Analysis of leucocytes and lymphocyte subsets in cats with naturally-occurring cryptococcosis but differing feline immunodeficiency virus status

Although cryptococcosis is a well-characterised disease of cats, the factors predisposing individuals to infection are unknown. As an indication of the immune status of an individual, lymphocyte subsets can be analysed. Reference ranges for feline lymphocyte subsets (Pan T+, CD4+, CD8+ and B cells) were established using a rapid whole blood technique and flow cytometry. There were no effects of age or sex on lymphocyte subset values. The numbers of circulating leucocytes and lymphocyte subsets were determined in FIV-positive and FIV-negative cats with cryptococcosis and compared with a group of healthy control cats. There were only minor differences in the numbers of lymphocyte subsets among the subgroups of cats examined in the study and the predisposition to cryptococcosis in cats could not be explained by deficiencies in lymphocyte subsets. There was a tendency for FIV-negative cats with cryptococcosis to have reduced numbers of circulating CD4+ cells and lower CD4:CD8 ratios compared with normal cats, although the interpretation of this finding was complicated by the wide reference range for normal cats. The extent to which this is the cause of the fungal infection was not determined. The only difference in leucocyte or lymphocytes subset values between FIV-negative cats with cryptococcosis and FIV-positive cats with cryptococcosis was that the CD4+ percentage was lower in the FIV-positive cats. The absolute CD4+ count was similar however, in FIV-positive and FIV-negative cryptococcosis cases. On the basis of this and other available information, the categorisation of cryptococcosis as a disease defining the AIDS phase of FIV infection may be incorrect.

Pharmacokinetics of fluconazole in cats after intravenous and oral administration

Fluconazole (100 mg) was administered to six adult cats as an intravenous infusion over 30 minutes, and the same cats received 100 mg of the drug orally 16 weeks later. The cats were bled repeatedly through an indwelling jugular catheter, the plasma fluconazole concentrations were assayed by high performance liquid chromatography, and the concentration-time data were subjected to a non-compartmental pharmacokinetic analysis. The mean (SD) intravenous half-life (13.8 [2.6] hours) was similar to that observed after oral dosing (12.4 [3.0] hours). The plasma clearances (intravenous 0.9 [0.1], oral 0.9 [0.2] ml min-1 kg-1) and the volumes of distribution at steady state (intravenous 1.1 [0.1], oral 1.0 [0.1] litre kg-1) were also similar after the two routes of dosing. The peak plasma concentration was reached 2.6 hours after oral dosing and the drug was completely bioavailable (1.09 [0.05]). On the basis of this single dose study, the administration of 50 mg fluconazole every eight hours to a 4 kg cat should produce average steady state plasma fluconazole concentrations of approximately 33 mg litre-1.

Vascular factors in diabetic neuropathy

Despite considerable research we still do not have a comprehensive explanation for the pathogenesis of diabetic neuropathy. Although chronic hyperglycaemia is almost certainly involved, it is not known whether the primary pathology is metabolic, microvascular, or an interaction between the two. Hyperglycaemia-induced polyol pathway hyperactivity associated with nerve sorbitol accumulation and myo-inositol depletion may play a part in the genesis of diabetic neuropathy. The case for microvascular disease in diabetic neuropathy is now strong. Fibre loss in human sural nerve is multifocal, suggesting ischaemia. The degree of vessel disease has been related to the severity of neuropathy. People with chronic obstructive pulmonary disease develop the so called "hypoxic neuropathy" in which similar microvascular changes occur as in diabetic neuropathy. In rats with experimental diabetic neuropathy nerve blood flow is reduced and oxygen supplementation or vasodilator treatment improved the deterioration in conduction velocity and nerve blood flow. Similarly, in human diabetic neuropathy, there is impaired nerve blood flow, epineurial arterio-venous shunting and a reduction in sural nerve oxygen tension. At what stage during the development of nerve damage these changes occur is yet to be determined.

