Quercetin and its major metabolites selectively modulate cyclic GMP-dependent relaxations and associated tolerance in pig isolated coronary artery

BACKGROUND AND PURPOSE

Quercetin is a major flavonoid that contributes to the reduced risk of cardiovascular disease associated with dietary ingestion of fruits and vegetables. We have pharmacologically characterized the effect of quercetin, and its sulphate and glucuronide metabolites, on vasoconstrictor and vasodilator responses in the porcine isolated coronary artery.

EXPERIMENTAL APPROACH

Segments of the porcine coronary artery were prepared for either isometric tension recording or determination of cyclic GMP content. The effect of quercetin and metabolites on submaximal responses to U46619 was examined in the presence and absence of substance P, bradykinin, forskolin, sodium nitroprusside (SNP) and glyceryl trinitrate (GTN).

KEY RESULTS

Quercetin and quercetin 3'-sulphate inhibited endothelin and U46619-induced contractions with greater potency (three- to fivefold) against the former, while quercetin 3-glucoronide was inactive. Quercetin enhanced both the cyclic GMP content of the artery (threefold) and cyclic GMP-dependent relaxations to GTN and SNP (two to threefold), but forskolin-induced relaxations were unaffected. Although the effect of quercetin was qualitatively similar to that noted for UK-114,542, a selective inhibitor of phosphodiesterase 5, it was still evident against SNP-induced relaxations in the presence of 10 nM UK-114,542. Quercetin and quercetin 3'-sulphate significantly reduced the development of GTN-associated 'tolerance'.

CONCLUSIONS AND IMPLICATIONS

Quercetin and quercetin 3'-sulphate inhibited receptor-mediated contractions of the porcine isolated coronary artery by an endothelium-independent action. Quercetin selectively enhanced cyclic-GMP-dependent relaxations by a mechanism not involving phosphodiesterase 5 inhibition. In addition, quercetin and quercetin 3'-sulphate opposed GTN-induced tolerance in vitro, which may be beneficial for patients treated for angina pectoris.

Evaluation of potassium iodide (KI) and ammonium perchlorate (NH4ClO4) to ameliorate 131I- exposure in the rat

Nuclear reactor accidents and the threat of nuclear terrorism have heightened the concern for adverse health risks associated with radiation poisoning. Potassium iodide (KI) is the only pharmaceutical intervention that is currently approved by the Food and Drug Administration for treating (131)I(-) exposure, a common radioactive fission product. Though effective, KI administration needs to occur prior to or as soon as possible (within a few hours) after radioactive exposure to maximize the radioprotective benefits of KI. During the Chernobyl nuclear reactor accident, KI was not administered soon enough after radiation poisoning occurred to thousands of people. The delay in administration of KI resulted in an increased incidence of childhood thyroid cancer. Perchlorate (ClO(4)(-)) was suggested as another pharmaceutical radioprotectant for 131I- poisoning because of its ability to block thyroidal uptake of iodide and discharge free iodide from the thyroid gland. The objective of this study was to compare the ability of KI and ammonium perchlorate to reduce thyroid gland exposure to radioactive iodide (131I-). Rats were dosed with 131I- tracer and 0.5 and 3 h later dosed orally with 30 mg/kg of either ammonium perchlorate or KI. Compared to controls, both anion treatments reduced thyroid gland exposure to 131I- equally, with a reduction ranging from 65 to 77%. Ammonium perchlorate was more effective than stable iodide for whole-body radioprotectant effectiveness. KI-treated animals excreted only 30% of the (131)I(-) in urine after 15 h, compared to 47% in ammonium perchlorate-treated rats. Taken together, data suggest that KI and ammonium perchlorate are both able to reduce thyroid gland exposure to 131I- up to 3 h after exposure to 131I-. Ammonium perchlorate may offer an advantage over KI because of its ability to clear 131I- from the body.

