The binding of peroxidase-labelled lectins to human breast epithelium. II--The reactivity of breast carcinomas to wheat germ agglutinin

The binding of peroxidase-labelled wheat germ agglutinin (WGA) to a series of 125 human breast carcinomas has been studied. Routine fixation and processing has been shown to have no deleterious effect on reactivity. In contrast to the homogeneous binding of WGA to normal and hyperplastic human breast previously reported, the binding of WGA to breast carcinomas exhibits heterogeneity. This is of two forms: (1) in relation to cell reactivity, which is significantly correlated to tumour differentiation, with fewer cells reacting in those carcinomas showing loss of histological differentiation; (2) with regard to the interaction between WGA and specific saccharides of cellular glycan-components, binding to sialic acid appearing to be of significance to varying degrees in some carcinomas but not in others nor, as previously reported, in normal breast. The alteration in WGA-saccharide interaction is an indicator of the heterogeneity of the carbohydrate chains of glycoproteins within neoplastic cells of the same tumour and between carcinomas. The other finding of note has been that of the significant association between heterogeneity of cellular reactivity to WGA and the presence of axillary lymph node metastasis, but a lack of correlation between virtual absence of reactivity and nodal metastasis.     

Regional expression of 5-HT1B receptor mRNA in the human brain

The regional mRNA expression pattern of 5-HT(1B) receptors has been extensively characterized in the rodent and guinea pig brain, but a detailed mapping of the 5-HT(1B) receptor mRNA expression in the human brain has not previously been performed. In the present study, the mRNA expression of 5-HT(1B) receptors was analyzed using in situ hybridization histochemistry and whole hemisphere sections of the human postmortem brain. The mRNA expression was compared with the autoradiographic distribution of 5-HT(1B) receptors. High levels of mRNA expression were found in the striatum, cortex, lateral geniculate nucleus, and raphe nuclei. The expression was higher in ventral than in dorsal striatal regions and was absent from the substantia nigra and pallidum, where high levels of 5-HT(1B) receptors were found. A layer-specific expression pattern was observed in cortical regions. The results extend previous knowledge about the localization of the 5-HT(1B) receptor in the human brain. This study provides evidence of a mismatch of the regional expression of 5-HT(1B) receptor mRNA and the 5-HT(1B) receptor distribution in human brain, similar to what has been demonstrated in other species. This is in line with the localization of this receptor subtype in nerve terminals. The results give support to species differences in the cortical mRNA expression pattern of this receptor subtype.     

Ophthalmoplegia due to mitochondrial DNA disease: the need for genetic diagnosis

We describe a patient with chronic progressive external ophthalmoplegia (CPEO) who underwent muscle biopsy for suspected mitochondrial disease. In spite of normal histocytochemical cytochrome c oxidase (COX) activity and respiratory chain enzyme measurements in muscle, subsequent molecular genetic analysis revealed the presence of a single, large-scale deletion of mitochondrial DNA (mtDNA). The case serves to illustrate the importance of pursuing the proposed mitochondrial genetic abnormality, even in patients with normal biopsy findings.     

Eccrine duct carcinoma of the eyelid mimicking meibomian carcinoma: clinicopathological study of a case

Eccrine duct carcinoma belongs to a group of malignant sweat gland tumors showing de novo eccrine differentiation, but without features of benign adnexal counterparts. They are therefore likely to be confused with visceral adenocarcinomas that have metastasized to the lid. These tumors require important diagnostic considerations when adenocarcinoma is encountered in the lid in the absence of a known primary tumor. We present the case of a 60-year-old man with a nodule in the right upper eyelid that was histopathologically diagnosed as eccrine duct carcinoma of the lid. The differential diagnosis of eccrine carcinomas based on light microscopy, enzyme histochemistry, and immunohistochemistry is discussed, and a list of the various malignant eccrine tumors reported in the lid is presented.     

Müller cells express the neuronal progenitor cell marker nestin in both differentiated and undifferentiated human foetal retina

Tritiated thymidine studies suggest that Müller cells are the last cells born in the retina, although several authors describe Müller cells throughout the retina from very early ages. In this study immunohistochemistry was used to identify progenitor and Müller cells in human foetal retina. Antibodies to nestin (an intermediate filament protein expressed by neural progenitor cells), vimentin, cellular retinaldehyde binding protein (CRALBP) and glutamate and aspartate transporter (GLAST), which are each expressed by Müller cells, were used in combination with anti-Ki67 to identify proliferating cells. By definition, Ki67-positive proliferating cells were present in undifferentiated retina, but not in differentiated retina. Nestin-immunoreactive (IR) cells colocalized with vimentin throughout the retina. CRALBP-IR was detected in differentiated retina and in some proliferating cells. GLAST-IR cells were present only within the differentiated region. Nestin, vimentin and CRALBP each colocalized with mitotic Ki67-IR cells, suggesting that in foetal retina Müller cells and retinal progenitor cells are overlapping populations and that Müller cells are end-stage progenitor cells.     

