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Biomedical subjects

R Stenling

Publications and source records attributed to R Stenling.

102 records · Page 6Linked to original sources
PubMed1985

DNA content in renal cell carcinoma with reference to tumor heterogeneity.

DNA content was successfully determined by flow cytometry in 196 tissue samples from 25 renal cell carcinomas. Twelve tumors (48%) were homogeneously diploid/near-diploid, whereas 11 tumors were aneuploid and 2 tumors were polyploid. Cell clones with different DNA content were found in 11 tumors demonstrating a considerable heterogeneity in the non-diploid tumors; 9 of these 11 heterogeneous tumors contained both aneuploid and diploid cell clones. Tumor samples morphologically classified as grade 1 and 2 were 98% diploid and grade 4 samples were 78% aneuploid. No correlation between DNA distribution and morphologic grade was found for grade 3 tumor samples. Tumor proliferation rate, as determined by the fraction of cells in S-phase, was significantly higher in aneuploid samples compared to normal kidney tissue samples and diploid tumor samples.

Adult↗
PubMed1984

Stereological studies on the rat small intestinal epithelium. III. Effects of short-term alloxan diabetes.

Short-term experimental diabetes was used to explore the effect of hyperplastic adaption of the small intestine mucosa on the structure of its absorptive cells. Diabetes was induced in adult female rats by intravenous alloxan administration under kidney protection; similar rats, injected with physiological saline, served as controls. Quantitative light microscopy, performed after 1 month of diabetes, revealed structural changes in the jejunal mucosa consistent with hyperplasia. These changes comprised increased height of the villi (31%) and increased depth of the crypts (34%) in comparison with the control rats. At the electron microscopical level, stereological measurements of the jejunal absorptive cells revealed a decrease in their apical surface area, both for the apical surface density (24%) and for the enlargement factor due to the microvilli (12%). In the duodenal mucosa, this kind of experimental diabetes did not induce any significant light microscopical or electron microscopical changes of the villi, the crypts, or the absorptive cells. It was concluded that the adaptive capacity of the structure of the small intestine mucosa to short term experimental diabetes is more pronounced in the jejunum than in the duodenum, and that the adaptive response also includes alterations in the structure of the absorptive cells.

Animals↗
PubMed1984

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↗
PubMed1984

Surface ultrastructure of the small intestine mucosa in children with celiac disease. I. Untreated disease and effects of long-term gluten elimination and challenge.

Forty-eight gut mucosa specimens from 27 children with celiac disease, diagnosed by means of conventional serial biopsies taken at different dietary conditions, were studied by means of scanning electron microscopy (SEM). The observations were correlated with those made by concomitant dissection microscope (DM), light microscope (LM), and transmission electron microscope (TEM) examinations. Five children with constitutional short stature served as controls. The results of the SEM analyses were in good conformity with the observations made by DM, LM, and TEM. In addition, SEM was found to offer further structural variables to be analyzed. In active celiac disease and after challenge with dietary gluten, which is necessary to establish the diagnosis of children, the lesions specifically observed by SEM were (1) a strikingly uniform destruction of the villi and a distortion of the enterocytes but with preserved extrusion zones, and (2) a decrease and disruption of the glycocalyx of the enterocytes with marked irregularity of the microvilli. After successful dietary treatment and despite a normalization of the gut mucosa by routine LM, SEM often disclosed persisting lesions of the enterocytes. It was concluded that by inclusion of SEM in the routine assessments of gut biopsy specimens in children with celiac disease, the diagnostic precision becomes increased.

Biopsy↗
PubMed1984

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↗
PubMed1983

Stereological studies on the rat small intestinal epithelium. II. Effects of antrectomy and antral exclusion.

Morphological studies were carried out on the absorptive cells of the small intestine to elucidate their reaction to shunt operations and to variations in endogenous gastrin production. Adult rats were subjected to 1) antrectomy with gastro-duodenostomy, 2) antrectomy with gastro-jejunostomy, 3) antral exclusion, or 4) sham operation. Quantitative light microscopy revealed no significant differences among the different groups with regard to the height of the absorptive cells and to the internal surface area of the duodenum or jejunum. In contrast, stereological measurements at electron-microscopical level demonstrated significant differences in the apical surface area of the absorptive cells. After antral exclusion or antrectomy with gastro-jejunostomy the apical surface area in the duodenal blind loop increased by 28% and 78%, respectively, in comparison to the sham-operated rats. A reduction of this area by approximately 30-40% was registered for the jejunal absorptive cells after antrectomy or antral exclusion. Hormone levels as well as intraluminal factors are presumably responsible for these variations in the brush-border surface area.

Animals↗
PubMed1983

Relationship between morphological findings and function of the small intestine in familial amyloidosis with polyneuropathy.

