Clinical Phenotypes of Sepsis in a Cohort of Hospitalized Patients According to Infection Site

OBJECTIVES

Clinical sepsis phenotypes may be defined by a wide range of characteristics such as site of infection, organ dysfunction patterns, laboratory values, and demographics. There is a paucity of literature regarding the impact of site of infection on the timing and pattern of clinical sepsis markers. This study hypothesizes that important phenotypic variation in clinical markers and outcomes of sepsis exists when stratified by infection site.

DESIGN

Retrospective cohort study.

SETTING

Five hospitals within the Wake Forest Health System from June 2019 to December 2019.

PATIENTS

Six thousand seven hundred fifty-three hospitalized adults with a discharge International Classification of Diseases, 10th Revision code for acute infection who met systemic inflammatory response syndrome (SIRS), quick Sepsis-related Organ Failure Assessment (qSOFA), or Sequential Organ Failure Assessment (SOFA) criteria during the index hospitalization.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome of interest was a composite of 30-day mortality or shock. Infection site was determined by a two-reviewer process. Significant demographic, vital sign, and laboratory result differences were seen across all infection sites. For the composite outcome of shock or 30-day mortality, unknown or unspecified infections had the highest proportion (21.34%) and CNS infections had the lowest proportion (8.11%). Respiratory, vascular, and unknown or unspecified infection sites showed a significantly increased adjusted and unadjusted odds of the composite outcome as compared with the other infection sites except CNS. Hospital time prior to SIRS positivity was shortest in unknown or unspecified infections at a median of 0.88 hours (interquartile range [IQR], 0.22-5.05 hr), and hospital time prior to qSOFA and SOFA positivity was shortest in respiratory infections at a median of 54.83 hours (IQR, 9.55-104.67 hr) and 1.88 hours (IQR, 0.47-17.40 hr), respectively.

CONCLUSIONS

Phenotypic variation in illness severity and mortality exists when stratified by infection site. There is a significantly higher adjusted and unadjusted odds of the composite outcome of 30-day mortality or shock in respiratory, vascular, and unknown or unspecified infections as compared with other sites.

Sepsis Prediction Model for Determining Sepsis vs SIRS, qSOFA, and SOFA

Importance

The Sepsis Prediction Model (SPM) is a proprietary decision support tool created by Epic Systems; it generates a predicting sepsis score (PSS). The model has not undergone validation against existing sepsis prediction tools, such as Systemic Inflammatory Response Syndrome (SIRS), Sequential Organ Failure Assessment (SOFA), or quick Sepsis-Related Organ Failure Asessement (qSOFA).

Objective

To assess the validity and timeliness of the SPM compared with SIRS, qSOFA, and SOFA.

Design, Setting, and Participants

This retrospective cohort study included all adults admitted to 5 acute care hospitals in a single US health system between June 5, 2019, and December 31, 2020. Data analysis was conducted from March 2021 to February 2023.

Main Outcomes and Measures

A sepsis event was defined as receipt of 4 or more days of antimicrobials, blood cultures collected within ±48 hours of initial antimicrobial, and at least 1 organ dysfunction as defined by the organ dysfunction criteria optimized for the electronic health record (eSOFA). Time zero was defined as 15 minutes prior to qualifying antimicrobial or blood culture order.

Results

Of 60 507 total admissions, 1663 (2.7%) met sepsis criteria, with 1324 electronic health record-confirmed sepsis (699 [52.8%] male patients; 298 [22.5%] Black patients; 46 [3.5%] Hispanic/Latinx patients; 945 [71.4%] White patients), 339 COVID-19 sepsis (183 [54.0%] male patients; 98 [28.9%] Black patients; 36 [10.6%] Hispanic/Latinx patients; and 189 [55.8%] White patients), and 58 844 (97.3%; 26 632 [45.2%] male patients; 12 698 [21.6%] Black patients; 3367 [5.7%] Hispanic/Latinx patients; 40 491 White patients) did not meet sepsis criteria. The median (IQR) age was 63 (51 to 73) years for electronic health record-confirmed sepsis, 69 (60 to 77) years for COVID-19 sepsis, and 60 (42 to 72) years for nonsepsis admissions. Within the vendor recommended threshold PSS range of 5 to 8, PSS of 8 or greater had the highest balanced accuracy for classifying a sepsis admission at 0.79 (95% CI, 0.78 to 0.80). Change in SOFA score of 2 or more had the highest sensitivity, at 0.97 (95% CI, 0.97 to 0.98). At a PSS of 8 or greater, median (IQR) time to score positivity from time zero was 68.00 (6.75 to 605.75) minutes. For SIRS, qSOFA, and SOFA, median (IQR) time to score positivity was 7.00 (-105.00 to 08.00) minutes, 74.00 (-22.25 to 599.25) minutes, and 28.00 (-108.50 to 134.00) minutes, respectively.

Conclusions and Relevance

In this cohort study of hospital admissions, balanced accuracy of the SPM outperformed other models at higher threshold PSS; however, application of the SPM in a clinical setting was limited by poor timeliness as a sepsis screening tool as compared to SIRS and SOFA.

I-SPY COVID adaptive platform trial for COVID-19 acute respiratory failure: rationale, design and operations

INTRODUCTION

The COVID-19 pandemic brought an urgent need to discover novel effective therapeutics for patients hospitalised with severe COVID-19. The Investigation of Serial studies to Predict Your Therapeutic Response with Imaging And moLecular Analysis (ISPY COVID-19 trial) was designed and implemented in early 2020 to evaluate investigational agents rapidly and simultaneously on a phase 2 adaptive platform. This manuscript outlines the design, rationale, implementation and challenges of the ISPY COVID-19 trial during the first phase of trial activity from April 2020 until December 2021.

METHODS AND ANALYSIS

The ISPY COVID-19 Trial is a multicentre open-label phase 2 platform trial in the USA designed to evaluate therapeutics that may have a large effect on improving outcomes from severe COVID-19. The ISPY COVID-19 Trial network includes academic and community hospitals with significant geographical diversity across the country. Enrolled patients are randomised to receive one of up to four investigational agents or a control and are evaluated for a family of two primary outcomes-time to recovery and mortality. The statistical design uses a Bayesian model with 'stopping' and 'graduation' criteria designed to efficiently discard ineffective therapies and graduate promising agents for definitive efficacy trials. Each investigational agent arm enrols to a maximum of 125 patients per arm and is compared with concurrent controls. As of December 2021, 11 investigational agent arms had been activated, and 8 arms were complete. Enrolment and adaptation of the trial design are ongoing.

