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Biomedical subjects

Rainer Koch

Publications and source records attributed to Rainer Koch.

At least 19 recordsLinked to original sources
PubMed2007

Valvular heart disease in Parkinson's disease patients treated with dopamine agonists: a reader-blinded monocenter echocardiography study.

Fibrotic valvular heart disease (VHD) has been reported in association with ergot dopamine agonists (DAs), but the current database is insufficient regarding clinical relevance and comparison to data on non-ergot DAs. We evaluated the effects of four DAs (pergolide, cabergoline, ropinirole, pramipexole) on morphology and function of heart valves in patients with Parkinson's disease (PD) to determine the frequency and clinical relevance of DA-induced VHD. A total of 85 patients treated with ergot or non-ergot DAs and 38 age-matched controls were evaluated by transthoracic echocardiography. Valvular pathology was assessed by established criteria of valvular regurgitation and a VHD scoring system. Both grading systems revealed increased frequency of VHD in ergot DA patients compared to both non-ergot DA patients and controls with 22% of ergot DA patients having moderate VHD versus 3% of non-ergot DA patients and none of controls (P = 0.001). We did not find correlations of echocardiographic findings with duration/cumulative dose of treatment, age, or vascular risk factors. Our data suggest that ergot DAs are associated with higher prevalence of VHD compared to non-ergot DAs and controls. Standard echocardiography seems sufficient to detect VHD in PD patients treated with DAs.

Benzothiazoles↗
PubMed2007

Comparison of inhibitory effects of irbesartan and atorvastatin treatment on the renin angiotensin system (RAS) in veins: a randomized double-blind crossover trial in healthy subjects.

Experimental studies point to an interplay between hypercholesterolemia and hypertension, acting through the renin angiotensin system. In a crossover study design with 8 healthy subjects, the authors tested the hypothesis that statin treatment exerts renin angiotensin system-modulating effects in veins by down-regulation of AT1-receptors, resulting in reduced Angiotensin II (Ang II)-induced venoconstriction and by increasing the pleiotropic Ang II-metabolite Ang-(1-7). Irbesartan was used as positive control. Ang II-induced venoconstriction was 49% +/- 9% before and 64% +/- 10% after 30 days of atorvastatin treatment compared to 50% +/- 8% before and 15% +/- 9% after irbesartan (P = .004). Plasma angiotensin levels significantly increased only after irbesartan treatment (Ang II: 35 +/- 4 vs 329 +/- 101 pg/mL [P = .02]; Ang-(1-7): 10 +/- 3 vs 35 +/- 6 pg/mL [P = .01]) compared to atorvastatin treatment (Ang II: 26 +/- 5 vs 31 +/- 4 pg/mL [P = ns]; Ang-(1-7): 9 +/- 2 vs 11 +/- 3 pg/mL [P = ns]). The data indicate that atorvastatin does not inhibit Ang II-induced venoconstriction in vivo and point toward a supportive role of Ang-(1-7) in contributing to the antihypertensive and beneficial vascular effects of irbesartan.

Adult↗
PubMed2006

Continuous cerebral autoregulation monitoring by improved cross-correlation analysis: comparison with the cuff deflation test.

