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Biomedical subjects

F Kummer

Publications and source records attributed to F Kummer.

At least 19 recordsLinked to original sources
PubMed2001

Effect of the angle of the screw on the stability of the mandibular sagittal split ramus osteotomy: a study in sheep mandibles.

We compared the biomechanical stability of 60 degrees and 90 degrees angles for insertion of screws for fixation of sagittal split ramus osteotomies (SSROs) in 10 sheep mandibles in vitro. After 5 mm advancements, the osteotomies were fixed with screws 2 mm in diameter inserted with a torque control screwdriver at either 60 degrees or 90 degrees to the long axis of bone, in a matched pair experimental design. All specimens were then loaded in a physiological manner and the load-displacement of the osteotomies was recorded. Data for resistance to movement were compared by a paired t -test. The mean (SD) resistance to movement for the 60 degrees and 90 degrees screw insertions was 63.4 (27.7) N/mm and 59 (22.3) N/mm respectively. There was no significant difference between the groups. This correlates with clinical findings.

Animals↗
PubMed1999

[Clinical aspects and diagnosis of pulmonary thromboembolism].

The symptomatology of PTE is good for the suspicion of PTE only. Symptoms are mainly based on dyspnoea (respiratory rate) and pain in the chest. Clinical diagnostic procedures, on the other hand, are backed up by evaluation of specific risk factors (previous thrombosis, post-operative state, immobilisation) and search for deep venous thrombosis (DVT). Blood gas analysis is very sensitive to unravel (latent) respiratory failure, along with established routine measures (blood pressure, ECG, chest-film) and additional echocardiography. Most important in our experience is a perfusion scan at the earliest opportunity. Spiral-CT angiography is indicated in special cases only. We looked at 115 consecutive patients with suspected PTE and found close correlations between risk profiles of thrombosis, pathological BGA and high probability perfusion scans. DVT was detected in 50% only. Positive predictive values for high risk and pathological BGA were 86 and 92%, respectively. An algorithm for diagnostical/therapeutical strategies is presented. The early application of an heparin-bolus is stressed.

Algorithms↗
PubMed1998

Vinorelbine/gemcitabine in advanced non-small cell lung cancer (NSCLC): a phase I trial.

Vinorelbine and gemcitabine are both active as single agents in advanced non-small cell lung cancer (NSCLC). Because of their different mechanisms of action, good tolerability and possible administration on an out-patient basis, vinorelbine/gemcitabine should be an interesting combination for palliative chemotherapy. Thus, we initiated a phase I dose-escalation trial in order to determine the maximum tolerated doses of vinorelbine/gemcitabine that can be administered without haematopoietic growth factors, the dose-limiting toxicities and the most frequent side-effects of this novel combination. 40 chemotherapy-naïve patients with advanced NSCLC were treated with different doses of vinorelbine/gemcitabine on days 1, 8 and 15, and this treatment cycle was repeated on day 29. Vinorelbine and gemcitabine were escalated from 10 to 30 mg/m2 and 600 to 1200 mg/m2, respectively. A total of 63 treatment cycles were administered and 27 patients received at least two treatment cycles. Dose-limiting toxicities were leucopenia plus thrombocytopenia (2 patients) and mucositis (1 patient). The maximum tolerated dose was established at 25 mg/m2 vinorelbine combined with 1200 mg/m2 gemcitabine. Frequent side-effects were leucopenia, anaemia, nausea/vomiting, flu-like symptoms, skin rashes and elevation of liver enzymes. The recommended phase II doses are 20-25 mg/m2 vinorelbine combined with 1000-1200 mg/m2 gemcitabine on days 1, 8 and 15, but myelosuppression will have to be carefully monitored.

Adult↗
PubMed1998

Stress fractures of the femoral neck.

Stress fractures of the femoral neck are uncommon injuries. In general these injuries are seen in two distinct populations: (1) young, healthy, active individuals such as recreational runners, endurance athletes, or military recruits; and (2) the elderly who have osteoporosis. Stress fractures can be classified as either fatigue or insufficiency fractures and result from untoward cyclic loading or impaired bone quality. The key to treatment is early diagnosis, which may require scintigraphy or magnetic resonance imaging. Nondisplaced compression type stress fractures can be treated nonoperatively with protected weight-bearing and frequent radiographic followup. Tension type stress fractures should be stabilized internally to prevent the adverse consequences of fracture displacement.

Age Factors↗
PubMed1997

Phase II trial of gemcitabine in advanced non-small-cell lung cancer.

