Psychotropic analgesic nitrous oxide for alcoholic withdrawal states.

BACKGROUND: Alcoholism is a global problem with 5-10% of the world's population demonstrating alcohol-related diseases. One of the most severe consequences of alcohol dependence is the withdrawal syndrome, for which benzodiazepines are the most popular current treatment. An alternative method to benzodiazepine employs psychotropic analgesic nitrous oxide (PAN). OBJECTIVES: To assess the effects of PAN for treating alcohol withdrawal states SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 2, 2005), MEDLINE, EMBASE, CINAHL (all to May 2005). We scanned internet websites, reference lists of relevant articles and abstracts of the international Conferences on Alcoholism. We contacted researchers in the field and industry to identify unpublished trials. No language and publication restrictions. SELECTION CRITERIA: Randomised controlled trials including voluntary participants dependent on alcohol. PAN was compared to oxygen and/or benzodiazepine regimens. DATA COLLECTION AND ANALYSIS: Two authors independently assessed the methodological quality of the trials and extracted data. MAIN RESULTS: Five studies, 212 participants, were included. PAN showed improvement of symptoms (RR 1.35; 95% CI 1.01 to 1.79), of the amount and duration of sedative medication and of psychomotor function (WMD -8.71; 95% CI -13.71 to -3.71). At one hour post intervention, no significant differences were found for depression (WMD -2.40; 95% CI -8.70 to 3.89) and anxiety (WMD -3.70; 95% CI -10.53 to 3.12). None of the included studies reported any significant adverse effects of any treatment. AUTHORS' CONCLUSIONS: Results indicate that PAN may be an effective treatment of the mild to moderate alcoholic withdrawal state. The rapidity of the therapeutic effect of PAN therapy coupled with the minimal sedative requirements, may enable patients to enter the psychological treatment phase more quickly than those on sedative regimens, accelerating the patients recovery. Our review does not provide strong evidence due to the small sample sizes of the included trials. Neither does the review indicate any causes for concern that PAN is more harmful than the benzodiazepines. Clinicians wishing to use PAN may initially wish to do so within trial settings. Further high quality trials should be done to confirm these findings and to investigate whether the PAN therapy has fewer adverse effects than other treatments for the alcohol withdrawal states. Studies to investigate the possible cost-effectiveness of PAN by reducing costly hospital admissions and decreasing post administration supervision also need to be performed.

Antiretroviral post-exposure prophylaxis (PEP) for occupational HIV exposure.

