Optimal stent length and distal positioning of frozen elephant trunks deployed from the aortic zone 0 for type A acute aortic dissection

OBJECTIVES

To investigate the optimal stent length and distal positioning of frozen elephant trunks (FETs) in patients with type A acute aortic dissection (TAAD).

METHODS

Between October 2014 and April 2021, 191 patients (FET-150 group: 37 patients; stent length, 150 mm; 66.3 ± 12.6 years and FET-non-150 group: 154 patients; 60, 90, or 120 mm; 64.1 ± 12.5 years) underwent total arch repair with FETs for TAAD using the "zone 0 arch repair" strategy. In the FET-150 group, the proximal stent end was positioned at the innominate artery origin of the arch. In the FET-non-150 group, the distal stent end was to be positioned just proximal to the aortic valve level using transesophageal echocardiography. The proximal end of the non-stented FET part was sutured to an arch graft together with the aortic wall at 1 to 2 cm proximal to the innominate artery origin.

RESULTS

Distal stent ends were positioned at the thoracic vertebrae (Th) 4-5, 6-7, 8-9, and 10 levels in 0 (0%), 12 (32.4%), 25 (67.6%), and 0 (0%) patients, respectively, in the FET-150 group, and in 6 (3.9%), 98 (63.6%), 49 (31.8%), and 1 (0.7%), respectively, in the FET-non-150 group. No between-group difference in postoperative mortality was noted. The incidence of postoperative residual distal malperfusion and new-onset spinal cord ischemia in the FET-150 versus FET-non-150 groups were 2.7% versus 6.5% (P = .62) and 0% versus 1.9% (P = 1.00), respectively.

CONCLUSIONS

FET positioning with the distal stent end at around Th 8 can reduce residual distal malperfusion when a FET with a 150-mm stent is deployed from the aortic zone 0 in patients with TAAD undergoing total arch repair.

Aortic remodeling, reintervention, and survival after zone 0 arch repair with frozen elephant trunks for acute type A aortic dissection: Midterm results

Objectives

To investigate the midterm results after zone 0 arch repair with frozen elephant trunks for acute type A aortic dissection.

Methods

Between October 2014 and April 2021, 196 patients underwent zone 0 arch repair with frozen elephant trunks for acute type A aortic dissection. The true lumen area, aortic lumen area, and false lumen status were assessed at four aortic levels, the proximal and distal descending thoracic aorta (level A and level B, respectively), celiac artery branching (level C), and terminal aorta (level D). Aortic remodeling (postoperative area as a percentage of the preoperative area) was classified into 3 groups, positive (true lumen area ≥120% with aortic lumen <120% or true lumen area ≥80% with aortic lumen <80%), minimal (80% ≤ true lumen area and aortic lumen area <120%), and negative remodeling (all other changes).

Results

In-hospital mortality was 13 (6.6%) patients. The overall survival rate was 85.1% at 5 years. The freedom from distal aortic reintervention was 89.9% at 5 years. The prevalence of completely thrombosed or obliterated false lumen at 2 years was 96.8% at level A, 88.4% at level B, 47.2% at level C, and 27.6% at level D. The prevalence of positive aortic remodeling at 2 years was 84.7% at level A, 75.0% at level B, 29.2% at level C, and 16.7% at level D.

Conclusions

Zone 0 arch repair with frozen elephant trunks for acute type A aortic dissection can avoid invasive aortic arch resection and facilitate aortic remodeling of the descending thoracic aorta. The FET effect on aortic remodeling is limited at the aortic level below the FET stent end.

Enhanced strategy against mediastinitis with thoracic vascular graft infection: A combination of hydro-debridement with pulsed lavage and negative pressure wound therapies

BACKGROUND

We investigated the effects of hydrodebridement with pulsed lavage (HDPL) and negative pressure (NP) wound therapies, instead of excising the prosthetic graft, in patients with postoperative thoracic vascular graft infection (TVGI).

METHODS

Between 2020 and 2021, five TVGI patients aged 49.6 ± 19.4 years old underwent a combined therapy of HDPL and NP. The patients underwent a two-step procedure (first step: re-sternotomy and HDPL; second step: NP) every 3 or 4 days. After negative tissue culture, the patients underwent omentum flap wrapping and skin closure.

RESULTS

No hospital death was observed. The time to skin closure was 10.8 ± 3.4 days. The time to the day in which bacteria were not cultured was 3.5 ± 2.4 days. No recurrent infections occurred for 241 ± 186 postoperative days.

CONCLUSION

Our strategy for TVGI patients may contribute to (1) sufficient infection control, (2) physical rehabilitation, and (3) less invasiveness for high-risk patients.

