Biomedical subjects

R Lange

Publications and source records attributed to R Lange.

At least 199 records · Page 11Linked to original sources

PubMed1996

[Percutaneous puncture technique for portofemorosubclavicular venovenous bypass in orthotopic liver transplantation].

UNLABELLED: Portofemoro-axillary bypass systems are commonly used to treat adverse haemodynamic effects during the anhepatic phase of orthotopic liver transplantation (OLT). However, low shunt flows may reduce the efficacy of these bypass systems. In order to improve veno-venous bypass management, a percutaneous cannulation technique (PCT) was used to insert large-bore catheters (21 F) into the left femoral and subclavian veins. This study prospectively addresses the complications of the PCT in 195 adult patients undergoing 203 OLTs. METHODS: The left femoral and subclavian veins were cannulated preoperatively with 21 F single-lumen catheters (DLP, Grand Rapids, MN, USA) using a Seldinger technique. Intra-operatively, the centrifugal pump (Biopump, Biomedicus, Minnesota, USA) and the portal part of the bypass were connected with the femoral and subclavian catheters. Coagulation profiles, shunt flows, haemodynamic parameters, and complications during OLT associated with the bypass system were recorded. RESULTS: Percutaneous cannulation of the left subclavian and femoral veins was successful in 198 (97.6%) patients. Mean portofemoro-subclavian shuntflow was 4.3 (SD 1.3 l min-1). Although cardiac index (shunt 3.91 [SD 1.1] vs pre-shunt 4.42 [SD 1.0] l min-1 m-2, P < 0.05) and oxygen delivery (shunt 496 [SD 111] vs. pre-shunt 562 [SD 153] ml ml-1.m-2, P < 0.05) were not maintained at pre-shunt levels, renal perfusion pressure stayed above 50 mm Hg during the anhepatic phase. Two intra-operative air embolism (0.98%) and one myocardial infarction (0.49%) at the beginning of the anhepatic phase were observed. There were no bleeding complications. CONCLUSIONS: The portofemoro-subclavian bypass can be performed by percutaneous cannulation without additional complications in patients undergoing OLT. Although haemorrhagic complications following central venous catheterisation are reported to occur in patients with haemostatic defects, none of them was observed in this study. Two events of air embolism and one cardiac arrest could not be related to the PCT. In conclusion, femoro-subclavian percutaneous cannulation is a simple, rapid, and safe alternative to commonly used veno-venous bypass systems.

Adult↗

PubMed1996

Long-term treatment of transfusional iron overload with the oral iron chelator deferiprone (L1): a Dutch multicenter trial.

We performed an open, nonrandomized, multicenter phase-II trial to evaluate the efficacy and toxicity of 1 year of treatment with the oral iron chelator deferiprone in 38 mainly nonthalassemic patients with transfusional iron overload. Initial serum ferritin varied between 996 and 11.644 micrograms/l. Patients were treated with 3-6 g of deferiprone daily. Mean urinary iron excretion (UIE) in 36 evaluable patients was 21.0 mg/24 h and was significantly higher in the patients with thalassemia than in those with myelodysplasia. Negative iron balance was achieved in 20 patients (56%). The median duration of treatment was 10 months; due to side effects and other causes only 20 patients completed 1 year of treatment. Mean serum ferritin levels decreased from 3563 micrograms/l at the start of the trial to 2767 micrograms/l at 6 months (26 patients, p < 0.004) and to 2186 micrograms/l at 12 months (20 patients, p < 0.005). Serum ferritin levels normalized in two patients who were no longer transfusion dependent. Deferiprone was clearly not effective in three patients (two with myelofibrosis, one with myelodysplasia). One patient with myelodysplasia developed agranulocytosis after 12 months of treatment; this was rapidly reversible after stopping deferiprone. Three patients had a mild and transient decrease in white blood cell count. Other side effects leading to withdrawal from the trial consisted mainly of nausea (3 patients), arthralgia (2), and skin rash (1). No clinical signs of zinc deficiency were seen, although zinc excretion was increased in three patients. No changes were seen in liver enzymes, creatinine, antinuclear factor, T-cell subsets, cardiac function, visual acuity, and audiogram. Although our results confirm deferiprone as an effective iron chelator in patients with thalassemia and in some patients with other forms of iron overload, there is still some concern about the safety of this drug, which therefore, at this time, should be used exclusively in well-controlled clinical trials.

