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71.
Objective: To retrospectively review the management of adenocarcinomain situof the uterine cervix, to determine the outcome of conization versus hysterectomy, and to compare the results achieved by different methods of conization. Methods: We performed a retrospective pathology and chart review of 46 patients with cervical adenocarcinomain situfrom January 1980 to October 1994. Results: Nine patients were managed during the first half of the study period and 37 were managed in the second half. The mean age of patients was 38.4 years (range 25–72). Forty-five of 46 patients were diagnosed as a result of an abnormal Pap smear, although only 19 smears indicated adenocarcinomain situor other glandular abnormalities. Cold knife conization resulted in a 33% rate of positive margins for adenocarcinomain situcompared to 50% for large loop excision of the transformation zone (LLETZ). Among 24 conservatively managed patients with negative conization margins, there have been 2 (8.3%) recurrences of adenocarcinomain situ.Among patients not undergoing hysterectomy as definitive treatment, 1 of 18 (6%) patients undergoing cold knife conization recurred, compared to 4 of 14 (29%) managed with LLETZ, despite a 63.4-month shorter mean follow-up interval for the LLETZ patients. Conclusions: Cold knife conization is associated with a lower rate of recurrence of cervical adenocarcinomain situcompared to LLETZ. We recommend cold knife conization for patients who are not treated with hysterectomy.  相似文献   
72.
Enzymatic synthesis of penicillins   总被引:5,自引:0,他引:5  
Different penicillins (phenylacetyl, 2-hydroxyphenylacetyl, 4-hydroxyphenylacetyl, phenoxyacetyl and 2-thiopheneacetylpenicillin) have been synthesized "in vitro" by direct N-acylation of 6-aminopenicillanic acid (6-APA) with the acyl group of several acyl-CoA derivatives. The enzyme that catalyzes these reactions, acyl-CoA: 6-APA acyltransferase of Penicillium chrysogenum, was purified to homogeneity (374-fold) and its amino acid composition is given. This protein accepts as substrates several aliphatic acids and different aromatic acids with the only requirement that an acetyl-CoA moiety must be present in the substrate molecule. Shortening or lengthening of the acyl moiety prevents the 6-APA-N-acylation reaction. The presence of an amino group in the alpha-position of the acetyl group does not allow this molecule to be used as substrate. However, different substitutions in the phenyl group (hydroxylation of the carbons 2 and 4) or its replacement by another aromatic ring (thiophene) were accepted with varying reactions rates in the acylation reaction when a 176-fold purified acyltransferase was employed. The homogeneity pure enzyme accepts as substrate thiophene acetyl-CoA but it did not 2-hydroxyphenyl and 4-hydroxyphenylacetyl-CoA. The presence of an oxygen atom between the aromatic and the acetyl moieties did not affect the catalysis.  相似文献   
73.
DNA isolated from chondrosarcoma cells effectively transformedNIH-3T3 cells and human foreskin fibroblasts. The transfectedNIH-3T3 cells, directly implanted three or four passages later,formed progressively growing tumors ( 2.0 cm in diameter) subcutaneouslyin nude mice. No metastasis was evident upon pathological examinationof the tumor bearing mice. Transfected human foreskin fibroblaststhat exhibited anchorage independent growth formed only smalltumors in nude mice (<0.6 cm in diameter). The transfectedhuman cells which exhibited anchorage independent growth reactedwith the monoclonal antibody 345.134S, specific for an epitopeexpressed by human sarcoma cells. The transfected NIH-3T3 cellsdid not exhibit reactivity with the same monoclonal antibody.Southern blot analysis of the DNA prepared from the transfectedNIH-3T3 cells, that developed as a progressively growing tumorin a nude mouse, revealed the presence of human repetitive DNAsequences.  相似文献   
74.
Wild rodents and the subadult Ixodes ricinus (L.) ticks infesting them were examined for the presence of Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner s.l. in a sylvatic habitat in west central Poland during May-September 2002. In total, 818 feeding ticks were recovered from 73 infested yellow-necked mice, Apodemus flavicollis Melchior; in addition, bank voles, Clethrionomys glareolus Schreber, were rarely captured and proved to be weakly parasitized. Only 2.7% of A. flavicollis and 2.2% of 320 engorging larvae were polymerase chain reaction (PCR) positive for the bacterium. All spirochete-PCR-positive samples yielded exclusively B. burgdorferi s.s. This genospecies was also the most prevalent in questing nymphs and accounted for 87.5% of the total number of Borrelia infections in nymphal ticks collected during May and June 2 yr later. The presence of the same genospecies both in naturally engorged larvae and blood-positive animals as well as the high predominance of B. burgdorferi s.s. in questing nymphs strongly differs from most study sites investigated in Europe. This unique pattern of Borrelia-diversity in both rodents and ticks seems to be determined by highly site-specific host vertebrate cenosis, and yellow-necked mice are involved in the maintenance of B. burgdorferi s.s. in the forest habitat. However, the transmission efficiency of this spirochete from the mice to the I. ricinus vector seems to be very low. The research provides additional information on the complexity of B. burgdorferi s.l. ecology in Europe, pointing to the importance of the local host community.  相似文献   
75.
