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Biomedical subjects

J W Thorp

Publications and source records attributed to J W Thorp.

14 recordsLinked to original sources
PubMed1995

Decreased protein synthesis during dry saturation diving.

Changes in metabolism during saturation dives have been reported; however, these changes have not been well defined. This study was conducted to determine the effect of saturation diving on protein metabolism. Whole body protein synthesis was measured by the ammonia and urea endpoint methods, following a single oral dose of 15N-glycine in 11 Navy divers 33.9 +/- 1.9 yr of age. The divers were fed a controlled diet throughout the three trials. Trial I was on the surface, and trials II and III were during dry saturation dives at 0.56 MPa. The protein synthesis results in gram protein per kilogram lean body mass per day, least square mean +/- SD: [formula: see text]. Under the conditions of this series of dry saturation dives, protein synthesis was depressed by up to 30-50% for the urea and ammonia endpoint methods, respectively. An estimate of liver protein synthesis was made by measuring the incorporation of the 15N label into plasma fibrinogen. The 15N enrichment of fibrinogen glycine and the hippurate precursor for fibrinogen were decreased significantly. This dramatic decrease in protein synthesis was observed despite positive nitrogen balance in these divers. Although further investigation is needed to elucidate the mechanism, the decrease in the incorporation of 15N glycine into fibrinogen suggests alteration in liver nitrogen metabolism at 0.56 MPa.

Adult↗
PubMed1994

Energy expenditure and fluid production in hyperbaric He-O2 environments using doubly labeled water.

Energy expenditure (EE), carbon dioxide production (rCO2), water turnover (rH2O), and urine production (UP) were measured to determine nutrient requirements of U.S. Navy divers during saturation dives. Parameters were measured in a normal surface environment (n = 10) and in 0.56 MPa (n = 9) and 3.17 MPa (n = 11) helium-oxygen environments. Daily EE, rCO2, and rH2O were measured with the doubly labeled water method for 10-14 days in each environment. Daily UP was determined by 24-h urine collection for 5- to 10-day periods in each environment. Divers consumed a mixed diet composed of 30% calories from fat, 15% protein, and 55% carbohydrate. Both EE and rCO2 increased significantly relative to surface conditions at 0.56 MPa (13 +/- 4% and 11 +/- 4%) and 3.17 MPa (14 +/- 4% and 11 +/- 3%), but there was no difference between dives. Water turnover was not significantly affected by the hyperbaric environment. UP was significantly greater than surface conditions at 0.56 MPa (53 +/- 19%) but not at 3.17 MPa (38 +/- 18%). Increased EE is attributed to thermal stress caused by the helium-oxygen environment. Increased UP may have been caused by decreased evaporative water loss.

Adult↗
PubMed1992

Management of herniated intervertebral disks during saturation dives: a case report.

During research saturation dives at 5.0 and 5.5 atm abs, 2 divers developed an acute herniation of the nucleus pulposus of the L5-S1 intervertebral disk. In both cases the pain was severe enough to require intravenous morphine or intramuscular meperidine. Although the symptoms presented by these divers are frequently considered to be an indication for immediate surgical consultation, we decided that emergency decompression posed an unacceptable risk that decompression sickness (DCS) would develop in the region of acute inflammation. In both cases strict bedrest and medical therapy were performed at depth. In the first case, 12 h was spent at depth before initiating a standard U.S. Navy saturation decompression schedule with the chamber partial pressure of oxygen elevated to 0.50 atm abs. In the second case, a conservative He-N2-O2 trimix decompression schedule was followed to the surface. In both cases, no initial upward excursion was performed. The required decompression time was 57 h 24 min from 5.5 atm abs and 55 h 38 min from 5.0 atm abs. During the course of decompression, the first diver's neurologic exam improved and he required decreasing amounts of intravenous narcotic; we considered both to be evidence against DCS. The second diver continued to have pain and muscle spasm throughout decompression, however he did not develop motor, reflex, or sphincter abnormalities. Both divers have responded well to nonsurgical therapy.

