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T Günther

Publications and source records attributed to T Günther.

At least 19 recordsLinked to original sources
PubMed2000

The Helicobacter pylori vacA s1, m1 genotype and cagA is associated with gastric carcinoma in Germany.

BACKGROUND: The H. pylori vacuolating cytotoxin encoded by vacA and the cytotoxin-associated protein encoded by cagA are considered to be important virulence determinants that have been implicated in the development of peptic ulcers and gastric carcinoma. However, conflicting results regarding the association between these virulence factors and clinical disease have been reported from different geographic regions. AIMS: To determine the frequency of vacA genotypes, vacuolating cytotoxin activity, and cagA in H. pylori isolates obtained from patients with gastric cancer in Germany. METHODS: H. pylori isolates were obtained from 34 patients with gastric cancer and from 35 subjects with asymptomatic H. pylori gastritis. vacA genotypes and cagA were identified by PCR. Cytotoxic activity was determined by HeLa cell assays. Gastritis was assessed according to the updated Sydney System. RESULTS: The H. pylori vacA s1,m1 genotype was significantly more frequent in patients with gastric cancer (24/34, 70.6%) as compared with controls (12/35, 34. 3%) (p = 0.005). Cytotoxic activity was detected in 24 (70.6%) and 15 (42.9%) H. pylori isolates from gastric cancer patients and controls, respectively (p = 0.03). The cagA gene was identified in 30 (88.2%) and 21 (60%) H. pylori isolates in the respective groups (p = 0.01). CONCLUSIONS: Our study suggests a significant association between the H. pylori vacA s1,m1 genotype, cytotoxic activity, cagA, and gastric cancer. Detection of H. pylori possessing these virulence determinants may help to identify patients being at an increased risk to develop gastric cancer in our population.

Adenocarcinoma↗
PubMed2000

Genetic ablation of parathyroid glands reveals another source of parathyroid hormone.

The parathyroid glands are the only known source of circulating parathyroid hormone (PTH), which initiates an endocrine cascade that regulates serum calcium concentration. Glial cells missing2 (Gcm2), a mouse homologue of Drosophila Gcm, is the only transcription factor whose expression is restricted to the parathyroid glands. Here we show that Gcm2-deficient mice lack parathyroid glands and exhibit a biological hypoparathyroidism, identifying Gcm2 as a master regulatory gene of parathyroid gland development. Unlike PTH receptor-deficient mice, however, Gcm2-deficient mice are viable and fertile, and have only a mildly abnormal bone phenotype. Despite their lack of parathyroid glands, Gcm2-deficient mice have PTH serum levels identical to those of wild-type mice, as do parathyroidectomized wild-type animals. Expression and ablation studies identified the thymus, where Gcm1, another Gcm homologue, is expressed, as the additional, downregulatable source of PTH. Thus, Gcm2 deletion uncovers an auxiliary mechanism for the regulation of calcium homeostasis in the absence of parathyroid glands. We propose that this backup mechanism may be a general feature of endocrine regulation.

Animals↗
PubMed2000

Expression of metallothionein II in intestinal metaplasia, dysplasia, and gastric cancer.

Differential display is a valuable tool for the identification of differentially expressed genes in human carcinogenesis and development. The search for differentially expressed genes in gastric cancer and its premalignant lesions may help to define molecular alterations in the gastric mucosa that may precede the development of gastric cancer. Using the differential display technique, we identified a cDNA fragment, encoding metallothionein (MT) IIa mRNA. We performed immunohistochemical analysis using a monoclonal antibody directed against human MT and tissues obtained from 34 patients with gastric cancer and 20 healthy individuals to determine the expression and localization of MT in gastric cancer and its associated premalignant lesions and to correlate our findings with histomorphological features and Helicobacter pylori status. In addition, MT expression was assessed in gastric tissues obtained from patients with gastric cancer and first-degree relatives of patients with gastric cancers and healthy individuals using reverse transcription-PCR analysis. Northern blot analysis confirmed the overexpression of MT IIa in gastric cancer. In the normal gastric tissues, no MT immunoreactivity was observed at the superficial gastric epithelium toward the top of gastric glands. However, MT immunoreactivity was detected at the foveolar neck of the gastric glands. Immunohistochemical analysis revealed an intense MT immunoreactivity in gastric cancer cells, independent of tumor stage, grade of differentiation, or tumor type. Furthermore, areas of dysplasia and intestinal metaplasia also exhibited intense MT immunoreactivity. Reverse transcription-PCR analysis of gastric biopsies obtained from first-degree relatives of patients with gastric cancer revealed the frequent expression of MT Ia in this high-risk group as compared with healthy subjects (P < 0.01). The overexpression of MT in gastric cancer and the expression of MT in intestinal metaplasia and dysplasia, as well as the expression of MT in the gastric mucosa of first-degree relatives of patients with gastric cancer, point to a role for MT in the early process of malignant transformation of the gastric mucosa.

