ATOMDANCE: Kernel-based denoising and choreographic analysis for protein dynamic comparison

Comparative methods in molecular evolution and structural biology rely heavily upon the site-wise analysis of DNA sequence and protein structure, both static forms of information. However, it is widely accepted that protein function results from nanoscale nonrandom machine-like motions induced by evolutionarily conserved molecular interactions. Comparisons of molecular dynamics (MD) simulations conducted between homologous sites representative of different functional or mutational states can potentially identify local effects on binding interaction and protein evolution. In addition, comparisons of different (i.e., nonhomologous) sites within MD simulations could be employed to identify functional shifts in local time-coordinated dynamics indicative of logic gating within proteins. However, comparative MD analysis is challenged by the large fraction of protein motion caused by random thermal noise in the surrounding solvent. Therefore, properly denoised MD comparisons could reveal functional sites involving these machine-like dynamics with good accuracy. Here, we introduce ATOMDANCE, a user-interfaced suite of comparative machine learning-based denoising tools designed for identifying functional sites and the patterns of coordinated motion they can create within MD simulations. ATOMDANCE-maxDemon4.0 employs Gaussian kernel functions to compute site-wise maximum mean discrepancy between learned features of motion, thereby assessing denoised differences in the nonrandom motions between functional or evolutionary states (e.g., ligand bound versus unbound, wild-type versus mutant). ATOMDANCE-maxDemon4.0 also employs maximum mean discrepancy to analyze potential random amino acid replacements allowing for a site-wise test of neutral versus nonneutral evolution on the divergence of dynamic function in protein homologs. Finally, ATOMDANCE-Choreograph2.0 employs mixed-model analysis of variance and graph network to detect regions where time-synchronized shifts in dynamics occur. Here, we demonstrate ATOMDANCE's utility for identifying key sites involved in dynamic responses during functional binding interactions involving DNA, small-molecule drugs, and virus-host recognition, as well as understanding shifts in global and local site coordination occurring during allosteric activation of a pathogenic protease.

Evolution of drug resistance drives destabilization of flap region dynamics in HIV-1 protease

The HIV-1 protease is one of several common key targets of combination drug therapies for human immunodeficiency virus infection and acquired immunodeficiency syndrome. During the progression of the disease, some individual patients acquire drug resistance due to mutational hotspots on the viral proteins targeted by combination drug therapies. It has recently been discovered that drug-resistant mutations accumulate on the "flap region" of the HIV-1 protease, which is a critical dynamic region involved in nonspecific polypeptide binding during invasion and infection of the host cell. In this study, we utilize machine learning-assisted comparative molecular dynamics, conducted at single amino acid site resolution, to investigate the dynamic changes that occur during functional dimerization and drug binding of wild-type and common drug-resistant versions of the main protease. We also use a multiagent machine learning model to identify conserved dynamics of the HIV-1 main protease that are preserved across simian and feline protease orthologs. We find that a key conserved functional site in the flap region, a solvent-exposed isoleucine (Ile50) that controls flap dynamics is functionally targeted by drug resistance mutations, leading to amplified molecular dynamics affecting the functional ability of the flap region to hold the drugs. We conclude that better long-term patient outcomes may be achieved by designing drugs that target protease regions that are less dependent upon single sites with large functional binding effects.

Generation of a high yield vaccine backbone for influenza B virus in embryonated chicken eggs

Influenza B virus (IBV) strains are one of the components of seasonal influenza vaccines in both trivalent and quadrivalent formulations. The vast majority of these vaccines are produced in embryonated chickens' eggs. While optimized backbones for vaccine production in eggs exist and are in use for influenza A viruses, no such backbones exist for IBVs, resulting in unpredictable production yields. To generate an optimal vaccine seed virus backbone, we have compiled a panel of 71 IBV strains from 1940 to present day, representing the known temporal and genetic variability of IBV circulating in humans. This panel contains strains from the B/Victoria/2/87-like lineage, B/Yamagata/16/88-like lineage and the ancestral lineage that preceded their split to provide a diverse set that would help to identify a suitable backbone which can be used in combination with hemagglutinin (HA) and neuraminidase (NA) glycoproteins from any IBV strain to be incorporated into the seasonal vaccine. We have characterized and ranked the growth profiles of the 71 IBV strains and the best performing strains were used for co-infection of eggs, followed by serial passaging to select for high-growth reassortant viruses. After serial passaging, we selected 10 clonal isolates based on their growth profiles assessed by hemagglutination and plaque-forming units. We then generated reverse genetics systems for the three clones that performed best in growth curves. The selected backbones were then used to generate different reassortant viruses with HA/NA combinations from high and low titer yielding wild type IBV. When the growth profiles of the recombinant reassortant viruses were tested, the low titer yielding HA/NA viruses with the selected backbones yielded higher titers similar to those from high titer yielding HA/NA combinations. The use of these IBV backbones with improved replication in eggs might increase yields for the influenza B virus components of seasonal influenza virus vaccines.

