Ossifying fibromyxoid tumour of soft parts: report of four cases including one mediastinal and one infantile.

Four cases of ossifying fibromyxoid tumour of soft parts are described. One of them was in the mediastinum, a hitherto unreported location of this rare neoplasm. Another was removed from the subcutaneous tissue of the head of a two-year-old girl, the youngest patient so far described. A peculiar feature of this tumour was haphazard spindle cell groups showing smooth muscle differentiation. One tumour was remarkably proliferative with 20 mitotic figures per 10 high power fields and 50% of cells positive for Ki-67 antigen. Immunohistochemical analysis revealed that all the tumours were diffusely positive for vimentin, and focally for S-100-protein. In addition to this the infantile tumour expressed focal alpha-smooth muscle actin, desmin and glial fibrillary acidic protein, while the mediastinal tumour expressed only alpha-smooth muscle actin and the highly proliferative one expressed none of these antigens. Background cells, including histiocytes, lymphocytes and mast cells were numerous. DNA cytometry analysis using both static and flow methods showed that the mediastinal tumour contained two cell clones, while the others were diploid. The proliferative fraction of cells (S plus G2 phases) was prominent in the proliferative and infantile tumours.

Characteristics of poly(L-)lactic acid suture applied to fascial closure in rats.

A new poly(L-)lactic acid (PLLA) thread was tested by applying it in fascial closures of male Wistar rats. The tissue reactions around the thread and in the fascial union, and the changes on the surface and the mechanical properties of the thread were evaluated at 1, 3, 6, 12, 28, and 52 weeks following surgery. Histologically, the extension of the general inflammatory reaction and the number of the different cell types did not markedly change during the 52-week follow-up period. The surface of the thread was intact up to 28 weeks when examined with the scanning electron microscope. At 52 weeks no thread was found. The breaking force and the stretching of the incubated PLLA thread was reduced about 20% during the first 2 weeks and it remained constant up to 6 weeks. The in vivo testing of the fascial strips closed with the PLLA thread retained their resistance against the breaking force, nearly comparable to that of the intact control fascial strips. It can be concluded that the PLLA thread is a suitable suture for wounds that require healing time of up to 28 weeks and thus need good support from the suture.

Studies on the role of lipid peroxidation in the acute toxicity of TCDD in rats.

Lipid peroxidation has been shown to be enhanced following exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), but its role in TCDD toxicity is unclear. The present study was undertaken to further elucidate the relations between lipid peroxidation and TCDD lethality. A time course and dose-response experiment in Long-Evans (L-E; LD50 ca. 10 micrograms/kg) and Han/Wistar (H/W; LD50 greater than 3000 micrograms/kg) rats showed that hepatic lipid peroxidation, measured as the amount of thiobarbituric acid-reactive substances (TBA-RS), was induced by TCDD dose-dependently in L-E, but not in H/W rats. Hepatic glutathione peroxidase activity was suppressed in much the same manner in both strains. Lipid peroxidation correlated with body weight loss in L-E rats alone. When 500 micrograms/kg of TCDD was given to L-E rats, lipid peroxidation increased about 3-fold on Day 11 in the liver, while no change was seen in cardiac or renal TBA-RS. The pair-fed controls did not survive the 11-day test period and exhibited gastrointestinal hemorrhages. At 6 days, liver atrophy and elevated (over 2-fold) TBA-RS values were recorded in pair-fed controls but not in their TCDD-treated counterparts. TCDD decreased hepatic glutathione peroxidase activity by almost 50% at 6 days, while pair-feeding was without effect. Liver morphology was different between TCDD-treated and pair-fed rats. Moreover, the livers of TCDD-treated L-E rats contained much higher concentrations of probably peripheral fat-derived fatty acids than did the livers of pair-fed or ad libitum control rats. Restricted feeding over 6 days induced hepatic lipid peroxidation more in H/W than in L-E rats. Endotoxin increased liver TBA levels similarly in both strains having an additive effect with high doses of TCDD in H/W rats. Added as a 0.5% concentration in chow, butylated hydroxyanisole (BHA), but not ethoxyquin, tended to increase survival rate and time in L-E rats exposed to 20 micrograms/kg of TCDD; at 50 micrograms/kg the only survivor was again in the BHA group. However, neither antioxidant had any effect on initial body weight loss. It is concluded that lipid peroxidation mainly arises as a secondary phenomenon in TCDD toxicity, is not the cause of the typical histopathological liver lesion, but may contribute to lethality.

