Biomedical subjects

T Oney

Publications and source records attributed to T Oney.

28 records · Page 2Linked to original sources

PubMed1982

[The value of a single determination of serum uric acid concentration in the early diagnosis of hypertensive disorders in pregnancy (author's transl)].

In 200 healthy, normotensive nulliparous women, a single determination of serum uric acid concentration was done between weeks 28-32 of gestation in order to identify a possible increased risk of developing hypertensive complications. If serum concentrations higher than 3.6 mg/dl were considered as increased ("positive test"), women who developed toxaemia of late pregnancy (proteinuric hypertension), had a significantly elevated mean serum uric acid concentration already at the beginning of the third trimester (p less than 0.01). The incidence of toxaemia and hypertensive disease without proteinuria was significantly higher in the group of women with an elevated uric acid value (p less than 0.001). Only 9% of pregnant women with a "negative test" ultimately developed a mild form of a hypertensive complication. Conversely, 74% of the patients with a "positive test" remained normotensive. Thus, the predictive value of a "positive test" is low (26%) and that of a "negative test" relatively high (91%).

Adolescent↗

PubMed1981

Decrease of vascular angiotensin sensitivity by L-dopa during human pregnancy.

In 27 pregnant subjects (21 treated women and six control subjects), the effect of L-dopa (500 to 1,000 mg orally) on vascular sensitivity to angiotensin II amide (Hypertensin, Ciba) was examined in 16 of these women, 1,000 mg of L-dopa resulted in a significant decrease in vascular responsiveness to angiotensin, i.e., an increase in angiotensin pressor dose from 16.9 +/- 5.0 to 19.6 +/- 4.5 ng . kg-1 . min-1 (mean +/- SD). In women with an initially low angiotensin pressor dose, the changes were more pronounced. In six control subjects, in whom two angiotensin infusion tests were performed consecutively without additional administration of L-dopa, an increase in vasopressor response to angiotensin was demonstrated. Possible causes for the L-dopa-induced decrease in angiotensin sensitivity are discussed: an inhibition of sympathetic nervous activity, a directly lowered total peripheral resistance, a natriuresis and diuresis, and an altered dopaminergic activity in the hypothalamus. It is hypothesized that long-term treatment with L-dopa or bromocriptine might not only decrease angiotensin sensitivity but also elevated pregnancy-induced hypertension.

Angiotensin Amide↗

PubMed1981

Effect of postural change on plasma renin and aldosterone concentrations in third-trimester pregnancy.

Plasma renin activity and aldosterone concentration were determined radioimmunologically after 30 minutes in the left lateral position and after an additional 30 minutes of supine recumbency in 26 normotensive nulliparous women between 28 and 32 weeks' gestation. Plasma renin activity decreased slightly but significantly in the supine position (P less than .05). A distinct increase of plasma aldosterone was observed in 14 of the 26 subjects. The following speculation has been drawn from these results: the fetal renin-angiotensin system is activated by decreased uteroplacental perfusion in the supine position, possibly followed by a diminution of blood flow to the fetal kidney, perhaps via hypoxia. Subsequently, aldosterone may also be secreted by the fetus at an increased rate. In contrast to the high molecular weight renin, aldosterone passes the placental barrier and appears in the maternal circulation.

Adult↗

PubMed1979

[Methods for the early recognition of gestosis].

The frequency of the severe forms of gestosis (preeclampsia) may be reduced by early recognition of this disease. By predicting hypertensive disorders of pregnancy, maternal and infantile perinatal mortality rates are expected to be lowered. The supine pressor test ("roll-over test") is recommended as an appropriate and simple method for routine screening during primigravid pregnancy. This test is rarely false-negative (2--9%; Bonn 3%), but a high percentage of false-positive results has been found in patients studied in Bonn. The angiotensin sensitivity test shows less false-positive pressor responses, but it is not practical for routine use either as infusion test nor as bolus test. The rate of false-negative results is sufficiently low in both methods. The routine determination of uric acid concentration in serum seems to be of no great value for predicting pregnancy-induced hypertension, compared with the roll-over test or with the angiotensin sensitivity test; however, it gives an additional information (a) in pregnancy women with questionable gestosis, and (b) in the differential diagnosis of pregnancy-induced versus pre-existing essential hypertension.

Angiotensin II↗

PubMed1979

Renin activity and concentrations of angiotensin I and II in amniotic fluid of normal and Rh-sensitized pregnancies.

Renin activity and the concentrations of angiotensin I and angiotensin II in amniotic fluid of second- and third-trimester pregnancies were determined by radioimmunoassay. Between the 28th and 38th wk of gestation, the mean renin activity in the amniotic fluid was higher than during early pregnancy (before the 18th wk of gestation). Both renin activity and the concentrations of angiotensin I and II were increased on some cases of Rh-incompatibility. One to two weeks after the administration of betamethasone to the mother with threatened premature delivery, the intra-amniotic renin--angiotensin system was slightly suppressed. In urine samples of newborns, angiotensin concentrations were in the same range as those found in the amniotic fluid; renin activity was very low or undetectable in the urine of male neonates (1--7 days of age). Thus, angiotensin II in the amniotic fluid may be derived both from fetal urine and/or as the product of enzymatic reactions in the amniotic sac; the latter is dependent not only on the presence of renin and converting enzyme but also on the local renin substrate (angiotensinogen) concentration.

