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Biomedical subjects

M Langer

Publications and source records attributed to M Langer.

At least 181 records · Page 10Linked to original sources
PubMed1996

[Gastroenterology in Germany--determination of current status and perspectives. Results of a survey among members of the German Society of Digestive and Metabolic Diseases].

UNLABELLED: The present survey carried out among the members of the German Society of Gastroenterology and Metabolism (GSGM) was intended 1. to provide information on a) age, professional experience and nature of present activities, b) the service spectrum, c) career prospects, and 2 to reflect the views of those questioned on a) the ability of non-gastroenterologists to furnish gastroenterological services, b) the performance of invasive procedures on an ambulatory basis, c) requirements to be met by gastroenterological training, d) quality assurance measures, and e) the public image of the specialty gastroenterology. METHOD: A questionnaire was sent to the members of the GSGM, of whom 629 responded and whose questionnaires were evaluated. RESULTS: The median age of the responders was 48,2 years, median duration of professional activity was 15 years; 73% work in a hospital setting. Some 76-88% of those working in hospitals consider their future activities to be in the hospitals. Provided that strict, in part yet to be defined, specialty-related conditions are met, gastroenterological services can also be provided by non-gastroenterologists. Some 50% of the responders were against the performance of invasive endoscopic procedures on an ambulatory basis (e.g. EPT, lithotripsy, stent implantation). In the opinion of the majority, the number of doctors undergoing specialist training with the aim of becoming qualified gastroenterologists should not be limited. The majority of responders were also in favour of quality assurance measures as well as clinical research in this area. Almost three-quarters of the responding members of the GSGM perceived shortcomings in the public image of gastroenterology. CONCLUSION: The analysis of the results of the present survey indicate prospects for the future, but also a need for action in the field of the specialty gastroenterology.

Ambulatory Surgical Procedures↗
PubMed1996

[Vascular stents and development of endoluminal therapy of aortic aneurysm].

Intravascular stents have played an important role in improving early and long-term patency in the treatment of arterial occlusive disease, particularly in the iliac arteries after failed balloon angioplasty. The development of covered stents opened a new dimension for non-operative therapy of aneurysmal disease. Transluminally placed stent-grafts represent a blending of technologies with use of intravascular stents and prosthetic vascular grafts. Stent-graft combinations were first envisioned by Dotter in 1969 as devices that would ultimately be useful to treat aneurysms, pseudoaneurysms and arterio-venous fistulas. Animal studies of endovascular stented grafts demonstrated the potential feasibility of these devices to treat arterial lesions. Parodi et al. first implanted stent-grafts in patients with abdominal aortic aneurysms and demonstrated its clinical feasibility. Newly developed stent-grafts allowed to treat successfully a limited number of patients with AAA. Although much has been reported about the healing properties of prosthetic grafts in extraluminal locations, there are only little data concerning the arterial response to a prosthetic graft placed within the lumen or anchored into the wall of a human vessel. Therefore, long-term evaluation of these new devices will be crucial.

Angioplasty, Balloon↗
PubMed1996

[Initial clinical experiences with endovascular stent-grafts for treatment of infrarenal abdominal aortic aneurysm].

With a series of 34 transluminal stent-graft procedures, we assessed the feasibility and clinical effectiveness of a new stent-graft for the treatment of infrarenal abdominal aortic aneurysms (AAAs). We treated 34 male patients (mean age 71 years) with straight of bifurcated nitinol stents covered with woven Dacron graft material for infrarenal excentric saccular AAA (n = 3) or AAA involving the bifurcation and the common iliac arteries (n = 31). The 18-F delivery system was advanced via a surgical arteriotomy and the stent-graft was placed under fluoroscopic control. Follow-up period ranged from 8 days to 13 months. The implantation of the stent-grafts was technically successful with exclusion of AAA in 31/34 cases (91%). In 2 patients, there was a persisting leak at the distal end of the endoprosthesis after treatment; in another, marked coiling of the external iliac artery impeded the delivery system to be advanced and consecutive rupture resulted in conversion to surgical repair. Other procedure-related complications were acute hepatic failure due to gastric bleeding in a patient with liver cirrhosis, graft occlusion due to emboli originating from the left atrium (n = 1), local hematoma (n = 1), and AV-fistula (n = 1) requiring surgery. A post-implantation syndrome with leucocytosis and elevated C-reactive protein was observed in all patients. Endoluminal repair of infrarenal AAA with use of Dacron covered nitinol stent-grafts is feasible, safe and clinically effective. However, careful long-term evaluation is necessary before it will become clinical practice.

