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Biomedical subjects

James S Brown

Publications and source records attributed to James S Brown.

At least 19 recordsLinked to original sources
PubMed2006

The effect of exercise on nasal uptake of ozone in healthy human adults.

The nose may help protect the lower respiratory tract from the effects of ambient ozone by scrubbing ozone from inspired air. Reductions in both nasal resistance and nitric oxide production with exercise may influence the efficiency of ozone uptake in the nose. Nasal ozone uptake was measured in 10 healthy volunteers before and after 15 min of moderate bicycle exercise. Ozone (0.2 parts/million) was pulled through both nostrils and out of the mouth at a constant flow while the subjects closed their epiglottises. Nasal uptake of ozone was determined by comparing the ozone concentration entering the nostrils to that exiting the mouth. Average preexercise uptake of ozone was 56 +/- 7.8 and 37 +/- 4.9% at 10 and 20 l/min, respectively. These averages did not significantly differ from those immediately postexercise (55 and 37%). Nasal ozone uptake increased significantly (P < 0.001) with decreasing flow rate, but intersubject variability in uptake could not be predicted by nasal volume or cross-sectional areas (as measured by acoustic rhinometry) or endogenous nitric oxide production. However, the percent change in ozone uptake after exercise, within an individual, was correlated with both 1) percent change in nasal volume (r = 0.70 at 10 l/min) and 2) percent change in the rate of volumetric expansion between the nasal valve and turbinates (r = 0.82 at 10 l/min). These results may be useful for assessing human risk associated with ozone exposure during exercise.

Adaptation, Physiological↗
PubMed2006

A questionnaire survey of current UK practice for adjuvant radiotherapy following surgery for oral and oropharyngeal squamous cell carcinoma.

A postal questionnaire was sent to 281 members of the British Association of Head and Neck Oncologists (BAHNO) to survey, which patients should receive adjuvant radiotherapy following primary surgery for oral and oropharyngeal squamous cell carcinoma (O&OSCC). Two hundred and one clinicians were involved in decision making for adjuvant radiotherapy in O&OSCC, of which, 132 (66%) responded. Apart from general agreement that patients with involved margins or extracapsular spread (ECS) should have adjuvant radiotherapy and that in patients with small tumours with clear margins and no neck metastasis, radiotherapy should be avoided, opinion was divided. Considerable variation in opinion in the UK was identified for a subgroup of intermediate risk patients as to whether they should have adjuvant radiotherapy. The majority of respondents (95%) would consider submitting patients to a prospective multi-centre trial. There is a need for research regarding adjuvant radiotherapy for O&OSCC patients at intermediate risk of relapse following primary surgery.

Carcinoma, Squamous Cell↗
PubMed2006

Improving access for patients - a practice manager questionnaire.

BACKGROUND: The administrative and professional consequences of access targets for general practices, as detailed in the new GMS contract, are unknown. This study researched the effect of implementing the access targets of the new GP contract on general practice appointment systems, and practice manager satisfaction in a UK primary health care setting. METHODS: A four-part postal questionnaire was administered. The questionnaire was modified from previously validated questionnaires and the findings compared with data obtained from the Western Health and Social Services Board (WHSSB) in N Ireland. Practice managers from the 59 general practices in the WHSSB responded to the questionnaire. RESULTS: There was a 94.9% response rate. Practice managers were generally satisfied with the introduction of access targets for patients. Some 57.1% of responding practices, most in deprived areas (Odds ratio 3.13 -95% CI 1.01 - 9.80, p = 0.0256) had modified their appointment systems. Less booking flexibility was reported among group practices (p = 0.006), urban practices (p < 0.001) and those with above average patient list sizes (p < 0.001). Receptionists had not received training in patient appointment management in a quarter of practices. Practices with smaller list sizes were more likely than larger ones to utilise nurses in seeing extra patients (p = 0.007) or to undertake triage procedures (p = 0.062). CONCLUSION: The findings demonstrated the ability of general practices within the WHSSB to adjust to a demanding component of the new GP contract. Issues relating to the flexibility of patient appointment booking systems, receptionists' training and the development of the primary care nursing role were highlighted by the study.

