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91.
92.
Genetic recombination can generate altered restriction specificity.   总被引:22,自引:2,他引:22       下载免费PDF全文
A recombinant strain, isolated following the transduction of an Escherichia coli recipient carrying the Salmonella typhimurium (SB) specificity genes with DNA from a donor having the Salmonella potsdam (SP) specificity, was shown [Bullas, L.R., Colson, C. & Van Pel, A. (1976) J. Gen. Microbiol. 95, 166-172] to have neither SB nor SP specificity but to encode a novel restriction specificity, SQ. The heteroduplex analysis of the hsdS (specificity) genes of the SB and SP restriction and modification systems described here identifies a conserved sequence of around 100 base pairs flanked by two nonhomologous regions each of approximately 500 base pairs. This organization parallels that previously deduced from the DNA sequences of the hsdS genes of the related E. coli K-12, B, and D restriction systems. The present heteroduplex analyses further show that the hsdS gene conferring the SQ specificity derives one nonhomologous region from the SB gene and the other from the SP gene, as predicted from genetic exchange within the conserved sequence. This finding supports the idea that two domains of an hsdS polypeptide, which are different for each specificity, may correlate with two regions of the DNA sequence recognized. It has been shown that the recognition sequences for E. coli K-12 and B each consist of two short oligonucleotide sequences interrupted by a nonspecific sequence. A similar organization is suggested for the Salmonella specificity systems, providing the potential for evolutionary diversification of restriction specificities as a result of recombination within the conserved sequence of the hsdS gene.  相似文献   
93.
BACKGROUND: In advanced vaginal recurrences of cervical and endometrial carcinomas therapeutic options are rare because of preceding therapy. PATIENTS AND METHODS: 23 patients developing advanced vaginal recurrences of cervical and endometrial carcinomas were included. 15 patients started with external-beam therapy to the pelvis and eight patients after preceding radiotherapy underwent brachytherapy alone. All patients had ultrasound-guided implantation of transvaginal or transperineal interstitial needles for brachytherapy. Median prescribed total dose was 64 Gy. RESULTS: 18 patients (78%) achieved complete remission. Six patients are alive without tumor and one with tumor after a median follow-up of 64 months. 14 patients died of tumor and two of intercurrent disease. 5-year disease-specific survival and local control rate were 43% and 47%, respectively, in patients with complete remission. Univariate analysis found time to relapse > 2 years, initial diameter < or = 4 cm, initial volume < 15 cm(3), no extension to the pelvic side wall, volume before brachytherapy < 7.5 cm(3), brachytherapy coverage index > 0.8, and prescribed total dose > 64 Gy being positive predictors for local control and survival. CONCLUSION: The use of ultrasound guidance for placement of interstitial needles in template-based brachytherapy of advanced recurrent gynecologic malignancies is a feasible, safe, and cheap method with encouraging results. Today, ultrasound imaging can be also used to some extent for treatment planning which requires further development. Patient- and treatment-related prognostic factors can be defined.  相似文献   
94.
Sandifer's syndrome is a rare, probably underdiagnosed, and usually pediatric movement disorder associated with gastroesophageal reflux disease. Often, it is misdiagnosed as epilepsy or paroxysmal dyskinesia. We report the case of an adult female with Sandifer's syndrome initially diagnosed as focal epilepsy and treated inefficiently with anticonvulsants for two years.  相似文献   
95.
This study evaluated the resource use of patients with epilepsy in the German district of Marburg-Biedenkopf. A cross-sectional cohort of consecutive adults with epilepsy, irrespective of seizure severity, duration of illness and epilepsy syndrome, was investigated in all health-care sectors. Costs of inpatient and outpatient treatment were derived from billing data of participating hospitals and office-based physicians. Data on socioeconomic status, course of epilepsy and further direct and indirect costs were recorded using patient questionnaires. We enrolled 366 patients from the district of Marburg-Biedenkopf and calculated annual epilepsy-specific costs of €7738 per patient. Direct costs contributed 31.1% (€2406) and indirect costs 68.9% (€5332) of the total costs. Direct medical costs were mainly due to hospitalization (33.2% of total direct costs) and anticonvulsants (26.7%). Costs of admissions were due to status epilepticus (24.4%), video-EEG monitoring (14.8%), newly diagnosed patients (14.4%) and seizure-related injuries (8.8%). Indirect costs were mainly due to early retirement (38.0%), unemployment (35.9%) and days off due to seizures (26.2%). The mean costs of epilepsy found in our study were lower than those found in studies conducted at European epilepsy centers due to the inclusion of patients in all health-care sectors.  相似文献   
96.
97.

