Eye and airway symptoms in hospital staff exposed to a product containing hydrogen peroxide, peracetic acid, and acetic acid

BACKGROUND

Sporicidal products containing hydrogen peroxide (HP), peracetic acid (PAA), and acetic acid (AA) are used widely in multiple industries, including healthcare. Despite widespread use in healthcare, few studies have assessed associations between exposures to HP, PAA, and AA, and work-related symptoms in these settings.

METHODS

In 2018, we performed a health and exposure assessment at a hospital where a sporicidal product consisting of HP, PAA, and AA, was used as the primary cleaner on hospital surfaces. We collected 56 personal and mobile air samples for HP, PAA, and AA on participants while they performed their regular cleaning duties; collected area samples for HP (n = 28), PAA (n = 28), and AA (n = 70) in multiple hospital locations where cleaning was performed; and administered a postshift survey to assess eye, skin, and upper and lower airway symptoms that occurred cross-shift or in the previous 4 weeks.

RESULTS

Full-shift exposure levels for HP (range: <3-559 ppb), PAA (range: <0.2-8 ppb), and AA (range: <5-915 ppb) were all below US occupational exposure limits. We observed positive associations (p < 0.05) between shift, departmental average, and departmental 95th percentile exposures to HP, PAA, and AA vapors, and work-related acute (cross-shift) and chronic (previous 4 weeks) eye, upper airway, and lower airway symptoms after adjusting for age, gender, smoking status, use of other cleaning products containing sensitizers and irritants, allergic status, and stress.

CONCLUSIONS

Our observations of work-related upper and lower airway symptoms among hospital workers exposed to vapors from a sporicidal product containing HP, PAA, and AA indicate a need for a combination of engineering, administrative, and PPE controls to reduce exposure. Additionally, alternative nonchemical disinfection technologies should be further investigated as a means to simultaneously reduce healthcare workers' exposure to disinfectants while also minimizing costly healthcare-acquired infections.

Decrements in lung function and respiratory abnormalities associated with exposure to diacetyl and 2,3-pentanedione in coffee production workers

Coffee production workers are exposed to complex mixtures of gases, dust, and vapors, including the known respiratory toxins, diacetyl, and 2,3-pentanedione, which occur naturally during coffee roasting and are also present in flavorings used to flavor coffee. This study evaluated the associations of these two α-diketones with lung function measures in coffee production workers. Workers completed questionnaires, and their lung function was assessed by spirometry and impulse oscillometry (IOS). Personal exposures to diacetyl, 2,3-pentanedione, and their sum (Sum_DA+PD) were assigned to participants, and metrics of the highest 95th percentile (P95), cumulative, and average exposure were calculated. Linear and logistic regression models for continuous and binary/polytomous outcomes, respectively, were used to explore exposure-response relationships adjusting for age, body mass index, tenure, height, sex, smoking status, race, or allergic status. Decrements in percent predicted forced expiratory volume in 1 second (ppFEV₁) and forced vital capacity (ppFVC) were associated with the highest-P95 exposures to 2,3-pentanedione and Sum_DA+PD. Among flavoring workers, larger decrements in ppFEV₁ and ppFVC were associated with highest-P95 exposures to diacetyl, 2,3-pentanedione, and Sum_DA+PD. Abnormal FEV₁, FVC, and restrictive spirometric patterns were associated with the highest-P95, cumulative, and average exposures for all α-diketone metrics; some of these associations were also present among flavoring and non-flavoring workers. The combined category of small and peripheral airways plus small and large airways abnormalities on IOS had elevated odds for highest-P95 exposure to α-diketones. These results may be affected by the small sample size, few cases of abnormal spirometry, and the healthy worker effect. Associations between lung function abnormalities and exposure to α-diketones suggest it may be prudent to consider exposure controls in both flavoring and non-flavoring settings.

Determinants of Task-Based Exposures to Alpha-Diketones in Coffee Roasting and Packaging Facilities Using a Bayesian Model Averaging Approach

Coffee production workers can be exposed to inhalational hazards including alpha-diketones such as diacetyl and 2,3-pentanedione. Exposure to diacetyl is associated with the development of occupational lung disease, including obliterative bronchiolitis, a rare and irreversible lung disease. We aimed to identify determinants contributing to task-based exposures to diacetyl and 2,3-pentanedione at 17 U.S. coffee production facilities. We collected 606 personal short-term task-based samples including roasting (n = 189), grinding (n = 74), packaging (n = 203), quality control (QC, n = 44), flavoring (n = 15), and miscellaneous production/café tasks (n = 81), and analyzed for diacetyl and 2,3-pentanedione in accordance with the modified OSHA Method 1013/1016. We also collected instantaneous activity-based (n = 296) and source (n = 312) samples using evacuated canisters. Information on sample-level and process-level determinants relating to production scale, sources of alpha-diketones, and engineering controls was collected. Bayesian mixed-effect regression models accounting for censored data were fit for overall data (all tasks) and specific tasks. Notable determinants identified in univariate analyses were used to fit all plausible models in multiple regression analysis which were summarized using a Bayesian model averaging method. Grinding, flavoring, packaging, and production tasks with ground coffee were associated with the highest short-term and instantaneous-activity exposures for both analytes. Highest instantaneous-sources of diacetyl and 2,3-pentanedione included ground coffee, flavored coffee, liquid flavorings, and off-gassing coffee bins or packages. Determinants contributing to higher exposures to both analytes in all task models included sum of all open storage sources and average percent of coffee production as ground coffee. Additionally, flavoring ground coffee and flavoring during survey contributed to notably higher exposures for both analytes in most, but not all task groups. Alternatively, general exhaust ventilation contributed to lower exposures in all but two models. Additionally, among facilities that flavored, local exhaust ventilation during flavoring processes contributed to lower 2,3-pentanedione exposures during grinding and packaging tasks. Coffee production facilities can consider implementing additional exposure controls for processes, sources, and task-based determinants associated with higher exposures to diacetyl and 2,3-pentanedione, such as isolating, enclosing, and directly exhausting grinders, flavoring mixers, and open storage of off-gassing whole bean and ground coffee, to reduce exposures and minimize risks for lung disease among workers.

