A systematic review on endoscopic detection rate, endotherapy, and surgery for pancreas divisum

BACKGROUND AND STUDY AIMS

The rates for endoscopic detection of pancreas divisum at routine endoscopic retrograde cholangiopancreatography (ERCP) vary worldwide, and the sample sizes in the reported studies on endoscopy and surgery for pancreas divisum are very small and variable. The aim of this study was to systematically analyze the pooled data and determine endoscopic detection rates for pancreas divisum and pain relief rates in patients with pancreas divisum after endotherapy or surgery.

MATERIALS AND METHODS

A search for published data was performed by using the Medline database (1950 to 1st May 2008) with "pancreas divisum" as the keyword. Publications, mainly on endoscopic detection rate, endotherapy, or surgery for pancreas divisum, were deemed relevant, and were further fully reviewed and analyzed.

RESULTS

A total of 615 abstracts were retrieved from Medline; 17 articles on endoscopic detection rate, 15 articles on endotherapy, and 13 articles on surgery were included in the review and analysis. The overall endoscopic detection rate for pancreas divisum was 2.9% (899/31,413), with the rate being significantly higher in the United States (5.8%) and Europe (6.0%) than in Asia (1.5%) (both P < 0.001). The pooled overall response rates (i. e. complete and partial pain relief rates after treatment) to endotherapy (69.4%, 361/520) and surgery (74.9%, 203/271) were similar (P = 0.106). In addition, there were significant differences in the combined response rates (for endotherapy and for surgery) between patients with pancreas divisum of acute recurrent pancreatitis (ARP)-type (81.2 %) compared with chronic pancreatitis-type (68.8%), and between ARP-type and pain-type (53.1%) (both P < 0.05).

CONCLUSIONS

The endoscopic detection rate for pancreas divisum is much higher in western countries than in Asian countries. The pooled response rates of patients with pancreas divisum to endotherapy and surgery are similar in the reported series. Patients with ARP-type pancreas divisum respond better to endotherapy or surgery than those with chronic pancreatitis-type and pain-type.

Prospective observational study of acute coronary syndromes in China: practice patterns and outcomes

OBJECTIVE

To describe the investigation and management of patients admitted to hospitals in China with suspected acute coronary syndromes (ACS) and to identify potential areas for improvement in practice.

DESIGN

A multicentre prospective survey of sociodemographic characteristics, medical history, clinical features, in-hospital investigations, treatment practices and major events among patients with suspected ACS.

SETTING

Large urban public hospitals.

PATIENTS

Consecutive patients admitted to in-patient facilities with a diagnosis of suspected acute myocardial infarction (MI) or unstable angina pectoris.

MAIN OUTCOME MEASURES

Myocardial infarction/re-infarction, heart failure, death.

RESULTS

Between September 2004 and May 2005, data were collected prospectively from 2973 patients admitted to 51 hospitals in 18 provinces of China. An initial diagnosis of ST elevation MI, non-ST elevation MI and unstable angina was made in 43%, 11% and 46% of patients, respectively. Diagnosis was inconsistent with objective measures in up to 20% of cases. At both tertiary and non-tertiary centres, there was little evidence that clinical risk stratification was used to determine the intensity of investigation and management. The mortality rate during hospitalisation was 5% overall and similar in tertiary and non-tertiary centres, but reported in-hospital re-infarction rates (8%) and heart failure rates (16%) were substantially higher at non-tertiary centres.

CONCLUSION

This study has identified a number of areas in the management of ACS patients, including diagnosis and risk stratification, which deviate from current guidelines. These findings will help inform the introduction of widely used quality improvement initiatives such as clinical pathways.

