Mechanistic basis for the gas exchange threshold in Thoroughbred horses.

The exercising Thoroughbred horse (TB) is capable of exceptional cardiopulmonary performance. However, because the ventilatory equivalent for O2 (VE/VO2) does not increase above the gas exchange threshold (Tge), hypercapnia and hypoxemia accompany intense exercise in the TB compared with humans, in whom VE/VO2 increases during supra-Tge work, which both removes the CO2 produced by the HCO buffering of lactic acid and prevents arterial partial pressure of CO2 (PaCO2) from rising. We used breath-by-breath techniques to analyze the relationship between CO2 output (VCO2) and VO2 [V-slope lactate threshold (LT) estimation] during an incremental test to fatigue (7 to approximately 15 m/s; 1 m x s(-1) x min(-1)) in six TB.

NO inhalation reduces pulmonary arterial pressure but not hemorrhage in maximally exercising horses.

In horses, the exercise-induced elevation of pulmonary arterial pressure (Ppa) is thought to play a deterministic role in exercise-induced pulmonary hemorrhage (EIPH), and thus treatment designed to lower Ppa might reasonably be expected to reduce EIPH. Five Thoroughbred horses were run on a treadmill to volitional fatigue (incremental step test) under nitric oxide (NO; inhaled 80 ppm) and control (N(2), same flow rate as per NO run) conditions (2 wk between trials; order randomized) to test the hypothesis that NO inhalation would reduce maximal Ppa but that this reduction may not necessarily reduce EIPH. Before each investigation, a microtipped pressure transducer was placed in the pulmonary artery 8 cm past the pulmonic valve to monitor Ppa.

Sarco/endoplasmic reticulum calcium ATPase-2 expression is regulated by ATF6 during the endoplasmic reticulum stress response: intracellular signaling of calcium stress in a cardiac myocyte model system.

The recently described transcription factor, ATF6, mediates the expression of proteins that compensate for potentially stressful changes in the endoplasmic reticulum (ER), such as reduced ER calcium. In cardiac myocytes the maintenance of optimal calcium levels in the sarcoplasmic reticulum (SR), a specialized form of the ER, is required for proper contractility. The present study investigated the hypothesis that ATF6 serves as a regulator of the expression of sarco/endoplasmic reticulum calcium ATPase-2 (SERCA2), a protein that transports calcium into the SR from the cytoplasm.

Farm-management and milking practices associated with the presence of Listeria monocytogenes in New York state dairy herds.

Knowledge of the relationship between dairy herd management and milking practices with the occurrence of Listeria monocytogenes on dairy farms might assist in the development of intervention strategies aimed at eliminating this organism at the pre-harvest dairy-food-production level. This paper represents a first step towards that goal. We carried out a cross-sectional study to identify farm factors that were associated with isolation of L.

Efficacy of nasal strip and furosemide in mitigating EIPH in Thoroughbred horses.

The purpose of this investigation was to study the effects of an equine nasal strip (NS), furosemide (Fur), and a combination of both (NS + Fur) on exercise-induced pulmonary hemorrhage (EIPH) at speeds corresponding to near-maximal effort. Five Thoroughbreds (526 +/- 25 kg) were run on a flat treadmill from 7 to 14 m/s in 1 m x s(-1) x min(-)1 increments every 2 wk (treatment order randomized) under control (Con), Fur (1 mg/kg iv 4 h prior), NS, or NS + Fur conditions. During each run, pulmonary arterial (Ppa) and esophageal (Pes) pressures were measured.

Effect of L-NAME on oxygen uptake kinetics during heavy-intensity exercise in the horse.

There is evidence that oxidative enzyme inertia plays a major role in limiting/setting the O(2) uptake (VO(2)) response at the transition to higher metabolic rates and also that nitric oxide (NO) competitively inhibits VO(2) within the electron transport chain. To investigate whether NO is important in setting the dynamic response of VO(2) at the onset of high-intensity (heavy-domain) running in horses, five geldings were run on a treadmill across speed transitions from 3 m/s to speeds corresponding to 80% of peak VO(2) with and without nitro-L-arginine methyl ester (L-NAME), an NO synthase inhibitor (20 mg/kg; order randomized). L-NAME did not alter (both P > 0.

Rat muscle microvascular PO2 kinetics during the exercise off-transient.

Dependent upon the relative speed of pulmonary oxygen consumption (VO2) and blood flow (Q) kinetics, the exercise off-transient may represent a condition of sub- or supra-optimal perfusion. To date, there are no direct measurements of the dynamics of the VO2/Q relationship within the muscle at the onset of the work/recovery transition. To address this issue, microvascular PO2 (PO2,m) dynamics were studied in the spinotrapezius muscles of 11 female Sprague-Dawley rats (weight approximately 220 g) during and following electrical stimulation (1 Hz) to assess the adequacy of Q.

