The complete mitochondrial genome sequence of Sogatella furcifera (Horváth) and a comparative mitogenomic analysis of three predominant rice planthoppers

The white-backed planthopper (WBPH), Sogatella furcifera (Horváth), is one of the most destructive pests of rice crops in many Asian countries. Using long-PCR and shotgun library methods, we sequenced the entire mitochondrial genomes (mt-genomes) of two WBPH individuals. Total lengths of the mt-genome of the two WBPH individuals were 16,612 bp and 16,654 bp with an identical AT content of 76.19%. Among the 13 protein coding genes (PCGs), only nad5 used an atypical initiation codon GTG. Most of the tRNA genes had the typical cloverleaf secondary structure except that the dihydrouridine (DHU) arms in two trnS genes and the TΨC arm of trnG gene did not form a stable stem-loop structure. Similar to the brown planthopper (BPH), Nilaparvata lugens (Stål), and the small brown planthopper (SBPH), Laodelphax striatellus (Fallén), some extraordinary features were observed in the WBPH mt-genome. These include similar gene rearrangement pattern, unusually short length of the atp8 gene and variable numbers of tandem repeat (VNTR) structure in control region. Interestingly, the same tandem repeat unit with stable secondary structure appeared in two different planthoppers, WBPH and SBPH, which belong to two different genera of the Delphacidae. This peculiar feature provides a direct evidence for the close relationship between the two planthoppers and updates our understanding of the evolutionary characteristics of mitochondrial control region. Comparison with two other predominant rice planthoppers (BPH and SBPH) revealed that different PCGs of mitochondria exhibit different evolutionary patterns.

The complete mitochondrial genomes of two rice planthoppers, Nilaparvata lugens and Laodelphax striatellus: conserved genome rearrangement in Delphacidae and discovery of new characteristics of atp8 and tRNA genes

Background

Nilaparvata lugens (the brown planthopper, BPH) and Laodelphax striatellus (the small brown planthopper, SBPH) are two of the most important pests of rice. Up to now, there was only one mitochondrial genome of rice planthopper has been sequenced and very few dependable information of mitochondria could be used for research on population genetics, phylogeographics and phylogenetic evolution of these pests. To get more valuable information from the mitochondria, we sequenced the complete mitochondrial genomes of BPH and SBPH. These two planthoppers were infected with two different functional Wolbachia (intracellular endosymbiont) strains (wLug and wStri). Since both mitochondria and Wolbachia are transmitted by cytoplasmic inheritance and it was difficult to separate them when purified the Wolbachia particles, concomitantly sequencing the genome of Wolbachia using next generation sequencing method, we also got nearly complete mitochondrial genome sequences of these two rice planthoppers. After gap closing, we present high quality and reliable complete mitochondrial genomes of these two planthoppers.

Results

The mitogenomes of N. lugens (BPH) and L. striatellus (SBPH) are 17, 619 bp and 16, 431 bp long with A + T contents of 76.95% and 77.17%, respectively. Both species have typical circular mitochondrial genomes that encode the complete set of 37 genes which are usually found in metazoans. However, the BPH mitogenome also possesses two additional copies of the trnC gene. In both mitochondrial genomes, the lengths of the atp8 gene were conspicuously shorter than that of all other known insect mitochondrial genomes (99 bp for BPH, 102 bp for SBPH). That two rearrangement regions (trnC-trnW and nad6-trnP-trnT) of mitochondrial genomes differing from other known insect were found in these two distantly related planthoppers revealed that the gene order of mitochondria might be conservative in Delphacidae. The large non-coding fragment (the A+T-rich region) putatively corresponding responsible for the control of replication and transcription of mitochondria contained a variable number of tandem repeats (VNTRs) block in different natural individuals of these two planthoppers. Comparison with a previously sequenced individual of SBPH revealed that the mitochondrial genetic variation within a species exists not only in the sequence and secondary structure of genes, but also in the gene order (the different location of trnH gene).

