Biomedical subjects

F C Bakker

Publications and source records attributed to F C Bakker.

18 recordsLinked to original sources

PubMed1995

Surgical treatment of liver injury with an absorbable mesh: an experimental study.

Uncontrollable bleeding remains a life-threatening problem in severe liver injury. The application of an absorbable mesh has been reported in a small number of patients. To evaluate an absorbable mesh wrap in standardized conditions, we performed an experimental study in 14 female pigs. A standard liver laceration imitating a blunt injury grade IV (Liver Injury Scale of the American Association for the Surgery of Trauma) was made in all animals. Heparin was administered to mimic coagulopathy. After randomization, seven animals received a polyglycolic acid (Vicryl) mesh wrap to control bleeding. Seven animals served as controls. Six of seven animals with a mesh wrap survived. Six of seven animals in the control group died (p = 0.02, Fisher's exact test). Intrahepatic pressures in the treated group varied from 3 to 55 mm Hg. Liver function tests in surviving animals were temporarily elevated. Necropsy at 2 weeks demonstrated adhesions to the wrapped lobe, but no hematoma, free bile, or abscess. Histologic examination showed a foreign-body reaction to the mesh and necrotic parts in the liver. It is concluded that an absorbable mesh wrap can effectively control bleeding from severe liver injury and improve survival in an animal model, although it may cause some damage to liver tissue.

Animals↗

PubMed1994

Longitudinal development of young talented speed skaters: physiological and anthropometric aspects.

A longitudinal analysis of a group of speed skaters was done to identify the performance-determining factors for a successful speed skating career. This paper presents both the physiological and anthropometric results of this longitudinal study. Twenty-four athletes from the Dutch National Junior Speed Skating Team were followed from age 16-17 yr to age 20-21 yr. During the development from junior to senior speed skater, a number of anthropometric and physiological variables changed. There were no differences between successful and unsuccessful speed skaters from an anthropometric perspective; consequently, it was not possible to distinguish successful from unsuccessful athletes on anthropometric grounds. The longitudinal data showed that at a younger age the successful speed skaters had similar oxygen consumption, mechanical efficiency, and power output values compared with the unsuccessful speed skaters. Later in the study, successful speed skaters distinguished themselves by the ability to produce higher power output values. There were no anthropometric or physiological relationships found in this study on which performance at the age of 20-21 yr could be predicted with measurements at a junior age.

Adolescent↗

PubMed1992

Supramaximal cycle tests do not detect seasonal progression in performance in groups of elite speed skaters.

Seven female and eight male elite junior skaters performed cycle ergometer tests at four different times during the 1987/1988 season. The tests consisted of a Wingate-type 30-s sprint test and a 2.5-min supramaximal test. The subjects were tested in February, May and September 1987 and in January 1988. Maximal oxygen consumption was measured during the 2.5-min test. With the exception of the maximal oxygen consumption of the women in May which was about 6% lower than in the other three tests, no seasonal changes in the test results could be observed--this, in spite of a distinct increase in training volume (from 10 to more than 20 h.week-1) and training intensity in the course of the season. When the test data were compared to those of elite senior skaters, it appeared that the junior skaters showed the same values for mean power output during the sprint test [14.2 (SD 0.4) W.kg-1 for the men and 12.6 (SD 0.5) W.kg-1 for the women] and maximal oxygen consumption [63.1 (SD 2.8) ml.kg-1.min-1 for the men and 55.3 (SD 3.5) ml.kg-1.min-1 for the women, respectively] as found for senior skaters. It seemed, therefore, that the effects of training in these skaters had already levelled off in the period before they participated in this investigation. In contrast to previous studies, no relationship could be shown between the test results and skating performance. This was most likely due to the homogenous character of the groups (mean standard deviations in power and oxygen consumption were only 5%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

Criteria for reliable selection of the lowest level of amputation in peripheral vascular disease.

