Activated status of tumour-infiltrating lymphocytes and apoptosis in testicular seminoma.

Testicular seminoma is characterized by a prominent lymphoid infiltrate and an excellent prognosis. Cytotoxic T-lymphocytes (CTLs) infiltrating seminoma tumour nests constitute a major subset of the lymphoid infiltrate. The objective of this study was to determine whether CTLs express markers of cytotoxic potential and activity and whether the number of activated CTLs correlates with the extent of apoptosis in testicular seminomas, as opposed to non-seminomatous testicular germ cell tumours (NSTGCTs). Twenty cases of pure seminoma as well as 20 cases of NSTGCTs including 16 mixed germ cell tumours (MGCTs) were studied. Immunohistochemistry for the cytotoxic markers TIA-1 (cytotoxic potential) and granzyme B (cytotoxic activity) and the T-cell markers CD3 and CD8 was performed on formalin-fixed, paraffin-embedded sections. The apoptotic index (AI) was determined by the TUNEL method. The number of CD3(+), CD8(+), TIA-1(+), and granzyme B(+) cells in tumour cell nests was markedly increased in testicular seminomas, compared with NSTGCTs (p<0.01). Activated granzyme B(+) cells numbered 25.6+/-5.2 per high power field in seminomas and 8.9+/-3.2, 8.1+/-3.9, and 0.4+/-0.2 for embryonal carcinomas, yolk sac tumours, and immature teratomas, respectively. Double immunohistochemical staining for granzyme B and CD8 revealed that 82.6+/-8.5% of granzyme B-expressing cells were CD8(+). The tumour cell AI was significantly increased in embryonal carcinoma, compared with the seminoma, yolk sac tumour, and immature teratoma subgroups (6.7+/-1.3, 2.3+/-0.3, 3.0+/-1.1, and 2.3+/-1.1, respectively, p<0.001). TUNEL/CD3 double immunostaining revealed that a significant proportion of the apoptotic seminomatous tumour cells were in direct contact with one or more CD3(+) lymphocytes (47.2+/-6.2%). The number of activated granzyme B(+) CTLs showed a strong linear correlation with the AI in the seminoma group (r=0.71, p<0.0001) but not in other subgroups. TUNEL/granzyme B double immunolabelling revealed that a proportion of activated granzyme B(+) lymphocytes (20%) were often seen in close contact with apoptotic tumour cells. The presence of increased numbers of activated cytotoxic lymphocytes in testicular seminomas suggests that apoptotic tumour cell death in this neoplasm may be triggered by cytotoxic granule effectors. This phenomenon may be one of the key host immune mechanisms leading to the excellent prognosis in this tumour.     

Apoptosis, proliferation, and Fas (APO-1, CD95)/Fas ligand expression in medullary carcinoma of the breast

Medullary carcinoma (MC) of the breast is a unique subtype of infiltrating ductal carcinoma that is characterized by a prominent lymphoid infiltrate and improved prognosis. Activated granzyme B(+)/CD8(+) cytotoxic T-lymphocytes (CTLs) infiltrating tumour cell nests constitute a major subset within the lymphoid infiltrate. As CTLs destroy target tumour cells by triggering apoptosis, it would be of interest to determine whether the apoptotic rate in MC is increased. This study evaluates the extent of apoptosis in relation to Fas (APO-1, CD95)/Fas ligand (FasL) expression in MC. Fourteen cases of typical MC (TMC) and 15 cases of atypical MC (AMC) classified according to the Ridolfi criteria, as well as 19 cases of poorly differentiated infiltrating ductal carcinoma (PDC) were evaluated. The apoptotic index (AI) was assessed by the TUNEL method on paraffin-embedded tissue. Cell proliferation was evaluated immunohistochemically by PCNA staining. The level of Fas/FasL expression was determined semiquantitatively by immunohistochemistry using a four-grade scoring system. The AI was significantly increased in TMC and AMC as opposed to the PDC subgroup (2.2+/-0.8, 2.1+/-0.8, and 1.3+/-0.6, respectively; p<0.05). A significant proportion (31.8+/-7.9% in TMC and 25.8+/-9.7% in AMC) of the apoptotic tumour cells within tumour nests were in close contact with CD3(+) lymphocytes. Increased apoptosis was not accompanied by increased proliferation of tumour cells. The extent of Fas expression did not differ between the three subgroups. FasL was expressed both by tumour infiltrating lymphocytes in MC and by tumour epithelium in all three subgroups. The observation that the majority of MCs express Fas and are infiltrated by lymphocytes expressing FasL suggests that increased apoptosis in MC is mediated by Fas/FasL. However, our observation that the majority of MCs also express FasL and the fact that tumours co-expressing Fas and FasL did not show increased apoptosis suggest that there may be additional cytotoxic pathways that lead to tumour apoptosis in MC.     

