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Biomedical subjects

C Mason

Publications and source records attributed to C Mason.

At least 19 recordsLinked to original sources
PubMed2006

The Korean stem cell fiasco: shifting the focus.

No one could have failed to have seen the dramatic headlines surrounding Professor Woo Suk Hwang of the Seoul National University. Hwang claimed first place in the race to create patient-specific stem cells from cloned human embryos, only to be discredited shortly afterwards. This article discusses whether such high-profile negative publicity has damaged the regenerative medicine industry in general or whether it has merely shifted the stem cell focus away from South Korea.

Fraud↗
PubMed2005

Application of obesity treatment algorithms to Canadian adults.

OBJECTIVE: The purpose of this study was to apply obesity treatment algorithms to a representative sample of Canadians to determine their potential impact on the population. DESIGN: The Canadian Heart Health Surveys (1986-1992) were used to describe the prevalence of adults (18-64 y) that would be eligible for weight loss treatment according to the US NIH algorithm, which uses body mass index (BMI), waist circumference (WC), and the presence of two or more cardiovascular disease (CVD) risk factors. Similar algorithms based on CVD risk factors and a single measure of either BMI or WC alone were also evaluated. RESULTS: Using the NIH algorithm, 24% of Canadians (28% men, 19% women) would be identified for weight loss treatment. Virtually, all subjects received the same treatment recommendations when using BMI and CVD risk factors only, while 22% (23% men, 21% women) would meet the criteria for treatment using WC and CVD risk factors only. CONCLUSIONS: Approximately one in four Canadians would be eligible for weight loss treatment using the NIH obesity treatment algorithm. However, the algorithm may be improved through the incorporation of more sensitive WC thresholds.

Adolescent↗
PubMed2005

Correlation between genotype, phenotype and sex of rearing in 111 patients with partial androgen insensitivity syndrome.

OBJECTIVE: Partial androgen insensitivity syndrome (PAIS) is a heterogeneous group of intersex disorders characterized by a typical perineoscrotal hypospadias/micropenis phenotype, and a normal androgen-producing testis. Various mutations in the androgen receptor (AR) are known to cause PAIS. Phenotypic expression is widely variable and there are no agreed guidelines to determine the sex of rearing in individuals with borderline masculinization. We aimed to quantitatively assess the external genital phenotype in relation to AR genotype and sex of rearing and identify criteria that differentiate mutation positive (ARmt) from mutation negative (ARwt) PAIS patients. PATIENTS AND DESIGN: Cases with a diagnosis of PAIS were identified from the Cambridge Intersex Database. An external masculinization score (EMS) was used to quantify the degree of undermasculinization. Family history of AIS and details of the sex of rearing were recorded. Androgen binding was analysed in fibroblasts obtained from genital skin biopsies and mutational analysis of the AR was performed on genomic DNA extracted from peripheral blood. EMS and sex of rearing were compared in cases with similar mutations reported on the McGill International Database. RESULTS: Two hundred and sixty-three patients with PAIS were identified. Androgen receptor gene sequencing was performed in 111 patients. Twenty-seven (24%) had mutations. Family history of AIS was present in 61 and 21% of ARmt and ARwt patients, respectively. The median EMS was 3 in both groups. The majority of ARmt patients had abnormal binding and there was a tendency to a higher median testosterone rise on hCG stimulation in ARmt (9.3 nmol/l) compared with ARwt patients (6.9 nmol/l). All patients with EMS of 4 or more were raised as male but there was an overlap of sex of rearing in patients with an EMS less than 4. A wide variation of EMS in relation to genotype and sex of rearing was observed. CONCLUSION: The phenotype in PAIS is extremely variable and is rarely predicted by the AR genotype. Apart from the family history, there are no specific criteria to differentiate ARwt from ARmt. Sex of rearing is not entirely dependent on the EMS. Cultural issues, other modifying genes and response to androgen trials might be influencing factors. Collaborative studies with uniform protocols are needed to investigate infants with PAIS. Documenting phenotype, surgical procedures and outcome criteria are necessary to enable decision-making on the sex of rearing in patients with a lower range EMS.

Amino Acids↗
PubMed2005

Ectodermal dysplasia--an unusual dental presentation.

Ectodermal dysplasia (ED) is a rare group of disorders affecting the hair, teeth, nails and sweat glands to a variable degree. There is a wide range of clinical presentation of ED. Missing teeth or abnormal tooth form may be the first indicator of the presence of the disorder. There is typically hypodontia with microdontia. We present an unusual case of ED with severe hypodontia and macrodontia affecting all first permanent molar teeth. We also consider the classification and presentation of this disorder.