Subvalvular tissue mimicking valve detachment-like pathology by vertical aneurysm in Takayasu's arteritis

A 74-year-old woman with Takayasu's arteritis previously underwent aortic valve replacement at 59 years old. She was initially diagnosed with aortic valve stenosis and valve detachment. Moreover, preoperative computed tomography revealed ∼40 mm distance between the coronary artery ostium and the prosthetic valve (PV) and an aneurysm at the sinus of Valsalva. A Bentall procedure was subsequently performed. Intraoperative findings revealed no detachment of the PV. Following PV removal, the subvalvular tissue was noted to protrude into the left ventricular outflow tract. Subsequently, it was revealed that the tissue could have interfered with the PV; however, the PV appeared to have been detached considering the imaging findings.

Risk factors for spinal cord ischemia in frozen elephant trunk–induced upper spinal cord ischemia in patients with combination of degenerative arch aneurysms and peripheral artery diseases: a possible mechanism

Background

Degenerative aortic arch aneurysms are known to develop through a pathological process of arterial atherosclerosis, which could be accompanied by peripheral artery diseases and resultant development of intrapelvic collateral arteries to the ischemic lower limbs. The aim of this study was to investigate the relationship between peripheral collateral circulation and postoperative paraplegia after total arch repair with a frozen elephant trunk in patients with degenerative aortic arch aneurysms and peripheral artery diseases.

Methods

Between October 2014 and March 2020, 27 patients (20 men; 69.8 ± 7.7 years old) underwent total arch repair with a frozen elephant trunk. Two of the 27 patients developed paraplegia postoperatively. The patients were divided into two groups, spinal cord ischemia (SCI) group (2 patients) and no-SCI group (25 patients). The aortic shagginess score, arterial calcification (subclavian artery; hypogastric artery) score, and the number of hypogastric artery branches, assessed using preoperative contrast-enhanced computed tomography images, were compared between the two groups.

Results

The ankle brachial artery pressure index (i.e., lower side value each patient) was lower in the SCI group than that in the no-SCI group (0.64, 0.71, and 1.09±0.07, respectively). There was no difference between the two groups in the arterial calcification scores or the aortic shagginess score. The number of hypogastric artery branches was greater in the SCI group than in the no-SCI group (66, 66, and 30.7±7.5, respectively).

Conclusions

Enhanced collateral circulation to the ischemic lower limbs in patients with combination of degenerative aortic arch aneurysms and peripheral artery diseases may be involved in paraplegia the upper thoracic spinal cord injury after total arch repair with a frozen elephant trunk.

Endovascular rescue for malpositioned frozen elephant trunk into the false lumen

We describe a case of frozen elephant trunk deployment unintentionally malpositioned into the false lumen. An 83-year-old man underwent total arch repair with a frozen elephant trunk for type A acute aortic dissection complicated by mesenteric malperfusion. However, intraoperative transesophageal echocardiography showed expansion of the false lumen in the descending aorta, suggesting a malpositioned frozen elephant trunk into the false lumen. Endovascular fenestration of the dissecting flap and subsequent endograft deployment from the inside of the malpositioned frozen elephant trunk graft to the true lumen of the descending aorta was successfully performed under intravascular ultrasound guidance.

Right coronary ostium occlusion by aortic valve tumor during systole

Here, we present a case of acute myocardial infarction caused by an aortic valve tumor. Electrocardiography (ECG)-gated four-dimensional computed tomography revealed obstruction of the right coronary ostium by a mobile mass during systole. To ensure an accurate diagnosis of angina in patients without significant coronary artery disease, ECG-gated four-dimensional computed tomography is useful because it can simultaneously visualize the coronary ostium and arteries, aortic valve leaflets, and mass.

Surgical treatment for accidentally discovered pseudoaneurysm of the mitral-aortic intervalvular fibrosa with bicuspid aortic valve, ascending aortic aneurysm, and myocardial ischemia: a case report

Background

Pseudoaneurysm of the mitral-aortic intervalvular fibrosa (P-MAIVF) is a rare complication of infective endocarditis and aortic valve replacement. Ruptured P-MAIVF and angina due to compression of the coronary arteries are severe complications of this condition.

Case presentation

We report a case of P-MAIVF that was diagnosed accidentally during a routine checkup. The patient was asymptomatic; however, she had a systolic murmur. She had a history of infective endocarditis, which was treated conservatively without open-heart surgery. In addition, she was diagnosed with aortic valve stenosis, aortic valve regurgitation, bicuspid aortic valve, right coronary artery stenosis, and an ascending aortic aneurysm. She was treated with surgery, which involved patch closure of P-MAIVF with aortic valve replacement, coronary artery bypass grafting, and ascending aorta replacement. After the operation, echocardiography showed no leakage from the P-MAIVF.

