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Biomedical subjects

P Schäfer

Publications and source records attributed to P Schäfer.

At least 19 recordsLinked to original sources
PubMed2006

[Clinical use of a voice prosthesis with a flap valve containing silver oxide (Blom-Singer Advantage), biofilm formation, in-situ lifetime and indication].

BACKGROUND: Fungal growth and the resulting leakage through an indwelling voice prosthesis remains the most frequent reason of prosthesis failure and renewal. In some patients leakage caused by fungal growth occurs in very short intervals (below 12 weeks in-situ lifetime) and causes frequent treatments and high costs. METHODS: The Blom-Singer(R) Advantage voice prosthesis is a new prosthesis type with a modified flange design, a flap valve containing 7 % silver oxide in the silicon matrix and is expected to be resistant against biofilm formation and fungal growth. PATIENTS: In a clinical trial we used the Blom-Singer(R) Advantage prosthesis in 33 patients with short in-situ lifetimes of their voice prosthesis and analysed the effects on in-situ lifetime and complications statistically. RESULTS: The clinical use of the Blom-Singer(R) Advantage prosthesis was similar to other types of indwelling voice prosthesis (Provox(R) II, Blom-Singer Indwelling(R)) and did not cause any special problems. Prosthesis specific side effects (i. e. allergy against silver oxide) did not occur. Statistical analysis of the aquired data showed an interindividually changing, but significantly longer in-situ lifetime for the Blom-Singer(R) Advantage prosthesis. The mean device lifetime increased from 36 days (median 36 days) to a mean lifetime of 110 days (median 87 days) with the use of the Blom-Singer(R) Advantage prosthesis. CONCLUSIONS: Using a voice prosthesis with a valve containing silver oxide can normalize and even increase the in-situ lifetime in patients with frequent changing procedures caused by fungal growth on the valve. Therefore we recommend the use of this type of voice prosthesis for those patients as reduction of costs and effort results.

Aged↗
PubMed2006

[The custom-fit voice prosthesis, for treatment of periprothetic leakage after tracheoesophageal voice restoration].

BACKGROUND: Leakage around an indwelling voice prosthesis is detected during 13% up to 27% of all replacement procedures of voice prosthesis and causes serious complications in further voice restoration of the laryngectomee. Lots of therapeutic options to stop periprothetic leakage have been described (Injection of Bioplastique, autologous fat or collagen, suture techniques, spacer therapy) without convincing success rates. METHODS: Custom-fit voice prostheses are ordinary indwelling voice prostheses (Blom-Singer low pressure Indwelling 20 fr) with enlarged flanges and reduced shaft length that are individually sized for the shunt of the laryngectomee. Especially enlarging the esophageal flange provides a tight sealing of leakage around the prosthesis. PATIENTS: In a one year lasting clinical trial 692 voice prostheses were changed. In 77 cases periprothetic leakage was detected and fistulas were fitted with individually sized voice prostheses. RESULTS: In 76 cases total control of leakage was achieved without any specific complications taking place. Moreover two types of leaking tracheoesophageal fistulas were distinguished, a dilated-atrophic and an infected-necrotic type. 57% of the fistulas were dilated-atrophic type and 43% of the fistulas were classified infected-necrotic type. Infected-necrotic fistulas needed enlarged flanges tracheal an esophageal for tight sealing in 91% of the cases whereas dilated-atrophic fistulas needed double flanges only in 45%. 70% of infected-necrotic type fistulas needed only one singular history of a custom-fit prosthesis and could be changed back to ordinary indwelling prostheses after healing had taken place. CONCLUSIONS: As the insertion of a modified prosthesis is only slightly more effort than an ordinary voice prosthesis insertion, the success rate is high und complications are rare we recommend the custom-fit voice prosthesis for treatment of periprothetic leakage.

Aged↗
PubMed2006

Controlling planar and vertical ordering in three-dimensional (In,Ga)As quantum dot lattices by GaAs surface orientation.

Anisotropic surface diffusion and strain are used to explain the formation of three-dimensional (In,Ga)As quantum dot lattices. The diffusion characteristics of the surface, coupled with the elastic anisotropy of the matrix, provides an excellent opportunity to influence the dot positions. In particular, quantum dots that are laterally organized into long chains or chessboard two-dimensional arrays vertically organized with strict vertical ordering or vertical ordering that is inclined to the sample surface normal are accurately predicted and observed.

Journal Article↗
PubMed2006

Increased risk of acute myeloid leukaemia after treatment for breast cancer.