Anodontia↗
PubMed2005

Stem cells are big news, but are they big business?

Future health care will involve treatment with stem cells and tissue engineering. This article, the first in a series reporting on the scientific breakthroughs in this area and relating them to the medical device industry, describes the science.

Animals↗
PubMed2005

Tissue engineering skin: a paradigm shift in wound care.

Tissue-engineered skin for the treatment of burns and ulcers is a clinical success, but making it commercially viable is more problematic. This article examines the industry, its techniques and suggests the way forward.

Animals↗
PubMed2004

Doppler optical coherence tomography for measuring flow in engineered tissue.

The engineering of human tissue represents a major paradigm shift in clinical medicine. Early embodiments of tissue engineering are currently being taken forward to the clinic by production methods that are essentially extensions of laboratory manual procedures. However, to achieve the status of routine large-scale clinical practice, automation and scale-out processes are required. This in turn will require the development of reliable on-line monitoring and control systems. This paper examines one demand of crucial importance, namely the real time in vitro monitoring of the flow characteristics through growing tissue since this has a complex interrelationship. Doppler optical coherence tomography (DOCT) is a recently developed imaging technique for studying the rheological properties of tissues in vivo. Capable of non-invasive imaging in real time with high resolution, it is potentially ideal for the continuous monitoring of engineered tissues in vitro. As a base line, the current status of DOCT in vivo is therefore reviewed. This paper also reports the first preliminary use of DOCT in tissue engineering. The application described involves the imaging of a fully developed laminar flow through a combined tissue fabrication/bioreactor with a tissue-engineered construct (substitute blood vessel) in situ.

Bioreactors↗
PubMed2004

The potential of optical coherence tomography in the engineering of living tissue.

The better repair of human tissue is an urgent medical goal and in order to achieve a safe outcome there is a parallel need for sensitive, non-invasive methods of assessing the quality of the engineered tissues and organs prior to surgical implantation. Optical coherence tomography (OCT) can potentially fulfil this role. The current status of OCT as an advanced imaging tool in clinical medicine, developmental biology and material science is reviewed and the parallels to the engineering of living tissue and organs are discussed. Preliminary data are also presented for a tissue engineering bioreactor with in situ OCT imaging. The data suggest that OCT can be utilized as a real time, non-destructive, non-invasive tool to critically monitor the morphology of tissue-engineered constructs during their fabrication and growth.

Animals↗
PubMed2004

Morbidity following dental treatment of children under intubation general anaesthesia in a day-stay unit.

OBJECTIVES: To determine which variables were best related to the overall morbidity of a child undergoing dental general anaesthetic (GA) and then to use these variables to determine those factors that might influence the extent and severity of morbidity experienced by healthy children following dental GA. SAMPLE AND METHODS: Data were collected on anxiety, pain and morbidity, GA procedure and dental procedure from 121 children attending a day stay GA unit for dental treatment. Patients were interviewed preoperatively, postoperatively before discharge then four further times over the next 148 h. Data were analysed using multivariate regression. RESULTS: Thirty-one per cent of subjects had restorative work, 60% had at least one tooth extracted, 54% had a surgical procedure. Use of local analgesia reduced postoperative pain whilst an increase in the number of surgical procedures increased it. Increase in anaesthetic time was related to increased odds of feeling sleepy and nauseous, females were more likely to complain of sleepiness or weakness. Feelings of dizziness were increased if the patient was given local analgesia during the procedure. CONCLUSIONS: Pain following dental GA was the most prevalent and long lasting symptom of postoperative morbidity in this study. Reductions in operating time and improvement in pain control have the potential to reduce reported morbidity following dental GA.

Adolescent↗
PubMed2004

Ergonomic analysis of New York apple harvest work using a Posture-Activities-Tools-Handling (PATH) work sampling approach.

Although back, neck, and shoulder strains are common among migrant and seasonal orchard workers, little data currently exist regarding the ergonomic factors contributing to this problem. We adapted Posture-Activities-Tools-Handling (PATH) instruments and methods for ergonomic job analysis of apple harvest work in three New York orchards, and used the resulting protocol to quantify hazardous activities, loads, and postures. Using a prototype developed previously, we trained twelve contract orchard observers with classroom training and supervised orchard practice. The PATH data were then collected on 14 orchard workers over four days (2,900 observations). Mean coefficients of variation ranged from a low of 0.212 (standing leg neutral) to a high of 0.603 (trunk moderate flexion). Most frequently observed activities were: picking (62.9%), placing and moving apples in the bag (8. 7%), and walking (8.1%). Weight bearing (>10 lb, >4.54 kg) was observed 78.5% of the time throughout a range of activities. Apple harvest work is comparable with other ergonomically high-risk occupations. Future research should focus on low-cost interventions that reduce load and awkward postures.

