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Biomedical subjects

R Malik

Publications and source records attributed to R Malik.

At least 109 records · Page 6Linked to original sources
PubMed1999

Asymptomatic carriage of Cryptococcus neoformans in the nasal cavity of the koala (Phascolarctos cinereus).

Over a 22-month period, sequential nasal and skin swabs were obtained from 52 healthy captive koalas (Phascolarctos cinereus) from the Sydney region. Cryptococcus neoformans was isolated in 17 koalas from 64 of 262 (24%) nasal swabs and from nine of 262 (3%) skin swabs. Prevalence of nasal colonization varied seasonally from 12% (3/25) to 38% (10/26). Cryptococcus neoformans var. gattii alone was cultured from 37, var. neoformans alone from 22 and both varieties from five nasal swabs. Of 33 koalas sampled on three or more occasions, organisms were isolated persistently from six, occasionally from eight and never from 19. Two koalas were persistently and heavily (>/=100 colonies/plate) colonized by C. neoformans var. gattii and two with var. neoformans. Isolation of C. neoformans var. gattii from the skin was low grade and sporadic. No koalas from which C. neoformans was persistently isolated showed clinical signs of cryptococcosis and all except one had a negative latex cryptococcal antigen test, therefore the nasal cavity was presumed to be colonized by, rather than infected with, C. neoformans. Preliminary observations of koalas from Coffs Harbour indicated a much higher prevalence of colonization by C. neoformans, suggesting that environmental factors influenced the extent of carriage by C. neoformans.

Animals↗
PubMed1999

Intestinal obstruction by trichobezoars in five cats.

Between 1997 and 1999, five domestic crossbred cats (four long haired, one short haired) presented with a palpable abdominal mass and were shown to have small intestinal trichobezoars at laparotomy or necropsy. Hair balls were associated with partial or complete intestinal obstruction and were situated in the proximal jejunum to distal ileum. In four cats obstructions were simple, while the remaining cat had a strangulating obstruction. Three of the cats were 10 years or older, and two were less than 4 years. In the three older cats abdominal neoplasia was suspected and investigations were delayed or declined in two of these cats because of a perceived poor prognosis. Predisposing factors identified in this series of cats included a long-hair coat, flea allergy dermatitis, inflammatory bowel disease and ingestion of non-digestible plant material. This report shows that the ingestion of hair is not always innocuous and that intestinal trichobezoars should be considered in the differential diagnoses of intestinal obstruction and intra-abdominal mass lesions, particularly in long-haired cats.

Animals↗
PubMed1999

Intra-abdominal cryptococcosis in two dogs.

Intra-abdominal cryptococcosis was diagnosed in two young dogs. The first, an entire male border collie, was presented with vomiting. An abdominal mass detected during physical examination proved to be cryptococcal mesenteric lymphadenitis on exploratory laparotomy. The second dog, a female neutered giant schnauzer, was presented with neurological signs suggestive of encephalopathy. Intestinal cryptococcal granulomas were detected in an extensive diagnostic investigation which included abdominal ultrasonography. The gastrointestinal tract was considered the most likely portal of entry for cryptococcal organisms in both cases. Both dogs were treated using surgery and multiagent antifungal chemotherapy. The first case succumbed despite therapy, while the second dog was treated successfully as gauged by return to clinical normality and a substantial decline in the cryptococcal antigen titre which continued to fall after cessation of treatment.

Abdomen↗
PubMed1999

Chronic pneumonia caused by Mycobacterium thermoresistibile in a cat.

Mycobacterium thermoresistibile was isolated in pure culture from ultrasound-guided pulmonary aspirates taken from a young cat with severe, chronic, pyogranulomatous pneumonia. Thoracic radiography and ultrasonography before therapy demonstrated severe diffuse alveolar disease. Twelve months combination therapy with doxycycline, rifampicin and clarithromycin resolved the infection. Thoracic radiographs taken at the completion of therapy showed multifocal pulmonary mineralisation. M thermoresistibile has been infrequently reported as a human or animal pathogen. This is the first reported pulmonary infection by M thermoresistibile in a cat and documents the successful treatment of the organism in a feline patient.

Animals↗
PubMed1999

Effect of acute haemorrhage on QRS amplitude of the lead II canine electrocardiogram.

