Self-Assembly of Copper Oxide Interfaced MnO2 for Oxygen Evolution Reaction

Designing efficient electrocatalytic systems through facile synthesis remains a formidable task. To address this issue, this paper presents the design of a combination material comprising two transition metal oxides (copper oxide and manganese oxide (CuO/MnO2)), synthesized using a conventional microwave technique to efficiently engage as an active oxygen evolution reaction (OER) catalyst. The structural and morphological properties of the composite were confirmed by the aid of X-ray diffraction (XRD) studies, field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and energy-dispersive spectrometry (EDS). FESEM clearly indicated well-aligned interlacing of CuO with MnO2. The OER performance was carried out in 1 M KOH. The assembled CuO/MnO2 delivered a benchmark current density (j = 10 mA cm-2) at a minimal overpotential (η = 294 mV), while pristine CuO required a high η (316 mV). Additionally, the CuO/MnO2 electrocatalyst exhibited stability for more than 15 h. These enhanced electrochemical performances were attributed to the large volume and expanded diameter of the pores, which offer ample surface area for catalytic reactions to boost OER. Furthermore, the rate kinetics of the OER are favored in composite due to low Tafel slope (77 mV/dec) compared to CuO (80 mV/dec).

Nanostructurally engineered TiO2 embedded Mentha aquatica biowaste derived carbon for supercapacitor applications

The invention of cost-effective, clean, and eco-friendly energy storage technology has been capturing a lot of worldwide interest. Herein, biogenically synthesized TiO₂ nanoparticles (NPs) were ultrasonically coupled with biomass-derived activated carbon (BAC) to obtain composite (denoted as TiO₂@BAC). With the inspiration of nature, Mentha Aquatica leaves extract was employed for biogenic preparation of TiO₂ NPs, and residual solid waste (SW) after extract was subsequently utilized for BAC. It is noteworthy that, this unique intensive method does not require any harmful or toxic chemicals and solvents, and no secondary waste is generated. TEM analysis of TiO₂@BAC revealed spherical morphology of TiO₂ NPs (average size ∼ 18 nm) that were accumulated on nanosheets. Raman, XRD, and XPS manifested the successful construction of TiO₂@BAC. The electrochemical performance of the as-synthesized BAC, TiO₂ NPs, and TiO₂@BAC electrodes was tested towards supercapacitor applications. Notably, the TiO₂@BAC electrode exhibited capacitance of 149 F/g at a current density of 1 A/g, which is approximately twice than that of the bare TiO₂ electrode (76 F/g) along with excellent capacitance restoration of ∼99%. The TiO₂@BAC electrode further revealed outstanding cyclic stability, exhibiting capacitance retention of ∼90% (at 5 A/g) after 10,000 charge/discharge cycles. Furthermore, the TiO₂@BAC electrode delivered optimal specific energy density (6.96 Wh/kg) and large power density (2.07 kW/kg at 10 A/g). Moreover, the TiO₂@BAC delivers an excellent restoration and retention performances of ∼100 and ∼95% (after 10,000 cycles) at 1 A/g with ∼98% coulombic efficiency in symmetric configuration (maximum cell voltage of 1.2 V).

New peptide derived antimalaria and antimicrobial agents bearing sulphonamide moiety

Fourteen novel dipeptide carboxamide derivatives bearing benzensulphonamoyl propanamide were synthesized and characterized using 1H NMR, 13C NMR, FTIR and MS spectroscopic techniques. In vivo antimalarial and in vitro antimicrobial studies were carried out on these synthesized compounds. Molecular docking, haematological analysis, liver and kidney function tests were also evaluated to assess the effect of the compounds on the organs. At 200 mg/kg body weight, 7i inhibited the multiplication of the parasite by 81.38% on day 12 of post-treatment exposure. This was comparable to the 82.34% reduction with artemisinin. The minimum inhibitory concentration (MIC) in µM ranged from 0.03 to 2.34 with 7h having MIC of 0.03 µM against Plasmodium falciparium. The in vitro antibacterial activity of the compounds against some clinically isolated bacteria strains showed varied activities with some of the new compounds showing better activities against the bacteria and the fungi more than the reference drug ciprofloxacin and fluconazole.

