PubMed Health⌕ Search

Biomedical subjects

B Acar

Publications and source records attributed to B Acar.

10 recordsLinked to original sources
PubMed1999

SVD-based on-line exercise ECG signal orthogonalization.

An orthogonalization method to eliminate unwanted signal components in standard 12-lead exercise electrocardiograms (ECG's) is presented in this work. A singular-value-decomposition-based algorithm is proposed to decompose the signal into two time-orthogonal subspaces; one containing the ECG and the other containing artifacts like baseline wander and electromyogram. The method makes use of redundancy in 12-lead ECG. The same method is also tested for reconstruction of a completely lost channel. The online implementation of the method is given. It is observed that the first two decomposed channels with highest energy are sufficient to reconstruct the ST-segment and J-point. The dimension of the signal space, on the other hand, does not exceed three. Data from 23 patients, with duration ranging from 9 to 21 min, are used.

Algorithms↗
PubMed1998

Relation between bone mineral content and clinical, hormonal and biochemical parameters in postmenopausal women.

We studied factors related to bone mass after a natural or surgical menopause in 73 healthy women attending the menopause clinic of a university hospital. In the natural menopause group we found inverse correlations between bone mineral density (BMD) vs. menopausal duration; BMD vs. body mass index (BMI) and BMI vs. inorganic phosphate (Pi), borderline correlations between weight vs. thyroxin (T4) and weight vs. luteinising hormone (LH) and a positive correlation between androstenedione (D4A) vs. urinary calcium (Uca). In the surgical menopause group we found some negative correlations (BMD vs. menopausal duration, BMI vs. Pi; BMI vs. dehydroepiandrosterone sulphate (DS), weight vs. DS and cortisol vs. Uca) and some positive correlations (BMD vs. free testosterone (fT), BMD vs. calcium (Ca), and BMD vs. Uca). We concluded that the serum hormone levels we measured were not useful markers of current bone mineral status.

Adult↗
PubMed1995

Risk factors for Wolfe's dysplasia of mammograms in postmenopausal Turkish women.

OBJECTIVE: The aim was to ascertain whether menstrual, reproductive and hormonal risk factors for breast cancer are present in women with dysplastic mammographic patterns and to investigate possible trends towards breast cancer. METHOD: This prospective case-control study was designed in a university hospital. Thirty-two turkish postmenopausal women were evaluated for the associations between obesity, parity, age, age at menarche, age at menopause, total lactation period and dysplasic mammographic patterns. RESULTS: We found an increasing trend of dysplasia with increasing age at menarche. This association contradicts the well established one for breast cancer. The effects of parity and total lactation period on dysplasia were similar. Although nulliparity had some protective effects on dysplasia, relative risk (RR) increased to some extent with an increase in parity and lactation period. Later menopause and older age were associated with an increase risk of dysplasia, whereas an apparent protection was given by greater body mass index. CONCLUSION: Onset of the menopause increases the risk of dysplasia and the estrogenic milieu may have some role in the initiation and progression of dysplasia.

Aging↗
PubMed1994

Plasma copper, zinc and magnesium levels in patients with premenstrual tension syndrome.

We measured plasma Cu. Zn and Mg levels in 40 women suffering from premenstrual tension syndrome (PMTS) and in 20 control subjects by atomic absorption spectrophotometer. Mean plasma Cu, Zn and Mg levels, the Zn/Cu ratio were 80.2 +/- 6.00 micrograms/dl, 112.6 +/- 8.35 micrograms/dl, 0.70 +/- 0.18 mmol/l, and 1.40 +/- 0.10 in the PMTS group; and 77.0 +/- 4.50 micrograms/dl, 117.4 +/- 9.50 micrograms/dl, 0.87 +/- 0.10 mmol/l, and 1.51 +/- 0.05 in the control group respectively. The mean Mg level and the Zn/Cu ratio were significantly lower in PMTS patients than in the control group. Plasma Mg and Zn levels were diminished significantly during the luteal phase compared to the follicular phase in PMTS group. Mg deficiency may play a role in the etiology of PMTS.