Conclusion

The mitochondrial genome arrangement pattern found in planthoppers was involved in rearrangements of both tRNA genes and protein-coding genes (PCGs). Different species from different genera of Delphacidae possessing the same mitochondrial gene rearrangement suggests that gene rearrangements of mitochondrial genome probably occurred before the differentiation of this family. After comparatively analyzing the gene order of different species of Hemiptera, we propose that except for some specific taxonomical group (e.g. the whiteflies) the gene order might have diversified in family level of this order. The VNTRs detected in the control region might provide additional genetic markers for studying population genetics, individual difference and phylogeographics of planthoppers.

Various infection status and molecular evidence for horizontal transmission and recombination of Wolbachia and Cardinium among rice planthoppers and related species

Wolbachia and Cardinium are widely distributed and are considered important for their ability to disturb reproduction and affect other fitness-related traits of their hosts. By using multilocus sequence typing (MLST), RFLP (restriction fragment length polymorphism) and 16S ribosomal DNA gene sequencing methods, we extensively surveyed Wolbachia and Cardinium infection status of four predominant rice planthoppers and one kind of leafhopper in different rice fields. The results demonstrated that Sogatella furcifera (Horváth) and Laodelphax striatellus (Fallén) were infected with the same Wolbachia strain (wStri), while Nilaparvata lugens (Stål) and its closely related species Nilaparvata muiri China were infected with two phylogeneticlly distant strains, wLug and wMui, respectively. Three new Wolbachia strains (provisionally named wMfas1, wMfas2 and wMfas3) were detected in the leafhopper Macrosteles fascifrons (Stål). Only S. furcifera was co-infected with Cardinium, which indicated that the distribution of Cardinium in these rice planthoppers was narrower than that of Wolbachia. Unambiguous intragenic recombination events among these Wolbachia strains and incongruent phylogenetic relationships show that the connections between different Wolbachia strains and hosts were more complex than we expected. These results suggest that horizontal transmission and host associated specialization are two factors affecting Wolbachia and Cardinium infections among planthoppers and their related species.

Diversity of Wolbachia in natural populations of spider mites (genus Tetranychus): evidence for complex infection history and disequilibrium distribution

Wolbachia are endosymbiotic bacteria that commonly infect arthropods and cause reproductive disorders in host. Within several Tetranychus species, Wolbachia have been detected and shown to affect their reproduction. However, little is known about their transmission and distribution patterns in natural populations of Tetranychus species. Here, we used multilocus sequence typing to confirm Wolbachia infection status and examined the relationship between Wolbachia infection status and host phylogeny, mitochondrial diversity, and geographical range in five Tetranychus species (Tetranychus truncatus, Tetranychus urticae, Tetranychus pueraricola, Tetranychus phaselus, and Tetranychus kanzawai) from 21 populations in China. The prevalence of Wolbachia within the five Tetranychus species ranged from 31.4 to 100 %, and the strains were remarkably diverse. Together, these observations indicate that Wolbachia was introduced to these populations on multiple separate occasions. As in other arthropods, the same Tetranychus species can accommodate very different strains, and identical Wolbachia occasionally infect different species. These observations suggest that Wolbachia are transmitted both vertically and horizontally. Horizontally, transmission is probably mediated by the host plants. The distribution patterns of Wolbachia were quite different among populations of the same species, suggesting that the dynamics of Wolbachia in nature may be affected by ecological and other factors.

Molecular cloning and characterization of the pseudorabies virus US1 gene

Using polymerase chain reaction, a 1050-bp sequence of the US1 gene was amplified from the pseudorabies virus (PRV) Becker strain genome; identification of the US1 gene was confirmed by further cloning and sequencing. Bioinformatics analysis indicated that the PRV US1 gene encodes a putative polypeptide with 349 amino acids. The encoded protein, designated PICP22, had a conserved Herpes_IE68 domain, which was found to be closely related with the herpes virus immediate early regulatory protein family and is highly conserved among the counterparts encoded by Herpes_IE68 genes. Multiple nucleic acid sequence and amino acid sequence alignments suggested that the product of PRV US1 has a relatively higher homology with ICP22-like proteins of genus Varicellovirus than with those of other genera of Alphaherpesvirinae. In addition, phylogenetic analysis showed that PRV US1 has a close evolutionary relationship with members of the genus Varicellovirus, especially Equid herpes virus 1 (EHV-1), EHV-4 and EHV-9. Antigen prediction indicated that several potential B-cell epitopes are located in PICP22. Also, subcellular localization analysis demonstrated that PICP22 is predominantly located in the cytoplasm, suggesting that it might function as a cytoplasmic-targeted protein.

