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Biomedical subjects

M Heer

Publications and source records attributed to M Heer.

At least 19 recordsLinked to original sources
PubMed1992

Biliary obstruction: treatment with self-expanding metal prostheses.

The authors percutaneously and endoscopically inserted 58 Wallstent endoprostheses in 42 consecutive patients with benign and malignant obstructive biliary stenoses. The three patients with benign obstructive jaundice were followed up for 48 months. Two of the stents occluded due to sludge formation, prompting percutaneous reentry. The 39 patients with malignant disease were followed up for 18 months. Twenty-six of these patients died 3 days to 1.5 years (mean, 133 days) after the procedure. Thirteen are alive after 2-12 months (mean, 242 days). Recurrent jaundice occurred in 11 patients (28%): in four patients due to tumor growth over the proximal end of the stent, in one patient due to excessive gallbladder hydrops, and in six patients due to liver failure. Although autopsy investigations revealed the possibility of tumor growth onto the inner surface of the stent through the stainless steel mesh of the endoprosthesis, stent occlusion by tumor ingrowth into the lumen was not encountered.

Adult↗
PubMed1992

Effects of an acute saline infusion on fluid and electrolyte metabolism in humans.

Several hormonal systems participating in body fluid and electrolyte homeostasis were investigated in six healthy volunteers in a supine body position during a period of 9 days and nights. Under strictly controlled conditions, striking circadian rhythms were observed for plasma levels of vasopressin, renin, aldosterone, guanosine 3',5'-cyclic monophosphate, cortisol, and epinephrine. Nocturnal decreases and diurnal increases in urine flow rate and urinary excretion of electrolytes were observed and closely paralleled the urinary excretion of urodilatin. During 48 h after an acute isotonic saline infusion (2 liters within 25 min) and after a 48-h control experiment the urinary excretion of H2O and electrolytes, and simultaneously the alterations in endocrine systems participating in body fluid homeostasis, were determined. Urine flow and urinary electrolyte excretion rates were significantly increased during 2 days after the saline infusion. The largest increase in urinary fluid and electrolyte excretion was observed between 3 and 22 h postinfusion. These long-term changes were paralleled by altered H2O and Na balances and also by elevated body weights that returned to baseline values with an approximate half-life of 7 h. These data suggest that vasopressin, atrial natriuretic peptide, and catecholamines are unlikely to be of major importance for the renal response to this hypervolemic stimulus. The renin-aldosterone system was suppressed during 2 days postinfusion. This suppression correlated with the effects of saline load on Na excretion. However, the closest relation with Na excretion was observed for the kidney-derived member of the atrial natriuretic peptide family, urodilatin, which was considerably increased during the long-term period up to 22 h postinfusion. Thus these data show that the human body in supine position requires approximately 2 days to regulate the amount of Na and H2O provided by an acute saline infusion. The data also suggest that urodilatin and the renin-aldosterone system might participate in the long-term renal response to an acute saline infusion and also in the mediation of circadian urinary excretion rhythms.

Adult↗
PubMed1992

Diuresis and natriuresis following isotonic saline infusion in healthy young volunteers before, during, and after HDT.

In the present study the response to acute saline loading was investigated. During a 24-day study period six male subjects followed a standardized diet including a daily intake of 40 ml water and 125 mg NaCl per kg body weight. Before, during, and after a ten-day period of 6 degrees head down tilt (HDT) each volunteer received an intravenous 0.9% saline infusion of 22 ml/kg body weight over 20 minutes. HDT produced significant losses in body weight and in blood volume, but the responses to saline loading were similar during all phases of the study. Plasma levels of atrial natriuretic peptide (ANP) did not increase, while plasma levels of cyclic GMP increased by about 40% 90 minutes after each infusion. Urine flow nearly doubled during second hour post-infusion. Sodium excretion showed a 3-fold increase and remained elevated during the third hour, while potassium excretion was significantly reduced. Urinary excretion of cyclic GMP reached a peak during the second hour post-infusion. At the end of these short-term periods the cumulative water- and sodium-balance data disclosed that only about 20% of the infused water and less than 15% of the infused sodium was excreted during each experiment. In addition to the short-term renal response, urine flow and sodium excretion remained significantly elevated for more than 48 hours after each saline load. The long-term renal response was paralleled by an increased excretion of urinary cyclic GMP. HDT produced significant changes in body fluid distribution, but only minor changes in the regulatory responses to an acute saline load. We conclude from these data that the excretion of an acute isotonic saline load requires several days and that the renal response appears to be independent of the secretion of ANP from the heart.

Adult↗
PubMed1992

The effects of a 10-day period of head-down tilt on the cardiovascular responses to intravenous saline loading.

