Publications by authors named "Shoetsu Chiba"

Drug membrane transport system proteins, namely, drug transporters, are expressed in the kidney and liver and play a crucial role in the excretion process. This study aimed to elucidate the interactions of the drug transporters human organic anion transporters 1, 2, 3, 4 (hOAT1, 2, 3, 4) and human organic cation transporters 1, 2, 3 (hOCT1, 2, 3), which are expressed primarily in human kidney, liver, and brain, with the stimulants methamphetamine (METH) and amphetamine (AMP). The results of an inhibition study using representative substrates of hOATs and hOCTs showed that METH and AMP significantly inhibited (by >50%) uptake of the hOCT1 and hOCT3 representative substrate 1-methy1-4-phenylpyridinium ion (MPP) and hOCT2 representative substrate tetraethyl ammonium (TEA).

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We report an autopsy-proven case of a 33-year-old man who died of intimal sarcoma of the pulmonary artery. A large mass (5×4 cm) occluded the main and bilateral pulmonary arteries. Tumor cell morphology was consistent with that of undifferentiated pleomorphic sarcoma.

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Syphilis, a sexually transmitted infection caused by the bacterium Treponema palladium, is experiencing a worldwide resurgence. The risk of syphilis infection is particularly high in men who have sex with men (MSM), especially those who are human immunodeficiency virus (HIV)-positive. Untreated syphilis can lead to rare but severe late-stage complications, including syphilitic aortitis.

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We present the first report of pneumopericardium observed by autopsy and on postmortem computed tomography (PMCT) images. The subject was a woman who died of self-inflicted stab wounds to the abdomen. The PMCT scan revealed air in the pericardial sac, a "flattened heart" sign, and retroperitoneal hemorrhage.

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Article Synopsis
  • Fat embolism syndrome (FES) is a serious but rare complication associated with long bone fractures, characterized by inflammation and potential organ damage.
  • The study used rats to investigate how neutral fat and fatty acids affect lung-to-body weight ratios, histological changes, and inflammatory cytokine levels in various organs.
  • Findings revealed that neutral fat formed emboli in lung capillaries, increasing inflammatory cytokines like IL-1β, IL-6, and TNF-α, while oleic acid elevated cytokine levels without forming emboli, indicating different mechanisms of inflammation.
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  • * The study investigates the role of Rho-kinases (ROCK1 and ROCK2) in the release of the inflammatory marker IL-1β from human monocytic THP-1 cells when exposed to multi-walled carbon nanotubes (MWCNT) and asbestos.
  • * Results showed that blocking ROCKs with a specific inhibitor reduced IL-1β secretion caused by MWCNTs and asbestos but not by lipopolysaccharide (LPS), suggesting ROCKs play a crucial role in the inflammatory response triggered by fibrous particles.
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  • Human organic cation transporter 2 (hOCT2) is located in the kidney and helps transport various compounds, including drugs and toxins, into proximal tubular cells.
  • Researchers tested multiple drug classes (like analgesics and anti-depressants) using specially cultured cells to see if they could inhibit the transport of a common OCT2 substrate (14C-TEA).
  • Several compounds significantly inhibited this uptake, indicating that different drugs can affect how well the kidneys clear substances transported by hOCT2, suggesting the need for more studies on its impact on drug metabolism.
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Hydrogen sulfide (H₂S) is a toxic gaseous substance, and accidental exposure to high concentrations of H₂S has been reported to be lethal to humans. Inhaled and absorbed H₂S is partially dissolved within the circulation and causes toxic effects on lymphocytes. However, the mechanisms involved in H₂S toxicity have not been well documented.

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Renal excretion is an important elimination pathway for substances associated with forensic toxicology, such as medicines, agricultural chemicals, and industrial chemicals. This study aimed to elucidate the renal elimination pathway of substances using culture cells stably expressing the human organic anion transporter 1 (hOAT1) gene. Substances tested were diazepam, triazolam, haloperidol, amitriptyline, mianserin, bromovalerylurea, phenobarbital, acetaminophen, acetylsalicylic acid, lidocaine, aconitine, atropine, caffeine, nicotine, malathion, dichlorvos, fenitrothion, chlorpyrifosmethyl, paraquat, diquat, potassium cyanide, sodium arsenite, sodium azide, o-cresol, and probenecid (control, a representative inhibitor of hOAT1).

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