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Biomedical subjects

B R Jones

Publications and source records attributed to B R Jones.

At least 55 records · Page 3Linked to original sources
PubMed1997

A survey for torovirus in New Zealand cats with protruding nictitating membranes.

Faecal samples from 51 cats were examined by negative stain electron microscopy to investigate a possible association between the syndrome of bilateral protrusion of the nictitating membranes and torovirus infection. Although toroviruses were not observed in any sample, other viruses or virus-like particles were observed in faeces from one of 15 cats with the syndrome, six of 21 cats which had experienced prior episodes of the syndrome and four of 15 healthy control cats. The findings of this study do not support the hypothesis that the syndrome is associated with torovirus infection.

Journal Article↗
PubMed1997

Elucidating the risk factors of feline lower urinary tract disease.

A questionnaire-based case-control study investigating the association of a range of host-related, owner-related and environmental risk factors with feline lower urinary tract disease was conducted in New Zealand over a 2-year period from 1991 to 1993. The study was subsequently extended in two ways, to examine the influence of the use of litter trays and to correlate weather records with the appearance of the disease in one particular region of the country. A range of statistical techniques was employed to analyse the data, including univariate odds ratio and chi-squared calculations, time series analysis, Poisson regression and conditional and unconditional logistic regression. Variables that were positively associated with lower urinary tract disease included low activity levels, the use of a litter tray coupled with restriction indoors, a high number of rainfall days in the month preceding the appearance of clinical signs, stress factors such as moving house within the last 3 months or the presence of more than one cat in the household, and a diet high in dry cat food. There was some indication that high levels of fluid consumption reduced the effect of a diet high in dry cat food. Other variables that appeared to have some protective effects included a routine visit to the veterinarian in the last 12 months and the use of alternative food sources such as rodents and birds.

Journal Article↗
PubMed1997

Protozoal encephalomyelitis of dogs involving Neospora caninum and Toxoplasma gondii in New Zealand.

In a retrospective study of 15 cases of encephalomyelitis in dogs, three cases of Neospora caninum and two cases of Toxoplasma gondii infection were identified using immunohistochemical staining of central nervous system sections. All cases of neosporosis showed ataxia and progressive hind limb paralysis due to multifocal non-suppurative meningoencephalomyelitis which was most severe in the spinal cord and base of the brain stem. Neospora tissue cysts could not be distinguished morphologically from those of T. gondii using light microscopy, but electron microscopy confirmed their characteristic features. Although Neospora abortion in cattle has only recently been recognised in New Zealand, this study has shown that neosporosis has been present in dogs since at least 1972.

Journal Article↗
PubMed1997

Visual field constriction as a cause of blindness or visual impairment.

Reported are the results of a study of onchocerciasis in communities mesoendemic for savanna onchocerciasis in Kaduna State, northern Nigeria. The study involved 6831 individuals aged > or = 5 years who underwent an extensive screening examination for visual function including Friedmann field analysis. A total of 185 (2.7%) were bilaterally blind by acuity and an additional 28 (0.4%) were blind by visual field constriction. Also 118 (1.7%) individuals were visually impaired by acuity criteria. No criteria for visual impairment by field constriction have been established, and we therefore investigated three potential criteria. As a result, a further 60 (0.9%) individuals were identified with significant visual impairment due to field loss by the various definitions. Small islands of remaining peripheral field occurred in 50 individuals, while 40 individuals had marked reduction of binocular visual field below the horizontal meridian. Concentric visual field constriction to < 20 degrees was found in seven individuals. The WHO definition of blindness currently includes visual field damage criteria for blindness but not for visual impairment. Visual field loss is recognized as a major disability. We hope that these findings stimulate international discussion leading to the development of satisfactory definitions for visual impairment by visual field constriction.

Adolescent↗
PubMed1997

Impact of annual dosing with ivermectin on progression of onchocercal visual field loss.

