MitoQ supplementation augments acute exercise-induced increases in muscle PGC1α mRNA and improves training-induced increases in peak power independent of mitochondrial content and function in untrained middle-aged men

The role of mitochondrial ROS in signalling muscle adaptations to exercise training has not been explored in detail. We investigated the effect of supplementation with the mitochondria-targeted antioxidant MitoQ on a) the skeletal muscle mitochondrial and antioxidant gene transcriptional response to acute high-intensity exercise and b) skeletal muscle mitochondrial content and function following exercise training. In a randomised, double-blind, placebo-controlled, parallel design study, 23 untrained men (age: 44 ± 7 years, VO_2peak: 39.6 ± 7.9 ml/kg/min) were randomised to receive either MitoQ (20 mg/d) or a placebo for 10 days before completing a bout of high-intensity interval exercise (cycle ergometer, 10 × 60 s at VO_2peak workload with 75 s rest). Blood samples and vastus lateralis muscle biopsies were collected before exercise and immediately and 3 h after exercise. Participants then completed high-intensity interval training (HIIT; 3 sessions per week for 3 weeks) and another blood sample and muscle biopsy were collected. There was no effect of acute exercise or MitoQ on systemic (plasma protein carbonyls and reduced glutathione) or skeletal muscle (mtDNA damage and 4-HNE) oxidative stress biomarkers. Acute exercise-induced increases in skeletal muscle peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1-α) mRNA expression were augmented in the MitoQ group. Despite this, training-induced increases in skeletal muscle mitochondrial content were similar between groups. HIIT-induced increases in VO_2peak and 20 km time trial performance were also similar between groups while training-induced increases in peak power achieved during the VO_2peak test were augmented in the MitoQ group. These data suggest that training-induced increases in peak power are enhanced following MitoQ supplementation, which may be related to the augmentation of skeletal muscle PGC1α expression following acute exercise. However, these effects do not appear to be related to an effect of MitoQ supplementation on exercise-induced oxidative stress or training-induced mitochondrial biogenesis in skeletal muscle.

Hybrid integration methodology for quantum cascade lasers with germanium waveguides in mid-IR

Mid-infrared quantum cascade lasers (QCLs) operating around 5.7 μm have been integrated with germanium waveguides on silicon substrates. QCL bars have been designed and fabricated at the University of Sheffield for the purpose of integration. This hybrid approach uses flip-chip technology that has been successfully transferred from a silicon-on-oxide (SOI) platform working at communication wavelengths, demonstrating the flexibility of this approach. Integration challenges are introduced, and solutions discussed, leading to the next iteration of design presented here.

Mitochondria-targeted antioxidant supplementation improves 8 km time trial performance in middle-aged trained male cyclists

BACKGROUND

Exercise increases skeletal muscle reactive oxygen species (ROS) production, which may contribute to the onset of muscular fatigue and impair athletic performance. Mitochondria-targeted antioxidants such as MitoQ, which contains a ubiquinone moiety and is targeted to mitochondria through the addition of a lipophilic triphenylphosphonium cation, are becoming popular amongst active individuals as they are designed to accumulate within mitochondria and may provide targeted protection against exercise-induced oxidative stress. However, the effect of MitoQ supplementation on cycling performance is currently unknown. Here, we investigate whether MitoQ supplementation can improve cycling performance measured as time to complete an 8 km time trial.

METHOD

In a randomized, double-blind, placebo-controlled crossover study, 19 middle-aged (age: 44 ± 4 years) recreationally trained (VO_2peak: 58.5 ± 6.2 ml·kg^- 1·min^- 1, distance cycled per week during 6 months prior to study enrollment: 158.3 ± 58.4 km) male cyclists completed 45 min cycling at 70% VO_2peak followed by an 8 km time trial after 28 days of supplementation with MitoQ (20 mg·day^- 1) and a placebo. Free F₂-isoprostanes were measured in plasma samples collected at rest, after 45 min cycling at 70% VO_2peak and after completion of the time trial. Respiratory gases and measures of rating of perceived exertion (RPE) were also collected.

RESULTS

Mean completion time for the time trial was 1.3% faster with MitoQ (12.91 ± 0.94 min) compared to placebo (13.09 ± 0.95 min, p = 0.04, 95% CI [0.05, 2.64], d = 0.2). There was no difference in RPE during the time trial between conditions (p = 0.82) despite there being a 4.4% increase in average power output during the time trial following MitoQ supplementation compared to placebo (placebo; 270 ± 51 W, MitoQ; 280 ± 53 W, p = 0.04, 95% CI [0.49, 8.22], d = 0.2). Plasma F₂-isoprostanes were lower on completion of the time trial following MitoQ supplementation (35.89 ± 13.6 pg·ml^- 1) compared to placebo (44.7 ± 16.9 pg·ml^- 1 p = 0.03).

CONCLUSION

These data suggest that MitoQ supplementation may be an effective nutritional strategy to attenuate exercise-induced increases in oxidative damage to lipids and improve cycling performance.

Inflexibility of the plasma miRNA response following a high-carbohydrate meal in overweight insulin-resistant women

Context

Metabolic inflexibility is a characteristic of insulin resistance, limiting the ability to transiently regulate oxidative metabolism and gene expression in response to nutrient availability. Little is known of the flexibility of post-transcriptional regulation, including circulatory miRNAs (c-miRNAs).

Design

The abundances of targeted c-miRNAs, with reported functions in metabolic regulation, were analysed in response to a high-carbohydrate meal in healthy weight insulin-sensitive (IS) and overweight insulin-resistant (IR) women.

Participants

Age-matched healthy weight IS (n = 20, BMI = 24.3 ± 0.70) and overweight IR (n = 20, BMI = 28.6 ± 0.67) women.

Methods

An abundance of c-miRNAs was quantified prior to and following a high-carbohydrate breakfast meal (2500 kJ; 50% carbohydrate, 20% fat and 27% protein). Target genes of the differentially regulated c-miRNA were measured in RNA extracted from circulatory peripheral blood mononuclear cells (PBMCs).

Results

In healthy weight IS women, both miR-15a-5p (p = 0.03) and miR-17-5p (p < 0.01) levels were halved at 4 h post-meal. These miRNA remained unaltered following the same meal in the overweight IR women. Furthermore, amongst genes targeted by these miRNA, CPT1A (p = 0.01) and IL8 (p = 0.03) had also reduced expression 4 h post-meal only in the healthy weight IS women.

Conclusions

The study findings provide preliminary evidence for a possible extension of metabolic inflexibility to include c-miRNAs.

Trial registration

The clinical trial is registered with Australian New Zealand Clinical Trials Registry under Trial registration: ANZCTR: ACTRN12615001108505. Registered on 21 October 2015.

Circulatory miRNA biomarkers of metabolic syndrome

AIMS

Circulatory microRNAs (c-miRNAs) exert important roles in the molecular dysregulation of cardio-metabolic diseases. However, little is known whether dysregulated miRNA expression occurs when risk factors are elevated, as in the metabolic syndrome (MetS). This study quantified c-miRNA expression in individuals with MetS compared to healthy, further examining the relationship of gene pathways with the underlying pathogenesis.