Adult↗

PubMed1996

Tricuspid valve reconstruction, a treatment option in acute endocarditis.

Tricuspid valve endocardititis is treated surgically by total valve excision or valve replacement. Both procedures are controversial with regard to the hemodynamic consequences and to the long-term prognosis. In the following, results of tricuspid valve repair in acute infective endocarditis are reported and discussed as an additional treatment option. Between January 1988 and December 1993, 118 patients were operated on for acute valve endocarditis at our institution. Eleven of these patients had tricuspid valve endocarditis, isolated (n = 7) or combined with endocarditis of a left-sided valve (n = 4). In the cases with isolated tricuspid valve endocarditis, the indication for surgery was intractable infection in six and hemodynamically relevant tricuspid insufficiency in one out of seven patients. In all patients with associated left-sided endocarditis, the indication was hemodynamic deterioration. In eight patients the tricuspid valve endocarditis was treated as follows: debridement, vegectomy, patch reconstruction of the cusps, reducing the cusps to two. In three patients reconstruction was not possible because of extensive involvement of all parts of the valve, including the valve ring and the papillary muscles. In these patients primary valve replacement (n = 1) or valve excision with secondary replacement (n = 2) was performed. In four patients tricuspid reconstruction was combined with mitral (n = 1), aortic (n = 1) or double valve replacement (n = 2). Postoperatively, signs of infection vanished in all surviving patients (n = 10) and tricuspid valve endocarditis healed without recurrences. Implanted prosthetic material did not lead to recurrent infection. One patient died early postoperatively after valve excision, in septic shock and multi-organ failure. In seven patients late echocardiographic follow-up showed tricuspid regurgitation grade 0 in three patients, I in two, II in one and III in one. Our results suggest that valve repair is a reasonable treatment option for tricuspid valve endocarditis in all cases with localized infection of the valve. Only if extensive valve destruction excludes valve repair, would we now favor primary valve replacement over simple valvulectomy. In all other cases primary valve reconstruction is the treatment of choice for tricuspid valve endocarditis, if surgery is indicated.

Acute Disease↗

PubMed1996

Surgical treatment of acute endocarditis of the aortic valve with paravalvular abscess: considerations justifying the use of mechanical replacement devices.

OBJECTIVE: Early recurrency after surgery for acute endocarditis is a life-threatening complication. Allograft valves are supposed to have a higher resistance to recurrent infection, thus several authors claim them to be the replacement device of choice in cases of aortic endocarditis. However, allografts have two major drawbacks: their availability is limited, and most of the patients require reoperation for graft calcification of degeneration. Until now there has been no prospective study analysing whether early recurrency after surgery of acute endocarditis is associated with the mechanical valve per se or with factors related to the surgical technique or postoperative care. PATIENTS AND METHODS: We present a prospective study on 36 consecutive patients with acute endocarditis of the aortic valve with paravalvular abscesses. In this series, there were 5 women and 31 men with a mean age of 50.3 years. All patients were operated before a course of antibiotic therapy was completed. Abscesses were radically resected and the cavities closed either with direct suture or, if not possible, with Dacron patches. For aortic valve replacement, a mechanical valve was used in every patient. RESULTS: The early mortality in this series was 14%, only one patient experienced recurrent endocarditis and underwent reoperation. The results compare well with those achieved after valve replacements with allograft valves. CONCLUSION: We conclude that, even in cases of acute endocarditis, replacement of the aortic valve with a mechanical device is an acceptable alternative to the allograft, if radical surgical debridement and adequate antibiotic therapy are performed.