Conclusions

It is necessary to have knowledge of P-MAIVF. Following up cases of infective endocarditis and post-aortic valve replacement using echocardiography is important for both, diagnosing P-MAIVF and preventing serious complications such rupture and angina.

Calcified Aortic Wall Removal for Dysphagia Aortica Caused by Chronic Traumatic Aortic Pseudoaneurysm

In this study, we report a case of a 45-year-old man with dysphagia aortica secondary to chronic traumatic aortic pseudoaneurysm of the aortic isthmus. He had been involved in a motor vehicle accident 27 years earlier. Computed tomography demonstrated a severely calcified aortic pseudoaneurysm of the aortic isthmus that compressed the esophagus extrinsically. An invasive surgical procedure involving a graft replacement and removal of the calcified aortic wall released the esophageal compression and completely improved the patient's symptoms. To the best of our knowledge, a case of dysphagia aortica caused by calcified pseudoaneurysm has never been reported.

[Traction-assisted Negative Pressure Wound Therapy for Pediatric Poststernotomy Mediastinitis:Report of Two Cases]

We herein report two cases of pediatric poststernotomy mediastinitis treated by traction-assisted negative pressure wound therapy (NPWT) with Zip Surgical Skin Closure (Zip), which is a non-invasive skin closure device. We used this device with NPWT in cases of pediatric poststernotomy mediastinitis to stabilize the sternum and reduce the natural retractive forces of the skin. The patients were two boys (two and three months old), with an onset of infection at 13 and eight postoperative days, respectively. The culture examination detected methicillin-susceptible Staphylococcus aureus in both cases. Traction-assisted NPWT with Zip was performed at-75 mmHg for 16 and 33 days, and the wounds healed completely. In conclusion, this modification was successfully applied to treat pediatric poststernotomy mediastinitis and may help reduce the duration of treatment.

Direct Abdominal Aortic Access for Thoracic Endovascular Aortic Repair in a Patient with Severe Aortic and Arterial Calcification

Aortic and arterial calcification is a complication of advanced atherosclerosis and is a critical intraoperative issue that can reduce the ability to achieve safe and adequate access for stent graft introduction. Different vascular access sites are used to deliver stent grafts when a standard transfemoral or iliac access is not feasible. We report a challenging case of a direct transabdominal aortic thoracic endovascular aortic repair for a thoracic aortic aneurysm complicated with severe aortic and arterial calcification, in which the noncalcified area of the infrarenal abdominal aorta was extremely limited. This may be a reasonable access site, especially for patients with severe aortic and arterial calcification.

[Thoracic Endovascular Repair for Chronic Aortic Dissection with Aberrant Origin of the Left Vertebral Artery;Report of a Case]

We herein report a case of thoracic endovascular aortic repair( TEVAR) for chronic aortic dissection with an aberrant left vertebral artery( LVA) originating from the aortic arch. A 51-year-old man with a medical history of Stanford type B acute aortic dissection 2 years ago was transferred to our institution for the treatment of an aortic expansion. Computed tomography showed a large entry just distal to the takeoff of the left subclavian artery and a dilated dissected thoracic aorta. A left cervical incision over the anterior border of the sternocleidomastoid was made, and the LVA was identified. The proximal LVA was ligated and anastomosed to the left common carotid artery in an end-to-side fashion. After completion of the carotid-subclavian bypass, TEVAR was performed in the usual fashion. The postoperative course was uneventful without stroke or spinal cord injury. At the 1-year follow-up, the false lumen had shrunk and the LVA remained patent.

Total arch repair with frozen elephant trunk using the “zone 0 arch repair” strategy for type A acute aortic dissection

OBJECTIVE

The aim of this study was to investigate the effect of frozen elephant trunk deployment from the zone 0 aorta to the descending aorta on early and midterm postoperative results in patients with acute type A aortic dissection.

METHODS

Between October 2014 and April 2018, 108 patients underwent a combined strategy of frozen elephant trunk deployment, ascending aortic replacement, and arch vessel reconstruction ("zone 0 arch repair" strategy) for acute type A aortic dissection (excluding DeBakey type II). Of the 108 patients, 32 (29.6%) had primary tears of the aortic arch or descending aorta.

RESULTS

The 30-day mortality rate was 2.8% (3 patients), and in-hospital mortality rate was 6.5% (7 patients). New-onset permanent neurologic dysfunction and spinal cord injury occurred in 3.7% and 0% of patients, respectively. Five of the 101 survivors underwent thoracic endovascular aortic repair during hospitalization (2 for rapid false lumen enlargement; 3 for true lumen stenosis). The overall survival was 89.8%, 88.1%, and 88.1% at 1, 2, and 3 years, respectively. The cumulative incidence of distal aortic reintervention was 5.8%, 9.1%, and 9.1% at 1, 2, and 3 years, respectively. Two patients underwent thoracic endovascular aortic repair for distal aortic enlargement after discharge.

