Search PubMed⌕ Search

Biomedical subjects

T Lingenfelser

Publications and source records attributed to T Lingenfelser.

At least 19 recordsLinked to original sources
PubMed2001

Lower intestinal bleeding.

Lower gastrointestinal tract bleeding is a frequent cause of physician consultations and hospital admissions. Clinical presentation is predictable and significantly influences subsequent patient management. Controversy surrounding diagnosis and treatment of lower gastrointestinal bleeding results from a surprising lack of prospective controlled data. Thus, selection of diagnostic and therapeutic manoeuvres often depends more on local expertise and availability than on an algorithm approach. Advances in endoscopic, radiological and surgical equipment and techniques offer promising new diagnostic and therapeutic modalities, particularly in concerted applications. Outcome studies on the appropriate sequence and linking of these modalities are urgently needed. The present chapter will address clinical presentation, aetiology, diagnosis and treatment of lower gastrointestinal tract bleeding.

Colitis↗
PubMed2001

Gastrointestinal bleeding in the elderly.

Gastrointestinal bleeding in elderly individuals is a frequent cause of consultation with a physician and of hospital admissions. Co-morbidity and greater medication use in this steadily growing patient group influence the clinical course and adversely affect outcome. Clinical presentation is often predictable and guides subsequent patient management. Due to a surprising lack of prospective controlled data in the area of gastrointestinal bleeding, the selection of diagnostic and therapeutic manoeuvres often depends more on local expertise and availability than on an algorithmic approach. Advances in endoscopic, medical, radiological and surgical treatment modalities offer promising new diagnostic and therapeutic tools, particularly in concerted applications. Outcome studies on the appropriate sequence and linking of these modalities are urgently needed. This chapter will address clinical presentation, aetiology, diagnosis and treatment of both upper and lower gastrointestinal bleeding in the elderly.

Aged↗
PubMed2001

Development of a sleeve sensor for measurement of sphincter of Oddi motility.

BACKGROUND AND STUDY AIMS: Unavoidable catheter movement during sphincter of Oddi (SO) manometry can produce considerable variations in the basal pressure, due to movement of the recording sidehole. The sleeve sensor is a perfused channel which records the highest pressure point along its length. The aim of the study was to develop and evaluate a prototype sleeve sensor for SO manometry. MATERIALS AND METHODS: Bench-testing was used to assess the dynamic performance of the sleeve and sidehole assemblies. Recordings were initially made with a standard triple-lumen catheter and then with a purpose-built manometric assembly which had a 15 mm long sleeve sensor. RESULTS: A perfusion rate of 0.04 ml/min gave the best balance between baseline pressure offset and rise rate. Recordings were attempted in nine patients and successfully achieved in four. The sleeve and sidehole recordings of the maximal basal pressure did not differ significantly (mean +/- SEM, 86.1 +/- 26.5 mmHg vs. 90.1 +/- 21.0 mmHg, P = 0.57, r = 0.998). CONCLUSIONS: Unnecessarily high perfusion rates are being used for SO manometry. The sleeve sensor has the potential to monitor SO pressure more reliably than the currently used perfused sidehole method and should enhance the safety of prolonged SO manometry.

Adult↗
PubMed2000

A phase II study of paclitaxel, weekly, 24-hour continous infusion 5-fluorouracil, folinic acid and cisplatin in patients with advanced gastric cancer.

