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Biomedical subjects

J L Knittle

Publications and source records attributed to J L Knittle.

6 recordsLinked to original sources
PubMed1979

The growth of adipose tissue in children and adolescents. Cross-sectional and longitudinal studies of adipose cell number and size.

Adipocyte size and number were determined in 288 subjects ranging in age from 4 mo to 19 yr. The study was performed in 110 obese and 178 non-obese subjects. 4-yr, longitudinal, follow-up studies were also performed in 132 subjects. The results demonstrate that the contribution of cell number and size to the growth of the fat depot in nonobese children varies with age. Deviations from this normal development were observed in obese children shortly after 1 yr of age. By 11 yr of age obese children exceeded the mean cell number found in nonobese adults. Indeed, obese subjects displayed more rapid and earlier elevations in both cell number and size, which were maintained throughout the study. Thus obese children display both quantitative and qualitative differences in fat tissue development when compared to nonobese children. The data indicate that the rate and type of adipose tissue cellular development one encounters in children may play a role in the development of the enlarged fat depots found in obese subjects.

Adipose Tissue↗
PubMed1975

Observatons on the growth and metabolic functions of cultured cells derived from human adipose tissue.

The growth and metabolic activity of cultured cells derived from human adipose tissue (CAT cells) were studied and compared to cultured skin fibroblasts. The morphological appearance of the CAT cells was distinctly different from that of fibroblasts. The growth rate of CAT cells as measured by 3H-thymidine incorporation was much slower than the fibroblast growth rate. Cultured CAT cells synthesized significantly 14C-glucose, while fibroblast cultures had a higher metabolic rate as measured by CO2 production. Insulin stimulated 3H-thymidine incorporation in both CAT and fibroblast cultures. The CAT cells did not show a consistent insulin response of lipid or CO2 production, but this may be a reflection of donor age or nutritional status. Even though the CAT cell may be a type of stromal cell peculiar to adipose tissue rather than a preadipocyte or adipocyte, it may prove useful in studies of human obesity.

Adipose Tissue↗
PubMedDate not supplied

Effects of hypocaloric diet low in essential fatty acids on in vitro human adipose tissue prostaglandin production and essential fatty acid status.

Very-low-calorie, fat-free defined-formula diets have been routinely used to treat obese patients. However, the effect of feeding a defined-formula diet low or devoid of essential fatty acids (EFAs) on EFA metabolism has not been determined. The aim of this investigation was to determine the effect of 400 kcal/day of Optifast 70 on EFA metabolism as determined by serum and adipose tissue levels of omega-6 fatty acids and measurements of in vitro human adipose tissue prostaglandin production. Five obese subjects entered the study after 1 wk of weight maintenance and then were placed on 12 wk of weight reduction. Blood and tissue samples were obtained before and after 4, 8, and 12 wk of weight reduction. Subjects tolerated 12 wk of dieting without any adverse reactions and lost an average of 21.7 +/- 7.0 kg. There was no significant effect of weight reduction on the levels of linoleic or arachidonic acid found in adipose tissue. There was a significant decrease in adipose tissue prostaglandin production of prostacyclin I2, measured as 6-keto-PGF1 alpha, after 12 wk of weight reduction. There was no significant change in the levels of thromboxane A2, measured as TXB2. There was a significant increase in serum arachidonic acid levels with no change in linoleic acid levels. The results demonstrated that the use of a diet devoid of EFA had no significant effect on omega-6 EFA metabolism as measured by serum and tissue levels and the ability of adipose tissue to produce prostaglandins in vitro.

Adipose Tissue↗