Assessment of trans-cinnamaldehyde and eugenol assisted heat treatment against Salmonella Typhimurium in low moisture food components

Increased thermal resistance of Salmonella at low water activity (a_w) is a significant food safety concern in low-moisture foods (LMFs). We evaluated whether trans-cinnamaldehyde (CA, 1000 ppm) and eugenol (EG, 1000 ppm), which can accelerate thermal inactivation of Salmonella Typhimurium in water, can show similar effect in bacteria adapted to low a_w in different LMF components. Although CA and EG significantly accelerated thermal inactivation (55 °C) of S. Typhimurium in whey protein (WP), corn starch (CS) and peanut oil (PO) at 0.9 a_w, such effect was not observed in bacteria adapted to lower a_w (0.4). The matrix effect on bacterial thermal resistance was observed at 0.9 a_w, which was ranked as WP > PO > CS. The effect of heat treatment with CA or EG on bacterial metabolic activity was also partially dependent on the food matrix. Bacteria adapted to lower a_w had lower membrane fluidity and unsaturated to saturated fatty acids ratio, suggesting that bacteria at low a_w can change its membrane composition to increase its rigidity, thus increasing resistance against the combined treatments. This study demonstrates the effect of a_w and food components on the antimicrobials-assisted heat treatment in LMF and provides an insight into the resistance mechanism.

The genetic response of Salmonella Typhimurium during trans-cinnamaldehyde assisted heat treatment and its correlation with bacterial resistance in different low moisture food components

Our previous study found that water activity (a_w)- and matrix-dependent bacterial resistance wasdeveloped in Salmonella Typhimurium during antimicrobial-assisted heat treatment in low moisture foods (LMFs) matrices. To better understand the molecular mechanism behind the observed bacterial resistance, gene expression analysis was conducted on S. Typhimurium adapted to different conditions with or without the trans-cinnamaldehyde (CA)-assisted heat treatment via quantitative polymerase chain reaction (qPCR). Expression profiles of nine stress-related genes were analyzed. The upregulation of rpoH and dnaK and downregulation of ompC were observed during bacterial adaptation in LMF matrices and the combined heat treatment, which likely contributed to the bacterial resistance during the combined treatment. Their expression profiles were partially consistent with the previously-observed effect of a_w or matrix on bacterial resistance. The upregulation of rpoE, otsB, proV, and fadA was also observed during adaptation in LMF matrices and might contribute to desiccation resistance, but likely did not contribute to bacterial resistance during the combined heat treatment. The observed upregulation of fabA and downregulation of ibpA could not be directly linked to bacterial resistance to either desiccation or the combined heat treatment. The results may assist the development of more efficient processing methods against S. Typhimurium in LMFs.

Evaluation of multiplex nanopore sequencing for Salmonella serotype prediction and antimicrobial resistance gene and virulence gene detection

In a previous study, Multiplex-nanopore-sequencing based whole genome sequencing (WGS) allowed for accurate in silico serotype prediction of Salmonella within one day for five multiplexed isolates, using both SISTR and SeqSero2. Since only ten serotypes were tested in our previous study, the conclusions above were yet to be evaluated in a larger scale test. In the current study we evaluated this workflow with 69 Salmonella serotypes and also explored the feasibility of using multiplex-nanopore-sequencing based WGS for antimicrobial resistance gene (AMR) and virulence gene detection. We found that accurate in silico serotype prediction with nanopore-WGS data was achieved within about five hours of sequencing at a minimum of 30× Salmonella genome coverage, with SeqSero2 as the serotype prediction tool. For each tested isolate, small variations were observed between the AMR/virulence gene profiles from the Illumina and Nanopore sequencing platforms. Taking results generated using Illumina data as the benchmark, the average precision value per isolate was 0.99 for both AMR and virulence gene detection. We found that the resistance gene identifier - RGI identified AMR genes with nanopore data at a much lower accuracy compared to Abricate, possibly due to RGI's less stringent minimum similarity and coverage by default for database matching. This study is an evaluation of multiplex-nanopore-sequencing based WGS as a cost-efficient and rapid Salmonella classification method, and a starting point for future validation and verification of using it as a AMR/virulence gene profiling tool for the food industry. This study paves the way for the application of nanopore sequencing in surveillance, tracking, and risk assessment of Salmonella across the food supply chain.

Enhancement of Thermal Inactivation of Cronobacter sakazakii in Apple Juice at 58°C by Inclusion of Butyl Para-Hydroxybenzoate and Malic Acid

ABSTRACT

After studies with powdered infant formula indicated that the enhancement of thermal inactivation of Cronobacter sakazakii by butyl para-hydroxybenzoate (BPB) was blocked by high protein concentrations, we hypothesized that BPB would retain its synergistic activity in foods with limited protein and lipid concentrations. This hypothesis was tested by examining the ability of BPB to enhance the thermal inactivation of C. sakazakii 607 at 58°C in commercial apple juice, including examining the effects of pH and possible synergistic effects with malic acid. Apple juice was adjusted to designated pH values of 3.2 to 9.0, supplemented with selected concentrations of BPB (≤125 ppm), inoculated with early-stationary-phase C. sakazakii 607, and thermally treated (58°C) for 15 min with a submerged coil apparatus. The same methods were used to study the enhancement of thermal inactivation by malic acid. Samples were plated on tryptic soy agar for recovery and enumeration. Survival curves were plotted, and D-values were calculated by linear regression and compared using the Tukey honestly significant difference test. BPB significantly enhanced thermal inactivation in a concentration dependent manner, with D-values of a few seconds at the original pH (3.8). The enhancement of thermal inactivation was pH dependent over the pH range of 3.4 to 9.0. Malic acid enhanced thermal inactivation; the pH was decreased from 3.8 to 3.2. These results support the hypothesis that BPB can enhance the thermal inactivation of C. sakazakii in low-protein and low-lipid foods.

HIGHLIGHTS

Evaluation of Potential for Butyl and Heptyl Para-Hydroxybenzoate Enhancement of Thermal Inactivation of Cronobacter sakazakii during Rehydration of Powdered Infant Formula and Nonfat Dry Milk

ABSTRACT

In previous studies, parabens in model systems enhanced the thermal inactivation of foodborne pathogens, including Cronobacter sakazakii, Salmonella enterica serotype Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes. However, few studies have been conducted to evaluate this phenomenon in actual food systems. In the present study, the potential enhancement of thermal inactivation of C. sakazakii by butyl para-hydroxybenzoate (BPB) was evaluated in powdered infant formula (PIF) and nonfat dry milk (NFDM) in dry and rehydrated forms. When PIF was rehydrated with water at designated temperatures (65 to 80°C) in baby bottles, BPB did not enhance thermal inactivation. When rehydrated NFDM and lactose solutions with BPB were inoculated and heated at 58°C, BPB enhancement of thermal inactivation of C. sakazakii was negatively associated with the concentration of NFDM solutions in a dose-dependent manner, whereas thermal inactivation was enhanced in the presence of lactose regardless of its concentration, suggesting an interaction between proteins and BPB. Fluorescence testing further indicated an interaction between BPB and the proteins in PIF and NFDM. In inoculated dry NFDM with and without BPB stored at 24 and 55°C for 14 days, BPB did not substantially enhance bacterial inactivation. This study suggests that BPB is not likely to enhance mild thermal bacterial inactivation treatments in foods that have appreciable amounts of protein.

HIGHLIGHTS

Summary of the AOAC-Sponsored Workshop Series Related to the Global Understanding of Food Fraud (GUFF): Mobilization of Resources for Food Authenticity Assurance and Food Fraud Prevention and Mitigation

BACKGROUND

Reports of incidents associated with the misrepresentation of food products as well as the adulteration of their composition leading, at times, to significant public health impacts are being recorded.

OBJECTIVE

This paper aims at summarizing the outputs of three workshops dedicated to the theme "Global Understanding of Food Fraud" (GUFF), held in Quebec City in Canada (April 2017), Beijing in the People's Republic of China (October 2017) and Dubai in the United Arab Emirates (October 2018).