BACKGROUND: Populations such as healthcare workers (HCWs), injection drug users (IDUs), and people engaging in unprotected sex are all at risk of being infected with the human immunodeficiency virus (HIV). Animal models show that after initial exposure, HIV replicates within dendritic cells of the skin and mucosa before spreading through lymphatic vessels and developing into a systemic infection (CDC 2001). This delay in systemic spread leaves a "window of opportunity" for post-exposure prophylaxis (PEP) using antiretroviral drugs designed to block replication of HIV (CDC 2001). PEP aims to inhibit the replication of the initial inoculum of virus and thereby prevent establishment of chronic HIV infection. OBJECTIVES: To evaluate the effects of antiretroviral PEP post-occupational exposure to HIV. SEARCH STRATEGY: The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, AIDSearch, and the Database of Abstracts of Reviews of Effectiveness were searched from 1985 to January 2005 to identify controlled trials. There were no language restrictions. Because no controlled clinical trials were retrieved, the search was repeated on 31 May 2005 in MEDLINE, AIDSearch and EMBASE using a search strategy to identify analytic observational studies. Handsearches of the reference lists of all pertinent reviews and studies found were also undertaken. Experts in the field of HIV prevention were contacted. SELECTION CRITERIA: Types of studies: All controlled trials (including randomized clinical trials and controlled clinical trials). If no controlled trials were found, analytic studies (e.g. cohort and case-control studies) were considered. Descriptive studies (i.e. studies with no comparison groups) were excluded. Types of participants included:HCWs exposed to any known or potentially HIV contaminated product;anyone exposed to a needlestick contaminated by known or potentially HIV-infected blood or other bodily fluid in an occupational setting; andanyone exposed through the mucous membranes to an HIV-infected or potentially infected substance in occupational setting.Excluded: Sex workers (PEP post-sexual exposure is addressed in another Cochrane review (Martín 2005)). Types of interventions: Any intervention that administered single or combinations of antiretrovirals as PEP to people exposed to HIV through percutaneous injuries and/or occupational mucous membrane exposures when the HIV status of the source patient was positive or unknown. Studies comparing two types of PEP regimens were considered, as were studies comparing PEP with no intervention. Types of outcome measures:Incidence of HIV infection in those given PEP versus those given placebo or a different PEP regimen; Adherence to PEP; Complications of PEPTypes of outcome measures: Incidence of HIV infection in those given PEP versus those given placebo or a different PEP regimen; Adherence to PEP; Complications of PEP DATA COLLECTION AND ANALYSIS: Data concerning outcomes, details of the interventions, and other study characteristics were extracted by two independent authors (TY and JA) using a standardized data extraction form (Table 04). A third author (GK) resolved disagreements. The following information was gathered from each included study: location of study, date, publication status, demographics (e.g. age, gender, occupation, risk behavior, etc.) of participants/exposure modality, form of PEP used, duration of use, and outcomes. Odds ratios with a 95% confidence interval (CI) were used as the measure of effect. A meta-analysis was performed for adverse events where two-drug regimens were compared with three-drug regimens. Due to overlap between Puro 2000 and Puro 2005, the former was not included in the combined analysis. MAIN RESULTS: Effect of PEP on HIV seroconversionNo randomized controlled trials were identified. Only one case-control study was included. HIV transmission was significantly associated with deep injury (OR 15, 95% CI 6.0 to 41), visible blood on the device (OR 6.2, 95% CI 2.2 to 21), procedures involving a needle placed in the source patient's blood vessel (OR 4.3, 95% CI 1.7 to 12), and terminal illness in the source patient (OR 5.6, 95% CI 2.0 to 16). After controlling for these risk factors, no differences were detected in the rates at which cases and controls were offered post-exposure prophylaxis with zidovudine. However, cases had significantly lower odds of having taken zidovudine after exposure compared to controls (OR 0.19, 95%CI 0.06 to 0.52). No studies were found that evaluated the effect of two or more antiretroviral drugs for occupational PEP. Adherence to and complications with PEPEight reports from observational comparative studies confirmed findings that adverse events were higher with a three-drug regimen, especially one containing indinavir. However, discontinuation rates were not significantly different. AUTHORS' CONCLUSIONS: The use of occupational PEP is based on limited direct evidence of effect. However, it is highly unlikely that a definitive placebo-controlled trial will ever be conducted, and, therefore, on the basis of results from a single case-control study, a four-week regimen of PEP should be initiated as soon as possible after exposure, depending on the risk of seroconversion. There is no direct evidence to support the use of multi-drug antiretroviral regimens following occupational exposure to HIV. However, due to the success of combination therapies in treating HIV-infected individuals, a combination of antiretroviral drugs should be used for PEP. Healthcare workers should be counseled about expected adverse events and the strategies for managing these. They should also be advised that PEP is not 100% effective in preventing HIV seroconversion. A randomized controlled clinical trial is neither ethical nor practical. Due to the low risk of HIV seroconversion, a very large sample size would be required to have enough power to show an effect. More rigorous evaluation of adverse events, especially in the developing world, are required. Seeing that current practice is partly based on results from individual primary animal studies, we recommend a formal systematic review of all relevant animal studies.

Intact vitronectin induces matrix metalloproteinase-2 and tissue inhibitor of metalloproteinases-2 expression and enhanced cellular invasion by melanoma cells.

The initial site of melanoma cell metastasis is frequently the regional lymph nodes, and the appearance of lymph node metastasis correlates with poor prognosis. Lymph node adhesion is mediated by an interaction between the tumor cell integrin alphavbeta3 and lymph node vitronectin. In this study, we explored the relationship between adhesion and proteolysis by examining the direct effect of vitronectin receptor ligation on matrix metalloproteinase-2 (MMP-2) production by B16F1 and B16F10 melanoma cells. We report a dose-dependent increase in secretion of both MMP-2 and tissue inhibitor of metalloproteinases-2 (TIMP-2) in response to vitronectin. Cellular invasiveness was also enhanced by vitronectin, as shown by the increased ability of vitronectin-treated cells to invade a synthetic basement membrane (Matrigel). Both the vitronectin-induced MMP-2 production and vitronectin-enhanced invasion were blocked by the peptide ligand Arg-Gly-Asp-Ser (RGDS). Furthermore, neither plasmin-degraded vitronectin nor the peptide ligand RGDS stimulated MMP-2 secretion or invasiveness, indicating that a multivalent ligand-receptor interaction rather than simple receptor occupancy was required for MMP-2 induction. MMP-2 and MMP-2/TIMP-2 interaction with the plasma membrane of melanoma cells resulted in enhanced catalytic activity against 14C-labeled gelatin, suggesting that membrane association may function in posttranslational regulation of MMP-2 activity. This is supported by data showing increased cellular invasion by cells containing membrane-bound MMP-2. Binding of proMMP-2 and proMMP-2/TIMP-2 to melanoma cells was not inhibited by RGDS, and melanoma cell adhesion to vitronectin was unaffected by pro- or active MMP-2, indicating that MMP-2 did not interact with the murine vitronectin receptor. Together, these data provide evidence for a functional link between adhesion and proteolysis and suggest a potential mechanism whereby adhesion of an invasive cell to the extracellular matrix regulates subsequent invasive behavior.

