Biomedical subjects

M Kuster

Publications and source records attributed to M Kuster.

15 recordsLinked to original sources

PubMed2005

First results from the CERN axion solar telescope.

Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by the Primakoff process. In a laboratory magnetic field ("axion helioscope"), they would be transformed into x-rays with energies of a few keV. Using a decommissioned Large Hadron Collider test magnet, the CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling g(agamma)<1.16x10(-10) GeV-1 at 95% C.L. for m(a) less, similar 0.02 eV. This limit, assumption-free, is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment over a broad range of axion masses.

Journal Article↗

PubMed1999

Whipple endocarditis without overt gastrointestinal disease: report of four cases.

BACKGROUND: Cardiac manifestations of Whipple disease are rarely diagnosed before death. OBJECTIVE: To describe four patients with endocarditis caused by Tropheryma whippelii who did not have overt gastrointestinal disease. DESIGN: Case series. SETTING: Five hospitals in eastern Switzerland. PATIENTS: Three men and one woman undergoing replacement of insufficient heart valves. MEASUREMENTS: Histologic characteristics of heart valves and intestinal biopsy; broad-range and specific polymerase chain reaction for T. whippelii. RESULTS: Tropheryma whippelii was found in the heart valves (three aortic valves and one mitral valve) of four patients with culture-negative endocarditis necessitating valve replacement. All patients had arthralgia for different lengths of time. Only one patient had mild gastrointestinal symptoms. Histologic characteristics of intestinal mucosa were normal in all patients, and polymerase chain reaction on intestinal biopsy was positive for T. whippelii in only one patient, who did not have diarrhea. In all patients, arthralgia resolved promptly after institution of antibiotic therapy. Disease did not recur in any patient after prolonged antibiotic therapy with cotrimoxazole. CONCLUSION: In patients with culture-negative endocarditis, the absence of clinical, microscopic, or microbiological evidence of gastrointestinal disease did not rule out T. whippelii.

Actinobacteria↗

PubMed1999

The benefits of wearing a compression sleeve after ACL reconstruction.

PURPOSE: It was the purpose of the present study to examine the possibility of increased muscle coordination after anterior cruciate ligament (ACL) reconstruction through the wearing of a compression sleeve. METHODS: Thirty-six patients were studied who had undergone unilateral ACL reconstruction at least 12 months previously. All subjects were required to perform a 10-cm standing drop jump from an elevated platform onto a force plate, to land on one leg, and thereafter maintain a one-legged balance for 25 s. This task was repeated three times without and three times with an elastic compression sleeve worn on the reconstructed limb. For analysis, the task was partitioned into a landing phase (150 ms), an adjusting phase (10s), and a balancing phase (10s). The peak impact loadings were measured in each direction (Fx, Fy, and Fz) during landing, while force-time integrals (intFz, intFy, and intFz) and root mean square (RMS) error of these forces were calculated for the adjusting and balancing phases. The path length and RMS of the center of pressure coordinates (Ax and Ay) were obtained for the adjusting and balancing phases combined. RESULTS: Drop landings with the bandage produced significantly larger (P < 0.001) peak ground reaction forces in the vertical and anteroposterior direction, suggesting increased subject confidence in their knee. Wearing the knee bandage also enabled the patients to reduce all measured parameters in the anteroposterior direction (rmsFx, intFx, rmsAx) during both the adjusting and balancing phases (P < 0.001 ). A significant reduction in the center of pressure path length further indicated an enhanced steadiness during the one-legged stance. CONCLUSIONS: It was concluded that a compression sleeve improved the total integration of the balance control system and muscle coordination.

Adult↗

PubMed1996

Knee joint muscle function after patellectomy: how important are the hamstrings?

