Microfluidic quantum sensing platform for lab-on-a-chip applications

Lab-on-a-chip (LOC) applications have emerged as invaluable physical and life sciences tools. The advantages stem from advanced system miniaturization, thus, requiring far less sample volume while allowing for complex functionality, increased reproducibility, and high throughput. However, LOC applications necessitate extensive sensor miniaturization to leverage these inherent advantages fully. Atom-sized quantum sensors are highly promising to bridge this gap and have enabled measurements of temperature, electric and magnetic fields on the nano- to microscale. Nevertheless, the technical complexity of both disciplines has so far impeded an uncompromising combination of LOC systems and quantum sensors. Here, we present a fully integrated microfluidic platform for solid-state spin quantum sensors, like the nitrogen-vacancy (NV) center in diamond. Our platform fulfills all technical requirements, such as fast spin manipulation, enabling full quantum sensing capabilities, biocompatibility, and easy adaptability to arbitrary channel and chip geometries. To illustrate the vast potential of quantum sensors in LOC systems, we demonstrate various NV center-based sensing modalities for chemical analysis in our microfluidic platform, ranging from paramagnetic ion detection to high-resolution microscale NV-NMR. Consequently, our work opens the door for novel chemical analysis capabilities within LOC devices with applications in electrochemistry, high-throughput reaction screening, bioanalytics, organ-on-a-chip, or single-cell studies.

GlpC gene is responsible for biofilm formation and defense against phagocytes and imparts tolerance to pH and organic solvents in Proteus vulgaris

Biofilm-forming bacteria are highly resistant to antibiotics, host immune defenses, and other external conditions. The formation of biofilms plays a key role in colonization and infection. To explore the mechanism of biofilm formation, mutant strains of Proteus vulgaris XC 2 were generated by Tn5 random transposon insertion. Only one biofilm defective bacterial species was identified from among 500 mutants. Inactivation of the glpC gene coding an anaerobic glycerol-3-phosphate dehydrogenase subunit C was identified by sequence analysis of the biofilm defective strain. Differences were detected in the growth phenotypes of the wild-type and mutant strains under pH, antibiotic, and organic solvent stress conditions. Furthermore, we observed an increase in the phagocytosis of the biofilm defective strain by the mouse macrophage RAW264.7 cell line compared to the wild-type strain. This study shows that the glpC gene plays an important role in biofilm formation, in addition to imparting pH, organic solvent, and antibiotic tolerance, and defense against phagocytosis to Proteus sp. The results further clarified the mechanism of biofilm formation at the genomic level, and indicated the importance of the glpC gene in this process. This data may provide innovative therapeutic measures against P. vulgaris infections; furthermore, as an important crocodile pathogen, this study also has important significance in the protection of Chinese alligators.

Concentrations of cat and dust-mite allergens in dust samples from 92 large US office buildings from the BASE Study

The concentrations of cat (Fel d1) and dust-mite (Der f1 and Der p1) allergens were measured in 92 large office buildings in the US Environmental Protection Agency's Building Assessment Survey and Evaluation (BASE) Study (251 dust samples; one to four samples per building). Fel d1 was detected in almost all buildings and samples (91 buildings, 99%; 235 samples, 94%; range: <0.01-19 microg/g; median: 0.3 microg/g). Cat allergen exceeded 1 microg/g (a lower symptom threshold) in 56 samples (22%) from 45 buildings, but exceeded 8 microg/g (a sensitization threshold) in only two samples (1%) from two buildings. Der f1 or Der p1 was found in approximately half of all buildings and samples (63 and 70% of buildings; 45 and 51% of samples; range: <0.01-53 microg/g and <0.01-25 microg/g; median: <0.02 and 0.03 microg/g, respectively). Mite allergen exceeded 2 microg/g (a sensitization threshold) in seven samples (3%) from five buildings and exceeded 10 microg/g (a symptom threshold) in three samples (1%) from three buildings. Fel d1 concentration was significantly higher in samples collected in summer (June to September, 48 buildings), but cat allergen was not correlated with either mite allergen. Der f1, but not Der p1, concentration tended to be higher in samples collected in winter (December to April, 44 buildings), and the two mite allergens were significantly correlated only in winter. Cat and mite allergens were detected in 78% of representative US office buildings, but the concentrations seldom exceeded levels associated with sensitization or symptom provocation.

