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Biomedical subjects

R Lemke

Publications and source records attributed to R Lemke.

At least 19 recordsLinked to original sources
PubMed1996

Neuronal expression of leukemia inhibitory factor (LIF) in the rat brain.

Very little is known about the action of the leukemia inhibitory factor (LIF) in the central nervous system. To analyze LIF expression in adult rat brain, we used non-radioactive in situ hybridization with digoxigenin-labeled RNA probes, in combination with immunohistochemistry to identify the cell types expressing LIF mRNA. Hippocampal pyramidal cells, hilar interneurons and granule cells of the dentate gyrus display strong hybridization signals, while neurons of the cerebral cortex, cerebellum, cholinergic basal forebrain nuclei, and the striatum are labeled as well. The most prominent expression in cerebral cortex is in layers IV and VI. Glial fibrillary acidic protein-positive astrocytes did not display a detectable LIF hybridization signal suggesting that LIF mRNA is predominantly expressed in neurons in the normal, adult rat brain, although a presence in resting microglial cells cannot be excluded.

Animals↗
PubMed1996

Identification and characterization of the caiF gene encoding a potential transcriptional activator of carnitine metabolism in Escherichia coli.

Expression of the Escherichia coli caiTABCDE and fixABCX operons involved in carnitine metabolism is induced by both carnitine and anaerobiosis. When cloned into a multicopy plasmid, the 3' region adjacent to the caiTABCDE operon was found to increase levels of carnitine dehydratase activity synthesized from the chromosomal caiB gene. The nucleotide sequence was determined, and it was shown to contain an open reading frame of 393 bp named caiF which is transcribed in the direction opposite that of the cai operon. This open reading frame encodes a protein of 131 amino acids with a predicted molecular mass of 15,438 Da which does not have any significant homology with proteins available in data libraries. In vivo overexpression consistently led to the synthesis of a 16-kDa protein. The caiF gene was transcribed as a monocistronic mRNA under anaerobiosis independently of the presence of carnitine. Primer extension analysis located the start site of transcription to position 82 upstream of the caiF initiation codon. It was preceded by a cyclic AMP receptor protein motif centered at position -41.5. Overproduction of CaiF resulted in the stimulation of transcription of the divergent cai and fix operons in the presence of carnitine. This suggested that CaiF by interacting with carnitine plays the role of an activator, thereby mediating induction of carnitine metabolism. Moreover, CaiF could complement in trans the regulatory defect of laboratory strain MC4100 impaired in the carnitine pathway. Expression of a caiF-lacZ operon fusion was subject to FNR regulator-mediated anaerobic induction and cyclic AMP receptor protein activation. The histone-like protein H-NS and the NarL (plus nitrate) regulator acted as repressors. Because of the multiple controls to which the caiF gene is subjected, it appears to be a key element in the regulation of carnitine metabolism.

Acyltransferases↗
PubMed1995

[Case studies of sudden infant death cases (SIDS)].

Parents and attending physicians of 100 SIDS victims were interviewed applying a questionnaire especially designed for this purpose. Particular attention was focussed on the courses of pregnancy and birth, medical check-ups and the infants' unusual behaviour during the last days of their lives. As far as possible we compared our data with the results of the Rhenian Perinatal Survey 1990.

Cause of Death↗
PubMed1994

Vitiligo and other diseases: coexistence or true association? Hamburg study on 321 patients.

In the past, several authors described an association of vitiligo with autoimmune disorders and the presence of different tissue autoantibodies. A review of the literature showed large differences in the results. Therefore, 321 patients with vitiligo (male/female ratio 114/207) were examined to see whether the frequencies of associated diseases and phenomena (i.e. Koebner phenomenon, canities praecox, halo nevi, poliosis circumscripta), the number of pigmented lesions and the presence of autoantibodies are of significance in order to support (a) a subentity of childhood vitiligo and (b) whether there is a true predisposition or association of autoimmune or other diseases in this group of patients. The data confirm earlier results of a prevalence of thyroid disease and the presence of thyroid antibodies, whereas other diseases are a random event. 6.2% of the patients had congenital nevi compared with 2.8% in a normal healthy population. Based on the results of this study and the significant higher risk for development of melanomas in this patient group, an annual checkup is recommended.

Adolescent↗
PubMed1993

Postmortem serum selenium concentrations and their possible etiological role in sudden infant death (SID).

The importance of selenium (Se) deficiency in the pathogenesis of human diseases such as Keshan Disease has been extensively studied. It is possible that low Se-levels could cause immunosuppression and be an etiological factor in Sudden Infant Death (SID). We investigated 50 serum samples (40 SID and 10 non-SID victims) by atomic absorption spectrometry. The results show that there is no evidence of a serum selenium deficiency in SID-victims in the region of Aachen. A relationship between selenium concentration and the infant immune system still remains speculative and 21 samples even showed increased serum levels. It could be necessary to define a 'local' normal range by examining a greater number of healthy infants.

Female↗
PubMed1993

[Can psycho-education of chronic schizophrenic patients have a short-term effect on drug-related attitude and behavior?].

Within a controlled intervention study with schizophrenic outpatients we investigated the question of whether regular attendance at psychoeducational training for medication management has an influence on patients' illness-related behavior. The patients in the treatment group show better outcome of compliance and some treatment-related attitudes, though without statistical significance. Despite extensive information they are no more content with their knowledge of drugs than the control group, but more aware of problems, i.e. more cautious in medication co-determination.

Adult↗
PubMed1992

Production of catecholamines in the human epidermis.