Aged↗
PubMed1996

[Daily survey of procedures as markers of resources utilization].

OBJECTIVE: To assess and to follow along the time-span of ICU stay the process of resources allocation and utilization. DESIGN: Prospective study. PATIENTS: A cohort of 778 patients consecutively admitted to 7 multipurpose general ICU in the Milano area were enrolled in a survey of the daily performed interventions/procedures. MEASUREMENTS AND MAIN RESULTS: The majority of diagnostic procedure/interventions were performed during the first two days. The number and quality of interventions were transferred into points obtaining a score system in non-monetary units. The resource allocation process shows a regular trend in the sub-intensive patients who were only monitorized. On the contrary the 258 patients who were intensively treated and survived show a phase of high resource-consumption (about 30 daily points: roughly twice the score of monitorized patients) then followed by a post-intensive phase with a resource consumption resulting in a daily score absolutely equal to the sub-intensive patients. The intensive patients who die show a significantly higher score than survived patients. Both daily and cumulative scores do not show differences among different type of patients. CONCLUSION: The evaluation of the process of resources allocation, even if in non-monetary units enables the knowledge of the trend of ICU costs and allows the elaboration of the appropriate budget mechanism.

Cohort Studies↗
PubMed1995

Comparison of simulated annealing algorithms for conformal therapy treatment planning.

PURPOSE: The efficiency of four fast simulated annealing algorithms for optimizing conformal radiation therapy treatment plans was studied and the resulting plans were compared with each other and to optimized conventional plans. METHODS AND MATERIALS: Four algorithms were selected on the basis of their reported successes in solving other minimization problems: fast simulated annealing with a Cauchy generating function, fast simulated annealing with a Lorentzian generating function, variable step size generalized simulated annealing (VSGSA), and very fast simulated reannealing (VFSR). They were tested on six clinical cases using a multiple beam coplanar conformal treatment technique. Relative beam weights were computed that maximized the minimum tumor dose subject to dose-volume constraints on normal organ doses. Following some initial tuning of the annealing parameters, each algorithm was applied identically to each test case. Optimization tests were run using different random number sequences and different numbers of iterations. RESULTS: The VSGSA algorithm consistently produced the best results. Using long run times, it generated plans with the highest minimum tumor dose in five of the six cases. For the short run times, the VSGSA solutions averaged larger minimum tumor doses than those of the other algorithms for all six patients, with increases ranging from 0.4 to 5.9 Gy. For three of the patients, the conformal plan gave a clinically significant increase in the minimum tumor dose over the conventional plan, ranging from 8.2 to 13.0 Gy. In two other cases, there was little difference between the two treatment approaches. For one case, the optimized conventional plan was much better than the conformal plan because the conventional beam arrangement included wedges, which offset the multiple beam advantage of the conformal plans. CONCLUSIONS: For equal computing times of both long and short duration, the VSGSA algorithm consistently produced conformal plans that were superior to those produced by the other algorithms. The simple conformal technique used in this study showed a significant potential advantage in the treatment of abdominal tumors. In three of the cases, the conformal plans showed clinically important increases in tumor dose over optimized conventional plans.

Abdominal Neoplasms↗
PubMed1995

The transjugular intrahepatic portosystemic stent-shunt procedure for refractory ascites.