Cognitive Dysfunction and Associated Behaviour Problems in Postpartum Women: A Study from North India

OBJECTIVES

During and after childbirth women undergo tremendous psychological and biological changes. These biological changes, along with the stress of assuming the new role of mother, make postpartum women vulnerable to various psychiatric disorders including cognitive dysfunction, depression, and anxiety. Such problems are under-reported as they are difficult to identify, especially by caregivers who are more focused on the newborn. The present study aimed to evaluate the prevalence of behaviour problems and cognitive dysfunction during the postpartum period.

METHODS

A cross-sectional study was carried out at the Department of Obstetrics and Gynaecology, Jawahar Lal Nehru Medical College, Ajmer, India. The study sample included 200 consecutive women who came for their first follow-up after childbirth, and 100 healthy and non-pregnant women who served as controls. Cognitive function was assessed using the Standard Mini-Mental State Examination Scale (SMMSE), Brief Cognitive Rating Scale (BCRS), and Trail Making Test Part B (TMT-B). 21-Item Depression Anxiety and Stress Scale was administered to assess depressive and anxiety symptoms.

RESULTS

Postpartum women scored poorly on SMMSE, BCRS, and TMT-B compared with non-pregnant women (p < 0.001), whereas subscores of depression, anxiety, and stress were significantly higher (p < 0.001).

CONCLUSIONS

Women had significantly more cognitive deficits during the postpartum period than their non-pregnant counterparts. The former also had a higher prevalence of depression, anxiety, and stress.

Diabetes, hypertension, sanitation, and health education by high school students in Guyana, South America

We initiated a program for early detection of diabetes and hypertension, the main causes of kidney failure in Guyana, South America. We trained local high school students with the goal that these students would stay in the villages for long-term, become health advocates and shift the reliance away from physicians. This project involved 7 high school students who were taught to monitor the health of one village of 1000–1500 population each. The program will be implemented for 3 years in which the entire population of seven villages (approximately 10,000 people) will be covered. This represents 1.3% population in Guyana. We present data from the pilot study from the sample of 619 people. The prevalence of diabetes mellitus was 13.9%. Among diabetics, 33.7% were using insulin and 86% oral hypoglycemic agents. Prevalence of hypertension was 29.4%, 63.2% were overweight and 17% were obese. About 9.9% patients were unaware about the existence of hypertension. We have shown in our study that high school students can be used to collect health data and monitor diabetes and hypertension. There was also a significant incidence of undetected diabetes and hypertension.

A double barrier memristive device

We present a quantum mechanical memristive Nb/Al/Al2O3/NbxOy/Au device which consists of an ultra-thin memristive layer (NbxOy) sandwiched between an Al2O3 tunnel barrier and a Schottky-like contact. A highly uniform current distribution for the LRS (low resistance state) and HRS (high resistance state) for areas ranging between 70 μm2 and 2300 μm2 were obtained, which indicates a non-filamentary based resistive switching mechanism. In a detailed experimental and theoretical analysis we show evidence that resistive switching originates from oxygen diffusion and modifications of the local electronic interface states within the NbxOy layer, which influences the interface properties of the Au (Schottky) contact and of the Al2O3 tunneling barrier, respectively. The presented device might offer several benefits like an intrinsic current compliance, improved retention and no need for an electric forming procedure, which is especially attractive for possible applications in highly dense random access memories or neuromorphic mixed signal circuits.

The effectiveness of mood stabilizers and antiepileptic medication for the management of behaviour problems in adults with intellectual disability: a systematic review

BACKGROUND

Psychotropic medications are used to manage behaviour problems in adults with intellectual disability (ID). One group of psychotropic medication are mood stabilizers such as lithium and some antiepileptic drugs.

METHOD

A comprehensive systematic review was performed to determine the evidence base for the effectiveness of mood stabilizers in the management of behaviour problems among adults with ID. Electronic searches of PsycInfo, Medline, Embase and Cinahl databases were conducted, as well as a thorough hand search for relevant literature. We reviewed primary trials relating to adults only that satisfied strict inclusion criteria.