Persistent cross-species SARS-CoV-2 variant infectivity predicted via comparative molecular dynamics simulation

Widespread human transmission of SARS-CoV-2 highlights the substantial public health, economic and societal consequences of virus spillover from wildlife and also presents a repeated risk of reverse spillovers back to naive wildlife populations. We employ comparative statistical analyses of a large set of short-term molecular dynamic (MD) simulations to investigate the potential human-to-bat (genus Rhinolophus) cross-species infectivity allowed by the binding of SARS-CoV-2 receptor-binding domain (RBD) to angiotensin-converting enzyme 2 (ACE2) across the bat progenitor strain and emerging human strain variants of concern (VOC). We statistically compare the dampening of atom motion across protein sites upon the formation of the RBD/ACE2 binding interface using various bat versus human target receptors (i.e. bACE2 and hACE2). We report that while the bat progenitor viral strain RaTG13 shows some pre-adaption binding to hACE2, it also exhibits stronger affinity to bACE2. While early emergent human strains and later VOCs exhibit robust binding to both hACE2 and bACE2, the delta and omicron variants exhibit evolutionary adaption of binding to hACE2. However, we conclude there is a still significant risk of mammalian cross-species infectivity of human VOCs during upcoming waves of infection as COVID-19 transitions from a pandemic to endemic status.

Identifying vaccine escape sites via statistical comparisons of short-term molecular dynamics

The identification of viral mutations that confer escape from antibodies is crucial for understanding the interplay between immunity and viral evolution. We describe a molecular dynamics (MD)-based approach that goes beyond contact mapping, scales well to a desktop computer with a modern graphics processor, and enables the user to identify functional protein sites that are prone to vaccine escape in a viral antigen. We first implement our MD pipeline to employ site-wise calculation of Kullback-Leibler divergence in atom fluctuation over replicate sets of short-term MD production runs thus enabling a statistical comparison of the rapid motion of influenza hemagglutinin (HA) in both the presence and absence of three well-known neutralizing antibodies. Using this simple comparative method applied to motions of viral proteins, we successfully identified in silico all previously empirically confirmed sites of escape in influenza HA, predetermined via selection experiments and neutralization assays. Upon the validation of our computational approach, we then surveyed potential hotspot residues in the receptor binding domain of the SARS-CoV-2 virus in the presence of COVOX-222 and S2H97 antibodies. We identified many single sites in the antigen-antibody interface that are similarly prone to potential antibody escape and that match many of the known sites of mutations arising in the SARS-CoV-2 variants of concern. In the Omicron variant, we find only minimal adaptive evolutionary shifts in the functional binding profiles of both antibodies. In summary, we provide an inexpensive and accurate computational method to monitor hotspots of functional evolution in antibody binding footprints.

Evaluation of a Conceptualised Learning Design for the Development of Techno-Pedagogic Competencies among Pre-Service Teachers

The present study aims to evaluate a conceptualised learning design for the growth of techno-pedagogic competencies among Pre-Service Teachers (PST). A teaching experiment is conducted for assessing the effectiveness of the conceptualised learning design by implementing it in a two-year teacher training programme for one year on 36 PST. The progress in the techno-pedagogic competencies’ growth is measured through the self-reporting rating scale, assessment of lesson activities prepared by the PST and semi-structured interview. The result of repeated measure ANOVA statistically signifies the growth of techno-pedagogic competencies amongst PST who participated in the teaching experiment. The assessment of lesson activities further illustrated the growth of techno-pedagogic competencies. PST also reported that they have learned new ways of integrating technology into teaching and have become a more confident user of computers.