OBJECTIVE: To examine the effect of acute haemorrhage on the QRS amplitude of the canine lead II surface electrocardiograph (ECG). DESIGN: Ten adult racing Greyhounds were tranquilised, anaesthetised, positioned in right lateral recumbency and connected to recording electrodes of an ECG unit. Baseline six-lead ECG traces were recorded, and further traces were obtained after one unit (460 mL) of blood, and then a second unit, were collected from the femoral artery. RESULTS: There was a consistent and progressive reduction in amplitude of the QRS complex in all leads during acute haemorrhage. QRS amplitude in lead II after removal of two units of blood averaged 74% of the baseline voltage, with individual values of 61 to 91% (P < 0.0001). There were even greater reductions in QRS amplitudes in lead aVL during haemorrhage. In three additional dogs, reductions in QRS voltages were shown to be accompanied by reductions in end-diastolic left ventricular internal dimensions measured echocardiographically. Furthermore, the effects of haemorrhage on the QRS amplitude and echocardiographic measurements were reversed when circulating blood volume was restored by re-infusion of blood removed previously. CONCLUSION: Acute haemorrhage corresponding to an approximately one-third reduction in blood volume caused a substantial reduction in QRS voltage of the surface ECG. It is postulated that this resulted from diminished ventricular distension as a consequence of reduced venous return. A similar mechanism may account for the small-amplitude ECG complexes associated with pericardial effusion, severe dehydration and hypovolaemia.

Acute Disease↗
PubMed1999

Polycystic kidney disease in bull terriers: an autosomal dominant inherited disorder.

The prevalence, mode of inheritance and urinalysis findings in Bull Terriers with polycystic kidney disease were assessed by screening 150 clinically normal dogs. The disorder was diagnosed in 39 dogs on the basis of renal ultrasound results and family history of the disease. In equivocal cases confirmation required gross and histopathological renal examination. Necropsy was performed on nine affected dogs and the kidneys from another five affected animals were also examined. Renal cysts were usually bilateral, occurred in cortex and medulla and varied from less than 1 mm to over 2.5 cm in diameter. Cysts were lined by epithelial cells of nephron origin. Abnormal urine sediment and proteinuria were common in affected dogs. The disease appears to be inherited in a highly penetrant autosomal dominant manner.

Animals↗
PubMed1999

Management of perianal fistulae in five dogs using azathioprine and metronidazole prior to surgery.

OBJECTIVE: To evaluate combination therapy with azathioprine and metronidazole in German Shepherd Dogs with perianal fistulae. DESIGN: Prospective study. PROCEDURE: Five dogs (31.5 to 36.0 kg) with perianal fistulae were treated with azathioprine (50 mg per dog orally every 24 h) and metronidazole (400 mg per dog orally every 24 h). Patients were re-evaluated at 2 week intervals by inspection, palpation, photographs of the perineal region and assessment of white blood cell counts where possible. Treatment was continued until improvement in lesions reached a plateau. Surgical excision of residual fistulae and anal sac remnants was then performed, with medical therapy continued for an additional 3 to 6 weeks. RESULT: Signs attributable to anal irritation were reduced or eliminated in all dogs within 2 weeks, although visible healing of lesions progressed more slowly. Ulcerated lesions reduced in surface area and depth, and some fistulae healed completely. Non-healing areas were usually associated with anal sac rupture or chronic fibrosis. Visible improvement typically reached a plateau 4 to 6 weeks after commencing treatment. Immunosuppressive therapy continued for 5 to 24 weeks before surgical intervention to remove anal sacs (four dogs) and/or residual fistulae (five dogs). All dogs remain disease free 7 to 10 months postoperatively. No important complications of treatment were encountered. CONCLUSION: Azathioprine with metronidazole effectively reduced perianal irritation, and the severity and extent of lesions prior to surgery. Treatment was economical even in large dogs and associated with few untoward sequelae. The combined use of immunosuppressive and antimicrobial therapy followed by surgery minimised potential morbidity associated with aggressive use of either medical of surgical treatment alone.

Administration, Oral↗
PubMed1999

Osteochondrodysplasia in Scottish Fold cats.