Twenty-three patients who had undergone unilateral patellectomy were tested using the Cybex II isokinetic dynamometer 9 years postoperatively. The results were compared with the performance of the uninvolved joint. There was a good correlation between loss of the quadriceps muscle function and loss of the hamstrings muscle function at 60 deg/s (R = 0.7, P < 0.001). Patients who showed a loss of quadriceps function of less than 40% also maintained good hamstrings function. A good or excellent functional result could be expected in these patients. If the loss of quadriceps function was more than 40%, a proportional loss of flexion torque was seen, indicating a functional impairment of the knee joint muscles not solely attributable to the loss of the lever arm. Furthermore, all patients with a loss of peak flexion torque of more than 30% showed an unsatisfactory clinical result. The evaluation of the hamstrings muscles by measuring the peak flexion moment at 60 deg/s can therefore be used as a preoperative assessment and as a guideline for rehabilitation after patellectomy.

Activities of Daily Living↗

PubMed1996

[Desflurane and isoflurane. A comparison of recovery and circulatory parameters in surgical interventions].

OBJECTIVES: The new volatile anaesthetic desflurane is characterized by very low blood-gas and tissue-blood partition coefficients, so that rapid induction of anaesthesia and shorter recovery times can be expected. The aim of this investigation was to compare the effects of desflurane and isoflurane on haemodynamics and recovery time when used as part of a balanced anaesthesia technique for elective surgery. METHODS: Fifty patients (18 years and older, ASA status I-III) scheduled for elective surgery (no laparoscopies) of at least 60 min duration were included in this open, randomised, phase-III clinical trial. After oral premedication with midazolam 7.5 mg 45 min before transfer to theatre, anaesthesia was induced with fentanyl 0.1 mg and thiopental 5 mg/kg; succinylcholine or vecuronium facilitated intubation. Desflurane and isoflurane, respectively, were used for maintenance of anaesthesia, both in 50% N2O, with the inspired concentration adapted to the degree of stimulation. All patients were ventilated in a semi-closed system; muscle relaxation was achieved with vecuronium. The electrocardiogram, heart rate (HR), and direct arterial blood pressure (BP) were recorded continuously and anaesthetic gas detection was performed by an infrared absorption technique. With termination of surgery the volatile anaesthetic was discontinued and the following emergence times recorded: spontaneous ventilation (VT > 300 ml), extubation, eye opening, correctly answering the date of birth, arrival in and possible discharge from the post-anaesthesia care unit (PACU). RESULTS: In all, 49 patients were studied at random (desflurane n = 24, isoflurane n = 25). Data of demographics and anaesthetic technique were comparable in both groups (Tables 2 and 3). Anaesthetic elimination (expressed as FA/FAO) was significantly more rapid in the desflurane group 3 min after termination of anaesthesia (Fig. 1). Comparing the emergence times, there was no significant difference between desflurane and isoflurane: in both groups patients opened their eyes 12 min (median time) after termination of the operation (Table 4). Haemodynamics (HR, systolic and diastolic BP) were comparable at intubation, skin incision, end of surgery, extubation, and in the PACU (Fig. 2a, b). In 2 patients a rapid increase in the inspired concentration of desflurane during induction of anaesthesia produced a profound sympathoadrenergic reaction with an excessive increase in BP and HR. Similar reactions in other patients did not occur when the inspired concentration of desflurance was slowly increased. CONCLUSIONS: Despite the physicochemical properties of the new agent, emergence times were similar for desflurane and isoflurane in our study. These results, which are in contrast to those of some other authors, are most probably due to the study design, which included the use of premedicants (midazolam) and a low dose of fentanyl. The reported sympatho-adrenergic reactions after rapid changes in the inspired concentration of desflurane during induction of anaesthesia have been observed by others as well. It seems that this initial cardiovascular stimulation can be avoided by slow increases in desflurane concentration. In summary, desflurane compares to isoflurane in balanced anaesthesia for general surgical procedures with regard to haemodynamics, while the time to awakening is not necessarely reduced.

Adolescent↗

PubMed1996

Posterior stabilization in L5-S1 isthmic spondylolisthesis with paralaminar screw fixation: anatomical and clinical results.

