Search PubMed⌕ Search

Biomedical subjects

A Sahin

Publications and source records attributed to A Sahin.

At least 73 records · Page 4Linked to original sources
PubMed1997

The prognostic significance of sialyl-Tn antigen in women treated with breast carcinoma treated with adjuvant chemotherapy.

BACKGROUND: Sialyl-Tn (STn) represents an aberrantly glycosylated mucin epitope that is expressed in breast carcinoma and other adenocarcinomas and is an important factor in the development of novel immunotherapeutic approaches. The primary aim of the current study was to investigate the influence of STn expression on the prognoses of patients with breast carcinoma. METHODS: A cohort of 207 women diagnosed with invasive breast carcinoma who were treated with anthracycline-containing adjuvant chemotherapy and were enrolled in a randomized clinical trial were studied. Expression of STn was determined by an immunohistochemical procedure in which the B72.3 monoclonal antibody was used. Kaplan-Meier and Cox proportional regression survival analyses were used to compare low STn and high STn patients. RESULTS: Forty-eight (23%) of the 207 specimens demonstrated high STn staining (>25% cells were immunoreactive). During a median follow-up of 5 years, high STn patients had worse disease free survival than low STn patients (55% vs. 74%, respectively; P = 0.03). High STn expression was significantly associated with age (P = 0.04) but not with other conventional prognostic markers. In multivariate analysis using the Cox regression model, high STn emerged as an independent prognostic indicator for disease free survival (hazard ratio [HR], 2.02; 95% confidence interval [CI], 1.09-3.73) and for overall survival (HR, 2.16; 95% CI, 0.95-4.92). CONCLUSIONS: The results of this study suggest that STn may be a valuable marker for identifying women at high risk of developing recurrent breast carcinoma who may be candidates for trials investigating new therapies in combination with standard adjuvant therapy.

Adult↗
PubMed1997

Ureteroscopic management of lower ureteral stones: two years' experience.

A total of 140 ureteroscopies in 119 patients done between January 1992 and December 1994 at the Department of Urology, Hacettepe University Hospital, were reviewed. Factors such as previous ESWL therapy, previous surgery and use of in situ lithotripsy were noted. Success was defined as complete removal or disintegration and partial removal of the lower ureteral stones. All successes were confirmed by plain abdominal X-rays postoperatively. Of 140 stone manipulations attempted in 119 patients 106 (75.7%) were successful (in 80 by retrieval and in 26 by disintegration using electrohydraulic or laser). Perforation occurred in 4 of 13 cases where electrohydraulic lithotripsy was used for disintegration of stones. Extraction by ureteroscopic manipulation following extracorporeal shock wave lithotripsy (ESWL) was successful in all of the 12 cases of lower ureteral calculi. The success rate was found to be low for lower ureteral stones in patients with previous open surgery (2/9). A total of 43.2% of the patients were medically indicated to be hospitalized following the procedure with a mean hospitalization time of 5 days (ranging in between 1 to 7 days). Ureteroscopy is an effective method for management of lower ureteral stones. Use of the electrohydraulic lithotriptor may be associated with a high percentage of complications. Previous ESWL may be associated with a high rate of success. Results in patients with previous open surgery are not encouraging. Although all patients can be subjected to the procedure on an outpatient basis, a significant percentage need a short hospitalization.

Adult↗
PubMed1997

The effect of alternate-day low dose prednisolone on bone age in children with steroid dependent nephrotic syndrome.

Radius, ulna, short bones (RUS), carpal (CARP) bone age (BA), tibial cortico-diaphyseal (C/D) ratio and trabecular aspect were assessed in 19 children with steroid dependent nephrotic syndrome and 15 age matched healthy children. Both RUS and CARP BA were significantly lower than in the controls. Trabecular aspect and tibial C/D ratio did not show any statistical significance. There was a positive correlation between HSDS and RUS BA delay (r = -0.476, p < 0.05); CARP BA delay and RUS BA delay (r = 0.563, p < 0.01) and RUS BA and CARP BA (r = 0.891, p < 0.001). In conclusion, RUS and CARP BA are both retarded and positively correlated in steroid dependent nephrotic children.

