Search PubMed⌕ Search

Biomedical subjects

M Beyer

Publications and source records attributed to M Beyer.

At least 55 records · Page 3Linked to original sources
PubMed1998

Quality circles in ambulatory care: state of development and future perspective in Germany.

OBJECTIVE: To survey the quantitative development of quality circles (peer review groups; QC) and their moderators in ambulatory care in Germany, to describe approaches to documentation and evaluation, to establish what types of facilities and support is available and to assess opinions on the future importance of QC. DESIGN: Cross-sectional survey using a standardized questionnaire and supplementary telephone interviews. SETTING: All 23 German regional Associations of Statutory Health Insurance Physicians (ASHIP) were surveyed. RESULTS: The total number of QC in ambulatory care in Germany increased rapidly from 16 in 1993 to 1633 in June 1996, with about 17% (range 1.0-52.1%) of all practicing physicians (112 158) currently involved. Throughout Germany, 2403 moderators were trained in 168 training courses by the qualifying date. Follow-up meetings were held or being planned in 20 ASHIP, with approximately 39% (23-95%) of the moderators participating. Systematic documentation of QC work was undertaken or planned in all 23 ASHIIP, and 10 ASHIP carried out comparative evaluation, with at least five others planning to start it. The ASHIP promoted the work of QC by providing organizational (22) or financial (20) support, materials (20) or mediation of resource persons (16). Eleven ASHIP received grants from drug companies. ASHIP rated the future importance of QC as increasing (18) or stable (four), but in no case as decreasing. CONCLUSIONS AND RECOMMENDATIONS: The quantitative growth of QC in Germany is encouraging, but the extent of support and evaluation appears insufficient. Increased methodological support and facilitation, follow-up meetings on a more regular basis, improved documentation and evaluation of individual QC, and problem oriented evaluation of their impact on health care are essential for further successful development. Principles, problems and solutions discussed may be relevant for similar QI activities in other countries.

Ambulatory Care↗
PubMed1997

[Cardiomyopexy--current status of an indirect revascularization method].

From May 1993 to September 1995, six patients underwent a new myocardial revascularization procedure. These patients were not suitable for direct coronary artery surgery due to diffuse and peripheral coronary stenosis and severe angina pectoris (NYHA classes III-IV). Thus, indirect myocardial revascularization or cardiomyopexy was performed. This consists in the grafting of a free skeletal muscle flap onto the ischemic heart. After harvesting the musculus latissimus dorsi as a free flap, the graft was transplanted onto the heart. The arterial stump of the muscle flap artery was implanted directly into the aorta, venous flow was drained into the right atrium. There to four weeks after the intervention the patients were free from angina. Ischemic ST-segment changes appearing preoperatively at 50 W disappeared 8 weeks later even at a higher exercise tolerance. The two patients that underwent the intervention in 1993 and 1994 are still free from angina. In the present work experimental and clinical experiences with indirect myocardial revascularization are summarized and discussed.

Angina Pectoris↗
PubMed1996

[Evidence based medicine, the Cochrane Collaboration and dealing with medical literature. Implications for medical education, graduate and continuing education].

The concept of evidence-based medicine yields to provide medical practice with actual scientific evidence, which raises from a comprehensive analysis of randomized controlled studies. The article reviews recent approaches, especially in the field of primary care (resp. family medicine) and points out the various outcomes of this concept within an analysis of the German system of medical instruction and continuing education. This approach, as all other components of medical education, shall prove its efficacy in further studies evaluating the impact on achievement in patient's care.

Curriculum↗
PubMed1996

[Initial clinical experiences with indirect myocardial revascularization--free skeletal muscle transplantation for induction of epimyocardial neovascularization].

