Biomedical subjects
Publications and source records attributed to M Ashwell.
CBA mice were made obese by injection with gold thioglucose (GTG). After receiving transplants of "lean" and "GTG-obese" fat under separate kidney capsules, the host mice were fed a restricted diet for three weeks. Over this period, the fat cells in the lean grafts enlarged whereas the fat cells in the GTG-obese grafts shrank. Concurrent fat loss and fat gain can therefore take place.
Human fat cells from lean donors enlarge on transplantation into obese nude mice (genotype ob/ob nu/nu). On transplantation into lean nude mice human fat cells do not change significantly in size, even though they are much larger than mouse fat cells.
Fat cells from the gonadal fat pad of New Zealand obese mice are larger than those from the subcutaneous fat pad. When fat is transplanted to a third, common site (beneath the kidney capsule), this difference in size largely disappears, suggesting it is the location of the fat cells rather than of intrinsic differences between the cells that account for their different sizes.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
1. The aim of this investigation was to ascertain of a variety of obese rodents whether the primary cause of fat cell enlargement lay in the fat cell itself, or in its environment. Rodents studied were the mutant mice 'diabetic' (db/db), 'adipose' (dbad/dbad), and 'yellow obese' (Ay/+), New Zealand obese mice, CBA mice made obese with gold thioglucose, and obese BIO 4.24 hamsters. 2. Gonadal fat of obese or lean genotype was transplanted under the kidney capsule of an obese or lean host. Grafts were left in place for at least one month, then examined histologically to measure fat cell diameters, from which fat cell masses were calculated. 3. Immunological rejection of grafts was avoided either by using mice syngeneic except for the obesity producing mutation (db/db, dbad/dbad or Ay/+) or by transplanting into F1 hybrids (NZO X BALB/c) made by mating the strains acting as donors of obese or lean fat. Transplantation of fat between lean BIO 4.22 hamsters and obese BIO 4.24 hamsters was possible because these had common histocompatibility antigens. 4. In all the forms of murine obesity studied, 'lean' fat cells enlarged in an obese recipient to the size typical of cells in 'obese' fat whilst 'obese' fat cells shrunk in a lean recipient to, at least, the size typical of 'lean' fat. Lean hamster fat cells also enlarged in an 'obese' environment and 'obese' hamster cells shrunk in a 'lean' environment. 5. Environment therefore contributes to the determination of fat cell size in all the rodents studied, and in several rodents (db/db, dbad/dbad, Ay/+, and gold thioglucose obese mice) our results showed that environmental factors are of paramount importance in determining cell size, and factors associated with the fat cell itself make a negligible contribution.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Fat tissue from the genetically obese mouse (C57BL/6J ob/ob) and its lean littermate (+/?) was transplanted into lean hosts(+/+). Chemical induced obesity in the host mice caused no greater increase in the size of 'obese' fat cells than it did in the size of 'lean' fat cells. 'Obese' fat cells, therefore, have no innate capacity for increased fat storage.
Thirty-three obese women were admitted as inpatients to a metabolic ward and had an average intake of 3.35 MJ (800 kcal) daily for three weeks. Fat biopsies were taken at three subcutaneous sites and average fat cell mass (CM) and apparent fat cell number (FCN) were calculated. There was no significant correlation between adipose tissue cellularity (CM or FCN) and total weight loss or resting metabolic rate, provided due allowances were made for the severity of obesity in each case. Neither was there any significant correlation between short-term weight loss and the age of onset of obesity. Resting metabolic rate, and not adipose tissue cellularity or age of onset of obesity, is a better indicator of short-term weight loss under controlled inpatient conditions.
Explore the source record for details and available documents.
A new method of classifying women according to their pattern of fat distribution is discribed. Standard linear-discriminant analysis of data from somatotype photography shows that the most important measurements are those of thigh and waist diameters and a simple ratio of these is proposed as a fat distribution (FD) score, ie one which distinguishes an android or central-type fat distribution from a gynoid or peripheral-type fat distribution: FD score = 26 log10 (formula: see text) The score is shown to correlate positively with age, actual weight and relative weight in 90 subjects, showing that older, fatter women are more likely to have a central-type of fat distribution. The score is also significantly positively correlated with the size of fat cells in the arm and waist measured in 46 subjects, showing that women with central-type fat distribution have larger fat cells in the upper parts of their bodies compared with women with peripheral-type fat distribution. Analysis of FD score before and after weight loss showed no significant correlation between the change in FD score and the degree of weight loss. This suggests that the pattern of female fat distribution as defined by the FD score is relatively constant.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.