Age Determination by Skeleton↗
PubMed1997

The effect of metabolic acidosis on serum apolipoprotein A I and apolipoprotein B levels in children with chronic renal failure.

In this report serum apolipoprotein A I (Apo A I) and apolipoprotein B (Apo B) levels were determined in children with chronic renal disease (CRD) during metabolic acidosis, after the correction of metabolic acidosis and in healthy children to look for the effect of metabolic acidosis on Apo A I and B levels. It was found that Apo A I levels were significantly decreased during metabolic acidosis (p < 0.05) but Apo A I/Apo B ratios were not affected before and after the correction of acidosis in the CRD group (p > 0.05) although it was significantly different from those in the controls (p < 0.01).

Acidosis↗
PubMed1997

Unusually located hydatid cysts: intrathoracic but extrapulmonary.

BACKGROUND: Hydatid cyst disease is still a problem in Turkey, as well as in many other places in the world. Extrapulmonary location of the disease in the thorax is very rare, and surgical procedures can be considered that differ from those used for pulmonary hydatid cysts. METHODS: We reviewed retrospectively our experience in the surgical treatment of 22 patients with intrathoracic, extrapulmonary hydatid cysts. In our department, 297 patients with thoracic hydatid cysts were managed surgically in the last 14 years, in 22 (7.4%) of whom the cysts were localized extrapulmonarily in the thorax. The locations of these hydatid cysts were a fissure, the pleural cavity, chest wall, mediastinum, myocardium, and diaphragm. RESULTS: Total resection was chosen as the surgical procedure in all patients except 4 (18.2%), 1 of whom had cystectomy and capitonnage for cardiac hydatid cyst and 3 of whom had cystectomy and local curettage for cysts located in the chest wall. Empyema developed postoperatively in 1 case (4.5%) with a cyst in the fissure. The follow-up period was 1 year, and there were no deaths. CONCLUSIONS: Hydatid cyst may be found in many different sites, including extrapulmonarily in the thorax, and bearing this in mind will facilitate planning of the operation.

Adolescent↗
PubMed1997

Dexamethasone and flumethasone residues in milk of intramuscularly dosed cows.

A field study was performed to assess the level of drug residues in milk after therapeutic application of highly potent synthetic glucocorticoids. Dexamethasone was tested either as a crystalline suspension or as a combination of sodium phosphate and phenylpropionate esters. Intramuscular injection of these preparations in lactating dairy cows (60 micrograms dexamethasone/kg body wt) yielded drug residues in milk of up to 8.4 ng/mL 12 h after treatment. These dexamethasone residues fell to below 1.0 ng/mL within 3 days after treatment. Intramuscular injection of an aqueous flumethasone preparation (13.5 micrograms/kg body wt) produced drug residues in milk in the range of 0.7-1.2 ng/mL 12 h after treatment, whereas flumethasone was below the detection limit of 0.23 ng/mL 2 days after administration. These results indicate that toxicologically significant residues may arise transiently in the milk during the first 2-3 days after intramuscular injection of synthetic glucocorticoids. Urine from the same animals contained 5- to 50-fold higher glucocorticoid concentrations than the corresponding milk samples. Thus, urine analysis appears to be an effective method to monitor the use of synthetic glucocorticoids in food producing animals.

Animals↗
PubMed1997

A modified BEP protocol: reduction of hospitalization without reducing the efficacy.

OBJECTIVE: We have aimed at assessing whether a condensed bleomycin/etoposide/cisplatinum (BEP) regimen would be as effective as the conventional protocol in the treatment of patients with metastatic testicular tumors. METHODS: Sixty-four consecutive patients with metastatic germ cell testicular tumors were included into this modified BEP protocol between April 1991 and January 1995. The condensed regimen consisted of a single daily dose of cisplatin (100 mg/m2) and bleomycin (30 mg) plus 3 consecutive days of etoposide (150 mg/m2). RESULTS: Of the 64 patients, 34 (54%) achieved a complete response with chemotherapy alone. An additional 23 (35%) patients in addition to chemotherapy have undergone surgery and became tumor free after resection of the residual masses and additional chemotherapy. The mean hospitalization period of 64 patients who received a total of 289 therapy courses was 65.4 (49-192) h for each course. The creatinine clearances did not differ significantly before and after treatment in neither of the chemotherapy courses. CONCLUSIONS: We would thus like to suggest that this condensed BEP protocol is cost-effective and improves patient compliance and quality of life. Furthermore, this is achieved with comparable efficacy to conventional therapy without increasing the toxicity. However, prospective randomized trials with similar results are needed to determine the efficacy of this regimen, and only then this regimen may replace the conventional therapy.

