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K Koch

Publications and source records attributed to K Koch.

At least 19 recordsLinked to original sources
PubMed2006

Double-blind, randomized, placebo-controlled study to evaluate the effects of tegaserod on gastric motor, sensory and myoelectric function in healthy volunteers.

BACKGROUND: The effects of tegaserod on gastric accommodation and postprandial satiety remain unclear. AIM: To compare the effects of tegaserod 6 mg twice daily vs. placebo on gastric volumes, postprandial symptoms, gastric emptying, small bowel transit and the surface electrogastrogram in female and male healthy volunteers. METHODS: Randomized, double-blind, placebo-controlled study evaluated gastric function before and after 7 days of tegaserod 6 mg twice daily (n = 21) vs. placebo (n = 20) in healthy volunteers. Validated methods were used to study gastric emptying, myoelectrical activity, volumes and satiation postnutrient challenge. RESULTS: There were no significant effects of tegaserod on the primary endpoints assessing gastric function: emptying of solids or liquids, total gastric volumes or myoelectrical activity. Maximum tolerated volume and aggregate symptom score with nutrient challenge on placebo were 1,035 mL (+/-44) and 130 (+/-15) vs. 989 mL (+/-43) and 117 (+/-15) during tegaserod, respectively (all P = N.S.). Postprandial change in proximal gastric volume by single photon emission-computed tomography was decreased in females on tegaserod (246 +/- 30) vs. placebo (358 +/- 32) (P = 0.015). Proximal fasting volumes in females were increased on tegaserod (126 +/- 12) vs. placebo (92 +/- 13) (P = 0.066). CONCLUSIONS: While tegaserod decreased proximal gastric volume change after a meal, it does not appear to have significant effects on gastric motor and sensory function in healthy individuals. Further studies are required in patients with disturbances of gastric motor and sensory function.

Administration, Oral↗
PubMed2006

Crystallinity of plant epicuticular waxes: electron and X-ray diffraction studies.

The crystal structure of the epicuticular waxes of 35 plant species has been examined by electron diffraction and X-ray powder diffraction. The waxes include the most common morphological wax types such as platelets, tubules, films and rodlets. Most of them were prepared with a special mechanical isolation method, which preserves the original crystal structure. Solvent-extracted recrystallized plant waxes were compared with mechanically isolated samples. The waxes were found to occur in three different crystal structures. Most of the waxes exhibited an orthorhombic structure which is the most common for aliphatic compounds. Tubules containing mainly secondary alcohols showed diffraction reflections of a triclinic phase; broad reflection peaks indicated a significant disorder. Ketones, in particular beta-diketone tubules, displayed the reflections of a hexagonal structure. Mixtures of different phases could be identified. For most of the waxes, the 'long spacing' diffraction reflections indicated a layer structure with the characteristics of the major component. Others showed no 'long spacing' reflections indicating a strong disorder of the molecular layers.

Crystallization↗
PubMed2006

[Hepatic resections. Analysis of data from the Tumor Documentation Center in the state of Brandenburg, Germany, focusing on liver metastases of colorectal carcinoma].

BACKGROUND: Data from the Brandenburg Tumor Documentation Center (TDCB) in Germany were analyzed for an overview of the current treatment standards of liver surgery in that state. MATERIAL AND METHODS: The analysis was based on prospective data from a total of 37,165 patients diagnosed with malignant tumors between 1 January 1999 and 31 December 2004. Of these patients, 3,986 were diagnosed with liver metastases and 554 had primary tumors of the liver or bile duct. Liver metastases of colorectal carcinoma were reported in 1,299. RESULTS: Analysis confirmed that resection of colorectal metastases (51%) and primary liver or bile duct tumors (23.1%) is by far the most frequent indication for liver surgery. Liver metastasis was developed by 29.2% (n=1299) of patients with colorectal carcinoma. Of the patient total, 71.5% showed evidence of liver metastasis already present when colorectal carcinoma was diagnosed. Of 248 patients who had received liver surgery after diagnosis of liver metastases of a colorectal carcinoma, 114 (46%) underwent hepatic segment resection, which was thus performed in only 8.8% (n=114) of patients with liver metastases after colorectal carcinoma (n=1299). CONCLUSIONS: Since only 8.8% of those with liver metastases underwent curative hepatic segment resection, we can conclude that if patients and doctors were provided with adequate information on the curative potential of this surgical method along with regular consultations with surgeons experienced in liver surgery, the result on resection rates would be positive. Data from tumor documentation centers enable selective analysis of the oncological situation of specific diseases.