ETHICS AND DISSEMINATION

ISPY COVID-19 operates under a central institutional review board via Wake Forest School of Medicine IRB00066805. Data generated from this trial will be reported in peer-reviewed medical journals.

TRIAL REGISTRATION NUMBER

NCT04488081.

Intrapleural nano-immunotherapy promotes innate and adaptive immune responses to enhance anti-PD-L1 therapy for malignant pleural effusion

Malignant pleural effusion (MPE) is indicative of terminal malignancy with a uniformly fatal prognosis. Often, two distinct compartments of tumour microenvironment, the effusion and disseminated pleural tumours, co-exist in the pleural cavity, presenting a major challenge for therapeutic interventions and drug delivery. Clinical evidence suggests that MPE comprises abundant tumour-associated myeloid cells with the tumour-promoting phenotype, impairing antitumour immunity. Here we developed a liposomal nanoparticle loaded with cyclic dinucleotide (LNP-CDN) for targeted activation of stimulators of interferon genes signalling in macrophages and dendritic cells and showed that, on intrapleural administration, they induce drastic changes in the transcriptional landscape in MPE, mitigating the immune cold MPE in both effusion and pleural tumours. Moreover, combination immunotherapy with blockade of programmed death ligand 1 potently reduced MPE volume and inhibited tumour growth not only in the pleural cavity but also in the lung parenchyma, conferring significantly prolonged survival of MPE-bearing mice. Furthermore, the LNP-CDN-induced immunological effects were also observed with clinical MPE samples, suggesting the potential of intrapleural LNP-CDN for clinical MPE immunotherapy.

Code status orders and goals of care in the medical ICU

BACKGROUND

Decisions about CPR in the medical ICU (MICU) are important. However, discussions about CPR (code status discussions) can be challenging and may be incomplete if they do not address goals of care.

METHODS

We interviewed 100 patients, or their surrogates, and their physicians in an MICU. We queried the patients/surrogates on their knowledge of CPR, code status preferences, and goals of care; we queried MICU physicians about goals of care and treatment plans. Medical records were reviewed for clinical information and code status orders.

RESULTS

Fifty patients/surrogates recalled discussing CPR preferences with a physician, and 51 recalled discussing goals of care. Eighty-three patients/surrogates preferred full code status, but only four could identify the three main components of in-hospital CPR (defibrillation, chest compressions, intubation). There were 16 discrepancies between code status preferences expressed during the interview and code status orders in the medical record. Respondents' average prediction of survival following in-hospital cardiac arrest with CPR was 71.8%, and the higher the prediction of survival, the greater the frequency of preference for full code status (P = .012). Of six possible goals of care, approximately five were affirmed by each patient/surrogate and physician, but 67.7% of patients/surrogates differed with their physicians about the most important goal of care.

CONCLUSIONS

Patients in the MICU and their surrogates have inadequate knowledge about in-hospital CPR and its likelihood of success, patients' code status preferences may not always be reflected in code status orders, and assessments may differ between patients/surrogates and physicians about what goal of care is most important.

Presumed antepartum amniotic fluid embolism

BACKGROUND

Amniotic fluid embolism is seldom recognized in nonperipartum patients. The pathophysiology is uncertain and diagnosis imprecise, making management after stabilization difficult.

CASE

A 37-year-old woman at 28 weeks' gestation presented with signs and symptoms consistent with amniotic fluid embolism including disseminated intravascular coagulopathy. A ventilation-perfusion scan demonstrated unmatched perfusion defects, but other radiographic studies were negative; the patient was treated with heparin. Four days after presentation she had spontaneous rupture of membranes followed by hypoxemia, necessitating cesarean delivery. A pulmonary arteriogram after the operation showed multiple filling defects; the patient was discharged on warfarin.

CONCLUSION

Amniotic fluid embolism is a difficult diagnosis to make, at best. Anticoagulation may be a therapeutic option.

Respiratory syncytial virus inhibits apoptosis and induces NF-kappa B activity through a phosphatidylinositol 3-kinase-dependent pathway

Respiratory syncytial virus (RSV) infects airway epithelial cells, resulting in cell death and severe inflammation through the induction of NF-kappaB activity and inflammatory cytokine synthesis. Both NF-kappaB activity and apoptosis regulation have been linked to phosphatidylinositol 3-kinase (PI 3-K) and its downstream effector enzymes, AKT and GSK-3. This study evaluates the role of PI 3-K and its downstream mediators in apoptosis and inflammatory gene induction during RSV infection of airway epithelial cells. Whereas RSV infection alone did not produce significant cytotoxicity until 24-48 h following infection, simultaneous RSV infection and exposure to LY294002, a blocker of PI 3-K activity, resulted in cytotoxicity within 12 h. Furthermore, we found that RSV infection during PI 3-K blockade resulted in apoptosis by examining DNA fragmentation, DNA labeling by terminal dUTP nick-end labeling assay, and poly(ADP-ribose) polymerase cleavage by Western blotting. RSV infection produced an increase in the phosphorylation state of AKT, GSK-3, and the p85 regulatory subunit of PI 3-K. The activation of PI 3-K by RSV and its inhibition by LY294002 was confirmed in direct PI 3-K activity assays. Further evidence for the central role of a pathway involving PI 3-K and AKT in preserving cell viability during RSV infection was established by the observation that constitutively active AKT transfected into A549 cells prevented the cytotoxicity and apoptosis of combined RSV and LY294002 treatment. Finally, both PI 3-K inhibition by LY294002 and AKT inhibition by transfection of a dominant negative enzyme blocked RSV-induced NF-kappaB transcriptional activity. These data demonstrate that anti-apoptotic signaling and NF-kappaB activation by RSV are mediated through activation of PI 3-K-dependent pathways. Blockade of PI 3-K activation resulted in rapid, premature apoptosis and inhibition of RSV-stimulated NF-kappaB-dependent gene transcription.

