Reduction of sound levels with antinoise in MR imaging

A combination of active and passive techniques was used to reduce the sound levels in magnetic resonance imagers. These techniques were integrated into an existing audio system. Measurements of sound reduction varied with the protocol being used and averaged 9.9 dB with coaxial cabling and 14.2 dB with fiberoptic conduction of the feedback signal to a controller. Patient comfort and communication were improved.     

Effects of thoracic spinal cord transection on colonic motor activity in rats

The resting colonic motor activity before and consecutively after spinal cord transection was recorded in male Sprague-Dawley rats. Recording probes were anchored surgically in the ascending and descending colon. Pressure changes were recorded on a dynograph using a low compliance perfusion system. A motility index took into account the amplitude, duration and frequency of contractions. Following a baseline recording animals were subjected either to spinal cord transection at T4 level or a sham operation. The recording sessions continued regularly on alternate days for the observation period of 3 weeks. Transection of the thoracic spinal cord markedly reduced the motility index of the distal colon on the first postoperative day. However, the motor activity gradually returned to pre-operative values after 7 days. Sham surgery did not influence the motor activity. These findings suggest that colonic motor activity is influenced by spinal shock and probably by different neural mechanisms mediating proximal and distal activities of the colon in rats.     

Immunity to MCA-induced rat sarcomas: Analysis of in vivo and in vitro results

Three in vivo techniques were used to establish the specificity of tumor immunity induced after sensitization of F344 rats to syngeneic MCA-induced sarcomas: (1) post-excision resistance to tumor challenge, (2) passive tumor neutralization (the Winn test), and (3) concomitant immunity. In general, these assays revealed unique non-crossreactive antigens associated with each of three sarcomas, FMF1, FMM2, and FMM3. However, spleen cells from tumor-sensitized rats did not demonstrate cell-mediated cytotoxicity in vitro corresponding to the specificity of tumor resistance in vivo. In the (³H)-proline cytotoxicity assay, spleen cells from FMM3 tumor-bearing rats or from FMM3 tumor-immune rats were not selectively cytotoxic for cultured FMM3 target cells. Parallel analysis of spleen cells from normal or FMM3-sensitized rats using the Winn assay and the (³H)-proline assay revealed that (1) spleen cell cytotoxicity in vitro did not correlate with effective tumor protection in vivo; and (2) normal spleen cells were cytotoxic against cultured sarcoma target cells in vitro and inhibited tumor growth in vivo. Thus, passive tumor protection by normal spleen cells in vivo corresponded with the demonstration of natural cytotoxicity in vitro, but induced specific anti-tumor reactivity was observed only in vivo.     

Effect of aprotinin on in vitro cerebral endothelial ICAM-1 expression induced by astrocyte-conditioned medium

BACKGROUND AND OBJECTIVE: Aprotinin administration may decrease the incidence of stroke associated with coronary artery bypass surgery by an unknown mechanism. Astrocytes exposed to hypoxia produce proinflammatory cytokines and upregulate intercellular adhesion molecule (ICAM)-1 on cerebral endothelium. This study investigated the effects of aprotinin on cerebral endothelial activation by hypoxic astrocytes in vitro. METHODS: Mouse astrocytes were exposed to hypoxia in an anaerobic chamber for 4 h followed by reoxygenation for 24 h. Astrocyte-conditioned medium (ACM) collected from mouse astrocytes subjected to hypoxia/reoxygenation (HR) or normoxia were applied to mouse cerebral endothelial cell (MCEC) cultures for 4 and 24 h in normoxia. Endothelial cells were preincubated for 1 h with aprotinin (1600 KIU mL(-1)) prior to exposure to ACM. Flow cytometry was used to estimate endothelial ICAM-1 expression. Interleukin (IL)-1beta space concentrations in ACM were estimated with enzyme-linked immunosorbent assay (ELISA). Repeated comparisons were made using analysis of variance (ANOVA) and post hoc Tukey test as appropriate. P < 0.05 was considered significant. Data is presented as mean (standard deviation, SD). RESULTS: MCEC ICAM-1 expression was greater after 24 h exposure to HR-ACM compared to normoxic-ACM (mean channel flouresence (MCF) 107.5 (4.5) vs. 74.3 (4.5), respectively, P < 0.001). ICAM-1 expression was decreased by aprotinin preincubation compared to control (MCF 91.0 (1.1) vs. 107.5 (2.1), P = 0.006). Supernatant IL-1beta concentrations in astrocytes exposed to HR were greater than those exposed to normoxia (7.1 (0.2) vs. 4.1 (0.2), P = 0.01). CONCLUSIONS: This may be a neuroprotective mechanism associated with aprotinin administration.     

