Cluster-analysis & patterns of dissemination of multidrug resistance among clinical strains of Vibrio cholerae in Calcutta, India

BACKGROUND & OBJECTIVES

Antimicrobial resistance among Vibrio cholerae has been monitored for several years in Calcutta. To investigate the changing trends in multidrug resistance (MDR) among different serogroups of V. cholerae and to perform software assisted cluster analysis the current study was undertaken.

METHODS

Strains isolated from patients with cholera and "cholera-like" diarrhoea admitted in the Infectious Diseases Hospital, Calcutta were analysed. Eight hundred and forty V. cholerae strains isolated from 1992 through 1997 were tested for susceptibility to 11 antibiotics. Cluster analysis was done using SPSS software.

RESULTS

Most of the strains exhibited MDR with fluctuating trends as the resistance profile diverged each year. A total of 119 different resistance profiles exhibited by V. cholerae O1, O139 and non-O1, non-O139 serogroups were analysed by cluster combination method. During 1993 and 1994, 53 per cent of V. cholerae O139 and 82 per cent of V. cholerae O1 serogroups, respectively, exhibited maximal number of new resistance patterns. The frequency of new resistance patterns among V. cholerae non-O1, non-O139 was constantly high (33-47%) during 1995 to 1997.

INTERPRETATION & CONCLUSIONS

With a few exceptions, preponderance of the resistance profiles was generally not confined to any serogroup. The cluster analysis depicted dissemination of some of the resistance patterns commonly found among V. cholerae non-O1, non-O139 belonging to different serogroups to the O139 serogroup in the succeeding years. In this study we have shown that the V. cholerae strains are resistant to several antibiotics with constant change in the MDR profiles. It is imperative to define the susceptibility pattern of the strains to determine the effective drug of choice for the treatment of cholera.

Developmental toxicity of valproic acid during embryonic chick vertebral chondrogenesis

STUDY DESIGN

Valproic acid (2-n-propylpentanoic acid, VPA), an anticonvulsant drug, was studied for its effects on cartilage matrix gene expression using dot blot hybridization with cDNA probes during early chondrogenesis in the developing lumbar spine.

OBJECTIVES

To determine the noncytotoxic effects of VPA on vertebral chondrocytes at various stages of embryonic chick spine development.

SUMMARY OF BACKGROUND DATA

Clinical and epidemiologic studies have indicated that maternal use of valproic acid during early pregnancy causes an increased risk for spina bifida.

METHODS

The sequence of chondrogenesis in the chick lumbar region was determined for stages HH23-32 and stage-correlated with matrix gene expression by dot blot hybridization analysis using cDNA probes for type II collagen, type IX collagen, and cartilage-specific aggrecan core protein.

RESULTS

The mesenchymal stage of lumbar chondrogenesis in the chick spine occurs from HH23-26, the prechondrogenic stage between HH27-28, and the chondrogenic period from HH29-32. Stabilization of the cartilage phenotype in the lumbar region is evident at HH-29. Type IX collagen and aggrecan core protein mRNA levels were significantly reduced (P < 0.01) after 48 hours of incubation of the lumbar spines from HH29-31 in the presence of 200 microg/mL and 300 microg/mL valproic acid. Lumbar spines cultured for an additional 24 hours after removal of valproic acid showed only an isolated instance of escape from the inhibitory action of 200 microg/mL valproic acid for type IX collagen at HH31.

CONCLUSIONS

Valproic acid significantly alters cartilage matrix gene expression during embryonic lumbar vertebral chondrogenesis. The alteration in gene expression for critical matrix proteins during vertebral chondrogenesis may be related to mechanisms underlying the failure of neural arch development in lumbar spina bifida.