To improve the chances for the amputee to become ambulatory the most distal level of amputation should be selected in patients with end-stage peripheral vascular disease. Physical examination alone provides insufficient information when amputation levels are closely related to areas with signs and symptoms of ischemia. In the present series of 85 lower extremity amputations the predictive values of clinical parameters and skin perfusion pressure measurements are assessed. The role of clinical judgment is clarified: the most distal level of amputation is to be selected by physical examination, but further information is required to assess the healing potential at the selected level. The presence of palpable pulses immediately above the selected level correlates well with primary wound healing (p less than 0.001, negative predictive value 100%). The absence of palpable pulses and angiographic patency scores are of no clinical value in amputation level selection. Skin perfusion pressure measurements were of excellent predictive value (p less than 0.001, positive predictive value 89%, negative predictive value 99%). According to these data a strategy is proposed for routine determination of the lowest level of amputation, where primary wound healing can be expected.

Adult↗

PubMed1991

Antibiotic concentrations in the groin wound after vascular prosthetic implantation.

The kinetics of systemically and locally administered cefuroxime or ceftazidime in wound fluid were investigated in the period after vascular prosthetic implantation. Cefuroxime or ceftazidime was administered intravenously in patients. Simultaneously 250 mg ceftazidime or cefuroxime was added to preclotted blood. Locally administered antibiotics could not be detected in our samples. In groin fluid samples 24-48 h after the operation the average concentration of cefuroxime was 8.3 and of ceftazidime 5.0 mg/l. The decline of the concentration of cefuroxime or ceftazidime in groin fluid seems to be much slower than one would expect from the half-lives of the antibiotics. We conclude that cefuroxime and to a lesser extent ceftazidime are suitable as prophylactic agents in arterial reconstruction.

Aged↗

PubMed1991

Individual differences in reactivity to and coping with the stress of lecturing.

The aim of this study was to evaluate the moderating effect of several psychologically and biologically defined characteristics for both psychological and physiological indices of reactivity to and coping with lecturing stress. Student teachers were measured in two standardized lecturing situations: once at the start of a three-month practice period and once at the end of this period. Reactivity was operationalized as an increase in heart rate, cortisol excretion and subjective anxiety responses in anticipation of and at the start of the lecture. Coping was operationalized as the attunement of these responses during, or recovery after lecturing (short term coping), and as the adaptation of these responses across the three-month practice period (long term coping). It was found that reactivity to and (particularly long term) coping with the lecturing stressor could well be predicted by moderators such as physical fitness, extraversion, neuroticism, social anxiety and several coping styles. Specificity of predictor sets for sex and response parameters is discussed.

Adaptation, Psychological↗

PubMed1991

Stress and coping in lecturing, and the stability of responses across practice.

The central issues of the present paper are the responses to the stress of lecturing in a standardized situation, and the adaptation to this stressor across a period of real-life lecturing practice. Special attention is given to the stability of rank-order in the physiological and psychological responses to the lecturing stressor across practice. Lecturing in the standardized situation involved lecturing at the training institute to six fellow student teachers and two members of the university staff. The responses to be measured were heart rate, cortisol excretion and subjective anxiety. The results indicate that lecturing is stressful for student teachers. The adaptation in stress responses was very significant. Despite the significant reduction in the stress responses, a considerable stability of rank-order was found, indicating that subjects who were the most reactive before practice were still more reactive after practice. The implications of a high stability in reactivity are discussed.

Adaptation, Psychological↗

PubMed1990

A multivariate analysis of determinants of wound healing in patients after amputation for peripheral vascular disease.

In a prospective study 53 patients undergoing amputations of the lower limb were evaluated for clinical criteria, laboratory results, pulse volume recordings, Doppler pressures, Photoplethysmographic Skin Perfusion Pressures (PPG/SPP) and angiography. The purpose of the study was to analyse which of these techniques predicts wound healing adequately after amputation. Forty-five patients eventually completed all tests. With the exception of PPG/SPP none of these tests were able to predict skin healing. The technique of PPG/SPP proved very reliable in helping to select the level of amputation, if measured anteriorly (P = 0.0001, r = 0.83). Angiographic scoring also correlated significantly (P = 0.0016) with a successful result. This study suggests that surgeons should not rely on their clinical acumen for the selection of the amputation level. In the absence of a reliable non-invasive test, angiography may well be useful but PPG/SPP will enable the surgeon to amputate on an optimal level and thus reduce complications and improve rehabilitation.

