Biomedical subjects

C Gebhardt

Publications and source records attributed to C Gebhardt.

At least 37 records · Page 2Linked to original sources

PubMed2000

Pathomorphological and histological prognostic factors in curatively resected ductal adenocarcinoma of the pancreas.

The fate of patients with potentially resectable carcinomas is not only determined by the pTNM tumor stage, but also possibly by tumor-biological factors. The aim of this study was to identify these prognostic factors in patients undergoing primary curative (R0) resection. The study retrospectively analyzed 113 patients with ductal adenocarcinoma who were operated on between 1986 and 1995. R0 resection was able to be performed in 93 patients. Lymph node metastases were found in 73%. The rates of lymph vessel and perineural invasion were 83.5% and 45%, respectively. Among the 25 carcinomas without lymph node metastases, 64% already had lymph vessel invasion and 48% had perineural invasion. The cumulative 5-year survival rate of the 91 surviving patients analyzed was 10.5%. Depending on the tumor stage we found a significant difference in 5-year survival rates between patients without lymph node metastases (26.5%) and those with lymph node involvement (5%) (P = 0.008). A multivariate analysis only identified lymph vessel invasion (L0/1), tumor size (< or = or < or =2 cm), and tumor grading (G) to have significant and independent prognostic value. Lymph vessel invasion, tumor size, and tumor grading proved to be independent factors determining long-term prognosis.

Adenocarcinoma↗

PubMed2000

[Is resection of left-sided ductal pancreatic carcinoma of value?]].

UNLABELLED: The ductal adenocarcinoma of the left part of the pancreas is concerned to be incurable. With the aid of the own patient material and the data from the literature an analysis was made to find out whether this negative prognostic assessment can be accepted. METHODS: The findings of 60 patients with tumors in the corpus/cauda region of the pancreas served as a basis for the investigation (observation time: 1986-1998). The resected tumors were reclassified according to the UICC from 1997. The survival rates were calculated with the method of Kaplan-Meier. RESULTS: Only 12 (20%) of the 60 tumors were resectable, in 6 cases only by multivisceral resection. A R0-resection was possible in 8 cases. 11 of these 12 patients had already a lymph vessel invasion (L1) and 50% an involvement of lymph nodes (pN1). After curative resection the median survival time was 17 months, after palliative resection 4 months and in cases with inoperability only 3.6 months. The survival time is identical with the results after operative treatment of carcinomas of the pancreatic head. CONCLUSIONS: Stage related the prognosis of the left sided pancreatic carcinoma is comparable with the results after similar therapy of the pancreatic head carcinoma. Therefore therapeutic nihilism is not indicated.

Adenocarcinoma↗

PubMed2000

Two cDNAs representing alleles of the nitrate reductase gene of potato (Solanum tuberosum L. cv. Desirée): sequence analysis, genomic organization and expression.

Two, different, full-length cDNAs, StNR2 and StNR3, of 3049 and 3066 nucleotides, respectively, were isolated from a Solanum tuberosum L. cv. Desirée leaf cDNA library by an RT-PCR approach. Conceptual translation of the longest open reading frame of each cDNA showed that they could encode a protein of 911 amino acids in each case with an M(r) of 102.6 and 102.5 kDa, respectively, and with 99.7% identity with each other. The cDNAs have a high degree of sequence similarity with all higher plant nitrate reductases (NRs) and possess structural characteristics expected of NADH-NR proteins, consistent with enzyme activity data. Southern analysis of genomic DNA suggested the presence of a single NR gene in the potato genome whilst studies using the mapping population F1840, and the full-length StNR2 cDNA as hybridization probe, identified a single NR locus within the potato genome that is located on chromosome XI. The two cDNAs identified here are probably derived from two transcribing alleles of this single gene. Distribution of total NR transcript and of NADH-NR activity, in different organs of compost-grown plants, depended on the level of nitrate supplied: at low nitrate level transcript and activity were detected only in leaf and stem tissue whilst at high nitrate level they could also be detected in root and stolon. An RT-PCR approach was used to differentiate between the transcripts derived from the two identified alleles and to show that the pattern of transcription of the two identified alleles of the potato nia gene, in the organs studied, is the same.

