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Biomedical subjects

R M Nelson

Publications and source records attributed to R M Nelson.

At least 19 recordsLinked to original sources
PubMed1979

An evaluation of a continuous tissue pH monitor in the fetal and neonatal goat.

The validity of continuous tissue pH measurements was established in the fetal and neonatal goat model. Simultaneous determinations of tissue, arterial, and venous pH were done during alterations in acid-base status. A highly significant correlation was found between tissue and blood pH levels (r = 0.89, p less than 0.001). These data confirm the accuracy of the tissue pH instrumentation in predicting core blood pH status and support the potential usefulness of the instrumentation in perinatal medicine for continuous fetal acid-base monitoring.

Animals↗
PubMed1979

Bilateral internal iliac artery ligation in cervical pregnancy: conservation of reproductive function.

Like other forms of ectopic gestation, cervical pregnancy is a serious complication with potentially life-threatening consequences. Excessive bleeding almost invariably follows an attempt to evacuate this rare ectopic pregnancy. In most reported cases, hysterectomy has been required to control the severe hemorrhage. This paper reports for the first time the successful conservative management of cervical pregnancy in two patients by bilateral internal iliac artery ligation alone. Early recognition of the cervical pregnancy and prompt internal iliac artery ligation are stressed.

Adolescent↗
PubMed1979

Intrahepatic cholestasis associated with parenteral nutrition in premature infants.

Sixty-two premature infants less than 2,000 gm birth weight received parenteral nutrition (PN) during periods of respiratory distress with feeding intolerance. Intrahepatic cholestasis (direct bilirubin greater than or equal to 1.5 mg/dl) associated with PN developed in 14 or 23% of these infants. The mean time on PN to onset of cholestasis was 42 days, and the cholestasis persisted as long as the infants continued to receive PN. All five infants who had serial follow-up laboratory studies showed an eventual return of direct bilirubin levels to normal. The direct bilirubin level appeared to be the best clinically available test to monitor for the onset and to follow the resolution of this complication. The very low birth weight infants less than 1,000 gm appeared to be at an increased risk of developing cholestasis with an incidence of 50%. However, there was no correlation between the length of time PN was administered to onset of cholestasis and the gestational age or birth weight of the infants. These tiny premature infants also received PN for significantly longer periods of time, and the longer the infusions were administered the greater was the risk of cholestasis developing.

Age Factors↗
PubMed1979

Results of parathyroidectomy for autonomous hyperparathyroidism.

Autonomous hyperparathyroidism occurred in 15% of 152 patients maintained by long-term home dialysis during the past nine years. Twenty-two patients with elevated serum parathormone levels and progressive bone disease in the presence of normal serum phosphate and calcium levels were treated by subtotal parathyroidectomy. All had parathyroid hyperplasia. Eighteen of the 22 patients are presently alive and undergo dialysis. Symptoms of bone pain, pruritus, and muscle cramps had improved in three fourths of the patients. The serum parathormone level decreased from a preoperative average of 576 muLEq/mL to an average of 188 muLEq/mL postoperatively. All 18 patients, observed for six to 77 months, showed improvement in x-ray films of their bone disease. The autonomous hyperparathyroidism of end-stage renal disease is corrected by subtotal parathyroidectomy, and the effect is sustained.

Adult↗
PubMed1978

Solute permeability of the alveolar epithelium in alloxan edema in dogs.

The permeability of the alveolar epithelium following alloxan challenge was studied in dogs by determining transfer of radiolabeled solutes between alveolus and blood. Two days after injection of 131-Ialbumin into the blood, anesthetized dogs had the air space of part of one lung isolated by a balloon catheter lodged in a bronchus. We infused the atelectatis-isolated area with normal saline containing trace amounts of Blue Dextran, 125Ialbumin, and 57Co-cyanocobalamin; challenged six animals with intravenous alloxan, and six animals with alloxan added to the alveolar saline. During the pulmonary edema, 57Co-cyanocabalamin and 125I-albumin appeared in the blood and 131I-albumin entered the alveolar saline. The animals challenged by alveolar instillation showed a greater permeability change (P less than 0.05). The bidirectional transfer of macromolecules indicates that alloxan produces a change in the permeability of the alveolar epithelium, allowing diffusional exchange of macromolecules. Since alveolar flooding in hemodynamic edema does not show a similar change in the permeability of the epithelial lining, alveolar flooding in alloxan edema is not due solely to an effect on the endothelial membrane, but also to a direct effect on the epithelial membrane.

Alloxan↗
PubMed1977

Increased hypoxemia in neonates secondary to the use of continuous positive airway pressure.

Five neonates are presented who, while receiving continuous transpulmonary pressure, developed increased systemic arterial hypoxemia, which was relieved when this therapeutic modality was decreased or discontinued. Three of the five had chest radiographs consistent with hyaline membrane disease: the other two had atypical radiographs. None had evidence of air leaks. Levels of positive airway pressure utilized when the hypoxemia was noted ranged from 5 to 15 cm H2O. Calculated shunt fractions (Qs/Qt) improved from a mean of 73% to 37% when the continuous positive airway pressure was lowered. The site of shunting in these infants could have been in the lung or through anatomic extrapulmonary shunts. Improvement in total cardiac output may also have contributed to the improved oxygenation. This paradoxical effect of continuous transpulmonary pressure appears to be mediated through changes in the pulmonary vascular resistance brought about by the continuous transpulmonary pressure.

Cardiac Output↗
PubMed1977

Motor conduction of the anterior interosseous nerve.

Motor conduction examinations of the left anterior interosseous nerve were performed on 25 healthy women. The purposes of this study were to determine the optimal position for placement of the active recording electrode, and to report normal motor conduction values for the anterior interosseous nerve. The anterior interosseous nerve (branch of the median nerve) was stimulated proximal to the elbow and the evoked responses were recorded from three sites over the flexor pollicis longus. The optimal site for placement of the active recording electrode was over the lateral distal one-third of the anterior surface of the forearm at a point representing the distal 38% of the length of the forearm. A latency of 4.0 msec and an amplitude of 2.5 mv may serve as the limits of normal values for motor conduction of the anterior interosseous nerve and for action potentials of the flexor pollicis longus muscle, respectively.

Action Potentials↗