Purification and characterization of histamine dehydrogenase from Nocardioides simplex IFO 12069.

Histamine dehydrogenase from Nocardioides simplex IFO 12069 was purified to homogeneity. The enzyme had a molecular mass of 170 kDa and was suggested to be a dimer of subunits that had a molecular mass of 84 kDa. The enzyme showed highest activity toward histamine and produced ammonia in its oxidative deamination to imidazole acetaldehyde. The K(m) and V(max) values for histamine were 0.075 mM and 4.76 micromol min(-1) mg(-1), respectively. The enzyme was sensitive to the carbonyl reagent iproniazid and a structurally similar compound, tryptophan. The enzyme showed absorption maxima at 442 and 280 nm. Reduction with histamine under anaerobic conditions resulted in a different absorption maximum at 360 nm instead of 442 nm. The enzyme was most active at pH 8.5 in Tris-HCl buffer and most stable at pH 7.0 in potassium phosphate buffer. The E(1%) value of the enzyme was 8.6 at 280 nm.

Studies on the possiblilty of production of immunity against schistosomiasis in experimental animals.

In the present work antigenization with somatic and metabolic antigens of adult Schistosoma mansoni worms, their cercariae or eggs has been tried. The study of the immunoglobulin patterns in infected and vaccinated non infected mice showed increase in IgG in all animals, increase in IgM only in the infected and IgA was frequently increased in mice that received metabolic or egg antigens. As regards the degree of resistance of vaccinated animals to S. mansoni infection, 2 groups gave prominent results. 1st the group vaccinated with Schistosoma mansonmetabolic worm antigen in which we got: -- Reduction in the worm load. -- Delayed ovulation and reduction in the number of ova/24 hr stools and/g of liver tissue. -- The histopathological picture of the liver was the best. 2nd the group vaccinated with egg antigen: Although it showed delayed ovulation and reduction in the ova count per 4 hr stools and/g liver tissue, yet the histopathological picture was the worst showing the largest granulomata.

Leucine aminopeptidase, Significance of serum elevation in bilharziasis.

Leucine aminopeptidase (LAP) activity and creatinine concentration was estimated in serum of twenty five normal adult subjects, twenty four cases with active urinary bilharziasis, eleven cases with active intestinal bilharziasis, ten cases with mixed bilharzial infection (urinary and intestinal), fourteen bilharzial cases with clinical hepato-splenomegaly of bilharzial etiology, thirteen bilharzial cases with clinical hepatosplenomegaly and ascites, and twelve cases with cancer bladder of bilharzial etiology. Significant elevation in the serum enzyme level was found in all bilharzial cases which generally ran parallel to the course of the disease, being more marked in hepatosplenomegalic cases than in cases which showed no clinical signs of liver or spleen involvement. However, it was observed that the enzyme level was lower ascitic than in nonascitic cases. For serum creatinine concentration, no significant variation from normal value was observed in the group of patients with active urinary, active intestinal, mixed infections of bilharziasis and bilharzial hepatosplenomegalic cases. However, a very highly significant decrease in serum creatinine concentration was observed in the group of patients with bilharzial hepatosplenomegaly and ascites. Serum LAP activity and creatinine concentration in the group of patients with cancer bladder of bilharzial etiology showed no statistical variation from normal values.