Statistical machine learning for comparative protein dynamics with the DROIDS/maxDemon software pipeline

Comparative analysis of protein structure or sequence alignments often ignores the protein dynamics and function. We offer a graphical user interface to a computing pipeline, complete with molecular visualization, enabling the biophysical simulation and statistical comparison of two-state functional protein dynamics (i.e., single unbound state vs. complex with a ligand, DNA, or protein). We utilize multi-agent machine learning classifiers to identify functionally conserved dynamic motions and compare them in genetic or drug-class variants.

For complete details on the use and execution of this profile, please refer to Babbitt et al. (2020b, 2020a, 2018) and Rynkiewicz et al. (2021).

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A pipeline for the site-wise statistical comparison of molecular dynamics

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Analyzes mutational or functional changes in protein dynamics

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Utilizes machine learning to identify regions of conserved dynamics

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Utilizes information theoretics to identify site of coordinated dynamics

The Human Antibody Response to the Influenza Virus Neuraminidase Following Infection or Vaccination

The influenza virus neuraminidase (NA) is primarily involved in the release of progeny viruses from infected cells—a critical role for virus replication. Compared to the immuno-dominant hemagglutinin, there are fewer NA subtypes, and NA experiences a slower rate of antigenic drift and reduced immune selection pressure. Furthermore, NA inhibiting antibodies prevent viral egress, thus preventing viral spread. Anti-NA immunity can lessen disease severity, reduce viral shedding, and decrease viral lung titers in humans and various animal models. As a result, there has been a concerted effort to investigate the possibilities of incorporating immunogenic forms of NA as a vaccine antigen in future vaccine formulations. In this review, we discuss NA-based immunity and describe several human NA-specific monoclonal antibodies (mAbs) that have a broad range of protection. We also review vaccine platforms that are investigating NA antigens in pre-clinical models and their potential use for next-generation influenza virus vaccines. The evidence presented here supports the inclusion of immunogenic NA in future influenza virus vaccines.

An immuno-assay to quantify influenza virus hemagglutinin with correctly folded stalk domains in vaccine preparations

The standard method to quantify the hemagglutinin content of influenza virus vaccines is the single radial immunodiffusion assay. This assay primarily relies on polyclonal antibodies against the head domain of the influenza virus hemagglutinin, which is the main target antigen of influenza virus vaccines.

Novel influenza virus vaccine candidates that redirect the immune response towards the evolutionary more conserved hemagglutinin stalk, including chimeric hemagglutinin and headless hemagglutinin constructs, are highly dependent on the structural integrity of the protein to present conformational epitopes for neutralizing antibodies. In this study, we describe a novel enzyme-linked immunosorbent assay that allows quantifying the amount of hemagglutinin with correctly folded stalk domains and which could be further developed into a potency assay for stalk-based influenza virus vaccines.

Application of radiopaque micro-particle fillers for 3-D imaging of periodontal pocket analogues using cone beam CT

BACKGROUND

Periodontitis is an infectious/inflammatory disease most often diagnosed by deepening of the gingival sulcus, which leads to periodontal pockets (PPs) conventional manual periodontal probing does not provide detailed information on the three-dimensional (3-D) nature of PPs.

OBJECTIVES

To determine whether accurate 3-D analyses of the depths and volumes of calibrated PP analogues (PPAs) can be obtained by conventional cone beam computed tomography (CBCT) coupled with novel radiopaque micro-particle fillers (described in the companion paper) injected into the PPAs.

METHODS

Two PPA models were employed: (1) a human skull model with artificial gingiva applied to teeth with alveolar bone loss and calibrated PPAs, and (2) a pig jaw model with alveolar bone loss and surgically-induced PPAs The PPAs were filled with controlled amounts of radiopaque micro-particle filler using volumetric pipetting Inter-method and intra-method agreement tests were then used to compare the PPA depths and volumes obtained from CBCT images with values obtained by masked examiners using calibrated manual methods.

RESULTS

Significant inter-method agreement (0.938-0.991) and intra-method agreement (0.94-0.99) were obtained when comparing analog manual data to digital CBCT measurements enabled by the radiopaque filler.