Adult↗
PubMed2000

Is typing of metaplasia at the squamocolumnar junction revealing its aetiology?

Until recently, intestinal metaplasia (IM) at the squamocolumnar junction (SCJ) was ascribed to Barrett's mucosa (BM), which arises from gastro-oesophageal reflux. Recent studies, however, have shown that IM at the SCJ can also be induced, for example, by Helicobacter pylori (HP). The aim of this study was to investigate whether the type of IM might be helpful in the differentiation between these two aetiologies. Biopsies from the antrum, corpus and immediately below the Z-line were taken from 443 patients. Eighty-three of them showed IM below the Z-line. In these, the endoscopic aspect of the Z-line was classified as either unremarkable (n=49) or suspected of BM (n=34). Typing of IM was done using Gomori's aldehyde fuchsin-Alcian blue staining. Overall, age, HP status and erosive oesophagitis had no influence on the IM type. Type-III IM (n=24) was more frequent in men (P=0.0371) and related to endoscopic BM (P<0.0001). Type-I/II IM (n=59) was associated with an unremarkable Z-line (P<0.0001) and was linked to multifocal gastric IM (P=0.016) and HP (P=0.0011). In conclusion, it was shown that, in the presence of a normal Z-line, especially in the absence of HP, type-III IM is suggestive of BM. The diagnosis of short or ultra-short segment BM should therefore include endoscopic, histological and histochemical characteristics.

Adult↗
PubMed2000

Repair of interrupted aortic arch: results after more than 20 years.

BACKGROUND: This study focused on the influence of concomitant anomalies, the individual surgical approach, and the probability for reinterventions. METHODS: Between 1975 and 1999, 94 patients with interrupted aortic arch were evaluated for short- and long-term results after surgical treatment. RESULTS: Interrupted aortic arch was associated mainly with a ventricular septal defect (85%) and left ventricular outflow tract obstruction (LVOTO, 13%). Mean follow-up was 6.7 years (median 6.9 years, 628.4 patient years). A single-stage operation was performed in 76 cases. Early mortality for two-stage procedures was 37% and late mortality was 26%, compared with single-stage procedures, with an early mortality of 12% and a late mortality of 20%, respectively. Early mortality in patients with additional LVOTO was 42% and late mortality was 50%. Freedom from reoperation at 5 years was 62%, and at 10 years was 49%. Reinterventions were performed mainly for residual arch stenosis, also with bronchus or tracheal compression, or LVOTO. CONCLUSIONS: Arch continuity and repair of associated anomalies can be achieved with an acceptable overall risk in this often complex entity. Associated anomalies play an important role in the outcome. Single-stage repair with primary anastomosis of the arch should be the surgical goal. The long-term probability for reoperation is high.

Adolescent↗
PubMed2000

Mitral-valve replacement in children under 6 years of age.

