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Biomedical subjects

F Mimouni

Publications and source records attributed to F Mimouni.

At least 19 recordsLinked to original sources
PubMed1992

Progression of diabetic retinopathy in pregnancy: association with hypertension in pregnancy.

OBJECTIVE: To test the hypothesis that women with insulin-dependent diabetes and chronic or pregnancy-induced hypertensive disorders are at increased risk for developing retinopathic complications during pregnancy. STUDY DESIGN: One hundred fifty-four women with insulin-dependent diabetes were prospectively followed in an intensive program of diabetes in pregnancy. Ophthalmologic evaluations were obtained through pregnancy and at 6 to 12 weeks post partum, and findings were graded by a standard scale. Association of retinopathic progression with risk factors was tested with chi 2 and multiple logistic regression analysis. RESULTS: Fifty-one women had progression of retinopathy during pregnancy; postpartum regression was observed in 13 women. Changes in glycemic control early in pregnancy, chronic hypertension, and pregnancy-induced hypertension were significantly associated with progression of retinopathy. CONCLUSION: Women with insulin-dependent diabetes who have hypertensive disorders in pregnancy are at increased risk for progression of retinopathy.

Diabetes Mellitus, Type 1↗
PubMed1992

Neonatal hematocrit and maternal glycemic control in insulin-dependent diabetes.

We hypothesized that in infants of diabetic women neonatal hematocrit would correlate with third-trimester maternal glycemic control. Neonatal hematocrit correlated with the maternal total glycosylated hemoglobin level at delivery (r = 0.36; p less than 0.05) but not at 36 weeks of gestation in 32 mother-infant pairs. Improved maternal glycemic control during late gestation may decrease the incidence of neonatal polycythemia.

Blood Glucose↗
PubMed1992

Birth trauma in insulin-dependent diabetic pregnancies.

Infants of insulin-dependent diabetic mothers are considered to be at high risk for birth trauma, presumably due to macrosomia. With current management of diabetes in pregnancy, including strict glycemic control, the rate and the severity of macrosomia should be decreased. The frequent use of ultrasound to assess fetal growth and weight and the use of cesarean delivery in case of fetal macrosomia should further decrease the risk for birth trauma in these infants. We therefore undertook this study to test the null hypothesis that with current management, insulin-dependent diabetic mothers have a rate of birth trauma similar to that of infants of nondiabetic mothers (normal glucose challenge test at 28 weeks' gestation) matched for gestational age at birth, presence or absence of labor, delivery method (vaginal versus cesarean), and race. We studied 118 insulin-dependent diabetic mothers (White classes B-RT) and 354 control subjects (three matches for each insulin-dependent diabetic mother). The rate of birth trauma was 3.4% in insulin-dependent diabetic mothers, not significantly different from controls (2.5%). Logistic regression analysis in which birth trauma was the dependent variable and diabetes, race, presence or absence of labor, mode of delivery (vaginal versus cesarean), infant weight, and infant head circumference were independent variables revealed that only vaginal delivery was a significant risk factor for birth trauma in infants in both groups (p = 0.01). Most frequently observed birth traumas were brachial plexus injury, facial nerve injury, and cephalohematoma. Of the three infants with brachial plexus injury (insulin-dependent diabetic mothers, two; controls, one), two were delivered with use of midforceps.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Effect of chronic maternal dietary magnesium deficiency on placental calcium transport.

Metabolisms of calcium (Ca) and magnesium (Mg) are closely interrelated in the intestine, bone, and kidney. Interaction of Ca and Mg at the placental level, however, is not well defined. The occurrence of decreased bone mineral content and hypocalcemia in infants of hypomagnesemic mothers led us to test the hypothesis that chronic dietary maternal Mg deficiency decreases placental Ca transport. On day 10 of gestation, 20 Sprague-Dawley rats were randomized to a Mg-deficient diet (3.3 mg/day, n = 10) or to a control diet (70 mg/day, n = 10). On day 20 of gestation (term = 22 days), intact placentas were perfused in situ through the umbilical artery and perfusate was collected through the umbilical vein. Calcium 45 (45Ca) and chromium 51-EDTA (51Cr-EDTA) (a diffusional marker for placental membrane integrity) were injected to the dam and steady state maternofetal clearance (Kmf45Ca, microliter/min/g placenta) of both isotopes were calculated. There was no difference in the clearance of 45Ca and 51Cr in both groups (55 +/- 10 vs 57 +/- 16 and 3.2 +/- 0.4 vs 3.6 +/- 0.4, respectively, mean +/- SEM). We conclude that, in the rat, placental Ca transfer is unaffected by chronic maternal dietary Mg deficiency. We speculate that Ca and Mg cross the placenta by independent mechanisms.

