Transcatheter closure of aneurysmal perimembranous ventricular septal defect with the canine duct occluder in two dogs.

Congenital membranous ventricular septal aneurysm has been reported in dogs and can be associated with a perimembranous ventricular septal defect (VSD). The windsock-like ventricular septal aneurysm is formed by tissue of the membranous ventricular septum and portions of the septal leaflet of the tricuspid valve. We report two dogs that underwent transcatheter closure of perimembranous VSD associated with membranous ventricular septal aneurysm using a commercial device marketed for transcatheter closure of patent ductus arteriosus, the canine duct occluder. Partial closure was achieved in the first dog with reduction in left heart dimensions documented on echocardiography both at one day and nine months after procedure. In the second dog, three-dimensional transesophageal echocardiography, cardiac computed tomography, and a three-dimensionally printed whole heart model were used to evaluate feasibility for transcatheter device closure. Complete closure of the VSD was subsequently achieved. Both cases had good short- to medium-term outcomes, no perioperative complications were observed, and both dogs are apparently healthy and receiving no cardiac medications at 34 months and 17 months after procedure. Transcatheter attenuation of perimembranous VSD with membranous ventricular septal aneurysm is clinically feasible using the canine duct occluder, and multimodal cardiac imaging allows accurate assessment and planning prior to transcatheter intervention for structural heart disease in dogs.

Medial insertion of the patent ductus arteriosus characterized by computed tomography angiography in a cat and dog.

Surgical ligation of a left-to-right shunting patent ductus arteriosus was attempted in two animals. In both cases, a young cat and dog, ligation was complicated by poor visualization of the ductus resulting in unsuccessful ligation. Post-operatively, both the cat and dog underwent computed tomography angiography to characterize the location and morphology of the patent ductus arteriosus. In both cases, computed tomography angiography revealed a left-to-right shunting patent ductus arteriosus with an insertion location medial to the left pulmonary artery branch compared to the typical location. We hypothesize that this atypical location resulted in a difficult surgical visualization from the left thoracotomy approach. Transvenous coil embolization of the duct from the external jugular vein was performed in both cases and resulted in successful occlusion. Variations in the medial-lateral insertion of the ductus arteriosus may have consequences for surgical intervention. If an atypical location of a patent ductus arteriosus is suspected on transthoracic echocardiography, computed tomography angiography prior to ligation may be useful to further define ductal location and help guide the surgical approach.

Trifoliate left atrioventricular valve with and without intact septal structures in four dogs: echocardiographic findings and surgical repair.

Trifoliate left atrioventricular (AV) valve with common atrioventricular junction is considered part of the spectrum of atrioventricular septal defect. This valve morphology is typically associated with defects in the AV septum resulting in communication at the atrial or ventricular level, but has also been described as an isolated defect in the setting of a common AV junction without AV septal defect. Trifoliate left AV valve exhibits a line of apposition between the bridging leaflets that is directed toward the inlet interventricular septum, distinguishing it from isolated mitral valve cleft in which the orientation of the bridging leaflets are toward the left ventricular outflow tract. The echocardiographic findings of four dogs with trifoliate left AV valve are described; two with intact septal structures and two with large ostium primum defects. Three dogs underwent open surgical repair using different approaches depending on the presence or absence of a septal defect. One of these underwent concurrent surgical repair for right AV valve dysplasia. One dog with intact septal structures underwent interventional closure of a concurrent patent ductus arteriosus. Current terminology associated with trileaflet left AV valve malformations is reviewed.

Comparison between the effects of torsemide and furosemide on the renin-angiotensin-aldosterone system of normal dogs.