Adult↗
PubMed2005

Structural analysis of wheat wax (Triticum aestivum, c.v. 'Naturastar' L.): from the molecular level to three dimensional crystals.

In order to elucidate the self assembly process of plant epicuticular waxes, and the molecular arrangement within the crystals, re-crystallisation of wax platelets was studied on biological and non-biological surfaces. Wax platelets were extracted from the leaf blades of wheat (Triticum aestivum L., c.v. 'Naturastar', Poaceae). Waxes were analysed by gas chromatography (GC) and mass spectrometry (MS). Octacosan-1-ol was found to be the most abundant chemical component of the wax mixture (66 m%) and also the determining compound for the shape of the wax platelets. The electron diffraction pattern showed that both the wax mixture and pure octacosan-1-ol are crystalline. The re-crystallisation of the natural wax mixture and the pure octacosan-1-ol were studied by scanning tunnelling microscopy (STM), atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Crystallisation of wheat waxes and pure octacosano-1-ol on the non polar highly ordered pyrolytic graphite (HOPG) led to the formation of platelet structures similar to those found on the plant surface. In contrast, irregular wax morphologies and flat lying plates were formed on glass, silicon, salt crystals (NaCl) and mica surfaces. Movement of wheat wax through isolated Convallaria majalis cuticles led to typical wax platelets of wheat, arranged in the complex patterns typical for C. majalis. STM of pure octacosan-1-ol monolayers on HOPG showed that the arrangement of the molecules strictly followed the hexagonal structure of the substrate crystal. Re-crystallisation of wheat waxes on non-polar crystalline HOPG substrate showed that technical surfaces could be used to generate microstructured, biomimetic surfaces. AFM and SEM studies proved that a template effect of the substrate determined the orientation of the re-grown crystals. These effects of the structure and polarity of the substrate on the morphology of the epicuticular waxes are relevant for understanding interactions between biological as well as technical surfaces and waxes.

Crystallization↗
PubMed2005

Is granulocyte colony-stimulating factor level predictive for human IVF outcome?

BACKGROUND: We investigated granulocyte colony-stimulating factor (G-CSF) in human reproduction. METHODS: From a total sample of 93 patients, we analysed in group 1 (n = 82) the level of G-CSF and estradiol (E(2)) in serum and follicular fluid (FF) on day of follicular puncture (FP). Furthermore, in response to ovarian stimulation, G-CSF levels in serum were compared between low (n = 11), moderate (n = 53) and high (n = 18) response patients. In group 2 (n = 23) serum for G-CSF assessment was collected throughout menstrual cycle until gestation. Group 3 (n = 11) patients with endometriosis were assessed for G-CSF in serum and FF on day of FP without further differentiation. RESULTS: G-CSF in FF was higher than in serum (P < 0.01). G-CSF in serum increased from low through moderate to high response (P < 0.001); pregnancy rates were 0, 24.5 and 33.5% respectively. G-CSF in serum increased throughout stimulation, reached a peak with ovulation induction (P = 0.01) and decreased until embryo transfer (P=0.001). G-CSF level only in pregnant patients (n = 11) increased from embryo transfer to implantation to gestation (P = 0.005). In endometriosis patients G-CSF in serum and FF was lower than in non-endometriosis patients (P < or = 0.03) and corresponded with low response patients. CONCLUSIONS: G-CSF is involved in follicle development and may be a predictor of IVF outcome.

Adult↗
PubMed2005

Understanding of the structure, bonding, formation and decomposition of metalloid aluminum clusters--a Fourier transform ion cyclotron resonance study of solid AlCp*.

The investigation of the tetrahedral Al4Cp*4 cluster with Fourier transform ion cyclotron resonance mass spectrometry using laser desorption /ionization as the ionization method results in a couple of aluminum cluster compounds AlxCp*+y (x > y) with up to eight aluminum atoms. MS(n) experiments are performed in order to understand the formation and reactivity of the different species. Quantum chemical calculations of the structure and energy for all compounds identified complete this study.

