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Biomedical subjects

B Reiter

Publications and source records attributed to B Reiter.

At least 37 records · Page 2Linked to original sources
PubMed1980

The antibiotic activity of the lactoperoxidase-thiocyanate-hydrogen peroxide system in the calf abomasum.

The lactoperoxidase system which had been previously shown to kill Gram-negative organisms (eg, coliforms, salmonellae, pseudomonads) in vitro, was found to be activated in vivo. The lactoperoxidase was provided by the milk and the thiocyanate either by the milk or by its secretion in the abomasum. The third factor was provided either by a H2O2 generating system (glucose oxidase and glucose) or by H2O2 producing lactobacilli. The latter occur naturally in large numbers in the abomasum of the calf.

Abomasum↗
PubMed1977

Influence of the heat treatment of human milk on some of its protective constituents.

Human milk was subjected to heat treatments of graded severity and examined for its content of immunoglobulins, lactoferrin, lysozyme, vitamin B12-and folate-binder proteins, and lactoperoxidase. Holder pasteurization (62.5degrees C 30 minutes) reduced the IgA titer by 20%, and destroyed the small content of IgM and most of the lactoferrin. Lysozyme was stable to this treatment, but with an increase in temperature there was progressive destruction, to near 100% at 100degrees C. The same was broadly true of the capacity of milk to bind folic acid and potect it against bacterial uptake; with vitamin B12 the binder was more labile at 75degrees C than at 100degrees C. The milk contained no detectable lactoperoxidase.

Escherichia coli↗
PubMed1977

Artificial liver: the effect of ACAC microencapsulated charcoal hemoperfusion on fulminant hepatic failure.

Control trials and statistical analysis were carried out to assess the effects of albumin-collodion microencapsulated activated charcoal (ACAC) hemoperfusion on fulminant hepatic coma. A rat model of galactosamine induced fulminant hepatic coma was used. Rats which did not recover died at 3.0+/-0.6 days after galactosamine injection. Those which survived this period recovered. Forty-eight hours after galactosamine injection, a test group of 21 rats were treated with 1 hour hemoperfusion and compared with an untreated group of 23 rats. 71.4% of the treated group survived as compared to 30.4% of the untreated rats. Statistical analysis (t test) shows a significant increase in recovery for the treated group (less than 0.01). Biochemical and histological results will be discussed.

Albumins↗
PubMed1976

Chemical and biological properties of extracellular slime produced by Staphylococcus aureus grown in high-carbohydrate, high-salt medium.

Slime material produced by three strains of Staphylococcus aureus grown in the high-carbohydrate, high-salt modified 110 medium contained ribitol teichoic acid and, in two of the three strains, a basic protein reacting with antisera to S. aureus whole cells and cell walls. The basic protein differed chemically and serologically from cell wall mucopeptide and protein A. Substances resembling the capsular antigen of the Smith diffuse strain of S. aureus were not detected, nor were any other uronic acid-containing components. When cell walls, slime material, and teichoic acid were injected intradermally into cows, only cell walls produced a skin reaction.

Animals↗
PubMed1976

Nonspecific bactericidal activity of the lactoperoxidases-thiocyanate-hydrogen peroxide system of milk against Escherichia coli and some gram-negative pathogens.

Two strains of Escherichia coli and one strain each of Salmonella typhimurium and Pseudomonas aeruginosa were killed by the bactericidal activity of the lactoperoxidase-thiocyanate-hydrogen peroxide system in milk and in a synthetic medium. H2O2 was supplied exogenously by glucose oxidase, and glucose was produced at a level which was itself noninhibitory. Two phases were distinguished: the first phase was dependent on the oxidation of SCN(-) by lactoperoxidase and H2O2, which was reversed by reducing agent, and the second phase was dependent on the presence of accumulated H2O2, which was reversed by catalase. The latter enzyme could also reverse the first phase, but only when present in excessive and unphysiological levels. The bactericidal activity was greatest at pH 5 and below, and it depended on the SCN(-)concentration and on the number of organisms. Since raw or heated milk neutralizes the acid barrier against infection in the stomach, the bactericidal system discussed may contribute to the prevention of enteric infections in neonates.

Animals↗
PubMed1976

Inhibition of the bactericidal activity of bovine polymorphonuclear leucocytes and related systems by casein.

Polymorphonuclear leucocytes (PMN) obtained from lactating cows' udders were deficient in their ability to kill Staphylococcus aureus compared with PMN isolated from blood. However, blood PMN suspended in separated milk or in the presence of casein were similarly impaired. Casein was found to inhibit in vitro the bactericidal activities of histone, the lactoperoxidase-H2O2-KI system and PMN lysates. Electron microscopy showed that casein was ingested by PMN with the formation of phagocytic vacuoles. These observations provide the basis of a hypothesis explaining the bactericidal deficiency of milk PMN and the consequent susceptibility of the udder to infection.

