Factors associated with survival, laminitis and insulin dysregulation in horses diagnosed with equine pituitary pars intermedia dysfunction.

BACKGROUND: Pituitary pars intermedia dysfunction (PPID) is a commonly described endocrine disorder in higher latitudes of the Northern hemisphere but the description of the disease at lower latitudes and in the Southern hemisphere is limited. OBJECTIVES: Document the clinical features of PPID at different Australian latitudes and climates, and investigate factors associated with survival, laminitis and insulin dysregulation (ID). STUDY DESIGN: Retrospective study of 274 equids from eight institutions across Australia. METHODS: A diagnosis of PPID was based on endogenous ACTH, overnight dexamethasone suppression test, thyrotropin-releasing hormone stimulation test or necropsy. Clinical and clinicopathologic characteristics of PPID and therapeutic responses were investigated. Laminitis was diagnosed by radiographic or histologic changes and ID was diagnosed based on endogenous insulin, an oral glucose test or a 2-step insulin-response test. RESULTS: Being a pony, having a higher body condition score and pergolide administration were associated with survival. The clinical presentation of PPID changed with latitude and climate, with anhidrosis and polyuria/polydipsia more commonly recognised at lower latitudes. Laminitis was diagnosed in 89.9% of cases and ID was present in 76.5% of cases in which they were investigated. MAIN LIMITATIONS: Despite the sample size, the lack of uniform testing at all locations (primary or referral cases) and the incompleteness of data sets limited the power of the statistical analyses. CONCLUSIONS: PPID can present with variable signs at different latitudes and climates, and ID should be investigated in equids diagnosed with PPID. Adequate body condition and administration of pergolide are fundamental in PPID management.

Circannual variability in adrenocorticotropic hormone responses to administration of thyrotropin-releasing hormone in clinically normal horses in Australia.

Thyrotropin releasing hormone (TRH)-stimulation testing for pituitary pars intermedia dysfunction (PPID) in horses is only recommended at certain times of the year. Current diagnostic cut-off values reflect testing in the northern hemisphere during this time. The aims of this study were to evaluate TRH stimulation testing during two different phases of the circannual pituitary cycle and to determine whether diagnostic cut-off values developed in the northern hemisphere are appropriate in Australia. Thirteen clinically normal horses at Perth, Western Australia, and 23 horses at Townsville, Queensland, Australia, had TRH stimulation tests performed at two different time points during the circannual pituitary cycle. At both locations, post-TRH adrenocorticotropic hormone (ACTH) concentrations were significantly different between testing time points (Perth: P=0.001; Townsville: P<0.0001). In Perth, the mean ACTH concentrations 10min post-TRH in September and March were 51.4pg/mL (95% confidence interval, CI, 46.4-56.4pg/mL) and 248.5pg/mL (95% CI 170.2-326.9pg/mL), respectively. The median percentage change in ACTH concentrations in March was 361.9%. In Townsville, the mean ACTH concentrations 30min post-TRH in September and April were 35.3pg/mL (95% CI 29.6-40.9pg/mL) and 112.3pg/mL (95% CI 93.4-131.2pg/mL), respectively. The median percentage change in ACTH concentrations in April was 144.7%. The ACTH cut-off value after TRH stimulation in normal horses in September in Perth and Townsville was similar to the values established in the northern hemisphere. However, TRH stimulation testing in March/April was highly variable at both locations.

Multiple neuronal pathologies are common in young patients with pathologically proven Frontotemporal lobar degeneration.

AIMS: The past decade has seen a surge in studies identifying mixed pathologies in elderly populations. Importantly however, few studies have focussed on mixed pathology in Frontotemporal Lobar Degeneration (FTLD), particularly in younger cases. METHODS: The present study examined concomitant pathological neuronal inclusions of TDP-43, hyperphosphorylated tau and α-synuclein protein in the anterior cingulate, hippocampus and entorhinal cortex in young (≤65 years at death) vs. elderly (≥80 years at death) cases with pathologically confirmed FTLD (n = 52) or Alzheimer's disease (AD) (n = 47). RESULTS: Our results demonstrate the presence of additional neuronal pathologies not associated with the primary pathological diagnosis in a similar proportion of young and elderly FTLD cases, indicating that disease drivers rather than age are the major risk factors for multiple neuronal pathologies in FTLD. When only sporadic FTLD cases were considered, the proportion of cases with multiple neuronal pathologies across FTLD age cohorts remained similar, indicating that multiple neuronal pathologies in young FTLD cases is not driven by known genetic mutations. In contrast to these findings in FTLD, a significantly greater proportion of elderly compared to young AD cases demonstrated multiple neuronal pathologies, corroborating literature. CONCLUSIONS: In summary, the present study reports for the first time that age is not a major risk factor for multiple neuronal pathologies in FTLD. These findings have significant implications for the development of protein-specific biomarkers and treatments for FTLD, and underscore the need for further research to identify the disease factors involved in driving multiple neuronal pathologies in FTLD.

