Search PubMed⌕ Search

Biomedical subjects

K Schmidt

Publications and source records attributed to K Schmidt.

At least 397 records · Page 22Linked to original sources
PubMed1989

Mediation of the cardiac effects of forskolin by specific binding sites.

The effects of forskolin and seven derivatives on cardiac functions were investigated by using the Langendorff technique and the results compared with the respective potencies obtained from adenylate cyclase and binding studies. In the isolated heart, forskolin increased all parameters measured in the same concentration range as demonstrated by identical EC50 values for increasing contractile force (270 nmol/L), heart rate (276 nmol/L), and coronary flow (249 nmol/L). Compared with its analogs, forskolin was the most potent agonist followed by 7-desacetylforskolin-7-ethylcarbonate, 7-desacetyl-7-propionylforskolin, 14,15-dihydroforskolin, and 7-desacetylforskolin. An identical order of potencies was obtained when these compounds were tested for their ability to inhibit [3H]forskolin binding and stimulate adenylate cyclase in a myocardial preparation. While the KI values derived from the binding experiments (386 nmol/L for forskolin) were similar to the respective EC50 values for the cardiac stimulatory effects, the ED50 values for adenylate cyclase stimulation were about 30-fold higher, e.g., 10 mumol/L for forskolin. Derivatives modified in position 9 of the molecule (1,9-dideoxyforskolin, 9,14-epoxy-15-hydroxyforskolin, and 7-desacetylforskolin-6,7:1,9-dicarbonate) had no effect on the isolated heart nor in adenylate cyclase or binding studies. This identical structure-activity profile observed in the three systems used suggests that the cardiac effects of forskolin are elicited by the one specific binding site described in this study.

Adenylyl Cyclases↗
PubMed1989

Transcranial Doppler sonographic identification of a subgroup of patients with normal pressure hydrocephalus with coexistent vascular disease and treatment failure.

We report on transcranial Doppler sonography with carbogen reactivity testing of flow velocity as applied to patients with normal pressure hydrocephalus. A subgroup can be differentiated that shows coexistent cerebrovascular disease. The surgical prognosis in these patients is bad. A flow chart demonstrating the proposed clinical examination is presented.

Adult↗
PubMed1989

Attitudes towards HIV infection and sexual risk behaviour. A survey among Danish men 16-55 years of age.

To describe attitudes towards HIV infection in relation to sexual risk behaviour and sociodemographic factors in a representative sample of Danish men 16-55 years of age, a self-administered anonymous questionnaire was distributed in connection with a personal health interview and returned by prepaid mail. The response rate was 55%, corresponding to 1,155 participants. In contrast to the official AIDS prevention strategy, 28% of the participants stated that HIV infected persons should be forbidden to have sexual relationships, and 44% that they should be registered by the authorities. 33% of the participants had had sexual behaviour which may be associated with increased risk of HIV infection: more than one female partner during the previous 12 months, sexual contact with prostitutes or sex with other men. Despite good basic knowledge of AIDS, only 41-59% of these men perceived themselves at risk, and only 47%-54% of men perceiving themselves at risk had adopted risk-reducing sexual behaviour. The results indicate a need for innovative health education of the general public about AIDS prevention at community and individual level. In the absence of effective treatment and without prospect of a vaccine in the near future the prevention of AIDS must focus on modifying behaviour associated with increased risk of HIV infection, in particular sexual behaviour.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Arteriovenous malformation of the posterior ethmoidal artery as an unusual cause of amaurosis fugax. The ophthalmic steal syndrome.

We report the case of a patient with arteriovenous malformation fed by a posterior ethmoidal artery. The pre-operative amaurotic attacks on the diseased eye subsided after removal of the malformation. Doppler sonographic examination of the peripheral ophthalmic artery showed an inversion of the blood flow direction postoperatively. We describe a concept of an ophthalmic steal syndrome treated in this patient by removal of an arteriovenous malformation.

Arteries↗
PubMed1989

[The pharmacology of the lipoxygenase inhibitors oxphaman (1-(2,5-dihydroxybenzylidene)aminoadamantane) and oxphalin (1-(3,4-dihydroxybenzylidene)-2,4,6-trimethylaniline].

Oxphaman and particularly oxphalin, among other phenolic azomethines, have been proven as strong inhibitors of lipoxygenases (LOX) from reticulocytes, soybean, thrombocytes as well as of quasi-LOX (hemoglobin) with IC50 values which correspond with those of known LOX inhibitors. The 5-LOX is likewise strongly, the cyclooxygenase of sheep seminal vesicles only weakly inhibited. Nevertheless, antiinflammatory effectivity was found in some carrageenin-induced inflammatory models of the rat as well as in the arachidonic acid- and croton oil-induced ear oedema of the mouse. Adjuvant arthritis, experimental pain, skin permeability and allergy models (anaphylactic paw oedema, cutaneous anaphylaxis, asthma, picryl chloride ear oedema) were not, only weakly or irregularly influenced. In the guinea pig ileum a certain antihistaminic, anticholinergic and leukotriene antagonistic activity was found. An inflammation-induced vasodepression (anaphylactic shock, dextran paw oedema. UV irradiation) was dose-dependently prevented or even reversed, obviously on the basis of oxygen radical scavenging.

Adamantane↗
PubMed1989

Neural tolerance of iotrolan 300 in ascending cervical myelography: results of a multicenter study.

