Novel Preparation Method for Poly(l-lactide)-Based Block Copolymers: Extended Chain Crystallites as a Solid-State Macro-Coinitiator

A novel synthetic method for poly(L-lactide) (PLLA)-based diblock copolymers was developed by the use of PLLA extended chain crystallites (or crystalline residues) as a solid-state macro-coinitiator. In this study, we showed one example, i.e., a synthesis of diblock copolymer composed of a crystalline PLLA chain and an amorphous poly(DL-lactide) chain by ring-opening polymerization of DL-lactide initiated with stannous octoate (i.e., tin(II) 2-ethylhexanoate) in the presence of PLLA extended chain crystallites. The PLLA extended chain crystallites were prepared by hydrolytic degradation of crystallized PLLA films at 97 degrees C for 70 h. The chains inside the extended chain crystallites are expected to be protected from transesterfication reaction. Gel permeation chromatography, polarimetry, 1H NMR spectroscopy, wide-angle X-ray scattering, and differential scanning calorimetry revealed that the diblock copolymer poly(L-lactide-block-DL-lactide) was successfully prepared without significant transesterification.

Metabolism of the recently encountered designer drug, methylone, in humans and rats

The urinary metabolites of methylone in humans and rats were investigated by analysing urine specimens from its abuser and after administrating to rats with gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-electrospray ionization mass spectrometry (LC-ESI MS), using authentic standards. The time-course excretion profiles of methylone and its three metabolites in rats were further investigated after a single intraperitoneal dosing of 5 mg kg-1 methylone hydrochloride. Two major metabolic pathways were revealed for both humans and rats as follows: (1) side-chain degradation by N-demethylation to the corresponding primary amine methylenedioxycathinone (MDC), partly conjugated; and (2) demethylenation followed by O-methylation of either a 3- or 4-OH group on the benzene ring to produce 4-hydroxy-3-methoxymethcathinone (HMMC) or 3-hydroxy-4-methoxymethcathinone (3-OH-4-MeO-MC), respectively, mostly conjugated. Of these metabolites, HMMC was the most abundant in humans and rats. The cumulative amount of urinary HMMC excreted within the first 48 h in rats was approximately 26% of the dose, and the amount of the parent methylone was not more than 3%. These results demonstrate that the analysis of HMMC will be indispensable for proof of the use of methylone in forensic urinalysis.

Changes in regional cerebral blood flow during acute electroconvulsive therapy in patients with depression: positron emission tomographic study

BACKGROUND

Although electroconvulsive therapy (ECT) is widely used to treat psychiatric disorders such as depression, its precise neural mechanisms remain unknown.

AIMS

To investigate the time course of changes in cerebral blood flow during acute ECT.

METHOD

Cerebral blood flow was quantified serially prior to, during and after acute ECT in six patients with depression under anaesthesia using [(15)O]H(2)O positron emission tomography (PET).

RESULTS

Cerebral blood flow during ECT increased particularly in the basal ganglia, brain-stem, diencephalon, amygdala, vermis and the frontal, temporal and parietal cortices compared with that before ECT. The flow increased in the thalamus and decreased in the anterior cingulate and medial frontal cortex soon after ECT compared with that before ECT.

CONCLUSIONS

These results suggest a relationship between the centrencephalic system and seizure generalisation. Further, they suggest that some neural mechanisms of action of ECT are mediated via brain regions including the anterior cingulate and medial frontal cortex and thalamus.

Retrospective Study of the Effects of Cyclosporine in Comparison With Azathioprine on Renal Transplant Recipients Infected With Hepatitis C Virus

A recent report noted that cyclosporine (CsA) inhibits replication of the hepatitis C virus (HCV) in vitro. Thus, CsA may be a superior immunosuppressant for renal transplant recipients infected with HCV. In the present retrospective study, we assessed whether CsA reduced the clinical impact of HCV infection among those patients. A total of 405 renal transplants were performed between 1973 and 2005, of whom we studied 189 who received CsA-based immunosuppression (CsA group) vs 108 who received an azathioprine-based regimen (AZA group). There were 44 HCVAb carriers and 145 noncarriers in the CsA group, and 41 carriers and 67 noncarriers in the AZA group. Our results showed that patient survival rate was significantly worse among HCVAb carriers than among noncarriers, as the overall survival rates were 82.9% and 90.9%, respectively, after 10 years and 71.5% and 85.7%, respectively, after 20 years (P = .0003). Patient survival rates were also significantly worse in HCVAb carriers than in noncarriers in both groups, which were 83.2% and 95.0%, respectively, after 10 years, and 74.7% and 88.8%, respectively, after 20 years (P = .0147) in the CsA group, and 82.9% and 83.6%, respectively, after 10 years and 70.7% and 80.6%, respectively, after 20 years (P = .0171) in the AZA group. Conversely, no significant difference was seen in patient survival rate for HCVAb carriers between the two groups (83.2% vs 82.9% at 10 years, and 74.7% vs 70.7% at 20 years, P = .8195). Our results confirmed that HCV infection has a negative impact on the long-term survival of renal transplant patients who receive either a CsA-based or an AZA-based regimen, suggesting that CsA does not have a positive impact on HCV carriers.

