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941.
A patient with a mitotically unstable dic(Y)(p11) chromosome is reported. Physical examination revealed a small penis with severe hypospadia, undescended testes, rudimetary vagina, uterus, left fallopian tube, and no stigmata of Turner syndrome. Longitudinal chromosome studies over a four-year period, including blood, skin, foreskin, and testicular tissue, revealed 45,X/46,X,dic(Y)(p11)/46,X,del(dic Y) mosaicism. The proportions of these cells varied in the different tissues, and only 45,X and 46,X,del(dic Y) were major cell lines in testicular tissue. Additional minor cell lines were present mainly in peripheral blood: 47,X,dicY,dicY; 47,X,dicY,del(dicY); and 47,X,del(dicY),del(DICY). Premature disjunction of one of the centromeres in a high percentage of the dicentric Y chromosomes in metaphase was observed by Q- and C-banding. Lymphocytes at anaphase and telophase showed lagging Y chromosomes, fragments, and nondisjunction. These observations indicate a high degree of mitotic instability and thus raise the question of the effect of premature centromeric disjunction on mitotic instability of dicentric chromosomes.  相似文献   
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945.
Shallow groundwater currently represents the main source for water supply in Kabul. Detailed information on the hydrogeology of the Kabul basin is therefore needed to improve the supply situation and to develop sustainable concepts of groundwater use. The basin is situated at the intersection of three major fault systems and comprises three major aquifers, all consisting of coarse sandy to gravely material originating from the surrounding mountains. The aquifers were deposited by several rivers draining the basin. Marl is the basal layer of the aquifers. Usually the aquifers are covered by loess loams which are an important feature in groundwater protection. The coarse aquifer material has high permeability. Deeper parts are affected by cementation of pore spaces, resulting in formation of semi-diagenetic conglomerates which decrease well yields. The main groundwater recharge occurs after the snowmelt from direct exfiltration from the rivers and from foothill infiltration. The high withdrawals of the last few years and a steadily rising population have led to a strong overexploitation of the groundwater resource as indicated by falling groundwater levels and deteriorating groundwater quality.  相似文献   
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STUDY OBJECTIVE: To arrive at a consensus on the priorities for future research in emergency medical services for children. METHODS: A consensus group was convened using the Rand-UCLA Consensus Process. The group took part in a 3-phase process. Round 1 involved reviewing a compendium of relevant research articles and answering a mailed questionnaire. Panel members were asked to prioritize topics on the basis of the 1993 Institute of Medicine Report on Emergency Medical Services for Children. Participants were asked to rate each topic based on the significance of the research, and whether the topic would (1) improve general knowledge, (2) change behavior, (3) improve health, (4) decrease the cost of care, or (5) change public policy. A 4-point Likert scale was used. Participants were also asked if the research would require a multicenter study and if the research were feasible. Round 2 of the study involved a meeting of the panel, where the results of Round 1 were discussed and the topics were reprioritized. The topics were given a rank order and a final ranking was done in Round 3. RESULTS: The panel considered a list of 32 topics; these were combined and reworded to give them more precise meaning. Several new topics were also added. Fifteen topics were given a rank order and placed within the 7 broad categories of the Institute of Medicine report. Clinical aspects of emergency care, systems organization, configuration, and operation and injury prevention were given high priority rankings. The first 5 topics were very close in point-rank order. CONCLUSION: The panel was able to develop a list of important topics for future research in emergency medical services for children that can be used by foundations, governmental agencies, and others in setting a research agenda for such services.  相似文献   
948.
We report two cases of tricuspid valve replacement for tricuspid valve insufficiency as reoperations following mitral valve replacement through midline sternotomy. A right thoracotomy was used to approach the tricuspid valve. To avoid the risk of cardiac laceration, cardiopulmonary bypass was instituted after cannulation of the femoral artery and of superior vena cava through right atrium with balloon caval occlusion and inferior vena cava through the femoral vein with balloon caval occlusion. Without aortic cross clamping under mild hypothermia, right atriotomy was performed through adherent parietal pleura, pericardium, and right atrial wall without dissection. Tricuspid valve was replaced utilizing the bioprosthetic valve with good clinical results. These new measures were expeditiously carried out without dissection of the heart, which has been deemed to be the risk of reoperations.  相似文献   
949.