Adult↗
PubMed1991

Effects of carbohydrate loading and underwater exercise on circulating cortisol, insulin and urinary losses of chromium and zinc.

The effects of carbohydrate loading on relative stress responses of eight male subjects performing intermittent leg exercise at 80% maximum oxygen consumption during headout immersion in 25 degrees C water were tested. Carbohydrate loading increased the number of work cycles completed, with less physical stress compared with that completed following the control diet period. Pre-exercise serum cortisol values were similar on both diets prior to exercise but following exercise control values were greater (1152, 94 vs 858, 77 nmol l-1; mean, SEM). Chromium losses, which have been shown to correlate with stress, were lower during the carbohydrate loading period, 8.6, 1.3 vs 12.4, 2.0 ng h-1, and were correlated with post-exercise serum cortisol. Urinary zinc losses were also lower during carbohydrate loading, while urinary losses of potassium, magnesium and calcium remained constant. Insulin values decreased similarly following exercise in both groups and were not altered by carbohydrate loading. These data demonstrate that carbohydrate loading increases immersion exercise output with less stress as determined by serum cortisol and urinary chromium losses.

Adult↗
PubMed1988

Randomized study of six umbilical cord care regimens. Comparing length of attachment, microbial control, and satisfaction.

Two hundred and seventy one infants were enrolled in a study to compare six different methods of treating the umbilical cord. Antimicrobial control was equal for all methods. Repeated triple dye application was considered least acceptable by staff and parents and had the longest attachment time. Povidone-iodine was associated with the shortest attachment time and was most liked. If there is no special need to treat a specific nosocomial outbreak, duration of cord attachment and satisfaction of staff and parents can help clinicians decide on a cord care regimen.

Administration, Topical↗
PubMed1981

A prospective study of infant zinc nutrition during intensive care.

Zinc nutritional status was evaluated during intensive care for 55 infants. Plasma zinc, serum albumin, alkaline phosphatase, growth, nutrient intake, and clinical data were examined. The more premature infants (less than 32 wk gestational age) had higher zinc levels on admission, but their levels declined more rapidly than in more mature infants. Zinc level did not correlate with albumin or alkaline phosphatase. Low zinc levels (45 microgram/dl or less) occurred at about 6 wk in 14 of 39 premature infants. True zinc deficiency occurred in two premature infants; it was manifest by increased gastric residuals, poor suck, and decreased growth, but neither infant had the skin or gastrointestinal signs generally expected with zinc deficiency. There was evidence that sick premature infants may need more zinc than is currently recommended to supplement parenteral nutrition and more than the amount supplied in premature infant formulas currently available.

Critical Care↗
PubMedDate not supplied

Neonatal hemochromatosis, renal tubular dysgenesis, and hypocalvaria in a neonate.

We report a neonate with neonatal hemochromatosis (NH), renal tubular dysgenesis (RTD), and hypocalvaria. NH is a fatal condition of the newborn, characterized by severe idiopathic liver failure of intrauterine onset and siderosis, intra- and extrahepatic, with sparing of the reticuloendothelial system. RTD is characterized by short, abnormally developed cortical tubules that lack proximal tubule differentiation. Although both NH and RTD have been reported as entities with a genetic component, similar findings can be secondary to in utero insults. Hypocalvaria has been reported in association with fetal hypoxia including that secondary to angiotensin converting enzyme inhibitors. This 38-week-old infant died at 8.5 h. The small nodular liver weighed 44 g. Grossly, the kidneys were normal. Hypocalvaria was present. Microscopically, the hepatic parenchyma was distorted by fibrous tracts, proliferation of bile ducts, and abundant iron deposition in hepatocytes. Extrahepatic siderosis in the pancreas, myocardium, and other organs was consistent with NH. Proximal convoluted tubules were not seen on routine stains and markers for proximal tubules were negative. Previous reports have linked NH with RTD and RTD with hypocalvaria. This infant had all three of these rare conditions, which have been hypothesized or shown to be due to genetic factors, hypoxia, or drugs. The etiology in this case is unknown.

Abnormalities, Multiple↗