Report of Trichinella spiralis in a red fox (Vulpes vulpes) in Northern Ireland

No systematic studies of the occurrence of Trichinella in wildlife have been carried out in Northern Ireland (NI) in recent years, and the last reports of trichinellosis in livestock and human outbreaks in NI date back to 1979 and 1945, respectively. In this study, covering the period 2003/2004 and 2007/2008, a total of 443 red foxes (Vulpes vulpes) were collected throughout the country and screened for trichinellosis using a modified muscle digest method. One examined animal was found to be infected with larvae from Trichinella spiralis, indicating a national prevalence in NI of Trichinella in foxes of 0.2%. This prevalence compares well to the findings reported from the bordering Republic of Ireland [Rafter, P., Marucci, G., Brangan, P., Pozio, E., 2005. Rediscovery of Trichinella spiralis in red foxes (Vulpes vulpes) in Ireland after 30 years of oblivion. J. Infect. 50, 61-65] and could be a further indication for a sylvatic Trichinella life cycle existing independently from the domestic cycle.

Lower thyroid compensatory reserve of rat pups after maternal hypothyroidism: correlation of thyroid, hepatic, and cerebrocortical biomarkers with hippocampal neurophysiology

The developing central nervous system of the fetus and neonate is recognized as very sensitive to maternal or gestational hypothyroidism. Despite this recognition, there is still a lack of data concerning the relationship between thyroid-related biomarkers and neurological outcomes. We used propylthiouracil administered at 0, 3, or 10 ppm in drinking water from gestational d 2 until weaning to create hypothyroid conditions to study the relationship between hypothalamic-pituitary-thyroid axis compensation and impaired neurodevelopment. In addition to serum T(3), T(4), free T(4), and TSH concentrations, cerebrocortical T(3) concentration (cT(3)), hepatic type I and cerebrocortical type II (D2) 5'-deiodinase activity, and thyroidal mRNA for thyroglobulin and sodium iodide symporter were measured. Extracellular recordings from the CA1 region in hippocampal slices were obtained from both postnatal d 21-32 (pups) and postnatal d 90-110 (adults) rats to assess neurophysiological effects. Thyroidal mRNA for thyroglobulin and sodium iodide symporter were increased in pups but not in dams. Both propylthiouracil doses increased cerebrocortical D2 activity approximately 5-fold in pups but only 10 ppm increased D2 activity in dams. In dams, cT(3) concentrations were maintained at 3 ppm but fell 75% at 10 ppm. cT(3) concentration in pups fell 50% at 3 ppm and more than 90% at 10 ppm. In both 3 and 10 ppm pups, hippocampal baseline synaptic activity correlated negatively with cerebrocortical D2 activity. In 3 ppm adults, impaired long-term potentiation was evident. In summary, during depletion of serum T(4), D2 activity served as a sensitive marker of tissue thyroid status, an indicator of the brain's compensatory response to maintain cT(3), and correlated with a neurophysiological outcome.

A comparison of modifications of the McMaster method for the enumeration of Ascaris suum eggs in pig faecal samples

