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Biomedical subjects

S Rehm

Publications and source records attributed to S Rehm.

At least 91 records · Page 5Linked to original sources
PubMed1984

A comparison of life-span and spontaneous tumor incidence of male and female Han:WIST virgin and retired breeder rats.

In a long-term study, the life-expectancy of 320 female virgin Han:WIST rats was significantly lower than that of 320 male virgins, whereas no major differences existed in a successive study with retired breeders (296 females and 252 males) of the same stock. Within the sexes, the female retired breeders lived on average longer than the virgins, whereas the male retired breeders had a higher mortality between the 33rd and 36th month than their virgin counterparts. Differences in life-expectancy were mainly due to varying incidences of uterine adenocarcinomas in the females and an adverse development of pituitary gland tumors in the males. A sexual difference was found in both groups for tumors of the pituitary gland, the islet cells of the pancreas, mammary gland, subcutis and mesenteric lymph nodes. A possible hormonal influence on tumorigenesis is discussed.

Age Factors↗
PubMed1984

Spontaneous ovarian tumors in Han:NMRI mice: histologic classification, incidence, and influence of food restriction.

In a life-span study with female Han:NMRI virgin mice (300 of a fat subline, 300 of a lean subline, and 300 controls), a total of 424 mice developed 673 ovarian tumors. Half of the mice in each group were fed ad libitum, and for the other half food was restricted. Most prevalent were tubular adenomas followed by granulosa and Sertoli cell tumors. Altogether, 42 neoplasms were classified as tubular adenocarcinomas, and 21, as luteomas . The general incidence of tumors increased sharply beyond the 18th month of age. Granulosa cell tumors arose relatively early, and tubular adenocarcinomas occurred very late in life. The occurrence of ovarian tumors depended mainly on life expectancy. All animals subjected to food restriction lived longer and developed more ovarian neoplasms than those fed ad libitum.

Aging↗
PubMed1984

Biochemical characterization of endogenous carbohydrate-binding proteins from spontaneous murine rhabdomyosarcoma, mammary adenocarcinoma, and ovarian teratoma.

Three entirely different tumor types were investigated biochemically for the presence and characteristics of endogenous carbohydrate-binding proteins in an inbred Brown Norway rat, an outbred Sprague-Dawley rat, and an outbred Han:NMRI mouse. The patterns under investigation included specificities for alpha- and beta-galactosyl, alpha-mannosyl, and alpha-fucosyl moieties, respectively, and specificities for heparin, analyzed by affinity chromatography on resins with immobilized sugars or glycoproteins and polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The patterns were divided into categories according to dependence of the binding activity on the presence of Ca2+ and dependence on extraction conditions. Rhabdomyosarcoma revealed only Ca2+-independent activities, i.e., activities with specificity for beta-galactosides at a molecular weight of 12,000, with specificity for alpha-galactosides at molecular weights of 29,000, 43,000, and 45,000, with specificity for heparin at molecular weights of 13,000 and 16,000, and with specificities for mannose and fucose at molecular weights ranging from 62,000 to 70,000. For the spontaneous mammary adenocarcinoma the pattern was entirely different and more diverse, including species with the Ca2+ requirement. Extracts with the use of 0.2 M NaCl (salt) and 2% Triton X-100 (detergent) from teratoma contained at least nine different carbohydrate-binding proteins. The only similarities between the pattern of endogenous carbohydrate-binding proteins from teratoma and from mammary adenocarcinoma were beta-galactoside-binding proteins, one with a Ca2+ requirement and one without a Ca2+ requirement, and the heparin-binding proteins. These heparin-binding proteins were the only types of carbohydrate-binding proteins common to all three tumor types. The analysis indicates that certain bands represented newly identified proteins capable of binding to galactose-, mannose- or fucose-containing glycoconjugates, respectively. When assayed with rabbit erythrocytes, the different fractions showed agglutination activity. They can thus be termed "endogenous lectins." The use of endogenous lectin patterns as potential diagnostic markers in addition to the corresponding changes in the glycoconjugate composition is proposed.

Adenocarcinoma↗
PubMed1982

Organ pattern of age-related changes in the aminoacyl-tRNA synthetase activities of the mouse.

The specific activities of 17 aminoacyl-tRNA synthetases from liver, lung, heart, spleen, kidney, small intestine and skeletal muscle of young (2 months) and aged (39 months) female Han:NMRI mice were determined under standard conditions of sample preparation and assay. The average reduction of total activity during ageing is 70% for liver, 50% for lung and spleen, nearly 40% for heart and kidney and nearly 20% for intestine and skeletal muscle. Detailed comparison reveals no general, but an organ-specific pattern. Aminoacyl-tRNA synthetases were, furthermore, found to be ribosome-associated in higher proportions in liver tissue from aged mice.

Aging↗
PubMed1982

Diagnosis of Mycoplasma pulmonis infection of rats by an indirect immunofluorescence test compared with 4 other diagnostic methods.

Efficiency of indirect immunofluorescence microscopy (IFM) for detection of M. pulmonis antibody (IgG) in rats was compared with results of enzyme-linked immunosorbent assay (ELISA), complement fixation (CF), cultural isolation and histopathology. IFM was carried out on M. pulmonis infected BHK-21 cells grown on cover slips or multitest slides. After acetone fixation these antigen carriers could be stored at -20 degrees C for several months so that serological tests could be done at any time and completed within 2 h. The IFM was strain specific and the sensitivity of the test was comparable with that of the ELISA, whereas the CF-test proved to be very insensitive. For routine monitoring, only in cases of fresh infections should time consuming cultural procedures be preferred to serological tests. Chronic disease stages were readily detected by histological examination.