BACKGROUND: Previous studies have suggested that the transjugular placement of an intrahepatic stent to establish a portosystemic shunt is an effective treatment of uncomplicated ascites accompanying variceal bleeding. We studied the stent shunt for use in patients with liver cirrhosis and ascites refractory to medical treatment. METHODS: Fifty of 62 consecutive patients with cirrhosis and refractory ascites (18 with Child-Pugh class B liver disease and 32 with class C) were treated with the stent shunt--an expandable stent of metallic mesh placed between a major branch of the portal vein and one of the hepatic veins. Patients were followed for a mean (+/- SD) of 426 +/- 333 days. Those with advanced cancer, severe heart failure, or severe liver failure were excluded. RESULTS: The stent shunt was successfully placed in all patients and reduced the pressure gradient between the portal vein and the inferior vena cava by an average of 63 percent. Thirty-seven patients (74 percent) had complete responses (total remission of ascites within three months), and nine patients (18 percent) had partial responses (ascites detected by ultrasound but with no need for paracentesis). Four patients did not respond, including two who died within two weeks of shunt placement. After the procedure, 25 patients had hepatic encephalopathy, as compared with 20 patients before the procedure; although encephalopathy improved in 3 patients, new encephalopathy developed in 8 patients. In the 28 of the 33 patients followed for more than six months who were evaluated, the mean serum creatinine concentration was 1.5 +/- 0.09 mg per deciliter (133 +/- 8 mumol per liter) before placement of the stent shunt, 1.5 +/- 1.6 mg per deciliter (133 +/- 141 mumol per liter) one week after the procedure, and 0.9 +/- 0.3 mg per deciliter (80 +/- 27 mumol per liter) after six months (P = 0.008 for the comparison of concentrations before and six months after the procedure). Renal function did not improve in the six patients with organic kidney disease. Procedure-related complications developed in 16 patients, including intraabdominal bleeding requiring blood transfusions in 2 patients. Thrombotic occlusion of the stent shunt occurred within two weeks in 5 patients, and later insufficiency of the shunt occurred in 16 patients, including 12 with recurrence of ascites after complete remission. During followup, an additional 29 patients died--10 of progressive liver disease and 19 of other causes. Survival for at least one year was associated with a patient's being under 60 years of age, having a serum bilirubin level before placement of the stent shunt of less than 1.3 mg per deciliter (22 mumol per liter), and having a complete response. CONCLUSIONS: Our findings in an uncontrolled prospective study suggest that the transjugular intrahepatic porto-systemic stent-shunt procedure was an effective treatment for many patients with liver cirrhosis and refractory ascites, but mortality from underlying diseases was substantial.

Ascites↗
PubMed1995

Very fast simulated reannealing in radiation therapy treatment plan optimization.

PURPOSE: Very Fast Simulated Reannealing is a relatively new (1989) and sophisticated algorithm for simulated annealing applications. It offers the advantages of annealing methods while requiring shorter execution times. The purpose of this investigation was to adapt Very Fast Simulated Reannealing to conformal treatment planning optimization. METHODS AND MATERIALS: We used Very Fast Simulated Reannealing to optimize treatments for three clinical cases with two different cost functions. The first cost function was linear (minimum target dose) with nonlinear dose-volume normal tissue constraints. The second cost function (probability of uncomplicated local control) was a weighted product of normal tissue complication probabilities and the tumor control probability. RESULTS: For the cost functions used in this study, the Very Fast Simulated Reannealing algorithm achieved results within 5-10% of the final solution (100,000 iterations) after 1000 iterations and within 3-5% of the final solution after 5000-10000 iterations. These solutions were superior to those produced by a conventional treatment plan based on an analysis of the resulting dose-volume histograms. However, this technique is a stochastic method and results vary in a statistical manner. Successive solutions may differ by up to 10%. CONCLUSION: Very Fast Simulated Reannealing, with modifications, is suitable for radiation therapy treatment planning optimization. It produced results within 3-10% of the optimal solution, produced using another optimization algorithm (Mixed Integer Programming), in clinically useful execution times.

