Spontaneous rhabdomyosarcoma in a young Sprague-Dawley rat

An eight-week-old male Sprague-Dawley (SD) rat showed signs of emaciation, and masses were found in the subcutis around the cervical and thoracic regions. At necropsy, a multilobular mass, 2.2 x 1.8 x 2.0 cm in size, had grown from the left neck into the thoracic cavity. On a cutting surface, masses were firm and whitish to tan, with necrotic and hemorrhagic plaques. Microscopically, masses were composed of multiple nodules of tumor cells that were incompletely encapsulated with fibrous connective tissue. The tumor cells exhibited varied forms, from spindle to globoid shapes with minimal to abundant eosinophilic cytoplasm, and appeared as large, multinucleated cells; many of the tumor cells were vacuolated. Histochemistry results revealed that tumor cells exhibited some cross-striation in the cytoplasm using PTAH staining. There were some multinuclear tumor cells with vacuoles located around the nuclei, and these vacuoles showed reddish staining by the periodic acid Schiff (PAS) method. Immunohistochemical staining also expressed intense granular cytoplasmic staining for desmin and myoglobin, with highly positive staining for PCNA, whereas alpha-smooth muscle actin (alpha-SMA) was negative. Based on the pathology results, a spontaneous rhabdomyosarcoma with pleomorphic type was diagnosed in a young SD rat.     

A liver schwannoma observed in a female Sprague-Dawley rat treated with MNU

BackgroundSchwannoma is a tumor of the nervous system composed by Schwann cells. It can occur naturally in several tissues of the body in both humans and animals. Diaphragmatic hernia can be congenital or acquired and is defined as a protrusion of abdominal viscera into the thoracic cavity.Materials and methodsThe animal was a female rat from an experiment of mammary tumor chemically induced. It was injected with N-methyl-N-nitrosourea (MNU) and died spontaneously at 22 weeks of age.ResultsThe animal had a diaphragmatic hernia and a hemorrhagic and multicystic mass in the liver herniated lobule. Microscopically the liver displayed a well circumscribed mass that was a tumor with hemorrhagic areas, necrosis and Antoni A and Antoni B patterns. It also displayed occasional positivity to vimentin and diffuse positivity to S-100 and NSE.ConclusionThe tumor was a schwannoma with the origin in the Glisson's capsule.     

Leiomyoma of the iris in a Sprague-Dawley rat

A leiomyoma of the iris was composed of bundles of spindle-shaped cells with abundant myoglial fibres and represents the first observation of this rare tumour in a rat.     

Spontaneous neoplastic lesions in Harlan Sprague-Dawley rats.

In a 24-months study, the spontaneous tumour spectrum of the Hsd:Sprague-Dawley stock was examined. Pituitary gland tumours were found in 20% of the males and 39% of the females. This relatively low incidence, compared to other SPRD stocks, had little effect on the survival of females (50%), due to the high incidence (76%) of mammary gland tumours (predominantly fibroadenomas) that resulted in unscheduled sacrifices of many females. Other common neoplasms in Hsd:Sprague-Dawley rats were benign medullary tumours (27% in males, 11% in females), C-cell adenomas (23% in males, 28% in females), and endometrial stromal polyps (22% in females).     

Lipid peroxidation in a focus of hyperactivity in the rat cerebral cortex

It is shown that lipid peroxidation (LPO) can participate in the mechanism of development of paroxysmal activity in the rat cerebral cortex. The appearance of epileptic activity as a result of application of the sodium salt of penicillin to the surface of the sensomotor cortex led to a sharp rise in LPO products in the fraction of unpurified synaptosomes isolated from a focus of hyperactivity. Preliminary injection of the antioxidant -tocopherol into rats abolished the LPO activation effect and considerably reduced the number of paroxysms recorded on the electrocorticogram during existence of the focus.Laboratory of General Pathology of the Nervous System, Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 89, No. 1, pp. 14–16, January, 1980.     