CONCLUSIONS

The use of the "zone 0 arch repair" strategy can eliminate the need for invasive aortic arch resection. It also eliminates the false lumen and produces satisfactory early and midterm postoperative results. Therefore, it can be an alternative to hemiarch and total arch replacements, which are based on a conventional "tear-oriented resection" strategy.

Cardiac lesions in dairy cows with idiopathic atrial fibrillation

Histopathological examination of the heart, particularly the right atrium including the sinoatrial (SA) node, was carried out in 9 Holstein dairy cows with idiopathic atrial fibrillation (AF; AF group) and 12 healthy cows of the same breed (control group) in order to establish the correlation between idiopath

Pathologic and electrocardiographic findings in sudden cardiac death in racehorses

Five racehorses in apparently normal condition succumbed to sudden cardiac death (SCD) during or shortly after intensive training exercise. Cardiopathologic examination was performed. In 1 of the 5 horses, the use of an electrocardiogram (ECG) recording taken continuously for 440 sec enabled us to analyze some of the arrhythmias in the terminal event of SCD. The ECG tracing exhibited the R-on-T phenomenon following a pair of ventricular premature contractions (VPCs). The phenomenon rapidly degenerated into ventricular fibrillation, which led to cardiac arrest. In all 5 horses cardiopathologic examination revealed the following lesions: (i) foci of myocardial fibrosis in the right atrium located close to the sinoatrial (SA) node, (ii) fibrotic and/or fibroplastic changes in the upper portion of the interventricular septum, including the atrioventricular (AV) conduction system, and (iii) arterio- and arteriolosclerosis of the SA and AV node vessels. Pathogenetically, the process by which the focal lesions of myocardial ischemia secondary to vascular sclerosis progressed into fibrosis and/or fibroplasia could play a major role in the genesis of arrhythmias. Presumably the fibrotic and/or fibroplastic changes in the area of the AV bundle and its bundle branches are closely related to the onset of fatal ventricular arrhythmias such as VPCs, deteriorating into ventricular fibrillation. SCD in training and racing Thoroughbred horses appears to be due to arrhythmia.

Epithelioid haemangioendothelioma of the lung in a dog

Epithelioid haemangioendothelioma of the lung was found in a 9-year-old female dog. The tumour occurred bilaterally in the form of multiple, discrete, small nodular lesions with a similar histological appearance. The lesions were characterized by a hypocellular sclerotic core surrounded by a more cellular peripheral zone, from which the tumour tissue extended into the adjacent alveolar spaces and bronchioles in a micropolypoid manner, filling their lumina. In addition, invasion of the pulmonary vessels was frequently observed within, around, and at a distance from the nodular neoplastic lesions. Most of the tumour cells had abundant eosinophilic cytoplasm, large, round or oval nuclei, and occasional intracytoplasmic vacuoles containing red blood cells. By means of immunolabelling, factor VIII-related antigen, a marker for endothelial cells, was detected within the cytoplasm of a small proportion (< 5%) of the tumour cells. This appears to be the first report of such a tumour in an animal other than man.

Transmural myocardial infarction caused by thromboembolism associated with mitral insufficiency in a dog

A 10-year-old dog, which had been treated for mitral insufficiency, died suddenly. Transmural myocardial infarction secondary to thromboembolic occlusion of the subsinuosal interventricular branch of the left circumflex artery was noted in the posterior lower half of the left ventricular wall, involving the interventricular septum and a part of right ventricular wall. The mitral valve leaflets were markedly thickened (valvular endocardiosis). These were a patchy area of jet lesion and several mural thrombi on the left-atrial endocardium. The embolus in the subsinuosal interventricular branch was composed of mostly platelets and fibrin, showing the same histologic features as those of the mural thrombi on the left-atrial endocardium. From these findings, it was concluded that dislodgement of part of the mural thrombi on the left-atrial endocardium caused thromboembolism of the subsinuosal interventricular branch.

