Biomedical subjects

R Weber

Publications and source records attributed to R Weber.

At least 37 records · Page 2Linked to original sources

PubMed2004

[Inpatient treatment costs of skin diseases. Diagnosis-based cost calculation in a university dermatology clinic].

BACKGROUND AND OBJECTIVE: With the advent of the DRG system, German hospitals are being forced to improve cost transparency and to uncover inefficient structures. METHODS: Diagnosis-based costs were calculated in the Department of Dermatology in the University Hospital of Freiburg for ten samples, each containing 20 cases. By using in-patient files, cost and productivity information for the fiscal year 2000 was attributed to each single case in a bottom-up-approach. The resulting total costs per case were contrasted to their remuneration under the DRG system. RESULTS: Average case costs were determined between EUR 1,339.83 and EUR 5,714.73. With 19.3% to 28.4% of total costs, nursing costs were the biggest single cost factor. Prolonging the length of stay incurred average extra costs of EUR 144.26 to EUR 199.98 per case and day. The correlation of case costs and their corresponding DRG cost weights was modest with r=0,48. There was considerable cost variance within individual DRGs. CONCLUSIONS: The diagnosis-related cost calculation reveals striking cost differences relating to specific diagnoses. This method is more suitable for cost calculations in the hospital than more general approaches.

Academic Medical Centers↗

PubMed2004

Alveolar echinococcosis of the liver in an adult with human immunodeficiency virus type-1 infection.

We describe a patient with human immunodeficiency virus type-1 (HIV) infection and alveolar echinococcosis (AE) with a focus on two messages. Despite being severely immunocompromised over years the patient exhibited a long-term asymptomatic course of AE. This is in clear contrast to reports describing accelerated courses of AE in immunocompromised patients. The patient had therapeutic mebendazole drug levels with only 1/10 of the normal drug dose. He was co-treated with protease inhibitors for his HIV infection. These drugs are known as strong inhibitors of cytochrome P450 3A4 (CYP3A4)-dependent metabolism. We speculate that benzimidazoles and protease inhibitors interfere at the CYP3A4-level. The first report of co-infection of HIV and accelerated AE was in a young girl with an extremely low CD4 cell count and an abrogated lymphoproliferative responsiveness to parasite antigen stimulation. Since the CD4 cell count in our patient remained in the range of 27-150 cells/microl, we speculate that there was a critical threshold of immunosupression for constraining AE. Initial treatment with albendazole for AE added to the current highly active antiretroviral treatment (HAART), and suppressive toxoplasmosis therapy became complicated by pancytopenia. After full recovery of the bone marrow, mebendazole was introduced with a new HAART and the previously prescribed toxoplasmosis maintenance therapy. Surprisingly, efficient mebendazole levels were achieved with an uncommonly low dose. These observations suggest that the benzimidazoles, albendazole and mebendazole, may interact with protease inhibitors, which are known for their strong inhibition of the CYP3A4.

AIDS-Related Opportunistic Infections↗

PubMed2004

Fatal subarachnoid hemorrhage after carotid stenting.

BACKGROUND AND PURPOSE: Cerebral hyperperfusion syndrome with intracerebral hemorrhage (ICH) following carotid angioplasty and stent placement (CAS) of the internal carotid artery (ICA) is well known. We report the occurrence of fatal subarachnoid hemorrhage in a patient undergoing CAS. CASE REPORT: A 77-year-old woman experiencing a left-hemispheric transient ischemic attack underwent CAS for a 95% stenosis of the left ICA. CAS was performed without acute complications. At 5 hours the patient suddenly deteriorated. Her level of consciousness changed and she developed neck stiffness. CT of the brain revealed diffuse SAH with acute hydrocephalus. CONCLUSIONS: Like ICH, SAH may develop as a severe complication after CAS. There are no reliable clinical symptoms preceding this fatal complication. However, several factors such as long-standing severe carotid stenosis with contralateral occlusion and increasing blood pressure after CAS accompanied by the extensive use of antithrombotic agents may predispose to this fatal complication.

Aged↗

PubMed2004

[Dacryocystorhinostomy - state of the art, indications, results].