This study evaluates the risk of acute myeloid leukaemia (AML) in patients treated for breast cancer. We included all 6360 breast cancer patients that were recorded at the Geneva Cancer Registry between 1970 and 1999. Patients were followed for AML occurrence until December 2000. We calculated standardized incidence ratios of AML and identified factors modifying the risk of AML by multivariate Cox analysis. Twelve (0.2%) patients developed AML. In general, patients treated for breast cancer had a 3.5-fold (95% confidence interval (CI): 1.8-6.0) increased risk of developing AML compared with the general population. In particular, patients who were older than 70 years at breast cancer diagnosis and those treated with radiotherapy (with or without chemotherapy) had a significantly increased risk of developing AML. This population-based study confirms that radiotherapy increases the risk of AML. Due to the relatively low number of women treated with chemotherapy without radiotherapy and due to the infrequency of the disease, the question of whether chemotherapy alone increases this risk of AML cannot yet be answered.

Aged↗
PubMed2003

[Initial examination for school attendance in Mannheim: language development at initial school entry level].

INTRODUCTION: In autumn 2001 the initial examination for school attendance in Mannheim has been fundamentally reorganised. The individual examination elements had been widely standardized, the results can be evaluated by regions and a diagnosis for the early detection of legasthenia has been developed. METHODS: The testing involved repeating sentences, numbers and artificial words. This has been developed by the Pedagogical University Heidelberg. In pre-examinations in Heidelberg the results relate significantly to the subsequent results in reading and writing. PROBANDS: A total of 2,744 children (46.1% girls, 53.9% boys) aged of 5 to 7 years was seen. 71.5% of the children were German nationality. Most non-German nationalities were Turkish (15.4%) and Italian (3.6%) children. Besides the nationality the mother tongue has been also recorded. More than 96% of the children had been attending a kindergarten. For judgement of the social strata the frequency of social welfare receivers has been recorded. RESULTS: The testing results are significantly influenced by the native language and the social strata of the children. The results of children with German as native language are above those of non-Germans. Within the migrant children there are significant differences between the several nationalities. Children from a lower social strata achieved lower results. A positive effect to the language development is attributed to the attendance of a kindergarten. CONCLUSION: These results are the basis for language- and general health supporting projects in Mannheim. For the examination for school attendance in the current year the diagnostic for language development has been extended by some more aspects.

Child↗
PubMed2003

Long-term improvements in cognitive performance through computer-assisted cognitive training: a pilot study in a residential home for older people.

The aim of the present pilot study was to investigate the effects of computer-assisted cognitive training on aging-associated memory deficits, information processing speed, learning, and interference tendency in older people. Residents of a home for older people (15 women, four men; mean age 83.5; range 75-91) participated in a 14-week computer-assisted cognitive training program. The Niirnberg Aging Inventory and the California Verbal Learning Test were administered prior to the program, immediately after the program and after a period of five months to assess the effectiveness of the cognitive training. After the cognitive training program there were significant improvements in primary working memory and also secondary working memory (for verbal and visual stimuli), on parameters of information processing speed, learning and interference tendency. Improvements in the last two cognitive parameters were maintained five months after completion of the training program. The present study indicates that computerized cognitive training programs can be used in older people to achieve long-term improvements in some important aspects of fluid intelligence. It is suggested that computers could be employed more extensively to prevent and treat cognitive deficits in older people.

Aged↗
PubMed2002

Prevalence of SENV-H viraemia among healthy subjects and individuals at risk for parenterally transmitted diseases in Germany.

The prevalence of a newly described DNA virus (SENV-H) was examined in a population of 599 individuals by polymerase chain reaction (PCR). All individuals were assigned to a nonrisk or a risk group depending on the presence of historical or serological factors indicating an increased risk for parenterally transmitted diseases. In a group of 226 healthy blood donors, 38 (16.8%) were found to be SENV-H viraemic. The highest prevalence of SENV-H viraemia was observed among patients infected by HIV (28 of 63; 44.4%). Contrarily, of 78 individuals on maintenance haemodialysis, only 10 (12.8%) were found positive in the SENV-H PCR. Our results demonstrate that SENV-H viraemia is widespread in the general population. Therefore, it seems to be questionable if parenteral transmission is the main route for spreading SENV-H. The hepatitis-inducing capacity of SENV-H is unclear. However, taking our clinical and epidemiological data into account it seems unlikely that this virus is responsible for hepatitis.

Adolescent↗
PubMed2002

Management of women with ductal carcinoma in situ of the breast: a population-based study.