Effects of Ca2+ channel antagonists on striatal dopamine and DOPA release, studied by in vivo microdialysis

1. To elucidate the mechanisms regulating the release of striatal dopamine and its precursor, 3,4-dihydroxyphenylalanine (DOPA), we determined the effects of various Ca2+ channel antagonists, an N-type Ca2+ channel antagonist, omega-conotoxin GVIA, a P-type Ca2+ channel antagonist, omega-agatoxin IVA, and a Q-type Ca2+ channel antagonist, omega-conotoxin MVIIC, on the basal and Ca2+- and K+-evoked release of striatal dopamine and DOPA, by use of in vivo microdialysis. 2. Omega-conotoxin GVIA strongly inhibited striatal basal dopamine release (IC50 = 0.48 nM), whereas this toxin only weakly modulated basal striatal DOPA release (IC50 = 9.55 nM). Neither omega-agatoxin IVA nor omega-conotoxin MVIIC affected the basal striatal release of dopamine and DOPA. 3. Omega-conotoxin GVIA strongly inhibited Ca2+-evoked striatal dopamine release (IC50 = 0.40 nM), whereas Ca2+-evoked striatal DOPA release only was weakly modulated (IC50 = 10.51 nM). Neither omega-agatoxin IVA nor omega-conotoxin MVIIC affected the Ca2+-evoked release of striatal dopamine and DOPA. 4. Both omega-agatoxin IVA and omega-conotoxin MVIIC inhibited the K+-evoked release of striatal dopamine (IC50 of omega-agatoxin IVA = 2.65 nM; IC50 of omega-conotoxin MVIIC = 12.54 nM) and DOPA (IC50 of omega-agatoxin IVA = 0.15 nM; IC50 of omega-conotoxin MVIIC = 3.05 nM), whereas omega-conotoxin GVIA had no effect on the K+-evoked release of striatal dopamine and DOPA. 5. An increase in the extracellular Ca2+ and K+ concentrations (Ca2+- and K+-evoked stimulation) did not affect tyrosine hydroxylase activity in vivo. 6. These findings suggest that striatal DOPA release is neurotransmitter-like and that, unlike the mechanisms of striatal dopaminergic transmission, this striatal DOPA transmission is at least partly regulated by voltage-sensitive Ca2+ channels.

Fatal rupture of the brachiocephalic artery in a dog

A case of arterial rupture that caused sudden death in a 3-year-old dog is presented. Rupture of the brachiocephalic artery was located just distal to the origin of the left common carotid artery. Histological examination of the vessel wall revealed necrosis of the media.

Effects of adenosine receptor subtypes on hippocampal extracellular serotonin level and serotonin reuptake activity

To clarify the effects of adenosine receptor subtypes (A1, A2, and A3) on hippocampal serotoninergic function, hippocampal extracellular serotonin (5-HT) levels were determined by in vivo microdialysis in freely moving rats under various conditions. Both adenosine and an adenosine A1 receptor agonist, 2-chloro-N6-cyclopentyladenosine, decreased extracellular 5-HT levels, whereas an adenosine A1 receptor antagonist, 8-cyclopentyl-1,3-dimethylxanthine (CPT), and caffeine increased these levels. A selective A2A receptor agonist (CGS-21680), an adenosine A2 receptor agonist (PD-125944), an adenosine A2 receptor antagonist, 3,7-dimethyl-1-propargylxanthine (DMPX), and an adenosine A3 receptor agonist, N6-2-(4-aminophenyl)ethyladenosine (APNEA), did not affect extracellular 5-HT levels. When the adenosine A1 receptor was blocked by CPT, the hippocampal extracellular 5-HT level was increased by adenosine, CGS-21680, and PD-125944, and decreased by caffeine, DMPX, and APNEA. When both adenosine A1 and A2 receptors were blocked by CPT and DMPX, the extracellular 5-HT level was decreased by adenosine, caffeine, and APNEA. The hippocampal extracellular 5-HT level was not affected by administration of APNEA alone, but was decreased by this agent when the adenosine A1 receptor was blocked, irrespective of whether the adenosine A2 receptor was functional. These inhibitory effects of adenosine, caffeine, and APNEA on extracellular 5-HT levels, during both adenosine A1 and A2 receptor blockade, were inhibited by selective 5-HT reuptake inhibitors. These results indicate that the stimulatory effects of the adenosine A2 receptor and the inhibitory effects of the A3 receptor on hippocampal extracellular 5-HT levels are masked by the inhibitory effects of the adenosine A1 receptor.

Biphasic effects of carbamazepine on the dopaminergic system in rat striatum and hippocampus

To clarify the effects of carbamazepine (CBZ) on dopamine (DA) release and their metabolism, the extracellular and total levels of DA, its metabolites (DOPAC and HVA) and precursor, 3,4-dihydroxyphenylalanine (DOPA) in the striatum and hippocampus were studied. DA re-uptake and DOPA accumulation in the striatum and hippocampus, and monoamine oxidase (MAO) activities were also determined. After acute and chronic administrations of CBZ, the plasma concentration of CBZ associated with therapeutic activity increased the extracellular and total levels of all substances determined, whereas supratherapeutic concentration of CBZ decreased extracellular and total levels of all substances. Neither therapeutic nor supratherapeutic concentrations of CBZ affected MAO-A nor -B activities, nor DA re-uptake. DOPA accumulation caused by NSD1015 was inhibited by therapeutic and supratherapeutic concentrations of CBZ. These results suggest that a therapeutic concentration of CBZ enhances DA turnover, whereas a supratherapeutic concentration of CBZ inhibits DA turnover. These effects of CBZ on dopaminergic systems may be, at least partially, involved in the mechanisms of action of CBZ.

