Search PubMed⌕ Search

Biomedical subjects

E W Nelson

Publications and source records attributed to E W Nelson.

At least 55 records · Page 3Linked to original sources
PubMed1983

Computerized tomography in the evaluation of blunt abdominal trauma.

Computerized tomography has proved useful in the evaluation of selected patients suffering blunt abdominal trauma. Seventeen patients with major multisystem injuries were treated using a protocol involving abdominal computerized tomographic scans for evaluation of intraabdominal injury. Significant solid organ injury was accurately diagnosed in 10 of 17 patients, 2 of whom eventually required surgical treatment. The remainder of the patients with intraabdominal solid organ injury diagnosed by computerized tomographic scan were followed under strict guidelines and recovered without surgery. Computerized tomography represents a quick, accurate diagnostic technique for dealing with blunt abdominal trauma in selected multiply injured patients.

Abdominal Injuries↗
PubMed1983

The effect of diphenylhydantoin (phenytoin) on the sequential stages of intestinal folate absorption.

The drug diphenylhydantoin (phenytoin) (DPH) is thought to interfere with the bioavailability of dietary folate through an effect on intestinal folate deconjugation and/or monoglutamate folate transport. In order to determine whether DPH inhibition occurs in the sequential steps of folate deconjugation, uptake, or reduction-methylation, the effect of the drug on the intestinal absorption of hexaglutamate folate (PteGlu6), pteroylmonoglutamate folate (PGA), and N-5-methyltetrahydrofolate (CH3FH4) was studied. Folate absorption was directly quantified by the method of triple lumen tube perfusion in 12 subjects serving as their own controls. All 12 received PGA mixed with and without DPH (20 micrograms/ml), while 6 of the 12 subjects received hexaglutamate and 6 received reduced methylated folate with and without added DPH. With this model DPH was shown not to impair significantly folate absorption by any action upon the process of folate deconjugation, absorption, or reduction-methylation. The previously reported association between DPH intake and reduced levels of serum folate remains unexplained by these studies.

Adult↗
PubMed1982

Percutaneous placement of Hickman catheters for prolonged venous access.

The Hickman catheter is well established as a safe, reliable means of venous access in a variety of clinical situations. Although the technique for placement by surgical cutdown in the cephalic or external jugular vein is standardized, our experience placing 102 catheters in the last 40 months has led us to evolve and adopt a percutaneous method that we have now applied to almost all catheter placements. Operative time has been dramatically reduced, patient discomfort minimized, and no change in short- or long-term morbidity had been noted. The procedure has been described in detail, and our overall experience with placement of the Hickman catheter in a variety of clinical situations has been reviewed. We now consider this percutaneous technique to be the primary method of Hickman catheter placement unless specifically contraindicated.

Adolescent↗
PubMed1979

Ultrasonographic demonstration of the pancreatic duct.

During a 4-year period, 375 patients with clinically suggestive pancreatic disease were examined with gray scale ultrasound. In 14 patients, the pancreatic duct itself was demonstrated. All of these had clinical or laboratory evidence for, and radiologically or surgically proven, pancreatic duct obstruction. Etiology of the obstruction was either tumor, chronic pancreatitis, pancreatic abscess, pseudocyst, or stricture of the duct at the papilla of Vater. Two patients had Crohn's disease of the duodenum.

Adult↗
PubMed1979

Severe diarrhea secondary to propranolol.

We have described two patients with propranolol-induced severe diarrhea, confirmed by rechallenge with the drug. In both cases the diarrhea was readily reversible with discontinuation of the drug.

Atrial Flutter↗
PubMed1978

Demonstration of saturation kinetics in the intestinal absorption of vitamin C in man and the guinea pig.

Intestinal absorption of ascorbic acid is believed to be mediated through a sodium-dependent active transport process in man and in the guinea pig, both species having a nutritional requirement for the vitamin. Vitamin C transport was studied in man and in the guinea pig by in vivo intestinal perfusion of concentrations of vitamin C ranging from physiologic to clearly pharmacologic levels. Triple lumen intestinal perfusion of seven human volunteers with vitamin C concentrations ranging from 0.85 to 11.36 mM demonstrated saturation kinetics of absorption with a Km = 5.44 mM. Net secretion of water was observed in three of seven humans with the highest (11.36 mM) concentration of vitamin C. Perfusion of isolated segments of guinea pig intestines with intact blood supply also revealed saturation kinetics (Km = 5.54 mM) in the range of 1.42 to 56.8 mM vitamin C but linear absorption below this range. The phenomenon of decreased water absorption noted with incremental vitamin C dose in human volunteers could not be reproduced in the guinea pig, nor were the intestinal tissue levels of cyclic AMP and GMP increased by high-dose vitamin C in this species. This study suggests that "megavitamin" doses of vitamin C (greater than 1 Gm) are probably not as efficiently absorbed as smaller multiple doses of the vitamin. Intestinal secretion of water may contribute to the diarrhea which is the most common side effect of large doses of vitamin C. The guinea pig is a useful but limited model for vitamin C absorption in man.

Adult↗
PubMed1978

Accuracy and consistency of pancreatography.

Pancreatography is a valuable diagnostic technic to identify structural changes in the pancreatic ductal system. Although specific diagnoses based on ductal changes are not always possible, patients with surgically normal glands and those showing changes of chronic pancreatitis were reliably identified in this series. Patients evaluated for postcholecystectomy pain usually had normal pancreatograms and grossly normal pancreatic glands at the time of surgical exploration. The overall consistency in interpretation of pancreatograms by experienced radiologists was approximately 80 per cent. Pancreatic cancer was poorly predicted due to either minimal changes in the ductal system or inability to distinguish gross changes from those seen with chronic pancreatitis.

