[Radiation exposure in (90)Y-Zevalin therapy: results of a prospective multicentre trial]

AIM of this study was the assessment of the radiation exposure from preparation and application of (90)Y-Zevalin, the measurement of the dose rate at the patient, the exposure of family members as well as the determination of the activity concentration in urine of patients. METHODS: Overall data from 31 therapeutic administrations carried out in four institutions were evaluated. During preparation and application of (90)Y-Zevalin the finger exposures of radiochemists, technicians, and physicians were measured. The dose rate of the patient was measured immediately after radioimmunotherapy. In patients treated in a nuclear medicine therapy unit, urine was collected over a two day period and the corresponding activity was determined. Family members of outpatients were asked to wear a dosimeter over a seven day period. RESULTS: During the preparation we found a maximum skin dose of 6 mSv at the average, and during application of 3 mSv, respectively. After administration of (90)Y the dose rate was 0.4 +/- 0.1 microSv/h at 2 m distance. Urine measurements yielded a cumulated 24 h excretion of 3.9 +/- 1.4% and 4.4 +/- 1.4% within 48 h, respectively, that is equivalent to 43 +/- 18 and 50 +/- 20 MBq of (90)Y, respectively. Family members received a radiation exposure of 40 +/- 14 microSv over seven days. CONCLUSION: During preparation and application of (90)Y-Zevalin appropriate radiation shielding is necessary. For family members as well as nursing staff no additional special radiation protection measures beyond those being common for other nuclear medicine procedures are necessary.

Effects of fixed night shift work on 24 hour blood pressure regulation, state anxiety levels and total sleep time

Nearly 22 million Americans operate as shift workers, and shift work has been linked to the development of cardiovascular disease (CVD). This study is aimed at identifying pivotal risk factors of CVD by assessing 24 hour ambulatory blood pressure, state anxiety levels and sleep patterns in 12 hour fixed shift workers. We hypothesized that night shift work would negatively affect blood pressure regulation, anxiety levels and sleep patterns. A total of 28 subjects (ages 22-60) were divided into two groups: 12 hour fixed night shift workers (n=15) and 12 hour fixed day shift workers (n=13). 24 hour ambulatory blood pressure measurements (Space Labs 90207) were taken twice: once during a regular work day and once on a non-work day. State anxiety levels were assessed on both test days using the Speilberger’s State Trait Anxiety Inventory. Total sleep time (TST) was determined using self recorded sleep diary. Night shift workers demonstrated increases in 24 hour systolic (122 ± 2 to 126 ± 2 mmHg, P=0.012); diastolic (75 ± 1 to 79 ± 2 mmHg, P=0.001); and mean arterial pressures (90 ± 2 to 94 ± 2mmHg, P<0.001) during work days compared to off days. In contrast, 24 hour blood pressures were similar during work and off days in day shift workers. Night shift workers reported less TST on work days versus off days (345 ± 16 vs. 552 ± 30 min; P<0.001), whereas day shift workers reported similar TST during work and off days (475 ± 16 minutes to 437 ± 20 minutes; P=0.231). State anxiety scores did not differ between the groups or testing days (time*group interaction P=0.248), suggesting increased 24 hour blood pressure during night shift work is related to decreased TST, not short term anxiety. Our findings suggest that fixed night shift work causes disruption of the normal sleep-wake cycle negatively affecting acute blood pressure regulation, which may increase the long-term risk for CVD.

The role of cardiorespiratory fitness and weight status on 24-hr ambulatory blood pressure among adolescents

BACKGROUND: This observational research study investigated the association of cardiorespiratory fitness and weight status with repeated measures of 24-hr ambulatory blood pressure (24-hr ABP). Little is known about these associations and few data exist examining the interaction between cardiorespiratory fitness and weight status and the contributions of each on 24-hr ABP in youth. ^ METHODS: This research study used secondary analysis data from the "Adolescent Blood Pressure and Anger: Ethnic Differences" study. This current study sample included 374 African-American, Anglo-American, and Mexican-American adolescents 11-16 years of age. Mixed-effects models were used for testing the relationship between weight status and cardiorespiratory fitness and repeated measures of ambulatory blood pressure over 24 hours (24-hr ABP). Weight status was categorized into "normal weight" (BMI<85th percentile), "overweight" (85th≤BMI<95th), and "obese" (BMI≥95th). Cardiorespiratory fitness, determined by heart rate recovery (HRR), was defined as the difference between heart rate at peak exercise and heart rate at two minutes post-exercise, as measured by a height-adjusted step test and stratified into two groups: low and high fitness, using a median split. Ambulatory blood pressure (ABP) was monitored for a 24-hr period on a school day using the Spacelabs ambulatory monitor (Model 90207). Blood pressure and heart rate were recorded at 30 minute intervals throughout the day of recording and at 60 minute intervals during sleep. ^ RESULTS: No significant associations were found between weight status and mean 24-hr systolic blood pressure (SBP) or mean arterial pressure (MAP). A significant and inverse association between weight status and mean 24-hr diastolic blood pressure (DBP) was revealed. Cardiorespiratory fitness was significantly and inversely associated with mean 24-hr ABP. High fitness adolescents had significantly lower mean 24-hr SPB, DBP, and MAP measurements than low fitness adolescents. Compared to low fitness adolescents, high fitness adolescents had 1.90 mmHg, 1.16 mmHg, and 1.68 mmHg lower mean 24-hr SBP, DBP, and MAP, respectively. Additionally, high fitness appeared to afford protection from higher mean 24-hr SBP and MAP, irrespective of weight status. Among normal weight adolescents, low fitness resulted in higher mean 24-hr SBP and MAP, compared to their fit counterparts. Among adolescents categorized as high fitness, increasing weight status did not appear to result in higher mean 24-hr SBP or MAP. Cardiorespiratory fitness, rather than weight status, appeared to be a more dominant predictor of mean 24-hr SBP and MAP. ^ CONCLUSIONS: To our knowledge, this research is the first study to investigate the independent and combined contributions of cardiorespiratory fitness and weight status on 24-hr ABP, all objectively measured. The results of this study may potentially guide and inform future research. It appears that early cardiovascular disease (CVD) prevention should focus on improving cardiorespiratory fitness levels among all adolescents, particularly those adolescents least fit, regardless of their weight status, while obesity prevention efforts continue.^

