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C Gebhardt

Publications and source records attributed to C Gebhardt.

At least 73 records · Page 4Linked to original sources
PubMed1994

Segregation analysis and RFLP mapping of the R1 and R3 alleles conferring race-specific resistance to Phytophthora infestans in progeny of dihaploid potato parents.

Phytophthora infestans (Mont.) de Bary is the most important fungal pathogen of the potato (Solanum tuberosum). The introduction of major genes for resistance from the wild species S. demissum into potato cultivars is the earliest example of breeding for resistance using wild germplasm in this crop. Eleven resistance alleles (R genes) are known, differing in the recognition of corresponding avirulence alleles of the fungus. The number of R loci, their positions on the genetic map and the allelic relationships between different R variants are not known, except that the R1 locus has been mapped to potato chromosome V. The objective of this work was the further genetic analysis of different R alleles in potato. Tetraploid potato cultivars carrying R alleles were reduced to the diploid level by inducing haploid parthenogenetic development of 2n female gametes. Of the 157 isolated primary dihaploids, 7 set seeds and carried the resistance alleles R1, R3 and R10 either individually or in combinations. Independent segregation of the dominant R1 and R3 alleles was demonstrated in two F1 populations of crosses among a dihaploid clone carrying R1 plus R3 and susceptible pollinators. Distorted segregation in favour of susceptibility was found for the R3 allele in 15 of 18 F1 populations analysed, whereas the R1 allele segregated with a 1:1 ratio as expected in five F1 populations. The mode of inheritance of the R10 allele could not be deduced as only very few F1 hybrids bearing R10 were obtained. Linkage analysis in two F1 populations between R1, R3 and RFLP markers of known position on the potato RFLP maps confirmed the position of the R1 locus on chromosome V and localized the second locus, R3, to a distal position on chromosome XI.

Alleles↗
PubMed1994

Quantitative resistance to Phytophthora infestans in potato: a case study for QTL mapping in an allogamous plant species.

Phytophthora infestans is the most important fungal pathogen in the cultivated potato (Solanum tuberosum). Dominant, race-specific resistance alleles and quantitative resistance--the latter being more important for potato breeding--are found in the germplasm of cultivated and wild potato species. Quantitative trait loci (QTLs) for resistance to two races of P. infestans have been mapped in an F1 progeny of a cross between non-inbred diploid potato parents with multiple alleles. Interval mapping methods based on highly informative restriction fragment length polymorphism markers revealed 11 chromosome segments on 9 potato chromosomes showing significant contrasts between marker genotypic classes. Whereas phenotypically no difference in quantitative resistance response was observed between the two fungal races, QTL mapping identified at least one race specific QT locus. Two QT regions coincided with two small segments on chromosomes V and XII to which the dominant alleles R1, conferring race specific resistance to P. infestans, Rx1 and Rx2, both inducing extreme resistance to potato virus X, have been allocated in independent mapping experiments. Some minor QTLs were correlated with genetic loci for specific proteins related to pathogenesis, the expression of which is induced after infection with P. infestans.

Alleles↗
PubMed1994

Transcripts accumulating during cold storage of potato (Solanum tuberosum L.) tubers are sequence related to stress-responsive genes.

During the adaptation of plants to low temperature, changes in gene expression can be induced in a variety of tissues. Low-temperature-regulated gene expression was studied in cold-stored potato (Solanum tuberosum L.) tubers by two-dimensional electrophoresis of in vitro translation products. As a response to cold treatment, the relative amount of mRNA encoding at least 26 polypeptides changed. By differential screening of a cDNA library, 16 clones corresponding to cold-inducible transcripts were isolated. They were classified into four non-cross-hybridizing groups. RNA hybridizations using representative clones from each group revealed different temporal accumulation patterns for the cold-inducible transcripts. mRNAs homologous to the cDNA clones were first detectable after 1 to 3 d of cold treatment, and the highest level of expression was reached after 3 to 7 d. Transcripts corresponding to cDNA clones CI13 and CI19 were transiently expressed, whereas the steady-state level remained high for cDNA clones CI7 and CI21 during the cold storage period of 4 weeks. The DNA sequences of two cDNA clones, CI7 and CI19, have been determined. The polypeptide predicted from the DNA sequence of CI19 is sequence related to small heat-shock proteins from other plant species. The deduced protein sequence of CI7 exhibits strong homology to the dehydrin/RAB group of dehydration stress- and abscisic acid-inducible polypeptides and to cold-induced proteins from Arabidopsis and spinach.

