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Biomedical subjects

J Vollmar

Publications and source records attributed to J Vollmar.

At least 37 records · Page 2Linked to original sources
PubMed1990

[Biochemical aspects of the evaluation of fixed drug combinations].

Various disciplines have to contribute to the general problem of the evaluation of fixed dose combination drugs, as for instance (clinical) pharmacology, biometry, scientific drug regulations and public health officials. The EC guideline 75/318/EWG and its eludications as well as the German "Arzneimittelprüfrichtlinien" of Dec. 14, 1989 (as referred to in the "Arzneimittelgesetz" of 1986) required that such issues concerning fixed dosage combination drugs must be considered and taken into account. In this framework it is the responsibility of biometry to both to guarantee the use of a valid study design to assure interpretation of the results and to quantify the reliability of pharmacological and clinical considerations. The following paper is concerned with biometrical aspects of the combination drug problem. Basic considerations from a clinical or a pharmacological point of view with respect to the question of whether fixed combination drugs are reasonable or not are not discussed. To support the use of combinations of drugs, a central argument is the improvement of the benefit risk relation compared with that of an adequate monotherapy. Beyond this the fixed combination drugs require additional arguments regarding the enhencement of the safety or the simplicity of the therapy fixing the ratio. It follows that fixed combination drugs have to be supported twice, first with respect to the combination itself, and second with respect to the fixed mixing ratio of its components. The biometrical aspects of the assessment of the gains from (fixed) drug combinations are related to the kind of benefit/risk improvement that is expected. In the first section we discuss some possible types of benefit and risk.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Diurnal lipid and lipoprotein profiles in hypertriglyceridemic patients with bezafibrate and clofibrate.

Thirty hypertriglyceridemic patients were treated under metabolic ward conditions for 10 days with either placebo, clofibrate (500 mg t.i.d.) or bezafibrate (200 mg t.i.d.) in a randomized, double-blind study. In addition, patients received an isocaloric prudent diet. On day 10 a diurnal lipid and lipoprotein profile was carried out. Compliance to medication was good. Each treatment led to significant reductions of fasting triglycerides and cholesterol. Lowering of fasting and integrated diurnal triglycerides was greatest with bezafibrate. HDL-cholesterol profiles were highest with this drug. A strong correlation between fasting and diurnal triglycerides was observed. Triglyceride-lowering therapy must therefore aim at fasting triglyceride values as low as possible.

Adult↗
PubMed1986

Investigations on the exogenous influencing of the spontaneous tumour rate in rats.

72 male and 72 female rats of the strain Can-Hoe-Wiga received standard diet in a long-term study (24 months). A group of equal size received the beta-blocker BM 51.052 administered at a dose of 900 ppm in the feed. The animals in the drug group showed a 20 to 30% delay in body weight gain in comparison with the control animals. These drug-treated animals showed, similarly to experiments with a restrictive diet, a lower death rate, fewer glomerulopathies, and lower creatinine and protein levels in the serum. In addition, there were fewer tumour bearers, the total number of tumours was less, and the malignancy and formation of metastases was reduced. This experiment shows the importance which should be attached to the course of body weight gain during a long-term study. Only if these parameters are taken into consideration, an interpretation of the experimental results is possible.

Animals↗
PubMed1985

Effect of bezafibrate during 4.5 years of treatment of hyperlipoproteinaemia.

Bezafibrate in a dosage of 200 mg 3 times daily was given to 24 patients with type II A (n = 8), II B (n = 1) and IV (n = 15) hyperlipoproteinaemia for 4.5 years. In type II A the content of total cholesterol and that of low density lipoprotein in serum decreased by 10-23 and 11-34 percent over the years compared to pretreatment. In type IV the content of total triglycerides and that of very low density lipoprotein decreased by 28-39 and 38-52 percent, respectively, over the years. High density lipoprotein cholesterol increased in both types. The "atherogenic index" was reduced by the drug. The effect remained through the 4.5 years of treatment. Compliance to the drug was good. Changes in safety laboratory parameters were minor and reversible. No subjective side-effects occurred and no cases of gallbladder disease or cancer were noted. It is concluded that bezafibrate is a safe, convenient and effective serum lipid-lowering drug suitable for the use in primary and secondary prevention of atherosclerotic disease.

