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Background: The demand for inpatient medical services increases during influenza season. A scoring system capable of identifying influenza patients at low risk death or ICU admission could help clinicians make hospital admission decisions., Methods: Hospitalized patients with laboratory confirmed influenza were identified over 3 influenza seasons at 25 Ontario hospitals. Each patient was assigned a score for 6 pneumonia severity and 2 sepsis scores using the first data available following their registration in the emergency room. In-hospital mortality and ICU admission were the outcomes. Score performance was assessed using the area under the receiver operating characteristic curve (AUC) and the sensitivity and specificity for identifying low risk patients (risk of outcome <5%)., Results: The cohort consisted of 607 adult patients. Mean age was 76 years, 12% of patients died (71/607) and 9% required ICU care (55/607). None of the scores examined demonstrated good discriminatory ability (AUC>or=0.80). The Pneumonia Severity Index (AUC 0.78, 95% CI 0.72-0.83) and the Mortality in Emergency Department Sepsis score (AUC 0.77, 95% 0.71-0.83) demonstrated fair predictive ability (AUC>or=0.70) for in-hospital mortality. The best predictor of ICU admission was SMART-COP (AUC 0.73, 95% CI 0.67-0.79). All other scores were poor predictors (AUC <0.70) of either outcome. If patients classified as low risk for in-hospital mortality using the PSI were discharged, 35% of admissions would have been avoided., Conclusions: None of the scores studied were good predictors of in-hospital mortality or ICU admission. The PSI and MEDS score were fair predictors of death and if these results are validated, their use could reduce influenza admission rates significantly.

The Wireless Personal Area Network (WPAN) is one of the fledging paradigms that the next generation of wireless systems is sprouting towards. Among them, a more specific category is the Wireless Body Area Network (WBAN) used for health monitoring. On the other hand, Ultra-Wideband (UWB) comes with a number of desirable features at the physical layer for wireless communications. One big challenge in adoption of UWB in WBAN is the fact that signals get attenuated exponentially. Due to the intrinsic structural complexity in human body, electromagnetic waves show a profound variation during propagation through it. The reflection and transmission coefficients of human body are highly dependent upon the dielectric constants as well as upon the frequency. The difference in structural materials such as fat, muscles and blood essentially makes electromagnetic wave attenuation to be different along the way. Thus, a complete characterization of body channel is a challenging task. The connection between attenuation and frequency of the signal makes the investigation of UWB in WBAN an interesting proposition. In this paper, we study analytically the impact of body channels on electromagnetic signal propagation with reference to UWB. In the process, scattering, reflectivity and transmitivity have been addressed with analysis of approximate layer-wise modeling, and with numerical depictions. Pulses with Gaussian profile have been employed in our analysis. It shows that, under reasonable practical approximations, the human body channel can be modeled in layers so as to have the effects of total reflections or total transmissions in certain frequency bands. This could help decide such design issues as antenna characteristics of implant devices for WBAN employing UWB.

This study was designed to investigate the precipitation of a lipophilic drug following dispersion of lipid formulations in water. The model drug fenofibrate was formulated in representative lipid delivery systems designed for oral administration, using medium chain glycerides, polysorbates, and propylene glycol as excipients. Aqueous dispersion of water-insoluble self-emulsifying lipid formulations resulted in turbid emulsions, followed subsequently by very slow precipitation of 3-7% of the dose of fenofibrate. Self-emulsifying formulations that included water-soluble surfactants, which dissolved a lower mass of drug in solution at equilibrium, nevertheless typically maintained drugs in a metastable state, following dilution with water, for several hours or even days. Formulations with higher contents of hydrophilic materials resulted in more rapid precipitation. Extensive precipitation of fenofibrate from oil-free formulations, comprising of only surfactants and cosolvents, took place within 30 min. The results indicated that most of the lipid systems were supersaturated with respect to the drug on dilution, but the extent of precipitation varied significantly between formulations and was influenced by the extent of supersaturation after dilution. The study suggests that the use of hydrophilic formulations for delivery of lipophilic drugs may result in a greater extent of drug precipitation in the stomach.

