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Biomedical subjects

C Madsen

Publications and source records attributed to C Madsen.

49 records · Page 3Linked to original sources

Subchronic toxicity study of peppermint oil in rats.

Peppermint oil was given p.o. to four groups of 28 rats at dosage levels of 0, 10, 40, and 100 mg/kg body wt. per day for 90 days. At the highest dose histopathological changes consisting of cyst-like spaces scattered in the white matter of cerebellum were seen. No other signs of encephalopathy were observed. Nephropathy was seen in the male rats in the highest dose group. A no-observed-adverse-effect level of 40 mg/kg body wt. per day was determined.

Administration, Oral↗

Squamous-cell carcinoma and oral, pharyngeal and nasal lesions caused by foreign bodies in feed. Cases from a long-term study in rats.

In a carcinogenicity study 443 out of 956 rats had chaff from oat and barley in the mouth between the molars and the gingiva. These foreign bodies caused chronic irritation and inflammation. In 173 animals disruption of tissue caused by the foreign bodies led to pathological communication between the mouth, pharynx and nose. Carcinomas in the oral, pharyngeal or nasal cavity were found in 101 of the 443 animals. Twenty-two animals died and 96 were killed because of intestinal gaseous distension. The intestinal distension was related significantly to the pathological communication between the mouth and pharynx/nose. The study shows that the foreign body-induced chronic irritation and inflammation in the epithelium of the mouth, pharynx and nose can lead to formation of squamous-cell carcinomas. The pathogenesis of the intestinal distension is discussed.

Animal Feed↗

Short-term toxicity study in rats dosed with menthone.

Menthone, a component of peppermint oil, was given p.o. to groups of 10 male and 10 female rats at dose levels of 0, 200, 400 and 800 mg/kg b.w./day, respectively, for 28 days. After 19 days the dose was reduced to 400 mg/kg b.w. in the female group receiving the highest dose. Analyses of plasma showed a dose-dependent decrease in creatinine content and a dose-dependent increase in alkaline phosphatase activity and bilirubin. The relative weights of liver and spleen were increased. Cyst-like spaces were seen histopathologically in the white matter of the cerebellum of the two highest dose groups. The no-effect level for menthone in this study was lower than 200 mg/kg b.w./day.

Animals↗

Hazard identification by methods of animal-based toxicology.

This paper is one of several prepared under the project "Food Safety In Europe: Risk Assessment of Chemicals in Food and Diet" (FOSIE), a European Commission Concerted Action Programme, organised by the International Life Sciences Institute, Europe (ILSI). The aim of the FOSIE project is to review the current state of the science of risk assessment of chemicals in food and diet, by consideration of the four stages of risk assessment, that is, hazard identification, hazard characterisation, exposure assessment and risk characterisation. The contribution of animal-based methods in toxicology to hazard identification of chemicals in food and diet is discussed. The importance of first applying existing technical and chemical knowledge to the design of safety testing programs for food chemicals is emphasised. There is consideration of the presently available and commonly used toxicity testing approaches and methodologies, including acute and repeated dose toxicity, reproductive and developmental toxicity, neurotoxicity, genotoxicity, carcinogenicity, immunotoxicity and food allergy. They are considered from the perspective of whether they are appropriate for assessing food chemicals and whether they are adequate to detect currently known or anticipated hazards from food. Gaps in knowledge and future research needs are identified; research on these could lead to improvements in the methods of hazard identification for food chemicals. The potential impact of some emerging techniques and toxicological issues on hazard identification for food chemicals, such as new measurement techniques, the use of transgenic animals, assessment of hormone balance and the possibilities for conducting studies in which common human diseases have been modelled, is also considered.

Animals↗

Childhood asthma under the north face of Mount Everest.

We assessed prevalences of symptoms of asthma, allergic rhinitis, and atopic eczema and their associations with environmental exposures among school children living in high altitude and rural Tibet. After watching an asthma symptom video, 2.8% of the children reported ever wheezing at rest and 1.4% ever severe wheezing. Residential dampness problems were the only environmental exposure that was clearly associated with children's symptoms (odds ratios 1.3 to 2.5), even if several other exposures were common. The low symptom prevalences are in accordance with the hypothesis that the western lifestyle in some way increases the risk of asthma.

Adolescent↗

Ki-67 immunoreactivity in meningiomas--determination of the proliferative potential of meningiomas using the monoclonal antibody Ki-67.

The proliferative potential of 66 human intracranial meningiomas (15 benign, 15 atypical, 15 recurrent, 13 bone-invasive, and 8 brain-invasive) was investigated by means of immunohisto-chemistry using the monoclonal antibody Ki-67. This antibody recognizes a nuclear antigen present in human cells during all active phases of the cell cycle, but absent in the resting phase. The purpose of this retrospective study was to estimate the Ki-67-labelling index (L.I.) and see if this index could help discriminate between the different groups of meningiomas. Our results demonstrated that L.I. could discriminate between benign, bone-invasive/atypical, brain-invasive meningiomas. In the recurrent group of meningiomas the L.I. decreased from the first to the last operation. We conclude that estimation of L.I. at the time of the operation might help identify meningiomas with a high growth potential and thereby give valuable information concerning the prognosis.

Adolescent↗