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Biomedical subjects

T Ozcan

Publications and source records attributed to T Ozcan.

18 recordsLinked to original sources
PubMed2001

Changes in fetal hemodynamics with ritodrine tocolysis.

OBJECTIVE: To evaluate the effect of ritodrine on the fetal cardiovascular system. METHODS: Cardiac and extracardiac Doppler waveforms were recorded in 12 fetuses prior to and during ritodrine therapy used for preterm labor. Maternal and fetal heart rates, the Doppler pulsatility indices of the umbilical artery, middle cerebral artery, descending thoracic aorta and renal artery, and time velocity integrals of the atrioventricular valves and the ductus arteriosus, were measured. RESULTS: Ritodrine infusion caused an increase in maternal and fetal heart rates, the left cardiac output as measured by the product of time velocity integral and heart rate, and the pulsatility index of the middle cerebral artery, and a decrease in the pulsatility index of the umbilical artery. CONCLUSIONS: Ritodrine infusion may alter placental and cerebral blood flow and may have a selective effect on the left side of the heart.

Cardiac Output↗
PubMed2000

Fetal arterial and venous Doppler parameters in the interpretation of oligohydramnios in postterm pregnancies.

OBJECTIVE: The objective of the current study was to evaluate fetal arterial and venous Doppler parameters in postterm pregnancies with oligohydramnios and those with normal amniotic fluid. STUDY DESIGN: A cross-sectional study was performed in 38 pregnancies beyond 41 weeks' gestation. Pulsed Doppler imaging was used to determine the pulsatility index (PI) for the fetal middle cerebral artery (MCA), renal artery, umbilical artery, inferior vena cava (IVC) and ductus venosus. The amniotic fluid index (AFI) was used for semiquantitive assessment of amniotic fluid volume. Oligohydramnios was defined as an AFI < 5 cm. RESULTS: Oligohydramnios was detected in 10 cases, and a normal AFI was present in 28 cases. In the presence of oligohydramnios the PI of the MCA was decreased, while the renal artery PI and the MCA PI/UA PI ratio were found to be elevated. In cases of oligohydramnios the PI in the IVC was increased but was unchanged in the ductus venosus. CONCLUSION: Oligohydramnios in post-term pregnancies is associated with arterial redistribution of fetal blood flow typifying the brain sparing effect and with decreased resistance in the MCA and increased resistance in the fetal IVC.

Arteries↗
PubMed2000

Cytogenetical diagnosis in paraffin-embedded fetoplacental tissue using comparative genomic hybridization.

Comparative genomic hybridization (CGH) is a FISH-related technique used to assess global chromosomal aberrations in a variety of human tumours. Recently CGH has been applied to cytogenetic analysis of fresh frozen fetoplacental tissues. Here we report the application of CGH to paraffin-embedded placental samples. Ten samples from paraffin-embedded blocks of 6 control placentas and fetoplacental tissue from 10 aneuploidies, and 2 unbalanced aberrations were evaluated. Balanced karyotype profiles were obtained from samples of healthy placentas and all samples from the same placenta appeared to have similar confidence intervals. CGH analysis of four cases of trisomy 21, three cases of trisomy 18, one case of trisomy 13, one case of trisomy 15 and one case of trisomy 7 all showed overrepresentation of the respective trisomic chromosome. The CGH profile was also in accordance with the karyotyping of a case with isochromosome 21. The CGH profile of a case with der (2)t(2;6)(q37.3;q22.2) revealed partial trisomy for chromosome 6 between q21 and q27. CGH may be a useful adjunct in prenatal genetic diagnosis when retrospective diagnosis is needed from archival samples.

Chromosome Aberrations↗
PubMed1998

Arterial and venous Doppler velocimetry in the severely growth-restricted fetus and associations with adverse perinatal outcome.

