First report of the use of mucosal swabs of the palatine tonsillar crypt for detection of Mycoplasma bovis in naturally infected calves.

Aims: To compare detection by real-time PCR of DNA from Mycoplasma bovis on mucosal swabs taken from the palatine tonsillar crypt and the mainstem bronchi of clinically asymptomatic calves after slaughter. Methods: We compared the sensitivity of mucosal swabs taken from two sites: the palatine tonsillar crypt and the mainstem bronchi. Paired samples were taken post-mortem at slaughter from 55 clinically well calves from an infected herd and were tested by real-time PCR for the presence of M. bovis-specific DNA. Results: Mycoplasma bovis DNA was detected in 51 palatine tonsillar crypt swabs (92.7 (95% CI = 82.4-98.0)%) and seven mainstem bronchial swabs (12.7 (95% CI = 5.3-24.5)%). All seven calves with positive mainstem bronchial swabs also had positive palatine tonsillar crypt swabs. Conclusions: When compared to mucosal swabs of the mainstem bronchi, mucosal swabs of the palatine tonsillar crypt were seven times more sensitive for the post-mortem detection of M. bovis DNA. The viability of detected M. bovis was not assessed, because any cattle carrying viable or non-viable M. bovis DNA were determined to be a potential risk to eradication. Palatine tonsillar crypt mucosa may be a useful anatomical site for real-time PCR detection of M. bovis DNA in naturally infected calves. More work is needed to define the persistence and viability of M. bovis at this anatomical site. Clinical relevance: The results of this study helped form the basis of surveillance tools used in M. bovis control and eradication efforts. Familiarity with these results may help veterinarians better communicate with their clients about the science behind the eradication efforts.

The immunogenicity and tissue reactivity of Mycobacterium avium subsp paratuberculosis inactivated whole cell vaccine is dependent on the adjuvant used.

Johne's disease (JD) is a chronic enteritis caused by Mycobacterium avium subspecies paratuberculosis (MAP). Current commercial vaccines are effective in reducing the occurrence of clinical disease although vaccinated animals can still become infected and transmit MAP. Many vaccinated sheep develop severe injection site lesions. In this study a range of adjuvants (Montanide TM ISA 50V, ISA 50V2, ISA 61VG, ISA 70 M VG, ISA 71 VG, ISA 201 VG and Gel 01 PR) formulated with heat-killed MAP were tested to determine the incidence of injection site lesions and the types of immune profiles generated in sheep. All the novel formulations produced fewer injection site lesions than a commercial vaccine (Gudair®). The immune profiles of the sheep differed between treatment groups, with the strength of the antibody and cell mediated immune responses being dependant on the adjuvant used. One of the novel vaccines resulted in a reduced IFN-γ immune response when a second "booster" dose was administered. These findings have significance for JD vaccine development because it may be possible to uncouple protective immunity from excessive tissue reactivity, and apparently poorly immunogenic antigens may be re-examined to determine if an appropriate immune profile can be established using different adjuvants. It may also be possible to formulate vaccines that produce targeted immunological profiles suited to protection against other pathogens, i.e. those for which a bias towards cellular or humoral immunity would be advantageous based on understanding of pathogenesis.

Sheep and cattle exposed to Mycobacterium avium subspecies paratuberculosis exhibit altered total serum cholesterol profiles during the early stages of infection.

Pathogenic mycobacteria such as Mycobacterium tuberculosis are capable of utilising cholesterol as a primary carbon-based energy source in vitro but there has been little research examining the significance of cholesterol in vivo. Johne's disease is a chronic enteric disease of ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP). This study sought to evaluate the levels of total serum cholesterol in the host following exposure to MAP. Blood samples were collected from both sheep and cattle prior to experimental challenge with MAP and at monthly intervals post-challenge. Total serum cholesterol levels in sheep challenged with MAP were significantly elevated at 9 weeks post-inoculation (wpi) in comparison to controls. When stratified based on disease outcome, there was no significant difference in serum cholesterol at the timepoints examined between MAP exposed sheep that were susceptible and those that were resistant to Johne's disease. There was a similar elevation in serum cholesterol at 9 wpi in cattle with histopathological gut lesions associated with disease or those with an early high IFN-γ response. Total serum cholesterol in exposed cattle was significantly lower when compared to controls at 13 wpi. Taken together, these results demonstrate changes in serum cholesterol following MAP exposure and disease progression which could reflect novel aspects of the pathogenesis and immune response associated with MAP infection in both sheep and cattle.

