Pulmonary artery dissection following pulmonary balloon valvuloplasty in dogs.

INTRODUCTION/OBJECTIVES: Pulmonary artery dissection is a rare complication following balloon valvuloplasty for pulmonic stenosis. We sought to report the rate of this complication in dogs and describe the demographic, clinical, procedural, and outcome data in affected dogs. ANIMALS, MATERIALS AND METHODS: Medical records at a single academic institution between 2002 and 2021 were reviewed for dogs with pulmonic stenosis treated by a balloon valvuloplasty. Dogs were included for evaluation if there was evidence of pulmonary artery dissection on echocardiography or necropsy following balloon valvuloplasty. The demographic, clinical, surgical, and follow-up information were then recorded. RESULTS: Six dogs were included from 210 balloon valvuloplasty procedures for pulmonic stenosis giving a 3.9% rate of pulmonary dissection. There was a variety of signalment, pulmonary valve morphologies, and balloon catheter types used in each dog. All dogs had severe pulmonic stenosis (median pressure gradient of 208 mmHg, range 94-220 mmHg) with 5/6 dogs having a pressure gradient >144 mmHg. The median balloon to pulmonary valve annulus ratio was 1.35 (range 1.25-1.5). Three dogs died perioperatively, and three dogs were alive at follow up 3.3, 4.0, and 4.1 years postoperatively. CONCLUSION: Pulmonary artery dissection is a rare complication following balloon valvuloplasty for pulmonic stenosis. Extreme elevations in preoperative pulmonary valve flow velocity were common. Prognosis is variable, with a potential 50% perioperative survival rate, but extended survival times were noted in those patients discharged from hospital.

Transvenous detachable coiling of patent ductus arteriosus in small dogs.

OBJECTIVE: To report on transvenous detachable coiling in small dogs deemed ineligible for traditional transarterial patent ductus arteriosus occlusion and compare transthoracic echocardiographic and angiographic measurements to determine their equivalence. MATERIALS AND METHODS: A retrospective study of 35 dogs that underwent transvenous coiling of a patent ductus arteriosus. Demographic information, echocardiographic and angiographic studies, surgery reports, and follow-up evaluation of residual flow were obtained. A Bland-Altman analysis was used to compare echocardiographic and angiographic measurements of the minimal ductal diameter (Echo-MDD, Ang-MDD) and ampulla diameter (Echo-A, Ang-A). RESULTS: Thirty-four of 35 dogs had successful deployment of a coil, with one dog undergoing occlusion with a different device after the exteriorized coil pulled through the ductus. Complete occlusion was achieved in 18 dogs within 24 h; four dogs were lost to follow-up, and the remaining 12 dogs had no residual flow or a significant reduction in shunting with normalization in cardiac chamber dimensions by a median of 99 days. Thirty percent of dogs (11/35) experienced perioperative complications of which 10 were minor complications. The analysis of 26 dogs with both echocardiographic and angiographic ductal measurements showed a -0.14 mm mean difference (95% limits of agreement -1.08 to 0.8 mm) in minimal ductal diameter and -0.68 mm mean difference (95% limits of agreement -2.73 to 1.37 mm) in ampulla diameter. CONCLUSIONS: Dogs less than 3 kg deemed too small for transarterial occlusion can successfully undergo transvenous coil embolization of patent ductus arteriosus.

Transmembrane stent placement for cor triatriatum dexter in six dogs.

OBJECTIVES: Report the long-term outcomes following transmembrane stent placement as a therapy for Cor Triatriatum Dexter (CTD). MATERIALS AND METHODS: Retrospective case series including six dogs with CTD treated with transmembrane stent placement. Follow-up information was obtained including the persistence of presenting clinical signs, additional therapies required, and survival. RESULTS: The median follow-up time was 24 months (range 15-76 months). Long-term outcome was deemed excellent in four dogs (67%), good/fair in one dog (17%), and poor in one dog (17%). Three dogs had persistence of clinical signs of variable severity. These three dogs were Labrador Retrievers or their crosses with varying degrees of tricuspid valve dysplasia (TVD), two of which also had a right to left shunting patent foramen ovale (PFO). One of these three dogs died 23 months post-stent placement during attempted open-heart repair of the TVD and PFO. Another is alive 15 months post-operatively stable on medical therapy for right-sided congestive heart failure secondary to TVD. The final dog demonstrated improved but persistent mild exercise intolerance up to 76 months post-operatively associated with mild TVD and a concurrent PFO. CONCLUSIONS: Transmembrane stent placement for CTD is a viable long-term treatment option with improvement or resolution of clinical signs. In the presence of concurrent congenital heart disease, specifically Labradors with TVD, additional therapies may be necessary with a corresponding impact on prognosis.

