Comparison of placental transfer of local anesthetics in perfusates with different pH values in a human cotyledon model

Purpose

We aimed to investigate the placental transfer of local anesthetics in perfusates with different pH values, using a dual-perfused human cotyledon model.

Methods

The dual-perfused human cotyledon model was prepared from placentas obtained following cesarean delivery (n = 5). Protein-free solution was perfused through both maternal and fetal arteries. Four amide-type local anesthetics (mepivacaine [Mep]; lidocaine [Lid]; bupivacaine [Bup]; and ropivacaine [Rop]) were added to the maternal perfusate at 1 µg·ml^?1. Three conditions were tested (stage 1, maternal pH 7.4, fetal pH 7.4; stage 2, maternal pH 7.4, fetal pH 6.9; and stage 3, maternal pH 6.9, fetal pH 6.9). Venous blood samples were collected from the fetal circuit after stabilization. The fetal vein/maternal artery concentration ratio (F/M ratio) of the local anesthetics was used as an index of placental transfer. The concentration of human chorionic gonadotropin (hCG) in the maternal vein was measured at the end of each stage.

Results

The F/M ratios in all stages were in the order of: Mep > Lid > Bup ≒ Rop. The F/M ratios of Mep were significantly higher than those of the other local anesthetics in all stages. The F/M ratios of Lid were higher than those of Rop in stages 2 and 3. The F/M ratios of Lid and Rop were higher in stage 2 than in stage 3. However, the differences between the F/M ratios in the three stages were not as large as expected from the basic uncharged ([B]) condition and pH gap. The concentration of hCG showed a time-dependent decrease with increasing stage (stage 1, 81.0 ± 58.9 mIU·ml^?1; stage 2, 57.4 ± 31.8 mIU·ml^?1; stage 3, 32.1 ± 19.7 mIU·ml^?1).

Conclusion

Our data clearly show that it is the basic uncharged concentration that mainly determines the placental transfer of amide-type local anesthetics with protein-free perfusate. This finding suggests that Rop and Bup can be used more safely than Mep in terms of placental transfer.     

Effect of weekend 5-aminosalicylic acid (mesalazine) enema as maintenance therapy for ulcerative colitis: results from a randomized controlled study

BACKGROUND: 5-aminosalicylic acid (5-ASA) is known to be effective in the treatment of active ulcerative colitis (UC). The aim of the current study was to investigate the effect of 5-ASA enemas, as a maintenance therapy for UC, when administered twice weekly as a weekend treatment regimen, compared to daily oral 5-ASA alone. We hypothesized that the weekend enema therapy would be better tolerated by patients who worked or attended school. METHODS: Between January 2004 and August 2005, patients with UC, in whom remission of the condition had just been induced, were randomly assigned to either: the weekend 5-ASA enema group (n=11), who received 1 g 5-ASA enemas twice a week on Saturday and Sunday plus oral 5-ASA 3 g/day for 7 days, or to the daily oral 5-ASA use only group (n=13), who received only oral 5-ASA 3 g/day for 7 days. The primary endpoint of the study was defined as the incidence of relapse. The study was stopped after 24 patients had been enrolled because an interim analysis showed a significant benefit of the weekend 5-ASA enema group. RESULTS: In the weekend enema group, 2 patients (18.2%) had relapses compared with 10 (76.9%) in the oral 5-ASA only group. The multivariate hazard ratio of relapse associated with weekend 5-ASA enema, relative to the oral alone group, was 0.19 (95% confidence interval, 0.04-0.94). CONCLUSIONS: This study demonstrated the beneficial effects of adding weekend 1 g 5-ASA enema to daily 3 g oral 5-ASA as maintenance therapy for UC.     

Establishment of external quality control program for hs-CRP and three-year follow-up of the performance for precision and accuracy

AIM: We established an external quality control (QC) program for high-sensitivity C-reactive protein (hs-CRP) for a collaborative epidemiological study.METHODS: External QC was performed 3 times in 3 years to follow hs-CRP performance for precision and accuracy.RESULTS: For precision, the mean coefficient of variation (CV) of the internal QC by 9 laboratories was 2.2% and 1.9% in the 1st and 2nd tests, respectively. The mean CV of the external QC by 4 laboratories was 2.7% in the three tests. The CV of both the internal and external QC satisfied the acceptable range specified by the AHA/CDC Scientific Statement, CV < 10%. For accuracy, the mean values of the 1st external QC by 9 laboratories were set as the consensus value and the acceptable range was set to within +/- 10% from it. The mean accuracy by 9 laboratories was 0.51% in the 2nd external QC. The mean accuracy by 4 laboratories was - 0.37% in the 3rd external QC. These findings demonstrated that the initial consensus value was valid in the continued external QC, and hs-CRP was stable for 3 years.CONCLUSION: We demonstrated both the precision and accuracy of hs-CRP by an external QC program applied for 3 years in a collaborative epidemiological study.     