First Report of Spirea Witches'-Broom Disease in China

Bumald spirea (Spiarea bumalda Burv.) is an important ornamental tree widely grown in northern China. In August of 2006, spirea plants exhibiting symptoms of witches'-broom, stunting, yellowing, and shoot dieback were found at an incidence of 5 to 15% in Qingzhou City, Shandong Province, China. Total DNA was extracted separately from 0.1 g of phloem tissue from leaf midribs and stems of six symptomatic and six asymptomatic plants with a modified cetyltriethylammonium bromide (CTAB) method (3). Resulting DNA samples were analyzed for phytoplasma DNA by a nested PCR assay using phytoplasma universal 16S rDNA gene primer pairs R16mF2/R16mR1 and R16F2n/R16R2 (2). These primers amplified 1.5- and 1.2-kb products, respectively, from DNA of all symptomatic plants only. Restriction fragment length polymorphism (RFLP) analysis of the 1.2-kb 16S rDNA product using enzymes AluI, MseI, and HhaI indicated that all symptomatic plants contained a group 16SrI (aster yellows group) subgroup B (16SrI-B) phytoplasma strain (4). A 16S rDNA sequence derived from this strain (GenBank Accession No. EF176608) was most similar (99.8 and 99.6%) to those of severe aster yellows (GenBank Accession No. M86340) and Maryland aster yellows (GenBank Accession No. AF322644) phytoplasmas, respectively, thereby confirming strain identity based on RFLP analysis. A phytoplasma (Spiarea stunt phytoplasma, GenBank Accession No. AF190228), which belongs to X-disease group (16SrIII), was reported to infect spirea and probably be lethal to S. tomentosa in New York (1,4). The phytoplasma reported here shared low identity (90.8%) with Spiarea stunt phytoplasma, but also caused dieback of spirea shoots. The epidemiology and economic impact of this disease need further intensive investigation. To our knowledge, this is the first report of spirea witches'-broom disease and of its association with a subgroup 16SrI-B phytoplasma in China. References: (1) H. M. Griffiths et al. Can. J. Plant Pathol. 16:255, 1994. (2) D. E. Gundersen and I.-M. Lee. Phytopathol. Mediterr. 35:144, 1996. (3) Y. Qi et al. Biotechnol. Bull. 4:44, 2004. (4) The IRPCM Phytoplasma/Spiroplasma Working Team-Phytoplasma Taxonomy Group. Int. J. Syst. Bacteriol. 54:1243, 2004.

Effects of immunosuppressive drugs on in vitro neogenesis of human islets: mycophenolate mofetil inhibits the proliferation of ductal cells

Assuming that neogenesis contributes to long-term function of islet grafts, it is important to study the effects of immunosuppressive drugs on precursor cell proliferation and differentiation. We examined the effects of low-dose immunosuppressive drugs on these processes in vitro. Immunosuppressive drugs, including sirolimus, tacrolimus, mycophenolate mofetil (MMF), daclizumab and their combinations were tested in parallel culture wells through either the expansion phase (5-7 days) or the entire culture period (4-5 weeks). MMF, alone or in combination with sirolimus or tacrolimus, severely hampered duct-cell proliferation by 8-fold during the expansion period, and significantly reduced the total DNA content by about 40% after 5-week culture. After 4-5 week exposure to different drugs, only sirolimus and daclizumab showed no adverse effects on insulin content, whereas significant reductions of 30-60% in insulin content were seen in all other experimental groups. Only tacrolimus decreased the insulin content per DNA, as well as the proportion of insulin-positive cells. In conclusion, MMF has a potent inhibitory effect on neogenesis primarily through an antiproliferative effect on the precursors, whereas tacrolimus mainly affects beta-cell differentiation. Sirolimus and daclizumab have no adverse effects on these parameters. The immunosuppressive protocol may be an important determinant of long-term clinical islet graft function.

Conversion from cyclosporine to mycophenolate mofetil improves expression of A20 in the rat kidney allografts undergoing chronic rejection

AIMS

Cytoprotective genes have shown to display potent anti-inflammatory and antiapoptotic functions in endothelial and smooth muscle cells. We investigated whether cytoprotective genes, especially A20, were involved in mycophenolate mofetil (MMF)'s ability to ameliorate transplant arteriosclerosis in an experimental chronic rejection model.