OBJECTIVE: To evaluate the association between arterial and venous Doppler waveforms and adverse perinatal outcome in severe intrauterine growth restriction. DESIGN: Fetuses between 26 and 32 weeks' gestation with ultrasonographically estimated fetal weight below the 5th centile were included in this prospective study. The last Doppler measurements of the umbilical artery, ductus venosus, umbilical vein and middle cerebral artery before delivery and adverse outcome parameters without gestational age independence were used for statistical analysis. Adverse outcome parameters were defined as the following: fetal demise or neonatal death in the first 30 days of life; 5-min Apgar score of < 7; intubation at birth; retinopathy of prematurity; respiratory distress syndrome; necrotizing enterocolitis; stay in neonatal intensive care unit of more than 60 days; intraventricular hemorrhage; periventricular leukomalacia. RESULTS: Nineteen fetuses fulfilled the inclusion criteria. Perinatal death, low 5-min Apgar values and necrotizing enterocolitis were gestational age-independent adverse outcome parameters. Abnormal Doppler velocimetry of the ductus venosus was the only significant parameter associated with perinatal death and low 5-min Apgar scores. None of the Doppler parameters predicted necrotizing enterocolitis. CONCLUSION: Our data suggest that management of severely growth-restricted fetuses may be aided by the study of ductus venosus Doppler velocimetry.

Blood Flow Velocity↗
PubMed1998

Effect of hysterectomy on ovarian blood supply and function.

Ovarian blood supply and function were assessed before and after hysterectomy in 43 patients and 30 healthy subjects (control group). Before the hysterectomy, transvaginal colour Doppler resistance index values of ovarian artery and hormonal levels were measured. Five days and 6 months after operation, all these measurements were repeated and compared with those of a control group. The sole hormone whose serum level decreased on the 5th postoperative day was oestradiol. Serum levels of all the other hormones remained unchanged 5 days and 6 months after the surgical operations. We also did not find any statistically significant difference between the preoperative, the postoperative and the control group resistance index of the ovarian arteries. We propose that the decision whether to preserve or remove the ovaries must be based on assessment of their functional status. Advantages and disadvantages of leaving ovaries intact should be carefully evaluated and the most useful approach applied to each patient on an individual basis.

Journal Article↗
PubMed1998

Can a single measurement of amniotic fluid delta optical density be safely used in the clinical management of Rhesus-alloimmunized pregnancies before 27 weeks' gestation?

BACKGROUND: To assess the efficacy of a single measurement of amniotic fluid optical density deviation at 450 nanometers in predicting fetal anemia in Rhesus-alloimmunization before 27 weeks gestation. METHODS: In this cross-sectional study, fetal blood and amniotic fluid samples from 43 Rhesus-alloimmunized pregnancies at 18 to 26 weeks gestation were obtained under ultrasound guidance. Amniotic fluid samples were scanned by spectrophotometry for optic density at various wavelengths. Deviation at 450 nanometers was calculated between 550 and 365 nanometers. The fetuses were divided into three groups based on their hematocrit levels and the predictive efficacy of optic density zones for anemia was evaluated. RESULTS: A high number of false positive and false negative results were observed when the delta-amniotic fluid optical density of fetuses at risk for anemia was plotted to the zones recently proposed to manage Rhesus-alloimmunized pregnancies. CONCLUSIONS: These data confirm previous results that the diagnosis of fetal anemia in Rhesus-alloimmunized pregnancies before 27 weeks' gestation cannot be accurately made by a single measurement of amniotic fluid optical density at 450 nanometers.

Amniocentesis↗
PubMed1997

The effect of intravascular blood transfusion on the flow velocity waveform of the portal venous system of the anemic fetus.

Our objective was to assess flow velocity waveforms of the portal venous system of the anemic fetus prior to and immediately following intravascular transfusion. Color-guided pulsed Doppler was used to obtain flow velocity waveforms from the fetal portal vein in 14 anemic fetuses that were transfused in utero for rhesus alloimmunization The portal vein velocity pattern was defined as continuous when no change in velocity during the cardiac cycle was noted. It was defined as pulsatile when a deflection of the wave was present. The flow velocity waveforms were quantified by using the ratio between the peak (highest, H) and the nadir (lowest, L) velocities (H/L ratio). Fourteen intravascular transfusions were performed. Gestational age ranged from 19.5 to 35 weeks (mean +/- SD, 26.7 +/- 5.3 weeks). The hematocrit ranged from 5.9 to 31.2% (mean +/- SD, 20.3 +/- 9%) prior to transfusion; after transfusion it was between 24.8 and 56.7% (mean +/- SD, 42 +/- 10.4%). In six cases (43%) the waveforms were pulsatile prior to transfusion; in the other eight (57%) they were continuous. The pulsatile pattern was present following transfusion in 13 cases (93%, p < 0.05). The mean of the H/L ratio was 1.3 +/- 0.38 prior to transfusion and 2.0 +/- 0.86 after transfusion (p < 0.05). Because the portal vein has continuous non-pulsatile flow in the normal fetus, the presence of pulsatility in the waves of six anemic fetuses (43%) may suggest portal hypertension. Compared to normal fetuses, there was an increased number of cases with pulsation, and even more so after transfusion. The pattern corresponds to findings in children with portal hypertension.

