Preservation of the ischaemic canine kidney with inosine

Summary Direct intra-renal perfusion of inosine was found to protect the canine kidney from 90 min of warm is chaemia.Significantly lower (P<0.01) serum creatinine levels were found 24 and 72 h post-operatively in an inosine treated group (N=12) when compared to a control group (N=5).Histological examination of the pre-treated kidneys confirmed the protective effect of inosine.     

The receptor mechanism mediating the contractile response to adenosine on lung parenchymal strips from actively sensitised,allergen-challenged Brown Norway rats

Parenchymal strips prepared from lungs removed from actively sensitised Brown Norway rats challenged with allergen show hyperresponsiveness to adenosine. The response is mast cell mediated and a preliminary pharmacological analysis suggested the involvement of a receptor (or receptors) that could not be classified as any of the known adenosine receptor subtypes. We present a further analysis of the response. Male Brown Norway (BN) rats, actively sensitised to ovalbumin (OA), were challenged intratracheally with OA and killed 3 h later to provide parenchymal strip preparations. The augmented contractile responses to adenosine were partially blocked by the 5-HT receptor antagonist, methysergide, or the A₁ receptor antagonist, DPCPX, and abolished in the presence of both antagonists. Responses to high concentrations of the A₁ receptor agonist, CPA were, like those to adenosine, augmented on tissues from allergen-challenged animals and blocked by a combination of methysergide and DPCPX. The A₃ receptor agonist, Cl-IB-MECA, did not contract the tissue, but partially blocked the response to adenosine. A combination of Cl-IB-MECA and methysergide induced a similar degree of blockade to that seen with either drug given alone. Combination of Cl-IB-MECA and/or methysergide with DPCPX abolished the response to adenosine. The effects of the A₃ receptor agonist, inosine, were augmented on tissues from allergen-challenged animals and markedly inhibited by disodium cromoglycate, methysergide or Cl-IB-MECA. Responses to adenosine were abolished when parenchymal strips were taken from rats pretreated 48 h previously with pertussis toxin. 8-SPT, CGS 15943, XAC, MRS 1754, DPCPX and theophylline, at concentrations which inhibit the A₁ A_2A and/or A_2B receptors but have negligible affinity for the rat A₃ receptor, inhibited responses to adenosine, but high concentrations were required and blockade was incomplete. MRS 1523 and MRS 1191, which are antagonists at the rat A₃ receptor, had no effect on the response to adenosine. The present results support and clarify our earlier conclusion that an atypical receptor mechanism mediates contraction of the parenchymal strip prepared from the lungs of actively sensitised BN rats challenged with allergen to adenosine. The response arises from a combined effect of adenosine on the A₁ receptor and a receptor with similarities to the A₃ receptor, but where Cl-IB-MECA behaves as an antagonist and MRS 1523 and MRS 1191 are inactive at concentrations that substantially exceed their affinities for the rat A₃ receptor.A part of this work was presented to the British Pharmacological Society in January 2003     

Differences between rat primary cortical neurons and astrocytes in purine release evoked by ischemic conditions

In the brain, the levels of adenosine increase up to 100-fold during cerebral ischernia; however, the roles of specific cell types, enzymatic pathways and membrane transport processes in regulating intra- and extracellular concentrations of adenosine are poorly characterized. Rat primary cortical neurons and astrocytes were incubated with [(3)H]adenine for 30 min to radiolabel intracellular ATP. Cells were then treated with buffer, glucose deprivation (GD), oxygen-glucose deprivation (OGD), 100 micro M sodium cyanide (NaCN) or 500 micro M iodoacetate (IAA) for 1 h to stimulate the metabolism of ATP and cellular release of [(3)H]purines. The nucleoside transport inhibitor dipyridamole (DPR) (10 micro M), the adenosine kinase inhibitor iodotubercidin (ITU) (1 micro M), the adenosine deaminase inhibitor EHNA (1 micro M) and the purine nucleoside phosphorylase inhibitor BCX-34 (10 micro M) were tested to investigate the contribution of specific enzymes and transporters in the metabolism and release of purines from each cell type. Our results indicate that (a). under basal conditions astrocytes released significantly more [(3)H]adenine nucleotides and [(3)H]adenosine than neurons, (b). OGD, NaCN and IAA conditions produced significant increases in [(3)H]adenosine release from neurons but not astrocytes, and (c) DPR blocked [(3)H]inosine release from both astrocytes and neurons but only blocked [(3)H]adenosine release from neurons. These data suggest that, in these experimental conditions, adenosine was formed by an intracellular pathway in neurons and then released via a nucleoside transporter. In contrast, adenine nucleotide release and extracellular metabolism to adenosine appeared to predominate in astrocytes.     