Effect of glucagon-like peptide 1(7-36) amide on glucose effectiveness and insulin action in people with type 2 diabetes

Although it is well established that glucagon-like peptide 1(7-36) amide (GLP-1) is a potent stimulator of insulin secretion, its effects on insulin action and glucose effectiveness are less clear. To determine whether GLP-1 increases insulin action and glucose effectiveness, subjects with type 2 diabetes were studied on two occasions. Insulin was infused during the night on both occasions to ensure that baseline glucose concentrations were comparable. On the morning of study, either GLP-1 (1.2 pmol x kg(-1) x min(-1)) or saline were infused along with somatostatin and replacement amounts of glucagon. Glucose also was infused in a pattern mimicking that typically observed after a carbohydrate meal. Insulin concentrations were either kept constant at basal levels (n = 6) or varied so as to create a prandial insulin profile (n = 6). The increase in glucose concentration was virtually identical on the GLP-1 and saline study days during both the basal (1.21 +/- 0.15 vs. 1.32 +/- 0.19 mol/l per 6 h) and prandial (0.56 +/- 0.14 vs. 0.56 +/- 0.10 mol/l per 6 h) insulin infusions. During both the basal and prandial insulin infusions, glucose disappearance promptly increased after initiation of the glucose infusion to rates that did not differ on the GLP-1 and saline study days. Suppression of endogenous glucose production also was comparable on the GLP-1 and saline study days during both the basal (-2.7 +/- 0.3 vs. -3.1 +/- 0.2 micromol/kg) and prandial (-3.1 +/- 0.4 vs. -3.0 +/- 0.6 pmol/kg) insulin infusions. We conclude that when insulin and glucagon concentrations are matched, GLP-1 has negligible effects on either insulin action or glucose effectiveness in people with type 2 diabetes. These data strongly support the concept that GLP-1 improves glycemic control in people with type 2 diabetes by increasing insulin secretion, by inhibiting glucagon secretion, and by delaying gastric emptying rather than by altering extrapancreatic glucose metabolism.

The genome sequence of Drosophila melanogaster

The fly Drosophila melanogaster is one of the most intensively studied organisms in biology and serves as a model system for the investigation of many developmental and cellular processes common to higher eukaryotes, including humans. We have determined the nucleotide sequence of nearly all of the approximately 120-megabase euchromatic portion of the Drosophila genome using a whole-genome shotgun sequencing strategy supported by extensive clone-based sequence and a high-quality bacterial artificial chromosome physical map. Efforts are under way to close the remaining gaps; however, the sequence is of sufficient accuracy and contiguity to be declared substantially complete and to support an initial analysis of genome structure and preliminary gene annotation and interpretation. The genome encodes approximately 13,600 genes, somewhat fewer than the smaller Caenorhabditis elegans genome, but with comparable functional diversity.

Regulation of Bcl2 phosphorylation by stress response kinase pathway

The anticancer drugs affecting either microtubule polymerization or depolymerization could trigger Bcl2 phosphorylation in mitotic phase of the cell cycle. By systematic site directed mutagenesis studies, we have previously mapped taxol induced phosphorylation sites to be Ser-70 and 87 residues of Bcl2 protein. Interestingly, sequences surrounding both serine-70 and serine-87 residues represent MAP kinase consensus motif. Since Bcl2 phosphorylation predominantly occurs at site consensus to MAP kinase family members, we were interested to test whether Erk2 or Jun kinase is involved in this pathway. Our in vitro studies document that stress activated kinase, JNK1 is responsible for Bcl2 phosphorylation.

Coupled nonequilibrium growth equations: self-consistent mode coupling using vertex renormalization

We find that studying the simplest of the coupled nonequilibrium growth equations of Barabasi by self-consistent mode coupling requires the use of dressed vertices. Using the vertex renormalization, we find a roughening exponent which already in the leading order is quite close to the numerical value.

One step enzyme linked immunosorbent assay for direct estimation of serum cortisol

One step competitive enzyme linked immunosorbent assay (ELISA) for direct estimation of cortisol in human serum is described. Cortisol-3-O-carboxymethyl-oxime-bovine serum albumin (cortisol-3-O-CMO-BSA) was used as an immunogen and cortisol-21-hemisuccinate-horse radish peroxidase (cortisol-21-HS-HRP) was used as a tracer. To the cortisol antibody coated microtiter wells, standards or serum samples (25 microl) along with cortisol-HRP conjugate (100 microl) were incubated for 2 hours at 37 degrees C. Bound enzyme activity was measured by, using TMB/H2O2 as a substrate. In this new strategy, chilled acetone stripped pooled human serum and sodium salicylate were used for preparing the standards and blocking the cortisol binding globulin (CBG), respectively. The sensitivity of the assay was .28 microg/100ml. The intraassay and interassay coefficient of variations (CVs) were ranged from 1.3% to 9.3% and 6.8% to 12.3 %, respectively. The analytical recoveries were 94% to 101.5%. The serum cortisol values, obtained by this method were correlated well with those, obtained by radioimmunoassay; r=0.95 (n=52).