Fluorescence quenching studies of matrix metalloproteinases (MMPs): evidence for structural rearrangement of the proMMP-2/TIMP-2 complex upon mercurial activation.

Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases which are secreted from cells as zymogens and can be activated by treatment with organomercurial reagents or limited proteolysis. The proenzyme forms of MMP-2 (gelatinase A) and MMP-9 (gelatinase B) are found in complex with tissue inhibitor of metalloproteinases (designated proMMP-2/ TIMP-2 and proMMP-9/TIMP-1, respectively). The proposed mechanism of activation by mercurial compounds involves the induction of a conformational change in the zymogen which leads to propeptide autoprocessing. To investigate the possibility of conformational differences in MMPs, solute quenching of MMP intrinsic fluorescence was used to probe the relative exposure of tryptophan residues in latent and mercurial-activated MMPs. Our data demonstrate that fluorescence quenching of the proMMP-2/TIMP-2 complex by either acrylamide or iodide is significantly increased following mercurial activation. In contrast, no significant change in tryptophan accessibility accompanies mercurial treatment of either proMMP-2 or TIMP-2 alone, or mercurial-activated MMP-2 mixed with TIMP-2. To determine whether the enhanced fluorescence quenching was unique to the activated proMMP-2/TIMP-2 complex, similar experiments were performed using MMP-1, MMP-3, and MMP-9/TIMP-1 complex. In all cases, both latent and mercurialtreated MMPs exhibited similar fluorescence quenching profiles, suggesting that there are no significant conformational differences between the zymogen and activated forms of MMP-1, -2, -3, or -9/TIMP-1. The enhanced fluorescence quenching observed with mercurial-treated proMMP-2/TIMP-2 is indicative of increased exposure of a previously buried tryptophan residue(s), providing evidence for a structural rearrangement of the activated complex. These data, together with our previous biochemical observation that mercurial treatment of proMMP-2/TIMP-2 exposes the MMP-2 active site without propeptide processing (Y. Itoh et al. (1995) Biochem. J. 308, 645-651), suggest that the activated proMMP-2 in the complex may represent a transitional conformational intermediate in MMP activation.

Characterization of gelatinases linked to extracellular matrix invasion in ovarian adenocarcinoma: purification of matrix metalloproteinase 2.

Substantial evidence indicates that proteolytic degradation of the extracellular matrix is necessary for invasion and metastasis by cancer cells. Our previous work has demonstrated elevated secretion by cultured ovarian adenocarcinoma cells of two gelatinolytic metalloproteinases, a 72-kDa enzyme resembling matrix metalloproteinase 2 (MMP-2) and a 92-kDa enzyme resembling MMP-9 (Moser et al, Int. J. Cancer 56, 552-559, 1994). To assess the potential in vivo relevance of these enzymes, we have examined ovarian carcinoma ascites using gelatin substrate zymography. MMP species identical to those secreted from several well-characterized ovarian adenocarcinoma cell lines were found in the majority of ascites: MMP-2-like gelatinase (23 of 23 cases) and MMP-9-like gelatinase (18 of 23 cases), suggesting a prevalence of these species in the ovarian carcinoma microenvironment and their availability for tumor-associated proteolysis. The contribution of these proteinases to ovarian cancer invasion was further demonstrated by experiments measuring tumor cell-mediated proteolysis of native endothelial cell extracellular matrix (ECM) and tumor cell invasion of reconstituted basement membrane (Matrigel). These data showed that secretion of type IV collagenase activity by a series of independently isolated ovarian adenocarcinoma cell lines correlated well with the ability of these cells to proteolyze the ECM and invade the basement membrane. Furthermore, we have identified and characterized an ovarian carcinoma-associated gelatinase, the 72-kDa MMP found in conditioned media of the DOV 13 cell line, as MMP-2. This enzyme was identical to the previously described MMP-2 from other sources by Western blot, amino terminal sequence, and substrate specificity. Additionally, a large portion of the MMP-2 activity found in DOV 13 conditioned media is active without organomercurial treatment, suggesting that ovarian cancer cells have an endogenous activator of the zymogen. Together, these data suggest that ECM proteolysis mediated by tumor-associated proteinases plays an important role in the invasion and/or metastasis of ovarian carcinoma.