Human adenocarcinomas overexpress a hypoglycosylated, tumor-associated form of the mucin-like glycoprotein MUC1 containing abnormal mono- and disaccharide antigens, such as Tn, sialyl-Tn, and TF, as well as stretches of unglycosylated protein backbone in the variable number of tandem repeats (VNTR) region. Both peptide and glycopeptide epitopes generated from the VNTR are candidates for cancer vaccines and we performed experiments to evaluate their relative potential to elicit tumor-MUC1-specific immunity. We show here that immunization with the 100 amino acid-long VNTR peptide (MUC1p) elicits weaker responses in MUC1 transgenic mice compared to wild type mice suggesting self-tolerance. In contrast, when glycosylated with tumor-associated Tn antigen (GalNAc-O-S/T), TnMUC1 induces glycopeptide-specific T cell and antibody responses in both strains of mice and helps enhance responses to MUC1p in MUC1 transgenic mice. Using newly derived MUC1-specific mouse T cell hybridomas we show that the only antigen-presenting cells able to cross-present TnMUC1 glycopeptide are dendritic cells (DCs). This is likely due to their exclusive expression of receptors capable of binding TnMUC1. We conclude that MUC1 glycopeptides induce stronger immunity in MUC1-Tg mice because they are recognized as 'foreign' rather than ;self' and because they are cross-presented preferentially by DCs.

The purpose of this paper is to establish single-participant white matter atlases based on diffusion tensor imaging. As one of the applications of the atlas, automated brain segmentation was performed and the accuracy was measured using Large Deformation Diffeomorphic Metric Mapping (LDDMM). High-quality diffusion tensor imaging (DTI) data from a single-participant were B0-distortion-corrected and transformed to the ICBM-152 atlas or to Talairach coordinates. The deep white matter structures, which have been previously well documented and clearly identified by DTI, were manually segmented. The superficial white matter areas beneath the cortex were defined, based on a population-averaged white matter probability map. The white matter was parcellated into 176 regions based on the anatomical labeling in the ICBM-DTI-81 atlas. The automated parcellation was achieved by warping this parcellation map to normal controls and to Alzheimer's disease patients with severe anatomical atrophy. The parcellation accuracy was measured by a kappa analysis between the automated and manual parcellation at 11 anatomical regions. The kappa values were 0.70 for both normal controls and patients while the inter-rater reproducibility was 0.81 (controls) and 0.82 (patients), suggesting "almost perfect" agreement. A power analysis suggested that the proposed method is suitable for detecting FA and size abnormalities of the white matter in clinical studies.

Ligands of CCR5, the major coreceptor of HIV-1, costimulate T lymphocyte activation. However, the full impact of CCR5 expression on T cell responses remains unknown. Here, we show that compared with CCR5(+/+), T cells from CCR5(-/-) mice secrete lower amounts of IL-2, and a similar phenotype is observed in humans who lack CCR5 expression (CCR5-Delta32/Delta32 homozygotes) as well as after Ab-mediated blockade of CCR5 in human T cells genetically intact for CCR5 expression. Conversely, overexpression of CCR5 in human T cells results in enhanced IL-2 production. CCR5 surface levels correlate positively with IL-2 protein and mRNA abundance, suggesting that CCR5 affects IL-2 gene regulation. Signaling via CCR5 resulted in NFAT transactivation in T cells that was blocked by Abs against CCR5 agonists, suggesting a link between CCR5 and downstream pathways that influence IL-2 expression. Furthermore, murine T cells lacking CCR5 had reduced levels of intranuclear NFAT following activation. Accordingly, CCR5 expression also promoted IL-2-dependent events, including CD25 expression, STAT5 phosphorylation, and T cell proliferation. We therefore suggest that by influencing a NFAT-mediated pathway that regulates IL-2 production and IL-2-dependent events, CCR5 may play a critical role in T cell responses. In accord with our prior inferences from genetic-epidemiologic studies, such CCR5-dependent responses might constitute a viral entry-independent mechanism by which CCR5 may influence HIV-AIDS pathogenesis.