BACKGROUND: In the ophthalmological literature external dacryocystorhinostomy (DCR) is considered the gold standard for the treatment of lacrimal duct stenoses. Rhinologists, on the other hand, favour the endonasal approach. MATERIALS AND METHODS: On the basis of an extensive review of the literature and our own longstanding experience we present an overview of the causes, the necessary diagnostic procedures and the surgical management of lacrimal duct stenosis. The outcomes of the two operative approaches are compared and special operative techniques and aids such as the use of laser, endoscopic dacryoplasty, silicone stenting, silicone cones with lacrimal duct stenting and the use of mitomycin C are discussed. RESULTS: The results published for endonasal DCR are slightly worse than those for the external operation. The success rates are around 90 %. Laser-assisted DCR and endoscopic dacryoplasty do not currently appear to yield better results than the conventional methods. Silicone stenting is not necessary in conventional endonasal DCR except in the case of presaccal stenosis. There are no established indications or treatment regimens for mitomycin C to date. Postoperative care after endonasal DCR should consist in the removal of fibrin, crusts and granulations and the administration of eye drops (antibiotic + cortisone) and nasal steroids. DISCUSSION: With appropriate operative technique and in experienced hands, the success rates of endonasal DCR are practically equal to those of the classical external approach. Major advantages of the endonasal approach are shorter operation times, lower complication rates and reduced patient morbidity. Neither silicone stenting nor the application of mitomycin C are routinely indicated. Laser-assisted techniques do not currently appear to improve results. Appropriate postoperative care is essential to prevent endonasal synechiae and subsequent recurrences.

Dacryocystorhinostomy↗

PubMed2003

[Fever after a tick bite: clinical manifestations and diagnosis of acute tick bite-associated infections in northeastern Switzerland].

BACKGROUND: Different tick-borne infections can cause an acute febrile illness. The study objectives were to investigate the clinical manifestations and diagnosis of infections among patients who presented with fever after a tick-bite, and to detect newly described pathogens, including Ehrlichia, Babesia and Rickettsia helvetica, in North-Eastern Switzerland. PATIENTS AND METHODS: : We studied 75 patients (41 male, 34 female, median age 38 years, among them 10 children) who had fever within 3 weeks after a tick-bite. Paired sera were tested for antibodies to Borrelia burgdorferi, tick-borne encephalitis virus, Anaplasma (Ehrlichia) phagocytophila, Babesia microti, B. divergens, and Rickettsia helvetica. In addition, microscopy and polymerase chain reaction was used to detect Ehrlichia. Clinical data were obtained at baseline and at 1 and 2 year follow-up. RESULTS: Tick-borne infections were confirmed or possible in 36 (48 %) patients: 7 (9 %) Erythema migrans, 6 (8 %) other specific manifestations of Lyme borreliosis, 6 (8 %) Lyme borreliosis presenting as non-specific febrile illness, 8 (11 %) tick-borne encephalitis, 7 (10 %) granulocytic ehrlichiosis, 1 B. microti infection in a traveler from the US and 6 (8 %) dual infections. In 8 (11 %) patients serological findings were suggesting possible acute or past R. helvetica infection. CONCLUSION: Among patients with fever after a tick-bite, Lyme borreliosis was most frequently found. There was no evidence for babesiosis among the resident population. Serologic data suggest that human granulocytic ehrlichiosis and R. helvetica infections may be endemic in Switzerland. Among 50 % of the patients no tick-borne infections could be diagnosed.

Acute Disease↗

PubMed2003

Modelling the 3-year risk of myocardial infarction among participants in the Data Collection on Adverse Events of Anti-HIV Drugs (DAD) study.