Patients with multiple and peripherial coronary stenosis are not suitable for direct coronary artery surgery. For these patients a new surgical myocardial revascularization was developed. This new surgery was adopted on 5 patients from May 1993 through May 1995. The operation consisted in the grafting of a free skeletal muscle flap onto the anterior wall of the heart (musculus-latissimus-dorsi). The flap artery was implanted into the aorta, the venous flow was directed into the right atrium. All patients were about 3 weeks after the intervention free from angina. The postoperative bicycle ergometry showed no signs of ischemic ST-segment changes, meanwhile the preoperative ergometry evinced signs of ischemic ST-segment changes in almost all patients. Angiographically a patent anastomosis of the flap artery implanted into the aorta was found as well as a good contrast of the graft. Thus, "indirect myocardial revascularization" may be a surgical alternative treatment for patients suffering from therapy refractory ischemic heart disease.

Aged↗
PubMed1995

[Energy and nitrogen metabolism of pregnant and lactating sows and suckling piglets. 6. Comparative studies of energy and nitrogen metabolism of non-pregnant and pregnant sows].

Aim of the studies was to attain new scientific findings for the influence of the physiological state of sows (non-pregnant and pregnant respectively) on energy and nitrogen metabolism. The experiments were carried out according to a 3 x 3 factorial experimental plan with 3 variants of litter number (1, 2 and 4) and 3 variants of energy supply (120, 100 and 80%). Within the variants the non-pregnant and pregnant sows were fed equally related to the metabolic live weight. The metabolism measurements run from the 1st to the 115th experimental and gestation day respectively. The methods of indirect calorimetry and slaughtering technique were applied. The chemical composition of the whole bodies of the non-pregnant sows was like that of the maternal bodies of the pregnant sows (dry matter 410 g/kg, protein 160 g/kg and fat 210 g/kg). The physiological state for the sows did not influence the nutrients digestibility (OM 77.0 and 76.7%) and the energy metabolizability. About conformable intakes of metabolizable energy (601 and 586 kJ/kg LW0.75.d) and of digestible nitrogen (0.77 and 0.75 g/kg LW0.75.d) in non-pregnant and pregnant sows resulted in higher deposition of energy (64 and 79 kJ/kg LW0.75.d) and of nitrogen (0.15 and 0.19 g/kg LW0.75.d) in the pregnant sows due to energy and nitrogen deposition in the conception products and in the reproductive organs. The energy maintenance requirement and the partial efficiency of the energy utilization for the deposition as well as the nitrogen maintenance requirement and the partial efficiency of the nitrogen utilization for the deposition in the non-pregnant and the pregnant sows were determined.

Animals↗
PubMed1995

[Energy and nitrogen metabolism of pregnant and lactating sows and suckling piglets. 7. Energy and nitrogen metabolism in suckling piglets].

In 23 litters, each with 10 or 11 piglets, the energy and nitrogen metabolism was measured on base of 218 body analyses in suckling piglets and on base of 96 total metabolism experiments in early weaned piglets, combined with 134 body analyses. The studies were carried out as part of a complex experimental program for the factorial derivation of energy and protein requirement of piglets and for measuring the milk production of lactating sows. The energy maintenance requirement of suckling piglets (sow's milk nutrition, I) and of early weaned piglets (sow's milk replacement on the basis of cow's milk, II) amounted to 468 (I) and 451 kJ (II) metabolizable energy per kg LW0.75 . d, the utilization of of metabolizable energy for energy deposition to 70(I) and 72% (II). With mean live weight gains (LWG) of 161 and 162 g per animal and day the cost per kg LWG amounted to 19.9 and 20.4 MJ gross energy, 19.3 and 19.4 MJ metabolizable energy as well as 14.4 and 14.2 MJ net energy-fat in suckling and early weaned piglets resp. The mean energy content of the LWG amounted to 8.9 (I) and to 7.9 MJ/kg (II).

Animals↗
PubMed1994

Indirect myocardial revascularization--an experimental study in the dog.

