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Biomedical subjects

E G Hahn

Publications and source records attributed to E G Hahn.

At least 181 records · Page 10Linked to original sources
PubMed2000

Role of gastric acid secretion in progression of acute gastric erosions induced by ischemia-reperfusion into gastric ulcers.

Ischemia followed by reperfusion is known to produce gastric lesions due to oxidative stress, but the role of gastric H(+) secretion in the formation of this mucosal injury remains unknown. We studied alterations in gastric acid secretion and gastric histamine content, as well as the expression of histidine-decarboxylase and interleukin-1beta during the mucosal recovery from ischemia-reperfusion erosions. Gastric secretion was studied in rats (series A) with gastric fistula before, during and after the ischemia induced by clamping of celiac artery for 0.5 h followed by reperfusion in animals pretreated with vehicle (saline), omeprazole, a proton pump inhibitor, or ranitidine, a histamine (H(2)) receptor antagonist. In series B, the animals were submitted to 0.5 h of ischemia followed by 1 h of reperfusion and then anesthetized at 0, 3, 12 and 24 h or 3, 5, 10 or 15 days after the end of ischemia-reperfusion to determine gastric blood flow by H(2)-gas clearance technique, area of gastric lesions, plasma gastrin and interleukin-1beta levels, histamine content by radioimmunoassay (RIA) and expression of histidine-decarboxylase and interleukin-1beta mRNA by reverse transcription polymerase chain reaction. Clamping of celiac artery caused cessation of gastric blood flow and almost complete suppression of basal gastric acid secretion (series A) that returned gradually to the control value at day 3 after ischemia-reperfusion, accompanied by the rise in plasma gastrin levels, pronounced expression of histidine-decarboxylase mRNA and increased mucosal histamine content. Ischemia, followed by 1 h of reperfusion, produced gastric erosions (series B) that reached maximum at 12 h, but then declined at 24 h. These erosions progressed at day 3 into deeper ulcers whose area declined progressively within the next 5-15 days. The gastric blood ceased to flow (series B) during 30 min of clamping and was reduced throughout the period of healing of acute erosions, being accompanied by a gradual rise in mucosal interleukin-1beta mRNA content and in plasma interleukin-1beta levels. Treatment with omeprazole or ranitidine, which completely suppressed gastric acid secretion and significantly raised plasma gastrin level, greatly reduced the formation of erosive lesions preventing the progression of these lesions to chronic gastric ulcers, and this was accompanied by the rise in gastric blood flow and plasma gastrin levels and the significant attenuation of plasma interleukin-1beta levels. The ranitidine and omeprazole-induced suppression of ischemia-reperfusion erosions were abolished by the instillation of exogenous 0.2 N HCl into the stomach of these rats. The histidine-decarboxylase was faintly expressed in the intact gastric mucosa, but strongly upregulated during mucosal recovery from the damage induced by ischemia-reperfusion. We conclude that following ischemia-reperfusion: (1) gastric acid secretion, gastric microcirculation and histamine production markedly decline, while interleukin-1beta release significantly increases, probably playing an important role in the progression of acute lesions into chronic gastric ulcerations; (2) the suppression of gastric acid secretion by omeprazole and ranitidine, that induces hypergastrinemia, prevents the progression of gastric erosions into ulcers; and (3) the addition of exogenous acid restores the progression of the acute lesions into gastric ulcers, indicating that gastric acid plays a key role in ulcerogenesis induced by ischemia-reperfusion.

Acute Disease↗
PubMed2000

[Retroperitoneal desmoid tumor with kidney failure in familial adenomatous polyposis].

HISTORY AND FINDINGS: A 39-year-old man was hospitalized because of continually rising urinary creatinine and blood urea nitrogen concentration. He was known to have familial adenomatous polyposis (FAP), first diagnosed 18 years previously and re-Physical examination was unremarkable except for pain on percussion over both kidney regions. There was a well-healed laparotomy scar. INVESTIGATIONS: Ultrasound revealed chronic bilateral obstructive renal disease, grade II-III, and computed tomography showed a conglomerate retroperitoneal tumour with obstruction of both ureters at the level of the lower pelvis. This tumour had first been noted first 3 years after the colectomy when the patient complained of abdominal pain. It had been identified histologically as a nonresectable retroperitoneal desmoid tumour. TREATMENT AND COURSE: An external fistula was made, relieving the renal retention. To suppress growth of the desmoid tumour Sulindac, a nonsteroid anti-inflammatory drug, was administered. Genetic molecular analysis revealed a germ line defect in codon 1690 of the APC gene. It is intended to examine other members of the family for the presence of this defect. CONCLUSION: Desmoid tumours are more common in persons with FAP and are among the most frequent extracolic causes of their death. Treatment options are critically analysed.

