Accelerated silicosis in sandblasters: Pathology, mineralogy, and clinical correlates.

BACKGROUND: With increasing reports of accelerated and acute silicosis, PMF, and autoimmune disease among coal miners and silica-exposed countertop workers, we present previously incompletely-described pulmonary pathology of accelerated silicosis and correlations with mineralogy, radiography, and disease progression in 46 Texas oilfield pipe sandblasters who were biopsied between 1988 and 1995. METHODS: Worker examinations included pulmonary function tests, chest X-ray (CXR), high-resolution computed tomography (HRCT), and Gallium-67 scans. Quantitative mineralogic analysis of pulmonary parenchymal burden of silica, silicates, and metal particles used scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM EDS). RESULTS: Workers had clinical deterioration after <10 years exposure in dusty workplaces. Although initial CXR was normal in 54%, Gallium-67 scans were positive in 68% of those with normal CXR, indicating pulmonary inflammation. The histology of accelerated silicosis is diffuse interstitial infiltration of macrophages filled with weakly birefringent particles with or without silicotic nodules or alveolar proteinosis. Lung silica concentrations were among the highest in our database, showing a dose-response relationship with CXR, HRCT, and pathologic changes (macrophages, fibrosis, and silicotic nodules). Radiographic scores and diffusing capacity worsened during observation. Silica exposure was intensified, patients presented younger, with shorter exposure, more severe clinical abnormalities, higher lung particle burdens, and more rapid progression in a subset of patients exposed to recycled blasting sand. CONCLUSIONS: Accelerated silicosis may present with a normal CXR despite significant histopathology. Multivariable analyses showed silica, and not other particles, is the driver of observed radiologic, physiologic, and histologic outcomes. Eliminating this preventable disease requires higher physician, public health, and societal awareness.

Examination of firearm gunpowders by scanning electron microscopy/energy dispersive X-ray analysis.

The surfaces of thirty-one gunpowders (GPs) from Winchester, Federal, Hercules, DuPont, and Remington were examined by scanning electron microscopy/energy dispersive X-ray spectroscopy. Particles and surface coatings on 22 of the GPs had compositions of sulfur/potassium/barium or sulfur/potassium detected. Primer-like particles composed of lead/antimony/barium were found on surfaces of twelve GPs. Gunpowders from fifteen different lots of Winchester 9 mm Silvertip® hollow point cartridges were found to vary in GP type (flake and flattened ball) and associated inorganic compounds of sulfur/potassium/barium or sulfur/potassium or one with only potassium. No inorganic particles or coatings were detected on two of these Winchester GPs. The elements from the inorganic compounds on GPs likely contribute to gunshot residue generated by the discharge of a firearm.

A case of alleged discharge of a firearm within a vehicle.

A road-rage altercation occurred between two vehicle drivers. The driver of vehicle 1 stopped and allegedly fired two shots from within his vehicle over the heads of the driver and passenger of vehicle 2 when they were out of their vehicle. The driver of vehicle 2, an off-duty police officer, fired his .45 calibre pistol at the driver of vehicle 1. The bullet went through the windshield and lodged in the instrument panel. Eight gunshot residue (GSR) samples were taken from the interior of vehicle 1 and analysed by automated scanning electron microscopy/energy dispersive x-ray spectroscopy. The results show for vehicle 1 that a firearm discharged with its breach or cylinder gap within the vehicle was unlikely to have occurred and the .45 calibre bullet which impacted five surfaces of vehicle 1 was accompanied by GSR throughout its travel. A recreational shooter is shown in this study to transfer GSR to the seat of his car. The driver of vehicle 1 visited a recreational gun range prior to the altercation, which would explain the significant GSR contamination of the driver's seat of his vehicle.

Discharge of a Pistol Out a Car Window with the Breech Within the Interior of the Car: Analysis of Gunshot Residue on a Car's Interior Surfaces.

The defendant, the driver of the questioned car, allegedly extended his right arm over the passenger seat and fired a single shot from a 380 pistol out the passenger window with the pistol's breech within the car. A simulation of this shooting scenario using the same model car, but different year, was conducted to quantitate gunshot residue (GSR) contamination of interior surfaces within the car. The test car's dash and headliner/window frame above the pistol had the heaviest GSR contamination. The dash GSR from airborne deposition documents a firearm discharge within the vehicle. Transfer from GSR-contaminated hands or clothing to the dash is unlikely. The heavy GSR contamination of the headliner/window frame above the pistol likely documents the window from which the pistol was fired, but additional experiments are needed to verify.

The Effect of Skin Debris on Gunshot Residue Sampling and Detection.

These experiments were designed to determine whether skin debris (desquamated epithelial cells and apparent skin oils) affects gunshot residue (GSR) particle detection on the sticky tape lift samples prepared for scanning electron microscopy (SEM). A dabbing experiment showed that GSR particles accumulate not only on the adhesive surface of the sampler, but also on the epithelial cell surfaces. Samplers were loaded with target GSR followed by dabbing 30 times on the back of a hand. Backscatter electron images were taken at 20 kV and for some at 30 kV of the same areas. The samplers were then treated with a sodium/calcium hypochlorite solution (bleach) to remove skin debris and again imaged in the SEM. Comparison of these images shows more GSR particles will likely be revealed at 30 kV than 20 kV and more particles revealed by the bleach treatment in an automated SEM system.

