Ella Kaganovsky

A second isoform of gonadotropin-releasing hormone is present in the brain of human and rodents

Gonadotropin‐releasing hormone‐I (GnRH‐I), present in the mammalian hypothalamus, regulates reproduction. In this study we demonstrate, for the first time, that an additional isoform of GnRH, [His5, Trp7, Tyr8] GnRH‐I (GnRH‐II) is present in the brain of the mouse, rat and human. Human and rat brain extracts contain two isoforms of GnRH, GnRH‐I and GnRH‐II, which exhibited identical chromatographic properties to the respective synthetic peptides, in high performance liquid chromatography. Using immunohistochemical techniques we have found that GnRH‐II is present in neuronal cells that are localized mainly in the periaqueductal area as well as in the oculomotor and red nuclei of the midbrain. It is of interest to note that in the hypogonadal mouse, although the GnRH‐I gene is deleted, GnRH‐II is present. Substantial concentrations of GnRH‐II are also present in the hypothalamus and stored in the human pituitary stalk or in the mouse median eminence. By using reverse transcription (RT)‐PCR we have also found that while GnRH‐II is not expressed in the cerebellum, it is expressed in all three structures of the brain stem: midbrain, pons and medulla oblongata.

The gonadotropin‐releasing hormone family of neuropeptides in the brain of human, bovine and rat: identification of a third isoform

The mammalian gonadotropin‐releasing hormone (GnRH‐I), which regulates reproduction, was the first isoform of GnRH that was identified in mammals. Recently, we and others have demonstrated the existence of a second isoform of GnRH in the brain of mammals. The presence of a third isoform of GnRH, GnRH‐III, in the brain of mammals is reported herein. GnRH‐III, extracted from the brain of bovine and human, was purified by high performance liquid chromatography, using two distinct elution programs. In both, GnRH‐III was eluted at the same positions as synthetic salmon GnRH, as demonstrated by radioimmunoassay. The luteinizing hormone‐releasing activity of purified GnRH‐III, using dispersed rat pituitary cells, was found to be similar to that of synthetic salmon GnRH. The total amount of GnRH‐III, determined by radioimmunoassay, in the hypothalamus and midbrain of humans and calves is similar to that of GnRH‐I. Immunohistochemical studies demonstrated GnRH‐III‐containing neurons in the hypothalamus and midbrain of human and GnRH‐III fibers in the median eminence of rats. The distribution of GnRH‐III in the brain suggests that in addition to a putative function as a neurohormone at the hypothalamic–pituitary axis, GnRH‐III may have other functions. Our present results suggest that multiple isoforms of GnRH are present in the brain of mammals, and further studies are required in order to elucidate their biological functions.

c-kit expression in primary and metastatic merkel cell carcinoma.

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine tumor of the skin that is associated with a high incidence of recurrence and metastasis. The therapeutic arsenal for this malignancy is limited and once it spreads, there is no effective treatment. c-kit expression has been demonstrated previously in primary MCCs thus raising the possibility of treating MCCs with imatinib mesylate, the tyrosine kinase inhibitor that has shown promise in the management of c-kit expressing tumors. In this study we examine 25 additional primary MCCs and also 6 of their lymph node metastases. Formalin-fixed, paraffin-embedded tissues were stained immunohistochemically with an antibody directed against the KIT receptor. Percentage and intensity of staining were analyzed semiquantitatively using a three-tiered system. Twenty-one of the 25 (84%) primary tumors stained positively for KIT, of which 14 (67%) showed widespread positivity. Five of the 6 lymph nodes (83%) were similarly positive. High mitotic rate and vascular invasion in the primary tumors tended to be associated with prominent staining in the lymph node metastases. No association was found between c-kit expression and outcome. We confirm that the majority of primary MCCs express c-kit and further find that metastases are positive for the KIT receptor as well. Thus, c-kit expression may be an early event in the transformation of MCC, but not a marker for tumor progression.

MONOCLONAL ANTI-ENDOTHELIAL CELL ANTIBODIES FROM A PATIENT WITH TAKAYASU ARTERITIS ACTIVATE ENDOTHELIAL CELLS FROM LARGE VESSELS