Abscess↗

PubMed1996

The influence of renal function on the pharmacokinetics of unchanged and acyl-glucuroconjugated ketoprofen enantiomers after 50 and 100 mg racemic ketoprofen.

1. To study the effect of renal dysfunction on the pharmacokinetics of ketoprofen (KT), and the possibility of saturation of clearance with elevation of dose, single 50 and 100 mg doses of racemic ketoprofen were administered in a cross-over fashion to seven patients (creatinine clearance, CLCR, 6-72 ml min-1). 2. The stereospecific disposition kinetics of KT enantiomers and their acyl-glucuronide conjugates (KTconj) were determined in plasma and urine for 24 h post-dose. 3. Decreased renal function was associated with a reduced KT oral clearance (CLO) and terminal elimination rate constant (lambda z). Renal clearance of KT conj (CLrconj) was reduced with diminished renal function. 4. Following both 50 and 100 mg doses, there was significant stereoselectivity in the AUC of KT (mean S/R, 0.87 and 0.83, respectively), the AUC of KTconj (mean S/R, 3.4 and 5.2, respectively) and the cumulative urinary excretion of KTconj (mean S/R, 2.1 and 2.2, respectively). The stereoselectivity in renal dysfunction in contrast with the observations previously made in healthy subjects may suggest a disease-related process. 5. CLO remained constant after increasing the dose, indicating linearity in the pharmacokinetics of KT despite reduced CLCR. CLrconj, however, was significantly reduced after the 100 mg dose suggestive of saturation of the urinary clearance and existence of a compensatory pathway. 6. Renal impairment reduces CLrconj and this appears to be the rate-limiting step for clearance of KT due to the observed stronger correlations of CLO with CLrconj than with CLCR. 7. Dose reduction of ketoprofen is indicated only for patients with CLCR < 20 ml min-1.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1996

Fat distribution and cardiovascular risk factors in obese adolescent girls: importance of the intraabdominal fat depot.

The regional distribution of body fat has repeatedly been found to be a significant and independent risk factor for cardiovascular disease in both obese men and women. To determine whether abnormalities in the lipid-lipoprotein profile and systolic and diastolic blood pressure are related to specific fat depots early in the course of obesity, we used magnetic resonance imaging to measure accurately intraabdominal and subcutaneous fat masses in 14 obese [body mass index (BMI; in kg/m2) 30 +/- 1.3] and 10 nonobese (BMI: 21 +/- 0.5) adolescent girls matched for age and Tanner stage of development. Intraabdominal and subcutaneous fat depots were two- to threefold greater in obese than in nonobese girls (P < 0.01). Total cholesterol, triacylglycerol, low-density-lipoprotein (LDL) cholesterol, basal insulin, and systolic and diastolic blood pressure were significantly higher in obese adolescent girls than in control subjects. In obese girls, intraabdominal fat but not BMI or waist-to-hip ratio was highly correlated with basal insulin (r = 0.55, P < 0.04), triacylglycerols (r = 0.53, P < 0.03), and high-density-lipoprotein (HDL) cholesterol (r = -0.54, P < 0.04). Femoral adipose tissue was inversely related to triacylglycerol (r = -0.51) and LDL cholesterol (r = -0.56, P < 0.05) concentrations in obese girls. The study indicates that early in the natural history of obese adolescent girls, cardiovascular risk factors are related to the amount of intraabdominal fat.

Abdomen↗

PubMed1996

Intraspinal epidural sarcoidosis: case report.

