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Biomedical subjects

S Ozer

Publications and source records attributed to S Ozer.

At least 37 records · Page 2Linked to original sources
PubMed1999

Volatile anesthetics increase intracellular calcium in cerebrocortical and hippocampal neurons.

BACKGROUND: An increase in intracellular calcium concentration ([Ca2+]i) in neurons has been proposed as an important effect of volatile anesthetics, because they alter signaling pathways that influence neurotransmission. However, the existing data for anesthetic-induced increases in [Ca2+]i conflict. METHODS: Changes in [Ca2+]i were measured using fura-2 fluorescence spectroscopy in rat cortical brain slices at 90, 185, 370, and 705 microM isoflurane. To define the causes of an increase in [Ca2+]i, slices were studied in Ca2+-free medium, in the presence of Ca2+-channel blockers, and in the presence of the Ca2+-release inhibitor azumolene. The authors compared the effect of the volatile anesthetic with that of the nonanesthetic compound 1,2-dichlorohexafluorocyclobutane. Single-dose experiments in CA1 neurons in hippocampal slices with halothane (360 microM) and in acutely dissociated CA1 neurons with halothane (360 microM) and isoflurane (445 microM) also were performed. RESULTS: Isoflurane at 0.5, 1, and 2 minimum alveolar concentrations increased basal [Ca2+]i in cortical slices in a dose-dependent manner (P < 0.05). This increase was not altered by Ca2+-channel blockers or Ca2+-free medium but was reduced 85% by azumolene. The nonanesthetic 1,2-dichlorohexafluorocyclobutane did not increase [Ca2+]i. In dissociated CA1 neurons, isoflurane reversibly increased basal [Ca2+]i by 15 nM (P < 0.05). Halothane increased [Ca2+]i in dissociated CA1 neurons and CA1 neurons in hippocampal slices by approximately 30 nM (P < 0.05). CONCLUSIONS: (1) Isoflurane and halothane reversibly increase [Ca2+]i in isolated neurons and in neurons within brain slices. (2) The increase in [Ca2+]i is caused primarily by release from intracellular stores. (3) Increases in [Ca2+]i occur with anesthetics but not with the nonanesthetic 1,2-dichlorohexafluorocyclobutane.

Anesthetics, Inhalation↗
PubMed1999

Oro- and nasogastric tube passage in intubated patients: fiberoptic description of where they go at the laryngeal level and how to make them enter the esophagus.

BACKGROUND: Insertion of a gastric tube (GT) in anesthetized, paralyzed, and intubated patients can be difficult The purpose of this study was to determine fiberoptically why GTs succeed or fail to enter the esophagus and, based on these findings, to determine a mechanism for converting failures into successes. METHODS: Sixty patients under general anesthesia and orotracheally intubated were studied. The larynx and hypopharynx of each patient were viewed via a fiberscope placed through the left naris. GTs were passed orally (OGT) and nasally (NGT) in all patients, and the pathway of passage or site of resistance was visualized. In cases of resistance, medially directed ipsilateral neck pressure was applied over the lateral thyrohyoid membrane (termed lateral neck pressure) to try to allow passage of the GT. RESULTS: All 60 patients had both an OGT and NGT passed for a total of 120 attempts. The GT passed easily on the first attempt in 92 of 120 insertions (77%) (for OGT 51/60 = 85% and for NGT 41/60 = 68%, P < 0.05). In 92% of these first-pass successes, the GT entered the hypopharynx just lateral to the arytenoid cartilages. The GT met resistance and failed to pass in 28 of 120 insertions (23%) (for OGT 9/60 = 15% and for NGT 19/60 = 32%). The sites of impaction were the piriform sinuses (13/28 = 46%), arytenoid cartilages (7/28 = 25%), and trachea (6/28 = 21%), and two OGTs did not pass the oropharynx (2/28 = 70%). Lateral neck pressure was attempted 20 times (for the piriform sinus and arytenoid cartilage impactions) with 17 successes (85%) and three failures (15%). The average distance to passage of the OGT and NGT by the arytenoid cartilage was 13.2 and 16.2 cm, respectively. CONCLUSION: GTs enter the hypopharynx just lateral to the arytenoid cartilages. Consequently, the most common sites of resistance at the laryngeal level are the arytenoid cartilages and piriform sinuses. Lateral neck pressure compresses the piriform sinuses and moves the arytenoid cartilages medially, relieving 85% of these GT impactions.

