Histo- and cytophysiology of the lactating mammary gland of the African elephant (Loxodonta africana).

The lactating mammary gland of the African elephant (Loxodonta africana) has been studied with a panel of morphological techniques focusing on (1) the functional changes during the secretory process, (2) proliferative process [by application of proliferating cell nuclear antigen (PCNA) immunohistochemistry] and apoptotic phenomena [by use of the TUNEL technique] in the individual lobules, and (3) components of milk and milk-fat-globule membrane. In the lactating gland, the lobules are variably differentiated; within a lobule, however, the alveoli are usually similarly differentiated. The morphology of their alveoli suggests a classification of the lobules into types 1-3.

High pressure effects on the colloidal calcium phosphate and the structural integrity of micellar casein milk. Part 1. High pressure dissolution of colloidal calcium phosphate in heated milk systems.

Results of this study confirm that high temperature (118 degrees C/15 min) and high pressure (400 MPa/5 min) processing of skim milk, skim milk ultrafiltration and ultracentrifugation fractions, and model milk salt solutions cause dramatic shifts in their colloidal and soluble Ca phosphate equilibrium that affect their pH, dissolved Ca content, turbidity, and casein micelle microstructure. The relations between high temperature and high pressure processing-induced changes in the colloidal and soluble Ca phosphate equilibrium were evaluated in raw, pasteurized, and high temperature treated skim milk, ultrafiltration retentate and permeate of pasteurized skim milk, clear ultracentrifugation infranatant of pasteurized skim milk, and synthetic milk ultrafiltrates with and without lactose or Ca. The magnitude of the pH and dissolved Ca shifts caused by high temperature and high pressure processing was a function of casein micelle concentration.

Histochemical and biochemical observations on milk-fat-globule membranes from several mammalian species.

A specific secretory product of the lactating mammary gland are triglyceride fat globules which are enveloped by a very complex membrane, the milk fat globule membrane (MFGM). In different mammalian species (man, rhesus monkey, horse, goat, sheep, cow, grey seal, camel, alpaka) the glycoproteins of this membrane have been analyzed by gel electrophoresis, Western blotting and lectin histochemistry. A remarkable intra- and interspecific variability of these glycoproteins has been detected pointing to so far unknown physiological adaptions, which may play a role in the intestine of the new born.

Structural, histochemical and biochemical observations on horse milk-fat-globule membranes and casein micelles.

Horse milk fat globules (MFGs) and casein micelles were studied using freeze fracturing, freeze etching and thin-section electron microscopy, as well as lectin histochemistry, gel electrophoresis, and Western blotting. Horse MFGs were found to be relatively small, their average volume-surface diameter being about 2.75 microns.

Glycoprotein filament removal from human milk fat globules by heat treatment.

Freeze-etch electron microscopy was applied to milk fat globules to observe surface details. A remarkable array of filaments, approximately 0.5 micron in length, was seen on human, but not bovine, globules.