Polymorphisms of apolipoprotein e and methylenetetrahydrofolate reductase in the Japanese population

AIM: The aim of this study is to analyze the effect of apolipoprotein E (apo E) and methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms on serum lipid and homocysteine levels in the general Japanese population. METHODS: We analyzed the polymorphisms in individuals randomly selected from among participants of Serum Lipid Survey 2000. RESULTS: The frequency of the epsilon2, epsilon3, and epsilon4 alleles of APOE was 4.2, 85.3, and 10.5%, respectively. Individuals with the genotype epsilon4/epsilon4 had the highest total and low-density lipoprotein (LDL) cholesterol levels, while those with epsilon2/epsilon2 had the lowest. Individuals with the epsilon2/epsilon2 and epsilon2/epsilon4 genotypes had higher remnant-like particles (RLP)-cholesterol levels than those with epsilon2epsilon3, epsilon3epsilon3, and epsilon3epsilon4. There was a trend for individuals with the epsilon2/epsilon4 and epsilon2/epsilon2 genotypes to have higher triglyceride levels, although the difference was not significant. The presence of the T allele in a MTHFR polymorphism (C667T) was associated with higher homocysteine levels, which is more prominent in men than in women. CONCLUSION: Thus in our large-scale analysis we have shown that RLP-cholesterol is better associated with, APOE genotype than triglyceride and the effect of the T allele on MTHFR polymorphism (C667T) homocysteine levels is more prominent in men than in women among Japanese.     

Initial impact of drug-eluting stents on coronary artery bypass grafting

The impact of drug-eluting stents (DES) on the characteristics and operative results of patients referred for coronary artery bypass grafting (CABG) was studied. We reviewed data from isolated CABG patients 24 months before (group A, n = 134) and 24 months after (group B, n = 98) the introduction of DES for clinical use at Teikyo University Hospital in Tokyo. Group B patients were significantly older than those of group A (66 +/- 9 versus 69 +/- 9 years old). The number of diseased vessels was significantly larger in group B (2.5 +/- 0.6 versus 2.7 +/- 0.5) and left main trunk disease decreased in group B (27% versus 17%). Preoperative IABP support was more frequent in group B (9% versus 17%) and beating heart surgery was significantly more frequent in group B (26% versus 59%). The number of grafts was similar in the 2 groups (3.2 +/- 1.4 versus 3.0 +/- 1.1). The operative mortality rates were 0.7% and 4.1% in group A and B, respectively. Incomplete revascularization followed by postoperative percutaneous coronary intervention (PCI) was performed in 11% and 12%, respectively, and all the patients survived surgery. The operative mortality rates for arrested heart and beating heart surgery were 2% and 2%, respectively. In conclusion, after the introduction of DES, more clinically ill patients were referred to CABG. Combination therapy consisting of CABG and PCI (Hybrid) may be a treatment of choice in critical patients.     

Involvement of Krüippel-like factor 6 （KLF6） mutation in the development of nonpolypoid colorectal carcinoma

AIM： To examine Kruppel-like factor 6 （KLF6） mutations in nonpolypoid-type tumors and alterations of K-ras, p53, and B-raf in relation between mutation and morphologic type, particularly nonpolypoid-type colorectal carcinomas.
METHODS： Fifty-five early nonpolypoid colorectal carcinomas were analyzed. Loss of heterozygosity （LOH） of KLF6 and p53 was determined by microsatellite assay. Mutations of KLF6, K-ras, and B-raf were examined by polymerase chain reaction-single-strand conformation polymorphism followed by direct sequencing. In LOH- positive and/or mutation-positive tumors, multiple （4-7） samples in each tumor were microdissected and examined for genetic alterations, p53 expression was evaluated by immunohistochemistry. RESULTS： LOH of KLF6 and p53 was found in 14 of 29 （48.3%） and 14 of 31 （45.2%） tumors, respectively. In tO of the 14 （71.4%） KLF6 LOH-positive tumors and 9 of the 14 （64.3%） p53 LOH-positive tumors, LOH was found in all of the microdissected samples. In 1 of the tO （10.0%） KLF6 LOH-positive tumors, a single missense mutation was identified. K-ras and B-raf mutations were found in 5 of 55 （9.1%） and 6 of 55 （10.9%） tumors, respectively. However, these mutations were detected only in subsets of microdissected tumor samples.
CONCLUSION： These data suggest that KLF6 and p53 mutations are involved in the development of nonpolypoid colorectal carcinoma, whereas K-ras and B-raf mutations are not.     