Abnormal deposition of collagen around hepatocytes in Wilson's disease is associated with hepatocyte specific expression of lysyl oxidase and lysyl oxidase like protein-2

BACKGROUND/AIMS: Lysyl-oxidases catalyze the oxidation of lysine residues in collagen and elastin thereby promoting their polymerization. We have studied here the expression of four lysyl-oxidases in normal and diseased human liver. METHODS: The expression of the different lysyl-oxidases in paraffin embedded liver sections was studied using in-situ hybridization and immunohistochemistry. The enzymatic activity of lysyl-oxidase like protein-2 (Loxl2 or LOR-1) using a previously described lysyl-oxidase assay. RESULTS: We have found that the four lysyl-oxidases which we examined are not significantly expressed in the normal liver. By contrast, Wilson's disease and primary biliary cirrhosis (PBC) patients express lysyl-oxidase (Lox) and lysyl-oxidase like protein-2 (Loxl2 or LOR-1) in hepatocytes, and the expression is accompanied by collagen deposition around the hepatocytes. Lysyl-oxidases are also expressed in additional fibrotic liver diseases such as hepatitis B and C but in these diseases the expression is confined to the fibrotic lesions and collagen does not accumulate around hepatocytes. We have found that Loxl2 is able to oxidize lysine residues of collagen, and behaves in that respect similarly to Lox. The copper chelator D-penicillamine inhibits Loxl2 induced oxidation of collagen but the Lox inhibitor beta-aminopropionitrile did not inhibit the oxidation using a BAPN concentration at which Lox activity was completely inhibited. Loxl2 also catalyzed the oxidation of cell surface proteins on HepG2 hepatoblastoma cells and inhibited their proliferation. CONCLUSIONS: Upregulation of Lox and Loxl2 in hepatocytes of Wilson's disease and PBC patients may contribute to liver damage by various mechanisms. The upregulation of Lox and Loxl2 in Wilson's disease could perhaps be utilized for diagnostic purposes since their expression is up-regulated in hepatocytes even before the onset of fibrosis.     

Reconstruction of acne keloidalis nuchae using osmotic tissue expanders—a case series

Background

Acne keloidalis nuchae (AKN) is a benign condition of keloid-like papules on the occipital scalp area. Treatment for AKN is divided into conservative and surgical. The use of tissue expander enables preservation of the hirsute area and thereby achieves a good cosmetic result. Osmotic tissue expander is a self-filling device, which absorbs tissue fluids in order to increase skin volume gradually. So far, the use of osmotic expander for reconstruction of AKN has not been described. We present our experience with five consecutive cases of tissue reconstruction using osmotic expanders in AKN.

Methods

Five patients suffering from AKN, median age of 43 years (range 35–50), who were admitted to our department between April 2010 and December 2011 underwent reconstruction using an osmotic tissue expander. All patients had the lesions for a median of 12 years (range 7–15).

Results

In three of the five patients, one expander was used per patient. In the remaining two, two expanders were used. In all the cases, the operative and postoperative management were uneventful with no major complications. A minor complication included partial extrusion of the expander (one patient), which caused an earlier conclusion of the reconstruction, nevertheless with a pleasing result. The average expansion period was 7 weeks (range 4–9). During that time, there was a median of one follow-up visit (range 1–2). Final aesthetic results were satisfactory in all the cases.

Conclusions

Osmotic expander is a reliable tool for tissue expansion. The main advantages of this device make it especially suitable for AKN reconstruction. Its main disadvantages include the inability to control the filling rate and the need to remove it in case of tissue damage. Level of Evidence: Level V, therapeutic study.     

