Search PubMed⌕ Search

Biomedical subjects

A Arslan

Publications and source records attributed to A Arslan.

At least 73 records · Page 4Linked to original sources
PubMed1995

Characterization and co-culture of novel nontransformed cell lines derived from rat endometrial epithelium and stroma.

Normal and neoplastic growth of epithelial cells depends on mutual interactions between epithelial and stromal cells. As a tool for the study of the underlying molecular mechanisms, we have developed temperature-sensitive, nontransformed cell lines derived from rat uterine epithelium and stroma by transfecting primary cultures with a temperature-sensitive mutant of the SV40 large T antigen. The epithelial and stromal cell lines obtained shared relevant morphological characteristics with the primary cells from which they were derived. Immunocytochemical analysis showed that the epithelial cell lines expressed the intermediate filament cytokeratin, whereas the stromal lines expressed the intermediate filament vimentin. Alkaline phosphatase activity was present in all cell lines examined. All cell lines were anchorage dependent and did not form foci. One epithelial cell line expressed oxytocin mRNA, a gene product recently shown to be highly expressed in vivo in the uterine epithelium at term. If grown on Matrigel, this cell line formed domelike structures, a further characteristic of its differentiated phenotype. In an attempt to reconstitute an endometrium in vitro, epithelial cells were seeded on top of a layer of stromal cells. Paraffin cross sections showed that this in vitro system consisted of a bilayer structure. Four to five cuboidal epithelial cells were typically anchored atop one stromal cell, forming an endometriumlike tissue. The present in vitro system should provide a useful model for further studies on endometrial functions and epithelial/stromal cell interactions at a molecular level.

Alkaline Phosphatase↗
PubMed1995

Development of immortalized endometrial epithelial and stromal cell lines from the mink (Mustela vison) uterus and their effects on the survival in vitro of mink blastocysts in obligate diapause.

Mink endometrial cell lines were established by stable transfection of a plasmid vector encoding the SV40 large T antigen driven by the human beta-actin promoter. A second plasmid vector, pSV2neo, was employed for selection of transfected cells. Specificity and homogeneity of consequent cell lines were evaluated by immunocytochemistry employing antibodies against cytokeratin, desmin, and vimentin. Cytokeratin was found exclusively in epithelial cells, whereas vimentin appeared primarily in stromal cells. Neither cell line showed detectable desmin activity. These cell lines along with Buffalo rat liver (BRL) cells were employed in coculture with mink embryos in obligate diapause. Mink stromal and BRL cell lines were most effective in enhancing embryo survival in vitro. The percentages of cocultured embryos that survived for 72 h or more were 65% with epithelial cells, 75% with stromal cells, 68% with the combination of stromal and epithelial cells, and 93% with BRL cells. Only 23% of the embryos cultured without cells survived beyond 48 h. Embryo growth was also observed; some embryos in coculture showed trophoblastic outgrowth and adhesion to the cell surfaces. These results demonstrate that mink embryos in obligate delay can survive and develop in culture and that coculture with uterine or BRL cells increases the length and frequency of survival.

Alkaline Phosphatase↗
PubMed1995

Oxytocin receptor gene expression in the rat uterus during pregnancy and the estrous cycle and in response to gonadal steroid treatment.