Case definition terminology for paratuberculosis (Johne's disease).

Paratuberculosis (Johne's disease) is an economically significant condition caused by Mycobacterium avium subsp. paratuberculosis. However, difficulties in diagnosis and classification of individual animals with the condition have hampered research and impeded efforts to halt its progressive spread in the global livestock industry. Descriptive terms applied to individual animals and herds such as exposed, infected, diseased, clinical, sub-clinical, infectious and resistant need to be defined so that they can be incorporated consistently into well-understood and reproducible case definitions. These allow for consistent classification of individuals in a population for the purposes of analysis based on accurate counts. The outputs might include the incidence of cases, frequency distributions of the number of cases by age class or more sophisticated analyses involving statistical comparisons of immune responses in vaccine development studies, or gene frequencies or expression data from cases and controls in genomic investigations. It is necessary to have agreed definitions in order to be able to make valid comparisons and meta-analyses of experiments conducted over time by a given researcher, in different laboratories, by different researchers, and in different countries. In this paper, terms are applied systematically in an hierarchical flow chart to enable classification of individual animals. We propose descriptive terms for different stages in the pathogenesis of paratuberculosis to enable their use in different types of studies and to enable an independent assessment of the extent to which accepted definitions for stages of disease have been applied consistently in any given study. This will assist in the general interpretation of data between studies, and will facilitate future meta-analyses.

Variation in susceptibility of different breeds of sheep to Mycobacterium avium subspecies paratuberculosis following experimental inoculation.

Exposure to Mycobacterium avium subspecies paratuberculosis (MAP) does not always lead to Johne's disease. Understanding differences in disease susceptibility of individual animals is a key aspect to controlling mycobacterial diseases. This study was designed to examine the susceptibility or resistance of various breeds of sheep to MAP infection. Merino, Suffolk first cross Merino, Border Leicester, and Poll Dorset sheep were orally inoculated with MAP and monitored for 14 months. Clinical disease occurred more frequently in the Merino (42%) and Suffolk first cross Merino (36%) compared to the Border Leicester (12%) and Poll Dorset (11%) breeds. Infection risk, as determined by culture of gut and associated lymphoid tissues, ranged from 75% for the Suffolk first cross Merino to 47% for the Poll Dorset sheep. Significant differences were identified in the site in the intestines of the most severe histopathological lesions and the immune responses to infection between the breeds. However, there was no difference in faecal MAP shedding by clinical cases between breeds. All breeds tested were susceptible to MAP infection, as determined by infection and clinical disease development, although there were differences in the proportions of diseased animals between the breeds. Poll Dorset and Border Leicester sheep were more resilient to MAP infection but there was evidence that more animals could have developed disease if given more time. These findings provide evidence of potential differential disease susceptibility between breeds, further our understanding of disease pathogenesis and risks of disease spread, and may have an influence on control programs for paratuberculosis.

Specific faecal antibody responses in sheep infected with Mycobacterium avium subspecies paratuberculosis.