INTRODUCTION/OBJECTIVES: We hypothesized that torsemide and furosemide, at approximately equipotent dosages (similar diuresis), would have comparable effects on the circulating renin-angiotensin-aldosterone system. ANIMALS, MATERIALS AND METHODS: Six, healthy, middle-aged, male Beagles were randomized to receive torsemide (0.1 mg/kg PO q 12 h), furosemide (2.0 mg/kg PO q 12 h), or placebo for 10 days during three separate periods, separated by a 10-day washout period, in a crossover design. Blood was collected on days 1, 5, and 9 and 24-h urine collection ended on days 2, 6, and 10. After repeated measures analysis and Bonferonni correction, variables with an adjusted p<0.05 were investigated further, using Tukey's method. RESULTS: Twenty-four-hour urine production differed significantly between the diuretics only on day 10, with torsemide causing a 38% greater diuresis than furosemide. There was, however, no significant difference in average 3-day diuresis. There were no significant differences between diuretics in the 24-h urinary excretion of sodium, chloride, or potassium, though furosemide caused less kaliuresis than torsemide. Serum renin, angiotensin II, and aldosterone and the urine aldosterone-to-creatinine ratio were significantly increased in the diuretic groups, as compared to placebo on days 5/6 and 9/10. There were no significant differences in these values between diuretics. Creatinine and blood urea nitrogen concentrations rose comparably in the diuretic groups, remaining within reference intervals in all dogs. CONCLUSIONS: At approximately equipotent dosages (20:1), torsemide and furosemide produced comparable renin-angiotensin-aldosterone system activation. Torsemide's similar potassium excretion profile to furosemide decreases support for a hypothesized mineralocorticoid-receptor blocking capability.

Upper rate behavior in six dogs with dual-chamber pacemakers.

INTRODUCTION: This report provides clinical examples of upper rate behavior in dogs with dual-chamber pacemakers, with suggestions for programming alterations to avoid detrimental upper rate behavior. ANIMALS: Six dogs with dual-chamber pacemakers displaying upper rate behavior at upper atrial tracking rates. METHODS: Medical records of dogs with dual-chamber pacemakers with evidence of upper rate behavior were reviewed retrospectively from two institutions. Two of the six dogs were followed prospectively, and 24 h Holter monitors were placed to evaluate upper rate behavior correlated to programming settings. RESULTS: Pacemaker Wenckebach or 2:1 atrioventricular block was documented in four of six dogs, and automatic mode switch was documented in two of six dogs. Twenty-four-hour Holter monitors placed on two dogs after pacemaker optimization documented a pacemaker Wenckebach window at increased atrial rates with neither dog reaching their respective 2:1 block point throughout the recording period. CONCLUSIONS: Clinicians who implant dual-chamber pacemakers should be aware of upper rate behavior in animal species with high heart rates. Optimal programming of dual-chamber pacemakers can be achieved by selecting programmed timing intervals to limit deleterious upper rate behavior and create a more physiologic ventricular response at maximum tracking rates.

Transcutaneous direct current cardioversion in a foal with lone atrial fibrillation.

There are rare published reports of atrial fibrillation (AF) in foals, all of which are associated with structural heart disease or within the adaptive period of newborns. This report describes a 3-month-old Thoroughbred filly with AF and a structurally normal heart on echocardiography. Medical cardioversion of the foal's AF was attempted with three 20mg/kg doses of quinidine sulfate therapy without success. Timed, transcutaneous, direct current cardioversion was successfully performed using adhesive patches on the midthorax in conjunction with intravenous procainamide at a total dose of 20mg/kg. A normal sinus rhythm was maintained through discharge from the hospital and at recheck 5 months after cardioversion. Transcutaneous direct current cardioversion presents a feasible alternative to quinidine sulfate or transvenous electrical cardioversion in young or lower body weight equids.

Selective inhibition of NAALADase, which converts NAAG to glutamate, reduces ischemic brain injury.

We describe here a new strategy for the treatment of stroke, through the inhibition of NAALADase (N-acetylated-alpha-linked-acidic dipeptidase), an enzyme responsible for the hydrolysis of the neuropeptide NAAG (N-acetyl-aspartyl-glutamate) to N-acetyl-aspartate and glutamate. We demonstrate that the newly described NAALADase inhibitor 2-PMPA (2-(phosphonomethyl)pentanedioic acid) robustly protects against ischemic injury in a neuronal culture model of stroke and in rats after transient middle cerebral artery occlusion. Consistent with inhibition of NAALADase, we show that 2-PMPA increases NAAG and attenuates the ischemia-induced rise in glutamate. Both effects could contribute to neuroprotection. These data indicate that NAALADase inhibition may have use in neurological disorders in which excessive excitatory amino acid transmission is pathogenic.

Plateletapheresis with a next generation blood cell separator.

