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Biomedical subjects

C Lewis

Publications and source records attributed to C Lewis.

At least 235 records · Page 13Linked to original sources

Contrasting effects of the stomach and small intestine of rats on copper absorption.

Since the severity of copper deficiency has been shown to be enhanced by feeding diets containing fructose but ameliorated by diets containing starch, we decided to investigate the effect of fructose or starch on copper absorption. As copper transport has been reported to occur also from the stomach, it was possible that copper absorption is inhibited by fructose already from that tissue. Under anesthesia, stomachs of 72 rats fed copper-deficient or supplemented diets containing fructose or starch were ligated prior to the oral administration of 64Cu. Gastric absorption of 64Cu was studied when the isotope was administered by gastric tube either in diet containing fructose or starch or in water. 64Cu was not absorbed from the stomach regardless of the type of dietary treatment, copper status or whether the copper was administered either in diet or in water. In addition, the absorption of 64Cu from a diet containing either fructose or starch or from a saline solution was studied using the isolated ligated duodenal loop. When 64Cu was administered with dietary fructose 64Cu retention and absorption were impaired when compared to starch. When 64Cu was administered in saline solution, differences in retention and absorption between the four dietary groups disappeared. It is suggested that the requirements for copper rather than the decreased absorption of copper are responsible at least in part for the more pronounced severity of copper deficiency in rats fed fructose compared to those fed starch.

Absorption↗

Female rats are protected against the fructose induced mortality of copper deficiency.

Experiments were conducted in copper deficient male and female rats fed diets containing fructose or starch in order to determine whether the same type of interaction between copper status and dietary carbohydrate found in male rats also occurs in the female rat. Mortality occurred only in the male rats fed the fructose diet deficient in copper with 40% of the animals dying during the 8 week study. Only anemia, hypercholesterolemia, increased BUN, heart hypertrophy and reduced body weight were observed in these animals which could be related to their mortality. Despite the increased mortality, plasma ceruloplasmin, erythrocyte SOD and hepatic copper concentrations were reduced to a similar extent in all rats regardless of the sex of the animals or of the type of dietary carbohydrate fed. The results of the present study indicate that although direct measurements of copper status of female rats fed fructose diet deficient in copper are similar to their male counterpart, they are apparently protected from the lethal consequences of the deficiency.

Anemia↗

Adenoviruses and pediatric gastroenteritis.

Adenoviruses were found in 8.6% of 900 pediatric inpatients with diarrhea who were tested by electron microscopy of a fecal specimen and cell culture inoculation of a throat swab and an anal swab specimen. In 5.1% of these patients, including 13.5% of patients who were four through five months of age, adenovirus particles were visualized in the fecal specimen. Controlled study demonstrated that visualized adenoviruses, especially those that did not grow readily in conventional Hep-2 cell cultures, were significantly associated with diarrhea. About 80% of the visualized adenoviruses from patients with diarrhea or vomiting or both, including 94% of the viruses that grew in the 293 cell line but that did not grow readily in Hep-2 cultures, proved to be enteral adenoviruses--adenoviruses from either group F (type 40) or group G (type 41). Inpatients with gastroenteritis and confirmed enteral adenoviruses ranged in age from one through 16 months, with a median age of seven months. Enteral adenoviruses apparently are endemic in this locale, as one or more of these viruses have been found in every calendar month for nine successive years.

Adenoviridae Infections↗

Mammalian cell culture: technology and physiology.

During the last decade phenomenal advances have taken place in large-scale mammalian cell culture both for microcarriers and suspension methods. The cost of serum and product quality require that such systems be examined in terms of both their physical and chemical parameters. Data are presented as to the method used to more than double the final harvest cell density of 100-liter batch culture reactors by simple temperature measurements and 12-liter reactors by increasing the oxygen potential of the liquid. The results are interpreted in terms of physical transport phenomena of momentum, heat and mass via the theoretical relationships of Navier -Stokes, Fourier and Fick respectively. In addition, data are presented of 3-, 12-, and 100 liter reactors that the spent cell growth media were analyzed for ten different chemistries. The Monod cell growth curve was used to interpret the results. The cost savings and product quality improvements can be enormous by approaching both the technology and physiology of mammalian cell culture from the vantage points of chemistry, thermodynamics and transport phenomena.

Animals↗

The relationship between cardiac output and effective renal plasma flow in patients with cardiac disease.

The relationship between effective renal plasma flow (ERPF) and cardiac output was examined in 46 patients (22 with congestive heart failure and 24 following cardiac surgical procedures) by simultaneously measuring the global ERPF by the single-injection method and cardiac output by the thermodilution method. Of the patients in the heart-failure group, 21 also had pulmonary artery end diastolic pressure (PAEDP) recorded at the same time. ERPF and cardiac output were found to be related by the regression equation: cardiac output = 2.08 +/- 0.0065 ERPF (r, 0.80), with a SE of estimate of 0.81 l/min. ERPF and PAEDP were related by the regression equation: PAEDP = 45.02-0.0675 ERPF (r, 0.86), with a SE of estimate of 5.5 mm Hg. ERPF may be a useful noninvasive method of estimating cardiac output if it is known that no intrinsic kidney disease is present, and if the error of 0.81 l/min (1 SE of estimate) is within the range of clinical usefulness. The error is principally attributable to the determination of cardiac output by the thermodilution method.

Adult↗