Cadmium affects the redox state of rat liver glucocorticoid receptor

It has previously been documented that cadmium displays high affinity for protein thiol groups and induces an impairment of glucocorticoid receptor (GR) cellular functions. The present study examined the possibility that cadmium exerts these effects on GR activity by disturbing the receptor's redox equillibrium. To that end, the influence of cadmium on the rat liver GR potential to form intramolecular and intermolecular disulfide bonds under nonreducing conditions and under oxidizing conditions produced by the addition of hydrogen peroxide (H₂O₂) to the cytosol was examined by nonreducing SDS-PAGE and immunoblotting. The results show that cadmium inhibits formation of disulfide bonds within the GR both in the absence and in the presence of H₂O₂. The creation of intermolecular disulfide linkages between the apo-GR and associated heat shock proteins Hsp90 and Hsp70, which was evident in the presence of H₂O₂, was also significantly impaired after cadmium administration. These observations are consistent with the assumption that cadmium affects the redox state of the receptor, possibly by binding to its sulfhydryl groups. This revised version was published online in July 2006 with corrections to the Cover Date.     

Primary Rosai-Dorfman disease of bone without lymphadenopathy diagnosed by fine needle aspiration cytology. A case report

BACKGROUND: Solitary bone involvement without lymphadenopathy is a rare manifestation of Rosai-Dorfman disease, or sinus histiocytosis with massive lymphadenopathy (SHML). Only 11 cases have been reported in the literature to date, all diagnosed on histology. CASE: A 7-year-old girl had a radiolucent, lytic lesion in the shaft of the tibia clinically simulating Ewing's sarcoma. Fine needle aspiration cytology (FNAC) showed a microscopic picture typical--of SHML. There was no lymphadenopathy. CONCLUSION: Rosai-Dorfman disease sometimes involves bone without lymphadenopathy and can be diagnosed confidently on FNAC. To the best of our knowledge, this is the 12th case report of solitary bone involvement.     

The increased proliferation of cultured neuroblastoma cells treated with vasoactive intestinal peptide is enhanced by simultaneous inhibition of neutral endopeptidase

Vasoactive intestinal peptide (VIP) stimulates the neuroblastoma cell line (NMB) to proliferate. Neuropeptide activity can be inhibited by neutral endopeptidases that function intracellularly and in the extracellular milieu. NMB cells express neutral endopeptidase (NEP) activity that can be specifically inhibited by phosphoramidon (PA). Our data now show that phosphoramidon treatment increases the efficacy of VIP-stimulated neuroblastoma proliferation. These results suggest that membrane endopeptidases modulate VIP-associated cell proliferation and enhancement of endopeptidase activity may serve as a target for cancer therapy.     

In vitro and in vivo treatment of colon cancer by VIP antagonists

Vasoactive intestinal peptide (VIP) is secreted from many cancer lines and VIP binding was observed in many tumors. We have shown before that VIP antagonists are potent inhibitors of neoplastic growth of neuroblastoma, lung and breast cancer cells in vitro. Here, the cultured colon cancer cell line HCT-15 that exhibited VIP receptor expression was treated with the VIP hybrid antagonist neurotensin(6-11)VIP(7-28). The antineoplastic activity was assessed by thymidine incorporation. Neurotensin(6-11)VIP(7-28) efficiently inhibited cancer growth with a maximal effect at nanomolar concentrations. Once the inhibitory properties of the VIP antagonist on colon cancer cells were established, the in vivo curative effects were analyzed. Sprague-Dawley rats were injected with azoxymethane (AOM) (15 mg/kg/week) for 2 weeks, providing artificial induction of colon tumors. The rats were then allocated into four experimental groups: (1) receiving no treatment; (2) receiving treatment with saline; (3, 4) receiving treatment with 10 or 20 microg of neurotensin(6-11)VIP(7-28), respectively. After 10 weeks of daily injections, rats were sacrificed and tumors assessed for stage, volume, location, differentiation and lymphocytic infiltrate. Embedded mucosa was assessed for dysplastic crypts. Results showed that the antagonist treatment reduced the tumor volume, staging, lymphocyte infiltrate and the number of dysplastic crypts. Thus, neurotensin(6-11)VIP(7-28) could serve as an effective cancer treatment and a preventing agent.     

Ki-67 and AgNOR proliferative markers as diagnostic adjuncts to fine needle aspiration cytology of thyroid follicular lesions

OBJECTIVE: To differentiate hyperplastic nodules (HPN), follicular adenoma (FA) and follicular carcinoma (FCA) of the thyroid by cytomorphologic features combined with argyrophilic nucleolar organizer regions (AgNORs) and Ki-67 proliferative markers on fine needle aspiration cytology. STUDY DESIGN: Cytomorphologic patterns, along with two proliferation markers, Ki-67 and AgNORs, in fine needle aspirates of 123 histologically confirmed cases of thyroid follicular lesions, including 39 hyperplastic nodules, 70 follicular adenomas and 14 cases of follicular carcinomas, were recorded. RESULTS: Mean AgNOR (mAgNOR) counts and Ki-67 labelling index (LI) were consistently higher in FCA in comparison to FA and HPN irrespective of the cytologic patterns in fine needle aspiration smears. Between benign and malignant lesions, an overlap of 1.83% at the cutoff point of 4.0 was observed in cases of mAgNORs, whereas it was 11.09% at a cutoff of 5.0 in cases of Ki-67 LI. CONCLUSION: mAgNOR counting in fine needle aspiration smears is more sensitive, simple and cost effective as compared to Ki-67 LI for differentiating between benign and malignant thyroid follicular neoplasms.     

Six-membered cyclic ureas as HIV-1 protease inhibitors: a QSAR study based on CODESSA PRO approach. Quantitative structure-activity relationships

Quantitative structure-activity relationships (QSAR) for HIV-1 protease inhibitory activity of substituted tetrahydropyrimidinones have been produced using CODESSA PRO methodology and software. The best four-parameter equation (R(2)(cv)=0.847) allowed us to reveal two main structural factors which are strongly correlated with the title activity: molecular hydrophobicity and ability to form hydrogen bonds with the target enzyme.     

Mercury inhibits rat liver and kidney glucocorticoid receptor hormone binding activity

The present study was focused on the influence of mercury on the rat liver and kidney glucocorticoid receptor (GR) binding properties. The time-course and dose-dependence of mercury effects, as well as possible involvement of thiol groups were examined after in vivo and in vitro administration of the metal in the form of HgCl2. Mercury led to reduction of the liver and kidney GR hormone binding capacity. In both examined tissues maximal reduction was noticed 4 h after administration of the metal at 2 and 3 mg Hg/kg bw, but the effect was more prominent in kidney as compared to liver. On the other hand, binding affinity in the two tissues was similar. The complete reversal of mercury effects on GR binding capacity by 10 mmol/L DTT was achieved in liver and partially in kidney. The reversal by DTT suggested that mercury caused the decrease of GR binding activity by interacting with thiol groups. The difference in the response of the two tissues reflected the fact that kidney contained a higher mercury concentration and a lower thiol content in comparison to liver. The implicated thiols probably belong to GR, since when applied in vitro at 0 degrees C, mercury produced reduction of the receptor binding activity similar to that observed in vivo. GR protein level examined by quantitative Western blot was either unchanged, when determined by polyclonal antibody, or reduced, when determined by BuGR2 antibody, suggesting that Hg might affect BuGR epitope availability.