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Biomedical subjects

B Fink

Publications and source records attributed to B Fink.

At least 55 records · Page 3Linked to original sources
PubMed1997

Early detection of avascular necrosis of the femoral head following renal transplantation.

This prospective study included 43 patients undergoing renal transplantations. Magnetic resonance imaging (MRI) and X-rays of the hip joints were produced 3 and 12 months after transplantation. In 6 hip joints of 4 patients (9.3%), we discovered femoral head necroses just 3 months after transplantation. Three of the hip joints affected were symptomatic and 3 painless. The MR images taken 12 months after transplantation revealed no additional femoral head necrosis. A core decompression was performed on 3 joints. In contrast to those with core decompression, the femoral heads without core decompression showed a progression of the necrosis in 2 of 3 cases. All 4 patients with femoral head necroses were younger than 50 years and exhibited a premature conversion of the haematopoietic marrow to fatty marrow in the area of the proximal femoral metaphysis. A similar premature conversion to fatty marrow was seen in 6 of the 22 (27.2%) patients younger than 50 years and without femoral head necroses. The doses in long-term steroid medication and the steroid doses during the rejection periods of the patients with femoral head necroses were not significantly higher than those for the patients with premature conversion to fatty marrow. The latter had also not received significantly higher doses than the patients whose MRI findings were inconspicuous.

Adult↗
PubMed1997

Recurrent dislocation of the patella and the Goldthwait operation.

In this study 17 patients with recurrent dislocation of the patella were followed up 10 years after their Goldthwait operation. The subjective and clinical findings were excellent or good in 70%. X-radiographs indicated osteoarthritis of the femoropatellar joint in 60%. Concerning the aetiopathological factors, we found an increased external torsion of the afflicted extremity (measured by computed tomography).

Adolescent↗
PubMed1997

Avascular osteonecrosis of the acetabulum.

OBJECTIVE: To investigate the possible occurrence of osteonecrosis in the acetabulum in patients with non-traumatic necrosis of the femoral head. DESIGN AND PATIENTS: One hundred and seventy-nine patients with non-traumatic femoral head necrosis were assessed by MRI and radiography for the presence of acetabular necrosis. Three criteria were established to differentiate between osteonecrosis and osteoarthritic changes: (1) heterogeneous morphology and irregular contours of the lesion; (2) typical demarcation lines of osteonecrosis; (3) deficient accumulation of intravenous gadolinium in the affected regions. RESULTS: In four patients histological confirmation of acetabular necrosis was obtained. The MR analysis of 22 acetabula (9.5% of those examined) showed changes which suggested osteonecrosis. No cystic lesions were demonstrated in the subchondral bone of any patient. Two cases of acetabular necrosis were found without an ipsilateral femoral head necrosis. In two patients of the 14 who had undergone total hip replacement following necrosis of the femoral head, aseptic loosening of the acetabular component was found. CONCLUSION: The study suggests that acetabular necrosis may be an accompaniment to aseptic necrosis of the femoral head. Further work is required to assess its importance in premature loosening of the acetabular element of total hip arthroplasty.

Acetabulum↗
PubMed1997

Unexpected, tolerance-devoid vasomotor and platelet actions of pentaerythrityl tetranitrate.

Efficacy of nitrate therapy is limited by tolerance. A surprising upregulation of ex vivo platelet activity, a decrease in platelet thiol levels, and an enhanced release of vasoconstrictors from platelets is associated with enhanced superoxide-mediated oxidant stress leading to vascular tolerance to nitrates. We tested the NO-donor pentaerythrityl tetranitrate (PETN), which to date had not been precisely tested either with regard to the induction of tolerance or to a potential development of changes in platelet activity in comparison with glycerol trinitrate (GTN). Long-term instrumented dogs nonintermittently received: 1.5 microg/kg/min GTN, i.v., with or without vitamin C (55 microg/kg/min, i.v.) or PETN 4 x 60 mg/day orally for 5 days. Tested daily were (a) the dilation of the epicardial arteries, (b) thrombin-induced (0.5 U/ml) increases of the intracellular Ca2+ concentration and aggregability of platelets, (c) concentrations of reduced low-molecular-weight thiols (LMTs) in plasma and platelets, and (d) formation of reactive oxygen species (ROSs). During nonintermittent PETN and during GTN with additional vitamin C, a 9.8 +/- 0.4% coronary artery dilation was observed in contrast to that with GTN alone, which resulted in complete tolerance at day 4. This vascular tolerance was associated with enhanced platelet activity and formation of ROSs (incubated platelets) and a 38 +/- 3% reduction in LMT. These unfavorable changes were absent in the presence of PETN or with additional vitamin C as an antioxidant. Vascular tolerance associated with platelet upregulation is avoided either by nonintermittent nitroglycerin (5 days) when vitamin C is coadministered or by pentaerythrityl tetranitrate without the coadministration of vitamin C.