A comparison of fusion rates between single-level cervical corpectomy and two-level discectomy and fusion.

A single corpectomy and strut grafting has been proposed as an alternative to performing two-level adjacent discectomies with multiple grafts to produce superior fusion rates. The purpose of this study was to compare the clinical and radiographic success of two-level discectomy and fusion with anterior cervical plate fixation compared with a single-level corpectomy. Fifty-two patients were treated with either a two-level adjacent anterior cervical discectomy and fusion with cervical plating, or by a single-level corpectomy and plate.

Familial gonadotropin-releasing hormone resistance and hypogonadotropic hypogonadism in a family with multiple affected individuals.

Objective: To characterize the phenotype of idiopathic hypogonadotropic hypogonadism due to compound heterozygous GnRHR gene mutations (Arg262Gln/Tyr284Cys).

Design: Retrospective review.

Setting: Tertiary medical center.

The social context of health selection: a longitudinal study of health and employment.

Health selection out of the labour force has received considerable attention by analysts attempting to disentangle the "true" biological dimensions of ill-health from its social meaning. Rejecting this dualistic separation, we argue that the effect of health on labour force participation is an inherently social process reflecting differential access to material and symbolic rewards that are structured by social position. Using longitudinal data from the US-based Panel Study of Income Dynamics, we examine the extent to which structural arrangements, including those designated by gender, race, education and age, differentially affect the risk of a labour market exit when health is compromised.

Helicobacter pylori infection in the cat: evaluation of gastric colonization, inflammation and function.

Background: Further elucidation of the consequences of Helicobacter pylori infection on gastric mucosal inflammation and gastric secretory function would be facilitated by an animal model that is susceptible to infection with H. pylori, is broadly similar in gastric physiology and pathology to people, and is amenable to repeated non-invasive evaluation. The goal of this study was to examine the interrelationship of bacterial colonization, mucosal inflammation and gastric secretory function in cats with naturally acquired H.

Comparative genetic characterization of Listeria monocytogenes isolates from human and animal listeriosis cases.

Listeria monocytogenes isolates from human sporadic and epidemic cases (n=119) and from animal cases (n=76) were characterized by automated ribotyping and PCR-restriction fragment length polymorphism (PCR-RFLP) typing of the virulence genes actA and hly. This combination of typing methods differentiated 39 distinctive strains, each reflecting a unique combination of ribotypes, hly and actA alleles. Simpson's index of discrimination indicated a high discriminatory ability of ribotyping for both animal (0.

Increased fusion rates with cervical plating for three-level anterior cervical discectomy and fusion.

Study Design: A retrospective review of all patients surgically treated by a single surgeon with a three-level anterior cervical discectomy and fusion with and without anterior plate fixation.

Objectives: To compare the clinical and radiographic success of anterior three-level discectomy and fusion performed with and without anterior cervical plate fixation.

Summary Of Background Data: Previous studies of multilevel cervical discectomies and fusions have shown fusion rates to decrease as the number of surgical levels increases.

Prevalence of enteric zoonotic agents in cats less than 1 year old in central New York State.

A prevalence study of several enteric zoonotic bacterial and parasitic infections was conducted in 263 fecal samples from cats that were between 1 and 12 months old, and that were in humane shelters (n = 149) or were presented to primary-care veterinarians (n = 114). Of these samples, 2 (0.8%) were positive for Campylobacter, 2 (0.

Gender and health: reassessing patterns and explanations.

Recent research on gender and health challenges the prevailing notion of women's generalized health disadvantage by revealing a more variable pattern of gender differences in health. As such differences come to be comprehended as more complex than previously thought, there is a need to reassess the pathways linking gender and health. Using data from a Canadian national probability sample, we examine: (1) gender differences in distress, self-rated health, chronic conditions, restricted activity and heavy drinking; and (2) the role of gender-based differential exposure and vulnerability to chronic stress and life events in explaining observed differences.

Ras reduces L-type calcium channel current in cardiac myocytes. Corrective effects of L-channels and SERCA2 on [Ca(2+)](i) regulation and cell morphology.

Heart failure is associated with dysregulation of intracellular calcium ([Ca(2+)](i)), reduction in myofibrils, and increased activation of Ras, a regulator of signal-transduction pathways. To evaluate the potential effects of Ras on [Ca(2+)](i), we expressed constitutively active Ras (Ha-Ras(V12)) in cardiac myocytes and monitored [Ca(2+)](i) via fluorescence and electrophysiological techniques. Ha-Ras(V12) reduced the magnitude of the contractile calcium transients.

Job insecurity and health.

As employers respond to new competitive pressures of global capitalism through layoffs and the casualization of labor, job insecurity affects a growing number of workers. It appears to harm mental health, but less is known about its effects on physical health and health behaviors and the mechanisms through which it may act. The prevailing individual-centered conceptualization of job insecurity as the perception of a threat to job continuity precludes systematic investigation of the social patterning of its health effects.