PRACTICAL IMPLICATIONS

The information on the concentrations of cat and dust-mite allergens in representative large US offices has expanded the baseline data available for interpretation of measurements from other building investigations. With suggested refinements, the BASE protocol for measurement of allergen concentrations in dust samples may serve as a guide to future studies of building characteristics, bioaerosol concentrations, and occupant perceptions of the indoor environment.

Impact of severe respiratory syndrome on anxiety levels of front-line health care workers

OBJECTIVE

To identify anxiety levels among front-line health care workers during the 2003 severe acute respiratory syndrome outbreak.

DESIGN

Questionnaire survey.

SETTING

Regional hospital, Hong Kong.

PARTICIPANTS

All hospital staff were given a questionnaire; administrative staff who had not had any patient contact served as controls.

MAIN OUTCOME MEASURES

Levels of contact with patients who had severe acute respiratory syndrome were measured and correlated with anxiety levels as determined by the State-Trait Anxiety Inventory.

RESULTS

Of 4252 questionnaires distributed between May and June 2003, 2040 (48.0%) were returned and 1926 (45.3%) were valid for analysis. Overall, 534 (27.7%) respondents had had contact with patients with severe acute respiratory syndrome. Anxiety scores ranged from 20 to 80, and mean (standard deviation) scores were higher among staff who had had contact with patients with severe acute respiratory syndrome than among those who had not (52.6 [10.5] versus 49.8 [10.1], respectively; P<0.01). Mean anxiety levels were higher among workmen, health care assistants, and nurses than among administrative staff controls or doctors (P<0.01). Anxiety scores were correlated with burnout scores (Pearson's correlation coefficient, 0.52-0.59) and with discomfort from wearing protective gear (0.21-0.32).

CONCLUSION

Severe acute respiratory syndrome has likely stressed the public health care system. Prediction and early identification of adverse factors in a crisis situation would allow early implementation of interventions to reduce and counteract the impact of this stress.

Antinociceptive effect of a novel long-acting nalbuphine preparation †

BACKGROUND

A long-acting analgesic may be particularly desirable in patients suffering from long-lasting pain. The aim of the study was to evaluate the antinociceptive effect of a novel nalbuphine preparation and to determine its duration of action.

METHODS

The antinociceptive effects of i.m. nalbuphine HCl in saline and nalbuphine base in sesame oil were evaluated in rats. The in vitro drug-releasing profiles of nalbuphine HCl and base in different preparations were also evaluated.

RESULTS

We found that i.m. nalbuphine HCl 25, 50 and 100 micromol kg(-1) produced dose-related antinociceptive effects with a duration of action of 1.5, 2 and 3 h, respectively. i.m. nalbuphine base 100, 200 and 400 micromol kg(-1) also produced dose-related antinociceptive effects but with longer durations of action: 27, 49 and 55 h, respectively. In vitro studies demonstrated that nalbuphine base in sesame oil had the slowest drug-releasing profile of the different preparations.

CONCLUSIONS

i.m. injection of an oil formulation of nalbuphine base produced a long-lasting antinociceptive effect.

Physiognomy and teeth: an ethnographic study among young and middle-aged Hong Kong adults

OBJECTIVES

To determine knowledge and beliefs about traditional physiognomy (judging an individual's character from their facial appearance) concerning teeth among young (17-26) and middle-aged (35-44) Hong Kong adults.

METHODS

In a cross sectional ethnographical telephone survey, 400 adults were interviewed about 16 traditional physiognomy concerning teeth (in consultation with a Feng Shui specialist).