Effects of non-toxic and toxic concentrations of phenytoin on monoamines levels in rat brain

To clarify the mechanisms of the antiepileptic activity of phenytoin (PHI), the effects of PHT on extracellular and total levels of monoamines (dopamine and serotonin), in rat striatum and hippocampus were studied. The plasma concentrations of PHT associated with therapeutic activity did not affect striatal and hippocampal extracellular levels of monoamines, whereas supratherapeutic concentrations of PHT decreased striatal and hippocampal extracellular levels of monoamines, in a concentration dependent manner. Toxic concentrations of PHT produced generalized seizures 'paradoxical intoxication' and an initial drastic decrease in striatal and hippocampal extracellular levels of monoamines before seizure onset, whereas the extracellular monoamines levels increased after seizures. In addition, the therapeutic concentrations of PHT did not affect monoamine turnover, whereas supratherapeutic concentrations of PHT inhibited monoamine turnover. These results suggest that monoaminergic transmission may not be involved in the antiepileptic mechanism of action of PHT, and that dysfunction of monoaminergic transmission can produce generalized tonic-clonic convulsions. Thus, the present study suggests that 'Paradoxical Intoxication' induced by toxic concentrations of PHT, at least partially, can be mediated by hypo-monoaminergic function in the brain.

Prognosis and clinical features of intractable epilepsy: a prospective study

Of the epileptic patients who were treated for > or = 5 years until the end of 1990 and had more than four seizures in 1990, 63 patients had been treated without interruption until the end of 1995. We analyzed their clinical courses from 1990 to 1995 prospectively. More than half the subjects were diagnosed with temporal lobe epilepsy. Twenty cases had presumed etiology, and 32 had neuropsychiatric complications. Of the subjects whose seizures were not controlled with conventional antiepileptic drugs (AED), 11 cases demonstrated significant improvement when new AED; that is, lamotrigine, vigabatrin, clobazam, topiramate, tiagabine or CGP33101 were added. However, 10 patients did not respond to new AED. Presumed etiology, neuropsychiatric complications, multiple epileptic foci in EEG and abnormalities on head CT or MRI were characteristics of the patients whose seizures were resistant to new AED.

Hypertrophic cardiomyopathy in a common wombat (Vombatus ursinus)

A case of hypertrophic cardiomyopathy (HCM) in a common wombat (Vombatus ursinus) is described. At necropsy, the heart showed symmetrical ventricular hypertrophy, a narrow left ventricular cavity, and dilatation of the left atrium. Microscopical findings in the ventricular myocardium included a strikingly disordered arrangement of cardiac muscle cells, in which adjacent cells were aligned perpendicularly and obliquely to each other, interstitial myocardial fibrosis, and arteriosclerosis of small intramural coronary arteries (fibromuscular hyperplasia). The changes, which were widespread in both ventricles, resembled those of HCM in man and other animals.

Cardio-histopathological observations on aborted equine fetuses infected with equid herpesvirus 1 (EHV-1)

Twenty-five aborted equine fetuses infected with equid herpesvirus 1 (EHV-1) were examined cardio-histopathologically. The main changes in the heart consisted of interstitial myocarditis and intramyocardial vascular lesions accompanied by degeneration and necrosis of the cardiac myocytes. Vascular pathology of intramyocardial small arteries and arterioles was characterized by endothelial cell necrosis and fibrinoid changes in the media. Eosinophilic intranuclear inclusion bodies characteristic of herpesvirus infection were detected in the myocardial cells and macrophages within and around the inflammatory lesions and in the endothelial cells and medial smooth muscle cells of the damaged vessels. This observation, taken in conjunction with the fact that EHV-1 antigens were detected immunohistochemically in some myocardial and endothelial cells, provides morphological evidence in support of the viral aetiology of the cardiac lesions.

Determination of the effects of caffeine and carbamazepine on striatal dopamine release by in vivo microdialysis

The effects of carbamazepine and caffeine on adenosine receptor subtypes were determined using in vivo microdialysis in an attempt to elucidate their different psychotropic mechanisms of action. Adenosine and a selective adenosine A1 receptor agonist decreased the striatal extracellular dopamine level, whereas caffeine, carbamazepine and a selective adenosine A1 receptor antagonist increased it, but neither an adenosine A2 receptor agonist nor an antagonist affected it. Under conditions of adenosine A1 receptor blockade, adenosine, carbamazepine and a selective adenosine A2 receptor agonist increased the striatal extracellular dopamine level, whereas caffeine and a selective adenosine A2 receptor antagonist decreased it. These results suggest that adenosine A1 receptor stimulation reduces the striatal extracellular dopamine level, and that adenosine A2 receptor stimulation under conditions of adenosine A1 receptor blockade increases it. Therefore, caffeine is an antagonist of both adenosine A1 and A2 receptor subtypes, and carbamazepine is an adenosine A1 receptor antagonist as well as an adenosine A2 receptor agonist. These properties support the hypothesis that the central actions of both carbamazepine and caffeine result from effects on both adenosine A1 and A2 receptors.

