Biomedical subjects
Publications and source records attributed to A Capponi.
Extracardiac and cardiac flow velocity waveforms were recorded in a severely growth-retarded fetus 1 day and a few hours before fetal death. At the first scan, the typical Doppler patterns of a growth-retarded fetus were found, but the brain-sparing effect was lost at the last examination and a huge tricuspid insufficiency was demonstrated.
OBJECTIVE: Our purpose was to evaluate the incidence and patterns of chromosomal abnormalities in fetuses with absent end-diastolic velocity in umbilical artery and to analyze maternal and fetal factors associated with abnormal karyotype. STUDY DESIGN: One hundred ninety-two fetuses of known karyotype with absent end-diastolic velocity in the umbilical artery at a gestational age > 20 weeks were considered. The following potential risk factors were analyzed in a multiple logistic regression model: maternal age, gravidity, parity, gestational age at diagnosis, presence of gestational hypertension and preeclampsia, presence of fetal malformations, different biometric measurements, head/abdominal circumference ratio, amniotic fluid volume, and several Doppler index values calculated from uterine arteries, fetal heart, and fetal peripheral arteries and veins. RESULTS: Sixteen cases had an abnormal karyotype. In two cases a triploidy was present, whereas the remaining 14 cases had autosomal aberrations. The risk factors statistically significantly and independently associated with the presence of an abnormal karyotype were maternal age > 35 years, gestational age at diagnosis < 27 weeks, presence of multiple malformations, and absence of gestational hypertension and preeclampsia. All the fetuses with an abnormal karyotype but one were correctly identified by at least one risk factor. CONCLUSIONS: An abnormal karyotype is present in 8.3% of fetuses with absent end-diastolic velocity in umbilical artery and is associated with maternal and fetal risk factors. The knowledge of these factors may be useful in the management of such fetuses.
The objective of this study was to evaluate whether Braxton-Hicks contractions induce changes in fetal heart rate variation in normal and growth-retarded fetuses. 110 uncomplicated singleton pregnancies were cross-sectionally studied as well as 16 pregnancies complicated by fetal growth retardation secondary to uteroplacental insufficiency. Fetal heart rate variability was analyzed by a commercially available computerized system (2CTG Hewlett Packard, Italy) 10 min before and 10 min after the Braxton-Hicks contraction. All the included fetal heart rate tracings fulfilled the following criteria: (1) presence of a single Braxton-Hicks contraction in the 20 min considered; (2) absence of fetal heart rate decelerations after the contraction, and (3) stable fetal heart rate behavioral pattern in the period analyzed. 82 tracings of normal fetuses were analyzed during an active fetal heart rate pattern (type B) and the remaining 28 during a quiet pattern (type A). In both patterns no significant differences in delta value, long-term irregularity, short-term variability and interval index were found before and after the contraction. All the tracings of growth-retarded fetuses were analyzed during the fetal heart rate pattern A. Short-term variation and interval index significantly decreased during the first 5 min after the contraction while no significant differences were found in the other indices investigated. The decrease in these indices was significantly more marked in those fetuses developing fetal distress within 7 days. In conclusion, Braxton-Hicks contractions induce a significant decrease of short-term variation and interval index only in growth-retarded fetuses. This can be useful in the early identification of fetal compromise in such fetuses.
In an effort to determine the factors influencing the abnormal ventricular filling patterns of fetuses of type I diabetic mothers, Doppler flow velocity waveforms were recorded from fetal atrioventricular valves in 37 pregnancies complicated by type I diabetes immediately before an elective cesarean section. The ratio between the peak velocities during early passive ventricular filling and active atrial filling was calculated at the level of both atrioventricular valves and related to different factors including ventricular chamber wall thickness, heart rate, umbilical vein hematocrit and time to peak velocities values obtained at the outflow tract. Multiple stepwise regression demonstrated that the interventricular wall thickness, heart rate and hematocrit values significantly and independently affected the ratios between early and active ventricular filling from mitral and tricuspid valves. As a consequence all these factors should be taken into account in the interpretation of atrioventricular Doppler indices.
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Reference limits for the PI from the umbilical, middle cerebral, and renal arteries were constructed using BPD, AC, FL, and transverse cerebellar diameter as independent variables and their efficacy tested in a population of SGA fetuses. Therefore, 153 normal fetuses and 90 SGA fetuses with established dates between 20 and 40 weeks of gestation were considered. Normal fetuses showed a linear negative relationship between the PI from all the vessels investigated and all the biometric parameters considered. Although the BPD related better with the PI from the umbilical artery (r = 0.646) and the renal artery (r = 0.765) and the transverse cerebellar diameter related better with middle cerebral artery PI values (r = 0.510), no evident differences in fitting were found among the variables tested. In SGA fetuses the nomograms on BPD, AC, and FL significantly underestimated PI values in all the vessels studied when compared to the nomograms based on gestational age, while a similar ability in identifying abnormal PI values was found for nomograms based on gestational age and transverse cerebellar diameter. These newly developed nomograms based on transverse cerebellar diameter may prove useful in the evaluation of Doppler indices of fetuses with uncertain gestational age.