Combined anterior and posterior fusion with posterior instrumentation may be indicated in the treatment of select cases of L5-S1 spondylolisthesis. The instrumentation, however, is expensive and usually bulky, occasionally requiring removal. In an effort to avoid these problems, an L5-S1 paralaminar screw technique was developed for posterior stabilization after an L5-S1 anterior interbody fusion. The technique involves the placement of cortical screws from the base of the articular process of S1 to the pedicle of L5. This study evaluates the anatomic applications and clinical results of this technique. The relationship between the screw and L5 nerve root was examined using five cadaveric specimens with olisthesis of 0, 25, 50, and 75%. This work demonstrates that the screws can only be inserted safely if an L5-S1 olisthesis of at least 25% is present. If < 25%, the screws will either impinge on or directly injure the L5 nerve root. In the clinical study, the outcomes of 20 patients who had an isthmic spondylolisthesis of 25-81% and were treated with partial reduction, L5-S1 anterior interbody fusion, and L5-S1 posterior paralaminar screw fixation were reviewed. Nineteen patients had adequate posterior stabilization to completely heal an L5-S1 anterior interbody fusion without loss of the correction. In one patient, a pseudarthrosis occurred secondary to poor surgical technique of both anterior and posterior fusions. This patient required an additional L4-S1 posterior fusion 9 months later and had a good clinical outcome. No other complications due to screw placement occurred. We conclude that this procedure can be used safely and reliably for the posterior stabilization of L5-S1 after stable anterior L5-S1 interbody fusion in residual slips of at least 25%. Prerequisites are proper patient compliance and low weight. Compared with other posterior instrumentation systems, this screw fixation is inexpensive and does not require implant removal. The disadvantages of the method are the degree of difficulty of the procedure and the limited clinical application to cases of L5-S1 spondylolisthesis with corrected residual slips of 25 to 50-60%. The procedure is technically demanding and should be limited to those surgeons who are comfortable with the method.

Adolescent↗

PubMed1995

[The anterior cruciate ligament, an important structure of the knee joint].

The anterior cruciate ligament (ACL) is a crucial structure for a normal kinematic of the knee joint. Its rupture has been thought to present the initiation of a sequel leading to secondary damage of the meniscus and finally to osteoarthritis. Diagnosis of an ACL rupture is based on the history as well as on the physical examination. A positive Lachman-sign is diagnostic for an ACL lesion. The question whether an ACL rupture should be operated or not must be decided individually and is based on the demands of the patient. Conservative treatment includes rigorous physical therapy emphasizing strengthening exercises of the hamstrings and the gastrocnemius muscles as well as prorioceptive training. The indication for reconstruction is given, should instability persist. The timing of the operation is important for the outcome. This paper presents an overview of the literature including the rehabilitation program and a diagnostic concept used by the authors.

Anterior Cruciate Ligament↗

PubMed1995

Kinematic and kinetic comparison of downhill and level walking.

Kinematic and kinetic data were collected from 12 healthy subjects whilst they performed both downhill and level walking at a controlled cadence. A ramp of 6 m length and a gradient of -19% was used for downhill walking and this incorporated the same force platform that was used for level walking. Planar net joint moments and mechanical power at the ankle, knee, and hip joints were calculated for the sagittal view using force platform and video records based on standard inverse dynamics procedures. On the basis of differences in ankle, knee, and hip joint kinematics the ankle joint was seen to compensate for the gradient at push off and during the swing, the knee joint from early stance through until early swing phase, and the hip joint from early swing through until the early stance phase. The major differences in joint moments and muscle mechanical power were seen in the knee and ankle joint. Whereas peak moments and muscle power were much higher for downhill walking in the knee joint, these measures were significantly smaller at the ankle joint. Hip joint moments and muscle power estimates were only slightly larger for downhill walking. These data explain well the problems that patients with patellofemoral pathology and anterior cruciate ligament (ACL) deficiency encounter with downhill walking, and the muscle soreness experienced by mountain trekkers. RELEVANCE: Biomechanical estimates of musculoskeletal loadings in gait are invariably derived from laboratory studies of walking over a level surface. In this study comparisons were made between downhill and level walking in order to appreciate more fully the increased loadings on the lower extremity under more stressful but not atypical conditions. The data so derived provide the necessary basis for the prediction of loadings on specific muscle/joint structures and can serve as a foundation for exercise prescription with patients recovering from injury or orthopaedic surgery.