Many studies have examined the serum antibody response to Mycobacterium avium subspecies paratuberculosis (MAP) infection in cases of Johne's disease (JD), but there are no reports on the mucosal antibody response. Faecal immunoglobulin (Ig) G and IgA ELISA responses were examined from sheep experimentally inoculated with MAP for up to 23 months post inoculation (PI). Corresponding serum IgG responses and the presence of viable MAP shed in faeces were also examined. The sheep were divided into three groups: (i) "un-inoculated controls" (n=10), (ii) "clinical cases" (n=8) which were inoculated animals that developed clinical disease and had moderate to high levels of MAP shedding and (iii) "survivors" (n=11) which were inoculated animals from which MAP could not be cultured from tissues at the conclusion of the trial. Serum IgG responses gradually increased in all inoculated animals, peaking at 12-16 months PI. A significant increase in the levels of MAP-specific faecal IgG and IgA was measured in the survivors at 16 and 17 months PI, while levels in the un-inoculated controls and clinical cases remained at baseline levels. The detection of faecal Ig in the survivors coincided with the removal of sheep that developed clinical disease. The data suggest that some sheep produced MAP-specific IgG and IgA in the intestinal mucosa, which was released into their faeces. We hypothesise that the survivors produced faecal Ig as a direct response to ingestion of MAP associated with environmental contamination from clinical cases. Thus MAP specific mucosal antibodies may play a previously unreported role as part of a protective response triggered by environmental exposure.

Histopathological Characterization of Cutaneous Delayed-type Hypersensitivity and Correlations with Intestinal Pathology and Systemic Immune Responses in Sheep with Paratuberculosis.

Cell-mediated immunity has been exploited historically in the diagnosis of mycobacterial diseases through elicitation of a delayed-type hypersensitivity (DTH) reaction following intradermal injection of an antigen. Here we describe the histopathological features of the cutaneous DTH reaction and its association with intestinal pathology and systemic immune responses in sheep with Mycobacterium avium subspecies paratuberculosis (MAP) infection. A mixed mononuclear cellular infiltrate dominated the DTH reaction and was present in perivascular and periadnexal patterns. Multiple multinucleate giant cells were present in the cellular infiltrate in one sheep while plasma cells were an obvious feature in six others. Sheep with paucibacillary intestinal lesions had the greatest degrees of cutaneous induration, more severe cellular infiltration in DTH lesions and high systemic interferon (IFN)-γ production. In contrast, sheep with multibacillary intestinal lesions, and particularly those with dissemination of MAP to extra-intestinal tissues, had minimal cutaneous induration, nil to mild cellular infiltration in DTH lesions and high serum anti-MAP antibody levels. Systemic IFN-γ production generally was augmented following skin sensitization. In general, the gross and histopathological features of the cutaneous DTH response matched the stage of paratuberculosis reflected by intestinal pathology and systemic measures of humoral and cellular immunity.

Development of 316v antibody enzyme-linked immunosorbent assay for detection of paratuberculosis in sheep.

An enzyme-linked immunosorbent assay (ELISA) was developed and optimised using a Mycobacterium avium subspecies paratuberculosis (MAP) antigen prepared from a C strain (316v) passed through a French press. The optimised assay was evaluated with a panel of sera from MAP infected (n = 66) and uninfected (n = 1,092) sheep. Animals in the MAP infected category were positive on either tissue culture or histopathology but were of unknown serum antibody status. The diagnostic performance and cost of the assay were compared with those of a commercial ELISA (IDEXX). At 99.8% diagnostic specificity the assay showed a diagnostic sensitivity of 23% (95% CI: 15.1-35.8) compared with 36.4% (95% CI: 25.8-48.4) for the commercial ELISA (McNemar's test: chi-square 5.82, p < 0.05). The sensitivities were 5.9% (95% CI: 1-26.9), 27.9% (95% CI: 14.7-45.7) and 35% (95% CI: 18.1-56.7), for low grade, paucibacillary and multibacillary lesion grades, respectively. The cost of the commercial assay kit was 2.7 to 5.2 times greater than that of the 316v ELISA for an equivalent number of tests, the multiple depending on the number of plates processed per run. For flock-level surveillance, to account for the lower sensitivity of the 316v ELISA compared with the commercial ELISA, sample sizes would be increased but the test cost would still be lower. The 316v assay will be useful for diagnosis of Johne's disease in sheep flocks, particularly in developing countries where labour costs are low relative to the cost of consumables.

Improvements in hippocampal-dependent memory and microglial infiltration with calorie restriction and gastric bypass surgery, but not with vertical sleeve gastrectomy.

