Immunohistochemistry in tumour diagnosis

Treating TB human neuroectodermal cell line with retinoic acid induces the appearance of neuron-like voltage-gated ionic currents

TB is a cell line derived from the cerebrospinal fluid sample of a patient with primary leptomeningeal melanomatosis. Our previous immunological and ultrastructural analysis revealed that TB cells differentiate towards a neuronal phenotype when grown in vitro up to 7 days in presence of 10 µM all-trans retinoic acid (RA). Recently, we reported that TB cells are sensitive to the cytotoxic effects of β-amyloid peptides, activating the cytosolic phospholipase A2. To date, it is not known if RA, in addition to inducing morphological changes, also causes functional modification in TB cells, by regulating voltage-gated ionic currents. To this purpose, we performed electrophysiological characterization of undifferentiated (TB) and differentiated (RA-TB) cells by means of whole-cell patch clamp recordings. Upon depolarizing stimuli, both groups displayed voltage-gated K⁺ outward currents of similar amplitude. By contrast, the low amplitude voltage-gated Na⁺ currents recorded in undifferentiated TB cells were largely up-regulated by RA exposure. This current was strongly reduced by TTX and lidocaine and completely abolished by removal of extracellular sodium. Furthermore, treatment with RA caused the appearance of a late-onset inward current carried by Ca²⁺ ions in a subpopulation of TB cells. This current was not affected by removal of extracellular Na⁺ and was completely blocked by Cd²⁺, a broad-spectrum blocker of Ca²⁺ currents. Altogether, our results indicate that RA-differentiation of TB cells induces functional changes by augmenting the amplitude of voltage-gated sodium current and by inducing, in a subpopulation of treated cells, the appearance of a voltage-gated calcium current.

Microvascular morphometrics of the hypophysis and pituitary tumors: from bench to operating theatre

The idea that microvasculature might be a histopathological biomarker in the prognosis and treatment of tumors is garnering even more attention in the scientific community. The roles of neovascularity in tumor progression and metastasis, have become a hot-topic of investigation in cancer research. A number of methods of quantitatively analyzing pituitary adenoma microvasculature have been applied, and fractal analysis is emerging as a potential effective model for this aim. Additionally, new and more specific immunological techniques have been developed for the detection of microvessels. CD105 (Endoglin) has been proposed as a valuable antigen that marks only newly formed vessels, rather than the entire tumor microvascular system. The combination of different types of immunostaining techniques for the detection of microvessels in pituitary adenomas with fractal analysis as an objective and computer-aided technique to quantify and describe morphological aspects of microvessels has potential implications in future clinical and surgical applications. Tumor treatments, such as anti-angiogenic therapy, as well as intraoperative tools, stand to be enhanced by increasing advances in microvascular research. We here review the methods used for the quantitative analysis of microvessels of the pituitary in its physiopathological states, with the aim to show the pituitary adenoma as a model for the study of neoplastic angioarchitecture and the importance of the introduction of new techniques for the study of angiogenesis, with the relative scientific, medical and surgical implications.

In vivo experimental model of human gingival mucosa using immunodeficient mice

BACKGROUND AND OBJECTIVE

To establish an in vivo experimental model for examining human periodontal tissue, the present study examined several transplant techniques that maintain the structure and characteristics of human gingival mucosa.

MATERIAL AND METHODS

Human oral mucosal tissue samples were collected from the gingiva (n = 11), palate (n = 1), and tongue (n = 3). These mucosal grafts were transplanted onto BALB/c nu/scid mice with double-mutant immunodeficiency. Murine skin, twice the size of the graft, was cut open in an ' square superset'-shape. Next, the connective tissue side of the graft was placed onto the murine connective tissue. Immunohistochemical analysis was also performed, using polyclonal rabbit antibody to involucrin, monoclonal antibody to vimentin, monoclonal antibody to CD34, and monoclonal antibody to Ki-67, to determine whether the characteristics of human oral mucosa were maintained.

RESULTS

When the connective tissue side of the graft was placed on the murine fascial membrane, the histological structure of the graft was maintained for 60 d. These grafts were examined for human characteristics using human-specific antibodies. Immunohistochemically, the expression patterns of involucrin, vimentin, and Ki-67 indicated that transplanted mucosa revealed normal human characteristics, including differentiation and proliferation up to 80 d. CD34 was not detected in the graft endothelial cells.

CONCLUSION

The present study revealed that the novel technique of transplantation of human gingival mucosa in nu/scid mice may serve as an in vivo experimental model of periodontal disease.

