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Biomedical subjects

P L Lewis

Publications and source records attributed to P L Lewis.

17 recordsLinked to original sources
PubMed1990

Herbert screw fixation of osteochondral fractures about the knee.

Osteochondral fracture of the patella or femoral condyle may occur with patella dislocation. Accepted treatments of these fractures are excision or replacement. In this paper eight cases are described in which the Herbert Bone Screw system was used for fixation. Normal knee function was regained within 6 months and there were no reported recurrent dislocations. The advantages of this technique are that it is simple, there is little cartilage damage done during insertion, the screw is entirely buried and therefore does not interfere with the soft tissues, fixation is rigid enough to allow for the application of continuous passive motion to aid in cartilage repair, and re-operation for removal is not necessary.

Adolescent↗
PubMed1986

Metyrapone delays surfactant and antioxidant enzyme maturation in developing rat lung.

The surfactant system and the antioxidant enzyme system of the fetal lung have chronologically similar developmental patterns and both can be accelerated by the administration of exogenous glucocorticoids. To test whether the antioxidant enzyme system, like the surfactant system, is regulated, at least in part, by endogenous glucocorticoids, we injected pregnant rats for 3 days prior to delivery with metyrapone, an adrenal 11-beta hydroxylase inhibitor which crosses the placenta and blocks endogenous glucocorticoid synthesis, or saline. Metyrapone offspring had significantly decreased lung tissue disaturated phosphatidylcholine/total phospholipids (p less than 0.05) compared to controls at days 21 and 22 of gestation. Activities of the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase were similarly significantly reduced (p less than 0.01) in the lungs of metyrapone offspring at both gestational days studied. One day premature metyrapone pups demonstrated poorer survival than control pups from 25 min after delivery (44% survival versus 83%, p less than 0.05) to 90 min (6% survival versus 78%, p less than 0.01). These findings of delayed maturation of the surfactant and antioxidant enzyme systems following adrenal glucocorticoid blockade suggest that both systems are regulated, at least in part, by an endogenous glucocorticoid mechanism.

Animals↗
PubMed1985

Intrauterine growth-retarded rat pups show increased susceptibility to pulmonary O2 toxicity.

We used a nutritional deprivation model to produce intrauterine growth-retarded (IGR) rat pups (birth weight = approximately 75% of normal). The IGR newborns evidenced a marked reduction in tolerance to greater than 95% O2 exposure: 10-day survival = 10/47 (21%) versus 18/36 (50%) for control pups, and LT50 = 7.2 days versus 10 days for controls (p less than 0.01). Various lung parameters at birth and during O2 exposure were examined to try to define why prenatal undernutrition should compromise the survival of IGR rats in hyperoxia. We found decreased lung glutathione peroxidase and glucose-6-phosphate dehydrogenase activity (with normal superoxide dismutase and catalase levels) in the IGRs at birth; decreased lung disaturated phosphatidylcholine content (even more markedly decreased in 1-day premature pups); and decreased lung surface area/body weight. These factors and other features of newborn IGRs reported in the literature may help to explain how prenatal undernutrition compromises postnatal tolerance to prolonged high-O2 exposure.

Animals↗
PubMed1985

Dexamethasone stimulation of fetal rat lung antioxidant enzyme activity in parallel with surfactant stimulation.

It has recently been determined that fetal lung antioxidant enzyme activity markedly increases late in gestation. A test was made of whether this normal late-in-gestation change in O2-protective enzymes would be responsive to the maturing effect of hormonal (glucocorticoid) treatment. Pregnant rats received 0.2 mg/kg of dexamethasone (or saline) at 48 and 24 hours prior to delivery of their fetuses on gestational days 19, 20, 21, and 22 (newborn). Lung disaturated phosphatidylcholine showed an expected response to prenatal dexamethasone exposure with significant elevations of surfactant lipid at gestational days 20 and 21. A similar effect of prenatal dexamethasone treatment on the lung antioxidant defensive system was found. Superoxide dismutase, catalase, and glutathione peroxidase--enzymes protective against hyperoxia-induced lung injury--showed an accelerated pattern of maturation with significant increases in the dexamethasone-treated fetal lungs compared with control fetal lung enzyme levels at gestational days 20 and 21. The results suggest that prenatal dexamethasone treatment may have dual benefits when used in impending premature deliveries--that is, it may stimulate maturation of both the surfactant system and also the antioxidant enzyme system, and this maturation can help protect the premature newborn's lungs from the toxic complications of hyperoxic therapy that may be required because of immaturity.

Animals↗
PubMed1977

Effects of crush and devascularizing injuries to the proximal ureter. An experimental study.

Crush and devascularizing injuries were performed on proximal canine ureters. The pathogenesis of the reaction to these injuries was evaluated by using microbiologic, physiologic, radiologic, biophysical, histologic, and anatomic techniques. The results indicated that within 12 weeks after crush injuries lasting up to 60 min, renal function fully returned and radiologic demonstration of the crush area resolved, even through other radiologic and pathologic changes persisted in hte crushed ureters. The pathophsiologic results of devascularizing injuries that did not resolve spontaneously tended to progress more rapidly and case more serious renal impairment than any of the crush injuries. Devascularizing injuries that resolved tended to be benign in their effect.

Animals↗
PubMedDate not supplied

Gastric remnant cancer after Billroth II procedure.

Six cases of gastric remnant cancer that occurred many years after Billroth II gastrectomy and gastrojejunostomy for benign disease are reported. They are classified as intestinal type and gastric type on the basis of their morphologic appearance. Their cytologic and histologic features are tabulated along with a summary of the clinical histories. Emphasis is placed on the possible high risk for patients with Billroth II procedures of developing cancer 10 to 25 years after surgery. Endoscopic follow-up including cytologic study is essential to diagnose gastric remnant cancer in its early stage to secure a better prognosis.

Aged↗