Observation of a large reaction cross section in the drip-line nucleus 22C.

Reaction cross sections (sigma(R)) for 19C, 20C and the drip-line nucleus 22C on a liquid hydrogen target have been measured at around 40A MeV by a transmission method. A large enhancement of sigma(R) for 22C compared to those for neighboring C isotopes was observed. Using a finite-range Glauber calculation under an optical-limit approximation the rms matter radius of 22C was deduced to be 5.4+/-0.9 fm. It does not follow the systematic behavior of radii in carbon isotopes with N < or = 14, suggesting a neutron halo. It was found by an analysis based on a few-body Glauber calculation that the two-valence neutrons in 22C preferentially occupy the 1s(1/2) orbital.

Mutations of carnitine palmitoyltransferase II (CPT II) in Japanese patients with CPT II deficiency.

Carnitine palmitoyltransferase II (CPT II) deficiency is an inherited disorder involving beta-oxidation of long-chain fatty acids. CPT II deficiency is a wide-spectrum disorder that includes a lethal neonatal form, an infantile form, and an adult-onset form. However, the ethnic characteristics and the relationship between genotype and clinical manifestation are not well understood. We investigated three non-consanguineous Japanese patients with CPT II deficiency and examined cell lines from 4 unrelated patients and 50 healthy donors. The CPT 2 gene was typed by direct DNA sequencing of polymerase chain reaction-amplified gene products. Case 1 (infantile form) was heterozygous for a phenylalanine to tyrosine substitution at position 383 (p.F383Y) and a novel valine to leucine substitution at 605 (p.V605L). Cases 2, 4, and 5 (infantile form) and case 3 (adult-onset form) were heterozygous for a single mutation at F383Y. Case 6 (adult-onset form) was compound heterozygous at the CPT 2 locus, with deletion of cytosine and thymine at residue 408, resulting in a stop signal at 420 (p.Y408fsX420), and an arginine to cysteine substitution at position 631 (p.R631C). Case 7 (adult-onset form) was homozygous for the p.F383Y mutation. In conclusion, we identified p.F383Y mutations in six of seven patients with CPT II deficiency and two novel variants of the coding gene: p.Y408fsX420 and p.V605L. These mutations differ from those in Caucasian patients, who commonly harbor p.S113L, p.P50H, and p.Q413fsX449 mutations; therefore, our data and those of other Japanese groups suggest that the p.F383Y mutation is significant in Japanese patients with CPT II deficiency.

Amelioration of insulin resistance in diabetic ob/ob mice by a new type of orally active insulin-mimetic vanadyl complex: bis(1-oxy-2-pyridinethiolato)oxovanadium(IV) with VO(S(2)O(2)) coordination mode.

Recently, we have shown that a newly synthesized vanadyl complex, bis(1-oxy-2-pyridinethiolato)oxovanadium(IV), VO(opt)(2), is a potent orally active insulin-mimetic in treating streptozotocin-induced diabetes in rats, with long-term action. In the present study, the anti-diabetic effect of VO(opt)(2) and its mechanism in ob/ob mice, an obese non-insulin-dependent diabetes mellitus (NIDDM) animal model, was investigated. In ob/ob mice, 15-day oral treatment with VO(opt)(2) resulted in a dose-dependent decrease in the levels of glucose, insulin and triglyceride in blood. VO(opt)(2) was also effective in ameliorating impaired glucose tolerance in ob/ob mice, when an oral glucose tolerance test was performed after treatment with VO(opt)(2). Tumor necrosis factor-alpha (TNF-alpha) is a key component of obesity-diabetes link, we therefore examined the attenuating effect of VO(opt)(2) on impaired insulin signal transduction induced by TNF-alpha. Elevated expression of TNF-alpha was observed in the epididymal and subcutaneous fat tissues of ob/ob mice. Incubation of 3T3-L1, mouse adipocytes, with TNF-alpha reduced the phosphorylation of insulin receptor substrate-1 (IRS-1), whereas VO(opt)(2) treatment resulted in an enhancement of IRS-1 phosphorylation, irrespective of the presence or absence of TNF-alpha. Overall, the present study demonstrates that VO(opt)(2) exerts an anti-diabetic effect in ob/ob mice by ameliorating impaired glucose tolerance, and furthermore, attenuates the TNF-alpha-induced decrease in IRS-1 phosphorylation in adipocytes. These results suggest that the anti-diabetic action of VO(opt)(2) is derived from an attenuation of a TNF-alpha induced impaired insulin signal transduction via inhibition of protein tyrosine phosphatase, providing a potential clinical utility for VO(opt)(2) in the treatment of NIDDM.

Alteration in expression profiles of a series of diabetes-related genes in db/db mice following treatment with thiazolidinediones.