Amino Acid Sequence↗

PubMed2000

Recessive and dominant genes interfere with the vascular transport of Potato virus A in diploid potatoes.

Resistance to Potato virus A (PVA) was examined in a diploid cross involving Solanum tuberosum subsp. andigena as a resistance source. Hypersensitive resistance (HR) to PVA cosegregated with extreme resistance (ER) to Potato virus Y conferred by the dominant gene Ry(adg) on chromosome XI. Hence, HR to PVA was controlled by a novel, dominant resistance gene closely linked to Ry(adg), or Ry(adg) recognized both viruses but conferred a different type of resistance to each virus. The HR prevented systemic infection with PVA following mechanical inoculation but not following graft inoculation. Another, recessive gene, ra, that may be linked or even allelic with Ry(adg) fully blocked vascular transport of PVA in graft-inoculated plants. Hence, a possibility exists that the genes for the three types of resistance to potyviruses may reside at the same, resistance gene-rich chromosome region syntenic in solanaceous species and might be related. The gene ra acted against all of the three PVA strains tested and, therefore, the avirulence determinants could not be mapped. However, also, PVA strain-specific resistance was found in the progeny. It was overcome by mutations introduced into the viral genome-linked protein and the helper component proteinase and/or the coat protein.

Biological Transport↗

PubMed2000

Non-association of dopamine D4 and D2 receptor genes with personality in healthy individuals.

Recently, different research groups reported conflicting results with regard to an association of dopamine 4 receptor (DRD4) genotypes and the personality dimension of novelty seeking (NS). High scores for NS seemed to be associated with long alleles of a DRD4 polymorphism. Furthermore, an association between personality traits and the dopamine 2 (DRD2) receptor gene was reported. NS and persistence (PS) high scores seemed to be associated with alleles of DRD2. We examined 109 (78 female and 31 male) normal healthy individuals using Cloninger's Temperament and Character Inventory (TCI) in order to replicate these findings. We genotyped a 48 base pair variable number of tandem repeats (from two to eight repeats) polymorphism in the third exon of DRD4 and a Cys311Ser polymorphism in exon 7 of DRD2. We tested alleles and genotypes of DRD4 (allele 7 absent or present; genotype 4,4 versus 4,7), and Ser/Cys and Cys/Cys genotypes of DRD2 for associations with TCI values. NS and the alleles and genotypes of DRD4 did not show any association. In associating the genotypes of DRD2 with TCI scales (NS, harm avoidance, reward dependence and PS), we also found no association. Recent findings associating NS with DRD4 could not be replicated. With regard to DRD2, we tested a different polymorphism as published recently and could not find an association of TCI scales with the gene. The present results therefore do not provide evidence that the DRD2 and DRD4 receptor genes contribute a common and relevant effect to personality traits.

Adult↗

PubMed2000

SUT2, a putative sucrose sensor in sieve elements.

In leaves, sucrose uptake kinetics involve high- and low-affinity components. A family of low- and high-affinity sucrose transporters (SUT) was identified. SUT1 serves as a high-affinity transporter essential for phloem loading and long-distance transport in solanaceous species. SUT4 is a low-affinity transporter with an expression pattern overlapping that of SUT1. Both SUT1 and SUT4 localize to enucleate sieve elements of tomato. New sucrose transporter-like proteins, named SUT2, from tomato and Arabidopsis contain extended cytoplasmic domains, thus structurally resembling the yeast sugar sensors SNF3 and RGT2. Features common to these sensors are low codon bias, environment of the start codon, low expression, and lack of detectable transport activity. In contrast to LeSUT1, which is induced during the sink-to-source transition of leaves, SUT2 is more highly expressed in sink than in source leaves and is inducible by sucrose. LeSUT2 protein colocalizes with the low- and high-affinity sucrose transporters in sieve elements of tomato petioles, indicating that multiple SUT mRNAs or proteins travel from companion cells to enucleate sieve elements. The SUT2 gene maps on chromosome V of potato and is linked to a major quantitative trait locus for tuber starch content and yield. Thus, the putative sugar sensor identified colocalizes with two other sucrose transporters, differs from them in kinetic properties, and potentially regulates the relative activity of low- and high-affinity sucrose transport into sieve elements.

