首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The purpose of this study was to determine whether the addition of small quantities of minor lecithin components (phosphatidylinositol, phosphatidic acid, lysophosphatidylethanolamine, and cholesterol) and Pluronic F68 to lecithin could improve the stability of lecithin-stabilized perfluorocarbon emulsions. Attempts were made to correlate emulsion stability with interfacial properties (tension and charge). Dynamic interfacial tension was determined using a Teflon Wilhelmy plate method [reported previously (1)]. Emulsions were prepared by microfluidization. Microelectrophoresis was used to measure emulsion droplet charge, and photon correlation spectroscopy and Coulter analysis were used to determine emulsion stability as a function of droplet size. Thermal kinetic accelerated stability testing was conducted. Various droplet size parameters were used to compare emulsion stabilities, and an overall stability ranking, based on these parameters, was obtained for each emulsion. Small quantities of additives altered emulsion stability and these data were correlated with interfacial properties and initial droplet diameters. The addition of cholesterol to lecithin resulted in the most stable perfluorocarbon emulsion.  相似文献   

2.
Germ theory and pure culture methods have provided invaluable information concerning the role of bacteria in diseases resulting from a single organism which bypasses a host's defenses. However, they do not provide sufficient information concerning the synergisms which allow the members of biofilm communities to proliferate more effectively as communities rather than as individuals. The mechanisms of these synergies are potential targets for antimicrobial agents as well as potential mechanisms of resistance to antimicrobial agents. Understanding community-level phenomena in oral biology requires the culture, identification, and classification of functional plaque communities as well as new methods of identifying and quantifying communal relationships. Cultured biofilm communities also provide ideal models of bacterial self-organization in which information related to adaptive strategies arises not only through the recombination of genes within genomes, but also through the recombination of organisms within communities.  相似文献   

3.
We studied 217 vulvar HPV infection patients by clinically, pathologically, and virologically. From 90.6% of the cauliflower-like vulvar lesions and 29.7% of the papillomatous and finger-like lesions, we detected HPV 6/11 DNA by dot blotting hybridization. The patients in 90.0% of the cauliflower-like group and 9.8% of the papillomatous and finger-like group had a high risk factor to intercourse with different sex partners (P < 0.0001). The pathological characteristics, nature history, and response to treatment were different. According to clinical, pathological, and virological findings divided three types: vulvar HPV infection type 1 (or condylomata acuminata), vulvar HPV infection type 2, and vulvar HPV infection type 3.  相似文献   

4.
Teleost retinas adapted to light show numerous spinules invaginated in the cone pedicles whereas darkness induces a reduction in the number of spinules. Horizontal cells show nematosomes whose size decreases as the number of spinules increases. We have investigated the involvement of actin filaments in spinule formation, by using cytochalasin D through intraocular injection into an eye. The ultrastructural analysis reveals that cytochalasin D impairs spinule formation and nematosome-size reduction in both treated and contralateral untreated retinas.  相似文献   

5.
Two hundred and sixteen cases of human papillomavirus infection of the vulva from 1984 to 1991 in the Affiliated Hospital of Qingdao Medical College were reviewed, and were immunohistochemically studied by ABC method to detect HPV-Ag. The results showed that the demonstration of diagnostic koilocytes is very important in diagnosis of HPV infection in routine tissue slides examination. But in cases of atypical morphological changes; when diagnostic koilocytes were not formed in early stage, the demonstration of brown color granules in the nuclei of prickle cells is very diagnostic for positive HPV infection. In occasional cases, the diagnostic koilocytes do not demonstrate brown color granules in their nuclei. The explanation is that HPV-Ag was exhausted during metabolism. Besides, the cell membrane of basal cells are stained with brown color granules, while the morphological changes of upper layers of squamous epithelium have not appeared yet, therefore, there were no HPV-Ag positive reactive cells. It is probably showed that the HPV-Ag is primarily formed and appeared in the cell membrane of basal cells.  相似文献   

6.
7.
OBJECTIVE: To identify risk factors for the detection of prevalent and incident anal human papillomavirus (HPV) infection, and HPV persistence among HIV-seropositive and seronegative homosexual men. DESIGN: Longitudinal study of 287 HIV-seronegative and 322 HIV-seropositive men attending a community-based clinic. METHODS: Subjects underwent an interview and examination; specimens were collected for HIV serology and assessment of anal HPV and HIV DNA. RESULTS: Anal HPV DNA was detected at study entry in 91.6% of HIV-infected men, and 65.9% of men not infected with HIV. HPV detection was associated with lifetime number of sexual partners and recent receptive anal intercourse (HIV-seronegative men), decreased CD4+ lymphocyte count (HIV-seropositive men), and anal warts (all men). Among men negative for HPV at study entry, subsequent detection of HPV was associated with HIV, unprotected receptive anal intercourse, and any sexual contact since the last visit. Among men positive for HPV at study entry, subsequent detection of additional HPV types was more common among HIV-seropositive men. Becoming HPV negative during follow-up was less common among men with HIV or high HPV levels at study entry. Among those with HIV, HPV persistence was associated with presence of anal HIV DNA, but not with CD4+ lymphocyte count. CONCLUSIONS: Risk of anal HPV infection appears to increase with sexual exposure, epithelial trauma, HIV infection and immune deficiency. Incident infection may result from recent sexual exposure or reactivation of latent infection. Further studies are needed to elucidate the mechanism by which HIV DNA in the anal canal increases the risk of HPV persistence.  相似文献   