Gemcitabine has shown activity in different solid tumors. In the present study we have evaluated its efficacy in 32 patients with advanced non-small-cell lung cancer in a phase II trial. Gemcitabine (1250 mg/m2) was given intravenously as a 30-minute infusion on days 1, 8 and 15. Cycles were repeated every 4 weeks. Twenty-nine patients were evaluable for response and all patients for toxicity. Partial remissions and stable disease were seen in 4 (14%) and 13 (45%) patients, respectively. Improvement of symptoms occurred in 54% of the patients. Side effects were mild and included predominantly leukopenia and thrombocytopenia. In conclusion, gemcitabine is active and well tolerated in patients with advanced non-small-cell lung cancer.

Adult↗
PubMed1997

Adjunctive interferon-alpha-2c in stage IIIB/IV small-cell lung cancer: a phase III trial.

Preliminary studies have shown bioactivity of interferons (IFNs) in the treatment of small-cell lung cancer (SCLC). The aim of the present study was to determine whether, in patients with advanced SCLC, a combination of recombinant IFN-alpha-2c and standard induction chemotherapy would improve response rates and survival at acceptable toxicity. Of the 85 patients recruited by 11 centres in Austria, 77 were evaluable for response after induction therapy; of these, 43 were randomized to receive the combined treatment (three cycles each of cyclophosphamide/vincristine/doxorubicin and cisplatin/etoposide plus subcutaneous IFN-alpha-2c), and 34 received chemotherapy alone. After the induction phase, patients in the IFN arm had higher rates of complete (30 vs 15%) and partial remission (42 vs 29%) than those who received chemotherapy alone. Accordingly, there was a lower rate of progressive disease in the interferon arm (21 vs 44%; p < 0.05). Whilst there were no significant differences in time to progression (7.6 vs 5.4 months) patients in the IFN arm survived longer than those in the chemotherapy arm (p < 0.02). Six of the patients treated with IFN (14%) survived for more than 2 yrs, whereas none in the chemotherapy arm did. We conclude that the addition of interferon-alpha-2c to induction chemotherapy may improve response rates and survival in advanced small-cell lung cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Alveolar macrophages of patients with adult respiratory distress syndrome express high levels of heat shock protein 72 mRNA.

Adult respiratory distress syndrome (ARDS), a multifactorial disease with poor prognosis, is characterized by an accumulation of inflammatory cells within the airspaces of the lungs. There is evidence that alveolar macrophages (AM) are involved in the pathogenesis of this pulmonary disease. It has been demonstrated that AM synthesize heat shock proteins (HSPs) after exposure to certain stress factors. Increasing evidence suggests that HSPs could confer protection against oxidative injury, noxious molecules, and bacterial toxins. In stressed cells HSP 72 appears to be essential for survival during and after exposure to cellular injury. The aim of this study was to evaluate the magnitude of HSP 72 expression by human AM of patients with ARDS and correlate that with respiratory burst activity. Bronchoalveolar lavage was performed in six ARDS patients, 10 patients with high risk for developing ARDS, and two patients who underwent bronchoscopy for other reasons. Spontaneous ex vivo expression of HSP 72 in AM could be demonstrated by immunocytochemistry. Total RNA as well as poly(A)-rich mRNA were extracted from recovered AM and analyzed by Northern blot and slot blot using a human HSP 72-specific probe. Signals of slot blot were analyzed by densitometry and expressed as relative levels of HSP 72 mRNA of stressed (42 degrees C) HT 1080 control cells. Significantly (p < .001) higher levels of HSP 72 mRNA were measured in patients with ARDS (96.2 +/- 9.5 relative levels) in comparison to those not developing this syndrome (46.0 +/- 4.2). With regard to respiratory burst activity of AM in patients with ARDS, there was a negative correlation between HSP 72 expression and reactive oxygen species production. The AM of patients with ARDS with high relative levels of HSP 72 expression showed low respiratory burst activity. A predictive value for disease severity of high level of HSP 72 mRNA in AM in patients at risk for ARDS has to be evaluated by future studies. This demonstration of HSP 72 expression ex vivo suggests a protective role of HSP response against endo/exogenously generated stress factors in AM.

Adult↗
PubMed1996

Tibiotalar contact area and pressure distribution: the effect of mortise widening and syndesmosis fixation.

