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Biomedical subjects

A Koch

Publications and source records attributed to A Koch.

At least 91 records · Page 5Linked to original sources
PubMed2001

Plastidic (Pho1-type) phosphorylase isoforms in potato (Solanum tuberosum L.) plants: expression analysis and immunochemical characterization.

Higher plants contain two types of phosphorylase (EC 2.4.1.1). One type is plastidic (Phol) and the other resides in the cytosol (Pho2). For Solanum tuberosum L., two highly homologous Pho1-type sequences (designated as Pho1a and Pho1b, respectively) have been described that occur both in a homodimeric, (Pho1a)2, and a heterodimeric, Pho1a-Pho1b, state [U. Sonnewald et al. (1995) Plant Mol Biol 27:567 576; T. Albrecht et al. (1998) Eur J Biochem 251:981-991]. We present a spatial and temporal analysis of the expression patterns of the Pho1-type phosphorylases in S. tuberosum. Expression was analyzed at transcript, protein and activity levels. The specificity of both the probes and the antibodies used was carefully determined to ensure selectivity of detection. For both the Pho1a and Pho1b probes the degree of cross-hybridization was estimated. Peptide scanning identified the epitopes of the anti-Pho 1a and anti-Pho 1b antibodies. Expression of the two Pho1-type genes was analyzed in various organs of the potato plant. In all organs studied the Pho1a transcript levels exceeded those of Pho1b. Furthermore, leaves of a given developmental stage were sampled during the light period and were analyzed for transcript and protein levels and for various carbohydrate pools as well. The data show that in leaves the Pho1a gene expression closely corresponds to starch accumulation, suggesting that the enzyme fulfils a metabolic function within the process of starch biosynthesis. In tubers, Pho1a is constitutively expressed in the parenchyma cells whereas expression of the Pho1b, gene is restricted to cells in close vicinity of the vascular tissue.

Amino Acid Sequence↗
PubMed2001

Promoter-specific transcription of the IGF2 gene: a novel rapid, non-radioactive and highly sensitive protocol for mRNA analysis.

The human insulin-like growth factor-II (IGF2) is a regulatory peptide which is critical in normal fetal growth. IGF2 gene transcription is controlled by the usage of four promoters P1-P4 of which promoters P2-P4 are genomically imprinted. Disruption of imprinting and the resulting increase of gene dosage have been shown to be implicated in tumor progression in a variety of human tumors. Due to the need for high amounts of tissue material for conventional methods such as Northern blotting or ribonuclease protection assay (RPA), studies on IGF2 expression have most often been limited to the detection of total IGF2 transcript, though different dysregulatory events can be responsible for the abundance of IGF2 mRNA found in many tumors. We established a highly sensitive competitive RT-PCR assay for the four different transcripts of the IGF2 gene with transcript-specific external RNA competitors in which we take advantage of fluorescence-based quantification on a semiautomated sequencer. The amount of total RNA needed is approximately 100 times lower than the amounts required for Northern blotting or RPA, so that even cytological samples can be analyzed. We applied the assay to a series of eleven hepatoblastomas (HB) in which normal adjacent liver tissue could also be analyzed.

Child, Preschool↗
PubMed2001

Bacterial release of arsenic ions and organoarsenic compounds from soil contaminated by chemical warfare agents.

The objective of this paper was to investigate possible participation of microorganisms in the release of soluble arsenical compounds from organoarsenic warfare agents in contaminated soil. A number of bacterial strains were isolated with high resistance against As3+ and As5+ ions which are able to degrade the water insoluble compounds triphenylarsine (TP) and triphenylarsineoxide (TPO). These strains belong to different genera of bacteria. Release of arsenic ions and soluble organoarsenic compounds from soil by the activity of autochthonic soil bacteria and a mixture of the isolated pure cultures was demonstrated by percolation experiments with undisturbed soil samples (core drills) from the contaminated site. This release increased after addition of nutrients (mineral nitrogen and phosphorus, sodium acetate and ethanol) and is nearly independent of the percolation temperature (5 degrees C and 22 degrees C). These results show that bacteria play an important role in the release of arsenical compounds from organoarsenic warfare agent contaminated soil. This release is limited by shortage of water and, above all, of nutrients for the microorganisms in the sandy forest soil. These results are important both for the management and security and possibly for bioremediation of military waste sites containing similar contaminations. Furthermore, this is the first report on bacterial degradation of organoarsenic warfare compounds.