8.
Nematodes are known to be a useful system for studies of comparative development. Here we perform a molecular phylogenetic analysis to allow for the independent interpretation of the developmental and morphological changes observed among a selected set of nematode species. Our molecular phylogenetic analysis is based on coding regions of the genes for RNA polymerase II, the small subunit rRNA and an expansion segment of the large subunit rRNA. Sequences were compared from five species in the family (Rhabditidae) that includes the developmental model organism Caenorhabditis elegans and from an outgroup taxon Aduncospiculum halicti (Diplogasterina). The phylogenetic analysis does not support the monophyly of the subfamily Mesorhabditinae and identifies the unnamed strain PS1010 as a sister taxon of C. elegans despite its morphologically divergent buccal capsule. On the basis of the inferred framework, we can begin to interpret the evolution of vulval development and of morphological differences among these nematode species.  相似文献   

9.
We conducted a prospective study to investigate whether human papillomavirus (HPV) could be vertically transmitted to neonates. Pregnant women (N = 203) were tested for HPV DNA infection during the third trimester and again during labor prior to delivery. Their newborns (N = 203) were tested 1 to 3 days after delivery. Among the mothers, 12.3% (N = 25/203) typed HPV positive at either or both maternal specimen collection periods, whereas only 1.0% of the neonates (N = 2/203) typed positive. This low transmission rate may be due in part to the fact that 65% of mothers who were HPV positive during the third trimester tested HPV negative by labor/delivery. The higher frequency of risks associated with maternal HPV infection were similar to those found in studies of cervical dysplasia and cancer: younger age at first intercourse and first pregnancy, number of sexual partners, and longer duration in use of oral contraceptives. In addition, those who were past smokers and had a shorter recency and latency period in smoking were more likely to be detected with HPV.  相似文献   

10.
11.
The effect of sexual behavior on the risk for cervical dysplasia was evaluated in a case-control study. Cases (n = 257) had a histologically confirmed diagnosis of cervical dysplasia. Controls (n = 705) were sampled from the general population. A postal questionnaire was used to obtain information about, among other things, age at first sexual intercourse, number of sexual partners, current frequency of intercourse and contraceptive use. Information was also collected about other risk factors for cervical dysplasia, in order to adjust for possible confounding. We observed higher risks for cervical dysplasia (mild, moderate and severe) with increasing number of sexual partners. This effect appeared to be dependent on smoking behaviour. For women who reported more than six sexual partners, the adjusted odds ratio (aOR) was 9.1 (95% CI: 3.5-23.7) for non-smokers, and 26.4 (95% CI: 11.8-58.8) for women who smoked > or = 20 cigarettes per day. The effects of age at first sexual intercourse and current frequency of intercourse disappeared after adjustment for other risk factors. Use of oral contraceptives for > 10 years increased the risk (aOR = 2.3; 95% CI: 1.2-4.6). Thus, the number of sexual partners, especially in combination with smoking behaviour, appeared to be the most important risk factor for cervical dysplasia.  相似文献   

12.
The DNA in situ hybridization (DISH) and conventional solution phase polymerase chain reaction (PCR) were applied to identify human papillomavirus (HPV) DNA in cervical specimens of Turkish women. Samples consisted of 21 cervical brushings from pregnant women and 20 paraffin-embedded biopsies from women with condylomatous or dysplasic lesions. It was found that two out of 21 (9.5%) pregnant women were harbouring HPV-DNA detected by PCR. One woman was infected with HPV 16/30's and the other with an unidentified type. As for the biopsy specimens, the rate of HPV-DNA positivity was 30% and 45% by DISH and PCR, respectively. A double infection was observed in more than 50% of the positive cases. Moreover, HPV 18 was never detected. The results indicated that HPV-DNA is rarely present in cytomorphologically normal smears from pregnant women. The PCR method was successfully adapted for HPV typing in clinical lesions which simultaneously contained different HPV sequences.  相似文献   