Distribution of ITPA P32T alleles in multiple world populations

Dose-limiting toxicity from azathioprine treatment affects up to 37% of patients. Screening for thiopurine methyltransferase (TPMT) polymorphisms will prospectively identify approximately 10% of patients. Recently, a polymorphism in the inosine triphosphate pyrophosphatase gene (ITPA) has been associated with severe azathioprine toxicity. We demonstrate here that this proline to threonine substitution at codon 32 in the ITPA gene is found at low frequency in Central/South American populations (1–2%), at a constant frequency across Caucasian and African populations (6–7%), and is highest in Asian populations (14–19%). This data is consistent with previously described allele frequencies in other Caucasian (7%), African (5%), and Asian (11–15%) populations. This data provides a foundation on which prospective screening studies can be planned to identify patients at risk for severe toxicity from azathioprine therapy.     

Case report of a rare purine synthesis disorder due to 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase (AICAR) deficiency

BackgroundAICA (5-aminoimidazole-4-carboxamide) ribosiduria is an inborn error in purine biosynthesis caused due to biallelic pathogenic variants in the 5-aminoimidazole-4-carboxamide ribonucleotide-formyltransferase/imp cyclohydrolase (ATIC) gene located on chromosome 2q35. ATIC codes for a bifunctional enzyme, AICAR transformylase and inosine monophosphate (IMP) cyclohydrolase, which catalyse the last two steps of de novo purine synthesis. This disorder has been previously reported in only 4 cases worldwide, and herein, we report the first from India.Case ReportThe proband presented with global developmental delay, developmental hip dysplasia (DDH), acyanotic heart disease and nystagmoid eye movements. Whole exome sequencing (WES) identified compound heterozygous pathogenic variants in the ATIC. A novel splice site variant; c.1321-2A > G and a previously reported missense variant; c.1277A > G (p.Lys426Arg) were identified. Segregation analysis of parents showed the father to be a heterozygous carrier for the splice site variant and the mother, a heterozygous carrier for the missense variant.ConclusionThis case of a rare genetic disorder of purine biosynthesis of ATIC deficiency is the first case reported from India. Early diagnosis lead to early interventional therapy and genetic counselling.     

复合磷酸酯酶肠溶片联合水飞蓟宾胶囊治疗70例单纯酒精性肝病的临床观察

目的 探讨复合磷酸酯酶肠溶片联合水飞蓟宾胶囊治疗单纯酒精性肝病的临床疗效.方法 选取70例单纯酒精性肝病随机分成两组,对照组采用肌苷片联合水飞蓟宾胶囊,治疗组在对照组基础上加用复合磷酸酯酶肠溶片,观察两组患者的ALT/AST/TBIL/GGT以及临床症状的改善情况.结果 复合磷酸酯酶肠溶片联合水飞蓟宾胶囊能有效的降低转氨酶,改善症状总有效率为100%,对照组总有效率为57.14%,治疗组临床总有效率明显高于对照组(P<0.05).结论 复合磷酸酯酶肠溶片联合水飞蓟宾胶囊临床治疗效果良好,值得应用.     

软坚散结方治疗早期肝硬变临床研究

目的:观察软坚散结方治疗早期肝硬变的临床疗效。方法:选取早期肝硬变患者84例,随机分为观察组与对照组各42例,对照组给予西药常规治疗,观察组给予中药软坚散结方治疗,观察两组患者临床疗效。结果:对照组有效率为66.67%,观察组有效率为92.86%,观察组有效率显著高于对照组,比较有统计学意义(P0.05);观察组治疗后的ALT、AST、TBil指标水平均显著高于对照组,且Alb、A/G水平显著低于对照组,比较有统计学意义(P0.05);观察组治疗后的HA、LN、PCⅢ、Ⅳ-C及TGF-β1水平显著低于对照组,有统计学意义(P0.05)。结论:软坚散结方治疗早期肝硬变能有效阻止疾病进展及改善患者肝功能,疗效显著。     

病毒唑的合成新工艺

目的：采用合成新工艺提高病毒唑的收率。方法：用肌苷为原料,经乙酰化后在双磷酸酯的作用下与1,2,4-三氮唑-3-羧酸甲酯缩合,再经氨解制得产品。结果：以肌苷计,总收率为48％。结论：该合成路线简单实用,易在生产中推广。     

HPLC同步测定肌酸,磷酸肌酸,腺苷酸及次黄嘌呤类物质

本文用反相HPLC法,以TBA(四丁基氢氧化铵)作离子对试剂,用含13％甲醇的磷酸钾缓冲液进行等比洗脱,同步分离测定了肌酸(Cr)、磷酸肌酸(Crp)、次黄嘌呤(HX)、次黄嘌呤核苷(INO)及AMP、ADP、ATP七种标准品的混合物。结果表明,在210nm波长下,10分钟内上述七种物质均完全分开且基线未漂移,重现性好,是一种简便、快速和可靠的方法。