INTERACTION BETWEEN EPIDERMAL GROWTH FACTOR AND ARGININE VASOPRESSIN IN RENAL MEDULLARY MEMBRANES

1. Epidermal growth factor is a potent mitogen that causes natriuresis, diuresis and inhibition of arginine vasopressin-induced water reabsorption. 2. The aim of this study was to determine any interaction between epidermal growth factor and the V1 (vascular) and/or V2 (antidiuretic) arginine vasopressin receptor subtypes. 3. Radioligand binding displacement assays demonstrated that although arginine vasopressin related peptides displaced both radioligands from renal medullary membranes at low concentrations epidermal growth factor displaced neither. 4. Arginine vasopressin V2 receptor second messenger cyclic adenosine monophosphate (CAMP) production was inhibited by epidermal growth factor (IC₅₀ 2 ± 10^?7 mol/L) as was sodium fluoride cAMP production but only at much higher concentrations. 5. Therefore the diuretic effect of epidermal growth factor is not via direct antagonism of arginine vasopressin receptors but seems mediated via inhibition of the V2 second messenger system.     

Oral sensorimotor therapy: Assessment,efficacy and future directions

This review addresses the current state of knowledge in oral sensorimotor therapy for children with neurological impairments and ingestive problems. Comprehensive assessment of the child with dysphagia looks at the interaction of oral performance and growth. These domains include eating efficiency, oral-motor skills, oral sensory evaluation, classification of the severity of an eating problem, interaction of respiration and ingestion, aspiration, positioning for feeding, social skills assessment, careload and assessment technologies. Oral sensorimotor therapy improves eating but not drinking skills in children 3–12 years of age. Weight gain is sufficient so that children maintain their growth channel but they do not show catchup growth. Many factors thought to contribute to better ingestive performance need further study, such as jaw and lip control in association with drinking. The earliest possible identification of infants at risk for eating impairments needs to be rigorously pursued. Such an approach offers hope that the later growth deterioration now seen in children with eating impairments may be prevented. Finally, the effect of positioning and the use of eating equipment to promote self-feeding need further study.     

Study of nerve regeneration in centrocentral anastomosis

Summary Nerve regeneration was studied in a model of centrocentral anastomosis (CCA) performed on the sciatic nerve of the rat. Experimental CCA was made by suturing the proximal end of the peroneal branch on the proximal end of the sural branch, placing between them a peroneal nerve graft (Group I, 20 rats) or a silicone chamber (Group II, 12 rats). Nerve grafts had a length of 5mm and silicone chambers 7 mm. In six silicone chambers an 1 mm nerve graft was placed in the centre of the tube. In group I animals anterograde degeneration was studied by cutting the graft 60 days after surgery. In group II, nerve regeneration was studied 2, 4 and 8 weeks after surgery. Results indicate that in CCA: 1) regenerated axons coming from one nerve end grow into the graft but do not cross the contralateral suture line; 2) regeneration is poorer in silicone chambers than in nerve grafts; and, 3) in silicone chambers regeneration is related to time. The reduction in the regenerative capability in CCA seems to be related to the alteration of nerve sprouts aiming for the peripheral targets.     

地膜覆盖条件下红花生长发育规律及其与产量关系的研究

对地膜覆盖条件下红花生长发育规律及其与产量的关系进行了研究。结果表明,地膜红花与露地红花生长发育规律基本一致,但地膜红花生育进程明显提前,各个阶段的生长量明显增多,花的产量及籽粒产量极显著提高。     

Comparative effects of plateletderived growth factor-BB and insulin-like growth factor-I, individually and in combination, on periodontal regeneration in Macaca fascicularis