Administrative Personnel↗
PubMed2005

Particle inhalability at low wind speeds.

Accurate quantification of the dose delivered by aerosol exposures is essential for estimating the risk of potential adverse health effects. The fraction of airborne particles that can enter the nose or mouth during inhalation is referred to as the inspirable particulate mass fraction. This inhalable fraction is equivalent to delivered dose for particles greater than approximately 25 microm (aerodynamic particle diameter, d(ae)), which deposit completely and almost exclusively in the extrathoracic airways. Particle inhalability at high wind speeds (1-9 m/s) has been well characterized. However, there is a paucity of data describing the inhalability of particles at low wind speeds (< or =0.3 m/s), which are typical of indoor environments. High-wind-speed criteria poorly describe inhalability at low wind speeds. Based on the aspiration efficiencies of blunt and sharp-edged inlets, a function was developed for oral inhalability, P(I(O)), of particles at low wind speeds. This function predicts a slow decline in P(I(O)) from 0.95 at d(ae)= 8 microm, to 0.5 at d(ae) = 74 microm, and 0.1 at d(ae)= 175 microm. Data available from the literature for inhalability at relatively low wind speeds during oral breathing are well described by this logistic function (r(2)= 0.69).

Aerosols↗
PubMed2005

Oral rehabilitation after treatment for head and neck malignancy.

BACKGROUND: Advances in the management of oral malignancy have resulted in significant improvements in survival and functional outcome. Ablation of oral tissues and radiotherapy render many patients unable to wear conventional prostheses, and these patients are, thus, candidates for oral rehabilitation with osseointegrated implants. We aim to present outcomes and complications of such treatment over a 14-year period in a single unit. METHODS: Data were collected for 81 consecutive patients, most of whom had received microvascular free flap reconstruction after surgical ablation of oral squamous cell carcinoma. Three hundred eighty-six implants were placed after a delay of 12 months after surgery. Sixty-five percent of implants were placed in the anterior mandible. Radiotherapy was used in 47% of the patients, and hyperbaric oxygen treatment was routinely used in irradiated subjects during the latter half of the series. Retrospective analysis of implants and prostheses was made by use of case notes, radiographs, and a computerized database. RESULTS: Data are presented for 364 of the 386 implants in 77 of the 81 patients after a median follow-up of 4 years. Two hundred sixty-five (73%) of the implants were in function supporting prostheses, 56 (15%) had been lost, and 43 (12%) were present but not loaded (ie, "sleepers"). Implant loss seemed patient specific and was also correlated with host bone type. Thirteen percent of patients in whom implants were placed in the mandible lost at least one implant, and the equivalent values for the maxilla was 40%. Thirty-six percent of patients in whom implants were placed in bone graft or flap lost at least one implant. The effects of implant manufacture, dimensions, radiotherapy, and hyperbaric oxygen did not reach statistical significance in this series. Cases of a second primary malignancy were noteworthy; however, the impact of recurrence was minimized by the delay between resection and rehabilitation. Of the 42 fixed and 29 removable prostheses fitted, 12 (17%) failed. CONCLUSIONS: Implants placed in mandible were reliable, but failure rates in vascularized bone graft and maxilla were higher. Radiotherapy did not seem to prejudice implant survival, and hyperbaric oxygen had no demonstrable benefit in this series. Despite some persistent soft tissue problems and implant loss, most patients reached a successful prosthetic and functional outcome.

Adolescent↗
PubMed2004

The impact of neck dissection on health-related quality of life.

OBJECTIVE: To compare health-related quality of life in patients having no neck dissection and those having a selective dissection, with particular reference to shoulder dysfunction. DESIGN: Prospective study. SETTING: Regional Maxillofacial Unit, University Hospital Aintree, Liverpool, England. PATIENTS: Two hundred seventy-eight consecutive patients undergoing primary surgery for previously untreated oral and oropharyngeal squamous cell carcinoma between January 1, 1995, and December 31, 1999. MAIN OUTCOME MEASURE: The University of Washington Quality of Life questionnaire, administered on the day before surgery and at 6 months, at 12 months, and more than 18 months after surgery. RESULTS: No neck dissection was performed in 58 patients (21%), a unilateral dissection in 181 (65%), and a bilateral dissection in 39 (14%). Patients with no neck dissection and those with unilateral level III or IV dissections had similar mean scores for shoulder dysfunction, whereas patients with unilateral level V and bilateral level III and IV dissections recorded much worse scores on average. CONCLUSIONS: There is little subjective morbidity associated with shoulder dysfunction after a unilateral level III or IV neck dissection compared with patients undergoing primary surgery without a neck dissection. More extensive surgery in the neck, whether bilaterally removing levels I to III or IV or extending posteriorly to include level V, is associated with statistically significantly worse shoulder dysfunction.