It has been shown in previous studies that grafting a free skeletal muscle flap onto the heart of the dog produces myocardial revascularization. In order to evaluate the functional aspect of these neovessels, an Ameroid constrictor was implanted into the LADs (left anterior descending coronary artery) of five dogs. At the same time, the free muscle flap was grafted onto the anterior wall of the heart. The arterial anastomosis was achieved with the internal mammary artery. Venous flow was drained into the right atrium. About 12 months later, the regional myocardial blood flow was evaluated adopting the radioactive microsphere technique. This was carried out with the LAD occluded by the Ameroid constrictor and the circumflex artery (CX) open (control conditions). Then the CX was occluded in order to exclude collateral blood flow. Afterwards another occlusion of the CX was performed ("preconditioning") to produce maximal opening of the anatomical collaterals. It was found that regional myocardial blood flow was unchanged in the antero-lateral parts of the hearts despite complete occlusion of the coronaries supplying this area. In the parts supplied by the CX, though, flow was minimal. "Preconditioning" positively influenced the perfusion of this region only in the epicardial parts. Histologically large sinusoid-like blood conductors connected the graft and the heart. Thus, grafting a free skeletal muscle flap onto the heart in the dog produces functional myocardial revascularization in the dog.

Anastomosis, Surgical↗
PubMed1994

Influence of intravenous calcium gluconate on saphenous vein graft flow in closed-chest patients.

The effects of calcium gluconate on hemodynamics and saphenous vein graft flow in a group of patients undergoing elective coronary artery bypass grafting who developed ionized hypocalcemia at the end of the surgical procedure were examined. The patients received a central venous bolus of 15 mg/kg of calcium gluconate. Heart rate (HR), arterial pressure (AP), central venous pressure (CVP), pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP), and cardiac output were measured immediately before and 30, 60, 120, 180, and 240 seconds after injection of calcium gluconate. Systemic and pulmonary vascular resistance (SVR and PVR, respectively), cardiac index (CI), stroke volume index (SVI), and right and left ventricular stroke work index (RVSWI and LVSWI, respectively), were calculated. Venous bypass flow velocity (Vbypass-flow) was assessed using a Doppler probe that was attached to the left anterior descending artery (LAD) bypass intraoperatively. Calcium gluconate significantly increased MAP, SVR, and LVSWI from 67 +/- 3 mmHg (mean +/- SEM), 1,128 +/- 128 dyne.s.cm-5 and 25 +/- 3 g.m.beat/m to a maximum of 81 +/- 5 mmHg (P < 0.01), 1,401 +/- 196 dyne.s.cm-5 (P < 0.05), and 32 +/- 4 g.m/beat/m (P < 0.01), respectively. HR, CVP, PAP, PCWP, PVR, CI, SVI, and Vbypass-flow remained unaltered. It is concluded that calcium gluconate administered to moderately hypocalcemic patients increases arterial pressure mainly by peripheral vasoconstriction. Because the increase of arterial pressure, and, thereby, coronary perfusion pressure is not associated with an increase of LAD bypass flow, vasoconstriction in the coronary vascular bed distal to the venous graft cannot be ruled out, and deterioration of the myocardial oxygen supply/demand ratio is strongly suggested.

Aged↗
PubMed1994

[Energy and nitrogen metabolism of pregnant and lactating sows in addition to the suckling piglets. 4. Chemical composition and energy content of the conception products, reproductive organs and the live weight gain or loss in pregnant or lactating sows].