Arsenicals↗
PubMed2001

Regulation of matrix metalloproteinases and their inhibitors in uterine endometrial cells of patients with and without endometriosis.

OBJECTIVE: To determine whether alterations in the secretion and regulation of matrix metalloproteinases (MMPs) and their inhibitors are present in uterine endometrial cells from endometriosis patients. STUDY DESIGN: In an in vitro study, uterine endometrial cells from 19 regularly cycling women with and 32 without endometriosis were treated with diethyl stilbestrol, promegestone (R5020), interleukin-1 (IL-1) and tumor necrosis factor a (TNF-alpha). Culture supernatants were assayed for MMPs 1, 2, 3, and 9, and for tissue inhibitors of MMP (TIMP-1 and TIMP-2) by ELISA. RESULTS: MMP-3 was secreted in high concentrations, moderate concentrations were seen for MMP-1 and MMP-2, and very low concentrations for MMP-9. Substantially more TIMP-1 than TIMP-2 was secreted. MMP-1 and MMP-3 were uniformly attenuated by R5020, while MMP-2 was not influenced by hormone treatment. MMP-3 was upregulated by TNF-alpha in all samples while IL-1 only increased secretion in cells from endometriosis patients. CONCLUSION: The upregulation of MMP-3 by IL-1 may contribute to an increased invasiveness of uterine endometrial fragments in endometriosis patients.

Adult↗
PubMed2001

Capillary endothelia and cardiomyocytes differ in vulnerability to ischemia/reperfusion during clinical heart transplantation.

OBJECTIVE: The development of accelerated graft arteriosclerosis is a major cause of late death after orthotopic heart transplantation. The influence and the extent of peritransplant injury, especially of cardiomyocyte or capillary endothelial cell edema is discussed. METHODS: A morphometric ultrastructural analysis of myocardial biopsies from 29 donor hearts (21 male, age 34+/-11 years) was performed. Right ventricular biopsies were obtained before cardioplegia (A), immediately following cardioplegia (B) (Custodiol, Dr. F. Köhler Chemie GmbH, Alsbach-Hähnlein, Germany), before implantation (C), after 30 (D) or 60 (E) min of reperfusion and 1 week after transplantation (F). Mean ischemic time was 185+/-68 min. Quantitative electron microscopy was carried out in five samples per heart and time point and in 30 test fields per sample by 'random systematic sampling' and 'point and intersection counting'. As parameters for cell edema the volume density of myofibrils in cardiomyocytes and the mean barrier thickness of capillary endothelia were analyzed. P-values of less than 0.05 were regarded as significant. Significant differences in contrast to the previous values are marked by *. RESULTS: The volume density of myofibrils (vol.%) was as follows: (B) 63.6+/-3.2, (C) 61.8+/-3.2, (D) 62.9+/-3.2, (E) 63.6+/-4.5. The mean barrier thickness (nm) was as follows: (A) 353+/-21, (B) 376+/-59, (C) 416+/-71*, (D) 473+/-45*; (E) 453+/-50*, (F) 379+/-39. CONCLUSIONS: Apart from a generally accepted edema of cardiomyocytes a relevant capillary endothelial cell edema develops during clinical heart transplantation. In contrast to cardiomyocytes the cell edema of endothelia shows a more pronounced and significant progression during cold ischemia and early reperfusion. After 60 min of reperfusion it is still significantly more pronounced than at the onset of ischemia. After 1 week there are no statistical differences compared to the initial values. Thus, an edema of capillary endothelia probably will trigger inhomogeneities in capillary perfusion. Peritransplant injury of endothelia may contribute to the later development of accelerated allograft arteriosclerosis.

