Non-invasive electrocardiographic assessments of cardiac autonomic modulation in individuals with spinal cord injury.

STUDY DESIGN: Review. OBJECTIVES: The purpose of this review is to discuss the utility of linear and non-linear heart rate variability (HRV) as well as the QT-variability index (QTVI) as indices of cardiac autonomic control in individuals with spinal cord injury (SCI). SETTING: Brock University, Department of Kinesiology, St Catharines, Ontario, Canada. Brock-Niagara Centre for Health and Well-being, St Catharines, Ontario, Canada. METHODS: Literature review. CONCLUSION: Non-invasive markers determined from the electrocardiogram, such as linear and non-linear HRV, and, more recently, the QTVI have all shown some promise as indices of cardiac autonomic regulation in the SCI population. However, there are inconsistencies in the literature that call to question their true validity in this regard. Studies using pharmacological blockade, sympathetic manoeuvres and exercise suggest that both linear and non-linear HRV reflect cardiac parasympathetic activity, whereas their ability to quantify cardiac sympathetic outflow remains uncertain. The QTVI, although a novel method, correlates with both limbs of the autonomic nervous system and therefore may hold value as a measure of both cardiac sympathetic and parasympathetic activity in individuals with SCI; however, more research is required to confirm its utility.

Isometric handgrip training lowers blood pressure and increases heart rate complexity in medicated hypertensive patients.

Hypertension is characterized by elevated blood pressure (BP) and autonomic dysfunction, both thought to be improved with exercise training. Isometric handgrip (IHG) training may represent a beneficial, time-effective exercise therapy. We investigated the effects of IHG training on BP and traditional and nonlinear measures of heart rate variability (HRV). Pre- and post-measurements of BP and HRV were determined in 23 medicated hypertensive participants (mean ± SEM, 66 ± 2 years) following either 8 weeks of IHG training (n = 13) or control (n = 10). IHG exercise consisted of four unilateral 2-min isometric contractions at 30% of maximal voluntary contraction, each separated by 4 min of rest. IHG training was performed 3 days/week for 8 weeks. IHG training decreased systolic BP (125 ± 3 mmHg to 120 ± 2 mmHg, P < 0.05) and mean BP (90 ± 2 mmHg to 87 ± 2 mmHg, P < 0.05), while sample entropy was increased (1.07 ± 0.1 to 1.35 ± 0.1, P < 0.05) and the fractal scaling distance score was decreased (0.34 ± 0.1 to 0.19 ± 0.1, P < 0.05). No significant changes were observed in traditional spectral or time-domain measures of HRV or control participants. IHG training improves nonlinear HRV, but not traditional HRV, while reducing systolic and mean BP. These results may highlight the benefits of IHG training for patients with primary hypertension.

Autonomic recovery following sprint interval exercise.

The autonomic nervous activity was assessed following supramaximal exercise through heart rate (HR) and blood pressure (BP) variability (HRV and BPV) and baroreflex sensitivity (BRS). The beat-to-beat HR and BP were recorded during the supine and standing states before (PRE) and at 60 (R60) and 120 min (R120) following single (one Wingate, 1W) and multiple sprint intervals (four Wingates interspersed with 4 min of light cycling, 4W). The supine low frequency (LF) component was increased (P<0.001) and the high frequency (HF) was reduced (P<0.01) at R60 (LF, 178.1 ± 11.0; HF, 74.8 ± 10.5) compared with PRE (LF, 140.2 ± 7.4; HF, 110.4 ± 7.2) after both exercises. Supine systolic BPV LF:HF was higher at R60 (4.6 ± 1.4) compared with PRE (6.8 ± 2.4) only after 4W (P=0.035). Supine BRS was lower (P<0.001) at R60 (6.8 ± 1.1) than at PRE (15.3 ± 1.8) and R120 (11.3 ± 1.3). BRS at R120 remained lower after 4W (P=0.02). Standing BRS was less (P<0.001) at R60 (2.3 ± 0.5) than at PRE (5.6 ± 0.8) or R120 (3.7 ± 0.6) and returned to PRE values only after 1W. We concluded that (a) autonomic balance is shifted to a greater sympathetic and less parasympathetic activation following both types of exercise, (b) it takes longer than 1 h to recover following supramaximal exercise and (c) the recovery is longer after 4W than 1W.