Simultaneous inhibition of Rac1 and IKK pathways sensitizes lung cancer cells to TNFalpha-mediated apoptosis

Lung cancer is the most frequently occurring cancer in the world and causes more deaths in the United States than does colon, breast, and prostate cancer combined. Despite advances in treatment modalities including radiation, surgery, and chemotherapy, the overall survival in lung cancer remains low. The cytokine tumor necrosis factor alpha (TNFalpha) has been shown to regulate both apoptotic and antiapoptotic pathways. Activation of the transcription factor NF-kappaB appears to be the critical determinant of the antiapoptotic response to TNFalpha exposure in epithelial cells. A549 human lung carcinoma cells were infected with adenoviral constructs carrying dominant negative mutants of Rac1 and IKK or constitutively active mutant of Rac1, upstream effectors in TNF-mediated NF-kappaB activation. Cell death, apoptosis, and NF-kappaB activation were subsequently measured in response to TNFalpha exposure. Although TNFalpha alone had no cytotoxic effect, the expression of the dominant negative mutant of IKKbeta (Ad.IKKbetaKA) resulted in apoptotic cell death following TNFalpha exposure. Similarly, dominant negative mutant to Rac1 (Ad.N17Rac1) further sensitized A549 cells to IKKbetaKA-mediated TNFalpha-induced cell death. Conversely, a dominant active form of Rac1 (Ad.V12Rac1) ameliorated the cell death response to concurrent IKKbeta dominant negative mutant infection and TNFalpha exposure. These results suggest that concurrent inhibition of Rac1 and IKK pathways sensitizes lung cancer cells to TNFalpha-induced apoptosis.

The challenge of assessing children's residential exposure to pesticides

In implementing the Food Quality Protection Act (FQPA) the U.S. Environmental Protection Agency (USEPA) has adopted a policy that the exposure factors and models used to assess and predict exposure to pesticides should generally be conservative. Some elements of exposure assessments for FQPA are screening level--they are both uncertain and conservative. If more realistic assessments are to be conducted, then research is required to reduce uncertainty associated with the factors and models used in the exposure assessments. To develop the strategy for conducting this research, critical exposure pathways and factors were identified, and the quality and quantity of data associated with default assumptions for exposure factors were evaluated. Then, based on our current understanding of the pathways that are potentially most important and most uncertain, significant research requirements were identified and prioritized to improve the data available and assumptions used to assess children's aggregate exposure to pesticides. Based on the results of these efforts, four priority research areas were identified: (1) pesticide use patterns in microenvironments where children spend time, (2) temporal and spatial distribution of pesticides following application in a residential setting, (3) dermal and nondietary ingestion exposure assessment methods and exposure factors, (4) dietary exposure assessment methods and exposure factors for infants and young children. The National Exposure Research Laboratory (NERL) research strategy in support of FQPA is designed to address these priority research needs.

Measurement of multi-pollutant and multi-pathway exposures in a probability-based sample of children: practical strategies for effective field studies

The purpose of this manuscript is to describe the practical strategies developed for the implementation of the Minnesota Children's Pesticide Exposure Study (MNCPES), which is one of the first probability-based samples of multi-pathway and multi-pesticide exposures in children. The primary objective of MNCPES was to characterize children's exposure to selected pesticides through a combination of questionnaires, personal exposure measurements (i.e., air, duplicate diet, hand rinse), and complementary monitoring of biological samples (i.e., pesticide metabolites in urine), environmental samples (i.e., residential indoor/outdoor air, drinking water, dust on residential surfaces, soil), and children's activity patterns. A cross-sectional design employing a stratified random sample was used to identify homes with age-eligible children and screen residences to facilitate oversampling of households with higher potential exposures. Numerous techniques were employed in the study, including in-person contact by locally based interviewers, brief and highly focused home visits, graduated subject incentives, and training of parents and children to assist in sample collection. It is not feasible to quantify increases in rates of subject recruitment, retention, or compliance that resulted from the techniques employed in this study. Nevertheless, results indicate that the total package of implemented procedures was instrumental in obtaining a high percentage of valid samples for targeted households and environmental media.

Design strategy for assessing multi-pathway exposure for children: the Minnesota Children's Pesticide Exposure Study (MNCPES)

Although children are exposed to a variety of environmental hazards, including pesticides, there is a scarcity of information available to estimate exposures realistically. This article reports on one of the first attempts to measure multi-pathway pesticide exposures in a population-based sample of urban and non-urban children. A design strategy was developed to assess multi-pathway pesticide exposures in children using personal exposure measurements in combination with complimentary measurements of biological markers of exposure, concentrations in relevant environmental media, and time spent in important microenvironments and participating in exposure-related activities. Sample collection and analysis emphasized measurement of three insecticides (i.e., chlorpyrifos, diazinon, and malathion) and one herbicide (i.e., atrazine). These compounds were selected because of their frequent use, presence in multiple environmental media, expected population exposures, and related hazard/toxicity. The study was conducted during the summer of 1997 in Minnesota and involved a stratified sample of households with children ages 3-12 years. Participants resided in either (a) the cities of Minneapolis and St. Paul (urban households), or (b) Rice and Goodhue Counties just south of the metropolitan area (non-urban households). Results from a residential inventory documenting storage and use of products containing the target pesticides were used to preferentially select households where children were likely to have higher exposures. The study successfully obtained pesticide exposure data for 102 children, including measurements of personal exposures (air, hand rinse, duplicate diet), environmental concentrations (residential indoor/outdoor air, drinking water, residential surfaces, soil), activity patterns (obtained by questionnaire, diary, videotaping), and internal dose (metabolites in urine).

Evaluation of internet-based clinical decision support systems

BACKGROUND

Scientifically based clinical guidelines have become increasingly used to educate physicians and improve quality of care. While individual guidelines are potentially useful, repeated studies have shown that guidelines are ineffective in changing physician behavior. The Internet has evolved as a potentially useful tool for guideline education, dissemination, and implementation because of its open standards and its ability to provide concise, relevant clinical information at the location and time of need.

OBJECTIVE

Our objective was to develop and test decision support systems (DSS) based on clinical guidelines which could be delivered over the Internet for two disease models: asthma and tuberculosis (TB) preventive therapy.

