Feasibility of using interpolated contours of targets and organs at risk in intensity‐modulated radiation therapy treatment planning for advanced‐stage nasopharyngeal carcinoma

To assess the dosimetric effect of using interpolated contours in planning intensity‐modulated radiation therapy (IMRT) for advanced T‐stage nasopharyngeal carcinoma. The present study focused on T3–T4 tumours where the proximity of targets to neurological organs poses a stringent test on the feasibility of such an approach. Contours of targets and organs were delineated on CT images of 2.5‐mm interval and a reference IMRT plan was generated. An investigative (INV) IMRT plan was then generated with the same planning protocol, but based on interpolated contours that replaced deleted contours on alternate slices. The reference and INV plans were compared. Regarding target coverage, all targets in the INV plans met the acceptance criteria except for the PTV in one case. Regarding organs, the mean dose to 1% volume of the brainstem and spinal cord in the INV plans were kept below their dose limits. No significant differences in the mean doses to others organs were found. Satisfactory target coverage and protection of critical organs to a degree similar to full‐scale contouring could be achieved with use of interpolated contours. The saving in manpower time for contouring is expected to significantly improve the throughput of the IMRT planning process.     

Steady-state evoked potentials to amplitude modulated tones in the monkey.

A frequency-specific, objective assessment of hearing thresholds is required for use in subjects unable to perform behavioural audiometry. One such method using steady-state evoked potentials (SSEPs) in response to amplitude-modulated tones was evaluated in an experimental animal, the macaque monkey. An amplitude-modulation frequency of 165 Hz was found to produce optimum response detection in the anaesthetised animal. Auditory thresholds determined by a computerised automatic response detection system accurately reflected behavioural thresholds previously described in this species.     

Translation of the Leisure Satisfaction Scale into French: a validation study

Few standardized instruments are available for clients who speak languages other than English. The purpose of the study was to present and describe the process of translating an English standardized assessment into another language. Using the translation/validation methodologies described by Haccoun (1987) and Vallerand (1989), the Leisure Satisfaction Scale (LSS) was translated into French and then statistically validated. All correlations between both language versions of the LSS were found to be significant at the 0.01 level. Confirmatory factor analysis results were positive. Study findings indicate that the Haccoun (1987) and Vallerand (1989) methodologies provide clinicians with another option for ensuring culturally sensitive and relevant evaluations. Further research is needed to globally assess the measurement properties of the French version of this instrument.     

Childhood medulloblastoma in northwest England 1954 to 1997: incidence and survival

The incidence, survival patterns, and presenting symptoms of children with medulloblastoma were studied. Data were ascertained from the Manchester Tumour Registry which is population-based and has collected data on all childhood malignancies in northwest England since 1954. Incidence rates standardized to the European standard population were calculated and Poisson regression models were used to examine temporal changes in the incidence rates during the period 1954 to 1997. Kaplan-Meier survival curves were derived and used to study changes in survival patterns. World-standardized incidence rates were 5.5 per million child years in males and 3.4 per million child years in females. Incidence rates increased from the 1950s to the 1980s but have declined recently. The 5-year survival rate has improved from 29 to 58% with similar rates for males and females. The 1-year survival rate has also improved, but females had worse survival at this point (58%) than males (75%). The type of symptom or sign at presentation is strongly affected by age, with 10 of the 22 recorded symptoms or signs showing significant age differences. The older the child is, the more likely is the presentation to show pressure features of headache, vomiting, and ophthalmic signs. Younger children present with non-specific features such as lethargy, behavioural disturbance, or increasing head size. Ataxia is seen in about 75% of children across the age range.     

Orthodontic retention: why when and how?

Retention is normally required after active orthodontic tooth movement to hold the teeth in their new positions. This article reviews the principles of orthodontic retention and describes common retention regimes and appliances.     

Sarcoglycans in vascular smooth and striated muscle

Sarcoglycans are transmembrane proteins important in the maintenance of proper muscle function. Together, the sarcoglycans form a heteromeric complex that interacts with dystrophin, dystroglycan, and filamin C to form a mechanosignaling complex. Mutations in the genes encoding sarcoglycan can produce cardiomyopathy and muscular dystrophy. Studies of patients and animal models have emphasized the variability in penetrance and severity of cardiomyopathy. In animal models of sarcoglycan mutations, muscular dystrophy develops owing to loss of the sarcoglycan complex at the membrane of skeletal myocytes. Cardiomyopathy similarly develops with evidence of focal areas of degeneration and necrosis, as well as loss of sarcoglycan at the cardiomyocyte membrane. Vascular spasm has been noted as a feature of sarcoglycan-mediated cardiomyopathy. Recent evidence suggests that disruption of the smooth muscle sarcoglycan complex is not required for the development of vascular spasm and that vascular spasm arises from a vascular smooth muscle cell-extrinsic process.     

Comparative effects of mirtazapine and fluoxetine on sleep physiology measures in patients with major depression and insomnia

BACKGROUND: Sleep complaints are common in patients with major depressive disorder (MDD). Both MDD and antidepressant drugs characteristically alter objective sleep measures. This study compares the effects of mirtazapine and fluoxetine on sleep continuity measures in DSM-IV MDD patients with insomnia. METHOD: Patients (N = 19) received initial baseline polysomnography evaluations over 2 consecutive nights. Subjects were randomly assigned to either fluoxetine (20-40 mg/day) or mirtazapine (15-45 mg/day) treatment for an 8-week, double-blind, double-dummy treatment trial. Single-night polysomnograms were conducted at weeks 1, 2, and 8, with depression ratings assessed at baseline and weeks 1, 2, 3, 4, 6, and 8. Statistical analysis was performed by repeated-measures analysis of variance followed by Dunnet's post hoc analyses. RESULTS: Patients receiving mirtazapine (N = 8) had significant improvement in objective sleep physiology measures at 8 weeks. Improvements in sleep latency, sleep efficiency, and wake after sleep onset were significant after only 2 weeks of mirtazapine treatment. No significant changes in sleep continuity measures were observed in the fluoxetine group (N = 11). Both groups improved clinically in mood and subjective sleep measures from baseline, with no differences between groups. CONCLUSION: These data demonstrate the differential effects of mirtazapine and fluoxetine, with significant improvement in favor of mirtazapine, on objective sleep parameters in MDD patients with insomnia.     

Altered venous function and deep venous thrombosis following proximal femoral fracture

The effect of surgery for femoral neck fracture on lower limb venous blood flow and its relationship to deep vein thrombosis was investigated in 179 patients. Blood flow was measured using strain gauge plethysmography before surgery, in the 1st week after surgery, and at 6 week review. There was a significant reduction in both venous outflow and venous capacitance, affecting both fractured and non-fractured legs but significantly greater in the fractured leg. Venous function remained significantly impaired in both lower limbs 6 weeks after surgery.There was a significant correlation between the reduction in venous function and the development of deep vein thrombosis.