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At least 163 records · Page 9Linked to original sources
PubMed2005

Use of solid-phase microextraction/gas chromatography-electron capture detection for the determination of energetic chemicals in marine samples.

Gas chromatography with electron capture detection (GC-ECD) is a highly explosive-sensitive analytical technique. However, its application to the analysis of sediment extracts is hampered by the presence of numerous endogenous interferences. In the present study, solid-phase microextraction (SPME) was used both as a purification technique for sediment extracts and as an extraction technique for water samples prior to analysis by GC-ECD. SPME/GC-ECD coupling was optimized and applied to the trace analysis of nine explosives including nitroaromatics and RDX in real seawater and marine sediment samples. Addition of a high concentration of salt (30%, w/v) in the aqueous medium and use of a carbowax/divinylbenzene (CW/DVB) coating led to optimal extraction efficiencies. Method detection limits (MDLs) ranged from 0.05 to 0.81 microg/L in water and from 1 to 9 microg/kg in dry sediment. Except for RDX, spike recoveries in seawater were satisfactory (89-147%) when samples were fortified at 2 microg/L of each analyte. Spike recoveries from dry sediment fortified at 10 microg/kg of each analyte gave lower recoveries but these could also be due to degradation in the matrix. With a smaller volume of aqueous sample required compared to solid-phase extraction (SPE), SPME is an attractive method for the analysis of limited volumes of sediment pore-water. Moreover, the use of SPME eliminated interferences present in sediment extracts thus allowing the detection of the target analytes that were otherwise difficult to detect by direct injection.

Acetonitriles↗
PubMed1989

Drinking water microbiology--new directions toward water quality enhancement.

Drinking water microbiology has emerged from decades of relative complacency to recognize there can be major concerns with potable water quality. Many of these issues are a result of an explosion of information on new waterborne agents, treatment problems with raw-source water qualities, biofilm development in some distribution systems and specialized requirements in water quality unique to hospitals and industries. Protozoan cyst survival after some disinfection practices involving surface water impoundments and virus occurrence in poorly protected groundwaters have provided reasons for expanding minimum treatment of surface waters and for requiring disinfection of all groundwaters unless there is a demonstrative data base to support exceptions in treatment requirements. Official monitoring of small water supplies must be increased on a monthly basis and a rapid alert established to inform water plant operators of unsatisfactory water qualities. As an option, application of operational tests to analyse water quality in terms of chlorine residual, turbidity, total coliforms and heterotrophic bacterial counts in small water plant operations should be encouraged. This would provide the operator at remote locations with the opportunity to utilize the information to make necessary treatment adjustments or corrections in water distribution deficiencies promptly and be a supplement to the official regional monitoring program. Application of drinking water alternative sources (bottled water and water from point-of-use treatment devices) should be viewed by the health authorities as only a temporary solution, not as a permanent fix for a public water supply known to present some established health risk to consumers. The public must also recognize that bottled water is not frequently monitored by health laboratories for acceptable quality and the use of home treatment devices places the responsibility of proper maintenance on the user. Microbial quality improvements in drinking water to hospitals and food industries can frequently be achieved through a routine, systematic flushing program for building plumbing networks and associated attachment devices. In other situations, use of booster disinfection or point-of-use devices may provide the important special water quality requirements for certain industrial applications. In any event, these supplemental treatment measures will require careful in-plant monitoring and maintenance to prevent reversals in water quality enhancement.

Animals↗
PubMed1992

Nephropathy associated with infection by human immunodeficiency virus: a report on 11 cases including 6 treated with zidovudine.

The human immunodeficiency virus (HIV) was recently suggested to be involved in generating kidney lesions in HIV-associated nephropathy (HIVN). The possibility that antiretroviral agents can slow down the usually explosive evolution of HIVN to end-stage renal failure (ESRF) has not been studied in many of the series of cases published. The present work is a retrospective analysis of 11 patients with histologically proven HIVN, 6 of whom were treated with zidovudine. Seven patients (group 1) either required dialysis at the outset, when HIVN was diagnosed, or progressed very fast to ESRF within 15-45 days. Two patients of this group were treated with zidovudine, but it had no effect on kidney function. In the remaining 4 patients (group 2), HIVN progressed more slowly than in group 1. All 4 patients were treated with zidovudine at an earlier stage of the disease than ESRF. Only 1 deteriorated to ESRF in 9 months. The 3 others, who did not have ESRF, were followed up for 13, 10 and 32 months, respectively. Although this is a preliminary study, its results do suggest that zidovudine can slow down the evolution of HIVN to ESRF. They highlight the need to screen HIV-positive patients regularly for proteinuria, in order to detect HIVN by renal biopsies at an early stage of renal lesion formation.

