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Biomedical subjects

N Bradford

Publications and source records attributed to N Bradford.

9 recordsLinked to original sources
PubMed2001

A cost-minimization analysis of the societal costs of realtime teledermatology compared with conventional care: results from a randomized controlled trial in New Zealand.

A randomized controlled trial was carried out to measure the societal costs of realtime teledermatology compared with those of conventional hospital care in New Zealand. Two rural health centres were linked to a specialist hospital via ISDN at 128 kbit/s. Over 10 months, 203 patients were referred for a specialist dermatological consultation and 26 were followed up, giving a total of 229 consultations. Fifty-four per cent were randomized to the teledermatology consultation and 46% to the conventional hospital consultation. A cost-minimization analysis was used to calculate the total costs of both types of dermatological consultation. The total cost of the 123 teledermatology consultations was NZ$34,346 and the total cost of the 106 conventional hospital consultations was NZ$30,081. The average societal cost of the teledermatology consultation was therefore NZ$279.23 compared with NZ$283.79 for the conventional hospital consultation. The marginal cost of seeing an additional patient was NZ$135 via teledermatology and NZ$284 via conventional hospital appointment. From a societal viewpoint, and assuming an equal outcome, teledermatology was a more cost-efficient use of resources than conventional hospital care.

Cost Savings↗
PubMed2000

Patient cost-benefits of realtime teledermatology--a comparison of data from Northern Ireland and New Zealand.

As part of a randomized controlled trial of the costs and benefits of realtime teledermatology in comparison with conventional face-to-face appointments, patients were asked to complete a questionnaire at the end of their consultation. One hundred and nine patients took part in an initial teledermatology consultation and 94 in a face-to-face consultation. The proportion of patients followed up by the dermatologist was almost the same after teledermatology (24%) as after a hospital appointment (26%) and for similar reasons. Two hundred and three questionnaires were completed after the first visit and a further 20 after subsequent visits. Patients seen by teledermatology at their own health centre travelled an average of 12 km, whereas those who attended a conventional clinic travelled an average of 271 km. The telemedicine group spent an average of 51 min attending the appointment compared with 4.3 h for those seen at the hospital. The results of the present study, as in a similar study conducted in Northern Ireland, show that the economic benefits of teledermatology favour the patient rather than the health-care system.

Computer Systems↗
PubMed1998

Influence of age on the response to Streptococcus pneumoniae vaccine in patients with recurrent infections and normal immunoglobulin concentrations.

BACKGROUND: A deficient antibody response to polysaccharide antigens is determined by measuring the response to the 23-valent pneumococcal polysaccharide vaccine. However, the diagnosis of this specific antibody deficiency is hampered by the lack of sufficient data and standardized testing of the response to pneumococcal polysaccharides. METHODS: All patients evaluated in our allergy/immunology clinic for recurrent respiratory infections between 1995 and 1997 without immunoglobulin, IgG subclass, or other known primary or secondary immunodeficiency were included in this analysis. IgG antipneumococcal serotypes 1, 3, 4, 6B, 9V, 14, 18C, 19F, and 23F were determined by a modified ELISA protocol. An adequate IgG antibody response to an individual serotype was arbitrarily defined as a postimmunization antibody titer of 1.3 microg/ml or greater or at least four times the baseline value. RESULTS: A total of 113 patients fulfilling the criteria for inclusion in this analysis were divided into five age groups. The geometric means for preimmunization and postimmunization pneumococcal antibody titers for all serotypes increased with age. For post-immunization antibody concentrations, there was a sharp increase in the specific antibody concentrations in adults in comparison with all pediatric age groups ranging in age from 7 months to 16 years. Similarly, the number of serotypes to which there was an adequate response also increased with age. CONCLUSION: We conclude that the definition of what constitutes an adequate response to pneumococcal immunization needs further definition. It is clear, however, that age has an important influence on the intensity of the response to most pneumococcal polysaccharides. Correlation studies between antibody concentrations in different IgG subclasses, functional studies, and protection studies against mucosal and invasive pneumococcal infections are in progress, and these should contribute to a refined definition of a normal response. The availability of a standardized method for the measurement of IgG antibodies against relevant pneumococcal serotypes is an important step toward this goal.

Adolescent↗
PubMed1998

Response to a heptavalent conjugate Streptococcus pneumoniae vaccine in children with recurrent infections who are unresponsive to the polysaccharide vaccine.