RESULTS

Most completed the interview (93%, 373). Over half the study group (63%, 234) claimed they had heard of aspects of physiognomy concerning teeth, and a quarter (24%, 88) believed in such ideologies. Variations in knowledge and beliefs were apparent among people of different age (P < 0.01), gender (P < 0.05), educational attainment (P < 0.01), economic status (P < 0.01), place of birth (P < 0.01) and religion (P < 0.01). Their knowledge and belief in aspects of physiognomy concerning teeth was also associated with reported use of dental services (P < 0.01).

CONCLUSION

Among young and middle-aged adults in Hong Kong, knowledge and beliefs concerning traditional physiognomy regarding teeth is strong, and socio-demographic variations exist in these perceptions. These findings have implications for all those involved in the delivery of dental care in multicultural societies and in raising cultural awareness about traditional health beliefs.

The zebrafish space cadet gene controls axonal pathfinding of neurons that modulate fast turning movements

All vertebrates depend on neural circuits to produce propulsive movements; however, the contribution of individual neural cell types to control such movements are not well understood. We report that zebrafish space cadet mutant larvae fail to initiate fast turning movements properly, and we show that this motor phenotype correlates with axonal defects in a small population of commissural hindbrain neurons, which we identify as spiral fiber neurons. Moreover, we demonstrate that severing spiral fiber axons produces space cadet-like locomotor defects, thereby providing compelling evidence that the space cadet gene plays an essential role in integrating these neurons into the circuitry that modulates fast turning movements. Finally, we show that axonal defects are restricted to a small set of commissural trajectories, including retinal ganglion cell axons and spiral fiber axons, and that the space cadet gene functions in axonal pathfinding. Together, our results provide a rare example in vertebrates of an individual neuronal cell type that contributes to the expression of a defined motor behavior.

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Multiple actinomyces brain abscesses: case report

A case of multiple cerebral abscesses caused by actinomyces is reported in a 37 year old male with mucoepidermoid carcinoma of the right lung. In conjunction with penicillin, sulfonamide and erythromycin, the patient underwent stereotactic surgery for aspiration of the brain abscesses under (CT). The bacteria, considered to originate from the right lung, were identified from the abscess material obtained at surgery. Using proper therapy to control infection and intracranial pressure is important. A lon g term follow up with frequent computerised tomography evaluation has been conducted and the patient outcome has been successful recovery.

A survey of environmental tobacco smoke controls in California office buildings

A survey of environmental tobacco smoke (ETS) controls in California office buildings was carried out to obtain information of the type and distribution of ETS controls in office buildings and to evaluate the effectiveness of various ETS controls. A total of 118 smoking areas in 111 county and city buildings were inspected to collect information on the type of ETS controls. Only 31% of the smoking areas inspected were physically separated from nonsmoking areas with full floor-to-true-ceiling walls, 25% exhausted air to the outside, and 38% did not recirculate air to non-smoking areas. A total of 23 smoking areas and their adjacent non-smoking areas in 21 buildings were monitored for nicotine and fluorescent particulate matter (FPM). A tracer gas, sulfur hexafluoride (SF6), was released in smoking areas to measure the air leakage from smoking areas to adjacent non-smoking areas. The measurements of nicotine, FPM, and SF6 have shown large variations of the effectiveness of ETS controls. The least effective type of smoking area studied were open areas with no physical barriers between smoking and nonsmoking areas, no exhaust to the outside and no return air separation. On the contrary, smoking rooms with three ETS controls (i.e., physical separation, exhaust to outside, and no air recirculation) were the most effective design in containing ETS within smoking areas.