This study examined the opacification, dose, and tolerance of iotrolan 300 on 231 patients in ascending cervical myelography. The contrast was rated good in 188 (81.4%) of the cases and satisfactory in 40 (17.3%) of the cases. The contrast was poor in only three (1.3%) cases. In 152 patients a dose of 10 ml or less of iotrolan 300 was administered. A good contrast quality was obtained in 84.2% of all examinations. From a total of 231 patients, 146 exhibited no concomitant effects. The intensity of the headache and neck ache was recorded by the patients themselves by means of an analog scale. The frequency and degree of the postmyelographic complaints did not increase with higher doses, i.e., they were not dose dependent. Neurologic irritation, in the form of radicular symptoms, appeared in only 2 of 231 examinations. These data demonstrate that iotrolan 300 is excellent for use in ascending cervical myelography.

Adult↗
PubMed1989

[Sudden death in a drug milieu following use of an appetite suppressant].

Chemical-toxicological analysis of blood and tissue samples from a drug-dependent person which had been found dead revealed the presence of propylhexedrine. The blood concentration was estimated to be 3.75 mg/l, this value may explain a fatal intoxication. However, death was obviously due to massive blood aspiration from nasal bleeding.

Adult↗
PubMed1989

[Computer tomography of the TMJ versus clinical and instrumental analysis of function].

Data obtained by computer tomography of the TMJ were compared with those of clinical and instrumental analyses of function. 25 females and 37 males aged between 19 and 47 years (mean age, 24.8 years) were examined. None of the patients complained of functional problems subjectively, but clinical analysis of function showed several signs of stomatognathic dysfunction to be present. Results of CT did not correlate with those of clinical and instrumental analysis.

Adolescent↗
PubMed1989

Predictors of functional success in telescopic spectacle use by low vision patients.

Telescopic spectacles can theoretically improve function of low vision patients by enlarging retinal images. However, unintended head movement may produce sufficient instability of enlarged retinal images to negate the visual benefit. We investigated this phenomenon as a cause of failure in 38 low vision patients who had previously attempted use of telescopic spectacles. Patients underwent evaluation of the vestibulo-ocular reflex, visual-vestibulo-ocular reflex, head stability in the pitch and yaw axes, and sensitivity of magnified visual acuity to head motion. Although it was impossible to distinguish successful from unsuccessful telescopic spectacle users by means of clinical or historical data, multiple logistic regression analysis was used to derive a useful predictive function based on measurements of sensitivity of magnified vision to head motion, and head instability in the pitch axis. Predictive performance was found to be superior to conventional clinical judgement. These findings support the hypothesis that retinal image stability is important to functional vision, and suggest that head-stabilizing strategies may improve function with telescopic spectacles in certain low vision patients.

Adult↗
PubMed1989

Adaptation to telescopic spectacles: vestibulo-ocular reflex plasticity.

The vestibulo-ocular reflex (VOR) is a mechanism for the production of rapid compensatory eye movements during head movements. To investigate the adaptation of this reflex to spectacle magnifiers, the effect on the VOR of a brief period of wearing telescopic spectacles during head rotation was studied in normal subjects. VOR gain, as measured in darkness, was defined to be the ratio of compensatory slow phase eye velocity to head velocity. Initial VOR gain as measured for vertical axis sinusoidal head rotation at 0.1 Hz, amplitude 60 degrees/sec, was about 0.7. After 15 min adaptation by sinusoidal rotation during the viewing of a remote video display through X2, X4, or X6 binocular telescopic spectacles, 47-70% of subjects exhibited significant VOR gain increases of 7-46%. These increases were measured with occlusion of the unmagnified visual field peripheral to the telescopes during adaptation. There was considerable interindividual variability in adaptation to telescopic spectacles. Telescopic spectacle power had little or no effect on the amount of VOR change after adaptation, although all telescope powers produced a greater VOR gain change than did adaptation without telescopes. Testing of VOR gain at multiple frequencies indicated that adaptation to telescopic spectacles by rotation at a single sinusoidal frequency induces VOR gain changes across a broad spectrum of frequencies of head rotation. When the unmagnified peripheral visual field was unobstructed during adaptation, VOR gain increases were significantly less than when the unmagnified peripheral visual field was occluded, and were similar to those observed during adaptation without the wearing of telescopic spectacles at all. VOR gain adaptation was associated with amerlioration of symptoms of oscillopsia and motion discomfort initially experienced by about 20% of subjects wearing telescopic spectacles.

Adaptation, Physiological↗
PubMed1988

Occurrence of pharmacologically active benzodiazepines in trace amounts in wheat and potato.

Aqueous acid extracts of wheat grains and of potato tuber were found to contain a series of compounds displaying a high affinity to the central type benzodiazepine receptor (BZR) in mammalian brain. Further analysis using different HPLC systems, as well as mass spectrometry and gas chromatography combined with mass spectrometry lead to the identification of compounds belonging to the classical 5-phenyl-1,4-benzodiazepinones. In wheat grains diazepam, N-desmethyldiazepam, delorazepam, deschloro-diazepam, delormetazepam, lormetazepam and isodiazepam were identified, while potato tuber contained diazepam, N-desmethyldiazepam, delorazepam, lorazepam and delormetazepam. The concentration of the benzodiazepines (BZ) was in the low ppb range. Their biosynthesis most probably takes place in the plant tissue. The availability of BZs in plant nutritives points to a possible source for the previously reported presence of BZ in brain and peripheral tissues of several animal species and man.

Animals↗