Chemically modified tetracyclines induce cytotoxic effects against J774 tumour cell line by activating the apoptotic pathway

Here, we have studied the effects of chemically modified tetracyclines (CMTs) on apoptosis both at the level of the cytoplasmic proteolytic caspase cascade, and on Bcl-2 and c-myc mRNA expression in the J774 macrophage cell line. The results indicate that CMTs induce morphological changes consistent with apoptotic events, as clearly demonstrated both by the acridine orange and ethidium bromide staining, and by TUNEL and fragmentation ELISA assays. Furthermore, the analysis of the cell cycle by flow cytometry shows an evident apoptotic sub-G0G1 peak, without important modifications in the cell cycle distribution. CMTs induce programmed cell death (PCD) in a dose-dependent manner and CMT-8 is the strongest among them. CMT-1 and CMT-8 activate mainly caspase-8 as attested by the inhibitory effects of Z-VAD-fmk and Z-IEDT-fmk on CMT-induced apoptosis. Part of CMT-induced PCD is due to the activation of caspase-9, since it is reduced by the specific caspase-9 inhibitor, Z-LEHD-fmk. Besides, CMTs increase Bcl-2 and c-myc mRNA expression. Collectively, these data indicate that CMTs are potentially anti-tumour agents, since they strongly trigger apoptosis both activating the proteolytic system of the caspase family and modulating genes involved in PCD regulation.     

15,21-Cyclowithanolides from Jaborosa bergii

Six new withanolides (1-6) were isolated from the aerial parts of Jaborosa bergii plants and characterized by spectroscopic methods (1D and 2D NMR, MS). Five of the new compounds presented a novel norbornane-type structure in ring D of the steroid nucleus (1-5), resulting from a carbon-carbon bond between C-15 and C-21. The sixth withanolide isolated was the 5alpha-chloro-6beta-hydroxy analogue (6) of 2,3-dehydrojaborosalactol M (7), previously isolated from this plant. Compound 1 showed selective phytotoxicity toward monocotiledoneous and dicotiledoneous species.     

Plasma membrane channels formed by connexins: their regulation and functions

Members of the connexin gene family are integral membrane proteins that form hexamers called connexons. Most cells express two or more connexins. Open connexons found at the nonjunctional plasma membrane connect the cell interior with the extracellular milieu. They have been implicated in physiological functions including paracrine intercellular signaling and in induction of cell death under pathological conditions. Gap junction channels are formed by docking of two connexons and are found at cell-cell appositions. Gap junction channels are responsible for direct intercellular transfer of ions and small molecules including propagation of inositol trisphosphate-dependent calcium waves. They are involved in coordinating the electrical and metabolic responses of heterogeneous cells. New approaches have expanded our knowledge of channel structure and connexin biochemistry (e.g., protein trafficking/assembly, phosphorylation, and interactions with other connexins or other proteins). The physiological role of gap junctions in several tissues has been elucidated by the discovery of mutant connexins associated with genetic diseases and by the generation of mice with targeted ablation of specific connexin genes. The observed phenotypes range from specific tissue dysfunction to embryonic lethality.     

Differences between endocarditis with true negative blood cultures and those with previous antibiotic treatment

BACKGROUND AND AIM OF THE STUDY: High morbidity and mortality are attributed to patients with culture-negative endocarditis. The main reason for negative blood culture in infectious endocarditis (IE) is administration of antibiotics before sample withdrawal. The study aim was to determine any difference in prognosis between patients with 'aborted' culture-negative endocarditis (A-CNE) and those with true culture-negative endocarditis (T-CNE). METHODS: A total of 107 patients with a diagnosis of IE was studied retrospectively. Diagnosis was confirmed pathologically during surgery, at post-mortem examination, or by fulfillment of Duke's criteria. Twenty patients (18.7%) had negative-culture endocarditis and comprised the study population. Of these patients, 14 (70%) had received previous antibiotic therapy (A-CNE), and six (30%) were considered T-CNE cases. In-hospital outcome and clinical characteristics were compared between both patient groups. The main end-point was death or need for surgical repair of the heart valves during hospitalization. RESULTS: There were no significant inter-group differences with respect to mean age, gender distribution, and other clinical characteristics. The composite endpoint of death or surgical repair occurred more frequently in T-CNE patients (100% versus 64%, p = 0.0394). Anatomic complications also occurred more frequently in T-CNE patients, but the difference was statistically not significant. CONCLUSION: Among patients with IE and a negative blood culture, those without previous antibiotic therapy (T-CNE) have the worse prognosis.     