RESULTS

One randomized controlled trial (RCT) relating to lithium use and two non-RCTs, one on lithium and the other on carbamazepine, were revealed. In addition, one prospective non-controlled trial on sodium valproate and three retrospective case series studies were discovered, of which one considered the efficacy of lithium, one valproate and one topiramate.

CONCLUSIONS

The current evidence lends some support for the use of lithium and some antiepileptic mood stabilizer medication for the management of behaviour problems in adults with ID. However, because most studies reviewed here are riddled with obvious methodological constrains, the findings have to be interpreted with caution.

Gene expression profile of ovalbumin-induced lung inflammation in a murine model of asthma

BACKGROUND

Asthma is a chronic inflammatory disease that is associated with airway hyperresponsiveness, tissue remodeling, and airway obstruction, and that involves coordinate expression of multiple inflammatory genes in the lungs.

OBJECTIVE

To evaluate the gene expression pattern in a mouse model of asthma and assess the effect of a new drug, R142571, on the gene expression profile.

METHODS

Lung tissue from ovalbumin-sensitized mice was used to examine gene expression on the CodeLink oligonucleotide mouse 20 K bioarray platform. Data were validated for some genes by semiquantitative reverse-transcriptase polymerase chain reaction.

RESULTS

Of the 19,736 genes represented on the microarray, expression of 378 genes was differentially regulated (215 upregulated and 163 downregulated), with at least a 2-fold change in expression (P <.05). The differentially regulated transcripts included genes known to be involved in several different biological processes, including signaling, DNA-dependent transcriptional regulation, immune response, proteolysis, and peptidolysis. Cluster analysis of the differentially regulated genes showed that at least 16 were downregulated by R142571 treatment at both of the doses used (1 and 10 mg/kg). In addition, 46 and 29 genes were downregulated at doses of 10 mg/kg and 1 mg/kg, respectively, as compared to the animals treated with vehicle.

CONCLUSION

The cytokine expression pattern in our data, suggests that the murine model exhibits a predominantlyT helper 2-type response, as observed in asthmatic human subjects. Based on this study, we suggest that this mouse model would be an appropriate system for screening new drug molecules for treatment of atopic asthma.

The effectiveness of antipsychotic medication in the management of behaviour problems in adults with intellectual disabilities

BACKGROUND

Psychopharmacological intervention in the management of behaviour problems in adults with intellectual disabilities (ID) has become a common treatment strategy. This has become a cause for concern, given that the evidence for its effectiveness is uncertain and most drugs are not licensed for this use.

METHODS

A comprehensive systematic review of empirical research on the effectiveness of antipsychotic medication was conducted. Electronic and manual searches of literature were conducted. Stringent scientific methodology determined those primary trials that were worthy of inclusion.

RESULTS

This review revealed one randomized controlled trial (RCT), one controlled, four uncontrolled prospective and three retrospective case series studies in adults. Additionally, two studies in both adults and children--one crossover RCT and one prospective controlled trial--were found.

CONCLUSION

Presently, there is RCT-based evidence for risperidone to be effective in both adults and children; however, this treatment carries a certain amount of risk associated with adverse effects. There is also evidence to support the use of other antipsychotics, primarily atypicals, but the evidence is based on noncontrolled case studies. There is currently not enough evidence available to recommend specific medication for specific behaviour problems. Before prescribing medication, clinicians should carry out a thorough assessment of behaviour, including its causes and consequences, and draw up a formulation providing the rationale for the prescribed intervention after considering all medication- and nonmedication-based management options.

The effectiveness of antidepressant medication in the management of behaviour problems in adults with intellectual disabilities: a systematic review

BACKGROUND

A comprehensive systematic review was performed to establish the current evidence base regarding the effectiveness of antidepressant medication for the management of behaviour problems in adults with intellectual disabilities.

