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Biomedical subjects

F van Knapen

Publications and source records attributed to F van Knapen.

At least 55 records · Page 3Linked to original sources
PubMed1997

The effect of electrical stimulation on the water-holding, capacity and protein denaturation of two bovine muscles.

The effect of low-voltage electrical stimulation on the water-holding capacity and protein denaturation of bovine longissimus thoracis and semimembranosus was studied in eight electrically stimulated (85 V, 14 Hz, 15 s; immediately after slaughter) and eight nonstimulated Friesian Holstein bull carcasses. At 24 h postmortem longissimus thoracis and semimembranosus were sampled for drip loss, thaw loss, filter paper wetness, myofibrillar water-holding capacity, protein content of drip, protein solubility, myofibrillar ATPase-activities, and bound phosphorylase. Electrical stimulation resulted in higher (P < .05) drip losses and filter paper wetness and lower (P < .05) myofibrillar water-holding capacity of semimembranous samples. The increased drip loss coincided with decreased (P < .05) sarcoplasmic protein solubility, decreased (P < .05) myofibrillar ATPase-activity, and decreased (P < .05) protein concentration of drip. In the longissimus thoracis, electrical stimulation resulted in a lower (P < .05) myofibrillar water-holding capacity. However, this was not reflected in higher drip losses. In this muscle, only a decreased (P < .05) sarcoplasmic protein solubility and increased (P < .05) amount of bound phosphorylase was observed. The results indicated that the negative effect of electrical stimulation on drip loss is possibly the result of myosin denaturation, which is determined by postmortem pH and temperature fall and thus varies by muscle studied. Sarcoplasmic protein denaturation seemed not to be involved in determining water-holding capacity.

Adenosine Triphosphatases↗
PubMed1996

[No effects of the educational campaign among family physicians on Toxocara infections in humans].

OBJECTIVE: To evaluate the effect on general practitioners of an educational campaign about Toxocara and toxocariasis in man. DESIGN: Descriptive. SETTING: General practices in the Netherlands. METHOD: Telephone interviews of two groups of general practitioners before (n = 135) and 6 months after (n = 105) an educational campaign in 1993. RESULTS: No significant difference in knowledge concerning Toxocara and toxocariasis was observed in the two interviews. From the general practitioners interviewed, 44% considered Toxocara infections a zoonosis and 13-15% knew that 90-100% of puppies are infected. The clinical symptoms that were mentioned, agreed very little with the actual symptoms of toxocariasis. CONCLUSION: The knowledge of this important zoonosis was in general inadequate and the campaign to improve the awareness failed.

Animals↗
PubMed1996

Suggestions for the construction, analysis and use of descriptive epidemiological models for the modernization of meat inspection.

There is consensus that scientifically validated, quantitative assessments of actual public health risks are a prerequisite for any sound modernization of current meat inspection procedures. This article outlines how such analyses could be conducted. Approaches that rely heavily upon extrapolations from theoretical dose-effect relationships are inadequate for the assessment of microbiological health risks associated with the production and consumption of meat. The use of highly structured and very elaborate descriptive epidemiological models covering the entire period from stable to table can be considered a promising solution. Health risks can be quantified by means of incidence rates and the influence of risk factors by means of odds ratios and (population) attributable fractions. A great advantage is that when it is not possible to quantify risks exactly, the descriptive models are detailed enough to be used in a hazard analysis critical control point (HACCP)-like approach and for writing validated codes of good manufacturing practice (GMP). There are, however, several conditions which have to be met before risk assessment can become the foundation of safety assurances for meat, such as active legislative support and the setting up of monitoring systems for zoonoses and other health hazards in animals and humans.

Data Collection↗
PubMed1996

EU experimental study on wild boar trichinellosis.

From January 1994 onwards the Council Directive 92/45 EEC concerning the examination of wild game meat for trichinellosis is valid. Laboratory methods required are identical to those used for the examination of pork. In an international experiment the suitability of these methods to control wild boar meat was tested. Required meat parts of experimentally with T. spiralis infected wild boars were shipped to seven laboratories in Europe under code. It was concluded that trichinoscopy and pool sample digestion methods meant for pork examination could equally well be used for control of wild boar meat. The so called Trichomatic method required a few adaptations. Moreover it was demonstrated that extra washing procedures were required to prevent cross contamination between samples with Trichomatic equipment.