Platelet-derived growth factor (PDGF) and insulin-like growth factor I (IGF-I) in combination have previously been shown to enhance periodontal regeneration. The objective of this study was to further characterize the biological effects of this combination of growth factors in non-human primates and compare the effects to those of each growth factor individually. Ligature-induced periodontitis was initiated in 10 cynomolgus monkeys. After periodontal lesions were established, surgery was performed, and either a methylcellulose gel vehicle or vehicle containing 10 μg each of either PDGF-BB, IGF-I or both PDGF-BB and IGF-I was applied to exposed root surfaces. Biopsies were taken 4 and 12 wk after treatment and the extent of periodontal regeneration was assessed by histomorphometry. At both 4 and 12 wk vehicle-treated lesions generally revealed minimal osseous defect fill (ODF) (8.5±2.1% and 14.5±5.7%, respectively) and new attachment (NA) (34.1±5.2% and 26.6±10.5%, respectively). IGF-I treatment did not significantly alter healing compared to vehicle in any parameter at both 4 and 12 wk. PDGFBB-treated sites exhibited significant (p<0.05) regeneration of NA (69.6±12.0%) at 12 wk; trends for PDGF-BB treatment effect were also observed in other parameters at 4 and 12 wk. although these increases were not statistically significant. Treatment with PDGF-BB/IGF-I resulted in 21.6±5.1 % and 42.5±8.3% ODF at 4 and 12 wk, respectively, and 64.1±7.7% and 74.6±7.4% NA at 4 and 12 wk, respectively (all significantly greater than vehicle, p<0.05). The results from this study demonstrated that: 1) IGF-1 alone at the dose tested did not significantly alter periodontal wound healing; 2) PDGF-BB alone significantly stimulated NA, with trends of effect on other parameters; and 3) the PDGF-BB/IGF-I combination resulted in significant increases in NA and ODF above vehicle at both 4 and 12 wk.     

Muscle growth and myosin isoform transitions during development of a small teleost fish, Poecilia reticulata (Peters) (Atheriniformes, Poeciliidae): a histochemical, immunohistochemical, ultrastructural and morphometric study

The myosin composition of lateral muscle in Poecilia reticulata from birth to adult was studied by ATPase histochemistry and immunostaining with myosin isoform-specific antibodies. At birth the muscle consists of two layers containing developmental isoforms of myosin. In deep layer fibres the developmental myosin is replaced by the adult fast-white isoform soon after birth. In the epaxial and hypaxial monolayer fibres the myosin composition present at birth (J1) is replaced within 3 days by another (J2). In some fibres, this J2 composition is retained in the adult, but in others it is slowly replaced by the adult slow-red muscle isoform. Close to the lateral line, all monolayer fibres are already in transition between the J2 myosin and the adult slow-red form at birth, and rapidly complete the transition to slow-red form. These fibres, together with others generated de novo in an underlying hyperplastic zone, form the red muscle layer of the adult. The pink muscle develops during the first month after birth, and by 31 days it consists of an outer, middle and inner layer. A few middle layer fibres are already present at birth, while the outer layer fibres first appear 3 days after birth. The thin inner layer is probably a transitional form between the middle pink and adult white types, and appears at about 31 days. A morphometric analysis showed that growth of the white muscle occurs principally by hypertrophy. Even at the magnification level of the electron microscope, no satellite cells or myoblasts which could give rise to new fibres were found in the white muscle, except in the far epaxial and hypaxial regions and only in the first 10 days. A zone of hyperplastic growth was also found lying just under the superficial monolayer close to the lateral line, and this presumably contributes fibres to the red and pink muscle layers.     

Overexpression of suppressor of cytokine signalling-5 augments eosinophilic airway inflammation in mice