A plasma membrane-associated component of ovarian adenocarcinoma cells enhances the catalytic efficiency of matrix metalloproteinase-2.

Several recent investigations have demonstrated that matrix metalloproteinase-2 (MMP-2) binds to the cell surface and undergoes zymogen activation via a plasma membrane-associated activity. The purpose of this study was to determine if association of MMP-2 with the plasma membrane also modulates the catalytic efficiency of the active enzyme. Using density gradient centrifugation, we isolated the plasma membrane fractions of two ovarian adenocarcinoma cell lines, DOV 13 and OVCA' 432, previously described either to express MMP-2 or to express no gelatinolytic metalloproteinases, respectively. While DOV 13 cells contained plasma membrane-associated MMP-2 and OVCA 432 did not, both cell types were able to bind exogenous MMP-2. Furthermore, plasma membrane fractions from these cells significantly enhanced the rate of cleavage of [14C]gelatin I substrate by both MMP-2 tissue inhibitor of metalloproteinases-2 (TIMP-2) complex (2.5-8-fold) and TIMP-2-free MMP-2 (5.9-fold). This stimulatory activity was dose-dependent, soluble in Triton X-100, and abolished by trypsin treatment of the membranes, but was stable to heat treatment. Plasma membrane stimulation of MMP-2 resulted in a 3.8-4.6-fold increase in the catalytic efficiency of gelatinolysis. These data suggest that, in addition to promoting zymogen activation, cell surface binding of MMP-2 may regulate enzyme activity by increasing the rate of substrate cleavage. Via this mechanism, tumor cell types that do not express MMPs (such as OVCA 432) nevertheless may be able to utilize exogenous MMP-2 to mediate proteolysis associated with invasion and metastasis.

Coordinate expression of urinary-type plasminogen activator and its receptor accompanies malignant transformation of the ovarian surface epithelium.

OBJECTIVE: Because elevated expression and cell surface association of urinary-type plasminogen activator have been linked to invasive potential in certain tumor types, we examined the expression of urinary-type plasminogen activator and urinary-type plasminogen activator receptor in ovarian epithelial carcinoma tissues and cells as compared with normal ovarian epithelium. STUDY DESIGN: Monoclonal antibodies specific for urinary-type plasminogen activator and urinary-type plasminogen activator receptor were used for immunohistochemical staining of tissues and cells to assess expression of these antigens in frozen sections of normal and tumor tissue. Substrate zymography was used to detect plasminogen activator activity in ovarian carcinoma ascites and in conditioned media of cultured cells, whereas a Western blot assay was used to identify urinary-type plasminogen activator receptor in cultured cells. RESULTS: Normal ovarian epithelium expressed urinary-type plasminogen activator receptor (4/4 positive) but little or no urinary-type plasminogen activator (0/4 positive), whereas epithelial ovarian carcinomas frequently expressed urinary-type plasminogen activator (4/8 positive) in conjunction with urinary-type plasminogen activator receptor (7/9 positive). High levels of urinary-type plasminogen activator were detected in 15 of 19 samples of ascites. DOV 13, OVCA 420, OVCA 429, OVCA 432, and OVCA 433 cell lines secreted urinary-type plasminogen activator in variable quantities, whereas normal ovarian epithelial cells did not secrete any detectable plasminogen activator. Urinary-type plasminogen activator receptor had similar levels of expression in all cancer cell lines and normal ovarian epithelium. CONCLUSION: Overexpression of urinary-type plasminogen activator is associated with malignant transformation of the ovarian epithelium. Increased cell surface proteolysis mediated by urinary-type plasminogen activator bound to cell surface urinary-type plasminogen activator receptor may contribute to metastatic behavior in ovarian carcinoma.

Secretion of extracellular matrix-degrading proteinases is increased in epithelial ovarian carcinoma.