The comparative efficacies of seven published McMaster method modifications for faecal egg counting were evaluated on pig faecal samples containing Ascaris suum eggs. Comparisons were made as to the number of samples found to be positive by each of the methods, the total egg counts per gram (EPG) of faeces, the variations in EPG obtained in the samples examined, and the ease of use of each of the methods. Each method was evaluated after the examination of 30 samples of faeces. The positive samples were identified by counting A. suum eggs in one, two and three sections of newly designed McMaster chamber. In the present study compared methods were reported by: I-Henriksen and Aagaard [Henriksen, S.A., Aagaard, K.A., 1976. A simple flotation and McMaster method. Nord. Vet. Med. 28, 392-397]; II-Kassai [Kassai, T., 1999. Veterinary Helminthology. Butterworth-Heinemann, Oxford, 260 pp.]; III and IV-Urquhart et al. [Urquhart, G.M., Armour, J., Duncan, J.L., Dunn, A.M., Jennings, F.W., 1996. Veterinary Parasitology, 2nd ed. Blackwell Science Ltd., Oxford, UK, 307 pp.] (centrifugation and non-centrifugation methods); V and VI-Grønvold [Grønvold, J., 1991. Laboratory diagnoses of helminths common routine methods used in Denmark. In: Nansen, P., Grønvold, J., Bjørn, H. (Eds.), Seminars on Parasitic Problems in Farm Animals Related to Fodder Production and Management. The Estonian Academy of Sciences, Tartu, Estonia, pp. 47-48] (salt solution, and salt and glucose solution); VII-Thienpont et al. [Thienpont, D., Rochette, F., Vanparijs, O.F.J., 1986. Diagnosing Helminthiasis by Coprological Examination. Coprological Examination, 2nd ed. Janssen Research Foundation, Beerse, Belgium, 205 pp.]. The number of positive samples by examining single section ranged from 98.9% (method I), to 51.1% (method VII). Only with methods I and II, there was a 100% positivity in two out of three of the chambers examined, and FEC obtained using these methods were significantly (p<0.01) higher comparing to remaining methods. Mean FEC varied between 243 EPG (method I) and 82 EPG (method IV). Examination of all three chambers resulted in four methods (I, II, V and VI) having 100% sensitivity, while method VII had the lowest 83.3% sensitivity. Mean FEC in this case varied between 239 EPG (method I) and 81 EPG (method IV). Based on the mean FEC for two chambers, an efficiency coefficient (EF) was calculated and equated to 1 for the highest egg count (method I) and 0.87, 0.57, 0.34, 0.53, 0.49 and 0.50 for remaining methods (II-VII), respectively. Efficiency coefficients make it possible not only to recalculate and unify results of faeces examination obtained by any method but also to interpret coproscopical examinations by other authors. Method VII was the easiest and quickest but least sensitive, and method I the most complex but most sensitive. Examining two or three sections of the McMaster chamber resulted in increased sensitivity for all methods.

Control of the sheep scab mite Psoroptes ovis in vivo and in vitro using fungal pathogens

As part of a research programme designed to identify biological agents for the control of sheep scab, the pathogenicity of the fungus Metarhizium anisopliae to Psoroptes mites in the presence of sheepskin and wool was examined in the laboratory. No inhibitory effects of skin and wool were observed and high levels of infection were recorded. Subsequently the pathogenicity of formulations of both M. anisopliae and Beauveria bassiana to Psoroptes ovis was studied in vivo. For this, 36 batches of 20 adult female Psoroptes mites were confined in 25 mm diameter chambers which were attached to the backs of 6 scab-naive sheep. In some treatments, mites were exposed to the fungal pathogens for 48 h in vitro prior to being placed on the host, while other treatments involved mites with no prior exposure placed directly onto the skin of a host treated with a fungal pathogen. After 48 h on the host, mites were removed, incubated individually and all fungal infections were recorded. Fungal infection was observed in all treatments, except untreated controls. However, B. bassiana infected a significantly greater number of mites than M. anisopliae with all the formulations examined. Infection rates were highest when mites were exposed to dry conidia (>90%) and lowest with M. anisopliae in diatomaceous earth. Overall, the infection rate was not affected by whether or not the mites were given prior exposure to the conidia, before being placed on the sheep. The results demonstrate that Psoroptes mites can become infected by entomopathogenic fungi on the skin of sheep and provides a first demonstration of the potential of this technology for the control of sheep scab.

Analysis of Climatic Predictions for Extrinsic Incubation of Dirofilaria in The United Kingdom

Transmission of dirofilariasis in Europe is dependent upon the presence of sufficient numbers of infected dogs, susceptible mosquitoes, and a suitable climate to permit extrinsic incubation of Dirofilaria in the mosquito intermediate host. Dogs returning to the United Kingdom from overseas have been infected with several vector-borne infections (Babesia, Ehrlichia, Leishmania, and Dirofilaria), and this paper assesses the climatic constraints on the potential rate of extrinsic incubation of Dirofilaria in the United Kingdom. A model using an established algorithm based on accumulated temperature predicts that summer temperatures during 1995-2000 may have been sufficient to permit complete incubation of Dirofilaria in 2 of the years for large parts of southern/central England, and 5 years around London. The occurrence of autochthonous transmission would be dependent upon additional factors related to frequency of returning infected dogs and the distribution and abundance of putative mosquito vectors, and these should be studied further.