SIGNIFICANCE

CBCT imaging with radiopaque micro-particle fillers is a plausible means of visualizing and digitally assessing the depths, volumes, and 3-D shapes of PPs This approach could transform the diagnosis and treatment planning of periodontal disease, with particular initial utility in complex cases Efforts to confirm the clinical practicality of these fillers are currently in progress.

Small Molecule Chelators Reveal That Iron Starvation Inhibits Late Stages of Bacterial Cytokinesis

Bacterial cell division requires identification of the division site, assembly of the division machinery, and constriction of the cell envelope. These processes are regulated in response to several cellular and environmental signals. Here, we use small molecule iron chelators to characterize the surprising connections between bacterial iron homeostasis and cell division. We demonstrate that iron starvation downregulates the transcription of genes encoding proteins involved in cell division, reduces protein biosynthesis, and prevents correct positioning of the division machinery at the division site. These combined events arrest the constriction of the cell during late stages of cytokinesis in a manner distinct from known mechanisms of inhibiting cell division. Overexpression of genes encoding cell division proteins or iron transporters partially suppresses the biological activity of iron chelators and restores growth and division. We propose a model demonstrating the effect of iron availability on the regulatory mechanisms coordinating division in response to the nutritional state of the cell.

Novel Cross-Reactive Monoclonal Antibodies against Ebolavirus Glycoproteins Show Protection in a Murine Challenge Model

Out of an estimated 31,100 cases since their discovery in 1976, ebolaviruses have caused approximately 13,000 deaths. The vast majority (∼11,000) of these occurred during the 2013-2016 West African epidemic. Three out of five species in the genus are known to cause Ebola Virus Disease in humans. Several monoclonal antibodies against the ebolavirus glycoprotein are currently in development as therapeutics. However, there is still a paucity of monoclonal antibodies that can cross-react between the glycoproteins of different ebolavirus species, and the mechanism of these monoclonal antibody therapeutics is still not understood in detail. Here, we generated a panel of eight murine monoclonal antibodies (MAbs) utilizing a prime-boost vaccination regimen with a Zaire ebolavirus glycoprotein expression plasmid followed by infection with a vesicular stomatitis virus expressing the Zaire ebolavirus glycoprotein. We tested the binding breadth of the resulting monoclonal antibodies using a set of recombinant surface glycoproteins from Reston, Taï Forest, Bundibugyo, Zaire, Sudan, and Marburg viruses and found two antibodies that showed pan-ebolavirus binding. An in vivo Stat2-/- mouse model was utilized to test the ability of these MAbs to protect from infection with a vesicular stomatitis virus expressing the Zaire ebolavirus glycoprotein. Several of our antibodies, including the broadly binding ones, protected mice from mortality despite lacking neutralization capability in vitro, suggesting their protection may be mediated by Fc-FcR interactions. Indeed, three antibodies displayed cellular phagocytosis and/or antibody-dependent cell-mediated cytotoxicity in vitro Our antibodies, specifically the two identified cross-reactive monoclonal antibodies (KL-2E5 and KL-2H7), might add to the understanding of anti-ebolavirus humoral immunity.IMPORTANCE This study describes the generation of a panel of novel anti-ebolavirus glycoprotein monoclonal antibodies, including two antibodies with broad cross-reactivity to all known ebolavirus species. The antibodies were raised using a heterologous DNA-viral vector prime-boost regimen, resulting in a high proportion of cross-reactive antibodies (25%). Similar vaccination regimens have been used successfully to induce broad protection against influenza viruses in humans, and our limited data indicate that this might be a useful strategy for filovirus vaccines as well. Several of our antibodies showed protective efficacy when tested in a novel murine challenge model and may be developed into future therapeutics.

Loss to follow-up among children in pre-ART care under the National AIDS Programme, Tamil Nadu, South India

Setting: Children aged <15 years constitute 7% of all people living with the human immunodeficiency virus (HIV) in India. A previous study from an antiretroviral therapy (ART) centre in south India reported 82% loss to follow-up (LTFU) among children in pre-ART care (2006-2011). Objective: To assess the proportion of LTFU within 1 year of registration among HIV-infected children (aged < 15 years) registered in all 43 ART centres in the state of Tamil Nadu, India, during the year 2012. Design: This was a retrospective cohort study involving a review of programme records. Results: Of 656 children registered for HIV care, 20 (3%) were not assessed for ART eligibility. Of those remaining, 226 (36%) were not ART eligible and entered pre-ART care. Among these, at 1 year of registration, 50 (22%) were LTFU, 40 (18%) were transferred out and 136 (60%) were retained in care at the same centre. The child's age, sex, World Health Organization stage or occurrence of opportunistic infection were not associated with LTFU. Conclusion: One in five children registered under pre-ART care were lost to follow-up. Stronger measures to prevent LTFU and reinforce retrieval actions are necessary in the existing National HIV Programme.

