Role of vasoactive intestinal polypeptide in the internal anal sphincter relaxation of the opossum.

The nature of the inhibitory neurotransmitter responsible for internal anal sphincter (IAS) relaxation in response to rectoanal reflex is not known. The objective of the present investigation was to examine the role of VIP in IAS relaxation in response to the rectoanal reflex in intact opossums with the use of VIP antagonists, [4CI-D-Phe6,Leu17] VIP and (N-AC-Tyr1,D-Phe2)-GRF (1-29)-NH2. Intraluminal pressures from the sphincter were monitored using low-compliance, continuously perfused catheters. VIP and the antagonists were administered close-intraarterially. The responses to VIP, rectoanal reflex, sacral nerve stimulation, and local intramural stimulation were examined before and after the VIP antagonists. The present studies in intact animals show: (a) VIP causes a dose-dependent fall in the IAS pressures by a direct action at the IAS smooth muscle; (b) VIP antagonists selectively and significantly antagonized the inhibitory action of VIP; and (c) VIP antagonists caused significant antagonism of the IAS relaxation caused by rectoanal reflex and the other neural stimuli. The antagonism of the IAS relaxation by the VIP antagonists, depending upon the volume of rectal distension used, ranged from 40% to 62% (P less than 0.05). From these results, we conclude that VIP acts as an inhibitory neurotransmitter for IAS relaxation during the rectoanal reflex.     

非亲缘外周血造血干细胞移植治疗重型β-地中海贫血1例

患儿,女,4岁,体质量19kg。生后4个月开始进行性面色苍白伴巩膜黄染,血红蛋白65g/L,白细胞和血小板均正常,血红蛋白电泳血红蛋白A48.1%、血红蛋白A24.2%、抗碱血红蛋白47.7%,基因型为β地贫纯合子,诊断为重型β地中海贫血,以间断大量输血维持生命。于2005-12-09在厦门大学附属中山医院血液科接受非亲缘性外周血干细胞移植。预处理方案采用常规氟达拉滨、白消胺、环磷酰胺三药联合方案,以环孢菌素A、霉酚酸酯、抗胸腺淋巴细胞免疫球蛋白联合预防移植物抗宿主病,供受者人类白细胞抗原高分辨全相合,ABO血型次要不合(O-A),输入CD34 干细胞11.4×106/kg。植入成功,移植后12d中性粒细胞>0.5×109L-1,移植后37d血小板>50×109L-1,移植后35d患者血型检测转变为供者血型,患儿血红蛋白达到100g/L的时间是28d,移植后患儿未再输血,血红蛋白维持130g/L以上,整个移植过程顺利,未出现严重感染和移植物抗宿主反应,随访18个月,患儿生活正常,发育良好。     

In vitro low-level resistance to azoles in Candida albicans is associated with changes in membrane lipid fluidity and asymmetry

The present study tracks the development of low-level azole resistance in in vitro fluconazole-adapted strains of Candida albicans, which were obtained by serially passaging a fluconazole-susceptible dose-dependent strain, YO1-16 (fluconazole MIC, 16 microg ml(-1)) in increasing concentrations of fluconazole, resulting in strains YO1-32 (fluconazole MIC, 32 microg ml(-1)) and YO1-64 (MIC, 64 microg ml(-1)). We show that acquired resistance to fluconazole in this series of isolates is not a random process but is a gradually evolved complex phenomenon that involves multiple changes, which included the overexpression of ABC transporter genes, e.g., CDR1 and CDR2, and the azole target enzyme, ERG11. The sequential rise in fluconazole MICs in these isolates was also accompanied by cross-resistance to other azoles and terbinafine. Interestingly, fluorescent polarization measurements performed by using the fluorescent probe 1,6-diphenyl-1,3,5-hexatriene revealed that there was a gradual increase in membrane fluidity of adapted strains. The increase in fluidity was reflected by observed change in membrane order, which was considerably decreased (decrease in fluorescence polarization values, P value) in the adapted strain (P value of 0.1 in YO1-64, compared to 0.19 in the YO1-16 strain). The phospholipid composition of the adapted strain was not significantly altered; however, ergosterol content was reduced in YO1-64 from that in the YO1-16 strain. The asymmetrical distribution of phosphatidylethanolamine (PE) between two monolayers of plasma membrane was also changed, with PE becoming more exposed to the outer monolayer in the YO1-64 strain. The results of the present study suggest for the first time that changes in the status of membrane lipid phase and asymmetry could contribute to azole resistance in C. albicans.     