The Effect of Geographic Location on Circannual Adrenocorticotropic Hormone Plasma Concentrations in Horses in Australia.

BACKGROUND: Longitudinal evaluation of plasma endogenous ACTH concentration in clinically normal horses has not been investigated in the Southern Hemisphere. OBJECTIVES: To longitudinally determine monthly upper reference limits for plasma ACTH in 2 disparate Australian geographic locations and to examine whether location affected the circannual rhythm of endogenous ACTH in the 2 groups of horses over a 12-month period. ANIMALS: Clinically normal horses <20 years of age from 4 properties (institutional herd and client owned animals) in Perth (n = 40) and Townsville (n = 41) were included in the study. METHODS: A prospective longitudinal descriptive study to determine the upper reference limit and confidence intervals for plasma ACTH in each geographic location using the ASVCP reference interval (RI) guidelines, for individual months and monthly groupings for 12 consecutive months. RESULTS: Plasma endogenous ACTH concentrations demonstrated a circannual rhythm. The increase in endogenous ACTH was not confined to the autumnal months but was associated with changes in photoperiod. During the quiescent period, plasma ACTH concentrations were lower, ≤43 pg/mL (upper limit of the 90% confidence interval (CI)) in horses from Perth and ≤67 pg/mL (upper limit of the 90% CI) in horses from Townsville, than at the acrophase, ≤94 pg/mL (upper limit of the 90% CI) in horses from Perth, ≤101 pg/mL (upper limit of the 90% CI) in horses from Townsville. CONCLUSIONS AND CLINICAL IMPORTANCE: Circannual rhythms of endogenous ACTH concentrations vary between geographic locations, this could be due to changes in photoperiod or other unknown factors, and upper reference limits should be determined for specific locations.

Influence of age on surfactant isolated from healthy horses maintained on pasture.

BACKGROUND: Surfactant alterations are described in horses after exercise, anesthesia, and prolonged transport, in horses with recurrent airway obstruction, and in neonatal foals. The effect of horse age or bronchoalveolar lavage fluid (BALF) sample characteristics on surfactant is unknown. OBJECTIVES: To evaluate surfactant phospholipid composition and function in healthy horses, and to investigate the influence of age and BALF sample characteristics on surfactant. ANIMALS: Seventeen healthy horses 6-25 years of age maintained on pasture year-round. METHODS: BALF was collected by standard procedures and was assessed for recovery volume, nucleated cell count (NCC), and cytology. Cell-free BALF was separated into crude surfactant pellet (CSP) and surfactant supernatant (Supe) by ultracentrifugation. Phospholipid and protein content were determined from both fractions. CSP phospholipid composition was analyzed by high-performance liquid chromatography with an evaporative light scatter detector. Surface tension of CSP was evaluated with a pulsating bubble surfactometer. Regression analysis was used to evaluate associations between age, BALF sample characteristics, and surfactant variables. RESULTS: Results and conclusions were derived from 15 horses. Increasing age was associated with decreased phospholipid content in CSP but not Supe. Age did not affect protein content of CSP or Supe, or surfactant phospholipid composition or function. Age-related surfactant changes were unaffected by BALF recovery percentage, NCC, and cytological profile. CONCLUSIONS AND CLINICAL IMPORTANCE: Older horses have decreased surfactant phospholipid content, which might be because of age-related pulmonary changes. Surfactant composition is unaffected by BALF sample characteristics at a BALF recovery percentage of at least 50%.

Nonradiative de-excitation mechanisms in long-lived erbium(III) organic compounds ErxY1-x[(p-CF3-C6F4)2PO2]3.

