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R Kaiser

Publications and source records attributed to R Kaiser.

At least 37 records · Page 2Linked to original sources
PubMed2004

Flavor decomposition of the sea-quark helicity distributions in the nucleon from semiinclusive deep inelastic scattering.

Double-spin asymmetries of semiinclusive cross sections for the production of identified pions and kaons have been measured in deep inelastic scattering of polarized positrons on a polarized deuterium target. Five helicity distributions including those for three sea quark flavors were extracted from these data together with reanalyzed previous data for identified pions from a hydrogen target. These distributions are consistent with zero for all three sea flavors. A recently predicted flavor asymmetry in the polarization of the light quark sea appears to be disfavored by the data.

Journal Article↗
PubMed2004

[Clinical courses of acute and chronic neuroborreliosis following treatment with ceftriaxone].

Between 1990 and 2000, a total of 101 patients with acute (n=86) or chronic (n=15) neuroborreliosis (proven by clinical data, pleocytosis in the CSF, and elevated Borrelia burgdorferi-specific antibody indices) were treated with 2 g of ceftriaxone per day for either 2 or 3 weeks. The patients were reexamined clinically and serologically after 3, 6, and 12 months. Six (12) months after the antibiotic treatment, about 93% (95%) of the patients with acute neuroborreliosis and 20% (66%) of the patients with chronic neuroborreliosis were cured. One year after treatment, four patients with acute neuroborreliosis still suffered from facial palsy and five with chronic neuroborreliosis still had moderate spastic ataxic gait disturbance. The prognosis of facial palsy in neuroborreliosis is quite similar to that in idiopathic facial palsy, while that in chronic neuroborreliosis largely depends on the time elapsed before diagnosis.

Acute Disease↗
PubMed2004

Safety, efficacy and development of resistance under the new protease inhibitor lopinavir/ritonavir: 48-week results.

BACKGROUND: Within this open-label, uncontrolled prospective trial we evaluated safety, efficacy and development of genotypic resistance under the new protease inhibitor lopinavir/ritonavir (LPV/r) in antiretroviral (ARV) HIV patients. PATIENTS AND METHODS: 58 patients with virological failure under their current ARV therapy were started on a LPV/r containing regimen. Median baseline HIV RNA and CD4 count were 4.6 log(10) cps/ml (range 2.1-6.4) and 128 x 10(6)/l (0-767), respectively. CD4 count, HIV RNA and metabolic parameters were assessed at weeks 0, 4, 8, 12, 16, 24, 32, 40, 48. Genotypic resistance testing was performed at baseline and again at weeks 12, 24 and 48 in the event of virological failure. RESULTS: Until week 48, viral load (VL) decreased by a median of 1.9 log(10) cps/ml (-0.8-3.8). A VL below 80 cps/ml was found in 20/58 patients (34.5%) at week 48. In parallel, CD4 cells increased to a median of 332 x 10(6)/l (8-905). Nine patients discontinued study treatment. At 48 weeks, median triglyceride and cholesterol levels increased significantly. While the median number of overall protease mutations at baseline was four in all patients, it was six in patients virologically failing on LPV/r. The average number of mutations increased significantly to eight at week 48. Several mutations were detected considerably more often in the event of failure than in response to treatment, e. g. at amino acid positions 10, 24, 54, 71, 82, 84. CONCLUSION: LPV/r is effective in heavily pretreated patients. Discontinuation due to adverse events is infrequent. No individual mutation can be associated with failure on LPV/r. However, a greater number of protease mutations at baseline is associated with poorer treatment outcome and several mutations seem to be related to treatment failure.

Adult↗
PubMed2004

HLA-DQ6 and ingestion of contaminated water: possible gene-environment interaction in an outbreak of Leptospirosis.

