Sociocultural deterrents to mammographic screening in Jamaica.

Objective: Less than five per cent of eligible Jamaican women had mammograms in 2003. The sociocultural determinants and the perceptual barriers modulating screening behaviour in Jamaican women are unclear. We sought to investigate sociocultural effects, in particular knowledge and fear of the procedure on mammographic screening behaviour in Jamaican women.

Mammographic referral patterns for two breast imaging units in Jamaica.

Objective: In countries that have instituted national mammographic screening programmes, mortality from breast cancer has decreased by as much as 63%. Although mortality rates from breast cancer in Jamaica are high, there is no national mammographic screening programme. In this context, opportunistic screening, which depends on contact between healthcare provider and patient, as well as self-referral become important.

Effect of conversion from a fee-for-service plan to a capitation reimbursement system on a circumscribed outpatient radiology practice of 20,000 persons.

Purpose: To assess the effect of a capitation reimbursement plan with attendant changes in service arrangements on the utilization of radiologic services, financially on the payer, and on the satisfaction of patients and referring physicians.

Materials And Methods: Outpatient radiologic services for a defined population of 20,000 company employees and their dependents were converted from a point-of-service managed care plan to a capitation payment plan. Under the capitation plan, nonemergent outpatient diagnostic imaging was performed at a newly constructed imaging center staffed by general radiologists.

Functional magnetic resonance imaging reveals brain regions mediating the response to resistive expiratory loads in humans.

Obstructive lung disease is the most common form of respiratory disturbance. However, the location of brain structures underlying the ventilatory response to resistive expiratory loads is unknown in humans. To study this issue, midsagittal magnetic resonance images were acquired in eight healthy volunteers before and after application of a moderate resistive expiratory load (30 cmH2O/liter/s), using functional magnetic resonance imaging (fMRI) strategies (1.

A quantitative physiologic model of blood oxygenation for functional magnetic resonance imaging.

Rationale And Objectives: Variations in venous deoxyhemoglobin levels in response to neuronal activation represent a complex interplay between focal changes in cerebral blood flow (CBF), cerebral blood volume (CBV), and regional metabolism. The authors present a mathematic model that characterizes the response of venous oxygenation to changes in these variables.

Methods: Using a mass balance approach, the equations for a simple input-output model are derived and solved using Matlab.

Identification of human brain regions underlying responses to resistive inspiratory loading with functional magnetic resonance imaging.

Compensatory ventilatory responses to increased inspiratory loading are essential for adequate breathing regulation in a number of pulmonary diseases; however, the human brain sites mediating such responses are unknown. Midsagittal and axial images were acquired in 11 healthy volunteers during unloaded and loaded (30 cmH2O; 1 cmH2O = 98 Pa) inspiratory breathing, by using functional magnetic resonance imaging (fMRI) strategies (1.5-tesla MR; repetition time, 72 msec; echo time, 45 msec; flip angle, 30 degrees; field of view, 26 cm; slice thickness, 5 mm; number of excitations, 1; matrix, 128 x 256).

Dynamic magnetic resonance imaging of human Rolandic cortex.

Rolandic cortex was imaged with magnetic resonance (MR) in nine subjects while performing a motor activation task. Imaging was performed by a volumetric, T2-weighted pulse sequence in a conventional 1.5 Tesla scanner during both resting conditions and volitional toe flexion and extension of the dominant foot.

MR imaging signal response to sustained stimulation in human visual cortex.

The response of signal intensity to transient (on-off) motor and sensory stimulation has been well studied; however, the dependence of signal response on the duration of stimulus requires further characterization. The objective of this study was to determine the time course of signal response in the human visual cortex to prolonged, sustained stimulation and to examine possible contributory physiologic mechanisms. Nine healthy volunteers underwent magnetic resonance (MR) imaging during sustained visual stimulation with light-proof binocular goggles.

Localization of putative neural respiratory regions in the human by functional magnetic resonance imaging.

In humans, the location of brain regions responsible for mediating the ventilatory response to CO2 remains unknown. Most of the available knowledge has been derived from animal studies or from pathophysiological correlations in patients presenting altered control of breathing. Magnetic resonance imaging at a specific pulse sequence designed to assess changes in brain tissue microcirculation was performed in 11 healthy volunteers, during steady-state conditions, while breathing 100% O2 or 5% CO2-95% O2.

Os odontoideum in identical twins: perspectives on etiology.

Most authorities favor the hypothesis of an acquired etiology of os odontoideum. We present the cases of identical twin sisters with os odontoideum in association with a congenital partial fusion of the posterior elements of the second and third cervical vertebrae, and discuss the implications. We believe that this is the first report of familial os odontoideum in a context which suggests a genetic etiology.

Effects of activation on lipid and lipoprotein metabolism in murine macrophages.

The effects of activation on lipid and lipoprotein metabolism were examined in resident murine macrophages, inflammatory cells elicited by thioglycolate, primed cells elicited by pyran copolymer, and activated cells elicited by Corynebacterium parvum. Low density lipoprotein receptors were reduced by 70%, while scavenger receptors were reduced 60% in activated cells. Basal cholesteryl ester and triglyceride synthesis were increased fourfold in activated cells, whereas the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase was high in resident cells and progressively declined by greater than 80% in activated cells.