Leptin-induced increase in sympathetic nervous and cardiovascular tone is mediated by proopiomelanocortin (POMC) products

The mechanism underlying the leptin-induced increased sympathetic nerve activity and cardiovascular tone was investigated in normal rats. The melanocortin (MC) peptides and other fragments derived from proopiomelancortin (POMC) have a diverse array of biological activities and have been implicated in mediating the feeding behavioral responses to leptin. In this study we evaluated the possible involvement of two major products of POMC, alpha-melanocyte stimulating hormone (alpha-MSH) and beta-endorphin, in mediating the effects of leptin on sympathetic activity and mean arterial pressure (MAP) in normal rats. Intraventricular (i.c.v.) cannulas were implanted in normal rats and allowed to recover. On the day of the study the animals were anesthetized with urethane alpha-chloralose and instrumented for the recording of MAP, lumbar sympathetic nerve activity (LSNA), and heart rate (HR). To determine the correlation between the leptin response and the POMC products, alpha-MSH and beta-endorphins were also injected into the lateral ventricle. alpha-MSH acted to increase MAP and LSNA while beta-endorphin decreased these parameters. Leptin administration by i.c.v. cannula increased the MAP and LSNA in normal rats. The i.c.v. administration of agouti protein, an alpha-MSH receptor antagonist, prior to leptin infusion blocked this response. Likewise, pretreatment with naloxone a beta-endorphin receptor antagonist also blocked the response to leptin. From these studies we conclude that the acute increased LSNA and MAP in response to i.c.v. leptin may be mediated by increased POMC and its subsequent production of breakdown product alpha-MSH and/or beta-endorphin and it is the subsequent action of alpha-MSH that increases MAP and LSNA by activation of the MC4 receptor. The naloxone antagonism of the leptin response is likely due to the blockade of presynaptic opioid inhibition of the MC4 receptor-mediated pressor response.     

Divergent regulation of cell surface protease expression in HL-60 cells differentiated into macrophages with granulocyte macrophage colony stimulating factor or neutrophils with retinoic acid

Taking advantage of the recently demonstrated presence of N-aminopeptidasesand the serine protease dipeptidyi aminopeptidase IV (DPP IV)at the surface of human myeloblastic HL-60 cells, the regulationof these protease activities in HL-60 cell differentiation hasbeen assessed using combined spectrophotometric and flow cytometricassays. Addition of human recombinant granulocyte macrophagecolony stimulating factor (rHu-GM-CSF) to HL-60 cells to inducedifferentiation into macrophages led to a time and dose-dependentincrease in both cell surface N-aminopeptidase and DPP IV activities.Protease up-regulation was due to an enhancement in cell surfaceprotease number, associated with a slight rise in apparent affinitiesof the enzymes for their substrates. In contrast, in HL-60 cellsinduced to differentiate into neutrophils in the presenceofretinoic acid, expression of cell surface N-amlnopeptidaseswas almost completely abolished in a time-and dose-dependentfashion, and this down-regulation was accompanied by a weakbut significant decrease in affinity. However, no noticeabledifference was seen in serine DPP IV expression between retinoicacid-treated and untreated HL-60 cells. Retinoic acid treatmentalso reduced soluble protease activity in vitro indicating thatdown-regulation of membrane aminopeptldases was not due to theirproteolytic clip. No modulation in the activity of any of theenzymes tested was seen with human recombinant tumor necrosisfactor- or retinol which do not induce HL-60 cell differentiation.The up-regulation of cell surface protease expression in HL-60cells differentiated into macrophages was similar to that observedin monocytes isolated from peripheral blood: both DPP IV andN-aminopeptidase activities strictly increased on cells thatundergo macrophage maturation (up to 5-fold) and independentlyof the nature of the differentiation inducer. Thus, the distinctivepatterns of N-aminopeptidase and DPP IV expression that areseen in differentiating neutrophils and macrophages appear tobe relatedto differences in stage of myeloid maturation. Becausecell surface proteases are crucially involved in leukocyte functions,the data presented suggest that alterations in cell surfaceprotease expression are associated with events controlling thedifferentiation of immature cells.     