METHOD

An electronic search of PsycInfo, Embase, Medline and Cinahl databases was conducted spanning the time period 1990 to October 2005 for primary trials. This was supplemented by hand searching and cross-referencing of relevant reviews. Strict scientific methodology requirements were formulated that the studies had to meet in order to merit inclusion in this review.

RESULTS

One crossover randomized controlled trial in a small cohort, seven prospective uncontrolled trials and two retrospective studies were yielded in the search. Of these, one explored the effectiveness of the tricyclic antidepressant--clomipramine, and nine considered various selective serotonin reuptake inhibitors (SSRIs).

CONCLUSION

Evidence based primarily on a small number of either prospective or retrospective case studies that included a small number of participants and often used non-validated outcome measures for a short period of follow-up, suggests that antidepressants, particularly SSRIs, show improvement of aggression and self-injurious behaviour on average in less than 50% of cases and the rest show either no improvement or deterioration. The effect is most pronounced in the presence of an underlying anxiety or an associated diagnosis of obsessive-compulsive disorder. Most studies have highlighted the concern regarding adverse effects.

Pulmonary atresia with intact ventricular septum and major aortopulmonary collaterals: association with deletion 22q11.2

We describe the first association of pulmonary atresia, intact ventricular septum, and absent central pulmonary arteries with deletion 22q11.2. The pulmonary blood flow was derived from major aortopulmonary collaterals. The role of the deletion in pulmonary arborization is discussed.

Inhibition of attaching and effacing lesion formation following enteropathogenic Escherichia coli and Shiga toxin-producing E. coli infection

Enteropathogenic Escherichia coli (EPEC) and Shiga toxin-producing E. coli (STEC) induce cytoskeletal changes in infected epithelial cells. To further characterize host cytosolic responses to infection, a series of specific cell-signaling inhibitors were employed. Initial bacterial adhesion to HEp-2 epithelial cells was not reduced, whereas alpha-actinin accumulation in infected cells was blocked by a phosphoinositide-specific phospholipase C inhibitor (ET-18-OCH3), phosphoinositide 3-kinase inhibitors (wortmannin and LY294002), and a 5-lipoxygenase inhibitor, nordihydroguaretic acid. A cyclooxygenase-2 inhibitor (NS-398), however, did not block alpha-actinin reorganization in response to EPEC and STEC infections. Understanding signal transduction responses to enteric pathogens could provide the basis for the development of novel therapeutic strategies.

A novel and highly divergent Arabidopsis cyclin isolated by complementation in budding yeast

A novel cyclin, CycJ18, was isolated by complementation of G1 cyclin-deficient budding yeast with an Arabidopsis cDNA library. CycJ18 shares only 20% identity in its conserved cyclin box domain with other cyclins, and is predominantly expressed in young seedlings. CycJ18 is a member of a potential new plant cyclin class.

Cell cycle arrest mediated by a pyridopyrimidine is not abrogated by over-expression of Bcl-2 and cyclin D1

Inhibition of cyclin dependent kinases (Cdks) is of pivotal importance in tumor cell biology as these kinases are the drivers of cell proliferation. This inhibition can be achieved either by naturally occurring biological proteins or by small molecule compounds. They cause cell cycle arrest and/or apoptosis depending upon the specificity and efficacy of the inhibitor in question. We have reported earlier that specific pyridopyrimidines (novel Cdk inhibitors) cause cell cycle arrest in mink lung epithelial cells and the arrest is abrogated by over-expression of Cdk4. In contrast, we show here that one of these inhibitors effectively maintains cell cycle arrest in a leukemic or a breast cancer cell line even after the respective cells over-express an oncogene, either Bcl-2 or cyclin D1. However, in the leukemic cells, Bcl-2 over-expression suppresses apoptosis induced by the pyridopyrimidine. Thus, novel Cdk inhibitors can prove to be useful chemical genetics tools for understanding the underlying mechanisms of growth arrest and/or apoptosis in normal versus tumor cells. This could also lead to the development of improved inhibitors of cell proliferation.