METHODS

Expression of 26 miRNAs was quantified in plasma from 40 women (20 healthy and 20 MetS) and 39 men (20 healthy and 19 MetS) by qPCR. In silico analysis was performed to investigate biological effects of the dysregulated miRNAs. Dysregulated miRNA expression was further validated in an independent cohort of 20 women (10 healthy and 10 MetS).

RESULTS

Regression model adjusted for age and sex identified miR-15a-5p, miR-17-5p, miR-370-3p and miR-375 as important predictors of MetS presence. Analysis of predictive miRNAs in the validation cohort strengthened the relationship with miR-15a-5p and miR-17-5p expression. These miRNAs share genes involved in the regulation of metabolic pathways including insulin, wnt, fatty acid metabolism and AMPK.

CONCLUSIONS

miR-15a-5p and miR-17-5p were identified as predictive biomarkers of MetS, irrespective of sexes, further demonstrating the relationship of c-miRNAs to known pathways of metabolic disturbances present in cardio-metabolic diseases.

Regulation of Amino Acid Transporters and Sensors in Response to a High protein Diet: A Randomized Controlled Trial in Elderly Men

BACKGROUND

The mammalian target of rapamycin complex 1 (mTORC1) is fundamental for many cellular processes, yet it is often dysregulated with aging. Increased amino acid (AA) availability is correlated with the expression of AA transporters (AAT) and mTORC1 activity. Although many AA sensors and mediators have been proposed to relay the AA signal to mTORC1, it has not yet been determined if chronic dietary intervention affects the expression of AAT, sensors and mediators and their relationships with mTORC1 activity.

OBJECTIVE AND DESIGN

This study investigated whether the consumption of a diet containing either the current recommended daily allowance (RDA) of protein intake (0.8 g/kg/d) or twice the RDA (2RDA) for ten weeks affected the expression of targets associated with AA transport, sensing and mTORC1 regulation in 26 older men (70-81 years).

METHOD

Muscle biopsies were collected before and after the intervention under fasting conditions. Diets were controlled by providing fully prepared meals and snacks. Western blot and quantitative polymerase chain reaction were used to measure protein and gene expression respectively.

RESULTS

Consumption of 2RDA reduced the protein expression of L-type amino acid transporter 1 (LAT1). However, plasma leucine concentration and basal mTORC1 activity were unaltered. The downregulation of LAT1 did not affect the expression of AA sensors and mediators, including leucyl tRNA synthetase (LRS), cytosolic arginine sensor for mTORC1 (CASTOR1), Sestrin2 and Rag proteins. Instead, total ribosomal protein S6 (RPS6) was upregulated with 2RDA.

CONCLUSION

Ten weeks of 2RDA diet did not affect the fasting mTORC1 signaling, but increased total RPS6 might suggest improved muscular translational capacity to maintain muscular mass.

Micromanipulation of InP lasers with optoelectronic tweezers for integration on a photonic platform

The integration of light sources on a photonic platform is a key aspect of the fabrication of self-contained photonic circuits with a small footprint that does not have a definitive solution yet. Several approaches are being actively researched for this purpose. In this work we propose optoelectronic tweezers for the manipulation and integration of light sources on a photonic platform and report the positional and angular accuracy of the micromanipulation of standard Fabry-Pérot InP semiconductor laser die. These lasers are over three orders of magnitude bigger in volume than any previously assembled with optofluidic techniques and the fact that they are industry standard lasers makes them significantly more useful than previously assembled microdisk lasers. We measure the accuracy to be 2.5 ± 1.4 µm and 1.4 ± 0.4° and conclude that optoelectronic tweezers are a promising technique for the micromanipulation and integration of optoelectronic components in general and semiconductor lasers in particular.

Older Adults Have Delayed Amino Acid Absorption after a High Protein Mixed Breakfast Meal

OBJECTIVES

To measure the postprandial plasma amino acid appearance in younger and older adults following a high protein mixed meal.

DESIGN

Cross-sectional study.

SETTING

Clinical research setting.

PARTICIPANTS

Healthy men and women aged 60-75 (n=15) years, and young controls aged 20-25 years (n=15) matched for body mass index and insulin sensitivity based on the homeostatic model assessment of insulin resistance.

INTERVENTION

High protein mixed meal of complete food products.

MEASUREMENTS

Circulating amino acid concentrations were determined hourly before and for 5 hours after meal ingestion.

RESULTS

There was no difference between cohorts in postprandial appearance of non-essential amino acids, or area under the curve of any individual amino acid or amino acid class. However, older adults had higher baseline concentrations of aspartic acid, glutamic acid, glycine, ornithine, threonine and tyrosine and lower baseline concentrations of hydroxyproline, isoleucine, leucine, methionine and valine compared to younger adults. Younger adults showed peak essential (EAA) and branched-chain amino acid (BCAA) concentrations at 1 hour post meal while older adults' peak EAA and BCAA concentration was at 3 hours. Similarly, peak total amino acid concentrations were at 3 hours in older adults.

CONCLUSION

Older adults digested and absorbed the protein within a mixed meal more slowly than younger adults. Delayed absorption of AA following a mixed meal of complete food products may suppress or delay protein synthesis in senescent muscle.

Two-photon absorption and all-optical modulation in germanium-on-silicon waveguides for the mid-infrared

The nonlinear absorption properties of a germanium-on-silicon waveguide have been characterized across the two-photon absorption (TPA) transmission window. The results show that the TPA parameters in germanium waveguides are much stronger than the peak values in silicon, in good agreement with selected measurements conducted in bulk materials. Exploiting the large nonlinear absorption near the bandedge, efficient all-optical modulation is achieved with a modulation depth of ∼8  dB and a response time <5  ps.

Mid-infrared all-optical modulation in low-loss germanium-on-silicon waveguides

All-optical modulation has been demonstrated in a germanium-on-silicon rib waveguide over the mid-infrared wavelength range of 2-3 μm using a free-carrier absorption scheme. Transmission measurements have shown the waveguides to have low propagation losses that are relatively independent of wavelength out to 3.8 μm, indicating that the modulation could be extended further into the mid-infrared region for applications in sensing and spectroscopy. By monitoring the material recovery, the free-carrier lifetime of the micron-sized waveguides has been estimated to be ∼18  ns, allowing for modulation speeds within the megahertz regime.

Mid-infrared wavelength division (de)multiplexer using an interleaved angled multimode interferometer on the silicon-on-insulator platform

A low-cost and high-performance wavelength division (de)multiplexing structure in the mid-IR wavelength range is demonstrated on the silicon-on-insulator platform using an interleaved angled multimode interferometer (AMMI). As compared to a single AMMI, the channel count was doubled and the channel spacing halved with negligible extra insertion loss and crosstalk and with only a slight increase in device footprint. The device requires only single lithography and etching steps for fabrication. Potential is also shown for achieving improved performance with further optimized design.