Animals↗
PubMed1992

Low bone mineral content in summer-born compared with winter-born infants.

Possible seasonal differences in newborn bone mineral content (BMC) have not been studied. Adult studies show seasonal variations with lower BMC in winter versus summer. Assuming that BMC variations may relate in part to vitamin D status, we hypothesized that newborn BMC would be lower in winter than summer. BMC of one third distal radius was measured in 55 healthy term newborns using a single beam photon absorptiometer [coefficient of variation (CV) for phantom standard 2.1%]. Infants were enrolled during summer (July-September, 1988) and winter (January-March, 1989) for a longitudinal nutrition study. Contrary to our hypothesis, there was a 12% lower BMC in summer versus winter (mean +/- SD 75.94 +/- 17.42 vs. 86.55 +/- 17.54 mg/cm, respectively; p = 0.035). The difference remained significant after controlling for possible race and gender effects (p = 0.02). We conclude that BMC is lower in summer- compared with winter-born infants. Since any seasonal effects on fetal bone are presumably related to effects through the mother, we speculate that if maternal vitamin D status influences fetal bone mineralization, the effect (possible sunshine deprivation in winter) may operate especially in early pregnancy, thus resulting in lower BMC, evident at birth in summer.

Black People↗
PubMed1992

Osteoma cutis as a presenting sign of pseudohypoparathyroidism.

Four unrelated children with osteoma cutis and Albright hereditary osteodystrophy (pseudohypoparathyroidism and pseudopseudohypoparathyroidism) are described. All four patients were normocalcemic when they were first seen with cutaneous ossification. A diagnosis of Albright hereditary osteodystrophy was established on the basis of associated somatic features, radiographic abnormalities, and family history. Progression to pseudohypoparathyroidism was documented in two children who developed hypocalcemia at 2 and 3 years of age, respectively. Early recognition of the skin manifestations of this syndrome and careful follow-up are important to prevent the deleterious effects of hypocalcemia. Osteoma cutis is a common sign of Albright hereditary osteodystrophy in infancy and childhood, and its significance should not be overlooked, even in the normocalcemic patient.

Female↗
PubMed1991

Severe rickets in Lowe syndrome: treatment with continuous nasogastric infusion.

A boy with Lowe syndrome who manifested renal Fanconi syndrome by severe hypophosphatemic rickets, failure to thrive, and metabolic acidosis failed to improve with conventional bolus therapy of phosphate and bicarbonate. He was then placed on home continuous nasogastric infusion of phosphate and bicarbonate in addition to caloric supplementation. Rapid reversal of metabolic acidosis and hypophosphatemia was achieved. There was significant improvement in clinical and radiological signs of rickets and in bone mineral content. After 9 months therapy, his ponderal age improved dramatically from 7.5 to 29.5 months and his statural age from 16 to 26 months. We conclude that continuous nasogastric infusion of phosphorus and bicarbonate is a useful alternative mode of therapy in patients with renal Fanconi syndrome who are resistant to conventional bolus therapy.

Acidosis↗
PubMed1991

Effects of maternally administered epidermal growth factor on placental permeability.

Epidermal growth factor is a well-studied modulator of epithelial membrane structure and function. Mammalian placentas are a rich source of epidermal growth factor receptors, but the role of epidermal growth factor in placental pathophysiologic conditions is unclear. To determine whether epidermal growth factor could affect mechanisms of placental transfer, we used an in situ rat placental perfusion model. Fourteen Sprague-Dawley rats that were 20 days pregnant were randomized to epidermal growth factor or placebo during placental transport experiments. We chose ethylenediaminetetraacetate tagged with chromium 51 as a marker of placental permeability. Epidermal growth factor treatment led to a dramatic increase of maternofetal clearances of chromium 51-ethylenediaminetetraacetate. We conclude that maternally administered epidermal growth factor has a potent action on placental permeability.