Journal Article↗
PubMed2004

Assessment of right ventricular function by 16-detector-row CT: comparison with magnetic resonance imaging.

The purpose of this study was to determine right ventricular (RV) function from 16-detector-row CT by using two different software tools in comparison with MRI. Nineteen patients underwent cardiac CT. (1) With semiautomated contour detection software end-diastolic and end-systolic RV volumes were determined from short-axis CT reformations (MPR) created at every 10% of the RR-interval. (2) End-systolic and end-diastolic axial images were transformed to 3D to determine the volumes by using a threshold-supported reconstruction algorithm. Steady-state free-precession cine-MRI of the heart was done in short-axis orientation. RV function could not be analyzed in one patient because of sternal wire artifacts in MRI. Mean end-diastolic (155.4+/-54.6 ml) and end-systolic (79.1+/-37.0 ml) RV volumes determined with MPR correlated well with MRI [151.9+/-53.7 ml (r=0.98) and 75.0+/-36.0 ml (r=0.96), respectively (P<0.001)]. RV stroke volume (76.2+/-20.2 ml for MPR-CT, 76.9+/-20.7 ml for MRI, r=0.93) showed a good correlation and RV ejection fraction (50.8+/-8.4% for MPR-CT, 51.9+/-7.4% for MRI, r=0.74) only a moderate one. Threshold supported 3D reconstructions revealed insufficient correlations with MRI (r=0.31-0.59). MPR-based semiautomated analysis of cardiac 16 detector-row CT allows for RV functional analysis. The results correlate well with MRI findings. Threshold value-supported 3D reconstructions did not show satisfying results because of inhomogeneities of RV contrast enhancement.

Aged↗
PubMed2004

[Assessment of global and regional left ventricular function with a 16-slice spiral-CT using two different software tools for quantitative functional analysis and qualitative evaluation of wall motion changes in comparison with magnetic resonance imaging].

PURPOSE: To determine global and regional left ventricular (LV) function from retrospectively gated multidetector row computed tomography (CT) by using two different semiautomated analysis tools and to correlate the results with those of magnetic resonance imaging (MRI). MATERIALS AND METHODS: Nineteen patients (5 females, 14 males, mean age 69 years) underwent 16-slice spiral-CT (MS-CT) with standard technique without administration of beta-blockers for a decrease in the cardiac rate. Ten series of images were reconstructed at every 10 % of the RR-interval. With commercially available software capable of semiautomated contour detection, end-diastolic and end-systolic LV volumes (EDV and ESV) were determined from short-axis multiplanar CT reformations (MPR). Axial images of the end-systolic and end-diastolic cardiac phase were transformed to 3D volumes (3D) to determine EDV and ESV by using a threshold-supported reconstruction algorithm dependent on the contrast enhancement of the left ventricle. Steady-state free-precession cine MR images were acquired in short-axis orientation on the same day in all but one patient. Regional wall motion was assessed qualitatively in 17 left ventricular segments and classified as normo-, hypo-, a- or dyskinetic. Bland-Altman analysis was performed to calculate limits of agreement and systematic errors between CT and MRI. RESULTS: For MPR/3D, mean end-diastolic (144.4/142.8 mL +/- 67.5/67.1) and end-systolic (66.4/68.7 mL +/- 52.1/49.9) LV volumes as determined with MS-CT correlated well with MRI measurements (147.6 mL +/- 67.6 [ r = 0.98/0.96] and 73.3 mL +/- 55.5 [ r = 0.98/0.98], respectively [ p <.001]). LV stroke volume (77.6/74.1 +/- 19.2/23.4 mL for CT vs. 74.4 mL +/- 18.4 for MRI, r = 0.92/0.74) and LV ejection fraction (58.6/55.9 % +/- 13.5/13.7 for CT vs. 55.6 % +/- 13.5 for MRI, r = 0.95/0.91) also showed good correlation (p <.001). Regional wall motion analysis revealed agreement between CT and MRI in 316/323 (97.8 %) myocardial segments. CONCLUSION: Semiautomated analysis of 16-detector row CT data sets enables global and regional volumetric and functional analysis. The CT results correlate well with MRI findings for short axis MPR and for 3D volume reconstructions, with a higher statistical spread for the 3D method. The underestimation of end-systolic and end-diastolic volumes with CT may be caused by partial volume averaging due to the lower temporal resolution as compared with MRI.