Effects of isometric handgrip protocol on blood pressure and neurocardiac modulation.

Isometric handgrip (IHG) remains a well-studied cardiovascular and autonomic stimulus, however the effects of rhythmic IHG protocols remain largely unknown. The purpose of this study was to investigate the acute effects of 4 IHG protocols on blood pressure (BP) and neurocardiac reactivity and recovery responses. 12 healthy older participants (70±5 yrs, ♀=4) each completed 4 bilateral 12-min protocols (sham, IHG1, IHG2, IHG3) on separate visits. IHG1, IHG2, and IHG3 consisted of 4×2-min, 8×1-min, and 16×30-s isometric contractions, respectively, each completed at 30% MVC, while sham consisted of 4×2-min contractions completed at 3% MVC. BP and neurocardiac modulation were assessed during and following each protocol. Systolic BP (SBP) reactivity was increased during IHG1 compared to IHG2 (p<0.05), IHG3 (p<0.05), and sham (p<0.01), although during recovery delta SBP was lower following IHG1 (p<0.01), IHG2 (p<0.01), and IHG3 (p<0.05), compared to sham. Sample entropy, a measure of nonlinear heart rate variability was reduced during IHG1 (p<0.01) and IHG2 (p<0.05), while increased following IHG1 (p<0.05) and IHG3 (p<0.05), compared to sham. In conclusion, recovery responses from rhythmic IHG appear independent of contraction and/or rest period frequency-duration relationships. Investigation of rhythmic IHG protocols warrants further examination.

PREVALENCE AND MOLECULAR CHARACTERIZATION OF DIROFILARIA IMMITIS (FILARIOIDEA: ONCHOCERCIDAE) IN DOGS FROM ENDEMIC AREAS OF RIO DE JANEIRO STATE, BRAZIL.

Canine dirofilariasis is common in Brazil, but molecular diagnosis is rare even though molecular studies increase our knowledge about molecular epidemiology and circulating genotypes from helminths worldwide. This study aims to estimate the prevalence of infection with a modified Knott's test and to perform molecular characterization of Dirofilaria immitis (Leidy, 1856) Railliet and Henry, 1911, in dogs from endemic areas of Maricá and Niterói municipalities, Rio de Janeiro State, Brazil. Molecular characterization was performed in 33 blood samples from dogs positive for microfilariae and 4 adult worms obtained from 2 other dogs. DNA extraction followed by PCR for mitochondrial target 12S rDNA and cytochrome oxidase subunit 1 (COI) of D. immitis were performed, and the amplified products were sequenced. All sequences were identical for both gene targets and showed 100% identity with D. immitis sequences from different animal species from various countries. The study concluded that this genotype of D. immitis might be dispersed worldwide.

Skill shortages in health: innovative solutions using vocational education and training.

INTRODUCTION: This article reports findings of a project funded by the Australian National Council for Vocational Education Research. The project explores solutions to current and projected skills shortages within the health and community services sector, from a vocational education and training perspective. Its purpose is to locate, analyse and disseminate information about innovative models of health training and service delivery that have been developed in response to skill shortages. METHODS: The article begins with a brief overview of Australian statistics and literature on the structure of the national health workforce and perceived skill shortages. The impact of location (state and rurality), demographics of the workforce, and other relevant factors, on health skill shortages is examined. Drawing on a synthesis of the Australian and international literature on innovative and effective models for addressing health skill shortages and nominations by key stakeholders within the health sector, over 70 models were identified. The models represent a mixture of innovative service delivery models and training solutions from Australia, as well as international examples that could be transposed to the Australian context. They include the skill ecosystem approach facilitated by the Australian National Training Authority Skill Ecosystem Project. Models were selected to represent diversity in terms of the nature of skill shortage addressed, barriers overcome in development of the model, healthcare specialisations, and different customer groups. RESULTS: Key barriers to the development of innovative solutions to skills shortages identified were: policy that is not sufficiently flexible to accommodate changing workplace needs; unwillingness to risk take in order to develop new models; delays in gaining endorsement/accreditation; current vocational education and training (VET) monitoring and reporting systems; issues related to working in partnership, including different cultures, ways of operating, priorities and timelines; workplace culture that is resistant to change; and organisational boundaries. For training-only models, additional barriers were: technology; low educational levels of trainees; lack of health professionals to provide training and/or supervision; and cost of training. Key enhancers for the development of models were identified as: commitment by all partners and co-location of partners; or effective communication channels. Key enhancers for model effectiveness were: first considering work tasks, competencies and job (re)design; high profile of the model within the community; community-based models; cultural fit; and evidence of direct link between skills development and employment, for example VET trained aged care workers upskilling for other health jobs. For training only models, additional enhancers were flexibility of partners in accommodating needs of trainees; low training costs; experienced clinical supervisors; and the provision of professional development to trainers. CONCLUSIONS: There needs to be a balance between short-term solutions to current skill shortages (training only), and medium to longer term solutions (job redesign, holistic approaches) that also address projected skills shortages. Models that focus on addressing skills shortages in aged care can provide a broad pathway to careers in health. Characteristics of models likely to be effective in addressing skill shortages are: responsibility for addressing skills shortage is shared between the health sector, education and training organisations and government, with employers taking a proactive role; the training component is complemented by a focus on retention of workers; models are either targeted at existing employees or identify a target group(s) who may not otherwise have considered a career in health.

