Biomedical subjects

H L Klaasen

Publications and source records attributed to H L Klaasen.

10 recordsLinked to original sources

PubMed2000

Slaughter pigs are commonly infected by closely related but distinct gastric ulcerative lesion-inducing gastrospirilla.

An association between (unculturable) gastrospirillum-like organisms (GLO) and ulcerative lesions in the pars oesophagea in stomachs of swine has been claimed. In dogs GLO detected by microscopy may represent several Helicobacter species or subspecies. Therefore we investigated which Helicobacter spp. are present in stomachs of swine and their possible association with ulcerative lesions of the pars oesophagea. The presence of Helicobacter spp. in the antrum and pars oesophagea in 122 stomachs of slaughter swine was determined by microscopy (n = 122), by culture on selective and nonselective media (n = 112), and by a genus-specific 16S ribosomal DNA (rDNA) PCR (n = 80). GLO could not be cultured. Phylogenetic analysis of 43 16S rDNA fragments (out of 54 PCR-positive biopsy specimens) revealed the presence of Helicobacter heilmannii type 1 in 42 of them. This correlated with the presence of bacteria with GLO morphology. Helicobacter bilis 16S rDNA was amplified directly from one sample harboring bacteria with H. bilis morphology. The association between Helicobacter spp. and gastric lesions was investigated with a second group of 41 pigs with (n = 21 cases) or without (n = 20 controls) gastric lesions. Fifteen of the 21 cases were positive by PCR or microscopy, compared to 7 of 20 of the controls (P = 0.03). 16S rDNA sequence analysis of 7 of 14 PCR-positive cases revealed the presence of H. heilmannii type 1. Microscopy showed bacteria with GLO morphology. One sample (cases) was culture negative but PCR positive for Helicobacter pullorum-related 16S rDNA. In conclusion, our findings indicate that H. heilmannii type 1 is the predominant Helicobacter spp. in the stomachs of pigs and that its presence is associated with ulcerative lesions in the pars oesophagea.

Abattoirs↗

PubMed1999

Detection of the beta2 toxin gene of Clostridium perfringens in diarrhoeic piglets in The Netherlands and Switzerland.

The two studies presented here were done to determine the prevalence of the alpha, beta, epsilon and enterotoxin genes and the novel beta2 toxin gene of Clostridium perfringens in neonatal or pre-weaned piglets with diarrhoea or necrotic enteritis. All C. perfringens isolates were positive for the alpha and negative for the epsilon and enterotoxin gene, implying that only non-enterotoxigenic type A and C strains were detected. The most important findings were the relatively high prevalence of the beta2 toxin gene in isolates from diarrhoeic piglets in both studies, and, in one of the two studies, absence of strains with only the alpha and beta toxin gene. These data are supportive for the suggestion of a causal relationship of beta2 toxin-producing strains with digestive tract diseases in piglets.

Animals↗

PubMed1994

Nitric oxide-derived urinary nitrate as a marker of intestinal bacterial translocation in rats.

BACKGROUND/AIMS: Bacterial translocation across the gut wall may lead to bacteremia and sepsis. Bacteriological analyses are laborious and time consuming, which precludes a rapid diagnosis of bacterial translocation. Synthesis of nitric oxide by macrophages is a primary response to bacterial infections. Therefore, the aim of this study was to examine whether NO-derived nitrate excretion in urine can be used as a rapid and quantitative marker of intestinal bacterial translocation. METHODS: The kinetics of urinary nitrate excretion was determined in rats intraperitoneally injected with increasing doses of Salmonella enteritidis lipopolysaccharide. Subsequently, the response to bacterial translocation was studied in rats infected orally with different doses of viable, invasive S. enteritidis. RESULTS: Increasing the lipopolysaccharide dose from 0.05 to 0.50 mg/kg resulted in a transient, dose-dependent, almost 10-fold increase in urinary nitrate excretion. Administration of the NO synthase inhibitor NG-nitro-L-arginine methyl ester merely inhibited the increase in nitrate excretion after lipopolysaccharide injection. Increasing the infective dose of viable Salmonella resulted in a time- and dose-dependent exponential increase in nitrate output. Translocation was a prerequisite for provoking a nitrate response. Total urinary nitrate excretion after infection and classical infection parameters, such as weight of the mesenteric lymph nodes and population levels of Salmonella in feces, were highly correlated. CONCLUSIONS: Urinary nitrate excretion is a quantitative, noninvasive biomarker of intestinal bacterial translocation, which can be used to follow the course of a systemic infection.

Animals↗

PubMed1993

Apathogenic, intestinal, segmented, filamentous bacteria stimulate the mucosal immune system of mice.

Segmented filamentous bacteria (SFBs) are apathogenic autochthonous bacteria in the murine small intestine that preferentially attach to Peyer's patch epithelium. SFBs have never been cultured in vitro. We have studied the effects of SFBs on the immune system of the host. Mice monoassociated with SFBs were compared with germ-free mice and with mice without SFBs but with a specific-pathogen-free (SPF) gut flora. SFBs versus no microbial flora raised the number of lymphoid cells in the lamina propria of the ileal and cecal mucosa, raised the number of immunoglobulin A (IgA)-secreting cells in the intestinal mucosa, produced elevated IgA titers in serum and intestinal secretions, and enhanced the concanavalin A-induced proliferative responses of mesenteric lymph node cells. The SPF flora had effects similar to but less pronounced than those mediated by SFBs. The results indicate that SFBs stimulate the mucosal immune system to a greater extent than do other autochthonous gut bacteria.