Decaying magnetohydrodynamics: effects of initial conditions

We study the effects of homogenous and isotropic initial conditions on decaying magnetohydrodynamics (MHD). We show that for an initial distribution of velocity and magnetic-field fluctuations, appropriately defined structure functions decay as a power law in time. We also show that for a suitable choice of initial cross correlations between velocity and magnetic fields even-order structure functions acquire anomalous scaling in time where as scaling exponents of the odd-order structure functions remain unchanged. We discuss our results in the context of fully developed MHD turbulence.

Modulation of CD11C+ splenic dendritic cell functions in murine visceral leishmaniasis: correlation with parasite replication in the spleen

BALB/c mice resolve Leishmania donovani infection in the liver over an 8-12-week period. However, after an initial phase of 2-4 weeks where increases in parasite load are not readily detectable, parasite numbers in the spleen begin to increase reaching maximum levels at 16 weeks post-infection. Thereafter, parasite replication in the spleen is controlled and BALB/c mice maintain this residual parasite load in the spleen for many months, without further increase. We evaluated functions of CD11C+ splenic dendritic cells throughout the course of L. donovani infection in the spleen of BALB/c mice. Unlike the dendritic cell (DC)-specific antigen DEC-205, CD11C was not up-regulated on macrophages during visceral leishmaniasis. No appreciable impairment of splenic DC functions was observed when this antigen-presenting cell subset was purified from 30-day post-infected mice. Significant impairment in inducing allogeneic mixed lymphocyte reaction (MLR) and presenting L. donovani antigens or keyhole limpet haemocyanin (KLH) to specific T cells was observed with CD11C+ splenic DC purified from 60-day post-infected mice. Functional impairment of splenic DC at 60 days post-infection correlated with their reduced surface expression of major histocompatibility complex (MHC) class II molecules, impairment of interleukin-12 (IL-12) production and to their ability to suppress interferon-gamma (IFN-gamma) production by Leishmania antigen-primed T cells. Of interest, the impairment of splenic DC in presenting Leishmania antigens or KLH to specific T cells was corrected at 120 days post-infection, and correlated with their up-regulation of MHC class II expression, IL-12 production, induction of IFN-gamma by Leishmania antigen-primed T cells and the onset of control over splenic parasite replication in vivo. These results indicate that functional integrity of DC may be important in controlling L. donovani infection.

Effects of type 2 diabetes on the ability of insulin and glucose to regulate splanchnic and muscle glucose metabolism: evidence for a defect in hepatic glucokinase activity

Insulin-induced stimulation of muscle glucose uptake (MGU) is impaired in people with type 2 diabetes. To determine whether insulin-induced stimulation of splanchnic glucose uptake (SGU) is also impaired, we simultaneously measured leg glucose uptake (LGU) and SGU in 14 nondiabetic subjects and 16 subjects with type 2 diabetes using a combined organ catheterization-tracer infusion technique. Glucose was clamped at approximately 9.3 mmol/l, while insulin concentrations were maintained at approximately 72 pmol/l (low) and approximately 150 pmol/l (high) for 3 h each. Endogenous hormone secretion was inhibited with somatostatin. Total body glucose disappearance was lower (P < 0.01) and glucose production higher (P < 0.01) during both insulin infusions in the diabetic compared with the nondiabetic subjects, indicating insulin resistance. Splanchnic glucose production was higher (P < 0.05) in the diabetic subjects during the low but not the high insulin infusion. SGU was slightly lower in the diabetic than in the nondiabetic subjects during the low insulin infusion and 50-60% lower (P < 0.05) during the high insulin infusion. LGU (P < 0.001), but not SGU, was inversely correlated with the degree of visceral adiposity. The contribution of the indirect pathway to hepatic glycogen synthesis did not differ in the diabetic and nondiabetic subjects. In contrast, both flux through the UDP-glucose pool (P < 0.05) and the contribution of the direct pathway to glycogen synthesis (P < 0.01) were lower in the diabetic than in the nondiabetic subjects, indicating decreased uptake and/or phosphorylation of extracellular glucose. On the other hand, glycogenolysis was equally suppressed in both groups. In summary, type 2 diabetes impairs the ability of insulin to stimulate both MGU and SGU. The defect appears to reside at a proximal (e.g., glucokinase) metabolic step and is not related to the degree of visceral adiposity. These data suggest that impaired hepatic glucose uptake as well as MGU contribute to hyperglycemia in people with type 2 diabetes.