Influence of E-Liquid Humectants, Nicotine, and Flavorings on Aerosol Particle Size Distribution and Implications for Modeling Respiratory Deposition

Electronic cigarette, or vaping, products are used to heat an e-liquid to form an aerosol (liquid droplets suspended in gas) that the user inhales; a portion of this aerosol deposits in their respiratory tract and the remainder is exhaled, thereby potentially creating opportunity for secondhand exposure to bystanders (e.g., in homes, automobiles, and workplaces). Particle size, a critical factor in respiratory deposition (and therefore potential for secondhand exposure), could be influenced by e-liquid composition. Hence, the purposes of this study were to (1) test the influence of laboratory-prepared e-liquid composition [ratio of propylene glycol (PG) to vegetable glycerin (VG) humectants, nicotine, and flavorings] on particle size distribution and (2) model respiratory dosimetry. All e-liquids were aerosolized using a second-generation reference e-cigarette. We measured particle size distribution based on mass using a low-flow cascade impactor (LFCI) and size distribution based on number using real-time mobility sizers. Mass median aerodynamic diameters (MMADs) of aerosol from e-liquids that contained only humectants were significantly larger compared with e-liquids that contained flavorings or nicotine (p = 0.005). Humectant ratio significantly influenced MMADs; all aerosols from e-liquids prepared with 70:30 PG:VG were significantly larger compared with e-liquids prepared with 30:70 PG:VG (p = 0.017). In contrast to the LFCI approach, the high dilution and sampling flow rate of a fast mobility particle sizer strongly influenced particle size measurements (i.e., all calculated MMAD values were &lt; 75 nm). Dosimetry modeling using LFCI data indicated that a portion of inhaled particles will deposit throughout the respiratory tract, though statistical differences in aerosol MMADs among e-liquid formulations did not translate into large differences in deposition estimates. A portion of inhaled aerosol will be exhaled and could be a source for secondhand exposure. Use of laboratory-prepared e-liquids and a reference e-cigarette to standardize aerosol generation and a LFCI to measure particle size distribution without dilution represents an improved method to characterize physical properties of volatile aerosol particles and permitted determination of MMAD values more representative of e-cigarette aerosol in situ, which in turn, can help to improve dose modeling for users and bystanders.

Respiratory Symptoms in Hospital Cleaning Staff Exposed to a Product Containing Hydrogen Peroxide, Peracetic Acid, and Acetic Acid

Cleaning and disinfecting products consisting of a mixture of hydrogen peroxide (HP), peracetic acid (PAA), and acetic acid (AA) are widely used as sporicidal agents in health care, childcare, agricultural, food service, and food production industries. HP and PAA are strong oxidants and their mixture is a recognized asthmagen. However, few exposure assessment studies to date have measured HP, PAA, and AA in a health care setting. In 2015, we performed a health and exposure assessment at a hospital where a new sporicidal product, consisting of HP, PAA, and AA was introduced 16 months prior. We collected 49 full-shift time-weighted average (TWA) air samples and analyzed samples for HP, AA, and PAA content. Study participants were observed while they performed cleaning duties, and duration and frequency of cleaning product use was recorded. Acute upper airway, eye, and lower airway symptoms were recorded in a post-shift survey (n = 50). A subset of 35 cleaning staff also completed an extended questionnaire that assessed symptoms reported by workers as regularly occurring or as having occurred in the previous 12 months. Air samples for HP (range: 5.5 to 511.4 ppb) and AA (range: 6.7 to 530.3 ppb) were all below established US occupational exposure limits (OEL). To date, no full-shift TWA OEL for PAA has been established in the United States, however an OEL of 0.2 ppm has been suggested by several research groups. Air samples for PAA ranged from 1.1 to 48.0 ppb and were well below the suggested OEL of 0.2 ppm. Hospital cleaning staff using a sporicidal product containing HP, PAA, and AA reported work-shift eye (44%), upper airway (58%), and lower airway (34%) symptoms. Acute nasal and eye irritation were significantly positively associated with increased exposure to the mixture of the two oxidants: HP and PAA, as well as the total mixture (TM)of HP, PAA, and AA. Shortness of breath when hurrying on level ground or walking up a slight hill was significantly associated with increased exposure to the oxidant mixture (P = 0.017), as well as the TM (P = 0.026). Our results suggest that exposure to a product containing HP, PAA, and AA contributed to eye and respiratory symptoms reported by hospital cleaning staff at low levels of measured exposure.

Current asthma and asthma-like symptoms among workers at a Veterans Administration Medical Center

INTRODUCTION

Healthcare workers are at increased risk for respiratory disorders. The purpose of our respiratory health survey was to estimate the prevalence of current asthma and asthma-like symptoms and their association with workplace exposures and tasks among healthcare workers at a Veterans Administration (VA) Medical Center.

MATERIAL AND METHODS

Information on respiratory health and work characteristics, including tasks performed, products used, and exposures, were collected by questionnaire from a convenience sample of workers employed at the VA Medical Center during 2012-2014. Associations of asthma and asthma-like symptoms with cleaning and disinfecting tasks and products as well as exposure to dampness and molds, and construction dust were evaluated using log-binomial regression.

RESULTS

The prevalence of current asthma was 17.6% and almost half of all workers reported asthma-like symptoms. We observed elevated prevalence of current asthma among the VA healthcare workers compared to the U.S. general and working adult populations. Asthma and asthma-like symptoms were significantly associated with mold, dampness, and construction material exposures; cleaning and disinfecting products; and cleaning or disinfecting tasks.

CONCLUSIONS

Workplace exposures and tasks associated with current asthma and asthma-like symptoms were identified but further research is needed to investigate the temporal association between workplace exposures and current asthma and asthma-like symptoms.