13.
HPVs are small DNA tumor viruses with an icosahedral virion structure. All members of the genus cause diverse benign lesions, and some members promote the development of carcinoma. The viruses do not replicate in culture without extraordinary measures, and virtually all studies to date have used molecular methods to elucidate their biology and natural history. Tests of choice for detecting HPV from clinical specimens are based on nucleic acid probe technology. Until recently, most epidemiologic and molecular studies employed Southern blot (SB), dot blot (DB), and in situ hybridization (ISH). With the exception of ISH, which continues to have many uses and a strong following in the pathology community, SB and DB have been essentially replaced by polymerase chain reaction (PCR) and the Hybrid Capture System (HCS). These newer in vitro probe tests have proven to be accurate and robust workhorses for epidemiologic and clinical use. Automation promises to revolutionize HPV testing in the near future and will allow cost-effective mass screening worldwide.  相似文献   

14.
The role of the males who are sexual partners of females with genital human papillomavirus (HPV) infection and premalignant lesions is explored in the present study. Within a period of 3 years, 391 females with genital premalignant and HPV-associated lesions were examined and treated at the Cervical Pathology Unit of the Tel Aviv Medical Center. The male partners of all the women were asked to attend this unit, and 322 of them responded. All participants underwent colposcopic examination of the anogenital area followed by colposcopically guided biopsies from the most representative lesions, when present, part of which included in situ hybridization (ISH) of HPV DNA sequences 6/11 and 16/18. The histological prevalence of HPV among the male partners was 86.6% (185 of 213 biopsies). Of the 48 couples who had ISH evaluations, the ISH could not identify any copy of HPV DNA in 58.3% of the males (28 cases) and 41.6% of the females (20 cases). Among the males, HPV 6/11 and 16/18 were found in 17 (35.4%) and 3 cases (6.2%), respectively, and among the females there were 23 (48.0%) and 5 cases (10.4%), respectively. Correlation of HPV DNA sequences 6/11 and 16/18 between the couples was found in six (12.5%) and in one (2.0%), respectively. These data do not support a direct contamination by the current male partner. The question of treating the male partner of a woman with genital HPV and premalignant lesions remains to be evaluated.  相似文献   

15.
Occurrence of the antibodies against human papillomavirus (HPV) 16 proteins E4 and E7 is specifically but independently associated with cervical cancer. To correlate HPV DNA and antibody data, we examined the biopsy specimens and sera, by polymerase chain reaction (PCR) and by ELISA, respectively, from 51 patients with cervical cancer (including 3 recurrent cases) and 22 with cervical intra-epithelial neoplasia. Consensus primers for the L1 region were used for PCR and bacterially expressed, purified fusion protein HPV-16 E4 and non-fusion protein HPV-16 E7 were used for ELISA. HPV-16 DNA and other HPV types were detected in 17 and 25, respectively, out of 51 cases of cervical cancer. Ten out of the 17 HPV-16-DNA-positives were positive either for anti-E4 or for anti-E7: positivities for anti-E4, for anti-E7, and for both were 6/17, 5/17 and 1/17 respectively. Three anti-E7-positives consisted of those for HPV-33, -52 and -58 DNA, suggesting that limited cross-reaction occurred between the HPV types. Among the HPV-16-DNA-positive cases of cancer, lymph-node or distant metastasis was recorded more frequently in the seropositives than in the seronegatives. Our results show that the HPV-16 anti-E4 or anti-E7 occurs in some, but not in all, of the HPV-16-DNA-positive cases, and support the hypothesis that the presence of the HPV-16 antibodies can be used as a marker for possible metastasis.  相似文献   

16.
In 2 x 3 factorial experiments, 240 broiler chicks were fed diets containing 0, 0.01, and 0.02% beta-carotene or canthaxanthin with or without 5 ppm aflatoxin to determine the effects of these two carotenoids on the health and well-being of broilers subjected to aflatoxin poisoning. Neither beta-carotene nor canthaxanthin was effective at overcoming the growth-depressing effects of aflatoxin. Relative liver weights were significantly higher in broilers receiving dietary aflatoxin in the presence of beta-carotene but not canthaxanthin. beta-Carotene and canthaxanthin had no effect on antibody production against infectious bursal disease (IBD). Interestingly, secondary antibody production against IBD was enhanced by the presence of aflatoxin in the diet. Canthaxanthin significantly increased the concentrations of cholesterol, total protein, uric acid, and triglyceride, all of which were significantly depressed by aflatoxin. beta-Carotene did not effect any of the measured blood analytes. There was a significant interaction between canthaxanthin and aflatoxin with respect to creatine kinase activity. Creatine kinase activity decreased as dietary canthaxanthin increased in the presence of aflatoxin. The data suggest that beta-carotene is not effective at ameliorating aflatoxicosis in broiler chickens but that canthaxanthin may be somewhat effective with respect to certain clinical blood chemistry indicators.  相似文献   