We have performed a spectroscopic study of ErxY1-x[(p-CF3-C6F4)2PO2]3 aimed at understanding nonradiative de-excitation mechanisms. These fluorinated compounds have a long lifetime for the erbium 4I13/2-->4I15/2 emission at lambda approximately 1540 nm, but the lifetime increases with decreasing x. We have studied the lifetime as a function of morphology, temperature, and high hydrostatic pressure. We have demonstrated the occurrence of energy migration and calculated the corresponding activation energy. Moreover, using high pressure techniques, we provide evidence that cross-relaxation involving energy transfer from an excited erbium in the 4I13/2 promoting a neighbor in the same state to 4I9/2 is the dominant mechanism at ambient conditions for short erbium-erbium distances. The model explains the observed dynamics of excited states in the series and is tested against the Yb[(p-CF3-C6F4)2PO2]3 compound.

Catheters: a review of the selection, utilisation and complications of catheters for peripheral venous access.

Intravenous catheters are used for the administration of medications and fluids and are an integral part of veterinary practice. The aim of catheter use is to optimise administration of medication and minimise complications such as thrombus formation, thrombophlebitis and sepsis. Catheters made from teflon are less flexible, less durable and stimulate more tissue reaction than polyurethane or silicon. However silicon catheters are more expensive and complicated to insert. Generally, for veterinary practice, the biostability and cost of polyurethane catheters make them preferable for short and long-term use. The smallest diameter catheter should be selected to minimise internal vessel wall contact and irritation without compromising medication delivery. The site of insertion varies with individual preference, vessel access and patient compliance. The jugular, cephalic, saphenous, ear, lateral thoracic and subcutaneous abdominal veins are accessible. Hair removal and a thorough aseptic skin preparation should be performed prior to catheter insertion. Daily maintenance is required to detect complications and maximise catheter longevity. Potential complications include thrombus formation, thromboembolism, bacterial colonisation and septicaemia, blood loss and air embolism. Permanent or transient skin dwelling bacteria are commonly isolated if sepsis occurs. The development of novel antiseptic and antibiotic impregnated catheters may reduce the complications associated with catheter infection in the future.

Suture materials: composition and applications in veternary wound repair.

Suture materials play an important role in veterinary surgery by providing support for healing tissues during wound repair. As there is no single ideal suture material, clinicians must compromise on some properties when selecting a material for a specific purpose. By reviewing the characteristics of absorbable and non-absorbable materials, general recommendations can be made on their usage in skin, fascia, viscera and other tissues.

The lumbosacral lucent cleft.

BACKGROUND: The lumbosacral lucent cleft was first described in association with traumatic injuries to the neck. However, we have observed this sign to be present in patients with no precursor of trauma, and we reviewed the incidence of lucent cleft sign in our local population and any characteristic features of the lucent cleft. METHODS: Four-hundred and thirty lumbosacral spine radiographs were examined prospectively over an 8-month period, with correlation with clinical findings. Follow-up radiographs were obtained at 1, 3 and 6 months for patients with the lucent cleft sign. FINDINGS: Nineteen patients (4.4%) were found to have lucent clefts in their lumbosacral spine X-rays. No significant change in the number and features to the lucent clefts was noted even when the symptoms had resolved after 6 months. All the lucent clefts were linear, horizontally oriented and located at the anterior edge of the adjacent vertebral body. CONCLUSION: The lucent cleft sign in the spine, which has so far been described in association with has spinal trauma may be completely innocuous in patients with little or no symptoms.

The periodic medical examination in the Republic of Singapore Air Force--a review.

Aeromedical Examinations (AMEs) have been done in the Republic of Singapore Air Force (RSAF) since its beginning for licensing and monitoring health status of essential personnel. The rapid progress in scientific advances and medical costs of recent years prompted a re-evaluation of the AME as a preventive tool, both in accident prevention and health promotion. A retrospective cohort study of 233 males spanning the time they joined the Air Force until 1990 was done and a descriptive analysis of the cohort with the incidence rate of cases picked up during this period was used as an indicator of usefulness of the AME. In the follow-up period of 2997 person-years, a small number of cases were picked up which resulted in two pilots being grounded permanently. Most procedures were found to be useful to varying extent except the routine chest X-rays which was found to be ineffective. Trends of biodata resulting from serial examinations are useful in planning and evaluation of intervention and health education programme, but only if the baseline measurements are accurate, hence quality control at all stages is important. The AME can be an effective tool for prevention if designed appropriately. Screening tests included must be scientific and the logic for selecting tests must be convincing. Most importantly, it is suggested that a clear and detailed medical history is the most useful component for early detection of problems. This is facilitated by a strong bond and rapport between doctors and subjects to ensure that the information is forthcoming and honest.