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Biomedical subjects

R Kluge

Publications and source records attributed to R Kluge.

At least 19 recordsLinked to original sources
PubMed2006

Renal function and urine drainage after conservative or operative treatment of primary (obstructive) megaureter in infants and children.

UNLABELLED: We examined renal function and urinary drainage of children with primary megaureter (PMU) in dependence on conservative or operative treatment. MATERIAL AND METHODS: The retrospective analysis covering the years 1994 to 2000 comprised children at an age of 0-7 years with 35 PMU. Sonography, dynamic MAG3 renography as well as endogenic creatinine clearance (GFR) were used to assess drainage and the renal function. Temporary urinary diversion was established in fourteen patients of both groups. In 14 children with 16 PMU a ureteroneocystostomy (UNC) was performed. The average observation period was 30 months (11-108). RESULTS: The children of the UNC group differed from the non-neoimplanted group in the age at diagnosis (10.5 vs. < 1 months), higher degrees of hydronephrosis on average, a more distinct dilatation of the ureter as well as renographically significant obstruction. Children of the non-UNC group, including four children with a type B drainage curve (O'Reilly), had an unimpaired differential renal function or improved during the observation period (initially 51% vs. 50.5% at the end). In neoimplantation group the differential function improved from 32.5% to 38.5% (p < 0.05) and obstruction resolved with one exception. CONCLUSION: Given a higher-grade PMU with a reduced function of the kidneys and a significant impaired drainage pattern and/or symptoms, neoimplantation without temporary diversion has proved to be an efficient renoprotective method. Furthermore, data clearly justify a conservative approach without urinary diversion in infants with large asymptomatic PMU.

Child↗
PubMed2006

Clinical insights into paraneoplastic cerebellar degeneration.

Neuroimaging is usually unremarkable in paraneoplastic cerebellar degeneration (PCD), at least in the early stages of the disease. A patient with proven PCD is reported in whom it could be shown that cerebellar atrophy evolved very rapidly and was present in early imaging studies. Even with the use of the whole spectrum of modern diagnostic tools, the underlying malignancy can be difficult to diagnose. In addition to mammography, MRI is recommended in these cases and repeat FDG-PET may be necessary.

Adult↗
PubMed2005

[Is 18F-FDG-PET suitable for therapy monitoring after palliative photodynamic therapy of non-resectable hilar cholangiocarcinoma?].

BACKGROUND: If existing biliary drainage is insufficient, photodynamic therapy (PDT, laser treatment after application of a photosensitizer) is an already established adjunct to palliative therapy for progressing hilar cholangiocarcinoma (Klatskin tumours), since it prolongs survival and improves quality of life. Experimental studies of other tumour entities showed that (18)F-FDG-PET ( (18)F-fluorodeosxyglucose-positron emission tomography) may play a role in monitoring tumour response to PDT. Furthermore, previous studies have revealed a high accuracy of this method for the detection of hilar cholangiocarcinoma. Therefore, the aim of the present study was to investigate the feasibility of (18)F-FDG-PET as a follow-up screening method in patients with hilar cholangiocarcinoma who underwent PDT. PATIENTS AND METHODS: 10 patients were examined by (18)F-FDG-PET before and 4 - 6 weeks after PDT. The following parameters were evaluated: maximum and mean SUV in the tumour, the ratio of maximum SUV in the tumour and mean SUV in the liver, the vital tumour volume, as well as bilirubin and CA 19 - 9 levels. RESULTS: All tumours were detected by (18)F-FDG-PET. Within a period of 4 - 6 weeks after PDT the cholestasis parameter bilirubin decreased significantly. However, SUV-associated parameters did not show a significant change after treatment while the estimated vital tumour volume even increased. DISCUSSION: PDT does not effect a relevant reduction of tumour mass in non-resectable hilar cholangiocarcinoma. However, PDT leads to a significant reduction of cholestasis. If (18)F-FDG-PET is suitable for monitoring the effect of new palliative therapeutic approaches, like brachytherapy, the use of modern chemotherapeuticals, COX-2 and receptor-tyrosine kinase inhibitors, perhaps also in combination with PDT, has to be further investigated.

Bile Duct Neoplasms↗
PubMed2004

Differential hepatic gene expression in a polygenic mouse model with insulin resistance and hyperglycemia: evidence for a combined transcriptional dysregulation of gluconeogenesis and fatty acid synthesis.