Aged↗
PubMed2002

Smoking modulates neuroendocrine responses to ipsapirone in patients with panic disorder.

Reduced 5-HT1A-receptor responsiveness has been reported in patients with panic disorder(PD) and/or agoraphobia (PDA). Although many of these patients are regular smokers, it has not been examined whether psychological or neurobiological effects induced by the selective 5-HT1A-receptor agonist, ipsapirone, are affected by the smoking status of the patients. In order to clarify this question neuroendocrine challenges with oral doses of ipsapirone (0.3 mg/kg) and placebo were performed in 39 patients with PDA, and results were compared between patients who smoked (>10 cigarettes per day, n = 17) and patients who had been non-smokers for at least two years (n = 22). Patients who were smokers (but did not smoke during the challenge procedure) had significantly reduced baseline concentrations of cortisol and a significantly lower body temperature. In comparison to placebo, administration of ipsapirone was associated with significant increases of various psychological symptoms and plasma cortisol concentrations. The subgroup of PD patients who were smokers showed significantly higher cortisol responses to ipsapirone than non-smokers. In conclusion, smoking status has to be taken into account when assessing the responsiveness of 5-HT1A receptors in patients with psychiatric disorders. The prevention of smoking during challenge sessions might not be the ideal approach in heavy smokers, since sudden abstinence from smoking is likely to affect neurobiological and possibly psychological responses to ipsapirone.

Adult↗
PubMed2002

Cryosurgical treatment of genuine trigeminal neuralgia.

A newly developed cryoprobe for peripheral nerves allows surgeons to freeze branches of the trigeminal nerve at the infraorbital or the mandibular foramen without exposing the nerve or damaging the surrounding tissue. The probe has an outer diameter of 2.7mm, and a vacuum-insulated shaft to protect the adjacent tissue. It is designed to be inserted transmucosally. The cryoprobe was used in 19 patients to freeze the infraorbital nerve or the inferior alveolar nerve. At 4-8 months after cryotherapy sensation in the areas innervated by the treated nerve had returned, but pain was absent for at least 6 months. The pain recurred in 13 out of 19 patients within 6-12 months. However, it was possible to repeat the cryotherapy as the procedure was not stressful. Cryosurgery widens the range of methods available to treat trigeminal neuralgia.

Cryosurgery↗
PubMed2002

[Percutaneous vertebroplasty].

PURPOSE: To describe the procedure of percutaneous vertebroplasty and to present our first clinical results of patients treated for benign or malignant painful vertebral body disease. MATERIAL AND METHODS: We performed percutaneous vertebroplasty in 31 painful lesions of the spine. Liquid bone cement was injected into the affected vertebral body using fluoroscopic guidance through a bilateral transpedicular approach. Etiology of the bone disease was assessed by biopsy. Pain intensity was assessed before and 1 week after the procedure by standardized catalogue. RESULTS: Percutaneous vertebroplasty was performed in 17 thoracic and in 14 lumbar spine bodies of benign (n = 23) or malignant (n = 8) disease; no clinically relevant complications occurred. All patients reported significant pain relief 1 week after the intervention. One week after treatment, patients were pain-free in 15/31 vertebral bodies, and reported mild residual pain not necessitating narcotic medication in 16/31 cases. CONCLUSION: In accordance with the literature, percutaneous vertebroplasty proved to be a highly effective, minimal invasive interventional procedure to treat severely painful bone lesions of benign and malignant origin.

Adult↗
PubMed2002

Differing effects of low-dose estrogen-progestin therapy and pravastatin in postmenopausal hypercholesterolemic women.

