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Biomedical subjects

H Hirche

Publications and source records attributed to H Hirche.

173 records · Page 10Linked to original sources
PubMedDate not supplied

Early shunting of 9 microns and 15 microns tracer microspheres from the acutely ischemic canine myocardium.

Recent reports have shown considerably differing results for myocardial shunting of 9 microns and 15 microns tracer microspheres (TMs) under various conditions. This could restrict the use of TMs for myocardial, especially collateral blood flow measurements. To determine the importance of coronary collateral blood flow and its early changes during the first 30 minutes after acute coronary artery occlusion (i.e. the 1st arrhythmic phase), we studied the shunting of 9 microns and 15 microns TMs from the ischemic myocardium during acute LAD ligation. In anesthetized dogs these TMs and subsequently Ringer solution were infused into the occluded coronary artery just distal to the ligation with constant low perfusion pressure. TM shunting (%S) into the lungs was then determined (%S = total lung radioactivity . 100/radioactivity infused). During a single LAD occlusion lasting 35 minutes (series I, n = 10) 9 microns TMs were infused immediately and 30 minutes after ligation, 15 microns TMs being infused after 15-20 minutes. In series II (n = 6) 9 microns TMs were infused immediately during the 1st, short (5 minutes) LAD occlusion. Following 90 minutes of reperfusion a 2nd LAD ligation (35 minutes) was performed with 9 microns TMs being infused immediately and 30 minutes after occlusion. During the first 30 minutes of acute coronary artery occlusion, TM shunting from the ischemic myocardium is negligible for 15 microns TMs (%S less than 0.5%; n = 5), whereas the mean 9 microns TM shunt of the early applied TM (i.e. A1, series I; n = 9; B2, series II; n = 6) amounts to a maximum of 1.21 +/- 0.2% (X +/- SEM). After 30 minutes of occlusion the mean 9 microns TM shunt amounts only to 0.71 +/- 0.15% (i.e. C1, series I; n = 4; C2, series II; n = 4). - In a coronary artery occlusion repeated once, 9 microns TM shunting, while increasing slightly due to the 90 minutes of reperfusion, still amounts to only 1.73 +/- 0.41% (n = 6). In three experiments 9 microns TMs were infused into the unoccluded, normally perfused LCX coronary artery during LAD occlusion. The mean LCX shunt value of 4% after a mean time of 25 minutes following TM infusion is in very good agreement with the 9 microns TM shunt values in the literature. These results clearly demonstrate that the TM technique with 9 microns microspheres is suitable for measuring changes in coronary collateral blood flow at least for a short time period after acute coronary artery occlusion.

Acute Disease↗
PubMedDate not supplied

Changes of extracellular Na+, K+, Ca2+ and H+ of the ischemic myocardium in pigs.

In open-chest pigs during severe myocardial ischemia [K+]e, [Ca2+]e and [H+]e increase, [Na+]e increases transiently reaching control values after 30 min. Extracellular osmolality of the ischemic area increases due to an H2O-shift from the ECS to the ICS. The increase of [Na+]e and [Ca2+]e must b explained by the shrinkage of the ECS due to the H2O-shift. The increase of [Ca2+]e is additionally caused by the decrease of pHe. The increase of [K+]e is mainly caused by the release of K+ from the ICS. The changes of [K+]e and [K+]i cause a decrease of the membrane potential to a range in which slow response potentials and re-entry excitations can occur. The increase of [K+]e therefore seems to be a major factor to cause early post-ischemic arrhythmias.

Animals↗
PubMedDate not supplied

Acute myocardial ischaemia in the anaesthetised pig: local catecholamine release and its relation to ventricular fibrillation.

In anaesthetised open-chest pigs, sequential myocardial samples were obtained before and after occlusion of the distal half of the LAD. These samples were analysed histofluorimetrically to determine the density of catecholamine containing neurones in each sample (quantified morphometrically), and radioenzymatically for total tissue noradrenaline content. Following coronary artery occlusion, 75% of the animals (24 out of 32) died in ventricular fibrillation in the first 30 min, the other 25% (8/32) survived the first 60 min of myocardial ischaemia. Coronary artery occlusion led to a significant reduction in the density of fluorescing fibres in the ischaemic myocardium of animals which fibrillated (from 1.25 +/- 0.2% to 0.67 +/- 0.10% at 15 min) whereas in the survivors there was no significant change in fluorescing area during the course of the experiment. Animals which fibrillated had a significant reduction in tissue noradrenaline concentration of the ischaemic myocardium (from an initial concentration of 612 +/- 72 to 402 +/- 64 ng/g ww) within the first 5 min of ischaemia. It is concluded that in this model of myocardial ischaemia, the development of ventricular fibrillation in the early phase seems to be related to the release of noradrenaline from the sympathetic neurones after the onset of myocardial ischaemia.

Animals↗
PubMedDate not supplied

Health care providers on the World Wide Web: quality of presentations of surgical departments in Germany.