Functional properties of human ferroportin, a cellular iron exporter reactive also with cobalt and zinc

Iron homeostasis is achieved by regulating the intestinal absorption of the metal and its recycling by macrophages. Iron export from enterocytes or macrophages to blood plasma is thought to be mediated by ferroportin under the control of hepcidin. Although ferroportin was identified over a decade ago, little is understood about how it works. We expressed in Xenopus oocytes a human ferroportin-enhanced green fluorescent protein fusion protein and observed using confocal microscopy its exclusive plasma-membrane localization. As a first step in its characterization, we established an assay to detect functional expression of ferroportin by microinjecting oocytes with (55)Fe and measuring efflux. Ferroportin expression increased the first-order rate constants describing (55)Fe efflux up to 300-fold over control. Ferroportin-mediated (55)Fe efflux was saturable, temperature-dependent (activation energy, Ea ≈ 17 kcal/mol), maximal at extracellular pH ≈ 7.5, and inactivated at extracellular pH < 6.0. We estimated that ferroportin reacts with iron at its intracellular aspect with apparent affinity constant < 10(-7) M. Ferroportin expression also stimulated efflux of (65)Zn and (57)Co but not of (64)Cu, (109)Cd, or (54)Mn. Hepcidin treatment of oocytes inhibited efflux of (55)Fe, (65)Zn, and (57)Co. Whereas hepcidin administration in mice resulted in a marked hypoferremia within 4 h, we observed no effect on serum zinc levels in those same animals. We conclude that ferroportin is an iron-preferring cellular metal-efflux transporter with a narrow substrate profile that includes cobalt and zinc. Whereas hepcidin strongly regulated serum iron levels in the mouse, we found no evidence that ferroportin plays an important role in zinc homeostasis.

Infestation of Tunga penetrans in villages near Zomba Central Hospital

An outbreak of Tunga Penetrans (Jigger Flea) infestation affecting a number of villages near to a Central Hospital in Malawi is described. Due to the large number of affected individuals, high parasitic load, and extended duration of infection an alternative to the recommended approach of surgical removal of the flea was required. Benzyl benzoate paint and liquid paraffin had been used in local Primary Healthcare settings previously and topical treatment with antiparasitic agents has been advocated in the literature, particularly for severe infestation. Benzyl benzoate and liquid paraffin were applied topically to four adults with numerous jigger flea burrows, and their progress assessed regularly. After completion of 7 days of treatment patients noted that fleas were dislodging spontaneously, and that embedded parasites had not increased in size to the same extent that untreated fleas had in previous infestations. Following confirmation of the viability of its implementation in a resource-poor setting, this treatment regimen has subsequently been adopted by the local branch of the District Health Office for distribution to infected communities.

Zip14 is a complex broad-scope metal-ion transporter whose functional properties support roles in the cellular uptake of zinc and nontransferrin-bound iron

Recent studies have shown that overexpression of the transmembrane protein Zrt- and Irt-like protein 14 (Zip14) stimulates the cellular uptake of zinc and nontransferrin-bound iron (NTBI). Here, we directly tested the hypothesis that Zip14 transports free zinc, iron, and other metal ions by using the Xenopus laevis oocyte heterologous expression system, and use of this approach also allowed us to characterize the functional properties of Zip14. Expression of mouse Zip14 in RNA-injected oocytes stimulated the uptake of (55)Fe in the presence of l-ascorbate but not nitrilotriacetic acid, indicating that Zip14 is an iron transporter specific for ferrous ion (Fe(2+)) over ferric ion (Fe(3+)). Zip14-mediated (55)Fe(2+) uptake was saturable (K(0.5) ≈ 2 μM), temperature-dependent (apparent activation energy, E(a) = 15 kcal/mol), pH-sensitive, Ca(2+)-dependent, and inhibited by Co(2+), Mn(2+), and Zn(2+). HCO(3)(-) stimulated (55)Fe(2+) transport. These properties are in close agreement with those of NTBI uptake in the perfused rat liver and in isolated hepatocytes reported in the literature. Zip14 also mediated the uptake of (109)Cd(2+), (54)Mn(2+), and (65)Zn(2+) but not (64)Cu (I or II). (65)Zn(2+) uptake also was saturable (K(0.5) ≈ 2 μM) but, notably, the metal-ion inhibition profile and Ca(2+) dependence of Zn(2+) transport differed from those of Fe(2+) transport, and we propose a model to account for these observations. Our data reveal that Zip14 is a complex, broad-scope metal-ion transporter. Whereas zinc appears to be a preferred substrate under normal conditions, we found that Zip14 is capable of mediating cellular uptake of NTBI characteristic of iron-overload conditions.

A pilot study on iodine in soils of Greater Kabul and Nangarhar provinces of Afghanistan

A robust and rapid methodology for the determination of iodine by inductively coupled plasma mass spectrometry in environmental samples is presented. Data were initially obtained for the validation of the analytical measurements, using 17 commercially available soil reference materials. The methodology was then tested on soil and water samples collected in Afghanistan where iodine deficiency and its effects are reportedly prevalent. Sample collections were conducted in Greater Kabul; the iodine in agricultural soils was determined to be in the range of 1.6-4.2 mg/kg and that in water drawn for drinking and irrigation was found to range from 9.9 to 22.7 microg/L. Samples were also collected in a second region, Nangarhar province, which is located to the east of Kabul, where goitres in the local population had been reported. The iodine content in soils and water at this location was 0.5-1.9 mg/kg and 5.4-9.4 microg/L, respectively. The organic content of soils in Kabul was found to be in the range of 1.9-4.2%; in Nangarhar, organic content ranged from 1.7 to 4.5%. All of the Afghan soils were slightly alkaline at pH 7.6-8.2.

Saturn's Spokes: Lost and Found

The spokes are intermittently appearing radial markings in Saturn's B ring that are believed to form when micrometer-sized dust particles are levitated above the ring by electrostatic forces. First observed by the Voyagers, the spokes disappeared from October 1998 until September 2005, when the Cassini spacecraft saw them reappear. The trajectories of the charged dust particles comprising the spokes depend critically on the background plasma density above the rings, which is a function of the solar elevation angle. Because the rings are more open to the Sun now than when Voyager flew by, the charging environment above the rings has prevented the formation of spokes until very recently. We show that this notable effect is capable of stopping spoke formation entirely and restricting the size of the particles in the spokes.

Bacterial translocation studied in 927 patients over 13 years

BACKGROUND

Bacterial translocation (BT) describes the passage of bacteria from the gastrointestinal tract to normally sterile tissues such as the mesenteric lymph nodes (MLNs) and other internal organs. The clinical and pathophysiological significance of BT remains controversial. This report describes results obtained over a 13-year period of study.

METHODS

MLNs were obtained from 927 patients undergoing laparotomy. Nasogastric aspirates were obtained from 458 (49.4 per cent) of 927 patients for culture; pH was measured in 172 (37.6 per cent) of 458. Preoperative clinical variables were evaluated and factors that influenced BT were included in a multivariate logistic regression analysis.

RESULTS

BT was identified in 130 (14.0 per cent) of 927 patients. Postoperative sepsis was more common in patients with BT (42.3 versus 19.9 per cent; P < 0.001). Independent preoperative variables associated with BT were emergency surgery (P = 0.001) and total parenteral nutrition (TPN) (P = 0.015). Gastric colonization was confirmed in 248 (54.1 per cent) of 458 patients, and was associated with both BT (P = 0.015) and postoperative sepsis (P = 0.029). A gastric pH of less than 4 was associated with a significant reduction in gastric colonization (53 versus 80 per cent; P < 0.001) and postoperative sepsis (46 versus 70.3 per cent; P = 0.018) but not BT.

CONCLUSION

BT is associated with postoperative sepsis. Emergency surgery and TPN are independently associated with an increased prevalence of BT.