Animals↗
PubMed1995

Prevalence of IgG antibodies to Trichinella spiralis in dogs in Macedonia, northern Greece.

An enzyme-linked immunosorbent assay (ELISA) was used to detect T. spiralis infection in dogs, using larval T. spiralis excretory-secretory (ES) antigen. Forty-three (4.3%) dog sera out of 1000 revealed the presence of IgG T. spiralis. The positive sera were distributed in three groups; 21 (2.1%) weakly positive, 14 (1.4%) moderately positive, and eight (0.8%) strongly positive.

Animals↗
PubMed1995

Prevalence of antibodies to Toxoplasma gondii in cattle and swine in The Netherlands: towards an integrated control of livestock production.

Serological surveys of the prevalence of antibodies against Toxoplasma gondii were carried out amongst swine and cattle in the Netherlands. Data were analysed according to the different categories of animals. The results show very low seroprevalences of Toxoplasma gondii in finishing pigs (1.8%) and in fattening calves (1.2%). In sows and dairy cattle, respectively, seroprevalences of 30.9% and 27.9% respectively, were found, demonstrating clearly the environmental infection pressure and illustrating the importance of housing and management in establishing low infection rates. Substantially different seroprevalences were found between dairy cattle sampled in the North and in the South of the Netherlands (13.1% and 42.6%, respectively). The infection rates in the samples from finishing pigs, fattening calves, and dairy cattle demonstrate that seroprevalences in individual farms or herds may differ considerably. Investigation of the factors involved can be useful in determining the causes of infection and for developing measures with regard to prevention. The very low seroprevalences in finishing pigs and fattening calves indicate, however, that the production of toxoplasma-free meat may be well within reach in modern husbandry. Since farm animals easily are infected, serological screening of individual farms or herds for the absence of T. gondii infection, as a part of the Integrated Quality Control programme, can be helpful in determining the quality of livestock production and in developing certain standards of hygiene for individual farms.

Animals↗
PubMed1995

Susceptibility of Encephalitozoon cuniculi to several drugs in vitro.

In the light of the increased incidence of human Encephalitozoon infections and the absence of an established treatment protocol, a simple in vitro testing method to compare activities of drugs against Encephalitozoon cuniculi was developed. With this in vitro method, the 50% inhibitory concentrations of fumagillin, thiabendazole, albendazole, oxibendazole, and propamidine isethionate for E. cuniculi in rabbit kidney cells were determined. Itraconazole, toltrazuril, metronidazole, ronidazole, and ganciclovir were ineffective in this testing system.

Animals↗
PubMed1994

Toxocara seroprevalence in 5-year-old elementary schoolchildren: relation with allergic asthma.

Toxocara seroprevalence and the relation between Toxocara seroprevalence and allergic asthma were investigated in Dutch schoolchildren aged 4-6 years. Data on Toxocara antibodies, allergen-specific immunoglobulin E, allergic manifestations, and risk factors (pets and playgrounds) were obtained from 235 children from The Hague and 477 from Rotterdam, the Netherlands. The surveys were carried out from September 1987 to January 1988 in The Hague and in March and April 1989 in Rotterdam. Logistic regression was used to evaluate putative relations. Toxocara seroprevalence was higher in The Hague (11%) than in Rotterdam (6%), but this difference was not quite significant. Seroprevalences varied widely among schools. No differences between socioeconomic categories or between the sexes were found. Occurrences of asthma/recurrent bronchitis and hospitalization due to asthma/recurrent bronchitis were significantly associated with seroprevalence. Furthermore, a marginally significant relation with eczema was found. Immunoglobulin E specific for inhaled allergens occurred significantly more often in the Toxocara-seropositive group. The risk factors investigated were not related to seroprevalence. It is suggested that Toxocara, among other environmental factors, may stimulate polyclonally immunoglobulin E production, including allergen-specific immunoglobulin E, and thus may contribute to the manifestation of allergic asthma and possibly of eczema in children predisposed to allergy.

Animals↗
PubMed1994

Meningeal irritation: possible manifestation of cerebral Echinococcus infestation.

A patient with meningeal irritation and a small occipital cystic lesion is presented. Based on serological tests, the condition was diagnosed as presumably echinococcosis. To our knowledge, meningeal irritation has previously not been reported as an early symptom of cerebral Echinococcus infestation. Cysticercosis is discussed as a possible differential diagnosis.

Adult↗