METHODS

Sprague-Dawley rat renal grafts were orthotopically transplanted into Wistar rats following the procedure of Kamada with our modification. The recipients were divided into three oral treatment groups: (1) vehicle group (cyclosporine [CsA] 10 mg/kg.d x 10 d followed by vehicle), (2) CsA group (CsA 10 mg/kg.d x 10 d followed by CsA 6 mg/kg.d), (3) MMF group (converted from CsA 10 mg/kg.d x 10 d to MMF 20 mg/kg.d on day 11). At the same time points after transplantation, the rats were sacrificed to harvest the renal allografts. The expression of four cytoprotective genes, A20, heme oxygenase (HO)-1, Bcl-2, and Bcl-XL, was analyzed by quantitative reverse-transcriptase polymerase chain reaction and immunohistochemistry.

RESULTS

The four-cytoprotective genes were all detected in rat kidney allografts undergoing chronic allograft nephropathy. The expression of A20 in grafted kidneys was significantly higher in the MMF than in the CsA or the vehicle group (P < .01). There was no significant difference between the CsA and the MMF groups in the expression of HO-1, Bcl-2, and Bcl-XL.

CONCLUSIONS

We demonstrated that MMF improved the expression of A20 in rat kidney allografts undergoing chronic allograft nephropathy. The correlation between MMF and A20 provide an explanation for the mechanism by which MMF ameliorates transplant arteriosclerosis in an experimental animal model of chronic rejection.

The effects of different immunosuppressants on chronic allograft nephropathy by affecting the transforming growth factor-beta and Smads signal pathways

OBJECTIVE

This study investigated the effects of various immunosuppressants on chronic allograft nephropathy (CAN) by affecting transforming growth factor-beta (TGF-beta) and Smads signal pathway.

METHODS

Vascular smooth muscle cells (VMSC) from rat aorta were incubated for 6 or 12 hours with various immunosuppressants. Cyclosporine (CsA) (3 microg/mL), FK506 (1 microg/mL), mycophenolate mofetil (MMF) (0.3 microg/mL), rapamycine (Rapa) (10 microg/mL), CsA (1 microg/mL/MMF 0.3 microg/mL). We used the Sprague-Dawley Wistar rat accelerated kidney sclerosis model. Before transplantation, the kidney was preserved 1 hour in 0 degrees C to 4 degrees C heparin sodium chloride solution to reinforce the cold ischemia injury. The rats were divided into eight groups (each group n = 8): group A, pseudo-OP; group B, isotransplantation; group C, CsA 6 mg/kg . d; group D, FK506 0.15 mg/kg . d; group E, MMF 20 mg/kg . d; group F, Rapa 0.8 mg/kg. d; group G, CsA 3 mg/kg . d + MMF 20 mg/kg . d. The serum creatinine levels and pathological changes, according to the Banff scheme, were observed at 2, 4, 6, 8 and 12 weeks posttransplantation. Immunohistochemistry and quantitative fluorescence polymerase chain reactions were used to end localize and quantitate the expression of TGF-beta1 and Smad 2, 3, 7 in VMSC and in the transplanted kidney.

RESULTS

CsA and FK506 stimulated gene expression and protein production of TGF-beta1, smad2, and smad3, but inhibited expression of smad7 both in VSMC and in the transplanted kidney. In contrast, MMF and Rapa down-regulated gene expression and protein production of TGF-beta1, smad2, 3 while up-regulating expression of smad7. There was no significant difference between the CsA group and the FK506 group, as well as the MMF group and the Rapa group. The group treated with CsA + MMF was similar to the MMF and the Rapa groups.

CONCLUSION

Our study suggested that various immunosuppressants affected differentially TGF-beta1 and Smads signal pathways in rat VSMC and kidney grafts. CsA and FK506 can cause CAN, owing to up-regulated expression of smad2 and smad3, and down-regulation of smad7 expression. MMF and Rapa can prevent the CAN progression, because of down-regulation of the expression of smad2 and smad3, with increased smad7 production.