OBJECTIVES: To estimate the 3-year risk of myocardial infarction (MI) among participants in the Data Collection on Adverse Events of Anti-HIV Drugs (DAD) study. METHODS: Conventional cardiovascular risk equations were applied to baseline data from the DAD study to estimate the 3-year risk of MI. Best estimates were obtained by simply applying the risk equations, with upper and lower limits based on worst case and optimistic case scenarios. Three-year risks of AIDS or death were also estimated based on a prognostic scoring system for patients receiving antiretroviral (ARV) treatment, and on estimated AIDS rates in untreated people with HIV for those patients not on ARVs or if they were to cease ARVs. RESULTS: Analyses were based on 17 600 patients (24.3% female) recruited into the DAD study with baseline data and no previous MI. The overall 3-year risk of MI was estimated to be 0.72% (lower limit 0.35, upper limit 1.12%), corresponding to a total predicted 127 (65-197) MIs over a 3-year follow-up period. The risk was much greater for men than women (0.92% vs. 0.07%), with only three (2-8) MIs predicted in women. The 3-year risk of MI was estimated to increase from 0.30% (0.20-0.38%) in ARV naive patients to 1.07% (0.43-1.77%) in patients receiving ARVs from all three drug classes. The estimated 3-year risk of AIDS or death was in the range 6.2% to 11.1% in patients receiving ARVs if they continued treatment, and 22.5% to 29.4% if they ceased ARVs. DISCUSSION: These models suggest that although the increase in relative risk of MI as a result of ARV treatment may be as high as threefold in a worst case scenario, the absolute risk is modest with a best estimate of 3-year risk less than or equal to 1% in all groups of patients, and is outweighed by the benefits of ARV treatment in terms of reduced risk of AIDS and death in most patients. As estimates are based on models not validated for people receiving ARV drugs, all estimates should be interpreted cautiously.

Adult↗

PubMed2003

Quality of generalist vs. specialty care for people with HIV on antiretroviral treatment: a prospective cohort study.

OBJECTIVES: To describe health-care use by persons with HIV in an urban area of Switzerland (Zurich). Further, to compare the different health-care settings. DESIGN: A 1-year prospective cohort study recruiting 60 patients at general practices and 60 patients at a specialized university outpatient clinic. METHODS: Patients and their treating physicians were interviewed or answered questionnaires, respectively, at baseline, month 6 and 12. RESULTS: During the study period, five patient groups were identified among the 106 enrolled patients, of whom (i) 42% saw a general practitioner exclusively, (ii) 31% were treated at the specialized outpatient clinic, (iii) 8% were in shared care, (iv) 10% changed health-care model, and (v) 9% were lost to follow-up. Baseline demographic, psychosocial and clinical data were similar among patient groups. At study end, the proportion of patients with HIV-1 RNA < 400 copies/mL was 72%, 74%, 88%, 55% among groups (i) to (iv), respectively (ns), and 22% at month 6 among those lost to follow-up. Indicators for quality of care were similarly good among all patient groups. CONCLUSIONS: A well-working system offers high-quality healthcare to persons living with HIV, where existing teams of specialty and primary health-care professionals efficiently and effectively co-operate.

Adult↗

PubMed2003

[Structures of co-operation between an HIV-outpatient clinic and private care physicians].

OBJECTIVES OF THE STUDY: This qualitative study looks at structures of co-operation between the two major HIV-care settings in the region of Zurich (Switzerland), i.e. a HIV-specialised outpatient clinic at the University hospital and private practitioners. Hypothesizing that good co-operation between the institutions increases the quality and effectiveness of care for patients living with HIV and treated with highly active antiretroviral therapy (HAART), the structures of co-operation are investigated. METHODS: Qualitative data were collected by means of three focus-group discussions with physicians from both settings. By means of a structured interview guide, different aspects of co-operation were assessed (e. g. current status, deficits, degree of satisfaction). Contents analysis of the data revealed consensus versus dissonance pertaining to different areas of co-operation. RESULTS: Results show that co-operation has been implemented effectively on three different planes (case-related, knowledge-related, training-related) and generally has been perceived by the participants to function well. Institutions have different emphasis on care (specialists vs. generalists). They formulate different concepts of co-operation, which result in diverse degrees of satisfaction. CONCLUSIONS: On the basis of the results obtained, suggestions for improved co-operation as recommended by the participants are discussed, which could further increase the quality of HIV-related care.

Antiretroviral Therapy, Highly Active↗

PubMed2003

[Influence of age at onset, age and duration of illness on cognitive abilities in patients with refractory epilepsy].

This retrospective study was performed as part of the controversial discussion whether increasing cognitive deficits in patients with refractory epilepsy are mainly an effect of normal aging or caused by epilepsy related noxious events during the course of an intractable epilepsy. Neuropsychological data and information about the course of the disease from 146 patients with refractory epilepsy were available. There were significant correlations between the age at onset and premorbid intelligence, duration of disease and fluid intelligence and age and difference between premorbid intelligence and fluid intelligence as a measure of cognitive deterioration. Discussing these results we conclude that beneath a clear effect of normal aging on cognitive deterioration there is probably a small effect of the refractory course of the epilepsy, which might be mediated by the number of seizures. Additionally we would like to encourage early cognitive screening and rehabilitation programmes for patients with epilepsy to minimize the effect of the age of onset on the level of education or premorbid intelligence.