Air and Surface Sampling Method for Assessing Exposures to Quaternary Ammonium Compounds Using Liquid Chromatography Tandem Mass Spectrometry

This method was designed for sampling select quaternary ammonium (quat) compounds in air or on surfaces followed by analysis using ultraperformance liquid chromatography tandem mass spectrometry. Target quats were benzethonium chloride, didecyldimethylammonium bromide, benzyldimethyldodecylammonium chloride, benzyldimethyltetradecylammonium chloride, and benzyldimethylhexadecylammonium chloride. For air sampling, polytetrafluoroethylene (PTFE) filters are recommended for 15-min to 24-hour sampling. For surface sampling, Pro-wipe® 880 (PW) media was chosen. Samples were extracted in 60:40 acetonitrile:0.1% formic acid for 1 hour on an orbital shaker. Method detection limits range from 0.3 to 2 ng/ml depending on media and analyte. Matrix effects of media are minimized through the use of multiple reaction monitoring versus selected ion recording. Upper confidence limits on accuracy meet the National Institute for Occupational Safety and Health 25% criterion for PTFE and PW media for all analytes. Using PTFE and PW analyzed with multiple reaction monitoring, the method quantifies levels among the different quats compounds with high precision (<10% relative standard deviation) and low bias (<11%). The method is sensitive enough with very low method detection limits to capture quats on air sampling filters with only a 15-min sample duration with a maximum assessed storage time of 103 days before sample extraction. This method will support future exposure assessment and quantitative epidemiologic studies to explore exposure-response relationships and establish levels of quats exposures associated with adverse health effects.

Annual decline in forced expiratory volume is steeper in aluminum potroom workers than in workers without exposure to potroom fumes

Background

Aluminum potroom exposure is associated with increased mortality of COPD but the association between potroom exposure and annual decline in lung function is unknown. We have measured lung volumes annually using spirometry from 1986 to 1996. The objective was to compare annual decline in forced expiratory volume in 1 s (dFEV1) and forced vital capacity (dFVC).

Methods

The number of aluminum potroom workers was 4,546 (81% males) and the number of workers in the reference group was 651 (76% males). The number of spirometries in the index group and the references were 24,060 and 2,243, respectively.

Results

After adjustment for confounders, the difference in dFEV1 and dFVC between the index and reference groups were 13.5 (P < 0.001) and −8.0 (P = 0.060) ml/year.

Conclusion

Aluminum potroom operators have increased annual decline in FEV1 relative to a comparable group with non‐exposure to potroom fumes and gases. Am. J. Ind. Med. 59:322–329, 2016. © 2016 The Authors. American Journal of Industrial Medicine Published by Wiley Periodicals, Inc.

Construction of a Job Exposure Matrix to Dust, Fluoride, and Polycyclic Aromatic Hydrocarbons in the Norwegian Aluminum Industry using Prediction Models

BACKGROUND

The Norwegian aluminum industry developed and implemented a protocol for prospective monitoring of employees' exposure using personal samplers. We analyzed these data to develop prediction lines to construct a job exposure matrix (JEM) for the period 1986-1995.

METHODS

The protocol for personal monitoring of exposure was implemented in all seven Norwegian aluminum plants in 1986 and continued until 1995. Personal samplers were used to collect total dust, fluorides, and total polycyclic aromatic hydrocarbons (PAH). In addition, exposure could be categorized according to process, i.e. prebake, Søderberg, and 'other'. We constructed four-dimensional JEMs characterized by: Plant, Job descriptor, Process, and Year. Totally 8074, 6734, and 3524 measurements were available for dust, fluorides, and PAH, respectively. The data were analyzed using linear mixed models with two-way interactions. The models were assessed using the Akaike criterion (AIC) and unadjusted R (2). The significance level was set to 10% (two-sided) for retaining variables in the model.

RESULTS

In 1986, the geometric mean (95% confidence interval in parentheses) for total dust, total fluorides, and PAH were 3.18 (0.46-22.2) mg m(-3), 0.58 (0.085-4.00) mg m(-3), and 33.9 (2.3-504) µg m(-3), respectively. During 10 years of follow-up, the exposure to total dust, fluorides, and PAH decreased by 9.2, 11.7, and 14.9% per year, respectively. Each model encompassed from 49 to 72 significant components of the interaction terms. The interaction components were at least as important as the main effects, and 65 to 91% of the significant components of the interaction terms were time-dependent.

CONCLUSION

Our prediction models indicated that exposures were highly time-dependent. We expect that the time-dependent changes in exposure are of major importance for longitudinal studies of health effects in the aluminum industry.

Harmonization of measurement strategies for exposure to manufactured nano-objects; report of a workshop

The present paper summarizes the outcome of the discussions at the First International Scientific Workshop on Harmonization of Strategies to Measure and Analyze Exposure to (Manufactured) Nano-objects in Workplace Air that was organized and hosted by the Netherlands Organization for Applied Scientific Research (TNO) and the Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA) (Zeist, The Netherlands, December 2010). It reflects the discussions by 25 international participants in the area of occupational (nano) exposure assessment from Europe, USA, Japan, and Korea on nano-specific issues related to the three identified topics: (i) measurement strategies; (ii) analyzing, evaluating, and reporting of exposure data; and (iii) core information for (exposure) data storage. Preliminary recommendations were achieved with respect to (i) a multimetric approach to exposure assessment, a minimal set of data to be collected, and basic data analysis and reporting as well as (ii) a minimum set of contextual information to be collected and reported. Other issues that have been identified and are of great interest include (i) the need for guidance on statistical approaches to analyze time-series data and on electron microscopy analysis and its reporting and (ii) the need for and possible structure of a (joint) database to store and merge data. To make progress in the process of harmonization, it was concluded that achieving agreement among researchers on the preliminary recommendations of the workshop is urgent.

Identifying the determinants of viable microorganisms in the air and bulk metalworking fluids

Exposure assessment was conducted for an epidemiologic study of the respiratory effects of exposure to metalworking fluids (MWF). As part of the study, airborne microorganisms were collected with a two-stage microbial impactor, and a sample of the bulk soluble MWF was collected from each machine sump, as well as information about the work environment. These data were then used to develop multivariate statistical models of the determinants bulk MWF and airborne microbial levels. Microbial concentrations in the bulk MWF ranged from 5 x 10(4) to 5 x 10(10) colony-forming units (CFU)/mL, with a geometric mean of 3.4 x 10(7) CFU/mL. The geometric mean airborne microbial level was 182 CFU/m3 (for particles size <8 microm) with a range of 1 to 8,308 CFU/m3. In modeling the determinants of bulk microorganisms, fluid-related factors were the most important characteristics associated with microbial levels, followed by process-related and environmental factors. The final full multivariate model predicted a significant reduction in bulk microbial levels by increasing pH of the fluid and reducing the amount of tramp oil leaking into the fluid. For the airborne microbial models, process-related factors were the major characteristics associated with microbial levels, followed by factors related to worker activities and environmental factors. The final full multivariate model predicted a significant control of airborne microorganisms by increasing worker distance from the machine, reducing the number of machines within 10 feet of the worker, decreasing the bulk microbial levels, and adding machine enclosures. These models can be used to prioritize nonbiocidal interventions to control microbial contamination of the bulk MWF and the air.

