Biomedical subjects

J Kupfer

Publications and source records attributed to J Kupfer.

At least 37 records · Page 2Linked to original sources

PubMed1997

Stress-induced changes in the functional electromyographic activity of the masticatory muscles.

The present study was undertaken to assess the effect of a non-experimental emotional stress situation on the functional electromyographic (EMG) activity of the masticatory muscles. The material comprised 15 dental students without signs and symptoms of disorders from the temporomandibular system. The activity of the masseter and anterior temporalis muscles was recorded bilaterally by means of surface EMG. The subjective degree of helplessness of the subjects was assessed and related to the EMG activity response, to assess a possible interrelation. The EMG activity during the stress situation was significantly greater than for the non-stress situation. This shift in EMG activity was seen for all the muscles and all the functions analyzed. No significant gender differences were found. When the subjective degree of helplessness is taken into consideration, women showed significantly higher ratings than male subjects. The Helplessness Scale ratings correlated with the changes in EMG activity.

Adult↗

PubMed1996

Autocrine induction of DNA synthesis by mechanical injury of cultured smooth muscle cells. Potential role of FGF and PDGF.

To determine whether replication of arterial smooth muscle cells (SMCs) in response to mechanical injury would occur in the absence of serum and other cells, we created an in vitro model in which confluent, growth-arrested cultures of rat SMCs were injured by gentle pressure of a soft plastic tube and then kept in serum-free medium for up to 4 days. Replication of SMCs in and around the injury, as measured by tritiated thymidine incorporation, was noted within 24 hours and peaked at 48 hours after injury, whereas noninjured cells remained quiescent. An increased expression of platelet-derived growth factor (PDGF) A mRNA, noted 6 hours after injury, was followed by an increased PDGF AA immunoreactivity in SMCs in and around the zone of injury at 24 and 48 hours after injury. A PDGF A chain antisense oligonucleotide inhibited 87.0 +/- 4.0% (P < .005) of SMC replication in the injury zone, whereas the corresponding sense oligonucleotide reduced SMC replication by only 37.2%. An antibody to fibroblast growth factor (FGF) almost completely inhibited SMC replication in the injured zone, whereas an antibody to PDGF AA was without effect. Incubation of SMCs with FGF increased PDGF A mRNA levels in SMCs, and 5 mumol/L PDGF A antisense oligonucleotides reduced FGF-induced SMC replication by 62%. Taken together, these results demonstrate that injured rat SMCs in culture release FGF that activates DNA synthesis of neighboring SMCs both by a direct mechanism and by stimulating the production of PDGF AA.

Animals↗

PubMed1995

[Follow-up and typologic description of requirements in an intensive care unit].

Presented is the description of the objective, environmental demands of a medical intensive care unit (MICU). These are significant as the situational background of the subjective perception of working-situation by nurses and physicians. Therefore on the one hand a strain-index of the MICU in process of 101 days shows the daily variation of straining variables and a cycle of 33 days. On the other hand, we found days with a specific pattern of straining variables by a factor-analysis. These results were discussed on a stress-theoretical view.

Adult↗

PubMed1992

Platelet-derived growth factor isoforms decrease insulin-like growth factor I gene expression in rat vascular smooth muscle cells and selectively stimulate the biosynthesis of insulin-like growth factor binding protein 4.

Platelet-derived growth factor (PDGF) is believed to be a critical mediator of vascular smooth muscle cell (SMC) proliferation. Because insulin-like growth factor (IGF) I (IGF-I) functions as a progression factor for the mitogenic effects of PDGF, we hypothesized that IGF-I gene expression and the production of IGF binding proteins (IGFBPs) by cultured rat aortic SMCs might be regulated by one or more of the three isoforms of PDGF: PDGF-AA, -BB, and -AB. IGF-I gene expression was highly dependent on cell density: IGF-I mRNA transcripts decreased markedly as a function of cell confluence. IGF-I mRNA content was inhibited to a similar degree by PDGF-AA, -BB, and -AB through a mechanism requiring protein synthesis. The inhibition was readily apparent at 4 hours, reaching approximately 25% of control levels after 24 hours. Radioimmunoassayable IGF-I was only barely detectable in SMC-conditioned serum-free medium and not significantly modulated by PDGF. Western ligand blot revealed that vascular SMCs release 30-kd and 24-kd IGFBP into serum-free conditioned medium. PDGF isoforms did not significantly alter release of the 30-kd IGFBP but evoked a fivefold to sixfold increase in the 24-kd IGFBP. The 24-kd IGFBP was found to comigrate with IGFBP-4, a recently identified binding protein that inhibits IGF action. The 30-kd protein was not merely a glycosylated form of IGFBP-4, because it was not sensitive to N-glycanase digestion. PDGF-AA, -BB, and -AB markedly induced expression of IGFBP-4 mRNA in a time- and concentration-dependent fashion. Vascular SMCs also express IGFBP-2 mRNA, but its abundance was not induced by PDGF. In conclusion, PDGF evokes a complex pattern of regulation of genes in the IGF/IGFBP system. By inhibiting IGF-I production and specifically inducing biosynthesis of the inhibitory binding protein IGFBP-4, PDGF may set in motion mechanisms to limit the final magnitude of the mitogenic response.

