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991.
Cystic fibrosis as a cause of infertility   总被引:2,自引:0,他引:2  
Cystic fibrosis (CF) is one of the autosomal recessive diseases, caused by mutations in a gene known as cystic fibrosis transmembrane regulator (CFTR). The majority of adult males with CF (99%) is characterized by congenital bilateral absence of vas deferens (CBAVD). CBAVD is encountered in 1-2% of infertile males without CF. Females with CF are found to be less fertile than normal healthy women. In females with CF, delayed puberty and amenorrhoea are common due to malnutrition. CFTR mutations are also associated with congenital absence of the uterus and vagina (CAUV). The National Institutes of Health recommend genetic counseling for any couple seeking assisted reproductive techniques with a CF male or obstructive azoospermia which is positive for a CF mutation.  相似文献   
992.
The aim of this study was to investigate the effect of providing a supplement containing polyunsaturated fatty acids and antioxidants (PROSPERM) on the biochemical characteristics of boar semen. Two sexually mature boars were fed a standard diet with PROSPERM (250 g daily) for a 24-week period. Ejaculates collected prior to supplementation were used as the control. Semen quality and biochemical parameters were analyzed. The dietary supplementation enhanced sperm characteristics, including the percentage of spermatozoa with intact plasma membrane and osmotic resistance of the acrosomal membrane. Higher production of malondialdehyde was concurrent with increased activity of superoxide dismutase in the seminal plasma and spermatozoa after 8 weeks of supplementation. These changes were accompanied by a high content of total protein and low-molecular antioxidants of the seminal plasma. It was observed that PROSPERM supplementation enhanced the survivability of boar spermatozoa during storage in a standard semen extender supplemented with lipoprotein fractions, isolated from hen egg yolk or ostrich egg yolk, at 5 degrees C and 16 degrees C. These results indicate that PROSPERM supplementation of boars had a beneficial effect on the biological characteristics of the spermatozoa, which could be useful for semen preservation at different temperatures.  相似文献   
993.
Previous reports have found that non-Jewish Americans with ancestry from Ireland have an increased frequency of heterozygosity for Tay-Sachs disease (TSD), although frequency estimates are substantially different. Our goal in this study was to determine the frequency of heterozygosity for TSD and Sandhoff diseases (SD) among Irish Americans, as well as in persons of English, Scottish, and/or Welsh ancestry and in individuals with Italian heritage, who were referred for determination of their heterozygosity status and who had no known family history of TSD or SD or of heterozygosity for these conditions. Of 610 nonpregnant subjects with Irish background, 24 TSD heterozygotes were identified by biochemical testing, corresponding to a heterozygote frequency of 1 in 25 (4%; 95% CI, 1/39-1/17). In comparison, of 322 nonpregnant individuals with ancestry from England, Scotland, or Wales, two TSD heterozygotes were identified (1 in 161 or 0.62%; 95% CI, 1/328-1/45), and three TSD heterozygotes were ascertained from 436 nonpregnant individuals with Italian heritage (1 in 145 or 0.69%; 95% CI, 1/714-1/50). Samples from 21 Irish heterozygotes were analyzed for HEXA gene mutations. Two (9.5%) Irish heterozygotes had the lethal + 1 IVS-9 G --> A mutation, whereas 9 (42.8%) had a benign pseudodeficiency mutation. No mutation was found in 10 (47.6%) heterozygotes. These data allow for a frequency estimate of deleterious alleles for TSD among Irish Americans of 1 in 305 (95% CI, 1/2517-1/85) to 1 in 41 (95% CI, 1/72-1/35), depending on whether one, respectively, excludes or includes enzyme-defined heterozygotes lacking a defined deleterious mutation. Pseudodeficiency mutations were identified in both of the heterozygotes with ancestry from other countries in the British Isles, suggesting that individuals with ancestry from these countries do not have an increased rate of TSD heterozygosity. Four SD heterozygotes were found among individuals of Italian descent, a frequency of 1 in 109 (0.92%; 95% CI, 1/400-1/43). This frequency was higher than those for other populations, including those with Irish (1 in 305 or 0.33%; 95% CI, 1/252-1/85), English, Scottish, or Welsh (1 in 161 or 0.62%; 95% CI, 1/1328-1/45), or Ashkenazi Jewish (1 in 281 or 0.36%; 95% CI, 1/1361-1/96) ancestry. Individuals of Irish or Italian heritage might benefit from genetic counseling for TSD and SD, respectively.  相似文献   
994.
