Tissue-engineered cartilage and bone using stem cells from human infrapatellar fat pads.

Multipotential processed lipoaspirate (PLA) cells extracted from five human infrapatellar fat pads and embedded into fibrin glue nodules, were induced into the chondrogenic phenotype using chondrogenic media. The remaining cells were placed in osteogenic media and were transfected with an adenovirus carrying the cDNA for bone morphogenetic protein-2 (BMP-2). We evaluated the tissue-engineered cartilage and bone using in vitro techniques and by placing cells into the hind legs of five severe combined immunodeficient mice. After six weeks, radiological and histological analysis indicated that the PLA cells induced into the chondrogenic phenotype had the histological appearance of hyaline cartilage. Cells transfected with the BMP-2 gene media produced abundant bone, which was beginning to establish a marrow cavity. Tissue-engineered cartilage and bone from infrapatellar fat pads may prove to be useful for the treatment of osteochondral defects.

Evaluation of a real-time passive personal particle monitor in fixed site residential indoor and ambient measurements.

Recent experimental findings in animals and humans indicate adverse respiratory effects from short-term exposures to particulate air pollutants, especially in sensitive subpopulations such as asthmatics. The relationship between air pollution and asthma has mainly been determined using particulate matter (PM) measurements from central sites. Validated tools are needed to assess exposures most relevant to health effects. Recently, a personal passive particulate sampler (personal Data-RAM, pDR, MIE Inc., Bedford, MA) has become available for studying personal exposures to PM with time resolution at 1 min. The pDR measures light scatter from PM in the 0.1-10 microM range, the significant range for health effects. In order to assess the ability of the pDR in predicting gravimetric mass, pDRs were collocated with PM2.5 and PM10 Harvard Impactors (HI) inside and outside nine homes of asthmatic children and at an outdoor central Air Pollution Control District site. Results are presented of comparisons between the HI samplers and the pDR in various modes of operation: passive, active, and active with a heated inlet. When used outdoors at fixed sites the pDR readings exhibit interference from high relative humidity (RH) unless operated with a method for drying inlet air such as a heater, or if readings at times of high RH are adjusted. The pDR correlates more highly with the HI PM2.5 than with the HI PM10 (r2 = 0.66 vs. 0.13 for outdoors, r2 = 0.42 vs. 0.20 for indoors). The pDR appears to be a useful tool for an epidemiologic study that aims to examine the relationship between health outcomes and personal exposure to peaks in PM.

Occupational needlestick injuries in a metropolitan police force.

OBJECTIVES: Police officers are at risk of bloodborne diseases through needlestick injuries but few studies have addressed this problem. The purpose of this study was to assess the risk of needlestick injuries in law enforcement officers and to determine predictors of injuries and reporting rates. DESIGN: An anonymous, voluntary questionnaire was distributed to 1738 active-duty, metropolitan police officers. The survey included the number of needlestick injuries ever experienced, how often these were reported, activities at the time of injury and attitudes toward injuries. RESULTS: Of the 803 respondents (46.2% of survey population), 29.7% had at least one needlestick injury, and 27.7% of this group had two or more. Risk factors included evening shifts, pat-down searches, patrol duties, male gender and less experience. Only 39.2% sought medical attention for these injuries. CONCLUSIONS: Needlestick injuries occur with considerable frequency in this group of law enforcement personnel, suggesting an increased risk of becoming infected with bloodborne pathogens, including hepatitis B, hepatitis C and HIV.

Detection of Mycoplasma genus and Mycoplasma fermentans by PCR in patients with Chronic Fatigue Syndrome.

Mycoplasma fermentans and other Mycoplasma species are colonizers of human mucosal surfaces and may be associated with human immunodeficiency virus infection. While many infectious agents have been described in different percentages of patients with Chronic Fatigue Syndrome (CFS), little is known about the prevalence of mycoplasmas and especially M. fermentans in CFS patients. A polymerase chain reaction (PCR)-based assay was used to detect Mycoplasma genus and M. fermentans genomes in peripheral blood mononuclear cells (PBMC) of CFS patients. Blood was collected from 100 patients with CFS and 50 control subjects. The amplified products of 717 bp of Mycoplasma genus, and 206 bp of M. fermentans were detected in DNA purified from blood samples in 52% and 34% of CFS samples, respectively. In contrast, these genomes were found in only 14% and 8% of healthy control subjects respectively (P < 0.0001). All samples were confirmed by Southern blot with a specific probe based on internal sequences of the expected amplification product. Several samples, which were positive for Mycoplasma genus, were negative for M. fermentans indicating that other Mycoplasma species are involved. A quantitative PCR was developed to determine the number of M. fermentans genome copies present in 1 microg of DNA for controls and CFS patients. Mycoplasma copy numbers ranging from 130 to 880 and from 264 to 2400 were detected in controls and CFS positive subjects, respectively. An enzyme immunoassay was applied for the detection of antibodies against p29 surface lipoprotein of M. fermentans to determine the relationship between M. fermentans genome copy numbers and antibody levels. Individuals with high genome copy numbers exhibited higher IgG and IgM antibodies against M. fermentans specific peptides. Isolation of this organism by culture from clinical specimens is needed in order to demonstrate specificity of signal detected by PCR in this study.