BACKGROUND: Much recent evidence suggest that obesity and related comorbidities contribute to cognitive decline, including the development of non age-related dementia and Alzheimer's disease. Obesity is a serious threat to public health, and few treatments offer proven long-term weight loss. In fact, bariatric surgery remains the most effective long-term therapy to reduce weight and alleviate other aspects of the metabolic syndrome (MetS). Unlike the demonstrated benefits of caloric restriction to prevent weight gain, few if any studies have compared various means of weight loss on central nervous system function and hippocampal-dependent cognitive processes. DESIGN AND RESULTS: Our studies comprise the first direct comparisons of caloric restriction to two bariatric surgeries (Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG)) on cognitive function. Weight loss following caloric restriction, RYGB and VSG was associated with generalized improvements in metabolic health and hippocampal-dependent learning, as measured in the radial arm maze and spontaneous alternation tests. However, VSG-treated rats exhibited deficits on spatial learning tasks in the Morris water maze. In addition, whereas VSG animals had elevated hippocampal inflammation, comparable to that of obese controls, RYGB and calorie-restricted (pair-fed, PF) controls exhibited an amelioration of inflammation, as measured by the microglial protein ionized calcium binding adaptor molecule 1 (IBA1). We also assessed whether GHR (ghrelin) replacement would attenuate hippocampal inflammation in VSG, as post-surgical GHR levels are significantly reduced in VSG relative to RYGB and PF rats. However, GHR treatment did not attenuate the hippocampal inflammation. CONCLUSION: Although VSG was comparably effective at reducing body weight and improving glucose regulation as RYGB, VSG did not appear to confer an equal benefit on cognitive function and markers of inflammation.

Learner driver experiences and crash risk as an unsupervised driver.

OBJECTIVE: The purpose of this study was to describe the driving experiences of learner licensed drivers and examine the association between these driving experiences, associated factors, and on-road car crash involvement during the unsupervised restricted license stage. METHODS: Data were drawn from a cohort investigation of newly licensed drivers. Information on demographic characteristics, personality, and risk behaviors was collected at the baseline interview. At the first follow-up interview (restricted license stage) study members were asked details about their experiences as a learner licensed driver: professional driving lessons, supervised driving, unsupervised driving, and driving courses in which they participated. During the second follow-up interview (full license stage), data were collected on crash involvement and driving exposure during the restricted license stage. Regression analysis was used to determine independent relationships between learner license driving experience variables and crash involvement. RESULTS: After adjusting for demographic, personality factors, and driving exposure at the restricted license stage, increased time spent on the learner license was associated with a reduced risk of crash involvement during the unsupervised restricted license stage. CONCLUSION: Results presented in this paper suggest that learner drivers in New Zealand should be encouraged to spend more time on their learner license to enable them to gain skills and experience to help reduce their crash risk when they are allowed to drive unsupervised. IMPACT ON INDUSTRY: Compared with novice drivers who are on their learner license for the least amount of time, those who spend the most amount of time on their learner license have reduced risk of on-road crash involvement as an unsupervised driver. Learner drivers and their supervisors need to be aware of the length of time required for practice in order to reduce the risks of crash involvement when they are able to drive unsupervised (O'Brien et al., 2012). The recently introduced increase in the minimum driver licensing age in NZ, tougher restricted license stage driving test (aimed at encouraging 120 hours of supervised driving), and the Safe Teen driver campaign (NZ Transport Agency, 2012) are all strategies targeted at improving the safety of learner drivers. These strategies need to be evaluated to ensure they are achieving their goals.

Angiotensin-converting enzyme inhibition reverses diet-induced obesity, insulin resistance and inflammation in C57BL/6J mice.

