A multivariate morphometric analysis of the glomeruli in the normal and pathologically changed human kidney

Glomerular changes and alterations of zonula occludens-1 in the kidneys of Plasmodium falciparum malaria patients

Background

The process of cytoadhesion in Plasmodium falciparum malaria infection causes signaling processes that lead to structural and functional changes at the cellular level. Histopathological changes of acute kidney injury (AKI) in P. falciparum malaria often involve glomerular proliferation, thickening of the glomerular basement membrane, acute tubular necrosis, and interstitial inflammation. Focusing on the glomeruli, this study aimed to investigate glomerular and tight junction-associated protein- zonula occludens-1 (ZO-1) changes in P. falciparum malaria patients.

Methods

Kidney tissues were grouped into P. falciparum with AKI (Cr ≥ 265 μmol/L or 3 mg/dl), P. falciparum without AKI (Cr < 265 μmol/L), and normal kidney tissues (control group). Glomerular cells and the glomerular area were quantified and compared in three experimental groups. The tight junction was investigated immunohistochemically using tight junction-associated protein, ZO-1, protein marker. A further immunofluorescence study was performed in an endothelial cell (EC)-parasitized red blood cell (PRBC) co-culture system, to evaluate the tight junction protein.

Results

Glomerular cell proliferation was significant in P. falciparum with AKI (Cr ≥ 265 μmol/L). By contrast, the glomerular area decreased significantly. ZO-1 expression was significantly decreased in the AKI group compared with normal kidneys, and in kidney tissues without AKI (p < 0.05). This was further confirmed by the depletion in ZO-1 localization in ECs co-cultured with PRBCs.

Conclusions

In P. falciparum malaria with AKI, the decrease in glomerular area, despite glomerular cell proliferation, could be due to the collapse of cellular structures secondary to damaged tight junction-associated protein, ZO-1.

Development of the proximal tubule of the fetal rat kidney: morphometry and ultrastructural findings

The development of the kidney in fetal rats was investigated morphometrically and ultrastructurally. Both the length and volume of the proximal tubule increased with age. The total volume of functional glomeruli increased markedly from fetal day 20 onward. The ratio of total glomerular volume to total proximal tubular volume decreased with age and was less than 1 from fetal day 20 onward. The cells of the proximal tubule had numerous microvilli on their free surfaces and vacuoles in the apical region of the cytoplasm after fetal day 20. These findings indicate that the relative growth of the proximal tubule has exceeded that of the glomeruli by fetal day 20, and that increased filtration induces both the growth and the differentiation of the proximal tubule during development of the fetal rat kidney.

In search for the best qualitative microscopical or morphometrical predictor of oestrogen receptor in breast cancer

The correlation between oestrogen receptor (OR), qualitative and quantitative microscopical features has been studied in 198 breast cancers, 60 patients were younger than 50 years of age, 138 were older than 50. This age distinction was made because of the obvious age dependency of the OR-content, with 50 years as the cut-off point. Compared with elastosis grade, the morphometric features have a much lower percentage of doubtful cases (22.2 vs. 40.4%) with a higher percentage overall correct classifications (55.6 vs. 45.4%). In terms of sensitivity and specificity, selection of the best single predictor depends on the age of the patient. Mean nuclear area has the highest combination of sensitivity and specificity (88.9 and 80.0%) in woman younger than 51, while elastosis grade is the best single predictor in patients older than 50 (sensitivity: 91.2%; specificity: 70.6%). Using multivariate analysis, a combination of mean and standard deviation of the nuclear area results in 83.3% correct classifications with only 5% doubtfuls in the younger age group. With more features in the analysis, no false negatives and only 13.3% false positives is the most optimal result. In the older age group, a decision tree consisting of elastosis grade and mean nuclear area gives the best results. Subsequent investigation of mean nuclear area in elastosis grade 0 cancers gives a considerable reduction of the false negatives, thus increasing the specificity to 94.6% and the correct negative predictions to 72.7%. It is concluded that selective morphometry gives a considerable enhancement of the histopathological prediction capacities of oestrogen receptor in breast cancer.