Hypoplasia of one kidney in a Sprague-Dawley rat

Pathological examination of a 4-week-old male Sprague-Dawley rat revealed hypoplasia of the left kidney. Grossly, the left kidney exhibited hypoplasia associated with absence of the ureter on the same side. Histologically, components of the cortex and medulla were mingled in the tissue, and the glomeruli and convoluted tubules were scattered in disorder, and connective tissue proliferation was also observed. The papilla and pelvis could not be identified.     

Spontaneous teratoma in a Sprague-Dawley rat

An 6-week-old male Sprague-Dawley rat which had undergone no experimental treatment died from enlargement of the abdomen. At necropsy, a spherical mass measuring about 3 X 4cm in diameter was connected to the retroperitoneal region cross to the middorsal line of the body. The tumor was composed of skin, ganglion, striated and smooth muscle, cartilage, bone, pancreas, glands, lymph node, and fibrous and adipose tissue, and diagnosed as teratoma.     

Esterolytic and proteolytic enzymes of the rat adenohypophysis

Summary Characteristics of the hydrolysis of histochemical substrates 5-bromoindoxyl acetate, naphthyl acetate, proprionate, butyrate, caprylate, laurate, myristate, and palmitate, acetyl and butyryl thiocholhie, chloroacetyl and trifluoroacetyl -naphthylamide, benzoyl-arginine -naphthylamide and proteinase substrates human hemoglobin and glycyl-phenylalanine amide by the rat pituitary tissue homogenate and DEAE-cellulose chromatography fractions were determined.In DEAE-cellulose chromatography fractions four separate activities were found splitting short and long chain carboxylic esters. The activity hydrolysing most rapidly 5-bromoindoxyl acetate was resistant to E 600 and was identified as C esterase. Three of the remaining esterase activities were sensitive to E 600 and two of them hydrolysed more rapidly short-chain fatty acid esters while one preferred long-chain fatty acid esters as substrate.One peak of activity was identified as nonspecific cholinesterase on the basis of inhibition studies and hydrolysis of thiocholine substrates. Chloroacetyl -naphthylamide was hydrolysed minimally. Hydrolysis of trifluoroacetyl -naphthylamide was ascribed to E 600 resistant enzyme with pH-optimum at 8.3 hydrolysing also the thiocholine substrates and slowly long-chain fatty acid esters.Five different proteinases hydrolysing human hemoglobin were separated, three of them with pH-optima on the acid and two on the alkaline side of pH. The activities hydrolysing benzoyl-arginine naphthylamide were cysteine activated and had pH-optima around 5.3. None of the peaks of the proteinase activities appeared to coinside with the hydrolysis peaks of any of the histochemical ester substrates in the DEAE fractions.     

Dopamine-inhibited adenylate cyclase in female rat adenohypophysis

A dopamine-inhibited adenylate cyclase has been demonstrated in anterior pituitary gland of adult female rats, lactating and not lactating. This inhibitory effect was completely GTP dependent. In contrast, in the adenohypophysis of male rats, dopamine had no detectable effect on adenylate cyclase activity. In female rats the inhibition of the enzyme appears mediated by specific dopaminergic receptors: the effect of dopamine was mimicked by the dopaminergic agonists apomorphine and the ergot derivative CH 29–717, while norepinephrine was much less potent. On the other hand, the dopaminergic antagonists trifluoperazine and sulpiride competitively antagonized the dopamine inhibition of the adenylate cyclase. The possibility that the dopamine-inhibited enzyme is located in mammotrophs appears supported 1) by its observation in the female rat pituitary, which contains this type of cells in much larger proportion than the male gland (33–38% vs. < 5%); 2) by the pharmacological similarity between the dopaminergic receptors mediating the adenylate cyclase inhibition (this work) and those regulating prolactin release (which have been characterized in previous studies). The well known inhibition of prolactin release brought about by dopamine could therefore be mediated, at least in part, by a decrease in the intracellular level of cAMP.     

Pathology of sternal deformity in the Sprague-Dawley rat

Pathological examination of two 12-week-old male Sprague-Dawley rats revealed bending of the sternebrae. Grossly, the sternebrae distal to the third sternebra were bent towards the underside, and the episternal extremity was turned towards the head. Microscopically, the 4th sternebra was observed to have slipped behind the third sternebra, and fractures of the episternal cortex and slanting of the episternal cartilage were also observed.     

Predicted SAR in Sprague-Dawley rat as a function of permittivity values

Specific absorption rate (SAR) value is dependent on permittivity value. However, variability in the published permittivity values for human and animal tissue and the development of sophisticated 3-dimensional digital anatomical models to predict SAR values has resulted in the need to understand how model parameters (permittivity value) affect the predicted whole body and localized SAR values. In this paper, we establish the partial derivative of whole body SARs and localized SAR values (defined as SAR for individual organs with respect to a change in the permittivity values of all tissue types, as well as for those tissues with the most variable permittivity values. Variations in the published permittivity values may substantially influence whole body and localized SAR values, but only under special conditions. Orientation of the exposed object to the incident electromagnetic wave is one of the most crucial factors. Published 2001 Wiley-Liss, Inc.     

The ultrastructural characteristics of the corticotropic cells of the rat adenohypophysis

Ultrastructural characteristics of corticotropic cells have been studied on serial semithin and ultrathin sections of the hypophysis from intact rats by the immunofluorescence and electron microscopic methods. It is shown that the population of corticotropic cells is heterogeneous and consists of degranulated, moderate granulated, hypergranulated cells and transitional forms among them. Ultrastructurally corticotropic cells correspond to Siperstein-Nakayama's ACTH cells. Kurosumi-Kobayashi "corticotrophs" fail to react with the antiserum to ACTH, so they have not regard for its production.     

Castration cells in rat adenohypophysis after long-term alcohol consumption

Histological and ultrastructural changes of hypophyseal gonadotropic cells of rats which received a 15% solution of ethyl alcohol for 6 months were studied. Light microscopy revealed hyperplasia and hypertrophy of these cells; some contained a vacuole of varying size. Ultrastructural analysis showed that this vacuole originated from, and anastomosed with, dilated cisternae of the granulated endoplasmic reticulum. Vacuolated cells in the pituitary of alcoholized rats were identical with cells observed after surgical or chemical castration. The development of these alcohol-induced castration cells is achieved in four stages. The first stage was characterized by beginning hydropic degeneration and other still reversible alterations. Cells in the second and third stages seemed already irreversibly on their way to decay. The fourth stage was represented by typical signet-ring cells. Our results offer a morphological basis to the adoption of a biphasic effect of alcohol on gonadotropic secretion.