Objective

Evaluating the information provision procedure about prenatal screening for Down syndrome, using informed decision-making as a quality-indicator.

Methods

Questionnaire- and register-based surveys. Midwives associated with 59 midwifery practices completed process data for 6435 pregnancies. Pregnant women (n = 510) completed questionnaires on informed decision-making.

Results

Midwives offered information to 98.5% of women; 62.6% of them wished to receive information, of these, 81.9% actually received information. Decision-relevant knowledge was adequate in 89.0% of responding women. Knowledge about Down syndrome was less adequate than knowledge about the screening program. Participants in the screening program had higher knowledge scores on Down syndrome and on the screening program than non-participants. Of the women who intended to participate (35.8%), 3.1% had inadequate knowledge. A total of 75.5% of women made an informed decision; 94.3% of women participating in the screening program, and 64.9% of women not participating.

Conclusion

This quality assurance study showed high levels of informed decision-making and a relatively low participation rate in the national screening program for Down syndrome in the Netherlands. Knowledge of the Down syndrome condition needs to be improved.

Practice implications

This evaluation may serve as a pilot study for quality monitoring studies at a national level.  相似文献   
98.
99.
Free zinc is considered to be the exchangeable and biological active form of zinc in serum, and is discussed to be a suitable biomarker for alterations in body zinc homeostasis and related diseases. Given that coronavirus disease 2019 (COVID-19) is characterized by a marked decrease in total serum zinc, and clinical data indicate that zinc status impacts the susceptibility and severity of the infection, we hypothesized that free zinc in serum might be altered in response to SARS-CoV-2 infection and may reflect disease severity. To test this hypothesis, free zinc concentrations in serum samples of survivors and nonsurvivors of COVID-19 were analyzed by fluorometric microassay. Similar to the reported total serum zinc deficit measured by total reflection X-ray fluorescence, free serum zinc in COVID-19 patients was considerably lower than that in control subjects, and surviving patients displayed significantly higher levels of free zinc than those of nonsurvivors (mean ± SD; 0.4 ± 0.2 nM vs. 0.2 ± 0.1 nM; p = 0.0004). In contrast to recovering total zinc concentrations (r = 0.706, p < 0.001) or the declining copper–zinc ratio (r = −0.646; p < 0.001), free zinc concentrations remained unaltered with time in COVID-19 nonsurvivors. Free serum zinc concentrations were particularly low in male as compared to female patients (mean ± SD; 0.4 ± 0.2 nM vs. 0.2 ± 0.1 nM; p = 0.0003). This is of particular interest, as the male sex is described as a risk factor for severe COVID-19. Overall, results indicate that depressed free serum zinc levels are associated with increased risk of death in COVID-19, suggesting that free zinc may serve as a novel prognostic marker for the severity and course of COVID-19.  相似文献   
100.
Patients infected with the human immunodeficiency virus (HIV) often develop multiple papillomatous lesions of the oral cavity. In the present study, a total of 67 biopsies from benign oral lesions were analyzed for the presence of human papillomavirus (HPV) DNA using Southern-blot hybridization in combination with a polymerase chain reaction designed to detect all known HPV types, as well as unidentified types. These samples, collected at random from a high-risk population, were subsequently divided into 57 biopsies originating from patients with confirmed HIV infection and 10 biopsies from patients with unknown HIV status. Each sample was amplified with 7 different combinations of degenerate primers. All amplified products were sequenced. HPV DNA sequences were detected in 67% (45/67) of the samples. HPV 7 (19%) and HPV 32 (28%) were the predominant HPV types. HPV 32 was present in 2/4 fibromas tested. Two new HPV types, HPV 72 and HPV 73, were identified in oral warts with atypia. The complete genomes of these viruses were cloned and sequenced. Other HPV types detected were HPV 2a, HPV 6b, HPV 13, HPV 16, HPV 18, HPV 55, HPV 59 and HPV 69. © 1996 Wiley-Liss, Inc.  相似文献   
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