Anemia↗
PubMed1996

The effect of intraumbilical oxytocin on the third stage of labour.

The umbilical vein administration of oxytocin in saline was compared with umbilical vein saline alone and the traditional management of the third stage of labour. Seventy-two women were randomized to 3 groups. Group 1 received intraumbilical 20 IU of oxytocin diluted to 40 mL with saline. Group 2 received intraumbilical vein 40 mL of saline while subjects in group 3 were managed according to the standard protocol without any intraumbilical injection. No significant differences were found in terms of the length of the third stage, the blood loss in the third stage and postpartum haematocrit differences among the 3 groups. The administration of diluted oxytocin or saline do not seem to have any superiority to the traditional management of the third stage of labour.

Adult↗
PubMed1995

The concentration of plasma atrial natriuretic peptide in normotensive and preeclamptic pregnancies.

UNLABELLED: Atrial natriuretic peptide (ANP) is a family of peptides secreted by the heart, affecting the cardiovascular, renal and endocrine systems. This study questions previous research findings regarding elevated ANP levels, despite vasoconstriction and hypovolemia, in preeclamptic patients. MATERIALS AND METHODS: Seventeen patients with preeclampsia, 5 with superimposed preeclampsia with chronic hypertension and 17 normotensive pregnant women were compared with respect to plasma ANP levels. Seventeen non-pregnant women were taken as the control group. All the women, except the ones with superimposed preeclampsia, were age matched and in their third trimester. RESULTS: ANP levels in the non-pregnant women (6.9 +/- 0.7 pg/ml) were not different from those in the normotensive pregnant women (6.4 +/- 0.7 pg/ml). ANP levels were significantly higher in women with preeclampsia (10.8 +/- 1.8 pg/ml) or superimposed preeclampsia (9.7 +/- 1.4 pg/ml) than in normotensive pregnant women and normal non-pregnant women (P < 0.05). According to the literature, there is a volume depletion in preeclamptic women. However, this wasn't demonstrated in our study group. CONCLUSION: ANP levels in preeclamptic women were found to be higher than those in normotensive pregnant women. The etiology still remains obscure.

Adolescent↗
PubMed1995

Urinary calcium to creatinine ratio for predicting preeclampsia.

Urinary calcium excretion decreases in preeclampsia. To determine the predictability of preeclampsia with hypocalciuria, we investigated the calcium to creatinine ratio and the calcium level of a spot urine sample in 56 primigravid patients aged less than 25 years. Of these 56 cases, 44 remained normotensive and preeclampsia developed in eight cases. There were four cases of gestational hypertension and they are not included in the statistical analysis. The mean age, the mean gestational age at entrance into the study, the mean urine calcium concentration, the mean birthweight, and the mean gestational age at delivery were similar between the normotensive and preeclamptic groups. The mean calcium to creatinine ratio is found to be significantly lower in the preeclamptic group (0.0475 +/- 0.0260) compared with the normotensive group (0.1466 +/- 0.1353; p < 0.0001). A cutoff level of 0.066 for the calcium to creatinine ratio with the use of a receiver operator curve yielded a sensitivity of 75%, a specificity of 86%, and a positive and negative predictive value of 55% and 95%, respectively. The results of this study suggest that a single urine calcium to creatinine ratio might be an effective marker for predicting preeclampsia in a high-risk population.

Adult↗
PubMed1995

Ritodrine tocolysis and neonatal intraventricular-periventricular hemorrhage.