Agricultural Workers' Diseases↗
PubMed2002

Informed consent: optimism versus reality.

OBJECTIVE: To determine whether parents of children attending the outpatient general anaesthesia (OPGA) session at the Eastman Dental Hospital, London fully understand the proposed treatment. DESIGN: Observational study supported by structured questionnaires and interviews. SETTING: Casualty service in the Department of Paediatric Dentistry and the Victor Goldman Unit (a day-stay general anaesthetic unit) of the Eastman Dental Hospital. MAIN OUTCOME MEASURES: The parents' understanding of the consent was assessed based on their knowledge of the actual treatment procedure, the type of anaesthesia to be used and the number and type of teeth that would be extracted. RESULTS: Fifty-two of the 70 subjects (74%) approached completed both parts of the survey (interviews one and two). Results showed that 40% of the written consent obtained from the parents were not valid. The subjects' knowledge of the proposed treatment improved on the day of the actual treatment although 19% of them still did not fully understand the procedure. There was a statistically significant increase in the proportion of valid consent on the day of the actual treatment. Many of the subjects had no knowledge of the type of anaesthesia that would be used for their children but were more aware of the number and type of teeth that were going to be extracted. The time interval between the consent process and the actual treatment did not have any significant effect on the subjects' understanding of the consent, but it implied that with time the subjects' knowledge improved. CONCLUSION: A proportion of subjects did not fully understand the proposed treatment procedure even after being adequately informed. Appropriate measures should be taken to ensure that the patients or their guardians truly understand the proposed treatment.

Adolescent↗
PubMed2002

The trouble with teething--misdiagnosis and misuse of a topical medicament.

For many clinicians and parents "teething" remains a convenient diagnosis to explain all manner of local and systemic upset in the young child. Many therapies are on the market to help alleviate the symptoms of primary tooth eruption. In this article we highlight the problems of "teething" as a diagnosis by presenting a case where an initial misdiagnosis of teething compromised a patient's life. The same patient then suffered from topical analgesic misuse during the recovery period.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2001

Resolving factor analysis.

Bilinear data matrices may be resolved into abstract factors by factor analysis. The underlying chemical processes that generated the data may be deduced from the abstract factors by hard (model fitting) or soft (model-free) analyses. We propose a novel approach that combines the advantages of both hard and soft methods, in that only a few parameters have to be fitted, but the assumptions made about the system are very general and common to a range of possible models: The true chemical factors span the same space as the abstract factors and may be mapped onto the abstract factors by a transformation matrix T, since they are a linear combination of the abstract factors. The difference between the true factors and any other linear combination of the abstract factors is that the true factors conform to known chemical constraints (for instance, nonnegativity of absorbance spectra or monomodality of chromatographic peaks). Thus, by excluding linear combinations of the abstract factors that are not physically possible (assuming a unique solution), we can find the true chemical factors. This is achieved by passing the elements of a transformation matrix to a nonlinear optimization routine, to find the best estimate of T that fits the criteria. The optimization routine usually converges to the correct minimum with random starting parameters, but more difficult problems require starting parameters based on some other method, for instance EFA. We call the new method resolving factor analysis (RFA). The use of RFA is demonstrated with computer-generated kinetic and chromatographic data and with real chromatographic (HPLC) data. RFA produces correct solutions with data sets that are refractory to other methods, for instance, data with an embedded nonconstant baseline.

Journal Article↗
PubMed2001

Analysis of pulmonary surfactant by Fourier-transform infrared spectroscopy following exposure to Stachybotrys chartarum (atra) spores.

