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Biomedical subjects

I G Wright

Publications and source records attributed to I G Wright.

At least 55 records · Page 3Linked to original sources
PubMed1988

The effects of calcium channel blocking drugs on halothane initiation of malignant hyperthermia in MHS swine and on the established syndrome.

We have investigated in malignant hyperthermia susceptible swine in vivo the effects on halothane initiation of the MH syndrome and on the established syndrome of five calcium channel blocking drugs--nifedipine, nisoldipine, diltiazem, verapamil and flunarazine. Nifedipine alone caused attenuation of halothane-initiated malignant hyperthermia to the extent of blocking onset of the syndrome in 29% of animals for the 60 minute period of exposure. In the face of the established malignant hyperthermia syndrome, all the drugs tested were therapeutically completely ineffective.

Anesthesia, General↗
PubMed1988

Babesia bovis: studies of parameters influencing microvascular stasis of infected erythrocytes.

Bovine erythrocytes infected with Babesia bovis were analysed for parameter changes known to influence rigidity and deformability of erythrocytes. Marked increases in malonyldialdehyde were detected indicating that lipid peroxidation occurs during infection. Consequently, increases in membrane lipid, methaemoglobin and membrane-bound haemoglobin were detected. Conversely, decreases in the antioxidant vitamin E and decreases in sialic acid were also detected. The cumulative effect of these changes would be to increase erythrocyte rigidity and decrease deformability thus contributing to the microvascular stasis characteristic of acute B bovis infection.

Animals↗
PubMed1987

Babesia bovis: vaccination studies with three groups of high molecular weight antigens from lysate of infected erythrocytes.

A void volume fraction and fractions of mean sizes 800 kdalton and 300 kdalton were isolated by gel filtration from lysate of bovine erythrocytes infected with Babesia bovis. All fractions had good serological activity, as assayed by ELISA and IFA. Groups of four splenectomized calves were vaccinated with each fraction and then challenged, together with groups of four control calves, with a homologous strain of B. bovis. The group vaccinated with the 300 kdalton fraction showed some protection, as indicated by delayed and significantly lower parasitaemias and by a 75% survival in the group. In contrast, all animals in the relevant control group died from infection. No evident protection was obtained with the other two fractions.

Animals↗
PubMed1987

An enzyme linked immunosorbent assay to diagnose Babesia bovis infection in cattle.

The optimum gel filtration fraction from lysate of Babesia bovis infected erythrocytes was determined for use as an antigen in an ELISA to diagnose B. bovis infection in cattle. Of four enzyme labels tested, horseradish peroxidase was the most suitable. The assay is both sensitive and specific in detecting antibody for 2-4 years after a single infection. False positive reactions were obtained only with some sera from some Anaplasma marginale infected cattle.

Animals↗
PubMed1987

Babesia bovis--analysis and vaccination trial with the cryoprecipitable immune complex.

Plasma samples from cattle recovering from acute Babesia bovis infection contain cryoprecipitable immune complexes (IC). Production of bovine and rabbit antisera to IC and subsequent serological assays indicated IC contained antigens of both babesial and erythrocytic origin. Vaccination of naive cattle with IC produced low titred antibody to B. bovis but the vaccinates did not survive challenge with a heterologous strain of B. bovis.

Animals↗
PubMed1987

Protection of Babesia bigemina-immune animals against subsequent challenge with virulent Babesia bovis.

Two groups of cattle, one previously exposed to Babesia bigemina and one not, were challenged with Babesia bovis. The group previously infected with Babesia bigemina was only mildly affected upon challenge with B. bovis, whereas four of five of the other group were severely affected. Immunoblotting studies performed in both homologous and heterologous systems showed that there were polypeptides of similar molecular weight in both species, but species-specific polypeptides were demonstrated only in B. bovis by the homologous B. bovis reaction. B. bovis antisera reacted avidly with B. bigemina-infected erythrocytes in fluorescent-antibody assays. In contrast, B. bigemina antisera did not cross-react with B. bovis-infected erythrocytes. Two groups of splenectomized calves were immunized with an enriched antigen fraction of B. bigemina. A third group was immunized by infection with B. bigemina and treatment with a drug. One of the groups of calves immunized with the antigenic fraction of B. bigemina, the group immunized by infection with B. bigemina, and a control group were challenged with B. bovis. All control calves died, whereas 50% of the calves immunized by infection with B. bigemina and 75% of the animals immunized with the B. bigemina antigen survived. The second group immunized with the B. bigemina antigen and a control group were challenged with B. bigemina. All control animals died by day 6, whereas 50% of the vaccinates survived, the deaths occurring on days 8 and 11. The nature of the probable protective mechanism is discussed.

Animals↗
PubMed1986

Babesia bovis: vaccination trial with a dominant immunodiffusion antigen in splenectomised calves.

The dominant immunodiffusion antigen of Babesia bovis was prepared from the lysate of infected erythrocytes by cation exchange chromatography, gel filtration and preparative native acrylamide electrophoresis. It was seemingly free of other babesial antigens and tested as a vaccine. In vaccinated calves, compared to controls, there was a delay in parasitaemia and at times a statistically significant difference in parasite numbers. However, the vaccinates showed little difference in pathophysiological parameters or survival rates from the controls. It was concluded that serodominance cannot necessarily be correlated with protection.

Animals↗
PubMed1985

Hypo-osmolar intravascular volume overload during anaesthesia for transurethral prostatectomy. A report of 2 cases.

Two cases are reported in which absorption of surgical irrigant into the vascular system during transurethral resection of the prostate gland (TUR) resulted in life-threatening complications due to hypo-osmolar volume overload (also known as water intoxication or the TUR syndrome). Manifestations common to both cases were haemolysis of red cells, cardiac arrhythmias, a drop in the serum sodium level, and an elevated central venous pressure. In addition, one patient developed acute pulmonary oedema and the other hypokalaemia, confusion and visual disturbances due to cerebral oedema. Water as an irrigant for TUR should be superseded by glycine 1,5%, which is safer.

Aged↗
PubMed1985

Protective vaccination against virulent Babesia bovis with a low-molecular-weight antigen.

A Babesia bovis low-molecular-weight antigen was purified from crude material by using affinity adsorption techniques first with a mouse monoclonal antibody and then by adsorption with normal bovine sera. The antigen was then further purified by gradient gel electrophoresis. Analysis by Western transfer revealed only one antigen band, with an apparent molecular mass of 29 kilodaltons. A band (12 by 0.3 by 0.6 cm) corresponding to this antigen was excised from the acrylamide gel and injected twice 4 weeks apart, together with 2.5 ml of Freund complete adjuvant, into nine nonsplenectomized adult cattle. The vaccinated cattle and five susceptible control animals were challenged with a virulent homologous strain 4 weeks after the second vaccination. None of the vaccinated animals was clinically affected, whereas three of five controls were severely affected. Control animals had significantly greater declines in packed cell volume and greater rises in temperature and parasitaemias than vaccinated animals.

Animals↗
PubMed1984

Babesia bovis: vaccination of cattle against heterologous challenge with fractions of lysate from infected erythrocytes.

The distilled water lysate of erythrocytes infected with Babesia bovis was separated by gel filtration on Sephadex G200. The void volume fraction or a pool of retained fractions which had immunodiffusion activity were injected into two groups of five cattle. These were challenged 2 weeks after the final vaccination with a heterologous strain of B. bovis. A control group of five cattle was similarly challenged. Two of the five control animals died from the challenge, whereas none of the vaccinated animals died. There were significant differences in parasitaemia and pathophysiological parameters between the vaccinated groups and the control group.

Animals↗