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Biomedical subjects

R Peter

Publications and source records attributed to R Peter.

At least 73 records · Page 4Linked to original sources
PubMed1991

Psychosocial and biobehavioral characteristics of hypertensive men with elevated atherogenic lipids.

Epidemiologic studies demonstrated an excess risk of ischemic heart disease (IHD) among individuals who simultaneously exhibit hypertension and elevated atherogenic lipids (coronary high risk (CHR)-status). Yet, relatively little is known about factors which contribute to the development of CHR-status during early and middle adulthood. The present study explores the role of selected biobehavioral and psychosocial factors in explaining CHR-status using data from a prospective 6.5 years investigation of a cohort of 416 middle-aged (40.8 +/- 9.6 years) male blue-collar workers. Multivariate logistic regression analysis shows that overweight (odds ratio (o.r.) 4.14), smoking (o.r. 2.19), low promotion prospects at work (o.r. 2.71), competitiveness at work (o.r. 2.79) and feelings of sustained anger (o.r. 5.41) independently contribute to the explanation of CHR-status. Furthermore, the operational definition of CHR-status is validated by estimating its power in predicting IHD incidence in the study cohort. In conclusion, co-manifestation of hypertension and elevated lipids is more likely to exist among those blue-collar men who exhibit distinct work-related characteristics in addition to established biobehavioral risks such as overweight and smoking. In view of the high prevalence of CHR-status and of IHD among men in the lower socio-economic strata this finding is also of interest for health policy.

Adult↗
PubMed1990

Phase I trial of 5-fluorouracil, leucovorin, and cisplatin in combination.

The ongoing evaluation of combination chemotherapy with 5-fluorouracil (5-FU) and cisplatin in several tumors prompted a phase I clinical trial of cisplatin with 5-FU modulated by leucovorin. A total of 26 patients were treated with varying doses of 5-FU by continuous i.v. infusion for 5 days; 200 mg/m2 leucovorin was given by daily bolus injection for 5 days; and 20 mg/m2 cisplatin was infused over 2 h on each day of treatment. Courses were repeated every 21-28 days. The starting dose of 5-FU was 300 mg/m2. Poor-risk patients (extensive prior radiation, performance status of 2 or worse) did not tolerate the initial dose; the maximum tolerated dose of 5-FU in this group was 200 mg/m2 daily. Good-risk patients tolerated 300 mg/m2, but a majority had excessive toxicity at higher doses. The dose-limiting toxicity was gastrointestinal (mucositis/diarrhea) and/or myelosuppression; additional side effects included were nausea and vomiting (less than or equal to grade 2) and ataxia (one patient). Among 13 patients with colorectal cancer, 4 partial responses were observed. The marked reduction in the tolerable dose of 5-FU occasioned by the addition of modulating doses of leucovorin is noteworthy. The responses observed support further investigation of this regimen in phase II trials.

Aged↗
PubMed1990

Numerical 3D-stimulation of pulsatile wall shear stress in an arterial T-bifurcation model.

The structure of pulsatile blood flow and wall shear stress in a 90 degrees T-bifurcation model is analysed numerically. The nonlinear Navier-Stokes equations for time-dependent incompressible Newtonian fluid flow are approximated using a newly developed pressure correction, finite element method. The wall shear stress is calculated from the finite element velocity field. The investigation shows viscous flow phenomena such as flow separation and stagnation and the distribution of high and low wall shear stress during the pulse cycle. Furthermore, the effect of a sharp corner at the bifurcation edge on the wall shear stress is analysed. Detailed local flow investigation is required to examine fluid dynamic contribution to the development of arterial diseases such as atherosclerosis and thrombosis.

Arteries↗
PubMed1990

Low status control, high effort at work and ischemic heart disease: prospective evidence from blue-collar men.

An inverse relation between socio-economic class and occurrence of ischemic heart disease (IHD) in advanced societies is an often replicated finding from empirical studies. Yet, the processes which produce these effects remain an open question. One promising explanation concerns the prevalence of stressful working life, especially of distinct 'job strain' occupations. Based on these considerations, we develop a refined concept of work-related socio-emotional distress which considers a mismatch between high workload and low control over occupational status (e.g. job insecurity, poor promotion prospects, status inconsistency) as crucial distress-provoking conditions. Moreover, we assume that the effect of this condition on IHD risk is substantially increased by the presence of a distinct individual pattern of coping with work demand ('need for control'). Based on data from a 6.5 years prospective study on IHD incidence (n = 21) in a cohort of 416 middle-aged blue-collar men this concept is tested using logistic regression analysis. Results indicate that status inconsistency [multivariate odds ratio (o.r.): 4.4], job insecurity (o.r. 3.4), work pressure (o.r. 3,4) and 'need for control' (o.r. 4,5) independently predict IHD occurrence after adjusting for major confounding somatic and behavioral coronary risk factors. In conclusion, a refined model of work-related socio-emotional distress substantially contributes to the explanation of high IHD incidence among blue-collar men.