Physician's advice on quitting smoking in HIV and TB patients in south India: a randomised clinical trial

Setting: National Institute for Research in Tuberculosis, Madurai, India. Objective: To determine the efficacy of physician's advice on quitting smoking compared with standard counselling in patients with tuberculosis (TB) and patients with human immunodeficiency virus (HIV) infection. Design/Methods: This was a clinical trial conducted in Madurai, south India, among 160 male patients (80 with TB and 80 with HIV), randomised and stratified by nicotine dependence (low/high according to the Fagerström scale), who received physician's advice with standard counselling or standard counselling alone for smoking cessation. Abstinence at 1 month was assessed by self-report and carbon monoxide breath analysis. Results: The patients' mean age was 39.4 years (SD 8.5). Overall, 35% of the patients had high nicotine dependence. Most patients (41%) smoked both cigarettes and bidis. In a combined analysis including both the HIV and the TB groups, quit rates were 41% of the 68 patients in the physician group and 35% of the 68 patients in the standard counselling arm. Conclusions: Physician's advice to quit smoking delivered to patients with TB or HIV is feasible and acceptable. Smoking cessation could easily be initiated in TB patients in programme settings. Future studies should assess long-term abstinence rates with a larger sample size to demonstrate the efficacy of physician's advice.

Targeting quinolone- and aminocoumarin-resistant bacteria with new gyramide analogs that inhibit DNA gyrase

Bacterial DNA gyrase is an essential type II topoisomerase that enables cells to overcome topological barriers encountered during replication, transcription, recombination, and repair. This enzyme is ubiquitous in bacteria and represents an important clinical target for antibacterial therapy. In this paper we report the characterization of three exciting new gyramide analogs-from a library of 183 derivatives-that are potent inhibitors of DNA gyrase and are active against clinical strains of gram-negative bacteria (Escherichia coli, Shigella flexneri, and Salmonella enterica; 3 of 10 wild-type strains tested) and gram-positive bacteria (Bacillus spp., Enterococcus spp., Staphylococcus spp., and Streptococcus spp.; all 9 of the wild-type strains tested). E. coli strains resistant to the DNA gyrase inhibitors ciprofloxacin and novobiocin display very little cross-resistance to these new gyramides. In vitro studies demonstrate that the new analogs are potent inhibitors of the DNA supercoiling activity of DNA gyrase (IC50s of 47-170 nM) but do not alter the enzyme's ATPase activity. Although mutations that confer bacterial cells resistant to these new gyramides map to the genes encoding the subunits of the DNA gyrase (gyrA and gyrB genes), overexpression of GyrA, GyrB, or GyrA and GyrB together does not suppress the inhibitory effect of the gyramides. These observations support the hypothesis that the gyramides inhibit DNA gyrase using a mechanism that is unique from other known inhibitors.

Epicardial fat thickness: A surrogate marker of coronary artery disease - Assessment by echocardiography

OBJECTIVE

Epicardial fat is considered as indicator of cardiovascular risk. Several studies have tested the association between epicardial fat thickness (EFT) and coronary artery disease. The aim of our study is to test the hypothesis that echocardiographic EFT is a marker of coronary artery disease.

METHODS

One hundred and ten patients (70 males and 40 females with mean age of 51.5±10.6 and 52.6±9.6, respectively) admitted for coronary angiogram underwent assessment of epicardial fat thickness by echocardiography. Routine clinical examination, evaluation of risk factor profile, and anthropometric variables were also done. Epicardial fat thickness was measured on the free wall of right ventricle in parasternal long- and short-axis views at end-systole for 3 cardiac cycles.

RESULTS

Mean epicardial fat thickness in angiographically normal patients and acute coronary syndromes were 4.4±1.2 and 6.9±1.9, respectively. Epicardial fat thickness in males and females were not statistically different. Burden of coronary arterial lesions denoted by Gensini score shows linear association with epicardial fat thickness and the severity of the coronary disease.