Adult↗
PubMed1998

Does large-bowel enema reduce septic complications in acute pancreatitis?

BACKGROUND: The source of septic complications in acute pancreatitis was unknown until recent years. The pathogenesis of bacterial translocation from the gut has been accepted as the main source of pancreatic or peripancreatic infection. This study was designed to investigate the role of large bowel enema during acute pancreatitis in preventing bacterial translocation. MATERIALS AND METHODS: Twenty-four Spraque-Dawley rats were used in this study. The rats were divided into two groups. Group I animals received biliopancreatic duct ligation plus colon cleansing by rectal enemas; group II animals received only biliopancreatic duct ligation. Rectal enemas were applied to the first group of animals three times, at 6, 24, and 48 hours after the operation using 10 cc sodium hydrogen phosphate solutions. All animals were sacrificed 72 hours later, and tissue samples were taken from mesenteric lymph nodes, pancreas, spleen, and liver for bacteriologic cultures via a midline laparatomy. Blood and cecum cultures were also prepared. RESULTS: Positive mesenteric lymph node cultures were found in all 12 animals in group II but in only 3 of 11 animals of group I (P <0.05). Distant organ cultures were positive in 9 of group II, but the only infected distant organ culture found in group I was the positive liver culture (P <0.05). CONCLUSION: As a result of this study, we believe that large bowel enema can reduce the frequency of septic complications in acute pancreatitis by reducing bacterial translocation.

Acute Disease↗
PubMed1998

The derivation of theoretical ultrasonic Doppler blood flow spectrum.

This paper deals with theoretical aspects of blood flow and the ultrasonic Doppler spectrum. Blood flow in the vessel can be considered as a pipe flow with a circular cross-section. Blood flow is, in general, complex and pulsatile. Navier-Stokes and the continuity equations are the governing equations for the blood flow, and the Navier's equations for the blood vessel. If the flow is pulsatile with a large Womersely number, the velocity profile becomes blunt due to the inertia forces. Since the ultrasonic Doppler flowmeter detects the velocities of blood cells across the vessel, Doppler power spectrum is dependent on the velocity profile. If the velocity profile is blunt, the Doppler power spectrum will be narrow banded. If the flow is sinusoidal, the Womersely number is only a parameter describing the pulsatility. Blood flow waveforms, however, differ from the sinusoidal wave. They consist of a steady flow component and many harmonics with amplitudes and phases. In this study, the influence of the harmonic contents and the Womersely number on velocity profiles and the Doppler power spectrum are examined.

Algorithms↗
PubMed1998

Posterior approaches in groin hernia repair with prosthesis: open or closed.

UNLABELLED: Laparoscopic herniorraphies have been used to reduce the pain and convalescence associated with open approaches. However, there is still not any consensus of the best approach. We compared open preperitoneal and laparoscopic total extraperitoneal approaches in groin hernia repair. METHODS: Thirty-two patients underwent open preperitoneal herniorraphy (Group I) and other 32 patients underwent total extraperitoneal repair (Group II). Time of surgery was noted. Visual Analogue Scale (VAS) was applied to evaluate the postoperative pain intensity. RESULTS: Operation time was 35 (20-65) minutes in Group I and 58 (40-85) minutes in Group II (p < 0.05). The difference of complication ratios between two groups was not significant. Laparoscopic approach was associated with less pain within postoperative 24 hours as compared to the open technique. However, after the first postoperative day, there was no longer statistically significant difference between both groups. No recurrence has yet been seen in follow-up period of 15 (4-24) months. CONCLUSION: Laparoscopic herniorraphy is associated with better results in term of postoperative pain within the first 24 hours as compared to open technique.