Aged↗
PubMed2004

Comparison of miniplates and reconstruction plates in mandibular reconstruction.

BACKGROUND: The aim of this study is to compare complication rates of miniplates versus reconstruction plates in the fixation of vascularized grafts into segmental mandibular defects. METHODS: Retrospective analysis of 143 consecutive successful microvascular composite flaps performed between 1993 and 2001 was performed. Data were gathered from a computerized database, case notes and pathology reports. Complications were classified as dehiscence, infection, plate or bone removal. RESULTS: In the series, 49% of patients received miniplates, and 51% received plates. No significant differences in complication rates were found between those grafts fixed with miniplates (27%) and those with reconstruction plates (30%). Plate choice was primarily determined by consultant preference. No significant differences were found in patient, defect, treatment, or follow-up characteristics between the plate groups. Twenty-nine percent of patients had at least one late complication at the reconstructed site, and this was higher (39%) in those who had postoperative radiotherapy. CONCLUSIONS: No evidence was found in this study that the increased rigidity offered by reconstruction plates influences the rate of plate or bone removal, infection, or plate exposure. Thus, the decision to use reconstruction or miniplates is not dependent on the rate of plate complications.

Adult↗
PubMed2004

Longitudinal health-related quality of life after mandibular resection for oral cancer: a comparison between rim and segment.

BACKGROUND: Mandibular resection for oral cancer is often necessary to achieve an adequate margin of tumor clearance. Segmental mandibulectomy has been associated with a poor health-related quality of life (HRQOL), particularly before composite free tissue transfer to reconstruct the defect. Little is published in the literature contrasting the subjective deficit of segmental compared with rim resection. The aim of this study was to use a validated head and neck HRQOL questionnaire to compare rim and segmental mandibular resection in patients having primary surgery for oral cancer. METHOD: There were 224 consecutive patients between 1995 and 1999 who were treated by primary surgery for oral squamous cell carcinoma. One hundred twenty-tree had no mandibular resection, 44 had a rim resection, and 57 had a segmental resection. The University of Washington Quality of life questionnaire (UW-QOL) was administered before treatment, at 6 months, 12 months and after 18 months. RESULTS: Preoperatively, patients undergoing segmental resection reported significantly more pain, chewing problems, and a lower composite UW-QOL score. Postoperatively, the segment group tended to score worse at all time points, particularly in appearance, swallowing, recreation, and chewing; however, the difference between rim and segment was only seen in smaller resections without adjuvant radiotherapy. Little difference was seen between rim or segment for tumors < 4 cm with radiotherapy and between rim and segments for tumors > 4 cm. CONCLUSION: After segmental mandibulectomy and reconstruction using composite free tissue transfer, the UW-QOL scores were relatively good. The only 2 difference between rim and segments was noted in the small resections without radiotherapy, and some of this was reflected in differences at baseline.

Aged↗
PubMed2004

The influence of the pattern of mandibular invasion on recurrence and survival in oral squamous cell carcinoma.