Granulocyte-macrophage colony stimulating factor does not improve neutrophil oxidative metabolism in a patient with variant X-linked chronic granulomatous disease

Variant X-linked chronic granulomatous disease (CGD) is characterised by a decreased but still measurable respiratory burst and cytochrome b content of phagocytes resulting in a clinically milder form of the disease. We examined the in vivo effect of recombinant human granulocyte-macrophage colony stimulating factor (rh-GM-CSF) on the neutrophil functions of a patient treated for liver abscess. The number of white blood cells was markedly increased at the highest dose of GM-CSF injected (30 g/kg per day). This was mainly due to a large increase in eosinophils and to a lesser extent in neutrophils. No change in the deficient neutrophil respiratory burst nitroblue tetrazolium (NBT)-reduction, superoxide (O ₂ ^– )-production and cytochrome b content was observed during 6 weeks of therapy with increasing doses of GM-CSF. No significant clinical improvement of the liver abscess was observed during treatment with GM-CSF.     

慢性心理刺激对生殖功能的影响

目的　探讨慢性心理应激因素对小鼠生殖功能的影响。方法　采用慢性心理应激的方法即悬吊法造成慢性心理刺激雌性小鼠模型 ,并观察其内生殖器湿质量、阴道脱落细胞指数、脑组织单胺类神经递质变化情况。结果　模型组与对照组比较内生殖器组织湿质量有极显著性差异 (P <0 .0 1) ;阴道脱落细胞角化指数有极显著性差异 (P <0 .0 1) ;脑组织中NE ,5 -HIAA的含量有极显著性差异 (P <0 .0 1)。结论　慢性心理应激状态能造成生殖功能抑制 ,这种现象的出现与脑组织中神经递质含量有关     

Present and future therapeutic strategies for idiopathic oligozoospermia

The effectiveness of medical treatment for idiopathic oligozoospermia (IO) has been at best doubtful until now and a logical consequence of this unsatisfactory situation has been the partial displacement of this approach by assisted reproduction techniques. This state of affairs has resulted from insufficient investigation, inappropriately designed clinical trials and consistent disregard for the principles of evidence-based medicine. Protocol-related shortcomings and wrong interpretation of the data available have also been some of the all too frequent problems encountered in this therapeutic approach. In this rather misty situation, it appears that, of the therapeutic agents used so far, follicle stimulating hormone (FSH) (mainly FSH-secretagogues) may exert some beneficial effects on a number of biological endpoints related to spermatogenesis and sperm maturation. The short and medium term prospects of medical treatment for IO rest mainly with improvement of investigative procedures to a higher degree of sophistication, with emphasis placed on identifying the causes rather than the results of dysfunction so that a better selection of candidates can be made. Moreover, the introduction of prognostic indices for evaluation of the beneficial effects of a therapeutic agent may be of paramount importance. Finally, a better assessment of the preparations available and, possibly, the introduction of new more specific agents may also be an important step forward in this field. This type of large-scale effort should not be left to individual investigators or special centres working independently, but it may come under the auspices of a central regulating agency so that undisputed results from large, multicentre and uniform studies might be obtained, if medical treatment is to remain a good option. In this context, it may also be emphasized that andrology's main task should always be to treat the male with the problem rather than his healthy female partner, whenever this is possible.     

mGM-CSF重组质粒的构建、表达及活性鉴定

目的 构建pc—mGM—CSF重组质粒载体，为mGM—CSF基因治疗肿瘤的研究奠定基础。方法 采用RT—PCR方法从小鼠脾脏中获得目的基因mGM—CSF，克隆于pcDNA3.1／Myc-His(-)(A)质粒上，成为pc-mGM-CSF，用PCR、酶切进行鉴定，然后用脂质体转染小鼠骨髓瘤细胞SP2／0，用G418筛选后通过RT—PCR和SDS—PAGE鉴定，将转染SP2／0上清加入NFS-60细胞，检测蛋白活性。结果 重组质粒中含有mGM—CSF基因，在SP2／0中有表达，且表达产物能分泌到肿瘤细胞外，分泌到细胞外的产物用mGM—CSF依赖株NFS-60细胞检测证明具有生物学活性。结论 成功构建含mGM—CSF真核表达重组质粒，有助于进一步研究其抗肿瘤作用。     

