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Biomedical subjects

M Zugaib

Publications and source records attributed to M Zugaib.

At least 55 records · Page 3Linked to original sources
PubMed1990

Amniotic fluid lysozyme activity in fetal distress.

Lysozyme activity was measured in amniotic fluid samples from 90 pregnant women with gestational age ranging from 30 to 41 weeks. Twenty-nine samples were from high-risk subjects with different pathologies and signs of fetal distress. The control group consisted of 20 normal and 41 pathological pregnant women, whose disorders included Rh isoimmunization, diabetes, systemic arterial hypertension and pre-eclampsia without signs of fetal distress. Amniotic fluid lysozyme levels in normal controls were similar to those detected in abnormal pregnant women without signs of fetal distress (means = 156.0 vs 131.8 micrograms/ml for 34-37 weeks of gestation), with a tendency toward higher values as pregnancy progressed to term (means = 182.1 vs 155.4 micrograms/ml for 38-41 weeks of gestation). Lysozyme levels were significantly lower in high-risk pregnant women with signs of fetal distress, regardless of neonate birth weight, than in subjects showing no such signs (means = 40.3 and means = 25.4 micrograms/ml at 34-37 and 38-41 weeks of gestation, respectively). These data support the possibility of using amniotic fluid lysozyme activity levels as an indicator of fetal distress.

Amniotic Fluid↗
PubMed1990

[Prenatal diagnosis of congenital heart diseases and cardiac arrhythmias by Doppler echocardiography].

PURPOSE: To detect in prenatal life fetal arrhythmia and congenital heart disease. We performed fetal echocardiography following classical indications according to the literature. PATIENTS AND METHODS: Two-dimensional echocardiography associated with M-mode and Doppler was performed in 200 patients according to the indications: maternal diabetes, fetal arrhythmia, maternal congenital heart disease, previous fetus with cardiac defect, intrauterine growth retardation, nonimmune fetal hydrops, rubeola, isoimmunization, fetal malformation by ultrasound, polyhydramnios, gemelarity, oligohydramnios, maternal ingestion of drugs, lupus and others. RESULTS: Structural abnormalities of the heart were found in 6 cases and associated with bradiarrhythmia in 5 cases (total of 5.5%). Fetal arrhythmias without cardiac malformation were found in 35 cases (17.5%) and premature atrial contractions were the most frequent. CONCLUSION: The findings in this study indicate that it is possible the accurate definition of the cardiac anatomy and function. We have emphasized the method trying to spread it, objecting to improve assistance to the fetus and newborn with arrhythmias and/or congenital heart disease.

Arrhythmias, Cardiac↗
PubMed1985

Abruptio placentae following snake bite.

A case in which, besides the clinical complications that commonly follow snake biting, abruptio placentae occurred is reported here. None of the factors that are frequently associated with abruptio placentae were present. The laboratory tests performed showed that renal function was impaired and that a dramatic hypercoagulability was present. The relationship of the latter to the abruptio placentae is discussed.

Abruptio Placentae↗
PubMed1981

Nitroprusside-induced hemodynamic alterations in normotensive and hypertensive pregnant sheep.

It has been suggested that sodium nitroprusside, a potent vasodilator, be used in the management of an acute hypertensive crisis during pregnancy. The present study was designed to evaluate the hemodynamic effects of this agent in the same group of chronically instrumented, unanesthetized pregnant sheep during two experimental periods: (a) normotension with intact kidneys, and (b) one-kidney hypertension. The results demonstrate that (1) nitroprusside is a potent vasodilator which lowers mean arterial pressure; (2) nitroprusside-induced tachycardia was greater in the hypertensive animal; (3) uterine blood flow decreased with the development of hypertension; (4) the hypertensive-induced reduction in uterine blood flow was increased by the infusion of nitroprusside.

Animals↗
PubMed1981

Hemodynamic responses of the pelvic vascular bed to vasoactive stimuli in pregnant sheep.

The responses of the common internal iliac artery and middle uterine artery of the pregnant horn to continuous infusions of graded doses of norepinephrine, epinephrine, dopamine, isoxsuprine, angiotensin and nitroprusside were investigated in chronically instrumental pregnant ewes. Norepinephrine progressively decreased the blood flow and increased the resistance in both vessels but the changes were more marked in the middle uterine artery. Isoxsuprine and epinephrine had an insignificant effect on the common internal iliac artery blood flow, but decreased that of the middle uterine artery. Nitroprusside decrease the flow in both vessels proportionately. Angiotensin in doses less than 0.16 micrograms/kg/min increased the flow in both arteries to the same extent, but higher doses decreased both flows. It is concluded that in the chronically instrumented pregnant ewe, the responses of contiguous vascular beds to different vasoactive agents may differ depending on the nature of the stimulus.

Angiotensin II↗
PubMed1980

Mechanisms of beat-to-beat variability in the heart rate of the neonatal lamb. I. Influence of the autonomic nervous system.