Animals↗
PubMed1982

A new rat mutant with defective overhairs and spongy degeneration of the central nervous system: clinical and pathologic studies.

A new spontaneous autosomal recessive mutation with a nervous disorder and a hair anomaly occurred in a colony of Sprague Dawley rats. The animals developed a generalized body tremor at about 15 days of age, and with increasing age a progressive flaccid paresis occurred. Light microscopy revealed spongy changes in the central nervous system. The mutant was designated zitter rat (zi).

Animals↗
PubMed1981

Uncommon frequency of adenocarcinomas of the uterus in virgin Han:Wistar rats.

In a longevity study on 320 male and 320 female specified-pathogen-free Han:Wistar rats, 119 (39.0%) of 305 females evaluated developed spontaneous metastatic uterine adenocarcinomas. These tumors caused a great difference between the mortality rates of males and females. Thirty five percent of the females died of adenocarcinomas of the uterus. The tumors began as small nodules in one or both horns near the bifurcation. Large tumors extended through the uterine wall and produced wide-spread transcoelomic metastases. Early lesions were well-differentiated adenocarcinomas but advanced tumors were more poorly differentiated.

Adenocarcinoma↗
PubMedDate not supplied

Tissue susceptibility factors in cadmium carcinogenesis. Correlation between cadmium-induction of prostatic tumors in rats and an apparent deficiency of metallothionein.

Recently, in two separate studies we have observed cadmium (Cd)-induction of prostatic tumors (PT) in rats. Cd (sc or im) at doses nontoxic to the testes markedly increased PT formation (2.5 mumols/kg, sc, 8 PT/29 exposed, 28%; 30 mumols/kg, im, 11/26, 42%; control 14/127, 11%). The administration of zinc (Zn; 1 mmol/kg, sc, at -6, 0 and +18 h) to prevent testicular toxicity and tumors from Cd (30 mumols/kg, sc, 0 h) also resulted in an elevated incidence of PT (8/27, 30%). The nature of the metal-binding proteins in the prostate has not been defined, although metallothionein (MT), a low Mr Cd-binding protein that confers tolerance to Cd, is deficient in other target tissues of Cd carcinogenesis, such as the rat testes. Using a technique that extracts MT from liver, a low-Mr Cd-binding protein was extracted from both ventral (VP) and dorsal prostate (DP) and isolated by gel filtration. In contrast to the two forms of rat MT, reverse phase HPLC of VP and DP extract eluted 1 and 5 forms, respectively. The amino acid compositions of the VP and DP proteins were quite distinct from MT, with much less cys than MT and the presence of residues not found in MT (leu, tyr, phe). Thus Cd-induction of PT appears to be dependent on functional testes and, as is the case with Cd-induced testicular formation, appears to be associated with a deficiency of MT.

Animals↗
PubMedDate not supplied

Genetic and environmental influences on lifespan and diseases in Han:Wistar rats.

In a longevity study with SPF rats of the Han:Wistar outbred stock, 320 virgin males and 320 virgin females of marked littermates were maintained in a barrier-type animal house under highly standardized conditions from weaning until their natural end of life. Diseased and dead animals were sectioned and examined using histological, bacteriological and virological methods. The mortality of the rats is low up to the 18th month of life. Thereafter the mortality graph inclines steadily. The course of the graph is determined by very few diseases only, such as pituitary adenomas in both sexes, adenocarcinomas of the uterine glands in the females, and in the third and fourth year nephropathies in the males. Because of the high number of adenocarcinomas of the uterine glands the median life expectancy is between 30 and 33 months for the females, somewhat lower than between the 33rd and the 36th months for the males. The disease spectrum consists generally of tumor lesions, but out of the large tumor spectrum only single alterations exceed the 5% border. As shown by analysis of variance and estimation of the heritability coefficients (h2), mortality and the most important tumorous lesions underlie high genetic effects. The cage environments are found to have no influence upon mortality and diseases. Under the given standardized environmental conditions, the present results can be looked upon--because of the strong genetic effects on mortality and diseases - to be representative for correspondingly selected populations of future generations of the Han:Wistar stock.

Animals↗
PubMedDate not supplied

Spontaneous testicular lesions in purpose-bred beagle dogs.

Spontaneous testicular lesions were assessed in 50 control purpose-bred male beagle dogs. They were selected from 13 toxicology studies conducted over the period 1988-1999. Age of the dogs at study termination varied from 8-20 months with an average age of 13 months. Regardless of age, the most significant finding was bilateral segmental hypospermatogenesis in 15/50 (30%) of the dogs. Cross sections of tubules with hypospermatogenesis were distributed randomly throughout the testes and were characterized by reduced proportions of germ cells, tubular shrinkage, and Sertoli cell prominence. These changes were occasionally associated with giant cells, with cellular debris, and in 6/15 (40%) with atrophic tubules devoid of germ cells, indicating a degenerative process. Focal subcapsular tubular atrophy or hypoplasia (tubules lined by Sertoli cells only) was also found in 9/35 (26%) of dogs without hypospermatogenesis. Inhibited spermiation with retention of mature sperm in tubules was seen in 6/50 dogs, 3 of which also showed hypospermatogenesis. Other findings of high incidence but low prevalence included tubules with multinucleated giant cells, swollen spermatocytes, or apoptotic germ cells. These latter changes are probably a constituent of normal spermatogenesis. In conclusion, about 30% of control beagle dogs show segmental hypospermatogenesis, which may be associated with degenerative changes, and an additional 18% of the dogs exhibit focal tubular atrophy/hypoplasia in otherwise normal testes. These changes have to be distinguished from compound-related toxic effects.

Animals↗