Leptin as a marker of multiple sclerosis activity in patients treated with interferon-beta

The role of leptin was investigated in relapsing-remitting multiple sclerosis (MS). Control and MS patients showed comparable baseline serum leptin levels. During the first year of IFNbeta-1a treatment, leptin significantly decreased since 2 months after starting therapy in 11 patients who had no relapses. A significant decrease in IL12/IL10 ratio was observed in this group of patients only after 1 year of treatment. An increase of leptin was observed before the first clinical exacerbation in 13 relapsing patients. Leptin may play a pathogenic role in MS and can be a useful marker of disease activity and response to therapy.     

NF2 tumor suppressor gene: a comprehensive and efficient detection of somatic mutations by denaturing HPLC and microarray-CGH

The NF2 tumor suppressor gene, located in chromosome 22q12, is involved in the development of multiple tumors of the nervous system, either associated with neurofibromatosis 2 or sporadic ones, mainly schwannomas and meningiomas. In order to evaluate the role of the NF2 gene in sporadic central nervous system (CNS) tumors, we analyzed NF2 mutations in 26 specimens: 14 meningiomas, 4 schwannomas, 4 metastases, and 4 other histopathological types of neoplasms. Denaturing high performance liquid chromatography (denaturing HPLC) and comparative genomic hybridization on a DNA microarray (microarray- CGH) were used as scanning methods for small mutations and gross rearrangements respectively. Small mutations were identified in six out of seventeen meningiomas and schwannomas, one mutation was novel. Large deletions were detected in six meningiomas. All mutations were predicted to result in truncated protein or in the absence of a large protein domain. No NF2 mutations were found in other histopathological types of CNS tumors. These results provide additional evidence that mutations in the NF2 gene play an important role in the development of sporadic meningiomas and schwannomas. Denaturing HPLC analysis of small mutations and microarray-CGH of large deletions are complementary, fast, and efficient methods for the detection of mutations in tumor tissues.     

Six-week induction chemotherapy followed by concomitant chemoradiation therapy in stage IV head and neck cancer: a phase II study with organ-sparing purposes

The purpose of the study was to assess response rate, clinical outcome, organ/function preservation and toxicity in head and neck cancer patients treated with induction chemotherapy followed by concomitant chemoradiotherapy and, when necessary, limited surgery. The study was a phase II non-randomized trial. Induction chemotherapy consisted of 6 weekly doses of carboplatin at AUC of 2 and docetaxel 30 mg/m(2) (1 h) followed by 5 cycles of docetaxel 25 mg/m(2)/day 1, 5-FU 600 mg/m(2) c.i. days 1-5, hydroxyurea 500 mg orally every 12 h for 11 and concomitant twice daily radiation therapy at 150 cGy/fraction given every other week per 5 cycles (TFHX), for a total radiation dose of 75 Gy. 13 cis-retinoic acid was administered for chemoprevention and systematic prophylaxis of mucositis with systemic amifostine and local GM-CSF was administered to all patients during TFHX. Conservative surgical resection was reserved to patients with no optimal response (PR > or =70%), whereas radical surgery was performed as salvage treatment. Thirteen patients (mean age 54.9 years, range 44-62; 12/13 site oropharynx, all stage IV) were enrolled: 31% of patients had ECOG performance status (PS) 0 and 69% had PS 1. Response to induction chemotherapy was analyzed in 12 patients: 2/12 (16.7%) achieved a partial response (PR) for an overall response (ORR) of 16.7%, 10/12 (83.3%) achieved stable disease (SD). TFHX was administered to 7 patients: 2 patients (28.6%) had complete remission (CR), 1 patient (14.3%) had PR for an ORR of 42.9%, 3 patients (42.8%) had SD and 1 patient (14.3%) had PD. At the completion of TFHX, 1 patient underwent local therapy. The toxicity was mild and consisted in: grade 3/4 neutropenia (7.7%), anemia (23.1%), diarrhea (15.4%), mucositis (7.7%), neurotoxicity (7.7%) during induction chemotherapy. During TFHX only 42.8% of grade 3/4 mucositis was observed. All patients spared organ/function. In conclusion, this regimen has been found feasible for its acceptable toxicity, particularly mucositis. However, the overall response rate and the data on survival were not satisfactory.     