Fetal effects of inhalation exposure to cyclohexanone vapor in pregnant rats.

Cyclohexanone (CH), a solvent and thinner that has extensive use in industry, was investigated for developmental effects using pregnant Sprague-Dawley rats exposed to 100, 250 or 500 ppm concentrations in an inhalation chamber for seven hours per day from days 5 through 20 of pregnancy. Controls were exposed to room air. Maternal weight gain at 250 and 500 ppm CH was only slightly lower than in the control dams, and a grey mottling of the lungs was seen in a few of the CH-exposed dams. There were no significant differences between the CH and control groups in fetal weight, resorption sites, fetal death or sex ratio. External and soft tissue examinations revealed no significant incidence of malformations or variations in CH-exposed animals. A slight increase in the mean percent of rudimentary ribs per litter was observed in the 250 and 500 ppm CH-exposed groups. However, no significant numbers of skeletal malformations were noticed in either the CH or room air control groups. It was concluded that respiratory exposure of rats to as much as 500 ppm CH during organogenesis was unlikely to be developmentally toxic.

Exposure of acrylic fingernail sculptors to organic vapors and methacrylate dusts.

Personal and area samples for organic vapors and polymethacrylate dust were collected in six different sculptured nail salons. Self-administered symptom questionnaires were completed by 20 female nail sculptors and 20 matched controls. Mean time-weighted average concentrations (TWACs) of ethyl methacrylate, isopropyl alcohol, butyl acetate and toluene in 17 personal organic vapors samples collected in these establishments were 4.5, 15.6, 0.4 and 0.8 ppm, respectively. The mean TWACs of polymethacrylate dust in 16 personal samples were 0.9 mg/m3 and 1.4 mg/m3 for respirable dust and total dust, respectively. The only statistically significant (p less than .05) health effect noted among sculptors was throat irritation. Also, nose and skin irritation, drowziness, dizzy spells and trembling of the hands were reported consistently more often by sculptors than the control group; however, the difference was not statistically significant.

Laboratory evaluation of RDM-201 Respirable Dust Monitor.

The current paper discusses the results of laboratory experiments conducted to evaluate the GCA Respirable Dust Monitor RDM-201 in comparison with the standard Gravimetric Respirable Dust Sampler (GRDS). The samplers were compared in parallel within the atmosphere of an inhalation chamber laden with Arizona Fine Road Dust (AFRD). A wide range of dust concentrations (i.e., from 0.17 to 32:81 mg/m3) was used in the experiments. Sampling time varied from 15 to 120 min. There was a high agreement between the two GRDSs, particularly for samples with dust weight larger than 0.5 mg. The correlation and linearity between the RDM-201 display reading and the actual weight of dust on the instrument's filter were quite high for dust samples larger than 0.5 mg, but dropped significantly for samples less than 0.5 mg. Considering the extremely high dust concentration required to collect a minimum of 0.5 mg of respirable dust within 1-min sampling time of the RDM-201's automatic sampling mode, it was concluded that the use of automatic mode intended for quick evaluation of dusty atmosphere is impractical under most ordinary dusty conditions. The RDM-201 manual mode can be used, however, as reliably as a GRDS, for extended sampling times for assessment of TWAC of respirable dust in the atmosphere of a workplace, providing that a minimum of 0.5 mg sample is collected on the filter.

Monitoring of workers exposure to low levels of airborne monomers in a polystyrene production plant.

Exposure of workers to sub-ppm levels of airborne monomers, namely ethyl acrylate, methyl methacrylate, n-butyl acrylate, styrene, alpha-methylstyrene, and 2-ethylhexyl acrylate, in a polystyrene production plant was measured in the same sample on a single gas chromatographic column. The best separation and sensitivity were obtained with a 3 m X 3.175 mm stainless steel column packed with 10% FFAP on Chromosorb and a temperature programmed from 70 degrees C to 110 degrees C. A total of 106 air samples were collected on 150 mg charcoal tubes from the breathing zone of workers, from areas near reactors, and from places where monomers were unloaded from trucks and tank cars. Samples were analyzed in a manner similar to the method recommended by NIOSH. The mean TWA concentrations in a worker's breathing zone were 89, 66, 49, 120, 41 and 1 ppb for ethyl acrylate, methyl methacrylate, n-butyl acrylate, styrene, alpha-methylstyrene, and 2-ethylhexyl acrylate, respectively. The highest TWA breathing zone concentration was 14.8 ppm for styrene, which occurred during unloading and sampling of the monomer for a quality check. The mean TWA concentration of monomers in the air of the workplace were 1.1 ppm, 169, 36, 54, 10, and 30 ppb for the same 6 compounds mentioned above. The highest area TWA concentration was 57 ppm for ethyl acrylate, which occurred outdoors at the truck and tank car unloading site. It was concluded that use of two separate local exhaust ventilating systems in this polymerization process were effective in maintaining negative pressure within the reactors under all circumstances of use. These engineering controls and care in handling monomers have resulted in a relatively safe working environment.