OBJECTIVE AND IMPORTANCE: A rare case of lumbar intraspinal epidural sarcoidosis is identified. The rarity of this condition and its clinical presentation are stressed. CLINICAL PRESENTATION: A young Caucasian man presented with the progressive onset of cauda equina syndrome as a result of an expanding mass in the lumbar epidural space compromising the lumbar dural tube from L1 to S1. The patient presented with motor, sensory, and sphincteric dysfunction as a result of this large intraspinal epidural mass. No evidence of systemic illness was noted concomitant with the patient's onset of neurological symptomatology. The patient underwent surgical extirpation of a lumbar intraspinal epidural mass, which was identified histopathologically as sarcoid granuloma. The postoperative work-up included the identification of a mediastinal adenopathy, which was subsequently biopsied and confirmed the diagnosis of sarcoid disease. The patient was treated postoperatively with oral prednisone over a 4-month period. At 7 months postoperatively, the patient had regained gainful employment, the results of his neurological examination were normal, and he was pain-free. INTERVENTION: The patient underwent a multilevel bilateral lumbar laminectomy with facet preservation, extending from L1 to S1, allowing for a gross total removal of the epidural mass. Postoperative oral prednisone was administered as adjuvant therapy for the treatment of multisystem sarcoid disease. CONCLUSION: Aggressive surgical management involving the removal of an extensive epidural mass of the lumbar canal, which was diagnosed as sarcoid disease, coupled with the adjuvant use of oral prednisone has resulted in an excellent outcome for the patient. The results of his clinical examination are now normal, and postoperative radiological imaging reveals no evidence of recurrent or residual disease in the lumbar epidural space. In the unusual case of intraspinal epidural sarcoidosis, the surgical resection of accessible intraspinal epidural masses is recommended, as is the use of oral prednisone postoperatively.

Adult↗

PubMed1996

Posttranscriptional osmotic regulation of the sigma(s) subunit of RNA polymerase in Escherichia coli.

The sigma(s) subunit of RNA polymerase (encoded by the rpoS gene) is a master regulator in a complex regulatory network that governs the expression of many stationary-phase-induced and osmotically regulated genes in Escherichia coli. rpoS expression is itself osmotically regulated by a mechanism that operates at the posttranscriptional level. Cells growing at high osmolarity already exhibit increased levels of sigma(s) during the exponential phase of growth. Osmotic induction of rpoS can be triggered by addition of NaCl or sucrose and is alleviated by glycine betaine. Stimulation of rpoS translation and a change in the half-life of sigma(s) from 3 to 50 min both contribute to osmotic induction. Experiments with lacZ fusions inserted at different positions within the rpoS gene indicate that an element required for sigma(s) degradation is encoded between nucleotides 379 and 742 of the rpoS coding sequence.

Bacterial Proteins↗

PubMed1996

Contextual mediation of perceptions in hauntings and poltergeist-like experiences.

The content of perceived apparitions, e.g., bereavement hallucinations, cannot be explained entirely in terms of electromagnetically induced neurochemical processes. It was shown that contextual variables influential in hallucinatory and hypnotic states also structured reported haunting experiences. As predicted, high congruency was found between the experiential content and the nature of the contextual variables. Further, the number of contextual variables involved in an experience was related to the type of experience and the state or arousal preceding the experience. Based on these findings we argue that a more complete explanation of haunting experiences should take into account both electromagnetically induced neurochemical processes and factors related to contextual mediation.

Arousal↗

PubMed1996

Tolerance of ambiguity and fear of the paranormal.

Houran, et al's model for haunting phenomena predicts that fear of "paranormal phenomena" is associated with intolerance of ambiguity. Consistent with this prediction, ratings by 86 undergraduates (14 men and 72 women) showed a correlation of 33 between the scores on the Anomalous Experiences Inventory and the Rydell Rosen Ambiguity Tolerance Scale.

Adult↗

PubMed1996

Diary of events in a thoroughly unhaunted house.