Adult↗
PubMed1978

Effect of diphenylhydantoin on the bioavailability of citrus folate.

Long term use of the drug diphenylhydantoin (DPH) has been associated with biochemical evidence of folic acid deficiency and rarely with megaloblastic anemia. The mechanism of this nutritional deficiency is uncertain but is thought to result from DPH-induced alteration in the intestinal absorption of conjugated and/or free dietary folate. The effect of DPH on the intestinal absorption of free folates from a food source has heretofore not been reported. In this study triple lumen tube perfusion of the human jejunum was used to quantitate folate absorption from a control solution of orange juice and from an identical solution containing DPH. The results in eleven volunteers serving as their own controls indicate no effectof DPH at a concentration of 20 microgram/ml on folate absorption from this food source. The predominant form of folate in orange juice as determined by differential microbiologic assay is N-5-methyltetrahydrofolate. DPH does not appear to interfere with the absorption of free food folate which is both methylated and reduced.

Adult↗
PubMed1978

Effect of physical activity on human potassium metabolism in a hot and humid environment.

Previous investigations have suggested that there are high potassium losses during heavy physical activities in hot climates. In order to determine if high levels of potassium losses could be offset by potassium loading, this study was conducted with five long-distance track runners who had trained in hot and humid environments. The liquid supplements containing 4.3, 98.0, and 0.0 mEq/liter of potassium were given 1 to 2 hr before physical activity. The daily diet contained 2.6 g of potassium. A sodium and potassium balance study was conducted in which stool, urine, and dermal losses were measured. In order to determine if there was a change in the distribution of body potassium during physical exercise, seven subjects total body potassium was estimated before and after exercise. This measurement was performed by counting 40K in a whole body counter. Although the subjects with potassium supplementation and higher urinary sodium and potassium losses, the 98 mEq/liter of potassium supplement resulted in a positive potassium balance. The subjects' potassium requirements exceeded the National Research Council suggested dietary intake. The total body potassium measurements indicated that the counting efficiency of 40K increases significantly immediately after the period of vigorous exercise.

Adult↗
PubMed1977

Spontaneous hepatic rupture in pregnancy.

Hepatic rupture as a late complication of toxemic pregnancy is a rare yet lethal condition requiring rapid recognition and surgical management. The clinical triad of toxemia, right upper quadrant pain, and sudden hypotension is the diagnostic hallmark of presentation. Most patients present near the time of delivery and are found to have subcapsular hematomas of the right hepatic lobe with free rupture into the peritoneal cavity and resultant exsanguinating hemorrhage. The association of toxemia and disseminated intravascular coagulation with secondary microembolic damage to the liver and other organs has been discussed. Basic surgical principles in the managment of hepatic subcapsular hematomas, and the prolonged postoperative course and frequent complications in these patients have been stressed.

Adult↗
PubMed1977

Characterization of food binding of vitamin B-6 in orange juice.

There is substantial evidence that natural vitamin B-6 exists largely in a bound form. It has been shown that the principal modes of binding represents an interaction of pyridoxal and/or pyridoxal phosphate with protein moieties. The nature and extent of binding of different forms of the vitamin in orange juice was investigated. Studies employing ultracentrifugation, ultrafiltration and, membrane dialysis of this food product suggested binding to a molecule of less than 3,500 daltons molecular weight. Binding was resistant to protease treatment although susceptible to heat-acid hydrolysis. Separation of pyridoxal, pyridoxine, and pyridoxamine species of the vitamin by ion exchange chromatography was followed by fluorometric analysis with and without preparative hydrolysis. Extensive and equal binding of both pyridoxal and pyridoxine was observed by this method. Thus, the binder(s) of vitamin B-6 in orange juice is a small dialyzable molecule which is heat stable, binds both pyridoxal and pyridoxine and is non-protein in nature.

Citrus↗
PubMed1977

An in vivo preparation (Thiry-Vella fistula) suitable for the measurement of intestinal absorption in the guinea pig.

A thiry-Vella isolated intestinal loop was constructed in the guinea pig. The procedure consisted of removal of a 30-cm segment of the jejunem, restoration of intestinal continuity by a jejunojejunostomy, and exteriorization of the segment through stomata sutured to the skin. The procedure was performed on seven guinea pigs of which three survived. The three survivors remained normal in maintenance of hair, feeding, and weight gain over a long period.

Animals↗
PubMed1976

Comparative human intestinal bioavailability of vitamin B-6 from a synthetic and a natural source.

Intraluminal perfusion of human jejunum has not been previously reported to demonstrate differences in bioavailability of vitamins from a food product. In this report, a triple lumen tube with a 30 cm study segment was used to study water soluble vitamin absorption in 15 normal subjects serving as their own controls. The intestinal uptake of vitamin B-6 from organ juice (O) and from a synthetic solution (S) perfused at 7.6 ml/minute were compared. In a separate series of perfusions in six subjects, the absorption of a mixture pf pyridoxine, pyridoxal, and pyridoxamine from O and S solutions with and without glucose were compared. Mean vitamin B-6 absorption was significantly greater from S (65% uptake, transport rate 0.71 mug/cm/hour) than from 9 (30% uptake, transport rate 0.40 mug/cm/hour, p less than 0.05). The addition of glucose to S enhanced this difference. Triple lumen intestinal perfusion can be used to discriminate difference in bioavailability of water soluble vitamins from natural and synthetic sources.

Biological Availability↗