Beneficial metabolic actions of a stable GIP agonist following pre-treatment with a SGLT2 inhibitor in high fat fed diabetic mice.

The purpose of the present study was to examine if a stable glucose-dependent insulinotropic polypeptide (GIP) agonist could exert beneficial metabolic control in diabetic mice which had been pre-treated with sodium-glucose-cotransporter-2 (SGLT2) inhibitor dapagliflozin (DAPA). High fat fed mice administered low dose streptozotocin (STZ) received vehicle, DAPA once-daily over 28 days, or DAPA once-daily for 14 days followed by (DAla(2))GIP once-daily for 14 days. Energy intake, body weight, glucose and insulin concentrations were measured at regular intervals. Glucose tolerance, insulin tolerance test, dual-energy X-ray absorptiometry (DEXA) and pancreatic histology were examined. Once-daily administration of (DAla(2))GIP for 14 days in high fat fed diabetic mice pre-treated with DAPA demonstrated significant decrease in body weight, blood glucose and increased insulin concentrations which were independent of changes in energy intake. Similarly, glucose tolerance, glucose-stimulated insulin secretion, insulin sensitivity and HOMA-ß were significantly enhanced in (DAla(2))GIP-treated mice. DEXA analysis revealed sustained percentage body fat loss with no changes in lean mass, bone mineral content and density. Pancreatic immunohistochemical analysis revealed decreased islet number and increases in islet area, beta cell area and pancreatic insulin content. The DAPA-induced increase in alpha cell area was also reversed. Additional acute in vitro and in vivo experiments confirmed that the impaired action of (DAla(2))GIP under hyperglycaemic-induced conditions was significantly reversed by DAPA treatment. These data demonstrate that (DAla(2))GIP can exert beneficial metabolic control in high fat fed diabetic mice pre-treated with DAPA. The results highlight possibility of a targeted and personalized approach using a GIP agonist and SGLT2 inhibitor for the treatment of type 2 diabetes.

Changes in serum immunoglobulin levels in Jerseys and Friesians near calving.

IgG1 and IgM levels were significantly lower in bovine serum from four weeks before, until at least two months after calving, whereas IgG2 levels were elevated at this time. The shapes of the changes in Ig levels were different for first and second calving and it appeared that IgG1 levels were secreted earlier, from serum to colostrum, in heifers. Changes in management caused marked changes in Ig levels particularly after third calving when the cows were transferred from a balanced complete diet to grass or hay. IgG1 levels increased by 130 per cent and stayed high whereas the increase in IgM was transitory, and IgG2 levels largely unaffected. In Friesians the IgG2 levels increased with age as anticipated from previous studies but in Jerseys the levels appeared to decline with age. Mean IgG2 levels in Jerseys were also significantly lower than in Friesians.

Changes in IgG2 levels with age in British cattle.