It is becoming increasingly common for health care providers to present information on the World Wide Web (WWW). Patients, as well as health care professionals, do not really know what they can expect today. Many quality criteria are proposed for the assessment of medical Internet sites focusing mainly on structure and content management. The objective of this study was to assess the quality of presentations by health care providers on the WWW and to detect strengths and weaknesses with regard to potential target groups, patients, colleagues, and students. A sample of 171 presentations was randomly selected in March 2000 from a collection of 469 surgical departments in Germany. Medical doctors undergoing a full-time training in medical informatics rated the presentations. A previously evaluated questionnaire was used to assess the presentations with regard to 12 criteria about content and technical features. For each criterion the categories 'very good', 'sufficient', and 'insufficient' could be used. Twenty medical doctors assessed 168 presentations with one to seven valuations per presentation. Three presentations could not be accessed at the time of evaluation. Sixty-eight per cent of the median values of each criterion were rated as insufficient. The only criteria rated sufficient or better in at least 50% were: employees/map, survey of offered medical services, navigation, and layout. University hospitals and heart centres achieved significantly better results than regional hospitals. In conclusion, the quality of provider information on the W WW is unsatisfactory. Most surgical departments do not provide information that could help patients to choose their physicians. The criteria set developed here could be a useful tool for a target-group-oriented self-assessment of provider presentations on the World Wide Web.

Attitude of Health Personnel↗
PubMedDate not supplied

[An epidemiologic study of the pathogenesis of varices. The Bochum study I-III].

A longitudinal study was carried out at 11 secondary schools (Gymnasium) of the city of Bochum to investigate the early and preclinical stages of developing varicose veins. The same pupils were examined when being in the 5th, 9th, and 13th classes (Bochum Study I, II and III). A significant correlation between familial predisposition and the occurrence of varicose veins could not be found until the Bochum Study III. The girls dominated with respect to reticular varices and telangiectasias, the boys with respect to trunk varices, branch varices and incompetent perforators. Photoplethysmography showed shorter refilling times for children and adolescents than for adults, but was not suitable to distinguish between pathological and normal findings. Large varices appeared later than small varices and were preceded by refluxes of the long and short saphenous veins. We thus have for the first time a preclinical sign, which clearly identifies individuals at risk.

Adolescent↗
PubMedDate not supplied

[Preoperative radio-chemotherapy and radical surgery for advanced carcinomas of the oral cavity. 4-year results of a prospective therapy study with DOSAK].

Based on the postoperative data evaluated in September 1989, the results of a regional prospective treatment study conducted by the DOSAK on preoperative radio-chemotherapy and radical surgery for carcinomas of the oral cavity and the oropharynx are presented. In the univariate analysis the histologic lymph node findings after pretreatment, the histologic grading, and the TPI correlated well with the survival rates. The multivariate analysis confirmed that the histologic demonstration of vital tumor cells in the neck lymph nodes after the end of pretreatment is of grat prognostic relevance. The histologic degree of differentiation, the demonstration of vital tumor cells in the primary tumor area after pretreatment and the length of time between radiotherapy and surgery were of secondary importance.

Adult↗
PubMedDate not supplied

[Preoperative irradiation, cisplatin sensitization and radical surgery of primarily operable carcinomas of the oral cavity. Results of a prospective DOSAK treatment study].

165 patients with carcinomas of the oral cavity or oropharynx, clinically appearing operable, were treated between 1985 and 1987 within the framework of a prospective multicenter study. The treatment concept consisted in preoperative irradiation with 32 Gy, cisplatin sensitization with 5 X 20 mg per m2 body surface area and subsequent radical removal of the primary tumor and the regional cervical lymph nodes. Regarding recurrence and survival rates the patient data were analyzed using one- and multi-dimensional statistical methods. The observed survival rates were compared with those assessed with the aid of the treatment-dependent prognosis index TPI (Platz et al. 1982). After 1 years the survival rates under the selected combination therapy were 12% and after 2 years 19% above the assessed survival rates under radical surgery alone.

Cisplatin↗
PubMedDate not supplied

Cervical disk syndromes: value of metrizamide myelography and diskography.

This paper reports on the respective diagnostic values of myelography with water-soluble contrast media and diskography in a study of 100 patients examined between 1979 and 1981 and operated on because of cervical disk disease. The results of the study led to a change of the diagnostic procedures formerly applied in radicular syndromes (i.e., diskography, and then perhaps myelography) and in cervical myelopathy (myelography, rarely followed by diskography). Now cervical metrizamide myelography is always performed first. Diskography is only indicated in radicular syndromes to determine the segment causing clinical symptoms when there is a polysegmental space-occupying lesion on the myelogram in combination with a mono- or oligoradicular neurologic symptomatology; or in the case of a normal myelogram with complaints resistant to conservative treatment.

Cervical Vertebrae↗