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Biomedical subjects

H Nyhlin

Publications and source records attributed to H Nyhlin.

31 records · Page 2Linked to original sources

Surface ultrastructure of the small intestine mucosa in healthy children and adults: a scanning electron microscopic study with some methodological aspects.

Biopsy specimens of light microscopically (LM) normal small intestine mucosa from eight healthy, constitutionally short-statured children without signs of gastrointestinal disease and six healthy adults were studied by scanning electron microscopy (SEM) supplemented by transmission electron microscopy (TEM). The effects on surface morphology of various preparative procedures were also investigated, using small intestine mucosa from cats and rats. Fixation with OsO4--either alone, or following glutaraldehyde fixation--markedly changed the surface ultrastructure compared to that after glutaraldehyde fixation only. By low power SEM, some differences were observed in the appearance of the small gut mucosa between adults and young children. In adults and in children above 3 years of age, the villi were usually shaped like fingers or leaves, but in infants, ridge-shaped villi predominated. The villi showed, however, a smooth surface in both infants and adults, and medium and high power SEM displayed similar pictures, irrespective of age; here the typical structural features of the normal small gut mucosa in humans were (1) distinct extrusion zones at the crests of the villi and almost no signs of enterocyte extrusion along the sides of the villi, and (2) regular enterocytes with polygonal, flat, apical surfaces covered by a thick glycocalyx that obscured the underlying microvilli.

Adolescent↗

Clinical application of a selenium (75Se)-labelled bile acid for the investigation of terminal ileal function.

With the introduction of a selenium bile acid SeHCAT (tauro-23-75Se-Selena-25 homocholic acid) a new and clinically valuable test for the functioning of the terminal ileum has been made available. Previous studies have shown that the test detects patients with bile acid malabsorption due to ileal disease. In this study SeHCAT retention was evaluated in nine patients with Crohn's disease and in seven healthy controls after intravenous administration of 0.15 MBq (4 muCi). A simple way of expressing the results is proposed. By using the calculated time required to eliminate 50% of the SeHCAT (WBR50), information is obtained as to the degree of terminal ileum malfunction regarding bile acid absorption. Accurate values seem to be achieved within 48 hours. As the SeHCAT is a gamma-ray emitter the dose retained could be measured by external counting. We suggest a practical design for the test using a simple scintillation spectro-photometer with a single detector in a low-background room. In patients and healthy controls the SeHCAT retention as calculated by WBR50 was 63 hrs (15-163) and 120 hrs (range 99-141), respectively. There was no overall relation between SeHCAT elimination and the intestinal transit time, although in the patient group a significant correlation was demonstrated, probably secondary to the impairment of the terminal ileum. A significant correlation was shown between the outcome of the test and the faecal excretion of total bile acids.

Adult↗

The small-intestinal mucosa in patients with Crohn's disease assessed by scanning electron and light microscopy.

Small-intestinal mucosal biopsy specimens obtained by a Watson capsule were assessed by light (LM) and scanning electron (SEM) microscopy in 18 patients with various sites of Crohn's disease and in 6 healthy controls. By means of LM, partial villous atrophy of the upper small-intestinal mucosa was assessed in six patients. With the use of SEM a further seven patients were shown to have mucosal abnormalities of possible clinical significance. These specimens showed a convoluted villous pattern at low-power SEM and some also enterocyte irregularity, bulging, and surface ultrastructural distortion at medium- and high-power SEM. The medium- and high-power mucosal alterations were unevenly distributed. The high prevalence of abnormalities of the upper small-intestinal mucosa in patients with Crohn's disease elsewhere in the gastrointestinal tract adds further weight to the concept of a diffuse involvement along the entire gastrointestinal tract in Crohn's disease.

Adolescent↗

Evaluation of ileal function using 23-selena-25-homotaurocholate, a-gamma-labeled conjugated bile acid. Initial clinical assessment.

23-Selena-25-homotaurocholate is a synthetic bile acid labeled with a gamma-ray-emitting radioisotope 75Se. It is readily measured using external detectors and is thus suitable for whole-body counting. Whole-body retention was measured at 0, 4, and 7 days after oral administration to normal controls and to patients with disease of the small intestine, colon, or ileocecal region. Whole-body retention of less than 25% of the administered radioactivity within 4 days is definitely abnormal, but there was overlap between normal and abnormal groups at this time. At 7 days, whole-body retention less than 12% is abnormal and greater than 19% is normal. Between these limits, values may represent minimal ileal dysfunction not demonstrable by older techniques. Excretion of 23-selena-25-homotaurocholate follows a biexponential curve. The faster component has a half-life similar to that of natural bile acid. It is uncertain whether the slower component represents a hitherto unrecognized slowly turning over pool of bile acid or is a metabolic product of 23-selena-25-homotaurocholate not yet identified in vitro. There is a significant relationship between the whole-body retention of 23-selena-25-homotaurocholate and total fecal and primary bile acids. 23-selena-25-homotaurocholate is simple and acceptable for investigating ileal function.