Adult↗

PubMed2003

Short-term temporal variation in PM2.5 mass and chemical composition during the Atlanta Supersite Experiment, 1999.

Measurements in urban Atlanta of transient aerosol events in which PM2.5 mass concentrations rapidly rise and fall over a period of 3-6 hr are reported. The data are based on new measurement techniques demonstrated at the U.S. Environmental Protection Agency (EPA) Atlanta Supersite Experiment in August 1999. These independent instruments for aerosol chemical speciation of NO3-, SO4(2-), NH4+, and organic and elemental carbon (OC and EC), reconstructed the observed hourly dry PM2.5 mass to within 20% or better. Data from the experiment indicated that transient PM2.5 events were ubiquitous in Atlanta and were typically characterized by a sudden increase of EC (soot) and OC in the early morning or SO4(2-) in the late afternoon. The frequent temporal decoupling of these events provides insights into their origins, suggesting mobile sources in metro Atlanta as the main contributor to early morning PM2.5 and more regionally located point SO2 sources for afternoon PM2.5 events. The transient events may also have health implications. New data suggest that short-term PM2.5 exposures may lead to adverse health effects. Standard integrated filter-based techniques used in PM2.5 compliance monitoring networks and in most past PM2.5 epidemiologic studies collect samples over 24-hr periods and thus are unable to capture these transient events. Moreover, health-effects studies that focus on daily PM2.5 mass alone cannot evaluate the health implications of the unique and variable chemical properties of these episodes.

Aerosols↗

PubMed2002

Magnetic resonance imaging following fat obliteration of the frontal sinus.

The paper describes the evaluation of magnetic resonance imaging (MRI) following osteoplastic flap procedure with fat obliteration. MRI scans performed in patients after surgery between 1st January 1986 and 31st December 1997 were evaluated. Outcome parameters were time-dependent changes in the distribution of adipose or connective tissue, development of necroses or oil cysts, recurrences, inflammatory complications, or mucocoeles. Eighty-six postoperative MRI scans from 51 operations were evaluated. In 19 cases between two and five MRI scans were available. Time between surgery and the last MRI scan was 24.1 months on average. We found five mucocoeles. The amount of adipose tissue depictable on the last scan was less than 20% in the majority of cases (53%) and more than 60% in only 18% of cases. Statistical tests and modelling showed a significant decrease of adipose tissue with time, with a median half-life of 15.4 months in a subgroup with at least two MRIs. MRI is at times the most valuable diagnostic tool after frontal sinus obliteration using adipose tissue. The method has some limitations with regard to detection of small (recurrences of) mucocoeles and differentiation between vital adipose tissue and fat necroses in the form of oil cysts. In difficult cases long-term MRI follow-up is necessary for definitive evaluation.

Adipose Tissue↗

PubMed2002

Dechlorination and destruction of PCDD, PCDF and PCB on selected fly ash from municipal waste incineration.

The potential of fly ash to dechlorinate and destroy PCDD, PCDF and PCB was tested under oxygen deficient conditions in the laboratory. Specifically, two types of fly ash were compared, originating either from a fluidized bed incinerator using Ca(OH)2 spray (FA1), or a stoker incinerator without Ca(OH)2 impact (FA2). Results from the present study indicate that on FA2 type fly ash, the degradation processes of OCDD, OCDF and D10CB occurred primarily via dechlorination/hydrogenation up to temperature settings of 340 degrees C. In contrast, FAI type fly ash was found to effect both dechlorination and destruction of these compounds already at temperature settings of 260 degrees C. The dechlorination velocity of PCDD and PCDF did not differ significantly. However, the first dechlorination step of OCDF in the 1,9-position occurred faster compared to the first dechlorination step of OCDD. The isomer pattern resulting from the dechlorination processes was quite similar on both FAI and FA2, indicating that differences in alkalinity or elemental composition of the two types of fly ashes do not have a significant influence on the position of dechlorination. PCDD and PCDF dechlorination of the 2,3,7,8-positions was not favoured over dechlorination of the 1,4.6,9-positions on either type of fly ash. In contrast, dechlorination of PCB occurred predominantly on the toxicological relevant 3- and 4-positions. The dechlorination/destruction processes were completed on both types of fly ash at 380 degrees C within one hour, which correlates well with results obtained from actual plant operation practices.