Unintentional carbon monoxide deaths in California from residential and other nonvehicular sources

To investigate risk factors of unintentional carbon monoxide deaths in California from nonvehicular sources, we identified 270 deaths resulting from nonvehicular sources of carbon monoxide poisoning from death certificates and coroners' investigation reports. Data recorded between 1979 and 1988 in the state of California on risk factors and carbon monoxide sources were abstracted from investigation reports. We also used census and state statistics to calculate rates and relative risks. The highest rates, which occurred in winter, were found among males, African Americans, and the elderly. Relative risks (in parentheses) were higher among individuals who (a) lived in multiunit dwellings (2.1), (b) dwelled in mobile/trailer homes (4.7), and (c) resided in temporary shelters (30.0) than among individuals who lived in single-family houses (1.0). Unvented combustion heating appliances and charcoal fuel were associated significantly with the risks of fatal unintentional carbon monoxide poisoning.

Comparative efficacy of 24-hour and 16-hour transdermal nicotine patches for relief of morning craving

AIMS

To compare a transdermal nicotine patch designed for 24-hour wear with one designed for 16-hour wear for relief of craving and withdrawal, particularly in the morning hours.

DESIGN

Smokers were randomly assigned to use one of two common patch regimens: NicoDerm/NiQuitin (24-hour wear, 21 mg nicotine) or Nicotrol/Nicorette (16-hour wear, 15 mg). In a double-dummy design, participants wore two patches during the day, one active, one placebo and one patch while sleeping.

SETTING

A smoking cessation research clinic.

PARTICIPANTS

Two hundred and forty-four smokers who suffered morning cravings.

INTERVENTION

Two patch formulations approved and marketed for over-the-counter use in the US--NicoDerm CQ (labeled as 21 mg over 24 hours) and Nicotrol (labeled as 15 mg over 16 hours)--were each used according to its instructions. Smokers also received behavioral counseling.

MEASUREMENTS

For a week of baseline and 2 weeks after quitting, smokers used palm-top computers to assess craving and withdrawal symptoms several times each day.

FINDINGS

The 21 mg/24-hour patch yielded consistently better control of craving, not only during the morning hours, but throughout the day, and over the 2-week period of abstinence. Additionally, the 21 mg/24-hour patch yielded greater reductions in anxiety, irritability and restlessness. Smokers using the 21 mg/24-hour dosing regimen also experienced longer abstinence than those using the 15 mg/16-hour patch.

CONCLUSIONS

These findings demonstrate that 24-hour dosing with a 21 mg patch affords superior relief of craving and withdrawal during the first 2 weeks of abstinence, when symptoms are at their peak, and when relapse is most likely. They confirm the importance of dosing parameters in nicotine replacement products.

Dynamic effects of self-efficacy on smoking lapse and relapse

Self-efficacy (SE) is thought to be critical to success in smoking cessation both as an individual difference and as a dynamic process after a quit attempt. In this study, 214 smokers used palm-top computers to record day-to-day variations in SE during 4 weeks after quitting. SE remained at high and stable levels prior to a 1st lapse but decreased and became more variable thereafter. The authors used event history models with time-varying covariates to assess the effect of daily SE on lapse and relapse risk. Daily SE measures predicted an initial lapse on the subsequent day. However, this relationship was accounted for by stable baseline differences in SE (assessed by questionnaire), rather than by day-to-day dynamics in SE. Progression from 1st lapse to relapse was also examined. In this instance, daily SE predicted subsequent relapse risk, even when baseline SE and concurrent smoking were accounted for, suggesting the importance of SE dynamics for this stage of the relapse process.

Laser ablations reveal functional relationships of segmental hindbrain neurons in zebrafish

Segmentation of the vertebrate brain is most obvious in the hindbrain, where successive segments contain repeated neuronal types. One such set of three repeated reticulospinal neurons--the Mauthner cell, MiD2cm, and MiD3cm--is thought to produce different forms of the escape response that fish use to avoid predators. We used laser ablations in larval zebrafish to test the hypothesis that these segmental hindbrain cells form a functional group. Killing all three cells eliminated short-latency, high-performance escape responses to both head- and tail-directed stimuli. Killing just the Mauthner cell affected escapes from tail-directed but not from head-directed stimuli. These results reveal the contributions of one set of reticulospinal neurons to behavior and support the idea that serially repeated hindbrain neurons form functional groups.

