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Biomedical subjects

C Mason

Publications and source records attributed to C Mason.

At least 37 records · Page 2Linked to original sources
PubMed2001

Dental health indices and caries-related microflora in children with severe haemophilia.

The purpose of this work was to investigate the prevalence of dental caries, bacterial dental plaque, gingivitis, enamel defects and caries- related microflora in children with severe haemophilia. Thirty-eight children with severe haemophilia (factor VIII and IX < 2 U dL(-1)) were recruited from Great Ormond Street Hospital for Children and matched for age, gender and ethnicity with healthy control children from the Eastman Dental Institute. Indices were recorded for decayed, missing, and filled teeth and surfaces in both the deciduous dentition (dmfs/dmft) and the permanent dentition (DMFS/DMFT). The plaque and gingivitis scores and developmental enamel defects were also recorded. The caries-related microflora was sampled and cultured for Streptococcus mutans, and Lactobacilli and Candida species. A significantly greater proportion of children with severe haemophilia were caries-free compared with the controls (36.7% vs. 13.3%; P=0.04). Both the DMFS and DMFT were significantly greater in the controls (3.6 and 2.8, respectively) compared with the haemophilia group, (0.8 and 0.7; P=0.007 and P=0.04). The plaque score for the permanent dentition only was significantly greater for the control children (24.2) compared with the haemophilia group, (10.2; P=0.04). The mean number of colony forming units of S. mutans was significantly greater in the control group compared with the haemophilia group (P=0.05). We conclude that children with severe haemophilia have a significantly lower prevalence of dental caries compared with matched, healthy controls.

Adolescent↗
PubMed2001

Traditional tooth bud gouging in a Ugandan family: a report involving three sisters.

It has been reported in the literature that some rural populations of Sub-Saharan and Eastern Africa and other isolated areas around the world, practise gouging or enucleation of primary tooth buds to cure childhood illnesses. The unerupted primary canine tooth bud is believed to be the cause of febrile illness, diarrhoea, and vomiting; prevalent in infants in these areas of the world. Tooth bud gouging has implications for the developing dentition, and is a potential risk to the health and life of the child. Reported prevalence ranges from 22%-90%. From the information in this case report, the practise of tooth bud gouging is no longer confined to rural areas and may well be performed by communities that have emigrated to the UK. The three sisters described, now resident in the UK, suffered tooth gouging in a city clinic in Uganda. The damage caused to the primary and permanent dentition is described and treatment planning and options are suggested for each case to restore structure and function. Appropriate provision of healthcare and education could avoid the potential long-term damage to the health of the child and their developing dentition by the practise of tooth bud gouging, whether it occurs in the developing or developed world.

Child↗
PubMed2001

Thioguanine for refractory psoriasis: a 4-year experience.

BACKGROUND: A variety of systemically administered drugs are used to treat psoriasis, including methotrexate, cyclosporine, acitretin, and hydroxyurea. Unfortunately, some patients are unresponsive to these agents. For others, side effects and cumulative toxicity prevent continued use. OBJECTIVE: Our purpose is to report the results of thioguanine (6-thioguanine) treatment of 21 patients with refractory psoriasis. METHODS: We conducted a retrospective review of the treatment courses of 21 patients with psoriasis who were treated with thioguanine. Daily dosing and pulse dosing were both used, from 20 mg two times a week to 120 mg daily. All patients had been treated with other systemic therapies, and the majority (86%) had been treated with methotrexate. RESULTS: Patient outcome (response to treatment relative to baseline) was classified into 3 groups: those with more than 90% improvement, those with between 50% and 90% improvement, and those with less than 50% improvement. Outcome data were based on the patient's subjective rating of disease severity before the start of thioguanine therapy and during the entire treatment course. Of the 18 patients able to be evaluated, 14 of 18 (78%) had dramatic improvement (>90%); 3 of 18 (17%) had lesser improvement (50%-90%); and only 1 of 18 had less than 50% improvement. The mean duration of treatment was 15.5 months. The primary side effect was myelosuppression, mild in 9 of 18 (white blood cell counts ranging from 1600-3700/microL; platelet counts ranging from 90,000-122,000/microL, and hematocrit values ranging from 24%-31%), and severe in 1 of 18 (white blood cell count of 1300/microL, platelet count of 17,000/microL, and hematocrit of 20%). CONCLUSION: Thioguanine appears to be an effective treatment for patients with severe recalcitrant psoriasis. Myelosuppression is a significant, but easily monitored side effect that can now be more accurately predicted by determining thiopurine methyltransferase levels before starting thioguanine. Further prospective studies are needed to establish criteria, which will maximize efficacy of this drug in the treatment of psoriasis and minimize toxicity.