Amino Acid Sequence↗

PubMed2000

Genome scan for susceptibility loci for schizophrenia.

OBJECTIVE: Schizophrenia is a relatively common, often chronic and debilitating mental illness. Evidence from various studies has clearly demonstrated that genetic factors contribute substantially to the etiology. The goal of this study was to identify chromosomal regions likely to contain schizophrenia susceptibility genes. METHODS: A genome-wide map of 388 microsatellite DNA markers was genotyped in 5 schizophrenia families. Nonparametric linkage analysis (Genehunter) was used to assess the pattern of allele sharing at each marker locus relative to the presence of disease. RESULTS: Nonparametric linkage scores did not reach a genome-wide level of statistical significance (p < 0.00002) or a p value suggestive of linkage (p < 0.007) for any marker; however, one p value suggested replicated linkage (p < 0.01) at chromosome 6p24 in region D6S309 (p = 0.0047). Furthermore, 11 markers resulted in p < 0.05 at chromosomes 6p, 6q, 10q, 12q and 14q. CONCLUSIONS: Despite the differences in diagnostic schemes, in markers used and methods of analyses between studies published so far, we think that our result supports the notion that there is possibly some consistent evidence for replicated linkage of a schizophrenia susceptibility locus around the region of D6S309 at chromosome 6p24.

Adult↗

PubMed2000

Association studies of candidate genes in bipolar disorders.

The aim of the investigation was to test genes for predisposition to bipolar affective disorder. Therefore, we studied candidate genes in a sample of unrelated patients (n = 102) and healthy controls (n = 79) of Austrian origin, searching for a possible association between polymorphic DNA markers of 5 candidate genes (serotonin transporter, 5-HTT; serotonin 2a receptor, 5-HT2a; dopamine D2 receptor, DRD2; dopamine D3 receptor, DRD3; dopamine transporter, DAT1) and bipolar disorder. There was an association between allelic and genotypic frequencies of 5-HTT and affection status (p = 0.014 and p = 0.017, respectively). However, after correction for multiple comparisons (Bonferroni), these results did not remain significant. Nevertheless, the findings might suggest that alterations in the structure of 5-HTT are involved in the pathogenesis of bipolar disorder, which could have major implications in treatment. No association between 5-HT2a, DRD2, DRD3, DAT1 and bipolar disorder was found.

Adult↗

PubMed2000

Development of SCAR markers to the PVY resistance gene Ryadg based on a common feature of plant disease resistance genes.

Sequence-characterized amplified regions (SCARs) were developed, based on nucleotide differences within resistance gene-like fragments isolated from a potato plant carrying the Ryadg gene, which confers extreme resistance to potato Y potyvirus (PVY). It originates from Solanum tuberosum subsp. andigena, and a susceptible potato plant. SCARs were tested using 103 potato breeding lines and cultivars with diverse genetic backgrounds derived from Europe, North America, and Japan. Two markers showed high accuracy for detection of the Ryadg gene. The SCAR marker RYSC3 was generated only in genotypes carrying Ryadg. The SCAR marker RYSC4 was detected in all genotypes carrying Ryadg but also in four PVY-susceptible genotypes. Neither marker was detected in genotypes carrying other Ry genes originating from different species than S. tuberosum subsp. andigena. Therefore, these SCAR markers should be powerful tools in marker-assisted selection for Ryadg in potato breeding programs, and should also be useful for cloning of the Ryadg gene.