Adult↗
PubMed1997

The role of serotonin re-uptake inhibitors in preventing recurrent unexplained childhood syncope -- a preliminary report.

UNLABELLED: To assess the efficacy of a serotonin re-uptake inhibitor, sertraline hydrochloride, in preventing recurrent neurocardiogenic syncope, we studied 15 patients (10 female; mean age 12.9 +/- 2 years) with positive head-upright tilt test and resistant to standard pharmacotherapy, atenolol or disopyramide. The patients were given 50 mg oral sertraline hydrochloride daily for 6 weeks. Intolerance to the drug was seen in 3 patients and 2 had syncopal episodes during the therapy. A head-upright tilt table test was then repeated in 10 patients. Six were tilt negative and asymptomatic over a mean follow up period of 7 +/- 3 months while four remained tilt positive: two experienced marked hypotension and bradycardia, characterized as mixed type syncope, and two had cardiac asystole, lasting > 10 s, during tilting, thereby exhibiting a cardio-inhibitory response. CONCLUSION: Sertraline hydrochloride may be useful in preventing recurrent neurocardiogenic syncope resistant to standard pharmacotherapy but careful clinical studies are essential before such a treatment strategy can be recommended since serious asystole could develop.

1-Naphthylamine↗
PubMed1997

Relation of dietary restraint to bulimic symptomatology: the effects of the criterion confounding of the Restraint Scale.

Studies indicate that various measures of dietary restraint show inconsistent relations to bulimic symptomatology. The present study tested the assertion that this is because the scales differ in the extent to which they reflect the success or failure of dietary efforts. This study also tested the competing hypothesis that criterion confounding of the Restraint Scale produced the inconsistent findings. Data from 117 undergraduates indicated that both the Restraint Scale and the Dutch Restrained Eating Scale were correlated with bulimic pathology, but that the magnitude to the relations were higher for the former. These results supported the dietary success failure hypothesis, however, this difference disappeared when the two disinhibited eating items from the Restraint Scale were deleted. Thus, the inconsistent findings in prior research appear to be due to the criterion confounding of the Restraint Scale. Implications for the measurement of restraint are discussed.

Adolescent↗
PubMed1997

Comparison of sensitivity and specificity of tilt protocols with and without isoproterenol in children with unexplained syncope.

Head-up tilt testing with or without isoproterenol is extensively used in the evaluation of patients with unexplained syncope. However, sensitivity and specificity of tilt protocols with and without isoproterenol have not been clarified in children, due to lack of age matched control subjects. This study was designed to assess and to compare the sensitivity and specificity of tilting alone and tilting in conjunction with isoproterenol. Thirty children with unexplained syncope (group I) and 15 age-matched control subjects (control group I) underwent successive 60 degrees head-up tilts for 10 minutes during infusions of 0.02, 0.04, and 0.06 microgram/kg/min of isoproterenol, after a baseline tilt to 60 degrees for 25 minutes. Also, 35 children (group II) with unexplained syncope and 15 healthy control subjects (control group II) were evaluated by head-up tilt to 60 degrees for 45 minutes without an infusion of isoproterenol. In response to tilt protocol with graded isoproterenol, 23 (76.6%) of the patients in group I and 2 of the 15 (13.3%) control subjects developed syncope. Accordingly, the sensitivity of tilt testing with isoproterenol was 76.6%, and its specificity was 86.7%. Tilt testing without isoproterenol was positive in 17 (48.5%) of the patients in group II but in only 1 of the 15 (6.6%) control subjects. Thus, sensitivity and specificity of tilt testing without isoproterenol were 48.5% and 93.4%, respectively. The mean heart rate and systolic blood pressure decreased significantly (P < 0.001) in all tilt positive patients during syncope. In conclusion, the head-up tilt test is a valuable diagnostic test in the evaluation of children with unexplained syncope, and isoproterenol is likely to increase the sensitivity of the test without decreasing its specificity.