OBJECTIVES: To improve the cross-correlation method for noninvasive, continuous monitoring of cerebral autoregulation, to evaluate this method in humans with intact and impaired autoregulatory capacity, and to compare it to the cuff deflation test. DESIGN AND SETTING: Prospective study in the intensive care unit of a university hospital. PATIENTS AND PARTICIPANTS: Fourteen patients with severe head injury, six patients with subarachnoid hemorrhage, and nine healthy volunteers. INTERVENTIONS AND MEASUREMENTS: Middle cerebral artery flow velocities and arterial blood pressure were monitored continuously. Aaslid's thigh cuff tests were performed and results were scored using Tiecks' model for autoregulation index. Data were then collected without any patient manipulation. The mean time delay between slow spontaneous oscillations of blood pressure and middle cerebral artery flow velocity was calculated by cross-correlation analysis. Data are expressed as median (lower/upper quartile). RESULTS: Healthy subjects had a higher autoregulation index than patients, 5.0 (5.0/5.5) vs. 3.3 (2.0/4.5). Slow oscillations of blood pressure and middle cerebral artery flow velocity showed a time delay of -2.0 s (-2.7/-1.7) in healthy subjects but were almost synchronal in patients, -0.07 s (-0.5/0.45). Inter-method agreement in diagnosing an intact or impaired cerebral autoregulation was obtained in 108 of 147 examinations of autoregulation (73.5%) and was considered moderate. CONCLUSIONS: Cross-correlation analysis may serve as a simple, noninvasive, and continuous measure of cerebral autoregulation. The time delay of -2.0[Symbol: see text]s in healthy subjects is in good agreement with other studies. Short-term autoregulation tests and monitoring techniques based on slow spontaneous oscillations should not be used interchangeably.

Adolescent↗
PubMed2006

[On the efficacy of acute psychiatric day-care treatment in a one-year-follow-up. A comparison to inpatient treatment within a randomised controlled trial].

OBJECTIVE: To compare the effectiveness of acute psychiatric day-hospital treatment and inpatient treatment with respect to a one-year follow-up. METHOD: Within a randomised controlled trial, patients and relatives were assessed at different levels of outcome three months and 12 months after patients' discharge using the Brief Psychiatric Rating Scale (24-Item-Version), the Manchester Assessment of Quality of Life (MANSA), the Groningen Social Disabilities Schedule (GSDS), the Berlin Inventory for the Assessment of Needs (BeBI), and the Involvement Evaluation Questionnaire (IEQ). Using estimation and test of contrasts in linear models of analysis of variance with structured covariance matrix, analyses conducted included data of all n = 191 patients having been included into the German centre of the study. RESULTS: With respect to all measures, day-hospital treatment proved to be at least as effective as inpatient care. CONCLUSION: The study supports earlier findings that showed no differences in long-term effectiveness of acute psychiatric day-hospital treatment as compared to inpatient treatment.

Acute Disease↗
PubMed2006

Quantitative multi-gene expression profiling of primary prostate cancer.

BACKGROUND: This study describes the evaluation of the expression patterns of prostate-related transcripts in 106 matched prostate tissues from prostatectomies as predictors for prostate cancer (PCa). METHODS: Quantitative PCR (QPCR) assays with site-specific hybridization probes were established for four housekeeping genes (GAPDH, HPRT, PBGD, TBP) and nine prostate-related genes (AibZIP, D-GPCR, EZH2, PCA3, PDEF, prostein, PSA, PSCA, TRPM8). RESULTS: The relative mRNA expression levels of AibZIP, D-GPCR, EZH2, PCA3, PDEF, PSA, TRPM8 (all P < 0.001) and prostein (P = 0.019) normalized to the TBP reference gene were significantly higher in malignant compared to non-malignant prostate tissues. Employing receiver-operating characteristic (ROC) analyses, PCA3 was the best single tumor marker with the highest area-under-the-curve (AUC = 0.85). A multivariate logit model for the predictability of the tumor was developed, which employed the relative expression levels of EZH2, PCA3, prostein, and TRPM8 and yielded an AUC of 0.90. CONCLUSIONS: The transcript marker PCA3 is a powerful predictor of primary PCa but the inclusion of EZH2, prostein, and TRPM8 adds even more to the diagnostic power. The finding of a significantly higher mRNA expression of three different genes (prostein, PSA, TRPM8) in organ-confined tumors compared to non-organ-confined tumors as well as the multi-marker PCa prediction model developed in the retrospective model system on prostatectomies could be of clinical importance for diagnostic purposes, and should be verified in diagnostic biopsies.

Aged↗
PubMed2006

Theoretical study of the syn and anti thiophene-2-aldehyde conformers using density functional theory and normal coordinate analysis.