Increased bone turnover has been suggested as a potential risk factor for osteoporotic fractures. We investigated this hypothesis in a prospective cohort study performed on 7598 healthy women more than 75 years of age. One hundred and twenty-six women (mean years 82.5) who sustained a hip fracture during a mean 22-month follow-up were age-matched with three controls who did not fracture. Baseline samples were collected prior to fracture for the measurement of two markers of bone formation and three urinary markers of bone resorption: type I collagen cross-linked N- (NTX) or C-telopeptide (CTX) and free deoxypyridinoline (free D-Pyr). Elderly women had increased bone formation and resorption compared with healthy premenopausal women. Urinary excretion of CTX and free D-Pyr, but not other markers, was higher in patients with hip fracture than in age-matched controls (p = 0.02 and 0.005, respectively). CTX and free D-Pyr excretion above the upper limit of the premenopausal range was associated with an increased hip fracture risk with an odds ratio (95% confidence interval) of 2.2 (1.3-3.6) and 1.9 (1.1-3.2), respectively, while markers of formation were not. Increased bone resorption predicted hip fracture independently of bone mass, i.e., after adjustment for femoral neck bone mineral density (BMD) and independently of mobility status assessed by the gait speed. Women with both a femoral BMD value of 2.5 SD or more below the mean of young adults and either high CTX or high free D-Pyr levels were at greater risk of hip fracture, with an odds ratio of 4.8 and 4.1, respectively, than those with only low BMD or high bone resorption. Elderly women are characterized by increased bone turnover, and some markers of bone resorption predict the subsequent risk of hip fracture independently of hip BMD. Combining the measurement of BMD and bone resorption may be useful to improve the assessment of the risk of hip fracture in elderly women.  相似文献   
950.
We used stimulus-triggered averaging (StTA) of electromyographic (EMG) activity to investigate two major questions concerning the functional organization of the magnocellular red nucleus (RNm) for reaching movements in the macaque monkey. The first is whether the clear preference toward facilitation of extensor muscles we have reported in previous studies for distal (wrist and digit) forelimb muscles also exists for proximal muscles (shoulder and elbow). The second question is whether distal and proximal muscles may be cofacilitated from RNm suggesting the representation of functional muscle synergies for coordinated reaching movements. Two monkeys were trained to perform a prehension task requiring multijoint coordination of the forelimb. EMG activity was recorded from 24 forelimb muscles including 5 shoulder, 7 elbow, 5 wrist, 5 digit, and 2 intrinsic hand muscles. Microstimulation (20 microA at 20 Hz) was delivered throughout the movement task. From 137 microstimulation sites in the RNm, a total of 977 poststimulus effects was obtained including 733 poststimulus facilitation effects (PStF) and 244 poststimulus suppression effects (PStS). Of the PStF effects, 58% were obtained from distal muscles; 42% from proximal muscles. Digit muscles were more frequently facilitated (35%) than the wrist, elbow, or shoulder muscles (20, 24, and 18%, respectively). The intrinsic hand muscles were infrequently facilitated (3%). At all joints tested, PStF was more common in extensor muscles than flexor muscles. This extensor preference was very strong for shoulder (85%), wrist (85%), and digit muscles (94%) and weaker for elbow muscles (60%). Of the PStS effects, 65% were in distal muscles and 35% in proximal muscles. Interestingly, the flexor muscles were more frequently inhibited from RNm than extensor muscles. At 72% of stimulation sites, at least two muscles were facilitated. The majority of these sites (61%) cofacilitated both proximal and distal muscles. At the remaining sites (39%), PStF was observed in either the proximal (17%) or distal muscles (22%). Facilitation most often involved combinations of shoulder, elbow, and distal muscles (30%) or shoulder and distal muscles (26%). Only rarely were intrinsic hand muscles part of the total muscle synergy. Our results show that the RNm 1) controls both proximal and distal muscles but the strength of influence is biased toward distal muscles, 2) preferentially controls extensor muscles not only at distal forelimb joints but also at proximal joints, and 3) output zones cofacilitate synergies of proximal and distal muscles involved in the control of forelimb reaching movements.  相似文献   
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