Breeding↗

PubMed1999

Anoxic decrease in potassium outward currents of hippocampal cultured neurons in absence and presence of dithionite.

The effect of brief anoxia on voltage dependent K(+)-currents of hippocampal cultured neurons was studied. The oxygen scavenger dithionite (hydrosulphite) was previously used for creating zero oxygen pressure. However, dithionite consumes O(2) in parallel with generation of superoxide radicals and is a strongly reducing agent. In this study anoxia was produced by perfusion of the neurons with a solution bubbled with nitrogen for 1 h using a chamber with an argon layer isolating the anoxic bath flow from atmospheric oxygen in presence and absence of dithionite. Oxygen partial pressure of dithionite-free solution was determined by oxygen dependent quenching of the phosphorescence of Pd-coproporphyrin to be 0.15+/-0. 02 Torr (values are given as mean+/-S.D., n=6). Slow (I(K))- and fast (I(A))-inactivating K(+)-currents were measured with the patch clamp technique in the whole cell configuration. Exposure of the neurons to anoxia reversibly decreased the amplitude of I(K) at a test pulse of 0 mV to 77+/-12% (n=7) in absence and to 83+/-7% (n=6) in presence of 2 mM dithionite; the amplitude of I(A) decreased to 78+/-11% in absence and to 82+/-9% in presence of 2 mM dithionite. Voltage dependence of activation and inactivation shifted 5 min after exposure to anoxia reversibly by about 6 mV in depolarizing direction. The decay times of inactivation were insensitive to anoxia. Dithionite had no significant effects on K(+)-currents. In 15 of 21 neurons not employed for analysis on K(+)-currents, a reversible increase in holding current under dithionite was observed. In absence of dithionite in 4 of 19 neurons the holding current reversibly increased during anoxia. Although dithionite does not affect K(+)-currents, changes in holding current show that the dithionite may affect neurons independently of oxygen deprivation.

Animals↗

PubMed1999

Cystic neoplasms of the pancreas--cystadenomas and cystadenocarcinomas.

INTRODUCTION: Among the rare cystic pancreatic tumors, serous and mucinous cystadenoma and mucinous cystadenocarcinoma are most often diagnosed. CASE: We report on a total of 21 patients with cystic neoplasms who underwent surgery, 11 of whom had mucinous cystadenocarcinoma. Of the 10 remaining patients, serous and mucinous cystadenoma were diagnosed in two groups of five. A common feature of all cystic neoplasms is slow growth, leading to clinical symptoms at an advanced stage, with tumors frequently becoming enormous. RESULTS: In approximately half of the cases, diagnosis was possible by means of ultrasound, computed tomography and, in three instances, by preoperative percutaneous aspiration. Differential diagnosis of pseudocysts proved to be most difficult. CONCLUSION: Given the low operative risk, resection should always be performed in instances where findings cannot be clearly identified. Moreover, compared with ductal pancreatic carcinomas, the prognosis of a cystadenocarcinoma after early resection is extremely favorable, so that postponing resection might reduce the patient's prospects of being cured.

Adult↗

PubMed1999

Multivisceral resection of advanced colorectal carcinoma.