Coronary arterial compression testing by simultaneous balloon valvuloplasty and coronary angiography in an English bulldog with pulmonary valve stenosis.

A 4-year-old male neutered English bulldog presented for heart murmur evaluation. Echocardiography identified severe pulmonic stenosis (an echocardiography-derived transpulmonary pressure gradient of 100 mmHg), and computed tomography confirmed the presence of an anomalous coronary artery with a prepulmonic course of the left coronary artery arising from the right coronary ostium. Before artificial pulmonic valve implantation, a coronary compression test was performed. A simultaneous aortic root angiogram and pulmonic balloon valvuloplasty revealed complete occlusion of the circumflex branch. Artificial valve implantation was aborted with concern for fatal coronary compression after implantation. Coronary compression testing is a critical component of the evaluation before catheter-based implantation of conduits across the pulmonic valve.

Left pulmonary arterial branch interruption with concurrent coarctation of the right pulmonary artery in a dog.

This case report describes a rare disorder of a left pulmonary artery interruption with concurrent coarctation of the right pulmonary artery in a dog. A 5-year-old, male neutered, mixed-breed dog presented for evaluation of an asymptomatic heart murmur. Echocardiography and computed tomography revealed complete interruption of the proximal left pulmonary artery and coarctation of the right pulmonary artery. Collateral circulation to the left lung field was provided by a dilated bronchoesophageal artery with evidence of left pulmonary hypoplasia. Pulmonary artery interruption and coarctation is rarely reported in the veterinary literature.

Echocardiographic parameters for the assessment of congestive heart failure in dogs with myxomatous mitral valve disease and moderate to severe mitral regurgitation.

The objective of this study was to evaluate the influence of congestive heart failure (CHF) on echocardiographic variables in dogs with moderate or severe mitral valve regurgitation (MR) secondary to myxomatous mitral valve disease (MMVD). The secondary objective was to investigate the preliminary use of left ventricular early inflow-outflow index (LVEIO) and L-waves as indicators of CHF. Forty-five dogs with moderate or severe MR without (n = 23) or with (n = 22) CHF were retrospectively included. Echocardiographic variables of elevated left ventricular (LV) filling pressures and cardiac function, LVEIO and the presence of L-waves were obtained and statistically compared between the two groups. On general linear model analysis, mitral inflow peak E-wave velocity, E:A ratio, ratio of E to isovolumic relaxation time (IVRT) and LVEIO were increased, while left atrium (LA) fractional shortening was reduced, in dogs with CHF. Peak E-wave velocity, peak A-wave velocity, E:A ratio, LA minimum diameter, LA diameter before the P-wave, LA fractional shortening and LVEIO were found to be predictive of CHF. The absence of L-waves indicated a reduced risk of CHF. Several echocardiographic variables may be useful in identifying elevated LV filling pressures, consistent with CHF, in dogs with moderate and severe MR. Left ventricular early inflow-outflow index and L-waves might be of interest as clinical and prognostic markers in dogs with MMVD and require further investigation.

Reduced metabolic rate accompanies the hemorrhage-induced hypothermia in conscious rats.