METHODS

Using open standards of HTML and CGI, we developed an acute asthma severity assessment DSS and a preventative tuberculosis treatment DSS based on content from national guidelines that are recognized as standards of care. Both DSS's are published on the Internet and operate through a decision algorithm developed from the parent guidelines with clinical information provided by the user at the point of clinical care. We tested the effectiveness of each DSS in influencing physician decisions using clinical scenario testing.

RESULTS

We first validated the asthma algorithm by comparing asthma experts' decisions with the decisions reached by nonpulmonary nurses using the computerized DSS. Using the DSS, nurses scored the same as experts (89% vs. 88%; p = NS). Using the same scenario test instrument, we next compared internal medicine residents using the DSS with residents using a printed version of the National Asthma Education Program-2 guidelines. Residents using the computerized DSS scored significantly better than residents using the paper-based guidelines (92% vs. 84%; p <0.002). We similarly compared residents using the computerized TB DSS to residents using a printed reference card; the residents using the computerized DSS scored significantly better (95.8% vs. 56.6% correct; p<0.001).

CONCLUSIONS

Previous work has shown that guidelines disseminated through traditional educational interventions have minimal impact on physician behavior. Although computerized DSS have been effective in altering physician behavior, many of these systems are not widely available. We have developed two clinical DSS's based on national guidelines and published them on the Internet. Both systems improved physician compliance with national guidelines when tested in clinical scenarios. By providing information that is coupled to relevant activity, we expect that these widely available DSS's will serve as effective educational tools to positively impact physician behavior.

Sampling design, response rates, and analysis weights for the National Human Exposure Assessment Survey (NHEXAS) in EPA region 5

For the Phase I field test of the National Human Exposure Assessment Survey (NHEXAS) in U.S. Environmental Protection Agency (EPA) Region 5, this paper presents the survey sampling design, the response rates achieved, and the sample weighting procedure implemented to compensate for unit nonresponse. To enable statistically defensible inferences to the entire region, a sample of about 250 members of the household population in EPA Region 5 was selected using a stratified multistage probability-based survey sampling design. Sample selection proceeded in four nested stages: (1) sample counties; (2) area segments based on Census blocks within sample counties; (3) housing units (HUs) within sample segments; and (4) individual participants within sample households. Each fourth-stage sample member was asked to participate in 6 days of exposure monitoring. A subsample of participants was asked to participate in two rounds of longitudinal follow-up data collection. Approximately 70% of all sample households participated in household screening interviews in which rosters of household members were developed. Over 70% of the sample subjects selected from these households completed the Baseline Questionnaire regarding their demographic characteristics and potential for exposures. And, over 75% of these sample members went on to complete at least the core environmental monitoring, including personal exposures to volatile organic compounds (VOCs) and tap water concentrations of metals. The sample weighting procedures used the data collected in the screening interviews for all household members to fit logistic models for nonresponse in the later phases of the study. Moreover, the statistical analysis weights were poststratified to 1994 State population projections obtained from the Bureau of the Census to ensure consistency with other statistics for the Region.

Population-based dietary intakes and tap water concentrations for selected elements in the EPA region V National Human Exposure Assessment Survey (NHEXAS)

A National Human Exposure Assessment Survey (NHEXAS) field study was performed in U.S. Environmental Protection Agency (EPA) Region V, providing population-based exposure distribution data for selected elements in several personal, environmental, and biological media. Population distributions are reported for the 11 elements that were measured in water and dietary samples. Dietary intakes and home tap water concentrations of lead, arsenic, and cadmium were further examined for intermedia associations, for differences between dietary exposure for adults and children, and to estimate the proportion of the population above health-based reference values (dietary) or regulatory action levels or maximum contaminant levels (water). Water lead and arsenic concentrations were significantly associated with dietary intake. Intake of all elements was higher from solid foods than from liquid foods (including drinking water). Dietary intakes of Pb, As, and Cd were greater than those calculated for intake from home tap water or inhalation on a microg/day basis. Median dietary intakes for the Region V population for Pb, As, and Cd were 0.10, 0.13, and 0.19 microg/kg bw/day, respectively. While Pb, As, and Cd concentrations in the foods consumed by 0 to 6-year-old children were similar to or lower than those for adults, dietary intakes calculated on a body weight basis were 1.5 to 2.5 times higher for young children. Intrapersonal intake differences accounted for most of the variance in short-term (daily) dietary intakes for Pb and As, while interpersonal differences accounted for more of the intake variance for Cd. Only small percentages of the population exceeded health-based intake reference values or concentrations equal to regulatory levels in water for Pb, As, and Cd.

Testing duplicate diet sample collection methods for measuring personal dietary exposures to chemical contaminants

Dietary ingestion may be a significant pathway of human exposure to many potentially toxic chemicals. The U.S. Environmental Protection Agency-National Human Exposure Laboratory has made the development of methods for measuring personal dietary exposures a high priority for its dietary exposure research program. Of particular interest was the testing of methods that could be applied in the general population as one component of multipathway exposure measurement studies. This paper describes a controlled pilot study that was conducted to evaluate procedures for collecting and processing duplicate diet samples. Nine adult and three child participants volunteered to provide dietary information for 28 days, and duplicate portions of all foods consumed daily for seven consecutive days. Sample collection procedures were evaluated for participant collection and segregation of solid and liquid foods, and for identification and separation of high-fat and low-fat foods. Methods for compositing and homogenizing mixed diet samples were tested. Food records and questionnaires were tested to document the collected food and to evaluate procedures for assessing dietary changes and collection bias. Participant time and monetary needs were evaluated along with the approach for training and providing support to study participants. Participants were able to collect 96% of the meals they consumed, even with 33% of the meals consumed away from home. Food consumed in social settings was the most difficult to collect, and participants were unable or unwilling to collect foods in some social settings. Noncollection of meals and food items increased after the third day of collection. Mixed diet samples were successfully homogenized, with 1%-11% mean relative standard deviations for moisture, fat, protein, and ash analysis in replicate sample aliquots. The laboratory-measured caloric content of collected foods was an average of 12% (range: -24% to 36%) lower than estimates of energy intake using a food diary and 16% lower than estimated energy expenditure values.