Expression of fractalkine, CX3CR1, and vascular endothelial growth factor in human chronic renal allograft rejection

AIM

Fractalkine/CX3CR1 system may contribute to the pathogenesis of renal allograft chronic rejection (CR). Vascular endothelial growth factor (VEGF) is an endothelial mitogen, which shows increased expression in inflammation and vasculopathy. This study sought describe the expression and distribution of Fractalkine/CX3CR1 and VEGF, and their relationship to human renal allograft CR.

METHODS

Renal tissue from 10 patients with CR was examined for Fractalkine/CX3CR1 and VEGF protein by immunohistochemistry for comparison with patients displaying hyperacute rejection (n = 10), acute rejection (n = 10), and normal kidneys (n = 10). All patients were selected based upon histologically proven diagnoses between 1992 and 2003.

RESULTS

Immunohistochemistry revealed that Fractalkine/CX3CR1 were mostly expressed in the tubulointerstitium and tubular epithelial cell basolateral membrane. Some vessels showed positive staining for Fractalkine/CX3CR1 as well as occasionally glomerular parietal wall cells. Among the CR group, VEGF was mostly expressed in tubular epithelium and the tubulointerstitium. A proportion of glomeruli and vessels had positive staining for VEGF, which was up-regulated most strikingly in the interstitial compartment in CR. There was markedly increased expression of Fractalkine/CX3CR1 and VEGF protein in the interstitium of the CR compared with other groups (P < .05). VEGF colocalized with the expression of Fractalkine/CX3CR1.

CONCLUSION

Fractalkine/CX3CR1 and VEGF may play an important role in the development of interstitial fibrosis via mononuclear cell-induced cytokine production and myofibroblast stimulation in CR. Further studies are necessary to identify the role in the pathogenesis of CR.

Comparison of cyclosporine versus mycophenolate mofetil on expression of Fractalkine and CX3CR1 in chronic allograft nephropathy

INTRODUCTION

We sought to investigate whether there was a difference between cyclosporine (CsA) and mycophenolate mofetil (MMF) to affect the expression of Fractalkine/CX3CR1 in chronic allograft nephropathy (CAN).

METHODS

The Sprague-Dawley Wistar rat accelerated kidney sclerosis model was performed as modified from the procedure of Kamada. Recipients were divided into three oral treatment groups (each group n = 8): group A was CsA 10 mg/kg . d for 10 days followed by vehicle; group B was CsA 10 mg/kg . d for 10 days followed by CsA 6 mg/kg.d; group C was CsA 10 mg/kg . d for 10 days followed by MMF 20 mg/kg . d. Pathological changes graded according to Banff 97 Standards were observed at 4, 8, and 12 weeks posttransplantation. The immunohistochemistry and quantitative real-time fluorescence polymerase chain reaction (PCR) were used to assess the distribution and expression of Fractalkine/CX3CR1 in the grafted kidney.

RESULTS

Fractalkine/CX3CR1 were mostly expressed in the tubulointerstitium and tubular epithelial cell basolateral membrane. A proportion of the vessel showed positive staining for Fractalkine/CX3CR1, occasionally in glomerular parietal wall cells. The expression of Fractalkine/CX3CR1 in grafted kidneys at all the time points was significantly less in the MMF than in the CsA group or the control group (P < .05). Real-time fluorescence quantitative PCR revealed similar outcomes as immunohistochemistry. The expression of Fractalkine coincided with CX3CR1.

CONCLUSION

Fractalkine/CX3CR1 may play an important role in the development of interstitial fibrosis in CAN. Different immunosuppressants have various effects on expression of the Fractalkine/CX3CR1.

Comparison of rapamycin versus FK506 on expression of cytoprotective genes in the rat kidney allografts undergoing chronic allograft nephropathy

AIMS

It is increasingly recognized that expression of cytoprotective genes in grafts can affect the progress of chronic allograft nephropathy (CAN). Little is known about the influence of different immunosuppressive regimens on expression of cytoprotective genes in allografts undergoing CAN. We investigate whether there is difference between rapamycin (Rapa) and FK506 in the expression of cytoprotective genes in rat kidney allografts undergoing CAN.