Adaptation, Psychological↗
PubMed1989

Pulsatile non-Newtonian blood flow simulation through a bifurcation with an aneurysm.

Blood flow is analysed by means of computer simulation in an idealized arterial bifurcation model which is pathologically altered by a saccular aneurysm. The theoretical study of the flow pattern and the paths of fluid particles is carried out under pulsatile Newtonian and non-Newtonian flow conditions. The governing equations are solved numerically with the use of the finite element method. The results show the disturbed blood flow in the bifurcation and the relatively low intra-aneurysmal flow circulation. In addition to the study of basic flow patterns in the segment, a comparison of non-Newtonian and Newtonian results is carried out. This comparison proves that for the considered large artery model under physiological flow conditions where the yield number is relatively low there is no essential difference in the results.

Aneurysm↗
PubMed1988

Wall shear stress distribution in the human carotid siphon during pulsatile flow.

Wall shear stress distribution in the carotid siphon, which is a multiple curved segment of the internal carotid artery, is investigated numerically under physiological flow conditions. The computer simulation of flow through the model segment is based on the time-dependent, three-dimensional Navier-Stokes equations, solved numerically with a finite element method. The study shows the behavior of the wall shear stress-vector field and identifies the zones of high and low wall shear stress values during the cardiac cycle.

Blood Flow Velocity↗
PubMed1988

The prognosis of cranioplasty following large craniectomy in children.

The experience acquired during 10 years treatment of 33 children having undergone a large craniectomy with an average follow-up time of 5.3 years is presented. Different methods of primary and delayed closure of the skull defect are documented and discussed. Whenever possible the deep frozen conserved skull flap was reimplanted. The problem of skull flap resorption and insufficient spontaneous ossification and the alternative of a heterologous cranioplasty with methylmethacrylate (MMA) in cases of insufficient reossification is considered. The decision to use MMA as a secondary skull defect graft should be delayed at least one year after craniectomy, since a spontaneous reossification of the defect is possible until adolescence.

Adolescent↗
PubMed1988

[Frequency and severity of throat complaints following general anesthesia with the insertion of various endotracheal tubes].

Laryngeal and pharyngeal complaints following general anaesthesia are well-known problems. The frequency, extent, and intensity reported in several studies are at variance. Such transient postoperative problems should not be considered equivalent to traumatic airway injuries caused by endotracheal intubation. A decrease in the incidence of slight airway complications was to be expected with the introduction of low-pressure-cuff tubes, however a few studies have reported just the opposite result. This study was designed to investigate the incidence, intensity, and duration of postoperative airway symptoms with special emphasis on cuff construction (low-pressure-high-volume cuff (LPC) vs high-pressure-low-volume cuff (HPC)). Our double-blind study included 500 patients. The acceptance criteria were: operation outside the head and neck region, no throat pack or gastric tube. The subjects were divided randomly into five groups, each group consisting of 100 patients: Group A: red rubber tubes (HPC); Group B: latex-spiral tubes (HPC); Group C: PVC tubes (LPC); Group D: PVC tubes with rediffusion system (LPC); Group E: face mask. The patients of groups A-D underwent oral intubation using lidocaine gel 2%; adequate cuff inflation was determined just after intubation. The patients were questioned every 24 h for 2 days postoperatively using an analogue scale and "open" and "closed" questions. The single groups were comparable in age, sex, height, weight, number of smokers, duration of operation (only groups A-D), and preoperative diseases of the upper airways.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Dose-finding study with bopindolol in arterial hypertension.