Evaluation of a triple sugar test of colonic permeability in humans

AIM

Conventional dual sugar tests of intestinal permeability assess only the stomach and small intestine. A novel triple sugar method of assessing colonic permeability has recently been described in animals. This utilizes the non-fermented sweetener sucralose, in addition to conventional sugars. It has been postulated that this test enables the simultaneous assessment of small-intestinal and colonic barrier function in humans. The aim of this study was to evaluate the triple sugar test using healthy volunteers and ileostomists.

METHODS

Twenty-one healthy volunteers and 18 ileostomists underwent the triple sugar test. After an overnight fast, subjects drank a solution containing lactulose (5 g), rhamnose (1 g) and sucralose (5 g). Urine was collected for 0-5 h and 5-19 h. Urinary sugars were quantified using HPLC, and 5 and 24-h excretion calculated. Nineteen control subjects and 16 ileostomists also underwent a 51Cr-EDTA permeability test. Permeability data were presented as medians (IQR), and differences between groups analysed with Mann-Whitney U-tests.

RESULTS

Lactulose excretion and the 5-h lactulose/rhamnose (L/R) ratio were similar in controls and ileostomists [L/R ratio 0.024 (0.022-0.034) vs. 0.025 (0.022-0.035), P = 0.955]. Twenty-four hours excretion of sucralose was significantly higher in control subjects compared with ileostomists [1.41% (1.17-1.68) vs. 0.96% (0.64-1.2), P = 0.003]. The same pattern was seen with 51Cr-EDTA [2.73% (2.06-3.76) vs. 2.06% (1.55-2.71), P = 0.037] and with lactulose [0.52% (0.42-0.60) vs. 0.25% (0.16-0.35), P = 0.002].

CONCLUSIONS

Both sucralose and 51Cr-EDTA underwent significant colonic absorption. A significant amount of lactulose also appeared to be absorbed in the colon. This unexpected finding requires further study.

Randomized clinical trial of multimodal optimization and standard perioperative surgical care

BACKGROUND

Multimodal optimization of surgical care has been associated with reduced hospital stay and improved physical function. The aim of this randomized trial was to compare multimodal optimization with standard care in patients undergoing colonic resection.

METHODS

Twenty-five patients requiring elective right or left hemicolectomy were randomized to receive a ten-point optimization programme (14 patients) or conventional care (11). The groups were similar in terms of age (64 versus 68 years), male : female sex ratio (6 : 8 versus 5 : 6) and Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) score (both 26). Outcome measures were recorded before operation and on postoperative days 1, 7 and 30. They included hand grip strength, lung spirometry, and pain and fatigue scores. Further outcome measures included time to achieve a predetermined mobilization target, time to resumption of normal diet, and length of stay.

RESULTS

Optimization was associated with maintained grip strength, earlier mobilization (46 versus 69 h; P = 0.043), and significantly lower pain and fatigue scores. Patients in the optimization group tolerated a regular hospital diet significantly earlier than controls (48 versus 76 h; P < 0.001). Optimization significantly reduced the median length of hospital stay (3 versus 7 days; P = 0.002).

CONCLUSION

Optimization of surgical care significantly improved patients' physical and psychological function in the early postoperative period and facilitated early hospital discharge.

Gastric colonisation, intestinal permeability and septic morbidity in acute pancreatitis

INTRODUCTION

Bacterial translocation (BT) may represent an important cause of septic morbidity in patients with acute pancreatitis. We have previously demonstrated an association between BT, septic morbidity and colonisation of the proximal GI tract. Alterations in intestinal permeability (IP) may also predispose to BT. The aim of this study was to assess the extent of gastric colonisation, measure IP in patients with acute pancreatitis and relate these to both disease severity and septic complications.

METHODS

Gastric colonisation was determined by culturing a sample of nasogastric aspirate, and IP was measured using a dual sugar probe technique (lactulose/rhamnose test). Disease severity was assessed according to the modified Glasgow (Imrie) criteria. All septic complications were recorded prospectively.

RESULTS

A total of 59 patients were studied (M:F ratio 32:27, median age 66 years, range 18-89), 24 (31%) of whom had severe disease. A nasogastric aspirate was obtained in 56 patients. There was a significantly higher incidence of colonisation with potentially pathogenic enteric bacteria in patients with severe disease compared to those with mild disease (57 vs. 6%, p < 0.001). Septic morbidity occurred in 29% of severe patients and 11% mild patients (p = 0.17). 33% of patients colonised with enteric organisms developed sepsis, compared to 16% with no enteric bacteria in the NG aspirate (p = 0.34). Enteric bacteria caused 77% of the septic complications. Intestinal permeability was neither associated with disease severity nor was it predictive of septic morbidity.

CONCLUSIONS

There is significantly higher incidence of gastric colonisation with enteric bacteria in patients with severe acute pancreatitis, but no difference in IP. Enteric bacteria were implicated in the majority of septic complications. These findings support the gut origin of sepsis hypothesis in acute pancreatitis.

A prospective randomised study of the probiotic Lactobacillus plantarum 299V on indices of gut barrier function in elective surgical patients

BACKGROUND

Bacterial translocation occurs in surgical patients and may predispose to postoperative septic morbidity. Many factors are thought to influence the prevalence of bacterial translocation, one of which is the composition of the gut microflora. The aim of this prospective and randomised study was to assess the effect of the probiotic Lactobacillus plantarum 299v on the incidence of bacterial translocation, gastric colonisation, and septic complications in elective surgical patients.

METHODS

Patients undergoing elective major abdominal surgery were randomised to either a treatment or control group. The treatment group received an oral preparation containing Lactobacillus plantarum 299v (Proviva) for at least one week preoperatively and also in the postoperative period. Bacterial translocation was determined by culture of a mesenteric lymph node and serosal scraping obtained at laparotomy. Gastric colonisation was assessed by microbiological culture of nasogastric aspirates. All postoperative septic complications were recorded.

RESULTS

A total of 129 patients completed the study (probiotic group n=64). There was no significant difference between the two groups in terms of bacterial translocation (12% v 12%; p=0.82), gastric colonisation with enteric organisms (11% v 17%; p=0.42), or septic morbidity (13% v 15%; p=0.74).

CONCLUSIONS

Administration of Lactobacillus plantarum 299v in elective surgical patients does not influence the rate of bacterial translocation, gastric colonisation, or incidence of postoperative septic morbidity.

Evidence for selective coupling of alpha 1-adrenergic receptors to phospholipase C-beta 1 in rat neonatal cardiomyocytes

Activation of phospholipase C (PLC) in neonatal rat cardiomyocytes (NCM) generates primarily inositol 1,4,5-trisphosphate (Ins(1,4,5)P(3)) in response to rises in intracellular Ca(2+), or inositol 1,4-bisphosphate (Ins(1,4)P(2)) in response to norepinephrine (NE) (Matkovich, S. J. and Woodcock, E. A. (2000) J. Biol. Chem. 275, 10845-10850). To examine the PLC subtype mediating the alpha(1)-adrenergic receptor response, PLC-beta(1) and PLC-beta(3) were overexpressed in NCM using adenoviral infection (Ad-PLC-beta(1) NCM and Ad-PLC-beta(3) NCM, respectively) and PLC responses assessed from [(3)H]inositol phosphate (InsP) generation in the presence of 10 mm LiCl. The [(3)H]InsP response to NE (100 microm) was enhanced in Ad-PLC-beta(1) NCM relative to cells infected with blank virus (Ad-MX NCM), but was reduced in Ad-PLC-beta(3) NCM. In contrast, the [(3)H]InsP response to ATP (100 microm) was not elevated in Ad-PLC-beta(1) NCM, and was enhanced rather than diminished in Ad-PLC-beta(3) NCM, showing that effects of the two PLC-beta isoforms were specific for particular receptor types. PLC-delta(1) overexpression selectively reduced NE-induced [(3)H]InsP responses, without affecting the ATP stimulation. The reduced NE response was associated with a selective loss of PLC-beta(1) expression in Ad-PLC-delta(1) NCM. alpha(1)-Adrenergic receptor activation caused phosphorylation of PLC-beta(1) but not PLC-beta(3), whereas stimulation by ATP induced phosphorylation of PLC-beta(3) but not PLC-beta(1.) Taken together, these studies provide evidence that NE-stimulated InsP generation in NCM is primarily mediated by PLC-beta(1), despite the presence of both PLC-beta(1) and PLC-beta(3) isoforms.