Two subjects were asked to keep a 30-day journal of occurrences in their residence which are traditionally associated with hauntings and poltergeist-like phenomena. It was expected that the instructions would increase the frequency of perception of unusual or rarely occurring events in their residence, resulting in an attentional and "perceptual contagion effect." As expected, several features of the percipients' observations closely resembled those found in previously reported poltergeist episodes. Most importantly, the distribution of perceived occurrences closely resembled the predicted logistic curve, suggesting that hauntings involve a perceptual process where initial observations "infect" later ones.

Attention↗

PubMed1996

Hauntings and poltergeist-like episodes as a confluence of conventional phenomena: a general hypothesis.

Hauntings and poltergeist-like episodes are argued to be products of contagious reactions to ambiguous environmental or cognitive events. In particular, evidence suggests that the subjective and objective effects reported by percipients are the function of independent, nonparanoraml etiologies whose constitutions have been previously established and described. According to this multivariate model, the labeling of ambiguous events as "abnormal" or "paranormal" initiates the reactive process which is subsequently sustained by perceptual contagion, i.e., flurries of paranormal observations due self-reinforcing attentional processes.

Association Learning↗

PubMed1996

[Biomechanical heart and cardiovascular support].

A surgical association between skeletal muscle and heart muscle dates back to experiments at the beginning of this century. Initially, the use of skeletal muscles aimed at plastic reconstructions of myocardial defects and enhancement of myocardial blood flow. The application of the contractile force of the skeletal muscle failed because of skeletal muscle fatigue. In the late sixties, investigations in muscle physiology demonstrated the "functional plasticity" of muscle tissue: Chronic electrical stimulation induces a transformational process of the cellular organelles, the metabolism, the fiber proteins and the calcium regulatory systems which results in "fatigue resistance" of the muscle. This was is a prerequisite for the application of skeletal muscles for continuous support of the circulation. Biomechanical support of the heart and the circulation is experimentally performed as skeletal muscle ventricles, chronic extraaortic counterpulsation and ventricular and atrial cardiomyoplasty. The electrical stimulation is performed with "burst" impulses, in order to increase the force and the length of contraction. The first clinical application of ventricular cardiomyoplasty is attributed to the French surgeon Alain Carpentier. Clinical investigations show that cardiomyoplasty results in an impressive symptomatic improvement of the patients clinical condition with only moderate changes of objective hemodynamic parameters. Further research will investigate the clinical applicability of the other, thus far only experimental techniques of biomechanical support. The introduction of cardiomyoplasty has induced great scientific interest in all forms of skeletal muscle circulatory support. Close collaboration between basic researchers and clinical investigators is of utmost importance for further developments in this field. The combined international research effort can be expected to yield considerable progress within the forthcoming years.

Animals↗

PubMed1996

[Use of continuous veno-venous high volume hemofiltration (CVVHVH) in patients with multiple organ failure. Principle and applications].

Between 1987 and 1994 in 24 patients suffering from multiple organ failure the new method of continuous high-volume veno-venous hemofiltration (HVCVVH) was performed. Compared with the usual methods of dialysis and hemofiltration the HVCVVH has proven two advantages: at first, it was possible to obtain a high blood flow through the filter powered by a pump. Secondly the fluid withdrawal from the infracardiac body region and the controlled infusion of fluid into the supracardiac veins was possible without decreasing the cardiac preload in patients with severe disorders of volume distribution. 18 of 24 treated patients had a stable circulation without need of catecholamines after the filtration. In 14 of the 24 patients the FiO2 was reduced to 0.3 and decreased during filtration. 13 patients survived the observation time of 30 days, 2 patients died during the procedure of filtration.

Adult↗

PubMed1996

[Value of dynamic cardiomyoplasty].