METHOD

Based on the contributions made at these workshops, the paper reviews current knowledge related to food fraud shared by experts and stakeholders representing the food industry sector, food regulators both domestically and internationally and scientists from Academia. It also discusses approaches available to the industry across the food supply chain to predict, prevent, and possibly mitigate food fraud, inclusive of targeted and non-targeted methods of analysis.

RESULTS AND CONCLUSIONS

The paper offers a discussion on areas warranting the mobilization of efforts and resources of the food stakeholder community to reach consistent and accessible guidance on food fraud prevention, validated analytical methods along with an increased emphasis on prevention in food regulatory measures targeting food fraud. Further development is needed to reach consistent and accessible guidance on food fraud prevention, validated analytical methods, along with an emphasis on food fraud prevention.

HIGHLIGHTS

Food fraud is receiving increased attention from consumers, regulators, and industry. International food fraud experts were invited to three workshops. Contributions and conclusions from the workshops are reported and discussed.

Assessment of butylparaben (4-hydroxybenzoic acid butyl ester)-assisted heat treatment against Escherichia coli O157:H7 and Salmonella enterica serotype Typhimurium in meat and bone meal

Heat-resistant foodborne pathogens have been a concern in low-moisture foods and ingredients (LMFs). Due to low thermal conductivity of low moisture materials, thermal treatment is not efficient and may cause nutritional loss. This study investigated the enhancement of thermal treatment of meat and bone meal (MBM) at low water activity (a_w ) by inclusion of butylparaben (BP) as a model antimicrobial compound. Stationary phase Escherichia coli O157:H7 (Shiga toxin-negative) or Salmonella enterica serotype Typhimurium was inoculated into MBM containing 0-2000 ppm BP and incubated at 55 or 60°C for up to 5 hr. A biphasic inactivation pattern was observed for both pathogens, indicating existence of potentially thermal resistant subpopulations. Addition of 1000 ppm BP to MBM (a_w  = 0.4) significantly lowered the D-value at 55°C for E. coli O157:H7 (2.6 ± 0.5 hr) compared to thermal treatment alone (5.1 ± 0.6 h) during the treatment after the first 1 hr (p < 0.05), indicating that addition of BP accelerated the inactivation of thermal-resistant subpopulation of E. coli O157:H7 in MBM. Interestingly, similar enhancement in thermal inactivation upon addition of BP was not observed in either the sensitive or resistant subpopulation of S. Typhimurium at a_w of 0.4 or 0.7, which is likely caused by the higher thermal resistance developed by S. Typhimurium within a low a_w environment (a_w  < 0.85). These results suggest that addition of certain antimicrobial compounds can improve the thermal processing efficiency in LMFs, while their efficiency against different pathogens may vary. PRACTICAL APPLICATION: Addition of appropriate food-grade compounds may help to improve thermal treatment efficiency in low moisture foods with varied efficiency against different pathogens. This approach has the potential to reduce the required heat treatment intensity while minimizing food safety risk.

Synergistic Effects of Butyl Para-Hydroxybenzoate and Mild Heating on Foodborne Pathogenic Bacteria

ABSTRACT

Although high-temperature heat treatments can efficiently reduce pathogen levels, they also affect the quality and nutritional profile of foods and increase the cost of processing. The food additive butyl para-hydroxybenzoate (BPB) was investigated for its potential to synergistically enhance thermal microbial inactivation at mild heating temperatures (54 to 58°C). Four foodborne pathogenic bacteria, Cronobacter sakazakii, Salmonella enterica Typhimurium, attenuated Escherichia coli O157:H7, and Listeria monocytogenes, were cultured to early stationary phase and then subjected to mild heating at 58, 55, 57, and 54°C, respectively, in a model food matrix (brain heart infusion [BHI]) containing low concentrations of BPB (≤125 ppm). The temperature used with each bacterium was selected based on the temperature that would yield an approximately 1- to 3-log reduction over 15 min of heating in BHI without BPB in a submerged coil system. The inclusion of BPB at ≤125 ppm resulted in significant enhancement of thermal inactivation, achieving 5- to >6-log reductions of the gram-negative strains with D-values of <100 s. A 3- to 4-log reduction of L. monocytogenes was achieved with a similar treatment. No significant microbial inactivation was noted in the absence of mild heating for the same time period. This study provides additional proof of concept that low-temperature inactivation of foodborne pathogens can be realized by synergistic enhancement of thermal inactivation by additives that affect microbial cell membranes.

HIGHLIGHTS

Evaluation of nanopore sequencing technology to identify Salmonella enterica Choleraesuis var. Kunzendorf and Orion var. 15+, 34. Int J Food Microbiol 2021;346:109167. [PMID: 33774575 DOI: 10.1016/j.ijfoodmicro.2021.109167]

Our previous study demonstrated that whole genome sequencing (WGS) data generated by Oxford Nanopore Technologies (ONT) can be used for rapid and accurate prediction of selected Salmonella serotypes. However, one limitation is that established methods for WGS-based serotype prediction, utilizing data from either ONT or Illumina, cannot differentiate certain serotypes and serotype variants with the same or closely related antigenic formulae. This study aimed to evaluate nanopore sequencing and additional data analysis for identification of Salmonella enterica Choleraesuis var. Kunzendorf and S. enterica Orion var. 15⁺, 34⁺, thus overcoming this limitation. Five workflows that combined different flow cells, library construction methods and basecaller models were evaluated and compared. The workflow that consisted of the R9 flow cell, rapid sequencing library construction kit and guppy basecaller with base modified model performed best for Single Nucleotide Polymorphism (SNP) analysis. With this workflow, 99.98% of matching identity between assembled genomes from ONT and that from Illumina was achieved. Less than five high-quality SNPs differed when comparing sequencing data between ONT and Illumina. SNP typing successfully identified Choleraesuis var. Kunzendorf. While prophage prediction further differentiated Orion var. 15⁺, 34⁺ from the other two Orion variants. Our study improves the readiness of ONT as a Salmonella subtyping and source tracking tool for food industry applications.

Evaluation of Salmonella Serotype Prediction With Multiplex Nanopore Sequencing

The use of whole genome sequencing (WGS) data generated by the long-read sequencing platform Oxford Nanopore Technologies (ONT) has been shown to provide reliable results for Salmonella serotype prediction in a previous study. To further meet the needs of industry for accurate, rapid, and cost-efficient Salmonella confirmation and serotype classification, we evaluated the serotype prediction accuracy of using WGS data from multiplex ONT sequencing with three, four, five, seven, or ten Salmonella isolates (each isolate represented one Salmonella serotype) pooled in one R9.4.1 flow cell. Each multiplexing strategy was repeated with five flow cells, and the loaded samples were sequenced simultaneously in a GridION sequencer for 48 h. In silico serotype prediction was performed using both SeqSero2 (for raw reads and genome assemblies) and SISTR (for genome assemblies) software suites. An average of 10.63 Gbp of clean sequencing data was obtained per flow cell. We found that the unevenness of data yield among each multiplexed isolate was a major barrier for shortening sequencing time. Using genome assemblies, both SeqSero2 and SISTR accurately predicted all the multiplexed isolates under each multiplexing strategy when depth of genome coverage ≥50× for each isolate. We identified that cross-sample barcode assignment was a major cause of prediction errors when raw sequencing data were used for prediction. This study also demonstrated that, (i) sequence data generated by ONT multiplex sequencing can be used to simultaneously predict serotype for three to ten Salmonella isolates, (ii) with three to ten Salmonella isolates multiplexed, genome coverage at ≥50× per isolate was obtained within an average of 6 h of ONT multiplex sequencing, and (iii) with five isolates multiplexed, the cost per isolate might be reduced to 23% of that incurred with single ONT sequencing. This study is a starting point for future validation of multiplex ONT WGS as a cost-efficient and rapid Salmonella confirmation and serotype classification tool for the food industry.