Chamber evaluation of a personal organic vapor dosimeter at ppb concentrations of VOCs, varying temperatures and humidities with 24 -hour exposures

An exposure system was constructed to evaluate the performance of a personal organic vapor dosimeter (3520 OVM) at ppb concentrations of nine selected target volatile organic compounds (VOCs). These concentration levels are generally encountered in community air environments, both indoor and outdoor. It was demonstrated that the chamber system could provide closely-controlled conditions of VOC concentrations, temperature and relative humidity (RH) required for the experiments. The target experimental conditions included combinations of three VOC concentrations (10, 20 and 200 $\rm\mu g/m\sp3),$ three temperatures (10, 25 and 40$\sp\circ$C) and three RHs (12, 50 and 90% RH), leading to a total of 27 exposure conditions. No backgrounds of target VOCs were found in the exposure chamber system. In the exposure chamber, the variation of the temperature was controlled within $\pm$1$\sp\circ$C, and the variation of RH was controlled within $\pm$1.5% at 12% RH, $\pm$2% at 50% RH and $\pm$3% at 90% RH. High-emission permeation tubes were utilized to generate the target VOCs. Various patterns of the permeation rates were observed over time. The lifetimes and permeation rates of the tubes differed by compound, length of the tube and manufacturer. By carefully selecting the source and length of the tubes, and closely monitoring tube weight loss over time, the permeation tubes can be used for delivering low and stable concentrations of VOCs during multiple days.^ The results of this study indicate that the performance of the 3520 OVM is compound-specific and depends on concentration, temperature and humidity. With the exception of 1,3-butadiene under most conditions, and styrene and methylene chloride at very high relative humidities, recoveries were generally within $\pm$25% of theory, indicating that the 3520 OVM can be effectively used over the range of concentrations and environmental conditions tested with a 24-hour sampling period. Increasing humidities resulted in increasing negative bias from full recovery. Reverse diffusion conducted at 200 $\rm\mu g/m\sp3$ and five temperature/humidity combinations indicated severe diffusion losses only for 1,3-butadiene, methylene chloride and styrene under increased humidity. Overall, the results of this study do not support the need to employ diffusion samplers with backup sections for the exposure conditions tested. ^

Strontium isotopic composition and chronology of sediments from DSDP Site 90-588

We report 261 strontium isotopic analyses of well-preserved planktonic foraminifers from three Deep Sea Drilling Project Sites (519, 588, and 607). These samples cover the period from 24 Ma to present with an average of approximately one sample per 100 ka. The combination of high sample density and uniformity of analytical procedures has produced a well-defined record of changes in the 87Sr/86Sr of seawater during the Neogene. The record can be viewed as a series of essentially linear segments with slopes ranging from as high as 0.00006/m.y. to as low as 0/m.y. The times associated with major inflections in the curve do not appear to correspond to simple geologic phenomena such as eustatic cycles, but are probably controlled by a combination of tectonic and climatic factors that influenced the abundance and isotopic composition of terrestrial strontium input to the oceans. The strontium isotopic data are consistent with a progressive increase in the chemical weathering rates of the continents during the Neogene, probably related to repeated glaciations, increased exposure of continents by lowered sea level, and increased continental relief resulting from high rates of tectonic uplift.

Quaternary isotope stratigraphy of DSDP Hole 90-593 from the Challenegr Plateau, South Tasman Sea

A moderate-resolution isotope stratigraphy (with an average of one sample per 17,500 yr.) derived from the benthic foraminifer Uvigerina (or Cibicides), the planktonic foraminifer Globigerina bulloides, and calcareous nannofossil concentrates is presented for the entire Quaternary (and latest Pliocene) section of mid-upper bathyal calcareous oozes from DSDP Site 593, western Challenger Plateau, south Tasman Sea. Superimposed on a trend of gradually increasing average delta18O values through the Pleistocene, reflecting the progressive buildup of polar ice sheets, is a record of highfrequency but generally low amplitude (0.5-1?) isotope fluctuations in the early Quaternary (1.9-1.0 m.y.), followed by a greatly increased intensity (1.5-2.0 ?) of glacial-interglacial fluctuations during the late Quaternary (< 1.0 m.y.). The standard late Quaternary isotope stages 1 to 24 are mainly resolvable. Significant excursions in both delta18O and delta13C values at various times during the Quaternary are suggested to be due to periodic, fundamental changes in ocean circulation properties over the plateau. For example, intensified upwelling of Antarctic Intermediate Waters during several glacial periods is indicated by the convergence of benthic and planktonic foraminiferal delta18O data, and productivity variations may account for certain delta13C spikes in the record. With increasingly higher resolution analysis this core will provide a useful Quaternary isotope reference section for southern temperate waters in the southwest Pacific, centered on New Zealand.