Amino Acid Sequence↗
PubMed1994

[Lesions of the bile ducts in open cholecystectomy].

The incidence of bile duct injuries during open cholecystectomy is around 2/1000. The most common lesion is complete divisions of the common bile duct, followed by partial divisions, stenoses or obstructions. The therapy of the lesions recognized intraoperatively is end-to-end anastomosis or, in the case of greater defects, hepaticojejunostomy. Strictures manifesting while after cholecystectomy can primarily be treated endoscopically, in divisions of obstructions hepaticojejunostomy is indicated; in high lesions the Hepp-Couinaud approach can be advocated.

Anastomosis, Surgical↗
PubMed1994

[Changes in therapy of severe acute pancreatitis].

Report about the treatment of necrotizing pancreatitis in the years 1988 until 1991. A rigorous conservative therapy was preferred, so that only 8.6% of the 140 patients underwent surgery. In 11 cases a continuous venous-venous hemofiltration (CVVH) was applied to patients with most serious clinical course and multi-system failure. The overall lethality rate of all treated patients was 7.9%. The present results show, that, eliminating mediators by hemofiltration, system failure in connection with sterile necrosis can be treated with a good success rate. Therefore toxic organ failure should no longer be regarded as an imperative indication for operation. We recommend strict intensive care including CVVH and antibiotical prophylaxis for treatment of sterile necrosis, while surgical therapy should only be applied to patients with bacterial contamination of pancreatic necrosis.

Acute Disease↗
PubMed1993

[Multivisceral resection of advanced stomach cancer].

From 1985 to 1990, 589 patients with gastric cancer were operated upon. Gastric resection was performed on 416 patients (71%); it was curative in 330 cases and palliative in 86 cases. Multivisceral resection was necessary in 61 patients (i.e. 15% of the resected patients) because of distant metastases or T4 tumors (curative: 43 cases--palliative: 18 cases). Compared to the group of curative resections without multivisceral extension, the complication rate (27% vs 26%) and 30-day lethality (5.2% vs 3.3%) were similar, whereas the 5-year survival rate was lower (22% vs 48%). However, the survival rate (21%) was nearly identical for T3 tumors in the group without multivisceral extension. These results show that curative gastric resections of T4 tumors lead to the same long-term results as resections of T3 tumors and the complication rate and lethality are equal.

Aged↗
PubMed1992

The R1 gene conferring race-specific resistance to Phytophthora infestans in potato is located on potato chromosome V.

Late blight in potato is caused by the fungus Phytophthora infestans and can inflict severe damage on the potato crop. Resistance to P. infestans is either based on major dominant R genes conferring vertical, race-specific resistance or on "minor" genes inducing horizontal, unspecific resistance. A dihaploid potato line was identified which carried the R1 gene, conferring vertical resistance to all P. infestans races, with the exception of those homozygous for the recessive virulence allele of the locus V1. The F1 progeny of a cross between this resistant parent P(R1) and P(r), a line susceptible to all races, was analysed for segregation of R1 and of restriction fragment length polymorphism (RFLP) markers distributed on the potato RFLP map comprising more than 300 loci. The R1 locus was mapped to chromosome V in the interval between RFLP markers GP21 and GP179. The map position of R1 was found to be very similar to the one of Rx2, a dominant locus inducing extreme resistance to potato virus X.

Chromosomes↗
PubMed1992

[Cushing syndrome in a neuroendocrine pancreatic tumor. Clinicopathologic case report].

A 59-year-old female patient with mild clinical features of a Cushing syndrome underwent surgery for a suspected hormonally active tumor of the left adrenal gland. Surprisingly, the adrenal gland was unremarkable, however, a tumor in the pancreatic tail was found. A left pancreatic resection with splenectomy resulted in curative removal of the tumor. The pathohistological examination of the tumor established the diagnosis of an ACTH-producing pancreatic carcinoid. Morphology and pathogenesis of pancreatic carcinoids which are tumors of the APUD-cell-system are discussed in detail.