Identification of 1,3-butadiene, benzene, and other volatile organics from wok oil emissions

As part of a program to determine the underlying factors responsible for genotoxicity and perhaps lung cancer risk in Chinese women, we qualitatively identified the volatile components emitted during the heating of cooking oils to 265 degrees C. 1,3-Butadiene, benzene, and a series of aldehydes, olefins, and saturated hydrocarbons were elucidated in vapors from Chinese rapeseed oil. On a relative basis, the intensity of 1,3-butadiene vapors from this were 15.7-, 6.3-, and 1.4-fold greater than in the vapors from peanut, soybean, and Canola oils, respectively. Thus, the Chinese rapeseed oil yielded a higher emission rate of 1,3-butadiene than the other three oils investigated. The benzene formation rate followed a similar trend, i.e., its intensity in Chinese rapeseed oil was 14-, 6.6-, and 1.7-fold greater than in vapors from peanut, soybean, and Canola oils, respectively.

The identification of polar organic compounds found in consumer products and their toxicological properties

Exposure to volatile organic compounds (VOCs) in the indoor environment has received substantial research attention in the past several years, with the goal of better understanding the impact of such exposures on human health and well-being. Many VOCs can arise from consumer products used within the indoor environment. The VOCs emitted from five representative consumer products were collected onto Tenax-GC and subjected to thermal desorption and analysis by gas chromatography, in combination with low-resolution mass spectrometry (MS), high-resolution MS, and matrix-isolation Fourier transform infrared spectroscopy for structural characterization. An emphasis was placed on the polar organic compounds often used to provide fragrance in these products. The structures of a number of these compounds were confirmed, and an electronic literature search was carried out on them to determine any known toxic properties. The search revealed that many of the VOCs possess toxic properties when studied at acute, relatively high-level exposures. In addition, toxic effects were reported for a few of the chemicals, such as benzaldehyde, alpha-terpineol, benzyl acetate, and ethanol, at relatively low dose levels of 9-14 mg/kg. In general, the data were unclear as to the effect of chronic, low-level exposures. The widespread use of such chemicals suggests that the health effects of chronic exposures need to be determined. Validated analytical methods for the quantitative characterization of polar organic compounds at low concentrations will be required to make such work possible.

A breath sampling device for measuring human exposure to volatile organic compounds in microgravity

A compact device for the collection of alveolar air (breath) from humans aboard spacecraft was developed. The system uses silicone one-way valves that operate independent of gravity, and provide minimal backpressure. Small charcoal filters clean ambient air used for inhalation. The device provided good recoveries of organic compounds at the 20 ng/L level, with generally low carryover of these compounds to a blank sample following a sample at exposure to 100 ng/L. When water accumulated in the system, this carryover increased for highly water soluble compounds. The new device was used in parallel with a larger, previously developed alveolar air sampler that requires gravity for proper operation; comparable results were obtained with the two units. The device measures 47 x 34 x 11.4 cm and weighs approximately 3.2 kg. Sufficient space is available within the case to accommodate a number of sample collection options.

Particle Total Exposure Assessment Methodology (PTEAM) study: distributions of aerosol and elemental concentrations in personal, indoor, and outdoor air samples in a southern California community

Particle concentrations were measured for a probability-based sample of 178 nonsmoking individuals aged 10 or older residing in Riverside, California, in the fall of 1990. Two 12-hr personal-exposure PM10 samples were obtained for each participant, along with fixed-location PM10 and PM2.5 indoor and outdoor air samples at their residences. The particle samples were also analyzed via X-ray fluorescence (XRF) to determine elemental concentrations for selected elements, including some toxic metals, crustal elements, and combustion- and industrial-source related elements. About 25% of the target population was estimated to have 24-hr personal exposures to PM10 that exceeded the national ambient air concentration standard of 150 micrograms/m3. The daytime personal exposure levels (median of 130 micrograms/m3) tended to exceed both indoor and outdoor levels by about 50%; nighttime personal exposure levels were lower and were only slightly higher than nighttime indoor levels. Several possible reasons for the elevated daytime personal PM10 levels (relative to indoor levels) are considered. Certain activities such as house cleaning and smoking were found to be associated with elevated personal exposure levels.

Particle Total Exposure Assessment Methodology (PTEAM) 1990 study: method performance and data quality for personal, indoor, and outdoor monitoring

The Particle Total Exposure Assessment Methodology (PTEAM) study provided the opportunity to test methodologies for measuring personal and microenvironmental PM10 and PM2.5 concentrations in a full-scale probability-based sample of 178 persons and homes in Riverside, California during the fall of 1990. The purpose of the study was to estimate frequency distributions of exposure to PM10, PM2.5, and selected elements in an urban population. Quality control samples and analyses were used to evaluate method performance. These included collocated sample collection, field and lab blank filters, sampler and balance field audits, and intra- and interlaboratory replicate elemental analyses. A portion of the study was also designed to include side-by-side operation of the personal and microenvironmental samplers with reference method (high-volume and dichotomous) samplers to provide an evaluation of method comparability. Over 95% of the approximately 2,900 scheduled samples were collected and analyzed, with very few losses due to equipment failure. The method limit of detection for the personal and microenvironmental monitor PM10 sampling was 8 micrograms/m3. Mean relative standard deviations (RSDs) of 2% to 8% were obtained for collocated personal and microenvironmental samples. Sampler flow rates were within the +/- 10% accuracy criterion during two field audits. Balances operated in a specially designed mobile laboratory were within specified tolerances for precision (+/- 4 micrograms) and accuracy (+/- 50 micrograms). Elemental analysis accuracy was measured with standard reference materials with biases ranging from 2% to 7%. Measurement precision for most elements ranged from 2.5% to 25% mean RSD. Personal and microenvironmental samplers gave median PM10 concentrations that were approximately 9% higher than the dichotomous sampler and 16% higher than the high-volume sampler across 96 monitoring periods at a fixed outdoor location.