METHODS

Sprague-Dawley rat renal grafts were orthotopically transplanted into Wistar rats following the procedure of Kamada with our modification. The recipients were divided into three oral treatment groups: group 1: vehicle group (cyclosporine [CsA] 10 mg/kg.dx 10 days followed by vehicle); group 2: Rapa group (CsA 10 mg/kg.d x 10 d followed by Rapa 0.8 mg/kg.d); group 3: FK506 group (CsA 10 mg/kg.d x 10 d followed by FK506 0.15 mg/kg.d). At the same times after transplantation, the rats were sacrificed to harvest the renal allografts. The expression of four cytoprotective genes, A20, heme oxygenase (HO)-1, Bcl-2, and Bcl-X/L were analyzed in these grafted kidneys by quantitative reverse transcriptase polymerase chain reaction and immunohistochemistry.

RESULTS

Four cytoprotective genes were all detected in rat kidney allografts undergoing CAN. The expression of A20 in the Rapa group was significantly higher than that in the FK506 or the vehicle group (P < .05). There was no significant difference between the Rapa group and FK506 group in the expressions of HO-1, Bcl-2, and Bcl-X/L.

CONCLUSIONS

We demonstrate that various immunosuppressive agents have different effects on the expression of cytoprotective genes.

The role of ataxin 10 in the pathogenesis of spinocerebellar ataxia type 10

BACKGROUND

Spinocerebellar ataxia type 10 (SCA10) is an autosomal dominant disorder characterized by cerebellar ataxia and seizures. SCA10 is caused by an expansion of an ATTCT pentanucleotide repeat in intron 9 of the ataxin 10 (ATXN10) gene encoding an approximately 55-kd protein of unknown function. However, how this mutation leads to SCA10 is unknown.

METHODS

In an effort to understand the pathogenic mechanism of SCA10, the authors conducted a series of experiments to address the effect of repeat expansion on the transcription and RNA processing of the ATXN10 gene. In addition, we generated Sca10 (mouse ataxin 10 homolog)-null mice and addressed the role of Sca10 gene dosage on the cerebellum.

RESULTS

Mutant ATXN10 allele is transcribed at the normal level, and the pre-mRNA containing an expanded repeat is processed normally in patient-derived cells. Sca10-null mice exhibited embryonic lethality. Heterozygous mutants were overtly normal and did not develop SCA10 phenotype

CONCLUSION

A simple gain of function or loss of function of ATXN10 is unlikely to be the major pathogenic mechanism contributing to the spinocerebellar ataxia type 10 phenotype.

A novel integrin alpha5beta1 binding domain in module 4 of connective tissue growth factor (CCN2/CTGF) promotes adhesion and migration of activated pancreatic stellate cells

BACKGROUND

Connective tissue growth factor (CCN2) is upregulated in pancreatic fibrosis and desmoplastic pancreatic tumours. CCN2 interacts with integrin alpha5beta1 on pancreatic stellate cells (PSC) in which it stimulates fibrogenesis, adhesion, migration, and proliferation.

AIM

To determine the structural domain(s) in CCN2 that interact with integrin alpha5beta1 to regulation PSC functions.

METHODS

Primary activated rat PSC were tested for their adherence to isoforms of CCN2 comprising modules 1-4 (CCN2(1-4)), modules 3-4 (CCN2(3-4)), module 3 alone (CCN2(3)), or module 4 alone (CCN2(4)). Adhesion studies were performed in the presence of EDTA, divalent cations, anti-integrin alpha5beta1 antibodies, CCN2 synthetic peptides, or heparin, or after pretreatment of the cells with heparinase, chondroitinase, or sodium chlorate. CCN2 integrin alpha5beta1 binding was analysed in cell free systems. The ability of CCN2(1-4), CCN2(3-4), or CCN2(4) to stimulate PSC migration was evaluated in the presence of anti-integrin alpha5beta1 or heparin.