Journal Article↗

PubMed1994

1994 Nicola Cerulli Young Researchers Award. Downhill walking: a stressful task for the anterior cruciate ligament? A biomechanical study with clinical implications.

Accelerated rehabilitation after anterior cruciate ligament (ACL) reconstruction has become increasingly popular. Methods employed include immediate extension of the knee and immediate full weight bearing despite the risks presented by a graft pull-out fixation strength of 200-500 N. The purpose of this study was to calculate the tibiofemoral shear forces and the dynamic stabilising factors at the knee joint for the reasonably demanding task of downhill walking, in order to determine whether or not this task presented a postoperative risk to the patient. Kinematic and kinetic data were collected on six male and six female healthy subjects during downhill walking on a ramp with a 19% gradient. Planar net joint moments and mechanical power at the knee joint were calculated for the sagittal view using a force platform and videographic records together with standard inverse dynamics procedures. A two-dimensional knee joint model was then utilised to calculate the tibiofemoral shear and compressive forces, based on the predictions of joint reaction force and net moment at the knee. Linear envelopes of the electromyographic (EMG) activity recorded from the rectus femoris, gastrocnemius and biceps femoris muscles were also obtained. The maximum tibiofemoral shear force occurred at 20% of stance phase and was, on average, 1.2 times body weight (BW) for male subjects and 1.7 times BW for female subjects. The tibiofemoral compressive force was 7 times BW for males and 8.5 times BW for females during downhill walking. The hamstring muscle showed almost continuous activity throughout the whole of the stance phase.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Influence of dentinal fluid and stress on marginal adaptation of resin composites.

The influence of dentinal fluid and of a number of stress procedures on the quality of the margins of class V restorations located in both enamel and dentin was quantitatively assessed in vitro with the aid of a scanning electron microscope. The materials tested were GLUMA 2000 experimental, Prisma Universal Bond 3, and Syntac, together with the fine hybrid composites supplied by the respective manufacturers (Pekafill, AP.H, and Tetric). All materials achieved over 95% of "continuous margin" in enamel before and after stressing. In dentin, the initial values, with as well as without dentinal fluid simulation, were situated between 93.2 and 98.2%. With GLUMA 2000 experimental after stressing, a "continuous margin" occurred in only 50.2%, but with Prisma Universal Bond 3 and Syntac, the value was 79.0%. The influence of dentinal fluid simulation was dependent on the dentinal adhesive used. The effects of the various stress procedures were not significantly different.

Body Fluids↗

PubMed1993

[Stress on the femoropatellar joint in downhill walking--a biomechanical study].

Kinematic and kinetic data were collected of 6 male and 6 female healthy subjects. For downhill walking a dismountable slope of 6 m length and a grade of 19.3% was built. Planar net joint moments and mechanical power at the knee joint were calculated for the sagittal view using force platform records based on standard inverse dynamics procedures. On the basis of a two dimensional knee model the patello femoral joint compressive forces were calculated. While the maximal extension moment for level walking was only 1.2 +/- 0.5 Nm/kg bw at a knee flexion angle of 20 degrees it was 2.6 +/- 0.6 Nm/kg bw at an angle of 40 degrees for downhill walking. This increased moment and knee flexion angle yields a 3 to 4 times bigger femoropatellar joint compressive force for downhill walking compared to level walking. Due to a smaller moment arm of female subjects the patello femoral joint compressive forces were bigger for females compared to males (14 N/kg bw for male subjects, 18 N/kg for female subjects during level walking and 50 N/kg bw for male subjects, 70 N/kg for female subjects during downhill walking). The femoropatellar joint compressive force for downhill walking is comparable to running, squatting or downstairs walking. Based on this investigation downhill walking must be considered a strenuous task for the femoro patellar joint and explains well why patients with anterior knee pain or osteoarthritis have problems during downhill walking.

Adult↗

PubMed1992

How can a standard software package for data management in anesthesia be achieved?