Atypical spinal dural arteriovenous fistula with supply from the lateral sacral artery

We report a dural arteriovenous fistula (AVF) that developed at a site on the midline dorsal surface of the dura mater that had been damaged by repeated lumbar punctures. A 61-year-old male patient had undergone repeated lumbar punctures and discectomy for severe lumbago 40 years before the present admission. After surgery, the lumbago symptoms resolved. However, 30 years after the operation, he started to experience dysaesthesia, motor weakness in both legs, and urinary disturbance. Physical examination revealed bilateral leg weakness, diminished deep tendon reflexes in the patellar and Achilles tendons bilaterally, and decreased superficial sensation below L1. Magnetic resonance imaging revealed swelling with intramedullary high intensity and multiple flow voids around the conus and spinal cord on T(2)-weighted images, and adhesive arachnoiditis. Spinal angiography revealed an AVF between the left lateral sacral artery and the S1 radicular vein at the site of the previous operation. Surgery was conducted to carry out excision of the dural AVF at the shunting point, the arterialized intradural vein, and lysis of the arachnoiditis. This case of dural AVF may have been caused by repeated lumbar punctures.

A leptomycin B resistance gene ofSchizosaccharomyces pombeencodes a protein similar to the mammalian P-glycoproteins

Screening for leptomycin B (LMB)-resistant transformants in a gene library constructed in Schizosaccharomyces pombe with the chromosomal DNA of an LMB-resistant mutant of S. pombe and with multicopy plasmid pDB248' as the vector led to the isolation of a gene, named pmd1+, encoding a 1362-amino-acid protein. This protein showed great similarity in amino acid sequence to the mammalian P-glycoprotein encoded by the multidrug resistance gene, mdr, and the Saccharomyces cerevisiae a-factor transporter encoded by STE6. In addition, computer analyses predicted that the protein encoded by pmd1+ formed an intramolecular duplicated structure and each of the halves contained six transmembrane regions as well as two ATP-binding domains, as observed with the P-glycoproteins and the STE6 product. Consistent with this was that S. pombe cells containing the pmd1+ gene on a multicopy plasmid showed resistance not only to LMB but also to several cytotoxic agents. The pmd1 null mutants derived by gene disruption were viable and hypersensitive to these agents. All these data suggest that the pmd1+ gene encodes a protein that is a structural and functional counterpart of mammalian mdr proteins.

Effect of nifedipine on adiponectin in hypertensive patients with type 2 diabetes mellitus

Nifedipine, a dihydropyridine calcium antagonist, improves endothelial function in patients with hypercholesterolaemia by enhancing nitric oxide (NO) activity, and increases endothelial NO bioavailability by antioxidant mechanisms. We administered a long-acting nifedipine formulation (controlled release (CR) nifedipine: 20 mg/day) to hypertensive patients for 6 months. There were no other changes of drug treatment during therapy with CR nifedipine. Clinical and biochemical data obtained before and after CR nifedipine administration were compared. All markers were measured by enzyme-linked immunosorbant assay. The levels of soluble markers (soluble CD40 ligand, soluble P-selectin, and soluble E-selectin), microparticles (MP) (platelet-derived MP, monocyte-derived MP, and endothelial cell-derived MP), and adiponectin differed between the control group and the hypertension group. The levels of these markers were also different in hypertensive patients with and without type 2 diabetes compared with the control group. In the hypertensive patients with type 2 diabetes, all markers except adiponectin decreased significantly after 3 months of CR nifedipine treatment. In contrast, markers were unchanged in the hypertensive patients without type 2 diabetes. Adiponectin was increased after 6 months of CR nifedipine treatment in hypertensive patients with type 2 diabetes. The effects of CR nifedipine on platelet/monocyte activation and adiponectin levels demonstrated in the present study indicate the potential effectiveness of calcium antagonist therapy for hypertensive patients with type 2 diabetes.