The cytokines that predominate at the healthy maternal fetal interface are compatible with those produced by Th2/3 cells. Th1 and Th2 type immunity are mutually inhibitory and cytokine profiles are regulated in part by maternal sex steroids. The immune and endocrine equilibrium required for pregnancy success may be modified by external factors including stress, infection and altered maternal nutrition. The latter has received surprisingly little attention particularly as the effects of nutrition on immunity per se are widely documented. We have used animal models to investigate the effects of altered maternal diet on both immune and endocrine mechanisms important for pregnancy success. In rodents, maternal deficiencies in iron and vitamin A have been shown to negatively alter the expression of placental cytokines and in the case of vitamin A, increase placental apoptosis. In a highly controlled sheep model, overfeeding young growing females carrying singleton pregnancies restricts placental growth resulting in the premature delivery of low birth weight lambs. This is associated with reduced maternal concentrations of progesterone, placental lactogen, PSPB, GH and increased insulin, IGF-1, leptin and thyroid hormones (Wallace et al. Reprod 2001; 122:347–357). At day 80 of gestation (term=145) the placentae of overfed dams exhibit reduced expression of proliferation markers, predominantly in the fetal trophectoderm, and increased expression of the pro-apoptotic protein bax. These data indicate an altered balance between placental proliferation and apoptosis, possibly linked to maternal endocrine status. We conclude that maternal diet has considerable impact on immuno-endocrine mechanisms critical for pregnancy success.  相似文献   
76.
This study aims at assessing the accuracy of estimates of body composition provided by bioimpedance (BIA) equations developed for U.S. populations when applied to a sample of Guatemalan farmers. If these equations were shown to have low validity, the second objective was to develop more accurate estimates of fat-free mass (FFM). One hundred males and females 19 to 45 years of age were randomly selected from four rural communities in the Western Highlands of Guatemala. Bioimpedance equations explained 59 and 33% of the variation in FFM, with a RMSE of 2.7 and 2.8 kg in males and females, respectively. Body fat (BF) predictions had a lower R2. Using the “all possible regressions” procedure, the best subset for prediction of FFM used anthropometric and BIA variables as predictors. The best model for men and women included only anthropometric variables: 75% of the variance in FFM for men and 70% of the variance in women was explained by this model. The RMSE was 2.1 and 1.9 kg for both groups, respectively. It is concluded that FFM can be estimated from anthropometric dimensions with a high degree of accuracy and use of BIA does not provide more valid estimates.  相似文献   
77.
Using a system that allows transfection of resting peripheral blood lymphocytes (PBLs) two questions were addressed: the kinetics of HIV replication from the state of proviral latency, and the impact of different parameters on the efficacy of protease inhibitors to control HIV replication. PBLs were transfected with an infectious full length HIV-DNA harboring a luciferase reporter gene and activated thereafter. Ritonavir was added at different times at doses ranging from to 0.06 to 1 microM. Viral expression was assessed by quantifying luciferase activity in cell extracts and levels of p24 HIV antigen in culture supernatants. After transfection and cell activation, intracellular expression of HIV proteins, as assessed by luciferase detection, occurred within 2 hr. HIV-gag p24 antigen was detected in culture supernatants between 6 and 8 hr post-activation. Ritonavir was effective in blocking viral replication when given within 4 hr following HIV reactivation, but a delay in ritonavir administration or breaches in ritonavir levels after 6 hr from transfection resulted in viral escape. HIV reactivation from proviral latency in PBLs is an extremely rapid process, faster than estimated from previous models. These data stress the need for maintaining effective antiretroviral concentrations to block completely viral replication.  相似文献   
78.
Supernumerary humeral heads of the biceps brachii muscle were found in 27 (15.4%) of 175 cadavers. They were bilateral in five cadavers and unilateral in 22 (8 left, 14 right), giving a total of 32 examples in 350 arms (9.1%). Depending on their origin and location, the supernumerary heads were classified as superior, infero-medial, and infero-lateral humeral heads. Previous studies were reviewed using this classification. The infero-medial humeral head was observed in 31 of 350 (9%) arms and was therefore the most common variation. The superior humeral head was observed in five (1.5%). The infero-lateral humeral head was the least common variation, observed only in one (0.3%) of 350 arms. A biceps brachii with three heads was observed in 27 of 350 (7.7%) arms and with four heads in five (1.4%) arms.  相似文献   
79.
The role of Serratia marcescens porins in antibiotic resistance   总被引:1,自引:0,他引:1  
The outer membrane permeability of Serratia marcescens was studied by comparing porin-deficient mutants with their parental strains. Omp1-deficient strains were selected by moxalactam resistance, whereas mutants lacking the Omp2 porin were obtained by experimental infection with the SMP2 phage, whose primary receptor is the Omp2 porin. The role of porins was demonstrated in quinolone accumulation assays, where semiquantitative differences in accumulation were observed. Permeability coefficients to cephaloridine of Omp1 mutants were determined and compared with those of the parental strain. The clinical isolates S. marcescens HCPR1 and 866 showed 30- to 200-fold reduced permeability coefficients when Omp1 porin was absent.  相似文献   
80.
2,4,5-trimethylthiazoline (TMT) is a volatile component of the anal gland secretion of the red fox and elicits behavioral and physiological fear responses in the rat. Using instrumental conditioning paradigms, we determined olfactory detection thresholds for TMT in three rats, a natural prey species of the red fox, and compared their performance to that of three squirrel monkeys, three spider monkeys and four pigtail macaques, all non-prey species of the red fox. We found that the rats were able to discriminate concentrations between 0.04 and 0.10 ppt (parts per trillion) of TMT from the odorless solvent which is by far the lowest olfactory detection threshold for an odorant reported in rats so far. In contrast, the spider monkeys needed 0.14-1.38 ppb (parts per billion), the pigtail macaques 0.41-4.07 ppb, and the squirrel monkeys 4.07-13.80 ppb to detect TMT which does not rank among the lowest olfactory thresholds reported for these three primate species. Thus, these results support the assumption that the behavioral relevance of an odorant may be an important determinant of a species' olfactory sensitivity.  相似文献   
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