Leptospirosis is a zoonosis that can cause severe multisystem disease. While host gene-environment interactions likely modify infectious disease susceptibility, including for leptopsirosis, this has not been documented. In a 1998 leptospirosis outbreak investigation among triathletes in a lake swim, swallowing lake-water was a disease risk-factor. We used genomic DNA from 85 anonymized blood-sample remainders from that investigation to examine the association of laboratory-confirmed leptospirosis with gene polymorphisms (TNF-alpha alleles and serologically defined genotypes for HLA-DRB1 and HLA-DQB1). HLA-DQ6-positive triathletes had increased risk of laboratory-confirmed leptospirosis (OR=2.8, P=0.04) compared to DQ6-negatives. DQ6-positive triathletes swallowing lake-water had greatest risk (OR 8.46, P< or =0.001). This first report of a genetic risk-factor affecting susceptibility to leptospirosis is also the first documented gene-environment interaction (DQ6 and swallowed water) affecting infectious disease susceptibility. Based on these preliminary findings, we hypothesize a role for superantigens in leptospirosis and underscore the importance of outbreak investigations for understanding infectious disease gene-environment interactions.

Adolescent↗
PubMed2004

The effect of diverticular disease on the colonic J pouch.

OBJECTIVE: The aim of this study was to assess the impact of the diverticular disease (DD) on function and on postoperative complications of the colonic J-pouch (CJP) with pouch-anal anastomosis. METHODS: Patients who underwent a CJP between December 1990 and August 2001, were retrospectively reviewed. The presence of DD in the CJP was assessed on pouchogram prior to ileostomy closure. A questionnaire designed to evaluate the degree of continence (total incontinence score (IS): 0 = worst, 20 = best) and pouch evacuation (total evacuation score (ES): 0 = worst, 28 = best) was used for comparison between patients with DD and those without DD (NDD). RESULTS: Sixty-six patients (47 males; 19 females) with a median age of 68 years (range 28-87 years) were included. The median follow-up period was 22 months (range 2-106 months). Twenty-four patients comprised the DD group and 42 were in the NDD group. The two groups were comparable for age, gender and time from ileostomy closure; all patients with postoperative chemoradiation therapy were in the NDD group. The total ES and IS total did not significantly differ between the two groups with a P-value of 0.11 and 0.09 respectively. Furthermore, there was no significant difference in the total incidence of pouch complications between the two groups (3 strictures, 1 leak, 1 fistula in the NDD group vs. 1 pelvic sepsis in the DD group; P = 0.4). CONCLUSIONS: The presence of DD in a CJP does not seem to impact pouch function or the postoperative complication rate.

Aged↗
PubMed2003

Slow diffusion of light in a cold atomic cloud.

We study the diffusive propagation of multiply scattered light in an optically thick cloud of cold rubidium atoms illuminated by a quasiresonant laser beam. In the vicinity of a sharp atomic resonance, the energy transport velocity of the scattered light is almost 5 orders of magnitude smaller than the vacuum speed of light, reducing strongly the diffusion constant. We verify the theoretical prediction of a frequency-independent transport time around the resonance. We also observe the effect of the residual velocity of the atoms at long times.

Journal Article↗
PubMed2003

L -dopa-induced adverse effects in PD and dopamine transporter gene polymorphism.

OBJECTIVE: To assess whether polymorphisms in the dopamine receptor genes and in the dopamine transporter gene (DAT ) are predictors of adverse effects of L -dopa. METHODS: A retrospective noninterventional study with 183 patients with PD was conducted. Nine polymorphisms of the dopamine D2 receptor (DRD2 ), two of the dopamine D3 receptor (DRD3 ), three of the dopamine D4 receptor (DRD4 ), and one variable number of tandem repeats (VNTR) of the DAT were studied. The entire coding and promoter regions of the DRD2 gene of 48 patients with early and severe appearance of adverse effects from L -dopa treatment and of eight never-afflicted patients were sequenced. RESULTS: The polymorphisms of DRD2, DRD3, and DRD4 were not associated with the risk to develop adverse effects of L -dopa. However, patients with psychosis or dyskinesia carried the nine copy allele 40-bp VNTR of the DAT more frequently than nonafflicted patients (60.0 vs 36.8%, p = 0.008; and 54.7 vs 32.9%, p = 0.006). Sequencing of the DRD2 gene revealed no new mutation, with the exception of one silent mutation in exon 6. CONCLUSIONS: Genetic variations of the DRD2, DRD3, and DRD4 do not influence the occurrence of L -dopa-induced adverse effects. However, the nine copy allele 40-bp VNTR of the DAT is a predictor for the occurrence of psychosis or dyskinesia in L -dopa-treated patients.

