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A histochemical study of aldehyde fuchsin-positive material and "high-esterase cells" in the pineal gland of the Mongolian gerbil.

The pineal gland of the Mongolian gerbil consists of a superficial gland, stalk and deep pineal. The deep pineal differentiates postnatally. Histochemical studies of the superficial pineal gland indicate that it may be involved in the secretion of protein. Presumptive secretory material visualized by aldehyde fuchsin (AF) and chrome hematoxylin was observed along the course of blood vessels and among the pinealocytes. The distribution and texture of the AF-positive material was distinctive. It did not correspond to the pattern and texture of material stained with PAS, Sudan Black or acid orcein. Staining with AF was markedly reduced after incubation with trypsin, indicating that the AF-positive material is at least partially protein. The amount of stainable material increased with age. The AF-positive material was observed in what appeared to be interstitial or glial cells and processes, and in the processes of perivascular cells. Cells and fibrous processes with high non-specific esterase activity ("high-esterase cells") were observed among the pinealocytes and along the course of blood vessels. The distribution of the "high-esterase cells" and the morphology and texture of their esterase-containing processes were remarkably similar to the morphology and distribution of the material that stained with AF. It may be that the "high-esterase cells" contain AF-positive material. The "high-esterase cells" hydrolyzed both alpha-naphthyl acetate and alpha-naphthyl butyrate. The pinealocytes hydrolyzed only alpha-naphthyl acetate. The "high-esterase cells" appear to form a distinct class of cells within the superficial pineal gland. They are tentatively identified as a type of glial cell.

Acid Phosphatase

Delayed pentobarbital administration limits ischemic brain damage in gerbils.

The capacity of delayed barbiturate administration to limit brain damage after unilateralcerebral ischemia was examined histologically in gerbils. The right common carotid artery was occluded in 50 animals under brief (3-minute) halothane anesthesia; 18 animals (36%) developed motor abnormalities consistent with stroke. The arterial clasps were removed after 1 hour and the abnormal animals were divided into treatment and placebo groups. Treated gerbils received sodium pentobarbital (70 mg/kg) intarperitoneally 1 hour after clasp removal and a smaller dose (50 mg/kg) 2 hours later; these animals lost corneal reflexes but retained spontaneous respiration and were kept normothermic. Animals in the placebo group received equivalent volumes of normal saline. Except for the period of anesthesia, both groups had similar postischemic motor behavior. Neuropathological examination of animals killed by perfusion-fixation after 24 hours revealed fewer pentobarbital-treated animals with shift of midline structures and with ipsilateral ischemic damage (including infarction). Compared with the placebo group, there was less extensive neuronal ischemic cell change in five regions of the ipsilateral cerebral hemispheres of the pentobarbital-treated animals (p less than 0.05). The results suggest that barbiturates administered as long as 1 hour after the end of an ischemic insult can still limit brain damage.

Animals

Selective chromatolysis of neurons in the gerbil brain: a possible consequence of "epileptic" activity produced by common carotid artery occlusion.

Unilateral (50 to 118 minutes) and bilateral (2 to 33 minutes) carotid artery occlusion in gerbils resulted in two distinct types of neuronal alteration: ischemic cell change (ICC) in selectively vulnerable brain regions, and selective chromatolysis (SC) confined to the deeper layers of the cortex, the Sommer sector of zone h-1, and the paramedian region (PM) of the hippocampus. In typical SC the nucleus was eccentric and the Nissl substance was lost in the central eosinophilic cytoplasm. In electron micrographs this area of cytoplasm showed disruption of smooth and rough endoplasmic reticulum with disaggregation of polyribosomes and accumulation of mitochrondria and various dense bodies. SC was identified at 2 to 3 hours and was still recognizable at five days. When bilateral carotid artery occlusion lasted 5 to 6 minutes, SC was seen in the hippocampal Sommer sector and cerebral cortex, while ICC was restricted to the endfolium (h3-5). Unlike ICC, the frequency of SC was not related to the duration of ischemia but probably to the epileptic seizures (overt and subclinical) initiated by ischemia in the gerbil. These changes must be considered when the gerbil is employed as a model of experimental stroke.

Animals

Interaction of immunoglobulin fragments with the mammalian sperm acrosome.

A study was made of the interaction of immunoglobulins and immunoglobulin fragments from sera of rabbits and pigs with the acrosomes of ten species of mammalian spermatozoa to investigate previous reports of an interaction between normal serum and the acrosome. It was shown that this could be predominantly attributed to IgC, although there was weak staining due to IgM. Further, it was shown that IgG interacted through the Fc fragment, the Fab fragment causing only weak staining of homologous spermatozoa.

Acrosome

Aldehyde dehydrogenase of the Mongolian gerbil, Meriones unguiculatus.