Intent-to-treat analysis for longitudinal clinical trials: coping with the challenge of missing values

Drop-out is a common phenomenon in clinical trials of drug treatments involving longitudinal assessments for a fixed duration of follow-up. For these trials intent-to-treat (IT) analysis is usually preferred because time effects are seen in practice. The IT analysis mandates that all subjects randomized to a treatment arm should be included in the analysis. The purpose of the present paper is to acquaint both clinicians and statisticians with recent statistical methodological advances in handling drop-outs and their usage for IT analysis. We discuss a sensitivity analysis of 12-month outcome data to investigate the efficacy of drug therapy from a longitudinal double-blind placebo-controlled clinical trial in the maintenance therapy of geriatric major depressive illness. Outcome measures consist of monthly Hamilton depression scores. The sensitivity analysis includes endpoint analysis, last observation carried forward analysis, repeated measures models and imputation models. Imputation models are based on multiple imputations of missing responses deriving from an 'as-treated' model. The model used imputed doses from a plausible treatment scenario after drop-out and a 'propensity-adjusted' model where the imputations for the drop-outs were obtained from the adhering subjects with the same probability to remain on study (propensity) given the observed trajectory prior to withdrawal. Issues related to bias and efficiency of the estimates obtained by different analyses are discussed. We recommend a more widespread use of imputation models for the IT analysis.

Unintentional carbon monoxide deaths in California from charcoal grills and hibachis

This study was carried out to determine the annual incidence rate of and factors associated with unintentional deaths due to carbon monoxide (CO) poisoning from charcoal grills/hibachis in California during 1979-1988. A search through the California Master Mortality File was conducted to identify all cases with ICD-9 codes related to unintentional CO deaths. Individual coroners' investigation reports were obtained from 42 counties and evaluated by three evaluators. After excluding miscoded and misclassified cases, 444 deaths were judged to be authentic cases of unintentional CO poisoning. Among them, 59 deaths found to be due to the improper use of charcoal grills/hibachis. An increasing but not statistically significant trend was observed over the 10-year period. The highest rates occurred among males, asians, blacks, and middle-aged (20-39) people. Fifty-four percent of the deaths occurred in motor vehicles and 46% in residential structures.

Zebrafish as a model system for studying neuronal circuits and behavior

Zebrafish are best known as a model system for studies of the genetics of development. They do, however, also offer many advantages for the study of neuronal circuitry because the larvae are transparent, allowing optical studies of neuronal activity and noninvasive photoablations of individual neurons. The combination of these optical methods with genetics through the use of mutant and transgenic lines of fish should make the zebrafish model a unique and powerful one among vertebrates. Here we review the strengths of the model and the possibilities it offers for studies of the neural basis of behavior.

Identification and case management in an HMO of patients at risk of preterm labor

We carried out a study of pregnant patients in a health maintenance organization to identify and provide case management of women at risk of preterm labor and to determine important risk factors for preterm labor in a managed care population. Data were collected on 794 women who completed an initial prenatal care visit at HealthAmerica of Pittsburgh between July 15, 1994, and March 31, 1995, and delivered at a local Pittsburgh hospital. The patients were assessed during an initial call to schedule their first prenatal visit and also at the 8- to 15-week and 24- to 28-week prenatal visits. Patients scoring 10 or higher on the risk assessment form were referred to a nurse case manager who provided education and support. Results of a logistic regression analysis suggest that the risk assessment tool was effective in identifying women at risk for preterm labor. "Physical/stressful work", as assessed by the patient, history of a prior preterm birth, and multiple gestation were all statistically significant predictors of preterm birth. Further research is needed to confirm the finding that physical or stressful work is a significant predictor of preterm births and to determine which aspects of the work may increase the patient's risk. This study was based on 8 months of data; however, additional program implementation is needed to evaluate fully the potential long-term benefits of the program.

