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Biomedical subjects

M Tobias

Publications and source records attributed to M Tobias.

At least 19 recordsLinked to original sources
PubMed1994

Monosomy 8q: prenatal diagnosis and autopsy findings.

The autopsy findings of a fetus with deletion of the long arm of chromosome 8 are described. Many of the features are similar to those of the tricho-rhino-phalangeal syndromes, types I and II, which are associated with deletions on chromosome 8q24. Other findings in this case, such as total absence of the corpus callosum and intestinal malrotation, have not been described in these syndromes. Genes involved in the development of the latter malformations may reside in adjacent regions on the long arm of chromosome 8. An elevated serum level of beta human chorionic gonadotropin (beta hCG) was found during pregnancy. This aberration should be included with other chromosomal disorders which may be detected by this test.

Abortion, Induced↗
PubMed1992

Prevalence of genital human papillomavirus infection in Wellington women.

OBJECTIVES: To determine prevalence of human papillomavirus (HPV) in Wellington women, to identify risk factors for HPV infection, to correlate presence of HPV with cervical cytology, and to identify characteristics of women infected with HPV but with normal cytology. DESIGN: Demographic, social, personal and clinical data were collected by a confidential self-administered coded questionnaire. The presence of DNA from HPV types 6/11, 16 + 18 and 31 + 33 in cervical scrapes was determined by dot-blot DNA hybridisation. All data were correlated with cervical cytology results. SETTING AND SUBJECTS: Two thousand and twenty one women attending family planning clinics in the Wellington region participated in the study. The mean age of participants was 26 years, 33.3% currently smoked, 72.3% used hormonal contraceptives, 31.4% were married, and 91.4% were of European origin. RESULTS: We found 10.9% of the study group infected with HPV. HPV types 16 and/or 18 predominated, being detected in 71.5% of HPV-positive women either alone or with other types. Of those infected 26.2% had multiple infections. Dysplasia (n = 87) or atypia (n = 84) were observed in 26.7% of infected women (n = 221) and 6.25% of uninfected women (n = 1792). Over 8% of women with normal smears were HPV positive, and types 16/18 were most common in these women. CONCLUSIONS: Women with cervical dysplasia or atypia were six times more likely to have HPV infection than other women. The main risk factor for HPV infection, particularly with types 16 and/or 18, was multiple (> 5) sexual partners in the last year independent of other variables. Multivariate analysis of data showed no independent association between HPV infection and ethnicity, educational background, smoking history, marital status, contraceptive use, age at first sexual intercourse, or number of lifetime sexual partners.

Adolescent↗
PubMed1991

Crossed renal ectopia. Case report.

Crossed renal ectopia is a relatively rare anomaly with non-specific manifestations, sometimes diagnosed incidentally. Eight cases are reported, the etiology, diagnostic approach and management of the urological complications are discussed.

Adolescent↗
PubMed1988

Viral respiratory tract infection and exacerbations of asthma in adult patients.

The role of viral respiratory tract infections in acute exacerbations of asthma was studied prospectively in 31 patients with atopic asthma aged 15-56 years. Patients recorded symptom scores for asthma and peak expiratory flow rate daily for 11 months. In addition, they reported for detailed clinical, functional, and virological study every four weeks and as soon as possible after the onset of worsening asthma or symptoms suggesting a respiratory tract infection. Thirty viral identifications were made, of which 18 (60%) were associated with an exacerbation of asthma. Viral respiratory tract infection was identified in 18 (10%) of the 178 exacerbations of asthma, and in 10 (36%) of the 28 severe exacerbations. The frequency of viral identifications in 16 non-asthmatic, control subjects during the same period was similar. It is concluded that viral respiratory tract infections may cause or be associated with exacerbations of asthma in adults, and that they are an important factor in severe exacerbations.

Acute Disease↗
PubMed1987

Measles immunity in children: the 1985 national immunisation survey.

In April 1985 a national immunisation survey was conducted, in the course of which blood samples were collected from approximately 3000 randomly selected children throughout the country. The study sample comprised approximately 1000 new school entrants, 1000 standard three pupils, and 1000 form four students. The sera were tested for morbilli antibody using an ELISA technique. Twenty-one percent of the five year olds lacked antibody, suggesting that an overall immunisation rate of about 80% is being achieved. Fourteen percent of the 15 year olds lacked antibody, suggesting that this rate of immunisation is partially interfering with the circulation of the wild virus. We conclude that a sizeable pool of susceptible adolescents is accumulating at a time when some wild virus activity still persists, and anticipate a shift in the peak age of measles infection from the 5-9 to the 10-15 age group. This unfortunate side effect of the national immunisation programme could be minimised by improving immunisation uptake in young childhood. Suggestions are made as to how this could be achieved.

Adolescent↗
PubMed1987

Radioisotopic flow scanning for portal blood flow and portal hypertension.