The aldehyde dehydrogenase (Aldehyde:NAD(P) oxidoreductase E.C. 1.2.1.3. and 1.2.1.5) phenotype in several tissues of the Mongolian gerbil, Meriones unguiculatus, has been established. The tissue distribution of gerbil aldehyde dehydrogenase is similar to that of the rat, with liver possessing the majority of the aldehyde dehydrognease activity. Male kidney and testis possess significantly more activity than female kidney and ovary. The substrate and co-enzyme specificity of gerbil liver aldehyde dehydrogenase is also similar to that of rat and mouse liver. Gel isoelectric focusing resolves one major gerbil liver aldehyde dehydrogenase isozyme at pI 5.3. Mouse liver is resolved into two major isozymes at pIs 5.3 and 5.6 and rat liver aldehyde dehydrogenase into one major isozyme at pI 5.4. Gerbil liver aldehyde dehydrogenase is functional over a broad pH range with an optima at pH 9.0. Rat and mouse liver aldehyde dehydrogenase possess sharp pH optima at pH 8.5.

Aldehyde Oxidoreductases

Pyridine nucleotide oxidation-reduction state of the cerebral cortex in the awake gerbil.

A new approach to study the effect of ischemia on the brain of the awake gerbil is described. The measurement of NADH fluorescence from the surface of the cortex is done by a time-sharing fluorometer/reflectometer connected to the brain via a flexible light guide and an implanted cannula. The response of the gerbil brain to anoxia and spreading depression is described. By unilateral occlusion of the carotid artery an increase in NADH was measured in the ipsilateral hemisphere.

Animals

Prostaglandin prodrugs. I: Stabilization of dinoprostone (prostaglandin E2) in solid state through formation of crystalline C1-phenyl esters.

Dinoprostone para-substituted phenyl esters were synthesized in attempt to improve the solid-state stability of the parent prostaglandin. A phenol series covering a wide melting-point range was employed, and a linear relationship was observed between the phenol melting points and the resulting prostaglandin C1-ester melting points. The crystalline esters showed improved solid-state stability over the parent compound, and many esters were biologically active.

Animals

Prostaglandin prodrugs III: Synthesis and biological properties of C9- and C15-monoesters of dinoprost (prostaglandin F2 alpha).

Methods are described for the synthesis of dinoprost C9- and C15-monoesters using protective groups. Esters at C9 were synthesized by acylation of dinoprost 11,15-bis(tetrahydropyran-2-yl)ether followed by acid-catalyzed protective group removal. Esters at C15 were synthesized by initial formation of the protected intermediate, dinoprost 9,11-n-butylboronate, followed by acylation and hydrolytic protective group removal. Many esters were active in vivo in the hamster antifertility screen. Plasma hydrolysis studies showed that the C15-esters were more readily cleaved than the C9-esters. In vivo studies in the rat showed that both the C9- and C15-esters resulted in urinary excretion of 5 alpha, 7 alpha-dihydroxy-11-ketotetranorprosta-1,16-dioic acid in amounts comparable to those obtained after dosing with dinoprost, indicating that ester hydrolysis occurred in vivo.

Animals

Plasmalogenase is elevated in early demyelinating lesions.

Plasmalogenase catalyzes the hydrolysis of ethanolamine plasmalogens to long-chain aldehydes and 2-acyl-sn-glycero-3-phosphoethanolamines. During development, plasmalogenase activity parallels myelination. The enzyme is most concentrated within oligodendroglial cells and is absent from myelin. The normal function of plasmalogenase in white matter may be related to its specificity for plasmalogens that contain most of the thromboxane and prostaglandin precursors. Plasmalogenase activities are elevated in demyelinating CNS tissues including canine white matter with lesions due to distemper virus. Elevated plasmalogenase activity precedes cellular invasion and lysosomal activation as indicated by beta-glucuronidase, acid proteinase and neutral proteinase activities. The elevation of plasmalogenase activity was 4.9-fold greater than normal in an early demyelinating lesion caused by the Snyder-Hill strain of distemper virus. Phospholipases acting on phosphatidyl ethanolamine were not activated in this tissue and have activities much lower than plasmalogenase in control tissues. Plasmalogenase activities are also elevated after intracerebral injections of complement-dependent anti-myelin antibody and after ischemia. Plasmalogenase acting on the oligodendrocyte plasma membrane may be responsible for necrosis of the oligodendrocyte that results in demyelination.

Animals

On the occurrence of argyrophil cells in salivary glands.

Salivary glands (parotid, submandibular and sublingual glands) of nine mammalian species were investigated with respect to presence and localization of argyrophil and argentaffin cells. With the exception of the parotid gland of the rat, no positive staining was observed within the examined glands. In the rat parotid distinctly argyrophil cells could be demonstrated in the intercalated ducts. Histochemical studies of the cells, ultrastructural analysis of their cytoplasmic granules as well as their reactions to certain drugs indicate that these cells are of exocrine rather than of endocrine nature. After a subcutaneous injection of pilocarpine, the intensity of the argyrophil staining was markedly reduced. No specific catecholamine fluorescence could be detected within the cells, not even after pretreatment of the animals with high doses of L-DOPA. The membrane-bounded cytoplasmic granules of the intercalated duct cells furthermore displayed a strong positive staining reaction after treatment of ultrathin Vestopal sections with the periodic acid-chromic acid-silver technique of Rambourg et al. (1969).

Animals