The mechanism for the hemorrhage-induced drop in body temperature is unknown. This study determined the alterations in cutaneous heat exchange and metabolic heat production caused by a moderate hemorrhage in conscious rats. Chronically instrumented rats were subjected to a 16 ml/kg hemorrhage, followed by a 4-h recovery period, while monitoring body core temperature and cutaneous temperature. Cutaneous heat transfer was disrupted by housing the animals at an elevated (28 degrees C) ambient temperature. A separate group of experiments measured the change in oxygen consumption in the post-hemorrhage period. Moderate hemorrhage caused a drop in body core temperature which stabilized at 0.7+/-0.3 degrees C below control in the second hour following hemorrhage. Disruption of cutaneous heat exchange by reducing the thermal gradient did not diminish the hemorrhage-induced hypothermia. Hemorrhage caused a significant decline of oxygen consumption (-0. 21+/-0.05 ml O(2)/g per h). This 16% drop in resting oxygen consumption was prevented by immediately retransfusing the aspirated blood back into the rat. These data indicate that a decrease in metabolic heat production mediates the drop in body core temperature caused by moderate hemorrhage in conscious rats.

Reduced oxygen consumption precedes the drop in body core temperature caused by hemorrhage in rats.

This study examines the early time course in core temperature change and oxygen consumption at 4 levels of hemorrhage. Chronically instrumented rats were acclimatized to a respirometry chamber for 30 min. The rats were briefly (10 min) removed from the chamber for a fixed volume hemorrhage of 0 mL/kg (sham), 8 mL/kg, 16 mL/kg, 24 mL/kg, or 32 mL/kg. Rats were then returned to the chamber, and oxygen consumption and body core temperature were monitored for the next 2 h. Oxygen consumption (control 1.26 mL O2/g/h) fell significantly 5 min after hemorrhage in all but the sham and 8 mL/kg hemorrhage groups, with the decrease proportional to the hemorrhage volume. The 32 mL/kg hemorrhage group showed the greatest decrease, to 0.47 mL O2/g/h. Body core temperature (control 37.5 degrees C) fell more gradually, declining to 35.6 degrees C 110 min after the 24 mL/kg hemorrhage, and to 33.2 degrees C at 6 h after the 32 mL/kg hemorrhage. In the 16 mL/kg hemorrhage group, oxygen consumption fell significantly by 5 min after hemorrhage, but a drop in body temperature was not seen until 25 min after hemorrhage. The data from this study indicate that the drop in core temperature does not cause the observed decrease in oxygen consumption. In fact, the timing and magnitude of the drop in oxygen consumption indicate that the reduced metabolic rate may mediate the hemorrhage-induced drop in body core temperature in conscious rats.

IR and raman spectra of two layered aluminium phosphates Co(en)3Al3P4O16.3H2O and.

The FT IR and FT Raman spectra of Co(en)3Al3P4O16.3H2O (compound I) and [NH4]3[Co(NH3)6]3[Al2 (PO4)4]2.2H2O (compound II) are recorded and analysed based on the vibrations of Co(en)(3)3+, Co(NH3)(6)3+, NH4, Al-O-P, PO3, PO2 and H2O. The observed splitting of bands indicate that the site symmetry and correlation field effects are appreciable in both the compounds. In compound I, the overtone of CH2 deformation Fermi resonates with its symmetric stretching vibration. The NH4 ion in compound II is not free to rotate in the crystalline lattice. Hydrogen bonding of different groups is also discussed.

Compliance with anti-tuberculosis preventive therapy among 6-year-old children.

There are no published data regarding compliance with anti-tuberculosis preventive therapy among children in Australia and limited published data worldwide. This study aimed to determine the compliance rate among 6-year-old children prescribed preventive therapy for tuberculosis infection. A prospective cohort study was conducted on 78, 6-year-old children prescribed antituberculosis preventive therapy. Compliance was measured by compliance with prescribed preventive therapy as reported by parents who were administered questionnaires on completion of the course. In a subsample of 44 children, the proportion of children who complied with scheduled visits to the hospital, and pharmacy records of isoniazid dispensed were used as measures of compliance. Questionnaire data indicated a reported compliance rate for completion of the 6-month course of preventive therapy of 70.5% (55 children). For those 55 who reported completing the full course, 91% reported missing less than 1 tablet per week. In the subsample of 44 children, only 59% attended all follow-up clinic visits, and 54% collected all 6 months of isoniazid prescribed. Compliance with antituberculosis preventive therapy is suboptimal. Improved methods to measure compliance and strategies to optimise compliance with preventive therapy is required.

Prevalence of tuberculosis infection among primary school-entry children in Sydney.