Detection of eastern equine encephalitis virus in infected mosquitoes using a monoclonal antibody-based antigen-capture enzyme-linked immunosorbent assay

Surveillance of mosquito populations for virus activity is not often performed by small, vector-control districts because they do not have the financial resources to use virus isolation, or newer methods such as the polymerase chain reaction. Consequently, development and refinements of rapid, sensitive, and simple enzyme-linked immunosorbent assays (ELISAs) applicable to a wide variety of public health settings are justified. We have developed an antigen-capture ELISA for the detection of eastern equine encephalitis (EEE) virus in mosquitoes that uses both monoclonal capture and detector antibodies. The sensitivity of this assay is 4.0-5.0 log10 plaque-forming units/ml, which is comparable to previously published EEE antigen-capture assays developed with polyclonal antibody reagents. This test identifies only North American strains of EEE virus and does not react with either western equine encephalitis or Highlands J viruses. Test sensitivity was enhanced by sonicating mosquito pools, treating them with Triton X-100, and increasing the time and temperature of antigen incubation. The conversion of this ELISA to a monoclonal antibody-based format should result in a readily standardizable and transferable assay that will permit laboratories lacking virus isolation facilities to conduct EEE virus surveillance.

Bacterial translocation and immunohistochemical measurement of gut immune function

AIMS

The local immune response in the small bowel mucosa might play a role in bacterial translocation (BT). The aim of this study was to quantify immune cells and secretory antibodies in the small bowel mucosa, and relate this to BT as assessed by culture of a mesenteric lymph node.

METHODS

Immunohistochemical techniques were used to measure the frequency of plasma cells and IgA and IgM positive cells in the lamina propria and semiquantitatively to assess mucosal surface IgA and IgM values in small bowel specimens obtained from 11 patients in whom positive evidence of BT had been identified in a mesenteric lymph node harvested at the time of laparotomy. These were compared with similar specimens obtained from 11 patients in whom a similar lymph node had yielded no growth.

RESULTS

BT was associated with a significantly increased median frequency of plasma cells (p < 0.01) and IgA positive cells (p < 0.05) in the lamina propria. The frequency of IgM positive cells was also higher in these patients, although this difference was not significant. In addition, semiquantitatively scored IgA and IgM concentrations at the mucosal surface were both significantly higher in the patients in whom BT had been identified (p = 0.006 and 0.016, respectively).

CONCLUSION

Higher numbers of plasma cells and higher IgA and IgM values are present in the small bowel mucosa of patients in whom BT has been shown to occur, suggesting an increased local immune response.

Phospholipase C-gamma mediates the hydrolysis of phosphatidylinositol, but not of phosphatidylinositol 4,5-bisphoshate, in carbamylcholine-stimulated islets of langerhans

In pancreatic islets the activation of phospholipase C (PLC) by the muscarinic receptor agonist carbamyolcholine (carbachol) results in the hydrolysis of both phosphatidylinositol 4,5-bisphosphate (PtdInsP(2)) and phosphatidylinositol (PtdIns). Here we tested the hypothesis that PtdIns hydrolysis is mediated by PLCgamma1, which is known to be regulated by activation of tyrosine kinases and PtdIns 3-kinase. PtdIns breakdown was more sensitive than that of PtdInsP(2) to the tyrosine kinase inhibitor, genistein. Conversely, the tyrosine phosphatase inhibitor, vanadate, alone promoted PtdIns hydrolysis and acted non-additively with carbachol. Vanadate did not stimulate PtdInsP(2) breakdown. Carbachol also stimulated a rapid (maximal at 1-2 min) tyrosine phosphorylation of several islet proteins, although not of PLCgamma1 itself. Two structurally unrelated inhibitors of PtdIns 3-kinase, wortmannin and LY294002, more effectively attenuated the hyrolysis of PtdIns compared with PtdInsP(2). Adenovirally mediated overexpression of PLCgamma1 significantly increased carbachol-stimulated PtdIns hydrolysis without affecting that of PtdInsP(2). Conversely overexpression of PLCbeta1 up-regulated the PtdInsP(2), but not PtdIns, response. These results indicate that the hydrolysis of PtdIns and PtdInsP(2) are independently regulated in pancreatic islets and that PLCgamma1 selectively mediates the breakdown of PtdIns. The activation mechanism of PLCgamma involves tyrosine phosphorylation (but not of PLCgamma directly) and PtdIns 3-kinase. Our findings point to a novel bifurcation of signaling pathways downstream of muscarinic receptors and suggest that hydrolysis of PtdIns and PtdInsP(2) might serve different physiological ends.

West Nile virus recombinant DNA vaccine protects mouse and horse from virus challenge and expresses in vitro a noninfectious recombinant antigen that can be used in enzyme-linked immunosorbent assays

Introduction of West Nile (WN) virus into the United States in 1999 created major human and animal health concerns. Currently, no human or veterinary vaccine is available to prevent WN viral infection, and mosquito control is the only practical strategy to combat the spread of disease. Starting with a previously designed eukaryotic expression vector, we constructed a recombinant plasmid (pCBWN) that expressed the WN virus prM and E proteins. A single intramuscular injection of pCBWN DNA induced protective immunity, preventing WN virus infection in mice and horses. Recombinant plasmid-transformed COS-1 cells expressed and secreted high levels of WN virus prM and E proteins into the culture medium. The medium was treated with polyethylene glycol to concentrate proteins. The resultant, containing high-titered recombinant WN virus antigen, proved to be an excellent alternative to the more traditional suckling-mouse brain WN virus antigen used in the immunoglobulin M (IgM) antibody-capture and indirect IgG enzyme-linked immunosorbent assays. This recombinant antigen has great potential to become the antigen of choice and will facilitate the standardization of reagents and implementation of WN virus surveillance in the United States and elsewhere.

