[Challenges and solutions for laboratory operation and maintenance].

There are several kinds of medical laboratory accreditation scheme in Japan, such as ISO 15189, CAP, and JCI. The purpose of receiving a laboratory accreditation is not merely to receive the accreditation. It ensures Quality Management System (QMS) with technical competence as assessed by a third party. The most important point to establish and maintain QMS is not that it is driven by the accreditation scheme requirements, but that it advances them. The laboratory shall understand the philosophy of each requirement. These requirements are not cutting-edge; they are just ordinary for laboratory work. ISO 15189 was revised in 2012. Depending on this revision, ISO 15189 requirements may become more user-friendly. This is a chance to review and make up for the lack of QMS, and for the improvement of laboratory practices.

Modulation of P2X receptors in dorsal root ganglion neurons of streptozotocin-induced diabetic neuropathy.

Painful diabetic neuropathy causes hyperalgesia and does not respond to commonly used analgesics such as non-steroidal anti-inflammatory drugs or opioids at doses below those producing disruptive side effects. In the present study, we examined the effect of P2X receptor antagonists, which are known to modulate the pain pathway, on mechanical hyperalgesia in streptozotocin (STZ)-induced diabetic mice. The paw withdrawal frequency measured by von Frey filaments, began to significantly increase 5 days after STZ injection and was maintained for more than 14 days. Intrathecal administration of P2X receptor antagonists (PPADS and TNP-ATP) inhibited the mechanical allodynia in diabetic mice. The levels of P2X(2) and P2X(3) receptors mRNA were significantly increased in diabetic mice at 14 days after the intravenous injection of STZ. These results suggest that the upregulation of P2X(2), P2X(3) and/or P2X(2/3) receptor in DRG neurons is associated with mechanical allodynia in STZ-induced diabetic mice.

Contribution of Ca(2+) -dependent protein kinase C in the spinal cord to the development of mechanical allodynia in diabetic mice.

In this paper, we directly demonstrate, for the first time, the activation of Ca(2+)-dependent protein kinase C (PKC) in the spinal cord of diabetic mice. In streptozotocin (STZ)-treated (200 mg/kg, i.v.) diabetic mice, hypersensitivity (allodynia) to mechanical stimulation appeared 7 d after STZ injection. This mechanical allodynia was inhibited by intrathecal injection of the PKC inhibitors 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7) and calphostin C, but not the protein kinase A inhibitor N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide (H-89). The activity of membrane-associated Ca(2+)-dependent PKC in the spinal cords of STZ-induced diabetic mice was significantly higher than that observed in non-diabetic mice. These results suggest that activation of Ca(2+)-dependent PKC in the spinal cord, contributes to the mechanical allodynia in the pain associated with diabetic neuropathy.

Intrathecal alpha2 adrenoceptor agonist clonidine inhibits mechanical transmission in mouse spinal cord via activation of muscarinic M1 receptors.

We examined the role of the spinal muscarinic receptor subtype in the anti-nociceptive effect of intrathecal (i.t.) alpha2 adrenoceptor agonist clonidine in mice. I.t. injection of the muscarinic receptor antagonist atropine completely inhibited i.t. clonidine-induced increase in the mechanical threshold, but did not affect the increase in tail-flick latency induced by i.t. clonidine. The clonidine-induced increase in mechanical threshold was inhibited by i.t. injection of the M1 receptor antagonist pirenzepine in a dose-dependent manner, and by the M3 receptor antagonist 4-DAMP, but not by the M2 receptor antagonist methoctramine. The potency of pirenzepine was greater than that of 4-DAMP. These results suggest that the clonidine-induced increase in mechanical threshold is mediated via the activation of M1 receptors in the spinal cord.