BACKGROUND: Increasing incidence of ductal carcinoma in situ (DCIS) confronts patients and clinicians with optimal treatment decisions. This multidisciplinary study investigates therapeutic modalities of DCIS in daily practice and provides recommendations on how to increase quality of care. PATIENTS AND METHODS: All women (n = 116) with unilateral DCIS recorded in the Geneva Cancer Registry from 1995 to 1999 were considered. Information concerned patient and tumor characteristics, treatment and outcome. Factors linked to therapy were determined using a case-control approach. Cases were women with treatment of interest and controls other women on the study. RESULTS: Most DCIS cases (62%) were discovered by mammography screening. Ninety (78%) women had breast-conserving surgery (BCS), 18 (16%) mastectomy and seven (6%) bilateral mastectomy. Eight (7%) patients had tumor-positive margins, 18 (16%) lymph node dissection and two (1.7%) chemotherapy. Twenty-five per cent of women with BCS had no radiotherapy, three had radiotherapy after mastectomy. Less than 50% underwent breast reconstruction after mastectomy. Method of discovery, multifocality, tumor localization, size and differentiation were linked to the use of BCS or lymph node dissection. CONCLUSIONS: Because of important disparities in DCIS management, recommendations are made to increase quality of care, in particular to prevent axillary dissection or bilateral mastectomy and to increase the use of radiotherapy after BCS.

Adult↗
PubMed2001

Antibodies to chlamydial lipopolysaccharides in unstable angina pectoris.

Patients with coronary artery disease frequently have elevated antibody titers against Chlamydia pneumoniae, but whether antichlamydial antibody titers are correlated with prognosis in unstable angina remains unclear. We therefore investigated the sera of 1,096 patients with unstable angina regarding immunoglobulin (Ig) IgG, IgA, and IgM antibody titers against chlamydial lipopolysaccharides (LPS) and the concentrations of C-reactive protein (CRP) and troponin T (TnT). Anti-LPS IgG titers were increased in 45% of patients at enrollment and in 48% of patients at discharge (p <0.0001). Anti-LPS IgA titers were increased in 27% of patients at enrollment and in 33% of patients at discharge (p <0.0001). Patients who subsequently died had significantly lower IgM titers at enrollment than patients without events (p = 0.016). IgG, IgA, or IgM titers did not correlate with concentrations of CRP or TnT. In this large-scale study of patients with unstable angina, we frequently found elevated antichlamydial antibody titers. Patients with low IgM anti-LPS titers were at risk for subsequent death. However, there was no correlation between antichlamydial antibody titers and CRP or TnT.

Aged↗
PubMed2001

Strategies for reliable diagnosis of hepatitis C infection: the need for a serological confirmatory assay.

The aim of the study was to examine whether the diagnosis of Hepatitis C (HCV) infection can be obtained reliably without using an immunoblot-based confirmation assay. 1,708 EIA-reactive serum samples were examined retrospectively for (i) optical density value in the screening assay, (ii) reactivity in an immunoblot assay, and (iii) result by RT PCR. In 1,394 (81.0%) samples positive results were obtained by both the HCV EIA and the confirmation assay. OD-values > or = 2.2 were observed in 1026 of these samples, but covered the range from 0.4 to 2.1 in the other 368 samples. The combination of HCV EIA reactivity and indeterminate immunoblot assay was observed in 134 (7.8%) serum samples. HCV RNA was detected in 58 cases by PCR. The OD-values of these 58 samples ranged from 0.4 to >2.2. Especially reactivity against the core recombinant protein was indicative of PCR positivity. The reactivity by the HCV EIA could not be confirmed by immunoblot assay or PCR in 180 (10.5%) sera. These false reactive sera showed OD values by EIA from 0.3 to 2.1. It is concluded that no threshold values can be defined which would allow differentiation between positive, indeterminate, and false reactive result by HCV EIA without producing an unacceptably high number of false negative diagnoses. Not using immunoblot-based confirmation would result in many additional PCR examinations. Therefore, confirmation of reactive HCV EIA results by a serological confirmatory assay must remain an essential part of the diagnostic procedure.

DNA, Viral↗
PubMed2001

Correlation of hepatitis B virus load with loss of e antigen and emerging drug-resistant variants during lamivudine therapy.