Causes of unintentional deaths from carbon monoxide poisonings in California

The purpose of this study was to determine the annual number and incidence of unintentional deaths from carbon monoxide (CO) poisonings in California and to identify specific factors that caused or contributed to the deaths. Unintentional CO deaths in California over a ten-year period (1979 to 1988) were identified from the database of the California Master Mortality File and coroners' investigation reports. Factors associated with unintentional CO deaths were determined based on the information from the investigation reports. The annual number of unintentional CO deaths varied from 27 to 58 over the ten years examined, with an average annual death incidence of 1.7 x 10(-6). Death rates were high among males and African-Americans. Alcohol appeared to be a factor in 31% of the cases. The types of combustion sources associated with unintentional CO deaths were: heating or cooking appliances; motor vehicles; charcoal grills and hibachis; small engines; and camping equipment. Factors associated with unintentional CO deaths interact in a complex way. To reduce the rate of unintentional CO deaths effectively, joint efforts involving several prevention methods are suggested.

Dependence of myocardial hypothermia tolerance on sources of activator calcium

To determine the relationship between cardiac hypothermia tolerance and the sources of activator calcium, we selectively modified either the sarcolemmal calcium permeability by nifedipine or the sarcoplasmic reticulum function by caffeine in papillary muscles from both the rat, as a cold sensitive model, and the ground squirrel, Citellus dauricus, a deep hibernator. Both force-interval relationship and cooling performance were investigated. At 25 degrees C, the slope of the force-interval curve of the ground squirrel was nearly double that of the rat. At shorter test intervals 0.5 muM nifedipine moved the curve down with little effect at longer intervals, and the curve slope increased. Caffeine (1 mM) decreased the peak force and eliminated its dependence upon test interval. When the temperature was lowered, rat preparations showed a marked increase of resting tension and aftercontraction between 7 and 12 degrees C and became inexcitable. In contrast, they maintained contractility down to a few degrees above 0 degrees C without aftercontraction and increased resting tension in the ground squirrel. In the rat nifedipine shortened the contractions, prevented the increase of resting tension, and minimized aftercontractions, with little improvement of contractility. Caffeine prolonged the contractions, caused a striking increase of resting tension and aftercontractions, and finally disabled the contractility at about 5-10 degrees C, even in the ground squirrel. We conclude that depressed calcium influx helps to prevent hypothermic calcium overload of the cardiac cells. Good function of the sarcoplasmic reticulum is essential for tolerance of hypothermia by cardiac cells. A suggestion that may improve the hypothermic tolerance of the myocardium from nonhibernators is postulated.

Relation between residential radon concentrations and housing characteristics. The Cracow Study

The survey on indoor radon exposure was undertaken to explain whether the excess in lung cancer deaths in Cracow city center may be attributed to this particular exposure. A total of 310 detectors was placed in households randomly chosen from three homogenous strata of residential buildings. The first stratum included house in the old city center constructed predominantly out of the stone bricks. The second stratum covered area of the city with big apartment condominiums built out of concrete blocks. The third stratum consisted of single family houses located in a suburban area. From each of these residency strata a random sample of equal number of households has been chosen and the radon detectors were placed in households located at different levels of buildings. The three-month radon sampling data were used to determine the distribution of various levels of radon in the households. In the measurement of radon exposure the Landauer alpha-track samplers were used. The data collected show that the best single predictor of indoor radon concentrations was type of building. Other variables found to be associated significantly with indoor concentrations were household level in the building and house age. In general, residences with a concrete slabs and dwellings with rarely-opened windows were found to have slightly higher radon concentrations.

Participation of the protein Go in multiple aspects of behavior in C. elegans

The goa-1 gene encoding the alpha subunit of the heterotrimeric guanosine triphosphate-binding protein (G protein) Go from Caenorhabditis elegans is expressed in most neurons, and in the muscles involved in egg laying and male mating. Reduction-of-function mutations in goa-1 caused a variety of behavioral defects including hyperactive movement, premature egg laying, and male impotence. Expression of the activated Go alpha subunit (G alpha o) in transgenic nematodes resulted in lethargic movement, delayed egg laying, and reduced mating efficiency. Induced expression of activated G alpha o in adults was sufficient to cause these phenotypes, indicating that G alpha o mediates behavior through its role in neuronal function and the functioning of specialized muscles.