Animals↗
PubMed1996

Tolerance to nitrates and simultaneous upregulation of platelet activity prevented by enhancing antioxidant state.

We analysed the induction of tolerance to nitrates both in the vasculature (in vivo) and platelets (ex vivo). Simultaneously, we tested mechanisms underlying the induction of tolerance and interventions to prevent or overcome this phenomenon. For this purpose nitroglycerin (GTN 1.5 micrograms/kg per min i.v.), alone or in combination with ascorbate (55 micrograms/kg per min i.v.) as antioxidant, was infused continuously for a period of 5 days into chronically instrumented dogs. Along with haemodynamic parameters, ex vivo platelet function was continuously monitored. Following the start of GTN infusions there was a maximal coronary dilator response (245 +/- 15 microm) and, as an index of venodilation, a fall of left ventricular end-diastolic pressure (by 2.3 +/- 0.4 mmHg). Both responses declined progressively and disappeared during the infusion period. However, in combination with ascorbate as antioxidant the dilator responses were maintained fully throughout the infusion period. With GTN alone there was a progressive, unexpected upregulation of platelet activity demonstrated by enhanced thrombin-stimulated intracellular Ca2+ levels and increases in the microviscosity of platelet membranes (indicating enhanced receptor expression) associated with a progressive impairment in basal, unstimulated cGMP levels. These changes could also be prevented completely by i.v. co-administration of ascorbate. From these results it is concluded that vascular tolerance is closely reflected by simultaneous changes in platelet function and further, that both can be prevented completely by appropriate antioxidants such as ascorbate.

Animals↗
PubMed1996

Holmium: YAG laser-induced aseptic bone necroses of the femoral condyle.

In laser-controlled cartilage-ablation arthroplasties, the attention focuses more and more on the depth effects of the various lasers, especially as heat necroses of the cartilage and even in places of the bone were found in animal experiments. For the first time, two cases of holmium: YAG laser-induced aseptic bone necrosis of the femoral condyles after cartilage ablation are described.

Cartilage, Articular↗
PubMed1996

Osteoneogenesis and its influencing factors during treatment with the Ilizarov method.

The radiographs of 57 patients who had undergone 58 callus distractions and 13 epiphyseal distractions were evaluated. During the course of treatment, the density of the distraction areas on radiographs was measured in total and along the medial, lateral, ventral, and dorsal margins using a digital radiograph processing system. The densities of the whole distraction length were correlated to the following parameters: age of patient, start of distraction after corticotomy, mean distraction speed, mean amount of weight load during the period of distraction and consolidation, location of corticotomy (distal femoral metaphysis versus the proximal tibial one), and diclofenac medication. Except for the location of corticotomy and the diclofenac medication, the density was influenced by all these parameters. Age of the patient and weight load were the most important parameters. Patients with leg shortening caused by poliomyelitis and a patient with a shortened leg after amniotic strangulation showed a slower rise of the density trend curve on radiographs than the other patients. When comparing the different regional density curves, a significant gradual density decrease could be observed from the medial to the lateral side in the femur, from lateral to medial in the tibia, and from the dorsal to the ventral side in both bones. The respective differences between lateral and medial density, and between dorsal and ventral density, were significantly higher in cases of callus distraction than in cases in which epiphyseal distraction had been used. The amount of bone regeneration varied regionally primarily because of the inhomogeneous soft tissue covering of the bone and the impairment of its local blood supply by the surgical exposure for the corticotomy. The clinical relevancy of the various parameters for osteoneogenesis is discussed in this article.

