Excitation Gap in the Normal State of Underdoped Bi2Sr2CaCu2O8+delta

Angle-resolved photoemission experiments reveal evidence of an energy gap in the normal state excitation spectrum of the cuprate superconductor Bi2Sr2CaCu2O8+delta. This gap exists only in underdoped samples and closes around the doping level at which the superconducting transition temperature Tc is a maximum. The momentum dependence and magnitude of the gap closely resemble those of the dx2-y2 gap observed in the superconducting state. This observation is consistent with results from several other experimental techniques, which also indicate the presence of a gap in the normal state. Some possible theoretical explanations for this effect are reviewed.     

Use of transesophageal atrial pacing to provide temporary chronotropic support in a dog undergoing permanent pacemaker implantation

A 14.5-kg, 13-year-old female spayed Cocker spaniel was evaluated because of episodic hind limb weakness. Results of examination were consistent with sick sinus syndrome with intermittent second-degree atrioventricular block. Transesophageal atrial pacing was successful in providing chronotropic support during permanent pacemaker implantation. Transesophageal atrial pacing appears to be a viable option for temporary atrial pacing in dogs with hemodynamically marked bradycardia without significant atrioventricular blockade.     

Echocardiographic evidence for myocardial failure induced by taurine deficiency in domestic cats.

Dietary taurine-deficiency is a cause of dilated cardiomyopathy (DCM) in cats. While the incidence of clinical cases of feline DCM has markedly decreased since the association between DCM and taurine-deficiency was first recognized, not all cats maintained on taurine-deficient diets develop DCM. The objective was to temporally evaluate left ventricular (LV) function using M-mode echocardiography in 23 cats maintained on a taurine-deficient diet; 20 time-matched, taurine-supplemented cats served as controls. The duration of feeding trials ranged from 6-15 months. No diminution of myocardial function was recorded in a small number of taurine-deficient cats whereas cardiac performance in some taurine-deficient cats diminished to levels characteristic of DCM. Of the taurine-deficient cats, 17 (74%) experienced a greater than 25% reduction in fractional shortening and 21 (91%) had a greater than 25% increase in LV end-systolic short-axis diameter. On average, LV end-systolic short-axis diameter increased by 70% and fractional shortening decreased by 37% in taurine-deficient cats. Mean velocity of circumferential fiber shortening was similarly reduced in taurine-deficient cats. The greatest rate of change in M-mode echocardiographic variables occurred during the first four months on the taurine-deficient diet. Dietary taurine deficiency leads to a spectrum of changes in myocardial function in domestic cats. While DCM is observed in some cats, decreased systolic pump function and increased LV end-systolic short-axis diameter are more consistent findings.     

Thrombolytic Therapy in Dogs and Cats

Objective: To review the thrombolytic agents most commonly used in humans, their mechanisms of action, potential uses, adverse effects, and reports of their use in dogs and cats.
Human data synthesis: Thrombolytic agents avaliable in human medicine include streptokinase, urokinase, tissueplasminogen activator (t-PA), single-chain urokinase plasma activator (scu-PA) and anisoylated plasminogen-strep-tokinase activator complex (APSAC). These agents were originally used for the management of proximal deep vein thrombosis and severe pulmonary embolism but more recently, use of these drugs has been extended to include the treatment of acute peripheral arterial disease, cerebrovascular disease (stroke) and acute coronary thrombosis. The most predictable side effect associated with the use of thrombolytic therapy is hemorrhage.
Veterinary data synthesis: Clinical experience with thrombolytic agents in small animals is limited to streptokinase and t-PA. It is possible, that as in humans, canine and feline patients with PTE and right ventricular dysfunction may benefit from thrombolytic therapy but there are no veterinary studies to support this theory to date. Successful use of streptokinase has been documented in a small number of canine patients with systemic thromboembolism. ⁶³ Thrombolytic therapy is relatively efficacious in cats with aortic thromboemboli but is associated with a high mortality rate. ^59,60,64 With regard to use of t-PA in veterinary medicine, the small number of animals treated with varying protocols makes it impossible to provide safe and effective dose recommendations at this time.
Conclusions: Future goals for thrombolytic therapy in veterinary medicine include determination of more specific clinical indications, as well as design of effective protocols that minimize mortality and morbidity.     

Enhancement of superoxide production in vitro by the diphenyl ether herbicide nitrofen

Light-dependent reduction of p-nitro blue tetrazolium chloride (NBT) and 2,6-dichlorophenol-indophenol (DCPIP) was stimulated by nitrofen (2,4-dichlorophenyl p-nitrophenyl ether) in the presence or absence of the photosensitizer riboflavin. Enhancement of NBT reduction occurred at a concentration as low as 17 μM nitrofen. Nitrofen had no effect on dark reduction of NBT by dithionite, ascorbate, or reduced phenazine methosulfate. NBT reduction proceeded in solution saturated with either air or nitrogen. Stimulation by nitrofen in the presence or absence of riboflavin also occurred independently of oxygen. Superoxide dismutase (superoxide:superoxide oxidoreductase; EC 1.15.1.1) inhibited light-dependent, aerobic reduction of NBT and DCPIP with and without riboflavin. The nitrogen-stimulated component was also eliminated. Thus, it appears nitrofen can effect reduction of NBT (and DCPIP) anaerobically by transferring electrons directly to NBT (and DCPIP) through an oxygen-independent mechanism or aerobically via superoxide radicals.     

Treatment of a well differentiated pulmonary adenocarcinoma in a cat by pneumonectomy and adjuvant mitoxantrone chemotherapy

Primary lung neoplasia is a rare condition of older cats. This report describes a case of left-sided pulmonary collapse, secondary to pulmonary adenocarcinoma in an 11-year-old cat. Left sided pneumonectomy was performed, and adjuvant chemotherapy with mitoxantrone (Novantrone; Lederle) was administered every 3 to 5 weeks, for 10 doses after surgery. Thirty-four months after surgery, the cat remains well and has no radiographic evidence of pulmonary metastasis.