There is increasing evidence indicating the roles of aldosterone and mineralocorticoid receptor (MR) in the pathogenesis of renal injury. In rats, chronic treatment with aldosterone and salt results in severe proteinuria and renal tissue injury, characterized by glomerulosclerosis and tubulointerstitial fibrosis. Aldosterone-induced renal tissue injury is associated with increases in reactive oxygen species (ROS) levels and activation of mitogen-activated protein kinases (MAPKs) or Rho-kinase. Treatment with a selective MR antagonist, eplerenone, prevents aldosterone-induced increases in ROS levels and MAPK activity and ameliorates renal injury. In vitro studies have revealed that MR is highly expressed in glomerular mesangial cells (RMCs), podocytes, and renal interstitial fibroblasts. In these renal cells, aldosterone induces cellular injury through NADPH oxidase-dependent ROS production and activation of MAPKs or Rho-kinase. Such aldosterone-induced renal cellular injury is markedly attenuated by treatment with eplerenone. These data suggest that aldosterone induces renal injury via activation of MR through mechanisms that cannot be simply explained by changes in blood pressure. In this review, we summarized recent findings on the roles of aldosterone and MR in the pathogenesis of renal injury with particular emphasis on potential underlying mechanisms.

Structural delineation and assignment are the fundamental steps in understanding the anatomy of the human brain. The white matter has been structurally defined in the past only at its core regions (deep white matter). However, the most peripheral white matter areas, which are interleaved between the cortex and the deep white matter, have lacked clear anatomical definitions and parcellations. We used axonal fiber alignment information from diffusion tensor imaging (DTI) to delineate the peripheral white matter, and investigated its relationship with the cortex and the deep white matter. Using DTI data from 81 healthy subjects, we identified nine common, blade-like anatomical regions, which were further parcellated into 21 subregions based on the cortical anatomy. Four short association fiber tracts connecting adjacent gyri (U-fibers) were also identified reproducibly among the healthy population. We anticipate that this atlas will be useful resource for atlas-based white matter anatomical studies.

Brain registration to a stereotaxic atlas is an effective way to report anatomic locations of interest and to perform anatomic quantification. However, existing stereotaxic atlases lack comprehensive coordinate information about white matter structures. In this paper, white matter-specific atlases in stereotaxic coordinates are introduced. As a reference template, the widely used ICBM-152 was used. The atlas contains fiber orientation maps and hand-segmented white matter parcellation maps based on diffusion tensor imaging (DTI). Registration accuracy by linear and non-linear transformation was measured, and automated template-based white matter parcellation was tested. The results showed a high correlation between the manual ROI-based and the automated approaches for normal adult populations. The atlases are freely available and believed to be a useful resource as a target template and for automated parcellation methods.

The tensile behavior of single-walled nanotubes (SWNTs) having two defects (vacancy or Stone-Wales) positioned next to each other was simulated in this study to investigate the influence of the spatial arrangement of defects on the mechanical properties. The simulations were performed using classical molecular dynamics (MD) at the atomic scale. Two neighboring vacancy defects reduced the failure strength as much as 46% and the failure strain as much as 80% in comparison with those of pristine SWNTs, while two neighboring Stone-Wales defects reduced them as much as 34% and 70% respectively. SWNTs having two defects in the loading (axial) direction showed higher failure strength than SWNTs with defects perpendicular to the loading direction. For both types of defect, the closer the defects, the weaker the SWNTs. As result, the defect arrangement in the SWNT structure must be one of the key factors in determining its mechanical properties, as well as the population of defects.

Formalinized Aeromonas (A.) hydrophila agglutinated loosely with the formalinized American channel catfish erythrocytes (FACCE), while live A. hydrophila agglutinated tightly with the FACCE. There was a significant difference on the number of attaching bacterial cells to the FACCE (p<0.01) (n=40 erythrocytes) between formalinized and live A. hydrophila. The other bacteria such as Salmonella (S.) Typhimurium ST-5, Escherichia (E.) coli V-517 and Staphylococcus (S.) hyicus ATCC1249 used in this experiment did not attach the FACCE.

