[One case report of pneumoconiosis in porcelain teeth workers].

Porcelain tooth technology is widely used in the treatment of oral diseases, but there are few reports on the possible occupational hazard factors in the process of porcelain tooth production. Porcelain teeth production will produced a large amount of silica dust and metal dust during the grinding process. The technical workers who have been engaged in this work for a long time are very prone to pneumoconiosis due to their poor personal protection awareness. This paper analyzed the clinical data of a pneumoconiosis patient engaged in porcelain tooth making, and analyzed the possible occupational hazard factors in the process of porcelain teeth production, so as to improve the understanding of relevant enterprises, technical workers and medical personnel on the disease and reduce the risk of porcelain teeth production workers suffering from pneumoconiosis.

Myositis due to the microsporidian Anncaliia (Brachiola) algerae in a lung transplant recipient.

Microsporidia are obligate intracellular parasites, more closely related to fungi than protozoa on molecular phylogenetic analysis, and are known to be a rare cause of opportunistic infection in immune compromised patients including human immunodeficiency virus-positive patients and solid organ transplant recipients. We report the first case to our knowledge of microsporidial myositis in a lung transplant recipient. He was 49 years old and had received a lung transplant in 2000 for cystic fibrosis. He presented in 2009 with fevers, chronic diarrhea, myalgia, and pancytopenia, and developed progressive weakness and neurological symptoms before his death 35 days after hospital admission. Multiple investigations, including stool culture, rectal biopsy, colonoscopy, cerebrospinal fluid examination, bone marrow biopsy, lung biopsy, and bronchoalveolar lavage, failed to reveal a definite cause for the patient's deterioration. The diagnosis of microsporidial infection was made on post-mortem light microscopic examination of tissue sections of the tongue and deltoid muscle. Light microscopy diagnosed a microsporidial myositis, confirmed by transmission electron microscopy, which suggested that the organism was Brachiola species. The identity of the organism was confirmed by polymerase chain reaction as Brachiola algerae (recently renamed Anncaliia algerae). The case highlights the need to consider protozoal organisms in the differential diagnosis of myalgia and multisystemic infections in immune compromised patients.

In vivo tissue reaction within the outflow conduit in patients supported by HeartWare HVAD.

AIM: The frequency, extent, and nature of tissue ingrowth within the continuous-flow left ventricular assist device (cf-LVAD) outflow conduit has not been systematically assessed. We sought to characterize conduit histopathology at explantation in a cohort of patients with HeartWare ventricular assist device (HVAD) and assess the effect on pump performance. METHODS: Patients undergoing routine histopathological assessment of a HeartWare HVAD removed at transplantation or autopsy were assessed. Outflow conduits were examined macroscopically, and visible tissue was sectioned for microscopic evaluation. In patients who had undergone prior contrast-enhanced computerized tomography (CT) with HVAD in situ, the outflow conduit was measured at the aortic anastomosis and 5 cm proximal to the anastomosis, in the axial and sagittal planes. All patients had their pump flow, flow pulsatility, current, and speed determined from log files examined at 1, 3, 6, 9, and 12 months after LVAD implantation. RESULTS: Twenty-five consecutive patients were assessed (24 LVAD, 1 biventricular assist device (BiVAD)). Of the 26 outflow grafts assessed, there was evidence of tissue ingrowth reaction in 24 (92%) grafts. The most common site was the distal anastomosis (18/24, 75%), with the graft body involved in 14 of 24 (58%) grafts. Microscopic evaluation revealed acute inflammatory infiltrate in 4 of 24 grafts (17%), chronic inflammatory infiltrate in 14 of 24 (58%), neointima formation in 18 of 24 (75%) and fibrosis in 18 of 24 (75%) grafts. The median depth of tissue was 1 mm (range, 0-2 mm). The mean conduit diameter was 9.5 ± 0.6 mm at the aortic anastomosis compared with 11.1 ± 0.5 mm 5 cm proximal to the anastomosis (p < 0.0001). In patients with unchanged pump speed one month after implantation, analysis of log files revealed a significant (5.8 ± 8.6%) decrease in pump flow (4.65 ± 0.86 vs 4.38 ± 0.92 L/min, p = 0.01) and flow pulsatility (5.00 ± 1.10 vs 4.16 ± 1.05 L/min, p = 0.006). CONCLUSIONS: There is evidence of tissue formation within the HVAD outflow conduit in the vast majority of patients, most commonly located at the aortic anastomosis. This is associated with significantly decreased pump flow over time.

Inhibition of the human ether-a-go-go-related gene (HERG) potassium channel by cisapride: affinity for open and inactivated states.