Resurrecting melancholia

OBJECTIVE

To define melancholia as a distinct mood disorder, identified by unremitting depressed mood, vegetative dysfunction, and psychomotor disturbances, verifiable by neuroendocrine tests, and treatable by electroconvulsive therapy and tricyclic antidepressants.

METHOD

A review of the literature of two centuries finds descriptions of severe mood disorders, either depression or mania or circular, defined as 'melancholia.' In the 1980 diagnostic revision (DSM-III), melancholia was relegated to a features specifier only.

RESULTS

DSM classification criteria develop heterogeneous patient samples that are neither guides to prognosis nor to treatment response, and confound studies of pathophysiology. Within the large population of mood disorders, a syndrome of melancholia is identifiable by specific behaviors, vegetative signs, and validated by neuroendocrine abnormalities (cortisolemia). Populations so identified are clinically homogeneous and have improved treatment responses. Patients meeting criteria for melancholia are now identified as psychotic depressed, geriatric depressed, postpartum psychosis, and pharmacotherapy resistant.

CONCLUSION

The review supports the establishment of melancholia by empirically derived criteria rather than by a checklist is an alternative to the major depression choice and offers an improved model for psychiatric classification.

Perioperative transfusion for pancreaticoduodenectomy and its impact on prognosis in resected pancreatic ductal adenocarcinoma

BACKGROUND AND AIMS

Pancreaticoduodenectomy (PD) is a major operative intervention performed most commonly for malignancy in the head of pancreas. The aim of this study was to evaluate the utilization of blood transfusion for PD and to determine whether this had prognostic significance in a subset of patients with pancreatic ductal adenocarcinoma (PDAC).

MATERIAL AND METHODS

Data on blood transfusion requirement were retrospectively collected for patients undergoing PD from 1998 to 2005. Standard prognostic factors and survival data were also collected in patients with PDAC.

RESULTS

One-hundred-and-seventy patients underwent PD. Seventy-six patients (45%) received transfusion. The median (interquartile range) number of units of red cell concentrate (RCC) transfused perioperatively (intraoperatively and within 24 h of surgery) was 1.5 (0.5-2.5). The median preoperative haemoglobin (Hb) was 126 g/dl. The median number of units of RCC transfused perioperatively in patients with Hb <126 g/dl was 2 (1-3); for those with Hb > or = 126 g/dl the median was 0 (0-1); p=0.003. Forty-nine patients who were resected for PDAC were subjected to survival analysis. Univariate and multivariate analyses showed that only posterior resection margin invasion was associated with an adverse outcome (margin positive 198 [143-470] days vs margin negative 398 [303-859] days; p=0.02). Perioperative RCC transfusion requirement was not a significant predictor of survival (transfusion 408 [214-769] days vs no transfusion 331 [217-391] days; p=0.18). Furthermore, RCC transfusion within 30 days of operation was not a significant predictor of poor survival (transfusion 331 [201-459] days vs no transfusion 317 [196-769] days; p=0.43).

CONCLUSIONS

PD can be performed with a moderately low requirement for RCC transfusion; however, low preoperative haemoglobin is a predictor for the requirement of RCC transfusion. Administration of RCC transfusion does not appear to be a significant adverse prognostic factor in patients with resected PDAC.

A computer model to simulate control of parasitic gastroenteritis in sheep on UK farms

A computer model that simulates the population dynamics and epidemiology of three major species of parasitic nematodes of sheep found in the UK (Telodorsagia [Ostertagia] spp., Haemonchus spp. and Trichostrongylus spp.) is described. The model has been developed as a tool for veterinarians and advisors to aid in the implementation of integrated parasite control strategies designed to optimise anthelmintic usage and delay the development of resistance on UK farms. The model represents the parasite life cycle, flock dynamics and the response of individuals with different susceptible and resistant genotypes to the major broad-spectrum classes of anthelmintic available in the UK. Where possible, UK data have been used for the model parameters. The model allows worm control simulations on individual UK farms. Inputs include environmental and farm management variables which impact on the epidemiology of the disease, e.g. regional weather data; flock stocking rates; initial pasture larval contamination levels and species proportions; lambing dates; timing of flock movements to clean pastures; and removal of lambs during the year. Farm management data, as well as nematode egg outputs and grass larval counts, were collected from eight UK farms over a 1-year period for initial validation of the model outputs. The management data for each farm were used as inputs for each model run and model outputs for nematode egg counts from ewes and lambs were compared to the observed data for each farm. Statistical analysis of results shows a positive correlation for observed and simulated counts and regression analysis suggests an acceptable fit between the data. Comparison of observed and simulated outputs for resistance were possible for only one farm due to low numbers of worms developing in the laboratory tests. Additional studies will be necessary before resistance data can be reliably compared. Further validation studies are proposed to ensure that the model is robust and applicable across a diverse range of farm types. The model will be used to demonstrate the advantage, in terms of delaying resistance development, of current guidelines for anthelmintic use and management practices for worm control in sheep.

