Role of ATP and related purines in inhibitory neurotransmission to the pig urinary bladder neck

Background and purpose:

As adenosine 5′-triphosphate (ATP) is one of the inhibitory mediators of the bladder outflow region, this study investigates the possible release of ATP or related purines in response to electrical field stimulation (EFS) and the purinoceptor(s) involved in nerve-mediated relaxations of the pig urinary bladder neck.

Experimental approach:

Urothelium-denuded and intact phenylephrine-precontracted strips were mounted in organ baths containing physiological saline solution at 37°C and gassed with 95% O₂ and 5% CO₂ for isometric force recordings.

Key results:

EFS, in the presence of atropine, guanethidine and N^G-nitro-L-arginine, and exogenous purines, produced frequency- and concentration-dependent relaxations respectively. Adenosine 5′-diphosphate (ADP) and adenosine were more potent than ATP in producing relaxation, while uridine 5′-triphosphate, uridine 5′-diphosphate and α,β-methylene ATP were less effective. The non-selective P2 antagonist suramin, and the P2Y₁ and P1 receptor blockers 2′-deoxy-N6-methyladenosine 3′,5′-bisphosphate tetrasodium and 8-(p-sulphophenyl)theophylline, respectively, inhibited the responses to EFS and ATP. The P1 agonist''s potency was: 5′-N-ethylcarboxamidoadenosine (NECA)>4-2[[6-amino-9-(N-ethyl-b-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzene propanoic acid hydrochloride>2-chloro-N⁶-cyclopentyladenosine>-2-chloro-6-[[(3-iodophenyl)methyl]amino]-9H-purin-9-yl]-1-deoxy-N-methyl-b-D-ribofuranuronamide = adenosine. 4-(-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl) phenol, an A_2A antagonist, reduced the relaxations to EFS, adenosine and NECA. In urothelium-intact samples, relaxations to EFS and purines were smaller than in urothelium-denuded preparations. Neuronal voltage-gated Na⁺ channels blockade failed to modify ATP relaxations. At basal tension, EFS- and ATP-induced contractions were resistant to desensitization or blockade of P2X₁ and P2X₃ receptors.

Conclusions and implications:

ATP is involved in the non-adrenergic, non-cholinergic, non-nitrergic inhibitory neurotransmission in the pig bladder neck, producing relaxation largely through muscle A_2A receptors after breakdown to adenosine, and P2Y₁ receptors after breakdown to ADP. Antagonists of these receptors may be useful for urinary incontinence treatment produced by intrinsic sphincteric deficiency.     

维A类化合物4-APR抑制肿瘤侵袭、转移的作用

用体内外实验模型,研究了新维A类化合物4-乙酰胺苯基维A酸酯(4-APR)对肿瘤侵袭、转移的抑制作用。4-APR 43.3mg·kg^-1po即能减少小鼠Lewis肺癌的自发性肺转移瘤数。半体内实验证明4-APR10^-5mol·L^-1和10^-6mol·L^-1对B16-F10癌细胞的人工肺转移瘤数分别抑制67.9%和36.6%。体外实验显示,4-APR对B16-F10细胞侵袭重组基底膜的抑制率分别为54.2%和41.9%。     

Direct identification of Yersinia enterocolitica in blood by polymerase chain reaction amplification

Primers based on the nucleotide sequence of the virF gene in the pYV plasmid and the chromosomal ail gene were used in polymerase chain reaction (PCR) amplifications to directly identify Yersinia enterocolitica in blood. Approximately 500 bacteria seeded into 100 microL of blood can be extracted and amplified by PCR to yield positive results. PCR analyses of seven Y. enterocolitica isolates previously implicated in blood contaminations showed that only one isolate harbored the plasmid-borne virF gene; however, all seven isolates were identified effectively by the PCR product amplified from the chromosomal gene. The PCR assay has the potential for use in the identification of Y. enterocolitica contamination in stored units of blood or in the rapid diagnosis of transfusion-related bacteremia caused by Y.     