Potential of nuclear morphometry and volume-corrected mitotic index in grading transitional cell carcinoma of the urinary bladder.

The potential of nuclear morphometry and volume-corrected mitotic index (M/V index) in grading cases of transitional cell carcinoma of the urinary bladder was studied. 30 cases of bladder cancer including all three WHO grades were evaluated. Four investigators selected independently the most atypical field from paraffin sections, and one investigator measured the nuclear areas from these fields using the IBAS 1&2 image analyzer system. Following the same sampling rule, four investigators counted the mitotic figures per area of neoplastic tissue in the microscopic image at an objective magnification of X40. The mean nuclear areas covered values from 28.1 to 139.0 microns 2 (mean +/- SD 57.2 +/- 18.9). The total variance of measurements was 359.1 and the mean variance between corresponding fields 110.2 (about 30% of the total variation). The efficiency was evaluated by estimating the fraction of falsely classified cases. Instrumental morphometry of nuclear area in a three-grade system gave an efficiency of 79% and of 90%, in a two-grade system. The M/V index varied from 0 to 54 (mean +/- SD 12.3 +/- 10.9). The total variance was 119.8 and the methodological variance 15.5 (about 13% of total variance). In a three-grade system this would correspond to an efficiency of about 75%; in a two-grade system the efficiency would be 88%. The results suggest that nuclear area and M/V index estimates constitute efficient grading systems in bladder carcinoma.

Target tissue morphology and serum biochemistry following 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure in a TCDD-susceptible and a TCDD-resistant rat strain.

The mode of action of the highly toxic environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is unknown. It was recently discovered that two strains of rat, Long-Evans (L-E) and Han/Wistar (H/W), differ widely in susceptibility to TCDD. Employing this strain divergence as a probe, the present study set out to assess the role of various biochemical and morphological effects in TCDD lethality. In the main experiment, the rats were treated once ip with 0,5,50, or (H/W) 500 micrograms/kg TCDD and killed 1 to 16 days postexposure. Several target organs were evaluated by light microscopy and a number of serum lipid and carbohydrate parameters as well as a few major regulatory hormones were analyzed. The results demonstrated that most alterations caused by TCDD were essentially similar in both strains. TCDD reduced circulating thyroxine to a slightly greater extent and more permanently in the sensitive L-E strain. Moreover, a highly significant interaction on thyroid-stimulating hormone was found among strain, dose, and time. Serum concentrations of corticosterone and free fatty acids were increased only in the L-E rats given 50 micrograms/kg TCDD, i.e., at an apparent LD100 dose level for this strain. Yet, the most striking interstrain difference was seen in the liver which was distinctly affected after Day 4 in L-E rats given 50 micrograms/kg TCDD but only marginally affected in rats from any H/W group. The lesion, while showing no necrotic cell changes, was suggestive of plasma membrane damage, possibly reflecting the production of free radicals. The relation of the findings to possible mechanisms of TCDD action is discussed.

Melanosis coli. Prevalence, distribution, and histologic features in 200 consecutive autopsies at Kuopio University Central Hospital.

The occurrence of large-bowel melanosis was evaluated by microscopy in 200 large bowels at autopsy. Melanin was seen as yellow-brown pigment in the macrophages of the lamina propria. The pigment stained with diastase-alcian blue PAS, Fontana, and iron stains. One hundred nineteen of 200 (59.5 percent) bowels showed melanosis, which was equally common in both sexes. Usually more than one segment was involved (most commonly, four segments). Melanosis was common in the proximal part of the colon, but much rarer in distal parts (sigmoid and rectum). Affected segments were successive; negative segments between positive ones were exceptional. If the rectum was affected, all five proximal segments were affected in 11 of 12 cases. The intensity of melanosis was directly related to the number of segments involved. In the oral part of the colon, affected males had a higher intensity of melanosis than affected women, but about the same intensity in the sigmoid and rectum. The fraction of patients with melanosis increased with age. Of men and women in the age group of 20 to 54 years, 32 and 44 percent were affected, and above the age of 75 years, 76 and 67 percent, respectively.

Toxicity of richterite in hemolysis test and macrophage cultures.