Animals↗
PubMed1991

Umbilical cord ulceration and intestinal atresia: a new association?

In three fetuses, congenital intestinal atresia was associated with linear ulcerations of the umbilical cord. In two cases, hemorrhage was seen from the cord ulcer. Both fetuses required emergency cesarean section for fetal distress and were born anemic. The third fetus was mildly hydropic, attributed to hemorrhage, and was stillborn. The mechanism of the association could not be determined. These cases suggest a risk of prenatal umbilical cord hemorrhage in infants with intestinal atresia.

Adult↗
PubMed1991

A role for magnesium in neonatal parathyroid gland function?

Little is known of the factors regulating parathyroid function in the neonatal period. Twenty-seven term infants born after uncomplicated pregnancies, labors, and deliveries were studied to test the hypothesis that in normal newborns the amplitude of parathyroid hormone (PTH) response to decreasing serum ionized calcium (iCa) correlates with serum magnesium (Mg) concentrations. Serum iCa (ion selective electrode, Radiometer ICA 1), PTH (1-84 intact molecules, radioimmunoassay) and Mg (atomic absorption) were measured at birth (cord blood) and 24 hours of age. Repeated measures analysis of covariance showed decreasing serum iCa (p less than 0.01) and increasing serum Mg (p less than 0.01) and PTH (p less than 0.01) over time. The change in PTH over the first 24 hours was directly correlated with cord blood (r = 0.38, p less than 0.05) and 24-hr Mg concentrations (r = 0.53, p less than 0.01). We conclude that the ability of the parathyroid gland to respond to decreasing serum iCa after birth is directly related to Mg status. We speculate that neonatal hypomagnesemia may lead to a blunted PTH secretory response, thus contributing to early neonatal hypocalcemia.

Analysis of Variance↗
PubMed1991

A case-control study of hypocalcemia in high-risk neonates: racial, but no seasonal differences.

A role for vitamin D in the defense against falling serum calcium (Ca) concentrations following cord clamping has been suggested. Since race and season are known to affect vitamin D status, we theorized that black race and birth in winter are additional risk factors for neonatal hypocalcemia (NHC). We retrospectively studied 13,462 infants born at University Hospital (Cincinnati, OH) between January 1, 1984 and December 31, 1987. Serum Ca was measured at 24 hours of age routinely in infants with low birth weight (less than 2500 g), preterm delivery (less than 2500 g), preterm delivery (less than 37 weeks), neonatal asphyxia, and diabetic mothers. After exclusion of infants of diabetic mothers (to remove maternal diabetes as a major confounder) and infants with major congenital anomalies, 714 infants remained. In multiple regression analysis, low serum Ca values were significantly associated with low gestational age (p less than 0.01), low Apgar score (p less than 0.01), and white race (p less than 0.01) (R2 = 0.457). Season or month of birth was not significant. In pair-matched analysis controlling for factors other than season, season of birth did not affect serum Ca. In pair-matched analysis controlling for factors other than race, white race was once again a risk factor for hypocalcemia. Thus, low gestational age, low Apgar score, and white race, but not black race and delivery in winter, are risk factors for NHC. We speculate that in our climate and with the prevailing diet in pregnancy, vitamin D deficiency does not appear to play a role in NHC.(ABSTRACT TRUNCATED AT 250 WORDS)

Black or African American↗
PubMed1991

Effects of albumin on ionized calcium in vitro.

Human serum albumin is used to treat hypoproteinemia in neonates or used as a volume expander. We tested the hypothesis that the addition of human serum albumin to neonatal serum decreases the serum ionized calcium (iCa) concentration. Concentrated human serum albumin was added to 12 placental and cord serum samples to reach seven incremental concentrations from 0 to 20.0 g/L. Serum iCa concentration decreased significantly with the addition of serum albumin. From multiple regression analysis, the effect of albumin addition on serum iCa concentration had more marked effects at high baseline albumin or low baseline Ca concentrations. From this in vitro study, we speculate that fast infusion of albumin in human neonates has the potential for acutely lowering serum iCa concentration.

Blood Proteins↗