Algorithms↗
PubMed1995

Breath-hold projection magnetic resonance-cholangio-pancreaticography (MRCP): a new method for the examination of the bile and pancreatic ducts.

Breath-hold MR cholangio-pancreaticography using the RARE method was evaluated as a noninvasive alternative to direct cholangio-pancreaticography in 30 healthy volunteers and in 30 patients with various diseases of the respective duct systems. In contrast to 3D MR cholangiography, RARE MRCP generates projection images requiring a 4-s acquisition time and no postprocessing. Diagnostic information gained from the cholangio-pancreaticograms was fully equivalent to that of conventional x-ray imaging by invasive procedures. Additional information was gained whenever endoscopic access was impossible and/or cystic malformations were present.

Adult↗
PubMed1995

Early metabolic treatment after liver transplant: amino acid tolerance.

OBJECTIVE: We investigated the amino acid (AA) tolerance during Total Parenteral Nutrition (TPN) in adult patients undergone liver transplant (LTX). DESIGN: The treatment (Glucose and AA), induced on the 2nd postoperative day, was later maintained with 27 kcal/kg Ideal Body Weight (IBW) as glucose and 0.12 (12 patients: protocol #1), 0.18 (10 patients: protocol #2) and 0.25 g nitrogen (N)/kg IBW (13 patients: protocol #3) till end of the 6th postoperative day. The N intake was sequentially modified in protocol #2 and #3 to increase the supply of the amino acid (AA) that resulted in an infusion plasma level below the expected "normal" range (between 1 and 1.6 times the overnight fasting plasma level of volunteer). PATIENTS: 35 consecutive adult patients without diabetes and organ failures for the entire study period. MEASUREMENTS: Plasma AA profile was measured before LTX and at the last TPN day under continuous infusion. During #1 and #2 protocol, many AA resulted below or at the lower range of the norm while, during 0.25 gN/kg IBW infusion, the majority of the administered AA significantly increased with respect to reference values. Nevertheless, they remained in the "normal" plasma range indicating that they were supplied in an optimal amount (particularly the aromatic and sulphurated ones, potentially toxic if liver function is impaired, and the branched chain AA (BCAA) given at consistent dosage: 0.5 g/kg). Arginine resulted significantly increased (Arg: 1.9 times the reference) and cystine (Cys: 0.45), serine (Ser: 0.8) and taurine (Tau: 0.85) remained significantly lower than "normal" as well as the not administered citrulline (Cit: 0.58) and alfa amino butyric acid (Aba: 0.41). The AA (and calorie) load almost balanced the N losses during the 5th (0.411 +/- 0.038) and 6th study day (0.305 +/- 0.019 gN/kg). CONCLUSIONS: 0.25 gN/kg could be considered the minimum N load in the uncomplicated adult LTX recipients, for reassuring a balanced plasma AA pattern and body N turnover in the early postoperative phase.

Adolescent↗
PubMed1995

The Italian SEPSIS study: preliminary results on the incidence and evolution of SIRS, sepsis, severe sepsis and septic shock.

