Prevention of focal intimal hyperplasia in rat vein grafts by using a tissue engineering approach

The present study focused on the role of blood flow in the formation of focal intimal hyperplasia in vein grafts, as well as the development of an engineering approach that can be used to eliminate disturbed blood flow and prevent blood flow-related focal intimal hyperplasia. A rat vein graft model was constructed by interposing a jugular vein into the abdominal aorta with end-to-end anastomoses. Locally disturbed flow was identified by analyzing particle streak-lines in methyl salicylate-cleared and perfused vein grafts in vitro with a physiological Reynolds number. At day 10, 20, and 30 after surgery, focal intimal hyperplasia of the vein grafts was examined using a histological approach and the density of alpha-actin positive cells was determined using immunohistological and fluorescent approaches. Results showed that apparent eddy blood flow formed at the proximal, but not at the distal, end of the vein grafts due to graft-host diameter mismatch and local geometric distortions, and was associated with apparent focal intimal hyperplasia. The thickness of the alpha-actin positive layers of the proximal vein grafts was significantly higher than that of the distal grafts (192 +/- 27 vs. 94 +/- 18 microm, 278 +/- 55 vs. 124 +/- 20 microm, and 288 +/- 24 vs. 131 +/- 23 microm for day 10, 20. and 30, respectively). The density of the alpha-actin positive cells, however, was similar between the proximal and the distal regions (3569 +/- 361 vs. 3285 +/- 343 cells/mm2, 5540 +/- 650 vs. 5376 + 887 cells/mm2, and 5465 +/- 791 vs. 5278 +/- 524 cells/mm2 for day 10, 20, and 30, respectively). When eddy blood flow was eliminated by matching the graft-host diameters using a tissue engineering approach, the average thickness of the alpha-actin positive layers of the proximal (71 +/- 15, 86 +/- 16, and 85 +/- 14 microm for day 10, 20, and 30, respectively) and the distal vein grafts (68 +/- 13, 80 +/- 14, and 79 +/- 13 microm for day 10, 20, and 30, respectively) was reduced significantly. The density of the alpha-actin positive cells was also reduced significantly in the proximal (2946 +/- 359, 3261 +/- 295, 3472 +/- 599 cells/mm2 for day 10, 20, and 30, respectively) and in the distal regions (3151 +/- 511, 3466 +/- 687, 3593 +/- 688 cells/mm2 for day 10, 20, and 30, respectively). The thickness of the alpha-actin positive layers and the density of the alpha-actin positive cells were not significantly different between the proximal and distal regions of the engineered vein grafts at each observation time. These results suggest that eddy flow may develop in vein grafts and may facilitate the formation of focal intimal hyperplasia, and the vascular tissue engineering approach developed in this study may be used to prevent blood flow-related focal intimal hyperplasia in vein grafts.     

Synthesis of optically active (R)- and (S)-tai-ding-an(TDA) and their anti-HSV activity evaluation]

Tai-Ding-An (3-phthalimido-2-oxo-n-butyraldehyde bisthiosemicarbazone, TDA) is an antiviral drug first synthesized in this institute. In order to clarify the difference between the two enantiomeric isomers of TDA, (R)- and (S)-TDA were synthesized from (R)- and (S)-alanine, respectively, via the following steps: fusing with phthalic anhydride gave 2-phthalimido alanine(2a or 2b). The resulting acid was reacted with thionyl chloride to offer the corresponding acid chloride(3a or 3b), which was treated with diazomethane to give the diazoketone(4a or 4b). Bromination of the ketone with hydrobromic acid gave the key intermediate 3-phthalimido-2-oxo-1-bromobutanone (5a or 5b). Compound 5a or 5b was oxidized with DMSO to give 6a or 6b, which was directly condensed with thiosemicarbazide to afford the desired (R)- or (S)-TDA. (R)-TDA, (S)-TDA and (RS)-TDA have been tested in cell culture for anti-Herpes simplex virus I (HSV-1) and HSV-2 activities by plaque reducing method. All of them showed inhibitory effects on HSV-1 and HSV-2 replication with IC50 of 0.0296 mmol.L-1, 0.0359 mmol.L-1 and 0.0418 mmol.L-1 for HSV-1 and 0.88 mmol.L-1, 1.04 mmol.L-1 and 1.06 mmol.L-1 for HSV-2. Not much difference was found among these compounds either on IC50 or on therapeutic indexes.     