Adult↗
PubMed2001

The radiographic localization of impacted maxillary canines: a comparison of methods.

This study compared two different radiographic techniques for localization of impacted maxillary canines: vertical parallax (from a panoramic and a maxillary anterior occlusal radiograph) and magnification (from a single panoramic radiograph). The radiographs and the information regarding the impacted canines were obtained retrospectively from records of patients treated in the Day Stay Unit of the Eastman Dental Hospital. The two different radiographic techniques were tested blind and compared for localization of the impacted canine by six examiners. The 'gold standard' used for the radiographic comparisons was the true position of the canine as recorded at operation. The results showed a wide variation between the six examiners in the prediction of the canine position with the two different techniques. Localization with vertical parallax was more successful overall than with magnification, although the difference failed to reach significance. Seventy-six per cent of the impacted canines could be successfully located with vertical parallax and 66 per cent with magnification. Further analysis showed that, while almost 90 per cent of the palatally impacted canines could be correctly detected with both techniques, less than half of the buccal canines could be detected with parallax and only one in 10 buccal canines could be detected with magnification. If a canine is suspected to be buccally placed from its appearance on a panoramic film and cannot be palpated, further views are justified.

Cuspid↗
PubMed2001

Evaluation of a new selective medium for methicillin-resistant Staphyloccocus aureus.

The aims of this study were to evaluate the performance of a new medium, desferrioxamine oxacillin tellurite egg-yolk mannitol salt agar (DOTEMSA) in detecting methicillin-resistant Staphylococcus aureus (MRSA) and then to compare this medium against the Public Health Laboratory Service (PHLS) recommendation of mannitol salt agar (Oxoid) with oxacillin (OMSA) and Baird-Parker medium with ciprofloxacin (BPC) for the isolation of MRSA. The individual selective agents contained in DOTEMSA were tested against isolates of coagulase-negative staphylococci (CNS) and the medium with all constituents was challenged with various bacteria. Routine screening specimens were plated out on OMSA, BPC and DOTEMSA and the plates were incubated and examined at 24 and 48 h. Tellurite, desferrioxamine and oxacillin each inhibited the majority of CNS isolates; only three (of 103) grew in the presence of all three agents. Sixty-two of 63 isolates of MRSA grew on DOTEMSA and 59 produced lipase. Most other bacteria were inhibited. In all, 184 MRSA isolates were isolated from 540 screening specimens. The sensitivity of OMSA, BPC and DOTEMSA was 42%, 81% and 51% at 24 h, and 60%, 89% and 89% at 48 h. At 48 h, the combination of BPC and DOTEMSA detected 99% of MRSA isolates. Seventy, 49 and one non-MRSA isolates needed investigation for each of the three media respectively. A proposed strategy for MRSA screening would use BPC and DOTEMSA, examining BPC at 24 h and both media at 48 h. Provisional reports could then be issued at 24 h on the basis of rapid agglutination tests to confirm isolates as S. aureus from BPC and at 48 h on the basis of typical colonies from DOTEMSA.

Cell Division↗
PubMed2001

The appeal cycle in three cultures: an exploratory comparison of child development.