Inequivalence of dynamical ensembles in a generalized driven diffusive lattice gas

We generalize the driven diffusive lattice gas model by using a combination of Kawasaki and Glauber dynamics. We find via Monte Carlo simulations and perturbation studies that the simplest possible generalization of the equivalence of the canonical and grand-canonical ensembles, which holds in equilibrium, does not apply for this class of nonequilibrium systems.

Diversity in the arrangement of the CTX prophages in classical strains of Vibrio cholerae O1

This study reports the results of a molecular analysis of the CTX prophages in classical biotype strains of Vibrio cholerae O1 of clinical origin isolated between 1970 and 1979 in India. All strains were sensitive to group IV classical phage and polymyxin B but resistant to group 5 El Tor phage. These phenotypic traits are consistent to that exhibited by the classical biotype. PCR studies reconfirmed their biotype assignment and showed the presence of intact CTX prophages and the presence of the recently described toxin linked cryptic plasmid. Restriction fragment length polymorphism of rRNA genes and pulsed-field gel electrophoresis showed clonal diversity among the strains. The most notable observation was the finding that one strain (GP13) has three CTX prophages while another (GP147) has four CTX prophages. This is the first time heterogeneity is reported in the arrangement of the CTX prophages among classical strains of V. cholerae O1.

Vibrio cholerae O139 in Calcutta, 1992-1998: incidence, antibiograms, and genotypes

We report results of surveillance for cholera caused by Vibrio cholerae O139 from September 1992, when it was first identified, to December 1998. V. cholerae O139 dominated as the causative agent of cholera in Calcutta during 1992-93 and 1996- 97, while the O1 strains dominated during the rest of the period. Dramatic shifts in patterns of resistance to cotrimoxazole, neomycin, and streptomycin were observed. Molecular epidemiologic studies showed clonal diversity among the O139 strains and continuous emergence of new epidemic clones, reflected by changes in the structure, organization, and location of the CTX prophages in the V. cholerae O139

Loss of insulin-like growth factor I receptor-dependent expression of p107 and cyclin A in cells that lack the extracellular matrix protein secreted protein acidic and rich in cysteine

The extracellular matrix-associated glycoprotein secreted protein acidic and rich in cysteine (SPARC) has been implicated in the control of cell proliferation during tissue remodeling, wound healing, and malignant development. Here, we describe a novel mechanism through which SPARC influences cell cycle progression in embryonic fibroblasts derived from Sparc-nullizygous (-/-) mice. SPARC-deficient cells were indistinguishable from wild-type cells in their ability to initiate DNA synthesis after treatment with either fetal bovine serum or platelet-derived growth factor. In contrast, Sparc -/- cells responded poorly to activation of the insulin-like growth factor receptor (IGFI-R) by insulin. This defect was traced to reduced expression of the IGFI-R in Sparc -/- cells. Consistent with impaired cell cycle progression through S-phase, insulin-stimulated Sparc -/- cells also revealed reduced expression of two key regulators of S phase progression (cyclin A and thymidine kinase), whereas expression of the G1 phase progression regulators cmyc or cyclin D1 was unaffected. An examination of the status of retinoblastoma family pocket proteins in Sparc -/- cells revealed a selective and dramatic reduction in levels of the retinoblastoma-related protein p107. Exogenous platelet-derived growth factor restored expression of the IGFI-R and IGFI-R dependent DNA synthesis as well as induction of cyclin A, thymidine kinase, and p107 in insulin-stimulated Sparc -/- cells. These results suggest that SPARC-dependent matrix to cell interactions contribute to the regulation of p107 and cyclin A through IGFI-R dependent pathway(s).