Extended Enrichment Procedures Can Be Used To Define False-Negative Probabilities for Cultural Gold Standard Methods for Salmonella Detection, Facilitating Comparisons between Gold Standard and Alternative Methods

ABSTRACT

Evaluation of alternative detection methods for foodborne pathogens typically involves comparisons against a "gold standard" culture method, which may produce false-negative (FN) results, particularly under worst-case scenarios such as low contamination levels, difficult-to-detect strains, and challenging food matrices (e.g., matrices with a water activity of <0.6). We used extended enrichment times (up to 72 h for both primary and secondary enrichments) to evaluate a gold standard method for Salmonella detection (the U.S. Food and Drug Administration Bacteriological Analytical Manual [BAM] method) in two low-water-activity foods (dry pet food and chocolate) inoculated at low contamination levels (most probable number ca. 1/25 g) with five Salmonella strains. Strains were selected to include those with a poor ability to grow in enrichment media. Among the 100 pet food and 100 chocolate samples tested, 53 and 50, respectively, were positive with the standard BAM method, and 57 and 59, respectively, were positive with the extended BAM method. Thus, the FN probabilities for the standard BAM method were 7% for pet food and 15% for chocolate. An alternative enzyme immunoassay method for detection of Salmonella in chocolate produced FN probabilities of 6 and 20% when compared against the standard and extended BAM methods, respectively. Detection of Salmonella Mississippi was significantly reduced with the alternative method (P = 0.023) compared with the extended BAM method. We calculated a composite reference standard to further define FN probabilities based on variable results from multiple assays (the standard BAM, extended BAM, and alternative methods). Based on this standard, the enzyme immunoassay for Salmonella detection in chocolate had a 28% FN probability and the standard and extended BAM methods had 23 and 9% FN probabilities, respectively. These results provide a framework for how inclusion of extended enrichment times can facilitate evaluation of alternative detection methods.

HIGHLIGHTS

Interference of mycotoxin binders with ELISA, HPLC and LC-MS/MS analysis of aflatoxins in maize and maize gluten

The aim of this study was to investigate the impact of mycotoxin binders on the determination of aflatoxins in maize and maize gluten using various analytical methods, including ELISA, HPLC and LC-MS/MS. Three types of commercially available mycotoxin binders, yeast cell wall, mineral, and a mixture of mineral and bacterium, were investigated at inclusion levels of 0.1%, 0.2% and 0.4%. The binders were added to maize and maize gluten contaminated with aflatoxins at concentrations between 6.9 and 26.7 μg kg^-1. The samples were analysed and the values were compared with corresponding controls (samples without binders) using ANOVA. The yeast cell wall binder had no significant effect (p=0.05) on the concentration of aflatoxins measured in either maize or maize gluten at any of the three inclusion levels, regardless of which analytical method was used. The mineral binder and the mixed mineral and bacterium binder had no significant effect (p=0.05) on the measured aflatoxin concentrations in either maize or maize gluten at any of the three inclusion levels when analysis was conducted using LC-MS/MS. Inclusion of these binders resulted in significant lower (p<0.01) detection of aflatoxins in both maize and maize gluten when analysis was conducted using ELISA; the effect was dose-dependent. They also resulted in significant lower detection of aflatoxins in maize extracted by methanol/water (70/30 v/v) (p<0.0001) and in maize gluten extracted by acetonitrile/water (80/20 v/v) (p<0.05) when analysis was conducted using HPLC. However, neither the mineral binder nor the mixed mineral and bacterium binder had significant effects (p=0.05) on aflatoxin concentrations measured in maize using HPLC, when extracted by acetonitrile/water (80/20 v/v). The study demonstrated that mycotoxin binders could result in underestimation of the levels of aflatoxin contamination, depending on the nature of the binder, the extraction solvent used in the analytical method, and the composition of tested sample.

Assessment and Comparison of Molecular Subtyping and Characterization Methods for Salmonella

The food industry is facing a major transition regarding methods for confirmation, characterization, and subtyping of Salmonella. Whole-genome sequencing (WGS) is rapidly becoming both the method of choice and the gold standard for Salmonella subtyping; however, routine use of WGS by the food industry is often not feasible due to cost constraints or the need for rapid results. To facilitate selection of subtyping methods by the food industry, we present: (i) a comparison between classical serotyping and selected widely used molecular-based subtyping methods including pulsed-field gel electrophoresis, multilocus sequence typing, and WGS (including WGS-based serovar prediction) and (ii) a scoring system to evaluate and compare Salmonella subtyping assays. This literature-based assessment supports the superior discriminatory power of WGS for source tracking and root cause elimination in food safety incident; however, circumstances in which use of other subtyping methods may be warranted were also identified. This review provides practical guidance for the food industry and presents a starting point for further comparative evaluation of Salmonella characterization and subtyping methods.

A novel approach to improve undergraduate surgical teaching

BACKGROUND

Undergraduate surgery is at an important crossroads. Many departments report significant difficulties delivering effective teaching. Our student feedback indicated a dated surgical curriculum lacking structure, quality and uniformity. We report on a new "blended" approach employing a combination of professional DVDs, case based discussions, online material and traditional bedside teaching designed to provide structure, standardization, and equality of learning .

METHODS

Year 4 students who had undertaken the new course and year 5 students who had participated in the traditional teaching programme were compared. Students completed a 20 item questionnaire about their experiences of the surgical teaching programme.

RESULTS

One hundred and seventy-one year 4 (70%) and 148 year 5 students (66%) responded. Domains relating to "Overall Satisfaction with the course", "Approval of innovative teaching methods and interactivity" and "Satisfaction with the clarity of course information" showed improvements when comparing the new and old programmes. However bedside teaching was not rated as highly in the new programme (p<0.05).

CONCLUSION

This blended approach has resulted in improved student understanding and engagement. The apparent compromise of bedside teaching may be a reflection of higher expectations. We believe that a similar blended approach has the potential to re-invigorate surgical teaching elsewhere.

Framework for managing mycotoxin risks in the food industry

We propose a methodological framework for managing mycotoxin risks in the food processing industry. Mycotoxin contamination is a well-known threat to public health that has economic significance for the food processing industry; it is imperative to address mycotoxin risks holistically, at all points in the procurement, processing, and distribution pipeline, by tracking the relevant data, adopting best practices, and providing suitable adaptive controls. The proposed framework includes (i) an information and data repository, (ii) a collaborative infrastructure with analysis and simulation tools, (iii) standardized testing and acceptance sampling procedures, and (iv) processes that link the risk assessments and testing results to the sourcing, production, and product release steps. The implementation of suitable acceptance sampling protocols for mycotoxin testing is considered in some detail.

Abstract P6-04-22: Regulation of Notch localization by endocrine therapy in Estrogen Receptor positive breast cancer cells: Clinical implications for endocrine resistance

Background: Estrogen receptors occur in about two-thirds of breast tumors and endocrine therapy is probably the most important systemic therapy for hormone receptor positive breast cancer. However, after an initial response to hormonal therapy, most tumors develop resistance leading to disease progression. Central mechanisms thought to be involved in this process include: 1) alterations in tumor cell physiology causing insensitivity to drug-induced apoptosis or induction of drug-detoxifying mechanisms; 2) expression of energy-dependent transporters that eject anti-cancer drugs from cells and 3) the emergence of cancer stem-like cell clones that are estrogen-independent and/or antiestrogen resistant. We and others have shown that Notch signaling mediates survival signals in ER+ breast cancer cells; induces expression of drug transporter ABCG2 (BCRP), activates ERα in the absence of estrogen and mediates survival of breast cancer stem-like cells. Previously, we demonstrated a crosstalk between ERα and Notch signaling whereby estrogen inhibits Notch activation and estrogen withdrawal or tamoxifen re-activate Notch, a possible mechanism of resistance. The mechanism of these effects has remained elusive.

