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Biomedical subjects

E G Hahn

Publications and source records attributed to E G Hahn.

At least 289 records · Page 16Linked to original sources
PubMed1998

Adaptation of gastric mucosa to stress. Effect of ranitidine.

Gastric mucosal adaptation to injury by repeated application of stress is a well known phenomenon. This study was designed to determine the effect of gastric acid inhibition by ranitidine on gastric adaptation to repeated exposures to stress. In this study stress 3.5 h of water immersion and restraint stress (WRS) was provoked once in rats with and without pretreatment of ranitidine (40 mg/kg/s.c.) and gastric adaptation was examined by repeated exposures to 3.5 h of WRS applied every other day for up to 8 days with pretreatment with vehicle (control), with pretreatment with ranitidine (40 mg/kg/s.c.) and with withdrawal of ranitidine prior to the last exposure to WRS. Luminal acidity, mean lesion number, histology and cell proliferation (PCNA-labeling index) were determined and the expression of EGF and TGF alpha was assessed by immunohistochemistry. Pretreatment with ranitidine increased significantly luminal acidity and WRS applied once with ranitidine pretreatment resulted in a significant decrease of number of lesions. Gastric mucosa adapted to repeated WRS did show a reduction in the mean lesion number by about 60% as compared to that induced by WRS applied once. About 3 fold increase in the expression of EGF was observed in the group adapted to repeated WRS. Expression of TGF alpha was not significantly different from that in intact rats. We conclude that gastric adaptation to stress leads to a decrease in gastric lesions and to an increase in expression of EGF. Pretreatment with ranitidine that induces achlorchydria results in additional reduction in the number of stress lesions.

Adaptation, Physiological↗
PubMed1998

[Enteral nutrition in acute Crohn disease].

High-dose corticosteroids remain the gold standard of therapy in acute Crohn's disease, but is associated with a variety of side effects. Nutritional therapy could be an interesting alternative, but corticosteroids are meant to be significantly superior according to efficacy. Published studies, identified by references, MEDLINE and meta-analysis, were evaluated for efficacy of nutritional therapy in acute Crohn's disease. In 18 evaluable of 38 identified publications, 571 patients were treated with nutritional therapy: 295 received elemental diet, 214 oligopeptide diet and 62 polymeric diet. Remission rates were 60%, 55% and 66% respectively. However, only intention-to-treat-analysis was performed in all the studies. When correcting for patients who really were treated with nutritional therapy, remission rates were substantially better: 73%, 70% and 67% respectively, thus comparable with that of corticosteroids. Positive predictors for successful treatment were stenosing disease and low ESR. Remission seems to last as long as after corticosteroid treatment, when a reinduction diet is performed. Negative aspects of nutritional therapy are poor tolerance and higher costs. Perspectives for the future aim on broadening of indications, improving acceptance (by adjuvant instead of exclusive nutrition, or new flavors) and efficacy by modification of compounds (such as glutamine, omega-3 fatty acids or trace elements) or combination with other therapeutic agents (e.g., mesalamine).

Acute Disease↗
PubMed1997

[Auto-CPAP treatment in obstructive sleep apnea syndrome: a prospective randomized study during initiation of treatment].

OBJECTIVE: The efficacy and acceptance of self-regulated continuous positive airway pressure (auto-CPAP) ventilation was compared with conventional CPAP administration in the treatment of patients with obstructive sleep apnoea. PATIENTS AND METHODS: Using a cross-over design, under polysomnographic monitoring in a sleep laboratory, 25 patients with obstructive sleep apnoea underwent conventional CPAP or auto-CPAP treatment. Using a questionnaire, patients gave their assessment of its acceptability and efficacy after each treatment session. RESULTS: The mean pressure during treatment was the same in the two groups (7.2 +/- 1.9 versus 7.1 +/- 1.9 mbar; no significant difference). Maximal pressure during auto-CPAP averaged 3.7 +/- 2.1 mbar higher than during conventional CPAP ventilation. The mean apnoea-hypopnoea index (AHI) during auto-CPAP, 4.4 +/- 4.3 mbar, during auto-CPAP was significantly higher than during conventional CPAP treatment (2.8 +/- 2.8 mbar; P = 0.044). In eight patients on auto-CPAP an AHI of 5 or less could not be reached, while an AHI of 5 or less was obtained in all but three patients under conventional CPAP. In a subgroup of 17 patients, in whom a reduction of AHI to at most 5 was achieved with both conventional and auto-CPAP, analysis of sleep pattern and of arousals was similar with the two forms of ventilation. Several patients reported that with auto-CPAP falling in sleep was more difficult and they slept less well. None of the patients preferred auto-CPAP. CONCLUSION: By means of the auto-CPAP neither a pressure reduction nor an improvement in compliance could be achieved. Therapeutic effectiveness was significantly less as with conventional CPAP therapy.