It remains unclear whether sequential assessment of hepatitis B virus (HBV) load during lamivudine therapy can predict the loss of hepatitis B e antigen or emergence of drug-resistant variants. Therefore, a longitudinal study was carried out in 28 consecutive patients with chronic hepatitis B who started lamivudine therapy for a median of 12 months (range, 6-31). HBV DNA copy numbers were determined at 3-month intervals. From month 6 onward, HBV viral load below the detection limit of the PCR was predictive of the loss of envelope antigen (P = 0.043). Continuously detectable HBV DNA during the first 12 months of treatment indicated emergence of drug-resistant variants (P = 0.034). These data suggest that the goal of lamivudine therapy should be complete suppression of serum HBV DNA.

Administration, Oral↗
PubMed2001

Application of HIV-1 genotypic-resistance testing prevents the evolution of further resistance mutations in heavily pretreated patients.

BACKGROUND: Resistance-associated mutations in HIV-1 evolve even under highly active antiretroviral therapy. OBJECTIVE: To evaluate the clinical efficacy of genotypic-resistance testing (GRT), to estimate the potential of a given antiretroviral therapy for prevention of further resistance mutations. STUDY DESIGN: Ten patients were treated prospectively with drugs, according to the results of a GRT. Five patients were allocated to group I in which antiretroviral therapy could be switched to an effective regimen (consisting of at least three sensitive drugs, from at least two different classes of antiretroviral substances). Five patients (group II) had no option for effective therapy, and continued to be treated non-effectively (at least one applicated substance class only intermediately sensitive, or resistant). GRT and quantitative viral cultures were performed longitudinally for 8 months. Also, plasma HIV-1 RNA, total CD4+ cells, and rates of productively infected CD4+ cells were determined. RESULTS: All the patients in group I showed a significant decrease of HIV-RNA of >1 log/ml (mean, -1.35 log/ml, P=0.025). The mean increase of CD4+ cells was 46 (not significant). The rate of productively infected CD4+ cells decreased significantly (mean, -16 productively infected CD4+ cells per 10(6) total CD4+ cells, P=0.04). In this group no further resistance mutations were detected after 8 months. In group II, none of the patients showed a significant decrease of HIV-1 RNA (mean, +0.05 log/ml), total CD4+ cells decreased (mean, -35, not significant), the rate of productively infected CD4+ cells increased significantly (mean, +124 productively infected CD4+ cells per 10(6) total CD4+ cells, P=0.04), and 4 of 5 patients had additional mutations in the RT gene conferring multi-drug resistance within 8 months (P=0.048). CONCLUSIONS: GRT is predictive of the efficacy of a therapeutic regimen, in particular regarding evolution of further resistance mutations.

Adult↗
PubMed2001

Comparison of three HCV genotyping assays: a serological method as a reliable and inexpensive alternative to PCR based assays.

BACKGROUND: Determination of hepatitis C virus (HCV) genotypes and subtypes is of rising clinical importance. In times where also an increasing need for cost effectiveness can be observed, the demand for fast and easy performable assays grows. OBJECTIVES: To evaluate and compare different genotyping methods regarding their reliability, practicability, and expense in the daily routine. METHODS: Sera of 39 patients infected with different HCV subtypes were examined by a serological genotyping assay (NS-4 IBA), by the widely used INNO-LiPA HCV II, and by a nucleotide sequencing method. RESULTS: The tests performed equally well in terms of HCV subtyping and no different results were obtained. However, the serotyping assay provided the results in less than half the time needed by the other two assays. Significant differences were also observed regarding the 'hands on' times and the costs. The technical equipment which was necessary to perform the assays is significantly reduced using the serological assay. CONCLUSION: Our study demonstrates that the serological test offers the opportunity to determine HCV genotypes and subtypes reliably, fast, easy, and cost effective.

Genotype↗
PubMed2001

Patient cytomegalovirus seropositivity with or without reactivation is the most important prognostic factor for survival and treatment-related mortality in stem cell transplantation from unrelated donors using pretransplant in vivo T-cell depletion with anti-thymocyte globulin.