Phenotypic heterogeneity of mutational changes at a conserved nucleotide in 16 S ribosomal RNA

RNA sites that contain unpaired or mismatched nucleotides can be interaction sites for other macromolecules. C1054, a virtually universally conserved nucleotide in the 16 S (small subunit) ribosomal RNA of Escherichia coli, is part of a highly conserved bulge in helix 34, which has been located at the decoding site of the ribosome. This helix has been implicated in several translational events, including peptide chain termination and decoding accuracy. Here, we observed interesting differences in phenotype associated with the three base substitutions at, and the deletion of, nucleotide C1054. The phenotypes examined include suppression of nonsense codons on different media and at different temperatures, lethality conditioned by temperature and level of expression of the mutant rRNA, ribosome profiles upon centrifugation through sucrose density gradients, association of mutant 30 S subunits with 50 S subunits, and effects on the action of tRNA suppressor mutants. Some of our findings contradict previously reported properties of individual mutants. Particularly notable is our finding that the first reported 16 S rRNA suppressor of UGA mutations was not a C1054 deletion but rather the base substitution C1054A. After constructing deltaC1054 by site-directed mutagenesis, we observed, among other differences, that it does not suppress any of the trpA mutations previously reported to be suppressed by the original UGA suppressor. In general, our results are consistent with the suggestion that the termination codon readthrough effects of mutations at nucleotide 1054 are the result of defects in peptide chain termination rather than of decreases in general translational accuracy. The phenotypic heterogeneity associated with different mutations at this one nucleotide position may be related to the mechanisms of involvement of this nucleotide, the two-nucleotide bulge, and/or helix 34 in particular translational events. In particular, previous indications from other laboratories of conformational changes associated with this region are consistent with differential effects of 1054 mutations on RNA-RNA or RNA-protein interactions. Finally, the association of a variety of phenotypes with different changes at the same nucleotide may eventually shed light on speculations about the coevolution of parts of ribosomal RNA with other translational macromolecules.     

Iodized oil enhances the thermal effect of high-intensity focused ultrasound on ablating experimental liver cancer

The influence of the biological medium on high-intensity focused ultrasound (HIFU) therapy for ablating experimental liver cancer was studied. In study 1, the temperature rise in the focal zone in the presence of iodized oil or castor oil was observed in vitro. The results showed that HIFU with iodized oil produced a higher and faster temperature rise than did HIFU with castor oil, whether high-power (500 W/cm2) or relatively low-power (136 W/cm2) conditions were used (P = 0.0008 and P = 0.0004 respectively). With the excised liver samples, the temperature also rose higher and more rapidly after injection of iodized oil into the liver than when castor oil was injected (P = 0.0239), and the target liver tissue revealed more radically and extensive destruction with iodized oil than with castor oil. In study 2, 48 nude mice, bearing primary liver cancer LTNM4 implanted subcutaneously, were randomly divided into four groups. Group I (n = 12) were the controls, group II (n = 12) were injected with iodized oil alone, group III (n = 12) received HIFU treatment, and group IV (n = 12) were exposed to HIFU after iodized oil injection. Significant inhibition of tumor growth was seen in groups III and IV as compared with group I or group II (P < 0.05), the tumor growth inhibition rate on the 28th day after treatment being 87% and 93% respectively. Significantly improved survival was noted in groups III and IV compared with groups I and II (P < 0.05). Histologically, group IV showed more complete tumor necrosis than did group III. These data suggest that HIFU combined with iodized oil might have achieve of synergism, location and targeting in the treatment of liver cancer.     