Phases in the development of a penicillin epileptiform focus in rat neocortex

Somatosensory evoked potentials and potentials evoked by direct cortical stimulation were recorded from layer IV of the somatosensory area of the cerebral cortex in urethane anaesthetised rats. Penicillin was expelled electrophoretically from the tip of a drug-filled micropipette at constant rates into layer IV. Small fluxes of penicillin (with electrophoretic currents of -50 to -90 nA) resulted in the appearance, after a delay of 1–2 min, of an enhancement of amplitude in the voltage of both types of evoked potential, unaccompanied by any prolongation of the waveform or spontaneous focal epileptiform discharges. The amplitude of the enhanced evoked potential exhibited a strength-response curve which was a scaled-up version of the curve before penicillin, the scaling factor reflecting the enhancement of amplitude. As the interval between a pair of stimuli was increased, the magnitude of the response to the second stimulus recovered, following a time course similar to that before penicillin. With larger fluxes of penicillin (with electrophoretic currents of -250 to -1000 nA) the amplitude of evoked potentials rose more rapidly and to a higher level; as the concentration of penicillin rose, this enhancement of amplitude led into a second phase, in which there was additionally an increase in the duration of the evoked potentials and the appearance of spontaneous epileptiform discharges. The evoked potentials in this situation showed physiological properties different from those before penicillin application. The strength-response curve exhibited a discontinuity, indicating the evoked potential to be the sum of a physiological response and an epileptiform discharge, the former being graded with stimulus strength and the latter being all or none. With paired stimuli, the response to the test stimulus was profoundly depressed for long conditioning-test intervals by comparison with the relatively rapid recovery exhibited by normal brain. When a cuboid of cortex measuring 0.6 mm² or less was partially isolated subpially by incisions extending through the upper half of the cortical mantle, all the features of hyperexcitability produced by penicillin in intact cortex were blocked. This shows that even the simple enhancement of evoked potentials, which is the earliest indicator of hypersynchronous activity, differs from an exaggeration of normal evoked activity in requiring a larger community of neurones with their horizontal intracortical connections intact.     

Spontaneous osteogenic sarcoma in the rat

A spontaneous osteogenic sarcoma of the spinal column (tail, sacrum and lumbar regions) with metastases to the lungs, kidneys and right ovary were found in a 15-month-old BHE rat. The literature on spontaneous osteogenic sarcoma in rats indicates that this tumour is rare (0.22 per cent), occurs in several strains and has no sex, age or site predilections; non-metastatic cases are more common than metastatic ones.     

Morphologic classification and incidence of hematopoietic neoplasms in the Sprague-Dawley rat

Hematopoietic and related neoplasms were morphologically studied in a total of 1,765 male and 1,765 female Sprague-Dawley rats from 6 chronic toxicity studies conducted at a large toxicology testing laboratory. The most common types of lymphoid neoplasms seen included the lymphoblastic lymphoma (0.65%) and the large granular lymphocyte lymphoma (LGL, Fischer or mononuclear cell leukemia) (0.60%). The most common type of nonlymphoid neoplasm with morphologic features similar to lymphoid tumors was histiocytic sarcoma (1.1%). A small number of cases of myelogenous leukemia were also seen. Additional work is needed in the classification of hematopoietic neoplasms in rats including refined immunomorphological studies.     

Spontaneous spinal subdural hematoma in a young adult with hemophilia.

Spontaneous spinal subdural hemorrhage is a rare clinical problem that usually manifests with a sudden onset of pain and paralysis. This article reports on an 18-year-old male with hemophilia A and cerebral palsy, who experienced a several month history of transient back, hip, and leg pain accompanied by gait difficulties that ultimately culminated in a more striking episode of lower extremity weakness, irritability, and diffuse pain involving the neck, back, and legs. In the absence of any clinical or radiographic evidence of hemarthrosis, osteomyelitis, or intracranial hemorrhage, imaging of the spine disclosed a large, apparently multicompartmentalized intraspinal lesion, consistent with old hemorrhage. This extended from the thoracic to the sacral region, with the largest extent at the lumbosacral junction. Following correction of factor VIII levels, surgical exploration was undertaken and demonstrated liquefied blood within the subdural space without violation of the underlying arachnoid. Because the chronic subdural blood flowed quite easily through the dural opening by simply angling the operating table, a limited exposure was required to achieve a substantial evacuation of the clot. This case calls attention to the often protean manifestations of this process, the potential for a chronic course to the clinical symptoms, and the possibility of achieving substantial clot evacuation and clinical recovery with a limited operative approach.     

