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Biomedical subjects

U Siebert

Publications and source records attributed to U Siebert.

61 records · Page 4Linked to original sources
PubMed1996

Observations on the helminths of harbour porpoises (Phocoena phocoena) and common guillemots (Uria aalge) from the Belgian and German coasts.

Between February 1990 and July 1991, 18 harbour porpoises (Phocoena phocoena) and 248 common guillemots (Uria aalge), found dead along the Belgian and German coasts, were examined for their burden of helminths. A total of three species were found in the guillemots (one cestode, one nematode and one pentastomid), and six species in the porpoises (one trematode, one cestode and four nematodes). Among the guillemots the burden of helminths was not statistically different between juvenile and adult birds. The deaths of the birds were apparently not related to the parasite infections. In contrast, the adult porpoises were more heavily parasitised than the juveniles, except for one young porpoise stranded on the Belgian coast. In the porpoises, four species of parasites had a pathological effect and Torynurus convolutus was responsible for the death of one animal from the Belgian coast and three from the German coast.

Animals↗
PubMed1993

Effect of photoperiod on the development of wheel-running activity rhythms in LEW/Ztm rats.

Wheel-running activity of LEW/Ztm rats is characterized by a multimodal pattern consisting of two activity bouts about 3-5 h apart. In this study we investigated the development of activity rhythms in LEW rats born and raised under three different photoperiods (LD 18:6, LD 12:12, and LD 6:18). Wheel-running activity was measured for 6 weeks in LD and for another 6 weeks in constant darkness (DD). The length of the photoperiod influenced the phase relationship between the two activity bouts only during the first week after weaning. Then, the characteristic activity pattern was established independently of the length of the photoperiod. However, development under long photoperiods (LD 18:6) resulted in a temporary increase in the level of activity and a significant shortening of the free-running period under DD. These results indicate that the multimodal activity pattern displayed by LEW rats is controlled by separate activity oscillators that establish their unique phase relationship early during development.

Aging↗
PubMed1991

Wheel-running activity rhythms in two inbred strains of laboratory rats under different photoperiods.

Wheel-running activity patterns were studied in two inbred rat strains (ACI/Ztm and LEW/Ztm) under 24-h light-dark cycles with various photoperiods. The ACI strain was characterized by a unimodal activity pattern, whereas the LEW strain exhibited a multimodal activity pattern consisting of two activity bouts about 3-5 h apart. Harmonic spectral analyses and chi square periodograms revealed strain-specific differences in the characteristic rhythmic components of the activity pattern. The ACI strain showed only a strong 24-h rhythm, whereas the LEW strain showed additional rhythmic components with periods of 6, 4.8, and 4 h. Except in very young rats, these strain specific patterns were not affected by an experimental lengthening of the dark period. However, differences between the two strains were found in the free-running period and in the mode of entrainment. Our results indicate that the multimodal activity pattern of the LEW strain is not due to an ultradian bout oscillator, instead it may be the result of a unique coupling of multiple circadian oscillators.

Activity Cycles↗
PubMedDate not supplied

Post-mortem findings in harbour porpoises (Phocoena phocoena) from the German North and Baltic Seas.

Between 1991 and 1996, necropsies were performed on 445 harbour porpoises (Phocoena phocoena), in various states of preservation, stranded on German coasts or accidentally caught by German fishermen. The animals originated from the North and Baltic Seas, and 133 were considered suitable for histopathological, immunohistochemical and microbiological examination. Most of the lesions in these 133 porpoises were caused by parasites, in particular in the respiratory tract, two-thirds of the animals exhibiting pneumonia associated with the parasites. Pneumonia was considered to be the cause of death in 46% of the stranded subadult and adult animals. The findings gave no evidence of any epidemic due to bacterial or viral infection. Bacteriological examination suggested that pneumonia was mainly caused by secondary bacterial infection and not by parasitic infestation alone. Beta-haemolytic streptococci were considered to be the main infectious agents. Morbillivirus antigen was not detected immunohistochemically.

Animals↗
PubMedDate not supplied

[Reliability of manual medical examination techniques of the cervical spine. Study of quality assurance in manual diagnosis].

OBJECTIVE: Chiropractic techniques are of particular importance for the examination of the cervical spine. The aim of this study was to assess interexaminer reliability of examination techniques of the cervical spine in subjects with and without musculoskeletal distortions of the neck. The interrater method was used with five independent examiners. METHOD: Twenty patients suffering from neck diseases and 20 asymptomatic subjects of similar age and gender were randomized and assessed by five examiners blind to patient histories. Statistical analysis was carried out using multiple logistic regression and the calculation of kappa. RESULTS: Compared to asymptomatic subjects, patients experienced pain significantly often when pressure was applied to the cervical zygapophysial joints and the superficial neck muscles (p < or = 0.05 and p < or = 0.01). In addition, segmental function tests induced kinesialgia significantly more often in patients than in asymptomatic subjects (p < or = 0.05 and p < or = 0.01). A significant relationship was not found between the patient's health status and the findings from muscle palpation and functional examination of the motion segments. The assessment of agreement within examiners beyond chance had to be calculated, aside from for few exceptions, little to moderate (0.2 < kappa < or = 0.6). CONCLUSIONS: Chiropractic techniques are an essential part of every examination of the cervical spine. The clinical impact has not been scientifically established until up to now. Based on our findings and literature, we conclude that interexaminer reliability of manual diagnosis in the examination of the cervical spine should be improved by standardizing the examination process and setting guidelines for documentation and evaluation criteria. Controlled and frequently repeated training sessions also contribute to the reproducibility of findings from manual examinations.

Adult↗