Animals↗

PubMed1993

Intestinal, segmented, filamentous bacteria in a wide range of vertebrate species.

Segmented, filamentous bacteria (SFBs) form a group of bacteria with similar morphology and are identified on the basis of their morphology only. The relationships of these organisms are unclear as the application of formal taxonomic criteria is impossible currently due to the lack of an in vitro technique to culture SFBs. The intestine of laboratory animals such as mice, rats, chickens, dogs, cats and pigs is known to harbour SFBs. To see whether this extends to other animal species, intestines from 18 vertebrate species, including man, were examined. SFBs were detected with light microscopy in the cat, dog, rhesus monkey, crab-eating macaque, domestic fowl, South African claw-footed toad, carp, man, laboratory mouse and rat, wood mouse, jackdaw and magpie. These results suggest that non-pathogenic SFBs are ubiquitous in the animal kingdom. Among apparently identical animals, there was considerable variation in the degree of SFB colonization. It is suggested that SFB colonization could serve as a criterion of standardization of laboratory animals.

Adult↗

PubMed1992

Intestinal, segmented, filamentous bacteria.

Segmented, filamentous bacteria (SFBs) are autochthonous, apathogenic bacteria, occurring in the ileum of mice and rats. Although the application of formal taxonomic criteria is impossible due to the lack of an in vitro technique to culture SFBs, microbes with a similar morphology, found in the intestine of a wide range of vertebrate and invertebrate host species, are considered to be related. SFBs are firmly attached to the epithelial cells of the distal ileal mucosa, their preferential ecological niche being the epithelium covering the Peyer's patches. Electron microscopic studies have demonstrated a considerable morphological diversity of SFBs, which may relate to different stages of a life cycle. Determinants of SFB colonization in vivo are host species, genotypical and phenotypical characteristics of the host, diet composition, environmental stress and antimicrobial drugs. SFBs can survive in vitro incubation, but do not multiply. On the basis of their apathogenic character and intimate relationship with the host, it is suggested that SFBs contribute to development and/or maintenance of host resistance to enteropathogens.

Animals↗

PubMed1992

Influence of a natural-ingredient diet containing Phaseolus vulgaris on the colonization by segmented, filamentous bacteria of the small bowel of mice.

The appearance of segmented, filamentous bacteria (SFBs) in the small bowel of mice is influenced by the composition of the diet, but the dietary components responsible are not known. The addition of ground, whole Phaseolus vulgaris to a natural-ingredient diet at the expense of part of the skim milk powder, ground barley and wheat middlings components, caused an increase of the colonization of the mouse small bowel by SFBs. This effect was not seen when whole Phaseolus was added to a purified diet at the expense of part of the casein, corn oil, coconut fat, corn starch, dextrose and cellulose components. In an attempt to identify the fraction of Phaseolus that might contain SFB-inducing substances, the skin and kernel fraction of the bean were added to the natural-ingredient diet. The skin and kernel fraction were found to be as effective in inducing SFB appearance as was whole Phaseolus.

Animal Feed↗

PubMed1992

Different degree of ileal colonization by segmented, filamentous bacteria in two strains of mice.

Segmented, filamentous bacteria (SFBs) are autochthonous, apathogenic inhabitants of the ileum of various animal species. Outbred Swiss (Cpb:SE) mice have significantly higher degrees of SFB colonization than do inbred BALB/c mice. The present studies were carried out to identify determinants of this strain difference. In a cross-fostering experiment it was shown that SFB colonization of the pups is determined by the strain of the pups themselves rather than by the strain of the nursing dam. Thus, maternal effects may not be involved in SFB colonization. In a cross-infecting experiment using germ-free and SFB-positive animals of the two mouse strains, it was found that ileal SFB colonization is determined by host characteristics rather than by origin of the SFBs. Thus, SFBs that are specific for a given mouse strain may not exist in the two strains of mice. It is concluded that the mouse strain difference in SFB colonization is determined by host characteristics, which probably have a genetic basis.

Animals↗

PubMed1991

Mono-association of mice with non-cultivable, intestinal, segmented, filamentous bacteria.

A technique is described so that mice mono-associated with non-cultivable, segmented filamentous bacteria (SFB's) can be produced for the first time. As SFB donors, mice were used which had an intestinal microflora consisting of both SFB's and bacteria of the genus Clostridium. Recipients were germ-free mice. It was demonstrated that the intraileal inoculation method was more effective than the orogastric route. Therefore, intestinal homogenates of donor mice were treated with filtered ethanol, diluted and administered intraileally to recipient mice. Evidence is presented that cage mates of the recipient mice were mono-associated with SFB's. The availability of these animals, i.e. in vivo monocultures of SFB's, allows taxonomic and functional characterization of SFB's, which was as yet not possible.

Animals↗

PubMed1989

Liver cholesterol concentrations in mice fed diets containing various sources of fat, carbohydrates or fiber.

Liver cholesterol concentrations were measured in mice after feeding for 30 days cholesterol-free, semipurified diets containing various sources of fat, carbohydrates or fiber. Olive oil produced significantly higher liver cholesterol concentrations than tallow, sunflowerseed oil and cocoa fat. In mice fed either fructose or sucrose liver cholesterol was significantly increased when compared with mice fed galactose or lactose. Dietary cellulose, when compared with pectin, did not influence liver cholesterol. The amount of fat in the diet, in the form of either corn oil or coconut fat, had no significant effect on liver cholesterol. It is concluded that the type of carbohydrate and fat in the diet are major determinants of liver cholesterol in mice.

Animals↗