Adult↗
PubMed1997

[Differential diagnosis of acute testicular pain using color-coded duplex ultrasonography: difference between testicular torsion and epididymitis].

OBJECTIVE: To assess retrospectively the accuracy of colour-coded duplex sonography (CCDS) in distinguishing testicular torsion from epididymitis as the cause of acute testicular pain. PATIENTS AND METHODS: The results of CCDS were analysed for all 81 patients (mean age 27.2 years [6 weeks to 60 years]), admitted between 1.1.1995 and 30.6.1996 with the diagnosis of acute testicular pain. Testicular torsion was diagnosed when CCDS failed to detect perfusion in one testis. Regular arterial and venous perfusion of both testes excluded torsion. Epididymitis was diagnosed when hyperperfusion of the epididymis was demonstrated by CCDS. RESULTS: 20 of 22 cases of torsion, subsequently diagnosed at surgery, had been correctly diagnosed by CCDS (sensitivity 90.9%, specificity 98.3%). 55 patients had epididymitis, confirmed by the clinical course and follow-up having excluded torsion. Other causes (trauma, tumour, inguinal hernia) were found in the remainder of patients. CONCLUSION: With a positive predictive value of 95.2% and a negative one of 96.6% CCDS is a highly suitable method for recognizing or excluding testicular torsion and thus clarifying the cause of acute testicular pain.

Acute Disease↗
PubMed1997

[Leiomyosarcoma of the esophagus. Clinical aspects, diagnosis and therapy based on an individual case].

Leiomyosarcomas of the esophagus are rare tumors of mesenchymal origin. Apropos of a case we present clinicopathological features, diagnostic procedures and management of this seldom tumor of the esophagus. Primary gastrointestinal sarcomas cause less than 0.5% of all esophageal malign tumors, and present in ca. 5% as esophageal leiomyosarcomas. The most frequent incidence ranges between the fourth and fifth decade of life. The tumors originate from the muscular layers of the esophageal wall and are localized predominantly in the middle and distal third of the esophagus. Dysphagia is the most important and leading symptom although it presents late in the course of the illness. Endosonography is at the time the most accurate method to establish the tumor size. Differentiation between leiomyoma and leiomyosarcoma is only possible by histopathological examination and may be difficult in certain cases. Histopathological grading of the tumors as low- and high-grade sarcomas in dependence of the number of mitosis affects predominantly the prognosis of these patients. Differential diagnosis includes spindle cell carcinoma and carcinosarcoma of the esophagus. The most effective therapy consists in the complete operative removal of the tumor, in these cases five years survival rates of 30 to 40% are achieved, strongly influenced by tumor differentiation and size.

Adult↗
PubMed1997

Melatonin affords protection against gastric lesions induced by ischemia-reperfusion possibly due to its antioxidant and mucosal microcirculatory effects.

Melatonin, a pineal hormone, is known to scavenge oxygen free radicals and to be present in the gut but little is known about its role in the protection of gastric mucosa against the damage accompanied by a marked increase in these radicals. This study was designed to determine the effects of melatonin on the formation of acute gastric lesions induced by ischemia-reperfusion and, for comparison, by a topical irritant such as 100% ethanol. It was found that pretreatment with melatonin at a dose of 5 mg/kg given intragastrically reduced significantly gastric lesions induced by ischemia-reperfusion and this was accompanied by a reduction in free radicals in the blood and by attenuation of the fall in gastric blood flow. In contrast, melatonin failed to affect acute gastric lesions induced by 100% ethanol. We conclude that melatonin is capable of protecting gastric mucosa from the damage caused by ischemia-reperfusion and that this action is mediated, at least in part, by limitation of the generation of free radicals and by attenuation of the fall in gastric blood flow.

