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Biomedical subjects

J Whitfield

Publications and source records attributed to J Whitfield.

45 records · Page 3Linked to original sources
PubMed1991

Cellular ras gene activity is required for full neoplastic transformation by polyomavirus.

To investigate the role of ras gene activity in cellular transformation by polyomavirus, murine C3H10T1/2 cells were rendered ras deficient by transfection with an antisense ras gene construct. Ras deficiency resulted in a partial suppression of the polyomavirus-induced transformed phenotype. The production of viral middle T antigen and its association with pp60c-src, increased membrane-associated protein kinase C activity, and morphological transformation were unaffected by the downregulation of c-ras gene expression. On the other hand, stimulated proliferation, focus formation on confluent monolayers of normal cells, and colony formation in soft agar were all greatly reduced in cells containing reduced p21ras levels. It is concluded that ras gene activity is needed for full cell transformation by polyomavirus.

Animals↗
PubMed1985

Association of low systolic and diastolic blood pressure with significant patent ductus arteriosus in the very low birth weight infant.

The systolic, diastolic, and pulse pressures of 34 infants weighing less than 1200 g, who required mechanical ventilation for hyaline membrane disease, were prospectively evaluated in the first week of life and related to the magnitude of ductal shunting. Seventeen infants developed a large patent ductus arteriosus (PDA) corresponding to significant left-to-right ductal shunting and requiring surgical ligation. By the second day of life these patients with large PDAs had significantly lower mean systolic and diastolic BPs than the non-PDA infants. There were no significant differences in pulse pressures between groups. Both systolic and diastolic BPs promptly returned to control values after ligation. A mean diastolic BP less than 28 mm Hg on the third day of life was significantly associated with a PDA in 93% of patients.

Blood Pressure↗
PubMed1984

The decreasing incidence of pneumothorax and improving survival of infants with congenital diaphragmatic hernia.

In the 6-year period between 1977 and 1982 inclusive, 75 newborn infants with congenital diaphragmatic hernia of Bochdelek underwent corrective surgery during the first 24 hours of life. A total of 40 infants (53%) survived. Beginning in January 1980, a standardized approach to care including early use of mechanical ventilation and paralysis with pancuronium as well as dopamine use prior to any Priscoline infusion, was instituted. To determine whether these approaches improved outcome, term infants without malformations from the years 1977 to 1979 were compared with a similar group treated after institution of standardized care between 1980 and 1982 inclusive. The infants were comparable in all respects, but survival improved from 45% to 82% between the two periods (P less than 0.03). There was an associated decrease in the incidence of pneumothorax (45% in first period; 14% in second period) paralleled by a concomitant increase in pancuronium use (18% and 85%, respectively). Although factors responsible for the improved survival are multifactorial these data indicate the detrimental effect of pneumothorax on outcome and the beneficial effect of a standardized approach to care using conventional intensive care techniques.

Critical Care↗
PubMed1983

Acquired subglottic stenosis in the very-low-birth-weight infant.

In the six-year period from 1975 through 1980, acquired subglottic stenosis was recognized in eight patients during the first year of life who survived intubated mechanical ventilation as newborn infants. Seven of eight cases occurred in infants who weighed less than 1,500 g at birth. This complication was not seen in the first three years of the review, when only nasotracheal intubation was practiced. In the second three years, orotracheal intubation was the predominant practice. Seven infants required tracheostomy and the outcome was poor: none has undergone decannulation and three have died. Recognition of this disorder as a cause of inability to extubate the very-low-birth-weight infant is stressed.

Child, Preschool↗
PubMed1982

Surgical and medical experience with 734 premature infants with patient ductus arteriosus.

During the past 5 years, patent ductus arteriosus (PDA) presented in 734 preterm infants (less than 2.5 kg and 37 weeks gestation) of 2,532 admissions (29%). The ductus presented with murmur, bounding pulses, and often congestive heart failure. Medical treatment consisted of the following: fluid restriction, furosemide, respiratory support, and rarely digoxin. The patients who were unresponsive to medical treatment had surgical ligation (306 of 734 or 42%). The patients who had ductal ligation were smaller, i .e., 82% of the surgical patients weighed less than 1.5 kg as compared to 38% of the medical patients. Of those patients weighing less than 1.5 kg, the surgical and medical groups were compared and the following observations made: The incidence of respiratory distress syndrome was greater in the surgical group (86% or 216 of 252 patients versus 69% or 111 of 161 medical patients, p less than 0.001) and the long-term survival was better (89% or 224 of 252 surgical patients versus 77% or 124 of 161 medical patients, p less than 0.005). In addition, the average duration of intubation was shorter in this surgical subgroup (8.9 versus 13.6 days). Significant left atrial enlargement and echocardiographic left atrial/aortic (LA/Ao) ratios of greater than 1.5:1 occurred in 58% or 171 of 290 surgical patients versus 32% or 59 of 190 medical patients (p less than 0.001). During the first 3 years of this study (medical treatment averaged 5 days), the duration of intubation in the surgical patients averaged 15.2 days; by comparison, in the last 2 years of this study (medical treatment averaged 1 to 2 days), the duration of intubation was 6.5 days (p less than 0.001). Necrotizing enterocolitis (NEC) occurred in 11% or 46 of 428 medical patients versus 0.3% (one of 305 patients) in the ligated group postoperatively (p less than 0.001). Late deaths were related to lung disease, central nervous system problems, NEC, and so on. From this study, it was determined that ligation of a significant PDA is associated with (1) zero surgical risk, (2) a reduced incidence of NEC, (3) reduced duration of intubation, especially with early ligation, and (4) improvement in late survival. Thus the surgical approach is our treatment of choice for a refractory PDA.

Age Factors↗