To evaluate the toxicity and efficacy of combination chemotherapy with paclitaxel, cisplatin and 24 h continuous infusion of 5-FU/folinic acid in patients (pts) with unresectable, locally advanced or metastatic gastric adenocarcinoma. Forty-five chemotherapy-naive pts (28 male and 17 female) with a median age of 60 years (range 35-74) were enrolled. 5-FU 2 g/m2 was given weekly over 24 h i.v. preceded by folinic acid 500 mg/m2 as a 2 h infusion. Paclitaxel 175 mg/m2 was administered as a 3 h-infusion on days 1 and 22 and cisplatin 50 mg/m2 as 1 h infusion on days 8 and 29. Six weeks of therapy (days 1, 8, 15, 22, 29, 36) followed by 2 weeks rest were considered one cycle. A median of 3 cycles (range 1-4) were administered to 45 pts assessable for response, survival and toxicity. Five pts (11%) obtained a CR and 18 pts (40%) a PR (ORR 51%; 95% CI: 35.8-66.3%). Responses were achieved in the liver, lymph nodes, lungs and at the site of the primary tumour. Nine pts (20%) had stable disease. Thirteen pts (29%) were considered to have failed treatment, 8 pts (18%) due to progressive disease and 5 pts (11%) who did not receive one complete cycle of therapy due to acute non-haematologic toxicity. The median progression-free and overall survival times were 9 months (range 1-36+) and 14 months (range 2-36+), respectively. Neutropenia WHO III(o)/IV(o) occurred in 7 pts (15%) with only 1 pt having grade IV. Additional non-haematologic WHO III(o)/IV(o) toxicities included nausea/vomiting in 5 (11%), alopecia in 22 (49%), and diarrhoea in 1 patient each (2%). Dose reductions or treatment delays were necessary in 8 pts (17%), mainly due to neutropenia. All pts were treated on an outpatient basis. The combination of paclitaxel, cisplatin and continuously infused 5-FU/folinic acid appears to be a highly active regimen for the treatment of pts with advanced gastric cancer. While the overall acceptable toxicity allows its use in the palliative setting, it may also be an attractive option to be tested for neoadjuvant or adjuvant treatment.

Adenocarcinoma↗
PubMed1999

Effects of duodenal distension on antropyloroduodenal pressures and perception are modified by hyperglycemia.

Marked hyperglycemia (blood glucose approximately 15 mmol/l) affects gastrointestinal motor function and modulates the perception of gastrointestinal sensations. The aims of this study were to evaluate the effects of mild hyperglycemia on the perception of, and motor responses to, duodenal distension. Paired studies were done in nine healthy volunteers, during euglycemia ( approximately 4 mmol/l) and mild hyperglycemia ( approximately 10 mmol/l), in randomized order, using a crossover design. Antropyloroduodenal pressures were recorded with a manometric, sleeve-side hole assembly, and proximal duodenal distensions were performed with a flaccid bag. Intrabag volumes were increased at 4-ml increments from 12 to 48 ml, each distension lasting for 2.5 min and separated by 10 min. Perception of the distensions and sensations of fullness, nausea, and hunger were evaluated. Perceptions of distension (P < 0.001) and fullness (P < 0.05) were greater and hunger less (P < 0.001) during hyperglycemia compared with euglycemia. Proximal duodenal distension stimulated pyloric tone (P < 0.01), isolated pyloric pressure waves (P < 0.01), and duodenal pressure waves (P < 0.01). Compared with euglycemia, hyperglycemia was associated with increases in pyloric tone (P < 0.001), the frequency (P < 0.05) and amplitude (P < 0.01) of isolated pyloric pressure waves, and the frequency of duodenal pressure waves (P < 0.001) in response to duodenal distension. Duodenal compliance was less (P < 0.05) during hyperglycemia compared with euglycemia, but this did not account for the effects of hyperglycemia on perception. We conclude that both the perception of, and stimulation of pyloric and duodenal pressures by, duodenal distension are increased by mild hyperglycemia. These observations are consistent with the concept that the blood glucose concentration plays a role in the regulation of gastrointestinal motility and sensation.

Adult↗
PubMed1998

Effect of programmed endoscopic follow-up examinations on the rebleeding rate of gastric or duodenal peptic ulcers treated by injection therapy: a prospective, randomized controlled trial.

