Endogenous vasopressin and baroreflex mechanisms

This article reviews the anatomical and functional evidence for ascending pathways from specific brain regions to the PVN and SON which could influence AVP release. The majority of evidence favours the main projection being from a region in the caudal VLM which may coincide with the noradrenergic neurons of the A₁ cell group. However, the transmitter(s) involved have yet to be identified, and whether the pathway is excitatory and/or inhibitory remains to be fully resolved.Anatomical and functional evidence is reviewed for descending projections from the SON and PVN to specific brain regions involved in cardiovascular control, and their possible involvement in baroreflex mechanisms is discussed. However, there is little unequivocal evidence that AVP is the main neurotransmitter utilized by descending projections from PVN to NTS and DMX. While, in some situations, circulating endogenous AVP exerts cardiovascular effects, details of its putative influences on baroreflex mechanisms are lacking.     

Uptake of dehydroascorbic acid in high-GSH and normal-GSH dog erythrocytes

Uptake of dehydroascorbic acid (DHA) was studied in two types of dog erythrocytes with high GSH and normal GSH levels. Compared with ascorbic acid uptake, DHA produced a much greater ascorbic acid accumulation in dog erythrocytes. Both dog erythrocytes showed a concentration dependence of DHA uptake, and cellular ascorbic acid concentrations were significantly higher in high-GSH cells than in normal-GSH cells. Glucose and cytochalasin B inhibited DHA uptake. This suggests that DHA enters dog erythrocytes predominantly by the facilitated glucose transporter, particularly by the Glut 1 glucose transporter. The rate of glucose uptake was quite similar in the two types of cells. Compared with normal-GSH cells, high-GSH cells were more resistant to oxidative stress induced by high concentration of DHA. As a rapid entry of DHA inflicts on cells a heavy demand for GSH for its reduction to ascorbic acid, high-GSH cells containing a larger reserve of GSH have an advantage over normal-GSH cells in both ascorbic acid accumulation and resisting oxidative stress produced by DHA.     

Homologous testis transplantation in dogs

There is growing interest in the possible use of homologous testis transplantation for the treatment of anorchia and male infertility. In order to test the surgical and immunological feasibility of this therapy, three series of experimental studies of homologous testis transplantation were carried out in dogs. In the first pilot study, four beagles from the same litter were transplanted using microsurgical techniques for end-to-end anastomosis of the testicular vessels and the vas deferens. These dogs received cyclosporin A (CyA) for 3 months after transplantation. The longest functional graft survival in this series was 163 days, strongly suggesting that long-term survival of a homologously transplanted testis graft is possible. A second series of operations was performed on ten mongrel dogs. The same surgical technique was employed and the series was divided into three groups. Group 1 received CyA monotherapy, group 2 a combination of CyA and prednisolone, and group 3 received no immunosuppression. The average graft survival time in this series was 18 days, significantly less than the 71 days in the first series. The dogs in group 2, however, had graft survival times that were three times longer than those in the other two groups, suggesting that CyA in combination with prednisolone yields the best graft survival. In the third series, five littermates received a testis graft after castration. Immunosuppression was achieved by administration of CyA and prednisolone for 3 months. In three out of five animals, the graft survived until the immunosuppressive therapy was suspended. Histological biopsies of the graft 3 months after transplantation showed the same maturation of sperm cells as in the control testis of the same dog. The results of the last series suggest that long-term survival of homologously transplanted testis grafts in dogs is, indeed, possible with the aid of CyA and prednisolone. Received: 14 August 1996 Received after revision: 21 March 1997 Accepted: 24 April 1997     

狗脊髓截除自体隐神经大网膜移植的初步观察

实验用6只狗于T13处切除脊髓8mm，局部用隐神经、大网膜移植。对照组6只狗单纯切除脊髓8mm。术后3个月、6个月实验组动物全部恢复到C／Ⅲ级功能，组织学切片见移植神经有不同程度存活，可记录到股四头肌、胫前肌电位。对照组动物仅达到0／0～A／I织功能，组织学切片见脊髓缺损处为结缔组织，诱电位波形消失。分析了影响脊髓神经功能恢复的原因。     

Ex Vivo Evaluation in Normal Dogs of Insulin Released by a Bioartificial Pancreas Containing Isolated Rat Islets of Langerhans

In bioartificial pancreatic systems, isolated islets of Langerhans are protected against immune rejection by an artificial membrane, permeable to glucose and insulin, but not to immunoglobulins and lymphocytes. Some of these devices, referred to as vascular systems, are set up to be connected to a vascular site in the recipient, with blood circulating in contact with one side of the membrane, and the islets on the other side. Such a bioartificial pancreas, containing isolated rat islets of Langerhans, was connected to an arteriovenous shunt of a normal anesthetized dog. The aim of this experiment was to investigate the kinetics of the insulin secretory response of the system to a glucose load. Glucose was infused upstream of the system, increasing the glucose concentration inside the bioartificial pancreas from 7 to 14 mmol/l, without altering the blood glucose concentration of the dog. Insulin concentration was determined simultaneously upstream and downstream of the bioartificial pancreas. Insulin production was calculated by multiplying the difference between these values by the blood flow rate. Blood flow rate (Q) was estimated from the change in the glucose concentration produced by the glucose infusion using a mass transfer analysis derived from Fick's principle. Insulin production increased from 20 +/- 8 to 59 +/- 15 microU/100 islets/min within 15 min following the beginning of the stimulation (n = 6, p less than 0.05). Five min after the end of the stimulation, insulin production decreased from 75 +/- 13 to 50 +/- 9 microU/100 islets/min (p less than 0.05) to reach the basal level (21 +/- 3 microU/100 islets/min) 30 min after the end of the glucose stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)     