Improving influenza immunization among healthcare workers

Infected cystic duplication of the duodenum is an unusual lesion. We report a case in which pre-operative MR imaging revealed a huge multicystic mass masquerading as a cystic lymphangioma or mesenteric cyst. The differential diagnosis of this unusual appearance is discussed.     

Systematic screening of the LDL-PLA2 gene for polymorphic variants and case-control analysis in schizophrenia

Systematic scans of the genome using microsatellite markers have identified chromosome 6p21.1 as a putative locus for schizophrenia in multiply affected families. There is also evidence from a series of studies for a role of abnormal phospholipid metabolism in schizophrenia. In light of these findings, and the role of platelet activating factor in neurotransmission and neurodevelopment, we have examined the LDL-PLA2 (plasma PAF acetylhydrolase, PAF-AH) gene, a serine dependent phospholipase that has been mapped by hybrid mapping to chromosome 6p21.1, as a positional candidate gene for schizophrenia. The gene was systematically screened using SSCP/HD analysis for polymorphisms associated with the disease. Four polymorphic variants were found within the gene and studied in a group of 200 schizophrenic patients and 100 controls. The variant in exon 7 (Iso195Thr) was found to be weakly associated with schizophrenia (p = 0.04) and the variant in exon 11 (Val379Ala) almost reached significance (p = 0.057). After correcting for multiple testing no significant associations were detected. Haplotype analysis combining pairs of polymorphisms also provided no evidence for association of this gene with schizophrenia in our sample of patients.     

Mechanism of intracellular calcium homeostasis in heat-exposed cardiomyocytes of rats

The activity of Ca(2+)-ATPase and calcium content were measured in sarcoplasmic reticulum (SR) and mitochrondria of myocardium from 40 adult female Wistar rats after exposure to 37 degrees C, 39 degrees C, 41 degrees C and 43 degrees C for 40 min respectively in vitro. The 45Ca uptake, intracellular free Ca2+ concentration ([Ca2+]i) and the relatively active calmodulin content were also observed in cultured cardiomyocytes from 120 neonatal Wistar rats under the same condition of heat exposure. The results showed that (1) the activity of Ca(2+)-ATPase of SR and mitochrondria of myocardium decreased after heat exposure, (2) the calcium content of SR and mitochrondria also showed a tendency of decrease with increase of exposure temperature, (3) the 45Ca uptake and mean [Ca2+]i increased, whereas the calmodulin content decreased. It is suggested that disturbances of intracellular calcium homeostasis may be responsible for cardiac functional disorder after heat exposure.     

Interleukin-8 concentration predicts the neutrophil count in middle ear effusion

Interleukin-8 (IL-8), a potent neutrophilic chemoattractant and inflammatory cytokine, is present in middle ear effusions (MEEs) of children with otitis media and is thought to be responsible for the accumulation of neutrophils in MEEs. We hypothesized that IL-8 concentration predicts the total number and proportion of neutrophils in MEEs. IL-8 concentration and total and differential cell counts were measured in MEEs of children undergoing tympanostomy tube placement for otitis media. IL-8 was present in 80 (98%) of 82 effusions. The mean +/- SEM value for IL-8 was 7342 +/- 847 pg/mL. The mean +/- SEM count and percentage of neutrophils were 1.34 x 10(6) +/- 3.44 x 10(5) and 70.6 +/- 3.1%, respectively. IL-8 concentrations correlated positively with the total number (r = +0.30; P = 0.02) and percentage of neutrophils (r = +0.32; P = 0.01) in the effusion. Additionally, purulent effusions had greater IL-8 concentrations (P = 0.003) and greater neutrophil count (P = 0.03) than mucoid or serous effusions. We conclude that IL-8 is consistently present in MEEs of children and IL-8 concentration predicts the total number and proportion of neutrophils. Furthermore, IL-8 concentration and the total number of neutrophils correlate positively with the type of effusion. These results support the hypothesis that IL-8 recruits neutrophils to the middle ear in MEEs.