BACKGROUND AND STUDY AIMS: A second-look endoscopy is often performed to evaluate the efficacy of a prior injection therapy in patients with bleeding peptic gastric or duodenal ulcers. Although this strategy is widely established, it does not rely on unequivocal data from controlled studies. In a prospective, randomized, controlled multicenter trial we assessed the effect of programmed endoscopic follow-up examinations with eventual retreatment on the outcome of bleeding ulcers in these patients. PATIENTS AND METHODS: One hundred and five patients with gastric or duodenal peptic ulcers presenting with active (Forrest type I) or recent (Forrest type IIa and IIb) bleeding upon endoscopy within four hours after admission were included in the study. Emergency treatment consisted of the sequential injection of both epinephrine (1:10,000 v/v) and up to 2 ml of fibrin/thrombin around the ulcer base. Fifty-two patients were randomized to receive programmed endoscopic monitoring with eventual retreatment in cases of Forrest type I, IIa, or IIb ulcers beginning within 16-24 hours after the index bleed. Follow-up endoscopies were continued until the macroscopic appearance revealed a Forrest type IIc or III ulcer. Fifty-three patients in the control group were closely monitored, and only received a second endoscopy when there was clinical or biochemical evidence of recurrent bleeding. The groups did not differ with respect to age, sex, site and severity of bleeding. RESULTS: The numbers of patients with recurrent bleeding were similar whether they were endoscopically monitored or not (21% versus 17%, P=0.80 chi-squared test). In addition, there was no statistically significant difference between the two groups with respect to the number of blood units transfused, need for surgical intervention, hospital stay or number of deaths (Mann-Whitney U-test). Improving local ulcer stigmata was not related to a better outcome. CONCLUSIONS: Programmed endoscopic follow-up examinations with eventual retreatment in patients locally injected for an acute or recent hemorrhage from a gastric or duodenal ulcer did not influence their outcome when compared to patients receiving only a second endoscopic intervention upon evidence for recurrent hemorrhage. Scheduled control endoscopies cannot be recommended after an initial successful endoscopic treatment of peptic ulcer bleeding when selection of the patients for second-look endoscopy is directed by the Forrest criteria.

Aged↗
PubMed1998

Effects of nitroglycerin on liquid gastric emptying and antropyloroduodenal motility.

The effects of the nitric oxide donor nitroglycerin on gastric emptying and antropyloroduodenal motility were evaluated in nine healthy male subjects (ages 19-36 yr). Antropyloroduodenal pressures were recorded with a manometric assembly that had nine side holes spanning the antrum and proximal duodenum and a pyloric sleeve sensor; gastric emptying was quantified scintigraphically. In each subject, the emptying of 300 ml of 25% glucose labeled with 99mTc was assessed on two separate days during intravenous infusion of either nitroglycerin (5 micrograms/min in 5% dextrose) or 5% dextrose (control). Studies were performed with the subject in the supine position; blood pressure and heart rate were monitored. Nitroglycerin had no significant effect on blood pressure or heart rate. Nitroglycerin slowed gastric emptying (P < 0.02), and this was associated with greater retention of the drink in the proximal stomach (P < 0.05). In both nitroglycerin and control studies, ingestion of the drink was associated with an increase in the number of isolated pyloric pressure waves (P < 0.05) and antral pressure wave sequences (P < 0.05). Nitroglycerin reduced the number of isolated pyloric pressure waves (P < 0.05), basal pyloric pressure (P < 0.05), and the number of antral pressure wave sequences (P < 0. 05), but not the total number of antral pressure waves. The rate of gastric emptying and the number of isolated pyloric pressure waves were inversely related during control (P = 0.03) and nitroglycerin (P < 0.05) infusions. We conclude that in normal subjects, 1) gastric emptying of 300 ml of 25% glucose is inversely related to the frequency of phasic pyloric pressure waves, and 2) nitroglycerin in a dose of 5 micrograms/min inhibits pyloric motility, alters the organization but not the number of antral pressure waves, and slows gastric emptying and intragastric distribution of 25% glucose.

Adult↗
PubMed1997

Pyloric motor response to central and peripheral nitric oxide in the ferret.