Betamimetic drugs are commonly used for tocolytic therapy. To determine their potential role in periventricular-intraventricular neonatal hemorrhage (IVH), 103 preterm births with cranial ultrasonography results were evaluated for the history of betamimetic therapy. The study group was divided into three subgroups according to the cause of the preterm delivery: 44 patients were accepted as tocolysis failure (group A); 53 patients were too late for tocolysis (group B), and these latter cases were taken as controls for group A; for the remaining 6 patients, tocolysis was contraindicated due to fetomaternal reasons (group C), and these cases were not included in the analysis. In group A, 32 patients got ritodrine, 6 patients got combined therapy including ritodrine plus magnesium sulfate or nifedipine. When cases in group A who got ritodrine only or combined therapy are compared with the no-treatment group, no significant difference in neonatal IVH incidences could be found (p > 0.005). Ritodrine does not appear to affect the incidence of neonatal IVH.

Cerebral Hemorrhage↗
PubMed1995

Change in atrial natriuretic peptide concentration after acute plasma volume expansion in normal pregnancy and preeclampsia.

Atrial natriuretic peptide (ANP) is found to be elevated in preeclamptic patients despite the presence of hemodynamic characteristics such as vasoconstriction and hypovolemia. In this study, the effect on ANP secretion of plasma volume expansion with crystalloid solutions was investigated. Seven preeclamptic and seven normotensive pregnant women in their last trimester were compared. After basal ANP measurements, 0.9% Ringer's solution, 15 cm3/kg body weight was infused within 30 min to expand the plasma volume. Blood sampling was repeated after the infusion. Maternal blood volume expansion was calculated from the decrease in hematocrit. Plasma ANP levels were corrected according to the degree of volume expansion. Basal mean levels in both groups were not different. Although the postinfusion levels of ANP in normotensive pregnant women were similar to the basal levels (means +/- SE: 20.6 +/- 0.41 and 27.2 +/- 0.52 pg/ml, respectively, p = 0.10), the postinfusion ANP levels in preeclamptic women increased significantly (21.4 +/- 0.31 and 34.1 +/- 0.28 pg/ml, respectively, p = 0.01). Preeclampsia is associated with a greater increase in plasma ANP levels in response to volume expansion compared with normotensive pregnancy. The greater change in the right atrial pressure with volume expansion, due to decreased compliance of the capacitance vessels in preeclamptic subjects might explain the greater change in the plasma level of ANP.

Adolescent↗
PubMed1994

Expectant management of functional ovarian cysts: an alternative to hormonal therapy.

OBJECTIVE: We studied whether the administration of oral contraceptives facilitates the disappearance of spontaneously formed functional ovarian cysts. METHODS: Eighty patients in whom ultrasonography revealed unilateral, mobile, unilocular, thin-walled ovarian cysts without internal echoes and greater than 30 mm but not exceeding 60 mm in diameter were enrolled into the study. Patients were randomized by stratification to receive a low-dose monophasic pill, a high-dose monophasic pill, a multiphasic pill or no therapy. Patients were re-evaluated after 5 weeks of therapy and at the end of therapy (10 weeks). RESULTS: The mean ages and the mean cyst diameters of the patients for each group were not significantly different. We did not find a significant effect of oral contraceptive administration on the disappearance rate of functional ovarian cysts over that of expectant management. CONCLUSION: We conclude that oral contraceptive therapy even with multiphasic pills is very effective in the management of functional ovarian cysts but expectant management achieves similar success rates and may be a good alternative to oral contraceptive therapy.

Adult↗
PubMedDate not supplied

Increase of fetal hematocrit decreases the middle cerebral artery peak systolic velocity in pregnancies complicated by rhesus alloimmunization.

Our hypothesis for this study was that an increase in fetal hematocrit would decrease the middle cerebral artery peak systolic velocity. Seventeen pregnancies complicated by Rh alloimmunization were included in this study. Middle cerebral artery peak systolic velocity was studied by Doppler ultrasound before and after intrauterine transfusion with adult packed red blood cells (hematocrit = 80-85%). Mean gestational age at time of study was 27 weeks. Paired t-test was used for statistical comparison. A P value of < 0.05 was considered statistically significant. The fetal hematocrit ranged from 5.9% to 30% prior to the procedure, and it was 24.8-53.4%, following the procedure. Mean middle cerebral artery peak systolic velocity was 46.2 +/- 10.7 cm/s prior to the procedure, and it decreased to 31.7 +/- 9.5 cm/s following the procedure (P < 0.01). The increase of fetal hematocrit significantly decreases the middle cerebral artery peak systolic velocity supporting data that this Doppler measurement may be useful for the diagnosis of fetal anemia.

Anemia↗