Electrocardiographic observation on spontaneously occurring arrhythmias in chickens

In order to clarify the spontaneous occurrence of arrhythmias in chickens, electrocardiograms using standard bipolar limb leads were recorded for 461 chickens of 7 breeds, including 3 pure breeds: Rhode Island Red (RIR, n = 125), Japanese Game (JG, n = 101), and White Leghorn (WL, n = 52); and 4 crossbreeds of RIR: the first filial generation (F1) obtained by mating RIR with JG (RIR x JG, n = 44), the backcross obtained by mating the Fl of RIR x JG with the parental JG ((RIR x JG) x JG, n = 10), the F1 obtained by mating RIR with WL (RIR x WL, n = 73), and the F1 obtained by mating RIR with the commercial hybrid chicken, Dekalb Amber Link (DAL)(RIR x DAL, n = 56). Nine types of arrhythmias were observed in 107 chickens (23.2%, 107/461): 66 had sinus arrhythmia, 19 had atrial premature contraction, 9 had ventricular preexcitation syndrome, 7 had ventricular premature contraction, 2 had second-degree atrioventricular block. 1 had atrial fibrillation, I had aberrant ventricular conduction. I had intraventricular conduction disturbance, and 1 had ventricular electrical alternans. Except for sinus arrhythmia, the incidence of other arrhythmias in RIR was significantly high, compared with that in pure breeds other than RIR (p < 0.001) and that in crossbreeds of RIR (p < 0.01). Arrhythmias other than ventricular premature contraction and sinus arrhythmia will be the first to be described as spontaneously occurring arrhythmias in chicken. Although the reason for both the highest incidence of sinus arrhythmia in WL and the predominance of other arrhythmias in RIR were obscure, the present results suggest the possibility of using chickens, especially RIR which shows a high incidence of arrhythmias, as a relevant animal for studying arrhythmias.

Two necropsy cases of hypertrophic cardiomyopathy in Holstein cattle

Two cases of hypertrophic cardiomyopathy in Holstein dairy cows are presented. At necropsy, the hearts revealed proportionate hypertrophy of the entire ventricles. The cut surface showed relatively large areas of myocardial scarring scattered throughout the ventricular walls including the septum. Microscopic examination revealed marked disorganization of cardiac muscle cells, intramural coronary arteries with thickened walls and narrowed lumina, and pronounced myocardial fibrosis. These features resemble those of hypertrophic cardiomyopathy in humans, suggesting the presence of a similar primary myocardial disease in cattle.

Phenotypic expressions of type I, III, IV, V, and VI collagens in patients with diabetic nephropathy: immunohistochemical comparison between HD and non-HD patients

Molecular organization of extracellular matrix (ECM) in the kidney may change as impairment of renal function progresses. The present immunohistochemical study of the kidney was designed to compare localization of type I, III, IV, V, and VI collagens between "Group A" (13 patients on maintenance hemodialysis due to diabetic nephropathy) and "Group B" (13 patients with diabetic nephropathy and massive proteinuria whose serum creatinine levels were 1.3 +/- 0.5 mg/dl, mean +/- SD). Nodular scleroses that were commonly observed both in Group A (87.8 +/- 10.1%) and B (80.5 +/- 17.0%) were stained in a very similar way with antibodies against collagen types IV, V, and VI. On the contrary, thickened Bowman's capsules that were observed exclusively in Group A (80.7 +/- 10.4% in Group A versus 5.7 +/- 6.2% in Group B) were stained intensely with antibodies against collagen types I and III. Normal and expanded peritubular interstitium from every group was stained with all of the above antibodies in an identical manner. Taken together, these results indicated a close relationship between severe impairment of residual renal function and a high incidence of thickened Bowman's capsule rich in type I and III collagens.

