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Biomedical subjects

M D Cunningham

Publications and source records attributed to M D Cunningham.

At least 55 records · Page 3Linked to original sources
PubMed1984

Maternal transfer and retention of supplemental selenium in neonatal calves.

Selenium concentrations in blood serum of heifer calves from dams fed 0, 1, or 5 mg supplemental selenium daily during the dry period were compared. Dry cows were fed corn silage top dressed with a soybean meal mineral mix containing the desired amount of selenium. At birth, calves were assigned to one of six treatments in a 3 x 2 factorial arrangement. Calf treatments were 0, 1 (at birth), or 2 (at birth and 14 days of age) injections of selenium/vitamin E with feeding of starter commencing at 14 or 28 days of age. Dosage per injection was .078 mg selenium and 5.4 IU vitamin E per kilogram body weight. Selenium concentrations of blood serum of cows at parturition were 14, 32, and 58 ppb for cows fed 0, 1, and 5 mg selenium per day. Amount of selenium fed to cows affected selenium concentrations in blood serum of their calves with those from cows fed 5 mg selenium having the greatest concentrations. Calves from cows fed no supplemental selenium showed increased selenium in serum at day 28 and 42 when given one or two injections of selenium. Two injections, however, were necessary to elicit a response in calves from cows fed 1 mg per day. Selenium in blood serum of calves from cows fed 5 mg per day was not elevated when calves were given one or two injections of selenium. Prepartum selenium supplementation of the dam elevated selenium of blood serum in the calf at birth.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1983

Surfactant dysfunction in diabetic offspring: inhibitors and fatty acid lecithin content.

We have previously demonstrated that the lungs of fetuses of alloxan-diabetic rabbits are functionally immature when compared with controls. In this study we have examined pulmonary lavage fluid from fetuses of diabetic and control does for the presence of a surfactant inhibitor, cholesterol content, and phosphatidylcholine (lecithin) fatty acid content. When lavage fluids from fetuses of control and diabetic does were mixed and examined on the surface balance, the measured surfactant content corresponded to the arithmetic average of the surfactant content of the individual fluids, thus ruling out the presence of an excess of a surfactant inhibitor. We were able to demonstrate inhibition of surfactant function when exogenous cholesterol was added to lavage samples, but cholesterol content of lavage fluid from fetuses of diabetic and control does was not significantly different. Finally, the fatty acid composition of surfactant phosphatidylcholine was not different between the two groups. These studies indicate that mechanisms other than the presence of a surfactant inhibitor or altered fatty acid composition must explain the functional immaturity seen in offspring of the diabetic pregnancy.

Animals↗
PubMed1983

Selenium/vitamin E: role in disease prevention and weight gain of neonatal calves.

A 3 X 2 factorial arrangement of treatments comparing 0, 1, or 2 injections of a selenium/vitamin E preparation and feeding of starter commencing at 14 or 28 days of age was used to examine effects of supplemental selenium/vitamin E on health and growth of neonatal calves. Dosage per injection was .078 mg selenium and 5.4 international units of vitamin E per kg body weight. Neither a single injection at birth nor two injections (birth and day 14) reduced incidence of respiratory diseases or improved weight gains in unstressed calves. Calves first offered starter at 14 days as compared with 28 days gained more weight in the 56 days. A single injection of selenium/vitamin E at birth increased selenium of blood serum at day 14 by 87%, and a second injection increased selenium of blood serum at day 28 an additional 10%. Selenium of blood serum of calves not given an injection decreased linearly from birth to day 56. Calves first fed starter at day 14 had lower concentrations of selenium of blood serum from day 28 to 42 than calves first offered starter at day 28. Glutathione peroxidase activity of erythrocytes was higher in calves receiving one or two injections of selenium/vitamin E than in control calves; however, a lag of 4 to 5 wk occurred between injections and elevation of glutathione peroxidase activity.

Animals↗
PubMed1982

Improved prediction of fetal lung maturity in diabetic pregnancies: a comparison of chromatographic methods.

Following planned termination of pregnancy, infants of diabetic mothers have shown a continued vulnerability to the respiratory distress syndrome (RDS), suggesting false positive results on fetal lung maturity testing. We studied the adequacy of the standard one-dimensional chromatographic lecithin/sphingomyelin (L/S) ratio for predicting RDS in 56 diabetic and 50 nondiabetic pregnancies. An exceptionally low incidence of RDS was noted for the study (0.95%) as well as for diabetic pregnancies alone (1.85%). The clinical results were further compared to a new method for determining L/S ratios and identifying other pulmonary phospholipids by two-dimensional chromatography. Values for two-dimensional L/S ratios were significantly lower from 36 through 38 weeks' gestation (P less than 0.01), suggesting improved accuracy and a lessened risk for false positive results in preterm deliveries. Positive identification of amniotic fluid phosphatidylglycerol (PG) was related to increasing L/S ratios (P = 0.001), but only 50% of nondiabetic and 16.7% of diabetic amniotic fluid samples contained PG when the L/S was 2:1 or greater (P = 0.02). The identification of PG serves to confirm fetal lung maturity, but the L/S ratio remains the best available indicator of fetal lung maturity for all high-risk pregnancies.

Chromatography↗
PubMed1982

Complications associated with digoxin therapy in low-birth weight infants.