AIDS-Associated Nephropathy↗
PubMedDate not supplied

Vascular injuries: experience during the Afghanistan War.

This is a prospective study done over an 18-month period in three base evacuation hospitals serving the Afghan refugees in Pakistan. Out of 224 patients, 78 had major and 146 had minor arterial injuries. Late presentation was a common finding. Mine explosions ranked first as a causative agent. This explains the high incidence of lower limb affections and minor vascular injuries. In the major arterial injury group, the superficial femoral artery was the commonest injured (33.4%), followed by the brachial (28.2%). Associated major venous injury occurred in 41% of cases while 25.6% had a compound fracture of the nearby bone. All subclavian and axillary artery injury patients had concomitant brachial plexus injury. Arterial repair was done in 73 patients (93.6%) and ligation in 5. The importance of venous repair was emphasised; venous ligation was done in 6 patients only (19.4%). Repeated extensive debridement was done in 4 patients and useful limbs were left. This is believed to be a good alternative for selected cases with extensive muscle laceration. 3 patients died in the early post-operative period and 3 needed amputation (4%). Other complications were graft sloughing (1.3%) thrombosis (6%) and stenosis (9%). Only 56.9% of patients were followed up for 3-6 months.

Adolescent↗
PubMedDate not supplied

[Cluster cases of malignant pleural mesothelioma in an oil factory].

BACKGROUND: The traditional occupational hazards of the productive cycle of oils are attributable to chemicals (use of solvents, pesticides and other agents), dusts, labour accidents (trauma, ignition, explosion), noise, manual lifting, work organization and hot-wet microclimate. The latest risk is due to the use of high temperatures (from 50 up to 250 degrees C) during the processes of extraction with solvent and refining. No cases are reported in literature of asbestos related disease in subjects who worked in oil factories. Nevertheless the structure and organization of the workplace, which is similar to that of sugar refineries, where cases of malignant mesothelioma have been described (moreover in workers employed in running and maintenance of the plants), led to the assumption that even in oil factories asbestos for the insulation of pipes and boilers could be present. OBJECTIVES: To describe 3 cases of Malignant Mesothelioma that occurred in workers of the same oil factory. METHODS: Since this occupational sector is not conventionally known for asbestos exposure the Local Health Unit and the Lombardy Mesothelioma Registry decided to investigate this industrial plant. RESULTS: Following examination of the archives of the Local Health Unit and inspection of the plant, an environmental asbestos contamination (pipes and boilers) was found. The 3 cases were defined as occupational disease and the required legal procedures were initiated. This underlines the importance of close cooperation with Local Health Units of occupational medicine and the Regional Mesothelioma Registry in the study and acknowledgment of cases which would otherwise not have been recognized, with consequent loss of precious information.

Aged↗
PubMed1994

A brief historical review of non-anaesthetic causes of fires and explosions in the operating room.

Fires and explosions have occurred in the operating theatre for many years. Flammable inhalation anaesthetic agents were responsible for many incidents in the past, but these are no longer available in many countries. Other causes of fires and explosions still exist in the operating theatre and, from time to time, result in serious and occasionally fatal injury. Flammable gastrointestinal gases have been the cause of injury to patients during gastric surgery, laparoscopy and during examination of the large bowel with electrical instrumentation. Gases formed in the bladder during urological procedures have ignited, causing rupture. Alcohol-based skin cleaning agents have resulted in severe burns to the skin. Equipment used for storage and delivery of oxygen to patients has caused fires in a variety of ways. Adhesive skin drapes have resulted recently in two tragic deaths. The increasing use of laser therapy, particularly in ear, nose and throat surgery, and in oral surgery, has brought about a renewed awareness of the risk of fire. The relevant factors which should be borne in mind and the precautions which should be adopted when laser therapy is to be used in the airway are discussed.

Catheterization↗
PubMed1985

[Mental health and the exposure to organic solvents in the workplace.].

Organic solvents, due to their chemical properties have a particular affinity with the nervous system, giving them the power to interfere with the functioning of an element. Case histories and epidemiological studies have shown a relationship between a long term exposure to certain solvents and the danger of neuropathies, encephalopathies and psychiatric troubles. This article's aim is to expose the problem of the deterioration of the well being of persons exposed to neurotoxic agents. A study was made in an explosives factory with workers who were exposed to ethylic ether or ethanol and a control of 74 workers who were not exposed. This is an exploratory study which mostly looks into the prevalence of symptoms that could result from a professional contact with theses neurotoxic agents. The results show that the exposed workers, compared to those who were not exposed, are afflicted with more prenarcotic symptoms at work : such as feelings of drunkeness and difficulties in articulating words. The workers also show more frequently general symptoms such as changes of mood, problems of fatigue, sleep, memory and concentration. The reported numbers of prenarcotic symptoms increase with the degree of exposure. The significance of these results on the mental health of the persons involved is studied.