The detection of anthelmintic resistance in nematodes of veterinary importance

Before revised World Association for the Advancement of Veterinary Parasitology (WAAVP) guidelines on the detection of anthelmintic resistance can be produced, validation of modified and new methods is required in laboratories in different parts of the world. There is a great need for improved methods of detection of anthelmintic resistance particularly for the detection of macrocyclic lactone resistance and for the detection of resistant nematodes in cattle. Therefore, revised and new methods are provided here for the detection of anthelmintic resistance in nematodes of ruminants, horses and pigs as a basis for discussion and with the purpose that they are evaluated internationally to establish whether they could in the future be recommended by the WAAVP. The interpretation of the faecal egg count reduction test has been modified and suggestions given on its use with persistent anthelmintics and continuous release devices. An egg hatch test for benzimidazole (BZ) resistance is described. A microagar larval development test for the detection of benzimidazole and levamisole resistance provides third stage larvae for the identification of resistant worms. The sensitivity of these two tests can be increased by using discriminating doses rather than LD(50) values. Details are given of a PCR based test for the analysis of benzimidazole resistance in strongyles of sheep and goats, horses and cattle. Although promising for ruminant trichostrongyles, quantitative determination of gene frequency using real time PCR requires further development before PCR tests will be used in the field. Apart from faecal egg count reduction tests there are currently no satisfactory tests for macrocylic lactone resistance despite the great importance of this subject. Except for treatment and slaughter trials there are no validated tests for fasciolicide resistance or for the detection of resistance in cestodes.

Randomized, multi-center trial of two hypo-energetic diets in obese subjects: high- versus low-fat content

OBJECTIVE

To investigate whether a hypo-energetic low-fat diet is superior to a hypo-energetic high-fat diet for the treatment of obesity.

DESIGN

Open-label, 10-week dietary intervention comparing two hypo-energetic (-600 kcal/day) diets with a fat energy percent of 20-25 or 40-45.

SUBJECTS

Obese (BMI >or=30 kg/m(2)) adult subjects (n = 771), from eight European centers.

MEASUREMENTS

Body weight loss, dropout rates, proportion of subjects who lost more than 10% of initial body weight, blood lipid profile, insulin and glucose.

RESULTS

The dietary fat energy percent was 25% in the low-fat group and 40% in the high-fat group (mean difference: 16 (95% confidence interval (CI) 15-17)%). Average weight loss was 6.9 kg in the low-fat group and 6.6 kg in the high-fat group (mean difference: 0.3 (95% CI -0.2 to 0.8) kg). Dropout was 13.6% (n = 53) in the low-fat group and 18.3% (n = 70) in the high-fat group (P=0.001). Among completers, more subjects lost >10% in the low-fat group than in the high-fat group ((20.8%, n = 70) versus (14.7%, n = 46), P = 0.02). Fasting plasma total, low-density lipoprotein- and high-density lipoprotein-cholesterol decreased in both groups, but more so in the low-fat group than in the high-fat group. Fasting plasma insulin and glucose were lowered equally by both diets.

CONCLUSIONS

The low-fat diet produced similar mean weight loss as the high-fat diet, but resulted in more subjects losing >10% of initial body weight and fewer dropouts. Both diets produced favorable changes in fasting blood lipids, insulin and glucose.