Adult↗

PubMed1979

[New aspects of the pathophysiology of gestosis/pre-eclampsia (author's transl)].

An increased pressor responsiveness is consistently found in nulliparous patients with gestosis. The following mechanisms may be able to influence arterial reactivity: sodium balance, factors of the kallikrein-bradykinin and the renin-angiotensin systems, an imbalance between vasoconstrictive and vasodilatatory prostaglandins, the sympathetic nervous system, and possibly prolactin, too. A mechanism which is involved in the regulation of uteroplacental blood flow seems to be important in the etiology of gestosis. The immunological changes found in patients with gestosis are insufficient to support the concept of a primary immunopathogenesis. The usefulness of the supine pressor ("roll-over") test, of the angiotensin sensitivity test and serum uric acid determination in predicting hypertensive disorders of pregnancy is evaluated. The supine pressor test is recommended as an appropriate and practical method for routine screening in nulliparous pregnant women.

Angiotensin II↗

PubMedDate not supplied

Histochemical evaluation of placental angiotensinase A in pre-eclampsia: enzyme activity in villous trophoblast indicates an enhanced likelihood of gestational proteinuric hypertension.

The aim of this study was to examine whether differences in placental angiotensinase A (glutamyl aminopeptidase, EC 3.4.11.7) activities occurred in hypertensive complications of pregnancy compared with uncomplicated pregnancies. Biochemical and semiquantitative histochemical methods were used and compared for their applicability. Angiotensinase A activity was detected using L-alpha glutamyl-4-methoxy-2-naphthylamide (alpha-Glu-MNA) as substrate and Fast Blue B salt for simultaneous azo-coupling in cryostat sections of placental tissue samples from 32 patients with pre-eclampsia, 11 patients with pregnancy-induced hypertension and 44 participants with uncomplicated pregnancies. The graduated intensity of reaction product in the villous trophoblast and in fetal blood vessels was evaluated semiquantitatively in a double-blind study by light microscopy (semiquantitative score method). Score levels were related to relative frequencies of hypertensive disorders (proportional odds model) and correlated to the severity of gestational hypertension (Spearman's rank correlation). After detection of enzyme activity, the same tissue samples were homogenized and used for kinetic fluorometric measurements under the same substrate and buffer conditions as in enzyme histochemistry. Enhanced villous trophoblastic angiotensinase A activity was significantly associated with an increased frequency of pre-eclampsia in pregnant women (cumulative odds ratio x 0(1) 6.37; P < 0.001) and showed significant correlations with the severity of gestational hypertensive disorders, represented by systolic (r = 0.31; P < 0.05) and diastolic (r = 0.34; P < 0.05 blood pressure and by concomitant proteinuria (r = 044; P < 0.01). Histochemical evaluation of fetal blood vessels and biochemical measurements revealed no statistically significant results. In conclusion this study demonstrates for the first time that increased villous trophoblastic angiotensinase A activity indicates an increased likelihood of the presence of pre-eclampsia and the severity of hypertensive disorders in pregnancy.

Adult↗

PubMedDate not supplied

[Treatment of severe hypertension in pregnancy].

Treatment of severe hypertension in pregnancy, particularly in preeclampsia and eclampsia, is a great challenge to the obstetrician and requires prompt and expert management. Application of antihypertensive agents is limited during pregnancy because of possible side effects, particularly impairment of the fetal state. The following survey present a detailed discussion on the substances suitable for treating hypertensive emergencies in pregnancy and their side effects. Despite restricted therapeutic possibilities, safe and successful treatment of severe hypertension during pregnancy can best be performed with dihydralazine and diazoxide, which achieve their effect by reducing the peripheral vascular resistance. If the blood pressure cannot be adequately reduced with these substances, treatment can be continued with sodium nitroprusside. A critical discussion is presented in this connection on drugs such as clonidine and reserpine, which reduce pressure largely by central mechanisms and should no longer be applied in pregnant patients because of serious disadvantages. Consideration is also given to the special clinical problems associated with pheochromocytomas, and a concluding discussion deals with the perspectives of antihypertensive therapy in pregnancy.

Antihypertensive Agents↗

PubMedDate not supplied

[Liver diseases complicating pregnancy].

Liver disease in pregnancy represents a broad spectrum of disorders. Most of the common forms of acute and chronic liver disease occur during pregnancy and often present special difficulties in diagnosis and management. In addition, there is a group of hepatic disorders unique to pregnancy, which also must be identified appropriately. Rapid institution of therapy is important in preventing the unfavorable perinatal outcome and maternal mortality. The changes in liver function related to gestation will be reviewed initially. The major forms of hepatic disease specifically associated to pregnancy will be then described and the obstetrical management as well as the therapeutic modalities proposed.

Adult↗

PubMedDate not supplied

[Recklinghausen disease and pregnancy].

Morbus Recklinghausen is an autosomal dominant disease with a high rate of new mutations. Progression of the skin lesions and the development of severe preeclampsia are the most important complications during gestation. In the following paper three cases with Recklinghausen's disease in pregnancy are reported and the consequence of the complications as well as the importance of genetic counseling are discussed.

Adult↗