Procedure time has been identified as the-most important element in apheresis platelet donor retention. Fenwal has developed a next generation apheresis system, the Amicus, with the intent of efficiently producing high platelet yields with low WBC content in much shorter processing times than currently available. This report describes the Amicus and presents results of a clinical trial of an Amicus prototype and a comparison to Fenwal CS 3000+. Thirty Amicus double-needle plateletapheresis procedures were evaluated. Average processing time was 61 +/- 16 min with 63% of the processing times < or = 60 min. The average preplatelet count was 246 +/- 46 x 10(3)/microliter, platelet yield 4.4 +/- 1.2 x 10(11) plt, collection efficiency 73 +/- 14%, platelet collection rate 0.075 +/- 0.016 plt x 10(11)/min and citrate toxicity incidence 3%. A comparison of double-needle procedures, 20 Amicus and 20 CS 3000+, showed that Amicus had significantly shorter (P < .05) processing times (64 +/- 17 vs. 86 +/- 10 min) and higher (P < .05) platelet collection rates (0.070 +/- 0.017 vs. 0.054 +/- 0.018 plt x 10(11)/min) but comparable (P < .05) platelet yields (4.4 +/- 1.4 vs. 4.7 +/- 1.0 x 10(11) plt). Comparison of 13 single and 13 double-needle Amicus procedures showed comparable (P < .05) processing times (71 +/- 13 vs. 65 +/- 18 min), platelet yields (4.7 +/- 1.0 vs. 4.6 +/- 1.5 x 10(11) plt), collection efficiency (74 +/- 7 vs 74 +/- 17%), and platelet collection rates (0.068 +/- 0.020 vs 0.072 +/- 0.018 plt x 10(11)/min). Using normal probability plots of WBC content at 95% confidence level. Amicus can provide products with < 5.0 x 10(6)WBC or < 1.0 x 10(6) WBC in 99.7% or 92.7% of collections, respectively, compared with 69.0% or 44.0%, respectively, for CS 3000+. We found Amicus was able to provide equivalent quantities of platelets with less WBC content in significantly shorter processing times than CS3000+ as well as shown encouraging results for single-needle procedures.

Posttraumatic shock in children: CT findings associated with hemodynamic instability.

Twenty-seven of 1,018 children evaluated with contrast material-enhanced computed tomography (CT) after blunt trauma demonstrated a characteristic hypoperfusion complex. This complex was usually seen in young children (median age, 2 years). CT findings in all 27 patients included a dilated, fluid-filled bowel and abnormally intense enhancement of the bowel wall, mesentery, kidneys, aorta, and inferior vena cava. Twenty-four percent of all children with a Trauma Score of 10 or less and 20% with a Glasgow Coma Score of 6 or less had the hypoperfusion complex. All 27 patients had a normal blood pressure immediately before CT, but five (19%) became hypotensive within 10 minutes of intravenous contrast material administration. Twenty-three children (85%) died. Of 16 children who survived 24 hours, four (25%) developed renal insufficiency. The intense multiorgan enhancement pattern seen in the hypoperfusion complex indicates tenuous hemodynamic stability. Recognition that the constellation of CT findings is due to hypovolemic shock and not to injured viscera helps avoid unnecessary laparotomy.

Infant rats depleted of brain dopamine as neonates exhibit normal independent ingestion.

Weanling or adult rats that have sustained near-total depletions of striatal dopamine (DA) on postnatal Day 3 do not exhibit the severe ingestive deficits seen in comparably depleted adults. The present experiments demonstrated that these animals are capable of ingesting independently, via an intraoral cannula, as early as three days after the depletion. Both activational and ingestive responses to maternal deprivation and intracellular dehydration were virtually identical to the responses of control pups. However, these responses may not be entirely dopaminergically mediated at Day 6 since administration of haloperidol failed to attenuate these behaviors in normal pups. When tested on Day 12, DA-depleted pups continued to exhibit normal ingestive and activational behaviors, despite the fact that haloperidol now suppressed these behaviors in both groups of 12-day-old pups. These findings demonstrate that there is a developmental progression of dopaminergic involvement in the control of independent ingestion and the associated activational responses, yet a near-total depletion of striatal DA is not sufficient to impair the expression of these behaviors.

Renovascular hypertension in children: current concepts in evaluation and treatment.