The biochemical events associated with tumor invasion involve localized degradation of the basement membrane by tumor-associated proteinases. In this study, we have characterized the proteinase secretion profiles of 5 ovarian epithelial carcinoma cell lines (DOV 13, OVCA 420, OVCA 429, OVCA 432, OVCA 433) as well as normal ovarian epithelial cells. Immunocapture assays demonstrated that all 5 carcinoma cell lines produce both secreted and surface-associated plasminogen activator. Urinary-type plasminogen activator (u-PA) production was one order of magnitude greater than production of tissue-type plasminogen activator (t-PA). Furthermore, t-PA secretion by normal ovarian epithelial cells was not detectable, whereas u-PA production was 17- to 38-fold lower than in ovarian carcinoma cells. Western-blotting analysis demonstrated that u-PA was secreted as the single chain form (scu-PA) when cells were cultured in serum-free medium. Incubation of plasminogen with ovarian carcinoma cell-conditioned medium resulted in direct activation of the zymogen to plasmin. Furthermore, following incubation of cells with plasminogen, plasmin was eluted from the cell surface, indicating that ovarian carcinoma cells contain binding sites for plasminogen/plasmin which are accessible to surface-associated plasminogen activators. In addition to plasminogen activators, metalloproteinases were also produced by DOV 13, OVCA 429 and OVCA 433 cells. DOV 13 cells produce a 68-kDa metalloproteinase similar to matrix metalloproteinase 2 (MMP-2) whereas a 92-kDa enzyme similar to MMP-9 is secreted by OVCA 429 and 433. Together, ovarian carcinoma-associated plasminogen activators and metalloproteinases catalyze the hydrolysis of the major basement membrane protein components, type-IV collagen, type-IV gelatin, laminin and fibronectin. The enhanced proteolytic capability of ovarian carcinoma cells relative to normal ovarian epithelium suggests a biochemical mechanism by which invasion and spread of ovarian epithelial carcinoma may be mediated.

Ionic modulation of the effects of heparin on plasminogen activation by tissue plasminogen activator: the effects of ionic strength, divalent cations, and chloride.

Ionic strength, divalent cations, and Cl- modulate the ability of the glycosaminoglycan heparin to stimulate the activation of human plasminogen (Pg) by tissue-type Pg activator. Kinetic analysis of Pg activation indicates that heparin is inhibitory, stimulatory, or nonstimulatory as a function of ionic strength. While increasing ionic strength inhibits Pg activation in the absence of heparin, in it presence an activation phase followed by an inhibitory phase is observed. Divalent cations, inhibitors of activation in the absence of heparin, increase the rate of activation in its presence. Kinetic analysis demonstrates that divalent cations augment the heparin stimulatory effect a maximum of 60-fold due to increases in kcat without changes in Km of the reaction. This effect is heparin-specific, since activation is not affected by Ca2+ in the presence of heparan sulfate or de-N-sulfated heparin. Also, Cl- inhibits Pg activation in the presence of heparin by acting as a competitive inhibitor (Kic of 100 mM). Furthermore, inhibition by Cl- reduces the overall magnitude of heparin stimulation of Pg activation. These results suggest that physiologic ions in combination with heparin may be significant effectors of Pg activation in the vascular microenvironment.

Phosphorylation-regulated calmodulin binding to a prominent cellular substrate for protein kinase C.

We have evaluated the possibility that a major, abundant cellular substrate for protein kinase C might be a calmodulin-binding protein. We have recently labeled this protein, which migrates on sodium dodecyl sulfate-gel electrophoresis with an apparent Mr of 60,000 from chicken and 80,000-87,000 from bovine cells and tissues, the myristoylated alanine-rich C kinase substrate (MARCKS). The MARCKS proteins from both species could be cross-linked to 125I-calmodulin in a Ca2+-dependent manner. Phosphorylation of either protein by protein kinase C prevented 125I-calmodulin binding and cross-linking, suggesting that the calmodulin-binding domain might be located at or near the sites of protein kinase C phosphorylation. Both bovine and chicken MARCKS proteins contain an identical 25-amino acid domain that contains all 4 of the serine residues phosphorylated by protein kinase C in vitro. In addition, this domain is similar in sequence and structure to previously described calmodulin-binding domains. A synthetic peptide corresponding to this domain inhibited calmodulin binding to the MARCKS protein and also could be cross-linked to 125I-calmodulin in a calcium-dependent manner. In addition, protein kinase C-dependent phosphorylation of the synthetic peptide inhibited its binding and cross-linking to 125I-calmodulin. The peptide bound to fluorescently labeled 5-dimethylaminonaphthalene-1-sulfonyl-calmodulin with a dissociation constant of 2.8 nM, and inhibited the calmodulin-dependent activation of cyclic nucleotide phosphodiesterase with an IC50 of 4.8 nM. Thus, the peptide mimics the calmodulin-binding properties of the MARCKS protein and probably represents its calmodulin-binding domain. Phosphorylation of these abundant, high affinity calmodulin-binding proteins by protein kinase C in intact cells could cause displacement of bound calmodulin, perhaps leading to activation of Ca2+-calmodulin-dependent processes.