationship to the index cycle)
was used. One patient (4.8%) in the study group and two women (4.8%) among
controls were seropositive for antiphospholipid antibodies. These low and
similar seropositivity rates found in the two groups studied lead us to
conclude that antiphospholipid antibodies testing in IVF patients should be
considered only in those women having repeated failures of
implantation/clinical abortion after embryo transfer but not in an
infertile general population reaching an IVF programme.
相似文献
65.
Huisman JA; Paulussen RJ; Geurts TB; Odink J; Rekers H 《Human reproduction (Oxford, England)》1997,12(1):34-38
The objective was to demonstrate bioequivalence between s.c. and i.m.
administration of Humegon (FSH/LH ratio 1:1) and Normegon (FSH/LH ratio
3:1). In two randomized, single-centre, cross-over studies, 18 healthy
volunteers on each formulation were assigned to one of the two
administration sequences. Subjects were given single doses of one of the
above gonadotrophins after endogenous gonadotrophin production had first
been suppressed using high-dose oral contraceptive. Subsequently, rate
(Cmax, tmax) and extent (AUC) of absorption of follicle stimulating hormone
(FSH) and luteinizing hormone (LH) were determined for 14 days. For Cmax
and AUC, analysis of variance (ANOVA) was performed on log-transformed data
and for tmax ANOVA was performed on ranks. Intramuscular and s.c.
injections of Humegon were bioequivalent with respect to the main
pharmacokinetic parameters, being AUC and Cmax of FSH absorption.
Intramuscular and s.c. injections of Normegon were bioequivalent with
respect to the AUC of FSH and not bioequivalent with respect to the Cmax of
FSH. For tmax of FSH as well as for most LH variables of both preparations,
bioequivalence could not be proven due to the high intra- and
interindividual variability and/or concentrations being close to the
detection limit. Thus, the main pharmacokinetic FSH variables after i.m.
and s.c. administration of Humegon and Normegon were bioequivalent.
相似文献
66.
Is the outcome of in-vitro fertilization and embryo transfer treatment improved by spontaneous or surgical drainage of a hydrosalpinx? 总被引:4,自引:7,他引:4
Sowter MC; Akande VA; Williams JA; Hull MG 《Human reproduction (Oxford, England)》1997,12(10):2147-2150
A pilot study was designed to examine whether the outcome of embryo
transfer in women with a hydrosalpinx might be improved by surgical
drainage of the hydrosalpinx at the time of oocyte collection for in- vitro
fertilization treatment. A comparative, controlled but retrospective
analysis of the results was performed of all women with infective tubal
damage aged <40 years old, who had ovulatory cycles, a normal uterus and
a partner with normal spermatozoa. A standardized treatment regimen was
used. A maximum of three embryos were transferred. Hydrosalpinx was defined
by prior hysterosalpingography and/or laparoscopy with transcervical dye
injection. A total of 237 embryo transfer cycles in women with
hydrosalpinges (tubal distension not visible in 151, visible but not
drained in 30 and drained in 56) were compared with 705 embryo transfer
cycles in women with tubal disease but no hydrosalpinx. Results were
analysed in the first three cycles but also separately in the first cycle
to check for bias. Success rates were higher in the first cycle, but did
not significantly influence overall differences. Implantation rates were
significantly reduced overall in the hydrosalpinx group (8.0 versus 13.2%
for controls; P < 0.001), being 8.3% (P < 0.01) in the subgroup
without evident tubal distension and 7.5% (not significant) in the drained
hydrosalpinx group. This study shows that tubal damage with distal
occlusion is associated with a marked reduction in embryo implantation,
even in the absence of obvious fluid distension. Surgical drainage of
distended hydrosalpinges appears to offer no benefit.
相似文献
67.
68.