ACTH Syndrome, Ectopic↗
PubMed1992

[Thoracoscopic use of staplers. New possibilities for minimally invasive diagnosis and therapy].

Thoracoscopic resection of peripheral lung tissue is possible by using special staplers (Endo-GIA). Main indications for using this technique are the treatment of a spontaneous pneumothorax by resection of bullous lung areas (15 patients) and the excision of macro biopsies for diagnostic reasons (13 patients). It is reported about the technique and the early outcome of these 28 thoracoscopically performed lung resections. This way minimally invasive procedure is combined with well-established surgical technique.

Biopsy↗
PubMed1992

[Indication for chemoembolization of liver tumors. An interdisciplinary concept and initial results].

We present a new concept after Schultheis which is based on the results of experimental studies on cell cultures. Local chemoembolization in liver tumours including liver metastases is usually performed via the angiographic route. Embolisation of the most peripheral branches of the hepatic artery prevents early formation of collateral vessels. The method also comprises the additional infusion of cytostatic agents via the portal vein. The procedure is usually repeated after an interval of about four weeks. In this paper we will describe our method in liver metastases and present the preliminary results obtained from 19 patients treated to date.

Adult↗
PubMed1991

A randomized controlled trial of adjuvant immunotherapy (murine monoclonal antibody 494/32) in resectable pancreatic cancer.

In a prospective randomized multicentric trial, 61 patients from six hospitals with resectable pancreatic cancer were recruited between 1987 and 1989. All patients underwent a Whipple resection. Two weeks after surgery, the patients were randomized to be given either intravenous (IV) treatment with 370 mg (100 mg loading dose, 9 x 30 mg continuing within 10 days) of monoclonal antibody (MoAb) 494/32 (Behringwerke AG, Marsburg, Germany) or no additional anti-cancer treatment. This murine immunoglobulin (Ig) G1 antibody has been shown to strongly bind to human pancreatic cancer cells and to induce an antibody-dependent cellular cytotoxicity (ADCC). Both study groups were well matched with respect to age, sex, tumor staging, and grading. Six patients suffered from minor toxicity (vomiting and abdominal pain) after immunotherapy. Ten months after the end of the recruitment period, 65% and 53% of the patients in the treatment and control groups, respectively, had died. Of the living patients, 60% and 53% are alive with recurrent or progressive cancer disease. Median survival time was 428 days (range, 248 to 510 days) and 386 days (range, 296 to 509 days) in the treatment and control groups, respectively. The authors concluded that repeated IV treatment with the antibody 494/32 is not helpful in resectable pancreatic cancer. This study provides the first controlled data on passive immunotherapy in solid cancer.

Adult↗
PubMed1991

RFLP mapping on potato chromosomes of two genes controlling extreme resistance to potato virus X (PVX).

Two different chromosomal locations of major genes controlling extreme resistance to potato virus X (PVX) were found by restriction fragment length polymorphism (RFLP) analysis of two populations segregating for the resistance. The resistance gene Rx1 mapped to the distal end of chromosome XII, whereas Rx2 was located at an intermediate position on linkage group V in a region where reduced recombination and segregation distortion have also been observed. These linkage anomalies were due to abnormal behaviour of the chromosome contributed by the resistant parent P34. The results presented were obtained using two different strategies for mapping genes of unknown location. One approach was the use of probes revealing polymorphic loci spread throughout the genome and resulted in the mapping of Rx1. The second approach was based on the assumption of possible linkage between the resistance gene and clone-specific DNA fragments introduced from a wild potato species. Rx2 was mapped by adopting this strategy.

Blotting, Southern↗
PubMed1991

Maximal stimulation of pancreatic islet B-cells, and A-cell response to arginine, in dogs with longterm pancreatic acinar atrophy.