The chemical composition and the energy content of the conception products, the reproductive organs and the live weight gains or losses of pregnant and lactating sows were determined in dependence on the litter number (1, 2 and 4) and the energy supply (120, 100 and 80% of requirement recommendation) of sows as well as on the course of gestation and lactation. The results will be used as a basis for factorial derivation of requirement recommendation. The deposition of protein and energy in the conception products in dependence on the time is characterized by an exponential function. The deposition of nutrients and energy in the conception products is increased with rising litter size. The deposition of nutrients and energy per fetus is lower in the litter number 1 than in the litter number 2 and 4. The energy supply in the selected limits has no significant influence on the litter size as well as on the intrauterine deposition of nutrients and energy. The litter number, the energy supply as well as the course of gestation and lactation influence considerably the weight, the chemical composition and the energy content in the mammary gland. The chemical composition and the energy content of the live weight gains or losses of pregnant and lactating sows are strong affected by the energy supply. The increased energy supply of the pregnant sows is connected with increased live weight gains and with increased contents of dry matter, fat and energy however decreased contents of protein in the live weight gains. The live weight losses of the lactating sows are connected with mobilisation of body fat and body protein. The proportion of body fat to body protein degradation is increased with increased losses of body weight. Regression equations are calculated for the relationships between course of gestation and lactation respectively and deposition of protein and energy in the conception products, reproductive organs and maternal live weight gains or losses of sows.

Animals↗
PubMed1994

[Energy and nitrogen metabolism of pregnant and lactating sows and suckling piglets. 5. Energy and nitrogen metabolism of pregnant sows].

The energy and nitrogen metabolism of pregnant sows was measured with the method of indirect calorimetry in dependence on the number of gestation (1,2 and 4), on the energy supply (120, 100 and 80% of the requirement recommendation) and on the gestation stage. Values of maintenance requirement and of energy and nitrogen utilization for body deposition were calculated on the basis of results of energy and nitrogen metabolism. The energy maintenance requirement increased from 389 to 435 and 473 kJ metabolizable energy per kg LW0.75.d with rising number of gestation. The heat production increased from 85th to 115th day of gestation by 6%. The efficiency of the partial energy utilization for the energy deposition amounted to 66% on the average. The efficiency of the partial utilization of digestible nitrogen for the nitrogen deposition was calculated to 75%. The nitrogen maintenance requirement values amounted to 0.5 and 0.4 g digestible nitrogen per kg LW0.75.d in the 1st and 2nd half of gestation.

Animal Feed↗
PubMed1994

Influence of phenylephrine bolus administration on left ventricular filling dynamics in patients with coronary artery disease and patients with valvular aortic stenosis.

BACKGROUND: Left ventricular diastolic function is known to be impaired in patients with coronary artery disease and patients with valvular aortic stenosis. Phenylephrine is frequently administered as an intravenous bolus in these patients perioperatively to increase coronary perfusion pressure. Although this is common practice, there is no information about the effect of phenylephrine bolus administration on left ventricular filling dynamics. METHODS: Twenty patients with coronary artery disease (group 1), 15 patients with valvular aortic stenosis (group 2), and 10 subjects without cardiovascular disease (group 3, control) entered the study. Left ventricular filling was evaluated using transesophageal pulsed Doppler echocardiography before and after phenylephrine injection given to patients whose mean blood pressure has decreased by more than 20% (and was not higher than 90 mmHg). We recorded the transmitral blood flow velocity curve and measured peak early and peak atrial flow velocity, acceleration and deceleration time of the early flow velocity peak, and mitral valve diameter. We calculated the ratio of peak early to peak atrial flow velocity (PE/PA), acceleration and deceleration rate of the early flow peak, and peak filling rate. RESULTS: Phenylephrine effectively restored arterial pressure in all three groups. However, in group 1, phenylephrine administration resulted in a reduction of PE/PA, acceleration rate of the early flow peak, and peak filling rate from 1.25 (mean) to 0.75 (P < 0.001), 411 to 276 cm/s2 (P < 0.001), and 439 to 305 ml/s (P < 0.001), respectively. In contrast, in group 2, intravenous phenylephrine increased PE/PA, acceleration rate of the early flow peak, and peak filling rate from 0.76 to 0.97 (P < 0.001), 365 to 503 cm/s2 (P < 0.05), and 321 to 388 ml/s (P < 0.01), respectively. In the control subjects, phenylephrine caused a transient reduction of PE/PA and peak filling rate from 1.71 to 1.39 (P < 0.001) and 618 to 524 ml.s-1 (P < 0.001), respectively. CONCLUSIONS: Phenylephrine bolus administration causes an alteration of left ventricular filling in coronary artery disease patients that seems to be more marked than that seen in normal subjects. In patients with aortic stenosis no deleterious effects were observed in response to phenylephrine.