Characterisation of lesional infiltrates of dendritic cells and T cell subtypes during primary infestation of sheep with Psoroptes ovis, the sheep scab mite

Earlier studies of cattle and sheep have demonstrated that Psoroptes ovis infestations provoke an intense immunoinflammatory response dominated by eosinophils accompanied by a substantial infiltrate of lymphocytes. However, the kinetics of the lymphocyte response and the subtypes involved have not been characterised. We employed two groups of sheep to investigate the early (1-21 days) and later (21-63 days) infiltration of lymphocyte subpopulations and dendritic cells in primary infestations of sheep with P. ovis. Immunohistochemistry indicated that by 4 days after infestation numbers of CD4+ and CD45RA+ cells in lesional skin had increased significantly (P<0.03 and P<0.005, respectively) and that a significant increase in gammadelta T cells and dendritic cells (CD1b+) had occurred by 8 days (P<0.02 and P<0.01, respectively). Numbers of lymphocyte and dendritic cells declined from 49 to 63 days after infestation. Our observations suggest that mite-derived products exert a profound influence on the early recruitment of lymphocytes that may significantly influence the genesis of the adaptive immune response.

Agrobacterium-mediated transformation of Solanum phureja

A population of transgenic plants was produced by the transformation of internodal explants of Solanum phureja, DB337/37 (the cultivar Mayan Gold) using an Agrobacterium tumefaciens LBA4404-based vector containing a phytoene synthase gene (crtB). The regeneration strategy utilised a two-step protocol, with a 12-day callus induction stage mediated by 1.07 microM alpha-napthaleneacetic acid (NAA), 7.10 microM zeatin riboside and 0.06 microM gibberellic acid (GA3), followed by a prolonged (up to 90 day) shoot induction stage on medium containing 0.11 microM NAA, 7.10 microM zeatin riboside and 0.06 microM GA3 supplemented with kanamycin at 50 mg l(-1) as the selection agent. Southern analysis of the transgenic population revealed that the transgene copy number varied between one and five in the lines tested. Northern blot analysis showed significant expression of the introduced crtB gene in some lines during tuber development. Cytological analysis of the material showed a high incidence of chromosome doubling in the transgenic population with over 80% of all lines tested having doubled their chromosome complement during the transformation process.

Early Innate and Longer-term Adaptive Cutaneous Immunoinflammatory Responses during Primary Infestation with the Sheep Scab Mite, Psoroptes ovis

Clinical observation has indicated that Psoroptes ovis mites provoke cutaneous inflammation within hours of experimental infestation, but the nature of this reaction has not been described. After infestation of naive sheep with ovigerous P. ovis mites, significant influxes of eosinophils (P<0.004) and neutrophils (P<0.001) were detected within 24 h. A significant (P<0.001) increase in mast cell numbers was observed by 96 h post-infestation. In addition, marked degenerative and proliferative epidermal lesions were evident 24 and 96 h, respectively, after infestation. The influence of the later, adaptive response on the cellular infiltrate at the advancing margin of the lesion and the original site of infestation was also monitored. Mast cell numbers were greatest at 21 days while recruitment of eosinophils and neutrophils was maximal 63 days after infestation. Lesional severity was particularly pronounced from 42 to 63 days after infestation, but significant resolution had occurred by 84 days. Pathological changes at the advancing margin of the lesion were more severe than at the initial site of infestation, and this was reflected by the numbers of mites present. These data suggest that P. ovis elicits an early innate cutaneous response that is subsequently augmented by the development of an adaptive immune response, the intensity of which corresponds to the local population density of mites.

Regular meal frequency creates more appropriate insulin sensitivity and lipid profiles compared with irregular meal frequency in healthy lean women

OBJECTIVE

To investigate the impact of irregular meal frequency on circulating lipids, insulin, glucose and uric acid concentrations which are known cardiovascular risk factors.

DESIGN

A randomised crossover dietary intervention study.

SETTING

Nottingham, UK--Healthy free-living women.

SUBJECTS

A total of nine lean healthy women aged 18-42 y recruited via advertisement.