Aged↗

PubMed1989

The correlation of peroperative outflow resistance measurements with patency 109 infrainguinal arterial reconstructions.

The predictive value of outflow resistance measurements for the patency of femoro-popliteal and femoro-crural bypass grafts was analysed. Peroperative outflow resistance measurements were performed in 109 infrainguinal arterial reconstructions. Outflow resistance was significantly higher in occluded bypasses compared with those which remained open (P less than 0.01), but there was a considerable overlap of values in both groups. Statistical analysis of the correlation between outflow resistance and patency rates at 3 months revealed a marginal correlation in the femoro-popliteal bypass group (R = -0.25), which was not significant (P = 0.064). In the femorocrural bypass group there was again only a marginal correlation (R = -0.27) but this was statistically significant (P = 0.05). These data demonstrate that intraoperative outflow resistance measurements are only of limited value for predicting bypass patency in individual cases.

Adult↗

PubMed1989

The anxiety thermometer: a validation study.

The aim of our study was to provide validation and reproducible data for the anxiety thermometer. This thermometer is either a continuous or a 10-point Likert-type scale on which subjects are asked to rate their anxiety feelings at a particular moment. It is a quick way to measure state-anxiety. As a validation criterion the State-Trait Anxiety Inventory (STAI) A-State scale was used. To test the reproducibility of the thermometer, a test-retest correlation coefficient was calculated, with a retrospective second thermometer score. The ego-threatening situation used was a written examination. Two experiments were carried out during different examination conditions. The data consistently indicated that the validity and reproducibility of the anxiety thermometer is fair (correlation coefficients between .60 and .78) In the second study, the possible influence of two factors on the retrospective scores were additionally tested.

Adult↗

PubMed1989

Failure of quantitative venous photoplethysmography to assess venous insufficiency: a prospective clinical study.

The increase of deep venous reconstructive surgery necessitates reliable tests for evaluation of the results, which requires quantization of the expelled volume. This could only be done with invasive measurements, but now it seems possible to calibrate photoelectric cells, and quantize the results. Nineteen limbs of patients with deep venous disease and seven limbs of healthy volunteers were evaluated, with methods known from the literature. In addition to measurements in standing position, these methods were used in the more patient-friendly sitting position. Invasively and noninvasively measured recovery times correlated well in the standing (R = 0.83) and in the sitting position (R = 0.86). However, the quantization of expelled volume did not significantly correlate. Also, the differences between expelled volume of controls and patients were only significant with invasive measurements in the standing position (P = 0.006) as well as in the sitting position (P = 0.004). The differences were not significant with the noninvasive method. In our opinion, photoelectric cells still do not offer an alternative for invasive measurements in the evaluation of results after venous reconstructive surgery.

Adult↗

PubMed1989

Morbidity in a microsurgical rat training model.

In a prospective study with 24 growing Wistar rats, with a mean body weight of 300 gram, microsurgery was trained. Patency as well as morbidity of the animals was assessed. There were 110 vascular anastomoses, constructed with various techniques. Of these, 104 were rendered for evaluation. The caliber of the vessels varied from 0.4 to 2.0 mm. On an average, the rats were operated two times, during which operations at least four anastomoses were created. Patency was related to caliber and flow rate of the vessel and varied between 50 and 100%. Mortality and weight increase, used to reflect morbidity were evaluated. Six animals died during or shortly after operation, three of them because of anaesthesia alone. Mean postoperative daily weight increase was 1 gram approximately. In the control group the weight increase was tripled. The rats needed two weeks after operation rats to regain their original weight. Analysis of results demonstrated highly significant difference between operated and non-operated rats. The study suggests, that morbidity of rats submitted to microsurgery will be reduced, if two weeks of recovery before other experiments are awaited. This may provide a standard for future experiments.

Anastomosis, Surgical↗

PubMed1989

Intermittent claudication and limb-threatening ischemia in systemic lupus erythematosus and in SLE-like disease: a report of two cases and review of the literature.