We tested the hypothesis that adaptation to microgravity, simulated by a 10-day period of head-down tilt (HDT), alters the responses to an intravenous fluid load by causing a larger fraction of the infused volume to be retained and magnifying the acute hemodynamic effects. HDT caused a significant (p less than 0.01) decrease in blood volume (-0.72 liters) and weight (-1.6 kg). Rapid infusion (22 ml/kg over 20 min.) of isotonic saline before, during, and after HDT produced a transient blood volume expansion with 18% of the infusate retained intravascularly after 2 hours. HDT had no effect on this response. Control hemodynamics were significantly different with lower cardiac output and higher total peripheral resistance (TPR) during and after HDT. Saline caused significant increases in cardiac output, heart rate, and stroke volume and a decrease in TPR. The magnitude and time course of these changes were not altered by HDT. The results refute the hypothesis and suggest that during HDT new set points or operating points were established for the control of intravascular volume and hemodynamic state.

Adult↗
PubMed1992

Effects of head-down tilt and saline loading on body weight, fluid, and electrolyte homeostasis in man.

We studied the effects of head-down tilt bedrest (HDT) on body weight, fluid and sodium homeostasis. A fluid load session with rapid intravenous infusion of 22 ml/kg body weight (BW) isotonic saline was performed before, during and after HDT. During the pre- and post HDT periods the test subjects were given a diet containing 2600 kcal/day. The energy intake was reduced to 2000 kcal/day during HDT. Water intake was kept constant at 40 ml/kg BW, sodium intake was 2.2 mmol/kg BW and protein intake was 1.4 g/kg BW, while the daily fat and carbohydrate intake was reduced during the HDT period. As expected plasma volume and BW changed rapidly in the beginning of HDT and during early recovery. A total body water loss of 0.6 l was observed within the second day after tilting. Plasma volume was reduced by 16% during HDT-bedrest. The time course of the body fluid loss paralleled a decrease in body sodium that then remained fairly constant during the HDT-bedrest period (except for the interference caused by the fluid loading on day S06). A restoration of body fluid and body sodium content occurred early in the recovery period. Fluid loading caused a negative fluid balance of 0.6-0.9 l over a 48 hr period following infusion regardless of the phase of the HDT study. These results demonstrate that under our strictly controlled conditions 1) HDT alters body fluid and sodium balances, 2) a standard fluid loading causes a net negative 3-day fluid balance during all phases of the study.

Adult↗
PubMed1991

[Acute fatal liver insufficiency due to valproic acid therapy].

Fatal hepatic failure associated with valproic acid therapy is a rare side effect occurring in 1:5000-10,000 of the patients exposed to this antiepileptic drug. Its relevance arises from its fatal outcome and the high number of patients who are treated with this drug (one million worldwide in 1988). 112 cases were published up to 1988. Most of the affected patients were young (less than 10 years old), male, and mentally retarded. Many were under antiepileptic polytherapy. The children of this age group constituted only 23% of the patients treated with valproic acid but 73% of all fatalities. 90% of the patients developed hepatic failure in the first 5 months of therapy. Low doses or therapeutic serum levels of valproic acid do not prevent this dramatic event. Specific therapy is not known. In addition to the case report we review the literature and make recommendations for monitoring therapy with valproic acid.

Adult↗
PubMed1991

Valproic-acid-induced pancreatitis. Case report and review of the literature.

We report a case of pancreatitis with fatal liver failure, in a 21-year-old, mentally retarded patient, taking valproic acid (VPA) therapy, together with a review of the literature of this rare side effect. Until March 1991, only 24 cases of isolated pancreatitis and six cases (including ours) of pancreatitis with hepatic failure under VPA treatment have been published. Most of the patients were less than 20 years old, and injury to the pancreas developed during the first year of therapy in 72% of the patients, approaching a mortality of 21%. Pancreatitis associated with liver failure has a poor prognosis mainly because of the VPA hepatotoxicity. It seems that the pancreatic side effects fluctuate between two extremes: asymptomatic hyperamylasemia and fatal pancreatitis.

Adult↗
PubMed1991

Classification of the free fluid reservoir in the calf by electrical impedance tomography.

The Electrical impedance tomography computes images of resistivity distribution which allow to analyse the body fluid content. The Sheffield system, Applied Potential Tomography (APT) was chosen to examine fluid shifts in the calf following body postural change, saline infusion (FL), and lower body negative pressure stress (LBNP). The APT allows the detection of differently reacting regions in the tomogram. The overall images of APT showed an exponential resistivity increase after the body position change from upright to 6 degrees head down tilt (HDT). During LBNP the pattern of the APT images looked the same as during FL. Both showed a resistivity decrease in the overall images. The outer surface showed a different magnitude of resistivities compared to the inner region in all experiments. A comparison of the overall APT images with the tomograms simultaneously obtained by NMR in one test subject showed the same tendency. This leads to the conclusion that the changes in the fluid reservoir of the calf may be classified by electrical impedance tomography.

Adult↗
PubMed1990

[Risk of malignancies in celiac disease--a retrospective study].

A review of 52 patients with celiac disease showed the development of malignant tumors in eight cases (15%). The following malignomas were diagnosed: one malignant lymphoma, one multiple myeloma, one rhabdomyosarcoma, one carcinoma of the uterus, one carcinoma of the sigmoid colon and three adenocarcinomas of the small bowel. Patients with tumors showed significantly lower hemoglobin, lower serum albumin, and higher sedimentation rates than patients without tumors. The possibility of underlying malignoma must always be considered in all patients with newly diagnosed coeliac disease and in patients where symptoms of a known celiac disease change without alteration of the prescribed diet.