Sensory regulation of male mating behavior in Caenorhabditis elegans

C. elegans male mating behavior comprises a series of steps: response to contact with the hermaphrodite, backing along her body, turning around her head or tail, location of the vulva, insertion of the two copulatory spicules into the vulva, and sperm transfer. By ablation of male-specific copulatory structures and their associated neurons, we have identified sensory structures and neurons that participate in each of these steps: the sensory rays mediate response to contact and turning; the hook, the postcloacal sensilla, and the spicules mediate vulva location; the spicules also mediate spicule insertion and regulate sperm transfer. Generally, successful completion of each step places the male in a position to receive a cue for the next step in the pathway. However, the high degree of sensory regulation allows the male to execute some steps independently.

Correlation between meteorological conditions and mutagenicity of airborne particulate samples in a tropical monsoon climate area from Kaohsiung City, Taiwan

Kaohsiung is a city of 1.5 million located in the southern part of Taiwan. It has a serious air pollution problem mainly attributable to much industrial and commercial activity. In order to estimate the effects of traffic, season, and meteorological conditions on the mutagenicity of Kaohsiung City's urban ambient particulate matter, 624 airborne particulate samples were collected on a weekly basis from 12 locations for an entire year. The mutagenic potential of acetone extracts of air samples was evaluated by the Salmonella/microsomal test with S. typhimurium TA98 in the presence and absence of S9 mixtures. The air samples from November 1990 showed the highest direct and indirect mutagenicity among the 12 months, whereas those from June and July 1991 had the lowest direct and indirect mutagenic activity, respectively. The mutagenicity showed a good correlation with amounts of the acetone extractable matter of airborne particulates. The meteorological conditions, monthly mean precipitation, and wind speed also showed a good correspondence with mutagenicity. Wind direction and temperature had a moderate relationship. The major mutagenic fractions of air samples that had the highest mutagenic activity in a month were purified using Sephadex LH-20 column chromatography, and the contents of PAHs, 1-NP, and DNPs were analyzed by HPLC. The characteristic concentration ratios of PAHs indicated that, for the main pollution sources of airborne particulates from Kaohsiung city, the mobile sources were more important than the stationary ones. The total amounts of 1-NP and DNPs in airborne particulates seemed to correspond to their mutagenicity. Although the total amounts of 1-NP and DNPs in the air samples correlated with their mutagenicity, the major mutagenic chemicals in the airborne particulate samples from Kaohsiung City need further investigation.

The distribution of lifetime cumulative exposures to radon for California residents

The distribution of individual lifetime exposures to radon was estimated using data from studies on radon concentrations, mobility, and time-activity patterns in the state of California. The distributions of radon concentrations in various geographic regions were obtained from the results of year-long radon measurements of 310 residences. The mobility patterns were acquired through a survey of the moving histories of the members of 507 households. The indoor and outdoor time-activity data were collected for 1,780 individuals in 1,596 households. Based on these data, a computer simulation technique was used to estimate the distribution of radon exposures with a parametric (lognormal model) and a nonparametric approach (bootstrap method). The estimated average lifetime exposure for radon was 2,448 Bq.m-3.yr for the lognormal model and 2,487 Bq.m-3.yr for the bootstrap method. The standard deviation was 1,130 and 1,145 Bq.m-3.yr respectively. Assuming no move over the lifetime, the estimated average lifetime exposure to radon was 2,052 Bq.m-3.yr for the lognormal model and 2,078 Bq.m-3.yr for the bootstrap method, while the standard deviation increased to 1,378 Bq.m-3.yr for the lognormal model and 1,514 Bq.m-3.yr for the bootstrap method.