New Zealand obese (NZO) mice exhibit severe insulin resistance of hepatic glucose metabolism. In order to define its biochemical basis, we studied the differential expression of genes involved in hepatic glucose and lipid metabolism by microarray analysis. NZOxF1 (SJLxNZO) backcross mice were generated in order to obtain populations with heterogeneous metabolism but comparable genetic background. In these backcross mice, groups of controls (normoglycemic/normoinsulinemic), insulin-resistant (normoglycemic/hyperinsulinemic) and diabetic (hyperglycemic/hypoinsulinemic) mice were identified. At 22 weeks, mRNA was isolated from liver, converted to cDNA, and used for screening of two types of cDNA arrays (high-density filter arrays and Affymetrix oligonucleotide microarrays). Differential gene expression was ascertained and assessed by Northern blotting. The data indicate that hyperinsulinemia in the NZO mouse is associated with: (i) increased mRNA levels of enzymes involved in lipid synthesis (fatty acid synthase, malic enzyme, stearoyl-CoA desaturase) or fatty acid oxidation (cytochrome P450 4A14, ketoacyl-CoA thiolase, acyl-CoA oxidase), (ii) induction of the key glycolytic enzyme pyruvate kinase, and (iii) increased mRNA levels of the gluconeogenic enzyme phosphoenolpyruvate carboxykinase. These effects were enhanced by a high-fat diet. In conclusion, the pattern of gene expression in insulin-resistant NZO mice appears to reflect a dissociation of the effects of insulin on genes involved in glucose and lipid metabolism. The data are consistent with a hypothetical scenario in which an insulin-resistant hepatic glucose production produces hyperinsulinemia, and an enhanced insulin- and substrate-driven lipogenesis further aggravates the deleterious insulin resistance of glucose metabolism.

Animals↗
PubMed2003

Regional serotonin transporter availability and depression are correlated in Wilson's disease.

In patients with Wilson's disease (WD), depression is a frequent psychiatric symptom. In vivo neuroimaging studies suggest that depression and other neuropsychiatric disorders are associated with central serotonergic deficits. However, in vivo measurements of serotonergic neurotransmission have not until now been performed in patients with this copper deposition disorder. The present prospective study revealed that depressive symptomatology is related to an alteration of presynaptic serotonin transporters (SERT) availability as measured by [123I]-2beta-carbomethoxy-3beta-(iodophenyl)tropane ([123I]beta-CIT) and high-resolution single-photon emission computed tomography (SPECT). SERT imaging with [123I]beta-CIT-SPECT could therefore become a useful tool for diagnosis and therapy monitoring in depressed WD patients.

Adult↗
PubMed2003

Importance of F18-fluorodeoxy-D-2-glucose positron emission tomography (FDG-PET) for staging and therapy control of Hodgkin's lymphoma in childhood and adolescence - consequences for the GPOH-HD 2003 protocol.

The prognosis for children and adolescents with Hodgkin's lymphoma is excellent. However, many patients will show secondary malignancies 15-30 years after the initial diagnosis, which appears to be connected with the intensity of treatment during primary disease. In the GPOH-HD 95 trial, the indication for radiotherapy was limited to patients who did not show a complete remission after chemotherapy, as determined radiographically. In the future protocol, the indication for radiotherapy in patients with early-stage Hodgkin's lymphoma should be further refined by using FDG-PET for evaluating the response to chemotherapy. Furthermore, in patients at an advanced stage of the disease, it should be determined if sequential FDG-PET research during chemotherapy can separate patients into subgroups with an excellent or a poor prognosis. This article gives a review of the current literature on FDG-PET in patients with Hodgkin's lymphoma and outlines the consequences for future protocols.

Adolescent↗
PubMed2002

Characterisation of the mouse diabetes susceptibilty locus Nidd/SJL: islet cell destruction, interaction with the obesity QTL Nob1, and effect of dietary fat.