Adult↗
PubMed2001

Hospital caseload and the results achieved in patients with rectal cancer.

BACKGROUND: The aim of the study was to investigate the impact of hospital caseload on the short-term postoperative outcome of patients with rectal carcinoma. METHODS: A multicentre study involving 75 German hospitals was carried out between January and December 1999. Some 1463 patients with rectal carcinoma were studied. RESULTS: The hospitals were divided into three groups by annual caseload as follows: less than 20 (group 1), 20-40 (group 2) and more than 40 (group 3). The groups were identical in terms of age, gender, height, weight, tumour stage, risk factors and American Society of Anesthesiologists classification. Postoperative morbidity was less in hospitals with a case volume of more than 20 patients per year (41.7 per cent in group 2 versus 49.9 per cent in group 1). The proportion of patients undergoing abdominoperineal resection with a permanent stoma was less in hospitals with a case volume of more than 40 patients per year (26.4 per cent in group 3 versus 34.0 per cent in group 2). CONCLUSION: A large caseload in rectal surgery results in a significant reduction in permanent stoma formation and postoperative morbidity.

Anastomosis, Surgical↗
PubMed2001

Pets and vermin are associated with high endotoxin levels in house dust.

BACKGROUND: Previous studies have shown that the risk for allergic sensitization is lower in children who grew up on farms and in young adults who were exposed to dogs in early childhood. A higher microbial exposure in general and in particular to endotoxin in early childhood might contribute to this lower risk of atopy. OBJECTIVE: We examined whether the presence of pets or vermin in the home is associated with higher endotoxin concentrations in settled house dust. METHODS: House dust was sampled in a standardized manner on the living room floors of 454 homes of German children aged 5-10 years (participation rate 61%). Endotoxin was assessed with a quantitative kinetic chromogenic Limulus Amebocyte Lysate (LAL) method. Associations between endotoxin levels, pets and vermin are presented as ratios of the crude and confounder adjusted geometric means (means ratios) in the category of study vs. a reference category using multiple linear regression models. RESULTS: Endotoxin concentrations in living room floor dust sampled in homes without pets and vermin were lower (1246 ng per square meter, 1519 ng endotoxin/g dust, n = 157) than those sampled in homes with pets or vermin (2267 ng per square meter, 2200 ng endotoxin/g dust, n = 296). After adjustment for city of residence, season of dust sampling, age of the building and story of the dwelling, means ratios for endotoxin expressed per gram of dust were statistically significantly increased for dog (1.64, 95% CI 1.09-2.46), for cat (1.50, 95% CI 1.03-2.18) and for cockroach (3.01, 95% CI 1.37-6.60), whereas no major statistically significant associations were found for other pets, ants and mice. CONCLUSION: Keeping a dog or a cat in the home is consistent with higher exposure to endotoxin and might therefore contribute to the lower risk of atopy in later life.

Air Pollution, Indoor↗
PubMed2001

The humoral immune response to recombinant nucleocapsid antigen of canine distemper virus in dogs vaccinated with attenuated distemper virus or DNA encoding the nucleocapsid of wild-type virus.

This study compared the humoral immune response against the nucleocapsid-(N) protein of canine distemper virus (CDV) of dogs vaccinated with a multivalent vaccine against parvo-, adeno-, and parainfluenza virus and leptospira combined with either the attenuated CDV Onderstepoort strain (n = 15) or an expression plasmid containing the N-gene of CDV (n = 30). The vaccinations were applied intramuscularly three times at 2-week intervals beginning at the age of 6 weeks. None of the pre-immune sera recognized the recombinant N-protein, confirming the lack of maternal antibodies at this age. Immunization with DNA vaccine for CDV resulted in positive serum N-specific IgG response. However, their IgG (and IgA) titres were lower than those of CDV-vaccinated dogs. Likewise, DNA-vaccinated dogs did not show an IgM peak. There was no increase in N-specific serum IgE titres in either group. Serum titres to the other multivalent vaccine components were similar in both groups.