Selective in vivo and in vitro effects of a small molecule inhibitor of cyclin-dependent kinase 4

BACKGROUND

Cyclin-dependent kinase 4 (Cdk4) represents a prime target for the treatment of cancer because most human cancers are characterized by overexpression of its activating partner cyclin D1, loss of the natural Cdk4-specific inhibitor p16, or mutation(s) in Cdk4's catalytic subunit. All of these can cause deregulated cell growth, resulting in tumor formation. We sought to identify a small molecule that could inhibit the kinase activity of Cdk4 in vitro and to then ascertain the effects of that inhibitor on cell growth and tumor volume in vivo.

METHODS

A triaminopyrimidine derivative, CINK4 (a chemical inhibitor of Cdk4), was identified by screening for compounds that could inhibit Cdk4 enzyme activity in vitro. Kinase assays were performed on diverse human Cdks and on other kinases that were expressed in and purified from insect cells to determine the specificity of CINK4. Cell cycle effects of CINK4 on tumor and normal cells were studied by flow cytometry, and changes in phosphorylation of the retinoblastoma protein (pRb), a substrate of Cdk4, were determined by western blotting. The effect of the inhibitor on tumor growth in vivo was studied by use of tumors established through xenografts of HCT116 colon carcinoma cells in mice. Statistical tests were two-sided.

RESULTS

CINK4 specifically inhibited Cdk4/cyclin D1 in vitro. It caused growth arrest in tumor cells and in normal cells and prevented pRb phosphorylation. CINK4 treatment resulted in statistically significantly (P: =.031) smaller mean tumor volumes in a mouse xenograft model.

CONCLUSIONS

Like p16, the natural inhibitor of Cdk4, CINK4 inhibits Cdk4 activity in vitro and slows tumor growth in vivo. The specificity of CINK4 for Cdk4 raises the possibility that this small molecule or one with a similar structure could have therapeutic value.

Inhibition of cyclin-dependent kinase 4 (Cdk4) by fascaplysin, a marine natural product

Small chemical molecules that interfere with biological proteins could be useful for gaining insight into the complex biochemical processes in mammalian cells. Cdk4 is a key protein whose activity is required not only for emergence of cells from quiescence but also at the G1/S transition in the cell cycle and which is misregulated in 60-70% of human cancers. We set out to identify chemical inhibitors of Cdk4 and discovered that, in vitro, fascaplysin specifically inhibited Cdk4. Molecular modelling based on the crystal structure of Cdk2 suggests that fascaplysin inhibits Cdk4 by binding to the ATP pocket of the kinase. Treatment of tumour (p16(-), pRb(+)) and normal (p16(+), pRb(+)) cell lines with fascaplysin caused G1 arrest and prevented pRb phosphorylation at sites implicated as being specific for Cdk4 kinase. Fascaplysin will therefore prove to be a useful tool in studying the consequence of Cdk4 inhibition, especially in cells containing inactivated p16.

Novel Cdk inhibitors restore TGF-beta sensitivity in cdk4 overexpressing epithelial cells

Transforming growth factor-beta (TGF-beta) is a potent mitogen that effects a wide variety of cells by blocking cell growth. TGF-beta acts by interacting with components of cell cycle machinery to cause G1 arrest and in mink lung epithelial cells (Mv1Lu) it does so by inhibiting Cdk4 synthesis. Overexpression of Cdk4 in these cells (B7) renders them resistant to the effects of TGF-beta. Here we report that two novel Cdk inhibitors (pyridopyrimidines) that not only inhibit Cdk4 and Cdk2 in an in vitro kinase assay but also, in the absence of TGF-beta, block growth of Mv1Lu cells in G1 more efficiently than their B7 (overexpressing Cdk4) counterparts. Interestingly, these inhibitors restored sensitivity of B7 cells towards TGF-beta. This may have implications for the treatment of tumors that have lost TGF-beta responsiveness due to deregulated cellular growth in vivo. These Cdk inhibitors could therefore be used in conjunction with TGF-beta to understand the mechanism of growth arrest in normal versus tumour cells.