AIMS/HYPOTHESIS: The diabetes susceptibility locus Nidd/SJL was identified in an outcross of New Zealand obese (NZO) and lean Swiss/Jackson Laboratory mouse strain (SJL) mice. Here we characterise its effects in a NZO x F1(SJLxNZO) backcross population raised on high-fat or standard diet, and describe its interaction with the obesity quantitative trait locus (QTL) Nob1. METHODS: NZO x F1(SJLxNZO) backcross mice were raised on a normal or high fat diet and were monitored (body weight, blood glucose, serum insulin) for 22 weeks. Genotypes of polymorphic markers were determined by PCR, and linkage analysis was done. Pancreas morphology was assessed by conventional staining and immunohistochemistry of insulin. RESULTS: In backcross mice raised on a high-fat diet, Nidd/SJL produced hyperglycaemia (maximum likelihood of the odds (LOD) score 9.9), hypoinsulinaemia, reduction of islet-cell volume, and loss of beta cells. No effect was observed on body weight and serum insulin concentrations before the onset of hyperglycaemia. The development of diabetes in carriers of Nidd/SJL was markedly accelerated and aggravated by the obesity/hyperinsulinaemia QTL Nob1; together, these loci were responsible for approximately 90% of the diabetes observed in the backcross population. When raised on a standard diet, Nidd/SJL carriers exhibited a fivefold higher prevalence of diabetes, but Nob1 failed to enhance the effect of Nidd/SJL. CONCLUSION/INTERPRETATION: Diabetes in this obese mouse model is the result of an interaction of genes responsible for obesity/insulin resistance (e.g. Nob1) and islet cell failure ( Nidd/SJL). The combined diabetogenic effects of Nidd/SJL and Nob1 were markedly enhanced by a high-fat diet, whereas that of Nidd/SJL alone was independent of the dietary fat content.

Animals↗
PubMed2002

Inhibition of the renin-angiotensin system ameliorates genetically determined hyperinsulinemia.

This study was performed in order to assess the potentially different effects of the angiotensin-converting enzyme inhibitor captopril and of the angiotensin II receptor antagonist irbesartan on the metabolic syndrome in an animal model. Male NZO/BL6 F1 mice were treated with captopril, irbesartan, or placebo for 10 months: Control animals treated with placebo developed a metabolic syndrome with obesity (55.5+/-6.3 g), hypertension (146+/-10 mm Hg), hyperinsulinemia (7.2+/-5.7 ng/ml), hypercholesterolemia (5.1+/-0.7 mmol/l), cardiac hypertrophy (269+/-44 mg) and atherosclerotic plaques in the ascending aorta (3.6+/-1.5 microm(2)). Treatment with angiotensin-converting enzyme inhibitor or angiotensin II receptor antagonist significantly (p<0.001) reduces hypertension (73+/-5 and 78+/-11 mm Hg), cardiac hypertrophy (203+/-26 and 202+/-18 mg) and atherosclerosis (2.2+/-0.9 and 1.8+/-0.8 microm(2)). In addition, they prevented the development of obesity (42.2+/-3.5 and 38.3+/-2.8 g) and hyperinsulinemia (3.6+/-1.5 and 1.8+/-0.4 ng/ml). In conclusion, long-term treatment with an angiotensin-converting enzyme inhibitor or an angiotensin II receptor antagonist can ameliorate obesity and hyperinsulinemia in a genetically determined mouse model.

Angiotensin Receptor Antagonists↗
PubMed2002

Embryonic lethality caused by apoptosis during gastrulation in mice lacking the gene of the ADP-ribosylation factor-related protein 1.

ADP-ribosylation factor (ARF)-related protein 1 (ARFRP1) is a membrane-associated GTPase with significant similarity to the family of ARFs. We have recently shown that ARFRP1 interacts with the Sec7 domain of the ARF-specific guanine nucleotide exchange factor Sec7-1/cytohesin and inhibits the ARF/Sec7-dependent activation of phospholipase D in a GTP-dependent manner. In order to further analyze the function of ARFRP1, we cloned the mouse Arfrp1 gene and generated Arfrp1 null-mutant mice by gene targeting in embryonic stem cells. Heterozygous Arfrp1 mutants developed normally, whereas homozygosity for the mutant allele led to embryonic lethality. Cultured homozygous Arfrp1 null-mutant blastocysts were indistinguishable from wild-type blastocysts. In vivo, they implanted and formed egg cylinder stage embryos that appeared normal until day 5. Between embryonic days 6 and 7, however, apoptotic cell death of epiblast cells occurred in the embryonic ectoderm during gastrulation, as was shown by histological analysis combined with terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling. Epiblast cells that would normally differentiate to mesodermal cells detached from the ectodermal cell layer and were dispersed into the proamniotic cavity. In contrast, the development of extraembryonic structures appeared unaffected. Our results demonstrate that ARFRP1 is necessary for early embryonic development during gastrulation.

ADP-Ribosylation Factors↗
PubMed2002

Reduced sperm count and normal fertility in male mice with targeted disruption of the ADP-ribosylation factor-like 4 (Arl4) gene.