This study has investigated the relative importance of central nervous and peripheral nitroxidergic mechanisms in the control of pyloric motility. In 10 urethane-anaesthetized ferrets, drugs were administered directly to the CNS via a 0.5-mm-diameter cannula inserted into the 4th ventricle, approximately at the obex. Drugs were also given directly to the upper GI tract by close intra-arterial (i.a.) injection at the coeliac axis. Antropyloroduodenal pressures were recorded with a five-channel sleeve/sidehole micromanometric assembly (1.35 x 1.75 mm o.d.), which was introduced via the duodenum. Pyloric motility was stimulated throughout the main part of each study with a continuous i.v. infusion of CCK-8 (30 pmol min-1). This infusion produced an immediate and sustained increase in tonic and phasic pyloric activity, and sustained abolition of antral pressure waves. CCK-8 also induced a duodenal motor response, but this was short-lived (11.4 +/- 7.9 min). Coeliac axis injection of the NO donor S-nitroso-N-acetyl-penicillamine (SNAP) decreased phasic pyloric activity (from 330 +/- 35 to 148 +/- 21 mmHg min-1 after SNAP 5 micrograms, P < 0.01). By comparison central SNAP administration over the same dose range had no effect on CCK-stimulated pyloric motlity. Inhibition of endogenous NO synthase with L-Nitro Arginine Methyl Ester (L-NAME, 100 mg kg-1 close i.a.) caused a marked increase of phase pyloric motor activity from 349 +/- 59 to 1044 +/- 140 mmHg min-1 (P < 0.01). In addition, SNAP caused marked stimulation of pyloric tone from 2.6 +/- 0.5 to 13.1 +/- 2.8 mmHg (P < 0.01). Central nervous administration of L-NAME caused modest enhancement of phasic pyloric activity (248 +/- 31 to 283 +/- 32 mmHg min-1 P < 0.05) and pyloric tone (2.6 +/- 0.5 to 3.7 +/- 0.7 mmHg, P < 0.05). Our data indicate that motor activity of the ferret pylorus is potently modulated by NO released within the upper gut. Additionally, there is potential for modulation of pyloric motility by central nervous system production of NO.

Animals↗
PubMed1996

Effects of glyceryl trinitrate on the pyloric motor response to intraduodenal triglyceride infusion in humans.

The retardation of gastric emptying induced by infusion of triglyceride into the small intestine is associated with suppression of antral pressure waves and stimulation of basal pyloric tone in combination with phasic pressure waves localized to the pylorus. The role of nitric oxide (NO) mechanisms in the control of pyloric motility was evaluated in 12 healthy male subjects (21-43 years), using the NO donor glyceryl trinitrate (GTN). Antropyloric pressures were measured with a manometric assembly incorporating nine sideholes, spanning the antrum and proximal duodenum, and a pyloric sleeve sensor. On separate days, an intraduodenal triglyceride infusion (10% intralipid at 1 mL min-1) was started during antral phase I activity and continued for 60 min. On one of the days GTN (600 micrograms) was given sublingually 20 min after start of the triglyceride infusion. The tonic pyloric motor response to triglyceride [5.6 (SEM 0.8,) vs. 2.7 (1.3) mmHg, P < 0.001] and both the number 3.2 (0.2) vs. 2.2 (0.2) min-1, P < 0.05] and amplitude [40 (4) vs. 27 (5) mmHg, P < 0.05] of phasic isolated pyloric pressure waves were reduced by GTN. These observations suggest that NO mechanisms are involved in the regulation of pyloric motor activity in humans.

Adolescent↗
PubMed1996

Insulin-associated modulation of neuroendocrine counterregulation, hypoglycemia perception, and cerebral function in insulin-dependent diabetes mellitus: evidence for an intrinsic effect of insulin on the central nervous system.

Evidence for an intrinsic effect of insulin on the central nervous system is accumulating. To test the hypothesis that insulin per se may modulate neuroendocrine counterregulation, hypoglycemia perception, and cerebral function in insulin-dependent diabetes mellitus, we examined 27 patients without any sign of classical autonomic neuropathy or evidence of so-called hypoglycemia unawareness. We used the hyperinsulinemic (0.67 vs. 2.00 mU/kg.min), stepped hypoglycemic (5.6/3.5/2.4/2.0 mmol/L) clamp technique to assess the patient's awareness of and response to equivalent hypoglycemic stimuli under different degrees of physiological hyperinsulinemia (approximately 270 vs. approximately 810 pmol/L) after an overnight euglycemic clamp (5.6 mmol/L). Simultaneously, the patient's cerebral function was assessed from his electrophysiological activity and neuropsychological skills. Higher degrees of physiological hyperinsulinemia caused enhanced neuroendocrine response (adrenaline, P < 0.05; noradrenaline, P < 0.03; GH, P < 0.02; beta-endorphin, P < 0.03; ACTH, P = 0.12; cortisol, P = 0.06; PRL, P = 0.08) and symptom awareness (total symptoms, P < 0.04; autonomic symptoms, P < 0.02; neuroglycopenia symptoms, P < 0.05; sweating, P < 0.05; heart pounding, P < 0.02; trembling, P < 0.01; lack of concentration, P < 0.02) to occur. Deteriorations of electrophysiological activity (middle latency auditory-evoked potentials, P < 0.04; Pa peak latencies, P < 0.05; Pa-V interpeak latencies, P = 0.08) and neuropsychological skills (Stroop test, P < 0.05; trail making, P = 0.12) were more pronounced the higher the insulin level, but at similar blood glucose concentrations. We conclude that insulin-associated modulation of neuroendocrine counterregulation, hypoglycemia perception, and cerebral function may occur in insulin-dependent diabetes mellitus, which indicates an intrinsic effect of insulin on the human brain.