CONCLUSION

Epicardial fat is independently and linearly associated with CAD and its severity.

Polar localization of Escherichia coli chemoreceptors requires an intact Tol-Pal complex

Subcellular biomolecular localization is critical for the metabolic and structural properties of the cell. The functional implications of the spatiotemporal distribution of protein complexes during the bacterial cell cycle have long been acknowledged; however, the molecular mechanisms for generating and maintaining their dynamic localization in bacteria are not completely understood. Here we demonstrate that the trans-envelope Tol-Pal complex, a widely conserved component of the cell envelope of Gram-negative bacteria, is required to maintain the polar positioning of chemoreceptor clusters in Escherichia coli. Localization of the chemoreceptors was independent of phospholipid composition of the membrane and the curvature of the cell wall. Instead, our data indicate that chemoreceptors interact with components of the Tol-Pal complex and that this interaction is required to polarly localize chemoreceptor clusters. We found that disruption of the Tol-Pal complex perturbs the polar localization of chemoreceptors, alters cell motility, and affects chemotaxis. We propose that the E. coli Tol-Pal complex restricts mobility of the chemoreceptor clusters at the cell poles and may be involved in regulatory mechanisms that co-ordinate cell division and segregation of the chemosensory machinery.

Antioxidant study of quercetin and their metal complex and determination of stability constant by spectrophotometry method

Quercetin found chelate cadmium ions, scavenge free radicals produced by cadmium. Hence new complex, quercetin with cadmium was synthesised, and the synthesised complex structures were determined by UV-vis spectrophotometry, infrared spectroscopy, thermogravimetry and differential thermal analysis techniques (UV-vis, IR, TGA and DTA). The equilibrium stability constants of quercetin-cadmium complex were determined by Job's method. The determined stability constant value of quercetin-cadminum complex at pH 4.4 is 2.27×10(6) and at pH 7.4 is 7.80×10(6). It was found that the quercetin and cadmium ion form 1:1 complex in both pH 4.4 and pH 7.4. The structure of the compounds was elucidated on the basis of obtained results. Furthermore, the antioxidant activity of the free quercetin and quercetin-cadmium complexes were determined by DPPH and ABTS assays.

FT-IR spectral studies on polluted soils from industrial area at Karaikal, Puducherry State, South India

Fourier transform infrared spectroscopy (FT-IR) has been carried out to analyze the chemical composition of soil samples. The soil samples were collected from an industrial environment at Karaikal, Union Territory of Pondicherry, South India. The FT-IR results indicate that soils have different composition, i.e., namely kaolinite, quartz, montmorillonite, aragonite, hematite, feldspar and calcite, respectively. From the spectral pattern, the chemical compositions of soil samples were identified. The quantitative estimations of kaolinite (1032 cm(-1) and 1634 cm(-1)), quartz (779 cm(-1), 692 cm(-1) and 464 cm(-1)), montmorillonite (3421 cm(-1)), organic material (2922 cm(-1)) and hematite (532 cm(-1)) were calculated using particular peaks of FT-IR studies spectrum. From the XRD pattern, the chemical compositions of soil samples were confirmed. In the study reveals that kaolinite and quartz minerals were predominant whereas montmorillonite and hematite are in moderate level, and organic materials are found in trace. Quantitative analyses of soils show that quartz (36%), kaolinite (34%), hematite (13%), montmorillonite (12%), illite (3%) and organic material (2%) are present in all the soil samples at various sites.

Drug related crisis in myasthenia gravis

Myasthenia gravis is an autoimmune disorder where antibodies against the nicotinic Ach receptor resulting in impaired transmission at the NM junction. A number of drugs have been reported to cause neuromuscular blockade and/or to increase weakness in myasthenia gravis. We report a case of myasthenia gravis in which the calcium channel blocker-nifedipine caused the worsening of the symptoms.