Repeated measurements of body composition and subcutaneous fat distribution were obtained in female gymnasts to test the hypothesis of a selective response from localized fat deposits to intense physical training. Repeated measurements were obtained on the members of three nationally ranked collegiate gymnastic teams: at the beginning and peak of the training season. The highest ranked team was measured a third time, three weeks after the end of the competitive season. Body composition was estimated using anthropometry and bioelectric impedance; subcutaneous fat thickness was measured using skinfold calipers and ultrasound images of adipose tissue thickness (ATT). The mean difference between baseline and peak measurements were statistically significant (P ? .05) for the triceps and suprailiac skinfolds, and for the adipose tissue thickness at the suprailiac and hypogastric sites. There were no significant changes in weight, percentage of body fat, circumferences, or subcutaneous fat thickness at the subscapular, calf or medial thigh sites. In the team with three sets of measurements, only the triceps skinfold and the suprailiac ATT showed a statistically significant effect of training. © 1993 Wiley-Liss, Inc. 相似文献
69.
KM Kanal NJ Hangiandreou AM Sykes HE Eklund PA Araoz JA Leon BJ Erickson 《Journal of digital imaging》2002,14(1):30-37
The aims of this work were to measure the accuracy of one continuous speech recognition product and dependence on the speaker's
gender and status as a native or nonnative English speaker, and evaluate the product's potential for routine use in transcribing
radiology reports. IBM MedSpeak/Radiology software, version 1.1 was evaluated by 6 speakers. Two were nonnative English speakers,
and 3 were men. Each speaker dictated a set of 12 reports. The reports included neurologic and body imaging examinations performed
with 6 different modalities. The dictated and original report texts were compared, and error rates for overall, significant,
and subtle significant errors were computed. Error rate dependence on modality, native English speaker status, and gender
were evaluated by performing ttests. The overall error rate was 10.3 +/- 3.3%. No difference in accuracy between men and women
was found; however, significant differences were seen for overall and significant errors when comparing native and nonnative
English speakers (P = .009 and P = .008, respectively). The speech recognition software is approximately 90% accurate, and
while practical implementation issues (rather than accuracy) currently limit routine use of this product throughout a radiology
practice, application in niche areas such as the emergency room currently is being pursued. This methodology provides a convenient
way to compare the initial accuracy of different speech recognition products, and changes in accuracy over time, in a detailed
and sensitive manner. 相似文献
70.
The role of the microtubules in tumor necrosis factor-alpha-induced endothelial cell permeability 总被引:8,自引:0,他引:8
Petrache I Birukova A Ramirez SI Garcia JG Verin AD 《American journal of respiratory cell and molecular biology》2003,28(5):574-581
Tumor necrosis factor (TNF)-alpha, a major proinflammatory cytokine, triggers endothelial cell activation and barrier dysfunction which are implicated in the pathogenesis of pulmonary edema associated with acute lung injury syndromes. The mechanisms of TNF-alpha-induced vascular permeability are not completely understood. Our initial experiments demonstrated that TNF-alpha-induced decreases in transendothelial electrical resistance across human pulmonary artery endothelial cells are independent of myosin light chain phosphorylation catalyzed by either myosin light chain kinase or Rho kinase. We next assessed the involvement of another cytoskeletal component, the tubulin-based microtubule network, and found TNF-alpha to induce a decrease in stable tubulin content and partial dissolution of peripheral microtubule network as evidenced by anti-acetylated tubulin and anti-beta-tubulin immunofluorescent staining, respectively. Microtubule-stabilizing agents, paclitaxel and epothilone B, significantly attenuated TNF-alpha-induced decreases in transendothelial electrical resistance, inhibited the cytokine-induced increases in actin stress fibers, formation of intercellular gap, and restored the TNF-alpha-compromised vascular endothelial (VE)-cadherin-based cell-cell junctions. Importantly, neither TNF-alpha nor paclitaxel treatment was associated with endothelial cell apoptosis. Inhibition of p38 mitogen-activated protein kinase by SB203580 significantly attenuated TNF-alpha-induced microtubule destabilization, actin rearrangement, and endothelial barrier dysfunction. These results strongly suggest the involvement of microtubule rearrangement in TNF-alpha-induced endothelial cell permeability via p38 mitogen-activated protein kinase activation. 相似文献