Background/aims: The aim of this study was to determine the consistency of neuropsychiatric subsyndromes of the Neuropsychiatric Inventory across several clinical and demographic subgroups (e.g. dementia subtypes, dementia severity, medication use, age and gender) in a large sample of outpatients with dementia., Methods: Cross-sectional data of 2,808 patients with dementia from 12 centres from the European Alzheimer's Disease Consortium were collected. Principal component analysis was used for factor analysis. Subanalyses were performed for dementia subtypes, dementia severity, medication use, age and gender., Results: The results showed the relatively consistent presence of the 4 neuropsychiatric subsyndromes 'hyperactivity', 'psychosis', 'affective symptoms' and 'apathy' across the subanalyses. The factor structure was not dependent on dementia subtypes, age and gender but was dependent on dementia severity and cholinesterase use. The factors hyperactivity and affective symptoms were present in all subanalyses, but the presence of the factors apathy and psychosis was dependent on use of cholinesterase inhibitors and dementia severity, respectively., Conclusion: The present study provided evidence of the relative consistency of neuropsychiatric subsyndromes across dementia subtypes, age and gender, thereby stressing the importance of thinking about neuropsychiatric subsyndromes instead of separate symptoms. However, the subsyndromes apathy and psychosis were dependent on use of cholinesterase inhibitors and dementia severity., ((c) 2007 S. Karger AG, Basel.)

Objectives: We describe the antimicrobial activity against Pseudomonas aeruginosa of the de novo-derived antimicrobial peptide WLBU2 in an animal model of infection., Methods: For this study, an intravenous (iv) model of P. aeruginosa infection was established. The minimum lethal murine dose of P. aeruginosa strain PA01 was determined to be 3 x 10(7) cfu when bacteria were administered iv. Increasing concentrations of WLBU2 were instilled either prior to or following PA01 septic exposure., Results: For the mice given peptide post-bacterial infection, in the 1 mg/kg group, nine of nine animals died because of Pseudomonas sepsis; in the 3 mg/kg group, only one of nine succumbed to infection and in the 4 mg/kg group, all mice were protected (P < 0.0001). Similar results were obtained when WLBU2 was given 1 h prior to Pseudomonas infection., Conclusions: Although the therapeutic window in this model is narrow, the results nonetheless provide encouraging evidence for WLBU2 as a potential prophylactic or treatment of bacterial infection.

We conducted a seroprevalence study and exposure survey of healthcare workers to assess the risk of nosocomial transmission of Nipah virus during an outbreak in Bangladesh in 2004. No evidence of recent Nipah virus infection was detected despite substantial exposures and minimal use of personal protective equipment.

Screening, Brief Intervention, and Referral to Treatment (SBIRT) is a comprehensive and integrated approach to the delivery of early intervention and treatment services through universal screening for persons with substance use disorders and those at risk. This paper describes research on the components of SBIRT conducted during the past 25 years, including the development of screening tests, clinical trials of brief interventions and implementation research. Beginning in the 1980s, concerted efforts were made in the US and at the World Health Organization to provide an evidence base for alcohol screening and brief intervention in primary health care settings. With the development of reliable and accurate screening tests for alcohol, more than a hundred clinical trials were conducted to evaluate the efficacy and cost effectiveness of alcohol screening and brief intervention in primary care, emergency departments and trauma centers. With the accumulation of positive evidence, implementation research on alcohol SBI was begun in the 1990s, followed by trials of similar methods for other substances (e.g., illicit drugs, tobacco, prescription drugs) and by national demonstration programs in the US and other countries. The results of these efforts demonstrate the cumulative benefit of translational research on health care delivery systems and substance abuse policy. That SBIRT yields short-term improvements in individuals' health is irrefutable; long-term effects on population health have not yet been demonstrated, but simulation models suggest that the benefits could be substantial.

Background/aims: The aim of this study was to identify neuropsychiatric subsyndromes of the Neuropsychiatric Inventory in a large sample of outpatients with Alzheimer's disease (AD)., Methods: Cross-sectional data of 2,354 patients with AD from 12 centres from the European Alzheimer's Disease Consortium were collected. Principal component analysis was used for factor analysis., Results: The results showed the presence of 4 neuropsychiatric subsyndromes: hyperactivity, psychosis, affective symptoms and apathy. The subsyndrome apathy was the most common, occurring in almost 65% of the patients., Conclusion: This large study has provided additional robust evidence for the existence of neuropsychiatric subsyndromes in AD., ((c) 2007 S. Karger AG, Basel.)