Animals↗
PubMed1997

Role of spasmolytic polypeptide in healing of stress-induced gastric lesions in rats.

Stress is known to induce gastric ulcerations but the mechanism of their healing has been little studied. This paper describes the studies on mucosal expression and the effect on ulcer healing of spasmolytic peptide (SP), one of the members of the trefoil peptide family. Gastric ulcerations were induced in rats by the exposition to 3.5 h of water immersion and restraint stress. It was found that the number of these lesions gradually declined at 4, 8 and 12 h after stress and this spontaneous healing was significantly accelerated by s.c. infusion of human recombinant SP in a constant dose of 50 micrograms kg-1 h-1. The healing of the stress-induced ulcerations was accompanied by a gradual restoration of gastric mucosal blood flow and the decrease in gastric acid and pepsin secretion towards the normal values. The expression of SP in rats (rSP) was detected by RT-PCR in the intact mucosa and during all tested time periods reaching a peak at 4 h after the stress. Immunostaining for rSP in the intact mucosa was confined to the mucous neck cells, but following the exposure to stress it was significantly enhanced and occurred also in the cells of the basal region of gastric glands, reaching a peak at 4 h after the stress. We conclude that SP plays an important role in healing of stress-induced gastric lesions possibly by the acceleration of the mucosal repair, the enhancement of mucosal blood flow and the inhibition of gastric secretion.

Animals↗
PubMed1997

Thyroid autonomy with color-coded image-directed Doppler sonography: internal hypervascularization for the recognition of autonomous adenomas.

In a prospective study, we assessed the possibility of recognizing autonomous adenomas of the thyroid with color-coded image-directed Doppler sonography using internal hypervascularization in thyroid nodules for identification. Fifty-three patients with thyroid nodules underwent additional CCDS examination and nuclear scintigraphy (reference). Of 29 patients having autonomous adenomas, 28 patients presented internal hypervascularization in their nodules resulting in a sensitivity of 96% and a specificity was 75%. Interestingly CCDS detected six adenomas in patients showing normal laboratory data (bTSH, TT3, FT4). CCDS could be used to exclude focal adenomas with a negative predictive value of 94%. The positive predictive value for adenoma was 82%.

Adenoma↗
PubMed1997

Urinary sodium balance in patients with cirrhosis: relationship to quantitative parameters of liver function.

The relationship between the impairment in hepatic and renal function in cirrhosis has not been well established. This study investigated urinary sodium excretion in comparison with quantitative parameters of liver function in 75 patients with various degrees of cirrhosis kept on a constant salt diet of 120 mmol/d for 5 days before the start of the study. The aminopyrine breath test (ABT), indocyanine green (ICG) elimination, galactose elimination capacity (GEC), and hepatic sorbitol elimination (HSE) served as quantitative parameters of liver function. Results for the quantitative tests were compared with those for the Child-Pugh score. Urinary sodium excretion showed a significant nonlinear relationship to ABT (r = .70; P < .0001). Less-significant correlations were observed for ICG (r = .60), the Child-Pugh score (r = -.57), GEC (r = .44), and HSE (r = .34). Because a number of significant correlations were observed between the different liver function tests, multivariate analysis was used to further elucidate the relationship between hepatic function and sodium excretion. Only one independent predictor of urinary sodium excretion could be identified, and that was the ABT (P < .02). More than half of the nonascitic patients showed a urinary sodium excretion of less than 80% of dietary sodium intake, indicating impaired renal sodium handling in preascitic cirrhosis. Based on the 95% confidence interval (CI) for ABT of nonascitic patients with normal (mean ABT 0.56% dose x kg/mmol CO2; 95% CI: 0.44 to 0.69) and reduced urinary sodium excretion (mean ABT 0.26% dose x kg/mmol CO2; 95% CI: 0.18 to 0.35), a threshold level of ABT of about 0.4 (% dose x kg/mmol CO2) for conservation of normal urinary sodium excretion in cirrhosis can be defined. This ABT value reflects an approximate 50% reduction in function compared with the mean of cirrhotic patients with normal liver and kidney function (0.81% dose x kg/mmol CO2). The presence of ascites was also associated with a reduction in ABT to below 0.4 (% dose x kg/mmol CO2), while, for all other parameters, either the cut-off point was close to the lower limit of normal or no cut-off level could be detected. In conclusion, the results of the present study provide further evidence that the impairment in urinary sodium excretion in cirrhosis is related to hepatic function. The data suggest a nonlinear relationship. Because ABT has been shown to reflect functional hepatocellular mass, the occurrence of sodium retention and ascites appears to be related to a threshold of an approximate 50% reduction in functional liver cell mass.