Adult↗
PubMed1997

Quantitative evaluation of renal parenchymal mass with 99mtechnetium dimercapto-succinic acid scintigraphy after nephrolithotomy.

PURPOSE: We detected renal parenchymal damage after nephrolithotomy. MATERIALS AND METHODS: We studied 12 patients with renal stones treated with nephrolithotomy. Renal function was determined with serum blood urea nitrogen (BUN) and creatinine values, and 99mtechnetium dimercapto-succinic acid scintigraphy of renal parenchymal tissue was performed before, and 7 days and 3 months after nephrolithotomy. Qualitative and quantitative analyses were done with the Wilcoxon signed rank test. RESULTS: There was no visual difference in size and appearance of the nephrotomy site between preoperative and postoperative visual scintigraphic evaluations. Quantitative data did not reveal any significant difference between kidneys with and without a nephrotomy incision (p > 0.05), as well as between nephrotomy regions and intact parenchyma within the same kidney (p > 0.05) 3 months after nephrolithotomy. There was no significant difference in serum BUN and creatinine levels between values preoperatively and 3 months postoperatively (p > 0.05). CONCLUSIONS: There was no significant change in renal cortical function and functioning renal parenchymal mass after nephrolithotomy as shown by serum BUN and creatinine levels, and 99mtechnetium dimercapto-succinic acid scintigraphy.

Adolescent↗
PubMed1997

Intraluminal crystalloids in breast carcinoma. Immunohistochemical, ultrastructural, and energy-dispersive x-ray element analysis in four cases.

OBJECTIVE: Intraluminal crystalloids have been described in the prostate, salivary gland, and ovary, but have not yet been reported in the breast. We report four cases of breast carcinoma in which these crystalloids were found in ducts with intraductal carcinoma or atypical hyperplasia. The presence of intraluminal crystalloids may be a useful adjunct in making a diagnosis of carcinoma or may be a feature to look for as a marker for the presence of carcinoma. DESIGN: Four cases of breast carcinoma containing intraluminal crystalloids were identified among 6900 surgical breast specimens between January 1990 and June 1995 at M. D. Anderson Cancer Center, Houston, Tex. Those sections with crystalloids identified by hematoxylin-eosin stain were stained with periodic acid-Schiff, Alcian blue, and mucicarmine stains. Immunohistochemical and ultrastructural studies and energy-dispersive x-ray analysis were also performed on these sections. RESULTS: The intraluminal crystalloids were eosinophilic, varied in shape and size, and did not exhibit birefringence under polarized light. Immunohistochemically, the crystalloids were negative for keratin, muscle-specific actin, and kappa and lambda light chains, but the surfaces stained positively for epithelial membrane antigen. By electron microscopy, the crystalloids had no limiting membrane and were composed of an electron-dense material with no discernible periodicity. By energy-dispersive x-ray element analysis, the crystalloids had no mineral content; however, sulfur was found, indicating a protein content. CONCLUSIONS: The pathogenesis and constituents of these intraluminal crystalloids remain to be determined. Inasmuch as intraluminal crystalloids have not been found in normal ducts or acini, or in ductal hyperplasia without atypia, their presence may serve as a marker for breast carcinoma.

Adult↗
PubMed1997

[Sudden death of Alpine cattle in the canton Graubünden].