Photodynamic effects of two hydroxyanthraquinones

The aim of this work was to investigate the photodynamic action of electron-rich anthraquinones, viz., cynodontin (CYN) and cynodontin-5,8-dimethylether (CYNM). Both optical and EPR methods are used to detect the generation of singlet oxygen. Based on RNO bleaching, relative to rose bengal (RB), singlet oxygen generating efficiencies of CYN and CYNM are derived to be 0.055 and 0.254, respectively. The formation of superoxide anion via electron transfer to O2 was monitored by optical spectroscopy, using SOD-inhibitable cytochrome c reduction assay. The production of O2-* is enhanced in the presence of electron donors such as EDTA and NADH. Photolysis of CYN and CYNM in DMSO, in the presence of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), generates a multi-line EPR spectrum, characteristic of spin adduct mixture of O2-* and *OH. Both optical and ESR measurements indicate that O2-* (Type I) and 1O2 (Type II) paths are involved in CYN and CYNM photodynamic action.

Drug susceptibility of Mycobacterium leprae: a retrospective analysis of mouse footpad inoculation results from 1983 to 1997

We analysed the results of mouse foot pad (MFP) tests performed between 1983 and 1997 in our laboratory for the cases referred with clinical suspicion of relapse/drug resistance. A total of 214 cases, with clinical suspicion of relapse/drug resistance were investigated for susceptibility to the drugs of MDT by MFP inoculation. Among 96 inoculations that showed conclusive results, 81 (84%) were fully sensitive to dapsone, suggesting that most of the clinically suspected relapse is due to drug susceptible Mycobacterium leprae. Of the remaining 15 strains (16%) found resistant to dapsone, 13 (87%) were of high grade resistance and one strain each of intermediate grade and low grade dapsone resistance, suggesting that most of the dapsone resistance is secondary in nature. No case of rifampicin resistance was found. Only one case of combined dapsone and unconfirmed clofazimine resistance was found. No other combined multidrug resistance was observed in our analysis.

Consumer health information. What the research is telling us

BACKGROUND

Consumer health information is a necessary component of patient care and consumer participation.

OBJECTIVE

To outline the findings of the 'Assessing the Quality of Consumer Health Information Project' and discuss strategies for improving consumer information.

DISCUSSION

The pamphlets identified in this study were not developed with consumer input with consequent deficits apparent. Providers and consumers appeared to use the information for very different purposes but both groups were critical of the ambiguous terminology and lack of quantified data. The provision of relevant information is a fundamental prerequisite of consumer participation in decision making in health care. Such information needs to be available, accurate, and understandable.

In vitro selection of signaling aptamers

Reagentless biosensors that can directly transduce molecular recognition to optical signals should potentiate the development of sensor arrays for a wide variety of analytes. Nucleic acid aptamers that bind ligands tightly and specifically can be readily selected, but may prove difficult to adapt to biosensor applications. We have therefore attempted to develop selection methods that couple the broad molecular recognition properties of aptamers with signal transduction. Anti-adenosine aptamers were selected from a pool that was skewed to contain very few fluoresceinated uridines. The primary family of aptamers showed a doubling of relative fluorescence intensity at saturating concentrations of a cognate analyte, ATP, and could sense ATP concentrations as low as 25 microM. A single uridine was present in the best signaling aptamer. Surprisingly, other dyes could substitute for fluorescein and still specifically signal the presence of ATP, indicating that the single uridine functioned as a general "switch" for transducing molecular recognition to optical signals.

Stroke following scorpion sting

A 30 year old male presented with crossed buccofacial apraxia, apraxia for speech, Left UMN facial palsy and hemiplegia following scorpion sting. A cerebrovascular accident can develop following a scorpion sting due to venom-induced cerebral thrombosis.

The human heat-shock genes HSPA6 and HSPA7 are both expressed and localize to chromosome 1

HSPA6 is a member of the human heat-shock protein gene family, encoding a basic 70-kDa protein, with unique induction characteristics (Leung et al., 1990, Biochem. J. 267: 125-132). Hybridization analyses with a somatic cell hybrid DNA panel localized the gene to chromosome 1q. The highly related HSPA7 DNA sequence (Voellmy et al., 1985, Proc. Natl. Acad. Sci. USA 82: 4949-4953) colocalized. Both HSPA6 and HSPA7 represent functional genes, as determined by analyses of mRNA from heat-shocked human cells using specific oligonucleotides, although their pattern of expression differed. Neither mRNA was detected in the absence of heat stress. A BamHI polymorphism in the HSPA7 gene was present in a predominantly Asian population.