Methods: we used sub-cellular fractionation and immunofluorescence staining to investigate the total expression and cellular distribution of Notch signaling components in MCF-7 cells treated with 17-β-estradiol, or estrogen-free medium.

Results: Our data shows that in cells treated with estrogen-free medium, Notch1 is located in the Lipid Rafts (LR) in the plasma membrane, along with Notch signaling components such as presenilin 1 (the catalytic subunit of γ-secretase), ADAM10 and Notch negative regulator NUMB. There is published evidence that γ-secretase is most active in lipid rafts.17-β-Estradiol modifies the membrane lipid composition and change the localization of Notch and Notch regulators (such as ADAM10, presenilin-1 and NUMB) at the plasma membrane, thereby altering the activation of Notch. These observations are consistent with a model in which the lipid composition of the plasma membrane is a critical factor in regulating the rate of Notch activation. FDA-approved cholesterol lowering drugs affect Notch signaling in ways consistent with this model.

Conclusions: Our findings indicate that endocrine therapy affects Notch signaling at least in part through alterations in membrane composition and lipid raft localization of Notch signaling components.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-04-22.

Methylprednisolone increases urinary nitrate concentrations and reduces subclinical renal injury during infrarenal aortic ischemia reperfusion

OBJECTIVE

This study tests the hypothesis that methylprednisolone may influence eNOS activity in renal arterial and venous vascular beds and impede subclinical renal injury.

SUMMARY BACKGROUND DATA

Acute renal failure is a major complication of cardiovascular surgery. Renal damage arises in part from excessive vasoconstriction mediated by an imbalance of vasoconstrictive ET-1 and vasodilatory NO produced by eNOS. While methylprednisolone may reduce subclinical renal injury as measured by urinary N-acetyl-beta-D-glucosaminidase (beta-NAG), its effects upon eNOS activity in renal arterial and venous vascular beds, reflected by urinary nitrate levels, is unclear.

METHODS

A porcine model of normotensive, euvolemic infrarenal aortic ischaemia-reperfusion was used. Forty-two pigs underwent a 60-minute laparotomy followed by 150 minutes of infrarenal ischemia and 180 minutes of reperfusion. Animals were randomized to receive methylprednisolone 30 mg/kg or placebo after induction of general anesthesia. Urinary beta-NAG levels were assessed as an index of subclinical renal injury, whereas urinary nitrate was assessed as an indicator of eNOS activity in renal arterial and venous vascular beds.

RESULTS

Methylprednisolone treatment did not influence mean arterial, central venous, or pulmonary artery wedge pressures but suppressed plasma IL-6 levels. After the ischemia-induced rise from preanaesthetic baseline levels, urinary beta-NAG levels declined to significantly lower values in the MP group, indicative of MP renal protection (P < 0.05). Conversely, urinary nitrate levels indicative of vascular e-NOS activity remained significantly and persistently higher in MP-treated animals (P < 0.05).

CONCLUSION

This study, in a porcine model of renal ischaemia-reperfusion injury, shows the benefits of methylprednisolone pretreatment in enhancing urinary nitrate levels indicative of vascular eNOS activity and the reduction of urinary beta-NAG levels, which represent subclinical renal injury.

Activation of phospholipase D in porcine tracheal smooth muscle: role of phosphatidylinositol 3-kinase and RhoA activation

Muscarinic receptor agonists transiently activate phospholipase D in tracheal smooth muscle. Muscarinic activation of phospholipase D in this tissue is dependent on activation of protein kinase C and an unidentified pathway that is not protein kinase C dependent. Cholinergic agents have also been shown to activate phospholipase D by pathways linked to the small G protein, RhoA. This study explores the relationship between muscarinic activation of phophatidylinositol 3-kinase and activation of RhoA, and examines whether phospholipase D activation is dependent on either pathway in tracheal smooth muscle. Wortmannin or 2-(4-morphonyl)-8-phenyl-4H-1-benzopyran-4-one (LY-294002), putative specific inhibitors of phophatidylinositol 3-kinase, significantly inhibit acetylcholine-induced formation of phosphatidylethanol and also block acetylcholine-induced translocation of RhoA to the membrane. In previous experiments calphostin C, a protein kinase C inhibitor, partially inhibited both acetylcholine-induced and phorbol-12-myristate-13-acetate (PMA)-induced phosphatidylethanol formation. In the present study calphostin C did not block acetylcholine-induced RhoA translocation to the membrane. However, the Rho kinase inhibitor, N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexanecarboxamide (Y-27632), significantly inhibited acetylcholine-induced phosphatidylethanol formation, but had no effect on activation of phospholipase D by PMA. Acetylcholine treatment also stimulated the phosphorylation of the 110-kDa subunit of phosphatidylinositol 3-kinase. Phosphorylation of phosphatidylinositol 3-kinase 110-kDa subunit could be blocked by wortmannin in a concentration-dependent manner, and acetylcholine-induced phosphatidylinositol 3-kinase activity was significantly inhibited by wortmannin. LY-294002 also inhibited acetylcholine-induced phosphorylation of 110-kDa subunit and activation of phosphatidylinositol 3-kinase. These results suggest that acetylcholine stimulation translocates RhoA to the membrane by a phosphatidylinositol 3-kinase-dependent mechanism and acetylcholine-induced phospholipase D stimulation is at least partly mediated via phosphatidylinositol 3-kinase, however, protein kinase C appears to activate phospholipase D independent of phosphatidylinositol 3-kinase or RhoA activation in porcine tracheal smooth muscle.

Effects of single or repeated dermal exposure to methyl parathion on behavior and blood cholinesterase activity in rats

The effects of a single or repeated dermal administration of methyl parathion on motor function, learning and memory were investigated in adult female rats and correlated with blood cholinesterase activity. Exposure to a single dose of 50 mg/kg methyl parathion (75% of the dermal LD(50)) resulted in an 88% inhibition of blood cholinesterase activity and was associated with severe acute toxicity. Spontaneous locomotor activity and neuromuscular coordination were also depressed. Rats treated with a lower dose of methyl parathion, i.e. 6.25 or 12.5 mg/kg, displayed minimal signs of acute toxicity. Blood cholinesterase activity and motor function, however, were depressed initially but recovered fully within 1-3 weeks. There were no delayed effects of a single dose of methyl parathion on learning acquisition or memory as assessed by a step-down inhibitory avoidance learning task. Repeated treatment with 1 mg/kg/day methyl parathion resulted in a 50% inhibition of blood cholinesterase activity. A decrease in locomotor activity and impairment of memory were also observed after 28 days of repeated treatment. Thus, a single dermal exposure of rats to doses of methyl parathion which are lower than those that elicit acute toxicity can cause decrements in both cholinesterase activity and motor function which are reversible. In contrast, repeated low-dose dermal treatment results in a sustained inhibition of cholinesterase activity and impairment of both motor function and memory.

Topical corticosteroids in chronic rhinosinusitis: a randomized, double-blind, placebo-controlled trial using fluticasone propionate aqueous nasal spray

Chronic rhinosinusitis (CRS) is a recalcitrant inflammatory process which has a marked detrimental impact on quality of life. At the present there is no cure for this condition, measures are taken to stop progression, and provide symptomatic relief. Topical corticosteroids are commonly prescribed in the management of CRS, but few trials show effectiveness in clinical settings. We set up a randomized, double-blind, placebo-controlled trial to study the effectiveness of a topical corticosteroid agent--fluticasone propionate aqueous nasal spray (FPANS) in patients with CRS. We measured symptoms, diary card, and rigid endoscopy scores, acoustic rhinometry, middle meatal swabs, blood tests--CRP, ESR, WBC, and eosinophil count. Measurements were done at the start of the trial, at 8 weeks, and 16 weeks where possible. Twenty-two patients completed the trial, 9 received FPANS, and 13 had placebo. There was no difference between the 2 groups on all counts. When patients were considered as one group, there was an improvement in the diary card scores (p = 0.054), comparing baseline to 8 or 16 weeks. There was no evidence that the regular use of topical corticosteroid increased the risk of developing an infection. An important observation was that the topical corticosteroid did not precipitate acute sinusitis. There is compelling evidence that topical corticosteroids down-regulate cytokine expression, and it is likely that a larger, and longer multi-centre trial may prove their efficacy in CRS.