Covalent dimerization of the adrenocorticotropin fragment ACTH11-24 increases its antagonistic potency on the ACTH-induced steroidogenesis in isolated bovine fasciculata/reticularis cells by 3 orders of magnitude when the C-termini are linked via a 10 A long spacer. This strong potentiation, probably mediated by cross-linking of the receptors, was shown to be dependent on the point of attachment of the monomeric fragment to the spacer, thus providing information about the position of the binding site in the hormonal segment and about the distance of the receptors on the cell surface.
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1. The morphology of the juxtaglomerular apparatus, plasma renin activity, plasma renin substrate and renal renin have been studied in rats after maximal stimulation by bilateral adrenalectomy and salt depletion, and also after blocking this stimulation by deoxycorticosterone and salt load. 2. After stimulation the juxtaglomerular apparatus showed a well-developed granular endoplasmic reticulum and a low secretory granule content. Plasma renin activity was markedly elevated and plasma renin substrate was low. After blockade numerous specific granules with crystalline structures were seen and the granular endoplasmic reticulum was less developed. Plasma renin activity was now low and plasma renin substrate elevated. 3. After prior acidification of the kidney extract a significant increase of renal renin was observed in both conditions but was greater in the second group at the time when large numbers of young granules containing crystalline material were seen. 4. Kidney slices from the adrenalectomized salt-depleted rats released more renin than control slices. Vincristine did not affect this release, but inhibited release from slices stimulated by isoprenaline.
The objective of this study was to investigate the effects in early gestation of retroplacental hematomas on Doppler indices measured in different fetal vascular districts and to relate these changes, if any, to the volume of hematoma and pregnancy outcome. Thirty-eight pregnancies complicated by bleeding and ultrasonographic findings of retroplacental hematomas were considered for this study. Menstrual age ranged between 9 and 14 weeks. Blood flow velocity waveforms were measured in the umbilical artery, descending aorta, middle cerebral artery, and inferior vena cava. The pulsatility index in arterial vessels was calculated as well as the percentage reverse flow in the inferior vena cava. The values obtained were compared to previously constructed reference limits. No significant differences were found for any of the Doppler indices when the values obtained in pregnancies complicated by retroplacental hematomas were compared to the reference limits. Furthermore no significant relationships were found between the Doppler indices and either the size of hematoma or pregnancy outcome. In conclusion, retroplacental hematoma does not induce hemodynamic effects in the fetal circulation before 14 weeks, menstrual age. These data do not support the use of Doppler ultrasonography in early gestation for pregnancies complicated by bleeding and retroplacental hematomas.
The oral calcium load test, originally proposed for evaluating the intestinal calcium absorption and the renal calcium leak triggers some endocrine and metabolic responses addressed to correct the "calcemic error" induced by the load. Besides the increased plasma calcium there are: plasma PTH drop, increment in the urinary calcium excretion and in the threshold of tubular phosphate reabsorption. These responses have been measured and reciprocally correlated in 9 young adults at different times after the oral calcium load. The responses can be assessed with high precision in clinical practice and are in agreement with the known physiological models. The oral calcium load test is proposed as a tool for studying in the osteopenic population in the individual's capacity of correcting the calcemic error induced by the load.
The purpose of this study was to verify if a decreased inhibition of PTH secretion (abnormal suppressibility) in response to physiological increment of plasma calcium is present in patients with osteoporosis. The plasma concentration curve of intact PTH 1-84 following an oral calcium load (Pak) has been calculated in a selected population of 38 osteopenic patients (16 males and 22 females) and in a control group of 9 young healthy adults. All the patients included in this study a) had no past or present diseases and medications of potential influence on calcium homeostasis, b) showed a maximal calcemic response to the oral calcium load equal to that of the control group. PTH suppressibility was significantly smaller in the osteoporotic patients (-42% in males and -32% in females) than in the control group (-76%). This abnormal suppressibility of PTH is independent on sex and, in the females, also on postmenopausal estrogen deficiency. These results support the hypothesis that osteoporosis is associated to an altered secretory response of parathyroid glands maybe due to reduced sensitivity of the parathyroid cells to extracellular calcium.