"Cutaneous-type" angiosarcoma arising in a mature cystic teratoma of the ovary

Benign and malignant somatic tumours arising in mature cystic teratomas of the ovary are a rare but recognised phenomenon. Squamous cell carcinoma is the most common somatic malignancy arising in ovarian teratomas, although many other types of tumour have been described. An angiosarcoma with "cutaneous" type typical features arising in a dermoid cyst of the ovary is reported. Vascular tumours have only rarely been described as secondary somatic tumours in ovarian teratomas. The diagnostic features and complications of such tumours are described.

The use of cytochemistry, immunophenotyping, flow cytometry, and in vitro differentiation to determine the ontogeny of a canine monoblastic leukemia

We evaluated the utility of cytochemistry, immunophenotyping, flow cytometry, and in vitro culture with forced differentiation of leukemic cells as diagnostic aids to identify the malignant cell ontogeny in a dog with leukemia. A tentative diagnosis of monoblastic leukemia was established by microscopic examination of Romanowsky-stained blood smears and bone marrow aspirate smears. This diagnosis also was supported by the light scatter signature that identified the blast cells as large, non-granular monocytic cells using a CellDyn 3500 automated hematology analyzer; as well as by the detection of N-butyrate esterase and the lack of choloroacetate esterase or leukocyte peroxidase by cytochemical staining. Subsequently, leukemic cells were isolated from the dog's peripheral blood and placed into tissue culture or cryopreserved. The leukemic cells grew in suspension cultures and proliferated spontaneously for up to 4 days. By day 7, proliferation was negligible. Upon culture with conditioned supernatant using mitogen-stimulated human T cells as a source of cytokines, an increased proportion of cells entered S phase by day 2 of culture; however, proliferation declined markedly by day 4, at which time the cells had apparently differentiated to adherent, vacuolated macrophages. The cytokine-stimulated leukemic cells were positive for the monocyte/macrophage specific markers alpha-1-antitrypsin, alpha-1-antichymotrypsin, lysozyme, CD14, MHC class II, and calprotectin, an antigen found in differentiated macrophages and granulocytes. Despite the strong tendency of the leukemic cells towards monocytic differentiation, our results suggested that they retained some features of a myelomonocytic precursor. These data show that cytochemistry, immunophenotyping, flow cytometry, and in vitro differentiation of canine leukemia cells are useful tools for confirming the lineage of malignant hematopoietic cells.

Cultured human fibroblasts in agarose gel as a multi-functional control for immunohistochemistry. Standardization Of Ki67 (MIB1) assessment in routinely processed urinary bladder carcinoma tissue

Immunohistochemistry (IHC) in clinical practice is hampered by lack of standardization and by subjectivity in interpretation and quantitation. This study aimed to develop a control system for IHC in routinely fixed and histoprocessed tissues. Such a system should be easy to handle in clinical practice and should reflect variations in fixation time, section thickness, section storage conditions, and staining protocols. In addition, in image analysis quantitation of immunostained tissues, when using classifiers computed on IHC-control images, the control system should be very stable. Cultured human fibroblasts were suspended in agarose, transferred into a length of tubing and stored at 4 degrees C. Three pieces of the cellgel control were separately fixed, histoprocessed, and paraffin-embedded as external controls. One piece was prepared together with each of 18 bladder carcinoma biopsies as internal controls. Slides with sections from the biopsy and all types of cellgel controls were stored at different temperatures and then stained using three different IHC protocols. The fibroblasts were homogeneously distributed in the agarose gel. Variation in section thickness did not influence immunostaining as evaluated by the MIB1 labelling index (MIB1 LI). The external controls decreased notably in MIB1 LI with increased fixation time. This was not seen in the 18 internal controls that were each fixed with a fresh biopsy. However, section storage and immunostaining conditions influenced the MIB1 expression equally in all control types and to a similar degree to the biopsies. Furthermore, colour-based image analysis quantitation of MIB1 LI in biopsies proved stable and independent of the control type used to compute the classifier.

Establishment and characterization of a human neuroectodermal cell line (TB) from a cerebrospinal fluid specimen

We have established a cell line (TB) from a cerebrospinal fluid (CSF) specimen of a patient with a primary leptomeningeal melanomatosis. TB cell line was immunoreactive with the antibodies for low molecular weight neurofilament protein, vimentin, neuron-specific enolase, chromogranin, synaptophysin and HMB-45 (an antibody sensitive and specific for melanoma). When TB cells were transplanted into nude mice, the same immunohistochemical pattern present in cultured cells was found but surprisingly, a positive staining for desmin was observed. Significant amounts of serotonin and its metabolite were detectable. Retinoic acid but not nerve growth factor was able to induce differentiation towards a neuronal phenotype. In summary, TB cells represent primitive neuroectodermal cells having the potential for neuronal, myoblastic and possibly melanoblastic differentiation.