A cross-sectional survey of 2044 Year I children enrolled in 24 primary schools was performed to determine the prevalence of tuberculosis (TB) infection. Of the 2044 children, 1458 (71 per cent) were Mantoux-tested and 1452 Mantoux reactions were read. Of the total, 6.5 per cent were Mantoux-positive; 17.8 per cent of overseas-born children and 2.8 per cent of Australian-born children were Mantoux-positive (relative risk for overseas-born 6.9, 95 per cent confidence interval 4.2 to 9.6). In the areas of Sydney where the study was conducted, there is a high prevalence of TB infection (non-contagious) among overseas-born children in the five- to seven-year age group. This indicates that there may be a large pool of infected children, a proportion of whom are at risk of developing active (contagious) adult-type TB in the future. These data, with other published data on TB infection rates in other age groups, can contribute to the estimation of the size of the infected pool in Australia to allow rational decisions regarding control of TB in Australia, including the possibility of introducing Mantoux screening and preventive therapy programs for high-risk groups.

The ontogeny of oxygen consumption and ventilation in the Adélie penguin, Pygoscelis adeliae.

Although both energy metabolism and ventilation parameters are highly size dependent in adult birds, the usual scaling relationships with mass do not hold in hatchlings or in growing chicks. In Adélie penguins, three distinct behavioral phases during growth and development are reflected in the ontogeny of metabolism and ventilation. Metabolic intensity increases in the nestling phase (age 0-11 days), stabilizes during the creche phase (14-40 days), and decreases in fledglings (40-55 days) and adults. Minimal respiratory frequency does not change with mass in nestlings, decreases in creche chicks, and falls abruptly in fledglings and adults. Mass-specific standard tidal volume and mass-specific standard minute volume do not change with mass in nestlings, increase abruptly at 14 days, decline with increasing mass in creche chicks, and are not correlated with mass in fledglings and adults. Oxygen extraction at minimal frequency increases with increasing mass in nestlings and in creche chicks, and it declines with increasing mass in fledglings and adults. At any given age, usually Adélie penguins accommodate changing thermogenic demand primarily by adjusting minute volume rather than oxygen extraction.

Weather, microclimate, and energy costs of thermoregulation for breeding Adélie Penguins.

We measured meteorological conditions and estimated the energy costs of thermoregulation for young and adult Adélie Penguins (Pygoscelis adeliae) at a breeding colony near the Antarctic Peninsula. Air temperatures averaged < 5°C and strong winds were frequent. Operative temperatures (Te) for adults ranged from -8 to 28°C, averaging 5-6°C, for the period from courtship to fledging of chicks. The average energy cost of thermoregulation (Cth) for adult penguins was equivalent to 10-16% of basal metabolism. Cth comprised about 15% of the estimated daily energy budget (DEB) of incubating adults, but only about 1% of the DEB of adults feeding chicks. The Te's for chicks older than 14 days ranged from 0 to 31°C, averaging 8.0 C. The Cth for downy chicks ranged from about 31% of minimal metabolic rate (MMR) in 1 kg chicks to about 10% of MMR in 3 kg chicks. Between initial thermal independence (age 12-14 days) and the cessation of parental feeding (age 35-40 days), chicks use about 10-11% of assimilated energy for thermoregulation. Cth is equivalent to about 17% of the MMR of fledglings during their 2-3 week fast. We observed no indication of thermal stress (i.e., conditions in which birds cannot maintain stable Tb) in adults and no indication of cold stress in any age class. However, on clear, calm days when air temperature exceeds 7-10°C for several hours, downy chicks are vulnerable to lethal hyperthermia.

Homeothermic response to reduced ambient temperature in a scarab beetle.

Elephant beetles (Megasoma elephas; Scarabaeidae) weighing from 10 to 35 grams, respond homeothermically when ambient temperature is reduced below about 20 degrees C in the laboratory. This metabolic response is not associated with locomotion or any other overt activity. Warming is initiated when the body temperature reaches an apparent set point of 20 degrees to 22 degrees C. Unlike the case for euthermic birds and mammals, energy metabolism and body temperature in these beetles are conspicuously oscillatory, with a given cycle in oxygen consumption peaking before the corresponding cycle in body temperature.