1 Cisapride is a prokinetic agent which has been associated with QT prolongation, torsades de pointes and cardiac arrest. The cellular mechanism for these observations is high affinity blockade of IKr (encoded by HERG). 2 In a chronic transfection model using CHO-K1 cells, cisapride inhibited HERG tail currents after a step to +25 mV with similar potency at room and physiological temperatures (IC50 16. 4 nM at 20-22 degrees C and 23.6 nM at 37 degrees C). 3 Channel inhibition exhibited time-, voltage- and frequency-dependence. In an envelope of tails test, channel blockade increased from 27+/-8% after a 120 ms depolarizing step to 50+/-4% after a 1.0 s step. These findings suggested affinity for open and/or inactivated channel states. 4 Inactivation was significantly accelerated by cisapride in a concentration-dependent manner and there was a small (-7 mV) shift in the voltage dependence of steady state inactivation. 5 Channel blockade by cisapride was modulated by [K+]o, with a 26% reduction in the potency of channel blockade when [K+]o was increased from 1 to 10 mM. 6 In conclusion, HERG channel inhibition by cisapride exhibits features consistent with open and inactivated state binding and is sensitive to external potassium concentration. These features may have significant clinical implications with regard to the mechanism and treatment of cisapride-induced proarrhythmia.

Inhibition of HERG channels stably expressed in a mammalian cell line by the antianginal agent perhexiline maleate.

Perhexiline has been used as an anti-anginal agent for over 25 years, and is known to cause QT prolongation and torsades de pointes. We hypothesized that the cellular basis for these effects was blockade of I(Kr). A stable transfection of HERG into a CHO-K1 cell line produced a delayed rectifier, potassium channel with similar properties to those reported for transient expression in Xenopus oocytes. Perhexiline caused voltage- and frequency-dependent block of HERG (IC50 7.8 microM). The rate of inactivation was increased and there was a 10 mV hyperpolarizing shift in the voltage-dependence of steady-state inactivation, suggestive of binding to the inactivated state. In conclusion, perhexiline potently inhibits transfected HERG channels and this is the probable mechanism for QT prolongation and torsades de pointes. Channel blockade shows greatest affinity for the inactivated state.

Blockade by N-3 polyunsaturated fatty acid of the Kv4.3 current stably expressed in Chinese hamster ovary cells.

1. The Kv4.3 gene is believed to encode a large proportion of the transient outward current (Ito), responsible for the early phase of repolarization of the human cardiac action potential. There is evidence that this current is involved in the dispersion of refractoriness which develops during myocardial ischaemia and which predisposes to the development of potentially fatal ventricular tachyarrhythmias. 2. Epidemiological, clinical, animal, and cellular studies indicate that these arrhythmias may be ameliorated in myocardial ischaemia by n-3 polyunsaturated fatty acids (n-3 PUFA) present in fish oils. 3. We describe stable transfection of the Kv4.3 gene into a mammalian cell line (Chinese hamster ovary cells), and using patch clamp techniques have shown that the resulting current closely resembles human Ito. 4. The current is rapidly activating and inactivating, with both processes being well fit by double exponential functions (time constants of 3.8 +/- 0.2 and 5.3 +/- 0.4 ms for activation and 20.0 +/- 1.2 and 96.6+/-6.7 ms for inactivation at +45 mV at 23 degrees C). Activation and steady state inactivation both show voltage dependence (V1/2 of activation= -6.7+/-2.5 mV, V1,2 of steady state inactivation= -51.3+/-0.2 mV at 23 degrees C). Current inactivation and recovery from inactivation are faster at physiologic temperature (37 degrees C) compared to room temperature (23 degrees C). 5. The n-3 PUFA docosahexaenoic acid blocks the Kv4.3 current with an IC50 of 3.6 micromol L(-1). Blockade of the transient outward current may be an important mechanism by which n-3 PUFA provide protection against the development of ventricular fibrillation during myocardial ischaemia.

Comparison of parenteral nutrition supplemented with L-glutamine or glutamine dipeptides.

Although glutamine is an important fuel used by the intestinal mucosa and other visceral organs, it is not present in any commercially available parenteral amino acid solution. To compare the effects of L-glutamine with glutamine dipeptides, we studied the effects of each in 8 dogs and 60 Wistar rats. In the dog study, three amino acid solutions were compared: standard commercial amino acid solution (control), alanine-glutamine dipeptide-enriched solution (glutamine 3.4%), and glycine-glutamine dipeptide-enriched solution (glutamine 3.6%). Arterial and venous samples were collected to compare the effects of the three solutions on skeletal muscle amino acid exchange. In the rat study, two studies were undertaken: group 1 rats underwent only central venous catheterization; group 2 rats underwent central venous catheterization and a 50% intestinal resection. Within each group, three different solutions were infused: standard amino acid solution (control), glutamine-enriched (1.5% glutamine) solution, or glutamine dipeptide-enriched (1% glutamine) solution. After 7 days of parenteral nutrition, samples of gut, blood, and muscle were collected for determination of mucosal thickness, villus area, serum amino acid profile, liver and renal function tests, and muscle composition. When glutamine or glutamine-dipeptide solutions were administered, the dogs showed increasing serum glutamine concentrations and enhanced glutamine uptake across the hind leg muscle. Similarly, both groups of rats demonstrated significant differences in serum glutamine levels, nitrogen balance, intestinal mucosa thickness, and villus area. We conclude that both glutamine and glutamine-dipeptide infusions increase serum glutamine concentrations and result in regional tissue effects. Both exerted similar metabolic effects with no apparent complications.