Enteral versus parenteral nutrition: a pragmatic study

Controversy persists as to the optimal means of providing adjuvant nutritional support. The aim of this study was to compare enteral nutrition (EN) and parenteral nutrition (TPN) in terms of adequacy of nutritional intake, septic and nonseptic morbidity, and mortality. This was a prospective pragmatic study, whereby the route of delivery of nutritional support was determined by the attending clinician's assessment of gastrointestinal function. Patients considered to have inadequate gastrointestinal function were given TPN (group 1), while those deemed to have a functioning gastrointestinal tract received EN (group 2). Patients in whom there was reasonable doubt as to the adequacy of intestinal function were randomized to receive either TPN (group 3) or EN (group 4). The trial setting was a large district general hospital with a dedicated nutrition team. A total of 562 patients were included in the study (331 males; median age 67 y). Gastrointestinal function on entry into the study was considered inadequate in 267 patients who were given TPN (group 1) and adequate in 231 whom received EN (group 2). There was clinical uncertainty about the adequacy of gut function in 64 patients (11.4%) who were randomized to receive either TPN (group 3, 32 patients) or EN (group 4, 32 patients). The incidence of inadequate nutritional intake was significantly higher in group 4 compared with group 3 (78.1% versus 25%, P < 0.001). Complications related to the delivery system and other feed-related morbidity were significantly more frequent in both EN groups compared with the respective TPN groups. EN was associated with a higher overall mortality in both nonrandomized and randomized patients. There were no significant differences observed in the incidences of septic morbidity between patients receiving TPN and those given EN. EN is associated with a higher incidence of inadequate nutritional intake, complications related to the delivery system, and other feed-related morbidity than TPN. There is no evidence from this study to support a difference between the two modalities in terms of septic morbidity. Patients in whom there is reasonable doubt as to the adequacy of gastrointestinal function should be fed by the parenteral route.

West Nile virus isolates from mosquitoes in New York and New Jersey, 1999

An outbreak of encephalitis due to West Nile (WN) virus occurred in New York City and the surrounding areas during 1999. Mosquitoes were collected as part of a comprehensive surveillance program implemented to monitor the outbreak. More than 32,000 mosquitoes representing 24 species were tested, and 15 WN virus isolates were obtained. Molecular techniques were used to identify the species represented in the WN virus-positive mosquito pools. Most isolates were from pools containing Culex pipiens mosquitoes, but several pools contained two or more Culex species.

Rapid detection of west nile virus from human clinical specimens, field-collected mosquitoes, and avian samples by a TaqMan reverse transcriptase-PCR assay

The authors report on the development and application of a rapid TaqMan assay for the detection of West Nile (WN) virus in a variety of human clinical specimens and field-collected specimens. Oligonucleotide primers and FAM- and TAMRA-labeled WN virus-specific probes were designed by using the nucleotide sequence of the New York 1999 WN virus isolate. The TaqMan assay was compared to a traditional reverse transcriptase (RT)-PCR assay and to virus isolation in Vero cells with a large number ( approximately 500) of specimens obtained from humans (serum, cerebrospinal fluid, and brain tissue), field-collected mosquitoes, and avian tissue samples. The TaqMan assay was specific for WN virus and demonstrated a greater sensitivity than the traditional RT-PCR method and correctly identified WN virus in 100% of the culture-positive mosquito pools and 98% of the culture-positive avian tissue samples. The assay should be of utility in the diagnostic laboratory to complement existing human diagnostic testing and as a tool to conduct WN virus surveillance in the United States.

Oral dietary supplements in pre- and postoperative surgical patients: a prospective and randomized clinical trial

It has been suggested that the routine provision of oral dietary supplements (ODS) in postoperative surgical patients is of benefit in terms of morbidity and length of hospital stay. The aim of this study was to evaluate the effects of both pre- and postoperative ODS in patients undergoing an elective laparotomy. Patients requiring elective major gastrointestinal surgery were prospectively randomized into one of four groups: Group I received ODS in addition to normal diet both pre- and postoperatively, Group II were given ODS in the preoperative period only, Group III received ODS only in the postoperative period, and Group IV did not receive any supplements. Assessments of nutritional status, voluntary food intake, weight loss, serum albumin, morbidity and mortality, anxiety and depression, and postoperative activity levels were performed, and comparisons made between the groups. One hundred patients were included in the study. The mean daily energy intake from preoperative ODS was 507 +/- 140 kcal, significantly more than the 252 +/- 195 kcal in the postoperative period (P < 0.001). The postoperative voluntary food intake in patients receiving ODS was not significantly different from that in patients receiving normal diet alone (1090 versus 1268 kcal, 46.2 versus 49.1 g protein, P > 0. 05). All groups demonstrated an overall weight loss, with no significant differences between the groups, and there was no demonstrable effect on clinical outcome. At 6 mo postoperatively there were no differences between the study groups in terms of levels of activity. These results suggest that the routine use of perioperative ODS in well-nourished patients undergoing major gastrointestinal surgery confers no clinical or functional benefit.

On Coquilleitidia crassipes, a new record for Macau, with a key to adults of the subgenera and species groups of the genus

Coquillettidia (Coquillettidia) crassipes is recorded for the 1st time in the Territory of Macau, southern China. The systematics of the genus is examined, new species groups are proposed, and a key to subgenera and species groups of Coquillettidia is provided.

The influence of endogenous dopamine levels on the density of [3H]SCH23390-binding sites in the brain of the honey bee, Apis mellifera L

This paper examines the relationship between endogenous dopamine (DA) levels and the density of [3H]SCH23390-binding sites in the brain of the adult worker honey bee. DA levels were reduced pharmacologically using a single 10 microl injection of either alpha-methyl-DL-p-tyrosine (AMT; 250 microg or 500 microg) or alpha-methyl-DL-tryptophan (AMTP; 250 or 500 microg) into the haemolymph of the bee. In all cases, maximum depletion of DA was observed 3 h after treatment, but in bees treated with AMTP (250 or 500 microg) or with 250 microg AMT, DA levels returned to normal within 24 h of treatment. Neither AMT nor AMTP was selective for DA: both drugs also reduced serotonin (5-hydroxytryptamine, 5HT) levels in the brain. However, AMTP was more effective than AMT at depleting 5HT, whereas for DA, the reverse was true. Depletion of DA levels, using 250 microg AMT, led to a dramatic decline in the levels of specific binding of [3H]SCH23390, defined in this study as binding in the presence of 5x10(-6) M cis-(Z)-flupentixol (see Ref. [28] ). In contrast, naturally occurring diel fluctuations in DA levels, identified in the optic lobes of the brain, and changes in brain DA levels resulting from queenlessness, had no significant effect on the density of [3H]SCH23390-binding sites in the brain of the bee. Overall, these results indicate that under normal physiological conditions, there is no direct link in honey bees between changes in endogenous brain DA levels and the density of D(1)-like receptors labelled by [3H]SCH23390.

Gut origin of sepsis: a prospective study investigating associations between bacterial translocation, gastric microflora, and septic morbidity

AIMS

To investigate the "gut origin of sepsis" hypothesis.

METHODS

Prospective controlled study of 279 surgical patients in which cultures of nasogastric aspirates were compared with those obtained from mesenteric lymph nodes taken at laparotomy and the organisms cultured from subsequent septic complications. Bacterial translocation was confirmed if positive cultures were obtained from mesenteric lymph nodes. Postoperative sepsis was defined as any positive culture in the postoperative period. Bacterial species obtained in gastric microflora, mesenteric lymph nodes, and postoperative septic complications were compared.

