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Biomedical subjects

M Bühler

Publications and source records attributed to M Bühler.

At least 19 recordsLinked to original sources
PubMed2007

Gene-gene effects on central processing of aversive stimuli.

Emotional reactivity and regulation are fundamental to human behavior. As inter-individual behavioral variation is affected by a multitude of different genes, there is intense interest to investigate gene-gene effects. Functional sequence variation at two genes has been associated with response and resiliency to emotionally unpleasant stimuli. These genes are the catechol-O-methyltransferase gene (COMT Val158Met) and the regulatory region (5-HTTLPR) of the serotonin transporter gene. Recently, it has been proposed that 5-HTT expression is not only affected by the common S/L variant of 5-HTTLPR but also by an A to G substitution. Using functional magnetic resonance imaging, we assessed the effects of COMT Val(158)Met and both 5-HTT genotypes on brain activation by standardized affective visual stimuli (unpleasant, pleasant, and neutral) in 48 healthy subjects. Based on previous studies, the analysis of genotype effects was restricted to limbic brain areas. To determine allele-dose effects, the number of COMT Met158 alleles (i.e., lower activity of COMT) and the number of 5-HTT low expressing alleles (S and G) was correlated with the blood oxygen level-dependent (BOLD) response to pleasant or unpleasant stimuli compared to neutral stimuli. We observed an additive effect of COMT and both 5-HTT polymorphisms, accounting for 40% of the inter-individual variance in the averaged BOLD response of amygdala, hippocampal and limbic cortical regions elicited by unpleasant stimuli. Effects of 5-HTT and COMT genotypes did not affect brain processing of pleasant stimuli. These data indicate that functional brain imaging may be used to assess the interaction of multiple genes on the function of neuronal networks.

Adult↗
PubMed2004

[False aneurysm of the lateral superior genicular artery. A complication after the implantation of a knee prosthesis].

Arterial complications after total knee arthroplasty are rare. If the formation of a false aneurysm does occur, it usually affects the popliteal artery. We report the case of an 77 year old female with a false aneurysm of the lateral superior genicular artery. The patient was suffering from gonarthrosis and received a duocondylar knee replacement without resurfacing of the patella. Postoperatively, she reported anterior knee pain and a revision of the joint with lateral release was carried out. In the third postoperative week, a painful swelling in the lateral and superior aspect of the knee occurred. A scintigraphic investigation with enrichment in the early period was misinterpreted as infection. Ultrasonographic and angiographic investigations gave the right diagnosis of a false aneurysm. In the same angiographic investigation, the aneurysm could be cured by coil embolisation. The interval between the operation leading to the problem and the formation of the aneurysm, as well as the low incidence of this complication, made it hard to diagnose. Ultrasonographic and angiographic examinations allow for proper diagnosis in cases of unclear painful swellings. When dealing with an arterial complication following total knee arthroplasty, a specialized radiologist or vascular surgeon should be consulted immediately.

Aged↗
PubMed2001

Osteoid osteoma: technique of computed tomography-controlled percutaneous resection using standard equipment available in most orthopaedic operating rooms.

Symptoms of osteoid osteoma are cured by removing the nidus. 'En-bloc' resection is often not successful because the nidus is hard to find and remove totally. Recently, minimally invasive procedures have been advocated for the resection of osteoid osteoma. Preceding investigators have used a set of special instruments. The nidus is best localized with computed tomography (CT). Surgery under CT control is only possible with minimal invasive procedures. A technique using standard equipment usually available in the operating room can be used successfully for CT-guided removal of the nidus. We report our preliminary results with 17 patients (12 men, 5 women) with an average age of 22 years (range 6-57 years). All patients were pain-free immediately after the operation. The average follow-up was 8.4 months (range 1-22 months) and the average operating time 75 min (range 50-130 min). Ten patients could be treated as outpatients. The average time in hospital after surgery was 1.5 days (range 1-3 days). There were two complications, one superficial wound infection and one change of operative technique to an open procedure due to a technical problem. The diagnosis could be confirmed histologically.

Adolescent↗
PubMed2000

The epidemiology of fractures of the proximal femur.

Between 1980 and 1989, reports on 21,145 fractures of the proximal part of the femur (15,428 women and 5,717 men) were collected by AO Documentation and are analysed in the present paper. The number of fractures increases exponentially with age for women and for men. Up to 50, the number of fractures is higher for men than for women and vice versa after 55 years. The exponential increase in the number of fractures with age appears for all the types A1 to B3 for both women and men. No special increase has been identified for women after 50 (expected age of menopause).