The multiple mediators of neurogenic smooth muscle relaxation.

The regulation of smooth muscle relaxation is vitally important for normal functioning of respiratory airways, gastrointestinal organs and the circulatory system. Since the recognition that such relaxation is not under adrenergic or cholinergic control, there has been an active search for the nonadrenergic, noncholinergic (NANC) mediators. A recent paper highlights the complex but coordinated control of the internal anal sphincter by three neurotransmitters.     

Longevity mutants do not establish any “new science” of ageing

The biological reasons for ageing are now well known, so it is no longer an unsolved problem in biology. Furthermore, there is only one science of ageing, which is continually advancing. The significance and importance of the mutations that lengthen the lifespan of invertebrates can be assessed only in relationship to previous well-established studies of ageing. The mutant strains of model organisms that increase longevity have altered nutrient signalling pathways similar to the effects of dietary restriction, and so it is likely that there is a shift in the trade-off between reproduction and maintenance of the soma. To believe that the isolation and characterisation of a few invertebrate mutations (as well as those in yeast) will “galvanise” the field and provide new insights into human ageing is an extreme point of view which does not recognize the huge progress in ageing research that has been made in the last 50 years or so.     

Tear break-up time in high altitude areas

Background: In high altitude areas, patients report with irritation, redness and foreign body sensation in their eyes suggesting tear film abnormality due to low humidity and windy environmental conditions.     

Nutritional intervention during maxillomandibular fixation of jaw fractures prevents weight loss and improves quality of life

Maxillomandibular fixation (MMF) for the management of jaw fractures leads to compromised nutritional intake and consequent weight loss and poor quality of life (QoL). The present study aimed to evaluate the effectiveness of a home-based dietary plan to prevent weight loss, and its effect on the QoL of patients who underwent four weeks of MMF for the treatment of maxillofacial fractures. A total of 50 patients were randomised into nutritional intervention (Group1) and non-intervention groups (Group 2). Patients in Group1 were counselled by a dietitian and given a diet plan. Patients in Group 2 were advised to take a liquid diet of their own choice in the form of shakes, juices, and milk, along with protein supplements. Patients in Group1 lost significantly less weight than those in Group 2 (p=0.001) at week four of follow up. Group1 patients had significantly better oral health-related QoL in the ‘physical pain’ domain during the two weeks of MMF, and in the ‘physical discomfort’ and ‘psychological disability’ domains two weeks after the release of MMF. They had significantly better nutrition-related QoL in all the domains during the two weeks of MMF and, except for the ‘physical’ domain, also during the two weeks after its release. Individual home-based diet plans effectively helped the patients maintain their weight and improved QoL.     

Basal internal anal sphincter tone,inhibitory neurotransmission,and other factors contributing to the maintenance of high pressures in the anal canal

Maintenance of the basal tone in the internal anal sphincter (IAS) is critical for rectoanal continence. Effective evacuation requires a fully functional rectoanal inhibitory reflex (RAIR)‐mediated relaxation of the IAS via inhibitory neurotransmission (INT). Systematic studies examining the nature of the INT in different species have identified nitric oxide (NO) as the major inhibitory neurotransmitter. However, other mediators such as vasoactive intestinal polypeptide (VIP), ATP, and carbon monoxide (CO) may also play species‐specific role under certain experimental conditions. Measurements of the intraluminal pressures in the IAS along with the force of the isolated IAS tissues are the mainstay in the basic studies for the molecular mechanisms underlying the basal tone and in the nature of the INT. The identification of NO as the inhibitory neurotransmitter has led to major advances in the diagnosis and treatment of a number of rectoanal motility disorders associated with the IAS dysfunction. Besides the IAS, the high pressures in the anal canal are affected by the external anal sphincter (EAS) function, and its malfunction may also lead to rectoanal incontinence. Different approaches including biofeedback have been attempted to improve the EAS function, with variable outcomes. There is a dire need for the innovative ways to improve the week high pressures zone in the anal canal. This viewpoint focuses on two studies that extend the above concept of multiplicity of inhibitory neurotransmitters ( Neurogastroenterol Motil 2011 23 e11–25 ), and that high pressures in the anal canal can be improved by the EAS plication ( Neurogastroenterol Motil 2011 23 70–5 ).