Mother-child behaviors were studied in three cultural groups: Caucasian American (CA), overseas Japanese (JPN), and Chinese Vietnamese (CVN) immigrants. The children were sixteen to twenty-five months old, and the appeal cycle, with its descriptive analytic method, was the research paradigm. Group differences were found in appeal cycle occurrence and phase frequencies. CA mothers promoted independence through encouragement of decision making and toddler-initiated play, and through nonintrusive interactions. Neither JPN nor CVN mothers encouraged independence. JPN mothers were subtly directive; CVN mothers overtly so. Generally, CA toddlers played independently, evincing a beginning capacity for self-regulation. JPN and CVN toddlers reacted to separation by staying close to their mothers, and fewer were observed to play independently than in the CA group. CVN toddlers played independently more frequently than JPN toddlers, but less frequently than CA toddlers. Quantitative measures of dyadic behaviors generally support the descriptive findings, though methodological constraints did not permit comparison of phase sequencing. The findings reflect cultural differences in child development thought to influence psychic structure formation.

Adult↗
PubMed2001

The dental health and caries-related microflora in children with craniosynostosis.

OBJECTIVE: To compare levels of dental caries, bacterial dental plaque, gingivitis, enamel defects, and caries-related microflora in children with and without craniosynostosis. STUDY GROUP: Fifty-seven children with craniosynostosis and their matched controls. OUTCOME MEASURES: The decayed, missing, and filled teeth and surfaces in both the deciduous (dmfs and dmft) and the permanent dentition (DMFS and DMFT). The plaque and gingivitis scores and developmental enamel defects were also recorded. The caries-related microflora was sampled using an alginate swab and the prevalence of Streptococcus mutans and Lactobacillus and Candida species were recorded. RESULTS: The dmfs (p <.02) and dmft (p <.01) were significantly greater in the control children. The plaque score for the deciduous dentition only (p <.02) and also the gingivitis score for the permanent teeth only (p <.008) in the craniosynostosis group were significantly greater. The total aerobic bacterial count (p <.004), anaerobic count (p <.002), and Candida count (p <.05) were significantly greater in the control group. The proportion of S. mutans both as a percentage of the total anaerobic count (p <.04) and the total streptococcal count (p <.05) was significantly greater in the control group.

Acrocephalosyndactylia↗
PubMed2001

Exorcising excision: medico-legal issues arising from male and female genital surgery in Australia.

Genital surgery is one of the most controversial and contested practices, yet it is frequently described and referred to with little or no attention to cultural and social context. This article examines the practice, performed on both men and women, and the extent to which it clashes with issues of consent and capacity, as well as multicultural concepts of toleration for minority group practices. It then questions why female genital surgery, unlike male genital surgery, is legally prohibited in Australia. It argues that such legal gender bias stems from a liberal conception of "tolerance" and the limits of consent in Australia, placing female genital surgery in an "unacceptable" category and male genital surgery in an "acceptable" category.

Australia↗
PubMed2001

Balancing flexibility for the employer and the employee: a case study of the development of annualized hours employment contracts.

As with many forms of flexible working, Annualized Hours (AH) systems offer potential benefits to both the employer and the employee. However, the flexibility requirements of employers and employees often conflict. Therefore, when a large food manufacturing organization decided to redesign its AH system, it employed an independent consultancy to act as neutral third party. The consultancy provided technical expertise and assistance in developing an AH system that optimised productivity and was acceptable to the workforce. Data are presented, obtained from focus groups conducted throughout the organization, describing some of the potential difficulties of implementing an AH system. Drawing upon these data, a number of new AH systems were proposed and modelled using specialist software tools. The design process is described, together with the advantages and difficulties associated with use of the software tools. It is concluded that the key elements in the process of designing AH systems are centred around issues of trust and communication; the involvement of a broad range of interested parties, through a process of carefully managed group facilitation; and the need for adequate technical support in the development and evaluation of AH systems.

Computer Simulation↗
PubMed2001

Reducing night shift exposure: a pilot study of rota, night shift and age effects on sleepiness and fatigue.