RESULTS

Only 85/279 patients (31%) had a sterile nasogastric aspirate; the most frequently identified organism was Candida spp. (54%) and the most common enteric organism cultured was E coli (20%). Multiple organisms were isolated in 39% and occurred more frequently in patients aged over 70 years, those undergoing non-elective surgery, and in those requiring proximal gastrointestinal surgery. Postoperative sepsis was more common in these patients. Bacterial translocation occurred in 21% and was significantly more frequent in those with multiple organisms in their nasogastric aspirates. E coli was the commonest organism isolated from the lymph node specimens (48%) and septic foci (53%). Fungal translocation did not occur. An identical genus was identified in the nasogastric aspirate and the septic focus in 30% of patients, in the nasogastric aspirate and the lymph node in 31%, and in the lymph node and a postoperative septic focus in 45%.

CONCLUSIONS

Proximal gut colonisation is associated with both increased bacterial translocation and septic morbidity. The commonality of organisms identified supports the gut origin of sepsis hypothesis.

Safety of pancreatic surgery in a small DGH

The Combined Gastroenterology Service at Scarborough Hospital has a particular interest in pancreatic disease. The claim that pancreatic surgery should only be performed in larger, specialised units prompted a review of our experience in a small district general hospital (DGH). The case notes of 63 patients who had undergone pancreatic surgery over a 7-year period were examined retrospectively. The 30-day mortality was 8%, while 14 complications were recorded. Of 16 patients with acute pancreatitis, three died before discharge and three had long-term complications. Five patients who underwent surgery for chronic pancreatitis were discharged safely. There were 11 curative and 29 palliative procedures for patients with malignant disease. Median survival was 8 months (range 1-32 months) and median hospital stay was 16.8 days (range 7-89 days). Successful pancreatic surgery can be performed safely in a DGH setting. Patient selection and expertise are more important than numbers.

Isolation of La Crosse, Cache Valley, and Potosi viruses from Aedes mosquitoes (Diptera: Culicidae) collected at used-tire sites in Illinois during 1994-1995

Prospective studies were conducted at used-tire sites in Illinois during 1994-1995 in an effort to isolate arboviruses from mosquitoes, particularly Aedes albopictus (Skuse) and Aedes triseriatus (Say). Three isolates of Potosi virus were obtained from Ae. albopictus collected at a waste tire site in Jasper County during 1994 and 1995. Also, a single isolate of Cache Valley virus was obtained from Ae. albopictus collected at the Jasper County site during 1995. These are the first records of arbovirus isolations from Ae. albopictus in Illinois and the first isolate of Cache Valley virus from this mosquito species. During 1994, two isolates of La Crosse virus were made from Ae. triseriatus collected at a used-tire site in Peoria County in proximity to the residence of a human La Crosse encephalitis case. This is the first evidence in Illinois that indicates increased risk to humans living near used-tire sites, which may serve as foci for production of Ae. triseriatus, the vector of La Crosse virus. Tire removal and improved environmental sanitation at such sites may greatly reduce the abundance of vector mosquitoes, and, therefore, the risk of arbovirus transmission.

A prospective study of serum pancreatic elastase-1 in the diagnosis and assessment of acute pancreatitis

BACKGROUND

Serum amylase gives a poor estimate of both the true incidence and the severity of acute pancreatitis (AP).

METHODS

We evaluated serum pancreatic elastase-1 (PE-1) prospectively in 567 patients in whom AP was suspected. In established AP, severity was assessed using the Glasgow Criteria, and C-reactive protein, amylase, and serum PE-1 were evaluated over 5 days.

RESULTS

The sensitivity, specificity, and diagnostic efficiency of serum PE-1 were 0.66, 0.85, and 0.84, respectively. The diagnostic accuracy of serum PE-1 was 0.80, and that of amylase 0.97. Serum PE-1 did not correlate with disease severity or the development of complications, but it fell more slowly than the serum amylase in the week after admission.

CONCLUSIONS

The serum PE-1 level correlated closely with the serum amylase but conferred no benefit as a diagnostic test, nor did it provide further prognostic information.

Alterations in intestinal barrier function do not predispose to translocation of enteric bacteria in gastroenterologic patients

Bacterial translocation from the intestinal lumen has been demonstrated in humans. Three mechanisms have been suggested to explain the phenomenon: altered intestinal barrier function, bacterial overgrowth, and impaired host defense. The aim of this study was to determine whether changes in intestinal barrier function assessed by measurement of intestinal permeability and morphology were associated with alteration in bacterial translocation. Intestinal permeability was assessed in 43 patients by the lactulose/L-rhamnose test with a 5-h urine collection. Mucosal atrophy was assessed from the villus height-to-mucosal thickness ratio in small-bowel biopsies. Bacterial translocation was determined by microbiologic analysis of harvested mesenteric lymph nodes. No significant differences were apparent in the incidence of bacterial translocation in patients with normal permeability (5 [23%] of 22 patients translocated) compared with patients with increased permeability (4 [19%] of 21 patients translocated). Similarly, no correlation was apparent between the incidence of bacterial translocation and the index of villus atrophy. The degree of villus atrophy failed to correlate with gastrointestinal permeability. These data suggest that the incidence of bacterial translocation is not related to increased intestinal permeability or mucosal atrophy.

Microbiology of bacterial translocation in humans

BACKGROUND

Gut translocation of bacteria has been shown in both animal and human studies. Evidence from animal studies that links bacteria translocation to the development of postoperative sepsis and multiple organ failure has yet to be confirmed in humans.

AIMS

To examine the spectrum of bacteria involved in translocation in surgical patients undergoing laparotomy and to determine the relation between nodal migration of bacteria and the development of postoperative septic complications.

METHODS

Mesenteric lymph nodes (MLN), serosal scrapings, and peripheral blood from 448 surgical patients undergoing laparotomy were analysed using standard microbiological techniques.

RESULTS

Bacterial translocation was identified in 69 patients (15.4%). The most common organism identified was Escherichia coli (54%). Both enteric bacteria, typical of indigenous intestinal flora, and non-enteric bacteria were isolated. Postoperative septic complications developed in 104 patients (23%). Enteric organisms were responsible in 74% of patients. Forty one per cent of patients who had evidence of bacterial translocation developed sepsis compared with 14% in whom no organisms were cultured (p < 0.001). Septic morbidity was more frequent when a greater diversity of bacteria resided within the MLN, but this was not statistically significant.

CONCLUSION

Bacterial translocation is associated with a significant increase in the development of postoperative sepsis in surgical patients. The organisms responsible for septic morbidity are similar in spectrum to those observed in the mesenteric lymph nodes. These data strongly support the gut origin hypothesis of sepsis in humans.

Independent effects of palatability and within-meal pauses on intake and appetite ratings in human volunteers

The effects of the introduction of timed pauses within meals and palatability on food intake and changes in rated appetite during a meal were assessed in three experiments in which volunteers ate a lunch of pasta with a tomato sauce. Eating was monitored using a disguised electronic balance attached to a micro-computer, which also allowed the introduction of timed pauses within meals. In the first experiment, 16 subjects were tested with both a bland and palatable food (with 0.27% oregano), with eating uninterrupted or with pauses after every 50 g consumed during which appetite ratings were completed. Both the addition of oregano and the introduction of regular within-meal pauses enhanced overall intake. Rated hunger increased in the early stages of eating the palatable food in the interrupted condition, and then declined, whereas hunger declined throughout with the bland food. Similarly, the linear function relating intake to time in the uninterrupted condition was greater with the palatable food. In the second experiment, nine subjects ate the palatable food with no pauses within meals, with 30-second pauses with appetite ratings or with 30-second pauses in a non-appetite task. Intake was greater in both pause conditions than when eating was uninterrupted. In Experiment 3, the effect of pause duration was investigated in a further 16 subjects, with either no pause or a pause of 5, 30 or 60 seconds. Subjects ate more in all pause conditions than with no pauses, while ratings of hunger and fullness suggested that subjects were less satisfied at the end of the meal with longer pauses. These data confirm previous work which suggests that palatability exerts its effect by stimulating appetite and eating rate, but also suggest that the introduction of pauses within meals enhances intake as well, contradicting the idea that pausing within meals should reduce intake by allowing more time for post-ingestive satiety to develop.