Animals↗
PubMed2001

Glomerulosclerosis and progression: effect of subantihypertensive doses of alpha and beta blockers.

BACKGROUND: Uremia is characterized by inadequately increased sympathetic activity. Sympathetic overactivity is involved in the genesis of hypertension in uremia, but its potential role on progression has not been well investigated. To address this issue, the effect of subantihypertensive doses of an alpha blocker and a beta blocker, and their combination on renal morphology and on albuminuria were investigated in the model of the subtotally nephrectomized rat. METHODS: Male Sprague-Dawley rats were subjected to surgical ablation (SNX) or sham operation (sham). Three days after surgery groups were treated either with phenoxybenzamine (PBZ, 5 mg/kg body weight/day), metoprolol (MET, 150 mg/kg body weight/day) or their combination (PBZ 2.5 mg/kg body weight/day + MET, 50 mg/kg body weight/day). Renal morphology was evaluated after 12 weeks by quantitative histology, immunohistochemistry, and electron microscopy. Urine albumin excretion and kidney endothelin-1 (ET-1), platelet-derived growth factor (PDGF), and transforming growth factor-beta (TGF-beta) mRNA expression were assessed. RESULTS: Systolic blood pressure was significantly higher in all SNX groups compared with sham-operated controls with no difference in the SNX groups. The number of glomeruli per left kidney was reduced from 30,904 +/- 3212 to 17,480 +/- 2341 by SNX (-43.5%). Mean glomerular volume increased from 2.63 +/- 0.7 in untreated sham operated to 4.11 +/- 0.48 microm 3 x 10(6) in untreated SNX (56.3%). The glomerulosclerosis index did not change in SNX + PBZ rats, but was significantly lower in SNX + MET (0.56 +/- 0.14) and particularly SNX + PBZ + MET rats (0.49 +/- 0.11) than in untreated SNX (0.74 +/- 0.24). Glomerular capillary length density (LV) as a sensitive index of capillary obliteration was significantly lower in SNX and almost normalized in the three intervention groups. The same was true for the mean podocyte number per glomerulus. Glomerular ultrastructure in SNX was largely preserved by all treatments. The albumin excretion rate was significantly higher in untreated SNX than in sham; it was significantly lower in all treated SNX groups. CONCLUSION: The beneficial effect of non-hypotensive doses of alpha and beta blockers and their combination on renal morphology and albuminuria in the model of renal ablation argue for a blood pressure-independent role of sympathetic overactivity in the genesis of progression. In addition, the beneficial effect of adrenergic receptor blockade indicates that a substantial part is not mediated by sympathetic cotransmitters such as adenosine 5'-triphosphate (ATP) and neuropeptide Y (NPY).

Adrenergic alpha-Antagonists↗
PubMed2001

Antigenicity of polyester (Dacron) vascular prostheses in an animal model.

Objectives to investigate the specific humoral immune response to three different polyester (Dacron) prostheses in pigs. Design, materials and methods twenty-four growing pigs were randomly divided into three groups. The infrarenal aorta was replaced by a segment of collagen-impregnated woven polyester prosthesis (low, medium and high porosity). Serum antibodies were detected by modified enzyme immunoassay using non-impregnated prosthesis as the target for the blood samples taken on experimental days 1, 10, 17, 24, 62 and 116 of the 22 pigs followed over the whole observation period. Results significantly enhanced (p <0.05) mean IgG antibody binding against polyester was detected on experimental days 10, 17, 24 and 62 with antibody prevalences of 41%, 41%, 32% and 37%, respectively. Antibody positive pigs were divided into early responders (n =9) and late responders ( n =5) with antibody detection on day 10 and/or 17 vs day 62 and/or 116. No significant differences between the three different prostheses were found. The formation of specific IgG antibodies against polyester in the animals investigated demonstrates a broad individual variability. Conclusions polyester is an antigenic polymer. Specific antibodies, reflecting the inflammatory response, might be not only a parameter for testing biomaterials but also for determining individual bio(in)compatibility for long-term biomaterial function.

