Organic dust exposures from compost handling: case presentation and respiratory exposure assessment

This study was designed to determine the effects of age by decade on the efficacy of digital rectal examination (DRE) and serum prostate-specific antigen (PSA) for early detection of prostate cancer in men aged fifty and over. A prospective multicenter clinical trial was conducted at six university centers. All 6,630 male volunteers underwent a serum PSA (Hybritech, Tandem) determination and DRE. Quadrant biopsies of the prostate were performed if PSA was > 4 ng/mL or DRE suspicious. A total of 1,167 biopsies were performed, and 264 cancers were detected. The cancer detection rate increased from 3 percent in men aged fifty to fifty-nine to 14 percent in men eighty years or older (p < 0.0001). PSA detected significantly more of the total cancers than DRE at all age ranges (p < 0.05). The positive predictive values (PPV) for PSA were 32 percent (50-59 years), 30 percent (60-69 years), 34 percent (70-79 years), and 38 percent (80+ years). The corresponding PPVs for DRE were 17 percent, 21 percent, 25 percent, and 38 percent. Eighteen percent of the cancers were detected solely by DRE, whereas 45 percent of cancers were detected solely by PSA. Thus, the use of both tests in combination provided the highest rate of detection in all age groups. One hundred-sixty patients underwent radical prostatectomy and pathologic staging. Cancer was organ-confined in 74 percent (25/34) of men aged fifty to fifty-nine, 76 percent (65/86) of men aged sixty to sixty-nine, and 60 percent (24/40) of men aged seventy or over (chi 2, < 70 vs. > or = 70, p < 0.05). Early detection programs yield a lower, yet still substantial, cancer detection rate in younger men, and there is a greater likelihood for detection of organ-confined disease in this age range. Younger men have the longest projected life expectancy and, therefore, the most to gain from early prostate cancer detection.     

In vivo chronoamperometric measures of extracellular serotonin clearance in rat dorsal hippocampus: contribution of serotonin and norepinephrine transporters

The effects of blockade of serotonin (5-HT) and norepinephrine (NE) transporters (SERT and NET, respectively) on the removal of locally applied 5-HT from extracellular fluid (ECF) were examined using in vivo chronoamperometry. Male Sprague-Dawley rats were anesthetized with chloralose/urethane, and a Nafion-coated, carbon fiber electrode attached to a multibarrel micropipette was positioned into either the dentate gyrus or CA3 region of the dorsal hippocampus. Pressure ejection of 5-HT elicited reproducible electrochemical signals of similar peak amplitude and time course in both structures. Local application of the selective serotonin reuptake inhibitors (SSRI) fluvoxamine and citalopram prolonged the clearance of 5-HT in both brain regions and also increased signal amplitude in the CA3 region. These effects were abolished in rats pretreated with 5, 7-dihydroxytryptamine (5,7-DHT), a selective 5-HT neurotoxin. The NE uptake inhibitors desipramine (DMI) and protriptyline did not alter the 5-HT signal in the CA3 region but prolonged the clearance of 5-HT in the dentate gyrus; this effect was absent in rats pretreated with 6-hydroxydopamine (6-OHDA), a selective catecholamine neurotoxin. The prolongation of the removal of 5-HT from the ECF in the dentate gyrus caused by fluvoxamine or desipramine was of comparable magnitude and was dose dependent. Furthermore, per picomole of 5-HT applied, the signal amplitude and clearance time were significantly increased in the dentate gyrus of rats lesioned with either 5,7-DHT or 6-OHDA. Only 5,7-DHT treatment caused this effect in the CA3 region. From these data, it is inferred that in certain regions of brain (dentate gyrus), both the SERT and NET contribute to the active clearance of exogenously applied 5-HT.     

Do behavioral responses mediate or moderate the relation between cardiovascular reactivity to stress and parental history of hypertension?

To examine whether differences in behavioral responses to stress mediated or moderated the relation between cardiovascular response to stress and parental history of hypertension, 64 healthy undergraduates--16 men with hypertensive parents (PH+), 16 men without hypertensive parents (PH-), 16 PH+ women, and 16 PH- women--participated in a mental arithmetic task, mirror tracing task, and 2 interpersonal role plays. PH+ participants exhibited higher resting heart rates than PH - participants and higher resting systolic blood pressures (SBPs) than PH- women. PH+ participants exhibited greater SBP responses to tasks and engaged in more negative verbal and nonverbal behavior across tasks than PH- counterparts. Differences in behavioral responding neither mediated nor moderated the observed relation between parental history status and SBP response to stress. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electromyography as a measure of peak and cumulative workload in intermediate care and its relationship to musculoskeletal injury: an exploratory ergonomic study

Injury rates in Intermediate Care (IC) facilities are high and the factors related to these injuries are unclear. The objectives of this exploratory sub-study, which is part of a large multi-faceted study in 8 IC facilities are to: (1) evaluate EMG measured over a full-shift in the back and shoulders of 32 care aides (CAs) as an indicator of peak and cumulative workload (n = 4 x 8 facilities); investigate the relationship between EMG measures and injury indicators; and explore the relationship between EMG measures and other workload measurements. Lumbar EMG was converted to predicted cumulative spinal compression and ranged in CAs from 11.7 to 22.8 MNs with a mean of 16.4 MNs. Average compression was significantly different during different periods of the day (p < 0.001) with highest compression during pre-breakfast when CAs assist most with activities of daily living. Significant differences were found in average compression between low and high injury facilities for 3 of 5 periods of the day (p < 0.010). Peak compressions exceeding 3400 N occurred for very little of the workday (e.g. 11.25s during the 75 min period pre-breakfast). Peak neck/shoulder muscle activity is low (99% APDF ranged from 8.33% to 28% MVC). Peak and cumulative spinal compression were significantly correlated with lost-time and musculoskeletal injury rates as well as with total tasks observed in the CAs (p < 0.01). Perceived exertion was only correlated with peak compressions (p < 0.01). Facilities with low injury rates provided significantly more CAs (p < 0.01) to meet resident needs, and subsequently CAs performed fewer tasks, resulting in less peak and cumulative spinal loading over the day.     