Adult↗
PubMed1997

Risk of invasive carcinoma in colorectal adenomas assessed by size and site.

BACKGROUND: The risk of invasive carcinoma developing in colorectal adenomas is influenced by a number of characteristics of both patients and adenomas, and the composition of the sample analysed. PATIENTS AND METHODS: Between 1978 and 1993 more than 20,000 polyps were prospectively documented at the Erlangen Registry of Colorectal Polyps, and analysed statistically by logistic regression. RESULTS: The size of the adenomas proved to be the most important factor for adenomas equal to or larger than 15 mm as compared with smaller lesions. In 5,137 diminutive adenomas (< or = 5 mm) invasive carcinoma was never found. Adenomas in the right-sided colon had a lower risk than those in the left colon or rectum, but with increasing adenoma size, the malignancy rate showed a right-sided shift. In adenomas of up to 36 mm in diameter, invasive carcinoma was found more often when they were located in the rectum or left colon while adenomas larger than 36 mm were more likely to harbour invasive carcinoma when located in the right or left colon rather than in the rectum. CONCLUSIONS: A multivariate analysis of 11,380 adenomas detected at the first total colonoscopy showed that the factors size and site, both of which can be assessed by endoscopic inspection alone, were found to enable a statistically and clinically adequate assessment of the malignancy risk.

Adenoma↗
PubMed1997

[Long-term outcome of continence function after ileo-anal pouch reconstruction].

An important aim of proctocolectomy with ileal pouch-anal anastomosis (IPAA) is to maintain anal continence. Anal sphincter disruption during IPAA is felt to play an important role in loss of continence, which is described in up to 30% of the treated patients in the early postoperative period. Although sphincter function recovers gradually after surgery, some patients stay incontinent. In our investigation of possible parameters involved in preservation of continence after this operative procedure, we focused on changes in anal manometry. We compared these findings with the functional results obtained by questioning the patients and physical examination. Anal manometry was performed with a low-compliance hydraulic perfusion system. All patients underwent a J-pouch procedure with a short rectal cuff for ileoanal reconstruction. We examined 25 patients, 13 underwent operation for the treatment of ulcerative colitis, 12 because of adenomatous polyposis. In the colitis and polyposis group, 28% of the patients reported events of soiling. Three patients (12%) were incontinent. The remaining 15 patients were completely continent. The median time after operation was 58 months, ranging from 12 to 96 months. Comparing the results of anal manometry with standard values of ten age- and gender-matched healthy volunteers, it was found that there was a significant increase in the threshold of balloon awareness and urge to defecate. These sensations were sometimes elicited by pouch contractions. Median pouch-compliance was also clearly elevated in comparison to rectal compliance (P < 0.005). Inhibitory reflexes during balloon inflation could not be evoked in any of the patients. Comparing continent with incontinent patients there were significant differences in balloon awareness, urge to defecate, and stool frequency (P < 0.01, P < 0.01 and P < 0.001, respectively). But in contrast to other publications, we could not find significant differences in anal sphincter length, resting and squeezing, anal canal pressure. Pouch compliance was lowered in incontinent patients and negatively correlated with stool frequency (P < 0.001, r = -0.82). In conclusion, our study indicates that anal sphincter resting pressure alone is not a crucial factor in continence preservation in the long-term after total proctocolectomy and IPAA. Poor pouch-compliance and concomitant higher stool frequencies seem to be related to incontinence in this patient group.

Adenomatous Polyposis Coli↗
PubMed1997

Benefits and risks of needle-knife papillotomy.