An extensive computational study of thiophene-2-aldehyde conformers syn and anti has been carried out using density functional (DFT). From these calculations, B3LYP/6-31G(d) has been chosen as it produces results remarkably close in comparison with experimental ones, with less demanding computational time. Data obtained from DFT computation were used to perform a normal coordinate analysis to complement and give insight in the experimental vibrational assignment. Calculated dipole moments and relative stabilities of isomers coherently support experimental statements given in the literature.

Aldehydes↗
PubMed2006

Comorbidity is poor predictor of survival in patients undergoing radical prostatectomy after 70 years of age.

OBJECTIVES: To investigate several comorbidity classifications as possible predictors of mortality, because the value of comorbidity as a prognostic factor is uncertain in patients older than 70 years of age and radical prostatectomy in patients older than 70 years is controversial. METHODS: A total of 214 consecutive patients aged 70 years or older who underwent radical prostatectomy from December 1992 to December 2002 were stratified according to the Charlson score, American Society of Anesthesiologists physical status classification, New York Heart Association classification of cardiac insufficiency, classification of angina pectoris from the Canadian Cardiovascular Society, and age (70 to 72 versus 73 to 74 versus 75 years or older). The mean follow-up in the surviving patients was 5.1 years (range 1.3 to 12.5). A sample of 240 consecutive patients aged 67.0 to 69.9 years treated during the same period was used for comparison. The overall and comorbid mortality were the study endpoints. Mantel-Haenszel hazard ratios were calculated. Comparisons were made using the log-rank test. RESULTS: Unlike for patients aged 67.0 to 69.9 years, for those 70 years old or older, only one of the investigated stratifications reached significance as a predictor of mortality. A New York Heart Association classification of 2+ versus 0 was significant for overall mortality (hazard ratio 5.8, P = 0.021) and comorbid mortality (hazard ratio 15.9, P = 0.046). CONCLUSIONS: Comorbidity is of limited prognostic value in patients selected for radical prostatectomy and 70 years old or older.

Age Factors↗
PubMed2006

Is surgery for multiple lung metastases reasonable? A total of 328 consecutive patients with multiple-laser metastasectomies with a new 1318-nm Nd:YAG laser.

OBJECTIVE: Our objective was to define the role of a new 1318-nm Nd:YAG laser for lobe- and parenchyma-saving resection of multiple lung metastases. PATIENTS AND METHODS: From January 1996 to December 2003, a total of 3267 nodules (10/patient) were removed from 328 patients (164 men/164 women, mean age 61 years). Criteria for eligibility were expanded to any primary tumors with no upper limit of metastases given. All parenchymal resections were performed with a new 1318-nm Nd:YAG laser whose effect on lung tissue differs significantly from that of the 1064-nm wavelength owing to a 10-fold higher absorption in water and one-third extinction in blood. In 93%, precision laser resection was achieved. The lobectomy rate was only 7%. RESULTS: Pathologic examination revealed 2546 metastases (8/patient) and lymph node disease in 19%. Complete resections (R0) were achieved in 93% of 177 patients undergoing unilateral procedures with a mean of 3 metastases (range 1%-29%) and 75% of 151 patients having bilateral operations with a mean of 13 metastases (range 2-124). The 5-year survival after R0 was 55% for solitary nodules, 41% for all patients, 28% for 10 metastases, and 26% for 20 or more metastases resected. Outcome was significantly poorer after incomplete resection (7%). No 30-day mortality was observed. Major postoperative complications included prolonged air leaks (n = 2), intrapleural bleeding (n = 2), and late pneumothorax (n = 2); all were treated successfully with a chest tube. CONCLUSION: This new 1318-nm Nd:YAG laser facilitates complete resection of multiple bilateral centrally located metastases and thus is lobe sparing. Resection of 20 or more metastases is reasonable because long-term survival was significantly better than that observed with incomplete resection.

Adult↗
PubMed2006

Theoretical 49Ti NMR chemical shifts.