RESULTS

PSC adhesion was stimulated by CCN2(1-4), CCN2(3-4), or CCN2(4) and supported by Mg2+ but not Ca2+. CCN2(4) supported PSC adhesion or migration were blocked by anti-integrin alpha5beta1 antibodies or by treatment of cells with heparinase or sodium chlorate. A direct interaction between CCN2(4) and integrin alpha5beta1 was demonstrated in cell free assays. The sequence GVCTDGR in module 4 mediated the binding between CCN2(4) and integrin alpha5beta1 as well as CCN2(4) mediated PSC adhesion and migration.

CONCLUSIONS

A GVCTDGR sequence in module 4 of CCN2 is a novel integrin alpha5beta1 binding site that is essential for CCN2 stimulated functions in PSC and which represents a new therapeutic target in PSC mediated fibrogenesis.

Clinical phenotype of Brazilian families with spinocerebellar ataxia 10

Spinocerebellar ataxia type 10 (SCA10) is an autosomal dominant ataxia caused by an ATTCT repeat expansion in an intron of the SCA10 gene. SCA10 has been reported only in Mexican families, in which the disease showed a combination of cerebellar ataxia and epilepsy. The authors report 28 SCA10 patients from five new Brazilian families. All 28 patients showed cerebellar ataxia without epilepsy, suggesting that the phenotypic expression of the SCA10 mutation differs between Brazilian and Mexican families.

In vitro neogenesis of human islets reflects the plasticity of differentiated human pancreatic cells

AIMS/HYPOTHESIS

The neogenesis of islets from cultured human adult pancreatic tissue has been reported. The islet progenitors have been thought to be ductal cells. Since previous experiments have been 'contaminated' by a number of pre-existing islet cells, we examined their involvement in islet cell neogenesis.

METHODS

Fresh human pancreatic cells with different purities of islet cells were grown in monolayer culture and labelled with bromodeoxyuridine. Transitional cells were analysed by double immunofluorescence staining. For purified ductal cell culture, pre-existing islets were eliminated on a magnetic cell separation system.

RESULTS

We confirmed that less than 1% of the endocrine cells proliferated, mainly during the first 48 h of culture. However, a 10-fold larger proportion of the cells acquired a transitional phenotype by starting to coexpress the ductal marker cytokeratin 19 (CK19). These cells represented more than 10% of all endocrine cells after 1 day in culture, and 6% at 5 days of culture. Using magnetic cell sorting, we eliminated cells expressing neural cell adhesion molecule (N-CAM), after which we obtained 99.7% pure non-endocrine CK19-rich cell populations. These cell populations could be expanded in vitro. However, their endocrine differentiation capacity was severely reduced as compared with the original mixed cell cultures.

CONCLUSIONS/INTERPRETATION

These results suggest that islet neogenesis in this culture system at least partly represents the de-differentiation of islet cells into a duct-cell-like phenotype, with further re-differentiation in appropriate conditions. The plasticity of differentiated human pancreatic cell types may thus be an important mechanism of human pancreas regeneration.

Determination of gene organization in the human IGHV region on single chromosomes

Organization of the IGHV genes (n=108) on single human chromosomes has been determined by detecting these sequences in single sperm using multiplex PCR amplification followed by microarray detection. A total of 374 single sperm samples from five Caucasian males were studied. Three deletion/insertion polymorphisms (Del I-Del III) with deletion allele frequencies ranging from 0.1 to 0.3 were identified. Del I is a previously reported polymorphism affecting three IGHV genes (IGHV1-8, IGHV3-9, and IGHV2-10). Del II affects a region 2-18 kb containing two pseudogenes IGHV(II)-28.1 and IGHV3-29, and Del III spans approximately 21-53 kb involving genes IGHV4-39, IGHV7-40, IGHV(II)-40-1, and IGHV3-41. Deletion alleles of both Dels II and III were found in a heterozygous state, and therefore, could not be easily detected if haploid samples were not used in the study. Results of the present study indicate that deletions/insertions together with other possible chromosomal rearrangements may play an important role in forming the genetic structure of the IGHV region, and may significantly contribute to antibody diversity. Since these three polymorphisms are located within or next to the 3' half of the IGHV region, they may have an important role in the expressed IGHV gene repertoire during immune response.