BACKGROUND: Enhanced expression of the suppressor of cytokine signalling (SOCS)-5 might be of therapeutic benefit for T-helper type 2 (Th2) dominant diseases, as its expression is reported to result in a reduction of Th2 differentiation in vitro due to the inhibition of IL-4 signalling. OBJECTIVE: To investigate the regulatory role of SOCS-5 in vivo, we explored the phenotype of an experimental asthma model developed in SOCS-5 transgenic (Tg) mice. METHODS: The SOCS-5 Tg mice or wild-type (WT) mice were sensitized and repeatedly challenged with ovalbumin (OVA). We examined bronchoalveolar lavage fluid (BALF), lung specimens, and airway hyperresponsiveness (AHR) to methacholine. RESULTS: The production of IFN-gamma by CD4(+) T cells from unprimed SOCS-5 Tg mice was significantly increased in comparison with unprimed wild-type mice, indicating that SOCS-5 Tg mice have a Th1-polarizing condition under natural conditions. However, in an asthma model, significantly more eosinophils in the airways and higher levels of IL-5 and IL-13 in BALF were observed in the SOCS-5 Tg than the wild-type mice. AHR in the asthma model of SOCS-5 Tg was also more enhanced than that of wild-type mice. OVA-stimulated CD4(+) T cells from the primed SOCS-5 Tg mice produced significantly more IL-5 and IL-13 than CD4(+) T cells from wild-type mice. CONCLUSION: Our results demonstrate that the overexpression of SOCS-5 does not inhibit Th2 response, but rather augments the phenotype of the asthma model in vivo. This finding throws into question the therapeutic utility of using enhancement of SOCS-5 expression for Th2-dominant disease.     

垂体腺瘤细胞VEGF表达与细胞因子分泌的关系

目的:探讨垂体腺瘤细胞株HP75 VEGF表达与细胞因子IL-1α和IL-6分泌的关系。方法:HP75细胞常规培养,经各种因素处理后,取培养上清液,采用ELISA方法分别检测VEGF、IL-1α和IL-6的分泌水平。结果:①HP75细胞时间依赖性分泌VEGF、IL-1α和IL-6;②较大剂量的IL-1α剂量依赖性的刺激VEGF表达;③所用各种剂量的IL-6对VEGF的分泌均无显著影响;④IL-1α和IL-6中和抗体对VEGF基础分泌无显著影响。结论:VEGF的表达与IL-1α和IL-6的分泌密切相关,提示细胞因子在垂体腺瘤的生长过程中发挥重要作用。     

人工合成成骨生长肽对辐射损伤小鼠造血功能的保护作用

目的　探讨人工合成成骨生长肽 (sOGP)对辐射损伤小鼠造血功能的保护作用 ,阐明其剂量 效应关系。方法　以 4 .0和 7.5Gy13 7Csγ射线照射小鼠为模型 ,采用皮下注射和肌肉注射 2种给药途径连续 8d给予sOGP ,剂量范围为 0 .0 39～ 6 4 0nmol/(kg·d) ,观察外周血象、骨髓有核细胞数、骨髓粒系造血祖细胞集落形成(CFU G)、骨髓细胞分类和骨髓切片组织学等的变化。结果　sOGP能加快受照小鼠外周血白细胞、骨髓有核细胞数的恢复 ,在一定的剂量范围内呈明显的剂量依赖性 ,并能刺激髓外造血 ;促进 (CFU G)形成作用显著高于重组人粒系集落刺激因子 (rhG CSF)约 2倍 ;骨髓病理学观察显示sOGP能加快受照小鼠骨髓造血组织损伤的恢复 ,刺激骨髓粒系增生。结论　sOGP可明显促进受照射小鼠造血功能的恢复 ,其机制可能是通过作用于早期造血阶段或 (及 )改善微环境进而促进造血。     

质粒pGH/BL_(21)在大肠杆菌中表达条件的研究

目的　寻找质粒 pGH/BL2 1在大肠杆菌中的最佳表达条件。方法　当它在大肠杆菌中表达时 ,考查不同IPTG诱导浓度及不同的诱导时间对表达产物的影响 ,表达产物的量以SDS -PAGE电泳方法分析。结果　该基因的最佳表达条件为 :IPTG诱导浓度 1.0mmol/L ,诱导时间 4h。结论　IPTG对不同的基因在不同的表达体系中需不同的诱导条件 ,只有找到它的最佳诱导条件才能保证终产物的最大产率