Pathologic spectrum and lung dust burden in giant cell interstitial pneumonia (hard metal disease/cobalt pneumonitis): review of 100 cases.

Hard metal disease (HMD), the interstitial lung disease caused by dusts in the cemented tungsten carbide (WC) industry, has been attributed to cobalt. The rare histologic pattern of giant cell interstitial pneumonia (GIP) is characteristic in HMD. The authors reviewed the history of HMD and 100 cases of HMD that they have seen over 5 decades. GIP was proven in 59; analysis of the lung inorganic particle burden by scanning electron microscopy and energy-dispersive x-ray spectroscopy confirmed HMD in the other 41. Cases have been diagnosed by bronchoalveolar lavage, lung biopsy, and autopsy. Histopathology findings range from focal peribronchiolar inflammation to diffuse interstitial fibrosis and honeycombing. GIP cases in the WC industry reveal elevated concentrations of tungsten in all, but cobalt was detected in only 6 ( approximately 10%). Of the 746 diverse cases in the authors' analytical database, almost all cases with the highest tungsten concentration showed GIP. This study confirms that GIP is effectively pathognomonic for HMD.

Aspects of the circulatory system of Pollicipes polymerus J. B. Sowerby (Cirripedia: Thoracica).

The circulatory system of Pollicipes polymerus exhibits a high degree of organization which precludes it from being referred to as an open system. The system is arbitrarily divided into four parts: (1) the circulation of the peduncle and mantle; (2) the distributive circulation of the body, which provides hemolymph to most of the cephalic gut, to the maxillary gland, and to the cirri; (3) the peripheral circulation which distributes blood from the cirri to the peripheral areas of the thoracic region, to most of the thoracic gut, and from the scutal sinus to the peripheral areas of the cephalic region; and (4) the collecting circulation, which conveys hemolymph mostly from the peripheral circulation of the body to the peduncle. There also may be a circulation that is comparable to the vertebrate lymphatic system. Pumping of hemolymph can be attributed to three pairs of skeletal muscles that compress the dorsolateral channels. These muscles are unique for crustacean muscles in that they do not appear to be striated. The rostral vessel appears to be a vestige of a heart in which the pump muscles have been lost. There is a similarity of the rostral vessel to the heart of Calanus finmarchicus (a copepod). This is additional evidence linking the cirripeds with the copepods within the Maxillopoda. Electron microscope observations of the walls of the midsagittal vessels indicate that there is a more or less random layering of cellular and noncellular elements within the wall. Muscle cells appear to be incorporated in the vessel wall.

Blood circulation in the balanomorph barnacle, Megabalanus californicus (Pilsbry).

Compared to the lepadomorph barnacles, the morphology of hemolymph circulation in the balanomorphs is poorly known. This report on Megabalanus californicus is the first detailed description of blood circulation in a balanomorph barnacle. In Megabalanus hemolymph circulates in a similar pattern to that seen in lepadomorphs. However, Megabalanus shows major differences. (1) The mantle and associated structures ( =peduncle in the lepadomorphs) shows no large sinuses and blood is directed to branchiae via well defined vessels. (2) The gut is entirely invested with vessels from the distributive system (except for the proctodaeum). (3) A large sinus in the thoracic region (thoracic sinus) has no similar structure in the lepadomorphs. (4) The prosomal sinus is reduced and positioned dorsally. (5) The rostral sinus is larger than any found in the lepadomorphs and receives a substantial amount of blood from the peripheral circulation. The smallness of the prosomal sinus in Megabalanus probably is due to lack of a contractile peduncle. In the lepadomorphs the prosomal sinus likely serves as a storage sinus for hemolymph when the peduncle is contracted.

Fatal asbestosis 50 years after brief high intensity exposure in a vermiculite expansion plant.

The authors report the case of a 65-year-old accountant whose only asbestos exposure was during a summer job 50 years earlier in a California vermiculite expansion plant. Vermiculite is a silicate material that is useful in building and agriculture as a filler and insulating agent. He developed extensive fibrocalcific pleural plaques and end-stage pulmonary fibrosis, with rapidly progressive respiratory failure. Careful occupational and environmental history revealed no other source of asbestos exposure, and the initial clinical diagnosis was idiopathic pulmonary fibrosis; open lung biopsy shortly before his death confirmed asbestosis. Electron microscopic lung fiber burden analysis revealed over 8,000,000 asbestos fibers per gram dry lung, 68% of which were tremolite asbestos. Additional asbestiform fibers of composition not matching any of the standard asbestos varieties were also present at over 5,000,000 fibers per gram dry lung. Comparison analysis of a sample of Libby, Montana, vermiculite showed a similar mix of asbestiform fibers including tremolite asbestos. This case analysis raises several concerns: risks of vermiculite induced disease among former workers of the more than 200 expansion plants throughout the United States; health effects of brief but very high-intensity exposures to asbestos; and possible health effects in end-users of consumer products containing vermiculite.