1,3,8-Triazaspiro[4.5]decane-2,4-diones as efficacious pan-inhibitors of hypoxia-inducible factor prolyl hydroxylase 1-3 (HIF PHD1-3) for the treatment of anemia

The discovery of 1,3,8-triazaspiro[4.5]decane-2,4-diones (spirohydantoins) as a structural class of pan-inhibitors of the prolyl hydroxylase (PHD) family of enzymes for the treatment of anemia is described. The initial hit class, spirooxindoles, was identified through affinity selection mass spectrometry (AS-MS) and optimized for PHD2 inhibition and optimal PK/PD profile (short-acting PHDi inhibitors). 1,3,8-Triazaspiro[4.5]decane-2,4-diones (spirohydantoins) were optimized as an advanced lead class derived from the original spiroindole hit. A new set of general conditions for C-N coupling, developed using a high-throughput experimentation (HTE) technique, enabled a full SAR analysis of the spirohydantoins. This rapid and directed SAR exploration has resulted in the first reported examples of hydantoin derivatives with good PK in preclinical species. Potassium channel off-target activity (hERG) was successfully eliminated through the systematic introduction of acidic functionality to the molecular structure. Undesired upregulation of alanine aminotransferese (ALT) liver enzymes was mitigated and a robust on-/off-target margin was achieved. Spirohydantoins represent a class of highly efficacious, short-acting PHD1-3 inhibitors causing a robust erythropoietin (EPO) upregulation in vivo in multiple preclinical species. This profile deems spirohydantoins as attractive short-acting PHDi inhibitors with the potential for treatment of anemia.     

Retroperitoneal sarcomas: A review of disease spectrum,radiological features,characterisation and management

Retroperitoneal sarcomas are a rare disease. The overall 5‐year survival rate for these lesions remains low, and surgical management offers the only option for effective treatment and potential for cure. Radiotherapy is increasingly being employed in addition to standard surgical treatment. Improvements in cross‐sectional imaging have also facilitated better characterisation of lesions, preoperative planning and long‐term follow‐up. This article reviews the current literature and documents the various types of retroperitoneal sarcomas with a particular approach to their imaging features. We also highlight the pathology, diagnostic methods and most current management of these tumours.     

Joining the dots: a plea for precise estimates of the maternal mortality ratio in sub-Saharan Africa

Monitoring of maternal mortality levels in sub-Saharan Africa (SSA) to assess the achievements of safe motherhood programmes and for MDG-5 has been made difficult because of the lack of precise estimates of the maternal mortality ratio (MMR). Projections based on the slow rate of decline of the MMR indicate that MDG-5 may not be reached before the end of this century in this region. Measurements done using demographical and health surveys, statistical modelling and censuses are imprecise and do not allow trends in individual countries to be established. SSA countries should be encouraged to measure mortality levels from their own resources, using methods that produce precise estimates such as population-based surveys. Establishment of the trends will lead to country-specific program targets. The less frequent but more precise measurements can be afforded by SSA countries, as a case study from Zimbabwe shows.     

Development of hatching blastocysts from immature human oocytes following in-vitro maturation and fertilization using a co-culture system

Recently, in-vitro maturation (IVM) of immature human oocytes recovered from non-stimulated follicles has been applied in the treatment of infertility. However, in previous reports, very few embryos cultured in conventional medium have reached the expanded blastocyst stage following in-vitro maturation and fertilization (IVM/IVF). The objective of this study was to investigate whether the developmental competence of human embryos following IVM/IVF could be enhanced by the use of a human ampullary cell co-culture system. Immature human oocytes were aspirated from small follicles at Caesarean section and then cultured in medium containing human menopausal gonadotrophin for 36 to 48 h, followed by insemination. Zygotes were randomly cultured either in conventional culture medium alone or in the co-culture system. Of 48 embryos cultured in conventional medium alone, all arrested at the 2-16- cell stage on day 3 after insemination. Of 46 embryos cultured in the co-culture system, 26 embryos (56.5%) arrested at the 2-16-cell stage. Six embryos (13%) developed to the morula stage. Fourteen embryos (30.4%) developed to expanded blastocysts and two blastocysts were hatching on day 7 after insemination. We conclude that co-culture significantly enhances the development of blastocysts in embryos resulting from IVM/IVF.