Epidemiological typing of coagulase-negative staphylococci from nosocomial infections

Biotyping, antibiograms, bacteriophage typing, plasmid profile analysis and SDS-PAGE protein profiles were used to determine the relatedness of 44 Staphylococcus epidermidis and four S. haemolyticus isolates from 14 patients. A selection of these were further characterised by ribotyping. Biotyping classified the isolates into three major groups but was considered a poor strain marker. Although antibiograms classified the S. epidermidis isolates into 20 groups, some changes in the susceptibility patterns of related isolates from a single patient were demonstrated. Bacteriophage typing was the least discriminatory of the methods used. SDS-PAGE gave highly related patterns for the majority of S. epidermidis isolates. Plasmid profile analysis and ribotyping, with a minimum of two restriction endonucleases, were the most discriminatory methods for typing S. epidermidis. Nonetheless, some isolates from the same patient - probably representing a single strain - varied in plasmid profile indicating plasmid instability. One of six related isolates from a single patient lacked two bands from the ribotyping pattern of the other isolates. Although no single method proved entirely satisfactory on all occasions, the combination of typing methods was sufficient to provide evidence of the relatedness of S. epidermidis isolates from individual patients.

Aedes albopictus in the United States: ten-year presence and public health implications

Since its discovery in Houston, Texas, in 1987, the Asian "tiger mosquito" Aedes albopictus has spread to 678 counties in 25 states. This species, which readily colonizes container habitats in the peridomestic environment, was probably introduced into the continental United States in shipments of scrap tires from northern Asia. The early pattern of dispersal followed the interstate highway system, which suggests further dispersal by human activities. The Public Health Service Act of 1988 requires shipments of used tires from countries with Ae. albopictus to be treated to prevent further importations. Given the extensive spread of the mosquito in the United States, it is questionable whether such a requirement is still justified. Ae. albopictus, a major biting pest throughout much of its range, is a competent laboratory vector of at least 22 arboviruses, including many viruses of public health importance. Cache Valley and eastern equine encephalomyelitis viruses are the only human pathogens isolated from U.S. populations of Ae. albopictus. There is no evidence that this mosquito is the vector of human disease in the United States.

Administration of peripheral parenteral nutrition: a prospective study comparing rotation of venous access sites with ultrafine cannulas

Peripheral veins have been used successfully for patients requiring short- to medium-term total parenteral nutrition. This study prospectively compares two methods of peripheral parenteral nutrition (PPN). Forty-six patients requiring parenteral nutrition (PN) were identified prospectively. Fifty courses of PPN were prescribed using a standardized PPN formula of 9.3 g nitrogen, 1400 kCal, 2500 ml (KABI II, Pharmacia). Patients were randomized to receive PPN via 23G, 15 cm flexane catheters (Nutriline) inserted into an antecubital vein which remained in-situ with a continuous infusion over 24 h, or to receive 12-h cyclical infusions through peripherally sited 18G catheters (Venflon) which were removed postinfusion and reinserted into the contralateral forearm on alternate days. Data collected included duration, complications and cost of materials for each prescribed course. A scoring system to determine patient anxiety and depression and a questionnaire regarding patients' perspectives were evaluated. Fifty courses were prescribed, 26 by rotation of veins (RV) and 24 by Nutriline (N). Mean duration of feeding was 7.9 and 8.6 days, respectively; cost of materials were comparable 6.48/day (RV) vs 5.17/day (N); 2 RV patients failed to complete their course (no access [P< 0.05], whilst 9 N patients failed to complete their course (4 severe phlebitis, 2 no venous access, 2 septicaemia, 1 dislodged). Five patients required CPN (RV, N 3) while 4 remaining patients were fed by an alternative PPN method. The overall incidence of anxiety was 20% and of depression 16%, with no significant difference between groups. The majority of patients (87%) found mobility restricted. Twelve-hourly infusions via alternate forearm veins were significantly more successful than continuous infusions via Nutriline, both in terms of completion of the prescribed course and less venous morbidity. This study confirms that rotation of forearm veins allows affordable and successful PN administration to the majority of patients, with low PN-related morbidity.

Prospective study of the aetiology of infusion phlebitis and line failure during peripheral parenteral nutrition

Four techniques of administering peripheral parenteral nutrition (PPN) were examined prospectively to investigate the role of mechanical trauma in the development of infusion phlebitis. Patients in group 1 (n = 15) were fed via a standard 18-G Teflon cannula which was removed on completion of the infusion and was rotated to the contralateral arm every day. Group 2 patients (n = 15) had a similar catheter sited in each forearm simultaneously, with rotation of the side of infusion each day. Patients in group 3 (n = 17) had a 15-cm Silastic rubber catheter inserted into a forearm vein and a standard cannula sited in the contralateral forearm, with alternation of infusion each day. Those in group 4 (n = 13) had a fine-bore 23-G silicone catheter sited in one arm only. Patients in groups 1, 2 and 3 were fed over 12-h cycles and those in group 4 for a 24-h continuous cycle. A total of 408 patient-days of PPN were given. Mean duration of PPN in groups 1-4 was 7.5, 9, 5.5 and 5 days respectively. Infusion phlebitis was not recorded in patients who had a daily change of cannula (group 1), but occurred in four patients in group 2, eight in group 3 and eight in group 4. Phlebitis scores were 0, 9, 15 and 12 for groups 1-4 respectively. Severe phlebitis and line occlusion occurred more frequently in patients with a 15-cm catheter (group 3) and in those fed continuously over 24 h (group 4). These results suggest that mechanical trauma is an important factor in the aetiology of infusion phlebitis. This can be minimized by reducing the time for which the vein wall is exposed to nutrient infusion and by reducing the amount of prosthetic material within the vein.

Arbovirus titer variation in field-collected mosquitoes

Patterns in the distribution of titers in arbovirus-positive mosquito pools were examined. Virus isolation records from the Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, from 1974 through 1993 were used to estimate virus titers in field-collected pools. Pools were classified as either low titer (< or = 3.0 log10 plaque-forming units [PFU]/ml) or high titer (> 3.0 log10 PFU/ml). The proportion of virus-positive pools that had high titers varied among the different domestic arboviruses, within viruses among field sites and years, and within viruses among mosquito species tested. Alphaviruses produced a greater proportion of pools with high titers than did the flaviviruses. Variation in the proportion of pools with high titers among sites and years suggested variation in mosquito and/or virus strains. Variation in the proportion of pools with high titers among mosquito species indicated species-specific differences in vectorial capacity. The results show that information about the titer of virus in mosquito pools can complement other parameters, such as the minimum infection rate, currently used in mosquito-based arbovirus surveillance programs.