引流淋巴结树突状细胞对自身肿瘤细胞作用研究

目的　从胃癌患者引流淋巴结中分离和定向诱导培养扩增树突状细胞 (DC) ,观察其经自身肿瘤细胞抗原冲击后对自身细胞因子诱导的杀伤细胞 (CIK细胞 )杀伤活性的影响。方法　取手术切除肿瘤周围转移引流淋巴结 ,提取单个核细胞 ,将贴壁生长的细胞用细胞因子rhGM CSF、rhIL 4、rhTNF α联合诱导培养DC ,然后用自身肿瘤细胞抗原冲击DC并作用CIK细胞 ,最后检测CIK细胞杀伤三种靶细胞 (自身胃癌细胞、K5 6 2和SGC 790 1细胞 )的活性。结果　胃癌患者转移引流淋巴结中的贴壁细胞 ,经细胞因子联合诱导培养 ,DC含量可达 4 5 %。经自身肿瘤抗原冲击的引流淋巴结DC活化的CIK细胞 ,杀伤自身肿瘤细胞活性达 79 3% ,单纯CIK细胞为 33% ,两者比较差异有显著意义 (P <0 0 1) ;而对K5 6 2和SGC 790 1细胞杀伤活性无明显差异。结论　肿瘤周围转移引流淋巴结贴壁细胞在体外能定向诱导扩增出大量DC :DC经自身肿瘤抗原冲击后能明显提高CIK细胞对自身肿瘤细胞的杀伤活性。此结果为肿瘤DC的免疫治疗应用奠定了理论基础     

低剂量粒—巨噬细胞集落刺激因子在肺癌化疗中的应用

３１例肺癌患者大剂量化疗４０例次，采用配对法分成加用低剂量粒－巨噬细胞集落刺激因子（ＧＭ－ＣＳＦ）的治疗组及不加用的对照组（二组均为２０例次）。结果表明，低剂量ＧＭ－ＣＳＦ明显缩短化疗所致白细胞低下的时间：治疗组为１４．５±９．４９天，对照组为１９．４±８．８５天（Ｐ＝０．０２），同时提高白细胞下降最低值：治疗组为３．３５×１０９／Ｌ±１．３７×１０９／Ｌ，对照组为２．９×１０９／Ｌ±１．１８×１０９／Ｌ。低剂量ＧＭ－ＣＳＦ的主要不良反应为发热（８０％）及肌痛、骨痛（１０％）。结果提示：低剂量ＧＭ－ＣＳＦ能支持癌症患者的大剂量化疗及连续化疗     

Increased hepatobiliary clearance of unconjugated thyroxine determines DMP 904-induced alterations in thyroid hormone homeostasis in rats.

4-(3-pentylamino)-2,7-dimethyl-8-(2-methyl-4-methoxyphenyl)-pyrazolo-[1,5-a]-pyrimidine (DMP 904) is a potent and selective antagonist of corticotropin releasing factor receptor-1 (CRF1 receptor) with an efficacious anxiolytic profile in preclinical animal models. In subchronic toxicity studies in Sprague-Dawley rats, DMP 904 produced thyroid follicular cell hypertrophy and hyperplasia, and a low incidence of follicular cell adenoma. The current investigations were designed to determine the mode of action by which DMP 904 disrupts thyroid homeostasis in male rats. Five-day treatment with DMP 904 (300 mg/kg/day) dramatically lowered serum thyroxine (T4) to levels below detectable limits (< 1 microg/dl) by 72 h, with concurrent decreases in triiodothyronine (T3, about a 70% decrease) and increases in thyroid stimulating hormone (TSH; about a three-fold increase). DMP 904 increased [125I]T4 total body clearance (Cl tb) (38.21 +/- 10.45 ml/h) compared to control (5.61 +/- 0.59 ml/h) and phenobarbital-treated rats (7.92 +/- 1.62 ml/h). This increase in Cl(tb) was associated with a significant increase in biliary clearance (Cl bile) of unconjugated [125I]T4 (nearly 80-times control rates) and increased liver:blood ratios of T4, suggestive of enhanced hepatic uptake of T4. A single dose of DMP 904 (200 mg/kg) increased mRNA levels of hepatic cytochrome P450s (CYP 3A1 and CYP 2B1) and UDP-glucuronosyltransferases (UGT 1A1 and UGT 1A2). DMP 904 also induced mRNAs of the canalicular transporter, multi-drug resistance protein-2 (Mrp2) and sinusoidal transporters, organic anion transporting proteins (Oatp1 and Oatp2) within 24 h. Western blot analysis confirmed DMP 904 related increases in Oatp2 protein expression. Collectively, these data suggest that DMP 904 is an agonist of the constitutive androstane receptor (CAR) and pregnane X receptor (PXR) and that the decreased serum levels of T4 and T3 resulted from increased hepatobiliary clearance. However, DMP 904 is distinguished from other compounds associated with similar effects on thyroid hormone homeostasis because its effects were primarily related to increased biliary excretion of unconjugated T4.