Pathology and epidemiology of canine distemper in raccoon dogs (Nyctereutes procyonoides)

From September to December 1991, a large number of free-ranging raccoon dogs (Nyctereutes procyonoides) died from a highly contagious disease in the vicinity of Tokyo. Eighteen seriously ill or dead animals were submitted for necropsy. The pathological findings resembled those in a masked palm civet (Paguma larvata) found infected with canine distemper virus (CDV) in the same area in late August 1991. The most striking features were pneumonia and gastroenteritis. Microscopical lesions consisted of cytoplasmic and intranuclear eosinophilic inclusion bodies in various organs and tissues, bronchiolointerstitial pneumonia, non-suppurative demyelinating encephalitis, lymphocytic depletion in various lymphoid tissues and catarrhal or necrotizing gastroenteritis. CDV-specific antigens, demonstrated immunohistochemically in the epithelial tissues, central nervous system and lymphoid tissues, corresponded with the presence of the eosinophilic inclusion bodies in sections of the same lesions stained with haematoxylin and eosin. Ultrastructurally, both cytoplasmic and intranuclear inclusion bodies were observed to be composed of aggregates of viral nucleocapsids. The study provided clear evidence that CDV was the cause of the disease. It is possible that the masked palm civet introduced the infection into the raccoon dog population.

Electrocardiographic features and incidence of atrial fibrillation in apparently healthy dairy cows

Two hundred and eighty-five apparently healthy Holstein dairy cows were evaluated serially for atrial fibrillation (AF) over an 18-month period. AF was noted in 7 cows with an incidence of 2.5%. No particular disease conditions were noted in any case at the time of onset of AF and thereafter. In Cases 1, 2 and 3, arrhythmia developed 30 to 40 days postpartum and persisted thereafter. In Case 4, AF developed 28 days postpartum and lasted for 2 days before spontaneous conversion to normal sinus rhythm. In Cases 5 and 6, AF occurred 2 days after the animals ceased lactation and disappeared spontaneously within a few days. In Case 7, AF developed just before calving and reverted to normal sinus rhythm spontaneously on the 2nd day postpartum. Thus, 3 animals (Cases 1, 2 and 3) exhibited established AF whereas the remaining 4 animals (Cases 4, 5, 6 and 7) demonstrated paroxysmal AF, suggesting that different causative factors may be involved in the genesis of AF in the 7 cases presented here. The genesis of the AF in these cases which had no underlying disease conditions may be interpreted as an increased load imposed on the heart, increased sympathetic tone, or increased vagal tone.

Cardiopathological observation on a case of persistent ventricular tachycardia in a pony mare

A 20-year-old pony mare with persistent ventricular tachycardia (VT) was examined cardiopathologically. At necropsy, the heart was enlarged and rounded with both ventricular dilatation. In a longitudinal section of the ventricular septum, a large grayish white patchy lesion (5 x 25 mm) was detected in the relatively higher portion. Microscopically, the lesion was extensive myocardial fibrosis located in the vicinity of the proximal part of the left bundle branch. Partially the fibrotic lesion was in contact with the branch. Such a lesion might play an important role in creating a suitable background for the development of VT via automaticity or reentry mechanism.

Canine distemper virus infection in a masked palm civet (Paguma larvata)

A free-living masked palm civet (Paguma larvata) died after exhibiting signs of canine distemper (CD). The microscopic lesions consisted of cytoplasmic and intranuclear eosinophilic inclusion bodies, bronchointerstitial pneumonia, non-purulent encephalitis accompanied by demyelination and lymphocytic depletion in various lymphoid tissues. CD virus-specific antigens were demonstrated immunohistochemically in intracellular eosinophilic inclusions, which were ultrastructurally confirmed to be viral nucleocapsids. From these findings, the present case was diagnosed as CD virus infection in a masked palm civet.

Histologic features of the carotid artery trifurcation in thoroughbreds

The common, external, and internal carotid and occipital arteries were examined histologically at the trifurcation of the common carotid arteries in 13 Thoroughbred foals (0 to 30 days old) and 64 Thoroughbred adults (2 to 4 years old). Calcification in the media of the common carotid and external carotid arteries was observed in 3 of the 13 foals and in 30 of the 64 adult horses. Calcification resembled that seen in Mönckeberg's arteriosclerosis in human beings, the cause of which is unknown.

Morphological changes of the aorta and pulmonary artery in thoroughbred racehorses

The aorta and extrapulmonary artery were examined pathologically in 33 thoroughbred racehorses ranging in age from 1 to 5 years. Many of the great vessels of these horses exhibited degenerative or sclerotic changes in the media with neither lipidosis nor deposits of cholesterol. The severe lesions were predominantly observed at the bifurcation of the pulmonary artery. The severity of the lesions in both the aorta and pulmonary artery appeared to be associated with the racing career of the racehorse rather than with increasing age. Histopathogenetically, the medial changes in the great vessels were probably initiated by ischaemia and/or oedema in their walls due to pathological disturbances of the vasa vasorum and their vasomotor nerves. Whether hypervitaminosis D plays a role in the condition in racehorses needs to be determined by further study.