Adolescent↗
PubMed2000

The epidemiology of fractures of the distal femur.

Between 1980 and 1989, reports on 2,165 fractures of the distal part of the femur (1,051 women and 1,114 men) were collected by AO Documentation and are analyzed in the present paper. The number of fractures showed a bimodal pattern with a marked variation in the number of fractures in relation to gender and age. A larger prevalence of fractures was observed either in young men (about 20 years old, traffic or sport) and in old women (about 70, fall at home, osteoporosis).

Accidental Falls↗
PubMed2000

The epidemiology of diaphyseal fractures of the tibia.

AO Documentation collected reports of nearly five thousand diaphyseal tibial fractures occurring in the 1980s. The following conclusions can be drawn: i. The number of fractures affecting men is twice that affecting women. ii. These fractures occurred mainly in younger people (under 40 years of age) and no increase occurred in elderly people. iii. Most bending fractures occurred in young men (20-30 yrs) and the torsion fractures affected men and women of about 40 equally. iv. The number of simple fractures (type A) is about the same as for fractures with one fragment (type B).

Adolescent↗
PubMed2000

Novel dialysis cannulas: are they worth the higher price tag?

Accessory hemodialysis equipment, including dialysis cannulas, usually lack controlled and independent testing before being introduced onto the market. The aim of this study is a prospective comparison of a newly designed curved-tip dialysis cannula with a standard dialysis cannula of the same size from the same manufacturer. Fifteen chronic dialysis patients were enrolled onto a prospective 4-month crossover study. All patients had arteriovenous fistulas, except for two patients with polytetrafluoroethylene grafts. The routinely used standard cannulas were replaced by either a curved-tip 15G cannula or a new standard 15G cannula from the same manufacturer. The two cannulas were compared with respect to puncture-related pain and/or problems and bleeding complications, as well as blood-flow dynamics. Venous and arterial access pressures were recorded at blood-flow rates of 100 to 400 mL/min. Linear regression analyses of arterial and venous pressure profiles showed the same regression lines for the standard and curved-tip cannulas. Plasma haptoglobulin levels and occlusion times necessary to stop bleeding after removal of the cannulas did not differ between the two cannulas. Both patients and nurses independently reported equal puncture-related pain and/or problems for both cannulas on visual analogue scales. No correlation was found between puncture problems reported by nurses and puncture pain reported by patients. The curved-tip cannula does not offer an advantage compared with the less expensive standard cannula. Controlled testing of advertised advantages by manufacturers of accessory equipment should be a prerequisite before introduction into routine clinical treatment.

Adult↗
PubMed1998

Longitudinal monthly body measurements from 1 to 12 months of age: a study by practitioners for practitioners. Zurich Association of Practicing Paediatricians.

UNLABELLED: A longitudinal growth study with monthly measurements during the 1st year of life was conducted by nine paediatricians working in private practice in Zurich. Of 92 children, none was lost to the study and only 32 of 1104 planned visits were missed; the quality of the measurements was comparable to that of a specialised university clinic. Compared to the Zurich Longitudinal Growth Studies, children of this study were considerably heavier and taller. In 92% of the subjects, growth velocity was at least once outside the reference range (3rd 97th percentile). For weight increments, the corresponding proportion was 87%. CONCLUSIONS: The data indicate that current standards for the 1st year of life for the Zurich area might no longer be appropriate and need to be updated. The currently used velocity percentiles based on 3-monthly measurements are not suitable to assess individual height and weight increments calculated from monthly measurements.

Anthropometry↗
PubMed1996

Mechanism of the antiischemic effect of mibefradil, a selective T calcium channel blocker in dogs: comparison with amlodipine.

Calcium channel blockers are active in variant angina principally by preventing coronary vasospasm. However, a direct antiischemic effect may also occur. In open-chest dogs, an attack of variant angina was mimicked by a 2-min critical coronary stenosis, and the following reversible myocardial ischemia was assessed by measuring the decrease of segmental shortening. We compared the antiischemic mechanism of mibefradil, a T and L calcium channel blocker, with that of amlodipine, a pure L channel blocker. Both drugs showed a similar relationship between the decrease of the rate-pressure product and the antiischemic effect, but only mibefradil reduced heart rate. Amlodipine and mibefradil at the highest doses tested (20 and 70 micrograms/kg/min, respectively) restored 68 +/- 8 and 76 +/- 5% of segmental shortening in the ischemic area, respectively, as compared with preischemic values. Matching blood pressure (by intraaortic balloon) or heart rate (by atrial pacing) to predrug values showed that the antiischemic effect was mainly afterload-dependent for amlodipine and heart rate-dependent for mibefradil. We conclude that in variant angina, in addition to their antivasospastic effects, calcium channel blockers may be antiischemic by a direct myocardial effect associated with a decrease of the rate pressure product. Blockade of the T channel does not seem to participate in the direct antiischemic effect of mibefradil but could explain the decrease of heart rate.