AIM: Angiotensin-converting enzyme (ACE) inhibition can reduce the body weight of mice maintained on a high-fat diet. The current study examined the effect of the ACE inhibitor, captopril (CAP), on the reversal of diet-induced obesity (DIO), insulin resistance and inflammation in mice. MATERIALS AND METHODS: DIO was produced in C57BL/6J male mice (n=30) by maintaining animals on a high-fat diet (w/w 21% fat) for 12 weeks. During the subsequent 12-week treatment period, the animals were allowed access to the high-fat diet and either water containing CAP (0.05 mg ml(-1)) or plain tap water (CON, control). RESULTS: From the first week of treatment, food intake and body weight decreased in CAP-treated mice compared with CON mice. Both peripheral insulin sensitivity and hepatic insulin sensitivity were improved in CAP-treated mice compared with CON mice. CAP-treated mice had decreased absolute and relative liver and epididymal fat weights compared with CON mice. CAP-treated mice had higher plasma adiponectin and lower plasma leptin levels than CON mice. Relative to CON mice, CAP-treated mice had reduced adipose and skeletal muscle monocyte chemoattractant protein 1 (MCP-1), adipose interleukin-6 (IL-6), toll-like receptor 4 (TLR4) and uncoupling protein 2 (UCP2) mRNA expressions. Furthermore, CAP-treated mice had increased peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), long chain acyl-CoA dehydrogenase (LCAD), hormone sensitive lipase (HSL) and decreased lipoprotein lipase (LPL) mRNA expressions in the liver. CONCLUSION: The results of the current study indicate that in mice with DIO, CAP treatment reduced food intake and body weight, improved insulin sensitivity and decreased the mRNA expression of markers of inflammation. Thus, CAP may be a viable treatment for obesity, insulin resistance and inflammation.

Biomarker discovery for ovine paratuberculosis (Johne's disease) by proteomic serum profiling.

Paratuberculosis (Johne's disease) is a chronic granulomatous enteritis affecting ruminants and other species. It is caused by Mycobacterium avium subsp. paratuberculosis (MAP). In this study, surface enhanced laser desorption ionization time-of-flight mass spectrometry (SELDI TOF-MS) was used as a platform to identify candidate biomarkers from sheep serum. Multivariate biomarker models which aimed to differentiate sheep with paratuberculosis and vaccinated-exposed sheep from unexposed animals were proposed based on classification and regression tree (CART) and linear discriminant analysis (LDA) algorithms from two array types. The accuracy of classification of sheep into unexposed or exposed groups ranged from 75 to 100% among models. SELDI was used to monitor protein profile changes over time during an experimental infection trial by examining sera collected at 4-, 8- and 13-months post infection. Although three different SELDI instruments were used, nine consistent proteomic features were observed associated with exposure to MAP. Two of the putative serum biomarkers were purified from serum using chromatographic methods and were identified as transthyretin and alpha haemoglobin by tandem mass spectrometry. They belong to highly abundant, acute phase reactants in the serum proteome and have also been discovered as serum biomarkers in human inflammatory conditions and cancer. Their relationship to the pathogenesis of Johne's disease remains to be elucidated.

Does a Th1 over Th2 dominancy really exist in the early stages of Mycobacterium avium subspecies paratuberculosis infections?

The immune response of ruminants to Johne's disease has been long associated with a cell mediated immune (CMI) response in the early stages of infection with a switch to an antibody response later as the disease manifests. This study examines the immune response in sheep to Mycobacterium avium subspecies paratuberculosis (Map) infections, specifically the antigen-specific interferon gamma (IFN-γ) and antibody responses as surrogates of T helper-1 (Th1) and Th2 immunity. The difference in IFN-γ production between paucibacillary and multibacillary diseased animals was also examined. The results show that sheep are more likely to have a combined antibody and IFN-γ response (seen in 50% of the animals) rather than a switch from an IFN-γ to antibody response (39%). Multibacillary diseased animals were found to have a decrease in functional ability to produce IFN-γ from cells stimulated with MAP-specific antigens and non-specific mitogens. This indicates that the immune responses to Map infections are more complex than thought, where both antibody and cellular immunity may play key roles in the early stages of disease manifestation or resistance. The loss of the cellular response in multibacillary animals may be an indication that the entire immune response is dysfunctional, with the cell mediated responses becoming affected first.

Sodium appetite in adult rats following ω-3 polyunsaturated fatty acid deficiency in early development.

