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Biomedical subjects

K Jantzen

Publications and source records attributed to K Jantzen.

At least 19 recordsLinked to original sources
PubMed2001

[A modification of the in ovo-method for the determination of the antihemorrhagic activity of plant extracts].

Up to now there has been only a method available for testing the antihaemorrhagic activity of plant extracts, in which chicken embryos had to be transferred to a special container on the fifth day of incubation. Furthermore, the test could not be conducted on the extraembryonal circulatory system until two days later. In the test method described here the embryos remain inside the egg. After removal of the eggshell through the air cell and removal of the inner shell membrane, direct access to the extraembryonal circulatory system is possible, minimising external influences on the test system. This represents a dramatic simplification in technique and permits testing already on the fourth day of incubation. The application of this method to determine the antihaemorrhagic properties of samples has the advantage of permitting the simple and quick production of haemorrhages by snake venom on the yolk sac circulatory system.

Animals↗
PubMed1998

A study of the efficacy of a comprehensive memory enhancement program in healthy elderly persons.

Well educated, high functioning older adults (ages 60-90) were given a comprehensive memory enhancement training program to determine the effectiveness of the program in increasing cognitive performance and positively influencing self-assessments of memory efficacy. The 68 subjects who participated in the memory enhancement training were compared to 74 subjects who were enrolled in a video control group. Between subject differences were analyzed prior to the interventions and at three time points following the interventions (immediately post, 3 months and 6 months). Only one cognitive measure, assessing verbal memory, revealed a significant difference between the groups, with participants in the memory enhancement group showing less decline from baseline than the video control group immediately following the intervention but with no difference between groups at 6 months post-intervention. Several self-report measures showed that the memory enhancement training subjects experienced improved memory functioning and decreased memory concerns relative to the video control group. The self-reported effects of the training were sustained over the 6-month follow-up period.

Adult↗
PubMed1992

[Uterine metastases of malignant melanoma].

Uterine metastases of extragenital malignomas are rarely presented in literature. Malignant melanoma as primary tumour is described more often than can be expected with regard to its relative incidence in comparison to other malignomas. If the uterus is involved in melanoma disease, mostly cervix and myometrium are affected, endometrial metastases are considered to be very rare. If the primary tumour is known, bleeding abnormalities frequently lead to the diagnosis of uterine metastases, but occasionally abnormal bleeding appears to be the first symptom of melanoma disease. In the following another such case is described and an additional case of endometrial metastases of malignant melanoma is presented.

Aged↗
PubMed1987

Partial overlapping of binding sequences for steroid hormone receptors and DNaseI hypersensitive sites in the rabbit uteroglobin gene region.

Four DNaseI hypersensitive (HS) chromatin regions were found in the uteroglobin locus located at -3.7, -2.4, -0.1 and +4.1 kb with respect to the transcription start site of the gene. The three sites upstream of the gene are only detected in the hormonally stimulated endometrium and disappear after hormone withdrawal, whereas the site at +4.1 is also found in tissues that do not express uteroglobin. In the -2.4 HS region, which is strictly dependent on progesterone treatment, three DNaseI sites are clustered within a 240 bp DNA segment that contains 20 imperfect repeats of an octanucleotide motif. Upstream of the uteroglobin gene there are three regions containing binding sites for the glucocorticoid and the progesterone receptors, located at -3.7, -2.6/-2.7 and -2.4. The -2.4 region contains two binding sites for the hormone receptors flanking the central HS site. In footprinting experiments with naked DNA binding of the receptor also renders this site more susceptible towards digestion with DNaseI. The -2.6/-2.7 region contains three binding sites for the hormone receptors located 140 bp upstream of the HS -2.4. While the -3.7 HS is also located within a receptor binding fragment, there is no binding of the hormone receptors to the promoter region. Thus, interaction of the receptor with DNA sequences far upstream from the promoter alters the chromatin conformation of neighbouring sequences and results in transcriptional activation.

Animals↗
PubMed1986

The DNase I sensitive domain of the chicken lysozyme gene spans 24 kb.

We have determined the DNase I sensitive chromatin domain of the lysozyme gene in the hen oviduct. When nuclei were digested with DNase I, about 14 kb of upstream and 6 kb of downstream sequences in addition to the 4 kb long transcribed region were preferentially degraded. The transcription start site is located near the center of the approximately 24 kb long sensitive domain. At the 3' boundary there is a rather abrupt transition from the DNase I sensitive to the resistant chromatin configuration whereas at the 5' border this transition occurs in a gradual fashion over 6-7 kb of DNA. No obvious correlation between the boundaries of the domain and repetitive sequences could be established. DNase I-hypersensitive sites are clustered within the boundaries of the sensitive domain which seems to represent a functional unit of the gene.

Animals↗
PubMed1975

[The influence of ethrane on the electro- and pentylenetetrazol-convulsions in mice (author's transl)].

The influence of Ethrane upon electro shock and pentylenetetrazol-induced convulsions was studied in mice. Similar to other inhalation anaesthetics and to barbiturates Ethrane exerts a powerful anticonvulsive activity. There is a dose response relationship between the rate of electro shock (20 mA/0.2 sec) induced convulsions and inspiratory Ethrane concentration, convulsions being completely prevented by 1.5 vol.-percent of Ethrane. The LD(50) of pentylentetrazol increases five fold under a 2 vol.-percent Ethrane anaesthesia.

Anesthesia, Inhalation↗