Enzymatic properties and localization of motopsin (PRSS12), a protease whose absence causes mental retardation

Motopsin (PRSS12) is a mosaic protease expressed in the central nervous system. Truncation of the human motopsin gene causes nonsyndromic mental retardation. Understanding the enzymatic properties and localization of motopsin protein in the central nervous system will help identify the molecular mechanism by which the loss of motopsin function causes mental retardation. Recombinant motopsin showed amidolytic activity against the synthetic substrate benzyloxycarbonyl-l-phenylalanyl-l-arginine 4-methyl-coumaryl-7-amide. Motopsin activated the single-chain tissue plasminogen activator precursor and exhibited gelatinolytic activity. This enzymatic activity was inhibited by typical serine protease inhibitors such as aprotinin, leupeptin, and (4-amidinophenyl) methanesulfonyl fluoride. Immunocytochemistry using anti-motopsin IgG revealed that both human and mouse motopsin proteins were distributed in discrete puncta along the dendrites and soma as well as axons in cultured hippocampal neurons. In the limbic system, including the cingulate and hippocampal pyramidal neurons and piriform cortex, high level of motopsin protein was expressed at postnatal day 10, but a very low level at 10-week-old mice. Motopsin and tissue plasminogen activator were co-expressed in the cingulate pyramidal neurons at postnatal day 10 and were distributed along dendrites of cultured pyramidal neurons. In cranial nuclei, a moderate level of motopsin protein was detected independently on the developmental stage. Our results suggest that motopsin has multiple functions, such as axon outgrowth, arranging perineuronal environment, and maintaining neuronal plasticity, partly in coordination with other proteases including tissue plasminogen activator.     

Role of p53 in neurotoxicity induced by the endoplasmic reticulum stress agent tunicamycin in organotypic slice cultures of rat spinal cord

The endoplasmic reticulum (ER) is important for maintaining the quality of cellular proteins. Various stimuli can disrupt ER homeostasis and cause the accumulation of unfolded or misfolded proteins, i.e., a state of ER stress. Recently, ER stress has been reported to play an important role in the pathogenesis of neurological disorders such as cerebral ischemia and neurodegenerative diseases, but its involvement in the spinal cord diseases has not been fully discussed. We conducted this study using tunicamycin (Tm) as an ER stress inducer for rat spinal cord in organotypic slice culture, a system that we have recently established. Tm was shown to induce ER stress by increased expression of GRP78. The viability rate of spinal cord neurons decreased in a dose-dependent manner with Tm treatment, and dorsal horn interneurons were more vulnerable to Tm-induced neurotoxicity. A p53 inhibitor significantly increased the viability of dorsal horn interneurons, and immunofluorescence studies showed nuclear accumulation of p53 in the dorsal horns of Tm-treated spinal cord slices. These findings suggest that p53 plays an important role in the killing of dorsal horn interneurons by Tm. In contrast, motor neurons were not protected by the p53 inhibitor, suggesting that the role of p53 may vary between different cell types. This difference might be a clue to the mechanism of the stress-response pathway and might also contribute to the potential application of p53 inhibitors for the treatment of spinal cord diseases, including amyotrophic lateral sclerosis.     

Identification of synaptic activity-dependent genes by exposure of cultured cortical neurons to tetrodotoxin followed by its withdrawal

Activity-dependent gene expression is one of the key mechanisms of synaptic plasticity that form the basis of higher order functions such as learning and memory. In the present study, we surveyed for activity-dependent genes by analyzing gene expression changes accompanying reversible inhibition of synaptic activity by tetrodotoxin (TTX) using two types of DNA microarrays; our focused oligo DNA microarray "Synaptoarray" and the commercially available high-density array. Cerebral cortical cells from E18 rat embryos were cultured for 14 days to ensure synaptogenesis, then treated with 1 muM TTX for 48 hr without detectable effect on cell viability. Synaptic density estimated by the amount of Synapsin I and Synaptotagmin I was decreased 21-24% by TTX treatment, but recovered to the control level 48 hr after TTX withdrawal. Comparison of gene expression profiles by competitive hybridization of fluorescently labeled cRNA from TTX-treated and control cells showed an overall downregulation of the genes on the Synaptoarray by TTX-treatment with different recovery rates after TTX withdrawal. With 16 representative genes, microarray data were validated by real-time PCR analysis. Genes most severely downregulated by TTX and upregulated above the control level at 5 hr after TTX withdrawal were munc13-1 (involved in docking and priming of synaptic vesicles) and Shank2 (involved in the postsynaptic scaffold). In addition, comprehensive screening at 5 hr after TTX withdrawal using high density arrays resulted in additional identification of Rgs2, a regulator of trimeric G-protein signaling, as an activity-dependent gene. These three genes are thus likely to be key factors in the regulation of synaptic plasticity. (c) 2007 Wiley-Liss, Inc.