An unconstrained cadaver ankle model was designed to reevaluate the effect of ankle mortise widening and syndesmotic fixation on the load-bearing characteristics of the tibiotalar joint. Tibiotalar contact area, centroid shift, and mean contact pressure were quantified using a pressure-sensitive film technique. Six fresh-frozen below-knee amputation specimens were axially loaded with 500 N in three positions: neutral, 10 degrees of dorsiflexion, and 20 degrees of plantarflexion. The tibiotalar contact area and centroid position for each specimen in its intact state were first determined and then compared with values obtained after syndesmotic fixation, mortise widening of 2 and 4 mm, and deep deltoid ligament transection. Syndesmotic fixation significantly decreased joint contact area but did not consistently affect centroid position. However, unlike earlier studies, which used more constrained ankle fracture models, mortise widening with or without deltoid rupture was not found to significantly affect contact area, centroid position, or joint contact pressure. When statically loaded, the talus moved to its position of maximal congruence in the mortise, rather than displacing laterally along with the lateral malleolus.

Ankle Joint↗
PubMed1996

[Practicability, effectiveness and tolerance of a standardized prepared theophylline infusion].

The practicality, efficacy, and tolerance of a standardized, ready-to-use theophylline solution (Eloasthmin, Leopold Pharma, Graz) was studied on 33 patients with bronchial asthma and/or chronic obstructive bronchitis (COPD) (19 males, 14 females) aged 19 to 79 (median 50) years. Eloasthmin a ready-to-use pure theophylline solution containing no auxilliary substances, contains one gram theophyllin per liter in a hypotonic (2/3) NaCl solution. The infusion therapy was carried out in patients in an acute stage of their chronic obstructive ventilation dysfunction. The therapy was carried out for 2 to 4 days at a dose of 400 to 1000 mg theophylline per day, so that theophylline blood levels remained within the therapeutic range of 8 to 20 mg/ml. A highly significant improvement (p < 0.001) of lung function parameters was seen during treatment: VC before therapy = 2.46 l, after therapy = 3.36 l; FEV 1 before therapy = 1.34 l, after therapy = 2.04 l; and PEF before therapy = 3.48 l/s after therapy = 5.13 l/s. Since most patients also received concomittant medication (beta 2-sympathomimetica and/or glucocorticoids), it was difficult to differentiate the specific efficacy of the theophylline.

Adult↗
PubMed1995

Fracture blister formation: a laboratory study.

A biomechanical study was performed to examine a proposed mechanism of fracture blister formation. Sixty cadaver ankle skin specimens were subjected to several levels of uniaxial strain and examined histologically. Dermal-epidermal separation patterns similar to those found histologically in previous studies of biopsied fracture blisters were seen in specimens strained 152% and greater. These findings support the hypothesis that fracture blisters can result from strain developed in the skin during initial fracture deformation.

Biomechanical Phenomena↗
PubMed1995

Deltoid ligament forces after tibialis posterior tendon rupture: effects of triple arthrodesis and calcaneal displacement osteotomies.

Deltoid ligament forces were studied after observing deltoid ligament insufficiency in several post-triple arthrodesis patients. Six fresh-frozen, below-knee amputation specimens were axially loaded. The results demonstrate that a properly positioned triple arthrodesis produced deltoid ligament forces that were similar to those seen with an intact tibialis posterior tendon. A triple arthrodesis in combination with a lateral displacement calcaneal osteotomy produced deltoid ligament forces that were 76% greater than those seen with the intact tibialis posterior tendon (P < .05). A triple arthrodesis in combination with a medial displacement calcaneal osteotomy produced deltoid ligament forces that were 56% less than those seen with the lateral displacement calcaneal osteotomy (P < .01). Patients with longstanding ruptures of the tibialis posterior tendon and associated peritalar subluxation/dislocation may have less than optimal clinical results after triple arthrodesis, unless the hindfoot can be properly reduced, due to persistent elevated forces in the deltoid ligament and resulting ligament laxity. This study suggests that a medial displacement calcaneal osteotomy in combination with a triple arthrodesis may be a viable treatment when the hindfoot cannot be positioned properly.

Ankle Joint↗
PubMed1995

Histology and histomorphometric analysis of the normal and atrophic heel fat pad.

Light and electron microscopy was used for a histologic examination of normal heel fat pads and atrophic heel fat pads from patients with peripheral neuropathies. Histomorphometric analysis revealed an average 30% smaller mean cell area and 16% smaller mean cell diameters in the atrophic pads compared with the normal heel fat pads. Septal walls in the atrophic fat pads were often fragmented and approximately 75% wider than normal. Perineural fibrosis was also found in the atrophic heel fat pads. The Verhoeff elastic staining technique was used to determine the relative percentage of collagen to elastic tissue within the septae. No significant differences were noted between the normal and atrophic heels. The ultrastructure of the adipocytes from the normal and atrophic heel pads was similar to those found in abdominal subcutaneous fat. Lipid droplets of variable size and density thin the center of the adipocyte were surrounded by a thin border of cytoplasm. The interphase between adipocytes contained fine collagen and elastic fibers.

Adipose Tissue↗