Reversible S-nitrosation and inhibition of HIV-1 protease

Nitric oxide (*NO) is a short-lived free radical with many functions including vasoregulation, synaptic plasticity, and immune modulation and has recently been associated with AIDS pathology. Various pathophysiological conditions, such as viral infection, trigger inducible nitric oxide synthase (iNOS) to synthesize NO in the cell. NO-derived species can react with thiols of proteins and form nitrosothiol adducts. HIV-1 protease (HIV-PR) contains two cysteine residues, Cys67 and Cys95, which are believed to serve a regulatory function. We have found that HIV-PR is inactivated by nitric oxide produced in vitro by NO donors and by iNOS. Sodium nitroprusside inhibited HIV-PR by 70%, and S-nitroso-N-acetylpenicillamine completely inhibited the enzyme. Furthermore, iNOS generated sufficient NO to inhibit HIV-PR activity by almost 90%. This inactivation was reversed by the addition of reducing agents. Treatment of HIV-PR with NO donors and ritonavir (a competitive peptide inhibitor) indicates that NO exerts its effect through a site independent of the active site of HIV-PR. Using electrospray ionization mass spectrometry, we found that NO forms S-nitrosothiols on Cys67 and Cys95 of HIV-PR which directly correlate with a loss of activity. These data indicate that NO may suppress HIV-1 replication by directly inhibiting HIV-PR.

Potent antitumor agent proteasome inhibitors: a novel trigger for Bcl2 phosphorylation to induce apoptosis

The sustained cytotoxicity conferred by proteasome inhibitors against a broad spectrum of human cancer cells is mediated by a delicate mechanism of programmed cell death. Similar to microtubule disarraying agents, the cell death induced by these potent antitumor agents precedes blocking in cell cycle transition at G2-M phase. The microtubule damaging antineoplastic drugs can kill tumor cells by inducing phosphorylation of antiapoptotic proteins such as Bcl2, Bcl-xL or MCL-1. The simultaneous apoptosis with Bcl2 phosphorylation was evident in cancer cells challenged with the proteasome inhibitor, MG132. Our studies suggest that the proteasome inhibitor MG132 induced tumor cell killing is mediated through Bcl2 phosphorylation.

Effect of transradial access on quality of life and cost of cardiac catheterization: A randomized comparison

BACKGROUND

Transradial access is a recently developed alternative for diagnostic cardiac catheterization. Its effects on quality of life after the procedure, patient preference, and cost are unknown.

METHODS AND RESULTS

We performed a randomized single-center trial in which 99 patients underwent transfemoral and 101 underwent transradial diagnostic cardiac catheterization. Quality of life was measured with the SF-36 and visual analog scales at baseline, 1 day, and 1 week. Patients were examined at 1 day and at 1 week after for complications. Costs were measured prospectively. One patient in the femoral group and 2 in the radial group crossed over to the alternative access site. There were no major access site complications. One patient in the transfemoral group had a minor stroke. Transradial catheterization significantly reduced median length of stay (3.6 vs 10.4 hours, P <.0001). Over the first day after the procedure, measures of bodily pain, back pain, and walking ability favored the transradial group (P <.05 for all comparisons). Over the week after the procedure, changes in role limitations caused by physical health, bodily pain, and back pain favored the transradial group (P <.05 for all comparisons). There was a strong patient preference for transradial catheterization as well (P <. 0001). Transradial catheterization led to significant reductions in bed, pharmacy, and total hospital costs ($2010 vs $2299, P <.0001).

CONCLUSIONS

Among patients undergoing diagnostic cardiac catheterization, transradial access leads to improved quality of life after the procedure, is strongly preferred by patients, and reduces hospital costs.

ZPK inhibits PKA induced transcriptional activation by CREB and blocks retinoic acid induced neuronal differentiation

Zipper Protein Kinase (ZPK) is a leucine zipper protein localized to the nucleus which exhibits serine-threonine kinase activity and is associated with the stress dependent signal transduction pathway. ZPK forms heterodimers with leucine zipper containing transcription factors such as the cyclic AMP responsive element binding protein (CREB) and Myc. Furthermore ZPK phosphorylates both Myc and CREB. Overexpression of ZPK in NTera-2 human teratocarcinoma cells results in inhibition of PKA induced transcriptional activation by CREB and prevents retinoic acid induced differentiation of the cells to neurons. Our results suggest that ZPK stifles neural differentiation of NT-2 cells partly due to its inhibitory effect on CREB function.

