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Biomedical subjects

G Cassady

Publications and source records attributed to G Cassady.

At least 55 records · Page 3Linked to original sources
PubMed1982

Ultrastructure of the lung after ventilation.

We looked at the ultrastructure of the lung of rabbits ventilated with air moistened with nebulized water ("nebulized group"), and humidified air ("humidified group") compared to a group of controls. Both groups of ventilated rabbits had plasmalemmal vesicles that were larger than in controls. They were fewer in number (P less than 0.001) and less well defined. Early degenerative changes were noted in 6 of 9 rabbits in the nebulized group and 6 of 9 rabbits in the humidified group, while none of the rabbits in the control group were similarly affected. Interstitial oedema of varying severity was seen in 6/9 rabbits from each of the ventilated groups.

Animals↗
PubMed1981

Postnatal physiologic hypercholemia in both premature and full-term infants.

Previous studies have shown that bile salt concentrations in human blood taken from the placenta at birth of term infants are in the range found in adults. A 125I-radioimmunoassay procedure and capillary gas liquid chromatography-mass spectrometry have been used in this investigation to measure serum bile salt concentrations in premature and normal term infants. It was found that the serum bile salt concentration in samples taken at birth in premature infants were also similar to that of adults. In the week after birth the serum bile salt concentration rose four- to sevenfold in each of the infant groups. The increase was independent of gestational age and the "health" of the child. A similar increase was observed in term infants. Thus, hypercholemia is physiologic in newborn infants. In conjunction with other abnormalities of the enterohepatic circulation of bile salts there are profound implications in the newborn for the metabolism and excretion of those endogenous and exogenous substances that are dependent on the secretion of bile salt by the liver. In addition, speculations concerning the role of parenteral nutrition in the induction of cholestasis in premature infants should be made with caution.

Age Factors↗
PubMed1980

Papillary muscle necrosis in a neonatal autopsy population: incidence and associated clinical manifestations.

Papillary muscle necrosis was found in 24 of 84 neonates without congenital heart disease who died and were autopsied during a 17-month study period. The lesion was most prevalent in infants greater than or equal to 3,000 gm birth weight (59%), but papillary muscle necrosis was also noted in 25% of the infants of medium birth weight (1,500 to 2,999 gm) and in 19% of the very low-birth-weight infants (less than 1,500 gm). Papillary muscle necrosis in the highest birth-weight group correlated with five-minute Apgar scores of 6 or less, meconium aspiration syndrome, seizures, congestive heart failure, increased cardiothoracic ratio (greater than or equal to 0.60), and ischemic changes on electrocardiogram. In the medium- and very low-birth-weight groups, however, patients with papillary muscle necrosis could seldom be differentiated clinically from their birth-weight peers without the lesion, even in retrospect.

Autopsy↗
PubMed1980

Effects of gas temperature and particulate water on rabbit lungs during ventilation.

Anesthetized young rabbits were ventilated for 6 hr at 20 cm H2O peak airway pressure using air nebulized with water at 22 degrees C (cold nebulized group, n = 11), at 36 degrees C (warm nebulized group, n = 11) and humidified air at 36 degrees C (warm humidified group, n = 10). Their biochemical status during ventilation and pulmonary morphology at autopsy were compared to those of ten control rabbits. Both nebulized groups had particulate water in the inspired air and water of condensation in the endotracheal tube. The rabbits ventilated with warm humidified air and the control group breathing spontaneously maintained their blood pressure and pHa within physiologic range. Rabbits ventilated with air nebulized with water at 22 and 36 degrees C had a significant decline in mean blood pressure (96 mm Hg leads to 61 mm Hg in cold nebulized and 91 mm Hg leads to 61 mm Hg in warm nebulized) and mean pHa (7.43 leads to 7.23 in cold nebulized and 7.42 leads to 7.31 in warm nebulized). All rabbits in the control and warm humidified groups survived the study whereas 9 of 22 in the nebulized groups died before completion of study (P < 0.005). Morphometric analysis revealed a significant increase in the mean vascular wall thickness in both nebulized groups of rabbits when compared to that in the control and warm humidified groups (P < 0.05). The cold nebulized group also had significantly less air space and correspondingly more interstitial thickness and intraalveolar edema (P < 0.05) compared to control and warm humidified groups. These findings of pulmonary parenchymal damage in rabbits ventilated with air containing particulate water and the greater degree of both physiologic and anatomic change evident in the cold nebulized animals suggest that particulate water and low inspired air temperature may contribute to the genesis of pulmonary damage during intermittent positive pressure ventilation.