OBJECTIVE: In patients with congenital mitral-valve disease, reconstructive surgery is the primary goal. However, in cases with severely dysplastic valves or failed repair, mitral-valve replacement (MVR) is the only option. We analyzed, retrospectively, data of 35 patients younger than 6 years of age, who underwent MVR at our institution. METHODS: Between 1974 and 1997, 35 children underwent MVR. The ages ranged from 2.7 months to 5.5 years (mean=1. 9+/-1.7 years) and body weight varied between 3.2 and 16.7 kg (mean=8.2+/-4 kg). The main indication (57%) for valve replacement was severe mitral-valve insufficiency. Eighteen patients (51%) had undergone at least one previous reconstructive operation (mean=1. 46+/-1.86 years) before the MVR. In 29 cases (83%), mechanical prostheses were implanted. Six patients received a bioprosthesis. The size of the prostheses ranged between 14 and 27 mm. RESULTS: The overall hospital mortality was 17.1% (6/35), and decreased from 33 (1974-1985) to 11.5% (1986-1997). Seven children died late. The actuarial survival after 20 years was 51.2+/-13.3%. Eight patients (23%) required 10 reoperations (8.2%/100 patient-years). Freedom from reoperation at 10 years was 50+/-22%. Valve-related complications were thrombo-embolism (n=2; 1.6%/100 patient-years), hemorrhage (n=1; 0.8%/100 patient-years), structural deterioration (n=3; 2.5%/100 patient-years) and non-structural dysfunction (n=3; 2. 5%/100 patient-years). Follow-up is 96% complete, with a total of 122 patient-years (mean=4.2+/-4.7 years). Eighty six percent of the patients are in New York Heart Association (NYHA) class I, 95% have sinus rhythm and 59% do not need medication. All survivors, except for those who received a bioprosthesis, were placed on a regimen of Phenprocoumon (Marcumar((R))), aiming to maintain the International Normalized Ratio (INR) between 2.5 and 3.5. In one third of these children, self-management of oral anticoagulation was performed either by the patients or their parents. CONCLUSIONS: MVR in small children still carries a high risk. In our experience, the long-term results are satisfying. After failed reconstructive surgery, or as a primary procedure, we prefer mechanical prostheses. They are well tolerated and the incidence of anticoagulation-related complications is low.

Chi-Square Distribution↗
PubMed2000

Mouse genetics have uncovered new paradigms in bone biology.

In the past decade, mouse models have improved our understanding of bone biology. Given the fact that osteoporosis is among the most common diseases, this review will focus on the regulation of differentiation and function of the bone-resorbing osteoclasts and the bone-forming osteoblasts. Mouse genetic studies have revealed a cascade controlling osteoclastogenesis that includes the recently discovered molecules osteoprotegerin, RANK and RANK ligand. In terms of osteoblast differentiation, CBFA1 and Indian hedgehog have been identified as activators. Moreover, recent evidence demonstrates that osteoblast function is, at least in part, controlled by the hypothalamus.

Animals↗
PubMed2000

Mdm2 gene amplification in gastric cancer correlation with expression of Mdm2 protein and p53 alterations.

Mdm2, localized on chromosome 12, is considered a negative regulator of p53 function and seems to play a role in the pathogenesis of a variety of tumors. The mdm2 amplification in advanced-stage gastric carcinoma has not yet been investigated. Mdm2 amplification was determined in 43 gastric carcinomas, and the genetic results were correlated with mdm2 protein expression, p53 alterations, and clinicopathologic data. The tumors were classified according to Lauren: 20 intestinal-type tumors, 19 tumors of diffuse growth inclusive of a primary small cell carcinoma, and 4 carcinomas with mixed differentiation. Staging was based on the pTNM classification system. Mdm2 and p53 were demonstrated by immunohistology on formalin-fixed and paraffin-embedded tumor tissue. The mdm2 oncogene was amplified by nonradioactive hybridization of tumor DNA with an mdm2 cDNA probe. The Southern blots were evaluated densitometrically. For p53 mutation screening, we analyzed the highly conservative regions of the p53 gene (exons 4 to 8) with the use of the polymerase chain reaction-single-strand conformation polymorphism technique. Polymerase chain reaction products with band shifting were directly sequenced. Mdm2 amplification was demonstrated in 18 tumors (41.8%). The mdm2 gene was amplified more frequently in carcinomas with a diffuse growth pattern. Gastric carcinomas of the intestinal type, however, showed a higher frequency of p53 alterations. There was no statistical significance of the molecular genetic and immunohistologic results of the mdm2/p53 status to staging as well as to age and sex of the patients. The mdm2/p53 pathway is a part of the carcinogenesis of gastric carcinoma. Only approximately 20% of gastric carcinomas failed to show mdm2 and/or p53 alterations. The upregulation of the mdm2 oncogene and the accompanying inactivation of the tumor suppressor gene 53 seem to play a role above all in carcinomas of the diffuse type.