49Ti chemical shifts for a total of 20 titanium complexes are reported, and several levels of theory are evaluated in order to identify a reliable approach for the calculation of titanium NMR data. The popular B3LYP/6-31G(d)//B3LYP/6-31G(d) proves to give very good agreement with experimental data over a range from 1,400 to -1,300 ppm. The MP2/6-31G(d)//MP2/6-31G(d) level computes even smaller average deviations but fails for TiI(4). This behavior together with its huge demand for computational resources requires careful handling of this theoretical level. In addition, NMR data for five titanium fulvene (or related) complexes are given.

Magnetic Resonance Spectroscopy↗
PubMed2006

An unusual reaction of the natural compound benaphthamycin B: theoretical study of a model system.

The surprising and complex transformation of benaphthamycin B to give quinone 2a is investigated theoretically with a model compound, 1,5-dihydroxy-4-methoxy-2,3-dimethylanthraquinone (3). The detailed study is performed using both DFT and perturbation theory under inclusion of solvent effects. Several individual steps (reduction and hydrolysis, water elimination, ether cleavage, and oxidation) of the proposed reaction cascade calculated at the PCM-MP2/6-31G(d)//B3LYP/6-31G(d) level of theory are presented and discussed. It is shown that the key step, the ether cleavage as an S(N)2 reaction leading to the anthrone 12a, possesses a smaller activation barrier compared to the alternative process yielding 12b. Therefore, the formation of the thermodynamically preferred model quinone 13a is also the kinetically favored pathway: The results of the calculated model reaction should also be valid for benaphthamycin B (1).

Benz(a)Anthracenes↗
PubMed2006

Laser resection technique and results of multiple lung metastasectomies using a new 1,318 nm Nd:YAG laser system.

BACKGROUND AND OBJECTIVES: Advantages of a new 1,318 nm Nd:YAG laser based on multiple lung metastasectomies are shown. STUDY DESIGN/MATERIALS AND METHODS: Ninety-three percent of 328 patients with metastases (8/patient, range 1-124) had precision laser resections (lobectomy-rate reduced to 7%); this laser delivers 20 kW/cm(2) 1,318 nm power densities with 400 microm fibers, and a focussing handpiece. Absorption in water is tenfold higher. RESULTS AND CONCLUSIONS: Between 1/1996 and 12/2003 in 328 patients (164 males/females, 61 years) 3,267 nodules were removed. Pathologic examination revealed 2,546 metastases (range 3-80 mm) from kidney (n = 112), colorectal (n = 91), and breast cancers (n = 35). In 85% of patients where the complete resection was achieved the 5-year survival was 41%. For remaining 15% (incomplete resection) the 5-year survival was 7%. Five-year survival for patients with 10 (and more) metastases was 28%, for patients with 20 (and more) was 26%. No 30-day mortality was observed. CONCLUSION: This new laser system facilitates any kind of parenchymal lung resection in lobe-sparing manner and in case of complete resection improves significantly the survival.

Adult↗
PubMed2006

[Predictors of the discharge status in acute day-hospital and inpatient care - a comparison between the two settings within a randomised controlled trial].

OBJECTIVE: To search for predictors of the discharge status in day-hospital patients and inpatients, within a randomized controlled trial on the effectiveness of acute psychiatric day hospital treatment as compared to inpatient treatment. METHOD: The study was conducted at the Department of Psychiatry and Psychotherapy, Dresden University of Technology. Regression analyses assessing the relationship between theoretically chosen predictor variables and the discharge status as measured using the Brief Psychiatric Rating Scale (BPRS 4.0) were conducted on a sample of 69 day-hospital patients and a sample of 76 inpatients. RESULTS: In both settings, admission status was the strongest predictor of discharge status. As concerns day-hospital patients, those suffering from a personality disorder as well as those showing a higher degree of social disability were discharged with a higher level of psychopathological symptoms. Among inpatients, those suffering from an anxiety, obsessive-compulsive, or adjustment disorder as well as those being retired or unemployed benefited less from treatment. CONCLUSIONS: Given the explorative character of the present study, further prospective studies are needed in order to cross-validate findings on the potential criteria for allocating acute mentally ill either to day-hospital or inpatient treatment.