The value of dynamic cardiomyopathy in the treatment of end-stage heart failure is controversial. After more than 500 patients have been operated worldwide, the indication and the surgical technique have become more uniform, which makes results from different centers eligible for comparison. We performed cardiomyopathy in patients with contraindications for heart transplantation. Between 8.90-2.94, 8 isolated cardiomyopathy-procedures in patients with cardiomyopathy (EF 14-32%, NYHA III) were performed. One patient died in 2 months after surgery. Reported are the results of 7 patients after a mean follow-up of 41.1 +/- 14.1 months. Considerable symptomatic improvement was found in 6 of 7 patients, 3 of whom went back to work. One patient with severe pulmonary hypertension exhibited no improvement. Mean NYHA-class decreased from 3.0 to 1.9 (p < 0.001). Echocardiography showed an increase in fractional shortening in all patients. LV-EF increased from 21.2 +/- 5.2% to 38.1 +/- 15.9% (n = 7, p < 0.015) at 1 year, to 36.6 +/- 17.6% (n = 6, p < 0.05) at two years and to 36.4 +/- 18.9% (n = 5, NS) at three years. Pulmonary artery pressure tended to decrease at rest over time. No significant change in exercise level and maximal O2-consumption upon treadmill testing was observed. One patient died 34 months after the operation from sudden death. Our preliminary results show, that patients after cardiomyopathy may exhibit an impressive clinical improvement with less striking changes of objective hemodynamic parameters. This data is in mutual agreement with all other investigators. According to the current state of experience with cardiomyopathy, the place for this procedure lies in the treatment of patients with end-stage heart failure and contraindications for heart transplantation. We do not consider cardiomyopathy an alternative to heart transplantation, however, it may receive further importance as a bridge to Htx.

Adult↗

PubMed1996

[Dynamic cardiomyoplasty: current status and concepts of the mechanism of action].

Surgical treatment of end-stage heart failure offers heart transplantation as a well established and effective treatment option. In addition, the permanent implantation of left-heart assist-devices is now gaining increasing importance. Yet, both methods also have inherent drawbacks and may not be available to all patients, so that new methods are constantly evaluated. Cardiomyoplasty was introduced into clinical practice 10 years ago, but still lacks general acceptance as a routine method. Worldwide results show a considerable symptomatic improvement with only small effects on systolic cardiac function. Survival rate was significantly improved by careful patient selection. As a mechanism of action the skeletal muscle wrap exerts some active improvement of systolic wall motion of the heart/skeletal muscle-complex. However, probably more important is an acute and chronically persisting shift of the pressure-volume relation to the left. This process results in a "reverse remodeling" of the insufficient heart with an improvement of the "contractility reserve". Cardiomyoplasty is indicated in patients with contraindications to heart transplantation and as a bridge-to-transplantation in patients with ventricular arrhythmia and severely impaired left ventricular function, concomitant with ICD implantation.

Animals↗

PubMed1996

[Therapy of abdominal neuroblastoma in Essen].

Between 1980 and 1996, 74 children aged between 3 and 148 months were operated for neuroblastomas at the University Clinic Essen. A total of 44 patients had a neuroblastoma stage 4, 11 a stage 3, nine a stage 2, two a stage 1, and eight a stage 4s. If there was doubt about the possibility of a primary resection of the tumor, chemotherapy was carried out before surgery. This procedure enabled a complete local resection of the tumor in 46 children. In the postoperative course 29 children died, 25 of which presented tumor progress; four died of complications following bone marrow transplantation. Two children are currently being treated for tumor recurrence, while 43 have survived without tumor recurrence for 15 years. Complete tumor resection produced a better survival rate. If there is any doubt in the primary possibility of complete tumor resection a reduction of the tumor mass can be achieved by chemotherapy. This allows radical surgery can be achieved in significantly more cases.

Adolescent↗

PubMed1996

[Auxiliary liver transplantation in urgent and emergency indications].

This report will focus on seven patients treated with auxiliary liver transplantation. In two cases the indication was severe metabolic disorder and in five cases a fulminant hepatic failure. The clinical course was highly complicated in both cases with metabolic disorder (the transplant was lost, one patient died), but satisfactory in the patients suffering from fulminant hepatic disease: three of five are off immunosuppression, one is under therapy and one patient died of sepsis in the early phase.

Adolescent↗