This prospective, multicenter, epidemiological study was carried out in 99 Italian ICUs, distributed throughout the country, from April 1993 to March 1994. In the study, we applied the new ACCP/SCCM classification system for sepsis (SIRS, sepsis, severe sepsis and septic shock) and determined the prevalence, incidence, evolution and outcome of these categories in critically ill patients. The preliminary analysis of 1101 patients showed that on admission SIRS accounted for about half of the diagnoses (52%) with sepsis, severe sepsis and septic shock accounting for 4.5%, 2.1% and 3% of patients, respectively. Patients with severe sepsis or septic shock more frequently had high SAPS scores than patients without sepsis. Mortality rates were similar in patients with SIRS (26.5%) and without SIRS or infection (24%), but rose to 36% in patients with sepsis, to 52% in those with severe sepsis and to 81.8% in those with septic shock. Sepsis, severe sepsis and septic shock were more common in patients with medical diagnoses, and neither severe sepsis nor septic shock was observed in trauma patients. With respect to evolution, the incidence of septic shock was progressively higher in patients admitted with more severe "sepsis-related" diagnoses, while only a trivial difference in rates of incidence was observed between SIRS patients and those admitted without SIRS or any septic disorder (nil). The breakdown of the various ACCP/SCCM "sepsis-related" diagnoses at any time during the study was: SIRS in 58% of the population, sepsis in 16.3%, severe sepsis in 5.5% and septic shock in 6.1%. It seems reasonable to expect from the final evaluation of our study answers to the questions raised by the ACCP/SCCM Consensus Conference about the correlations between "sepsis-related" diagnosis, severity score, organ dysfunction score and outcome.

Hospital Mortality↗
PubMed1995

Haemangiomatosis in children: value of MRI during therapy.

MRI findings of 18 examinations of six children with haemangiomatosis and one with extended arteriovenous malformation are reported. Structures involved were the liver, liver and lung, periorbital area and the thigh. Response to interferon therapy, in particular, was assessed. With MRI the disease can be characterized and the extent of the lesions and size of the haemangiomas measured. Coronal views provide excellent demonstration of the involved structures in liver and lung haemangiomatosis. Two children showed response to interferon therapy with a reduction in lesion size and subsequently in number. Signal intensity decreased slightly on T2-weighted images. During treatment, however, no definitive fibrotic zones were seen. Following complete regression, signal intensity of the liver parenchyma was homogeneous in both weightings, that is, no fibrotic areas were visible 18 months after the beginning of treatment. Two children showed no response and one child died from congestive cardiac failure. The periorbital haemangioma was reduced in size and the lesion in the thigh might be classified as an arteriovenous malformation. In children MRI can replace CT as it is a reliable imaging modality for diagnosing haemangiomatosis and monitoring therapy.

Child↗
PubMed1995

Value of RARE-MRI sequences in the diagnosis of lymphangiomatosis in children.

Three patients suffering from extensive cavernous lymphangiomatosis are presented here. They were examined by MRI using RARE-MR hydrography (rapid acquisition with relaxation enhancement) as well as conventional spin-echo sequences. RARE sequences, which depict each fluid-filled lymphatic space, can be used for screening. RARE-sequences help to shorten investigation time, particularly in cases involving the skeleton. The imaging strategy can be changed according to the results of this sequence. It may be performed prior to spin-echo sequences and facilitates follow-up investigations. RARE sequences distinguish between lymphangiomatosis and hemangiomatosis, or a combination of the two.

Adult↗
PubMed1995

[NMR tomographic measurement of femoral ante-torsion and tibial torsion].

PURPOSE: A new MRI method for the measurement of femoral torsion and tibial torsion is presented. METHODS: Axial images were generated using a standard gradient echo sequence (FLASH 2D). Otherwise measurement of femoral and tibial torsion was performed according to an established CT method. RESULTS: The torsion angles measured using MRI were in accordance with the angles measured using the CT method. The MRI method was not more time-consuming than the CT method. CONCLUSION: In respect of radiation exposure, MRI determination of femoral and tibial torsion should be considered particularly in children and patients who have to undergo repeated torsion measurements.

Adolescent↗
PubMed1995

[Psychosocial prognostic factors for refertilization or IvF after tubal sterilization].