Animals↗
PubMed1980

Effects of intermittent positive-pressure ventilation on lungs of normal rabbits.

We ventilated 10 healthy young rabbits with warm moist air at 20 cm H2O peak airway pressure and compared their pulmonary histology to that of 10 controls. The histological changes were analysed using the Leitz Texture Analysis System. Four hundred high-power fields (240 micrometers X 240 micrometers) were scanned from each section and the mean proportions of air space, interstitium and oedema determined. Calculated bicarbonate decreased significantly in both groups (P < 0.05); this was accompanied by a modest decrease in pHa in the ventilated group. The PaO2 and PaCO2 were maintained within the normal range. The blood pressure decreased in both groups. Seven of 10 ventilated rabbits had interstitial widening while only 1 of 10 controls had a similar lesion (chi 2 = 5.21, P = < 0.05). The area occupied by interstitium ranged from 26 to 46% (mean 37.6%) in controls and 18 to 81% (mean 45.4%) in ventilated rabbits. There was a lack of correlation between clinical and histopathological findings. While 6 of 10 ventilated rabbits had intra-alveolar oedema and a decrease in air space to less than 50% of total area, none developed hypoxaemia. Two of these 6 rabbits also had pHa less than 7.35 by the end of the study, yet all were clinically stable. These data indicate that intermittent partial-pressure ventilation with warm moist air may result in pulmonary parenchymal damage within 6 h in healthy rabbits.

Animals↗
PubMed1980

Regional neonatal transport: impact of an integrated community/center system.

In the face of increasing neonatal referrals from a large geographic region, community hospital resources was recruited and coordinated with regional center resources to facilitate "community-based" neonatal transport. All transport requests were first "triaged" by an attending neonatologist. Discriminant analysis was used to assess the impact of resource allocation decisions. Decisions regarding allocation of resources to an individual transport generally reflected geographic distance to be traveled, size of delivery service at referring hospital, and apparent degree of illness. Physicians participation in transports was reduced from 95% to 15% of the trips. The incorporation of community-based transport resources and nonphysician transport teams into a coordinated triage and transport process with existing center-based resources did not adversely affect neonatal survival. Capacity of the transport system was enhanced with these reallocations.

Alabama↗
PubMed1979

Transcutaneous oxygen (tcPO2) measurements as an aid to fluid therapy in necrotizing enterocolitis.

Impaired peripheral perfusion is a major problem in necrotizing enterocolitis with delayed recognition and definite documentation being primary factors. While blood pressure and other clinical measurements may improperly estimate the severity of the problem, changes in transcutaneous oxygen measurements and their relationship to arterial oxygen (the tcPO2/PaO2 ratio) potentially afford a sensitive measurement of peripheral perfusion. Experience in our unit confirms a close relationship between tcPO2/ and PaO2 being 0.97 +/- 0.04 (SE). Ten infants with birth weights of 640 to 1380 g, who subsequently developed necrotizing enterocolitis, had strikingly lower ratios initially (0.00, 0.00, 0.00, 0.17, 0.21, 0.43, 0.44, 0.48, and 0.56). Use of the tcPO2/PaO2 ratio to monitor fluid therapy was related to outcome, suggesting that this ratio is important in managing necrotizing enterocolitis.

Enterocolitis, Pseudomembranous↗
PubMed1978

Subcutaneous fat necrosis of the newborn.