Copper↗
PubMed1993

Diminished growth hormone responses to L-dopa in polycystic ovarian disease.

OBJECTIVE: To investigate the GH secretion capacity in polycystic ovarian syndrome (PCOS). DESIGN: Prospective. SETTING: Reproductive endocrinology unit. PATIENTS: Nineteen women with clinical and endocrinologic signs of PCOS were compared with 10 healthy weight-matched volunteers with normal menstrual rhythm and no history of endocrine or reproductive abnormality. INTERVENTIONS: Standard GH reserve estimates were affected in all subjects using oral L-Dopa. The test was carried out after an overnight fast on cycle days 5 to 8 in menstruating subjects; the test was done randomly in patients with amenorrhea. RESULTS: Both PCOS and control groups responded to L-Dopa over a 3-hour period with significant elevations in GH concentrations. The control group showed significantly higher values than the PCOS group at 90, 120, and 180 minutes. CONCLUSION: The findings indicate that PCOS patients demonstrate a relative deficiency in GH reserve.

Adolescent↗
PubMed1992

Diagnostic value of magnetic resonance imaging in gynaecology.

In this study 23 patients with various gynaecological pathologies were evaluated. Ultrasonography and magnetic resonance imaging were performed in all cases, but only 14 were evaluated with computed tomography. On the basis of ultrasonography, 4 patients were labelled as having malignant ovarian tumours, however, this diagnosis was confirmed by magnetic resonance imaging in only 1 of the 4. Magnetic resonance imaging also determined the correct diagnosis in a patient with endometrioma whereas computed tomography showed only a simple cyst, and ultrasonography diagnosed a subserous myoma. Tumour was demonstrated by magnetic resonance imaging in 2 patients with cervical carcinoma although computed tomography and ultrasonography had previously shown no tumour mass in these patients. It was concluded that magnetic resonance imaging is much superior to computed tomography and ultrasonography in gynaecological diagnosis. This advantage results from the correct detection of the contents of ovarian cysts, the number and localization of uterine leiomyomas in T2 scans, invasion of uterine malignancies and differential diagnosis of subserous uterine leiomyomas from ovarian tumours.

Adolescent↗
PubMed1989

Piperacillin alone vs triple antibiotic combination in gynecological infections.

Forty hospitalized adult patients with gynecological infections were randomly assigned to treatment either with piperacillin alone (22 patients) or with the combination of gentamicin, clindamycin and penicillin G (18 patients). The aim of the study was to investigate the possibility of replacing a triple combination therapy with a single-agent broad spectrum antibiotic. Penicillin G was added for the coverage of enterococci. The median duration of treatment was 8 days for both groups. The daily dose for the administered drugs was 12g for piperacillin, 4mg/kg for gentamicin, 1.8g for clindamycin and 20 million units for penicillin G. The cure-improvement rate in the single agent therapy group was 90.9% and in the combination therapy group 94.4%. These differences were not statistically significant. No side effects were reported. It is concluded that single agent piperacillin is as effective as the combination therapy used in this study for the treatment of hospitalized gynecological infections.

Adult↗
PubMed1981

Ovarian function in women immediately post partum.

Ovarian function in pregnant women at term was investigated by obtaining plasma samples from both ovarian veins simultaneously with a peripheral sample from the antecubital vein. All samples were analyzed by radioimmunoassay to determine the concentration of progesterone, estradiol, estrone, androstenedione, testosterone, and human chorionic gonadotropin. The corpus luteum was found to secrete progesterone and not significant amounts of estrogens or androgens. Extraluteal tissue secreted estrogens and androgens and also progesterone. No quantitative relationship was found between the concentrations of human chorionic gonadotropin and any ovarian steroid, and estradiol appeared to be produced from both estrone and testosterone.

Androgens↗