Discrimination of dimethylamphetamine and methamphetamine use: simultaneous determination of dimethylamphetamine-N-oxide and other metabolites in urine by high-performance liquid chromatography-electrospray ionization mass spectrometry

A simple and sensitive method by high-performance liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) has been investigated for the simultaneous determination of dimethylamphetamine (DMA), its specific yet labile main metabolite dimethylamphetamine-N-oxide (DMAO), and other metabolites, methamphetamine (MA) and amphetamine (AP), in urine. A combination of Bond Elut SCX columns for the solid-phase extraction of urine and a semi-micro SCX column for LC separations provided satisfactory results. The use of acetonitrile/5mM ammonium acetate buffer adjusted to pH 4 (65:35, v/v) as the mobile phase at a flow rate of 0.2 mL/min was found to be the most effective. The detection limits were 5 ng/mL for DMAO, 10 ng/mL for DMA and MA, and 50 ng/mL for AP in the SIM mode.     

Cerebral blood flow in infants: comparison of carotid blood flow and cerebral blood velocity

Carotid blood was measured with a ultrasonic volume flow meter in 38 infants. The carotid blood flow was 1.50 +/- 0.55 ml/sec. At the same time peak systolic flow velocity, mean blood velocity, end diastolic velocity, pulsatility index (PI) and resistance index (RI) in the middle and anterior cerebral arteries were measured by duplex Doppler scanning. There was a correlation between the carotid blood flow and the mean blood velocity in middle and anterior cerebral arteries. However, PI and RI were not well correlated with carotid blood flow.     

Anesthetic Effects on Mitochondrial ATP-sensitive K Channel

Background : Volatile anesthetics show an ischemic preconditioning-like cardioprotective effect, whereas intravenous anesthetics have cardioprotective effects for ischemic-reperfusion injury. Although recent evidence suggests that mitochondrial adenosine triphosphate-regulated potassium (mitoKATP) channels are important in cardiac preconditioning, the effect of anesthetics on mitoKATP is unexplored. Therefore, the authors tested the hypothesis that anesthetics act on the mitoKATP channel and mitochondrial flavoprotein oxidation.

Methods : Myocardial cells were isolated from adult guinea pigs. Endogenous mitochondrial flavoprotein fluorescence, an indicator of mitochondrial flavoprotein oxidation, was monitored with fluorescence microscopy while myocytes were exposed individually for 15 min to isoflurane, sevoflurane, propofol, and pentobarbital. The authors further investigated the effect of 5-hydroxydeanoate, a specific mitoKATP channel antagonist, on isoflurane- and sevoflurane-induced flavoprotein oxidation. Additionally, the effects of propofol and pentobarbital on isoflurane-induced flavoprotein oxidation were measured.

Results : Isoflurane and sevoflurane induced dose-dependent increases in flavoprotein oxidation (isoflurane: R2 = 0.71, n = 50; sevoflurane: R2 = 0.86, n = 20). The fluorescence increase produced by both isoflurane and sevoflurane was eliminated by 5-hydroxydeanoate. Although propofol and pentobarbital showed no significant effects on flavoprotein oxidation, they both dose-dependently inhibited isoflurane-induced flavoprotein oxidation.     

Aluminofluoride- and Epidermal Growth Factor-Stimulated DNA Synthesis in MOB 3-4-F2 Cells

Abstract: In attempt to study the mechanism of F^?-induced, osteoblast-mediated bone formation, we tried to show the characteristics of Al-F complex-induced mitogenesis in osteoblastic cells. The MOB 3-4-F2 cell line, an osteoblast-like cell line derived from neonatal mouse calyaria, responded to F^? (1-2 mM) combined with Al³⁺ and epidermal growth factor (EGF, 0.01–10. ng/ml) with increased DNA synthesis. Of the several types of Al-F complexs, A1F₄^? is thought to act as a mitogenic factor. On the other hand, NaF at high concentrations (>2 mM) markedly decreased cell viability. The AlF₄^?-stimulated DNA synthesis at least with a delay of 48 hr, while EGF stimulated DNA synthesis within a few hours (4-6 hr). Both 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H-7) and staurosporine, inhibitors of protein kinase C (PKC), further enhanced DNA synthesis in AlF₄^?-treated cells, whereas 12-O-tetradecanoyl-13-acetate (TPA), an activator of PKC, decreased the DNA synthesis. In EGF-treated cells, staurosporine and TPA, but not H-7, decreased DNA synthesis. In addition, indomethacin, an inhibitor of cyclooxygenase, partly inhibited the EGF-induced mitogenesis, which, however, was restored by addition of PGE₂. AlF₄^? as well as EGF, stimulated the release of arachidonic acid and its metabolites. Indomethacin failed to inhibit the AlF₄^?-induced mitogenesis. Thus, the mitogenic response of MOB 3-4-F2 cells to F^? in the presence of Al³⁺ had the following characteristics: (1) it was effective over a narrow range, (2) it had a slow onset, (3) included a PKC-sensitive mechanism and (4) a PG(E₂)-independent mechanism. In contrast, a wide range of EGF concentrations rapidly stimulated DNA synthesis by a PKC-sensitive, PG(E₂)-dependent mechanism in these cells.     

