Acetylcholinesterase from Wistar rat brain.

Acetylcholinesterase (E.C.3.1.1.7) was partially purified from rat brains stored in toluene. Extraction was performed using buffers containing non-ionic tensoactive detergents. Some properties of the enzyme were affected by the use of different activity measurement methods, such as the short-time radiometric or the long-time colorimetric method. There were two zones of maximum activity in the range pH 7.5-8.0 and 8.0-8.6, respectively. There seems to be a histidine residue in the enzyme that participates in the catalytic process. Thermal denuration presented first order kinetics and different thermodynamic parameters were obtained on using different incubation periods. On using the short-time activity measurement method there was activation at high substrate concentration, but with the long time method there was a marked inhibition produced by excess of substrate. However, if the enzyme was extracted from fresh rat brain, toluene untreated, these differences dissapeared. Gel filtration and disc electrophoresis showed the presence of multiple and interconvertible forms of the enzyme.     

Intestinal lymphoid tissue changes in the cortisone-treated Wistar rat

This paper continues the previous investigation of the Department on the lymphoid tissue of central and peripheral lymphoid organs under different experimental conditions. The morphological reactional modalities of the intestinal lymphoid tissue in the male Wistar rat were followed up under endocrine imbalance conditions following cortisone administration. Seven days after administration cortisone induced a hyperplasia of the intestinal lymphoid tissue in parallel with a depletion of the lymph node parenchyma and a hypercellularity of bone marrow. After a 6-week postcortisone interval, the lymphoid tissue showed changes corresponding to a cellular depletion in parallel with the restoration of the lymph node parenchyma and a normocellular bone marrow.     

Measurement of whole blood phagocyte chemiluminescence in the Wistar rat

The factors influencing the rat whole blood chemiluminescence (CL): concentrations of blood, luminol, zymosan or opsonized zymosan, volume of the reaction mixture, storage time of blood samples and the presence of anticoagulants were evaluated. The CL micromethod described provides a fast and sensitive tool for the determination of metabolic activity of phagocytes in the microlitre range of rat whole blood. © 1997 John Wiley & Sons, Ltd.     

Intra uterine survival and growth of Wistar and Wistar x Brown Norway rat embryos

Embryos of the Wistar strain and its F(1) cross (Wistar females mated with Brown Norway males) of rats were transferred nonsurgically to 48 Wistar, 17 F(1) cross and 20 Wistar-Imamichi recipients. The two types of embryos were transferred together to each recipient to compare the viability of the embryos. Pregnancy rate was 78.8% (67 85 ). The survival rate of fetuses to term was 11.5% (20 174 ) and 25.1% (42 168 ) for the Wistar and F(1) embryos, respectively. Placental weight differed significantly (P<0.05) between embryo types and among recipient types while fetus weight differed (P<0.01) only among recipient types, with a significant interaction between recipient and embryo types (P<0.01). It was concluded that the F(1) embryos (Wistar x Brown Norway) were twice as viable as Wistar embryos under the conditions provided.     

A supernumerary forelimb in a Wistar rat

A fifth limb, quite independent of the others, was found in a pup born in our colony of Wistar rats. The malformation is described.     

Ribavirin-induced sperm shape abnormalities in Wistar rat

Ribavirin (1-β-d-ribofuranosyl-1,2,4, triazole-3 carboxamide) is a broad-spectrum antiviral drug. This study was aimed to investigate the mutagenicity of ribavirin on germ cells by employing sperm morphology assay. Male Wistar rats were treated with water, cyclophosphamide (CP) 40 mg/kg, and ribavirin 20, 100 and 200 mg/kg (i.p.) for 5 consecutive days at intervals of 24 h. Following the last exposure, at 14, 28, 35, 42 and 70 days, the epididymal sperm smears were obtained and stained according to the standard procedure. One thousand sperms per animal were classified into normal and different abnormal types. Both CP and ribavirin-induced anomalies of head and tail of sperm except at 70 days. In CP groups, maximum incidence was observed at 28, 35 and 42 days. Ribavirin 20 mg/kg induced maximum incidence at 14 and 42 days, 100 mg/kg at 28 and 42 days and 200 mg/kg at 28-42 days. These results show that ribavirin is mutagenic to rat germ cells in a transient fashion.     

Immuno-corticotropin interactions in a nociceptive environment in the Wistar rat

In pregnant rats, oral administration of ammonium nitrate, stress with ether and antigenic stimulation were found to induce immune variations, hormonal changes and evince the organism's capacities of detoxification. An activation of the immune system and immunosuppression have been recorded respectively during xenobiotics administration and antigenic stimulation, and during stress. Corticotrophe response occurred on the 6th day of gestation and was more pronounced from the 12th day onwards in animals receiving ammonium nitrate. At the end of the gestation period, however, the corticotrophe response became stable in treated animals. Ammonium nitrate administration seemed to drive a major toxicity effect, clearly observed through increased levels of methemoglobine and coincided with a significant decrease in the level of glutathione, confirming a mechanism of detoxification.     

A Tyrosinase missense mutation causes albinism in the Wistar rat

Tyrosinase serves as a key enzyme in the synthesis of melanin. In humans mutations in the TYR gene are associated with type 1 oculocutaneous albinism (OCA1) that leads to reduced or absent pigmentation of skin, hair and eye. Various mutations causing OCA in man, mouse, rabbit and cattle have been identified throughout the Tyrosinase gene including nonsense, missense, frameshift and splice site alterations. Here we report a missense substitution at codon R299H in exon 2 of the Tyr gene in the albino Wistar rat. As this very exchange has already been described in OCA patients, our findings reinforce the significance of this region for normal catalytic activity of tyrosinase protein.     

Ribavirin-induced sperm shape abnormalities in Wistar rat.

Ribavirin (1-beta-D-ribofuranosyl-1,2,4, triazole-3 carboxamide) is a broad-spectrum antiviral drug. This study was aimed to investigate the mutagenicity of ribavirin on germ cells by employing sperm morphology assay. Male Wistar rats were treated with water, cyclophosphamide (CP) 40 mg/kg, and ribavirin 20, 100 and 200 mg/kg (i.p.) for 5 consecutive days at intervals of 24h. Following the last exposure, at 14, 28, 35, 42 and 70 days, the epididymal sperm smears were obtained and stained according to the standard procedure. One thousand sperms per animal were classified into normal and different abnormal types. Both CP and ribavirin-induced anomalies of head and tail of sperm except at 70 days. In CP groups, maximum incidence was observed at 28, 35 and 42 days. Ribavirin 20 mg/kg induced maximum incidence at 14 and 42 days, 100 mg/kg at 28 and 42 days and 200 mg/kg at 28-42 days. These results show that ribavirin is mutagenic to rat germ cells in a transient fashion.