Temporal variability of benzene exposures for residents in several New Jersey homes with attached garages or tobacco smoke

The U.S. Environmental Protection Agency's (EPA) previous TEAM studies of personal exposure to VOCs for 700 residents in several U.S. cities found that indoor air concentrations were often higher than outdoor levels. Several potential sources of benzene exposure were identified, including environmental tobacco smoke and materials or activities associated with attached garages. Indoor, personal, and outdoor monitoring was conducted at eleven New Jersey homes over multiple 12-hr monitoring periods. One study objective was to assess the impact of attached garages on human exposure to benzene and the variability of benzene exposure across time. Benzene was also measured in several homes inhabited by smokers and in homes without known combustion sources for comparative purposes. At homes with a garage or environmental tobacco smoke, mean indoor and personal benzene concentrations were two to five times higher than outdoor levels at all but one home. Mean personal exposures ranged from 8 to 31 micrograms/m3. Indoor/outdoor ratios were calculated and ranged from 0.8 to 11. Benzene levels in the four garages ranged from 3 to 196 micrograms/m3 and usually were higher than either indoor living areas or personal levels. Multi-zone air exchange rates were measured, and benzene source strengths in each zone were estimated. Garage source strength estimates for benzene ranged from 310 to 52,000 micrograms/h. The mass transfer of benzene from sources in the garage to home living areas was also large in three of the homes, ranging from 730 to 26,000 micrograms/h. Materials or activities in the garage were a source of benzene exposure for the residents in these three homes. Large temporal variations (factors of 2 to 30) were observed in indoor and personal benzene concentrations, indoor/outdoor ratios, and source strengths over the six or ten monitoring periods at each home. Changes in outdoor air benzene levels were an underlying factor in changing exposure levels, with indoor sources further elevating indoor air levels and personal exposures.

Elimination of volatile organic compounds in breath after exposure to occupational and environmental microenvironments

Breath measurements offer the potential for a direct and noninvasive evaluation of human exposure to volatile organic compounds (VOCs) in the environments in which people live and work. This research study was conducted to further evaluate and develop the potential of this exposure assessment methodology. Several people were exposed to the atmosphere in six microenvironments for several hours. Air concentrations of VOCs were measured during these exposures and breath samples were collected and analyzed at multiple time points after the exposure to evaluate elimination kinetics for 21 VOCs. A new alveolar breath collection technique was applied. Elimination half-lives were estimated using a mono- and bi-exponential model. The alveolar breath collection and analysis methodology proved to be very useful for collecting many samples in short time intervals and this capability was very important for more accurately describing the initial phase of the decay curves. Breath decay curves were generated from samples collected over a four hour period after exposure for 21 of 24 target VOCs. A biexponential function generally provided a better fit for the decay data than did the monoexponential function, supporting a multi-compartment uptake and elimination model for the human body.

Effect of dry-cleaned clothes on tetrachloroethylene levels in indoor air, personal air, and breath for residents of several New Jersey homes

Several volatile organic compounds, including tetrachloroethylene, have been found to be nearly ubiquitous in residential indoor environments during previous TEAM studies. Eleven homes in New Jersey were monitored over three or five days to examine the effect of bringing freshly dry-cleaned clothes into the home on indoor air levels and personal exposures to tetrachloroethylene. Indoor air, personal air, and breath concentrations were measured over multiple 12-hrs periods before and after dry-cleaned clothes were introduced into nine of the homes. No dry-cleaned clothes were introduced into the two remaining homes. Outdoor air tetrachloroethylene concentrations were measured at six of the eleven homes. Indoor/outdoor concentration ratios and source strengths were calculated at the six homes with outdoor measurements. Elevated indoor air levels and human exposures to tetrachloroethylene were measured at seven of the nine homes with dry-cleaned clothes. Indoor air concentrations reached 300 micrograms/m3 in one home and elevated indoor levels persisted for at least 48 hrs in all seven homes. Indoor/outdoor tetrachloroethylene concentration ratios exceeded 100 for the four homes with both dry-cleaned clothes and outdoor measurements. Maximum source strengths ranged from 16 to 69 mg/hr in these homes and did not directly correspond to the number of dry-cleaned garments brought into the home. Breath levels of tetrachloroethylene increased two to six-fold for participants living in seven homes with increased indoor air levels. Indoor air, personal air, and breath tetrachloroethylene concentrations were significantly related (0.05 level) to the number of garments introduced divided by the home volume.

A canister-based method for collection and GC/MS analysis of volatile organic compounds in human breath

A method previously used for collection and analysis of volatile organic compounds (VOCs) in human whole breath was modified to encompass compounds with higher vapor pressures. A VOC spirometer was designed for field studies of environmentally exposed populations with breath concentrations in the microgram/m3 (ppb) range. The VOC spirometer was configured for sample collection and GC/MS analysis of breath samples using stainless steel canisters. Recoveries of 17 analytes in synthetic breath through the spirometer at 4 and 21 degrees C were generally above 80% except for n-dodecane which demonstrated poor recoveries at the lower temperature. The maximum sample volume available for analysis during recovery studies with natural breath was 100 mL because of copious quantities of CO2 present. Decay curves showing the breath elimination of 1,1,1-trichloroethane and benzene from a man after exposure to consumer products demonstrates the utility of the method.

A device for sampling of human alveolar breath for the measurement of expired volatile organic compounds

This report describes the development of a portable spirometer capable of collecting primarily alveolar breath into 1.8-L canisters for subsequent gas chromatographic/mass spectrometric (GC/MS) analysis. Based on CO2 measurements, greater than 97% of the breath collected is alveolar in origin. Sample collection takes place in approximately two minutes. Clean air for inhalation is provided by two organic vapor respirator cartridges. Studies of the breakthrough volume of test compounds at both the 5- and 50-micrograms/m3 levels indicate that each cartridge filter can be used to sample over 300 L of air and that this volume is not altered by intermittent use and storage of the filter for up to five days. In experiments designed to mimic human breathing, recoveries of test compounds through the device at the 5-mu/m3 level ranged from 87 to 112%. Essentially no volatile organic compound (VOC) memory (i.e., adsorption carryover by the device) was measured at the 50-micrograms/m3 level. The data suggest that the device can be used successfully for organic compounds with volatilities greater than that of p-dichlorobenzene.

Thiamine deficiency in sheep exported live by sea

Three shipments of sheep being exported live by sea were examined to determine their thiamine status. Measurements were made of thiamine concentration in liver and ruminal contents, transketolase activity in erythrocytes and thiaminase activity in ruminal liquor. Sheep that died or were clinically ill and euthanased had significantly lower hepatic and ruminal thiamine concentrations than clinically healthy control sheep. A high proportion had thiamine concentrations comparable to those found in sheep that die with polioencephalomalacia. Thiamine concentrations decreased with increasing time that sheep were in pre-embarkation feedlots and on board ship. Destruction of thiamine in the rumen by thiaminase was not a significant factor. Erythrocyte transketolase activities indicated that many of the sheep that arrived in the Middle East without signs of clinical disease were also in a state of thiamine insufficiency.