Adult↗
PubMed1995

Improvement of impaired counterregulatory hormone response and symptom perception by short-term avoidance of hypoglycemia in IDDM.

OBJECTIVE: To test the hypothesis that impaired counterregulatory hormone response and symptom perception, induced by recurrent hypoglycemic episodes over 2 days, may be improved by short-term (2-day) avoidance of hypoglycemia. RESEARCH AND DESIGN: We examined two groups of insulin-dependent diabetes mellitus (IDDM) patients (n = 16), none of whom exhibited signs of peripheral or autonomic neuropathy. Two sequential euglycemic-hypoglycemic clamp studies were performed applying stable glycemic plateaus of 5.6, 3.3, 2.2, and 1.7 mmol/l, at which the patients' awareness of and responses to hypoglycemia were evaluated. In the intervention group (n = 11), three short-term hypoglycemic ( < 2.2 mmol/l) episodes (days 1-3) preceded the first clamp study (day 4), whereas the second clamp study (day 6) followed a 2-day interval of strict avoidance of hypoglycemia. A control group (n = 5) was introduced to detect adaptation effects caused by the study procedure per se. RESULTS: This short-term avoidance of hypoglycemia caused improvement of the impaired counterregulatory hormone response during insulin-induced hypoglycemia involving adrenaline (P < 0.05), adrenocorticotrophic hormone (P < 0.03), and cortisol (P < 0.05). Improvement of hypoglycemia symptom awareness encompassed overall symptom perception (multiple analysis of variance, P < 0.04) and the automatic symptoms of heart pounding (P < 0.05) and sweating (P < 0.05). CONCLUSIONS: The previously reported compromised neuroendocrine counterregulation and symptom awareness, occurring as a consequence of repetitive hypoglycemic episodes over 2 days, may be improved by a single 2-day interval of strict avoidance of hypoglycemia

Adult↗
PubMed1994

Recovery of hypoglycaemia-associated compromised cerebral function after a short interval of euglycaemia in insulin-dependent diabetic patients.

To test the hypothesis that compromised cerebral function, induced by recurrent hypoglycaemic episodes, may recover after a short interval of euglycaemia, we examined electrophysiological activity and symptom awareness during two sequential euglycaemic-hypoglycaemic clamp studies in 11 insulin-dependent diabetic patients without any signs of peripheral or autonomic neuropathy. Neurophysiological testing and evaluation of hypoglycaemic symptoms were performed at stable glycaemic plateaus of 5.6, 3.3, 2.2, and 1.7 mmol/l. The first clamp study was preceded by 3 short-term hypoglycaemic episodes, whereas the second clamp study followed a 2 day interval of strict euglycaemia. The latter caused a recovery of electrophysiological activity, which was demonstrated by recovery of delays of the middle latency auditory evoked potentials (latency shift of the P(a) component, MANOVA, P < 0.01). Reversal of hypoglycaemic symptom unawareness involved the overall symptom perception (MANOVA, P < 0.04), as well as the autonomic symptoms of heart pounding (P < 0.05) and sweating (P < 0.05). We conclude that the previously reported impaired cerebral function, occurring as a consequence of repetitive hypoglycaemic episodes, may recover after a single euglycaemic interval.

Acoustic Stimulation↗
PubMed1994

Young hospital doctors after night duty: their task-specific cognitive status and emotional condition.