Comparison of once daily fluticasone propionate aqueous nasal spray with once daily budesonide reservoir powder device in patients with perennial rhinitis

BACKGROUND

Previous studies comparing the corticosteroids fluticasone propionate (FP) and budesonide (BUD) in both perennial and seasonal rhinitis have shown no consistent difference between treatments. However, the therapeutic outcomes may have been influenced by study design.

OBJECTIVE

To compare the effect of FP aqueous nasal spray (ANS; 200 microg/day) with BUD reservoir powder device (RPD; 200 microg/day) on rhinitis symptoms, productivity loss and device preference in patients with perennial rhinitis.

METHODS

After a 2-week run-in period, 440 patients were randomized to receive either FPANS, BUD RPD or matched placebo (ANS or RPD) for 8 weeks, followed by an open-label 4-week follow-up treatment with FPANS. Patients completed diary card visual analogue scores for nasal symptoms, and questionnaires on satisfaction with the treatment and preferred choice of device.

RESULTS

During weeks 1-4, the visual analogue total nasal symptom scores (VATNS) in the FPANS group were significantly lower than scores in the BUD RPD group (mean difference = -17.8; 95% CI = -34.4, -1.3; P = 0.036). FPANS also significantly reduced the VATNS compared with the ANS placebo at all time-points assessed (P < or = 0.005). BUD RPD did not significantly differ from the RPD placebo at weeks 5-8 (P = 0.167), or the ANS placebo at any time-point (P < or = 0.151). Over the 8-week treatment period FPANS was significantly more effective than BUD RPD at reducing sneezing (mean difference = -4.4; 95% CI = -8.6, -0.3; P = 0.036) and nasal itching (mean difference = -5.3; 95% CI = -9.9, -0.8; P = 0.022), and was significantly superior to the ANS placebo for all symptoms assessed at weeks 1-4 and 1-8 (P < 0.016). At the same time-points BUD RPD was no better at alleviating nasal itching than the RPD placebo (P < or = 0.306), and compared with the ANS placebo, significantly reduced only one symptom; nasal blockage (P < or = 0.016). After 8 weeks of treatment, patients preferred the ANS device to the RPD (P < 0.001), and at 12 weeks a significantly greater number of patients were satisfied with FPANS treatment compared with BUD RPD (P = 0.0019) or the respective placebos (P = 0.0001).

CONCLUSION

FPANS and BUD RPD are effective therapies with a good safety profile for the treatment of perennial rhinitis but, in this direct placebo-controlled comparison, FPANS was more efficacious than BUD RPD, and the patients preferred the ANS device to the RPD.

Surgical trainees' attitudes to laparoscopic cholecystectomy: a regional survey

BACKGROUND AND STUDY AIMS

Since the introduction of laparoscopic cholecystectomy (LC), numerous articles have been written emphasising its many advantages over open cholecystectomy (OC). However, reports also highlight increased complications following LC such as bile-duct, vascular and bowel injuries. We aimed to study surgical trainees as a defined population of individuals who, with increasing exposure to cholecystectomy, would become fully aware of LC's advantages and controversies. We wished to test the hypothesis that, with increasing in-depth knowledge, they might opt for OC rather than LC if they themselves required cholecystectomy.

MATERIALS AND METHODS

We conducted a postal survey of all 133 Northern Ireland surgical trainees identified as having exposure to LC during their training. Trainees were asked whether they would undergo LC and if so with which preconditions. Similarly, if they stated a preference for open cholecystectomy they were asked to state the reason. A minimum time period of 18 months was considered adequate for trainees to become relatively more experienced in this field compared with their more junior counterparts.

RESULTS

A response rate of 80.5% (107/133) was achieved. A total of 51 of 107 trainees had at least 18 months' experience. Of the 107 who replied, 88.8% (95/107) would be willing to undergo LC. A total of 12 of 107 trainees would opt for OC, with twice as many experienced trainees (8 vs. 4) opting for this approach (n.s. [not significant]). Significantly more experienced trainees cited the use of laparoscopic cholangiography as a precondition for LC compared with their inexperienced counterparts (7 vs. 1, p = 0.020). Of 107 trainees, 19 would request use of the open first port (Hasson) technique; 14 of these had at least 18 months' experience (p = 0.009).

CONCLUSION

Our survey confirms that the majority of trainees would be willing to undergo LC. However, increased experience of LC may alter an individual's expectations about how LC should ideally be performed.

Systemic bioavailability of fluticasone propionate administered as nasal drops and aqueous nasal spray formulations

AIMS

To measure and compare the systemic bioavailability of fluticasone propionate aqueous nasal spray and a new nasal drop formulation, using a sensitive analytical method and high dose regimen.

METHODS

Volunteers received four 800 microg doses of fluticasone propionate as a nasal spray or drops over 2 days, separated by an 8 h dose interval. On day 2, blood samples were collected for assay of fluticasone propionate plasma concentrations.

RESULTS

The mean systemic exposure, for both formulations was 8.5 pg x ml(-1) x h (drops) and 67.5 pg x ml(-1) x h (spray). Mean absolute bioavailabilities were estimated to be 0.06% (drops) and 0.51% (spray), by reference to historical intravenous data.

CONCLUSIONS

Both formulations exhibited low systemic bioavailability, even at 12 times the normal daily dose. The bioavailability from the nasal drops was approximately eight times lower than from the nasal spray.

Limited heterogeneity of HIV type 1 in infected mothers correlates with lack of vertical transmission

The human immunodeficiency virus type 1 (HIV-1) envelope V3 region sequences of peripheral blood mononuclear cell DNA were analyzed from three nontransmitting mothers (infected mothers who failed to transmit HIV-1 to their infants in the absence of antiretroviral therapy), including one mother with two deliveries, and compared with the sequences of seven previously analyzed transmitting mothers. The coding potential of the envelope open reading frame, including several patient-specific amino acid motifs and previously described molecular features across the V3 region, were highly conserved. There was a low degree of heterogeneity within the sequences of each nontransmitting mother compared with the sequences of transmitting mothers. In addition, the estimates of genetic diversity of nontransmitting mother sequences were significantly lower compared with transmitting mother sequences. Phylogenetic analysis showed that the sequences of each nontransmitting mother formed distinct clusters that were well discriminated from each other and the sequences of seven transmitting mothers. In conclusion, a low degree of HIV-1 genetic heterogeneity in these infected mothers correlates with lack of vertical transmission; this finding may be useful in developing strategies for further prevention of maternal-fetal transmission.