Reported are the results of a randomized, double-masked, placebo-controlled trial of annual ivermectin dosing in 34 rural communities, Kaduna State, northern Nigeria, where guinea savanna onchocerciasis is mesoendemic. A total of 939 individuals underwent Friedmann field analysis at the first examination and saw at least 19 spots in at least one eye. Of these, 636 (68%) completed a subsequent Friedmann field analysis 2-3 years later. The adjusted incidence rate ratio for the ivermectin group versus the placebo group was 0.64 (95% confidence interval (CI): 0.42-0.98). There was some evidence that the impact of ivermectin was greatest among those who had received one dose of ivermectin. The majority of the deteriorations occurred in eyes that gave evidence of optic atrophy at the first examination. An analysis restricted to individuals with optic atrophy at baseline indicated a reduction of 45% in the incidence of visual field deterioration in the ivermectin group (95% CI: 8-67%). Previous findings have shown that ivermectin has an impact on the incidence of optic atrophy. Our results indicate, for the first time, that ivermectin has a substantial impact on the progression of visual field loss among those with pre-existing optic atrophy.

Adolescent↗
PubMed1996

Technological advances in implantable cardioverter-defibrillators before the year 2000 and beyond.

The implantable cardioverter-defibrillator (ICD) has evolved rapidly since its clinical introduction; product life cycles have been exceedingly short. This swift transition from early shock-only devices to small, programmable, tiered-therapy systems has been driven by 2 major factors: minimally invasive implant procedures and technological innovation. Yet, while many new ICD systems have been introduced recently, even more advanced products are on the horizon before the year 2000 and beyond. In general, devices will be smaller and smarter. Certainly, ICD volume will be further reduced without detrimentally affecting longevity. Endocardial lead systems will become smaller and more versatile. Rhythm discrimination algorithms will become more effective. New adaptive-rate pacing systems that limit the maximum paced rate based on hemodynamic indices will become features of tachyarrhythmia products. Pacing schemes for prevention of supraventricular tachyarrhythmias and improvement of hemodynamic function in patients with congestive heart failure will likely be introduced for clinical evaluation.

Cardiac Pacing, Artificial↗
PubMed1996

A mutation in the lipoprotein lipase gene is the molecular basis of chylomicronemia in a colony of domestic cats.

Members of a domestic cat colony with chylomicronemia share many phenotypic features with human lipoprotein lipase (LPL) deficiency. Biochemical analysis reveals that these cats do have defective LPL catalytic activity and have a clinical phenotype very similar to human LPL deficiency. To determine the molecular basis underlying this biochemical phenotype, we have cloned the normal and affected cat LPL cDNAs and shown that the affected cat has a nucleotide change resulting in a substitution of arginine for glycine at residue 412 in exon 8. In vitro mutagenesis and expression studies, in addition to segregation analysis, have shown that this DNA change is the cause of LPL deficiency in this cat colony. Reduced body mass, growth rates, and increased stillbirth rates are observed in cats homozygous for this mutation. These findings show that this LPL deficient cat can serve as an animal model of human LPL deficiency and will be useful for in vivo investigation of the relationship between triglyceride rich lipoproteins and atherogenic risk and for the assessment of new approaches for treatment of LPL deficiency, including gene therapy.

Amino Acid Sequence↗
PubMed1996

Neutropenia with a probable hereditary basis in Border Collies.

This paper documents a disease of Border Collies characterised by chronic neutropenia which probably resulted in recurrent bacterial infections manifesting as osteomyelitis and sometimes gastroenteritis. The neutropenia occurred despite hyperplasia of the myeloid cells in the bone marrow and a shift to the right in myeloid cell maturation. The underlying defect is currently unknown but may result from the inability of neutrophils to escape from the bone marrow into the peripheral circulation. Necrosis and new bone formation commonly involved the metaphyseal regions of long bones. Other findings included a fasting hypercholesterolaemia and the occasional presence of nucleated red blood cells in circulation, despite a non-regenerative anaemia. An autosomal recessive mode of inheritance is suspected. This condition has some features of a rare human disease called myelokathexis which is also believed to have in autosomal recessive mode of inheritance.

Journal Article↗
PubMed1996

Localised tetanus in two cats after ovariohysterectomy.

Localised tetanus was diagnosed in two cats 14 and 21 days after ovariohysterectomy by a left flank surgical approach. The diagnosis in each case was based on their history, clinical signs and diagnostic investigations which excluded other possible diagnoses. Both cats showed scoliosis of the lumbar spine and left hind limb spasticity. One cat's clinical signs were exacerbated after the administration of corticosteroids. One cat was treated with oral amoxycillin and diazepam, and the second cat received penicillin, tetanus antitoxin, methocarbarnol and diazepam. Both cats improved after treatment but recovery was prolonged and the spasticity did not resolve until 12 weeks after diagnosis in one cat. The second cat was lost to follow up after 8 weeks.