It is well established that uterine oxytocin receptors (OTRs) are strongly up-regulated immediately before parturition as well as in response to estrogen (E2) administration. Progesterone (P4), on the other hand, induces a rapid down-regulation. We recently cloned the rat OTR gene and characterized its expression in the rat uterus. In this study, we examined the regulation of OTR messenger RNA (mRNA) levels in rat uterus during pregnancy, the estrous cycle, and in response to gonadal steroid treatment. OTR mRNA levels increased more than 25-fold during gestation: 4.5-fold during the first 21 days and 6-fold within 24 h between day 21 and the onset of parturition. Uterine OTR mRNA levels fell rapidly by 85% within 24 h following parturition. By in situ hybridization, OTR mRNA was localized specifically to the longitudinal and circular layers of the myometrium but was not detected in the endometrium. During the estrous cycle, OTR mRNA levels increased 2-fold between metestrus and proestrus, whereas oxytocin (OT) binding rose more than 10-fold within this same interval. Treatment of ovariectomized rats with E2 lead to a significant increase in both OTR mRNA levels (4.4-fold) and OT binding (< 6-fold). Cotreatment with P4 strongly reduced OT binding by 75% (P < 0.01) but did not significantly affect the E2-induced rise in OTR mRNA (11% decrease, P > 0.1). Our data suggest that the increased expression of OT binding sites observed at the onset of labor and at proestrus is mediated, at least in part, by an E2-induced up-regulation of OTR gene expression. However, it also appears that OTR mRNA levels are not the sole determinants of uterine OT binding. Specifically, P4-mediated OTR down-regulation cannot be explained by an effect on OTR mRNA accumulation and may involve novel mechanisms acting at translational or posttranslational levels.

Animals↗
PubMed1995

Gonadal steroid regulation of oxytocin and oxytocin receptor gene expression.

By Northern blot analysis and in situ hybridization, we have determined that, at term, the rat uterine epithelium represents a major site of oxytocin (OT) gene expression. OT mRNA levels increase > 150-fold during pregnancy and, at term, exceed hypothalamic OT mRNA by a factor of 70. By cryoultramicroscopy, OT immunoreactivity was localized to transport vesicles in the apical compartment of uterine epithelial cells. Estrogens (E) act as a strong inducer of uterine OT gene expression in vivo, and this effect is potentiated 7-fold by concomitant progesterone (P) administration. We have also cloned the rat OT receptor (OTR) gene and developed a polymerase chain reaction (PCR)-based assay to measure OTR mRNA. Whereas OTR mRNA is strongly induced by E, P does not potentiate but slightly attenuates the E-induced rise. However, E-induced OT binding is completely reversed by concomitant P administration, suggesting an additional post-transcriptional effect of P. The mechanisms of E-induction of the uterine OT gene remain unclear, inasmuch as the OTR gene promoter does not contain a classical estrogen response element (ERE). Moreover, transfection analysis of a 3.1 kb OTR gene promoter fragment linked to a luciferase reporter gene indicates that promoter activity is induced 5-fold by calcium ionophore A23187 but not by E.

Animals↗
PubMed1994

The effects of cigarette smoking on human gingival tissues (a histopathological study).

Gingival biopsy specimens were obtained from 9 smokers and 7 non-smokers during routine flap surgical procedure to investigate the effects of cigarette smoking on gingival epithelium and connective tissue. Although no remarkable histopathological difference was noted between gingival tissues of smokers and non-smokers, but smokers revealed relatively more epithelial keratosis, inflammatory cells, blood vessels and collagen fibres in connective tissue. Congestion of the capillaries were also more prominent in the smoker's gingival tissues.

Adult↗
PubMed1994

Neonatal cerebral candidiasis: CT findings and clinical correlation.

Lumbar puncture in a premature newborn undergoing therapy for sepsis revealed meningitis. Contrast-enhanced cranial tomography revealed multiple, homogeneously or ring-like enhanced lesions with peripheral edema. Cerebrospinal fluid culture showed growth of candida. Significant clinical recovery after Amphotericin-B treatment was noted. Follow-up CT examination showed regression of the lesions. Five months later no pathology was reported except small calcified granulomas and an area of encephalomalacia.

Amphotericin B↗
PubMed1993

Trends in cancer incidence and mortality.