Subcutaneous fat necrosis of the newborn (SFNN) developed in a 1-week-old black boy. His mother had received numerous medications for eclampsia. Birth was by Caesarean section and complicated by meconium aspiration. There were numerous nodules over the back, buttocks and extremities that yielded a caseous-like material. Microscopically, these nodules showed crystallization and necrosis of the fat. Hypoglycemia, pneumonia, oliguria, thrombocytopenia, seizures and urinary infection were associated with the cutaneous problem and led to a fatal outcome 2 weeks after birth.

Adult↗
PubMed1977

Amniotic fluid glucose in pregnancies complicated by diabetes.

Amniotic fluid glucose (AF glu) was studied in 92 pregnancies complicated by maternal diabetes. An inverse relation between AF glu and gestational age was found: [AF glu (mg. per diciliter) = 160.9 -- 3.51 (weeks gestation); r = -0.47]. A direct relation between AF glu and severity of maternal diabetes was observed: mean AF glu (mg. per deciliter) = 24.6 +/- S.D. 12.3 in Class A, 41.2 +/- 25.5 in Class AD and 57.5 +/- 36.5 in Classes B-D. A positive correlation of AF glu with osmolality was observed [AF Osm (mOsm. per kilogram) = 250.7 + 0.22 AF glu; r = +0.50], but this relation was remarkable inconsistent in individual patients. Neither individual nor serial AF glu levels were of any prognostic value in predicting fetal condition or perinatal outcome.

Amniocentesis↗
PubMed1977

Relation between arterial blood pressure and blood volume and effect of infused albumin in sick preterm infants.

The relation between directly measured arterial blood pressure and blood volume was studied in 61 sick preterm infants. Mean blood volume (derived from plasma volume [T1824 ten-minute albumin space] and hematocrit value) of 26 hypotensive infants (89.1 +/- 17.26 ml/kg) was not significantly different from that of 35 normotensive, but otherwise comparable, infants (91.4 +/- 14.57 ml/kg). There was no relation between arterial mean blood pressure and blood volume. Twenty-one infants with arterial mean blood pressure less than 30 mm Hg were given 1.0 g/kg of 10% salt-poor albumin. Significant increases in blood pressure occurred but were small in magnitude; more than one half of infants had arterial mean blood pressures persistently less than 30 mm Hg. Arterial/alveolar PO2 ratio decreased significantly with albumin infusion in six infants with hyaline membrane disease not receiving continuous distending-airway pressure, suggesting an association between infused albumin and impaired oxygen exchange.

Albumins↗
PubMed1976

Amniotic fluid osmolality in pregnancies complicated by diabetes.

Amniotic fluid osmolality (AF Osm) was studied in 247 patients whose pregnancies were complicated by maternal diabetes. Significant increases in mean AF Osm accompanied pre-existing fetal as well as subsequent perinatal death. Abnormal increases in AF Osm were associated with a significant increase in risk of perinatal compromise with cumulative morbidity and mortality rates of 54 per cent. These data suggest that serial evaluation of AF Osm enables detection of a "higher risk" group of diabetic pregnancies in which perinatal death is more than doubled.

Adolescent↗
PubMed1976

Neonatal pneumopericardium.

Six cases of pneumopericardium in neonates with hyaline membrane disease were observed during a six-month period. Five babies were receiving positive inspiratory or expiratory pressure or both. All but one had other extra-alveolar air collections. In three cases, sudden decrease in PaO2 was the only recorded sign that led to diagnosis. Pericardial aspiration was performed in four babies; one died and three either survived or died later of unrelated disease. One neonate was not treated and died of other causes. Treatment was delayed in the sixth infant; the pneumopericardium disappeared spontaneously but soon reappeared and contributed to a fatal outcome, although a drainage catheter was inserted. This experience and review of other authors' observations suggest that prompt drainage by catheter and continuous suction is indicated.

Drainage↗