Air Pollution↗

PubMed2002

Effects of selected metal oxides on the dechlorination and destruction of PCDD and PCDF.

OCDD and OCDF spiked silica/graphite based model fly ash containing various copper compounds and metal oxides were thermally treated under oxygen deficient conditions. All copper compounds tested showed a considerable dechlorination/hydrogenation reaction at 260 degrees C. After 30 min at 340 degrees C, less than 1% of the spiked OCDD and OCDF was recovered as T4CDD/F to OCDD/F. Other compounds tested demonstrated a lower rate of dechlorination compared to the copper compounds. However, all other metal oxides showed a small dechlorination effect at 260 degrees C, which was considerably increased at 340 degrees C. The model fly.ash containing the different copper compounds or metal oxides showed comparable PCDD and PCDF isomer patterns after thermal treatment. However, small differences were observed among the different tested compounds. The PCDD and PCDF isomer patterns on the model fly ashes were similar to patterns found during dechlorination experiments on fly ashes from waste incineration processes. Model fly ash containing Ca(OH)2 exhibited the highest destruction potential, but a low dechlorination potential. In contrast, model fly ash containing any of the remaining compounds tested, was found to predominantly dechlorinate the spiked OCDD and OCDF.

Benzofurans↗

PubMed2002

Ritonavir plus saquinavir versus single protease inhibitor therapy in protease inhibitor-naive HIV-infected patients: the Swiss HIV Cohort Study.

OBJECTIVES: To compare the response to ritonavir (RTV) plus saquinavir (SQV) with single protease inhibitor (PI) therapies among PI-naive HIV-1 infected individuals. METHODS: Response to treatment was analysed according to the intent-to-treat principle in a prospective observational cohort study of 177 patients who between May 1995 and March 2000 started a double PI therapy with RTV and SQV (nonboosting dosages) plus at least one nucleoside reverse transcriptase inhibitor (NRTI) and 2,214 patients with a single PI therapy plus two NRTIs. We used survival analysis and Cox's proportional hazard regression methods. The primary endpoint was the time to a plasma viral load of < 400 copies/mL. Secondary endpoints were taken as a gain in the CD4 count of >100 cells/microL, and change of initial PI for any reason. RESULTS: Baseline characteristics in both treatment groups were balanced. Median follow-up in both groups was 10.4 months. Time to an HIV-1 viral load of < 400 copies/mL and an increase in the CD4 count of >100 x 10(6) cells/L was shorter for RTV plus SQV compared with single PI regimens (log rank test for each endpoint P < 0.05). The adjusted hazard ratios of RTV plus SQV compared with single PI regimens were 1.21 (95% confidence interval 0.99-1.47) for achieving an HIV-1 viral load of < 400 copies/mL, 1.12 (0.88-1.42) for an increase in the CD4 count of > 100 cells/microL, and 0.90 (0.73-1.11) for change of first PI regimen. CONCLUSIONS: Treatment with RTV plus SQV compared with single PI regimens appeared to give similar results for virological or immunological response.

Adolescent↗

PubMed2002

Ectopic parathyroid adenoma initially suspected to be a thyroid lesion.

Considering the variety of aberrant locations in which ectopic parathyroid adenomas may be found, these neoplasms can be difficult to identify and treat surgically. The results of radiographic and cytologic studies may lead to confusion of these neoplasms with lesions of thyroid origin. We present a case of an ectopic parathyroid adenoma for which misleading localization prompted cytologic misdiagnosis and intraoperative suspicion of thyroid carcinoma.

Adenoma↗

PubMed2002

AIDA--experiences in compensating the mutual weaknesses of knowledge-based and object-oriented development in a complex dental planning domain.