Animals↗
PubMed2001

[Simultaneous transthoracic echocardiography and transcranial doppler ultrasonography with ultrasound contrast agents for the detection of a patent foramen ovale in diving medicine].

OBJECTIVE: Presentation of a non-invasive method for the identification of a patent foramen ovale (PFO) in screening of diving-candidates or for the investigation of diving accidents. METHOD: Simultaneous transthoracic echocardiography and transcranial Doppler sonography of the middle cerebral artery using ultrasound contrast media. RESULTS: In an unselected collective of amateur and professional divers a PFO was identified according to statistical prediction. CONCLUSION: This method can be used in diving medicine for PFO detection as an alternative procedure to transesophageal echocardiography.

Adult↗
PubMed2001

[Management of a deaf-blind patient with a 12-channel cochlear implant].

A case study of a deaf-blind patient implanted with the COMBI40+ cochlear implant is presented. The patient is a 70-year-old woman who has been blind since the age of 40. Since 1977 the hearing loss continuously increased. Before surgery she had a very small residual hearing (with hearing aid: 40% speech intelligibility by four syllable numbers) and she used Braille and finger-spelling on her hand to communicate with other people. The patient has a high intelligence and so she did not have any problems when the speechprocessor was fitted and during the hearing therapy. After one month she had an open-set-speech recognition. The quality of her life is much better than before surgery. The communication by finger-spelling on her hand is not necessary any longer.

Aged↗
PubMed2001

[Singular late metastasis of renal cell carcinoma in the pancreas. An unusual pancreatic tumor].

We present the rare case of a solitary pancreatic metastasis of renal cell cancer being the only manifestation of tumordissemination. In 1993 the patient underwent a transperitoneal nephrectomy for removal of a clear cell renal cancer. In 1998 during follow up we detected a pancreatic tumor which was treated by pancreas resection, splenectomy and resection of the colon transversum. The histology revealed a metastasis of the previously resected renal cancer. The postoperative recovery was impaired by the development of an abcess in the former pancreatic region. During the first year of follow up we did not find any signs for local or distant tumor recurrence. Pancreas resection adapted to the location of the tumor is the treatment of choice for isolated solitary late metastases of renal cell cancer.

Carcinoma, Renal Cell↗
PubMed2001

[Echocardiographic findings before and after interventional occlusion of persistently patent ductus arteriosus with the amplatzer duct occluder].

AIM: The Amplatzer duct occluder(R) is a new system for interventional occlusion of persistently patent ductus arteriosus. The purpose of our study was to determine, whether adequate evaluation of this occluder system can be obtained by echocardiography. METHOD: From 11/1999 until 12/2000, 18 patients were included in the study. All underwent interventional occlusion of a patent ductus arteriosus with the Amplatzer duct occluder(R). Echocardiography was performed on admission, on day one and three and six months following the intervention. RESULTS: The mean age of our patients was 4.8 years (9 months - 18.7 years, median 3.2 years), the mean weight was 18.4 kg (6.5 - 66 kg, median 14 kg). All echocardiographic findings prior to intervention were confirmed during cardiac catheterization. Following intervention we were able to visualize the occluder system and its relation to surrounding structures in all patients. In none of our patients we found an obstruction of the left pulmonary artery. In 1/18 patients there was a minor protrusion of the distal occluder into the descending aorta. Doppler-sonography however revealed no obstruction. Complete occlusion of the ductus arteriosus was confirmed by color Doppler echocardiography in all patients within 5 days, in 17/18 patients no residual shunt was detectable within 24 hours. CONCLUSION: According to our experience the results of interventional occlusion of patent ductus arteriosus in children and adolescents can be well determined by echocardiography.

Adolescent↗
PubMed2001

Real-time assessment of intraperitoneal tumor growth in a rat model using CEA immunoscintigraphy.