Macleod's syndrome presenting with spontaneous pneumothorax

A 19-year-old woman with a recent history of recurrent bronchitis presented with a spontaneous left pneumothorax. Review of the chest radiographs revealed features of Macleod's syndrome on the same side, with unilateral lucency and hypoplastic hilar vessels. To our knowledge this is the first report of Macleod's syndrome presenting with spontaneous pneumothorax.

Fulminant psittacosis requiring mechanical ventilation and demonstrating serological cross-reactivity between Legionella longbeachae and Chlamydia psittaci

Chlamydia psittaci infection typically causes a mild respiratory illness in humans. Severe respiratory failure requiring mechanical ventilation or intensive care therapy is an uncommon development. The aetiological agents causing severe community acquired pneumonia often remain undetermined. Serological tests may aid in diagnosis. We present two cases of fulminant psittacosis, one demonstrating early cross-reactivity with Legionella longbeachae.

Optimal feeding for the malnourished CAPD patient

Protein-calorie malnutrition is present in a significant percentage of dialysis patients (1). In CAPD (Continuous Ambulatory Peritoneal Dialysis) patients, constant glucose absorption from dialysate may displace other calorie sources, such as protein, and may suppress the appetite thus contributing to malnutrition.

Neurotrophic immunophilin ligands stimulate structural and functional recovery in neurodegenerative animal models

Although immunosuppressant immunophilin ligands promote neurite outgrowth in vitro, their neurotrophic activities are clearly independent of their immunosuppressive activity. In the present report, a novel nonimmunosuppressive immunophilin ligand, GPI-1046 (3-(3-pyridyl)-1-propyl (2S)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidinecarboxylate+ ++) is described. In vitro, GPI-1046 bound to FK506 binding protein-12 and elicited neurite outgrowth from sensory neuronal cultures with picomolar potency with maximal effects comparable to nerve growth factor. In vivo, GPI-1046 stimulated the regeneration of lesioned sciatic nerve axons and myelin levels. In the central nervous system, GPI-1046 promoted protection and/or sprouting of serotonin-containing nerve fibers in somatosensory cortex following parachloroamphetamine treatment. GPI-1046 also induced regenerative sprouting from spared nigrostriatal dopaminergic neurons following 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxicity in mice or 6-hydroxydopamine (6-OHDA) toxicity in rats. The rotational abnormality in 6-OHDA treated rats was alleviated by GPI-1046. These neurotrophic actions in multiple models suggest therapeutic utility for GPI-1046 in neurodegenerative diseases.

Prolonged survival after massive pulmonary embolism in a patient with atrial septal defect and mass in the right ventricle

Unless thrombolytic or surgical therapy is rapidly available, massive pulmonary embolism in both pulmonary arteries invariably results in instantaneous death. A patient is presented with congenital atrial septal defect and right ventricular thrombus who developed extensive bilateral pulmonary embolism with an apparently prolonged survival. The ante- and postmortem findings represent the unusual and interesting aspects of this particular case.

Modulation of cyclin transcript levels in cultured cells of Arabidopsis thaliana

Previous studies on the cell cycle of Arabidopsis thaliana have been hindered by the lack of synchronous cell culture systems. We have used liquid callus cultures and a cycloheximide-synchronized suspension culture of Arabidopsis to investigate changes in cyclin transcript levels in response to exogenous auxin, cytokinin, and nutrients, and during the cell cycle. CYCD1 (delta 1) transcript was virtually undetectable in liquid-cultured callus or suspension-culture cells. CYCD2 (delta 2) transcript levels were largely unaffected by the readdition of phytohormones or nitrate to the growth medium, and remained constant throughout the cell cycle in suspension-culture cells. CYCD3 (delta 3) transcript levels were strongly dependent on nitrate, and were induced at the G1/S transition following phytohormone readdition. In synchronized suspension-culture cells, CYCD3 transcript accumulated during the S phase, and remained constant thereafter. These results support the hypothesis that D cyclins function as part of the cellular machinery that integrates diverse signals impinging upon commitment to cell division. In synchronized cells transcripts of the mitotic cyclins CYC1, CYC2, and CYC3 reached a maximum with peak mitotic index, but CYC3 transcript levels increased earlier than those of CYC1 or CYC2. The kinetics of accumulation of CYC transcript levels support their classification as A-type (CYC3) and B-type (CYC1 and CYC2) cyclins, respectively.