Prognostic significance of PUMA in pancreatic ductal adenocarcinoma

OBJECTIVES

To investigate retrospectively whether alterations of p53 upregulated mediator of apoptosis (PUMA) protein levels and somatic mutations of the PUMA gene are characteristic of pancreatic ductal adenocarcinoma (PDAC).

METHODS

Immunohistochemical analyses of PUMA were performed in pancreatic tumour tissue samples, and paired normal pancreatic tissue samples, from patients with PDAC. Apoptosis was detected using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labelling assay.

RESULTS

A total of 70 patients with PDAC had samples available; 49 cases (70.0%) had high PUMA protein levels. PUMA was not detected in paired normal tissue samples. Significantly higher levels of PUMA protein were detected in low-grade tumours (tumour -node-metastasis stages I and II), compared with higher grade (stage III) tumours. Of the PDAC cases, the mean apoptosis index value for PUMA-positive specimens was significantly higher than that for PUMA-negative specimens. Overall survival was significantly associated with PUMA immunoreactivity.

CONCLUSIONS

High levels of PUMA in PDAC tumour cells suggest that PUMA expression may play a role in pancreatic tumourigenesis.

Tripartite associations among bacteriophage WO, Wolbachia, and host affected by temperature and age in Tetranychus urticae

A phage density model of cytoplasmic incompatibility (CI), which means lytic phages reduce bacterial density associated with CI, significantly enhances our understanding of the tripartite associations among bacteriophage WO, Wolbachia and host. However, WO may alternate between lytic and lysogenic life cycles or change phage production under certain conditions including temperature, host age and host species background. Here, extreme temperatures can induce an alteration in the life cycle of WO and change the tripartite associations among WO, Wolbachia and CI. Based on the accumulation of the WO load, WO can transform into the lytic life cycle with increasing age. These findings confirmed that the environment plays an important role in the associations among WO, Wolbachia and host.

Wolbachia strengthens cardinium-induced cytoplasmic incompatibility in the spider mite Tetranychus piercei McGregor

Wolbachia and Cardinium are maternally inherited intracellular bacteria that can manipulate the reproduction of their arthropod hosts, such as by inducing cytoplasmic incompatibility (CI). Although the reproductive alteration induced by Wolbachia or Cardinium have been well investigated, the effects of these two endosymbionts co-infecting the same host are poorly understood. We found that Tetranychus piercei McGregor is naturally infected with Wolbachia and Cardinium. We performed all possible crossing combinations using naturally infected and cured strains, and the results show that Wolbachia induced a weak level of CI, while Cardinium-infected and doubly infected males caused severe CI. Wolbachia and Cardinium could not rescue CI each other; however, Wolbachia boosted the expression of Cardinium-induced CI. Quantitative PCR results demonstrated that CI was associated with the infection density of Wolbachia and Cardinium.

Investigating the spatial-temporal variation of nitrogen cycling in an urban river in the North China Plain