Animals↗

PubMed1992

[The Giessen Symptom Questionnaire for children and adolescents].

The Giessen Subjective Complaints List for children (GSCL-C) a questionnaire on physical complaints in self-image form, was developed out of the adult GSCL. The questionnaire contains items from the areas; general wellbeing, vegetative complaints, pains, emotionality and children's complaints. The subject is asked to estimate the degree of distress caused by each complaint (never/rarely/sometimes/often/always). Factor analysis based on a sample of 1047 schoolchildren aged 9 to 15 revealed five complaint complexes containing seven items each, which were subsequently grouped into the following scales: (1) Exhaustion, (2) Gastric Complaints, (3) Pains in Limbs, (4) Circulatory Problems, (5) Cold Symptoms. The sum of the five scales makes up the sixth scale score, overall distress. Besides describing the development of the instrument and its scales, sex- and age-related norms are given and the assessment criteria explained. Procedure and areas of application are also discussed.

Adolescent↗

PubMed1991

Abundant expression of parathyroid hormone-related protein in primary rat aortic smooth muscle cells accompanies serum-induced proliferation.

Parathyroid hormone-related protein (PTHrP), which is responsible for producing hypercalcemia in patients with humoral hypercalcemia of malignancy, has recently been identified in several normal tissues. Because PTHrP, like parathyroid hormone (PTH), is known to exhibit vasodilatory properties, we investigated the expression and regulation of PTHrP mRNA in cultured rat aortic smooth muscle cells (SMC). We report here that PTHrP mRNA is expressed in SMC and is markedly induced by serum in a time- and concentration-dependent fashion. Addition of 10% fetal calf serum to serum-deprived, confluent cells, resulted in a marked induction of PTHrP mRNA by 2 h with a peak at 4-6 h. PTHrP was detected in SMC by immunocytochemistry and radioimmunoassay of conditioned medium, and was shown to be up-regulated within 24 h after the addition of serum. The serum induction of PTHrP mRNA was blocked by actinomycin D and by cycloheximide indicating the need for protein synthesis to evoke the serum effect on PTHrP gene transcription. In addition, treatment with dexamethasone, which has been previously shown to reduce the constitutive expression of PTHrP in human cancer cells, also blunted the serum induction of PTHrP mRNA in SMC. Treatment of quiescent cells with the serum mitogens platelet-derived growth factor or insulin-like growth factor-I had no effect on PTHrP, whereas the vasoactive peptides endothelin, norepinephrine and thrombin stimulated PTHrP expression. Exogenous addition of recombinant PTHrP-(1-141) had no significant effect on SMC DNA synthesis as measured by [3H]thymidine incorporation. In summary, the abundance of PTHrP mRNA and the characteristics of its regulation in SMC suggest a major role for PTHrP as a local modulator in vascular smooth muscle.

Animals↗

PubMed1990

[Electrophysiologic criteria for the prevention of electric accidents].

About 0.25 percent of all registered industrial accidents are caused by electric current. One in 20 of these accidents has been fatal. The consequences of electric flow are determined by several factors, above all voltage, time and path of flow, type of current, and resistors within the power circuit. These are attributable to physiological criteria of conduction. Slight electric shock and death by ventricular fibrillation are close to each other by the all-or-nothing law. Conclusions are suggested for practice, and a discussion is proposed with a view to find an adequate definition of the power-related accident.

Accidents, Occupational↗

PubMed1990

[Video-screen work from an occupational medicine viewpoint].

The problem of potential health implications in visual display units (VDUS) workers does not exist when the requested ergonomic equipment of the working place is realized. Repetitive gestures and compulsive attitudes must be avoided. A healthy or optimally corrected visual organ is a prerequisite, as well. According to the hitherto knowledge there is neither to observe a harm of the germ-cells with a raised risk of malformations and abortions due to the emission of electromagnetic waves of the VDUs nor health implication of the pregnant woman. The works doctor has to realize the medical care.

Data Display↗

PubMed1988