Irritant effects of formaldehyde exposure in mobile homes

This paper reports the irritant effects associated with formaldehyde exposures in mobile homes. Week-long, integrated formaldehyde concentrations were measured using passive monitors in summer and winter while the mobile home residents continued their normal activities. Information on acute health problems, chronic respiratory/allergic illnesses, smoking behavior, demographic variables, and time spent at home was obtained on over 1000 individuals during the sampling period. Measured formaldehyde concentrations varied from under the limit of detection (0.01 ppm) to 0.46 ppm. Formaldehyde exposure was estimated for each individual by multiplying the concentration measured in his or her home by the time he or she spent at home. Irritant effects were found to be associated with formaldehyde exposure after controlling for age, sex, smoking status, and chronic illnesses using a logistic procedure. Some of the interaction terms found to be significant indicated that there were synergistic effects between formaldehyde exposure and chronic health problems.

Radon in California homes

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Trypsin inhibition assay as related to limited hydrolysis of inhibitors

In the assay of two soybean trypsin inhibitors, the Kunitz and the Bowman-Birk inhibitors, two procedures were used: the current procedure in which the substrate is added last (the S-last test), after inhibitor is mixed with enzyme, and a new procedure in which the enzyme is added last (the E-last test), after inhibitor is mixed with substrate. In the E-last test, the inhibition values obtained were independent of the premix pH and preincubation time, while in the S-last test, the values were functions of these two parameters. When the pH was below 2.7 or near neutrality, the values of S-last test were equal to those of the E-last test. When the pH was 2.7-5.5 or 7.5-9.0, the S-last values were lower than the E-last values. This so-called "reactant sequence effect" is attributed to limited hydrolysis of the inhibitor at these pH ranges, in accordance with the reactive site model proposed by K. Ozawa and M. Laskowski, Jr. (1966, J. Biol. Chem. 241, 3955). When the premix pH was jumped from the acidic or alkaline ranges to near neutral, the reactant sequence effect was abolished, indicating resynthesis of the inhibitor from the modified one. Results of this study show that the E-last test is preferable to the S-last test for assaying a trypsin inhibitor of protein nature.

Insulin-related genes expressed in human placenta from normal and diabetic pregnancies

Rapid growth of human fetal tissues requires insulin or insulin-like growth factors. A high rate of human fetal growth occurs between implantation and about 14 weeks of gestation. Fetal pancreatic insulin secretion begins much later. Since maternal insulin does not cross the blood/placental barrier, other sources of insulin or insulin-like growth factors may be provided for fetal development. We report here that placental polyadenylylated RNAs from the first and third trimester of normal pregnancy as well as from term pregnancies of diabetic mothers hybridize to a 32P-labeled cloned cDNA of an insulin-related sequence expressed in fetal pancreas. Moreover, placentas from diabetic women express much more of these sequences. These results suggest that insulin-related genes are expressed in placental tissue during fetal development and may be a source of growth-promoting hormones for the human fetus. Fetuses developing in diabetic women receive a large influx of glucose. This in turn may stimulate the expression of insulin-related sequences, which may result in higher utilization of glucose, thus bringing about the macrosomia and high incidence of malformation and still-births known to result from pregnancies in diabetics.

Onset symptoms as predictors of mortality and disability in multiple sclerosis

941 cases of definite/probable multiple sclerosis living in Los Angeles County, California and King and Pierce Counties, Washington in 1970 who had onset between 1960 and 1969 were followed for mortality and disability through 1980. Early age of onset and residence in Washington State were predictors of less rapid and severe subsequent course. Coordination symptoms at onset were prognostic of rapid progression to disability and/or early death, whereas early motor weakness was significantly predictive only for disability. The presence of sensory symptoms in addition to motor and/or coordination symptoms at onset, however, indicated a better prognosis than coordination and/or motor symptoms alone. This observation and the results of regression analyses indicated that specific groupings of symptoms at onset were more important for predicting course than the number of symptoms present at onset.