OBJECTIVES: Dentistry is a discipline with two properties that pose a serious challenge to knowledge based decision support: (1) It has to integrate six subdisciplines ranging from conservative measures to invasive disciplines, such as implantology; (2) A plan may have to cover a complex treatment often lasting one year or more. It is the aim of the AIDA-project to set up a planning strategy that is suited to incorporate all dental peculiarities in one methodology. METHODS: Generic tasks, that can be assigned to individual persons involved in dental treatment, have been designed with the help of KADS. They have been integrated into a planning super-structure for the planning of all dental solution alternatives, that can principally be applied on the basis of the given patient status. RESULTS: Besides an evaluation of the implemented planning system itself, it has been evaluated how well the development is supported by (1) knowledge-engineering methods and (2) object-oriented methods. CONCLUSION: Common knowledge-based tools are not powerful enough for the planning of complex dental constructions. Therefore, a solution combining object-oriented and knowledge-based methods is proposed.

Artificial Intelligence↗

PubMed2001

Historical PCDD inputs and their source implications from dated sediment cores in Queensland (Australia).

Recent investigations have demonstrated the presence of an unidentified source of polychlorinated dibenzo-p-dioxins (PCDDs) in the coastal zone of Queensland (Australia). The present study provides new information on the possible PCDD sources and their temporal input to this environment. Two estuarine sediment cores were collected in northern Queensland for which radiochemical chronologies were established. Core sections from different depositional ages, up to three centuries, have been analyzed for 2,3,7,8-substituted PCDDs and polychlorinated dibenzofurans (PCDFs). Variations of PCDD concentrations in the sediment cores over several centuries of depositional history were relatively small, and elevated PCDD levels were still present in sediment slices from the early 17th century. PCDD/F isomer patterns and congener profiles in sediments deposited during the last 350 years were almost identical and correlated well to the characteristic profiles observed in surface sediments and soils from the entire Queensland coastline. Profiles were dominated by higher chlorinated PCDDs, in particular octachlorodibenzodioxin (OCDD), whereas PCDF concentrations were below or near the limit of detection. These results indicate the presence of a PCDD source prior to industrialization and production of commercial organochlorine products. Further, the present study demonstrates that PCDD input patterns have been similar along an extensive but localized area over at least several centuries, contributing relatively high concentrations of PCDDs to the coastal system of Queensland.

Environmental Monitoring↗

PubMed2001

HIV viral load response to antiretroviral therapy according to the baseline CD4 cell count and viral load.

CONTEXT: It is unclear whether delay in initiation of antiretroviral therapy (ART) may lead to a poorer viral load response for patients with human immunodeficiency virus (HIV). OBJECTIVE: To characterize the relationship of viral load response to ART with baseline CD4 cell count and baseline viral load. DESIGN: Inception cohort of 3430 therapy-naive patients with HIV, of whom 3226 patients had at least 1 viral load count after the start of ART. SETTING: Three cohort studies of patients cared for in HIV clinics in Europe between 1996 and 2000. PATIENTS: All patients initiating ART consisting of at least 3 drugs initiated in or after 1996 and for whom CD4 cell count and viral load were available in the prior 6 months (at most). MAIN OUTCOME MEASURES: Viral load decrease to below 500 copies/mL; viral load rebound to above 500 copies/mL (2 consecutive values). RESULTS: Of 3226 patients during the median follow-up of 119 weeks, 2741 (85%) experienced viral suppression to less than 500 copies/mL by 32 weeks. Relative hazards (RHs) of achieving this were 1.08 (95% confidence interval [CI], 0.98-1.21) and 0.94 (95% CI, 0.84-1.04) for baseline CD4 cell counts between 200 and 349 x 10(6)/L and baseline CD4 cell counts lower than 200 x 10(6)/L, respectively, compared with baseline CD4 cell counts of 350 x 10(6)/L or higher, after adjustment for several factors including baseline viral load. For baseline viral load, the RHs were 0.95 (95% CI, 0.84-1.07) and 0.65 (95% CI, 0.58-0.74), for 10 000 to 99 999 and 100 000 copies/mL or greater, respectively, compared with less than 10 000 copies/mL, but the probability of viral load lower than 500 copies/mL at week 32 was similar in all 3 groups. Subsequent rebound above 500 copies/mL was no more likely with a lower baseline CD4 cell count or higher viral load. CONCLUSION: In this study, lower CD4 cell counts and higher viral loads at baseline were not associated with poorer virological outcome of ART. Those with baseline viral loads of greater than 100 000 copies/mL had a slower rate of achieving viral suppression.

Adult↗