The ADP-ribosylation factor-like protein 4 (ARL4) is a 22-kDa GTP-binding protein which is abundant in testes of pubertal and adult rodents but absent in testes from prepubertal animals. During testis development, ARL4 expression starts at day 16 when the spermatogenesis proceeds to the late pachytene. In the adult testis, the ARL4 protein was detected in pre- and postmeiotic cells, spermatocytes, and spermatides, but not in spermatogonia and mature spermatozoa. Mouse Arl4-null mutants generated by targeted disruption of the Arl4 gene were viable and grew normally; male as well as female Arl4(-/-) mice were fertile. However, inactivation of the Arl4 gene resulted in a significant reduction of testis weight and sperm count by 30 and 60%, respectively, without reduction of litter size or frequency. It is suggested that the disruption of Arl4 produces a moderate retardation of germ cell development, possibly at the stage of meiosis.

ADP-Ribosylation Factors↗
PubMed2001

[Expert assessment of medical malpractice].

Conciliation boards are advisory commissions of the medical societies. They deal with clarification of extrajudicial patient claims based on factual or putative treatment mistakes. In perhaps 90% of the cases, an extrajudicial solution is possible, whereby the federal average for recognition is 30%. Within the framework of this study, first the legal basis for the liability of doctors is explained, especially the importance of patient information and consent as well as the responsibility for documentation. The material of the conciliation board of the medical society of Saxony consists of 1375 medical expert opinions rendered between 1 January 1992 and 23 September 2000, of which 165 cases were due to orthopedic treatment. The most common health injuries resulting in compensation claims are described.

Expert Testimony↗
PubMed2001

Differential alteration of the nigrostriatal dopaminergic system in Wilson's disease investigated with [123I]ss-CIT and high-resolution SPET.

Wilson's disease (WD) is a copper deposition disorder which can result in a number of extrapyramidal motoric symptoms such as parkinsonism. Therefore, this study was carried out to investigate, for the first time, nigrostriatal dopaminergic function in WD in relation to different courses and severity of the disease. Using high-resolution single-photon emission tomography (SPET) after administration of 2ss-carbomethoxy-3ss-(4[123I]iodophenyl)tropane ([123I]ss-CIT), striatal dopamine transporters (DAT) were imaged in 43 WD patients and a control group of ten subjects. From the SPET images, specific [123I]ss-CIT binding ratios were obtained for the caudate heads, putamina and entire corpus striatum. In addition, to evaluate a putative dissociation between the caudate and putaminal [123I]ss-CIT binding ratios, the ratio between these binding ratios was calculated (CA/PU ratio). The SPET data were compared with clinical data on the course of the disease (CD), the severity of neurological symptoms and the degree of hepatic alteration. Whereas the specific regional [123I]ss-CIT binding ratios in patients with asymptomatic/hepatic CD did not differ from those in the control group (e.g. striatal ratios: 13.4+/-3.0 vs 11.7+/-2.8), in patients with neurological CD the ratios were significantly reduced for all striatal substructures (P=0.003 after one-factor ANOVA). For the different subgroups a tendency was detected towards a stepwise decrease in the specific [123I]ss-CIT binding ratios from pseudo-sclerosis CD (9.4+/-2.3), through pseudo-parkinsonian CD (9.1+/-2.1) to arrhythmic-hyperkinetic CD (8.5+/-1.6). However, these group differences reached significance only for the comparison with asymptomatic/hepatic CD (P=0.02). The CA/PU ratio was significantly higher in WD than in the control group (1.30+/-0.19 vs 1.11+/-0.08; P=0.003). Severity of neurological symptoms was significantly correlated with all specific regional [123I]ss-CIT binding ratios (r=-0.49 to -0.57). For degree of liver alteration, significant correlations were obtained with the putaminal binding ratio (r=-0.37) and the CA/PU ratio (r=0.44). From these results is concluded that in WD the nigrostriatal dopaminergic function is compromised to varying extents. The degree of this presynaptic alteration of dopaminergic neurotransmission depends on the clinical course and severity of this copper deposition brain disorder and also varies in the different striatal substructures.

Adult↗
PubMed2001

Transmyocardial laser revascularization with the holmium:YAG laser: loss of symptomatic improvement after 2 years.