Adolescent↗

Crohn's disease and the enterohepatic circulation.

Crohn's disease is a chronic inflammatory process which may affect any part of the alimentary tract. This cause is unknown. Overall the distribution of the lesions coincides with that of the enterohepatic circulation. A possible causative agent is a metabolic or ingested substance excreted into the bile in the form of a polar and inactive conjugates. The agent would have to have a prolonged half life in the enterohepatic circulation. In the ileocaecal region and elsewhere when bacterial colonisation occurs the inactive conjugates may be hydrolysed to release the active substance. This would act locally on the intestinal tissues either as a result of altering the physicochemistry of mucus or during passage through the gut wall.

Cecum↗

The relationship between active peptic ulcer, endoscopic duodenitis and symptomatic state after treatment with cimetidine.

Fifty patients with active peptic ulcers on endoscopy were randomly allocated for treatment with placebo or cimetidine (1.0 g daily) over a period of four weeks. All patients had free access to antacids to relieve epigastric pain. In the cimetidine group a significantly higher proportion of the ulcers had healed (82.6% of the patients) compared with the placebo group (48.0%). There was poor correlation between the healing of the ulcer and dyspeptic symptoms in the placebo group. The results suggest that the presence of endoscopic duodenitis is to a great extent responsible for the dyspepsia. Cimetidine treatment, besides healing the ulcers, also improved the endoscopic duodenitis and the symptomatic state more than placebo treatment. No significant clinical side effects were observed. Chemical abnormalities were only noted with respect to serum creatinine. In the cimetidine group there was a statistically significant rise in serum creatinine, which was most apparent after two weeks of treatment. However, the increase was slight and not significant among the males, whereas in the case of the females there was a large and highly significant rise. The reason for this sex difference is at present unknown.

Adolescent↗

Effect of long term treatment with hydrophilic colloid on serum lipids.

Thirteen patients with essential hyperlipoproteinaemia were treated over periods of 2--29 months with hydrophilic colloid made from Psyllium. Reduction of the increased serum cholesterol levels averaged 16.9 per cent, and the corresponding figure for the increased triglyceride levels was 52.0 per cent. The reduction of cholesterol and triglyceride was statistically significant (p less than 0.0025 and p less than 0.0005 respectively). No significant change in normal blood lipid levels was observed on administration of the Psyllium colloid.

Adult↗

In vivo measurements of lead in bone in long-term exposed lead smelter workers.

In-vivo measurements of lead concentrations in calcaneus (mainly trabecular bone) and tibia (mainly cortical bone) were performed by x-ray fluorescence (XRF) in 70 active and 30 retired lead smelter workers who had long-term exposure to lead. Comparison was made with 31 active and 10 retired truck assembly workers who had no known occupational exposure to lead. After physical examination, all participants provided blood and urine samples and answered a computerized questionnaire. Since 1950, blood lead has been determined repeatedly in lead workers at the smelter, which made it possible to calculate a time-integrated blood lead index for each worker. Lead concentrations in blood, urine, calcaneus, and tibia in active and retired lead workers were significantly higher than in the corresponding control groups (p < .001). The highest bone lead concentrations were found among retired lead workers (p < .001), which was the result of considerably higher lead exposure during 1940 to 1960. Lead concentrations in calcaneus in active lead workers were significantly higher than in tibia when expressed in ug of lead per gram of bone mineral, which suggests a quicker absorption over time in this mainly trabecular bone. The estimated biological half-times were 16 y in calcaneus (95% confidence interval [95% CI] = 11-29 y) and 27 y in tibia (95% CI = 16-98 y). A strong positive correlation was found between lead concentrations in calcaneus and tibia for all lead workers (r = 0.54; p < .001). A strong positive correlation was also found between the bone lead concentrations and the cumulative blood lead index. Blood lead, at the time of study, correlated well with bone lead concentrations in retired--but not in active--workers, reflecting the importance of the endogenous (skeletal) lead exposure. The findings in this study indicate that bone lead measurements by XRF can give a good index of long-term lead exposure. Tibia measurements offer a higher precision than calcaneus measurements. The method is of particular interest in epidemiologic studies of adverse health effects caused by long-term lead exposure.

Adult↗

Muscle magnesium and capillary basement membrane thickness in diabetes mellitus.

To evaluate a possible relationship between Mg deficiency and the development of microvascular disease in diabetes mellitus, quadriceps muscle biopsies for estimating Mg content and capillary basement membrane thickness, were studied in 16 patients with type I diabetes. The diabetic individuals had a slightly but significantly reduced muscle Mg content as compared with 13 healthy controls. There was a significant, positive correlation between capillary basement membrane width and age in the diabetic group, but no relationship between membrane thickness and muscle or serum concentration of Mg. However, diabetic patients with retinopathy (n = 6) showed a nonsignificant inverse correlation between basement membrane thickness and Mg parameters. The opposite tendency was found in patients without retinal lesions.

Adult↗