Animals↗
PubMed1975

Antibacterial activity of the lactoperoxidase system in milk against pseudomonads and other gram-negative bacteria.

Products of thiocyanate oxidation by lactoperoxidase inhibit gram-positive bacteria that produce peroxide. We found these products to be bactericidal for such gram-negative bacteria as Pseudomonas species and Escherichia coli, provided peroxide is supplied exogenously by glucose oxidase and glucose. By the use of immobilized glucose oxidase the bacterial agent was shown to be dialyzable, destroyed by heat and counteracted, or destroyed by reducing agents. Because the system is active against a number of gram-negative bacteria isolated from milk, it may possibly be exploited to increase the keeping quality of raw milk.

Animals↗
PubMed1975

Inhibition of Escherichia coli by bovine colostrum and post-colostral milk. I. Complement-mediated bactericidal activity of antibodies to a serum susceptible strain of E. coli of the serotype O 111.

Bovine colostral whey diulted in unheated bovine milk or in Kolmer saline containing 5 per cent pre-colostral calf serum was bactericidal for Escherichia coli NCTC 9703 (serotype O 111). Whey diluted in saline without pre-colostral calf serum was inactive. Bactericidal activity was abolished by heating at 56 degrees for 30 minutes or by pre-incubating with N-acetyl-L-tyrosine ethylester, indicating that complement present in milk or pre-colostral calf serum was involved in the bactericidal activity. Undiluted colostral whey was inactive even in the presence of up to 20 per cent pre-colostral calf serum, probably due to a prozone effect. Milk heated at 80 degrees for 10 minutes was also shown to have a limited anti-complementary effect. Post-colostral milk from some cows had bactericidal activity, whereas similar milks from other cows were either inactive or active only after addition of pre-colostral calf serum, indicating that antibodies to E. coli or complement or both may or may not be present in the post-colostral milk of different cows. The implications of these findings in relation to the bacterial flora of the intestinal tract of neonates are discussed.

Animals↗
PubMed1975

Inhibition of Escherichia coli by bovine colostrum and post-colostral milk. II. The bacteriostatic effect of lactoferrin on a serum susceptible and serum resistant strain of E. coli.

Two strains of Escherichia coli were inhibited by complement-inactivated cow serum and to a lesser extent by precolostral calf serum devoid of specific antibodies. They were not inhibited by undiluted colostral whey or milk but colostral whey became bacteriostatic after dialysis or dilution in Kolmer saline and addition of precolostral calf serum or lactoferrin. The inhibition in all these fluids was due to iron-binding proteins (transferrin or lactoferrin). Undiluted dialysed milk was not inhibitory because of its low content of lactoferrin but became inhibitory after addition of 1 mg/ml of lactoferrin. The lack of inhibition in undiluted whey is due to the high concentration of citrate in colostral whey (and milk) and it is suggested that citrate competes with the iron-binding proteins for iron and makes it availabe to the bacteria. Addition of bicarbonate, which is required for the binding of iron by transferrin and lactoferrin, can overcome the effect of citrate; hence, the bacteriostatic effect of cow serum and precolostral calf serum is due to the presence of both transferrin and bicarbonate as well as the low lefel of citrate.

Animals↗
PubMed1975

The effect of intramuscular and intramammary vaccination of cows on antibody levels and resistance to intramammary infection by Staphylococcus aureus.

Cows were vaccinated simultaneously by the intramuscular and intramammary route with formolised Staphylococcus aureus cells of strains BB, Mexi and 3528. Vaccination resulted in slight increases in serum agglutinin titres, but the levels of the agglutinins in milk and colostrum were not higher in vaccinated cows than in the unvaccinated controls. Vaccination did not result in higher levels of IgM, IgG1, IgG2 or IgA immunoglobulins in serum, colostrum or milk as compared with controls. Vaccinated cows, particularly those in which strain 3528 was used, showed some resistance to infection following challenge with low numbers of viable S aureus Mexi, but there was no resistance to infection when similar numbers of the virulent BB strain were used for challenge. It is concluded that vaccination is unlikely to prevent infection of the bovine udder by S aureus.

Animals↗
PubMed1973

Virulence of two mastitis strains of Staphylococcus aureus in bovine skin: enhancement by growth in high carbohydrate-high salt medium or in raw milk.

Cows were inoculated intradermally with two strains of Staphylococcus aureus, and the severity of the resulting skin lesions was assessed on the basis of size, degree of necrosis, and in some cases by measuring the area of inflammation in histological preparations of excised skin. At least 10(6) colony forming units were required to produce a detectable skin lesion, indicating that the cow has a resistance to staphylococcal skin infection comparable to man and rabbit. The severity of the lesions produced by the two strains correlated with their known virulence in the bovine udder as mastitis pathogens. A comparison between lesions produced by cocci grown in a stock laboratory medium and those grown in the high carbohydrate-high salt modified 110 medium showed that the virulence of cocci grown in the latter medium was enhanced. The comparable effect of milk to the modified 110 medium is discussed.

Animals↗