Adult↗
PubMed2000

Telomerase activity and expression of hTRT and hTR in gastrointestinal stromal tumors in comparison with extragastrointestinal sarcomas.

Stromal tumors of the gut (GISTs) have rarely been analyzed for genetic alterations. This study aimed at determining telomerase activity and the expression of the telomerase subunits human telomerase reverse transcriptase (hTRT) and human telomerase RNA (hTR) in GISTs and extragastrointestinal neurogenic or myogenic sarcomas. Telomerase activity was investigated using the telomeric repeat amplification protocol assay in 21 GISTs, recurrences and liver metastases from 16 patients, and in 22 leiomyosarcomas and 21 malignant peripheral nerve sheath tumors (MPNSTs), which served as reference tumors. Expression of hTRT and hTR mRNA was investigated using reverse transcription-PCR. Thirteen GISTs were localized in the stomach and three in the small intestine. Two tumors were benign. In one case, the biological behavior was uncertain. In 67% of GISTs, high telomerase activity was found, whereas high activity was noted in only 18% of leiomyosarcomas and in 48% of MPNSTs. There was no activity in two benign and two malignant GISTs. In one malignant tumor of the small intestine, the primary tumor showed no activity at first but a marked activity in its recurrence. In the tumor with uncertain behavior, telomerase activity and hTRT expression were only weak. In all GISTs showing telomerase activity, the catalytic subunit hTRT was expressed. All GISTs and extragastrointestinal sarcomas expressed hTR. In comparison with leiomyosarcomas and MPNSTs, malignant GISTs showed a higher telomerase activity, which, however, was not seen in benign GISTs. It is possible that telomerase activity occurs during the progression of malignant GISTs. There was a correlation between telomerase activity and the expression of hTRT.

Adult↗
PubMed1999

Characterization of Mg(2+) efflux from rat erythrocytes non-loaded with Mg(2+).

Non-Mg(2+)-loaded rat erythrocytes with a physiological level of Mg(2+)(i) exhibited Mg(2+) efflux when incubated in nominally Mg(2+)-free media. Two types of Mg(2+) efflux were shown: (1) An Na(+)-dependent Mg(2+) efflux in NaCl and Na gluconate medium, which was inhibited by amiloride and quinidine, as was Na(2+)/Mg(2+) antiport in Mg(2+)-loaded rat erythrocytes; and (2) an Na(+)-independent Mg(2+) efflux in sucrose medium and choline Cl medium, which may be differentiated into SITS-sensitive Mg(2+) efflux at low Cl(-)(o) (in sucrose) and into SITS-insensitive Mg(2+) efflux at high Cl(-)(o) (in 150 mmol/l choline Cl).

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1999

Multimodal imaging of residual function and compensatory resource allocation in cortical atrophy: a case study of parietal lobe function in a patient with Huntington's disease.

In a case of Huntington's disease (HD) with dementia and pronounced parieto-frontal atrophy, the functional state of the affected regions was investigated using functional magnetic resonance imaging (fMRI) and fluorodeoxyglucose-positron emission tomography (FDG-PET). It was observed that although parietal areas showed extensive atrophy and reduced resting glucose metabolism, the patient performed with similar accuracy but with longer response time in a visuospatial task compared with healthy control subjects. At the same time, the blood oxygen level-dependent (BOLD) fMRI signal in these areas, which are involved in visuospatial processing, showed a similar task-dependent modulation as in control subjects. The signal amplitude (signal percent change) of the task-dependent activation was even higher for the HD patient than in the control group. This residual functionality of parietal areas involved in visuospatial processing could account for the patient's performance in the task concerned, which contrasted with his poor performance in other cognitive tasks. The increased percent-signal change suggests that a higher neuronal effort was necessary to reach a similar degree of accuracy as in control subjects, fitting well with the longer reaction time. We propose that fMRI should be considered as a tool for the assessment of functionality of morphologically abnormal cortex and for the investigation of compensatory resource allocation in neurodegenerative disorders.