The aetiology of sudden deaths of cattle in the Kanton Graubünden has been elucidated by a multi-disciplinary approach. Certain small rivers and ponds located in the affected Alpine pastures in the areas of Misox, Rheinwald and Engadin provide favourable habitats for the growth of hepatotoxic cyanobacteria, particularly during long periods of hot and dry weather. As cattle frequently take up water from these sources, the toxins produced by cyanobacteria may lead to lethal poisonings that are typically associated with hemorrhagic liver necrosis. The latest reported case of cyanobacteria poisoning of Alpine cattle occurred during the summer of 1996. Further animal losses may be avoided by the implementation of appropriate pasture management schemes. To identify sites of potential hazards to human or animal health, we have developed a sensitive screening assay for the detection of cyanobacteria hepatotoxins in algae and water samples.

Animals↗
PubMed1997

Analysis of telomerase activity levels in breast cancer: positive detection at the in situ breast carcinoma stage.

Telomerase activity has been implicated to be associated with most human malignant tumors, including breast cancer. To evaluate possible associations with well-known prognostic factors in breast cancer, we performed a semi-quantitative analysis of telomerase activity levels using the very sensitive PCR-mediated telomeric repeat amplification protocol. Telomerase activity was detected in 99 of 104 breast cancer samples analyzed (95.2%), whereas no activity was detected in 10 of 10 adjacent nonmalignant breast tissues. Analysis of five breast fibroadenoma samples revealed telomerase activity in one (20%). In contrast to previous observations, we observed that 100% of stage I breast tumors were positive for telomerase activity. More interestingly, we detected telomerase activity in six of six ductal carcinoma in situ samples (i.e., stage 0). In our semiquantitative analysis of levels of enzymatic activity, we found no statistically significant correlation at the P < h 0.05 level between telomerase levels and lymph node metastasis status, estrogen and progesterone receptor status, tumor size, S-phase fraction, and ploidy. The only statistically significant correlation was found with patient age (rho = -0.3; P = 0.03). We observed no statistically significant difference in the telomerase activity levels of early tumors (stages 0 and 1) versus more advanced lesions (stages II to IV). Nevertheless, stage IV tumors displayed a tendency for higher telomerase activity levels. In summary, no clear association was observed between telomerase levels and known breast cancer prognostic indicators. However, telomerase detection by the telomeric repeat amplification protocol method, due to its high sensitivity, may be of value in early breast cancer diagnosis and detection, because our data indicate that telomerase reactivation appears to constitute a relatively early event in breast carcinogenesis.

Biomarkers, Tumor↗
PubMed1996

Deletion map of chromosome 16q in ductal carcinoma in situ of the breast: refining a putative tumor suppressor gene region.

Allelic losses or imbalances affecting chromosome arm 16q appear to be early genomic abnormalities in breast carcinogenesis, because they were observed in a significant number of breast ductal carcinoma in situ lesions in our previous study (Aldaz et al., Cancer Res., 55: 3976-3981, 1995). To define the minimum region of loss of heterozygosity (LOH), we generated a high-resolution allelotype of 35 ductal carcinoma in situ cases and completed a deletion map of chromosome 16q by means of paraffin-embedded tissue microdissection and PCR microsatellite analysis of 22 markers. We observed a strikingly high frequency of LOH in 16q, with 31 of 35 tumors (89%) affected. We identified three distinctive areas with high LOH. Two areas were described previously and correspond to 16q21 and 16q24.2-qter. The third and most commonly affected area spanned the region from marker D16S515 to marker D16S504. The most affected locus was at D16S518, in which LOH was observed in 20 of 26 informative cases (77%), and we estimate that it lies in subregion q23.3-q24.1. The region of highest LOH spanned approximately 2-3 Mb, as determined by a yeast artificial chromosome contig reported to cover this region. Such a high frequency of LOH at a preinvasive stage of breast cancer suggests that a candidate tumor suppressor gene or genes at this location may play an important role in breast carcinogenesis.

Autoradiography↗
PubMed1996

Biliary excretion of biochemically active cyanobacteria (blue-green algae) hepatotoxins in fish.

Previous reports demonstrated that microcystin and related cyanobacteria polypeptides are rapidly cleared from plasma and accumulate in liver tissue. In the present study, we have used their ability to inhibit protein phosphatases to show that these cyanobacteria hepatotoxins are excreted into the bile of experimentally poisoned rainbow trout. At various times after oral administration of hepatotoxic Microcystis aeruginosa, bile samples were analysed for microcystin content by methanol extraction and protein phosphatase assays. An inhibitory principle that specifically suppressed protein phosphatase activity was detected in all bile samples removed between 1 and 72 h after oral exposure to toxic algae. These results indicate that biochemically active microcystin molecules are excreted into the biliary tract of poisoned fish.