Urban rivers are essential in retaining nutrients, but little is known about nitrogen cycling in these rivers in semiarid areas. We measured chemical and isotopic compositions of ammonium (NH4(+)-N) and nitrate (NO3(-)-N) to investigate spatial-temporal variation of nitrogen cycling in the Fuhe River in the North China Plain. Nitrogen pollution in the river was mainly induced by extra NH4(+)-N inputs which come from the discharges of urban sewage and effluents of wastewater treatment plants in upstream. NH4(+)-N obtained from decomposing organic matter of sediments can diffuse into the overlying water. Intense nitrification then occurs at the terrestrial-aquatic interface. Due to less vegetation in spring and autumn, loss of NH4(+)-N is mainly caused by nitrification. In contrast, significant NH4(+)-N is absorbed by plants in summer. NO3(-)-N generated from nitrification can be denitrified during the study period. The highest NO3(-)-N loss (about 86.3%) was observed in summer. The contribution of NO3(-)-N loss due to denitrification is 44.6%. The remaining 55.4% is due to plant uptake. The results suggested that nitrogen cycling in the river is related to temperature and dry-wet cycles. And vegetation restoration along the river could benefit the incremental improvements to the aquatic ecosystem.

Population dynamics of noncytoplasmic incompatibility-inducing Wolbachia in Nilaparvata lugens and its effects on host adult life span and female fitness

Wolbachia are bacteria that live intracellularly in a wide variety of arthropods. They are maternally inherited and can affect both reproduction and fitness of its host. When infected males mate with uninfected females or females infected by a different Wolbachia strain, there is often a failure of karyogamy, which is usually attributed to cytoplasmic incompatibility (CI). We measured the strength of CI induced by Wolbachia and the fitness effects in three Chinese populations of the brown planthopper Nilaparvata lugens from Hainan, Yunnan, and Guangxi provinces, respectively. No evidence for CI was found in any of the populations, whereas an enhanced fecundity and shortened longevity were observed only in the Hainan population. The infection density was significantly higher in the Hainan population than in the Guangxi population. The Wolbachia strain infecting the three populations appeared to be the same based on the nucleotide sequence of the wsp gene. Therefore, the variable effects of Wolbachia on host fitness seem to be the result of differences in the host genetic background and Wolbachia infection density. The ability of the non-CI-inducing Wolbachia to maintain themselves in their hosts may be attributed to their positive effects on host fecundity and efficient maternal transmission.

Expression characteristics of heparanase in colon carcinoma and its close relationship with cyclooxygenase-2 and angiogenesis

BACKGROUND/AIMS

Heparanase (HPA) influences tumourigenesis and tumour progression by various mechanisms, including angiogenesis. Cyclooxygenase-2 (COX-2) was strongly correlated with microvessel density, and that COX-2 expression is up-regulated by HPA in esophageal cancer. In this study, we examined the relationship between HPA expression and that of COX-2 in colon carcinoma. The aim of this study was to determine whether the expression of HPA is related to the angiogenesis in colorectal cancer and whether it could be involved in clinical behaviour of colon carcinoma.

METHODOLOGY

HPA and COX-2 was analyzed with Immunohistochemistry and Western blot. Microvessels in colon carcinoma were examined by using anti-CD34 antibody. Statistical analysis was applied to test for the prognostic and diagnostic associations.

RESULTS

Immunohistochemistry revealed that HPA was expressed at low level in normal colonic mucosa (4/78, 5.1%), but at higher level in tumor tissues (63/78, 80.7%) and closely correlated with tumor lymph node metastasis (p < 0.05). This result was further confirmed by Western blot analysis. Furthermore, carcinomas with high HPA expression demonstrated high COX-2 expression and high MVD (microvesseldensity) labelled with CD34. In addition, mortality was higher in patients with HPA+ phenotype and HPA was an independent predictor of overall survival (p < 0.05).

CONCLUSIONS

Our findings indicated that HPA might be an important biomarker for malignant transformation and be involved in promoting colon carcinoma metastasis by increasing angiogenesis.

[Expression of human pituitary tumor transforming gene 1 in colorectal cancer detected with real-time fluorescent quantitative PCR and its clinical significance]

BACKGROUND & OBJECTIVE

Although human pituitary tumor transforming gene 1 (hPTTG1) is overexpressed in malignant tumors such as colorectal cancer, its correlation to clinicopathologic parameters and its value in diagnosis and prognosis prediction of colorectal cancer are still not clear. We investigated the expression of hPTTG1 in colorectal cancer tissues, and elucidated its correlation to some clinicopathologic parameters of colorectal cancer.