Bezafibrate↗
PubMed1985

[Abdominal aortic aneurysm. Change in diagnosis and therapy].

The improved diagnostic approach using computerised tomography and ultrasound investigation resulted recently in a remarkable increase of early diagnosed abdominal aortic aneurysm. Simultaneously in the last decennium the number of elective interventions has been increased 4-6 times. As a result of simplification and standardisation of the operative technique (dissection resp. inlay-technique) the operative mortality for elective surgery has decreased to 1-3%. Statistical datas proved a significant increase of life expectancy for operated patients. Interventions for ruptured abdominal aortic aneurysms are still loaded with a high risk (mortality rate 40-75%). Both elective and emergency vascular repairs should be done by well trained vascular surgeons and should not be a challenge for general surgeons to do sporadic vascular surgery.

Aorta, Abdominal↗
PubMed1985

[Aortofemoral bifurcation bypass--effect of the anesthesia procedure (NLA, thoracic continuous catheter peridural anesthesia) on circulation, respiration and metabolism. Intraoperative circulatory reactions].

51 patients who were selected for aorto-bifemoral bypass operation (infrarenal aortic aneurysm, iliac or iliofemoral occlusive disease) were randomized into two groups. 26 patients were operated on under neuroleptanaesthesia and 25 patients had a continuous thoracic epidural, which was supplemented with a light general anaesthesia during the operation. All patients were optimally volume loaded prior to surgery. The most marked haemodynamic alterations (tachycardia, arterial hypertension, increase of cardiac index, left ventricular stroke work index and cardiac minute work) were provoked by eventration of the gut. In the epidural group, these changes were attenuated and in contrast to the neuroleptanaesthesia group, there were a few patients who had a serious fall in blood pressure. These reactions were regularly accompanied by a generalized flush which led to the hypothesis that they were caused by the release of intestinal hormones, reactive peptides and neurotransmitters, from the mechanically irritated gut. Clamping of the aorta was relatively uneventful. Heart rate and cardiac index decreased in both groups but mean arterial pressure and pulmonary capillary wedge pressure remained stable. Systemic vascular resistance increased slightly in the neuroleptanaesthesia, but not in the epidural group. Declamping was followed by significant but transient falls in systemic vascular resistance and arterial pressure in both groups, despite sufficient volume loading before opening the clamp. In the neuroleptanaesthesia group these changes spontaneously returned to normal; in the epidural group 6 patients received vasopressors or positive inotropic drugs. These results indicate the following: Epidural anaesthesia prevents hypertension and tachycardia and lowers cardiac minute work. Eventration of the gut, acute blood losses and declamping of the aorta may be critical situations, which can lead to profound hypotension. Under neuroleptanaesthesia eventration of the gut is followed by tachycardia and hypertension whereas blood losses and declamping are not as critical as when an epidural is used. Only experienced anaesthetists should use epidural anaesthesia for aortic surgery. An intensive monitoring of haemodynamic function during this form of anaesthesia is mandatory.

Adult↗
PubMed1985

Diurnal lipid and lipoprotein profiles with bezafibrate and clofibrate in healthy volunteers.

Diurnal lipid and lipoprotein profiles were measured in 28 healthy volunteers after 10-day treatment periods with placebo, bezafibrate (200 mg 3-times daily) or clofibrate (500 mg 3-times daily) in a double-blind, parallel trial. The two drugs lowered fasting triglyceride and cholesterol levels (p less than or equal to 0.05 for cholesterol with bezafibrate vs placebo). Diurnal triglyceride profiles were lowest with bezafibrate due to lowest fasting triglycerides. Alimentary lipaemia with placebo was mild and due to increased VLDL-triglycerides, while the other lipoprotein lipids and total plasma cholesterol remained virtually unchanged during the day. Bezafibrate (half-life 2 hours) and clofibrate (half-life 15 hours) gave similar diurnal triglyceride patterns. The diurnal values were dependent on the fasting values. Changes in the cholesterol/phospholipid ratio during the day may be related to altered post-prandial composition of HDL.