Animals↗
PubMed1996

Technical approach for the study of the genetic evolution of breast cancer from paraffin-embedded tissue sections.

We have optimized a technique that allows the study of numerous chromosomal loci (n = 20-50) from single paraffin-embedded tissue sections by microsatellite length polymorphism analysis. DNA samples from normal and breast cancerous tissue can be obtained from the same section by means of microdissection. This technique was further improved by subjecting DNA to several cycles of amplification with a degenerate (universal) primer and then with specific microsatellite primers. This amplified DNA was also used to screen for mutations in the p53 gene by means of PCR-SSCP. In addition adjacent tissue sections were used to assess specific chromosome copy number by interphase cytogenetic analyses (chromosome in situ hybridization) and to analyze expression of specific genes such as p53 and ERBB2. As an example of the use of our approach we performed a detailed chromosome 17 allelotypic analysis in 22 breast tumors (5 ductal carcinomas in situ, 13 invasive ductal carcinomas, and 4 invasive lobular carcinomas). We detected mutations in the p53 gene by PCR-SSCP in 36% of the samples. Samples with significant levels of p53 protein accumulation detected by immunohistochemistry were also positive for mobility shifts in the SSCP analysis. We observed that chromosome 17 allelic losses and imbalance occurred at as early a stage as ductal carcinoma in situ (DCIS). Although in some cases we observed allelic losses or imbalance affecting the 17p13 region, close to the p53 locus, several of the tumors showed dissociation between such loss or imbalance and p53 mutation. Lobular carcinomas were predominantly disomic for chromosome 17 in contrast with ductal tumors, which often showed polysomy for chromosome 17. This comprehensive approach correlating the tumor subtype, its allelotype, with specific chromosome copy number and specific gene mutations and expression in preinvasive or early invasive breast cancer lesions will potentially provide information of relevance for a better understanding of the multistep mechanisms of breast carcinogenesis.

Alleles↗
PubMed1996

Interphase cytogenetics in mammographically detected breast lesions.

Chromosomal aneuploidy in 25 mammographically detected breast lesions (MDBL) were determined on cytological smears using directly labeled pericentromeric probes for chromosomes 7 to 12, 17, 18 and X. The lesions included seven nonproliferative (NP) lesions, seven atypical hyperplasias (AHs), and 11 carcinomas (CAs). No other significant histological findings were identified in the remaining specimens except in two mammographically detected NP lesions, where foci of AH were present in adjacent sections; therefore, these two specimens were included in the AH lesion group (moderately increased risk lesions). Corresponding tissue sections were evaluated, and the results were correlated with fluorescent in situ hybridization (FISH) results. Monosomy was defined as the loss of one signal in > or = 15% of cells, and trisomy or tetrasomy was defined by the presence of three or more signals in > or = 3% of cells. Chromosomal aberrations were detected in 2 of 5 NP, 9 of 9 AH, and 11 of 11 CA groups. The mean number of cells with three or more signals, for all chromosomes, was 1.04 +/- 0.9 in the NP group, 8.5 +/- 9.4 in the AH group, and 20.2 +/- 5.4 in the CAs. A significant statistical difference was noted between the different groups (P = .0001). Chromosomal gain was the most common aberration and involved all chromosomes. The X chromosome was the only individual chromosome with significant differences in NP, AH, and CA groups. Chromosomal loss was observed in five specimens (20%) and involved chromosomes 8, 10, 17, and 18. The authors conclude (1) significant chromosomal aberrations can be detected in AH lesions and in NP epithelium from patients with moderately increased risk lesions; (2) numerical chromosomal aberrations tend to increase with progression of disease; (3) the frequent chromosomal gains/losses involving AH suggest that some AH may display submicroscopic features of malignancy; and (4) combined chromosomal aberrations allow for significant categorization of breast lesions, especially in cytology specimens.

Adult↗