BACKGROUND: In most preclinical models, assessment of intraperitoneal tumor location and size require killing the animal. The dynamics of postoperative intraperitoneal tumor implantation and growth remain unclear. A noninvasive method allowing reliable in vivo, real-time assessment of tumor growth is desirable. METHODS: An intraperitoneal tumor homograft using cultured CC531 colorectal cells was created by laparotomy in 24 Wistar Albino Glaxo rats. Eight additional rats were used as controls. Then, 10 MBq technetium 99m-labeled anticarcinoembryonic antigen (anti-CEA) monoclonal antibodies were administrated intravenously and radioactivity uptake was measured by using extracorporeal gamma counting at various time points. Subsequently, the animals were killed for tumor weighting. In 2 more groups of 8 animals, real-time, repeated measures were performed. RESULTS: Correlation between gamma counting and tumor weight was highly significant (P <.001). The regression equation obtained by using the least squares method was: tumor weight (g) = 2.422 + 0.267 x counts. It was possible to obtain real-time tumor growth curves when repeated measurements of radioactivity were performed. At day 25, the predicted tumor weight was 8.49 +/- 0.76 g, the measured weight was 8.16 +/- 0.99 g. CONCLUSIONS: Immunoscintigraphic measurements with technetium 99m anti-CEA antibodies are highly correlated with tumor weight in this model. As opposed to other tumor graft models based on autopsy findings, real-time monitoring is possible. This will allow dynamic studies of intraperitoneal tumor implantation and growth and will reduce the number of animals used in further studies.

Animals↗
PubMed2001

Incidence and predictors of atopic dermatitis in an open birth cohort in Sisimiut, Greenland.

UNLABELLED: The frequency of atopic dermatitis (AD) is unknown among children in Greenland. To determine the incidence of AD and to identify risk factors for onset of AD within the first 2 y of life among Greenlandic children an open cohort of 143 children aged 0-2 y in Sisimiut, West Greenland, was followed for a median of 335 d. The children were visited on a weekly basis, where clinical examinations revealed any cases of AD. In total, 24 of the 143 children developed AD. The incidence rate of AD was 177 cases per 1000 child years at risk, corresponding to a cumulative risk of 16% per year. Maternal history of AD [hazard ratio (HR) 2.6, 95% confidence interval (CI) 1.03-6.57], high social class of the family (HR 6.18, CI 2.19-17.41) and living in a detached house compared with living in a terraced house or an apartment (HR 2.81, CI 1.16-6.28) were associated with increased risks of AD. In a multivariate model these risk factors all remained significant. CONCLUSION: The findings confirm that AD represents a health problem among Greenlandic infants and that the pattern of predictive risk factors associated with the development of AD is comparable to that found in northern European countries.

Child, Preschool↗
PubMed2001

Quality of life after surgical therapy of small bowel stenosis in Crohn's disease.

BACKGROUND: Improvement in quality of life is one of the important determinants in the treatment of Crohn's disease. Since there is no cure with radical resection of inflamed bowel, strictureplasty has become a useful surgical technique in the treatment of small bowel obstruction. The scope of this study was to define the results of strictureplasty and resection in terms of quality of life, surgical recurrence and postoperative complications. METHODS: The charts of 67 patients with Crohn's disease of the small bowel were analyzed retrospectively. Patients were treated either by strictureplasty (group A) or resection (group B). Quality of life was evaluated in follow-up examinations using the Inflammatory Bowel Disease Questionnaire (IBDQ). RESULTS: Postoperative morbidity was 14.8% after strictureplasty and 17% after resection (p = 0.8). 50% of the patients treated by strictureplasty and 37% treated by resection developed recurrent disease (p = 0.40). Quality-of-life measurement revealed no significant difference between patients treated by strictureplasty or resection. CONCLUSION: Results after strictureplasty are comparable to those after resection in terms of complications, recurrence and quality of life in the treatment of small bowel strictures in Crohn's disease. In the long run there might be an advantage for strictureplasty because it prevents complications caused by resectional therapy such as short bowel syndrome.

Adolescent↗