A comparison of initial treatment with losartan/HCTZ versus losartan monotherapy in chinese patients with mild to moderate essential hypertension

The antihypertensive efficacy and tolerability of losartan/hydrochlorothiazide (HCTZ) and losartan monotherapy as initial treatment were compared in a double-blind trial in Chinese patients with mild to moderate essential hypertension. Patients were randomised to initial treatment with either losartan/HCTZ (50 mg/12.5 mg) or losartan alone (50 mg). The doses were doubled after four weeks if diastolic blood pressure (SiDBP)was >90 mmHg. Both losartan/HCTZ and losartan alone significantly reduced SiDBP and SiSBP from baseline at the first measurement at 4 weeks (-10.1/-15.3 and -6.1/-6.9 mmHg, respectively; p<0.001) and at 8 weeks (-13.1/-18.5 and -8.7/-10.9 mmHg; p<0.001). The reductions with losartan/HCTZ were significantly greater than with losartan alone at weeks 4 and 8 (p<0.001). Both regimens were similarly well tolerated. In conclusion, initial therapy with losartan/HCTZ is effective and well tolerated in the treatment of Chinese patients with mild to moderate essential hypertension and produces a greater reduction in blood pressure than losartan alone.

Pharmacological characterization of mikatoxin, an alpha-neurotoxin isolated from the venom of the New-Guinean small-eyed snake Micropechis ikaheka

Symptoms of envenomation by the New-Guinean small-eyed snake Micropechis ikaheka (Elapidae) include peripheral neurotoxicity and myotoxicity. We have now purified to homogeneity a long-chain neurotoxin, mikatoxin, from M. ikaheka venom by successive gel filtration and reverse-phase chromatography. Electrospray ionization mass spectrometry showed mikatoxin to be a homogenous peptide of MW 7775.6. Mikatoxin was devoid of any phospholipase A(2) activity associated with the crude venom and did not exhibit any intrinsic anticholinesterase activity. In the chick biventer cervicis muscle, it produced an irreversible, concentration-dependent block of responses to exogenously applied acetylcholine and carbachol as well as twitches evoked by nerve, but not by direct muscle stimulation. Moreover, mikatoxin, like alpha-bungarotoxin and erabutoxin-b, did not show significant fade response to train-of-four stimulation of the mouse phrenic nerve-hemi diaphragm muscle. It also failed to block ganglionic transmission in the guinea pig ileum and muscarinic responses in the rat anococcygeus muscle. Our study provides strong evidence for the presence of a neurotoxin (mikatoxin) in M. ikaheka venom that produces neuromuscular blockade in skeletal muscle attributable to selective and irreversible antagonism of postsynaptic nicotinic acetylcholine receptors of the neuromuscular junction and likely contributes to the peripheral neurotoxicity observed in M. ikaheka envenomation.

[Comparative effects of carvedilol, losartan and their combination in preventing left ventricular remodeling after acute myocardial infarction in rats]

OBJECTIVE

To compare the effects of carvedilol, losartan and their combination in preventing from left ventricular remodeling (LVRM) after acute myocardial infarction(AMI) in rats.