OBJECTIVE: To determine whether children with recurrent respiratory infections who failed to respond to the conventional polysaccharide vaccine would respond to a pneumococcal conjugate vaccine. METHODS: Children referred to our clinic for recurrent respiratory infections who had no known primary or secondary immunodeficiencies were immunized with a 23-valent pneumococcal polysaccharide vaccine. IgG antibodies to pneumococcal serotypes 1, 3, 4, 6B, 9V, 14, 18C, 19F and 23F were determined by enzyme-linked immunosorbent assay before and 4 to 6 weeks after immunization. An adequate IgG antibody response to an individual serotype was arbitrarily defined as a postimmunization antibody titer > or =1.3 microg/ml or at least 4 times the preimmunization value. Immunization with an experimental CRM197-heptavalent pneumococcal conjugate vaccine was offered to patients without an adequate response to 4 or more vaccine serotypes (nonresponders). Post-conjugate immunization antibody concentrations were measured 4 to 6 weeks later. RESULTS: In nonresponder patients (n = 17) geometric mean post-conjugate immunization (C) serum antibody concentrations (microg/ml) compared with post-polysaccharide (PS) concentrations were: (serotype, C vs. PS) 4, 1.11 vs. 0.30 (P = 0.000227); 6B, 0.46 vs. 0.20 (P = 0.017267); 9V, 0.82 vs. 0.29 (P = 0.002163); 14, 1.88 vs. 0.27 (P = 0.000615); 18C, 0.98 vs. 0.32 (P = 0.021962); 19F, 1.24 vs. 0.34 (P = 0.002844); and 23F, 0.87 vs. 0.16 (P = 0.000194). In responder patients (n = 67), after 1 dose of the polysaccharide vaccine, geometric mean antibody concentrations were: 4, 1.05; 6B, 0.96; 9V, 1.55; 14, 1.65; 18C, 1.62; 19F, 1.30; and 23F, 1.02. CONCLUSIONS: Our results show that a pneumococcal conjugate vaccine is capable of inducing an IgG response in patients with recurrent infections who had failed to mount an adequate response to the polysaccharide vaccine. Conjugate vaccines may be of value in the management of children with recurrent pneumococcal respiratory infections.

Adolescent↗
PubMed1991

Loss of visual function associated with microalbuminuria in diabetes mellitus: a pilot study.

Visual function loss has been documented in diabetes mellitus in relation to flicker and contrast. However, no direct correlation between the degree of loss in sensitivity and the level of retinopathy has been established. It has been suggested that such non-invasive psychophysical procedures actually reflect metabolic disturbances within the diabetic retina. This study investigates the possibility of whether early nephropathy demonstrated by microalbuminuria, is an indicator of microangiopathy which may be a cause of retinal disturbance leading to a loss of visual function. The visual function of a group of diabetics showing microalbuminuria was studied. Contrast and flicker threshold were measured and the results compared with those obtained with an age-matched control diabetic group. The procedures used effectively separated the two groups and raises the issue of incorporating psychophysics in retinal screening programmes.

Albuminuria↗
PubMed1985

Rat liver glutaminase. Regulation by reversible interaction with the mitochondrial membrane.

Partially purified rat liver mitochondrial glutaminase shows a sigmoidal dependence on glutamine concentration, and an absolute requirement for inorganic phosphate as activator. Reconstitution with a mitochondrial membrane fraction changes the kinetic properties of the enzyme making the glutamine dependence more hyperbolic and reducing the concentration of phosphate required for half-maximum activation. Glutaminase activity in isolated mitochondria is known to be increased as a result of mitochondrial swelling. In mitochondria suspended in isotonic medium, the properties of glutaminase resemble of the isolated enzyme while in swollen mitochondria the kinetic properties revert to those exhibited by the enzyme in association with the mitochondrial membrane. It is postulated that mitochondrial glutaminase is regulated in situ by reversible association with the inner mitochondrial membrane which is mediated by mitochondrial swelling. This mechanism may explain the short-term hormonally induced activation of the enzyme observed in isolated hepatocytes.

Animals↗
PubMed1982

Physiologic and anatomic development of the photoreceptors of normally-reared and dark-reared rabbits.

The postnatal development of the rod photoreceptor of normally-reared and dark-reared pigmented rabbits was studied using physiological and anatomical methods. The late receptor potential (LRP) was recorded in vitro and the threshold and maximum amplitude determined. The same specimens used in the electrophysiological studies were then prepared for microscopy, and rod cell outer and inner segment dimensions and photoreceptor spacing were determined. In the light-reared animals a small LRP was first recorded at 5 days, but only at very high stimulus intensities. Thereafter, there was a rapid decrease in the threshold and an increase in the amplitude of the LRP. The threshold and amplitude of the LRP reached adult values at 14 days. Of the anatomical parameters, maturation of inter-receptor spacing (14 days) is clearly associated with the attainment of the adult LRP amplitude levels. Outer segment length was also adultlike by 14 days of age and thus paralleled physiological maturity of the photoreceptor. Changes over time in the mean diameter and length of rod cell inner segments (adultlike at 21 days) follows the pattern of ontogenetic maturation of the LRP. These findings imply a close relationship during ontogeny between the LRP and development of the outer segment. In dark-reared pups there is a delay in the maturation of the photoreceptor mosaic, but by 4 weeks of age, physiological characteristics of the photoreceptor are adultlike.

Aging↗
PubMed1982

The effect of bacterial peptidoglycans on the immune response of hamsters to influenza virus vaccines.

The immune response of hamsters to influenza virus vaccine incorporating peptidoglycans derived from Streptomyces griseus was investigated. The results showed that although inoculation of a subunit influenza virus vaccine together with a peptidoglycan elicited a markedly increased serum HI antibody response compared to that induced by the subunit vaccine alone, pre-treatment of animals with peptidoglycans resulted in a suppression of the antibody response to the vaccine haemagglutinin antigen. The immunosuppressive effect was dose-related, and could be shown by adoptive transfer experiments to be transferred by spleen cell preparations from peptidoglycan-treated hamsters. The reasons for these findings, and their implication for the use of peptidoglycans as 'carriers' in influenza virus subunit vaccines, are discussed.

Animals↗