Biomarkers of liver regeneration allow early prediction of hepatic recovery after acute necrosis

Acute toxic hepatic necrosis is common and may be fatal. Predicting clinical outcome may be aided by following serum markers that could indicate recovery or may signify massive (substantial) destruction of functional liver mass. Previously, in a published case of chloroform poisoning, we serially assayed serum biomarkers of hepatocellular necrosis (aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase) and markers of hepatocellular regeneration (alpha-fetoprotein, retinol-binding protein, gamma-glutamyl transferase, and des-gamma-carboxyprothrombin). We noted a decline in necrotic markers and a synchronous elevation in regenerative markers, which could be suggestive of a favorable outcome in similar cases. We now report 6 Amanita mushroom poisonings with favorable outcome and 2 fatal acetaminophen poisonings in which the same markers were observed. Our results further support our hypothesis that a sustained decline in serum markers of hepatocyte necrosis with a concurrent elevation in regenerative markers could aid in prediction of favorable outcome in patients with acute liver injury.

Concise parathyroidectomy: the impact of preoperative SPECT 99mTc sestamibi scanning and intraoperative quick parathormone assay

BACKGROUND

Results of initial operation for sporadic primary hyperparathyroidism are generally excellent, yet today there is pressure to improve outcome and resource utilization.

METHODS

We designed a prospective longitudinal cohort study comparing two approaches to concise parathyroidectomy. Strategy A was defined as the palpation method for selective unilateral exploration. Strategy B was defined as the routine use of both preoperative 99mTc sestamibi single photon emission computed tomography (SPECT) imaging and intraoperative quick parathormone assay. With either strategy the study period was 19 months and patients explored unilaterally were candidates for same-day discharge. We compared surgical outcome for 128 consecutive consenting patients each with 6 months or more of follow-up (mean 12 +/- 7.6 months).

RESULTS

Demographic, biochemical and pathologic findings did not differ between groups. SPECT imaging precisely localized hyperfunctioning parathyroid tissue. Compared with Strategy A (n = 61), the 67 patients treated by use of Strategy B experienced a higher rate of unilateral exploration (41.0% versus 62.7%, p < 0.00001) and a shorter length of stay (1.07 versus 1.90 days, p < 0.00001) and tended to have shorter operative times, fewer operative failures, and less morbidity. Total perioperative costs did not differ between groups.

CONCLUSIONS

Routine use of intraoperative quick parathormone measurement and preoperative 99mTc sestamibi SPECT is as safe, effective, and cost-effective as conventional approaches to parathyroidectomy. Use of this strategy is associated with significant reductions in extent of surgery and length of hospital stay.

A field investigation of the acute respiratory effects of metal working fluids. II. Effects of airborne sulfur exposures

An investigation of the acute respiratory effects of workers exposed to metal working fluids (MWF) was conducted in an automobile parts manufacturing facility. After observing an association between cross-shift decline in forced expiratory volume in the first second (FEV1) and aerosol mass concentration, improved characterization of the exposure was sought through investigation of four elements of a priori interest (Cl, Cr, Ni, S). Of these, only sulfur showed an association with cross-shift FEV1 decrement. The relative risk of 5% cross-shift FEV1 decrement was 2.7 (95% confidence interval = 1.0-6.0) comparing those with > 4.4 micrograms/m3 to those with < 2.5 micrograms/m3 sulfur exposure. Because the concentrations of sulfur in this environment were relatively low and other respiratory irritants were present, sulfur is more likely to be an indicator of more irritating conditions than the sole agent responsible for the observed acute respiratory effects.

A field investigation of the acute respiratory effects of metal working fluids. I. Effects of aerosol exposures

A study of cross-shift change in pulmonary function was conducted among workers exposed to metal working fluids (MWF) in an automobile parts manufacturing company. Three hundred eighty-six workers (216 machinists exposed to straight or soluble MWFs, and 170 nonmachinists) were studied for 1 day, performing spirometry at the beginning and end of their shift. Airborne concentrations of inhalable particulate, culturable bacteria, and endotoxin were measured. We observed an approximately threefold increase in the incidence of 5% or greater cross-shift decrement in forced expiratory volume during the first second among those with exposures above about 0.15 mg/m3, compared to those with exposures below about 0.08 mg/m3. There was some evidence that chronic respiratory symptoms were more prevalent among machinists than among nonmachinists, notably for chronic cough. Baseline FEV1 was about 3% lower on average among those with soluble MWF exposure compared to nonmachinists. These findings are consistent with earlier studies showing respiratory effects of MWFs.

A field investigation of the acute respiratory effects of metal working fluids. II. Effects of airborne sulfur exposures

An investigation of the acute respiratory effects of workers exposed to metal working fluids (MWF) was conducted in an automobile parts manufacturing facility. After observing an association between cross-shift decline in forced expiratory volume in the first second (FEV1) and aerosol mass concentration, improved characterization of the exposure was sought through investigation of four elements of a priori interest (Cl, Cr, Ni, S). Of these, only sulfur showed an association with cross-shift FEV1 decrement. The relative risk of 5% cross-shift FEV1 decrement was 2.7 (95% confidence interval = 1.0-6.0) comparing those with > 4.4 micrograms/m3 to those with < 2.5 micrograms/m3 sulfur exposure. Because the concentrations of sulfur in this environment were relatively low and other respiratory irritants were present, sulfur is more likely to be an indicator of more irritating conditions than the sole agent responsible for the observed acute respiratory effects.