Adult↗
PubMed1984

The influence of age and multimorbidity on the pharmacokinetics and metabolism of spironolactone.

The pharmacokinetics of the metabolites of spironolactone (canrenone and fluorigenic metabolites) were investigated in 10 geriatric female patients with multimorbidity after a multiple daily oral administration of 100 mg spironolactone under steady state conditions. The concentration determinations were carried out simultaneously with a specific HPLC method and a less specific fluorimetric method. On comparison of the pharmacokinetic parameters with the respective values of a control group of younger healthy female subjects, the serum concentrations in the elderly patients were found to be twice as high. In addition, a statistically significant positive correlation with age was found in the patients for the kinetic parameters investigated. A positive correlation existed between erythrocyte count and the pharmacokinetic parameters of canrenone, especially with the area under the concentration/time curve. No such association was detectable, however, for the total fraction of fluorigenic metabolites (including canrenone). The results of our investigation indicate that, in addition to the known high binding of canrenone to plasma proteins, there is also possibly a (restrictive) binding to erythrocytes.

Aged↗
PubMed1983

Criteria for the standardization of Salmonella mutagenicity tests: results of a collaborative study. IV. Relationship between the number of his- bacteria plated and number of his+ revertants scored in the Salmonella mutagenicity test.

Five laboratories participated in a joint ring study to investigate the role of bacterial cell number in the Salmonella mutagenicity test. A strictly standardized protocol, using sodium azide and TA 1535, was developed and employed to test the mutagenicity of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) with different dilutions of Salmonella typhimurium TA-100 and TA-1535 cultures. All laboratories detected the mutagenic activity of sodium azide with only a 2-fold variation of test results. For MNNG the interlaboratory variation was approximately 5-fold. Decreasing numbers of test bacteria employed resulted in lower numbers of MNNG-induced revertants in all laboratories. The number of preexisting revertants decreased in direct proportion to the reduced cell content, whereas the number of spontaneous revertants was not as greatly affected. A critical amount of test bacteria was required in order to obtain numbers of induced revertants which were equal to twice the number of spontaneous revertants. Two evaluation parameters which may be employed to describe the mutagenicity of a compound are compared.

Animals↗
PubMed1983

[Thromboembolism prevention in surgical medicine: heparin or heparin-dihydroergotamine?].

This review summarizes clinical studies on prevention of venous thromboembolism by heparin or heparin and dihydroergotamine. Advantages and disadvantages of both drugs are described. The value of low-dose-heparin can no longer be seriously disputed. Up to now, however, there is no clear evidence that heparin-dihydroergotamine improves the efficacy and reduces the frequency of complications. The later drug is a new approach still under investigation.

Clinical Trials as Topic↗
PubMed1983

Guar gum and bile: effects on postprandial gallbladder contraction and on serum bile acids in man.

In a randomized cross-over study, 10 healthy volunteers received a fiber-depleted liquid mixed meal alone and, exactly 7 days apart, a combination with 15 g guar gum. Addition of the dietary fiber inhibited emptying of the gall bladder after 30 min to 7 (5-10) ml instead of 4 (3-6) ml (p less than 0.05) and delayed its refilling. Also the postprandial increase in conjugated serum bile acids was prevented by guar gum. The maximal postprandial blood glucose 30 min after ingestion of the meal was reduced from 120 (117-135) mg/dl to 110 (105-119) mg/dl (p less than or equal to 0.05) by guar gum. Serum insulin levels were unaffected by guar gum.--Our data suggest that the addition of guar gum to meals affects enterohepatic circulation of bile acids as well as digestion of carbohydrates.

Adult↗