Time trends in cancer risk have often been summarised by the observation that mortality from cancers associated with tobacco is increasing rapidly, while mortality from all other cancers is either stable or falling slightly, this slight decline being dominated by the decrease in mortality from stomach cancer. Until recently, and with some variation between the sexes, this simple summary of cancer mortality trends would have been broadly correct for a number of developed countries, and it remains useful in dismissing claims of an impending and unexplained epidemic of cancer, but it does not apply to all countries, and in some there have recently been striking changes in the trends in mortality from cancers associated with tobacco. Cancer mortality has been widely accepted as the most important measure of progress against cancer, since it reflects the impact of cancer on people, and has been considered less subject to distortion than incidence or survival, although this is open to question. Cancer mortality also reflects trends in incidence and survival to a greater or lesser extent. There has been controversy, however, over how cancer mortality trends should be interpreted, as well as over which measures should be used to assess progress in cancer control. An overall summary of trends in mortality from all cancers combined is of limited value in assessing progress against cancer, in any case. Increases in a common lethal cancer may numerically dominate overall mortality trends, perhaps concealing declines in less common or less lethal cancers, while opposite trends in cancers of the lung and stomach, for example, might lead to an overall impression that little has changed. Further, up to a third of cancer patients will not die of cancer, and cancer mortality statistics do not reflect their experience at all. Cancer mortality trends only indirectly reflect trends in the number of people who are diagnosed with cancer in a given year, and those who do die of cancer in a given year may have been diagnosed more than 3 years previously, even though many die earlier: this blurs the responsiveness of routine cancer mortality statistics as a measure of recent progress, and alternative measures have been proposed. Trends in competing risks of death, especially at higher ages, may also complicate the interpretation of cancer mortality trends. The chance of developing cancer, and in that event, the chances of surviving it, are of direct interest to individuals.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1989

Exposure to Legionellaceae at a hot spring spa: a prospective clinical and serological study.

Following the occurrence of five cases of Legionnaires' disease among patients and therapists at a French hot spring spa, a series of cleansing procedures and an epidemiological study were undertaken. During a 3-month period, the spring water was repeatedly sampled. Serum samples were taken from 689 randomly selected patients, 230 therapists, 134 administrative staff and a control group of 904 blood donors. Legionellaceae were present in the spring water at concentrations of 10(3)-10(5) colony forming units/l. Fifteen different species or serogroups were isolated with Legionella pneumophila serogroups 3 and 1 predominating. No clinical cases of Legionnaires disease were observed during the study. However, 11% of the therapists and 5% of the patients either had a high titre of antibody (greater than or equal to 256) to at least one species or serogroup or seroconverted during the study. Mean antibody titres in the three study groups were significantly higher than those in the blood donors against 11 of the 32 legionella antigens tested. Nine of these 11 antigens corresponded to species or serogroups isolated from the spring water. The highest mean antibody titres in all three study groups were against L. pneumophila serogroup 3, the most common legionella in the spring water. These findings have important implications for the maintenance of adequate standards of hygiene, bacteriological sampling and clinical surveillance in this and similar establishments.

Adult↗
PubMed1987

Tobacco smoking, occupational exposure and bladder cancer in Argentina.

The highest rate for bladder cancer in Latin America has been reported from La Plata, Argentina. A case-control study was carried out to investigate the reasons for this high rate. A total of 117 cases, 117 hospital controls and 117 neighbourhood sex- and age-matched controls were interviewed regarding their smoking and drinking habits and occupational exposures. Cigarette smoking and coffee drinking were identified as the major risk factors, and a significant association was also found for truck and railway drivers and for oil refinery workers. The relative risks for male smokers who ever smoked cigarettes vs. non-smokers was 4.3 (95% Cl: 1.9-10.3). The risk associated with black tobacco cigarettes was 2-3 times higher than that of blond cigarettes. For male ex-smokers the risk after 5 years of no smoking is less than one third of that of current smokers. The RR for drinking coffee was 2.4 (95% Cl: 1.4-4.4) after adjusting for the effects of tobacco smoking, and the risk increased with the number of cups per day. No association was found with the use of saccharin.

Age Factors↗
PubMedDate not supplied

Sonographically guided percutaneous treatment of hepatic hydatid cysts: long-term results.