We studied the effect of pioglitazone on the transcription of 42 genes associated with diabetes to examine the relationship between the antidiabetic action of thiazolidinediones (TZDs) and their ability to modulate transcription through their peroxisome proliferater-activated receptor (PPAR)-agonistic activity. Diabetic (db/db) mice were orally administered with pioglitazone for two weeks. Total RNA was prepared from liver, muscle and adipocytes and the quantity of mRNA was determined by comparative RT-PCR. The expression of diabetes-related genes was compared between lean and untreated db/db mice and between untreated and drug-treated db/db mice. The onset of diabetes was associated with a considerable alteration in the expression of a large number of diabetes-related genes. Treatment of db/db mice with pioglitazone modulated the expression of genes involved in the metabolism of glucose, lipids and lipoproteins. This included genes for phosphoenolpyruvate carboxykinase, beta-oxidation enzymes, lipoprotein lipase, apolipoprotein AI and uncoupling proteins. Most of the genes responsible for insulin signaling were unaffected. Administration of pioglitazone was also shown to induce PPARgamma expression in liver and muscle. It is therefore possible to hypothesize that TZDs may ameliorate diabetes through a mechanism of action involving a direct decrease in plasma glucose and triglyceride levels and improvements in free fatty acid-induced insulin resistance.

Establishment and characterization of a cisplatin-resistant human neuroblastoma cell line.

BACKGROUND: To investigate the mechanisms of cisplatin (CDDP)-resistance in neuroblastoma(NB), we established a CDDP-resistant human NB cell line, BM1R2. MATERIALS AND METHODS: We characterized BM1R2 in terms of the susceptibilities to other anticancer agents, MDR1 and MRP expression, MYCN amplification, intracellular gultathione-S-transferase(GST-pi), metallothionein(MT) and gultathione(GSH) levels, and immunocytochemical and cytogenetic features. RESULTS: When compared to parent BM1 line, BM1R2 exhibited a 17.0-fold resistance to CDDP and cross-resistance to other agents. MRP expression was only observed in BM1R2, whereas MDR1 was expressed in both lines. Notably higher intracellular GST-pi and MT levels were observed in BM1R2 cells. MYCN amplifications were 50 and 6 copies in BM1 and BM1R2, respectively, and additional aberrations were observed in chromosome 1 and 2 in BM1R2. CONCLUSION: It was suggested that GST-pi and MT could exert crucial roles on CDDP-resistance in our system. BM1R2 is of great interest for investigating the mechanisms of CDDP-resistance in NB.

Inhibitory effects of bifemelane on brain Ca2+ channel subtypes expressed in Xenopus oocytes.

Effects of the cerebroprotective agent bifemelane on voltage-dependent Ca2+ channel currents were evaluated in Xenopus oocytes expressing specific Ca2+-channel subtypes. Extracellular perfusion of bifemelane showed a dose-dependent blocking action on both N-type and Q-type Ca2+ channels, but not on cardiac L-type Ca2+ channels expressed in the oocytes, and the inhibitory action on Q-type current was stronger than that on N-type current. The time course of inhibition by bifemelane was comparatively slow; a 20-min perfusion with 1 microM bifemelane was required to reduce the amplitude of the Q-type current to 80% of the control level. When bifemelane was applied intracellularly, the potency and time-course of inhibition was equivalent to that caused by the perfusion of bifemelane. The bifemelane-induced inhibition was voltage-dependent but not use-dependent in Q-type channels since it was apparent at more depolarized potentials but not influenced by the interval of depolarization. These results suggest that bifemelane inhibits the opening of the specific Ca2+ channels located at nerve terminals to suppress excessive neurotransmitter release from neurons in some pathophysiological conditions such as ischemia.

Determination of lycopene, alpha-carotene and beta-carotene in serum by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry with selected-ion monitoring.

A selected-ion monitoring (SIM) determination of serum lycopene, alpha-carotene and beta-carotene by an atmospheric pressure chemical ionization mass spectrometry (APCI-MS) was developed. A large amount of serum cholesterols disturbed the SIM determination of carotenoids by contaminating the segment of interface with the LC-MS. Therefore, separation of carotenoids from the cholesterols was performed using a mixed solution of methanol and acetonitrile (70:30) as the mobile phase on a C18 column of mightsil ODS-5 (75 mm x 4.6 mm I.D.). The SIM determination was carried out by introducing only the peak portions of carotenoids and I.S. (squalene) by means of an auto switching valve. In the positive mode of APCI-MS, lycopene, alpha-carotene and beta-carotene were monitored at m/z 537 and I.S. was monitored at m/z 411. This method was linear for all analytes in the range of 15-150 ng for lycopene, 7-70 ng for alpha-carotene and 25-50 ng for beta-carotene. The detection limit of LC-APCI-MS-SIM for carotenoids was about 3 ng per 1 ml of serum (S/N = 3). The repeatabilities, expressed as C.V.s, were 10%, 8.4% and 5.3% for lycopene, alpha-carotene and beta-carotene, respectively. The intermediate precisions, expressed as C.V.s, were 11.2%, 8.8% and 6.5% for lycopene, alpha-carotene and beta-carotene, respectively.