Adolescent↗
PubMed1996

Influence of joint stability on the results of arthroscopic subacromial decompression.

We performed arthroscopic subacromial decompression on 70 patients. Each of them had either type I or type II impingement according to Neer. Sixty-five patients were then observed for a postoperative period of three years. The follow-up checks were performed by ultrasound in order to assess the extent of passive inferior shift of the humeral head, compared with the preoperative stage. A shoulder score of 100 was used as a reference. Whereas the average preoperative score was 58.5 (standard deviation +/- 12.2), postoperative results showed an increased average value of 79.7 (standard deviation +/- 11.4). In twenty cases (31% of all treated patients), the postoperative score was less than 85 points, i.e. treatment had shown no results. Comparing these patients with the other 45 who had a score above 85 points, we noted that the age of patients, the preoperative duration of complaints, the preoperative score and duration of the postoperative stay in hospital were of no relevance to the results. However, among all patients, ultrasound measurements showed significant deviations in the extent of passive inferior shift of the humeral head. Patients in the group with unsuccessful treatment had an average shift value of 5.1 mm. (+/- 2.0 mm), compared with an average value of only 2.4 mm (+/- 0.9 mm) among patients in the successful group. The statistical negative Pearson correlation coefficient of -5.36 between postoperative score and inferior shift of the humeral head is very significant. We conclude that hypermobile glenohumeral joints or unstable joints should not be treated by subacromial decompression in the presence of any subacromial pathology.

Adolescent↗
PubMed1995

Reactivation of a tuberculous coxitis due to loosening of a total hip endoprosthesis.

A 45-year-old woman who suffered from juvenile tuberculous coxitis at the age of 4 is presented. Her hip joint replacement lasted for 18 years and then needed replacing. Intraoperatively removed caseous soft tissue and an opalescent secretion histologically resembled a tuberculous focus, and bacteriological culture grew a Mycobacterium tuberculosis strain. Four months after the replacement, the patient suffered from a tuberculosis-induced septic loosening of the newly replaced hip joint endoprosthesis. The tuberculosis relapse was probably due to aseptic loosening of the first hip joint endoprosthesis.

Female↗
PubMed1995

Resection arthroplasty of the metacarpophalangeal joints in rheumatoid arthritis. Results after more than 15 years.

In a retrospective study of resection arthroplasty of the MP joints in rheumatoid arthritis, 23 patients (32 hands, 128 joints) have been followed for 15 to 22 years. Patient satisfaction was high, and all patients had significant pain relief. Active motion of the joints averaged 35 degrees, ranging from full extension to 35 degrees of flexion. Ankyloses developed in five hands (13 joints, 10%). Ulnar deviation of more than 15 degrees occurred in six patients (ten hands, 30%). Over the course of several years a significant remodelling of the joints was to be observed. In six hands (19%) the metacarpal heads became spontaneously restored to ball-shaped geometry. Gross metacarpal resorption was observed in nine hands (30%), causing significant shortening of the metacarpals. In one-third of patients the final result was rated as good, fair and poor, respectively. Careful patient selection is mandatory. Patients with mutilating arthritis should be excluded from the procedure; rheumatoid destruction of the wrist joint definitely influences the final result.

Arthritis, Rheumatoid↗
PubMed1995

[Factors affecting bone regeneration in Ilizarov callus distraction].