Twenty-seven patients with familial amyloidosis with polyneuropathy were studied with regard to the morphology of the small intestine, and this was correlated to symptoms and malabsorption features. The mucosa was normal in all cases investigated by the dissecting microscope, the light microscope, and the scanning electron microscope. Amyloid was demonstrated in 83% of the cases by the presence of green birefringent material in the biopsy specimens stained with alkaline Congo red and examined in polarized light. Nineteen patients had steatorrhea, and 12 had pathological D-xylose test results. The degree of amyloid infiltration did not correlate with these data, nor did the symptomatic state correlate with the amount of amyloid in the biopsy specimens. The surface ultrastructure was normal when investigated by means of the scanning electron microscope in all patients except five in whom the glycocalyx was altered. As a group, however, those five did not differ in any respect from the rest of the patients. Rod-shaped microorganisms were shown to adhere to the surface in one patient. The results suggest that mechanisms other than bowel-wall deposition of amyloid cause the dysfunction of the gastrointestinal tract in familial amyloid polyneuropathy.

Adult↗
PubMed1981

Stereological studies on the small intestinal epithelium of the rat. 1. The absorptive cells of the normal duodenum and jejunum.

Quantitative macroscopic, light-microscopic and electron-microscopic studies were performed on the small intestine of fasted and non-fasted adult, male Sprague-Dawley rats. In non-fasted rats the small intestine was longer than in fasted rats. Due to the presence of villi the surface area in the duodenum and the jejunum was enlarged about six times. The microvilli on the villous crests caused a surface enlargement by 13 times in the duodenum (value corrected for overestimation due to section thickness), and 19 times in the jejunum of the fasted rats. At the base of the villi these values were about 50% lower. It was calculated that, in the fasted rats, the total enlargement of the luminal surface area--due to villi and microvilli--was 63 times in the duodenum and 81 times in the jejunum (corrected for section thickness). Differences between the villous crest epithelium and the villous base epithelium were also found with regard to the mean cell height, and the volume densities of the absorptive cell nuclei, the mitochondria, and the paracellular channels.

Animals↗
PubMed1978

Congenital dyserythropoietic anaemia type III: an electron microscopic study.

The morphological features of erythroblasts in congenital dyserthropoietic anaemia (CDA) type III were studied by electron microscopy. Typical findings included clefts and blebs within the nuclear region, autolytic areas within cytoplasm, iron-filled mitochondria and myelin figures. The findings resembled those reported in other dyserythropoietic anaemias particularly in CDA type I; the main morphologic features which distinguished the two types were lack of spongy appearance of the chromatin, lack of cytoplasmic organelles within the nuclear region and intact nuclear envelope in CDA type III.

Adolescent↗
PubMedDate not supplied

Limited value of preoperative serum analyses of matrix metalloproteinases (MMP-2, MMP-9) and tissue inhibitors of matrix metalloproteinases (TIMP-1, TIMP-2) in colorectal cancer.

PURPOSE: We studied whether preoperative serum levels of free MMP-2, the MMP-2/TIMP-2 complex, and total amounts of MMP-9, TIMP-1 and TIMP-2 correlated to the tumor stage and prognosis in colorectal cancer. METHODS: Samples from 158 patients operated on for colorectal cancer (100 colon, 58 rectum) and samples from 80 healthy blood donors were analyzed using an ELISA technique. One hundred and thirty-three patients were resected for cure, (31, 61, and 41 in Dukes' stages A, B, and C, respectively). At follow-up in January 1998, 44 patients had died from their cancer after a median time 14 months (range 2-55). Fifteen patients died without tumor relapse. Ninety-nine patients were alive after, a median time of 46 months (range 17-68). RESULTS: Wide, overlapping ranges were observed for all factors both in the patients and in the control group. The patients as compared to the control group had significantly higher levels of free MMP-2 and total amounts of MMP-9, TIMP-1 and TIMP-2, whereas the level of the MMP-2/TIMP-2 complex was significantly lower. TIMP-1 was significantly higher in Dukes' D compared to Dukes' A-C cases; the other factors did not correlate to tumor stage. Elevated TIMP-2 levels (median cut-off limit), only, correlated to worse prognosis when analysed in all patients (p < 0.05). None of the factors (median cut-off limit) correlated to survival in Dukes' A-C patients; analyses based on the upper quartile cut-off limit demonstrated that elevated MMP-2 levels correlated to shorter survival time (p < 0.05). CONCLUSION: Serum analyses of free MMP-2 the MMP-2/TIMP-2 complex and total amounts of MMP-9, TIMP-1 and TIMP-2 are of limited value for tumor staging and prognosis in colorectal cancer.

Adult↗