The contributions of the intrinsic, beta-adrenergic, and cholinergic systems to the mechanisms of beat-to-beat variability of the heart rate were investigated in chronically instrumented, unanesthetized newborn lambs from the first week to the eighth week of neonatal life. During this period of neonatal growth, the resting heart rate decreased spontaneously every week; the decrease was not related to alterations in the sympathetic and parasympathetic tones but rather to changes in the intrinsic mechanisms of heart rate control. Despite the weekly decrease in the resting heart rate of the neonatal lamb, the long and short-term beat-to-beat variabilities did not change significantly. This finding suggests an absence of a significant influence of the intrinsic mechanisms of heart rate control on the genesis of beat-to-beat variability. The results obtained with the various modes of adrenergic and cholinergic blockades and stimulation seem to indicate that the autonomic nervous system contributes significantly to the appearance of beat-to-beat variability. However, the influences of the adrenergic and cholinergic systems differ from week to week of neonatal growth and the patterns of changes are not the same for the long-term and short-term variabilities. The implication of these studies in terms of physiologic and hemodynamic significance of beat-to-beat variability in heart rate is discussed.

Aging↗
PubMed1980

Mechanisms of beat-to-beat variability in the heart rate of the neonatal lamb. II. Effects of hypoxia.

The effects of acute hypoxia on the resting arterial pressure as well as on heart rate and its beat-to-beat variability were studied in chronically instrumented, unanesthetized newborn lambs at 2 to 8 weeks of neonatal life. Lung ventilation with a gas mixture containing 10% oxygen and 3% carbon dioxide decreased arterial blood PO2 by about 50% in all animals regardless of age without significantly altering blood pH and PCO2. This degree of hypoxia produced a mild pressor response, accompanied by a significant tachycardia; the pattern of these changes, however, differed somewhat according to neonatal growth. The impact of hypoxia on beat-to-beat variability of the neonatal heart rate also varied with age. When the lambs were 2 to 3 weeks old, both the long- and short-term variabilities decreased progressively during hypoxia and the decrement reached a maximum at 10 minutes of oxygen deprivation. As the lambs became older, however, there was some initial and transient increase in the long- and short-term variabilities in the early period of hypoxia but thereafter the changes were inconsistent. The significance of these observations is discussed in terms of our knowledge of the pathophysiologic alterations in the cardiovascular system produced by acute hypoxia.

Aging↗
PubMed1980

Morphologic and histochemical evidence for the occurrence of collagenolysis and for the role of neutrophilic polymorphonuclear leukocytes during cervical dilation.

Biopsy specimens of nonpregnant and intrapartum human cervices were studied by electron microscopy, and by the Picrosirius-polarization method which is a specific procedure for the detection of collagen fibers in tissue sections. The results obtained demonstrate a marked reduction of collagen fibers in the intrapartum material as compared to the samples of nonpregnant cervices. Evidence that indicated the presence of a widespread collagenolysis in the intrapartum biopsy specimens was obtained by both optical and electron microscopy, thus suggesting that this might be the main cause of the changes in the cervix that permit it to dilate during parturition. The study of the neutrophilic polymorphonuclear leukocytes in the intrapartum biopsy specimens strongly suggested that these cells participate in this process.

Cervix Uteri↗
PubMed1980

Hemodynamic effects of isoxsuprine and terbutaline in pregnant and nonpregnant sheep.

Nonpregnant and pregnant sheep at 110 to 140 days' gestation were chronically instrumented for measurement of mean arterial pressure, heart rate, cardiac output, common internal iliac artery blood flow, and middle uterine artery blood flow. Systemic and regional vascular resistances were calculated from pressure/flow data. Either isoxsuprine, 10 microgram/kg/min, or terbutaline, 0.40 microgram/kg/min, was infused continuously for a period of one hour. The above-mentioned parameters were monitored during control, infusion, and postinfusion periods. The findings show that: (a) isoxsuprine had greater effects on the mean arterial pressure, heart rate, and cardiac output than did terbutaline; (b) both agents had minimal effects on the common internal iliac artery blood flow of pregnant ewes, but isoxsuprine decreased the middle uterine artery blood flow significantly; and (c) with isoxsuprine, a marked vasodilatation occurred in the common internal iliac vascular bed of nonpregnant ewes, in contrast to the insignificant changes in the pregnant ewes. The conclusions drawn were that: (1) the more pronounced effects of isoxsuprine are most probably related to a greater beta 1 stimulation; (2) contiguous regional vascular beds respond differently to pharmacologic stimuli; and (3) the state of a given vascular bed during the resting state determines its response to vasoactive agents.

Animals↗
PubMed1980

Vascular reactivity to angiotensin II in the normotensive and hypertensive pregnant ewe.