Aged↗
PubMed2003

[HIV resistance. More the rule than an exception].

Resistance-associated mutations of the HIV genome are one major reason for failure of highly, active antiretroviral therapy. The accumulation of resistance is demonstrated by data from the HCUS-study, where resistant virus strains were isolated in about 50%. More than 60% of the patients showed therapy failure in this survey, and resistance was found in almost 80% of these. Mutations in the HIV genome were also described in treatment-naive patients. In the German Seroconverter Study the rate of resistance was 12%, in a multicenter study in Nordrhein-Westfalen resistant isolates were found in 14% of chronically infected cases. The wide distribution of HIV resistance in treated and untreated patients is an important problem in the management of HIV-infection. It requires a rational application of resistance testing. International studies are under way to further characterize the relevance of the phenomenon of HIV resistance.

Acquired Immunodeficiency Syndrome↗
PubMed2003

Evidence for quark-hadron duality in the proton spin asymmetry A1.

Spin-dependent lepton-nucleon scattering data have been used to investigate the validity of the concept of quark-hadron duality for the spin asymmetry A1. Longitudinally polarized positrons were scattered off a longitudinally polarized hydrogen target for values of Q2 between 1.2 and 12 GeV2 and values of W2 between 1 and 4 GeV2. The average double-spin asymmetry in the nucleon resonance region is found to agree with that measured in deep-inelastic scattering at the same values of the Bjorken scaling variable x. This finding implies that the description of A1 in terms of quark degrees of freedom is valid also in the nucleon resonance region for values of Q2 above 1.6 GeV2.

Journal Article↗
PubMed2003

Q2 dependence of nuclear transparency for exclusive rho0 production.

Exclusive coherent and incoherent electroproduction of the rho(0) meson from 1H and 14N targets has been studied at the HERMES experiment as a function of coherence length (l(c)), corresponding to the lifetime of hadronic fluctuations of the virtual photon, and squared four-momentum of the virtual photon (-Q2). The ratio of 14N to 1H cross sections per nucleon, called nuclear transparency, was found to increase (decrease) with increasing l(c) for coherent (incoherent) rho(0) electroproduction. For fixed l(c), a rise of nuclear transparency with Q2 is observed for both coherent and incoherent rho(0) production, which is in agreement with theoretical calculations of color transparency.

Journal Article↗
PubMed2003

Selective modulation of endogenous nitric oxide formation in ischemia/reperfusion injury in isolated rat hearts--effects on regional myocardial flow and enzyme release.