BACKGROUND AND AIMS: In about 10% of patients with carcinoma of the colorectum, the tumour has already invaded contiguous organs or else inflammatory tumorous adhesions involving neighbouring structures are found. In such a situation, the question arises whether one should perform a multivisceral resection, the usefulness of which in terms of surgical risk and late oncological results have been investigated in the present study. PATIENTS AND METHODS: A total of 173 patients with colorectal carcinoma who underwent a multivisceral resection during the period between 1984 and 1995 are reported. Excluded from the study were patients with recurrent tumour or distant metastases. RESULTS: In the majority of cases (63%), the primary tumour originated in the sigmoid colon or rectum. In 102 patients, only a single neighbouring organ was additionally involved, while the remaining patients had involvement of two or more contiguous organs. In 140 patients, the resection was curative, while in the remaining patients an R1/2 situation presented. In the curative group, tumour infiltration was confirmed histologically in 55% of the cases, while in the remaining patients a peritumourous adhesion had mimicked tumour invasion. Postoperative surgical complications occurred in only 1.4% of the interventions, a figure identical to the incidence of complications seen with conventional limited operations. The same applied to the postoperative 30-day mortality rate of 3.6%. The 5-year survival rate of the overall group of patients undergoing multivisceral resection was 42%, that of the subgroup undergoing curative surgery was 51%, and that of the subgroup receiving only palliative resection was 0%. Calculation of the stage-related 5-year survival rates for Union Internationale Contra la Cancrum stage-II and stage-III tumours revealed figures of 58% and 43%, respectively. After non-extended resection, the respective survival rates were identical (60% and 41%). CONCLUSION: An identical surgical risk and survival rates for curative resection, equally as good as those seen with conventional, non-extended procedures, justify the liberal use of multivisceral resection in the surgical treatment of colorectal carcinomas directly invading neighbouring organs.

Abdominal Muscles↗

PubMed1999

PCR-based cloning and segregation analysis of functional gene homologues in Beta vulgaris.

To analyse genetic factors that potentially affect sugar quality and yield in Beta vulgaris, we designed primers based on 18 homologous ESTs and conserved regions of 32 heterologous ESTs encoding gene products that act in the Calvin cycle, the oxidative pentose phosphate cycle, photorespiration, synthesis, transport and degradation of sucrose, glycolysis, the citric acid cycle, nitrogen metabolism and osmoprotection. Data on the amplification of 54 gene homologues from B. vulgaris are presented. Among these are 35 homologues for which DNA sequence information from B. vulgaris is now available for the first time. For genetic mapping a PCR-based strategy using CAPS (cleaved amplified polymorphic sequence), DFLP (DNA fragment length polymorphism), SSCP (single-strand conformation polymorphism) and HD (heteroduplex) analysis was adopted. RFLP analysis was also used in some cases. The different techniques used for the detection of polymorphisms are evaluated with respect to their sensitivity and versatility. In all, 42 functional genes have been assigned to the nine linkage groups of sugar beet.

Alleles↗

PubMed1999

Molecular cloning and characterization of the enzyme UDP-glucose: protein transglucosylase from potatodaggerdaggerThis paper is specially dedicated to the memory of Dr Juana S. Tandecarz, deceased on December 10, 1996.

UDP-Glc:protein transglucosylase (UPTG) (EC 2.4.1.112) is an autocatalytic glycosyl-transferase previously postulated as a protein that primes starch biosynthesis. Polyclonal antibodies raised against UPTG purified from potato (Solanum tuberosum L.) tubers were used to screen a potato swelling stolon tip cDNA expression library. The isolation, cloning and sequencing of two cDNAs corresponding to UPTG are described. Recombinant UPTG was labelled after incubation with UDP-[(14)C]-Glc and Mn(2+), indicating that it was enzymatically active. It was determined that purified as well as recombinant UPTG can be reversibly glycosylated by UDP-Glc, UDP-Xyl or UDP-Gal. RNA hybridization studies and western blot analysis indicate that UPTG mRNA and protein are expressed in all potato tissues. Databank searches revealed a high degree of identity between UPTG and several plant sequences that encode for proteins with apparent localization at the cytoplasmic face of the Golgi apparatus and at plasmodesmata. The biochemical properties of UPTG and the apparent lack of a signal peptide that could allow its entrance into plastids argue against the postulated role of UPTG in starch synthesis and point towards a possible role of the protein in the synthesis of cell wall polysaccharides.