Adult↗
PubMed2006

Omega-3 fatty acids improve the diagnosis-related clinical outcome.

OBJECTIVE: Supplementation of clinical nutrition with omega-3 fatty acid in fish oil exerts immune-modulating and organ-protective effects, even after short-term application. The aim of this study was to evaluate dose-dependent effects of parenteral supplementation of a 10% fish oil emulsion (Omegaven, Fresenius-Kabi, Bad Homburg, Germany) on diagnosis- and organ failure-related outcome. DESIGN: Prospective, open label, multiple-center trial. PATIENTS AND METHODS: A total of 661 patients from 82 German hospitals receiving total parenteral nutrition for > or =3 days were enrolled in this study. The sample included 255 patients after major abdominal surgery, 276 with peritonitis and abdominal sepsis, 16 with nonabdominal sepsis, 59 after multiple trauma, 18 with severe head injury, and 37 with other diagnoses. The primary study end point was survival; secondary end points were length of hospital stay and use of antibiotics with respect to the primary diagnosis and the extent of organ failure. Multiple quasi-linear and logistic regression models were used for calculating diagnosis-related fish oil doses associated with best outcome. RESULTS: The patients enrolled in this survey were (mean +/- sd) 62.8 +/- 16.5 yrs old, with a body mass index of 25.1 +/- 4.2 and Simplified Acute Physiology Score (SAPS) II score of 32.2 +/- 13.6. Length of hospital stay was 29.1 +/- 18.7 days (12.5 +/- 14.8 days in the intensive care unit). Total parenteral nutrition, including fish oil (mean, 0.11 g.kg(-1).day(-1)), was administered for 8.7 +/- 7.5 days and lowered hospital mortality as predicted by Simplified Acute Physiology Score II from 18.9% (95% confidence interval, 17.4-20.4%) to 12.0% (p < .001). The fish oil dose.kg.day did correlate with beneficial outcome (intensive care unit stay, hospital stay, mortality). Fish oil had the most favorable effects on survival, infection rates, and length of stay when administered in doses between 0.1 and 0.2 g.kg(-1).day(-1). Lower antibiotic demand by 26% was observed when doses of 0.15-0.2 g.kg(-1).day(-1) were infused as compared with doses of <0.05 g.kg(-1).day(-1). After peritonitis and abdominal sepsis, multiple quasi-linear regression models revealed a fish oil dose for minimizing intensive care unit stay of 0.23 g.kg(-1).day(-1) and an inverse linear relationship between dosage and intensive care unit stay in major abdominal surgery. CONCLUSION: Administration of omega-3 fatty acid may reduce mortality, antibiotic use, and length of hospital stay in different diseases. Effects and effect sizes related to fish oil doses are diagnosis dependent. In view of the lack of substantial study literature concerning diagnosis-related nutritional single-substrate intervention in the critically ill, the present data can be used in formulating hypotheses and may serve as reference doses for randomized, controlled studies, which may, for instance, confirm the value of omega-3 fatty acid in the adjunctive therapy of peritonitis and abdominal sepsis.

Critical Illness↗
PubMed2006

Comparison of the clinical value of complexed PSA and total PSA in the discrimination between benign prostatic hyperplasia and prostate cancer.

BACKGROUND: To compare the clinical value of the measurement of complex and total PSA in the discrimination between benign prostatic hyperplasia (BPH) and prostate cancer. METHODS: In serum samples collected from 166 men with histopathologically proven clinically localized prostate cancer and of 97 men with BPH, total prostate-specific antigen (PSA), complexed PSA and the free to total PSA ratio were determined. The statistical analysis was done by the comparison of the receiver operator characteristic (ROC) curves. RESULTS: The areas under the ROC curves were 0.776 for total PSA, 0.799 for complexed PSA (total PSA vs. cPSA: p < 0.0001) and 0.812 for the free to total PSA ratio. With a cut-off of 3.0 ng/ml for complexed PSA, the sensitivity was 90%, the specificity 58%, the positive and the negative predictive values 79 and 78%, respectively. With a cut-off of 4.0 ng/ml for total PSA, the sensitivity was 87%, the specificity 59%, the positive and the negative predictive values were 78 and 72%, respectively. CONCLUSIONS: There was a statistically significant advantage for complexed PSA compared to total PSA in the discrimination between BPH and prostate cancer. The difference was, however, small and its clinical relevance is questionable.