In a psychosomatic study we interviewed 33 women who had undergone tubal anastomosis or IvF after tubal ligation. As a control group we chose a randomised sample of 45 women after elective tubal ligation. We used a semi-structured interview and the Giessen-test as psychometric instruments. According to the leading indication for reanastomosis, we allocated women to one of 2 groups: 21 patients had found a new partner (R-partner), 12 mentioned experiences of loss (R-loss). The groups were well comparable in respect of sociodemographic items, but showed relevant differences in psychological variables, like motivation for and time for deliberation to sterilisation or age difference between partners. Women of the R-partner group were highly satisfied with tubal reanastomosis as compared to R-loss subjects. Satisfaction with the procedure was basically independent of an actual pregnancy. Women experienced the two methods in different, rather specific ways. Cluster analysis of the Giessen-test result confirmed group allocation. We conclude that experiences of loss as a leading reason for tubal reanastomosis are unfavourable prognostic factors. IvF has an unfavourable prognosis in women with the intention to restore the mutilated body image. Preoperative counselling by a psychotherapeutically trained counsellor seems mandatory.

Adult↗
PubMed1995

[Uterus unicornis with rudimentary horn and ipsilateral kidney agenesis: clinical symptoms and therapy].

We report on a 21-year old patient with unicornuate uterus with a rudimentary non-communicating horn (Buttram II-A-1-b), haematosalpinx, associated with ipsilateral ureteranomaly and renal agenesis. In this case we illustrate symptoms, diagnosis and therapy. Despite extensive diagnosis surgical methods finally have to be adapted to the anatomical situation during operation. A short review of literature and embryology is given, more diagnostic preoperative measures are discussed.

Adult↗
PubMed1995

Digitization and postprocessing of plain-film radiographs for assessment of stone fragmentation after extracorporeal shockwave lithotripsy.

In 50 patients treated for urolithiasis by extracorporeal shockwave lithotripsy (ESWL++), the radiographs taken before and 1 day afterward were initially assessed by conventional radiography and subsequently after standardized digitization and postprocessing. Clinical outcome and passage of stone fragments were reevaluated 3 weeks after ESWL. Using specially developed software routines, new disintegration parameters could be obtained by detecting the number of relevant minima in light-intensity distribution along the length axis of the concrement in digitized images. Comparing the digitized images before with those after ESWL, the concremental surface and axial length in digitized images on average showed no statistically significant difference. However, the number of visually and automatically detected light-intensity minima of the concrement region in digitized images obtained 1 day after ESWL was significantly higher than prior to ESWL and correlated significantly with the number of fissure lines in the conventional images. These new features in digitized images showed a high sensitivity in predicting later passage of stone fragments. Moreover, in six of the seven patients without detectable fissure lines in the early conventional radiographs but obvious signs of concretemental disintegration 3 weeks after ESWL, there was an increase in the number of light-intensity minima in the digitized images 1 day after ESWL. Our findings indicate that this method of digitization and post-processing of radiographs may improve the assessment of ESWL effectiveness by improving standardization in the analysis of all surveyed parameters and by offering new relevant disintegration measures.

Adult↗
PubMed1995

The reducing stent: treatment for transjugular intrahepatic portosystemic shunt-induced refractory hepatic encephalopathy and liver failure.

PURPOSE: To examine the efficacy of a stent device in reducing the diameter of transjugular intrahepatic portosystemic shunts (TIPS) in patients with progressive liver failure or with shunt-induced hepatic encephalopathy. MATERIALS AND METHODS: Seven patients with TIPS (four with severe hepatic encephalopathy, three with progressive liver failure) underwent transjugular implantation of a stent designed to reduce the flow through the original TIPS channel. RESULTS: Implantation of the reducing stent proceeded without complication. Duplex sonography showed that stent flow decreased by 41% +/- 18 (mean +/- standard deviation). The four patients with hepatic encephalopathy showed substantial improvement. Concentrations of plasma ammonium and serum bilirubin improved considerably. In contrast, functional impairment progressed in the three patients treated for liver failure. The patients soon died. CONCLUSION: With the limited experience of treating these seven patients, the authors suggest that shunt-induced hepatic encephalopathy can be effectively treated with implantation of a reducing stent. Hepatic failure, however, is a deleterious complication that seems to be irreversible.

Aged↗