BACKGROUND: Most studies examining the potential cardioprotective effects of postmenopausal estrogen have been undertaken in healthy women, with doses that may not be appropriate for long-term intervention. New low-dose estrogen-progestin regimens alleviate postmenopausal symptoms with a favorable side-effect profile; however, little is known of the impact of such regimens in women at increased risk of cardiovascular disease. Hence, we have evaluated the effects of low-dose oral estrogen-progestin therapy on serum lipoprotein lipids, brachial artery reactivity and fibrinogen in hypercholesterolemic postmenopausal women in direct comparison with the effects of pravastatin, a lipid-lowering agent known to reduce cardiovascular events in women. METHODS: In a randomized, double-blind, double-dummy, parallel trial, we studied the effects of continuous combined estrogen-progestin therapy (1 mg 17beta-estradiol with 500 micro g norethisterone acetate daily) or pravastatin (20 mg daily) in 72 postmenopausal women with fasting serum low-density lipoprotein (LDL) cholesterol levels greater than 124 mg/dl after an 8-week run-in diet, over a 24-week period. The primary end-point was percentage change in LDL cholesterol from baseline. RESULTS: The intention-to-treat population comprised 65 women, mean age 59 +/- 6.3 years, and 29 in each group completed the trial. Diet alone reduced LDL cholesterol significantly in both treatment groups, in association with a reduction in weight during this period. Compared with respective baseline values, pravastatin decreased LDL cholesterol and total cholesterol to a greater extent than hormone therapy (p = 0.0001 and 0.003 for difference between treatments, respectively). High-density lipoprotein (HDL) cholesterol levels decreased with hormone therapy, but did not change with pravastatin (p = 0.01). Lipoprotein(a) decreased significantly with hormone therapy only (-14%, 95% confidence interval (CI) -21 to -6%, p = 0.01 for difference between groups). Brachial artery flow-mediated dilatation (FMD) was impaired at baseline, and this increased with hormone therapy (absolute mean change in artery diameter as percentage units 2.07, 95% CI 0.57-3.57, p = 0.009) versus no change with pravastatin (0.19, 95% CI -1.1 to 1.5, p = 0.78), with a near-significant difference between the two groups (p = 0.058). A significant correlation between improved brachial artery FMD and reduction in LDL cholesterol was not observed. Fibrinogen decreased significantly in both treatment groups with no difference between treatments. CONCLUSIONS: In postmenopausal hypercholesterolemic women, pravastatin and hormone therapy exhibited divergent effects. The former lowered total and LDL cholesterol more effectively, whereas hormone therapy lowered lipoprotein(a) significantly and improved brachial artery endothelium-dependent dilatation, independent of the reduction in LDL cholesterol. The modest increase in brachial artery FMD seen is consistent with hypercholesterolemia compromising endothelial integrity, and suggests that the important effect of estrogen on the endothelial microenvironment may be attenuated in women with endothelial dysfunction.

Aged↗
PubMed2001

Inhibition of duck hepatitis B virus replication by intrahepatic expression of an antiviral resistance gene.

Resistance genes coding for inhibitors of hepadnaviral replication, such as ribozymes, antisense RNA, and dominant negative mutants have been shown to be effective in transfected hepatoma cells. In vivo studies, however, are not available to date. Here we expanded the use of the duck hepatitis B virus (DHBV) model for studying antiviral resistance genes in vivo. Animals were experimentally infected by intravenous injection of DHBV-positive serum in ovo. The use of recombinant human adenovirus type 5 and avian adenovirus CELO for gene transfer was evaluated. Adenovirus type 5 transduced more than 95% and CELO less than 1% of embryonic hepatocytes in vivo. Adenovirus type 5 interfered with DHBV replication (viral cross-talk), but this effect was moderate and did not preclude analysis of specific antiviral effects. Thus adenoviral transfer of a dominant negative mutant prior to DHBV infection (intracellular immunization) yielded 100-fold suppression of viral replication compared to the green fluorescent protein marker gene. Neither gene was toxic. These data demonstrate that a prototype anthepadnaviral resistance gene is functional in vivo. Duck embryos represent a useful model for evaluating gene therapeutic strategies in vivo without the need for large scale preparations of gene delivery vehicles.

Adenoviridae↗
PubMed2001

[Metastatic epidural spinal compression: prognostic factors and results of radiotherapy].