Adult↗
PubMed1994

[Comparison of the negative inotropic properties of nifedipine and nisoldipine using isovolumetric contractile parameters of the rat in vivo].

The vasoselectivity of new dihydropyridine calcium antagonists is much higher as compared to their prototype substance nifedipine. To investigate whether an equihypotensive dose of a new dihydropyridine has less negative inotropic properties in an intact circulation, nifedipine (NIF) and nisoldipine (NIS) were infused intravenously in an open-chest, anaesthetized rat model. The maximal isovolumic left ventricular pressure (LVPiso) and the maximal isovolumic rate of change of LV-pressure (dp/dtmaxiso) were determined to achieve load independent parameters of LV contractility. To evaluate the effect of the infused volume, the stability of the preparation and the hemodynamic effects of the drug-solvent, two groups with either infusion of isotonic NaCl-solution or 20% ethanol served as controls. NIF and NIS were infused in three equihypotensive doses within 7 min (NIF 250, 500, 1000 micrograms/kg; NIS 12.5, 25, 50 micrograms/kg). The decrease of the peripheral resistance of these doses was 74 +/- 6, 67 +/- 6, and 58 +/- 7% for NIF, and 78 +/- 7, 65 +/- 8, and 56 +/- 7% for NIS (p < 0.001 for all groups). In the control groups the afterload remained unchanged. NIF-infusion resulted in a dose-dependent decrease of LVPiso at the end of the infusion period (in percent of controls: NIF250 88 +/- 3%, p < 0.001; NIF500 74 +/- 3%, p < 0.001) as well as 15 min after the end of the infusion. In the same way dp/dtmaxiso decreased significantly after NIF at the end of infusion (NIF 250 82 +/- 6%, p < 0.001; NIF500 61 +/- 8%, p < 0.001) and 15 min after the end of the infusion. After NIS-infusion the contractility parameters decreased slightly after the higher dosage (25 micrograms/kg) at the end of the infusion period only (LVPiso 96 +/- 3%, p < 0.01; dp/dtmaxiso 93 +/- 5%, p < 0.01). There was no depressive effect on the isovolumic contractility parameters at the end of infusion of the lower dosage and 15 min after the drug-infusion of all dosages of NIS. Therefore, nisoldipine, as an example of a new dihydropyridine, has significantly less negative inotropic properties over a wide range of doses as compared to nifedipine in equihypotensive doses.

Animals↗
PubMed1993

Free skeletal muscle transplantation to an infarction area: an experimental study in the dog.

In plastic surgery, free skeletal muscle flaps are used for treatment of non-healing injuries like chronic osteitis or radiation ulcers. We wanted to evaluate if the neoangiogenesis induced by these flaps can also constitute a method for revascularization in ischemic heart disease. In diffuse small vessel coronary heart disease, patients are not suitable for bypass surgery because it is impossible to create a microanastomosis with the coronary artery. As an alternative, a free striated muscle flap, transplanted onto the heart, can constitute a source of neovessels. With the induction of extra-intracardial collaterals that develop within 4 weeks after transplantation of the flap, a new surgical approach may be offered to those patients. Our experimental work was performed with 20 dogs. In these, a myocardial infarction of the anterior wall was selectively produced using the Judkins-technique (Radiology 89: 815-824, 1967) for injection of Sephadex-microspheres. Four weeks later a free pectoralis muscle flap was transplanted onto the anterior wall of the heart. Arterial blood supply was achieved with an anastomosis with the internal mammary artery. The venous flow was directed into the right atrium. Four to eight weeks after surgery, the patency of the anastomosis was studied by angiography, showing patency in almost all surviving animals. Histological examination of the hearts revealed a prominent vascular network penetrating into the underlying myocardium. Corrosion cast preparations, as well as a postmortem angiography, showed even further penetration of the neovessels into the uninjured parts of the myocardium. Thus, myocardial revascularization may be achieved by transplantation of a skeletal muscle onto the heart.