Resonance Raman evidence for oxygen exchange between the FeIV = O heme and bulk water during enzymic catalysis of horseradish peroxidase and its relation with the heme-linked ionization.

Raman spectroscopic studies of compound II of horseradish peroxidase show that the oxygen atom in the FeIV = O group of the heme is rapidly exchanged in H2O at pH 7.0 but not in an alkaline solution (pH 11.0). This conclusion is based on studies of shift in the FeIV = O stretching mode of compound II in H2(18)O; further studies show that the FeIV = O heme is hydrogen-bonded to an amino acid residue of the protein in neutral solutions but not in the alkaline solution. Deprotonation of this residue takes place with the midpoint pH at 8.8 and accordingly corresponds to the so-called heme-linked ionization. It is concluded that this hydrogen-bonded proton plays an important part in the oxygen exchange mechanism. From this it seems clear that this hydrogen-bonded proton has an essential role in the acid/base catalysis of this enzyme and that alkaline deactivation of this enzyme can be attributed to the lack of a hydrogen-bonded proton at high pH.     

Molecular characteristics of serotype 3 Streptococcus pneumoniae isolates among community-acquired pneumonia patients in Japan

In order to understand the spread of the erythromycin-resistant serotype 3 Streptococcus pneumoniae clone in Japan, we have assessed the molecular characteristics of this clone. Among 156 S. pneumoniae isolates recovered from adults with community-acquired pneumonia between 2003 and 2005, 42 were serotype 3 and 40 were sequence type (ST) 180/Netherlands(3)-31 by multilocus sequence typing. Thirty-eight of the 40 ST 180 isolates had acquired resistance to erythromycin via the ermB gene. Although the ermB-positive ST180 clone isolates were more susceptible to penicillin and trimethoprim-sulfamethoxazole than ermB-positive non-ST180 isolates and contained a less mutated pbp1a or pbp2b gene, without a mefA gene, the ST180 clone was highly prevalent among ermB-positive isolates. Routine surveillance for the ST180 S. pneumoniae clone may soon become necessary.     

Low frequency of cervicocranial artery involvement in Japanese with renal artery fibromuscular dysplasia compared with that of Caucasians

Background

Fibromuscular dysplasia (FMD), which usually affects the renal artery, also affects the carotid, vertebral, and intracranial arteries. Previous studies have shown a high prevalence of concomitant renal artery and cervicocranial lesions in FMD patients. However, the analyzed subjects were mostly Caucasians in Western countries.

Method

We performed a retrospective analysis to examine the prevalence of cervicocranial vascular lesions in Japanese FMD patients with renal artery involvement at a single institution. The presence of cervicocranial lesions was evaluated by Doppler echography and magnetic resonance angiography. We compared this prevalence with that reported in the literature.

Result

Thirty-one Japanese FMD patients with renal artery lesions were studied. The mean age was 30?±?12 years, 71% were women, and 16% were smokers; all patients were Asians and had hypertension. Multifocal, tubular, and unifocal types of renal lesions were found in 52, 35, and 13% of patients, respectively. Bilateral renal lesions were found in 13% of patients. None of the patients had a cervical vascular lesion associated with FMD. Only two patients (8%) had a lesion in the intracranial artery, of which one was a known case of moyamoya disease.

Conclusion

These findings suggest that cervical artery involvement and intracranial artery involvement are not common in renal FMD patients in Japan, which is in contrast to the data reported for Caucasian patients in Western countries. Ethnic differences could influence the occurrence of cervicocranial lesions. A study with a larger sample size should be performed to validate these findings.