We evaluated the X-rays of 36 patients who underwent 50 callus distractions. With the aid of a computerized digitalisation system for analogue films, the relative X-ray density of the distraction area was calculated for each X-ray. These relative X-ray densities were figured graphically for the duration of treatment for each patient. In the consolidation phase, the graph of each patient had a logarithmic relationship. The gradients of the logarithmic density curves were considered an indicator of the quantity of new bone formation. These gradients were correlated to the following clinical parameters: age of the patient, beginning of distraction after corticotomy, average speed of distraction, average weight bearing during the distraction and consolidation phase, location of corticotomy (distal femur versus proximal tibia) and diclofenac medication. Except for the location of the corticotomy and diclofenac, all parameters had an influence on osteoneogenesis by callus distraction. The parameters affecting new bone formation the most were the age of the patient and weight bearing. Patients aged under 18 years (p = 0.005), beginning of distraction later than 8 days (p = 0.109), an average distraction speed below 1 mm/day (p = 0.079), and average weight bearing of more than 30 kg (p = 0.068 for the distraction phase and p = 0.089 for the consolidation phase) showed a quantitatively higher rate of new bone formation by callus distraction than the patients in the other groups. Patients with a shorter leg due to poliomyelitis and one patient with an amniotic leg tie showed a slower increase in X-ray density graphs than the other patients.

Absorptiometry, Photon↗
PubMed1995

Effect of ITF 296 on total effective vascular compliance in the anesthetized dog under autonomic blockade.

The effects of ITF 296 on venous tone, estimated as changes in total effective vascular compliance (TEVC), were investigated in the anesthetized, spontaneously breathing dog under autonomic blockade. TEVC was calculated from the correlation between the observed changes in central venous pressure (CVP) and the experimentally induced changes in blood volume during an 11-min cycle of whole blood infusion (2 ml/kg/min), withdrawal, and reinfusion. Stepwise increasing doses (short steady-state infusions) of ITF 296 (3, 10, and 30 micrograms/kg/min) resulted in a dose-dependent increase in TEVC (+27, +54, and +67%), whereas mean blood pressure (MBP) was reduced (-12, -23, and -33%, respectively). SIN-1 (10 micrograms/kg/min), administered at the end of the experiment as the reference NO-releasing compound, induced a rather complete venodilation (TEVC +182%) and a marked reduction in MBP (-47%). When nitroglycerin (NTG) was used as the reference compound at 1.5 micrograms/kg/min, a 67% increase in TEVC was observed. These results suggest that ITF 296 exerts a venodilator action but that this effect, and therefore the reduction in venous return, is less than that in response to nitrovasodilators such as SIN-1 or NTG. Furthermore, the vasodilator spectrum of ITF 296 compared to other nitrovasodilators is shifted somewhat more toward the arteriolar bed, with less pronounced venodilator effects, as indicated by the fall in MBP.

Anesthesia↗
PubMed1995

Effects of ITF 296 on epicardial coronary artery diameter during acute and long-term treatment in the conscious dog.

The action of the newly developed organic nitrate ITF 296 on large coronary arteries was investigated during acute and long-term treatment in the conscious dog, chronically instrumented for recording of large coronary artery diameter (CD), mean arterial blood pressure (MBP), and heart rate (HR). Short-term steady-state infusion of ITF 296 at doses of 0.1-30 micrograms/kg/min induced a dose-dependent increase in CD. Maximal coronary artery dilation (+11%) was reached at 10 micrograms/kg/min and no further increase was observed at 30 micrograms/kg/min. At the same doses no significant variations of MBP or HR were observed. Long-term administration (5-day infusion) of ITF 296 at 20 micrograms/kg/min resulted in a 10% increase in CD, and the effect was well maintained over the entire infusion period. MBP did not change significantly, whereas HR rose by 21% by the second day of infusion and remained elevated until the end of the treatment. These results confirm that ITF 296 is an effective dilator of large coronary arteries at doses devoid of peripheral hemodynamic effects. Moreover, the vasodilating effect on coronary arteries is well maintained during long-term administration, suggesting a reduced tolerance development.

Animals↗
PubMed1994

Reduced nitric oxide formation causes coronary vasoconstriction and impaired dilator responses to endogenous agonists and hypoxia in dogs.