BACKGROUND: Controversy exists over the predictive value of the presence and pattern of tumor invasion of the mandible in oral squamous cell carcinoma (SCC). Many authors have questioned increasing the classification of small tumors to T4 on the basis of mandibular invasion alone. There are little data on the influence of the pattern of invasion on prognosis. METHODS: We prospectively reviewed 100 consecutive mandibular resections for previously untreated oral SCC. Clinical and pathologic data collected included details of soft and hard tissue histologic findings. Outcomes included recurrence (local, regional, and distant metastases), disease-specific survival, and death from other causes. The median follow-up for survivors was 65 months. RESULTS: Of 100 cases, 65 involved segmental and 35 involved marginal resections. Sixty-two percent of mandibles were invaded by tumor. Local recurrence occurred in 21% and was strongly correlated with tumor size, nodal involvement, and pattern of soft tissue invasion. The 5-year disease-specific survival was 68%, and the crude survival was 50%. Mandibular invasion predicted for recurrence and disease-specific survival, even after correcting for the effects of other variables. The pattern of mandibular invasion (erosive/infiltrative) was also predicted for recurrence and disease-specific survival. CONCLUSIONS: Even in the presence of mandibular invasion, soft tissue factors are the most important determinants of prognosis. Upstaging tumors on the basis of mandibular invasion is justified. An infiltrative pattern of bone invasion is a marker of aggressive tumor biology and should be included in the pTNM classification.

Adult↗
PubMed2004

Deposition of coarse particles in cystic fibrosis: model predictions versus experimental results.

In patients with cystic fibrosis (CF), the lung regions most affected by infection are presumed to be poorly ventilated and, hence, difficult to treat with inhaled therapeutic aerosols. Current dosimetric models do not adequately describe regional particle deposition in CF. We have developed a multiple-path particle deposition model and compared model predictions with the observed pattern of coarse particle (5 microm, mass median aerodynamic diameter) deposition in ten CF patients and eight healthy volunteers. Our model divides the lung into quadrants, separated at lobar bronchi, representing apical and basal lung regions. The volume and ventilation of quadrants were experimentally determined from a xenon equilibrium and multi-breath washout, respectively. Regional ventilation in the healthy lung was assumed to be determined largely by regional compliance. In CF patients, the deviations in regional ventilation from that observed in the healthy subjects were assumed to be due to regional resistance. A "custom" lung morphology was calculated for each subject based on their lung volume (functional residual capacity plus one-half tidal volume) and ventilation to each quadrant. Input parameters for particle deposition calculations were "custom" lung morphology, breathing pattern, and inhaled particle size. Relative to healthy subjects, the CF patients had reduced ventilation to the apices and increased ventilation to the bases of the lung. In healthy subjects, the general pattern of particle deposition followed ventilation. However, in the CF patients, the model predicted increased particle deposition in the large airways of the apices (an obstructed and poorly ventilated region) and to a lesser extent in the basal lung (relatively healthier and better-ventilated region), whereas particle deposition in the parenchyma was only increased in the basal lung and was decreased or absent in the apical lung. Our modeling strategy improves estimates of regional aerosol deposition and may be useful for predicting breathing conditions and particle size for optimal drug delivery in a given CF patient.

Administration, Inhalation↗
PubMed2003

Correlation of mollicutes and their viruses with multiple sclerosis and other demyelinating diseases.

To identify infectious diseases likely involved in MS, the author previously correlated the geographical distribution of MS with the global distribution of tick-borne diseases. Tick-borne infectious agents include mollicutes or mycoplasmas. The current paper reviews evidence that mollicutes, especially spiroplasmas, or their viruses could be the initial exposure that causes MS. Mollicute infections, including the effects of their toxins, can be treated or prevented with gold salts or tetracyclines. If further research recommended by this review finds a role of mycoplasmas in MS, treatment of MS with gold with tetracycline should be evaluated.

Animals↗
PubMed2003

Health-related quality of life after maxillectomy: a comparison between prosthetic obturation and free flap.

PURPOSE: The purpose of this cross sectional study was to evaluate the health-related quality of life of patients following maxillectomy and to compare obturation and free flap reconstruction. PATIENTS AND METHODS: At the Regional Maxillofacial Unit in Liverpool, United Kingdom, between 1992 to 1996, 39 patients underwent maxillectomy for malignant pathology. Of these patients, 28 (10 underwent obturation and 18 underwent free tissue reconstruction) completed a postoperative semi-structured interview. Eight questionnaires were used to test aspects of health-related quality of life and function. RESULTS: The main findings were the associations between the size of maxillectomy defect and the University of Washington activity (-0.53; P =.005) and recreation (-0.70; P <.001) domains, and with the physical functioning (-0.58; P =.001) and quality of life (-0.51; P =.007) domains of the European Organization for Research and Treatment of Cancer questionnaire. No statistically significant differences were seen between the obturator and free flap groups. Borderline trends were for obturator patients to be more concerned about their appearance, to have more pain and soreness in their mouths, to be more aware of their upper teeth, more self-conscious and less satisfied with their upper dentures, and less satisfied with function. CONCLUSION: Similar subjective outcomes were found for both groups, and a larger longitudinal study is needed to test these relationships more rigorously.