OBJECTIVE: To better characterise the bone and joint problems which can develop in Scottish Fold cats. DESIGN: Retrospective study of cases seen in five veterinary clinics and radiographic survey of cats in a cattery. RESULTS: Six Scottish Fold cats (four castrated males, two spayed females) aged between 5 months and 6 years were presented for signs of skeletal disease including lameness, reluctance to jump, a stiff stilted gait, short misshapen distal limbs, swelling of plantar tarsometatarsal regions and short thick inflexible tails. A further four cases (one male, three females, 15 months to 11 years) were identified by radiographic screening of a cattery. A diagnosis of osteochondrodysplasia was based on characteristic radiological findings including irregularity in the size and shape of tarsal, carpal, metatarsal and metacarpal bones, phalanges and caudal vertebrae, narrowed joint spaces, and progressive new bone formation around joints of distal limbs with diffuse osteopenia of adjacent bone. A plantar exostosis caudal to the calcaneus was present in advanced cases. In all nine cases where pedigree information was available, affected cats allegedly originated from the mating of a Scottish Fold to a cat with normal ears. The severity and time of onset of physical signs, and rate of progression and extent of radiographic abnormalities, varied from case to case. Limited histological observations suggested the underlying problem may be an osteochondrodysplasia, related to inadequate cartilage maturation. Clinical signs were ameliorated by administration of pentosan subcutaneously in two of three cats in which it was trailed, and one of these also benefited from an oral glycosaminoglycan preparation. CONCLUSIONS: Clinical and radiological findings were ascribed to defective maturation and function of cartilage, particularly in the distal limbs, ears and tail. As all Scottish Fold cats suffered from osteochondrodysplasia of some degree, the best solution would be to avoid using fold-eared cats for breeding and instead use Scottish shorthairs.

Animals↗
PubMed1999

Immunophenotypic and histological characterisation of 109 cases of feline lymphosarcoma.

OBJECTIVE: To determine and analyse the immunophenotype and histological appearance of naturally occurring cases of lymphosarcoma in Australian cats. DESIGN: A prospective multi-institutional study of naturally occurring feline lymphosarcoma. METHODS: One hundred and eighteen cats were referred for diagnosis and/or management of suspected lymphosarcoma. Tissue samples for histopathological analysis and immunophenotyping were collected as biopsies or at necropsy from 109 cases. Histological classification of the neoplasms followed the Working Formulation Classification System. Four multi-species cross-reactive antibodies were used to classify tumours as having a B or T cell phenotype. RESULTS: Seventy-six (70%) cases were B cell tumours and 28 (26%) were T cell tumours. The remaining 5 (4%) specimens failed to stain with the four antibodies. Histologically, 11 (10%) cases were classified as low-grade, 72 (66%) were medium-grade and 26 (24%) were high-grade tumours. There were no significant associations between age and either histological grade or immunophenotype. Mediastinal and leukaemic cases were significantly more likely to be T cell tumours (P < 0.001 and P < 0.001, respectively). CONCLUSIONS: In contrast to previously documented studies in the cat, the majority of cases of lymphosarcoma were of B cell phenotype and intermediate histological grade. Based on our data, the histological phenotype of lymphosarcoma is unlikely to predict immunotype, nor are cases of certain immunotypes likely to be of specific histological subtype. Considered in relation to previous reports, the findings suggest that epidemiological factors operating in these cats to produce lymphosarcoma may be different to those operating in North American and UK cat populations.

Animals↗
PubMed1999

Seasonal vitamin D status of Greyhounds in Sydney.

OBJECTIVES: To survey the vitamin D status of a population of Greyhounds in New South Wales, and to establish a reference range for plasma 25(OH)D. To investigate whether any seasonal fluctuation in vitamin D status is detectable in these animals. DESIGN: Vitamin D status was assessed in Greyhounds and crossbred dogs presented to the University of Sydney for teaching purposes over a 24 month period. PROCEDURES: Plasma 25(OH)D concentration was measured as an estimate of vitamin D status. Physical examination and plasma calcium concentration were used to verify the health of the animals, particularly with respect to metabolic bone disease. RESULTS: A plasma 25(OH)D concentration range of 10 to 76 nmol/L was found in healthy adult Greyhounds. There was no sex- or season-dependent variation in vitamin D status in Greyhounds. Concentrations in crossbred dogs did not differ significantly from those in Greyhounds. CONCLUSION: The reference range for plasma 25(OH)D concentration in Greyhound dogs is similar to that previously reported for humans. It would seem that healthy dogs in the Sydney region do not exhibit a seasonal fluctuation in their vitamin D status.

Animals↗
PubMed1999

Cytology and histopathology of canine leproid granuloma syndrome.