Phosphatidylethanol stimulates calcium-dependent cytosolic phospholipase A(2) activity of a macrophage cell line (RAW 264.7)

The synthesis of inflammation mediators produced from arachidonic acid is regulated primarily by the cellular concentration of free arachidonic acid. Since intracellular arachidonic acid is almost totally present as phospholipid esters, the concentration of intracellular arachidonic acid is primarily dependent on the balance between the release of arachidonic acid from membrane phospholipids and the uptake of arachidonic acid into membrane phospholipids. Cytosolic phospholipase A(2) is a calciumdependent enzyme that catalyzes the stimulus-coupled hydrolysis of arachidonic acid from membrane phospholipids. Following exposure of macrophages to various foreign or endogenous stimulants, cytosolic phospholipase A(2) is activated. Treatment with these compounds may also stimulate phospholipase D activity, and, in the presence of ethanol, phospholipase D catalyzes the synthesis of phosphatidylethanol. A cell-free system was used to evaluate the effect of phosphatidylethanol on cytosolic phospholipase A(2) activity. Phosphatidylethanol (0.5 microM) added to 1-stearoyl-2-[(3)H]-arachidonoyl-sn-glycero-3-phosphocholine vesicles stimulated cytosolic phospholipase A(2) activity. However, high concentrations (20-100 microM) of phosphatidylethanol inhibited cytosolic phospholipase A(2) activity. Phosphatidic acid, the normal phospholipase D product, also stimulated cytosolic phospholipase A(2) activity at 0.5 microM, but had an inhibitory effect on cytosolic phospholipase A(2) activity at concentrations of 50 and 100 microM. Ethanol (20-200 mM), the precursor of phosphatidylethanol, added directly to the assay did not alter cytosolic phospholipase A(2) activity. These results suggest that phosphatidylethanol alters the physical properties of the substrate, and at lower concentrations of anionic phospholipids the substrate is more susceptible to hydrolysis. However, at high concentrations, phosphatidylethanol either reverses the alterations in physical properties of the substrate or phosphatidylethanol may be competing as the substrate. Both interactions may result in lower cytosolic phospholipase A(2) activity.

The moral justification scale: reliability and validity of a new measure of care and justice orientations

Research increasingly suggests that there are limitations to Kohlberg's theory of moral development. Gilligan in particular has observed that Kohlberg's theory considers abstract principled reasoning as the highest level of moral judgment, and penalizes those who focus on the interpersonal ramifications of a moral decision. Gilligan calls these justice and care orientations. The present paper describes the development of the Moral Justification Scale, an objective measure of the two orientations. The scale consists of six vignettes, of which two are justice oriented, two are care oriented, and two are mixed, incorporating both orientations. Construct validity was evaluated by expert judges and, overall, was high. Cronbach's alpha was .75 for the Care subscale and .64 for the Justice subscale, indicating adequate internal consistency. Split-half reliabilities were as follows: Care, r = .72, p < .01, and Justice, r = .60, p < .05. Regarding test-retest reliability (approximately two weeks), r = .61, p < .05, for Care; r = .69, p < .05, for Justice. Neither subscale correlated significantly with the Marlowe-Crowne Social Desirability Scale. Thus, the Moral Justification Scale shows promise as an easily administered, objectively scored measure of Gilligan's constructs of care and justice.

Lipopolysaccharide-stimulated nitric oxide production and inhibition of cell proliferation is antagonized by ethanol in a clonal macrophage cell line

Both chronic and acute ethanol exposure have been shown to be cytotoxic and also to disrupt normal cell function or responses in a variety of cell types. Macrophage function has specifically been shown to be disrupted by chronic ethanol exposure by mechanisms that have not been elucidated. It is known that exposure of macrophages to lipopolysaccharide (LPS) from gram-negative bacteria will decrease the number of cells. Since increased exposure to endotoxin is often associated with chronic alcoholism, this may be one mechanism to account for loss of macrophages in alcoholic patients. The loss of macrophages, as a consequence of endotoxin treatment, appears to be linked to cell activation and, in particular, LPS-stimulated synthesis of nitric oxide which has been suggested to cause an increase in apoptosis. Ethanol also increases apoptosis in some cell types but, in general, ethanol inhibits activation of macrophages. Thus, the overall effect on cell numbers and cell proliferation elicited by treating macrophages concomitantly with ethanol and LPS depends on the balance between inhibiting LPS-mediated activation and the actions of ethanol. The interaction between ethanol and LPS was investigated in a macrophage cell line (RAW 264.7 cells) by measuring nitric oxide production and cell proliferation. A 24-h exposure to ethanol (100 mM) decreased [3H]-thymidine incorporation significantly. LPS treatment elicited a concentration-dependent decrease in [3H]-thymidine incorporation at LPS concentrations of 0.1 ng/ml to 1000 ng/ml and stimulated nitric oxide production at concentrations above 1 ng/ml. LPS-stimulated nitric oxide production was inhibited by ethanol (20 to 100 mM) and the nitric oxide synthesis inhibitor, N(G)Nitro-L-arginine methyl L-NAME) ester (100 and 500 microM). However, LPS-inhibited [3H]-thymidine incorporation was not be totally reversed by ethanol- or L-NAME-treatment. A direct correlation between nitric oxide production and inhibition of cell proliferation could not be demonstrated. However, it appears that ethanol and LPS do affect some common mechanism(s) in this cell line.

Activation of protein kinase A increases phospholipase D activity and inhibits phospholipase D activation by acetylcholine in tracheal smooth muscle

Increased cAMP by stimulation of adenylyl cyclase with forskolin or by beta-adrenoceptor activation with isoproterenol increased phospholipase D (PLD) activity in tracheal smooth muscle strips. PLD activity was measured by the accumulation of phosphatidylethanol. A linear increase in the concentration of phosphatidylethanol was observed over 20 min in muscle strips treated with either forskolin or isoproterenol. Cholinergic stimulation with acetylcholine (ACh), by contrast, caused a rapid increase in phosphatidylethanol followed by a slow decline in the concentration of phosphatidylethanol from 5 to 20 min in the continued presence of ACh. Concomitant treatment with ACh and either forskolin or isoproterenol eliminated the rapid increases in phosphatidylethanol associated with ACh treatment. The response to forskolin or isoproterenol was not influenced by ACh. Inhibition of protein kinase C with calphostin C or bisindolylmaleimide I had no effect on isoproterenol- or forskolin-stimulated PLD activity but inhibited ACh-activated PLD activity. Protein kinase A (PKA) inhibitors H-89 and KT5720 significantly decreased forskolin- and isoproterenol-mediated activation of PLD activity. PKA inhibition also eliminated inhibition of ACh-stimulated PLD activity by forskolin or isoproterenol. Activation of adenylyl cyclase by forskolin or by isoproterenol caused increased phosphorylation of phospholipase C-beta(2) isoform and reduced the formation of inositol phosphates after ACh stimulation of muscarinic receptors. These results suggest that increasing the concentration of cAMP activates PLD via activation of PKA and that the increased activity of PKA also inhibits cholinergic stimulation of PLD, in part at least by inhibiting the activation of phospholipase C by ACh.

How can obese weight controllers minimize weight gain during the high risk holiday season? By self-monitoring very consistently

This study examined the efficacy of augmenting standard weekly cognitive-behavioral treatment for obesity with a self-monitoring intervention during the high risk holiday season. Fifty-seven participants in a long-term cognitive-behavioral treatment program were randomly assigned to self-monitoring intervention or comparison groups. During 2 holiday weeks (Christmas-New Years), the intervention group's treatment was supplemented with additional phone calls and daily mailings, all focused on self-monitoring. As hypothesized, the intervention group self-monitored more consistently and managed their weight better than the comparison group during the holidays. However, both groups struggled with weight management throughout the holidays. These findings support the critical role of self-monitoring in weight control and demonstrate the benefits of a low-cost intervention for assisting weight controllers during the holidays.

An unusual iatrogenic cause of right coronary air embolism

A 62-year-old woman undergoing redo mitral valve replacement was noted to have persistent intracardiac air following standard deairing procedures. Transesophageal echocardiography (TEE) identified air bubbles entering the left atrium from the right superior pulmonary vein. Exploration of the pleural cavity revealed a fistula between the pulmonary parenchyma and the right superior pulmonary vein caused by the atriotomy closure suture transfixing the edge of the lung, which was repaired with immediate disappearance of the air emboli. This demonstrates that transesophageal echocardiography is an invaluable aid to ensuring complete deairing after open heart procedures.

How can obese weight controllers minimize weight gain during the high risk holiday season? By self-monitoring very consistently

This study examined the efficacy of augmenting standard weekly cognitive-behavioral treatment for obesity with a self-monitoring intervention during the high risk holiday season. Fifty-seven participants in a long-term cognitive-behavioral treatment program were randomly assigned to self-monitoring intervention or comparison groups. During 2 holiday weeks (Christmas-New Years), the intervention group's treatment was supplemented with additional phone calls and daily mailings, all focused on self-monitoring. As hypothesized, the intervention group self-monitored more consistently and managed their weight better than the comparison group during the holidays. However, both groups struggled with weight management throughout the holidays. These findings support the critical role of self-monitoring in weight control and demonstrate the benefits of a low-cost intervention for assisting weight controllers during the holidays.