The circulatory responses to progressively increasing doses of angiotensin II were studied in the same group of chronically instrumented unanesthetized pregnant sheep during three consecutive periods: a) normotensive with intact kidneys; b) normotensive with unilateral nephrectomy; and c) one-kidney hypertension. The results show that 1) the pressor response to a given dose of angiotensin was significantly greater in the normotensive than in the hypertensive condition; 2) uterine blood flow decreased markedly with the development of hypertension; 3) uterine circulatory response to angiotensin depended on the dosage; the response was less the the hypertensive than in the normotensive condition; 4) renal blood flow decreased and renal vascular resistance increased during angiotensin infusion, but the response was less in the hypertensive than in the normotensive condition; the response of the renal circulation decreased with increasing doses of angiotensin. These observations suggest a generalized vascular refractoriness to exogenous angiotensin II in the pregnant ewe with experimental renal hypertension.

Angiotensin II↗
PubMed1979

Effect of dopamine on hypotension induced by spinal anesthesia.

Chronically instrumented, near-term pregnant sheep were subjected to autonomic blockade with spinal anesthesia. Systemic arterial pressure, heart rate, and uterine blood flow decreased and uterine vascular resistance increased during the spinal blockade. Infusion of dopamine during the spinal hypotension corrected the disturbed circulatory parameters. These data provide evidence that: (1) the peripheral circulation of the near-term pregnant sheep is as sensitive as that of pregnant women to autonomic blockade, (2) the sensitivity is probably related to factors other than the changes in venous pressure in areas below the pelvis, and (3) dopamine represents a useful agent in the management of spinal hypotension.

Anesthesia, Spinal↗
PubMed1979

Circulatory effects of endotoxin on unanesthetized sheep and the response to dopamine.

The cardiovascular effects of endotoxin in the unanesthetized chronically instrumented sheep were investigated. The observations were extended to include the response to intravenous infusions of dopamine to the same sheep at the height of endotoxin action. When the cardiovascular effects of endotoxin in the unanesthetized and anesthetized sheep were compared, there were distinct differences. Unanesthetized sheep tolerated considerably greater dosages of endotoxin. In anesthetized sheep, the compensatory stimulation of the sympathoadrenal system seems to have been blunted and all of the circulatory parameters deteriorate rapidly, ending in death within three hours. In the absence of anesthesia, there was clear evidence of a compensatory sympathoadrenal stimulation, as reflected by the return of most of the circulatory parameters to normal values, and furthermore, the sheep recovered from the effects of endotoxin. The exact mechanism by which anesthesia altered the response of the sheep to endotoxin was not clear. Depression of the baroreceptor and neurohumoral compensatory mechanisms was suggested. The present data indicated that dopamine was a useful agent in correcting the cardiovascular changes brought about by endotoxin.

Anesthesia↗
PubMed1978

Control of the uteroplacental circulation in health and disease.

The various neurohumoral and intrinsic factors that control the uteroplacental hemodynamics in health and disease and in responses to physiologic and pharmacologic stimuli have been reviewed. The following conclusions may be derived: We still need improvement in our methodology of monitoring uterine blood flow. The present methods, which have some reliability, are not easily applicable to human subjects and even in animals their use presents problems of accuracy and sensitivity with which the investigator must become familiar. The marked and progressive increase in uterine blood flow that occurs during pregnancy is caused by complex factors, some of which are hormonal and hemodynamic in nature. The increased vascularity of the pregnant uterus and the opening of the arterioles during the process of formation of the intervillous space are important factors that facilitate the increase in uterine blood flow. The increment seems to be totally derived from the increment in the cardiac output that occurs during pregnancy. There seems to be no redistribution among the regional blood flows of the body. In the anesthetized condition the blood flow to the uterus depends largely on the perfusing pressure; the critical closing pressure seems to be around the 40 mm Hg level. This linear flow-pressure relationship does not, however, apply to the unanesthetized condition. A rise or fall in the perfusing pressure in the conscious state may be accompanied by an increase or decrease in the uterine blood flow, depending on the underlying mechanisms. Factors that lead to alpha-adrenergic stimulation produce an increase in uterine vascular resistance and a decrease in flow, irrespective of the status of the perfusing pressure. beta-adrenergic stimulation may increase uterine blood flow either through their vasodilating action or through their myometrial relaxing effects. Hypertensive diseases are most often accompanied by a decrease in uterine blood flow, whereas hypoxic states may decrease the flow even though the arterial pressure may not change significantly. It is extremely risky to extrapolate from information obtained in the anesthetized animal to the unanesthetized, conscious animal. Likewise, data obtained from normotensive conditions may not hold true for the hypertensive or hypotensive states. This is of particular relevance when one is dealing with the effects of pharmacologic agents that act on the cardiovascular system. Uterine contractions, whether induced through spontaneous or oxytocin-induced labor, produce a decrease in uterine blood flow.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenergic beta-Agonists↗
PubMedDate not supplied

Fetal idiopathic ventricular tachycardia with nonimmune hydrops: benign course.

A case of idiopathic ventricular tachycardia of left ventricular origin in a hydropic fetus is presented. The accuracy of fetal echocardiography for diagnosing this type of arrhythmia is emphasized, as is its importance in determining appropriate postnatal treatment which in this case resulted in an unusually benign course.

Adult↗