Collecting data for administrative, statistical, medical, and organizational purposes is becoming increasingly important in anesthesia. In 1986 the Swiss Society for Anesthesiology decided to create a program that would be compatible for different computers and would expedite data collection. The system developed was called Information System for Operations (ISOP), which was written in the database and programming system Massachusetts General Hospital Utility Multi Programming System (MUMPS). It was installed in eight hospitals and met the initial requirements, but the individual requirements of the hospitals were greatly underestimated. MUMPS has an impressive data storage capability and handling when used in a personal computer (PC) network. The user-interface, however, is inferior to other PC packages, partly because windowing and mouse support were not implemented when the ANSI standard was set. Improved statistical programs, a module for on-line data acquisition, and intensive care unit (ICU) use will be additional modules to the program.

Anesthesia Department, Hospital↗

PubMed1989

[Intraoperative, direct and continuous measurement of stomach pH following pretreatment with ranitidine or sodium citrate].

We carried out continuous direct pH measurements of gastric fluid in 49 female patients pretreated with 300 mg ranitidine by mouth on the evening prior to surgery and 150 mg by mouth before the operation. A further 51 women were pretreated with 30 ml sodium citrate shortly before admission to the operating room. Twenty patients received 30 ml sodium citrate via a separate gastric tube after the first pH measurement; 22 were given no premedication. In 95% of cases, 30 ml sodium citrate was found to increase the pH to over 3.5 within 5 min; a failure rate of 5% can therefore be expected. This can be explained mainly by the failure of sodium citrate to mix thoroughly with the gastric fluid. Pretreatment with ranitidine increased the pH to over 4.0 in every case, and the pH on extubation was still over 4.0 even after delayed pH on extubation was still over 4.0 even after delayed or prolonged operations. We recommend that 30 ml sodium citrate be given shortly before the beginning of emergency obstetric operations. However, we prefer ranitidine for elective operations in patients at risk for aspiration because it increases of the gastric fluid pH to at least 4.0 in every case.

Citrates↗

PubMed1988

[Sex- or symptom-specific behavior of male residents? An analysis of diagnosis and therapy of ambulatory female and male patients with abdominal pain].

We investigated the influence of the patient's gender for diagnostic and therapeutic approach of physicians at the outpatient clinic of the university hospital of Basle. In a prospective study 13 male residents in their second and third year of medical training were observed in their management of 25 female and 25 male patients presenting with the leading complaint of abdominal pain with regard to taking of the medical history, the physical examination and the performed diagnostic and therapeutic procedures, without informing the participating physicians. The time spent for the first consultation and the number of follow ups performed were registered. Following differences in the management of female and male patients were observed: The time spent at the first consultation was 59 +/- 5 minutes in female and 45 +/- 3.5 in male patients (p less than 0.03). Fundoscopic examination was three times more often performed in female patients. Endoscopic examinations were more often observed in male patients (p less than 0.01). Antacids and H2-antagonists were more frequently prescribed in male (p less than 0.01). Spasmolytics and laxatives more frequently in female (p less than 0.01). In summary in male patients the diagnosis of functional disease was predominantly made after exclusion of an organic disease what does explain the use of more diagnostic procedures and the induction of a more specific therapy.

Abdomen↗

PubMed1987

[Development of an information system for operations].

The report describes a computer system that provides statistical information on the anesthetic and surgical procedures performed by anesthetists and surgeons, reports on the operative activity of the anesthesia and surgical departments, and assists in daily scheduling of the program. Additional programs can be used for billing, displaying the use of (operating room OR) facilities by the various surgical divisions, and showing the actual stage of on-line operations with monitors. The software system MUMPS has been found to be a low-priced yet efficient and versatile multiuser system. The main features of the program are ease of use, prospective data entry (i.e. during the entire stay of the patient), and the possibility of modifying and expanding the system easily. Missing or inaccurate data are automatically brought to the attention of those who have performed the operation or the anesthesia by a program that is run periodically. The system has been found to be a useful tool for the daily scheduling of the OR program. It provides data for better scheduling of personnel and records can also be kept regarding the professional experience of physicians. The major deficiency of the program at this stage is its lack of a hierarchical structure. For example, it is unable to record multiple operations and/or anesthetic procedures for the same patient. This deficiency will be corrected in a newer version of the program.

Anesthesia↗