Richterite is a fibrous mineral associated with apatite deposits in eastern Finland. Fibre size features suggest potential toxicity but no data is available of fibrogenic effects on human lungs. The toxicity of richterite in a hemolysis test and in lung macrophage cultures was studied. In the hemolysis test richterite-rich samples showed the same degree of hemolysis as titanium dioxide whereas anthophyllite, crocidolite, chrysotile, wollastonite and quartz samples had distinctly higher degree of hemolysis. In the macrophage toxicity assay the percentage of dead cells was counted, and LDH, ASAT and acid phosphatase were determined from the culture medium. In this assay richterite showed lower toxicity than anthophyllite, crocidolite, chrysotile or quartz but gave higher values than titanium dioxide. Wollastonite showed similar level of toxicity. Differences were statistically highly significant. The results suggest that richterite (with wollastonite) belongs to a group of fibrous minerals which have distinctly smaller biological effect than traditional asbestos minerals.

Quantitation of staining for amyloid in histological sections: sources of variation, correlation analysis, and interstain reproducibility.

Five pathologists estimated with point counting the amount of amyloid in heart muscle autopsy samples from 19 patients who suffered from amyloidosis. The serial sections had been stained with 5 different methods. The different variation sources involved in a quantitative study on amyloid and the interstain reproducibility between the results given by these 5 stains were analyzed. The volume fractions of amyloid after different stains were subjected to correlation analysis. In our test system about a third (34%) of the variation was due to the point counting method. Sirius red had the lowest and Congo red the highest variation due to point counting, since Sirius red gave the most intense staining and highest volume fractions for amyloid. The volume fractions were lowest in Congo red. About 40% of the total variation was composed of the field variation. This variation includes the variation due to variation between fields, field selection and subjective intraobserver variation. Sirius red showed the smallest field variation in respect to the total variation. Congo red, on the other hand, had the highest variation. The variation caused by pure interobserver variation is presented by the difference between total variation and the calculated field variation. This was largest with Sirius red and smallest with Congo red. The pure interobserver variation accounted for about 26% of the total variation. The high reproducibility with Sirius stain is most probably due to the high volume fractions of positively stained material after this stain, not to low interobserver variation. Congo red seems to have low interobserver variation. The senior pathologists were more reliable in measuring the amyloid deposits than the junior pathologists as suggested by interstain reproducibility and variation.(ABSTRACT TRUNCATED AT 250 WORDS)

Reproducibility of morphometric measurements of amyloid after various staining methods.

Four histologic staining methods used for detecting amyloid (Congo red, viewed in both normal and polarized light, Sirius red, Crystal violet and Thioflavine T) were applied to heart muscle autopsy samples from 19 patients who suffered from amyloidosis. The amount of amyloid present was evaluated with morphometry (point counting) by five pathologists, and the interobserver reproducibility and variation of point counting in these staining methods were analyzed. The Sirius red method showed the least variation and was the most suitable stain for demonstrating amyloid with respect to reproducibility. Thioflavine T showed the greatest variation and was the least suitable stain with respect to reproducibility. The range of variation was considerable in all staining methods. The results show that stains differ in their specificity and sensitivity in staining amyloid, observers differ in their interpretation of staining results and certain stains result in more uniform interpretations than do others.

Reproducibility and variation of morphometric analysis of carcinoembryonic antigen staining in histopathology. The influence of standardized microscopic fields.

Using morphometric methods, five pathologists analyzed the positive staining for carcinoembryonic antigen (CEA) in sections from 17 ovarian tumors, with the intraclass correlation coefficient (ICC) and the mean values of the coefficients of variation (CV) used to assess reproducibility and variation. First, field and point scores for epithelium and mucin were estimated using 25 randomly selected square fields in sections from each of the tumors. The ICC range in the whole sample field was 0.53 to 0.81 (slight to substantial reproducibility) while the mean values of CV were 0.50 to 0.75. Second, the results of using random and standardized individual fields for the measurements were studied in three tumors. In random fields, the ICC was 0.57 to 0.71 (slight to moderate reproducibility) and the mean values of CV were 0.53 to 0.65. The corresponding values in standardized fields were 0.71 to 0.73 (moderate reproducibility) and 0.41 to 0.57, respectively. The results show that the variation is smaller and the degree of reproducibility higher in standardized fields. Considerable variation remains, however, revealing human factors as an important source of variation in practical morphometry.