The aim of this study was to determine the incidence of Candida spp. strains in specimens obtained from surgically treated patients as well as to analyze the accompanying bacterial flora, both aerobic and anaerobic. The material came from two groups of patients. In the first group consisting of patients operated for colon and rectum carcinoma, the samples included peritoneal fluid, colon or rectum bioptates, pus, blood, and wound swabs. In the other group, biopsy material and smears from post operation wounds were taken from patients who underwent a surgical treatment of larynx carcinoma. Altogether, 282 various clinical specimens from 165 patients were analysed, and 41 Candida spp. strains were isolated: 39 strains of C. albicans and 2 strains of C. tropicalis. In 20 out of 41 specimens infected with Candida spp. (48.8%) the co-infection with bacterial aerobic flora was found. In 10 cases (24.4%), the fungi were isolated together with aerobic and anaerobic bacterial flora, whereas in 2 specimens (4.9%) the anaerobes and Candida albicans were diagnosed. The remaining 9 samples showed only the presence of Candida spp. (21.9%). From among aerobic bacterial flora Enterococcus spp. strains (n = 17) and Gram negative rods from Enterobacteriaceae family (n = 13) were the most frequently isolated. The bacterial strains of Streptococcus spp. (n = 5), Pseudomonas spp. (n = 3), Staphylococcus spp. and Corynebacterium spp. (2 strains, both) were identified more rarely. Bacteroides spp. were the most frequent members of bacterial anaerobic flora (n = 10). Other isolated anaerobic bacteria were classified as Fusobacterium spp. or Peptostreptococcus spp. (1 strain each). E. coli and Enterococcus spp. strains of aerobic bacterial flora were more frequently isolated together with Candida spp. CONCLUSIONS: (i) Mixed bacterial flora was found to predominate in the clinical material from the patients after surgery. (ii) Candida spp. were most frequently found together with aerobic bacterial flora.  相似文献   
995.
Radical scavenging properties of genistein   总被引:20,自引:0,他引:20  
The reactivity of genistein toward reactive radical species has been investigated by means of pulse radiolysis. The values of rate constants, respectively 2.3 x 10(10) M(-1)s(-1) and 1.3 x 10(10) M(-1)s(-1) for the reaction with hydroxyl radical at pH 8.3 and 3.0, are close to diffusion limit indicating that genistein is a potent hydroxyl radical scavenger. The reactivity of genistein towards one-electron oxidants has also been investigated. The rate constants k = 4.6 x 10(9) M(-1)s(-1) (pH 8.3) and 6.7 x 10(8) M(-1)s(-1) (pH 7.6) have been determined for the reaction of genistein with *N3 and Br2*- radicals, respectively. For both oxidants the rate constants at pH 3 does not exceed 10(8) M(-1)s(-1). The differences in reactivity of genistein towards the oxidants at different acidity of the solution have been assumed to arise from the acid-base equilibria of genistein. The dissociation constants for genistein (pKa: 7.2, 10.0, and 13.1) have been evaluated spectroscopically. The influence of acid-base equilibria on bond dissociation energy and ionization potential for genistein has also been investigated by means of DFT calculations. It has been concluded on the basis of these calculations that monoanionic form of genistein existing at physiological pH is more powerful radical scavenger than the neutral molecule.  相似文献   
996.
997.
Ab initio techniques were used to determine the effects of protonation and methylation on cytosine's molecular geometry, molecular affinities, relative stability, and structural rigidity. The geometries of local minima were fully optimized by the gradient procedure at DFT and MP2 levels of theory with the medium size 6-31G(d,p) basis set. The results of energetic analysis indicate that N(3)-methyl-cytosine and C(5)-methyl-cytosine are the most stable derivatives for monocationic and neutral species, respectively. The structural rigidity of each species was assessed by an analysis of normal out-of-plane frequencies, the amplitudes, and by the contribution of internal coordinates to the potential energy distributions. The obtained evidence suggests that methylation increases the overall structural flexibility of cytosine and that all molecules in this study populate a non-planar conformation 50% of the time.  相似文献   
998.