We examined the effect of ω-3 polyunsaturated fatty acid (PUFA) deficiency during development on sodium appetite. Being raised on an ω-3 PUFA deficient diet increased the intake of 0.5M NaCl following furosemide-induced sodium depletion by 40%. This occurred regardless of the diet they were maintained on later in life, and the increased consumption persisted for 3 days. In a second study, animals were administered furosemide and low-dose captopril. Sodium consumption of deficient raised animals was again higher than that of the control raised. Fos immunoreactivity in brain areas associated with sodium appetite and excretion were not influenced by diet. Our findings indicate that inadequate dietary ω-3 PUFA during development results in an exaggerated sodium appetite later in life.

New Zealand Drivers Study: a follow-up study of newly licensed drivers.

BACKGROUND: Despite significant improvement since graduated licensing was introduced, traffic-related injury remains the leading cause of death and hospitalisation among young New Zealanders. Most research to date has used routinely collected crash data but has been limited in that these databases do not, and realistically cannot, include the level of detail required to ensure that learner driver policy and programmes are based on sound scientific evidence applicable to young drivers in the current New Zealand context. OBJECTIVES: To examine the driving-related experiences of newly licensed drivers to identify factors associated with increased or decreased risk of negative traffic outcomes. DESIGN: Multistage prospective cohort study. SETTING: New Zealand. PARTICIPANTS: Newly licensed drivers. EXPOSURES: background demographic details, pre-licence driving, previous crashes, driving intentions, motivations for driving and licensing, sensation seeking, aggression, impulsivity, quality and quantity of driving experience, driving supervision, driving behaviour, alcohol and other drug use, compliance with New Zealand's graduated driver licensing scheme, driver training/education, cell phone use, and sleep. OUTCOMES: crash, conviction, infringements, risky driving. EXPOSURES: participants and their parents. Outcomes: participants and official records. BIAS: On the basis of a pilot study, participation and attrition bias are likely to be minimal. A comparison of baseline data for those followed and those not followed will be undertaken. Information bias will be minimised by standardised questionnaires. Information on potential confounders is to be collected and controlled for in analyses. STUDY SIZE: 5000 (including 1500 Maori). STATISTICAL METHODS: Survival analysis, logistic or Poisson regression, generalised estimating equations.

Identification of differentially expressed genes in ileum, intestinal lymph node and peripheral blood mononuclear cells of sheep infected with Mycobacterium avium subsp. paratuberculosis using differential display polymerase chain reaction.

Discovery of differentially expressed genes aids in understanding molecular mechanisms underpinning normal and pathological states. When studying animals such as sheep where the entire genome has not been characterized, techniques that do not require knowledge of gene sequences are particularly advantageous. We used one such technique, differential display polymerase chain reaction (DD-PCR), to identify genes that had different degrees of expression in response to Mycobacterium avium subsp. paratuberculosis (M. ptb), the organism that causes Johne's disease in ruminants. Differentially expressed genes were validated by quantitative PCR using especially selected reference genes established in this study. Sheep (n=47) were classified according to history of exposure to M. ptb and infection status by histology and faecal and tissue culture. Differences in levels of gene expression were analyzed using restricted maximum likelihood (REML) in a linear mixed model. Five genes from the ileum and 17 genes from lymph node were differentially expressed in ovine Johne's disease. Expression of seven of these genes was also significantly different in peripheral blood mononuclear cells. Genes identified in association with M. ptb infection had a wide range of functions in pathways including: antigen presentation, signal transduction and cell differentiation, TLR signaling, immune cell activation and chemokine functions, granulomatous inflammation, Th1 suppression and apoptosis.

Endocrine and ingestive behavioral responses to fluid deprivation in sheep chronically exposed to ethanol.