Cytotoxicity of short-chain alcohols

Ethanol and other short-chain alcohols elicit a number of cellular responses that are potentially cytotoxic and, to some extent, independent of cell type. Aberrations in phospholipid and fatty acid metabolism, changes in the cellular redox state, disruptions of the energy state, and increased production of reactive oxygen metabolites have been implicated in cellular damage resulting from acute or chronic exposure to short-chain alcohols. Resulting disruptions of intracellular signaling cascades through interference with the synthesis of phosphatidic acid, decreases in phosphorylation potential and lipid peroxidation are mechanisms by which solvent alcohols can affect the rate of cell proliferation and, consequently, cell number. Nonoxidative metabolism of short-chain alcohols, including phospholipase D-mediated synthesis of alcohol phospholipids, and the synthesis of fatty acid alcohol esters are additional mechanisms by which alcohols can affect membrane structure and compromise cell function.

After-hours telephone triage and advice in private and nonprivate pediatric populations

OBJECTIVES

To compare the content of after-hours medical triage and advice calls regarding private practice patients vs nonprivate practice patients and to assess caregiver compliance with advice resulting from these calls.

DESIGN

Survey of after-hours medical triage and advice calls during a 2-week period (September 1 through 15, 1996).

SETTING

Three private practices (serving approximately 24 000 patients) and 1 urban hospital-based, non-private practice (serving approximately 12 000 patients).

SUBJECTS

After-hours medical triage and advice calls from caregivers of patients receiving their primary care in these settings.

MAIN OUTCOME MEASURE

Compliance with recommended emergency department (ED) or office visit referrals.

RESULTS

A total of 286 calls regarding private practice patients and 377 calls regarding nonprivate practice patients were received (P<.001). Eighty-one calls were referred by the nurse directly to the physician. Fifty-nine private practice patients and 59 nonprivate practice patients were referred to the ED. Caregivers of 94 private practice patients and 132 nonprivate practice patients were given home treatment advice. Appointments to be seen at their primary care source were given for 78 private practice patients and 160 nonprivate practice patients. Non-private practice patients were more likely to be referred for office care (P=.005); private practice patients were more likely to be referred to the ED (P=.01). Compliance with ED referrals was 42% for patients of nonprivate practice and 46% for private practice; for office visit referrals, compliance was 64% for nonprivate practice and 69% private practice patients (P=.71 for compliance with ED referrals and P=.40 for compliance with office referrals).

CONCLUSIONS

Compliance with recommended physician encounters was not significantly different (and lower than expected) in both groups of patients. Private practice patients are more likely to be referred to the ED. Calls for nonprivate practice patients are more frequent and these patients are more likely to be referred to their primary care source. This difference may be due to caregivers of patients from nonprivate practices seeking advice for less serious conditions. Physicians should address telephone medicine with caregivers proactively during health maintenance visits.

Activation of muscarinic receptors in porcine airway smooth muscle elicits a transient increase in phospholipase D activity

Phospholipase D (PLD) is a phosphodiesterase that catalyses hydrolysis of phosphatidylcholine to produce phosphatidic acid and choline. In the presence of ethanol, PLD also catalyses the formation of phosphatidylethanol, which is a unique characteristic of this enzyme. Muscarinic receptor-induced changes in the activity of PLD were investigated in porcine tracheal smooth muscle by measuring the formation of [3H]phosphatidic acid ([3H]PA) and [3H]phosphatidylethanol ([3H]PEth) after labeling the muscle strips with [3H]palmitic acid. The cholinergic receptor agonist acetylcholine (Ach) significantly but transiently increased formation of both [3H]PA and [3H]PEth in a concentration-dependent manner (>105-400% vs. controls in the presence of 10(-6) to 10(-4) M Ach) when pretreated with 100 mM ethanol. The Ach receptor-mediated increase in PLD activity was inhibited by atropine (10(-6) M), indicating that activation of PLD occurred via muscarinic receptors. Activation of protein kinase C (PKC) by phorbol-12-myristate-13-acetate (PMA) increased PLD activity that was effectively blocked by the PKC inhibitors calphostin C (10(-8) to 10(-6) M) and GFX (10(-8) to 10(-6) M). Ach-induced increases in PLD activity were also significantly, but incompletely, inhibited by both GFX and calphostin C. From the present data, we conclude that in tracheal smooth muscle, muscarinic acetylcholine receptor-induced PLD activation is transient in nature and coupled to these receptors via PKC. However, PKC activation is not solely responsible for Ach-induced activation of PLD in porcine tracheal smooth muscle.

Weight control during the holidays: highly consistent self-monitoring as a potentially useful coping mechanism

The study examined the extent to which trait self-monitoring (the systematic observation and recording of target behaviors) was related to weight control during the high-risk holiday season. The participants (32 women, 6 men) averaged 223.1 lbs (101.41 kg), 57.2% overweight, 50.2 weeks of participation, and 21.3 lbs (9.68 kg) lost at the beginning of the study. Consistency of self-monitoring and weight changes were assessed for 3 holiday versus 7 nonholiday weeks. Analyses of variance (Consistency of Self-Monitoring Groups x Holiday/Nonholiday Weeks) revealed that participants gained 500% more weight per week during holiday compared with nonholiday weeks. Only participants in the most consistent self-monitoring quartile averaged any weight loss over the 10 weeks of the study and during the holiday weeks.

Ethanol inhibition of phagocytosis and superoxide anion production by microglia

Ethanol consumption has been associated with aberrant immune responses resulting in increased susceptibility to infection including opportunistic infections of the central nervous system. We have investigated the effects of chronic ethanol treatment on phagocytosis and production of superoxide anion by microglia. Phagocytosis of radio-labeled opsonized E. coli was markedly suppressed by treating microglia with ethanol. The unstimulated synthesis of superoxide anion was not altered by ethanol treatment of microglia, but ethanol treatment effectively suppressed phorbol-12 myristate-13 acetate-stimulated microglia superoxide anion production. The results indicate that ethanol inhibition of microglia function may play a role in increased susceptibility for central nervous system infections, particularly in immunocompromised subjects.

Ethanol-induced apoptosis in human HL-60 cells

The mechanisms responsible for aberrant immune function associated with chronic ethanol use remain obscure, but a decrease in monocyte numbers is often reported for individuals who chronically abuse ethanol. We investigated, using human HL-60 promyelocytic cell line, the possibility that ethanol induces apoptosis which contributes to decreased monocyte numbers. Characteristic features of apoptosis were observed 4 days after ethanol treatment, as documented by increased DNA fragmentation; enhanced expression of phosphatidylserine, an early marker of apoptosis; and the appearance of a hypodiploid apoptotic cell population identified by flow cytometry analysis of the cell cycle. Treatment with the protein kinase C inhibitor, GF 109203X, potentiated ethanol-induced apoptosis. Direct induction of human HL-60 cell apoptosis by ethanol and potentiation of ethanol-induced apoptosis by inhibiting protein kinase C provides a partial explanation for the cytotoxic effects of ethanol on hematopoietic progenitor cells and establishes a link between inhibiting protein kinase C activity and ethanol-induced apoptosis.