OBJECTIVE: Whether transmyocardial laser revascularization (TMLR) provides a long-term benefit in terms of relief of angina, improvement of exercise tolerance, left ventricular function, and myocardial perfusion. METHODS: Forty-one patients underwent TMLR using a holmium:YAG-laser, 14 as TMLR alone (group A), 27 with additional aortocoronary bypass grafting (group B). Follow-up was obtained at 6, 12, 18, 24, and 36 months in this prospective study. RESULTS: In group A patients CCS-class improved up to 18 months postoperatively, after 24 and 36 months postoperatively there was absence of a positive effect of TMLR: the CCS-class decreased to 2.4 as compared to 3.5 preoperatively After combined CABG and TMLR (group B) there was a significant decrease in angina at all times. The CCS-functional class in these patients was 1.7 at 36 months as compared to 3.5 preoperatively. There was no significant change in exercise tolerance as compared to preoperatively. Left ventricular ejection fraction did not improve in either of the groups. Thallium scintigraphy indicated no improvement in myocardial perfusion in laser treated areas. The perioperative mortality was 0%, the late mortality rate was 36% in group A and 11% in group B. CONCLUSIONS: In our experience, in the vast majority of patients who are subjected to TMLR alone the benefit of reduction or relief of angina and improvement in quality of life is only temporary. In addition there is no improvement in objective clinical parameters. We believe that TMLR should only be used in patients with severe angina refractory to medical treatment and requiring a symptomatic therapy.

Aged↗
PubMed2001

Positron emission tomography with [(18)F]fluoro-2-deoxy-D-glucose for diagnosis and staging of bile duct cancer.

Malignant tumors with high glucose metabolic rates accumulate [18F]-fluorodeoxyglucose (FDG), a positron emitting tracer. The aim of this study was to evaluate FDG positron emission tomography (PET) for detection and staging of human cholangiocarcinoma (CC). Patients with adenocarcinoma of the biliary tree (n = 26), with benign lesions of the bile ducts (n = 8), and 20 control patients underwent FDG-PET (370 MBq [18F]-FDG, Siemens ECAT EXACT HR(+)). In a blinded fashion, 4 independent experts evaluated the PET scans visually and semiquantitatively using the standardized uptake value and a tumor/non-tumor ratio. All adenocarcinomas and benign lesions (sclerosing cholangitis, bile duct adenoma, Caroli's disease) were histologically proven and imaged by magnetic resonance imaging and endoscopic retrograde cholangioscopy. True-positive PET scans were obtained in 24 of 26 CC and false-negative scans in the other 2 (sensitivity 92.3%). The PET scan was true-negative in 18 of 20 controls and in all 8 benign biliary lesions (specificity 92.9%). Visual and semiquantitative evaluation using tumor/non-tumor ratios were equally accurate (accuracy 92.6%) whereas evaluation by standardized uptake value revealed lower accuracy (P <.05). Regional or hepatoduodenal lymph node metastases were detected with PET in only 2 of 15 cases whereas distant metastases (peritoneal carcinomatosis, pulmonary metastases) were diagnosed in 7 of 10 cases. In conclusion, PET is highly sensitive and specific for the detection and localization of CC. It can be helpful for diagnosis of distant metastases but is not suitable for detection of regional lymph node metastases.

Adenocarcinoma↗
PubMed2001

[18F-FDG positron-emission-tomography in cervical carcinoma: preliminary findings].

18F-Fluorodesoxyglucose-Positron-Emission-Tomography (18F-FDG-PET) is a novel imaging modality for malignancies. This study was initiated to define the efficiency of PET in detecting and characterizing metabolically the primaries and in preoperatively assessing of lymphonodal metastases of cervical cancer. 15 patients with histologically proven cervical carcinoma were studied with 18F-FDG-PET regarding 18F-FDG-uptake of primary tumor and evidence as well as extent of lymphonodal metastases. 18F-FDG-PET and histopathological results were compared after radical hysterectomy with pelvic and supplementary in 7 cases paraaortal lymphadenectomy. All primary tumours showed 18F-FDG accumulation and had a mean maximal standardized uptake value (SUV) of 8.0 +/- 5.3. 3/6 lymph node metastases were obtained with 18F-FDG-PET. Micrometastases (size of metastasis < or = 0.2 cm) were present in 2 patients with false negative PET results. Regarding the subgroup with paraaortal lymph node dissection, PET detected one patient with metastases, the other one had micrometastasis, while metastasis was not observed by PET. The accuracy of PET is 73% for assessment of pelvic lymph nodes and 86% for assessment of paraaortal lymph nodes. In conclusion 18F-FDG accumulates reliably in primaries of cervical cancer. Regarding assessment of lymph node metastases PET seems to be of potential use, offering metabolic information independent of the size of metastatic lymph nodes. An improvement of accuracy can be expected if combined evaluation of morphologic and metabolic images is performed.

Adult↗