METHODS

The expression of hPTTG1 in 60 specimens of colorectal cancer and corresponding noncancerous tissues were examined with real-time fluorescent quantitative polymerase chain reaction, and its correlation to seven clinicopathologic parameters were analyzed.

RESULTS

The mRNA level of hPTTG1 was significantly higher in colorectal cancer tissues than in corresponding noncancerous tissues (0.42+/-0.07 vs. 0.03+/-0.01, P<0.001), significantly higher in colorectal cancer tissues with serum CEA level of > 5 ng/mL than in those with CEA of < 5 ng/mL (22.79+/-7.42 vs. 9.34+/-2.61, P<0.001), significantly higher in colorectal cancer tissues with diameter of > or = 3.5 cm than in those with diameter of < 3.5 cm (15.80+/-8.80 vs. 10.91+/-5.22, P<0.05), significantly lower in Dukes'A, B tumors than in Dukes' C, D tumors (9.03+/-0.35 and 9.58+/-2.93 vs. 15.88+/-8.09 and 25.69+/-7.67, P<0.001), and significantly higher in colorectal cancer tissues with lymph node metastasis (17.63+/-8.47), liver metastasis (31.07+/-4.10) and other organ metastasis (22.78+/-6.39) than in those without metastasis (11.15+/-6.65) (P<0.001). hPTTG1 expression had no relationship with patients' age, sex and histological type (P>0.05).

CONCLUSIONS

hPTTG1 is overexpressed in colorectal cancer. It is closely related to the progression of colorectal cancer, and may be helpful for prognosis prediction of colorectal cancer.

Construction of FCU1 recombinant adenovirus vector and its killing effect on colon cancer cells

AIM: To construct a recombinant adenovirus vector containing fusion suicide gene FCU1, and study the cytotoxic effect of prodrug 5-FC on colon cancer cells.

METHODS: Restriction fragment of FCU1 was inserted into pDC316 vector with EcoRⅠ and SalⅠ. Recombinant plasmid pDC316-FCU1 was confirmed by restriction enzyme digestion and sequencing. Thereafter, pDC316-FCU1 was cotransfected with adenovirus backbone pBHG into 293 cells to establish the recombinant adenovirus Ad5-FCU1 by homologous recombination. The cytotoxic effect of prodrug 5-FC on the infected HCT116 cells was determined with MTT assay.

RESULTS: Recombinant plasmid pDC316-FCU1was constructed successfully. After pDC316-FCU1 together with adenovirus backbone pBHG was cotransfected into 293 cells, significant virus plaques were observed, which showed the successful homologous recombination and virus packaging in 293 cells. The titer of the purified Ad-FCU1 was 2 × 10¹² PFU/L. Nontoxic prodrug 5-FC has significant cytotoxic effect on HCT116 cells infected with pAd5-FCU1. The survival of HCT116/FCU1 cells was minimal, while that of the control cells was close to 90%, when 5-FC was used at 100 μmol/L.

CONCLUSION: Recombinant adenovirus Ad5-FCU1 containing fusion suicide gene FCU1 is established successfully, which has significant killing effect on colon cancer cells in vitro.

Expression of human pituitary tumor transforming gene 1 in colorectal cancer and its clinical significance

AIM: To investigated the expression of human pituitary tumor transforming gene 1 (hPTTG1) protein in colorectal cancerous tissues and to analyze its relationship with clinicopathological parameters so as to gain more experimental evidence for hPTTG1's clinical value in colorectal cancer diagnosis and relapse.

METHODS: Sixty colorectal cancer samples and their corresponding noncancerous tissues were examined for hPTTG1 protein expression using immunohistochemical staining and Western blotting analysis. Subsequently, we also studied the relationship between seven clinicopathological parameters and hPTTG1 protein expression.