Haemoglobinuria and hypophosphataemia in postparturient dairy cows without dietary deficiency of phosphorus

Postparturient haemoglobinuria occurred in 11 Holstein-Friesian cows in 8 dairy herds in East Gippsland, Victoria. The affected cows had a wide range of ages, body condition and production level. Seven of 9 cows sampled were hypophosphataemic, 4 of 8 cows examined had Heinz bodies present in erythrocytes and strong ketonuria was present in 6 of 10 urine samples tested. Herdmates having similar calving dates had mostly normal serum phosphorus levels and none had Heinz bodies. There was no evidence for dietary phosphorus (P) deficiency, hypocuprosis or excessive P drain from high production being predisposing factors. There were no cruciferous plants in the diet. Haemolysis persisted in 4 cows despite treatment to raise serum P levels. An hyposthesis is proposed for the sporadic nature and clinical manifestations of the disease. This is based on mechanisms of hypophosphataemia occurring in man and mechanisms of Heinz body formation and haemolysis in other circumstances. We suggest that hypophosphataemia occurs following recovery from preparturient keto-acidosis caused by undernutrition in late pregnancy and then becoming nutritionally replete in the early postparturient period. Circulating oxidants may cause erythrocyte damage which may be predisposed to by hypophosphataemia.

Natural establishment of thiaminase activity in the alimentary tract of newborn lambs and effects on thiamine status and growth rates

Thiaminase activity was detected in the faeces of lambs at 2 to 5 days of age. Levels of activity increased for 10 days and then declined over the next 3 to 4 weeks. Decreased erythrocyte transketolase activity indicated thiamine insufficiency in lambs with high thiaminase activity. Mean growth rates were 17% less in lambs with high thiaminase activity than in lambs with zero or low thiaminase activity. Bacillus thiaminolyticus was the only organism isolated which produced thiaminase. Treatment of newborn lambs with intramuscular injections of sulphadoxine did not prevent them from excreting thiaminase in their faeces. It is proposed that oral thiamine supplementation of lambs at 2 to 3 weeks of age may be the most appropriate prevention and treatment for subclinical thiamine deficiency of the cause described.

Oral treatment of polioencephalomalacia and subclinical thiamine deficiency with thiamine propyl disulphide and thiamine hydrochloride

Thiaminase type I production by Bacillus thiaminolyticus and activity in vitro were repressed by the primary substate thiamine and by thiamine monophosphate and thiamine propyl disulphide. At thiamine concentrations of 300-3000 mumol/l production of active enzyme by B. thiaminolyticus, and activity of purified enzyme, were totally repressed. Growth of B. thiaminolyticus was inhibited by thiamine propyl disulphide at 3000 mumol/l. Activity of purified thiaminase was lost when incubated with ruminal fluid from healthy thiaminase free sheep. Enzyme activity was also lost when exposed to mildly alkaline conditions but was stimulated and stabilized against heat denaturation if treated with dithiothreitol. Thiaminase activities in the ruminal fluids of cases of ovine polioencephalomalacia were repressed within 2 h of oral administration of thiamine propyl disulphide. Blood pyruvate levels and transketolase activities were restored to normal following treatment. Treated animals recovered clinically and were returned to pasture.

The effect of thiaminase-induced subclinical thiamine deficiency on growth of weaner sheep

Three experiments were performed to examine for causes of poor growth of young Merino sheep. Weekly testing of animals 42 weeks of age for 10 weeks revealed that 90% of clinically poor animals were excreting high levels of thiaminase in their faeces; low levels of activity were present in 20% of clinically normal animals. There were significant differences in the mean erythrocyte transketolase activity of the thiaminase excreting poor animals and the thiaminase free normal animals. Other known causes of poor growth could not be demonstrated. Weekly monitoring of thiaminase activity in the faeces from 80 lambs 6 weeks of age showed 23% to be excreting significant levels of enzyme (greater than 3mUg-1 DM) throughout a 10 week test period. Mean growth rates of these lambs were significantly below those of lambs not excreting thiaminase or excreting low levels intermittently. Supplementation of thiaminase excreting lambs with intra-muscular injections of thiamine HCl was associated with a statistically significant improved growth rate (P less than 0.01) compared to unsupplemented sheep excreting thiaminase. Mean growth rates of lambs not excreting thiaminase on a continuous basis (sampled weekly) were the same with or without thiamine HCl supplementation. High thiaminase levels were found in the ruminal fluids of trial animals excreting the enzyme in their faeces, confirming this previously established association. Bacillus thiaminolyticus was isolated from faeces and ruminal fluids from clinically poor animals and is the most likely source of the thiaminase. Subclinical thiamine deficiency was indicated by low erythrocyte transketolase activities and elevated TPP effects and is proposed as the cause of the poor growth by the young sheep.

Levels of trace elements in the liver and diet of free-living koalas, Phascolarctos cinereus (Goldfuss)

The mean liver concentrations of copper, manganese, zinc and cobalt were 0.25, 0.20, 2.97 mmol/kg and 2.81 mumol/kg respectively in free-living koalas in Victoria, Australia. The mean plasma copper concentration was 9.2 mmol/liter which was somewhat below the level in other hindgut fermenters. The mean concentrations of copper, manganese and zinc in their diet (Eucalyptus spp.) were 0.08, 4.46 and 0.27 mmol/kg respectively. Analysis of the data established a significant correlation between the age of the koalas and the inverse of the concentration of the copper (r = -0.67, P less than 0.001) in the liver. There were no such correlations apparent for manganese, zinc or cobalt. The concentrations of trace metals in the Eucalyptus diet for the koala were comparable to those recommended in the diets for other hindgut fermenters such as horse, rabbits and rats. However there was evidence for suboptimal plasma copper levels (mean 9.2 mmol/liter) in some koalas, and reduced liver copper levels in older koalas. Liver histology revealed the presence of brown intracytoplasmic granules in hepatocytes. The size and number of these granules per cell was noted to increase with increasing age of the koala but the chemical nature and the role of the granules was not determined by the histochemical techniques used.