The response of the pancreatic islet A- and B-cells after long-standing (eight years) pancreatic duct occlusion by prolamine, and subsequently developed acinar atrophy, was studied in five beagles, and the results compared with those in six sham-operated dogs. Intravenous arginine infusion (A-cell stimulation) and a combined oral glucose and intravenous tolbutamide and glucagon infusion (B-cell stimulation) were carried out in each dog. Complete abolition of acinar function after duct occlusion was documented by the negative paraaminobenzoic acid test. In contrast, in plasma, baseline values of glucose, alpha-amino-nitrogen, insulin, glucagon, glucagon-like immunoreactivity, somatostatin-like immunoreactivity, and pancreatic polypeptide did not differ between the experimental groups. During B-cell stimulation dogs with occluded ducts had significantly reduced insulin, reduced glucagon, and reduced second phase pancreatic polypeptide compared with controls. Integrated insulin and pancreatic polypeptide were also reduced in dogs with occluded ducts. In both groups plasma and integrated values of glucose and somatostatin-like immunoreactivity did not differ. During the A-cell stimulation period dogs with occluded ducts had significantly raised alpha-amino-nitrogen but unchanged glucose and reduced insulin concentrations; in both groups the arginine-induced rise in glucagon was similar, although it was delayed in the experimental group. In the latter, integrated alpha-amino-nitrogen was raised, but integrated glucose and hormones were unchanged. We conclude that a previously intact dog pancreas that has been atrophied by duct occlusion, may be able to maintain euglycaemia for several years. There may be a complex interplay of changes induced by duct occlusion at the level of the pancreatic islets and elsewhere, which compensate for moderate insulinopenia.

Animals↗
PubMed1990

[Colon necrosis as a complication of necrotizing pancreatitis].

Necrosis of the colon is a rare but often fatal complication of necrotizing pancreatitis. Among 159 patients with necrotizing pancreatitis who were treated between 1 January 1986 and 31 December 1988, a colonic lesion developed in 10 patients (6.3%). All 10 patients underwent surgery. With regard to the time of occurrence and the extent of the lesion two types could be distinguished: first, extensive, probably ischemic colonic necrosis developed early in the course of the disease, i.e., within the 1st week; second, localized lesions mainly in the region of the left colonic flexure occurred much later and were considered to be a complication related to persistent infection in the remaining pancreatic necroses. The colonic lesions were treated by resection and fecal diversion in 9 patients and by local excision with direct closure and additional diverting colostomy in one patient. Even though the colonic complications could be controlled, only 1 of the 10 patients survived. This can be explained by the fact that all these patients had a severe form of the disease with extensive pancreatic necroses and were in a septic-toxic state with multiple organ failure at the time the colonic lesion occurred.

Adult↗
PubMed1990

Localization by restriction fragment length polymorphism mapping in potato of a major dominant gene conferring resistance to the potato cyst nematode Globodera rostochiensis.

A major dominant locus conferring resistance against several pathotypes of the root cyst nematode Globodera rostochiensis was mapped on the linkage map of potato using restriction fragment length polymorphism (RFLP) markers. The assessment of resistance versus susceptibility of the plants in the experimental population considered was based on an in vivo (pot) and an in vitro (petri dish) test. By linkage to nine RFLP markers the resistance locus Gro1 was assigned to the potato linkage group IX which is homologous to the tomato linkage group 7. Deviations from the additivity of recombination frequencies between Gro1 and its neighbouring markers in the pot test led to the detection of a few phenotypic misclassifications of small plants with poor root systems that limited the observation of cysts on susceptible roots. Pooled data from both tests provided better estimates of recombination frequencies in the linkage interval defined by the markers flanking the resistance locus.

Animals↗
PubMed1990

Estimation of recombination frequencies and construction of RFLP linkage maps in plants from crosses between heterozygous parents.

The construction of a restriction fragment length polymorphism (RFLP) linkage map is based on the estimation of recombination frequencies between genetic loci and on the determination of the linear order of loci in linkage groups. RFLP loci can be identified as segregations of singular or allelic DNA-restriction fragments. From crosses between heterozygous individuals several allele (fragment) configurations are possible, and this leads to a set of formulas for the evaluation of p, the recombination frequency between two loci. Tables and figures are presented illustrating a general outline of gene mapping using heterozygous populations. The method encompasses as special cases the mapping of loci from segregating populations of pure lines. Formulas for deriving the recombination frequencies and information functions are given for different fragment configurations. Information functions derived for relevant configurations are also compared. A procedure for map construction is presented, as it has been applied to RFLP mapping in an allogamous crop.

Alleles↗