Journal Article↗
PubMed1996

Maintaining compliance to ivermectin in communities in two West African countries.

We have investigated various aspects related to managing wide-scale ivermectin distribution schemes within randomized controlled trials in communities where onchocerciasis is endemic. Multiple logistic regression analysis of determinants of compliance to five doses of ivermectin in 589 people in Sierra Leone showed independent significant associations with leopard skin depigmentation, the severity of side effects of treatment, fulfilling the exclusion criteria for treatment, and long-term residence in the community. These results are useful for tailoring health promotion messages in Sierra Leone, but the associations may differ in other West African societies. In Nigeria 1847 people were interviewed about various subjective responses, including itching. None of these showed clear improvement after three years of ivermectin treatment. Positive comments about treatment were generally non-specific and similar in the placebo and ivermectin groups. Negative comments were usually related to adverse reactions, especially itching and rash, and were more common after ivermectin. The lack of any benefit attributable to ivermectin that is discernible to its recipients may make it difficult to maintain the high compliance rates needed for long periods if mass dosing programmes are to have a lasting impact on onchocerciasis. In addition, no consistent effects of ivermectin were found by measuring visual acuity, height, weight or haematocrit in comparison with placebo. This may indicate that evidence of clinical impact is very slow to develop and is hard to measure using simple objective methods after only three doses of treatment. At present it seems that parasitological, entomological and detailed ophthalmological or dermatological methods are required to demonstrate the impact of ivermectin treatment in the medium-term.

Adolescent↗
PubMed1996

Human onchocerciasis in Nigeria: isotypic responses and antigen recognition in individuals with defined cutaneous pathology.

Antigen (Ag)-specific isotype responses to Onchocerca volvulus Ag (OvAg) were assessed by enzyme-linked immunosorbent assay and immunoblot in 123 residents of a mesoendemic area in northern Nigeria and 16 Nigerians from a nonendemic area. Individuals from an endemic area were divided into six groups on the basis of cutaneous onchocercal pathology: acute papular onchodermatitis (APOD), chronic papular onchodermatitis (CPOD), lichenified onchodermatitis (LOD), atrophy (ATR), depigmentation (DPM) and normal skin, high microfilarial load (NSHMF). Immunoglobulin (Ig)G1-4 levels were all significantly associated with residence in an endemic area after controlling for age and sex (all P values = 0.0001). Both IgG1 and IgG3 were significantly associated with onchocercal clinical category after controlling for age, sex, and microfilarial load (P = 0.0031 and 0.0035, respectively). The IgG1 and IgG3 responses were both highest in LOD and lowest in NSHMF and ATR, respectively. A significant inverse association was found between IgG1 levels and microfilarial load after controlling for age, sex, and clinical category (P = 0.0061). On immunoblotting, 20 (44.4%) of 45 individual onchocerciasis sera contained IgG4 antibodies against a band of 29-31 kD, which was not recognized by pooled sera from individuals with other filarial infections. There was heterogeneity of antigen recognition within each of the onchocercal clinical groups, which together with the small numbers examined by immunoblotting, limits interpretation. Nevertheless, some differences in patterns of antigen recognition were found between the onchocercal groups. The LOD group demonstrated prominent immunoreactivity in IgG1 and IgG3 while a general paucity of low molecular weight reactivity was seen with NSHMF in IgG1-3 subclasses, but there was no specific banding pattern that differentiated NSHMF from those with pathology. Comparison of microfilariae-positive (mf+) and mf- individuals with onchocercal skin disease revealed significantly higher levels of all IgG subclasses and higher overall scores on semiquantitative assessment of immunoblots for IgG1, IgG2, and IgG4 for mf+ individuals. Differing isotypic responses may play a role in the pathogenesis of the clinical spectrum of cutaneous onchocerciasis.

Adolescent↗
PubMed1996

Red-dot card test of the paracentral field as a screening test for optic nerve disease in onchocerciasis.