Validation of automated spectrofluroimetry for measurement of regional organ perfusion using fluorescent microspheres

The fluorescent microsphere (FM) method for determination of regional organ blood flow is labor intensive, requiring processing of 100 s to 1000 s of samples per organ. To save time and reduce handling errors, we developed an automated fluorescence analysis system by interfacing a commercially available spectrofluorimeter and sample delivery unit to a PC, operated by a Windows95(R)-based program, WINFAC. WINFAC allows versatile analysis setup and instrument control for fluorescent intensity acquisition at fixed wavelengths or by synchronous scanning. Data is presented on screen, in real-time, and stored in text format. Reference analyses are performed at specified intervals and the coefficient of variation is continuously updated to monitor instrument performance. The automated system was validated against radioactive microspheres (RM) for lung perfusion in a pig and sheep and evaluated for analysis reproducibility. Fluorescent and radioactive microspheres were delivered by simultaneous injection into a femoral vein. Lungs were excised, flushed, dried at total lung capacity, and cubed into approximately 2cm(3) pieces (n=833 and 1560, pig and sheep, respectively). Radioactive count rates were determined for each lung piece (corrected for decay, background and spillover). Fluorescent dyes were extracted in solvent and intensities were determined at fixed wavelengths, using the automated spectrofluorimeter (corrected for background and spillover). Multi-color reference solutions were measured every 50 samples to monitor instrument reproducibility. Blood flow estimates for each piece determined by RM and FM methods were highly correlated: R(2)=0.98+/-0.017, Slopes=1.00+/-0.007 and Intercepts=0.00+/-0.006 (mean+/-SD). The CV of repeat reference analyses was 0.71%+/-0.16, a 30% to 50% reduction relative to manual analysis. Automated spectrofluorimetry reduces measurement errors and is a reliable and time saving advancement. With this technology, use of FM to measure regional lung perfusion approaches the ease and accuracy of the RM method.     

Galvanostatic cycling of vanadium oxide (V6O13) in a nonaqueous secondary lithium cell

The galvanostatic cycling of Li(Al)-V₆O₁₃ cells in 1M LiAsF₆/propylene carbonate (PC)-acetonitrile (AN) and 1M LiAsF₆/PC electrolytes is reported. The discharge capacity and voltage of the Li(Al)-V₆O₁₃ cell were shown to be consistently higher than those of the corresponding Li(Al)-TiS₂ cell. Discharge rates of 1.2, 2.5, 5.0 and 10.0 mA cm^?2 with active material utilisations of 20 – 60% were obtained from the Li(Al)-V₆O₁₃ cell. The addition of fresh PC-AN electrolyte resulted in an improvement in cell capacity, but did not stop capacity decline on cycling. Cycle life of Li(Al)-V₆O₁₃ cells was normally less than 50 cycles. It was also found that exposure of the V₆O₁₃ electrode to moist air reduced the OCV and the discharge capacity of the cell. Short circuiting and complete discharge of the cell resulted in lower capacity and this may have been due to some degree of irreversible reduction of the V₆O₁₃.     

Microwave fixation of brain tissue as a neurochemical technique- a review.

Microwave devices have been developed for rapidly inactivating brain enzymes by focusing the power output into the heads of small laboratory animals. The rapid inactivation achieved prevents postmortem changes and permits the measurement of neurochemicals such as acetylcholine at concentrations close to those obtained in vivo. The technique promises the assay of neurochemical parameters not possible before.     

Acute rigid gas permeable contact lens intolerance.

Rigid gas permeable (RGP) and polymethylmethacrylate (PMMA) lens wearers occasionally report episodes of acute intolerance which is experienced upon lens insertion. In this paper, we report two cases of such intolerance in which the probable cause was contact lens inversion. We also present the results of a study in which a custom-built calibrated strain gauge was used to measure the force in Newtons (N), required to invert RGP lenses [oxygen permeability, or Dk, values between 30 and 90 x 10(-11) (cm2/s) (mlO2/ml x mmHg)] and PMMA lenses of different spherical back vertex powers (+/-3.00 D, 9.00 D). Significantly, less force was required to invert minus powered lenses (17.5 +/- 4.8 N) than plus powered lenses (31.7 +/- 7 .4 N), irrespective of the material. PMMA lenses required more force to induce inversion than that required to invert RGP lenses. Lenses with a Dk of 90 required only two thirds of the force (20.0 +/- 5.8 N) required to cause inversion compared to PMMA lenses (32.9 +/- 11.0 N). High powered PMMA lenses were found to be more likely to fracture on inversion than any other lenses tested. The force required to return negatively powered lenses to their original shape, once inverted, was less than 25% of that initially required to induce inversion. Plus powered lenses either reverted to their original form spontaneously, or required less than 3% of the original inversion force to do so. It was concluded that practitioners should consider inversion as a possible reason for otherwise unexplained, acute RGP contact lens intolerance experienced upon lens insertion. The reason why inversion has eluded so many, as a possible cause of intolerance, is likely to be because minimal force is required to return those lenses, which do not crack or fracture, to their original shape.