Adenomatous Polyposis Coli↗
PubMed2000

Clinical evaluation of contrast-enhanced color Doppler sonography in the differential diagnosis of liver tumors.

PURPOSE: We investigated the value of contrast-enhanced color Doppler sonography in the differential diagnosis of liver tumors. METHODS: We prospectively examined 105 focal liver lesions in 100 patients by real-time gray-scale sonography, color Doppler sonography, and contrast-enhanced color Doppler sonography with galactose-based microbubbles (SH U 508A; Levovist). The final diagnoses of the liver lesions as confirmed by pathology or additional imaging techniques were 31 metastases, 25 hemangiomas, 19 hepatocellular carcinomas, 19 focal nodular hyperplasias, 2 cholangiocellular carcinomas, and 9 other lesions. RESULTS: Vascularity could be detected in 43 (41%) of the 105 lesions by conventional color Doppler sonography compared to 67 (64%) by contrast-enhanced color Doppler sonography. Contrast-enhanced color Doppler sonography identified moderate or extensive vascularity in all 19 focal nodular hyperplasias, moderate or extensive vascularity in 16 hepatocellular carcinomas and both cholangiocellular carcinomas, and no or minor vascularity in all but 3 hemangioma. The combination of gray-scale, conventional color Doppler, and contrast-enhanced color Doppler sonography led to the correct diagnosis in 81% of cases (85 of 105), compared to 57% (60/105) for gray-scale and conventional color Doppler sonography and 31% (33/105) for gray-scale sonography alone. CONCLUSIONS: Contrast-enhanced color Doppler sonography improves the detection of tumor vascularity and is useful in the differential diagnosis of liver lesions.

Confidence Intervals↗
PubMed2000

Microsatellite instability in colorectal adenomas: relevance and clinical importance.

A number of investigations have recently been published on the role of microsatellite instability (MSI) in the process of colorectal carcinogenesis. The data concerning colorectal adenomas are difficult to compare (due to differences in the tumor collection, selection and number of analyzed loci, definition of high and low instability and histological types), and this review therefore examines the significance of the results of these publications. We then discuss the extent to which MSI and its effects on the integrity of the genome are early or late events in the malignant transformation, and which clinicopathological features are presented by MSI-positive adenomas. Finally, we consider the clinical importance of microsatellite status for the diagnosis of hereditary nonpolyposis colorectal cancer and the possibility of preventing adenomas and carcinomas by nonsteroidal anti-inflammatory drugs.

Adenoma↗
PubMed2000

An oral endothelin-A receptor antagonist blocks collagen synthesis and deposition in advanced rat liver fibrosis.

BACKGROUND & AIMS: Endothelin 1 induces contraction, proliferation, and collagen synthesis of hepatic stellate cells in vitro, which may be mediated via the endothelin A receptor. It is unknown if specific blockade of the endothelin A receptor inhibits hepatic fibrosis in vivo. METHODS: Groups of 10-20 rats with bile duct occlusion were treated with the nonpeptide endothelin-A receptor antagonist LU 135252 at 80 mg. kg(-1). day(-1) from week 1-6 or from week 4-6, or with LU at 10 mg. kg(-1). day(-1) from week 1-6. Animals with bile duct occlusion alone and sham-operated rats without or with LU at 80 mg. kg(-1). day(-1) over 6 weeks served as controls. After 6 weeks, parameters of fibrogenesis were determined. RESULTS: LU treatment led to improved histology, paralleled by a dose-dependence up to 60% reduction of liver collagen, even when administered at an advanced fibrosis stage. This was accompanied by a decreased messenger RNA of hepatic procollagen alpha1(I) and tissue inhibitor of metalloproteinase 1, 2 major effectors of fibrosis, and of serum procollagen type III, a surrogate marker of liver fibrogenesis. CONCLUSIONS: Selective endothelin-A receptor blockade can dramatically reduce collagen accumulation in rat secondary biliary fibrosis, a model refractory to most potential antifibrotic agents. Endothelin-A receptor antagonists are promising antifibrotic agents in chronic liver disease.

Administration, Oral↗
PubMed2000

Chemical, pharmacological and clinical profile of the East Asian medical plant Centella asiatica.

Centella asiatica is a medicinal plant that has been in use since prehistoric times. Its active constituents include pentacyclic triterpene derivatives. Studies have been conducted in particular to investigate the madecassosides and asiaticosides. In common with most traditional phytotherapeutic agents, Centella asiatica is used in folk medicine to treat a wide range of indications. In contrast to other medicinal plants, however, Centella asiatica has been subjected to quite extensive experimental and clinical investigations. Studies done in accordance with standardized scientific criteria have shown it to have a positive effect in the treatment of venous insufficiency and striae gravidarum. Centella asiatica also appears to be effective in the treatment of wound healing disturbances. At the present time, clinical studies aimed at investigating the sedative, analgesic, antidepressive, antimicrobial, antiviral and immunomodulatory effects that have been demonstrated experimentally, are still lacking. However, the therapeutic potential of this plant in terms of its efficacy and versatility is such that further detailed research would appear worthwhile.