We report a 62-year-old lady who presented with abdominal lump and neurological deficit. Investigations showed ascending colon mass, subcutaneous nodule and right parietal lobe lesion. Histology and immunohistochemistry were suggestive of malignant melanoma. The search for primary site was negative.

Hybrid nanostructures consisting of tungsten oxide nanorods with mushroom-shaped carbon caps were grown on electrochemically etched tungsten tips by thermal chemical vapor deposition with methane and argon. These nanorods grow along the radial direction and are very straight and smooth. Electron microscopy revealed a dominant diameter and length of approximately 50 nm and approximately 0.6 microm, respectively. High-resolution transmission electron microscopy (HRTEM), and electron energy loss spectroscopy (EELS) revealed the presence of crystalline monoclinic W18O49 in the nanorods, and the cap was entirely amorphous carbon. A plausible growth mechanism involves the reduction of tungsten oxide WO3, present on the tungsten surface, by methane at 900 degrees C.

The performance of capillary electrophoresis-ultraviolet detector (CE-UV), hydride generation-atomic absorption spectrometry (HG-AAS) and liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS) have been compared for the speciation of arsenic (As) in groundwater samples. Two inorganic As species, arsenite (As(III)), arsenate (As(V)) and one organo species dimethyl arsenic acid (DMA) were mainly considered for this study as these are known to be predominant in water. Under optimal analytical conditions, limits of detection (LD) ranging from 0.10 (As(III), AsT) to 0.19 (DMA) mug/l for HG-AAS, 100 (As(III), DMA) to 500 (As(V)) mug/l for CE-UV and 0.1 (DMA, MMA) to 0.2 (As(III), As(V)) mug/l for LC-ICP-MS, allowed the determination of the above three species present in these samples. Results obtained by all the three methods are well correlated (r(2)=0.996*** for total As) with the precision of <5% R.S.D. except CE-UV. The effect of interfering ions (e.g. Fe(2+), Fe(3+), SO(4)(2-) and Cl(-)) commonly found in ground water on separation and estimation of As species were studied and corrected for. Spike recovery was tested and found to be 80-110% at 0.5mug/l As standard except CE-UV where only 50% of the analyte was recovered. Comparison of these results shows that LC-ICP-MS is the best choice for routine analysis of As species in ground water samples.

Cationic amphipathic peptides have been extensively investigated as a potential source of new antimicrobials that can complement current antibiotic regimens in the face of emerging drug-resistant bacteria. However, the suppression of antimicrobial activity under certain biologically relevant conditions (e.g., serum and physiological salt concentrations) has hampered efforts to develop safe and effective antimicrobial peptides for clinical use. We have analyzed the activity and selectivity of the human peptide LL37 and the de novo engineered antimicrobial peptide WLBU2 in several biologically relevant conditions. The host-derived synthetic peptide LL37 displayed high activity against Pseudomonas aeruginosa but demonstrated staphylococcus-specific sensitivity to NaCl concentrations varying from 50 to 300 mM. Moreover, LL37 potency was variably suppressed in the presence of 1 to 6 mM Mg(2+) and Ca(2+) ions. In contrast, WLBU2 maintained its activity in NaCl and physiologic serum concentrations of Mg(2+) and Ca(2+). WLBU2 is able to kill P. aeruginosa (10(6) CFU/ml) in human serum, with a minimum bactericidal concentration of <9 microM. Conversely, LL37 is inactive in the presence of human serum. Bacterial killing kinetic assays in serum revealed that WLBU2 achieved complete bacterial killing in 20 min. Consistent with these results was the ability of WLBU2 (15 to 20 microM) to eradicate bacteria from ex vivo samples of whole blood. The selectivity of WLBU2 was further demonstrated by its ability to specifically eliminate P. aeruginosa in coculture with human monocytes or skin fibroblasts without detectable adverse effects to the host cells. Finally, WLBU2 displayed potent efficacy against P. aeruginosa in an intraperitoneal infection model using female Swiss Webster mice. These results establish a potential application of WLBU2 in the treatment of bacterial sepsis.

