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This guide to producing optimum bump tubing reports recent technology developments. Once deemed to be a "black art" the tube manufacturing process has evolved into being a validatable process.

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When extruding medical tubing, process engineers are faced with many decisions each time a different size, configuration or material is specified for a new product. Sizing is the final forming of a tube to specified dimensions. Three sizing methods are evaluated for optimum tubing production.

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Insulin pens deliver insulin more slowly than syringes because of compressible elements of the insulin cartridges, especially air bubbles. The time required for a pen to deliver 20 Units of insulin increased with increasing air in the cartridge as determined by two independent techniques. The first technique involved no back pressure and was done by injection of [125I]-iodoinsulin onto absorbent paper on a constant angular velocity turntable. The second technique involved the normal back pressure of subcutaneous tissue and was done by robotic, timed injections of [125I]-iodoinsulin into full thickness pigskin. Air dramatically reduced the delivery of insulin in the five seconds that patients normally wait for injection by an insulin pen. Accumulation of more than 50 microliters of air results in a delivery of an unacceptably low percentage of insulin: with 200 microliters of air, a patient would get only 37% of the expected dose. Thus, a patient who injects 20 Units of insulin and withdraws the needle after the recommended 5 seconds would receive only 7.4 Units if there were 200 microliters of air in the cartridge. Since we found that 42 of 50 commercially available insulin cartridges contained air bubbles at purchase (average estimated to be 50 microliters), additional air entering the cartridge could lead to serious underdosing. Previous studies have demonstrated that air accumulates in insulin cartridges when the needle is left on the pen between injections. Therefore, for safety reasons, patients should be strongly advised to remove the needle immediately after each injection as recommended by the manufacturer.

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A modified method for the derivatization and determination of acrylamide as 2-bromopropenamide by gas chromatography-electron-capture detection was developed and applied to serum and sciatic nerve from rats. The method was accurate and precise over the calibration range 2.24-7.47 micrograms/ml in serum diluted 1:125 and 4-122 micrograms/g in sciatic nerve homogenate (5 mg/ml). limits of detection were estimated to be 1200 ng/ml in undiluted serum and 3 micrograms/g in intact sciatic nerve. The use of less dilute samples to allow for lower limits of detection appears feasible. The time-course of acrylamide in serum and sciatic nerve was studied after acute dosing and indicated elimination half-lives of 1.8 and 2.0 h for serum and sciatic nerve, respectively. A dose-effect relationship was established for each matrix after acute dosing and the measured acrylamide concentrations in serum (microgram/ml) were approximately the same as in sciatic nerve (microgram/g).

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EPA's TEAM Study has measured exposures to 20 volatile organic compounds in personal air, outdoor air, drinking water, and breath of approximately 400 residents of New Jersey, North Carolina, and North Dakota. All residents were selected by a probability sampling scheme to represent 128,000 inhabitants of Elizabeth and Bayonne, New Jersey, 131,000 residents of Greensboro, North Carolina, and 7000 residents of Devils Lake, North Dakota. Participants carried a personal monitor to collect two 12-hr air samples and gave a breath sample at the end of the day. Two consecutive 12-hr outdoor air samples were also collected on identical Tenax cartridges in the backyards of some of the participants. About 5000 samples were collected, of which 1500 were quality control samples. Ten compounds were often present in personal air and breath samples at all locations. Personal exposures were consistently higher than outdoor concentrations for these chemicals and were sometimes 10 times the outdoor concentrations. Indoor sources appeared to be responsible for much of the difference. Breath concentrations also often exceeded outdoor concentrations and correlated more strongly with personal exposures than with outdoor concentrations. Some activities (smoking, visiting dry cleaners or service stations) and occupations (chemical, paint, and plastics plants) were associated with significantly elevated exposures and breath levels for certain toxic chemicals. Homes with smokers had significantly increased benzene and styrene levels in indoor air. Residence near major point sources did not affect exposure.

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Twenty volatile organic compounds were measured in the personal air and drinking water of 350 New Jersey residents in the fall of 1981. Two consecutive 12-hour integrated personal air samples and two tap water samples were collected from each participant. At the end of the 24-hour monitoring period, each participant supplied a sample of exhaled breath. Simultaneous outdoor samples were collected in 100 residential locations in two cities. Eleven compounds were present much of the time in air, but only four (the trihalomethanes) in water; wide ranges of exposures (three to four orders of magnitude) were noted for most compounds. Ten of 11 compounds displayed significant correlations between air exposures and breath concentrations; the 11th (chloroform) was correlated with drinking water exposures. It was concluded that breath measurements are a feasible, cost-effective, and highly sensitive way to determine environmental and occupational exposures to volatile organic compounds.