Lung cells are among the first tissues of the body to be exposed to air-borne environmental contaminants. Consequently the function of these cells may be altered before other cells are affected. As gas exchange takes place in the lungs, changes in cellular function may have serious implications for the processes of oxygen uptake and carbon dioxide elimination. In order for these processes to occur, the lung must maintain a high degree of expandability. This latter function is accomplished in part by the pulmonary surfactant which is synthesized and released by alveolar type II cells. Earlier studies have shown that exposure to gas phase materials such as smoke or organic solvents can alter the composition and function of the surfactant. The present study examines the ability of highly toxigenic mold spores to alter surfactant composition. Stachybotrys chartarum spores suspended in saline were instilled into mouse trachea as described earlier. After 24 h, the lungs were lavaged and the different processing stages of surfactant isolated by repeated centrifugation. Intracellular surfactant was isolated from the homogenized lung tissue by centrifugation on a discontinuous sucrose gradient. Samples were extracted into chloroform-methanol, dried and analyzed by Fourier-Transform infrared spectroscopy (FTIR). Exposure to S. chartarum induced an overall reduction of phospholipid among the three surfactant subfractions. The intermediate and spent surfactant fractions in particular were reduced to about half of the values observed in the saline-treated group. The relative distribution of phospholipid was also altered by spore exposure. Within the intracellular surfactant pool, higher levels of phospholipid were detected after spore exposure. In addition, changes were observed in the nature of the phospholipids. In particular strong intramolecular hydrogen bonding, together with other changes, suggested that spore exposure was associated with absence of an acyl chain esterified on the glycerol backbone, resulting in elevated levels of lysophospholipid in the samples. This study shows that mold spores and their products induce changes in regulation of both secretion and synthesis of surfactant, as well as alterations in the pattern of phospholipid targeting to the pulmonary surfactant pools.

Animals↗
PubMed2001

Accusations that hospital staff have abused pediatric patients.

OBJECTIVE: Study objectives were to describe a hospital Child Protection Team's (CPT) efforts to develop and implement a protocol for systematic evaluation and management of accusations that hospital staff have abused pediatric patients, and to learn how to avoid problematic patient encounters and cope with existing accusations. METHOD: This study reports on a retrospective series of cases from one pediatric hospital between 1982 and 1996. It includes a survey of national children's hospitals' experience from 1990 through 1995. RESULTS: After initial complaints to our hospital's CPT, it became apparent that procedures were inadequate to protect the safety of patients and rights of the accused. A protocol for reporting, evaluation, and management of accusations was developed and implemented by the CPT. Thirty-four accusations of abuse of children by staff were reviewed. Seventeen of the physical abuse cases included bruising, fractures, rough handling, and verbal abuse. Eighteen sexual abuse complaints included touching and sexual statements. Complaints were substantiated in 23% of the accusations, and a third of the identified staff members were fired or resigned. Child victims had a high frequency of chronic illness. They and their families frequently had histories of prior abuse, mental illness, and social disarray. These factors made children more likely to become victims of real abuse and to misinterpret standard hospital procedures as abusive. All service areas of the hospital and types of hospital staff were accused of patient abuse. CONCLUSIONS: Few children's hospitals have formal protocols for internal management of or training programs to avoid complaints. Institutions and their staff who care for children should anticipate abuse complaints, train them in risk reduction methods, and develop accusation management plans.

Child↗
PubMed2001

"Side effects" of ECT are mainly depressive phenomena and are independent of age.

BACKGROUND: The aetiology of reported side effects of electroconvulsive therapy (ECT) is unclear. We examined the interaction of depression and age on adverse neuropsychological and putative side effects of ECT. METHOD: Inpatients (N=81; median age 70 years) with major depression were assessed prospectively pre-ECT, immediately post-ECT and 1-3 years later. Patients were administered the Hamilton Rating Scale for Depression (HRSD), the Global Assessment of Functioning scale (GAF) and neuropsychological tests from the Wechsler Memory Scale. Side effects and total burden scores were rated pre- and post-treatment. RESULTS: HRSD and GAF scores improved with treatment after ECT, but the prevalence and total burden of side effects were unchanged. Side effect burden was related to depression level before and after ECT. Improvement in depression correlated with reduction in side effect burden. There was a significant decline in side effect burden after controlling for change in depression. Patients' scores on neuropsychological measures did not appear to change after ECT or between pre-ECT and follow-up. Re-analysis, allowing for age, chronicity of depression, medication use and development of dementia, did not alter the findings. LIMITATIONS: lack of a control group, lack of information on ECT technique, incomplete data sets and limited neuropsychological testing. CONCLUSIONS: ECT, an effective treatment for depression, does not cause significant side effects or neuropsychological impairment, which are more likely to be depressive phenomena. ECT appears to be safe for old (> or =65 years) and very old (> or =75 years) patients, who do not appear to be more susceptible to adverse effects.

Adult↗