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Biomedical subjects

J Svendsen

Publications and source records attributed to J Svendsen.

61 records · Page 4Linked to original sources
PubMed1971

Immunity to Escherichia coli in pigs: anti-enterotoxins in colostrum and serum from vaccinated and non-vaccinated sows.

Colostrum from non-vaccinated sows did not contain naturally occurring antibodies to heat labile Escherichia coli enterotoxin. Vaccination of sows by either the intramuscular or intramammary routes with a live formalinized E. coli vaccine resulted in the production of colostrum capable of neutralizing the heat labile toxin. Intramammary vaccination resulted in the production of colostrum which significantly reduced the enterotoxigenic effects of the vaccine strain of E. coli organisms but not that of a heterologous strain. Vaccination of the sows resulted in the production of serum antibodies to heat labile enterotoxin. Antibodies to heat stable enterotoxin were not demonstrable in the colostrum of either non-vaccinated or vaccinated sows.

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PubMedDate not supplied

Levels of immunoreactive insulin, neurotensin, and bombesin in porcine colostrum and milk.

High concentrations of insulin (411 +/- 214 microU/ml), neurotensin-like (265 +/- 72 pg/ml), and bombesin-like immunoreactivities (1995 +/- 288 pg/ml) were detected in porcine colostrum using radioimmunoassay, as compared to the levels found in sow blood serum at farrowing (5 microU/ml, less than 12 pg/ml, and 17 pg/ml, respectively). After 72 h of lactation, the levels of insulin and neurotensin-like immunoreactivities had decreased to 28 +/- 17 microU/ml and 89 +/- 23 pg/ml, respectively, while the bombesin-like activity remained constant. Characterization with reversed-phase high performance liquid chromatography showed that the insulin immunoreactivity eluted at the same position as the insulin standard, while the elution patterns of the neurotensin-like and bombesin-like immunoreactivities (eluted in three separate peaks) did not correspond to that of their respective standards. The biological function of the peptide hormones in colostrum/milk may be as triggers of the developmental changes taking place in the nursing neonate, especially in the gastrointestinal tract.

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PubMedDate not supplied

Insulin involvement in intestinal macromolecular transmission and closure in neonatal pigs.

The involvement of insulin in the intestinal transmission of macromolecules to blood and the cessation of this transport (intestinal closure) was studied in neonatal pigs by measuring the serum levels of the markers bovine serum albumin and fluorescein isothiocyanate labelled dextran 70,000 (FITC-D) at 4 h after gavage feeding. In naturally suckled pigs, intestinal closure at 18 h was shown to be associated with an increase in serum immunoreactive insulin (IRI) levels. Similarly, intestinal closure obtained at 18 h, by gavage feeding unsuckled pigs a total of 48 g lactose/kg, was accompanied by an increase in serum IRI levels. Neither high serum IRI levels nor closure were observed in fasted pigs or in pigs gavage fed a total of 12 g lactose/kg. The effect of exogenous insulin on intestinal macromolecular transmission was studied by injecting 5 IU insulin/kg subcutaneously at 3 and 6 h, respectively, in newborn pigs gavage fed 10 ml sow colostrum/kg at 3 h intervals. This resulted in a reduction in the transmission of the markers when tested at 12 h, in comparison to littermates receiving the same amount of colostrum and littermates suckling the sow. It appears as if insulin, reflected as high serum levels over an extended period of time, is involved in the regulation of macromolecular transmission and intestinal closure in neonatal pigs. It was speculated that insulin may be involved in these processes by initiating the synthesis of membrane structural proteins in the enterocytes.

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PubMedDate not supplied

Studies of the pathogenesis of enteric E. coli infections in weaned pigs: bacteriological and immunofluorescent studies.

Qualitative and quantitative, bacteriological studies were performed on spontaneous cases of post weaning E. coli diarrhoea (PWD). The pigs derived from a herd, D, in which the disease had persisted for a period of almost 2 years. Orally vaccinated healthy pigs from herd D and from herds A and M without the disease were also examined. The results showed that haemolytic E. coli were frequently isolated from faecal samples which had been collected 5--7 days after weaning but seldom from samples from the same pigs collected before weaning. Haemolytic E. coli dominated the aerobic intestinal flora at 3--5 days after weaning in pigs from herd D with PWD. Oral vaccination using a formalinized vaccine delayed and suppressed the occurrence of haemolytic E. coli in pigs from herd D (Table I). Intestinal counts of the bacteria showed that the number of haemolytic E. coli present in the anterior portion of the jejunum was 10(-3)--10(-5) times higher in pigs which suffered from PWD than in weaned pigs of the same age which did not show symptoms of the disease (Table II). The lowest bacterial counts in various portions of the intestine were consistently observed in the sections obtained from the orally vaccinated healthy pigs. Pure cultures of K88-negative enteropathogenic E. coli serotype O149:K91 were consistently isolated from all the diseased pigs. Fluorescent antibody studies showed that the specific strain of bacteria adhered to the villous epithelium of the jejunum in a layer which covered the villi from the tip to the base and sometimes continued down into the crypts (Figure 1). The bacterial adhesion coincided with an intensive colonization of the jejunum with the homologous E. coli serotype and was nerve observed in apparently healthy pigs which did not have symptoms of PWD. It was concluded that characteristic intestinal colonization by adhesion may occur with enteropathogenic strains of E. coli O149:K91 which lack the K88 antigen (Figure 2).

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