Adrenergic beta-Agonists↗
PubMed1995

Double-chambered right ventricle: experience with 52 cases.

The presence of anomalous muscle bundles may produce a pressure gradient between the inflow and outflow portions of the right ventricle, thus resulting in double-chambered right ventricle bearing troublesome clinically in its diagnosis. The aim of the present study was to review the diagnostic criteria. Fifty-two patients with a double-chambered right ventricle were seen during an 8-year period. They ranged in age at the catheterization from 4 months to 17 years (mean 7.5 +/- 4.4 years). Diagnosis was confirmed in 51 patients at cardiac catheterization and in other one on operation. The majority of the patients had associated cardiac anomalies: there were 33 ventricular septal defect (63%), 21 pulmonary valve stenosis (40%), nine atrial septal defect (17%), and four double-outlet right ventricle. The electrocardiograms revealed upright T waves alone in right precordial leads suggesting right ventricular hypertrophy in 33% of the patients. At cardiac catheterization, there was a pressure gradient of 20-160 mmHg between the right ventricular inflow and outflow portions. Forty patients have had surgery and four have undergone balloon pulmonary valvuloplasty. Surgical treatment was planned for two patients and other six had no indication for treatment.

Adolescent↗
PubMed1994

Left ventricular structure and function by echocardiography in childhood swimmers.

The purpose of this study was to determine the differences in the left ventricular dimensions, mass index and function in school-aged swimmers by echocardiography. The study group consisted of 82 swimmers who participated in a systematic swimming training for at least six months, and the control group consisted of 41 sedentary children of similar age, sex and weight. In the study group, left ventricular dimensions and wall thicknesses, aortic root and left atrium diameters, and left ventricle mass index were significantly greater than the normal children (p < 0.05). However, there was no difference in the left ventricular systolic function (ejection fraction, shortening fraction) or in the left ventricular filling characteristics (p > 0.05). In conclusion, in childhood swimmers there was a significant increase in left ventricular dimensions, wall thicknesses and mass index, but no differences in the systolic function and filling characteristics of the left ventricle. Thus, information on endurance training participation is necessary to interpret quantitative echocardiographic data.

Adolescent↗
PubMed1994

Partial anomalous pulmonary venous return. Evaluation of 51 cases.

Partial anomalous pulmonary venous return (PAPVR) is a congenital anomaly in which one or more, but not all, of the pulmonary veins are connected to a systemic vein or to the right atrium directly. Its incidence is higher in autopsy series than in clinical series. We report 51 cases of PAPVR diagnosed by cardiac catheterization and evaluated from the aspects of age, sex, type and associated anomalies and diseases.

Adolescent↗
PubMed1993

Causes of syncope in children: a prospective study.

We prospectively evaluated 80 patients with syncope, between January 1991 and January 1992 to determine the causes of syncope in children. There were 35 male and 45 female patients, whose mean age was 10.5 years. A single syncopal attack had occurred in 30 patients and multiple attacks in 50. A cardiovascular cause was established in 22 (27.5%) patients and a noncardiovascular cause in 36 (45%). The cause remained unknown in 22 patients (27.5%). Vasovagal syncope was the leading cause of syncope in these patients with an incidence of 32.5%. These findings suggest that every patient who has even one syncopal attack should be promptly investigated since the underlying cause could be a life-threatening one.

Adolescent↗
PubMed1992

Fixed subaortic stenosis in childhood. Medical and surgical course in 90 patients.