Exposure assessment for a field investigation of the acute respiratory effects of metalworking fluids. I. Summary of findings

The exposure assessment summarized here is part of an epidemiologic study of the acute respiratory health effects of metalworking fluid (MF) exposures. Exposures were measured as the inhalable concentrations of the MF aerosol, a variety of metals and elements, and endotoxin as well as the level of culturable bacteria in the aerosol size fraction less than 8 microns. Bulk samples of soluble MFs were tested for pH, mineral and tramp oil fraction, endotoxin, culturable bacteria, and lipopolysaccharide levels. The MF exposed workers had higher geometric mean inhalable aerosol exposures (0.181 mg/m3) than the MF unexposed workers (0.046 mg/m3). The MF exposed workers had higher geometric mean (GM) airborne culturable microbial counts (102 colony-forming units (CFU)/m3 for bacteria < 8 microns) than the unexposed workers (GM = 14 CFU/m3). Among the unexposed, Bacillus was the predominant airborne species, while among the exposed workers, Pseudomonas predominated. Exposed workers also had higher geometric mean airborne endotoxin levels (GM = 7.1 endotoxin units (EU)/m3) than the unexposed workers (GM = 1.9 EU/m3). Elemental concentrations of iron, chlorine, and sulfur were substantially higher among the exposed workers compared to the unexposed workers. For soluble metalworking fluids, the levels of bulk constituents were examined by three categories of time since the machine sump was refilled with fresh MF (< 4 days, 4-21 days, > 21 days). Univariate analyses of percent oil, pH, culturable bacteria, tramp oil percent, endotoxin, or fatty acid levels all showed no statistically significant changes in level over time.

Ionized hypomagnesemia in patients undergoing orthotopic liver transplantation: a complication of citrate intoxication

Using a new ion-selective electrode, plasma concentration of ionized magnesium was measured in nine adult patients undergoing orthotopic liver transplantation. Baseline plasma ionized magnesium (IMg2+) concentration (0.49 +/- 0.07 mmol/L) was slightly below normal values (0.55-0.66 mmol/L, 95% CI): Six patients had ionized hypomagnesemia and two of these had total hypomagnesemia. Ionized IMg2+ concentration progressively decreased during the dissection (0.45 +/- 0.07 mmol/L, p < 0.05) and anhepatic stage (0.38 +/- 0.07 mmol/L, p < 0.05) and returned toward baseline values by 2 hours after graft reperfusion. Plasma ionized calcium levels and acid-base status were maintained within normal limits during surgery. Serum citrate concentration increased during the dissection (0.58 +/- 0.60 mmol/L) and anhepatic stages (1.18 +/- 0.78 mmol/L), the result of transfusion of citrate-rich blood products in the absence of adequate hepatic function, and gradually returned toward baseline values after graft reperfusion. IMg2+ concentration inversely correlated with the plasma citrate concentration (r2 = 0.54). The results of this study demonstrate that ionized hypomagnesemia invariably occurs during liver transplantation and suggest that this derangement may be a clinical concern, because magnesium is an important cofactor for the maintenance of cardiovascular homeostasis. The data further suggest the clinical importance of supplementation with magnesium based on the monitoring of plasma IMg2+ concentration.

Normotest and abnormal prothrombin in liver transplantation

Postoperative changes in coagulation parameters, including the abnormal plasma prothrombin level, were studied in 95 patients who underwent liver transplantation, and the results were compared with the clinical outcome. The patients were classified into four groups: Group I had a satisfactory postoperative course, (n = 76), Group II suffered graft failure or death at 31 days or more after transplantation (n = 9); Group III suffered graft failure or death from 8 to 30 days after transplantation (n = 4); and Group IV suffered graft failure or death within 7 days of transplantation (n = 6). The Normotest, which closely reflected liver graft function, showed an increase immediately after transplantation in Group I, II, and III, but showed a marked decrease in Group IV. In patients with severe acute cellular rejection, the plasma level of abnormal prothrombin (des-gamma-carboxy prothrombin) was compared with the histology of the liver biopsy specimen. When liver graft function was good after orthotopic transplantation, the Normotest value recovered to the normal range of 70% or more. Subsequently, graft function remained good when the des-gamma-carboxy prothrombin level stayed low, whereas acute cellular rejection was indicated by an elevation of des-gamma-carboxy prothrombin was not produced by graft with early failure, the des-gamma-carboxy prothrombin level also remained low. Thus, the Normotest value and the des-gamma-carboxy prothrombin level were both useful parameters for assessing hepatic function and rejection after transplantation.

Serum-ethanol determination: comparison of lactate and lactate dehydrogenase interference in three enzymatic assays

Gas chromatography is considered to be the reference method for ethyl alcohol determination. However, enzymatic ethanol assays have been developed for use in the clinical laboratory by several commercial vendors. Essentially, these assays utilize the oxidation of ethyl alcohol to acetaldehyde with concurrent reduction of nicotinamide adenine dinucleotide (NAD) to NADH while monitoring the increase in absorbance at 340 nm. The increase in absorbance is theoretically proportional to the ethanol concentration in the sample. Previously, several authors reported that increased concentrations of lactate and lactate dehydrogenase (LDH) can cause false-positive results with certain enzymatic ethyl alcohol assays. In the present investigation, we further studied the interference of lactate and LDH in three enzymatic assays. Apparent ethyl alcohol concentrations in serum spiked with lactate and LDH, as well as patient and autopsy samples, were determined by the Syva, Abbott, and Roche enzymatic assays and by gas chromatography. The effect of coenzyme depletion on the rate of reaction and the interference of hemolysis were also investigated. Based on our results we suggest that coenzyme depletion plays a major role in the severity of the false-positive ethyl alcohol result, and the interference from hemolysis has a negligible effect on these results. We also confirm the previous studies in showing that elevated serum-lactate and LDH concentrations can result in varying degrees of false-positive ethyl alcohol concentrations in the three enzymatic assays. This should be taken into consideration in the management of patients in a tertiary care medical center.

Role of serum markers for liver function and liver regeneration in the management of chloroform poisoning

Accidental or intentional chloroform poisoning is rare, but a few such cases have been reported in literature. We report here a successful management of acute chloroform toxicity in a 33-year-old white female who attempted suicide by injecting one half milliliter of chloroform, followed by drinking half a cup the next morning. Plasma chloroform levels, measured by headspace gas chromatography declined rapidly. Sequential measurement of biomarkers in serum for liver cell necrosis, liver function, and liver regeneration indicated the presence of initial liver damage followed by recovery. These results suggest that in addition to biomarkers for liver cell necrosis, serial determinations of markers for liver regeneration provide objective evidence for recovery from chloroform poisoning and possibly other hepatotoxins.