Anastomosis, Surgical↗
PubMed1993

Thromboxane--co-factor of pulmonary disturbances in intramedullary nailing.

UNLABELLED: Pulmonary complications during and after intramedullary nailing particularly in trauma patients have directed clinical interest to thromboembolic events and metabolic alterations, as found in different methods of fracture stabilisation. In 30 patients (mean age 34 years) isolated, closed or 1 degree open fractures of the tibia were operated on in three groups with reamed nailing (RN; n = 11), unreamed nailing (UN; n = 11) and external fixation (EF; n = 8) respectively. In blood samples of the femoral vein of the fractured limb, a 5-7 fold increase of the thromboxane (TXB2) concentration was found in all patients. However, differences of TXB2 concentrations in the arterial blood after passage of the lungs were conspicuous. The highest arterial TXB2 concentrations were found in connection with RN, followed by UN and finally EF. The transpulmonary TXB2-clearance displayed the following relationship: EF > UN > RN (5.7:4,4:2.2). A similar correlation was found for PGF2 alpha while other arachidonic acid metabolites showed no significant behaviour. TXB2 and PGF2 alpha cause bronchoconstriction, pulmonary vasoconstriction and aggregation of thrombocytes. These pulmonary disturbances may results in ARDS, a feared complication after intramedullary nailing. CONCLUSION: Early fracture stabilisation particularly in severely injured patients is an established procedure. To prevent pulmonary disturbances the external fixator is preferrable to the UN and finally the RN. Our data suggest that for the prevention of pulmonary disturbances EF is superior to UN and RN.

Adolescent↗
PubMed1993

[The effect of starch sources barley, corn and potatoes and their ration proportions on nutrient digestibility and energy utilization in ruminants. 2. Fractions of ruminally and postruminally digested nutrients in cattle].

The investigations of this paper are part of a complex research project to develop energetic feed evaluation within the Net Energy Fat System. The aim was to obtain new results to estimate the relation between place as well as kind of nutrient digestion and energetic utilization of rations in cattle. The ruminal nutrient digestibility was measured in adult oxen on feeding level 1.7 by means of duodenal reentrant cannula for 9 rations including the starch sources barley, maize and potatoes and with their energy parts of 50, 25 and 10%. The intake of starch ranged from 484 to 2573 g/animal.d and the amounts of ruminal and postruminal digested starch from 444 to 2336 as well as 10 to 284 g/animal.d. For the organic matter, starch, water soluble carbohydrates and N free residual substances high relative parts of ruminal digested from apparent digested nutrients were measured with values between 78 and 88, 83 and 98, 93 and 97 as well as 88 and 100% respectively.

Animal Feed↗
PubMed1993

[Comparative studies of the parameters of rumen fermentation and the digestibility of feed rations in cattle and sheep. 2. The digestibility of feed rations].

The results from 283 comparisons of digestibility in cattle (ox, cow, male and female young cattle) and sheep (adult wether) are presented. The crude protein content of the applied rations ranged from 90 to 340 and the crude fibre content from 80 to 430 g/kg DM. Within the range of rations with 200-350 g crude fibre per kg DM the differences between adult cattle and wether in the digestibility of energy and organic matter don't exceed 1%-unit (mean -0.5 +/- 2.5), that of crude protein is 5%-units lower in adult cattle than in adult wether. In young cattle digestibility is altogether lower than in wether; in young cattle with 120 to 200 kg live weight 4 to 6 and in more developed cattle 3 to 4 digestibility units for energy. In the metabolizability of the energy in comparison between adult wether and the different animal categories of cattle the difference don't exceed 1.5%-units. Relations between the live weight of cattle, the crude fibre of the rations as well as the nutrition level and the amount of difference of digestibility between cattle and sheep are considered.

Age Factors↗