Comparison of human immunodeficiency virus lentiviral lytic peptide 1 with other host-derived peptides indicates that antimicrobial properties of membrane-active peptides are markedly influenced by their cationic, hydrophobic, and amphipathic properties. Many common themes, such as Arg composition of the cationic face of an amphipathic helix and the importance of maintaining the hydrophobic face, have been deduced from these observations. These studies suggest that a peptide with these structural properties can be derived de novo by using only a few strategically positioned amino acids. However, the effects of length and helicity on antimicrobial activity and selectivity have not been objectively evaluated in the context of this motif. To address these structure-function issues, multimers of a 12-residue lytic base unit (LBU) peptide composed only of Arg and Val residues aligned to form idealized amphipathic helices were designed. Bacterial killing assays and circular dichroism analyses reveal a strong correlation between antibacterial activity, peptide length, and propensity to form a helix in solvent mimicking the environment of a membrane. Increasing peptide length beyond two LBUs (24-residue peptides) resulted in no appreciable increase in antimicrobial activity. Derivatives (WLBU) of the LBU series were further engineered by substituting Trp residues in the hydrophobic domains. The 24-residue WLBU2 peptide was active at physiologic NaCl concentrations against Staphylococcus aureus and mucoid and nonmucoid strains of Pseudomonas aeruginosa. Further, WLBU2 displayed the highest antibacterial selectivity of all peptides evaluated in the present study by using a coculture model of P. aeruginosa and primary human skin fibroblasts. These findings provide fundamental information toward the de novo design of an antimicrobial peptide useful for the management of infectious diseases.

This descriptive cross-sectional study was conducted to investigate gender differences in the epidemiological factors associated with the treatment seeking behaviors of TB cases in the rural communities of Bangladesh. The study reveals that there is significant gender difference in treatment seeking behaviors of rural TB cases and the majority of them (52%) have taken prior treatment from various traditional healers, 70% of them are females who attended health centers (UZHCs) as the other choice (adjusted OR: 4.2, 95% CI: 2.0-8.4). It was found that the mean patient delay was 63 days (range 14-210 days) where half of the females delayed more than 60 days while they were spreading their disease. The study findings reveal gender differences in treatment seeking behaviors associated with socio-cultural barriers, particularly among females in their access to TB care. Fifty-five percent of cases wanted the diagnosis of TB remain confidential to avoid being labeled as TB patients, where 82.7% were female, 85.6% of female TB patients had problems in their relationships with their spouse (61%) and family members (58%) after being diagnosed with TB. The results of the TB service factors found that 39% of females were not satisfied with their provider's behaviors, which was significantly associated with treatment seeking behavior (adjusted OR: 2.6, 95% CI: 1.0-6.6). The study findings strongly suggest that there was a significant gender difference in treatment seeking behavior in rural Bangladesh. Based on the study findings, we recommend developing an appropriate gender strategy for developing a TB control program, comprised of operational, socio-cultural and community awareness interventions aimed at treating undiscovered reservoirs of female TB cases in rural Bangladesh.

Lentivirus lytic peptides (LLPs) are derived from HIV-1 and have antibacterial properties. LLP derivatives (eLLPs) were engineered for greater potency against Staphylococcus aureus (SA) and Pseudomonas aeruginosa (PA). Minimum bactericidal concentration (MBC) was determined in low and physiologic salt concentrations. MBC was decreased against SA and equivalent against PA in physiologic salt when compared to the parent compound LLP1. In a novel cystic fibrosis (CF) airway cell model, one derivative, WLSA5, reduced the number of adherent PA and only moderately affected CF cell viability. Overall, eLLPs are selectively toxic to bacteria and may be useful against CF airway infections.

The aim of the present study was to investigate the nutritional status of drug addicts, the prevalence of malnutrition among them and the influence of their drug habit and lifestyle factors on their nutritional indices. The study was conducted among 253 male drug addicts, who sought detoxification at the Central Drug Addiction Treatment Hospital, Dhaka, during the period of June 1998-July 1999. One hundred age-, height- and socioeconomic-matched non-addicted healthy men were recruited by convenience as cohort controls. Results showed that the drug addicts had significantly (P<0.001) lowered BMI, haemoglobin, and serum total protein and albumin levels. Clinical signs of nutrient deficiency were diagnosed in about 74 % of drug addicts. The BMI, biochemical values and nutrient deficiency signs indicated that more than 60 % of drug addicts were suffering from multiple malnutrition. One-way ANOVA demonstrated a significant (P<0.05) negative correlation between drug habit, sexually transmitted diseases and selected nutritional indices, and a positive correlation between education, income and the nutritional indices. A series of multiple regression analyses revealed that education, income and age showed significantly predicted BMI and biochemical indices, and the group (non-drug addicts or drug addicts) had a significant negative effect on these parameters in favour of controls.