Since 1981, we have evaluated and treated 22 children with renovascular hypertension (RVH). Seventeen patients had stenosis of their native renal arteries, and five had stenosis of the artery in a transplanted kidney. RVH was caused by fibromuscular dysplasia in 13 patients, by trauma in 2 patients, and by arteritis in 2 patients. Among the patients who had transplanted kidneys, three had technical causes for stenosis and two had stenosis due to rejection. The disease was unilateral in 10 patients, bilateral in 5, and present in a solitary kidney in 7, including the five renal transplants. Diagnostic studies that strongly suggested the presence of renovascular disease were an initial diastolic blood pressure greater than 100 mm Hg, an elevated peripheral vein renin activity level, and an abnormal renal scan if the patient's hypertension was being controlled with an angiotensin-converting enzyme inhibitor (ACEI). Only the renal arteriogram was 100% accurate in confirming the presence of RVH. Percutaneous angiographic correction was attempted in 13 patients and resulted in lasting improvement of the hypertension in five (38%). Surgical revascularization was attempted in 17 children, including the 8 with failed angioplasty, with improvement or cure of the hypertension in 15 patients (88%). Combining percutaneous transluminal angioplasty (PTA) and surgical results gave 20 of 22 patients (91%) with cure or improvement of their hypertension. Four of 27 affected kidneys (15%) could not be revascularized and were removed. We conclude from this series of patients that despite improvements in noninvasive studies, renal arteriogram remains the only study that is 100% accurate in evaluating children for RVH.(ABSTRACT TRUNCATED AT 250 WORDS)

Food intake of rats depleted of dopamine as neonates is impaired by inhibition of catecholamine biosynthesis.

The food intake of rats depleted of brain dopamine (DA) as neonates was markedly reduced by doses of the catecholamine synthesis inhibitor. alpha-methyl-p-tyrosine (AMT), that had little effect on control animals. In contrast, rats depleted of DA as neonates were subsensitive to doses of the DA antagonist, haloperidol, that greatly inhibited food intake in controls. Unexpectedly, low doses of haloperidol potentiated the effects of AMT in both control and DA-depleted animals. These results suggest that activity within residual DA neurons may remain important for the expression of ingestive behavior in rats depleted of DA as neonates although the precise mechanisms may differ from those operating in normal animals.

The role of computed tomography in blunt abdominal trauma in children.

This study was performed in order to test the hypothesis that abdominal computed tomography (CT) can assist in the decision to perform laparotomy in children following blunt trauma to the abdomen. Three hundred forty children with blunt abdominal trauma underwent evaluation with CT. Abdominal injuries were detected in 84 children (25%). These included: 75 injuries to solid viscera in 60 patients (30 splenic, 29 hepatic, 13 renal, and three pancreatic); four injuries to hollow viscera (three small bowel transections, and one rupture of the urinary bladder); and 23 skeletal injuries (21 fractures of the pelvis, and two lumbar spine subluxations). Injury to solid viscera was categorized as minor in 32 (43%), moderate in 18 (24%), or severe in 25 (33%) according to an assessment of the percentage of parenchyma involved. Hemoperitoneum was detected in 42 patients, and characterized as small in 18 (43%), moderate in nine (21%), and large in 15 (36%). CT was useful in establishing the location and extent of injuries, and in detecting the presence of blood or air in the peritoneal cavity. However, the extent of injury to solid viscera detected on CT did not correlate with the need for laparotomy. Of 46 moderate to severe anatomic injuries of the liver, spleen or kidney, only five (9%) required surgical intervention because of persistent bleeding or infection. Although laparotomy occurred more frequently in the presence of a large hemoperitoneum, only 6/24 (25%) with moderate to large hemoperitoneum required surgical exploration. This analysis confirms the usefulness of CT for detection of location and extent of injury in pediatric blunt abdominal trauma.(ABSTRACT TRUNCATED AT 250 WORDS)

Hematuria. A marker of abdominal injury in children after blunt trauma.