长段同种异体骨与自体活骨复合移植的实验研究

目的 研究长段同种异体骨与带血管腓骨套叠式复合骨移植体的愈合机制和规律。方法 采用健康成年杂种犬36只胫骨结节下切除3．0cm骨干和骨膜实验动物模型。随机分为实验组和对照组。实验组植入深低温保存的同种异体骨与带血管自体腓骨，对照组仅植入深低温保存的同种异体骨，均用7孔93cmAO加压钢板内固定及石膏外固定。术后1、2、3、4个月分别行X线摄片、ECT检查、大体标本及组织学观察。结果 X线示实验组较同时期对照组异体骨吸收、新骨形成明显，第4个月实验组宿主骨一异体骨接合部愈合率83．3％，对照组未愈合或不愈合。ECT检查：实验组较同期对照组骨代谢活跃，但变化规律相似，均为术后1、2个月活跃，于第2个月达高峰，第3、4个月呈下降趋势。组织学观察：实验组较同期对照组异体皮质骨髓腔内壁及哈佛管内的内吸收、成骨活动显著增强。结论 长段同种异体骨与带血管自体腓骨复合移植修复骨缺损效果良好，带血管自体腓骨能促进长段同种异体骨的血管化，加速其爬行替代过程。     

广东省部分医院狗咬伤病例流行病学分析

目的了解广东省人群狗咬伤流行病学特征,为制定干预措施提供科学依据。方法在广东省随机抽取城市点珠海市、一类农村新兴县、二类农村南雄市和连平县,城市点选择1家三级医院、2家二级医院;农村点选择1家县级医院、1~2家乡卫生院共10家医院作为哨点医院。监测对象为2006年1-12月到哨点医院就诊的狗咬伤首诊患者。采用中国疾病预防控制中心慢病中心统一制定的《全国伤害监测报告卡》,由各监测哨点医院医生或护士填报门诊急诊狗咬伤首诊患者。结果共监测1 585例狗咬伤病例,狗咬伤病例占医院伤害监测病例的4.8%,其中农村占6.2%~13.5%,城市仅占2.6%。狗咬伤病例中,男女性别比为1∶0.75;6~14岁组构成比最高(26.6%);在校学生与学龄前儿童占44.3%;患者初中学历及以下为主(占78.9%);咬伤的部位主要在上下肢(占91.9%),咬伤性质以开放性伤为主(占93.7%),发生在家中和休闲活动分别为55.1%、70.0%;咬伤时间多在7、8和10月份;有86.9%的病例在24 h内到医院接受治疗。结论狗咬伤在广东省农村地区较为严重,应重点干预0~14岁人群。     

Monoclonal antibodies to canine intra-acrosomal sperm proteins recognizing acrosomal status during capacitation and acrosome reaction

Summary.  Monoclonal antibodies Ds-1 and Ds-2 specifically labelling dog sperm acrosome were prepared by immunization of mice with acetic acid extracts of dog spermatozoa. Electron microscopy and indirect immunofluorescence localized the site of Ds-1 and Ds-2 proteins inside the acrosomal vesicle. Ds-1 antibody detected 55, 76, 115, 120 and 190kDa proteins under non-reducing conditions, and 73 kDa and 54 kDa proteins after reduction (p73/Ds-1 and p54/Ds-1). 92 kDa and 40 kDa proteins recognized by Ds-2 (p92/Ds-2 and p40/Ds-2) migrated at > 200 kDa in the absence of reducing agent. In vivo , p73/Ds-1 and p54/Ds-1 are therefore likely to be present both in free and complexed form, while all of p92/Ds-2 and p40/Ds-2 form disulfide-bonded complexes. Decrease in the rate of acrosomes stained with Ds-1 and Ds-2 was correlated with the progress of capacitation resulting in the increased rate of spontaneous acrosome reactions, as suggested by a dramatic effect of A23187. Monoclonal antibody to boar acrosin (ACR-2) recognized dog sperm acrosin homologue. A higher rate of ACR-2-negative spermatozoa was observed after capacitation and A23187 treatment compared to Ds-1 and Ds-2, indicating that proteins recognized by Ds-1 and Ds-2 are localized in a specific compartment of acrosome, distinct from acrosin and possibly representing fraction of acrosomal matrix.     

狗喉上神经袢神经束性质的鉴别

用成年杂种狗１２只，在全麻状态下放血，取其颈交感干与喉上神经外支间的交通支及其与喉上神经外支汇合后的神经干，甲醛固定，明胶包埋，恒冷切片后用Ｋａｒｎｏｖｓｋｙ乙酰胆碱酯酶组化方法，对上述材料进行观察。我们发现交通支多为无髓纤维，酶反应呈强阳；混合后的神经含有髓酶反应阳性和阴性纤维及无髓酶反应强阳性纤维，证实喉上神经袢含有体躯运动、内脏运动（交感神经）纤维及感觉纤维。因此，喉上神经拌为混合神经。