Bopindolol is a new beta blocker with a long duration of action which exerts antihypertensive effects at very low dosage. The aim of this study was to define the optimal dosage of bopindolol in outpatients with mild to moderate hypertension and to compare it to atenolol in term of tolerance and efficacy, both administered once daily. Forty physicians (the Swiss Cooperative Study Group) participated as investigators in this study. They had recruited 257 hypertensive patients whose diastolic blood pressure was between 95 and 105 mm Hg (age 19-69 years; mean +/- SD, 49.3/49.9 +/- 10/11) in a multicentric double-blind study. After a 2-week placebo period patients were randomized to one of four treatment groups: bopindolol 1 mg, bopindolol 2 mg, atenolol 50 mg, and atenolol 100 mg. After 4 weeks of active treatment, if diastolic blood pressure was above 90 mm Hg, the dosage was doubled. A detailed evaluation was performed after 8 weeks of active treatment. If necessary, a diuretic was then added and patients were followed for the next 10 months in an open study. Compared to placebo, blood pressure was significantly lowered in the four treatment groups. At 4 weeks, 8 weeks, and 12 months, there was no significant difference between the blood pressures of the treatment groups. Bopindolol was as well tolerated as atenolol. Bradycardia was more common with atenolol. During this 12-month study, bopindolol 1 mg per day appeared to be an effective and a safe antihypertensive treatment. With the exception of the lower incidence of bradycardia, bopindolol is indistinguishable from atenolol in terms of side effects pattern and frequency.

Adrenergic beta-Antagonists↗
PubMed1986

[An uncommon syndrome: the trapped popliteal vein. Apropos of a case].

A case of trapped popliteal vein, an exceptional syndrome, is reported in which the clinical appearance was that of a deep phlebothrombosis, compression being detected on phlebographic images. The etiology (combined congenital malformation and acquired muscle hypertrophy in this case) was revealed during exploratory surgery, which also allowed treatment by excision of the compressing agent without any direct vascular gesture.

Adolescent↗
PubMed1986

Determination of protein C in plasma.

Three new methods to characterize the function of protein C in plasma are described and compared to established procedures. Two methods make use of a snake venom derived specific protein C activator which allows rapid, sensitive and standardizable assays in plasma without sample pretreatment. The other technique is a two dimensional immunoelectrophoresis in the presence of calcium or EDTA, respectively.

Antithrombins↗
PubMed1984

Accuracy and interobserver variability of coronary cineangiography: a comparison with postmortem evaluation.

The accuracy of interpretation of coronary cineangiography by two independent observers was tested against postmortem findings in 27 patients who died within 6 months of cardiac catheterization. Variations in cineangiographic interpretations between the angiographers were also evaluated. Two patients had normal coronary arteries, while the remaining 25 patients had significant coronary artery disease. Significant stenosis was defined as 75% or greater reduction in luminal diameter. Of 326 coronary segments that could be evaluated postmortem, 15% could not be evaluated cineangiographically. The respective overall accuracy of the two observers was 89 and 88% with an accuracy of 96 and 100% for the left main coronary artery, 91 and 93% for the left anterior descending artery, 84 and 86% for the right coronary artery and 89 and 79% for the left circumflex coronary artery. Cineangiographic assessment of luminal status distal to a significant proximal lesion was possible in more than 70% of major vessels with accuracy levels of 86% for both observers. Of 96 distal vessels inadequately opacified cineangiographically, 49 (52%) were found to be free of significant lesions. Both angiographers agreed in their assessment of 86% of the 340 coronary segments. Interobserver agreement was significantly better for the left main, right and left anterior descending coronary arteries than for the left circumflex coronary artery (p less than 0.05). Accuracy was 93% for 244 segments that were adequately opacified and assessed the same by both angiographers. Cineangiography can thus be used to evaluate coronary anatomy with a high degree of accuracy and minimal interobserver variability.

Autopsy↗
PubMed1981

[Parasitic disease in schoolchildren in a village in Swiss Jura].

In a village of the Swiss Jura we examined 134 schoolchildren (7 to 16 years old) clinically, parasitologically and serologically for parasites. Half of the children showed an insufficient hygiene of hands, feet and/or anus. In 7 out of 107 anus-scotch-tests there were eggs of Enterobius vermicularis. Protozoans could be demonstrated in 8 of 133 MIF-stool-samples (2 cases of Giardia lamblia, 2 Endolimax nana and 4 Jodamoeba bütschlii). Using the procedure of enrichment of Telemann no helminth eggs were detected. Altogether parasites were found in 10% of the children. 31 children have antibodies against Toxoplasma gondii (IF titre greater than or equal to 1:40). 5 children showed a positive Toxocara-serology, additional 5 an uncertain positive reaction. The immunodiagnostic of Echinococcosis (ELISA, IF, IHA, CIE) was doubtfully positive in 4 children. In this study, intestinal protozoans and E. vermicularis were the most commonly occurring parasites followed by asymptomatic toxocariasis.

Adolescent↗