INTERVENTION

A randomised crossover trial with two phases of 14 days each. In Phase 1, subjects consumed their normal diet on either 6 occasions per day (regular) or by following a variable meal frequency (3-9 meals/day, irregular). In Phase 2, subjects followed the alternative meal pattern to that followed in Phase 1, after a 2-week (wash-out) period. Subjects were asked to come to the laboratory after an overnight fast at the start and end of each phase. Blood samples were taken for measurement of circulating glucose, lipids, insulin and uric acid concentrations before and for 3 h after consumption of a high-carbohydrate test meal.

RESULTS

Fasting glucose and insulin values were not affected by meal frequency, but peak insulin and AUC of insulin responses to the test meal were higher after the irregular compared to the regular eating patterns (P < 0.01). The irregular meal frequency was associated with higher fasting total (P < 0.01) and LDL (P < 0.05) cholesterol.

CONCLUSION

The irregular meal frequency appears to produce a degree of insulin resistance and higher fasting lipid profiles, which may indicate a deleterious effect on these cardiovascular risk factors.

SPONSORSHIP

: The Ministry of Health and Medical Education, IR Iran.

Growth and pathogenicity of isolates of the fungus Metarhizium anisopliae against the parasitic mite, Psoroptes ovis: effects of temperature and formulation

Psoroptes mites (Acari: Psoroptidae) are important ectoparasites of mammals, and are of particular economic significance as the agents of mange in sheep. To be effective against mites, putative fungal biocontrol agents must be able to operate at the relatively high temperatures and humidities found at the sheep skin surface. To consider this, the growth rates of different isolates of the entomopathogenic fungus Metarhizium anisopliae (Metschnikoff) Sorokin (Deuteromycotina: Hyphomycetes) were compared and the pathogenicity of these isolates against Psoroptes derived from rabbits (Psoroptes ovis Hering, syn P cuniculi) were evaluated at temperatures between 28 degrees C and 40 degrees C, and when formulated in either Tween 80 or silicone oil. For this study four multi-conidia, arthropod-derived, isolates of M anisopliae were used: from the USA, France, Denmark and Brazil. One single-conidia culture derived from the US isolate was also included in the investigation. Fungal growth was higher at the lower temperatures and none of the isolates grew at 40 degrees C. The growth of the US and single-conidia isolate declined markedly with temperature. In contrast, the Danish, French and Brazilian isolates grew almost as well at 32 degrees C and 35 degrees C as at 28 degrees C and 30 degrees C. The French and Brazilian isolates showed some growth at 37.5 degrees C but the Danish and US isolates did not. The number of fatal infections which resulted from exposure of mites to the fungal isolates was also strongly influenced by temperature. At 30 degrees C all isolates gave between 70 and 90% infection. The number of infections declined with increasing temperature and no infections were seen at 40 degrees C. However, the French and Danish isolates of M anisopliae gave higher numbers of infections than the other isolates at elevated temperatures. When formulated in silicone oil, significantly higher levels of infection were obtained than when formulated in Tween 80, even at the relatively high temperature of 37.5 degrees C. It is suggested that high-temperature adapted isolates of M anisopliae formulated in silicone oil offer good candidates as control agents under the conditions found at the sheep skin surface.

Assessment of fecal output in patients receiving enteral tube feeding: validation of a novel chart

OBJECTIVE

To develop a practical, valid and reliable chart to assist in the accurate visual characterization of fecal output in patients receiving enteral tube feeding (ETF).

DESIGN

A chart incorporating verbal and pictorial descriptors of fecal output was developed. Validity and reliability were assessed by a questionnaire survey of health professionals and a clinical study of patients commencing ETF. Content validity was assessed from the results of the questionnaire, construct validity by contrasting groups analysis, concurrent validity by comparison of the chart with actual fecal weight and inter-rater reliability by independent characterization of the same fecal sample by two nurses.

SETTING

St George's Hospital, London, UK.

SUBJECTS

In all, 35 health professionals completed a questionnaire with respect to the chart. The chart was then used to monitor fecal output in 36 patients commencing ETF for a total of 171 patient-days, during which time nurses used the chart to characterize 269 fecal samples, of which 59 were subsequently weighed.