Apiaceae↗
PubMed2000

Parameters of microsomal and cytosolic liver function but not of liver perfusion predict portal vein velocity in noncirrhotic patients with chronic hepatitis C.

Our aim was to compare color-coded Doppler sonography (CCDS) and quantitative testing of liver function (QTLF) in patients with chronic hepatitis C. In all, 74 patients with chronic hepatitis C and mild fibrosis underwent QTLF, which included aminopyrine breath test (ABT), galactose elimination capacity (GEC), sorbitol clearance (SC), and indocyanine green clearance (ICG). Hepatic artery velocity and resistance index (HA-V, HA-RI) as well as portal vein velocity (PV-V) were measured by CCDS. ABT, GEC, and PV-V were significantly reduced, whereas SC1, ICG, HA-V, and HA-RI showed normal levels. There was a significant correlation between reduction in PV-V only with GEC and ABT. QTLF did not correlate with HA-V and HA-RI. In conclusion, in hepatitis C patients with liver fibrosis, ABT and GEC are decreased significantly, which was paralleled by a reduction of PV-V. Unexpectedly SC1 and ICG, the classical hepatic perfusion parameters, do not correlate with the parameters measured by CCDS.

Aged↗
PubMed2000

Eradication of H. pylori with pantoprazole, clarithromycin, and metronidazole in duodenal ulcer patients: a head-to-head comparison between two regimens of different duration.

BACKGROUND: The study was conducted to compare the efficacy and tolerability of two pantoprazole-based triple therapies of different length in the eradication of H. pylori. METHODS: In this double-blind, multicenter parallel group comparison, H. pylori-positive patients were randomly assigned to either the PCM-7 group (7 days of pantoprazole 40 mg bid, clarithromycin 500 mg bid, metronidazole 500 mg bid) or the PCM-14 m group (modified 14 day therapy of the same regimen with metronidazole only given for 10 days due to labeling reasons). H. pylori status was determined by urease test, histology, culture, and 13C-urea breath test. Treatment outcome was assessed 6 weeks after intake of the last study medication. RESULTS: The following eradication rates were achieved: for PCM-7 in the MITT population 83% (89/107), in the PP population 84% (81/97); for PCM-14 m in MITT 87% (92/106), in PP 88% (91/104). Ulcer healing rates were: for PCM-7 in MITT population 99% (106/107), in the PP population 99% (96/97); for PCM-14 m in MITT 99% (105/106), in PP 99% (103/104). Gastrointestinal symptoms and gastritis scores decreased in both treatment groups. Equivalence of treatment regimens could be proven for all populations. In total, 64 patients reported adverse events. Five serious adverse events occurred, all unrelated to the study medication. CONCLUSION: The two pantoprazole-based triple therapies tested in this study are equally effective in H. pylori eradication, ulcer healing and relief from ulcer pain. It is concluded that 7 days of triple therapy are generally sufficient.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2000

Mucosal production of antigastric autoantibodies in Helicobacter pylori gastritis.

BACKGROUND: Apart form bacterial virulence factors of Helicobacter pylori, certain host factors influence the pathogenesis of H. pylori gastritis. In particular, antigastric autoantibodies that are detectable in the sera of a substantial proportion of H. pylori were shown to correlate with the development of gastric atrophy. The aim of this study was to analyze the possible antigastric autoimmune response in H. pylori gastritis at the site where the action is, i.e. , in the gastric mucosa. MATERIAL AND METHODS: Gastric biopsy specimens from antrum and corpus mucosa of 24 H. pylori-infected and of 33 noninfected patients were cultured for 3 days, and tissue culture supernatants were analyzed for the amount of locally produced IgA and IgG. Antigastric autoantibodies were screened in the sera and in the supernatants by means of immunohistochemistry. RESULTS: The infected patients had significantly higher concentrations of locally produced IgA, whereas the IgG concentrations were virtually the same in infected and noninfected patients. IgG or IgA antigastric autoantibodies, or both, were detectable only in the sera (38%) and supernatants (17%) of infected patients. Interestingly, the patient with the strongest local autoimmune response showed body-predominant H. pylori gastritis, with destruction of gastric glands and atrophy of the body mucosa. CONCLUSIONS: These results demonstrate that antigastric autoimmune reactions are detectable at the site of the disease and might be relevant for the pathogenesis of gastric mucosa atrophy in H. pylori gastritis.

Adult↗