A new screening test for optic nerve pathology is described, consisting of a series of four red targets presented at an angle of 12 degrees in the paracentral field above and below the horizontal meridian. Nonperception and desaturation of the targets are recorded. Inter-observer variability studies found a kappa value = 0.8. A total of 6831 individuals aged > or = 5 years in communities that were mesoendemic for savanna onchocerciasis in Kaduna State, northern Nigeria, were screened using the test. Of the participants 22% were unable to complete the test; almost two-thirds of these (62%) were aged 5-8 years. After exclusion of those visually impaired or blind according to WHO criteria and those unable to complete the test, the test showed a sensitivity of 40% and a specificity of 98% for optic nerve disease when inability to visualize one or more targets was used as the definition of test failure. The sensitivity increased to 54% with a specificity of 96% when the criterion for failure included desaturation of one or more targets. These values compare favourably with those for other available screening methods. The test took 1-2 minutes to perform and was readily accepted by patients and nurses.

Child↗
PubMed1995

Hematopoietic cell transplantation in fetal lambs with ceroid-lipofuscinosis.

Hematopoietic cells from the liver of normal 45-48-day-old fetal lambs (Hb type AA) were transplanted intraperitoneally into 58-60-day-old recipient fetuses (Hb type BB). The recipient fetuses resulted from mating homozygous ceroid-lipofuscinosis affected males with heterozygous, phenotypically normal, females. The sex of the donor fetus was also recorded. At age 2 1/2 months the recipient lambs with ceroid-lipofuscinosis were diagnosed by histopathology of brain biopsies. Monitoring of blood and bone marrow cells showed that an average of 9% of blood cells in ceroid-lipofuscinosis affected recipients were of donor origin. No differences were evident in the clinical course of disease, brain weight, or histopathology of organs between transplanted and non-transplanted lambs with ceroid-lipofuscinosis. Under the conditions of this experiment, transplantation of fetal hematopoietic cells was not beneficial.

Animals↗
PubMed1995

A survey of anaesthetic equipment in veterinary practices in New Zealand.

Sixty-four anaesthetic machines and 89 breathing circuits were surveyed in New Zealand veterinary practices. Each machine and circuit was tested for correct function. Sixty-six percent of machines checked were 10 years or older and vaporiser out-of-circuit machines totalled 72% of machines surveyed. Twenty-five percent of the temperature compensated vaporisers had been serviced within the previous 1 year, 33% serviced between 1 and 10 years ago, while the remaining 42% had no service record or had not been serviced for over 10 years. Sixty-six percent of machines had some type of scavenging device. Nineteen percent of machines had a leak in the high pressure system. Thirty percent of the anaesthetic machine low pressure systems leaked and 76% of the patient breathing circuits leaked. Overall, 91% of all anaesthetic machines and breathing circuits showed malfunctions which could increase practice operating costs, increase the exposure of practice personnel to anaesthetic agents, and increase patient morbidity.

Journal Article↗
PubMed1995

The prevalence of feline immunodeficiency virus infection in hyperthyroid cats.

One hundred and thirty-four male and female hyperthyroid cats (mean age 11.9 years) were tested for the presence of feline immunodeficiency virus antibodies. Thirty-two (23.9%) were positive. The prevalence of feline immunodeficiency virus antibodies was greater in male cats (30.5%) than in female cats (17.2%). The prevalence of feline immunodeficiency virus infection in hyperthyroid cats is similar to the prevalence of feline immunodeficiency virus in the sick cat population and less than that of sick aged cats at the Massey University Clinic and Hospital. The findings of this survey do not support involvement of feline immunodeficiency virus in the pathogenesis of hyperthyroidism in the cat.

Journal Article↗
PubMed1995

Endocrine alopecia in a miniature poodle.

Hypothyroidism and concurrent sex hormone imbalance associated with alopecia was diagnosed in a 5 year-old entire male Miniature Poodle. The dog had a 3-year history of alopecia, seborrhoea and recurrent superficial pyoderma. Abnormal thyrotropin releasing hormone stimulation test results supported a diagnosis of hypothyroidism. Partial hair regrowth occurred after interstitial cell tumours, which were present in both testicles, were removed by castration. Complete hair regrowth, however, occurred only after thyroid hormone supplementation. This case highlighted difficulties which may be encountered when interpreting serum hormone concentrations and endocrine function tests.

Journal Article↗