We evaluated the cytomegalovirus (CMV) serostatus as a risk factor for survival and treatment-related mortality (TRM) in 125 patients allografted from an unrelated donor between 1994 and 1999. All patients received pretransplant in vivo T-cell depletion using rabbit anti-thymocyte globulin (ATG). Only one patient had primary graft failure and severe grade III/IV graft-versus-host disease occurred in 14% of the patients. The overall survival (OS) at 3 years was 70% for CMV-negative patients (n = 76) and 29% in the seropositive cohort (n = 49) (P > 0.001). In multivariate analyses, CMV seropositivity remained an independent negative prognostic factor for OS (RR: 2.1; CI: 1.2-3.8; P = 0.014), apart from age > 20 years (RR: 2.74; CI: 1.2-3.8; P = 0.004) and late leucocyte engraftment (RR: 2.4; CI: 1.2-4.9; P = 0.015). The TRM for all patients was 27%. Despite monitoring for CMV antigenaemia and preemptive therapy with ganciclovir when reactivation occurred, seropositive patients had a three times higher risk of fatal treatment-related complications than seronegative patients. In multivariate analyses, CMV seropositivity remained the strongest independent negative factor for TRM (RR: 5.3; CI: 1.9-14.6; P = 0.002), followed by age > 20 years (RR: 4.8; CI: 1.3-18.1; P = 0.02) and delayed leucocyte engraftment (RR: 3.6; CI: 1.2-11; P = 0.02). The TRM was identical in seropositive patients with (n = 27) or without (n = 22) CMV reactivation (44% versus 50%). We conclude that CMV seropositivity, despite preemptive ganciclovir therapy and even without reactivation, is a major negative prognostic factor for survival as well as for TRM in unrelated stem cell transplantation using pretransplant in vivo T-cell depletion with ATG.

Acute Disease↗
PubMed2001

[Voice restoration with voice prosthesis after total laryngectomy. Assessment of survival time of 378 Provox-1, Provox-2 and Blom-Singer voice prosthesis].

UNLABELLED: Voice Restoration with Voice Prosthesis after Total Laryngectomy. Assessment of Survival Time of 378 Provox-1, Provox-2 and Blom-Singer Voice Prosthesis. BACKGROUND: Indwelling voice prosthesis are used in Trier for voice restoration after total laryngectomy since 1991. OBJECTIVE AND METHOD: To assess the voice prosthesis survival times the patients of the years 1993-1999 are assessed retrospectively. PARTICIPANTS: 58 patients provided with indwelling voice prosthesis were seen regularly at follow-up. 378 prosthesis were changed. Provox 1, Provox 2 and Blom-Singer-Prostheses were used. RESULTS: The average survival lifetime of the prosthesis was 224 days for Provox-1, 96 days for Provox-2 and 107 days for Blom-Singer respectively. There is no significant difference found between Provox-2 and Blom-Singer Prosthesis. The survival times of the Provox-1 Prosthesis is significant longer. CONCLUSION: Using indwelling voice prosthesis for voice restoration after total laryngectomy an average survival time of the prosthesis of three months can be expected. There are relevant individual differences. Provox-1 Prosthesis have a significantly longer survival time, but as they are more difficult to handle they are not suitable for routine use. The indication for the choice between Blom-Singer or Provox-2 Prosthesis should be influenced by the surgeons' experience.

Adult↗
PubMed2001

Early rehabilitation of head-neck edema after curative surgery for orofacial tumors.

OBJECTIVE: To evaluate a rehabilitative program for postoperative head-neck edema. DESIGN: Eleven patients completed the study. A series of ten manual lymphatic drainage were initiated and completed early after surgery. On discharge from the hospital, the patients wore "made-to-measure" or customized compression garments for the next several weeks. Tape measurements and sonographic evaluation of the soft-tissue width were used to quantify the extent of the swelling. RESULTS: After 6 wk of therapy, the patients exhibited a statistically significant (P < 0.05; Wilcoxon's test) remission; the remission continued in eight patients who were measured at 12+/-3 wk. CONCLUSIONS: This initial trial demonstrates that sequential therapy of manual lymphatic drainage and compression garments can significantly reduce early postoperative edema after curative surgery for orofacial tumors. The outcome can be quantified by comparing the course of distances between the defined anatomic marks and by sonographic evaluation of soft-tissue width. This pilot study encourages that more controlled, randomized studies, with larger numbers of patients, be conducted to verify these results.

Activities of Daily Living↗
PubMed2001

Viral load in breast milk correlates with transmission of human cytomegalovirus to preterm neonates, but lactoferrin concentrations do not.

In vitro, lactoferrin (LF) strongly inhibits human cytomegalovirus (HCMV), which led us to hypothesize that in vivo HCMV might also be inhibited in secretions with high LF concentrations. In breast milk, high viral loads observed as high viral DNA titers tended to coincide with higher LF levels. However, the LF levels did not correlate to virus transmission to preterm infants. The viral load in the transmitting group was highest compared to the nontransmitting group. We conclude that viral load in breast milk is an important factor for transmission of the virus.

Breast Feeding↗