English Abstract↗
PubMed2003

Recognition of illness associated with exposure to chemical agents--United States, 2003.

Since September 11, 2001, concern has increased about potential terrorist attacks involving the use of chemical agents. In addition, recent cases involving intentional or inadvertent contamination of food with chemicals have highlighted the need for health-care providers and public health officials to be alert for patients in their communities who have signs and symptoms consistent with chemical exposures. For example, in February 2003, a Michigan supermarket worker was charged with intentionally contaminating 200 lbs. of meat with a nicotine-containing insecticide. Although intentional release of chemical agents might be an overt event (i.e., one whose nature reveals itself), such as release of a nerve agent in a subway or a large explosion of a chemical container, a chemical release might instead be a covert event (i.e., an unrecognized release in which the presence of ill persons might be the first sign of an exposure), such as deliberate contamination of food, water, or a consumer product. To increase the likelihood that health-care providers will recognize a chemical-release-related illness and that public health authorities will implement the appropriate emergency response and public health actions, CDC identified examples of chemical-induced illness and created appropriate guidance for health-care providers and public health personnel. This report summarizes the epidemiologic clues and clinical signs or patterns of illness that might suggest covert release of a chemical agent. CDC is working to develop national surveillance capabilities for detecting chemical-release-related illnesses.

Chemical Warfare Agents↗
PubMed2000

Separation and detection of explosives on a microchip using micellar electrokinetic chromatography and indirect laser-induced fluorescence

A new approach for sensitive detection on a microfabricated chip is presented. Indirect laser-induced-fluorescence (IDLIF) was used to detect explosive compounds after separation by micellar electrokinetic chromatography (MEKC). The detection setup was used in an epifluorescence configuration with excitation provided by a near-IR diode laser operating at 750 nm. To achieve indirect detection, a low concentration of a dye (5 microM Cy7) was added to the running buffer as a visualizing agent. Using this methodology, a sample containing 14 explosives (EPA 8330 mixture) was examined. Concentrations of 1 ppm of trinitrobenzene (TNB), trinitrotoluene (TNT), dinitrobenzene (DNB), tetryl, and 2,4-dinitrotoluene (2,4-DNT) could be detected with S/N ratios between 3 and 10. Analyses showing 10 peaks, with plate numbers on the order of 60000, were completed within 60 s using a 65 mm long separation channel. The three isomers of nitrotoluene (2-, 3-, and 4-nitrotoluene) were not resolved. Additionally, the two nitramines (HMX and RDX) could only be detected at much higher concentrations, likely due to the low fluorescence quenching efficiencies of these compounds. The analysis method was also used to separate and detect nitroaromatic compounds in extracts from spiked soil samples. The presence of 1 ppm (1 microg of analyte/1 g of soil) of TNB, DNB, TNT, tetryl, 2,4-DNT, 2,6-DNT, 2-NH2-4,6-DNT, and 4-NH2-2,6-DNT could readily be detected. In the interest of increasing the sensitivity of the analysis, various on-chip injection schemes were evaluated. It was found that a 250 microm double-T injector gave a 35% increase in peak signal compared to a straight-cross injector, which is less than expected based on injected volume.

Journal Article↗
PubMed1992

A comparison of the chemical repair rates of free radical precursors of DNA damage and cell killing in Chinese hamster V79 cells.

One of the important temporal stages of radiation action in cellular systems is the chemical phase, where oxygen fixation reactions compete with chemical repair reactions involving reducing agents such as GSH. Using the gas explosion technique it is possible to follow the kinetics of these fast (greater than 1 ms) reactions in intact cells. We have compared the chemical repair kinetics of the oxygen-dependent free radical precursors leading to DNA single-strand and double-strand breaks, measured using filter elution techniques, with those leading to cell killing in V79 cells. The chemical repair rates for DNA dsb (670s-1 at pH 7.2 and 380s-1 at pH 9.6) and cell killing (530s-1) were similar. This is in agreement with the important role of DNA dsb in radiation induced cell lethality. The rate for DNA ssb precursors was significantly slower (210s-1). The difference in rate between DNA ssb and dsb precursors may be explained on the basis of a dsb free radical precursor consisting of a paired radical, one radical on each strand. The instantaneous probability of one or other of these radicals being chemically repaired and not proceeding to form a dsb will be twice that of ssb radical precursor. This agrees well with the concept of locally multiply damaged sites (LMDS) produced from clusters of ionizations in DNA (Ward 1985).

Animals↗