Chest wall dose in MammoSite breast brachytherapy: radiobiologic estimations of late complication risk based on dose-volume considerations

PURPOSE: To estimate the risk of late effects in women treated with MammoSite brachytherapy (MBT), the balloon catheters of which were placed near the ribs. METHODS AND MATERIALS: Upon reviewing 93 plans, 16 patients (17%) treated with MBT were considered to have received a high chest wall dose (>or=120% isodose line in contact with a rib). A dose-volume histogram was generated for this rib, and its distance from the MBT balloon measured. Using the linear quadratic equation, the equivalent dose, delivered in 10 fractions, to the dose that causes a 5% and 50% risk of rib late effects at 5 years using 2Gy per fraction, was calculated to be 37 and 44Gy, respectively. The rib volume receiving greater than or equal to these doses (V37 and V44) was correlated to the balloon-to-rib distance. Chest wall signs, symptoms, and radiologic findings for all 16 patients were recorded. RESULTS: The median balloon-to-rib distance was 4.8mm. The median values of V37 and V44 were 13.5% and 3.3%, respectively. All patients with a V37>or=15% and V44>or=5% had a minimum balloon-to-rib distance of <5mm. Two patients reported treatment-related chest wall tenderness (both had balloons placed <5mm from the chest wall), but neither presented with radiologic complications. CONCLUSIONS: Sixteen patients considered to receive relatively high chest wall doses had less than one-third of their primary rib volume being exposed to the estimated TD 5/5 and TD 50/5 doses. Therefore, we estimate the risk of late effects in women treated with MBT, the balloon catheters of which placed near the ribs were negligible, and believe that MBT remains a safe and effective treatment for selected patients with early stage breast cancer.     

Use of the SF-8 to assess health-related quality of life for a chronically ill,low-income population participating in the Central Louisiana Medication Access Program (CMAP)

Objectives: The utility of the SF-8 for assessing health-related quality of life (HRQL) is demonstrated. Race and gender differences in physical component (PCS) and mental component (MCS) summary scores among participants in the CENLA Medication Access Program (CMAP), along with comparisons to the United States population are made. Methods: Age-adjusted multiple linear regression analyses were used to compare 1687 CMAP participants to the US population. Internal race and gender comparisons, adjusting for age and the number of self reported diagnoses, were also obtained. The paired t-test was used to assess 6-month change in PCS and MCS scores for a subset of 342 participants. Results: CMAP participants have PCS and MCS scores that are significantly 10–12 points lower than the US population, indicating lower self-reported HRQL. Females have significantly higher PCS and significantly lower MCS than males. African–Americans have significantly higher MCS than Caucasians. Significant increases in both PCS and MCS were observed for the subset of participants after 6months of intervention. Conclusions: The expected lower baseline PCS and MCS measures and the expected associations with age and number of diagnoses indicate that the SF-8 survey is an effective tool for measuring the HRQL of participants in this program. Preliminary results indicate significant increases in both PCS and MCS 6months after intervention.     

Caring for depressed patients in rural communities: general practitioners' attitudes, needs and relationships with mental health services

OBJECTIVE: To examine the needs and practices of rural GPs and their relationships with local acute mental health services, particularly in the provision of care to depressed patients. DESIGN: Postal survey. SETTING: Rural general practices. SUBJECTS: Ninety-nine GPs (63 males, 36 females) from the Hunter Valley region of NSW, Australia. MAIN OUTCOME MEASURES: GPs' self-reported contact rates, confidence, needs and beliefs. RESULTS: Depression was the most commonly seen mental disorder, with an average of 1.44 patients per GP per month referred to local acute mental health services, most commonly for suicidality. The preferred form of feedback after the referral of a depressed patient was a follow-up letter, while the most requested type of patient management support was cognitive behavioural therapy (CBT) groups. GPs were most confident in recognising depression, compared to other mental disorders except anxiety, and they were most confident in treating depression, compared to all other mental disorders. The most common barrier to providing care for depressed patients was reported to be 'time constraints' on GPs. CONCLUSIONS: The challenge for mental health services is to develop ways to collaborate more effectively with GPs in the provision of psychological services for depressed patients in rural communities.