BACKGROUND: The objective of the present investigation was to assess the risks and benefits of pre-cutting with the needle knife at the papilla of Vater and to compare the findings with the results of classic endoscopic sphincterotomy. METHODS: From January 1973 to December 1993, 2752 endoscopic cutting procedures-biliary or pancreatic sphincterotomy (EST) or needle-knife papillotomy (NKP)-were performed. Since 1981 the pre-cut technique with the needle knife has been used alone or in combination with standard sphincterotomy. Indications, success, and complications of NKP and EST were analyzed retrospectively. To demonstrate changes in indications and technique, the study period was divided into two time periods: period A, 1981 to 1987; and period B, 1988 to 1993. RESULTS: Between 1981 and 1993, diagnostic or therapeutic access to the biliary or pancreatic duct system was attempted in 2105 patients by means of EST or related procedures (period A 1093 patients; period B 1012 patients). The overall success rate was 95.1% (2001 of 2105). In 694 of 2105 cases (33.0%) an EST was not possible or not attempted and an NKP was performed (period A 31.9%; period B 34.1%). This was successful in 590 of 694 cases (85.2%). The rate of NKP in relation to EST varied depending on the different indications for EST: 22.8% NKP in classic indications like choledocholithiasis and over 40% in newer indications such as chronic pancreatitis. In these novel indications NKP alone was often sufficient, and EST to complete the procedure was not necessary (151 patients). In period B, NKP (63 patients) and EST (23 patients) were also used to achieve endoscopic retrograde imaging of the biliary or pancreatic duct system when primary cannulation was not possible. Visualization was achieved in 81.4% (70 of 86) and pathologic findings were noted in 68.6% (59 of 86). The total complication rate of primary EST was 6.8% (96 of 1411) and 7.3% (51 of 694) for all procedures in which NKP was involved (NS). In period B the complication rate was 4.6% for NKP without subsequent EST and 7.6% for NKP in combination with EST. Compared with the complication rate of primary standard EST (6.1%) there was no statistically significant difference. CONCLUSIONS: Needle-knife papillotomy increases the success of diagnostic and therapeutic procedures at the papilla of Vater. This pre-cut technique is safe and does not increase the overall complication risk of sphincterotomy.

Aged↗
PubMed1997

Botulinum toxin injection as a diagnostic tool for verification of sphincter of Oddi dysfunction causing recurrent pancreatitis.

Sphincter of Oddi dyskinesia (SOD) is among the less frequent causes of acute recurrent pancreatitis. We report on a patient with frequent pain attacks accompanied by pancreatic enzyme elevation, in whom a transitory decrease of the SO pressure following endoscopic botulinus toxin injection was a diagnostic clue for SOD. The patient's symptoms resolved for 4 months, after which time recurrent symptoms paralleled the reoccurrence of the elevated SO pressure. Endoscopic sphincterotomy of the biliary sphincter relieved her symptoms for the subsequent follow-up period which is now 10 months.

Acute Disease↗
PubMed1997

Invasive carcinoma in colorectal adenomas: multivariate analysis of patient and adenoma characteristics.

BACKGROUND AND STUDY AIMS: The risk of invasive carcinoma developing in colorectal adenomas is influenced by a number of characteristics, relating both to the patients and to the adenomas, and by the composition of the sample analyzed. The aim of the present study was use a multivariate analysis to investigate the risk of invasive carcinoma in endoscopically and surgically removed adenomas. PATIENTS AND METHODS: Between 1978 and 1993, more than 20,000 polyps were prospectively documented at the Erlangen Registry of Colorectal Polyps. A multivariate analysis of 11,188 adenomas detected at the first total colonoscopy was carried out in order to investigate the risks associated with size and site--both of which can be assessed by endoscopic inspection alone- and the extent to which these may be modified by other patient and adenoma characteristics, with an influence on the risk of invasive carcinoma in colorectal adenomas. RESULTS: The size of the adenoma proved to be the most important influencing factor. Invasive carcinoma was never found in 5027 small adenomas (< or = 5 mm). Adenomas in the right colon had a lower risk than those in the left colon or rectum. But with increasing adenoma size, the malignancy rate showed a right-sided shift, with a significant interactive effect of size and right-sided location. However, the risk determined by the size and site of the adenoma was significantly modified by a number of patient and adenoma characteristics, including histological type, presence of multiple adenomas, and patient age and sex. CONCLUSIONS: The risk of invasive carcinoma in colorectal adenomas can only be adequately described by a complex model of the interactive effects of patient and adenoma characteristics on the main factors of size and site.

Adenoma↗
PubMed1997

Importance of nitric oxide and capsaicin-sensitive afferent nerves in healing of stress lesions induced by epidermal growth factor.