A comparative study of immunohistochemistry and electron microscopy used in the diagnosis of epidermolysis bullosa

Electron microscopic examination still is the gold standard for classifying epidermolysis bullosa, although it is relatively expensive, time consuming, and not readily available. Immunoreagents have been developed recently to map antigens in the basement membrane on routinely processed specimens. The current study was performed to examine the diagnostic usefulness of immunohistochemistry, as compared with electron microscopic examination, for analyzing routine formalin-fixed paraffin-embedded sections of epidermolysis bullosa. This study investigated 39 consecutively diagnosed cases of epidermolysis bullosa in which both electron microscopic examination and immunohistochemistry were used. In each case, three monoclonal antibodies were used to stain for laminin 1, collagen IV, and keratin. The immunohistochemical patterns were defined as follows: epidermolysis bullosa simplex (laminin, collagen IV, or both at the dermal floor of the blister and keratin at both the dermal floor and the epidermal roof), junctional epidermolysis bullosa (laminin, collagen IV, or both at the dermal floor of the blister and keratin only at the epidermal roof), and dystrophic epidermolysis bullosa (collagen IV, laminin, or both, and keratin all at the epidermal roof). Altogether, electron microscopic examination subclassified epidermolysis bullosa into its three major forms in 37 of the 39 cases (95%), and immunohistochemistry in 33 of the 39 cases (85%). All of the classifiable cases were concordant. Specifically, immunohistochemistry was diagnostic in 10 of 14 (71%) epidermolysis bullosa simplex cases, 14 of 14 (100%) junctional epidermolysis bullosa cases, and 9 of 11 (82%) dystrophic epidermolysis bullosa cases. The most frequent cause for inconclusive immunohistochemical results was failure in staining of the basement membrane with the antibodies to both laminin and collagen IV. In conclusion, the use of immunohistochemistry on routinely processed specimens may be useful for subclassifying epidermolysis bullosa into its major forms in the majority of the cases, although it still cannot fully replace electron microscopic examination or immunofluorescence mapping in the diagnosis of epidermolysis bullosa.     

High-resolution electrophysiological assessment of human embryonic stem cell-derived cardiomyocytes: a novel in vitro model for the study of conduction

The goal of the present report was to establish a new in vitro model for the study of impulse propagation in human cardiac tissue. By using the human embryonic stem cell differentiating system, spontaneously contracting areas were generated in three-dimensional differentiating cell aggregates (embryoid bodies). Morphological analysis revealed an isotropic tissue of early-stage cardiac phenotype. Gap junctions, assessed by immunostaining of connexin43 and connexin45, were distributed along the cell borders. High-resolution activation maps demonstrated the presence of a functional syncytium with stable focal activation and conduction properties. Conduction was significantly slower in narrow bands of contracting tissue compared with broad cardiomyocyte regions. Establishment of this unique in vitro human model may be used for the assessment of long-term structure-function relationships, for pharmacological studies, for tissue engineering, and may permit the study of genetically modified cardiomyocytes.     

Distinctive patterns of gene expression in premalignant gastric mucosa and gastric cancer

Current epidemiological evidence supports a pathogenetic model of gastric cancer involving intermediate stages that include chronic gastritis and intestinal metaplasia. This study explores the molecular features of gastric cancer and premalignant stages using DNA microarray-based gene expression profiling and relates these findings to clinical, pathological, and ethnic parameters. A total of 124 tumor and adjacent mucosa samples were analyzed using spotted cDNA microarrays containing 9381 nonredundant gene elements. Tumor specimens were diffuse, intestinal, or mixed gastric cancer and adjacent mucosa, which generally displayed signs of chronic gastritis or intestinal metaplasia. Expression patterns could be discerned that readily defined premalignant and tumor subtypes. Chronic gastritis exhibits a pronounced mitochondrial gene expression signature, which may be linked to Helicobacter pylori pathogenesis. Intestinal metaplasia was associated with increased expression of many intestinal differentiation genes, many of which were not overexpressed in tumors. Samples were obtained from 91 Australian and 33 Chinese patients to explore potential variation in gene expression between these populations. Despite differences in the incidence, and potentially the etiology, of gastric cancer between these ethnic groups, we found the tumors to be molecularly similar. The identification of molecular signatures that are characteristic of subtypes of gastric cancer and associated premalignant changes should enable further analysis of the steps involved in the initiation and progression of this disease.