The reduction of exposure to longer runs of successive night duties is often one of the aims of 'best practice' intervention. The objective of this pilot study was to examine the effects of a change in rota upon sleepiness and fatigue, and potential age-related issues in relation to the change. Participants were 102 police officers, mean age 33.60 (sd 6.11), mean shiftwork experience = 10.56 years (sd 6.84). Testing occurred at least one month before the change from the existing 'Ottawa' system to a new rota that split a run of 7 consecutive night shifts into blocks of 3 and 4 within the rota cycle, and 6 months after the change. Measures of critical flicker fusion, subjective fatigue and sleepiness, and stimulant intake were taken in relation to selected night shifts on both rotas. Older officers tended to report higher fatigue and sleepiness, and higher caffeine intake than the younger shiftworkers irrespective of rota or shift. The findings tend to suggest that the change of rota had little effect but that age may play a substantial role in responses to night work.

Adult↗
PubMed2001

Shiftwork locus of control effects in police officers.

Personality and experientially-based differences are suggested to moderate the negative effects of shiftworking. This investigation was one of a series of studies aimed at examining the relationship between internal locus of control (internality) and commonly reported outcomes of exposure to shiftworking. The study concentrated on whether or not shiftwork-specific internality appeared to be associated with better experiences for two groups of shiftworkers on different shift rotas. The Shiftwork Locus of Control (SHLOC) scale was completed by each group along with a range of outcome measures (including: sleep disturbance, alertness on shift, psychological well-being, disturbance of social and family life, and fatigue). The analyses controlled for for age, shiftwork experience and years of service effects. The results showed that for the majority of outcome variables, the higher internality was associated with significantly lower levels of shiftwork problems, especially when compared to the low internality group. The findings of this study further support the use of shiftwork-specific locus of control in shiftwork research as an indicator of potentially better tolerance, and possibly as part of an occupational health monitoring process to aid the targeting of interventions.

Adaptation, Psychological↗
PubMed2001

Age and the subjective experience of shiftwork.

The objective of this study was to examine age related effects of shiftwork albeit difficult to tease apart the natural effects of aging, and lifestyle or behaviour, or job done, over time and the shifts a person works. This is an issue of concern because the numbers of shiftworkers over 45 are increasing. Participants were 306 police officers who had worked a new rota for approximately 6 months. Three age groups were compared (1 = 20-32.9, 2 = 33-39.9, 3 = 40+) using a range of shiftwork-related measures and multivariate analysis of covariance (controlling for shiftwork experience and other individual differences). Younger officers tended to report significantly better attitudes towards their shiftwork, better adjustment to night-bound shifts, greater job satisfaction and organisational commitment, lower fatigue and longer sleep durations. Older shiftworkers reported significantly higher morningness and lower sleep need than the younger officers. This concurred with existing research that implicates such variables in the mechanism(s) involved in age-related tolerance to shiftwork. It was also evident that the older group tended to resort to greater caffeine intake on all shifts. The findings offer tentative support for the position that age can be linked to depleted shiftwork tolerance but the issue of establishing the relative impacts of aging, lifestyle, behaviour, work type and the rota worked remains to be a challenge.

Adaptation, Psychological↗
PubMed2000

HLA-DR-promiscuous T cell epitopes from Plasmodium falciparum pre-erythrocytic-stage antigens restricted by multiple HLA class II alleles.