Eighteen infants, each weighing less than 1,500 gm, were treated with low dose digoxin therapy for patent ductus arteriosus and signs of circulatory congestion. Nine of the 18 developed one or more signs of clinical deterioration felt to be related to digoxin therapy: eight infants experienced frequent episodes of bradycardia, six had cardiac arrhythmias, and six experienced feeding difficulties. All signs disappeared when digoxin therapy was discontinued. Digoxin, even in relatively low dosages, can have deleterious complications in seriously ill low-birth-weight infants. Alternatives to digoxin in this patient population should be considered before institution of digoxin therapy.

Arrhythmias, Cardiac↗
PubMed1980

Echocardiography in hypoxemic neonatal pulmonary disease.

Sixteen newborn infants with severe pulmonary parenchymal disease and profound hypoxemia were treated with mechanical ventilation, alkalinization, and intravenous tolazoline. Eight infants responded within two hours of initiation of tolazoline therapy with a rise in Pao2 by at least 100% of pretreatment values (mean = 188%, range = 103 to 427%). Eight infants showed little or no change in Pao2 with administration of tolazoline. Echocardiographic evaluation prior to therapy demonstrated marked elevation in both left (LPEP/LVET = 0.52 +/- 0.13) and right (RPEP/RVET = 0.56 +/- 0.08) ventricular systolic time intervals in the eight infants who subsequently responded to tolazoline. Systolic time intervals in nonresponders were within the normal range (LPEP/LVET = 0.37 +/- 0.03, RPEP/RVET = 0.33 +/- 0.04) and were not significantly different from those observed in a control group of 15 infants with pulmonary disease requiring mechanical ventilation but without hypoxemia. Following tolazoline therapy, systolic time intervals in all eight responders fell to normal values. Echocardiography can provide a safe, noninvasive method for identifying those infants with primary pulmonary disease and severe hypoxemia who could be expected to benefit from tolazoline therapy, thereby avoiding tolazoline side effects in infants for whom tolazoline therapy can be predicted to be of little benefit.

Echocardiography↗
PubMed1980

Impaired surfactant production in cretin lambs.

Midgestation ovine fetal thyroidectomy resulted in profound congenital hypothyroidism and severe respiratory distress at term. Amniotic fluid obtained at delivery revealed low lecithin: sphingomyelin (L:S) ratios in all animals with a predominantly acidic phosphatide pulmonary phospholipid profile. Surfactant was diminished in the lung effluent of cretins at birth as compared with normal lambs. The acidic phosphatides and low L:S ratios persisted in the pharyngeal aspirates of the cretin lambs following attempted air breathing and the onset of severe respiratory distress. Conversely, normal lambs released considerable surfactant at birth that contained nonacidic phosphatides dominated by dipalmitoyl lecithin and yielding strongly positive L:S ratios. Comparative histologic studies revealed poor alveolar differentiation in certain lambs and persistence of the midgestation canalicular stage of lung development.

Amniotic Fluid↗
PubMed1980

Umbilical vessel catheterization.

Umbilical vessel catheterization has become a commonly performed procedure in intensive care nurseries across the country. Catheterizing umbilical vessels can be a lifesaving step when newborn infant resuscitation is required. Moreover, considerable diagnostic and therapeutic advantages can be achieved for certain sick infants in observation or special care nurseries. The procedure requires careful patient selection and proper technical performance.

Catheterization↗
PubMed1978

Amniotic fluid phosphatidylglycerol in diabetic pregnancies.

Despite L/S ratios indicating fetal lung maturity, respiratory distress continues to occur more frequently in infants of diabetic mothers. Amniotic fluid pulmonary phospholipids were studied in an attempt to understand the occurrence of false-positive L/S ratios in preterm diabetic pregnancies. Qualitative chromatography assays of surfactant phosphatides revealed reduced or absent phosphatidylglycerol in diabetic amniotic fluid specimens between 34 and 37 weeks' gestation. Mean phosphatidylglycerol in 15 nondiabetic and 29 diabetic specimens was 16 and 4 per cent of total extracted pulmonary phospholipids (P less than 0.001). Non-insulin-dependent diabetic pregnancies had lowest mean per cent phosphatidylglycerol. Respiratory distress occurred in six infants of diabetic mothers delivered preterm with L/S ratios of 2:1 or greater; phosphatidylglycerol was absent in five. The inclusion of phosphatidylglycerol in amniotic fluid phospholipid assessment may be an adjunctive index for fetal lung maturation in diabetic pregnancies.

Amniotic Fluid↗
PubMed1977

Perinatal aspects of omphalocele and gastroschisis.

Forty-one infants treated for abdominal wall defects were studied retrospectively. Using established anatomic criteria the infants were identified as having either an omphalocele or gastroschisis. They were compared for maternal and infant characteristics to determine if distinct perinatal characteristics exist between the two groups. Gastroschisis patients had lower mean maternal age, were more likely to be first born, and to be of lower birth weight. Major malformations apart from those associated with the gastrointestinal tract and the anterior abdominal wall occurred 12 times more often in omphalocele patients. Ventral defects warrant a careful anatomical and clinical differentiation, and in the case of omphalocele, a thorough search for other anomalies.

Abnormalities, Multiple↗
PubMed1976

Transillumination of the skull in premature infants.

Transillumination of the skull in infants is a simple technique which can be used to detect several major abnormalities of the central nervous system. The usefulness of transillumination has been limited, however, by the lack of standard techniques for its performance and by the absence of normal values, especially in premature infants. In healthy premature infants, there is a progressive increase in transillumination with increasing gestational age over three sites--the anterior fontanelle, the frontotemporal fossa, and the parieto-occipital eminence.

Analysis of Variance↗