A potassium ion channel is involved in cytokine production by activated human macrophages.

Macrophages play an important role in immune and inflammatory responses, largely through secretion of bioactive molecule such as cytokines. While calcium is known to be an important regulator of this process, less is known about the role of other ions and the ion channels that regulate them. We have previously implicated an outwardly rectifying potassium channel (Kor) in this process and for this reason we have investigated the role of potassium (K+) and K+ channels in the regulation of tumour necrosis factor-alpha (TNF-alpha)and interleukin (IL)-8 production by activated human culture-derived macrophages. The effect of blockade of Kor is to inhibit phorbol myristate acetate (PMA)-induced cytokine production by translational or post-translational mechanisms, an effect that is duplicated by increasing extracellular K+. By contrast, the effects of K+ on LPS-stimulated cells are far more complex and are probably mediated through the change of osmolality and occur largely at the mRNA level. This data directly implicates K+, and its regulation through Kor, in early events following PMA stimulation of these cells.

The immunomodulatory compound 2-acetyl-4-tetrahydroxybutyl imidazole causes sequestration of lymphocytes in non-lymphoid tissues.

2-Acetyl-4(5)-(1,2,3,4-tetrahydroxybutyl) imidazole (THI) is an immunomodulatory compound which causes a reversible lymphopenia in mice by an unknown mechanism. In this study, we investigated the whereabouts of cells lost from the blood and the spleen during THI treatment Homing studies following is injection of fluorescently labelled splenocytes into THI-pretreated recipients showed that THI increased labelled cells in the liver, lungs and kidneys of THI-treated mice. Furthermore, the sequestration in the liver occurred just 1.5 h after injection of labelled cells with the increase still being present at 24 h after injection. Microscopic examination of liver sections indicated that fluorescent lymphocytes were clustered within the liver sinusoids in THI-treated mice, possibly associated with endothelial cells. The liver retention of lymphocytes was confirmed by immunohistochemical studies which showed a significant increase of T cells in the liver of THI-treated mice. To determine the subset of lymphocytes which are lost from the spleen and sequestered in non-lymphoid organs, lymphocytes remaining in the spleen after THI treatment were characterized. Our results confirmed that THI reduced B cells, CD4+ and CD8+ T cells and cells expressing CD62L, CD44 and IL-2R in the spleen.

The nuclear chloride ion channel NCC27 is involved in regulation of the cell cycle.

NCC27 is a nuclear chloride ion channel, identified in the PMA-activated U937 human monocyte cell line. NCC27 mRNA is expressed in virtually all cells and tissues and the gene encoding NCC27 is also highly conserved. Because of these factors, we have examined the hypothesis that NCC27 is involved in cell cycle regulation. Electrophysiological studies in Chinese hamster ovary (CHO-K1) cells indicated that NCC27 chloride conductance varied according to the stage of the cell cycle, being expressed only on the plasma membrane of cells in G2/M phase. We also demonstrate that Cl- ion channel blockers known to block NCC27 led to arrest of CHO-K1 cells in the G2/M stage of the cell cycle, the same stage at which this ion channel is selectively expressed on the plasma membrane. These data strongly support the hypothesis that NCC27 is involved, in some as yet undetermined manner, in regulation of the cell cycle.

Crystal structure of a soluble form of the intracellular chloride ion channel CLIC1 (NCC27) at 1.4-A resolution.

CLIC1 (NCC27) is a member of the highly conserved class of chloride ion channels that exists in both soluble and integral membrane forms. Purified CLIC1 can integrate into synthetic lipid bilayers forming a chloride channel with similar properties to those observed in vivo. The structure of the soluble form of CLIC1 has been determined at 1.4-A resolution. The protein is monomeric and structurally homologous to the glutathione S-transferase superfamily, and it has a redox-active site resembling glutaredoxin. The structure of the complex of CLIC1 with glutathione shows that glutathione occupies the redox-active site, which is adjacent to an open, elongated slot lined by basic residues. Integration of CLIC1 into the membrane is likely to require a major structural rearrangement, probably of the N-domain (residues 1-90), with the putative transmembrane helix arising from residues in the vicinity of the redox-active site. The structure indicates that CLIC1 is likely to be controlled by redox-dependent processes.