BACKGROUND: The metastatic epidural spinal cord compression is an oncologic emergency. Presently, there is no agreement on a standard diagnostic or therapeutic algorithm. In spite of improvement in diagnostic imaging, a great proportion of patients are plegic at the time of the first presentation. PATIENTS AND METHODS: Therapy charts of 53 consecutive patients--31 male and 22 female--with metastatic epidural spinal cord compression treated with radiation therapy only have been analyzed. Median age was 60 years. The most frequent primary tumors were bronchogenic carcinoma (13 patients), breast cancer (ten patients) and prostate cancer (ten patients). RESULTS: MRI was the most sensitive diagnostic tool in detecting spinal cord compression. Plain X-ray films were not useful. Pain symptoms were improved in 66% of the patients. The most important prognostic factor was the pretreatment mobility status. 94% of the ambulatory patients kept their walking ability, but only one plegic patient could walk again after radiation therapy (p < 0.001). Patients whose back pain was presented to an oncologist were more likely to keep their walking ability by the end of the therapy. Patients with bronchogenic cancer and plegic patients had a significantly worse survival. CONCLUSION: Patients with a known malignant tumor and progressive or axial back pain should undergo MRI scan to rule out spinal cord compression. For patients without severe neurologic deficit and MRI proven epidural compression, radiation therapy is able to preserve walking ability and reduce pain. For patients with neurologic symptoms radiation therapy should start within 24 hours.

Adenocarcinoma↗
PubMed2001

Movement and regeneration of epicuticular waxes through plant cuticles.

Regeneration of plant epicuticular waxes was studied in 24 plant species by high-resolution scanning electron microscopy. According to their regeneration behaviour, four groups could be distinguished: (i) regeneration occurs at all stages of development; (ii) regeneration occurs only during leaf expansion; (iii) regeneration occurs only in fully developed leaves; (iv) plants were not able to regenerate wax. Wax was removed from the leaves with water-based glue and a liquid polymer, i.e. water-based polyurethane dispersion. In young leaves these coverings could not be removed without damaging the leaves. After a few days, waxes appeared on the surface of these polymer films, which still adhered to the leaves. It is concluded that waxes move through the cuticle in a process similar to steam distillation. This hypothesis could be further substantiated in refined in vitro experiments. Wax isolated from Eucalyptus globulus was applied to a filter paper, subsequently covered with a liquid polymer and fixed onto a diffusion chamber filled with water. The diffusion chamber was put into a desiccator. After 8-10 days at room temperature, crystals similar in dimensions and shape to in situ crystals appeared on the surface of the polyurethane film. This indicates that waxes in molecular dimensions move together with the water vapor that permeates through the polymer membrane. Based on these results, we propose a new and simple hypothesis for the mechanism of wax movement: the molecules that finally form the epicuticular wax crystals are moved in the cuticular water current.

Biological Transport↗
PubMed2001

Is nausea associated with chronic hepatitis C infection?

OBJECTIVES: Hepatitis C virus is a common chronic infection that is widely associated with symptoms of fatigue and pain in the right upper quadrant. Nausea may be an underrecognized symptom. This study was designed to study the frequency of nausea in patients with hepatitis C virus infection compared to controls. METHODS: A cross-sectional study design with consecutive outpatients was used. Three groups were administered a dyspepsia and a previously validated Nausea Profile questionnaire. Univariate and multivariate analysis was performed. RESULTS: A total of 64 hepatitis C virus (HCV) patients, 53 liver disease controls (LC), and 64 normal controls (NC) were studied. An increased period prevalence of nausea was found in HCV patients 43% versus 29.7% in NC and 18.9% in LC (p = 0.009). There was an increased frequency of fatigue and abdominal pain in HCV patients over 1 month compared to LC and NC combined (p = 0.0001 and 0.0065 respectively). The Nausea Profile score revealed statistically higher total scores and higher subscale scores in the HCV group compared to controls. The total NP score expressed as a percentage of the maximum was 27% in HCV versus 12.7% for LC and 9.2% for NC (p = 0.0005). The odds of nausea using logistic regression were 2.1 CI (1.0-4.5) in HCV patients compared to controls (p = 0.05). Using linear regression, higher Nausea Profile scores were found to be independently associated with the diagnosis of HCV (.0005), fatigue (p = 0.0003), and abdominal pain (p = 0.0001). CONCLUSIONS: HCV infection is associated with an increased risk for nausea. The strong association between abdominal pain and nausea may be a clue to the etiology of nausea in these patients. Further etiological studies are needed.

Abdominal Pain↗