Impact of lack of suppression of glucagon on glucose tolerance in humans

People with type 2 diabetes have defects in both alpha- and beta-cell function. To determine whether lack of suppression of glucagon causes hyperglycemia when insulin secretion is impaired but not when insulin secretion is intact, twenty nondiabetic subjects were studied on two occasions. On both occasions, a "prandial" glucose infusion was given over 5 h while endogenous hormone secretion was inhibited. Insulin was infused so as to mimic either a nondiabetic (n = 10) or diabetic (n = 10) postprandial profile. Glucagon was infused at a rate of 1.25 ng. kg(-1). min(-1), beginning either at time zero to prevent a fall in glucagon (nonsuppressed study day) or at 2 h to create a transient fall in glucagon (suppressed study day). During the "diabetic" insulin profile, lack of glucagon suppression resulted in a marked increase (P < 0.002) in both the peak glucose concentration (11.9 +/- 0.4 vs. 8.9 +/- 0.4 mmol/l) and the area above basal of glucose (927 +/- 77 vs. 546 +/- 112 mmol. l(-1). 6 h) because of impaired (P < 0.001) suppression of glucose production. In contrast, during the "nondiabetic" insulin profile, lack of suppression of glucagon resulted in only a slight increase (P < 0.02) in the peak glucose concentration (9.1 +/- 0.4 vs. 8.4 +/- 0.3 mmol/l) and the area above basal of glucose (654 +/- 146 vs. 488 +/- 118 mmol. l(-1). 6 h). Of interest, when glucagon was suppressed, glucose concentrations differed only minimally during the nondiabetic and diabetic insulin profiles. These data indicate that lack of suppression of glucagon can cause substantial hyperglycemia when insulin availability is limited, therefore implying that inhibitors of glucagon secretion and/or glucagon action are likely to be useful therapeutic agents in such individuals.

Effect of overnight restoration of euglycemia on glucose effectiveness in type 2 diabetes mellitus

The ability of glucose to stimulate its own uptake and suppress its own release is impaired in type 2 diabetes. To determine whether glucose effectiveness is improved by short term euglycemia, 10 type 2 diabetic subjects were studied on 2 occasions. Insulin was infused throughout the night to maintain euglycemia (approximately 5 mmol/L), or glucose was permitted to remain at ambient hyperglycemic levels (approximately 10 mmol/L) until the following morning when euglycemia was achieved with a variable insulin infusion. A prandial glucose infusion (containing 35 g glucose) was started at 1000 h, and the variable insulin infusion was replaced by a constant infusion of insulin (0.25 mU/ kg x min), somatostatin (60 ng/kg x min), glucagon (0.65 ng/kg x min), and GH (3 ng/kg x min) to maintain hormone concentrations at constant basal levels. Although nocturnal glucose concentrations were (by design) higher (P<0.01) on the hyperglycemic than on the euglycemic study day (10.1+/-0.2 vs. 5.4+/-0.1 mmol/L), glucose concentrations did not differ either before (4.9+/-0.1 vs. 4.9+/-0.1 mmol/L) or during the prandial glucose infusion (peak, 11.1+/-0.5 vs. 11.3+/-0.5 mmol/L; incremental area, 1390+/-254 vs. 1409+/-196 mmol/L x 6 h). Furthermore, glucose-induced stimulation of glucose disappearance (2068+/-218 vs. 1957+/-244 micromol/kg x 6 h) and suppression of glucose production (-2253+/-378 vs. -2124+/-257 micromol/kg x 6 h) did not differ. Thus, restoration of euglycemia by means of an overnight insulin infusion does not alter glucose effectiveness in people with type 2 diabetes.