METHODS

Twenty-four hours after ligating left coronary artery, 100 surviving AMI female SD rats were randomly assigned to: (1) AMI control (n = 25), (2) carvedilol (1 mg x kg(-1) x d(-1)) (C1) (n = 25); (3) losartan (3 mg x kg(-1) x d(-1)) (L3)(n = 25); and (4) carvedilol (1 mg x kg(-1) x d(-1)) + losartan (3 mg x kg(-1) x d(-1)) (C1 + L3) (n = 25) groups. Sham-operated group (n = 17) were selected randomly as non-infarction control. After 4 weeks of therapy with the drugs by gastric gavage, hemodynamic studies were performed, then the rat hearts were fixed and pathologically analyzed. Exclusive of the rats with MI size < 35% or > 55%, complete data were obtained in 65 rats, which were comprised of AMI control (n = 13), C1 (n = 12), L3 (n = 13), C1 + L3 (n = 14) and sham-operated (n = 13) groups.

RESULTS

There were no significant differences in MI size among the four AMI groups (45.8% - 46.7%, P > 0.05) . Compared with sham-operated group, Left ventricular (LV) end diastolic pressure (LVEDP), volume (LVV), weight (LVW), septal thickness (STh) and right ventricular weight (RVW) were all significantly increased (all P < 0.01 ) in AMI group, while the left ventricular pressure maximal rate of rise and fall (dp/dt) were significantly decreased (all P < 0.01). In comparison with AMI group, LVEDP, LVV, LVW, STh and RVW were all significantly decreased (all P < 0.01), while +/- dp/dt and +/- dp/dt/LVSP were significantly increased (P < 0.05 - 0.01) in all three therapy groups, with LVEDP decreasing more in the combination and L3 groups than in C1 group (P < 0.05 - 0.01) and STh decreasing more in the combination group than in C1 group (P < 0.01), but there were no significant differences in other variables among the three therapy groups.

CONCLUSION

Carvedilol, losartan and their combination all can prevent from LVRM after AMI in rats, improve hemodynamics and LV function, with the combination superior.

Reaction of arylphosphines with singlet oxygen: intra- vs intermolecular oxidation

[reaction--see text] The chemistry of singlet oxygen with all three isomers of tris(methoxyphenyl)phosphine has been studied. For the severely hindered ortho isomer, intramolecular rearrangement to form phenyl diphenyl phosphinate is preferred to formation of phosphine oxide at low concentration in aprotic solvents. In protic solvents, no intramolecular reactivity is observed. A detailed kinetic analyses has been undertaken. There is no physical quenching, regardless of solvent. Mechanistic implications of these findings are discussed.

[Glaucoma seton implantation surgery via different pathways for complicated glaucoma]

OBJECTIVE

To evaluate the effectiveness of glaucoma seton implantation surgeries via three different pathways for complicated glaucoma.

METHODS

Ninety-nine cases (99 eyes) with complicated glaucoma having undergone glaucoma seton implantation surgeries were divided into three groups. Fifty-eight cases were included (58 eyes) in the group with anterior chamber implantation (AC group), 16 cases (16 eyes) were in the group with posterior chamber implantation (PC group) and 25 cases (25 eyes) were in the group with vitreous cavity implantation (VC group).

RESULTS

The follow-up ranged from 6 to 34 months (mean 19.6 months). In the AC group, the postoperative intraocular pressure (IOP) of 40 cases (69.0%) was < 21 mm Hg (1 mm Hg = 0.133 kPa) without using any pressure-lowering agents. The postoperative IOP of 6 cases (10.3%) was < 21 mm Hg with pressure-lowering agents. Patients with IOP controlled < 21 mm Hg were altogether 46 cases (79.3%). The IOP of 11 cases (68.8%) in the PC group was controlled without agents and another 1 case (6.2%) was controlled with medications. Therefore, the total success rate was 75.0% (12 cases). The corresponding rates for the VC group were 10 cases (40.0%), 3 cases (12.0%) and 13 cases (52.0%) respectively. Statistical significant difference (chi 2 = 6.525, P = 0.038) was found in the success rates among these 3 groups. But if we excluded cases with neovascular glaucoma, no statistical difference (chi 2 = 4.231, P = 0.121) was found of the success rates among these 3 groups.

CONCLUSION

No influence on surgical effectiveness was found among glaucoma seton implantation surgeries via different pathways for complicated glaucoma.