The use of a simple, noninvasive, isotope scanning technique for the determination of relative portal blood flow and detection of portal hypertension is described. Using this technique the presence of portal hypertension was demonstrated in seven of nine patients known to have elevated portal venous pressure. By contrast, esophageal varices were demonstrated in only five of these patients, illustrating the potential value of the method. Furthermore, this technique has been adapted to the study of portal blood flow in patients with myeloproliferative disorders with splenomegaly but without disturbances in hepatic architecture. Results demonstrate that the high relative splenic flow resulting from the presence of splenomegaly may in turn be associated with elevated relative portal blood flow and portal hypertension. The theoretic reasons for the development of flow-related portal hypertension and its relationship to splenic blood flow are discussed.

Blood Flow Velocity↗
PubMed1985

Technetium-99m glucoheptonate as a scanning agent in hepatocellular carcinoma.

Technetium-99m glucoheptonate (Tc-99m GH) is concentrated in pulmonary and cerebral tumors. The purpose of this study was to assess the uptake of this radionuclide by hepatocellular carcinoma. Its concentration by the primary tumor was compared with that in the non-neoplastic hepatic tissue in 31 patients who showed obvious defects on a colloid scan, and its uptake by pulmonary metastases was examined in six patients with x-ray evidence of this complication. In two patients, the uptake by the tumor was greater than, in six it was equal to, and in ten it was less than that in the non-neoplastic hepatic tissue. In the remaining 13 patients, there was no concentration at all in the tumor. In none of the six patients with multiple pulmonary metastases could uptake of Tc-99m GH by the metastases be demonstrated. It is concluded that Tc-99m GH is of limited value in the diagnosis of primary or metastatic hepatocellular carcinoma.

Adult↗
PubMed1985

The clinical value of scintigraphic brain scanning. Experience at the Hillbrow Hospital, Johannesburg, South Africa.

Patients were referred to the Department of Nuclear Medicine for brain scintigraphy to be screened for possible intracranial pathology. These referrals were made in order to reduce the heavy load on the transmission computerized tomography (TCT) facilities. Great clinical importance, therefore, has been attached to scintigraphic findings; this emphasizes the need for an accurate assessment of the predictive value of this procedure.

Adolescent↗
PubMed1983

Maternal and fetal plasma oxytocin levels during pregnancy and parturition in the sheep.

To assess fetal oxytocin release in relation to maternal oxytocin, serial paired maternal (femoral artery) and fetal (aorta) plasma oxytocin were determined by a specific and sensitive radioimmunoassay during pregnancy and parturition in the sheep. The maternal oxytocin level was 29.1 +/- 2.6 pg/ml (mean +/- SE) but was significantly lower than fetal oxytocin levels of 45.8 +/- 4.3 pg/ml (p less than 0.001). There was a significant correlation between paired maternal oxytocin and fetal oxytocin levels throughout late pregnancy (r = 0.2523, p less than 0.05). Maternal oxytocin levels calculated for every 5 days' gestation ranged from 15.8 +/- 2.7 to 32.7 +/- 5.6 pg/ml while the corresponding fetal oxytocin levels (21.6 +/- 3.5 to 62.5 +/- 21.6 pg/ml) were always higher (92 to 135 days) but not significantly different. However, at 136 to 142 days' gestation, fetal oxytocin levels (63.9 +/- 14.1 pg/ml) were significantly higher than maternal oxytocin levels (20.1 +/- 3.3 pg/ml) (p less than 0.01). Based on observations in two animals, fetal oxytocin levels appeared higher than maternal oxytocin levels at parturition with an increase a few days before labor. Our findings indicate that, in the sheep, fetal oxytocin levels were usually higher than but not significantly different from maternal oxytocin levels and that fetal oxytocin levels changed in relation to labor, suggestive of fetal release of oxytocin.

Animals↗
PubMed1982

The effects of diazoxide upon fetal and maternal hemodynamics and fetal brain function and metabolism.

The effects of maternal infusion of Diazoxide (D) were evaluated in two groups of experiments: Nine ewes and their five nonhypoxic fetuses; the remaining four fetuses were excluded because of the development of hypoxia prior to the study. D was directly administered intravenously (IV) to the six fetuses. In group 1 maternal and fetal observations were made at 0, 5, 15, 30, and 45 minutes. A 60-minute observation was also made for the maternal infusion studies. Maternal infusion of 5 mg/kg maternal weight significantly reduced maternal pH from the control value at 5 minutes. Maternal metabolic acidosis was indicated by concomitant significant reductions in base deficit (BD) and total bicarbonate (HCO3), both of which remained low for all subsequent time periods. Maternal lactic acid concentration also increased at 15 minutes, although not significantly. Maternal PO2 also fell significantly at 5 minutes, remaining significantly low for the remaining observations. A profound maternal hypotension was elicited at 5 minutes. All following observations for maternal blood pressure (MBP) were also significantly low. Fetal carotid arterial (FCA) pH declined significantly from the control period value at 15 minutes, remaining significantly low for the remaining observations. FCA O2% saturation (O2%) also witnessed a significant decline from baseline for all observations. FCA serum lactate level rose at 15 minutes; however, this was not deemed significant. No significant changes were seen in fetal brain metabolic rate of oxygen or glucose. Fetal electroencephalogram (EEG) revealed a definite hypoxic change in a majority of cases. In group 2, the effects of a direct fetal IV administration of 30 mg D (mean dose = 7.97 mg/kg fetal weight) were studied in six experiments. No significant changes in fetal acid base status or fetal blood pressure (FBP) were witnessed for the 45 minutes under scrutiny. Fetal heart rate (FHR) showed a short transient rise from baseline at 5 and 15 minutes, returning to normal thereafter. A slight significant decrease in O2% saturation and O2 content were seen only for the 5-minute observation. There were no significant changes of fetal brain function and metabolism observed following D administration to the fetus. The significant fetal hypoxia and acidosis witnessed through the maternal infusion but not in the direct fetal bolus administration were probably owing to profound maternal hypotension resulting in deterioration of uteroplacental perfusion and fetal "gas exchange."

