Bernard G. Slavin

The cytophysiology of mammalian adipose cells.

Publisher Summary The physiological capacity of typical mammalian adipose cells appears to be 3-fold: (1) the mobilization of stored lipid in the form of fatty acids and glycerol; (2) the uptake of substrates, for example—glucose, fatty acids, amino acids—for energy purposes, lipogenesis, and lipid deposition; and (3) the maintenance of the stored bulk of lipid (triglyceride) by a delicate balance between lipid synthesis and degradation. The mechanisms controlling this balance are now known to be directly related to endocrine and neuroendocrine secretions as well as to the nutritional status of the organism. Such information was gleaned from the data of many investigators, beginning with the studies of Wertheimer and Shapiro who initiated a vast burst of activity concerning the physiological role of adipose tissue in mammals. Before 1940, most investigators considered adipose tissue metabolically inactive, functioning mainly as a supportive material and releasing lipid in a passive manner during a fasting state or absorbing lipid during a refeeding period following a fast. While extensive studies exist in the biochemical and physiological literature concerning the metabolism of adipose cells and tissue, there is an obvious lack of investigations correlating the function of adipose cells with concomitant cytological changes occurring therein. This chapter reports on the present state of knowledge dealing with the purported role of cytoplasmic organelles in the processes of lipid synthesis and mobilization, as well as the role played by other aspects of adipose cell fine structure during these physiological states.

The Pearson Silver-Gelatin Method for Light Microscopy of 0.5-2 μ Plastic Sections

Sections 0.5-2 μ thick of liver, kidney, lung, cartilage and brown fat embedded in Maraglas, Araldrite, Epon and Spurrs medium were deplasticized in alcoholic NaOH for 15 min. Following several alcohol rinses, the tissues were exposed to 2% AgNO3 at 50 C for 1-2 hr, and then developed in a solution containing 3% gelatin, 40 ml; 2% AgNO3, 10 ml; and 1% hydroquinone, 4 ml. Sections were then toned in 1% gold chloride (several dips), washed in water for 5 min and dipped in 2% oxalic acid. After a brief rinse in water the sections were placed in 5% Na2S2O3 for 5 min, washed in water for 5 min, dehydrated in alcohol, cleared and covered. Compared to similar sections retained in plastic and deplasticized sections stained in the routine manner with 1% toluidine blue, silver impregnated sections of all tissue free of plastic, displayed greater clarity of cellular detail. Especially clear were mitochondria of liver and brown fat cells. Type II cells of the lungs were exceptionally prominent as were podocyte foot ...

Histological, Immunocytochemical, and Morphometrical Analyses of Pancreatic Islets in the BSB Mouse Model of Obesity

This article presents biochemical data on the BSB mouse model of multigenic obesity indicating increased percentage body fat, increased fasting plasma insulin, and increased insulin resistance in male and female obese mice compared with lean controls. Plasma glucose was significantly increased only in male obese mice. Morphological and morphometrical analyses of pancreatic islets showed increased islet size and number in all obese mice compared with lean controls. Immuno‐staining results for insulin‐positive islet cells showed greater levels of insulin in male and female obese versus lean mice, while the percent or proportion of insulin immuno‐staining, as expected, was not significantly different between obese and lean. The percent or proportion of immuno‐staining for islet glucagon and somatostatin showed reduced staining in islets from obese compared with lean mice. The significance of these findings shows, for the first time, the morphologic appearance of pancreatic islets and the quantitative distribution of the three major islet cell hormonal populations in BSB obese mice. The correlation between this descriptive information and physiological data might lend insights to the cause of obesity‐related diabetes. Anat Rec, 2010.

Morphological Changes in the Aging Mammalian Pancreas

A comprehensive description of morphological and cytological changes in the aging mammalian pancreas has not been reported. What works have been published consist of light microscopic descriptions of a variety of histopathologic lesions in both the aging exocrine and endocrine pancreas. While this chapter deals specifically with the area of age-related cytomorphologic changes in the mammalian pancreas, emphasis will be placed on a description of the endocrine pancreas. This is not difficult to understand in light of the relationship of the endocrine pancreas to diabetes mellitus, a disease mainly of the aged population.