RESULTS: Of 60 colorectal tissue samples, 50 samples of hPTTG1 protein expression were positive (93.3%), but only 8 corresponding noncancerous tissues were positive and all weakly positive (13.3%) (c² = 77.13, P < 0.001). There was a significant correlation between hPTTG1 mRNA expression and serum CEA level, and CEA ≥ 5 mg/L was significantly higher than CEA < 5 mg/L (c² = 30.886, P < 0.001); hPTTG1 gene was expressed significantly higher in Dukes C, D stages than in Dukes A, B stages (c² = 9.87, P < 0.001), and significantly higher in colorectal cancer with the lymph node invasion, liver or other organs metastasis than no invasion (c² = 9.87, P < 0.001). The hPTTG1 expression was not correlated with age, sex, tumor size or histologic types.

CONCLUSION: The hPTTG1 is overexpressed in and closely correlated with the progress of colorectal cancer, therefore hPTTG1 expression may be helpful for the judgement of the prognosis for colorectal cancer patients.

[MRI analysis of non-traumatic multiple vertebral collapse in aged people]

OBJECTIVE

To evaluate the MRI in the differential diagnosis of acute non-traumatic vertebral collapse.

METHODS

Sixty-eight cases were retrospected. All cases were studied with sagittal T1-weighted MR images, T2-weighted MR images, gadolinium-enhanced T1-weighted MR images, and axial T1-weighted MR images. Twelve of 68 were performed extra coronal T1-weighted MR images and 22 with additional axial gadolinium-enhanced T1-weighted images.

RESULTS

The causes of vertebral collapse were: (1) osteoporosis (n = 31), their images showed retropulsion of bony fragments of collapsed vertebral body which kept the normal signal into the spinal canal as the distinctive sign; (2) metastatic tumor (n = 30), their images showed destructions of pedicles of vertebral and epidural mass as the distinctive sign, and hyperintense or mixed hyperintense signal on T2WI and enhanced T1WI of compressed vertebrae; and (3) multiple myeloma (n = 7), their images showed long T1WI and long T2WI, without destruction of pedicle and epidural mass in compressed vertebrae.

CONCLUSION

MRI is useful to the differentiations of the non-traumatic vertebral collapse in aged.

Effects of salvianolic acid A on oxygen radicals released by rat neutrophils and on neutrophil function

Salvianolic acid A (Sai A) has demonstrated potent antioxidant activity in previous studies. In the present study, the effects of Sai A on oxygen radicals released by rat neutrophils and on neutrophil function were investigated. Superoxide anion assayed by the nitroblue tetrazolium test and hydrogen peroxide detected with redox of scopoletin were scavenged concentration dependently by Sai A in n-formyl-methionyl-leucylphenylalanine (fMLP)- and phorbol myristate acetate (PMA)-stimulated rat neutrophils. Hydroxyl radicals generated in PMA-stimulated neutrophils, measured by HPLC, also were scavenged significantly by Sai A, whereas Sai A showed no significant effects on chemotaxis toward fMLP and phagocytosis of latex beads by rat neutrophils. In addition, the intracellular free calcium and cyclic nucleotide levels of neutrophils, when stimulated by fMLP, were not affected by Sai A. These results suggest that Sai A could significantly scavenge oxygen radicals released by activated neutrophils without affecting their functional ability.

[Effects of 2-(p-dimethylaminostyryl) pyridine methycholide (DSPM-Ci) on ECG, left atrium contractivity and on papillary muscle action potentials]

The effects of DSPM-Cl on ECG in rats, on the dose-effect curve in guinea pig left atria and on the fast action potential (AP), high-K+ depolarized slow action potential (SAP) in guinea pigs papillary muscle were examined electrophysiologically. DSPM-Cl (2 mg.kg-1) showed significant nagative frequency, negative conductivity effect, and prolonged the PP and PR interval. DSPM-CI (30-50 mumol.L-1) was shown to inhibit left atria contractility and shift the concentration-response curve of Iso and CaCl2 to the right with PD2' values of 4.60 and 4.13, respectively. In addition, DSPM-Cl was found to prolong the duration of action potential 90 (APD90) and effective refractory period (ERP), and decrease the maximal upstroke velocity (Vmax) in K(+)-depolarized guinea pigs papillary muscles. The results suggest that, like verpamil, DSPM-Cl might be a calcium antagonist.