Basopenia as an indicator of ovulation (a short term clinical study)

In the present study 60 cases age ranging from 18-40 years were studied for variation in the absolute basophil count on the different days of menstrual cycle. At the time of ovulation a statistically significant decrease in the number of basophil count was noted. The decrease in the number of basophil at mid cycle coincided with the irregular follicle seen by sonography, which indicated ovulation. The basophil count then increased during the luteal phase. Basopenia at the time of ovulation was probably due to migration of these cells from the peripheral blood towards the rupturing follicle for the release of histamine required for ovulation.

Polysaccharide side chains are not required for attaching and effacing adhesion of Escherichia coli O157:H7

Escherichia coli of the serotype O157:H7 is an enterohemorrhagic human pathogen which demonstrates attaching and effacing adhesion to colonocytes in vivo and to epithelial cells grown in tissue culture. Transposon TnphoA mutants of E. coli O157:H7 strain CL-8 were produced. Two of 300 alkaline phosphatase positive mutants, designated JB6 and JB27, did not express O157 side chains as assessed by agglutination with specific polyclonal O157 antiserum, silver staining of lipopolysaccharide extracts separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Western immunoblots with polyclonal O157-specific antiserum. Both O157-negative mutants and the parent strain demonstrated localized adherence to HEp-2 cells when examined by Giemsa staining and bright-field microscopy. Furthermore, both O157-negative mutants showed enhanced adherence to HEp-2 cells compared with the parent strain when assessed by quantification of adherent bacterial CFUs. The parent strain, CL-8, and both of the mutants produced fluorescent foci when adherent bacteria and HEp-2 cells were stained with fluorescein isothiocyanate-labelled phalloidin. Transmission electron microscopy confirmed attaching and effacing adherence of strain CL-8 and the OO7-negative mutants to HEp-2 cells. These findings indicate that mutants deficient in O157 polysaccharide repeats exhibit adherence to tissue culture cells in vitro and that O157 polysaccharide repeats are not required to produce the attaching and effacing lesion.

Alpha-actinin accumulation in epithelial cells infected with attaching and effacing gastrointestinal pathogens

Fluorescent F-actin staining utilizing phalloidin, a highly toxic mushroom poison, is used as an indirect test to detect attaching and effacing (AE) bacteria. A study was done to determine if accumulation of alpha-actinin in infected tissue culture cells is a consistent feature and whether it corresponds with the AE response. Rearrangement of alpha-actinin was detected using immunofluorescence microscopy by incubation of infected cells with a murine monoclonal anti-alpha-actinin antibody. Foci of alpha-actinin-specific fluorescence corresponding to areas of bacterial adhesion were detected by transmission electron microscopy in HEp-2 and gastric KATO-III cells infected with only those bacterial strains that formed AE lesions. Therefore, this study shows that alpha-actinin accumulation is a consistent, specific manifestation of the AE phenotype and forms the basis for the development of a safe alternative test for detecting AE bacteria.

Effect of intraperitoneal ATP on tumor growth and bone marrow radiation tolerance

Transplants of a spontaneous murine fibrosarcoma (FSaII) treated with intraperitoneal ATP were studied in vitro, and in both C3H and nu/nu mice. Daily ATP treatment prolonged tumor volume doubling time in vivo and in vitro. Daily ATP treatments at the maximally tolerated dose (2 mmol/kg i.p.) did not significantly affect the pH or the PCr/Pi, or beta ATP/Pi ratios (measured by MRS). In contrast to the reduced tumor growth rate, there was no change in bone marrow recovery after whole body irradiation. ATP is minimally toxic to animals at active dose levels. It slows tumor growth rate without adversely affecting bone marrow radiation tolerance. ATP might therefore be useful as a biological modifier of chemotherapy or radiation therapy.