Exposure to isophorone and other organic solvents in a screen printing plant.

A study was conducted in a screen printing plant to determine the exposure of workers to isophorone and other organic solvents. One hundred twenty-four charcoal tube samples were collected from both workers breathing zones and various workplace areas. Sampling times were 50-90 minutes. Maximum mean TWACs of isophorone and cyclohexanone were 23 +/- 5.4 ppm and 28 +/- 5 ppm, respectively, at the breathing zones of printing press workers. Exposure levels for other organic vapors such as cellosolve acetate, butyl acetate, xylenes, diacetone alchohol, and petroleum distillate are also presented. Mean TWACs of personal samples were generally higher than area samples due to proximity of the solvent evaporating surfaces to the workers breathing zones. Mean TWACs for the individual organic vapors did not exceed OSHA Limits. However, the sum of (TWAC/TLV) ratios of organic vapors with additive health effects exceeded unity at the breathing zones of workers handling inks and solvents. Actual 8-hour worker exposures were assumed to be lower because workers were exposed to lower concentrations (about 9/10 of the additive TLVs) in the plant's general atmosphere during non-active periods of the work shift. Recommendations for improvement of working conditions and reduction of exposure levels are made.

Occupational exposure to asbestos fibers resulting from use of asbestos gloves.

To assess the magnitude of fiber emission from asbestos gloves, 10 pairs were compared in an isolation chamber during simulation of a sterilization procedure; 176 air samples were collected. Means of time weighted average (TWA) concentrations ranged from 0.95 to 11.74 fibers (greater than 5 micrometers)/cm3 of air. Well-worn/clean gloves emitted significantly more fibers than did brand-new gloves, but fiber emission decreased with increased surface soiling. Eighty air samples were collected during simulation of the sterilization procedure in a well-ventilated room. The range of mean TWA concentrations was 0.07-0.99 fiber/cm3 for breathing zone samples and 0.06 to 0.60 fiber/cm3 for area samples. Thirteen samples were collected at actual workplaces; the range of TWA concentrations was 0.07-2.93 fibers/cm3 for breathing zone samples and 0.04-0.74 fiber/cm3 for area samples. Five of seven breathing zone samples from workplaces exceeded the proposed TWA concentration limit of 0.1 asbestos fiber/cm3. Hand contamination also was assessed. Four samples collected after touching the worktable ranged from 9953 to 13 108 fibers (greater than 5 micrometers)/cm2 of hand surface area; seven samples collected immediately after taking off gloves ranged from 741 to 3860 fibers/cm2. Available substitutes for asbestos gloves are discussed, and adoption of these substitutes is recommended strongly.

Adsorption of cyanophage AS-1 to unicellular cyanobacteria and isolation of receptor material from Anacystis nidulans.

Cells of unicellular cyanobacteria of typological group Ia, containing approximately 50 mol% guanine + cytosine (G+C) in their DNA (R. Y. Stanier, R. Kunisawa, M. Mandel, and G. Cohen-Bazire, Bacteriol. Rev. 35:171-205, 1971), were susceptible to infection by the cyanophage AS-1. Cyanobacteria of the same typological group, containing approximately 65 mol% G+C in their DNA, did not adsorb the cyanophage AS-1 or adsorbed it at a low rate. AS-1 was not propagated by any of the investigated strains with a high G+C content in their DNA. However, cells of strains 6907 and 6911 were lysed by cyanophage AS-1. A comparison of the host range of this phage with the lipopolysaccharide composition of host and non-host cell walls suggests that lipopolysaccharides are involved in the adsorption process. About 8 microgram of lipopolysaccharide per ml from host strains inactivated 50% of the particles of a solution containing 100 PFU/ml after 60 min of incubation at 30 degrees C. Material with receptor activity was extracted from the host strain Anacystis nidulans KM. The extract was purified of glycolipids and pigments, and a fraction showing receptor activity was isolated. This fraction contained three polypeptides of molecular weights between 54,000 and 64,000. Heat and protease treatment of whole cells and of isolated receptor material decreased the receptor activity. The fluorescence intensity of A. nidulans cells labeled with 1-anilino-8-naphthalene sulfonate was increased when AS-1 was adsorbed to these cells. The participation of lipopolysaccharides and proteins in the formation of the receptor complex is discussed.

The efficiency of protective hoods used by sandblasters to reduce silica dust exposure.

Several types of respiratory protective hoods used by sandblasters were investigated in two steel fabrication yards. MSA Gravimetric Dust Samplers were used to collect respirable dust samples outside and inside hoods during sandblasting. Colorimetric and x-ray diffraction techniques were applied to the samples for free-silica determination. The majority of the sandblasters, who wore various types of air-supplied hoods, were exposed to an average level of silica dust several times higher than the TLV. Sandblasters wearing non-air-supplied hoods were at the greatest risk. Modern well maintained and properly worn air-supplied hoods offered fair protection during sandblasting periods, but the concentration of suspended respirable dust in ambient air during non-blasting intervals exceeded the TLV by several times.