RESULTS

The results of the questionnaire suggested good content validity. The chart demonstrated statistically significant differences in fecal frequency, fecal consistency, fecal score and incidence of diarrhea for contrasting patient groups expected to have different fecal output (P < 0.05). The inter-rater reliability was almost perfect for fecal consistency (95% agreement, kappa = 0.91) and substantial for fecal weight (83%, kappa = 0.75). In all, 83% of fecal samples were assigned to the correct weight category (kappa = 0.75).

CONCLUSION

The chart has good content, construct and concurrent validity and inter-rater reliability, and is suitable for both research and clinical use.

SPONSORSHIP

This research was jointly supported by King's College London and Nestlé, UK.

Carotenogenesis during tuber development and storage in potato

Germplasm of Solanum tuberosum and Solanum phureja exhibit a wide (over 20-fold) variation in tuber carotenoid content. The levels of carotenoids during tuber development and storage were compared in a high carotenoid-accumulating S. phureja accession (DB375\1) with two S. tuberosum cultivars (Pentland Javelin and Desiree) that accumulate lower levels of tuber carotenoid. On a dry weight basis, total carotenoid levels were at a maximum early in tuber development. However, in the S. phureja accession, carotenoid levels remained at a high level throughout tuber development, whereas in the S. tuberosum accessions, carotenoid content decreased as dry weight increased. The carotenoid profiles of tissues during tuber development were analysed in greater detail by reverse phase HPLC. In S. phureja tubers at maturity the major carotenoids were zeaxanthin, antheraxanthin, and violaxanthin. Following 9 months storage at 4 degrees C the levels of zeaxanthin and antheraxanthin decreased, whereas the level of lutein increased; overall, however, there was only a small decrease in total carotenoid content. In order to explore the reasons for the wide variation in tuber carotenoid content, the expression patterns of the major genes encoding the enzymes of the carotenoid biosynthetic pathway were compared. Significant differences in the profiles were detected, suggesting that transcriptional control or mRNA stability gives rise to the large differences in tuber carotenoid content. In particular, there was an inverse trend between the level of zeaxanthin epoxidase transcript level and tuber carotenoid content in a range of potato germplasm, giving rise to an hypothesis for the regulation of carotenogenesis in potato tubers.

Decreased thermic effect of food after an irregular compared with a regular meal pattern in healthy lean women

OBJECTIVES

To investigate the impact of irregular meal frequency on body weight, energy intake, appetite and resting energy expenditure in healthy lean women.

DESIGN

Nine healthy lean women aged 18-42 y participated in a randomised crossover trial consisting of three phases over a total of 43 days. Subjects attended the laboratory at the start and end of phases 1 and 3. In Phase 1 (14 days), subjects were asked to consume similar things as normal, but either on 6 occasions per day (regular meal pattern) or follow a variable predetermined meal frequency (between 3 and 9 meals/day) with the same total number of meals over the week. In Phase 2 (14 days), subjects continued their normal diet as a wash-out period. In Phase 3 (14 days), subjects followed the alternative meal pattern to that followed in Phase 1. Subjects recorded their food intake for three predetermined days during the irregular period when they were eating 9, 3 and 6 meals/day. They also recorded their food intake on the corresponding days during the regular meal pattern period. Subjects fasted overnight prior to each laboratory visit, at which fasting resting metabolic rate (RMR) was measured by open-circuit indirect calorimetry. Postprandial metabolic rate was then measured for 3 h after the consumption of a milkshake test meal (50% CHO, 15% protein and 35% fat of energy content). Subjects rated appetite before and after the test meal.

RESULTS

There were no significant differences in body weight and 3-day mean energy intake between the regular and irregular meal pattern. In the irregular period, the mean energy intake on the day when 9 meals were eaten was significantly greater than when 6 or 3 meals were consumed (P=0.0001). There was no significant difference between the 3 days of the regular meal pattern. Subjective appetite measurement showed no significant differences before and after the test meal in all visits. Fasting RMR showed no significant differences over the experiment. The overall thermic effect of food (TEF) over the 3 h after the test meal was significantly lower after the irregular meal pattern (P=0.003).

CONCLUSION

Irregular meal frequency led to a lower postprandial energy expenditure compared with the regular meal frequency, while the mean energy intake was not significantly different between the two. The reduced TEF with the irregular meal frequency may lead to weight gain in the long term.