Previously, we identified and established the antigenicity of 17 CD8+ T cell epitopes from five P. falciparum Ags that are restricted by multiple common HLA class I alleles. Here, we report the identification of 11 peptides from the same Ags, cicumsporozoite protein, sporozoite surface protein 2, exported protein-1, and liver-stage Ag-1, that bind between at least five and up to 11 different HLA-DR molecules representative of the most common HLA-DR Ags worldwide. These peptides recall lymphoproliferative and cytokine responses in immune individuals experimentally immunized with radiation-attenuated Plasmodium falciparum sporozoites (irradiated sporozoites) or semi-immune individuals naturally exposed to malaria in Irian Jaya or Kenya. We establish that all peptides are recognized by individuals of each of the three populations, and that the frequency and magnitude of helper T lymphocyte responses to each peptide is influenced by the intensity of exposure to P. falciparum sporozoites. Mean frequencies of lymphoproliferative responses are 53.2% (irradiated sporozoites) vs 22.4% (Kenyan) vs 5.8% (Javanese), and mean frequencies of IFN-gamma responses are 66.3% (irradiated sporozoites) vs 27.3% (Kenyan) vs 8. 7% (Javanese). The identification of HLA class II degenerate T cell epitopes from P. falciparum validates our predictive strategy in a biologically relevant system and supports the potential for developing a broadly efficacious epitope-based vaccine against malaria focused on a limited number of peptide specificities.

Adolescent↗
PubMed2000

Transport and health: en route to a healthier Australia?

We have been slow to recognize the impact that decisions about transport, land use and infrastructure have on health. Apart from encouraging a sedentary lifestyle, reliance on motor vehicle transport has a range of adverse health effects (traffic accidents, air and noise pollution, and greenhouse gas emissions). Physical activity equivalent to 30 minutes (in total) of brisk walking on all, or most, days of the week provides preventive and protective benefits for a wide range of health conditions (including cardiovascular disease, diabetes, depression and osteoporosis). "Active transport"--walking, cycling and/or using public transport instead of car travel--could have dual health benefits by providing physical activity and reducing the adverse health effects of motor vehicle transport. Doctors, medical administrators and health advocates can encourage the use of "active transport", and influence community-based programs and policy development about land use planning and travel demand management.

Australia↗
PubMed2000

Growth cone form, behavior, and interactions in vivo: retinal axon pathfinding as a model.

Studies in vitro have revealed a great deal about growth cone behaviors, especially responses to guidance molecules, both positive and negative, and the signaling systems mediating these responses. Little, however, is known about these events as they take place in vivo. With new imaging methods, growth cone behaviors can be chronicled in the complex settings of intact or semi-intact systems. With the retinal projection through the optic chiasm as a model, we examined the hypothesis previously drawn from static material that growth cone form is position-specific: growth cone form in fact reflects specific behaviors, including rate and tempo of extension, that are more or less prominent in different locales in which growth cones are situated. Other studies show that growth cones interact with cells along the pathway, both specialized nonneuronal cells and other neurons, some expressing known guidance molecules. The present challenge is to bridge dynamic imaging with electron microscopy and molecular localization, in order to link growth cone behaviors with cell and molecular interactions in the natural setting in which growth cones extend.

Animals↗
PubMed2000

A prospective follow-up study of ECT outcome in older depressed patients.

BACKGROUND: This study examined the relationship between age and outcome of electroconvulsive therapy (ECT). METHOD: This was a naturalistic, prospective follow-up of 81 consecutive in-patients with primary major depression. ECT outcome was compared for three age groups - under 65, 65-74 and 75 years and over - on the Hamilton Rating Scale for Depression (HRSD), Global Assessment of Functioning scale (GAF) and clinical outcome rating scale. Assessments were performed pre-ECT, immediately post-ECT, 1-3 years later and, for patients suspected of having dementia, 5 years later. RESULTS: At post-ECT and follow-up, improvement on HRSD and clinical outcome ratings were comparable for patients in the three age groups. Improvements on GAF were also comparable post-ECT, but not between post-ECT and follow-up. At follow-up, 35.7% of the oldest group had dementia. Importantly, patients who did and did not develop dementia were clinically indistinguishable prior to ECT. The number and severity of common adverse events were similar pre- and post-ECT and were not associated with age. CONCLUSIONS: Depressive outcome and adverse effects of ECT are largely independent of age. Older patients receiving ECT appear to have a higher risk of developing dementia, possibly underpinned by cerebrovascular disease.

Adult↗