OBJECTIVE: To describe the histopathology of canine leproid granuloma syndrome. DESIGN: Histological examination of biopsy specimens taken from dogs with leproid granuloma syndrome. Biopsies were acquired from four veterinary pathology practices after initial examination showed acid-fast bacilli or lesions suggestive of a mycobacterial aetiology. Tissue from 30 cases formed part of a retrospective survey while a further 7 cases were obtained prospectively. PROCEDURE: Tissue samples were fixed in formalin and paraffin embedded. Sections were stained with haematoxylin and eosin and Ziehl-Neelsen stains. Slides were evaluated for the type of inflammatory response and the number of bacteria. In a few cases smears made from crush preparations and needle aspirates were stained with DiffQuik and acid-fast stains. RESULTS: The common cytological feature seen in DiffQuik stained smears was numerous, often spindle-shaped, macrophages with variable numbers of lymphocytes and plasma cells and lower numbers of neutrophils. Usually few to moderate numbers of medium length bacilli were detected within macrophages or extracellularly. Histologically, lesions were chiefly pyogranulomatous within the subcutis and dermis. Pyogranulomas were composed chiefly of epithelioid macrophages and neutrophils but plasma cells and small lymphocytes were scattered throughout the lesions in which giant cells were seen. Lesions were pyogranulomatous in 36 cases and granulomatous with small suppurative foci in one. The numbers of acid-fast bacilli present were very low to low in 22 cases, moderate in 6 and regionally numerous to numerous in 9. Bacteria were pleomorphic, ranging from long, slender filaments in parallel sheaves to short and variably-beaded bacilli or highly beaded to coccoid organisms. The morphology was more uniform in DiffQuik stained smears than in fixed tissue sections. CONCLUSION: The pathology of canine leproid granuloma syndrome is highly uniform and is suggestive of saprophytic mycobacterial involvement. The morphological diversity of acid-fast bacilli probably results from differences in staining characteristics rather than indicating different species of Mycobacterium. While approximately half of the cases had only few organisms present, the veterinary practitioner using a Romanovsky stain such as DiffQuik on aspirated material might expect to obtain a rapid diagnosis in many cases. This would allow differentiation of the syndrome from neoplastic and other diseases of the skin and direct appropriate treatment at the initial presentation.

Animals↗
PubMed1999

Surgical removal of an ependymoma from the third ventricle of a cat.

A 10-year-old spayed domestic shorthaired cat was presented for behavioural changes, signs suggestive of visual deficits and aimless circling. Neuro-ophthalmological examination suggested the cat had central blindness. CT scans following administration of iohexol demonstrated a contrast-enhancing mass in the vicinity of the third ventricle resulting in obstructive hydrocephalus. Following rostral tentorial craniotomy and incision through the cerebral cortex, the third ventricle was approached via the dilated left lateral ventricle. An ependymoma was seen through a dorsocaudolateral incision into the third ventricle, and removed by gentle manipulation and suction. The cat recovered unremarkably, regaining normal vision and behaviour.

Animals↗
PubMed1999

Presence of alpha and a mating types in environmental and clinical collections of Cryptococcus neoformans var. gattii strains from Australia.

Cryptococcus neoformans var. gattii lives in association with certain species of eucalyptus trees and is a causative agent of cryptococcosis. It exists as two mating types, MATalpha and MATa, which is determined by a single-locus, two-allele system. In the closely related C. neoformans var. neoformans, the alpha mating type has been found to outnumber its a counterpart by at least 30:1, but there have been very limited data on the proportions of each mating type in C. neoformans var. gattii. In the present study, specific PCR primers were designed to amplify two separate alpha-mating-type genes from C. neoformans var. gattii strains. These were used to survey for the presence of the two mating types in clinical and environmental collections of C. neoformans var. gattii strains from Australia. Sixty-eight of 69 clinical isolates produced both alpha mating type-specific bands and were assumed to be of the alpha mating type. The majority of environmental isolates were also of the alpha mating type, but the a mating type was located in two separate areas. In one area, the a mating type outnumbered the alpha mating type by 27:2, but in the second area, the ratio of the two mating types was close to the 50:50 ratio expected for sexual recombination.

Animals↗
PubMed1999

EWS-FLI1 and EWS-ERG gene fusions are associated with similar clinical phenotypes in Ewing's sarcoma.

PURPOSE: There are a variety of solid tumors in which alternative chromosomal translocations generate related fusion products. In alveolar rhabdomyosarcoma and synovial sarcoma, these variant fusions have been found to have major clinical significance. We investigated whether the two alternative gene fusion products, EWS-FLI1 and EWS-ERG, define different clinical subsets within the Ewing's sarcoma family of tumors. PATIENTS AND METHODS: We selected 30 cases of Ewing's sarcoma with the EWS-ERG gene fusion and 106 cases with the EWS-FLI1 fusion. Clinical data were obtained for each case and compared with the molecular diagnostic findings. RESULTS: There were no significant clinical differences observed between the two groups in age of diagnosis, sex, metastasis at diagnosis, primary site, event-free survival, or overall survival. CONCLUSION: Differences in the C-terminal partner in the Ewing's sarcoma family gene fusions are not associated with significant phenotypic differences.

Adolescent↗