Amlodipine↗
PubMed1995

[35 years fracture documentation by the Working Group for Osteosynthesis Problems (AO)].

35 years of AO-Documentation has clearly demonstrated the possibilities and the effectiveness of fracture documentation. The fracture classification, x-ray documentation and recommended evaluation scores are essential prerequisites for trend analysis and comparison of results. AO offers today the methodology for a decentralized data collection and scientifically planned clinical trials.

Data Collection↗
PubMed1994

Documentation.

In the period from 1. January to 31. December 1992, the new pinless external fixator was applied in eight European and North American clinics as part of a prospective multicentric study run by the AO/ASIF Documentation Centre. The aim of this study was to determine the indications, handling, and clinical results with the new fixator. The new pinless fixator was used 77 times on a total of 75 patients. The main indications were fresh tibial shaft fractures for which immediate definitive treatment was impossible. The majority of cases were secondarily stabilized with an unreamed tibial nail once the local and/or general condition of the patient had improved. In the remaining cases the pinless fixator was used for calcaneal and tibial head traction, segment transport and temporary stabilization in cases of tibial infection. Only after long-term application of the fixator was local infection at the pin site observed. There were no other complications. The new pinless fixator is a valuable addition in the treatment of fresh tibial fractures, in particular, in those cases which cannot be primarily treated due to contributing factors whether local or general.

Adult↗
PubMed1994

[Clinical results with the limited contact DCP plate of titanium--a prospective study of 504 cases].

From the beginning of 1988 to July 1991, ten Swiss and German clinics undertook to document all cases of internal fixation using the titanium LC-DCP as part of a prospective multicenter study. The follow-up period was 14.2 months on average. The clinical results of 504 fixations were convincing. The follow-up rate was 72%. Of these, 95% healed without complication. The most frequent complication was delayed healing which occurred in 2.5% of cases. The infection rate was low (1.1%). A separate comparison of DCP fixations on the tibial shaft in 1984-1988 demonstrated the obvious biological compatibility of the new plate and shows that excellent results can be obtained using plate fixation.

Adult↗
PubMed1994

[Simultaneous measumrement of the renal excretion of 131I-hippuran and 99mTc-MAG3].

This study describes methods of measuring simultaneously the renal excretion of two radiopharmaceuticals and of evaluating their different kinetics. For quantification of the dynamic contributions of scattered radiation in a double-radionuclide study a high-resolution pure germanium detector was used. The geometry of the arrangement was a semi-shielded whole-body counter according to E. Oberhausen. An intra-individual comparison of the renal elimination of 99mTc-MAG3 and 131I-Hippuran shows a systemic difference between both tracers depending on the time after injection, its average being around 11% between the 10th and 20th min. The inter-individual comparison shows deviations from the mean between -29 and +20%.

Adult↗
PubMed1993

[Classification of proximal femoral fractures].

Based on the AO Classification of Fractures, the classification of fractures of the proximal femur will be explained. Especially the sub- and pertrochanteric fractures, as well as the fractures of the femoral neck will be considered. During the period from 1980-1989 26,126 fractures of the proximal femur were documented in the AO/ASIF Documentation Center. These fractures will be discussed regarding following aspects: dispersion of age and fractures, pre-existing systemic illnesses, general and local postoperative complications, choice of implant.

Aged↗
PubMed1990

[Soft tissue infection--osteitis--osteomyelitis].

Statistically the posttraumatic osteitis shows a clear tendency to decrease from 1972-76 in comparison with 1982-86 (AO/ASIF-documentation). The incidence of infection varies considerably according to the different anatomical location of fractures. More recently atypical manifestations became of more importance and ask for differentiated bacteriological examinations. A close postoperative follow-up and exact wound-observations enable an immediate and adequate therapy in case of an infection.

Bacterial Infections↗