Sleep deprivation is an unpleasant burden of young hospital doctors during their medical training. It may disrupt the balance between coping strategies available to them and the professional demands encountered. Impaired medical care offered by sleep-deprived juniors may be a consequence. Valid research work on this subject is rare and surprisingly contradictory. Therefore, we evaluated the task-specific cognitive status and emotional condition of 40 young hospital doctors (27 men and 13 women, 29.9 +/- 2.9 years of age) at the University of Tuebingen, all of whom were in the beginning of their academic career. Subjects were tested twice acting as their own control, once at 8.00 am after a night off duty (OD) (at least 6 hours of uninterrupted sleep), and once at a similar time after a night on call (OC) being in the hospital for 24 hours. Standardized and reliable psychometric tests thought to represent daily routine medical function were performed. On-call activities were recorded by means of a sleep diary, whereas a questionnaire interrogated aspects of private and professional life. Neuropsychological function deteriorated significantly: number connection test (per cent of norms +/- SD, 103.2 +/- 9.8 OC vs 107.8 +/- 10.5 OD, F = 27.7, P < 0.001), things-to-do list (correct items +/- SD, 6.7 +/- 1.2 OC vs 7.4 +/- 1.5 OD, F = 12.7, P < 0.01), Vienna reaction timer (per cent of norms +/- SD, 95.6 +/- 9.0 OC vs 97.7 +/- 10.4 OD, F = 4.8, P < 0.05), Stroop test (T-values +/- SD, 59.7 +/- 6.3 OC vs 64.6 +/- 7.1 OD, F = 37.1, P < 0.001), ECG test (correct responses +/- SD, 38.3 +/- 7.3 OC vs 43.4 +/- 6.5 OD, F = 45.2, P < 0.001) and status of mood (T-value +/- SD, 60.3 +/- 9.0 OC vs 54.0 +/- 6.6 OD, F = 19.6, P < 0.001). Cognitive function and mood status of young hospital doctors after a night on call decrease considerably. In view of the special vulnerability of medical trainees to occupational stress all efforts are warranted to reduce sleep deprivation in the medical profession.

Adaptation, Psychological↗
PubMed1994

Successful monochemotherapy of extensive gastrointestinal Kaposi's sarcoma with bowel obstruction in acquired immunodeficiency syndrome.

We report the case history of a 28-year-old homosexual man of Caucasian origin whose diagnosis of acquired immunodeficiency syndrome was established one year before admission on the basis of a positive human immunodeficiency virus serology and cutaneous Kaposi's sarcoma. Severe postprandial vomiting pointed to bowel obstruction in an emaciated, poor risk patient. Endoscopy revealed multifocal, violaceous tumours throughout the upper gastrointestinal tract which, eventually, obstructed the duodenum. Histology confirmed the putative diagnosis of gastrointestinal Kaposi's sarcoma, which responded well to monochemotherapy with vincristine. Significant clinical improvement and repeat endoscopy indicated tumour regression and resolution of bowel obstruction.

Adult↗
PubMed1993

Comparison of a mechanized version of the 'König' reaction and a fluorescence polarization immunoassay for the determination of nicotine metabolites in urine.

Smoking can be detected by the determination of cotinine in urine. We compared the performance of an automated modification of the 'König' reaction adapted to a centrifugal analyzer with an automated commercial fluorescence polarization immunoassay (TDX system). In the latter assay, cotinine, as the primary metabolite of nicotine, can be measured with high specificity. In contrast, the 'König' reaction also detects nicotine metabolites other than cotinine by a group colour reaction. Analysis speed of the 'König' reaction was about 66 samples/h with a detection limit 2 S.D. above the mean value of urine samples of non-smokers. Analysis speed of the TDX system was 41 samples/h. The coefficient of variation (C.V.) of both methods in smokers' urine was 8.6% ('König' reaction) vs. 3.4% (TDX system) in the high range and 16.4% vs. 9.5% in the low range. In a controlled, prospective study recruiting 86 cigarette-smoking volunteers, 83.7% were correctly classified as being smokers by both systems, 13.9% were classified as smokers by the 'König' reaction only and 2.4% were misclassified as non-smokers by both systems. Thus, the sensitivity of the 'König' reaction seems to be higher than in the TDX system (97.6% vs. 83.7%). Of 33 non-smoking individuals, 81.8% were correctly classified as non-smokers by both systems, 18.2 were misclassified as smokers by the 'König' reaction and no person was misclassified by the fluorescence polarization immunoassay. Thus, the specificity of the TDX system seems to be higher than that of the 'König' reaction (100% vs. 81.8%). We conclude that both systems are applicable to detect individuals who smoke regularly by simple urine testing. The higher specificity of the TDX system is outweighed by the higher sensitivity of the 'König' reaction at much lower cost.

Autoanalysis↗