Ethynylestradiol increases expression and activity of rat liver MRP3.

We evaluated the effect of ethynylestradiol (EE) administration (5 mg/kg b.wt. s.c., for 5 consecutive days) on the expression and activity of multidrug resistance-associated protein 3 (Mrp3) in rats. Western blotting analysis revealed decreased Mrp2 (-41%) and increased Mrp3 (+200%) expression by EE. To determine the functional impact of up-regulation of Mrp3 versus Mrp2, we measured the excretion of acetaminophen glucuronide (APAP-glu), a common substrate for both transporters, into bile and perfusate in the recirculating isolated perfused liver (IPL) model. APAP-glu was generated endogenously from acetaminophen (APAP), which was administered as a tracer dose (2 micromol/ml) into the perfusate. Biliary excretion of APAP-glu after 60 min of perfusion was reduced in EE-treated rats (-80%). In contrast, excretion into the perfusate was increased by EE (+45%). Liver content of APAP-glu at the end of the experiment was reduced by 36% in the EE group. The total amount of glucuronide remained the same in both groups. Taken together, these results indicate that up-regulation of Mrp3 led to an exacerbated basolateral versus canalicular excretion of conjugated APAP in IPL. We conclude that induced expression of basolateral Mrp3 by EE may represent a compensatory mechanism to prevent intracellular accumulation of common Mrp substrates, either endogenous or exogenous, due to reduced expression and activity of apical Mrp2.     

Immunological studies in patients with central nervous system tumors

Impairment of cell-mediated immunity in patients with primary central nervous system (CNS) tumors has repeatedly been reported but data to demonstrate the underlying immunological defect are not univocal. This report concerns a series of 31 patients harboring a glioma in which we studied: peripheral blood T-lymphocyte subpopulations by monoclonal antibody analysis; cellular responsiveness to mitogens; serum immunoglobulin values. The same parameters were also evaluated in 7 cases of intracranial meningioma and in 8 patients affected by non-proliferative, non-inflammatory CNS diseases. Thirty age-matched healthy volunteers formed the control group. Neither impairment of T-cells as regard to number, responsiveness and subsets, nor abnormal Ig values were found in these groups. However two patients, harboring respectively a third ventricle low grade astrocytoma and an anterior callosal glioblastoma, presented a striking T-cells impairment. These findings might suggest a correlation between hypothalamus and immune system, as already postulated by several previous experimental and clinical studies.     

BRAF alterations are associated with complex mutational profiles in malignant melanoma

To evaluate the mutational profiles associated with BRAF mutations in human melanoma, we have studied BRAF, RAS, PTEN, TP53, CDKN2A and CDK4 genes and their expression in melanoma lesions. Owing to the lack of sufficient material from fresh specimens, we employed short-term cell lines obtained from melanoma biopsies. In all, 41 melanoma obtained from eight primary lesions, 20 nodal, 11 cutaneous and two visceral metastases from patients with sporadic (n=31), familial (n=4) and multiple melanoma (n=2) were analysed. The results revealed novel missense mutations in the BRAF, PTEN, CDKN2A and CDK4 genes. Overall, activating mutations of BRAF and loss of functional p16 and ARF were detected in the majority of melanomas (29/41, 36/41 and 29/41, respectively), while PTEN alterations/loss, NRAS and TP53 mutations occurred less frequently (6/41, 6/41 and 10/41, respectively). In the resulting 12 mutational profiles, p16/ARF loss associated with mutated BRAFV599E was the most represented (n=15). In addition, TP53 and PTEN mutations were always accompanied with BRAF alterations, while PTEN loss was found in association with CDKN2A or TP53 mutations in the absence of BRAF activation. The p16/ARFDelta+BRAF/RAS profile was significantly associated with a longer survival, while complex mutational profiles were detected in highly aggressive disease and poor survival. These data support the existence of several molecularly defined melanoma groups which likely reflect different clinical/biological behaviour, thus suggesting that a more extensive molecular classification of melanoma would significantly impact its clinical management.