Bin1 functionally interacts with Myc and inhibits cell proliferation via multiple mechanisms

The tumor suppressor Bin1 was identified through its interaction with the N-terminal region of Myc which harbors its transcriptional activation domain. Here we show that Bin1 and Myc physically and functionally associate in cells and that Bin1 inhibits cell proliferation through both Myc-dependent and Myc-independent mechanisms. Bin1 specifically inhibited transactivation by Myc as assayed from artificial promoters or from the Myc target genes ornithine decarboxylase (ODC) and alpha prothymosin (pT). Inhibition of ODC but not pT required the presence of the Myc binding domain (MBD) of Bin1 suggesting two mechanisms of action. Consistent with this possibility, a non-MBD region of Bin1 was sufficient to recruit a repression function to DNA that was unrelated to histone deacetylase. Regions outside the MBD required for growth inhibition were mapped in Ras cotransformation or HepG2 hepatoma cell growth assays. Bin1 required the N-terminal BAR domain to suppress focus formation by Myc whereas the C-terminal U1 and SH3 domains were required to inhibit adenovirus E1A or mutant p53, respectively. All three domains contributed to Bin1 suppression of tumor cell growth but BAR-C was most crucial. These findings supported functional interaction between Myc and Bin1 in cells and indicated that Bin1 could inhibit malignant cell growth through multiple mechanisms.

Regulation of caspase activation and cis-diamminedichloroplatinum(II)-induced cell death by protein kinase C

Activation of caspases is critical for the induction of apoptosis. We have shown previously that cell death mediated by the anticancer agent cis-diamminedichloroplatinum(II) (cDDP) is influenced by the protein kinase C (PKC) signal transduction pathway. In the present study, we have examined whether regulation of cDDP sensitivity by PKC involves caspase activation. cDDP caused a time- and concentration-dependent increase in the generation of the catalytic fragment (CF) of novel (n) PKCdelta, nPKCepsilon, and atypical (a) PKCzeta but had little effect on conventional (c) PKCalpha. Cleavage of PKC isozymes was associated with the activation of caspase-3 and -7 but not of caspase-2. PKC activators enhanced cDDP-induced cleavage of these isozymes and activation of caspase-3. Rottlerin, an inhibitor of nPKCdelta, blocked caspase-3 activation and proteolytic cleavage of nPKCdelta by cDDP. Bryostatin 1, which elicits a biphasic concentration-response in potentiating cell death by cDDP, exhibited a similar biphasic effect on cDDP-induced activation of caspase-3 and caspase-7 and the cleavage of poly(ADP-ribose) polymerase; while 1 nM bryostatin 1 induced maximum activation of these caspases, 1 microM bryostatin 1 had little effect. z-DEVD-fmk, an inhibitor of caspase-3-like proteases, prevented cDDP-induced cell death. Bryostatin 1 also induced a similar biphasic down-regulation of nPKCdelta but not of cPKCalpha or nPKCepsilon. These results suggest that nPKCdelta not only acts downstream of caspases but also regulates the activation of caspases and that the biphasic concentration response of bryostatin 1 on cDDP-induced cell death could be explained by its distinct effect on nPKCdelta down-regulation and caspase activation.

Indolylquinoline derivatives are cytotoxic to Leishmania donovani promastigotes and amastigotes in vitro and are effective in treating murine visceral leishmaniasis

A wide variety of biologically active compounds contain indole and quinoline nuclei. Some novel indolylquinoline derivatives were synthesized from indole by Friedel-Crafts acylation reaction. Out of the four derivatives tested, 2-(2''-acetamidobenzyl)-3-(3'-indolylquinoline) (C) had no effect on the promastigotes or amastigotes of Leishmania donovani in vitro. The remaining three analogues, 2-(2''-dichloroacetamidobenzyl)-3-(3'-indolylquinoline) (A), 2-(2''-chloroacetamidobenzyl)-3-(3'-indolylquinoline) (B), and 2-(2''-aminobenzyl)-3-(3'-indolylquinoline) (D), inhibited the growth of L. donovani promastigotes in vitro and were cytotoxic to both the promastigote and amastigote forms of the parasite. These three derivatives were also effective in eliminating L. donovani amastigotes from BALB/c mouse peritoneal macrophages in vitro. One indolylquinoline derivative [A] was used to treat established visceral leishmaniasis in BALB/c mice. This compound was significantly more effective than sodium antimony gluconate (SAG) in reducing the splenic parasite load at a much lower concentration (5% of SAG). Our results suggest that indolylquinoline derivatives may be exploited as antileishmanial agents.