IgG1, IgG2 and IgM levels were measured in serum samples from 282 cattle of various ages and the results analysed by least squares. There were marked increases with age in IgG2 levels in bulls, and in dairy cattle in the absence of culling for disease or low production traits. There was about a 300% increase between one year and eight years of age for IgG2 compared with the small increase of about 20% for IgG1 but there was no apparent effect of age on IgM levels. There were no differences between Hereford and Friesian bulls for any of the immunoglobulins but there were environmental differences, between AI centres, for IgG1 and IgM. No animals were found to be immunodeficient but IgG2 levels ranged widely from 1 mg/ml to 35 mg/ml in different bulls.

The effects of progesterone and oestradiol-17beta treatment on plasma hormone levels and on the reproductive behaviour of ewes in late anoestrus and early in the breeding season.

PIP: The effects of progesterone and estradiol-17beta on plasma hormone levels and on reproductive behavior in ewes in late anestrus or the early breeding season were investigated. The ewes received sc implants of progesterone in conjunction with injections of estradiol-17beta. Removal of the implants in anestrous ewes was followed by a surge of plasma gonadotropins 20-48 hours later. The time from removal to the surge was significantly (p less than .001) shortened (7-20 hours) when estradiol was injected at the time of removal. 21 of 23 noncyclic ewes exhibited cyclical activity following treatment. 15 of these showed estrous behavior during the 4 days following removal of the implants. However, only 1 conception occurred in this group, while the conception rate was 82 percent among 17 ewes showing behavioral estrus at 15-21 days after implant removal. Removal of the implants from cyclic ewes had little effect on their estrous cycles, and no gonadotropin surge was observed. However, the injection of estradiol at the time of implant removal produced some degree of estrous synchronization in cycling animals.^ieng

In vitro infection of bovine alloreactive cytotoxic T cell lines with sporozoites of Theileria annulata and T parva.

Bovine alloreactive cytotoxic lymphocyte (CTL) lines of known target specificity were infected in vitro with sporozoites of Theileria annulata and T parva and cultured in limiting dilution. The phenotypes of the CTL lines both pre- and post infection were assessed using a panel of monoclonal antibodies specific for defined bovine lymphocyte subpopulations. The effector function of the resultant infected cell lines was determined using a Cr51 release assay and compared to the uninfected control CTL line. The results indicated that T parva sporozoites consistently infected and transformed the CTL lines very efficiently even at the lowest cell doses. In contrast the T annulata sporozoites were largely unable to infect and transform the alloreactive CTL except at the very highest cell and sporozoite doses. A factor which appeared to influence susceptibility to T annulata infection was an increased level of class II expression on the CTL line. None of the cell lines showed cytotoxic effector function after infection with either T annulata or T parva sporozoites.

Bovine auto-immune haemolytic anaemia.

A six-months-old heifer died within two days of showing signs of anaemia and dyspnoea. The death was attributed to autoimmune haemolytic anaemia (AHA) because of auto-agglutination which increased on Coomb's testing and the presence of antibovine IgG on the erythrocyte surfaces.

Sensitivity and specificity of serological tests, histopathology and immunohistochemistry for detection of Toxoplasma gondii infection in domestic chickens.

Since free-range chickens are important for the epidemiology of toxoplasmosis, this study evaluated the sensitivity and specificity of different laboratory techniques for the diagnosis of Toxoplasma gondii in these animals. Serum samples from 135 adult domestic chickens were tested for anti-T. gondii antibodies by the indirect fluorescent antibody test (IFAT), enzyme-linked immunosorbent assay (ELISA), modified agglutination test (MAT), and indirect hemagglutination test (IHAT). Tissue samples from all animals were analyzed by histopathology, immunohistochemistry and mouse bioassay (gold standard). Fifty-four chickens were positive for T. gondii in the bioassay. The sensitivity and specificity of the different tests were, respectively, 85% and 56% for ELISA; 80% and 52% for IFAT; 76% and 68% for MAT; 61% and 80% for IHAT; 7% and 98% for immunohistochemistry, and 6% and 98% for histopathology. The MAT was the most effective method for the diagnosis of T. gondii infection in chickens, followed by ELISA. Histopathology and immunohistochemistry are useful tools for the diagnosis of T. gondii infection in chickens due to their specificity.