Congenital portosystemic shunts in Maltese and Australian cattle dogs

Congenital portosystemic shunts were definitively diagnosed in 62 dogs over a period of 15 years. Maltese and Australian Cattle Dogs were significantly overrepresented, accounting for 14 and 13 cases, respectively. Maltese invariably had a single extrahepatic shunt derived from the left gastric or gastrosplenic vein, whereas Cattle Dogs usually had large intrahepatic shunts involving the right liver lobes. The clinical syndromes resulting from anomalous portosystemic communications were indistinguishable in the 2 breeds. Fasting blood ammonia concentration was elevated in 20 of 22 dogs tested, providing a minimally invasive and effective means of diagnosis. Complete or partial shunt attenuation was performed successfully in all 9 Maltese and in 2 of 6 Cattle Dogs in which it was attempted.

Flecainide: its value and danger

Flecainide is an important addition to the therapeutic armamentarium because it is a potent agent for the treatment of paroxysmal supraventricular tachycardia in patients without structural heart disease. Flecainide also may be useful in patients with debilitating nonsustained ventricular arrhythmias in the absence of structural heart disease. It is rarely useful in the management of life-threatening sustained ventricular arrhythmias.

Immunological profile in congenital heart disease

Fifty children with established congenital heart disease (CHD) were surveyed for the immune profile. Ventricular septal defect (VSD) was the commonest lesion (56%) followed by Tetralogy of Fallot (ToF; 16%), atrial septal defect (ASD; 8%), patent ductus arteriosus (PDA; 4%), transposition of great arteries (TGA; 4%), aortic stenosis (AS; 4%), and pulmonic stenosis (PS), tricuspid atresia (TA), single ventricle with pulmonic stenosis (SV with PS) and dextrocardia with ToF (2% each). Immunoglobulins (IgG, IgA and IgM) were estimated. IgG and IgA levels were significantly reduced in all children with congenital heart disease, whereas IgM levels were increased in cyanotic but unaffected in the acyanotic group. Complement C3 and C4 levels were reduced in all, more so in cyanotics. T-helper cells were decreased and T-suppressor cells were increased in all groups with congenital heart disease as compared to controls. B-cell percentage was increased in cyanotics but not affected in the acyanotics.

Cross-cultural beliefs about "depression"

This study set out to compare native Britons' and Asian-Britons' (from the Indian sub-continent) beliefs about the causes and cures of depression. In all 152 females took part, half of whom were middle-aged and half young. The results indicated that middle-aged Asian migrants significantly differed from the middle-aged British and young Asian samples in their beliefs about depression and anti-depressive behaviour. They also scored significantly higher than the middle-aged British women on a Western measure of psychiatric morbidity, yet they did not report depression in themselves or others. The young Asian sample, on the other hand, appear to have adopted a perception of depression that is similar to that of their British peers. It seems that the perception of the causes and symptoms of depression and appropriate anti-depressive behaviour is mediated by cultural values and beliefs that the individual has been exposed to in their formative years, which subsequently affects their tendency to recognise, report and seek help for depression. The results are discussed in terms of the literature on the 'new cross-cultural psychiatry'.

Use of a modified open patch-graft technique and valvulectomy for correction of severe pulmonic stenosis in dogs: eight consecutive cases

A modified open patch-graft technique was used to correct congenital pulmonic stenosis in 8 dogs. Pulmonary valve dysplasia was moderate to severe in all cases, based upon clinical and echocardiographic criteria, and 3 dogs were in right-sided congestive heart failure at the time of surgery. Seven of the 8 dogs survived the surgery. One surviving dog displayed cerebral cortical dysfunction, the remaining 6 had no detectable neurological sequelae. Right ventricular failure was alleviated in all 7 surviving dogs, but right ventricular dilatation persisted post-operatively. Pulmonary valvulectomy and open patch-grafting provides an effective means of alleviating signs of congestive heart failure caused by pulmonary valve dysplasia, even in the presence of severe infundibular hypertrophy and dynamic outflow obstruction.