Aged↗
PubMed1990

[Adenocarcinoma of the small intestine in celiac disease. Case report and literature review].

We describe three patients with celiac disease complicated by adenocarcinoma of the small intestine, and summarize the 36 cases of this association that have been reported. Retrospectively we found an increased risk (relative risk 25-250) of developing adenocarcinoma of the small intestine in patients with celiac disease in the region of Winterthur (north-east Switzerland). We therefore suggest that celiac disease be considered a premalignant condition not only for malignant lymphoma and gastrointestinal tumors, but also for adenocarcinoma of the small intestine. Synchronous or metachronous development of carcinoma in one of our patients and in two cases reported in the literature offer further evidence that celiac disease is a premalignant condition for adenocarcinoma of the small bowel. In several patients celiac disease was diagnosed only after diagnosis of the carcinoma. With regard to asymptomatic or subclinical celiac disease, it seems justifiable to search for possible underlying celiac disease in all patients with established diagnosis of adenocarcinoma of the small intestine.

Adenocarcinoma↗
PubMed1989

[Segmental hemorrhagic colitis following amoxicillin therapy].

We report on three young females complaining of bloody diarrhea of acute onset due to hemorrhagic colitis associated with oral amoxicillin therapy. The bloody diarrhea with abdominal cramps began 4 to 6 days after starting the treatment. Right colon was involved in two patients, and the descending and sigmoid colon in the other. Stool cultures and search for Cl. difficile toxins were repeatedly negative. Biopsy revealed marked mucosal hemorrhage (2/3), erosions (2/3) and thrombosed vessels (2/6). Symptoms rapidly resolved after 2 to 6 days. Extensive allergic evaluation in one patient did not reveal a hypersensitivity reaction. A literature review reveals another 31 patients with this characteristic form of colitis associated with ampicillin or amoxicillin therapy.

Adult↗
PubMed1988

[Colorectal carcinoma following radiotherapy of gynecological carcinoma].

To assess the risk of radiation-induced cancer of the colon we studied 196 patients with a history of radiation treatment for cancer of the female genital system. After a median follow-up of 12.4 years (range 10-15 years) corresponding to 1172 patient-years, 94 (48%) patients were still alive. 84 (89%) of these patients were evaluated for a second primary cancer to the colon. In 38 (45%) colonoscopic examination was performed. 3 patients were found to have a second primary cancer to the colon compared with 0.32 expected (relative risk 9.3) on the basis of rates from the Zürich Tumor Registry. Due to partial long-term survival, patient non-compliance and non-feasibility of colonoscopic examination, only one fourth of all patients initially treated by radiotherapy for cancers of the female genital system were suitable for colon screening. For these high risk women, colorectal tumor screening should be integrated into a gynecologic tumor follow-up.

Adult↗
PubMed1988

[Loss of vision as a complication of acute pancreatitis].

A report is presented on two patients with severe visual loss and scotoma following an episode of alcohol-induced pancreatitis. A 35-year-old man with pancreatitis developed visual loss in both eyes. Ophthalmoscopic examination revealed extensive ischemic infarcts with bilateral hemorrhage and cotton-wool spots, a clinical picture similar to that of (post-traumatic) Purtscher's retinopathy. Goldmann visual fields demonstrated paracentral scotomas. Fundoscopic lesions had disappeared 3 months after the acute event and visual acuity improved gradually from 0.1 to 1.0. In a 36-year-old man, cerebral infarction was established by CT as a possible cause of visual loss. CSF examination revealed Sudan-III positive material suggesting cerebral fat embolism as the cause of cerebral infarcts. Visual fields showed central scotomas. During the 4-year follow-up period there was a gradual improvement in visual acuity.

Acute Disease↗
PubMed1987

[Ischemic-granulomatous colitis: a new differential diagnosis from Crohn's colitis?].

In patients with inflammatory bowel disease the presence of epitheloid cell granuloma is considered to be the most reliable single criterion for the presence of Crohn's disease. We report on 6 patients (5 female, 1 male, mean age 73.5 years) with acute onset of inflammatory bowel disease, in whom the presence of epitheloid cell granuloma led to the diagnosis of Crohn's disease. However, concomitant major bleeding (4/6), absence of small intestinal involvement, and absence of extraintestinal manifestations suggested the presence of ischemic colitis. Histologic findings including thrombosed vessels (6/6), mucosal (5/6) and submucosal (3/4) hemorrhage, and mucosal (3/6) and submucosal (3/4) fibrosis supported this diagnosis. A review of the literature suggests that many clinical features of assumed Crohn's disease in elderly patients are atypical and would be most consistent with an ischemic pathogenesis: rarity of fistula, low recurrence rate, low rate of small intestinal involvement and extra-intestinal manifestations, and increased incidence of major colonic bleeding would best fit with an ischemic pathogenesis in at least some of these patients. We suggest that in elderly patients with "Crohn's colitis", even in the presence of epitheloid cell granuloma, an ischemic etiology should be considered.

Age Factors↗