The serum concentration of two pro-angiogenic cytokines: basic fibroblast growth factor (bFGF) and transforming growth factor beta1 (TGF-beta1), and anti-angiogenic factor endostatin in the serum of 80 never treated B-cell chronic lymphocytic leukemia (CLL) patients and 27 healthy volunteers was measured using an enzyme linked immunosorbent assay. The serum levels of both bFGF and TGF-beta1 were found to be significantly higher in the CLL group (median 40.5 pg/ml and 38.6 ng/ml respectively) when compared to the control group (median 9.4 pg/ml and 18.9 ng/ml, respectively) (p<0.001). The levels of endostatin were not significantly different in CLL and control groups (median 12.3 ng/ml and 8.4 ng/ml, respectively) (p=0.09). In the group of CLL patients the level of bFGF was significantly higher in patients with progressive disease as compared with patients with stable disease (median 90.5 pg/ml and 40.5 pg/ml respectively) (p<0.001). Patients in Rai stage III and IV also had significantly higher levels of bFGF than patients in Rai stage 0-II (median 100.1 pg/ml and 29.3 pg/ml respectively) (p<0.001). The levels of both TGF-beta1 and endostatin were lower in patients in Rai stage III and IV (median 28.9 ng/ml and 9.1 ng/ml respectively) than in patients in Rai stage 0-II (42.8 ng/ml and 13.1 ng/ml respectively) (p<0.001 and p=0.002 respectively). The level of endostatin was also lower in the group of CLL patients with progressive disease (median 10.0 ng/ml) as compared to patients with stable disease (median 20.5 ng/ml) (p=0.008). In conclusion, the disturbance in the balance between pro- and anti-angiogenic factors may have an important influence on the course of CLL.  相似文献   
999.
A series of new (3,4) beta-methylenecepham and carbacepham analogues were synthesised as potential antibacterial agents. The key step of the synthesis included presumed generation of the carbene species from the oxalimide substrate effected by triethylphosphite and its intramolecular addition to the double bond. The stereochemistry of the tricyclic system has been elucidated by NMR and X-ray crystallography. In preliminary screening, two of the synthesised compounds exhibited modest antibacterial activity at 1.5-2.0 mg/mL against a number of bacterial strains.  相似文献   
1000.
Alu elements have inserted in the human genome throughout primate evolution. A small number of Alu insertions have occurred after the divergence of humans from nonhuman primates and therefore should not be present in nonhuman primate genomes. Most of these recently integrated Alu elements are contained with a series of discrete Alu subfamilies that are related to each other based upon diagnostic nucleotide substitutions. We have extracted members of the Alu Yd subfamily that are derivatives of the Alu Y subfamily that share a common 12-bp deletion that defines the Yd lineage from the draft sequence of the human genome. Analysis of the Yd Alu elements resulted in the recovery of two new Alu subfamilies, Yd3 and Yd6, which contain a total of 295 members (198 Yd3 and 97 Yd6). DNA sequence analysis of each of the Alu Yd subfamilies yielded age estimates of 8.02 and 1.20 million years old for the Alu Yd3 and Yd6 subfamilies, respectively. Two hundred Alu Yd3 and Yd6 loci were screened using polymerase chain reaction (PCR) assays to determine their phylogenetic origin and associated levels of human genomic diversity. The Alu Yd3 subfamily appears to have started amplifying relatively early in primate evolution and continued propagating albeit at a low level as many of its members are found in a variety of hominoid (humans, greater and lesser ape) genomes. Only two of the elements are polymorphic in the human genome and absent from the genomes of nonhuman primates. By contrast all of the members of the Alu Yd6 subfamily are restricted to the human genome, with 12% of the elements representing insertion polymorphisms in human populations. A single Alu Yd6 locus contained an independent parallel forward insertion of a paralogous Alu Sq sequence in the owl monkey. These Alu subfamilies are a source of genomic fossil relics for the study of primate phylogenetics and human population genetics.  相似文献   
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