Negative and positive regulation of astrocyte DNA synthesis by ethanol

Ethanol suppression of astrocyte mitogenesis is well recognized but ethanol, under some conditions, has also been shown to stimulate astrocyte proliferation. This study addressed the role of protein kinase C and other mitogenic factors as mechanisms responsible for the bidirectional effects of ethanol on astrocyte DNA synthesis. Ethanol treatment inhibited astrocyte DNA synthesis both at 4 hr (short term) and 24 hr (long term) in serum free medium. In contrast, when the medium contained serum, ethanol was less effective in inhibiting DNA synthesis at 4 hr and treatment with ethanol for 24 hr increased DNA synthesis. Protein kinase C activity was increased in cells treated with ethanol for either 4 or 24 hr. Ethanol inhibition of DNA synthesis in serum free medium was not reversed by down regulating protein kinase C. In contrast, downregulating protein kinase C activity by continuous treatment with phorbol myristic acetate partially reversed the effect ethanol had on DNA synthesis. Also, directly inhibiting protein kinase C with H-7 in cells maintained and treated in the presence of serum abolished the stimulatory effect ethanol had on DNA synthesis. It appears that the negative regulation of astrocyte DNA synthesis by ethanol occurs by protein kinase C and serum independent mechanisms whereas adaptive or stimulatory effects of ethanol on astrocyte DNA synthesis requires the interaction of protein kinase C with other factors present in serum.

Effect of exogenous GM1 on ethanol sensitivity in selectively bred mouse lines

Ethanol sensitive long-sleep (LS) and ethanol resistant short-sleep (SS) mice are lines that have been genetically selected for differential central nervous system sensitivities to the hypnotic effect of ethanol. Because they were genetically selected only for differences in sensitivity to ethanol hypnosis, biochemical and physiological differences between them are likely related to their differential ethanol sensitivity. The synaptosomal and whole brain concentration of GM1 ganglioside was previously shown to differ significantly between the lines. Further, GM1 alters membrane responses to ethanol, including a differential effect on LS and SS synaptosomal membrane disordering. Therefore, GM1 was administered intracerebroventricularly (i.c.v.) with micro-osmotic pumps, to partially bypass the blood-brain barrier and to test its effect on CNS sensitivity to ethanol hypnosis in LS and SS mice. In the first experiment, 3 days' infusion of GM1 (20 micrograms/microliters, 24 microliters/day), saline control and treated LS and SS mice were tested for both regaining of the righting reflex and waking brain ethanol concentration. Incorporation of 3H-GM1 into brain membranes was verified by scintillation spectroscopy. GM1 did not alter ethanol sensitivity or brain ethanol concentration at time of waking in LS mice. Conversely, SS mice treated with GM1 were significantly more sensitive to ethanol hypnosis than saline controls as measured by the time to regain the righting reflex ("sleep time") and waking brain ethanol concentrations. In the second experiment, GM1-treated SS mice were again significantly more sensitive to ethanol hypnosis than saline controls. GM1 incorporation into the contralateral and ipsilateral cerebral hemispheres was determined by high-performance liquid chromatography.

Phosphorylated zidovudine concentrations in mononuclear cells in pediatric patients with human immunodeficiency virus infections

PURPOSE

The efficacy of zidovudine (ZDV) in patients with HIV-1 infection may decrease over time due to its decreased activation. The objectives of this study were to determine ZDV concentrations in plasma, active phosphorylated zidovudine (pZDV) concentrations in mononuclear cells, and assess the markers of immune function and drug toxicity during extended therapy.

METHODS

Pediatric patients (aged 3 months to 18 years) with HIV-1-infection were enrolled in the study. For each patient, one blood sample was collected at each of eight routine visits to measure plasma ZDV and ZDV concentrations by a radioimmunoassay. Data including demographic information, immunological markers (CD2+, CD3+, CD4+, CD5+/19+, CD8+, CD16+, CD19+, CD38+/8+ lymphocytes), hematologic function (absolute neutrophil count, white blood cell with differential, hemoglobin, and red blood cell count), concurrent medications, and dosage regimens were obtained.

RESULTS

The data from 13 patients were as follows: age: 2-18 years; range of ZDV dose: 76-238 mg/m2, total ZDV daily dosage: 264-720 mg/m2; duration of ZDV therapy prior to study: 1 to 37 months; time in study: 180-394 days; plasma ZDV concentration range: 5-1021 ng/ml; and pZDV concentration range: 0-5.382 pmol/10(6) cells. Both plasma ZDV and intracellular pZDV concentrations had a marked inter- and intrapatient variability. The pZDV concentrations decreased significantly over time in one pediatric patient (p < 0.05), tended to decrease but not significantly in three patients, and no decrease was detected in nine patients due to high variability. In our population, neither immunological nor drug toxicity markers changed over time.

CONCLUSIONS

Marked inter- and intrapatient variability in pZDV concentrations was observed. The ability to phosphorylate ZDV, however, did not appear to change significantly in 12 of 13 pediatric patients with HIV-1 infection during the study period of 6-13 months.

The relationship of homophobia to intimacy in heterosexual men

Interpersonal intimacy is more difficult to achieve for American men than women. Research has shown that men disclose less, have fewer close friendships, and are viewed by their wives as low in intimacy. Among the barriers to intimacy among men, Tognoli (1980) suggested that homophobia is the most powerful. The present study tested this idea by asking men to disclose a personal secret to either a male confidant, a female confidante, or by writing the secret. It was expected that the presence of a male confidant would stimulate homophobic feelings and inhibit disclosure, while the other two conditions would result in more personal disclosure. A correlation between intimacy of disclosure and level of homophobia was also expected. Subjects were 75 heterosexual men, 31 to 50 years of age, randomly assigned to one of the three conditions. They also completed the Miller Social Intimacy Scale, the Jourard Self-Disclosure Questionnaire, the Index of Homophobia, and the Marlowe-Crowne Social Desirability Scale. Results showed that homophobia was inversely related to level of social intimacy. There was some indication that homophobia does relate to less intimate disclosure to other males. Thus this study found some support for the idea that homophobia is an obstacle to intimacy for men.

The effects of pretraining on group psychotherapy for incest-related issues

The effects of written, cognitive pretraining on self-reported self-disclosure and cohesion in group psychotherapy were studied. Subjects were members of time-limited psychotherapy groups that focused on incest-related issues. The experimental groups were given written cognitive pretraining designed to increase self-reported self-disclosure and cohesion. The control groups received general group information. Subjects in the pretrained groups reported higher levels of self-perceived self-disclosure than the control groups after sessions 4 (p = 0.003) and 8 (p = 0.003). Self-reported self-disclosure did not increase over time for pretrained or nonpretrained subjects. Cohesion did not differ across groups, but increased over time for experimental subjects (p = .008), and not for control subjects.

Neurodevelopmental outcome of infants with viral meningitis in the first three months of life

We prospectively evaluated the neurodevelopmental outcome of infants with documented viral meningitis to determine (1) whether deficits in physical growth, development, speech and language, hearing, or intelligence occur; and (2) if so, at what age these deficits can be detected. Sixteen infants with documented enteroviral meningitis under the age of 90 days and a control group of 13 patients matched for age, race, sex, and socioeconomic status were followed up prospectively for 3 years with annual evaluations, which included a developmental evaluation by a pediatric developmentalist, articulation and language tests by a speech-language pathologist (Sequenced Inventory of Communication Development, Receptive-Expressive Emergent Language Scale (REEL), Preschool Language Scale (PLS), Revised Peabody Picture Vocabulary Test (PPVT-R), Photo Articulation Test, audiometric screening), and intelligence tests by a psychometrist (Bayley Scales of Infant Development [BSID] and Stanford-Binet). No deficits were demonstrated in growth, development, hearing, BSID, articulation, and expressive language. Subtle but significant (P < 0.05) deficits were documented in the study group compared with the control group in the receptive component of the REEL, all subsections of the PLS, the PPVT-R, and the verbal comprehension/language-processing section (Factor II) of the Stanford-Binet. These differences could be reliably detected by 3 years of age. We conclude that viral meningitis in young infants may cause subtle deficits in language skills, particularly receptive language. We recommend that children who have had enteroviral meningitis during early infancy be monitored carefully for language development and, perhaps, receive increased language stimulation in the home prior to school entry in order to optimize their learning potential.