Cell-free extracts from human full thickness skin (i.e., epidermis and dermis), suction blister roofs (i.e., epidermis) and from human keratinocytes express biopterin-dependent tyrosine hydroxylase a well as phenylethanolamine-N-methyl transferase, both representing key enzymes for the biosynthesis of epinephrine. These enzyme activities could not be detected in cell extracts from human melanocytes and human fibroblasts. Since keratinocytes in the human epidermis, and in cell cultures, express a high density of beta-2-adrenoceptors, and this signal transduction system regulates intracellular calcium homeostasis, it can be concluded that epinephrine production in the epidermis activates calcium transport via the beta-2-adrenoceptor system. Our results show for the first time that the human epidermis has the capacity to independently produce epinephrine.

Biopterins↗
PubMed1992

Calcium transport and regulation in human primary and metastatic melanoma.

Thioredoxin reductase (TR) activity on primary melanomas and in surrounding skin is regulated by calcium and, therefore, TR activity can be used to measure the flux of calcium between primary tumors and their surrounding epidermis. Calcium uptake in human melanotic melanoma cell lines SKmel-23 (metastatic) and BC-PT-1 (primary) is related to the density of beta-2-adrenoceptors. The non-pigmented cell line HT-144 (metastatic), did not express beta-2-adrenoceptors, yielding a slow rate of calcium uptake compared to SKmel-23 and BC-PT-1. Cell extracts from melanotic and amelanotic melanoma tissues did not contain a phenylethanolamine-N-methyltransferase (PNMT) for the biosynthesis of epinephrine from norepinephrine and S-adenosylmethionine. However, human full-thickness skin, epidermis and cell cultures of human keratinocytes contained significant PNMT activities. Taken together, these results indicate that (a), TR can be used to monitor calcium flux between primary melanomas and their surrounding skin and vice versa and (b), calcium uptake may be regulated by stimulation of beta-2-adrenoceptors on melanotic melanomas by epinephrine synthesized in the surrounding skin.

Biological Transport↗
PubMed1991

MR-anatomy of infants hip: comparison to anatomical preparations.

The correlation between anatomical preparations and MRI images of the most important structures of newborn hips in coronal and axial orientation was performed in 18 post mortem babies. T1-weighted images present a good differentiation between cartilage, bone, ligaments and surrounding soft tissues. Coronal images give the best opportunity to study the clinically important structures of the roof of acetabulum including the labrum and the ground of the acetabulum. The latter is shown in a more detailed way by MRI than by sonography. Axial images allow additional examinations of the ventral and dorsal parts of the joint. By using both coronal and axial images the exact determination of the centering of the femur head in the hip joint is possible.

Acetabulum↗
PubMed1991

Airway resistance of the posterior nasal pathways in sudden infant death victims.

In order to test the hypothesis that infectious swelling of parts of the inner nose causes airway obstruction and is of aetiological significance for sudden infant death (SID), we measured the airway resistances of the prepared posterior nasal pathways of 55 SID victims and 7 infants who died of other causes. About 25% of the SID victims but none of the control cases had strongly elevated nasal resistances; over 4000 kPa.s.m-3 up to unmeasurable values. A histological survey showed that about 50% of the SID cases and only 1 of the control cases exhibited distinct to severe signs of inflammation of the nasal mucous membranes. No correlation was found between nasal resistance and age, sex, body weight, body length, head circumference, or histological findings. We conclude that an elevated nasal resistance plays a role in some SID cases and that SID is rather the result of different processes than a monocausal disease.

Airway Resistance↗
PubMed1988

Noninvasive PtcO2 initial slope index and invasive PtcO2 arterial index as diagnostic criterion of the state of peripheral circulation.

Transcutaneous PO2 (PtcO2), PaO2, PtcO2 arterial index (ARI; PtcO2/PaO2), and the initial slope index (ISI; [delta PO2/min]/starting PtcO2) were measured in 42 healthy volunteers, 12 patients with stable circulation and respiratory insufficiency, and ten patients with insufficient peripheral circulation in cardiogenic shock in order to investigate whether ARI and ISI can be used to detect insufficient circulation. The ISI was measured by placing a PtcO2 electrode on the forearm and interrupting blood flow by inflating a cuff until the PtcO2 dropped to zero. After releasing the cuff pressure, the initial slope of the PtcO2 trace was determined in order to calculate the ISI. In the PtcO2 range between 40 and 100 torr, the ARI and ISI did not depend on the PtcO2 magnitude. In all groups, the ISI behaved similarly to the ARI. We conclude that the noninvasive ISI and invasive ARI are able to differentiate between stable and insufficient peripheral circulation (ISI less than 0.75, ARI less than 0.8; p less than .001).

Adult↗
PubMed1987

[Morphologic and clinical aspects of alveolitis].

Non-infectious "pneumonias" are said to occur more frequently, among other things as a result of increasing environmental pollution. There is still no final systematizations of these pathogenetic complex diseases that is universally accepted; they are mainly defined according to pathomorphological criteria and are summarily termed "alveolitis" because of their localization in the acini of the lung. On the basis of a forensic expert's opinion, the problems are demonstrated.

Bronchitis↗
PubMed1987

Systolic anterior movement of the mitral valve and the Venturi effect: an in vitro study.

We constructed two different "mitral valve" models in order to investigate the influence of the Venturi effect on SAM. According to our results, SAM can be caused as a result of a subvalvular obstruction. In this case, the valve itself does not contribute to the degree of outflow tract obstruction (first model). In the second model, the valve itself contributes to the degree of outflow tract obstruction. In both models only the Venturi effect is the cause of SAM. We conclude that different anatomic abnormalities causing a Venturi effect can induce SAM.

Cardiomyopathy, Hypertrophic↗