Spontaneous leiomyosarcoma arising from the ethmoid turbinate of a rat

Spontaneous leiomyosarcoma arising from the left ethmoid turbinate was observed microscopically in an 83-week-old male F344 rat. The tumor cells showed smooth-muscle differentiation with prominent nuclear pleomorphism and a small number of mitotic figures. The tumor cells were also immunohistochemically positive for smooth-muscle actin. The tumor protruded slightly into the nasal cavity and invaded the surrounding tissues. The present article is the first case of spontaneous leiomyosarcoma in the rat nasal cavity.     

生物人工肝的临床应用及其生物成分研究中的几个热点问题

生物型人工肝最早于1987年应用于临床,目前临床可应用的生物成分仍然来源于肝细胞(系).本文就临床应用现状、肝细胞来源、组织工程三个方面进行了综述.     

Spontaneous brain and spinal cord/nerve neoplasms in aged Sprague-Dawley rats.

Primary malignant neoplasms of the brain and spinal cord occurred in 20/718 male (2.8%) and in 13/717 female (1.8%) Crl:CD Br strain Sprague-Dawley rats. Of 33 neoplasms, 30 were found in brain while 3 were in the spinal cord. In males and females, the most common brain neoplasm was astrocytoma (13 males, 9 females). Other neoplasms, granular cell tumor (1 male), mixed glioma (2 males, 1 female), reticulosis (1 male, 2 females), and oligodendroglioma (2 males), were especially uncommon. Spinal cord neoplasms included 2 schwannomas (1 male, 1 female) and an astrocytoma (1 male). The overall brain neoplasm incidence was similar for males (2.8%) compared to data compiled for this strain, and there was a 2-fold increase for females (1.8% vs 0.9%) compared to available incidence data.     

Spontaneous glomerular sclerosis in aging Sprague-Dawley rats. II. Ultrastructural studies.

Increased protein filtration and work overload have been proposed to account for the development of glomerular sclerosis in old rats. Sprague-Dawley rat kidneys were examined ultrastructurally from birth through 24 months of age to further delineate pathogenetic factors. There was progressive thickening of all basement membranes with lamination, intramembranous pseudolinear deposits, and degeneration. The glomerular basement membrane (GBM) was 1300 A at birth and increased to 4800 A by 24 months of age. GBM thickening correlated very closely with age (r = 0.90, P less than 0.001), correlated roughly with mesangial sclerosis, but did not correlate at all with proteinuria. Obliteration of podocytes and degenerative changes in the cytoplasm occurred in all cell types and was present in both proteinuric and nonproteinuric rats. These findings suggest that the lesion of spontaneous glomerular sclerosis of aging rats results not from proteinuria but from the natural process of abiotrophic involution. Further, this lesion is but a more obvious indicator of the alterations occurring simultaneously in other portions of the kidney.     

Distribution of PDE8A in the nervous system of the Sprague-Dawley rat

Phosphodiesterases (PDEs) are essential regulators of cyclic nucleotide signaling. Little is known of the distribution and function of the cyclic adenosine monophosphate (cAMP) hydrolyzing PDE8A family.Employing immunohistochemistry and Western blots this study maps the distribution of PDE8A in the brain of adult male Sprague-Dawley rats and in the trigeminal ganglion.PDE8A was confined to neuronal perikaryal cytoplasm and to processes extending from those perikarya. The neurons exhibiting PDE8A-immunoreactivity were widely distributed in the forebrain, brain stem, and cerebellum. Strongly immunoreactive neurons were located in the olfactory bulb, the septal area, zona incerta, and reticular nucleus of the thalamus. Less immunoreactivity was seen in the hippocampus and cerebral cortex. Intense staining was detected in both the substantia nigra and the sensory trigeminal nucleus. In cerebellum PDE8A immunoreactivity was located not only in the Purkinje cells, but also in the granular cells as well as the parallel fibres in the molecular layer. PDE8A immunoreactivity was represented in the epithelial lining of the choroids plexus, the dura mater, and the neurons of the trigeminal ganglion.The localization of the cAMP degrading PDE8A may indicate a role for PDE8A in cAMP signaling related to pain transmission, motor function, cognition and olfaction.