Endocrine responses to fluid deprivation/restoration and preference for ethanol solution vs. water were assessed in sheep maintained for 5 months on a 10% ethanol solution as their sole source of fluid. Blood pressure, body weight, plasma composition and hormone levels of the alcohol maintained sheep were all within a normal range, except for high plasma concentrations of ANG II and ALDO. During fluid deprivation, AVP concentration increased and fluid-deprived sheep displayed a natriuresis and then a rehydration anti-natriuresis. Sheep did not drink the 10% ethanol solution avidly upon fluid restoration, preferring to drink steadily over the following 24 h; there was an associated increase in blood alcohol concentration (BAC). PRC, ANG II and ALDO all increased throughout the fluid restoration period, whereas plasma AVP and ANP gradually fell. In a separate experiment when water was also supplied to the sheep, they preferred water to 10% ethanol; however, alcohol intake was not eliminated. Overall, this degree of chronic consumption of 10% ethanol solution did not appear to adversely affect physiological mechanisms concerned with body fluid homeostasis after fluid deprivation conditions.

Omega-3 polyunsaturated fatty acid supplementation reduces hypertension in TGR(mRen-2)27 rats.

To establish the effect of dietary omega-3 PUFA on angiotensin II (ANG II)-mediated hypertension, male TGR (mRen-2)27 (Ren-2) rats (animals with high ANG II activity) were maintained on a diet either deficient or sufficient in omega-3 PUFA from conception. Half the animals on each diet were treated with the angiotensin-converting enzyme inhibitor, perindopril, from birth. Ren-2 rats fed the omega-3 PUFA deficient diet were significantly more hypertensive than those fed the omega-3 PUFA sufficient diet. Perindopril reduced the blood pressure of both omega-3 PUFA-deficient and omega-3 PUFA-sufficient diet-fed Ren-2 rats. Body weight, body fat and plasma leptin were reduced by perindopril treatment but not affected by omega-3 PUFA supply. Given that the elevated blood pressure of the Ren-2 rat is mediated by ANG II, the data suggest that omega-3 PUFA may reduce hypertension via the renin-angiotensin system.

The role of adrenal or testicular hormones in voluntary ethanol and NaCl intake of crowded and individually housed rats.

The effect of adrenalectomy or castration on the ingestive behaviour of 10% ethanol, 0.5 M NaCl, water, and food was investigated in 2 models of increased/high ethanol consumption (1) adult male rats, previously individually housed with low ethanol intake, moved crowded housing and (2) individually housed adult male rats with high ethanol intake in the absence of any known aetiology. In study 1, rats that had been previously individually housed were paired with an animal in a small cage with ad libitum access to 10% ethanol intake, 0.5 M NaCl, water, and food at all times. Rats significantly increased 10% ethanol intake after they were pair-housed. The pairs were either adrenalectomized, castrated or sham operated. Neither adrenalectomy nor castration resulted in a significant change in 10% ethanol intake. 0.5 M NaCl intake was elevated and food intake and body weight were decreased in adrenalectomized rats. In study 2, rats that consumed large amounts of ethanol in the absence of any known aetiology remained in individual housing. Ethanol intake was decreased subsequent to either adrenalectomy or castration; adrenalectomy resulted in an increase in 0.5 M NaCl intake. These results suggest that the influence of adrenal or testicular hormones on ethanol intake is situation dependent. The increase in ethanol intake induced by placing animals in crowded housing appears to be independent of these hormones.

Failure of conjugated linoleic acid supplementation to enhance biosynthesis of docosahexaenoic acid from alpha-linolenic acid in healthy human volunteers.

A rate-limiting step in docosahexaenoic acid (DHA) formation from alpha-linolenic acid (ALA) involves peroxisomal oxidation of 24:6n-3 to DHA. The aim of the study was to determine whether conjugated linoleic acid (CLA) would enhance conversion of ALA to DHA in humans on an ALA-supplemented diet. The subjects (n=8 per group) received daily supplementation of ALA (11g) and either CLA (3.2g) or placebo for 8 weeks. At baseline, 4 and 8 weeks, blood was collected for plasma fatty acid analysis and a number of physiological measures were examined. The ALA-supplemented diet increased plasma levels of ALA and eicosapentaenoic acid (EPA). The addition of CLA to the ALA diet resulted in increased plasma levels of CLA, as well as ALA and EPA. Plasma level of DHA was not increased with either the ALA alone or ALA plus CLA supplementation. The results demonstrated that CLA was not effective in enhancing DHA levels in plasma in healthy volunteers.