Plasminogen activator and its inhibitor in cancer patients treated with tumor necrosis factor

BACKGROUND

We noted the presence of plasma fibrin degradation products in patients treated with recombinant human tumor necrosis factor (TNF) in a phase I trial.

PURPOSE

To further define this observation, we investigated the effects of TNF on the fibrinolytic system in patients entered in the same trial.

METHODS

In the 14 patients studied, fibrinolytic parameters were measured by analyzing blood samples for tissue plasminogen activator and inhibitor at 0, 1, 2, 4, 6, and 18-24 hours after initiation of TNF treatment. We used a chromogenic substrate method to determine activity of plasminogen activator and its inhibitor and an enzyme-linked immunosorbent assay (ELISA) to determine levels of antigen (tissue-type plasminogen activator). Molecular weight was determined by zymographic assay.

RESULTS

TNF treatment was associated with tissue-type plasminogen activator induction within 1 hour of TNF initiation. The plasminogen activator produced was consistent with tissue-type plasminogen activator derived from endothelium as evidenced by molecular weight analysis and ELISA. Moreover, induction of plasminogen activator inhibitor occurred following the release of tissue-type plasminogen activator, and our data suggest a dose-response effect for TNF. At high doses (i.e., 200 and 240 micrograms/m2), there was a more rapid and prolonged release of plasminogen activator inhibitor, which had an inverse relationship with the level of antigenic tissue-type plasminogen activator. Zymographic analysis showed urokinase-type plasminogen activator activity in 13 of 14 patients. In three patients, simultaneous measurements of white blood cells and tissue-type plasminogen activator revealed a temporal association between the TNF-associated rapid granulocytopenia at 30 minutes after TNF initiation and release of tissue-type plasminogen activator antigen.

CONCLUSIONS

The results suggest a positive association between TNF and rapid induction of plasminogen activator activity that is consistent with an endothelial product. It is possible that, at high doses, TNF may interact directly with vascular endothelium, leading to rapid and prolonged production of plasminogen activator inhibitor. There was a dose-response effect between TNF and release of tissue-type plasminogen activator. The release of tissue-type plasminogen activator was preceded by granulocytopenia, which may indicate an association between a proposed TNF-induced granulocyte-endothelial interaction in vivo and release of tissue-type plasminogen activator.

IMPLICATIONS

These findings demonstrating the effects of TNF on the fibrinolytic system can be analyzed further in experimental systems to determine the implications for use of this agent as a biological response modifier in cancer therapy.

Enhancement of cell production in long-term bone marrow culture

In an effort to increase the long-term production of hematopoietic cells in vitro, Origen hybridoma cloning factor (HCF) was added at the initiation of Dexter type cultures, in which whole bone marrow (BM) was seeded into tissue culture flasks and formed an adherent stromal layer that supported the proliferation and differentiation of primitive cells. After about six weeks, all the cultures were fully established, and continuous production of nonadherent cells was maintained for at least 27 weeks. In the groups with 20% HCF, there was a significant (three- to fourfold) increase in the steady-state cell production of 106 +/- 17 x 10(4) cells/ml compared to 26 +/- 10 x 10(4) in controls. In some cases the ability of HCF to increase productivity was limited by the nutrients and metabolic products in the culture medium. Cell number varied inversely with glucose and pH. HCF increased the concentration and absolute number of myeloid progenitors (granulocyte-macrophage colony forming units and spleen colony forming units) in the nonadherent layer and shifted the differentiation of granulocyte-macrophage colony forming units toward the production of cells of the monocyte/macrophage lineage. Spleen colonies produced from 10(5) cells from cultures with HCF were more numerous (8 +/- 2 versus 4 +/- 2) and larger than those from control cultures (2.6 versus 0.2 mg/colony), but they contained the usual cell lineages (erythrocytic, granulocytic and megakaryocytic).

Effect of chronic undernutrition on hepatocyte insulin receptors in rats

The effect of moderate chronic undernutrition on insulin receptors was studied in male rats, pair-fed 60% of the daily food intake of ad libitum-fed littermates, for 8 weeks. Body weights of undernourished rats were consistently found to be 35% to 40% less than control littermates, with no period of growth arrest at any point in the 8-week study. The binding-displacement curves of labeled insulin to hepatocyte receptors in the two groups in the presence of unlabeled insulin were significantly different (P = .0258 after repeated measures ANOVA). Significantly lower binding was observed in hepatocytes from the undernourished group (P less than .01) at all unlabeled insulin concentrations less than 20 nmol/L. In the absence of any unlabeled insulin, specific binding was reduced from 8.8% +/- 0.7%, (mean +/- SE) in controls, to 7.4% +/- 0.3% in undernourished rats (P less than .01). Half-maximal specific hormone binding to hepatocytes was achieved at a free insulin concentration of 362 nmol/L in the control group, compared with 447 nmol/L in the undernourished group, reflecting an increase of approximately 20%. The hypoglycemic response to intravenous insulin (0.1 U/kg body weight) was tested in a parallel experiment involving seven paired littermate rats, and found to be significantly impaired in the undernourished group (P = .0041 by repeated measures ANOVA).(ABSTRACT TRUNCATED AT 250 WORDS)

Ionization and hemodynamic effects of calcium chloride and calcium gluconate in the absence of hepatic function

Serial serum ionized calcium concentrations were measured before and after administration of either calcium chloride or calcium gluconate during the anhepatic stage of liver transplantation in 15 patients to determine the release of ionized calcium in the absence of hepatic function. When hypocalcemia (Ca++ less than 0.8 mM) occurred during the anhepatic stage, patients were randomly assigned to treatment with chemically equivalent doses of either calcium chloride (10 mg/kg, n = 8) or calcium gluconate (30 mg/kg, n = 7). Serum concentrations of ionized calcium and citrate, hematocrit, arterial blood gas tensions, acid-base state, and hemodynamic profiles were determined before and up to 10 min after calcium therapy. In both groups of patients initial similar and rapid increases in Ca++ (0.98 +/- 0.14 mM in the calcium chloride group and 1.05 +/- 0.10 mM in the calcium gluconate group) were followed by gradual decreases over the next 10 min. Measured hemodynamic values were similar in the two groups, and neither group showed improvement in cardiovascular function after calcium therapy, possibly because of the decrease in preload that occurred during the anhepatic stage. Equally rapid increases in Ca++ after administration of calcium chloride and gluconate in the anhepatic state suggest that calcium gluconate does not require hepatic metabolism for the release of Ca++ and is as effective as calcium chloride in treating ionic hypocalcemia in the absence of hepatic function.