17.
Smooth muscle cell (SMC) proliferation is inhibited both in vivo and in vitro by heparin. However, the precise mechanisms of action are still not understood. The analogy between two sulfated polysaccharides, heparin and fucan, has led us to compare in detail their effects on SMC growth. We have prepared and characterized a 19 kDa fucan fraction from brown seaweed, Ascophyllum nodosum. Fucan affects the growth of SMCs in a time- and dose-dependent, reversible and non-toxic fashion. As determined by cell counting, [3H]thymidine incorporation, and microcytofluorimetry analysis, heparin was less active than fucan in inhibiting SMC growth. Fucan and heparin act by preferential blocking of G0/G1, thus decreasing the G0/S transition. Binding experiments with [125I]fucan indicated saturable, unlabeled-fucan displaceable binding sites with an apparent Kd of 30 nM. Moreover, displacement experiments performed with various polysaccharides revealed that antiproliferative compounds interacted with these membrane sites, but non-antiproliferative polysaccharides (dextran, chondroitin sulfate) did not, providing evidence of a correlation between binding to SMCs and their antiproliferative activity. When cells were exposed at 37 degrees C to a fluorescent 5-([4,6-dichlorotriazin-2-yl]-amino)fluorescein (DTAF)-fucan, internalization occurred and punctate vesicles were observed which accumulated rapidly in the perinuclear region as previously reported for heparin. Nuclear preparations (membranes + contents) of cultured SMCs previously incubated with radiolabeled heparin or fucan indicated the presence of radioactivity, suggesting an antiproliferative action of both polysaccharides at the nuclear level. Collectively, these observations indicated that fucan and heparin share some similar mechanisms of action, such as SMC growth inhibition, binding, and internalization. In the accompanying paper (Logeart et al., Eur. J. Cell Biol. 74, 1997, this issue), we describe the effect of fucans of different molecular weights and conclude that there is no direct link between polysaccharide degradation and the antiproliferative effect on SMCs.  相似文献   

18.
OBJECTIVE: To study a possible etiologic relationship between the prognosis of uterine cervical dysplasia, association of type-specific human papillomavirus (HPV) DNA and cytologic features characteristic of HPV infection. STUDY DESIGN: Two hundred thirteen cases of uterine cervical dysplasia were selected in which follow-up survey for more than two years was possible. Frequency of the presence of HPV DNA in the DNA samples was determined by polymerase chain reaction. The cervical scrapings were also examined microscopically for the frequencies of cells with cytologic features characteristic of HPV infection. RESULTS: HPV was positive in 98 cases (46.0%). The high-risk type of HPV was detected at almost the same frequencies in both progressive and regressive states of dysplasia. Cytologic features were more evident in cells infected with the low-risk type of HPV. CONCLUSION: Involvement of an as-yet-unknown factor or factors coupled with infection with the high-risk type of HPV is implicated in the progression of uterine cervical dysplasia. Cytologic features characteristic of HPV infection may serve as a diagnostic marker for a favorable prognosis in dysplasia.  相似文献   

19.
Out of 235 patients discharged from the Department of Thoracic Surgery, Silesian Medical Academy, after treatment of primary spontaneous pneumothorax between 1981 and 1993, 232 (98.7%) answered our questionnaire and so were included in the study. Mean follow-up time was 10.4 years. No recurrence of the disease was reported by any of 79 patients who had been treated by surgical procedure/thoracotomy plus pleurectomy/, but 21 (14.3%) out of 147 treated by paracentesis reported a recurrence of pneumothorax. In 17 patients the recurrence was the first-time case, in 3 the second-time, in 1 the third-time. Out of 232 patients, 10 (4.3%) had a recurrence of pneumothorax on the opposite side. Achieving expansion of the lung, 80% of the patients reported no problems at all. Only 6 (2.6%) of the whole group stated they could no longer work in their profession because of the pneumothorax they had suffered in the past.  相似文献   

20.
BACKGROUND: Identifying predictors of treatment outcome can suggest ways to improve treatment delivery and understanding of its mechanism of action. METHOD: Predictors of treatment outcome were sought among 46 out-patients with obsessive-compulsive disorder who completed a nine-week randomised controlled trial of two forms of exposure therapy with ritual prevention. RESULTS: In both exposure conditions the best predictor of good outcome at the end of treatment (week 9) and of follow-up (week 32) was early compliance in doing exposure homework within a week of starting treatment. A weaker predictor of good outcome at follow-up was within-session reduction in anxiety from weeks 0 to 4. CONCLUSION: The strongest and most consistent predictor of better outcome to weeks 9 and 32 was compliance with exposure and ritual prevention in the first week of treatment.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号