Aged↗
PubMed2003

A comparison of the long-term morbidity following deep circumflex iliac and fibula free flaps for reconstruction following head and neck cancer.

Composite free tissue transfer has an established role in head and neck oncology for the reconstruction of the bony defect following tumor ablation, and while donor-site morbidity is variably reported, there is little consensus on the most favorable donor site. The fibula and deep circumflex iliac artery have distinct advantages in terms of the volume and length of bone in mandibular reconstruction. Few studies have compared their donor-site morbidity. The aim of this study was to compare the fibula and deep circumflex iliac artery flaps using a review of the case notes and cross-sectional review of patients attending a research clinic for validated orthopedic examination and completion of health-related quality-of-life questionnaires. Between February of 1993 and May of 2001, 44 fibula free flaps and 73 deep circumflex iliac artery free flaps were performed. Ninety-nine case notes and 36 patients were available for review of donor-site morbidity. Sixteen patients with fibula flaps and 20 patients with deep circumflex iliac artery flaps took part in the clinical examination component of the study, which was composed of a clinical examination by an orthopedic surgeon using the American Orthopedic Foot and Ankle Society ankle scoring system and the Harris hip scoring system, and two patient-completed questionnaires, the University of Washington Questionnaire and the Hospital Anxiety and Depression Scale. Subjective and objective markers of morbidity related to both flaps were similar in most parameters. However, fibula flaps were associated with more problems with donor-site healing, reduced power, and sensation. Poor orthopedic scores for both flaps were associated with notably poor scores on the University of Washington Questionnaire and the Hospital Anxiety and Depression Scale. The study would suggest that both deep circumflex iliac artery and fibula donor sites result in an acceptable and comparable morbidity for most patients, but in cases in which significant donor-site morbidity is encountered, health-related quality of life is significantly compromised.

Activities of Daily Living↗
PubMed2002

Ultrafine particle deposition and clearance in the healthy and obstructed lung.

Numerous epidemiologic studies have shown associations between exposure to particulate air pollution and acute increases in morbidity and mortality, particularly in persons with chronic obstructive pulmonary disease. The dosimetry of ultrafine particles in the human lung is poorly characterized. We studied the deposition and clearance of an ultrafine technetium-99m-labeled aerosol in 10 patients with chronic obstructive pulmonary disease and in 9 healthy subjects. Particle retention was followed for 2 hours after inhalation and again at 24 hours by gamma scintigraphy. Central-to-peripheral ratios indexed airway deposition. Particle accumulation in the liver was examined by quantifying activity below the right lung. The dose rate for an aerosol exposure of 10 micro g/m(3) was calculated. Patients had a significantly greater dose rate than healthy subjects (2.9 +/- 1.0 versus 1.9 +/- 0.4 micro g/h, p = 0.02). Central-to-peripheral ratios were slightly greater in patients than in healthy subjects (1.11 +/- 0.10 versus 1.01 +/- 0.11, p = 0.05). Clearance did not statistically differ between health and disease. On average, 24-hour retention was 85 +/- 8% (corrected for isotope dissolution). No accumulation in the liver's vicinity was observed. Data suggest that relative to healthy subjects, patients with moderate-to-severe airways obstruction receive an increased dose from ultrafine particle exposure.

Administration, Inhalation↗
PubMed2002

Phase-transfer catalyst separation by CO2 enhanced aqueous extraction.

CO2 is used to enhance the environmentally benign and efficient recovery of phase transfer catalysts with aqueous extraction; this method can alter the distribution of phase transfer catalysts so dramatically that even in dilute organic solutions they can be separated selectively from an organic reaction mixture with only a small fraction of the water required in a traditional aqueous extraction.

Journal Article↗