The effect of menhaden oil on choline-deficiency-induced hepatic ornithine decarboxylase activity and hepatocyte insulin receptor binding

The effects of menhaden oil on the choline-deficient (CD) diet tumor promotion regimen-induced alterations in hepatocyte insulin receptors and the cellular ornithine decarboxylase (ODC) activity have been investigated in this study. Male Sprague-Dawley rats exposed to the tumor-promoting regimen of a CD diet for 10 days showed increases in hepatic ODC activity from 2.68 +/- 0.42 pmol 14CO2/mg protein/h in the animals fed basal control chow (C) to 13.54 +/- 2.38 (P less than 0.02) in the rats fed CD diet. These changes in ODC occur simultaneously with the alterations in hormone receptor binding as reported previously for insulin. Replacement of the lipid present in the control diet with 15% menhaden oil (CMO) had no significant effect on ODC activity (0.91 +/- 0.21), or on the number of insulin receptors (206,000 +/- 37,000) and the Kd (7.4 +/- 1.6). Sequential treatment with 10 days of CD diet and then 10 days of the C diet, resulted in a reversal in the elevated, CD-induced hepatic ODC activity to the control levels; however, substituting 15% menhaden oil for the fat present in the CD diet (CDMO) enhanced this enzymatic activity. In contrast, both sequential and CDMO treatments prevented the insulin receptor alterations induced by the CD diet. These data demonstrate that the CD diet-induced insulin receptor alterations occur concurrently with the induction of ODC activity. But insulin receptor changes and the increased ODC activity are affected differently by CDMO treatment, suggesting that their induction by the CD diet is through distinct mechanisms and only the receptor alterations correspond with the tumor-promoting action of CD diet regimen.

Hypoaminoacidemia caused by imipramine but not by clenbuterol is dissociable from hyperglycemia and hyperinsulinemia

The effects of the tricyclic antidepressant imipramine (20 mg/kg) and the beta-adrenoceptor agonist clenbuterol (0.5 mg/kg) on the serum concentrations of tyrosine, tryptophan, glucose and insulin were compared 30 min after intraperitoneal injection. The drugs had nearly identical effects on serum tyrosine, which was reduced to 73% of control by both drugs, and on tryptophan, which was reduced to 72% by imipramine and to 66% by clenbuterol. In contrast, whereas clenbuterol raised serum glucose to 174% and insulin to 379% of control, imipramine had no significant effects on either glucose or insulin. The results clearly demonstrate that the effects of imipramine on blood amino acid levels are dissociable from effects on glucose and insulin. We conclude, therefore, that hypoaminoacidemia caused by imipramine is not mediated by stimulating insulin release.

Alterations induced by phenobarbital, a liver tumor promoter, in hepatocyte receptors for insulin and glucagon and glycogen metabolism

Exposure of rats to phenobarbital (PB), a tumor promoter in the two-stage hepatocarcinogenesis model, in their diet (0.06%) induces alterations in insulin receptors in the hepatocytes. There is a decrease both in the number of receptors and the dissociation constant (Kd) when compared with animals fed control laboratory diet. The number of insulin receptors/cell and the Kd were respectively: 183,000 +/- 19,000 and 15.3 +/- 2.5 nM for controls; 47,000 +/- 5000 and 2.8 +/- 0.3 nM for PB. The glycogen synthesis in response to insulin was found to be unresponsive in the hepatocytes from rats exposed to PB. Glucagon receptors on hepatocytes, however, were unaltered in animals treated with PB or fed a choline-deficient (CD) diet and the glucagon-stimulated glycogenolytic responses were also comparable to the controls. There is, therefore, a selective alteration in the hepatocyte surface membrane receptors. Both PB and CD have been shown to reduce the hepatic cell membrane receptors for epidermal growth factor, indicating that the two different tumor promoters alter peptide receptors with endogenous protein kinase activities. This similar though selective effect of the tumor promoters on cell surface receptors may be of significance in their action in carcinogenesis by having an effect on the alteration of regulation of cell growth and metabolism.

Modulation of epidermal growth factor receptors in rat hepatocytes by two liver tumor-promoting regimens, a choline-deficient and a phenobarbital diet

The effect of two liver tumor-promoting regimens, a choline-deficient (CD) and a phenobarbital (.06% PB) diet, on the level of epidermal growth factor (EGF) receptor in rat hepatocytes was examined at 3, 10, and 28 days of feeding. Both diets produced a significant decrease in the number of cell surface receptors at 10 and 28 days of treatment. When PB was included in a CD diet, the decrease in the receptor number was evident even after 3 days feeding of the combined diet. Neither diet alone had any effect on the binding at that time. Along with the changes in the receptor number, the binding affinity of EGF to its receptor was also altered by these diets. Furthermore, PB and PB plus CD diets also decreased the EGF binding at the intracellular sites whereas CD diet showed no effects indicating that the decrease in surface binding of EGF by the promoter-treated hepatocytes was not due to rapid internalization of the receptors. The reduced level of hepatocyte surface EGF receptors represents the common property shared by two diverse types of the liver tumor promoters, and may thus be related to the tumor-promoting ability of these agents.

Selective secretion of only the urokinase plasminogen activator from rat islets of Langerhans

Rat islets of Langerhans produce plasminogen activators (PA). The islet level of PA and the enzyme secreted in the islet incubation medium, are regulated by agents which modulate insulin synthesis and release. The cellular PA activity is due to 2 molecular forms of the enzyme, a Mr 72,000 and a Mr 48,000 species found in almost equal proportions. But the enzyme activity in the medium is due to only the lower molecular weight form. It is shown that this enzyme activity in the medium is due to immunologically identifiable urokinase type PA (uPA) and the cellular enzyme activity is due to both, uPA and tissue-type PA (tPA).