Intermittent claudication and limb-threatening ischemia caused by occlusion of large and medium-sized arteries are rare manifestations of systemic lupus erythematosus. So far only eight documented cases have been reported, predominantly in young women. In this report two more patients are described. There is no common opinion concerning pathophysiologic mechanism, but immunologic endothelial damage and circulating antibodies to phospholipid probably play a role. The results of medical and surgical treatment are disappointing, and amputation becomes necessary in more than half of the patients.

Adult↗

PubMed1988

Photoplethysmographic selection of amputation level in peripheral vascular disease.

In a prospective study 37 patients who required amputations of the leg were studied with a new technique: segmental photoplethysmographic skin perfusion pressures. The decision to amputate was made by a vascular surgeon in a traditional manner, with the aid of clinical criteria. The simple method of determining skin perfusion pressures with photoplethysmography is described; 273 measurements were performed. The technique proved to be highly correlated (r = 0.88) with wound healing after amputation, at a separating value of 21 mm Hg (p = 0.0001). The study suggests that the value of this noninvasive method will be to enable the surgeon to amputate at a lower level and to diminish complications and failure of rehabilitation.

Aged↗

PubMed1988

A technique to prevent aneurysm formation in microvascular anastomoses.

The occurrence of true aneurysm formation in microarterial anastomoses is well known. In up to 50% of microanastomoses this complication is found. In a microsurgical training group a new technique was taught, which did not give cause to any aneurysm formation at all. This technique allows only suturing with relative thin and many stitches, suturing of small edges of the vessel wall and short stripping of adventitia. Though operative skill perhaps is more demanding in this new technique, the merits are clear.

Anastomosis, Surgical↗

PubMed1988

Spontaneous subclavian vein thrombosis: a successful combined approach of local thrombolytic therapy followed by first-rib resection.

In 17% to 74% of patients with subclavian vein thrombosis, conservative treatment or venous thrombectomy led to residual symptoms. To improve these results, a prospective study was started in patients with subclavian vein thrombosis who were treated with a combined approach of local thrombolytic therapy followed by a first-rib resection. From 1983 to 1987 five patients entered the protocol. Total lysis was achieved in all cases. In the follow-up period, phlebography and strain-gauge plethysmography according to Whitney showed no recurrent thrombosis. All patients were able to resume their normal activities.

Adult↗

PubMed1987

Stress in student teachers during real and simulated standardized lectures.

This study describes and compares the intensity of stress responses, both psychologically and physiologically, to a real and a simulated stressor. The real stressor involved lecturing to a class of students in a post-secondary institution during a practice teaching course. The simulated stressor was a simulated, standardized lecture given in a lecture room to 6 fellow students and 2 members of the university staff. To gain insight into the intensity of the stress responses, the measurements took place before, during, and after lecturing. The adaptation to the stressor after a teaching practice period in which the student teacher gave at least 20 lectures was also studied. Subjective anxiety scores were obtained in both situations from 26 subjects. For 12 of these subjects, heart rate responses were also obtained. The psychological and physiological data indicated that lecturing imposes a severe load on the student teacher, especially at the beginning of the teaching experience. At the end of the practice course, all stress indices showed lower values. Heart rate and subjective anxiety scores indicated that the standardized lecture is experienced as more ego threatening than the real lecture.

Adaptation, Psychological↗

PubMed1982

The Hartmann procedure.

During a 10-year period, 59 patients had a Hartmann operation for diverticular disease (n = 19), carcinoma (n = 21), anastomotic disruption (n = 5), injury (n = 3) and various other conditions (n = 11). Twenty-two patients (37.3 per cent) died postoperatively. Wound infection or wound dehiscence occurred in 26 patients. Other complications inherent in this operation were colostomy necrosis or retraction (n = 12) and leakage of the rectal stump (n = 3). The mean hospital stay of the surviving patients was 28.4 days. Colorectal continuity was subsequently restored in 12 patients (32.4 per cent) and no difficulties were encountered with this procedure.

Adult↗