Mechanical efficiency of positive work (eta+) and elastic behavior of human skeletal muscles were investigated on a special sledge apparatus which allowed the use of the normal stretch-shortening cycle exercises. Twenty-five young men were investigated in a total of 92 exercise situations, in which the intensity of the prestretch (eccentric contraction) was different, but the shortening phase (concentric contraction) was kept constant in all conditions. The results demonstrated that eta+ was on the average 35.8% +/- 6.4% and correlated positively with the prestretch intensity (r = 0.413; P less than 0.001), reaching a highest individual value of 51.5%. Estimation performed on the elastic characteristics of the leg extensor muscles confirmed an earlier suggestion that the pure muscle elasticity plays an important role in potentiating performance in stretch-shortening cycle exercises. The analysis of the myoelectrical activity of the leg extensor muscles showed that the nervous system plays an essential role in regulating muscle stiffness and thus utilization of muscle elasticity in ballistic exercises. 相似文献
PURPOSE: The purpose of this study was to retrospectively evaluate whether it is possible to decrease the risk of Molteno tube erosion through the conjunctiva by using a new technique where the silicone tube is inserted into a scleral tunnel instead of being covered only by the conjunctiva. METHODS: We reviewed Molteno implants carried out at the University Hospital of Oulu, in 332 patients who underwent traditional Molteno implantation between October 1986 and October 1998 and 92 patients who underwent surgery with the new technique between November 1998 and April 2001. RESULTS: With our former technique, conjunctival erosions occurred in 15 eyes of 15 patients (4.5%) after a median follow-up of 3.5 months (range 1-72 months); no conjunctival complications were discovered in patients who underwent surgery using the new technique during a median follow-up of 22 months (range 10-39 months). (p = 0.038, two-sample test of proportions). CONCLUSION: Inserting the Molteno tube into a scleral tunnel prevents tube extrusion through the conjunctiva in eyes with Molteno implants. The technique for making the scleral tunnel is described. 相似文献
Human cytomegalovirus (HCMV) has been reported to reshape the NK‐cell receptor (NKR) distribution, promoting an expansion of CD94/NKG2C+ NK and T cells. The role of NK cells in congenital HCMV infection is ill‐defined. Here we studied the expression of NKR (i.e., NKG2C, NKG2A, LILRB1, CD161) and the frequency of the NKG2C gene deletion in children with past congenital infection, both symptomatic (n = 15) and asymptomatic (n = 11), including as controls children with postnatal infection (n = 11) and noninfected (n = 20). The expansion of NKG2C+ NK cells in HCMV‐infected individuals appeared particularly marked and was associated with an increased number of LILRB1+ NK cells in cases with symptomatic congenital infection. Increased numbers of NKG2C+, NKG2A+, and CD161+ T cells were also associated to HCMV infection. The NKG2C deletion frequency was comparable in children with congenital HCMV infection and controls. Remarkably, the homozygous NKG2C+/+ genotype appeared associated with increased absolute numbers of NKG2C+ NK cells. Moreover, HCMV‐infected NKG2C+/+ children displayed higher absolute numbers of NKG2A+ and total NK cells than NKG2C+/? individuals. Our study provides novel insights on the impact of HCMV infection on the homeostasis of the NK‐cell compartment in children, revealing a modulatory influence of NKG2C copy number. 相似文献
The human tumor suppressor protein BRCA2 plays a key role in recombinational DNA repair. BRCA2 recruits RAD51 to sites of DNA damage through interaction with eight conserved motifs of approximately 35 amino acids, the BRC repeats; however, the specific function of each repeat remains unclear. Here, we investigated the function of the individual BRC repeats by systematically analyzing their effects on RAD51 activities. Our results reveal the existence of two categories of BRC repeats that display unique functional characteristics. One group, comprising BRC1, -2, -3, and -4, binds to free RAD51 with high affinity. The second group, comprising BRC5, -6, -7, and -8, binds to free RAD51 with low affinity but binds to the RAD51-ssDNA filament with high affinity. Each member of the first group reduces the ATPase activity of RAD51, whereas none of the BRC repeats of the second group affects this activity. Thus, through different mechanisms, both types of BRC repeats bind to and stabilize the RAD51 nucleoprotein filament on ssDNA. In addition, members of the first group limit binding of RAD51 to duplex DNA, where members of the second group do not. Only the first group enhances DNA strand exchange by RAD51. Our results suggest that the two groups of BRC repeats have differentially evolved to ensure efficient formation of a nascent RAD51 filament on ssDNA by promoting its nucleation and growth, respectively. We propose that the BRC repeats cooperate in a partially redundant but reinforcing manner to ensure a high probability of RAD51 filament formation. 相似文献
Background: Psychosocial adaptation is a measurement that represents the patient's adjustment to those changes involved in their illness. We undertook this study to search for individual characteristics and clinical aspects associated with successful psychosocial adjustment in patients with colorectal cancer (CRC) undergoing (CT) chemotherapy or chemoradiotherapy (CRT). Methods: Seventy-five patients with CRC treated with CT or CRT in a cancer center were included. Psychosocial Adjustment to Illness Scale Self-Reporting (PAIS-SR) questionnaire was used as a measurement of psychosocial adjustment. Results: Psychosocial adaptation was successful in 18 patients (24%) and unsuccessful in 57 patients (76%). Young patients, married patients and males showed lower psychosocial adaptation to disease. This is associated with the decrease in sexual relations, economic resources and psychological symptoms. Patients complained that they were unsatisfied due to the lack of disease and treatment information offered by the heath care team. Conclusions: In the process of adaptation, clinical features such as tumor location and treatment scheme are considered basic, as well as age, education, marital status. Areas such as sexuality, interpersonal and family relationships, economic status and emotional state of patients affected by the disease and treatments provide a deep complexity in the study of the psychosocial adaptation process in patients with CRC. 相似文献
Background: Macanao’s population in Venezuela has perhaps the greatest incidence of USH1B known in Latin America (79 cases per 100,000 population); however, until now no mutation in the MYO7A gene had been reported for this population.
Materials and Methods: This study aimed to evaluate the entire coding region of the MYO7A gene by direct sequencing of PCR products obtained from patients clinically diagnosed with USH1B.
Results: A novel mutation named c.6079_6081del was detected on exon 45 of the MYO7A gene, causing the loss of a single histidine amino acid at codon 2027 (p.H2027del) located within the second FERM domain of the human protein myosin VIIA. Three patients with clinical diagnosis of USH1B were detected positive in homozygosis for the c.6079_6081del mutation; whereas six people from the same affected family were heterozygotes and three other family members were negative.
Conclusion: We suggest that this new mutation named c.6079_6081del (p.H2027del) is the main cause of deaf-blindness found in this family clinically diagnosed as USH1B. Additional studies should be performed on this population to determine whether the c.6079_6081del mutation is the main cause of USH1B for the rest of the population. 相似文献