OBJECTIVE To create monoclonal anti-endothelial cell antibodies (mAECA) from a patient with Takayasu arteritis to evaluate their ability to activate human umbilical vein endothelial cells (HUVEC), and to characterize the mechanism of EC activation. METHODS A panel of mAECA was generated from peripheral blood lymphocytes of a patient with Takayasu arteritis, using Epstein-Barr virus transformation. Activity against macrovascular EC (HUVEC) and microvascular EC (human bone marrow EC immortalized by SV40) antigens was detected by enzyme-linked immunosorbent assay. Inhibition studies were used to select the monoclonal antibodies (mAECA) which share the same EC epitope binding specificity as the total IgG-AECA from the Takayasu arteritis patient. The binding of the mAECA to human aortic EC was studied by immunohistochemistry. The secretion levels of interleukin-6 (IL-6) and von Willebrand factor (vWF) were determined, to serve as markers for EC activation. The activated EC were examined for the adherence of a monocytic cell line (U937), as well as for expression of vascular cell adhesion molecule 1, intercellular adhesion molecule 1, and E-selectin. In addition, nuclear extracts of the mAECA-treated EC were analyzed for the induction of translocation of nuclear factor kappaB (NF-kappaB), using a specific NF-kappaB oligoprobe in an electrophoretic mobility shift assay. RESULTS Six mAECA were selected, the mixture of which produced 100% inhibition of binding of the original IgG (from the patient with Takayasu arteritis) to HUVEC. All mAECA possessed high activity against macrovascular EC, but none had significant antimicrovascular EC activity. The mAECA, but not normal human IgG, had anti-human aortic EC activity. Four of the 6 mAECA activated EC, manifested by increased IL-6 and vWF secretion. The 4 mAECA induced EC expression of adhesion molecules and increased adhesion of U937 monocytic cells to EC. In addition, these mAECA stimulated the nuclear translocation of the NF-kappaB transcription factor. CONCLUSION Our findings suggest that AECA may directly stimulate EC in Takayasu arteritis through elevation of adhesion molecule expression associated with NF-kappaB activation and adhesion of monocytes, and may therefore play a pathogenic role in the development of the vasculopathy in Takayasu arteritis.

Different patterns of expression of the erbB family of receptor tyrosine kinases in common nevi, dysplastic nevi, and primary malignant melanomas: an immunohistochemical study.

erbB receptors contribute to tumor formation and progression. Variable expression of erbB1, erbB2, and erbB3 has been reported in nevi and melanomas; erbB4 has hardly been investigated. We examined the expression of all 4 erbB receptors in common and dysplastic nevi and melanomas. Formalin-fixed, paraffin-embedded tissues of 100 melanomas, 27 common nevi, and 23 dysplastic nevi were immunostained with antibodies against the 4 erbB receptors. erbB3 and erbB4 showed stronger positivity in nevi than in melanomas, and in common than in dysplastic nevi. Staining pattern was more orderly in nevi than in melanomas. Common nevi showed more prominent membranous staining for erbB3 than dysplastic nevi followed by melanomas. In melanomas, greater thickness was associated with more widespread erbB2 and erbB3 staining in the vertical than in the radial growth phase, and in the dermal than in the epidermal component. Higher mitotic counts were associated with more widespread and intense erbB2 expression in the vertical growth phase than in the radial growth phase and in the dermal than in the epidermal component. Melanomas with more widespread erbB2 staining had heavier lymphocytic infiltrates. erbB1 expression was negligible in all groups. erbB2, erbB3, and erbB4 are expressed in all subtypes of melanocytic lesions, but with quantitative and qualitative differences. Receptor expression seems to decrease and to become less mature and orderly with tumor progression. The complex patterns of erbB receptor expression in melanocytic lesions warrant further investigation.

The Placental Barrier in Allogenic Immune Conflict in Spontaneous Early Abortions: Immunohistochemical and Morphological Study

Morphologic changes in the placental barrier in spontaneous early abortions under the maternal‐embryonic immune conflict, and the role of maternal immunoglobulins (Igs) in these changes.

Pathomorphologic and immunohistochemical study on the devastation of rat embryos by antiphospholipid antibody positive serum.

Problem  While relying on previous publications, our aim was to examine the morphologic changes, induced in early rat embryos by intra‐uterine exposure to the low‐molecular weight fraction of boiled human serum containing antiphospholipid antibodies (APLA) that had been obtained from women with antiphospholipid syndrome (APS).

ORIGINAL ARTICLE: Pathomorphologic and Immunohistochemical Study on the Devastation of Rat Embryos by Antiphospholipid Antibody Positive Serum: DETRIMENTAL EFFECT OF APLA SERUM

Problem  While relying on previous publications, our aim was to examine the morphologic changes, induced in early rat embryos by intra‐uterine exposure to the low‐molecular weight fraction of boiled human serum containing antiphospholipid antibodies (APLA) that had been obtained from women with antiphospholipid syndrome (APS).

ORIGINAL ARTICLE: Pathomorphologic and Immunohistochemical Study on the Devastation of Rat Embryos by Antiphospholipid Antibody Positive Serum

Problem  While relying on previous publications, our aim was to examine the morphologic changes, induced in early rat embryos by intra‐uterine exposure to the low‐molecular weight fraction of boiled human serum containing antiphospholipid antibodies (APLA) that had been obtained from women with antiphospholipid syndrome (APS).