Atrophy↗
PubMed1999

[Gastrointestinal stromal tumors--problems in diagnosis and therapy].

Gastrointestinal stromal tumors (GIST), which form a rare group of neoplasias of the gastrointestinal tract, have not yet been fully investigated. Although good progress has been made in their diagnosis, classification of these lesions with regard to their histogenesis and biological behavior remains problematic. Between 1994 and 1998, 18 GIST patients underwere operation in the Department of Surgery. Twelve of these patients (67%) had stromal tumors in the stomach, and six (33%) had intestinal stromal tumors. The primary tumor could be removed in all patients with R0 resection. Six patients developed hematogenous liver metastasis, with the size of their primary tumor exceeding 10 cm. Extrahepatic distant metastases were not found in any case. Lymphadenectomy showed that lymph node metastases did not occur. Histological evaluation was made according to the guidelines of Lewin, Weinstein and Riddell. Currently established therapy is limited to complete surgical resection of the primary tumor and its metastases. Adjuvant or neoadjuvant chemotherapy approaches have failed.

Adult↗
PubMed1999

P53-protein accumulation and MDM2-protein overexpression in gastric carcinomas. No apparent correlation with survival.

Forty-five cases of primary gastric carcinoma were investigated immunohistochemically for p53 protein accumulation and MDM2 protein overexpression. The results were correlated with pathological and clinical data. The incidence of p53 accumulation was 12 of 45 (26.7%) cases and that of MDM2 expression was 30 of 45 (66.7%). Eighteen of 45 (40%) cases showed MDM2 overexpression without p53 accumulation. All of the 12 p53-positive cases exhibited a co-expression of MDM2. Accumulation of p53 and MDM2 overexpression correlated with the grade of malignancy. MDM2 expression occurred more often in intestinal carcinomas than in the diffuse types. No correlation was found between p53 accumulation and the histopathology of gastric cancer. p53 accumulation and MDM2 overexpression did not correlate with tumor size, nodal status, presence of metastases, age or survival. p53 alteration, which seems to be a late step in gastric carcinogenesis, is a marker of higher grade tumors. MDM2 functions as a cofactor of p53 in late gastric carcinogenesis. An independent role of this oncoprotein in gastric carcinogenesis also seems possible. Neither p53 nor MDM2 is a useful prognostic indicator.

Adenocarcinoma↗
PubMed1999

Role of aging in the expression of Helicobacter pylori gastritis in the antrum, corpus, and cardia.

BACKGROUND: Earlier studies identified a pylorocardial expansion of chronic gastritis. We investigated the age-dependent changes in grading and topography of Helicobacter pylori gastritis. METHODS: Antral, corpus, and cardial biopsy specimens from 216 H. pylori-positive patients with no peptic ulcer disease (PUD), malignancy, or Barrett's oesophagus were evaluated with haematoxylin and eosin and modified Giemsa. The patients were separated into four equal-sized age groups (1, < 46 years; II, 46-56 years; III, 57-68 years; IV, > 69 years). Sydney-system gradings of bacterial density and activity and degree of gastritis were used to calculate gastritis sum scores for age- and biopsy site-dependent comparisons. The prevalence of intestinal metaplasia (IM) and atrophy was also compared. RESULTS: Mean antral sum scores decreased slightly in group IV but were higher than those in the corpus or cardia in all groups (P < 0.05 each). In the corpus mean scores increased in groups II-IV versus group I (P < 0.05 each), and aging was associated with a significant increase in bacterial density and active inflammation. The cardia scores remained virtually constant in all groups and exceeded significantly that in the corpus in group I. IM and atrophy increased with age, occurring more frequently and earlier in the antrum and cardia than in the corpus. CONCLUSIONS: Progression of gastritis with age involves the corpus but not the cardia. Antral inflammation decreases slightly in patients of advanced age.

Adult↗
PubMed1999

Multimodal treatment of neuroendocrine tumors of the pancreas and the ampulla of Vater.