Treatment of feline hyperthyroidism using orally administered radioiodine: a study of 40 consecutive cases

Forty cats with hyperthyroidism were treated using 200 to 300 (typically 250) MBq [corrected] of orally administered 131I. Thirty-six cases (90%) were successfully treated, as assessed by resolution of clinical signs and reduction in plasma thyroxine concentrations to normal or reduced values after treatment. Although higher doses of 131I appear to be required when the radioisotope is administered orally rather than intravenously, a less stressful administration procedure and greater availability of therapy capsules offer useful advantages for treating thyrotoxic cats.

Epidermoid cyst in association with subcutaneous meningioma

A 17-year-old female presented with a non-tender, firm and fixed swelling in the right frontal region. Skull x-rays revealed soft tissue shadow and mild hyperostosis of the underlying frontal bone. Histopathological examination after excision showed it to be a meningioma with an epidermoid cyst.

A new technique for surgery of the caudal vena cava in dogs using partial venous inflow occlusion

The haemodynamic and metabolic effects of caudal vena cava occlusion were evaluated in six normal anaesthetised dogs. Each animal underwent a single eight minute episode of caudal vena cava occlusion. The procedure was well tolerated by all the dogs. Systolic arterial pressure was reduced by 62 +/- 5 per cent and the heart rate increased by 11 +/- 3 per cent. There was rapid haemodynamic recovery after the release of occlusion, all cardiovascular parameters returning to normal spontaneously within five minutes. Caudal vena cava occlusion is therefore safe for periods of up to eight minutes in normal dogs. This technique allows repair of caudal vena caval lesions without necessitating systemic heparinisation and the use of cavoatrial conduits.

Total venous inflow occlusion in the normothermic dog: a study of haemodynamic, metabolic and neurological consequences

The acute haemodynamic and metabolic repercussions of total venous inflow occlusion were evaluated in six normal dogs, each of which underwent two four minute occlusions and one eight minute occlusion at normothermia. A further three dogs underwent a single eight minute period of occlusion and were allowed to recover from anaesthesia. Total venous inflow occlusion was well tolerated by all animals. They remained in sinus rhythm at the completion of occlusion, and unassisted haemodynamic recovery occurred rapidly. Recovery was quicker after four minutes than after eight minutes. There was no clinically detectable neurological impairment in three dogs which were allowed to recover.

Cryptococcosis in cats: clinical and mycological assessment of 29 cases and evaluation of treatment using orally administered fluconazole

Twenty-nine cats with naturally occurring cryptococcosis were evaluated prior to commencing oral fluconazole therapy (25-100 mg every 12 h). Affected cats ranged from 2 to 15 years-of-age. Male cats (19; 66%) and Siamese cats (5; 21%) appeared to be over-represented in comparison to the hospital's cat population. Mycotic rhinitis was observed in 24 (83%) of the cases, although nasal cavity involvement was subtle in four animals. Disease of the skin and subcutaneous tissues was present in 15 cases (52%) and amongst these the nasal plane (seven cats) and bridge of the nose (seven cats) were most commonly involved. Primary infection of the central nervous system was not encountered, although one cat developed meningoencephalitis and optic neuritis as a sequel to longstanding nasal cavity disease. Antibodies against the feline immunodeficiency virus (FIV) were detected in eight cats (28%), and these cats tended to have advanced and/or disseminated disease. There was a tendency for cats to develop cryptococcosis during the Australian summer. Organisms were cultured from 27 cases. Cryptococcus neoformans var. neoformans was isolated from 21 cats, while C. neoformans var. gattii was identified in the remaining six. The response to oral fluconazole was excellent in this series, which included many cats with advanced, longstanding or disseminated disease. The fungal infection resolved in all but one advanced case which died after only 4 days of therapy. A dose of 50 mg per cat, given every 12 h, produced a consistently good response without side effects. Lower doses were effective in some cases, while 100 mg every 12 h was required to control the infection in one cat. Serum fluconazole levels obtained during chronic dosing (50 +/- 18 mg l-1, mean +/- SD; 50 mg per cat every 12 h) were highly variable (range 15-80 mg l-1). Concurrent FIV infection did not impart an unfavourable prognosis, although affected cats often required prolonged courses of therapy.