Epidermal growth factor (EGF) is a potent mitogen implicated in gastroprotection and ulcer healing, but its possible interaction with nitric oxide (NO) and sensory nerves on healing after acute gastric damage has not been assessed. We examined the effects of topical application of a small dose (0.5 mg/kg) of capsaicin to stimulate sensory nerves and a larger parenteral dose of capsaicin (125 mg/kg s.c.) to deactivate these neurons or the effect of systemic administration of NG-nitro-L-arginine methyl ester (L-NAME) (20 mg/kg i.v.) to suppress NO synthase on healing of gastric lesions induced by 3.5 h of water immersion and restraint stress (WRS) in rats without or with EGF administration. Rats were sacrificed at 0, 6, 12, or 24 h after WRS and the gastric blood flow (GBF) was measured by the H2 gas clearance technique. Exposure to WRS produced many gastric lesions, with a marked decrease in GBF, but at 12 h these lesions started to heal and the lesion number was reduced by 75% after 24 h. This was accompanied by progressive increase in the GBF and an increase in expression of EGF mRNA in gastric mucosa, as detected by RT-PCR. Pretreatment with L-NAME or functional ablation of sensory nerves by capsaicin significantly delayed the healing of WRS lesions and accompanying hyperemia. In contrast, pretreatment with EGF (100 micrograms/kg s.c.) or glyceryl trinitrate (10 mg/kg i.g.), a donor of NO, or stimulation of sensory nerves by topical capsaicin significantly enhanced the healing of these lesions and increased the GBF. The acceleration of the healing and accompanying hyperemia induced by EGF at 12 h after WRS were completely reversed in rats pretreated with L-NAME or in those with capsaicin denervation. Addition of L-arginine but not D-arginine to L-NAME restored the healing of stress lesions and gastric hyperemia induced by this peptide. Removal of salivary glands, which reduced luminal content of EGF and DNA synthesis by about fourfold compared to rats with intact glands, produced a significant delay in healing, and this was further aggravated by capsaicin denervation. We conclude that EGF, sensory nerves, and NO play an important role in the healing of gastric mucosa from lesions induced by stress and that sensory nerves and NO appear to interact with EGF in the mechanism of mucosal recovery from stress lesions.

Animals↗
PubMed1997

The role of melatonin and L-tryptophan in prevention of acute gastric lesions induced by stress, ethanol, ischemia, and aspirin.

Melatonin, a pineal hormone, synthesized from L-tryptophan, is known to exist in the gut and to scavenge oxygen free radicals but its role in gastroprotection against acute lesions induced by various strong irritants has been little studied. In this study, we determined the effects of melatonin and L-tryptophan on gastric secretion and the formation of acute gastric lesions induced by absolute ethanol, acidified aspirin (ASA), stress, and ischemia-reperfusion (I/R). Area of gastric lesions was determined by planimetry, gastric blood flow (GBF) was measured using a H2-gas clearance technique, and blood was withdrawn for the measurement of free radicals, plasma gastrin, and melatonin concentration by specific radioimmunoassay. Intragastric (i.g.) administration of melatonin (2.5-10 mg/kg) or L-tryptophan (25-200 mg/kg) failed to affect gastric lesions by ethanol and ASA but dose-dependently reduced the lesions provoked by stress and I/R; this protective effect was accompanied by a significant rise in plasma melatonin level, GBF, and DNA synthesis and by a marked fall in blood free radicals. L-tryptophan, which significantly elevated the plasma melatonin by about 3-5-fold, also reduced the stress and I/R-induced lesions and blood levels of free radicals, while increasing the GBF, DNA synthesis, and plasma gastrin levels. Inhibition of mucosal generation of PGE2 by indomethacin abolished the protection and the rise of GBF afforded by melatonin and L-tryptophan, whereas pretreatment with N(G)-nitro-L-arginine (L-NNA), to suppress nitric oxide (NO) synthase, was without any effect. We conclude that melatonin applied exogenously in pharmacological doses and that released by the administration of its precursor, L-tryptophan, protect gastric mucosa from the damage induced by stress and I/R possibly by a mechanism involving the scavenging of free radicals and gastric hyperemia probably mediated by endogenous prostaglandin but not NO.

Acute Disease↗