Animals↗
PubMed1982

Effect of magnesium sulfate on maternal and fetal hemodynamics and fetal brain function and metabolism.

The hemodynamic effects, brain function, and metabolism of magnesium sulfate (MgSO4) were studied in seven fetal sheep experiments at 139 +/- 1.3 SE days of gestation. MgSO4 was intravenously infused to six gross-bred pregnant ewes at a rate of 4 gm/4 minutes as a loading dose, and 1.5 gm/60 minutes as a maintenance dose. There were no significant changes in maternal pH, PO2, O2 saturation, O2 content, HCO-3, glucose or lactate concentrations, or blood pressure at the end of the infusion. However, maternal heart rate decreased significantly from the mean baseline of 117 +/- 12.4 beats/minute at the end of the 60-minute infusion but recovered 30 minutes later. Uterine blood flow remained unchanged. Maternal Mg2+ levels rose significantly (P less than 0.005) at 60 minutes and remained elevated. No significant changes in fetal pH, PO2, PCO2, lactate, and Mg2+ concentration were noted during infusion. However, fetal heart rate increased significantly (P less than 0.025) at the end of infusion. Fetal hypotension was also noted at the end of the infusion (P less than 0.02). Cerebral blood flow did not change significantly throughout the experiment. However O2 consumption decreased temporarily at 15 and 30 minutes into infusion, which returned to baseline thereafter. Fetal glucose consumption and electroencephalogram remained unchanged throughout the experiment. Maternal infusion of MgSO4 does not exert any deleterious effects on the acid-base status of the mother or fetus. It increases the fetal heart rate and causes fetal hypotension, without any significant effects on the fetal brain function and metabolism.

Animals↗
PubMed1981

Effect of dexamethasone on the synthesis of dipalmitoyl phosphatidylcholine.

Glucocorticoids are known to enhance surfactant production by stimulating the formation of phosphatidylcholine. This study was performed to determine the effect of steroids on one of the pathways involved in the incorporation of palmitic acid into phosphatidylcholine--the 'deacylation-reacylation pathway'. Palmitoyl CoA synthetase, lysopalmitoyl cholineacyltransferase and phospholipase A2 were enhanced significantly as a result of direct administration of dexamethasone into 27-day fetal rabbits. Cycloheximide inhibited the steroid induced enhancement of activity. Immunologic studies demonstrated an accelerated rate of synthesis of palmitoyl CoA as a result of the dexamethasone treatment. The data suggest that steroids are capable of inducing enzymes of the 'deacylation-reacylation pathway' involved in palmitate incorporation into phosphatidylcholine thereby contributing to the acceleration of dipalmitoyl phosphatidylcholine biosynthesis.

1-Acylglycerophosphocholine O-Acyltransferase↗
PubMed1981

The effects of terbutaline on the acid base balance and circulation of chronically instrumented pregnant sheep.

Terbutaline is considered an effective beta agonist with beta 2 character, for the inhibiton of labor. Its safety was evaluated in twelve infusions of 1,500 micrograms over 30 min, to 8 'steady state' pregnant sheep of 110--134 days of gestation. Experimentation was performed at least 4 days postoperatively. Maternal (n = 12) and fetal (n = 7) arterial blood samples were drawn at 0, 10, 20, 30, 60- and 90 min from the start of the infusion. Uterine blood flow (UBF), blood pressure (BP), and heart rate (HR) were monitored continuously. Maternal pCO2, bicarbonate (HCO-3), and base excess (BE) decreased significantly during the infusion. Maternal pH, pO2, and O2% saturation of the hemoglobin (O2%) remained constant. Maternal hemoglobin (Hb) increased significantly at 10 min. A significant maternal hypotension and tachycardia followed the infusion. UBF decreased by 26% at the end of infusion, recovering by 60 min. Fetal pH, pCO2, Hb, O2%, BP, HR, HCO-3, BE, and CO2 content all remained stable for the duration of the experiment. Fetal arterial pO2 transiently increased at 10 min. No other significant fetal effects were observed.

Acid-Base Equilibrium↗