Free radical injury and liver tumor promotion

One of the underlying mechanisms of tumor promotion both in the skin and liver involves free radical mediated injury to informational macromolecules of target cells. A choline-deficient (CD) diet, which is an efficient liver tumor promoter, induces peroxidative damage of liver cell membrane lipids. By modifying components of a CD diet, we have shown that the efficacy of the promotion is correlated with the extent of lipid peroxidation. The substitution of fats in a CD diet with predominantly polyunsaturated fat and the addition of methapyrilene to a CD diet enhances membrane lipid peroxidation and the promoting effects. An antioxidant (BHT) and hypolipidemic peroxisome proliferators (BR931 and DEHP) suppress both of these effects. Contrary to these findings, phenobarbital did not induce membrane lipid peroxidation, and its addition to a CD diet inhibited the diet-induced lipid peroxidation, though such a combination exerted a stronger promoting action. Thus, a CD diet and phenobarbital exert their promoting actions through different mechanisms. The consequence of membrane lipid peroxidation in the liver cells induced by a CD diet may be multiple. Our recent study of surface membrane insulin receptors of liver cells of rats fed a CD diet showed a decrease in number and an enhanced binding affinity leading to altered responsiveness of liver cells to insulin mediated glycogen synthesis. It is suggested that CD diet-induced lipid peroxidation leads to functional alterations of membrane receptors involved in cell growth control and may thereby exert its promoting action.

Cardiovascular depression secondary to ionic hypocalcemia during hepatic transplantation in humans

Cardiovascular function, serum ionized calcium (Ca+2), and serum citrate were measured intraoperatively in patients (n = 9) undergoing orthotopic hepatic homotransplantation. Serum citrate increased 20-fold (P less than 0.0006) following transfusion of citrated blood products in the absence of a functional liver. Serum ionized calcium decreased (P less than 0.003) with concomitant decreases in cardiac index (P less than 0.005), stroke index (P less than 0.004), and left ventricular stroke work index (P less than 0.001). Hemodynamic depression and ionic hypocalcemia were reversed following the administration of CaCl2. In contrast to patients with normal hepatic function, who may tolerate large amounts of citrated blood, patients with end-stage liver disease demonstrate acute ionic hypocalcemia with concomitant hemodynamic depression when receiving citrated blood products during the course of hepatic transplantation.

Presence of complement-dependent cytotoxic activity against clonally-derived rat islet tumour cells in sera from type 1 (insulin-dependent) diabetic patients and control subjects

Heat-inactivated sera from newly diagnosed Type 1 (insulin-dependent) diabetic patients and control subjects were tested for the presence of antibodies to islet cell surface antigens by means of a sensitive immunofluorescent, microcytotoxicity assay using two clones of a rat islet cell tumour as antigens. Complement-dependent cytotoxicity was found in 74% of diabetic patient sera and 87% of control sera, and there were no significant differences in titres between diabetic patients and control subjects. A minority of the sera from both patients and controls were cytotoxic for only one of the two clones, suggesting the presence of multiple antigen-antibody systems. Preadsorptions of the sera with rat liver powder, sheep erythrocytes, and/or protein A-conjugated agarose beads were inconsistently effective in decreasing levels of lytic activity in control sera. It is concluded that more information is required concerning the antigens of rat islet cells and islet cell cytotoxic factors present in normal sera before such cells and assays can be reliably used for the detection of islet cell surface antibodies.

Alterations in hepatocyte insulin receptors in rats fed a choline-deficient diet

Specific insulin binding and glycogen synthesis were studied in control hepatocytes, hepatocytes from rats fed a choline-deficient (CD) diet for 7 to 14 days, and hepatoma cells induced with a CD diet and DL-ethionine in culture. Both the binding affinity and the number of receptors were affected in hepatocytes by the CD diet. The number of receptor sites was 26,000/cell and the dissociation constant (Kd) for the high affinity binding site was 2.6 nM at 30 degrees C, in contrast to the control values of 205,000 sites/cell and 23.2 nM, respectively. In the hepatoma cells, receptor cell number and Kd were further diminished to 6,400 sites/cell and Kd = 1.1 nM. The basal level of glycogen synthesis in control hepatocytes and in CD hepatocytes was similar; however, the basal rate of glycogen synthesis in hepatoma cells was only 16% of that in the control cells. The glycogen synthesis in hepatoma cells was stimulated by insulin, but at a 3-log higher concentration compared to the control cells. This loss of sensitivity to insulin is consistent with the marked decrease in insulin receptors. CD hepatocytes had a decrease in insulin receptors with a concurrent decrease in Kd (increase in binding affinity), such that, sensitivity to insulin did not differ significantly from that of control hepatocytes. However, the maximal stimulation of glycogen synthesis was only 27% that of the control cells. The changes in receptor number and Kd of hepatocytes from rats fed a CD diet may be due to alterations in cell membrane lipid composition and this alteration may be responsible for the enhanced sensitivity of hepatocytes to chemical carcinogens and for the tumor promoting effect of the diet.

Circulating prostatic acid phosphatase-immunoglobulin complexes in Sjogren's syndrome

Elevated level of serum prostatic acid phosphatase (PAP) activity in a patient with Sjogren's syndrome was found to be due to the presence of PAP-immunoglobulin complexes in circulation. The patient did not have a prostatic malignancy. The complexes were demonstrated by counter-immunoelectrophoresis, protein A-Sepharose immunoprecipitation and agarose-gel electrophoresis. Free enzyme was not detected in serum, and the activity of the complexed enzyme was probably unaltered on binding with the immunoglobulins.

Hormone-induced actin polymerization in rat hepatoma cells and human leucocytes

Treatment of rat hepatoma cells with insulin, glucagon, thyroxine (T4) and triiodothyronine (T3) caused a concentration-dependent decrease in the monomeric actin content as measured by the deoxyribonuclease-I inhibition assay. Similarly, human peripheral blood neutrophils responded with a decrease in monomeric actin content when stimulated with T4, T3 and the adrenergic agonists phenylephrine and isoprenaline. The effect of phenylephrine could be blocked by phentolamine, demonstrating the specificity of the interaction. These observations suggest that hormone-induced actin changes might be an important event in response to both cell-surface-reactive hormones, such as insulin, glucagon and adrenergic agents, and those hormones that act through intracellular receptors, such as thyroid hormones. It is suggested that changes in actin state may have a role in metabolic regulation and cell growth.