We investigated the relative contribution of basal and agonist stimulated EDRF/NO release to the adjustment of coronary tone and myocardial perfusion in conscious dogs by inhibiting coronary endothelial NO formation with NG-nitro-L-arginine methyl ester (L-NAME). Chronically instrumented conscious dogs (n = 9) were prepared for measurement of mean arterial blood pressure (MAP), heart rate (HR), coronary blood flow (CF) and diameter of the left circumflex (CDLC) and left anterior descending (CDLAD) coronary artery, respectively. Intracoronary infusions of L-NAME (30.3 mM; 0.25 ml x min-1) caused significant increases in MAP and decreases in HR. CDLC decreased by 3.8% from 3.01 +/- 0.04 to 2.90 +/- 0.04 mm and CF decreases by 30% from 12.9 +/- 0.2 to 9.1 +/- 0.2 (aU). Peak reactive hyperemia (CFmax) evoked by 20-s-lasting occlusions of the left circumflex coronary artery decreased from 29.9 +/- 0.8 to 25.8 +/- 1.0 aU and maximal flow-dependent coronary dilation were reduced from 2.04 +/- 0.08 to 0.91 +/- 0.12% after inhibition of NO-synthesis. Intracoronary infusions of acetylcholine (ACh), adenosine (Ado), bradykinin (Bk), and papaverine (Pap) caused dose-dependent increases in CDLC and CF. Infusion of L-NAME nearly abolished the dilator effect of Ado on CDLC and reduced those to ACh, Bk and Pap. Increases in CF to ACh, Ado and Bk but not to Pap were reduced by L-NAME. Subsequent intracoronary infusions of L-arginine (303 mM; 0.25 ml x min-1) reduced L-NAME-induced CF-changes partly, but did not reverse coronary constriction. These results suggest that inhibition of the continuous release of nitric oxide markedly reduces myocardial perfusion in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Image analysis and synthesis of multimodal images in medicine.

Radiologic and clinical practice can be enhanced by improved access to multimodal image information. Analysis, visualization, method characteristic image processing and image synthesis is needed not only for the interpretation of the images but also for performing effective consultations with clinical colleagues and computer supported therapy planning and control strategies. A method is presented which enables the fast display, three-dimensional visualization and the modality oriented analysis of multimodal image information. Based on a unique image format, modality specific procedures and two- or three-dimensional processing tools of image analysis produce the input data for therapy planning programs. The easy use of this multimedia visualization tool enables radiologists and clinicians to deal with their image data. The description of methods and procedures, as well as typical examples of radiologic practice will demonstrate the efficiency of the presented system.

Algorithms↗
PubMed1994

Long term increases in coronary arterial conductance during five day infusion of low dose nicorandil.

OBJECTIVE: The aim was to test the effects of nicorandil on coronary arterial conductance and on a possible development of tolerance or cross tolerance with glyceryl trinitrate during a 5 d continuous intravenous infusion of this hybrid molecule (consisting of a combination of potassium channel activation and simultaneous nitro-ester induced soluble guanylyl-cyclase activation). METHODS: Continuous intravenous infusions of nicorandil at 2.5 micrograms.kg-1.min-1 and 10 micrograms.kg-1.min-1 into conscious chronically instrumented dogs were carried out for 5 d using a special portable infusion system. Employing additional short term infusions, dose-response curves were obtained by giving nicorandil or glyceryl trinitrate at increasing dosages both in the preinfusion control state and 4 h after terminating the nicorandil infusion. RESULTS: The 5 d infusion of 2.5 or 10.0 micrograms.kg-1.min-1 nicorandil resulted in a significant increase in large coronary artery diameter by 4.21 (SEM 0.14)% or 9.20(0.28)%, respectively. At the lower dose no significant tolerance or cross tolerance with glyceryl trinitrate was observed. However, at the higher dose there was a shift of the dose-response curve of both nicorandil and glyceryl trinitrate to the right, indicating some tolerance. The smaller dose did not induce hypotension or reflex increase in heart rate, whereas the larger resulted in a 42(2.5)% increase in heart rate. CONCLUSIONS: A dose regimen of 2.5 micrograms.kg-1.min-1 continuously administered for 5 d is capable of inducing a significant increase in coronary arterial conductance which was well maintained over the whole infusion period. Thus nicorandil can exert a selective large coronary artery dilatation and may bring about a well maintained increase in epicardial coronary conductance, especially when applied as a low dose slow release preparation which circumvents hypotension and increase in heart rate.

Animals↗