Neuroendocrine tumors are not seen frequently. They are most commonly located in the small bowel including the vermiform appendix. Neuroendocrine tumors of pancreatic origin are extremely rare. Symptoms caused by excessive hormone production by large liver metastases often lead to their diagnosis. Preoperative diagnostics include analysis of specific hormones in serum and urine, ultrasound, CT and somatostatin receptor scintigraphy. Liver metastases of neuroendocrine tumors of the pancreas are common at the time of diagnosis. Curative resection should be performed whenever possible, although patients often benefit from debulking procedures, too. Liver metastases can be subjected to surgical resection, embolization, regional chemotherapy or local procedures such as alcohol injection or cryoablation. As an exception, liver transplantation can be considered in selected cases where radical surgery for the primary tumor could be performed and extrahepatic metastases are not present. Supplementary or alternative options include octreotide and/or interferon-alpha administration. In this article, we report on 6 patients suffering from primary neuroendocrine tumors of the pancreas or the ampulla of Vater who were treated at our department over the past 5 years. In addition, we discuss our own experience with this rare condition in the light of the recent literature.

Adult↗
PubMed1998

Multimodal imaging of residual function and compensatory resource allocation in cortical atrophy: a case study of parietal lobe function in a patient with Huntington's disease.

In a case of Huntington's disease (HD) with dementia and pronounced parieto-frontal atrophy, the functional state of the affected regions was investigated using functional magnetic resonance imaging (fMRI) and fluorodeoxyglucose-positron emission tomography (FDG-PET). It was observed that although parietal areas showed extensive atrophy and reduced resting glucose metabolism, the patient performed with similar accuracy but with longer response time in a visuospatial task compared with healthy control subjects. At the same time, the blood oxygen level-dependent (BOLD) fMRI signal in these areas, which are involved in visuospatial processing, showed a similar task-dependent modulation as in control subjects. The signal amplitude (signal percent change) of the task-dependent activation was even higher for the HD patient than in the control group. This residual functionality of parietal areas involved in visuospatial processing could account for the patient's performance in the task concerned, which contrasted with his poor performance in other cognitive tasks. The increased percent-signal change suggests that a higher neuronal effort was necessary to reach a similar degree of accuracy as in control subjects, fitting well with the longer reaction time. We propose that fMRI should be considered as a tool for the assessment of functionality of morphologically abnormal cortex and for the investigation of compensatory resource allocation in neurodegenerative disorders.

Adult↗
PubMed1998

Long-term results after repair of complete atrioventricular septal defects: analysis of risk factors.

BACKGROUND: We analyzed data from 320 patients to evaluate the impact of different preoperative, operative, and postoperative factors on the outcome after repair of complete atrioventricular septal defect. METHODS: Between October 1974 and December 1995, 320 patients with complete atrioventricular septal defect not associated with major cardiac anomalies were operated on. Two hundred seventy-four patients underwent total repair. Sixty-three patients (23%) were less than 6 months old. One hundred ninety-eight (72.2%) underwent primary repair. Seventy-six patients (27.7%) had a previous palliative operation. RESULTS: Operative mortality in patients who underwent primary repair decreased from 17.6% (1974 to 1979) to 5.0% (1990 to 1995) despite an increase in the number of patients younger than 6 months. In patients undergoing a two-stage procedure operative mortality was 3.9% (late mortality, 7.9%). Young age (<6 months) was an incremental risk factor (p = 0.008) for operative mortality in the early study period. Coarctation of the aorta (p = 0.02) and severe dysplastic left atrioventricular valve (p = 0.001) were associated with a higher risk for operative mortality. Freedom from reoperation at 10 years was 82.5% +/- 3.8%. CONCLUSIONS: In patients with complete atrioventricular septal defect, primary repair is the treatment of choice and can be accomplished with good results. In our experience over a period of more than 20 years, earlier date of operation, young age (<6 months), dysplastic left atrioventricular valve, and coexisting coarctation were incremental risk factors for hospital death. The presence of a previously placed pulmonary artery band did not alter the outcome of repair. The reconstructed atrioventricular valve shows a good and long-lasting performance.

Age Factors↗