The clinical significance of hematuria after blunt trauma was studied in 378 consecutive children evaluated by computed tomography (CT) of the abdomen. Clinical and demographic data, as well as indications for CT (such as hematuria, abdominal tenderness, distention, contusions, and abrasions) were recorded prospectively at the time of CT examination. Hematuria was present in 256 children (68%). Of these, 168 (66%) had microscopic blood (greater than or equal to 10 RBC/HPF), 52 (20%) had a positive dip-stick (less than 10 RBC/HPF), and 36 (14%) had gross hematuria. Both the presence and increasing amount of blood in the urine were associated with significantly higher risk for abdominal injury, multiple organ trauma, and renal injury. Yet when asymptomatic hematuria was the only indication for CT examination, the risk of any abdominal injury was negligible (0 of 41 patients). The presence and severity of hematuria can be useful markers of underlying abdominal injury only in association with other suggestive clinical signs and symptoms. Asymptomatic hematuria is a low-yield indication for abdominal CT in children with blunt abdominal trauma.

Hepatic and splenic injury in children: role of CT in the decision for laparotomy.

Clinical and radiographic records of 274 children who were examined with abdominal computed tomography (CT) after blunt abdominal trauma were retrospectively evaluated to test the hypothesis that CT can assist in decisions to perform laparotomy in children with hepatic or splenic injury. CT demonstrated parenchymal injuries in 36 patients (13%) or 20 livers and 21 spleens. Injury to these organs was categorized as minor (39%), moderate (39%), and severe (21%) according to an assessment of the percentage of parenchymal involvement. Hemoperitoneum was detected in 27 of 36 patients (75%). One of 13 (4.7%) with a moderate to large splenic injury underwent splenorrhaphy because of persistent bleeding. One of 12 (5%) with a moderate to large hepatic injury required late operative intervention due to a large necrotic segment. Both children had a large amount of peritoneal fluid. Two of 16 patients (13%) with moderate to large hemoperitoneum required surgery for liver or splenic injury. The decision for laparotomy should not be based on the extent of injury as shown at CT but on the physiologic condition of the child.

Prenatal alcohol exposure: effects on acoustic startle and prepulse inhibition.

The present study evaluated the effects of prenatal exposure to alcohol on the acoustic startle reflex and prepulse inhibition in rats. Pregnant rats consumed an average of 12.36 g/kg/day of ethanol in a saccharin solution which served as their sole fluid source throughout gestation. Their offspring were found to be developmentally delayed on tests of physical maturation, but were not consistently impaired on tests of neuroreflexive development when compared to pair-fed and ad lib control groups. With development, subjects in the ethanol exposed group exhibited enhanced reactivity to an acoustic startle stimulus, which was evident at 35 but not at 21 days of age. In contrast, general activity levels were similar for all groups at 35 days of age, and there was no apparent disruption of the inhibitory effects of a prepulse stimulus. These results provide evidence that in utero exposure to alcohol may result in age dependent hyperreactivity, with no obvious disruption of normal prepulse inhibition or general activity levels.

A comparative evaluation of rare earth screen-film systems. Free-response operating characteristic analysis and anatomic criteria analysis.

Diagnostic accuracy was evaluated in a signal detection experiment that used low-contrast acute lesions in a living dog model. At the high levels of certainty normally used by radiologists, rare earth screen-film systems provided accuracy comparable to that of a reference calcium tungstate screen-film system. Additionally subjective image quality evaluation for a given imaging task (clinical pediatric anterior-posterior chest films) based on visualization of anatomic landmarks and physical parameters has been conducted for several rare earth and one calcium tungstate screen-film system. The correspondence of subjective physical ranking with physical and psychophysical measurements was investigated. Evaluating the visualization of anatomic parameters can provide a clear and objective distinction among systems with comparable physical and psychophysical properties.

A comparative evaluation of rare-earth screen-film systems. System speed, contrast, sensitometry, RMS noise, square-wave response function, and contrast-dose-detail analysis.

We evaluated the physical characteristics and contrast-dose-detail performance of 11 rare-earth and three calcium tungstate screen-film systems. Measurements included system speed, contrast, sensitometry, RMS noise, square-wave response function, and contrast-dose-detail analysis. The major differences in physical characteristics among systems were system speed and RMS noise. Square-wave response differences were more subtle. For contrast-dose-detail analysis, the rare-earth screen-film systems and the calcium tungstate system responses were significant over a limited subject contrast range as a function of detail diameter. Relative dose efficiency in the noise-limited region is a function of the properties of the screen only and is independent of the film.