Cortical trapping of alpha-[(11)C]methyl-l-tryptophan, an index of serotonin synthesis, is lower in females than males

One neural system that may exhibit gender differences is serotonin (5-HT), a neurotransmitter implicated in the regulation of mood, cognitive processes, and impulse-control. However, most of the available evidence of gender-related differences in this system has been indirect and at times contradictory. The objective of the present study was to follow up on preliminary evidence that there are gender differences in brain regional 5-HT synthesis, as measured by trapping of alpha-[(11)C]methyl-l-tryptophan (alpha-[(11)C]MTrp). Sixty-minute dynamic scans were performed in healthy volunteers, 28 women and 31 men. Functional images of the brain trapping constant, used as a proxy for 5-HT synthesis, which correlate in the rat brain with tryptophan's conversion into 5-HT, were transferred to the standardized 3D space. The voxel based comparison was performed by Statistical Parametric Mapping with proportional normalization. There was lower normalized alpha-[(11)C]MTrp trapping in females than males throughout much of the cerebral cortex, including the left middle frontal gyrus, the bilateral inferior frontal gyrus, the bilateral precentral gyrus, the left supramarginal gyrus, the bilateral inferior parietal lobule, the left superior temporal gyrus, the bilateral posterior cingulate gyrus, and the bilateral precuneus. There were no regions in which the normalized trapping was significantly higher in females than in males. Gender differences in sub-cortical sites were not found. Women, compared to men, may have lower rates of this tracer trapping, used as a proxy for 5-HT synthesis, throughout much of the cerebral cortex which is likely related to differences in 5-HT synthesis because relative differences in the normalized trapping should be the same as those in 5-HT synthesis. These differences may be related, at least in part, to previously suggested gender differences in affect, cognitive processes, and susceptibility to 5-HT-related neuropsychiatric and neurological disorders.

Genetic analysis of HLA, NA and HPA typing in type 2 diabetes and ASO

We examined the genetic status of human leucocyte antigens (HLA), human platelet alloantigens (HPA) and neutrophil-specific antigens (NA) in patients with type 2 diabetes mellitus and diabetic arteriosclerosis obliterans (ASO). To our knowledge, the present study is the first report showing the relationship among three genetic factors in type 2 diabetes mellitus and ASO patients. HLA typing was performed by the polymerase chain reaction (PCR)-restriction fragment length polymorphism method. HPA-typing and NA-typing were by a PCR-sequence-specific primer method. The incidence of HLA-DRB1*1501 was found to be significant in type 2 diabetes and non-diabetic, particularly ASO-positive patients, compared to control subjects. There were no differences in NA1/NA2 between the control and diabetic or non-diabetic ASO groups. However, the frequency of NA2/NA2 in ASO-positive diabetes and non-diabetic ASO patients was significantly higher than controls. The a/b genotype of HPA-5a/5b was significantly lower in type 2 diabetes and non-diabetic ASO-positive patients than in controls. These findings suggest that genetic studies of HLA, NA and HPA could be useful to understand the pathogenesis of type 2 diabetes and ASO.

Accumulation of mitochondrial DNA mutation with colorectal carcinogenesis in ulcerative colitis

We recently reported that oxidative stress elicited by chronic inflammation increases the mutation of mitochondrial DNA (mtDNA) and possibly correlates with precancerous status. Since severe oxidative stress is elicited in the colorectal mucosa of individuals with ulcerative colitis (UC), the possible occurrence of an mtDNA mutation in the inflammatory colorectal mucosa and colitic cancer was investigated. Colorectal mucosal specimens were obtained from individuals with UC with and without colitic cancer and from control subjects. The frequency of mtDNA mutations was higher in colorectal mucosal specimens from patients with UC than that from control subjects. The levels of 8-hydroxy-2′-deoxyguanosine, a DNA adduct by reactive oxygen species, were significantly higher in UC than in control. Specimens from patients with colitic cancer contained a significantly higher number of mtDNA mutations. The present observations suggest that the injury followed by the regeneration of colorectal mucosal cells associated with chronic inflammation causes accumulation of mtDNA mutations. The increased instability of genes, including those on the mtDNA, is consistent with the high and multicentric incidence of colorectal cancer in individuals with UC. Thus, analysis of mtDNA could provide a new criterion for the therapeutic evaluation, and may be useful for the prediction of risk of carcinogenesis.