Glucose-6-phosphate dehydrogenase expression associated with NADPH-dependent reactions in cerebellar neurons

This review describes the variation of glucose-6-phosphate dehydrogenase (G6PD) activity in the main neurons of the molecular and granular layers as well as in the deep nuclei of the cerebellum as observed so far by optical and electron microscopy studies. Light microscopy and semiquantitative microphotometry of histochemical staining showed that the highest G6PD activity was expressed by Purkinje cells and neurons of the deep cerebellar nuclei; the elements of the molecular layer showed a diffuse G6PD staining, while the granular layer displayed only scattered G6PD activity. Electron microscopy analysis showed that the basket and stellate cells, as well as the Golgi cells, have a remarkable G6PD activity, while in the granule cells the enzyme was barely detectable. The results show that cerebellar G6PD activity changes with different neuron types as a function of its role in sustaining NADPH dependent pathways in these cells.     

Microglial ecto-Ca(2+)-ATPase activity in a rat model of focal homologous blood clot embolic cerebral ischemia: an enzyme histochemical study

Post-ischemic changes in ecto-Ca(2+)-ATPase activity in microglia and the infarcted tissue were studied in a rat model of focal embolic cerebral ischemia using an enzyme histochemical method. Ecto-Ca(2+)-ATPase activity was observed in whole brains in non-operated and sham-operated control animals. In addition, this enzyme activity was determined to be localized in ramified microglia. At 30 min after ischemia, non-microglial ecto-Ca(2+)-ATPase activity in the infarcted tissue slightly decreased and continued to decrease thereafter. The ecto-Ca(2+)-ATPase activity in microglia did not appear changed at this time. The decrease of enzyme activity in the infarcted tissue made it much easier to clearly observe ecto-Ca(2+)-ATPase-positive microglia. The enzyme activity of microglia in the ischemic area began to decrease 2 or 4h after embolization and remarkably decreased, except in the perinuclear cytoplasm, apical parts of the processes, and several parts along the processes, 8h after ischemia. By 12h after onset of embolization, the enzyme activity of microglia and infarcted tissue had almost completely disappeared. Ecto-Ca(2+)-ATPase of microglia is likely to play an important role in the metabolism of extracellular nucleotides in the ischemic area immediately after the onset of embolization by means of ecto-enzymes. Thus, the findings of the present study suggest that microglia might serve to protect the infarcted tissue in the ischemic brain.     

Lectin affinity of the seminiferous epithelium in healthy and cryptorchid post-pubertal boars

The present study describes the sugar content of the seminiferous epithelium, using lectin histochemistry, in healthy boars and in boars with unilateral and bilateral abdominal cryptorchidism. In healthy boars the apical cytoplasm of Sertoli cells exhibited abundant glucosyl (Con A and WGA lectins), galactosyl (HPA, DBA, SBA and PNA lectins), and fucosyl (AAA lectin) residues. Spermatogonia and spermatocytes contained abundant glucosyl (Con A and WGA lectins) and fucosyl (AAA lectin) residues. In spermatids, galactosyl (SBA and PNA lectins) and glucosyl (Con A and WGA lectins) residues increased progressively throughout spermiogenesis, and fucosyl (AAA lectin) residues decreased. As compared with healthy boars, the scrotal testis of unilateral cryptorchid boars showed decreased amounts of fucosyl (AAA lectin) and galactosyl (HPA and DBA lectins) residues on the Sertoli cell apical cytoplasm; spermatocytes exhibited higher content of glucosyl (Con A lectin) residues and spermatids showed altered nature of glucosyl (Con A and WGA lectins) and galactosyl (SBA and PNA lectins) complexes. In abdominal testes of unilateral and bilateral cryptorchid boars, immature Sertoli cells and spermatogonia showed decreased fucosyl (AAA lectin), and increased glucosyl (Con A and WGA lectins) and galactosyl (SBA and PNA lectins) contents. These results suggest that the seminiferous epithelium of healthy boars has polarized activity with the apical compartment implicated in germ cell-Sertoli cell adhesion and interaction, in transport of ions, substrates and fluids, and in acrosomal differentiation. In scrotal testes, unilateral abdominal cryptorchidism could lead to defective germ cell-Sertoli cell adhesion, impaired acrosomal differentiation and increased ionic transport in the apical compartment of the seminiferous epithelium. Unilateral and bilateral cryptorchidism could induce increased ionic transport and membrane permeability in the seminiferous epithelium of abdominal testes.