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This paper reports the characterization of the extractable organics from diesel particulate emissions compared to other complex organics which have been reported to increase the risk of human lung cancer. Class fractions of diesel, cigarette smoke condensate, roofing tar, and coke oven extracts were obtained using liquid/liquid partitioning and silica gel chromatography. Capillary GC/MS was used to identify compounds in each extract fraction. This manuscript reports the mass distribution after fractionation of each extract, all identified fraction components and quantification of selected mutagenic and carcinogenic compounds.

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A sensitive and specific high-performance liquid chromatographic (HPLC) assay was developed for the determination of the candidate antimalarial (+/-)-(1,3-dichloro-6-trifluoromethyl-9-phenanthryl)-3-di-(n-butyl )aminopropanol hydrochloride in whole blood. A reversed-phase, paired-ion (lauryl sulfate) system achieved separation of the antimalarial and internal standard from interfering constituents with a sensitivity limit of 10 ng/mL by UV detection (254 nm). Chromatographic variables (counterion concentration, pH, and column temperature) were examined to determine their effect on assay characteristics (retention, efficiency, and relative response) in clinical analysis. The antimalarial was isolated from 2.0 mL of whole blood using overnight extraction with 30% ethyl acetate in hexane followed by an acid/base partition sequence to remove major interferences. Overall recovery for the antimalarial was 84% with a CV of 5.0%, and the recovery of the internal standard was 81% (CV = 3.6%). The assay was validated by analysis of both intra- and interlaboratory samples. The assay was applied to the analysis of whole blood samples taken from a 30-year-old healthy human male who had received a single 14.1-mg/kg oral dose. The stability of the antimalarial in whole blood for up to 4 months and in sample extracts for up to 34 d at -17 degrees C was also demonstrated.

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Mirex is an organochlorine chemical with pesticidal and other industrial usages. Biologically, mirex was used as an insecticide for the control of imported fire ants in large areas of the southeastern United States. Evidence of mirex exposure in a national survey of chemicals in adipose tissue led to a more intensive survey of the general population in treated counties of the southeastern United States. Forty sites were selected randomly from 8 southeastern states where mirex was used widescale to combat fire ants; a total of 624 adipose tissue specimens were collected from these 40 sites. Tissue specimens were prepared by a modified Mills-Onley-Gather procedure and analyzed for mirex and selected other organochlorine compounds by electron-capture gas chromatography. Positive residue findings were confirmed by combined gas chromatography and mass spectrometry. Weighted statistical analysis of the data was conducted to estimate the level of mirex in the study area. It was estimated that 10.2% of the population of southern United States had quantifiable levels of mirex in adipose tissue. The estimated geometric mean of the quantifiable residue amounts was 0.286 ppm (lipid basis). Statistical tests of association and regression were used to investigate possible relationships between the presence and levels of mirex, and the Census Division or state of tissue-specimen collection, by age, race, and sex. These analyses indicated that region or location of tissue specimen collection (assumed to be area of residence) strongly related to both the presence of mirex residue and the amount of mirex residue detected. This may be correlated with the amount of mirex applied for fire ant control or with some other exposure patterns in different regions.

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A pilot study to test methods of estimating personal exposures to toxic substances and corresponding body burdens was carried out between July and December 1980. Individual exposures to about a dozen volatile organic compounds in air and drinking water were measured for nine volunteers in Bayonne and Elizabeth, New Jersey, and for three volunteers in Research Triangle Park, North Carolina during three 3-day visits over the 6-month period. Breath samples were also collected from all subjects on each visit. Composite food samples were collected in each locality. Sampling and analytical methods for air, water, food, and breath were evaluated and found generally capable of detecting concentrations as low as 1 microgram/m3 in air and breath, and 1 ng/g in water and food. About 230 personal air samples, 170 drinking water samples, 66 breath samples, and 4 food samples (16 composites) were analyzed for the target chemicals. Ten compounds were present in air and eight were transmitted mainly through that medium. The two target trihalomethanes (chloroform and bromodichloromethane) were predominantly transmitted through water and beverages. Food appeared to be a minor route of exposure, except possibly for trichloroethylene in margarine. Seven compounds were present in more than half of the breath samples. Diurnal and seasonal variations were noted in air and water concentrations of some compounds, with summer levels generally higher. For some chemicals, weekday air exposures were significantly higher than weekend exposures. Some, but not all, of the potentially occupationally exposed individuals had significantly higher workplace exposures to several chemicals. Distributions of air exposures were closer to log normal than normal for most chemicals. Several chemicals were highly correlated with each other in personal air samples, indicating possible common sources of exposure.

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