Journal Article↗

PubMed1999

Identification of cytosolic Mg2+-dependent soluble inorganic pyrophosphatases in potato and phylogenetic analysis.

Using polyclonal antibodies raised against a previously cloned potato Mg2+-dependent soluble inorganic pyrophosphatase (ppa1 gene) [8], a second gene, called ppa2, could be isolated. A single locus homologous to ppa2 was mapped on potato chromosomes, unlinked to the two loci identified for ppa1. From a phylogenetic and structural point of view, the PPA1 and PPA2 polypeptides are more closely related to prokaryotic than to eukaryotic Mg2+-dependent soluble inorganic pyrophosphatases (soluble PPases). Subcellular localization by immunogold electron microscopy, using sections from leaf parenchyma cells, showed that PPA and PPA2 are localized to the cytosol. Based on these observations, the likely phylogenetic origin and the physiological significance of the cytosolic soluble pyrophosphatases are discussed.

Amino Acid Sequence↗

PubMed1999

Pulmonary aspergilloma - clinical findings and surgical treatment.

The management of pulmonary aspergilloma is still a topic of discussion. Demonstrating several cases of pulmonary aspergilloma, their clinical course and their follow-up, we try to contribute some arguments for the preference of an early operation. Between 1992 and 1998, 18 patients underwent thoracotomy for treatment of pulmonary aspergilloma. The most common indication for operation were hemoptysis [6] and indeterminate mass [6]. Lobectomy was the most frequent operation [11]. Underlying diseases were bronchiectasis [10], tuberculosis [3], carcinoma [2], blebs [2], and epitheloid granuloma. Two patients had postoperative complications, another three died later in the clinical course because of liver failure, septicemia, and persisting air leakage and sepsis. We recommend early resection of symptomatic, cavitating aspergilloma in the simple form and even with an inflammatory reaction of the surrounding tissue. Especially low-risk patients profit highly from an early operation. High-risk patients should be operated on only in cases of life-threatening complications.

Adult↗

PubMed1998

Isolation, characterisation and mapping of simple sequence repeat loci in potato.

Solanum tuberosum L. DNA sequences containing simple sequence repeat (SSR) motifs were extracted from the EMBL database, cDNA and selectively enriched small-insert DNA libraries. Enrichment was achieved using either triplex affinity capture or single-strand hybridisation selection. One hundred and twelve primer pairs which successfully amplified products of the correct size from potato DNA were ultimately designed and synthesised. Ninety-eight of these revealed length polymorphisms in a panel of four diploid and two tetraploid clones, in agreement with the high information content of this class of markers which has been found in other species. All of the markers were assigned a quality score of 1-5 based on their potential usefulness. Eighty-nine loci from 65 of the primer pairs were located on two genetic linkage maps of potato by segregation analysis of the amplified alleles. Fifty-two of the SSRs were clearly single locus. The maps were aligned using 23 SSR primer pairs and 13 RFLP loci mapped in both populations. The markers described constitute a class which should replace Restriction Fragment Length Polymorphisms (RFLP) as the markers of choice for future genetic studies in potato. The sequences of the primers, together with other information on these markers are provided.

Base Sequence↗

PubMed1998

[Multi-visceral resection in colorectal carcinoma].

Report of 173 patients with colorectal carcinoma, who were submitted to a multivisceral resection. After curative operation a histologically proven infiltration of neighbouring organs could be seen in 55% of cases, whereas in the other patients only inflammatory adhesions were identified. Postoperative surgical complications were observed in 11.4% and were identical with the level of complications in conventionally operated patients. Also comparable were the postoperative mortality rates (3.6%/3.4%). The 5-year survival rate of all multiviscerally resected patients was 42%, after curative resection 51%. The UICC-stage related survival rates were 58% and 43% in stage II and III, versus 60% and 41% after conventional resection. The identical operative risk and identical survival rates justify the application of multivisceral resection in the treatment of colorectal carcinoma.

Abdominal Neoplasms↗