Effect of schisanhenol on function and surface shape of rat neutrophils

AIM

To study the regulatory effect of Schisanhenol (Sal) on function of rat neutrophils.

RESULTS

It was found that Sal (1, 10, and 100 mumol.L(-1)) inhibited neutrophil activities such as chemotaxis, phagocytosis, and superoxide anion production in vitro in a concentration-dependent manner. Changes of surface morphology of neutrophils were observed by scanning electron microscopy, showing that the ruffles and pseudopods on neutrophil surface increased under the stimulation by chemotactic peptide N-formyl-Met-Leu-Phe (FMLP). When pretreated with Sal 100 mumol.L(-1), the ruffles and pseudopods disappeared and the surface became smooth. Sal 100 mumol.L(-1) decreased the cytosolic calcium concentration of neutrophils and increased the intracellular cAMP level.

CONCLUSION

These data suggested that Sal could inhibit the function of rat neutrophils through affecting the cytosolic free calcium and cAMP level besides its anti-oxidant activity.

Effects of nicotinamide on cardiac contraction force and slow inward current

The effects of nicotinamide (Nic) on cardiac contraction force and on slow inward current (Isi) in guinea pigs were studied with atrial strips and voltage clamp techniques. Verapamil (Ver), MnCl2, nifedipine (Nif), and propranolol (Pro) depressed markedly the positive inotropic effect induced by Nic in a noncompetitive manner. The pD2 values of Ver, MnCl2, Nif, and Pro were 6.19, 3.41, 5.00, and 6.43, respectively. The action of Nic was reduced by a low Ca2+ Tyrode solution and disappeared in a Ca(2+)-free solution. Nic 33 mmol.L-1 elevated the Isi from 6.5 +/- 1.3 microA to 10.3 +/- 2.2 microA. The results suggest that Nic promotes the Ca2+ influx and its site of action is different from that of both Pro and the calcium antagonists.

[Cardioprotection of 2-[p-(dimethylamino)styryl]pyridine methiodide against ischemic damage and myocardial lipid peroxidation]

Mice were injected ip DSPM 1 or 3 mg.kg-1 3 h prior to a subcutaneous injection of isoproterenol (Iso) 20 mg.kg-1 once daily for 2 d. Iso induced reductions of Se-glutathione peroxidase (Se-GSH-PX), superoxide dismutase (SOD) activities, and an increase of malondialdehyde (MDA) content in myocardium. DSPM 1 or 3 mg.kg-1 significantly abated reduction of Se-GSH-PX activity and decreased MDA production and DSPM 3 mg.kg-1 also abated reduction of SOD activity in the hearts from Iso-treated mice. The changes of above indices were in accordance with those of myocardial ultrastructure and creatine phosphokinase (CPK) concentration in serum. The results indicate that DSPM has a protective effect on myocardial ischemic injury probably by inhibiting oxygen free radicals and subsequent lipid peroxidation.

Improved myocardial protection by antegrade perfusion in combination with coronary sinus occlusion in the presence of left anterior descending artery obstruction

The present study was undertaken to evaluate the improved protection of antegrade aortic root perfusion combined with intermittent coronary sinus occlusion (APCSO) for the 1-hour ischemic myocardium in the presence of left anterior descending artery occlusion, 12 dogs were divided into 2 groups: anteperfusion (AP) alone (n = 6) and APCSO (n = 6). The experimental results showed that APCSO provided a better cardioplegic distribution and a lower hypothermia (15.6 degrees C versus 17.2 degrees C) in the occluded LAD region, compared with AP. After ischemia, cardiac index and left ventricular stroke index recovered excellently in APCSO (128% to 141% and 115% to 158% of preischemic values, respectively), and much worse in AP (69% to 82% and 53% to 73% of preischemic values, respectively). Our study has confirmed that APCSO is superior to AP in myocardial protection in the presence of coronary artery occlusion.