Diagnosis, Differential↗
PubMed2005

Qualitative computer aided evaluation of dental impressions in vivo.

OBJECTIVES: Clinical investigations dealing with the precision of different impression techniques are rare. Objective of the present study was to develop and evaluate a procedure for the qualitative analysis of the three-dimensional impression precision based on an established in-vitro procedure. The zero hypothesis to be tested was that the precision of impressions does not differ depending on the impression technique used (single-step, monophase and two-step-techniques) and on clinical variables. METHODS: Digital surface data of patient's teeth prepared for crowns were gathered from standardized manufactured master casts after impressions with three different techniques were taken in a randomized order. Data-sets were analyzed for each patient in comparison with the one-step impression chosen as the reference. The qualitative analysis was limited to data-points within the 99.5%-range. Based on the color-coded representation areas with maximum deviations were determined (preparation margin and the mantle and occlusal surface). To qualitatively analyze the precision of the impression techniques, the hypothesis was tested in linear models for repeated measures factors (p < 0.05). RESULTS: For the positive 99.5% deviations no variables with significant influence were determined in the statistical analysis. In contrast, the impression technique and the position of the preparation margin significantly influenced the negative 99.5% deviations. SIGNIFICANCE: The influence of clinical parameter on the deviations between impression techniques can be determined reliably using the 99.5 percentile of the deviations. An analysis regarding the areas with maximum deviations showed high clinical relevance. The preparation margin was pointed out as the weak spot of impression taking.

Computer-Aided Design↗
PubMed2005

Transcript quantification of Dresden G protein-coupled receptor (D-GPCR) in primary prostate cancer tissue pairs.

Recently, we identified the novel protein D-GPCR (Dresden G protein-coupled receptor) which is selectively overexpressed in human prostate cancer (PCa) and belongs to the subfamily of odorant-like orphan GPCRs. Quantification of D-GPCR transcripts in paired malignant and non-malignant prostate tissues of 106 patients with primary PCa by real-time PCR demonstrated a significant up-regulation of this gene in tumor samples. Furthermore, its expression increases with higher tumor stages and grades. The evaluation of D-GPCR expression as a potential molecular tumor marker was performed by receiver-operating characteristic curve (ROC) analysis resulting in an area under the curve (AUC) value of 0.6452. Hence, the evaluation of D-GPCR as possible additive diagnostic tool and putative therapy target appears promising.

Aged↗
PubMed2005

Factors predicting survival in stage IV colorectal carcinoma patients after palliative treatment: a multivariate analysis.

BACKGROUND: The prognostic impact of primary tumor resection in patients presenting with unresectable synchronous metastases from colorectal carcinoma (CRC) is not well established. In the present study, we analyzed fifteen factors to define the value of primary tumor resection with regard to prognosis. PATIENTS AND METHODS: We identified 186 consecutive patients with proven stage IV CRC from the year 1995 to 2001. Variables were tested for their relationship to survival in univariate analyses with the Kaplan-Meier method and the log rank test. Factors that showed a significant impact were included in a Cox proportional hazards model. The tests were repeated for 107 patients who had no symptoms from their primary tumor. RESULTS: Overall there were six independent variables with a relationship to survival: performance status, ASA-class, CEA level, metastatic load, extent of primary tumor, and chemotherapy. In the asymptomatic patients we investigated 13 factors, 3 of which proved to be independent predictors of survival: performance status, CEA level, and chemotherapy. Resection of primary tumor was only predictive of survival if in-hospital mortality was excluded. CONCLUSION: Resection of the tumor, if possible, is doubtless the best option for stage IV CRC patients with severe symptoms caused by their primary tumor. In asymptomatic patients, chemotherapy is preferable to surgery.

Aged↗