To clarify the oxidant defense functions of reduced glutathione (GSH) in erythrocytes, the effect of GSH deficiency on in vitro oxidant defense was studied, using GSH-deficient sheep erythrocytes (low-GSH cells). The formation of Heinz bodies in low-GSH cells was higher than that in high-GSH cells when the cells were incubated with an oxidant drug, acetyl-phenylhydrazine (APH). Artificial depletion of GSH by 1-chloro-2,4-dinitrobenzene in high-GSH cells resulted in increased Heinz body formation in these cells incubated with APH. Furthermore, high negative correlation was observed between Heinz body formation and GSH content in sheep erythrocytes exposed to APH. These results clearly indicate that erythrocyte GSH is indispensable for erythrocyte defense against oxidative damage induced by APH, and support the previous observations that sheep with low-GSH erythrocytes were more susceptible to oxidative agents than were sheep with high-GSH erythrocytes.

In this study, we compared hepatic ultrastructure in healthy cats, in cats with severe hepatic lipidosis, and in cats with experimentally induced, chronic, extrahepatic bile duct occlusion. Ultrastructural features unique to the lipidosis syndrome included an apparent reduction in number of peroxisomes and alteration in their morphologic features. The quantity of endoplasmic reticulum, Golgi complexes, and lysosomes was subjectively reduced, and paucity of cytosolic glycogen was observed. Bile canaliculi appeared collapsed because of cytosolic distention with lipid. Mitochondria were reduced in number and were markedly pleomorphic. Cristae assumed a variety of shapes, lengths, and orientations. Ultrastructural features of bile duct occlusion were similar to those described in other species and differed from those in cats with hepatic lipidosis.

Ultrastructures of knobbed spermatozoa in a boar were observed. The knobs, found at the apex of the spermatozoa, were spherical swellings of the acrosome; vacuoles were found in the swellings. According to the contents, 2 types of the vacuoles were recognized: a vacuole containing cell debris that was surrounded by 2 or 3 layers of membranes, and a vacuole containing an amorphous material that was surrounded by a single membrane. Several vacuoles might be observed in a knob. Observations of both testes indicated that the cell debris in the vacuole of the knob was derived from the cytoplasm of the Sertoli cell, which evaginated into the spermatid. Origin of the amorphous material in the other type of knob is not known.

The ionophore A23187 was used to facilitate release and continued development of Anaplasma marginale in short-term erythrocyte cultures. Addition of 10 micromolar A23187 to the cultures resulted in significant decrease in percentage of parasitized erythrocytes (PPE) by 24 hours after treatment; further development and increase in PPE was not observed. In contrast, the PPE of untreated cultures, those treated with dimethyl sulfoxide (DMSO) only and with 1 micromolar A23187 increased slightly during that time. Total erythrocyte count decreased in treated cultures in excess of that expected after samples of the medium were taken for analysis. The greatest cell loss and increased hemoglobin concentration in culture medium was observed in cultures treated with 10 micromolar A23187 and with an equivalent volume of DMSO. The DMSO appeared to cause hemolysis of some erythrocytes, but not of infected cells selectively. Release of A. marginale inclusion bodies was seen by electron microscopy in samples from the 10 micromolar A23187-exposed cultures. At 30 minutes after treatment, free initial bodies were frequently seen. Inclusion body membranes and individual A. marginale were associated with membranes of adjacent erythrocytes. Individual rickettsiae were seen in cell depressions and appeared to be entering erythrocytes. However, neither further invasion nor development of the parasite in erythrocytes was observed. Ionophore A23187 appeared to promote release of A. marginale from erythrocytes, but did not enhance infection of erythrocytes or development of organisms in vitro.

Sequential assessments of pancreatic structure and function were performed on a female German Shepherd Dog bred from parents with exocrine pancreatic insufficiency (EPI), to monitor development of pancreatic acinar atrophy in this breed. Determinations of serum trypsin-like immunoreactivity (TLI), results of N-benzoyl-L-tyrosyl-P-aminobenzoic acid test, fecal soy bean stimulation test (SST), and gross and histologic examinations of the pancreas did not provide evidence of exocrine pancreatic disease up to 13 months of age. However, electron microscopy revealed degenerative abnormalities of acinar cells that were already apparent at 6 weeks and became more extensive with age. Examination of the pancreas at 22 months of age also indicated no gross or histologic abnormalities, but electron microscopy revealed widespread degenerative changes, including dilatation of the rough endoplasmic reticulum and extensive fusion of zymogen granules affecting most of the acinar cells. Serum TLI concentration nm markedly reduced at that time, indicative of EPI, but the dog remained healthy and results of the SST were normal. Within 1 month, the dog had developed clinical signs of EPI, and not only serum Tli concentration, but also results of the N-benzoyl-L-tyrosyl-P-aminobenzoic acid test and SST were compatible with severe loss of exocrine pancreatic tissue. This loss was confirmed by gross and histologic examination of the pancreas at 25 months, which revealed typical features of pancreatic acinar atrophy, including scattered and disorganized exocrine cells in the small remnants of pancreatic tissue. These findings indicate that in German Shepherd Dogs, pancreatic acinar atrophy may involve interference with normal intracellular processing of