PURPOSE: The purpose of this study was to evaluate the safety and efficacy of sonographically guided percutaneous drainage and irrigation of hepatic hydatid cysts. METHODS: Sixty-one patients with 84 hepatic hydatid cysts were treated using the puncture, aspiration, injection, and reaspiration (PAIR) technique under sonographic guidance. Patients with cysts larger than 6 cm in diameter underwent PAIR followed by percutaneous drainage (PAIR-PD). The cysts were sterilized by the injection of 1 of 2 scolicidal agents, 20% hypertonic saline solution (38 patients) or 0.5% silver nitrate (23 patients). All patients underwent follow-up examinations for 1 month-6 years after aspiration. Clinical and radiologic examinations and laboratory analyses were performed every month for the first 6 months and then at 3-month intervals. RESULTS: Serial sonographic examinations revealed a heterogeneous echo pattern in 78 cysts (93%); a progressive decrease in diameter in 76 cysts (90%); calcification of the cyst wall, cystic contents, or both in 10 cysts (12%); and complete disappearance of 1 cyst (1%) in a patient who had been monitored for over 6 years. Five patients developed urticaria, and 6 developed fever. One patient developed a biliary fistula after the first aspiration attempt. Two patients developed infection of the cyst cavity after PAIR-PD and were successfully treated with oral antibiotics. An anaphylactic reaction developed in 2 patients and was successfully treated with antiallergenic medication. No recurrence of hydatid disease after PAIR or PAIR-PD was observed in any patient over the follow-up period of 72 months (mean, 26 +/- 27 months). CONCLUSIONS: Percutaneous drainage of hydatid cysts is a safe, effective, and reliable treatment. Antiallergenic medication is required before PAIR or PAIR-PD. Both sclerosing agents, hypertonic saline and silver nitrate solutions, gave excellent results.

Adolescent↗
PubMedDate not supplied

A support vector machine using the lazy learning approach for multi-class classification.

Support vector machines can be used in a new machine learning technique based on statistical learning. In this paper, we develop least squares support vector machines (LS-SVMs) using the lazy learning approach to classify data in unclassifiable regions in the case of multi-class classification. LS-SVMs use a set of linear equations while SVMs use a quadratic programming problem. The lazy learning approach is a local and memory-based technique. Therefore, it is an alternative technique to fuzzy inference systems. Our studies show that LS-SVMs with the lazy learning approach can give comparable results to fuzzy LS-SVMs for multi-class classification.

Algorithms↗
PubMedDate not supplied

Comparison of blood flow velocities of the extraocular vessels in patients with pseudoexfoliation or primary open-angle glaucoma.

PURPOSE: To evaluate orbital blood flow velocities in patients with pseudoexfoliation glaucoma (PXG) or primary open-angle glaucoma (POAG). METHODS: Blood flow velocities in the ophthalmic, central retinal, and posterior ciliary arteries were evaluated by color Doppler imaging in 26 patients with PXG, 28 patients with POAG and 30 age-matched normal control subjects. The results were compared. RESULTS: Compared to the control subjects, patients with PXG showed statistically significant decreases in the mean peak systolic and end-diastolic velocities and increased mean resistive indices in all vessels except for the ophthalmic artery mean peak systolic velocity (p < 0.05). Patients with POAG, when compared to the control subjects, showed statistically significant decreases in the mean end-diastolic velocities and increased mean resistive indices in all vessels measured (p < 0.05). No statistically significant differences were found in the mean blood flow parameters between POAG and PXG. CONCLUSION: Blood flow velocities of the retrobulbar vessels are decreased in patients with PXG. Reduced blood flow velocities may be secondary as well as contributory to exfoliative glaucomatous damage. Although there was no significant difference in the mean blood flow parameters between POAG and PXG, alterations of retrobulbar vessels might be associated with different pathogenic mechanisms of PXG.

Aged↗
PubMedDate not supplied

Vaginal clear cell adenocarcinoma in an infant.

An infant girl who previously had hematuria was presented because of discharge of material from her genital area. Vaginal clear cell adenocarcinoma was diagnosed. Gynecological cancers in infant girls may be disclosed with hematuria.

Adenocarcinoma, Clear Cell↗