White liver disease of sheep

Outbreaks of ovine white liver disease (WLD) on 7 farms in eastern Victoria were investigated. Most occurred in late spring and mainly affected lambs 3 to 6 months old, with a morbidity of 20 to 100% and mortality of 8 to 15%. Clinically affected lambs showed illthrift, emaciation and bilateral, serous, ocular discharge. Clinical pathology showed mild anaemia, elevated serum liver enzymes (GGT, OCT, AST) and low levels of serum vitamin B12. Grossly, the livers were pale, fatty and friable; microscopically there was parenchymal fatty change, bile duct proliferation and ceroid pigmentation. Liver cobalt values were consistently low (mean 0.4 +/- 0.4 mumol/kg D.W.). Levels of cobalt in pasture from 2 properties were very low (0.34 mumol/kg D.W.) The diagnosis of white liver disease was made on the basis of clinical features, specific liver pathology and low cobalt status. Treatment trials established that cobalt injections or oral bullet administration resulted in clinical improvement, significant weight gains, and improved serum vitamin B12 levels. WLD did not recur in previously affected sheep using these treatments. However, when blocks containing cobalt were available continuously, WLD recurred 2 years after the initial outbreak.

Beyond expectancy theory: an integrative motivational model from health care

Expectancy theory has been criticized for its omission of normative, habitual, and other motivational elements. This paper describes the sources and features of an integrative motivational model from the field of preventive health care that combines expectancy/valence factors with habitual, normative, and conative motivational elements. The model is viewed as having implications for work motivation as well.

The use of immunochemically purified anti-brucella antibody in a direct fluorescent antibody test for Brucella abortus

Antibodies specific for Brucella abortus were purified from the serum of hyperimmunized sheep using immunochemical procedures. They were conjugated to fluorescein isothiocyanate and used in a fluorescent antibody (FA) test for B. abortus. The conjugate did not stain any heterologous bacterial or fungal species tested and background fluorescence associated with its use on smears and sections of abortion materials was particularly low. Of 239 cases of abortion examined fluorescent microscopy demonstrated B. abortus in all 12 cases in which the organism was isolated. A few areas of fluorescence typical of B. abortus were also seen in 3 cases from which the organism was not cultured. B. abortus was demonstrated in lymph nodes from 6 of 36 Brucella reactor cows by culture and 7 by the FA test. However, only very low numbers of B. abortus were isolated or seen and sampling errors would have been significant. Use of the FA test allows diagnosis of Brucellosis to be made in 2 hours, compared to 6 days by the usual cultural procedures.

Hypogammaglobulinaemia in foals: prevalence on Victorian studs and simple methods for detection and correction in the field

The prevalence of hypogammaglobulinaemia in 82 young foals was determined. Twelve foals were considered clinically abnormal at birth and ten died within two weeks. All of these foals were hypogammaglobulinaemic. Seven (10%) of the other 70 apparently normal foals were hypogammaglobulinaemic despite having suckled normally. Three of these foals developed significant disease and one died at one month of age. Rapid detection of foals with low serum immunoglobulin levels was achieved by adapting the zinc sulphate turbidity test to partially evacuated blood collection tubes. This permitted test to be conducted on the stud or in the veterinarian's own laboratory. Plasma concentrated twofold by a freeze thaw technique was administered intravenously to supplement the immunoglobulin levels of two colostrum deprived foals. The simplicity of the concentration procedure eliminated the need for laboratory preparation of equine immunoglobulin.

A freeze-thaw method for concentrating plasma and serum for treatment of hypogammaglobulinaemia

Components of plasma or serum, including immunoglobulins, were concentrated two-fold by freezing then collecting 40-50% of the initial volume during thawing. This concentrated plasma (or serum) was administered intravenously to treat hypogammaglobulinaemic foals and calves. An adaptation of this method suitable for field use is described.

Manganese levels and the morphology of the epiphyseal plate in broilers with slipped tendons

Manganese deficiency in chickens results in perosis and a higher incidence of slipped tendon. Perosis is associated with a disorganization of the epiphyseal growth plates and changes in the chemical composition of the cartilage matrix. Male broilers with slipped tendons were selected from a commercial broiler farm over a 9 week growing period. Their growth rates, epiphyseal cartilage histology and tissue manganese concentrations were examined and compared with (a) normal broilers from the same farm, and (b) similar broilers raised on control and manganese deficient diets. Field broilers with slipped tendons showed no evidence of abnormality in the histological appearance of the proximal tibial growth plate at any of the ages examined. The manganese content of liver and epiphyseal cartilage from field broilers showing slipped tendon was comparable with that present in tissue from normal broilers wither from the field or raised on a chemically defined diey supplemented with managese. The slightly retared growth rate seen in the field broilers was attributed to feeding problems associated with the lameness condition. These results provide conclusive evidence that slipped tendon in field broilers is not dur to a manganese deficiency in the tissues, nor does it appear to be associated with abnormal proliferation of the chondrocytes in the epiphyseal plate.

Official statistics and blindness in Hong Kong

WHO designated 1976 as the year for the prevention of blindness and attention is drawn to the prevalence rate and causes of blindness in Hong Kong. The former as released by WHO is as high as 1392 per 100,000 and the latter tends to suggest Vitamin A deficiency is still an important cause here. This article reviews all the official statistics on blindness published in Hong Kong over the past twenty years and seeks to suggest an appropriate prevalence rate for Hong Kong and demonstrate the changing pattern of causes of blindness in Hong Kong. It concludes that Hong Kong should adopt a statistical definition and classification of blindness accepted internationally and suggests that in the presentation of statistics, the misleading factor of present inclusion of past events should be avoided.

Interpersonal conflict-handling behavior as reflections of Jungian personality dimensions

This study has sought to investigate the Jungian psychological correlates of an individual's choice of different interpersonal conflict-handling modes: competing, collaborating, compromising, avoiding, and accommodating. These five modes were defined according to the two basic behavioral dimensions of assertiveness and cooperativeness and were also related to integrative and distributive dimensions. The results suggest that the Jungian functions related to judging (thinking vs feeling) and the type of enactment (introverted vs extraverted) are significantly related to an individual's conflict-handling behavior. The study concludes with a schematic illustration of these Jungian functions plotted upon the basic behavioral dimensions which define and characterize the five conflict-handling modes.