The role of nitric oxide (NO) in ischemia/reperfusion injury is controversial. We tested the role of inducible NOS (iNOS) in the ischemia/reperfusion injury in isolated rat hearts using the selective iNOS inhibitor S-methylisothiourea sulfate (SMT) and the non-selective NOS inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME). After 15 min of stabilization in Langendorff mode, hearts were perfused either with normal Krebs-Henseleit buffer, buffer containing 100 microM L-NAME, 0.5 microM SMT or 50 microM SMT for 5 min and were subjected to 25 min of ischemia followed by 30 min of reperfusion. Left ventricular developed pressure (LVDP) and total coronary flow (CF) were recorded continuously. After ischemia/reperfusion, a marked expression of iNOS protein was demonstrated by Western blotting, while virtually no iNOS protein was present in hearts without ischemia/reperfusion. Regional myocardial blood flow (RMBF) was measured with colored microspheres. Coronary vasoactive concentration of L-NAME and SMT depressed myocardial function as shown by decreased LVDP, dP/dt(max) and coronary.ow before ischemia. After ischemia the recovery of the total CF was impaired in L-NAME and 50 microM SMT pretreated hearts which was related to homogenous RMBF decrease in the right and left ventricle compared to that in control group. Low concentration SMT (0.5 microM) showed no coronary vasoactive effects before ischemia and attenuated ischemia/reperfusion injury indicated by lower ischemic contracture at 25 min of ischemia and reduced CK and LDH release during reperfusion. Thus, NOS inhibition did not affect blood flow distribution in rat hearts either in the pre-ischemic or reperfusion period. Selective iNOS inhibition reduced ischemic injury by reducing ischemic contracture and CK as well as LDH release during reperfusion.

Animals↗
PubMed2003

[Importance of the Therapeutic Products Act for the ENT practitioner].

The Therapeutic Products Act controls therapeutic products and their fields of application, and classifies them legally. The present regulations on therapeutic products are based on a fundamental concept comprising basic demands, harmonized standards, agreement of the product attributes with the basic demands, and assessment of conformity. Therapeutic products (among which in vitro diagnostics are counted) must comply with definite regulations and are separated from medicines by their mode of action. In addition, therapeutic products must be subject to critical testing. The establishment, management, and use of therapeutic products are, with few exceptions, governed by the Regulations for the Use of Therapeutic Products. To avoid possible risks involved in the application of therapeutic products, a well-functioning system of registration is required, controlled by the Regulations on Therapeutic Products Safety.

Device Approval↗
PubMed2002

Hanle effect in coherent backscattering.

We study the shape of the coherent-backscattering (CBS) cone obtained when resonant light illuminates a thick cloud of laser-cooled rubidium atoms in the presence of a homogenous magnetic field. We observe new magnetic field-dependent anisotropies in the CBS signal. We show that the observed behavior is due to the modification of the atomic-radiation pattern by the magnetic field (Hanle effect in the excited state).

Journal Article↗
PubMed2002

[Stroke management on general medical departments. A multicenter study in Austria].

BACKGROUND AND OBJECTIVE: Despite the claimed superiority of Stroke Units a majority of patients with acute stroke is still treated on general medical departments in many countries. In Austria 90 % of 121 medical departments state that they take care of stroke patients routinely or at least sometimes. Therefore, our aim was to evaluate whether stroke management on medical wards meets up-to-date standards. PATIENTS AND METHODS: 55 medical departments all over Austria participated in a prospective multicenter registry documenting diagnostics, treatment and the in-hospital course of unselected patients admitted with an acute stroke according to a standardised protocol. RESULTS: 1100 patients, 56 % female, with a median age of 75 years were assessed. Median hospital stay was 14 days. In 96 % a cranial computer tomogram was performed. 81 % of cerebral lesions were ischemic, 10 % haemorrhagic. Only 10 % had no risk factor or accompanying medical disease. 31 % suffered at least one medical and 18 % one neurological complication (p = 0.00000003). In-hospital mortality was 17 %, functional outcome was poor in 27 % (Rankin scale [RS] 4 or 5) and good in 56 % (RS 0-3). 74 % of discharged patients could leave to their home, 13 % were transferred to a nursing home and 13 % to a rehabilitation center. 95 % of surviving patients left on either an antiplatelet or an anticoagulant medication and 73 % received antihypertensives. CONCLUSION: Outcome of stroke patients treated on general medical departments seems to be fairly comparable to that commonly reported by neurological Stroke Units. Further improvements may be obtained by implementation of integrated "mixed assessment" units into medical departments.

Aged↗