Bis-lentivirus lytic protein 1 (Bis-LLP1) and polymyxin B exhibited similar killing activities against Serratia marcescens. By electron microscopy, bis-LLP1 interacted with the outer and cytoplasmic bacterial membranes, while polymyxin B affected only the outer membrane. The results of standard biochemical probes supported the findings of the electron microscopy studies, suggesting that these antimicrobial peptides have different mechanisms of action.

A synthesis of heliannuol A 1 is described involving hydrogenolysis of the cyclopropane fused benzoxepane compound 23 to generate the benzoxocane ring system of 1 and a fragmentation of methyl ether 25 furnished 4-methoxycurcuphenol 29, an advanced intermediate to heliannuol D 4.

The microbiological safety, refrigeration shelf-life, and nutritional quality of chicken breast meat were investigated following combined electron-beam irradiation and cooking under vacuum (sous-vide). Chicken breast meat inoculated with 10 6 CFU/g of Listeria monocytogenes was irradiated with an electron beam at doses up to 3.1 kGy under vacuum in barrier bags, cooked in a boiling water bath for 3 min 45 s (previously determined to achieve an internal temperature of 71.1°C), and stored at 8°C for up to 5 weeks. Listeria was undetectable in samples treated with combined sous-vide and irradiation at 3.1 kGy, but the organism survived the sous-vide treatment without irradiation and multiplied during storage. A similar study, conducted with uninoculated chicken breast meat, revealed that the product which received both irradiation (3 kGy) and sous-vide treatment had a shelf-life of at least 8 weeks at 8°C, whereas the unirradiated samples treated sous-vide spoiled in 16 days. Listeria was undetectable in combination treated samples, but some of the unirradiated sous-vide samples tested after long storage showed high levels of Listeria . Some loss of thiamine occurred with the combined treatments.

The influence of suspension in a phosphate buffer and various lipid media on the heat and radiation resistance of Clostridium sporogenes PA3679 was examined. Lyophilized spores were suspended in vegetable oils, animal fats, synthetic triglycerides, glycerol, or phosphate buffer, and their radiation and heat D ]0 values (dose or time required for 90% inactivation) were determined. Radiation D 10 values in the lipids were much higher than in the phosphate buffer. Radiation D 10 values in glycerol and animal fats were higher than in the vegetable oils and the synthetic triglycerides. The D 10 values in triolein and tributyrin were close to each other, suggesting that chain length may not be a significant factor in radiation resistance. The heat D 10 value of the spores in a phosphate buffer at 95 ± 1°C was close to that in beef fat and was much higher than in any of the other lipid media tested. The heat D 10 value in triolein was greater than twice that in tributyrin, suggesting that the fatty acid chain length is an important factor in the heat resistance of the spores in triglycerides. The effects of various nonaqueous suspension media on the radiation-induced thermosensitivity of spores were also determined. A comparison of the heat D 10 values of the spores with and without prior irradiation in various media showed that irradiation at 5.0 kGy greatly increased their heat sensitivity.

Radiobiological studies were carried out with three strains of Listeria monocytogenes . Resistance characteristics were determined under a variety of conditions. For one strain (CFPDC), the D 10 values were 0.18, 0.21, and 0.44 kGy when subjected to gamma irradiation in phosphate buffer (pH 7.0), trypticase soy broth containing yeast extract (TSB-YE), and in poultry feed, respectively. For this strain, D 10 values in poultry feed determined by using 60 Co gamma rays or 10 MeV electrons as radiation sources were almost identical. D values for gamma irradiation of TSB-YE cultures were 0.21, 0.25, and 0.46 kGy for CFPDC, Scott A, and 81-861 strains, respectively.