This study evaluated diagnostic criteria, clinical observations, surgical indications and complications in 90 cases of fixed subvalvular aortic stenosis. Echocardiography, catheter angiography and surgical findings indicated that 60 (66.6%) patients had subvalvular membranous stenosis, 20 (22.2%) patients had fibromuscular stenosis, 4 (4.4%) patients had membranous and fibromuscular stenosis, and 6 (6.6%) had a tunnel-type obstruction. Forty-two patients had additional cardiac anomalies, such as PDA, valvular aortic stenosis and VSD. Fifty patients were treated surgically. Thirty-six patients were evaluated by two-dimensional and Doppler echocardiography at post-surgical intervals ranging from 7 days to 11 years (mean 3.6 years). There were pathological echo findings in 12 patients. The prognosis of this anomaly depends upon early diagnosis and treatment. The results of this study support the importance of the two-dimensional and Doppler echocardiography in early diagnosis and follow-up of the surgical results in treatment of this anomaly.

Adolescent↗
PubMed1991

Endomyocardial biopsy in children. Usefulness in various myocardial disorders.

Endomyocardial biopsy studies in adults have demonstrated the usefulness of this method. It is possible that studies will be more productive in determining the etiology and clinical status in patients with clinically diagnosed myocardial diseases. A prospective study conducted over 16 months included 17 children, aged 14 months to 18 years, with the diagnosis of dilated, restrictive cardiomyopathy and myocarditis. In 16 patients right, and in 1 patient left heart endomyocardial biopsies were performed. The specimens were evaluated by light and electron microscopy. There were no serious complications after the procedure. In 1 of 17 children histology showed no myocardial tissue. Electron microscopy evaluations were currently available in 9 patients. Endomyocardial biopsy findings were found to be diagnostic in 41.2%, helpful in 29.4% and of no help in 29.4% of patients. In conclusion, endomyocardial biopsy technique is highly sensitive in children with myocardial disorders. In future it will be the major diagnostic tool for invasive but safe detection of myocardial disease.

Adolescent↗
PubMed1991

Congenital absence of pulmonary valve leaflets with intact ventricular septum in a neonate.

Symptomatic infants with congenital absence of pulmonary valve leaflets suffer primarily from respiratory insufficiency caused by bronchial compression by the dilated pulmonary arteries, and have a high mortality rate. We report the successful treatment of absent pulmonary valve syndrome with intact ventricular septum in a neonate. The treatment consisted of resection of the pulmonary artery aneurysm and enlargement of the pulmonary annulus.

Echocardiography↗
PubMed1990

Cardiomyopathies in children. Clinical, epidemiological and prognostic evaluation.

In this article, the clinical and epidemiological characteristics of 137 children with cardiomyopathy admitted to the Hacettepe Pediatric Cardiology Unit were studied and the prognosis was evaluated after a follow-up period of 24 +/- 5 months. It was found that the highest proportion of patients were residents of Ankara, followed by the Northern and the Central Anatolian regions, and consanguinity between their parents was more common than the proportion for Turkey as a whole. Most of the patients had dilated cardiomyopathy (78.9%) and the age at which symptoms appeared varied according to the type of cardiomyopathy. A high proportion of patients came to the hospital with complaints of dyspnea and a decrease in effort capacity. The most common findings on the physical examination were hepatomegaly and tachycardia. Electrocardiographic and echocardiographic evaluations were made for all patients and cardiac catheterization and endomyocardial biopsy were performed when necessary. The outcome was as follows: 34.5% improved, 45.7% remained stable, 9.5% deteriorated and 10.3% died.

Adolescent↗
PubMed1990

Pseudocoarctation of the aorta.

In this report 5 patients between the ages of 5-14 years admitted to the Department of Pediatric Cardiology, Hacettepe University, and diagnosed as having pseudocoarctation of the aorta are presented. The clinical and angiographic findings of this rare abnormality of childhood are discussed, the importance of differential diagnosis of this entity from coarctation of the aorta is emphasized, and the literature reviewed.

Adolescent↗