Concentrations and distribution of vasoactive intestinal peptide (VIP), peptide histidine isoleucine (PHI) and peptide histidine valine (PHV) in the cerebral cortex and the suprachiasmatic nucleus of the mouse

Prepro-vasoactive intestinal peptide (prepro-VIP) is processed to at least three biologically active peptides: VIP, peptide histidine isoleucine (PHI) and an extended PHI, peptide histidine valine (PHV). The aim of the present investigation was by chromatography combined with RIA and immunocytochemistry to determine which of these peptides were present in the cerebral cortex and the hypothalamic suprachiasmatic nucleus (SCN) of the mouse. These regions were chosen since they are known to contain a high concentration of VIP but the relative concentration of PHI and PHV is not known. Tissue was extracted and subjected to gel chromatography and high-pressure liquid chromatography (HPLC). VIP and PHI immunoreactivities co-eluted with synthetic rat VIP and PHI. A minor peak of PHI and prepro-VIP(111–122) immunoreactivities eluted at the position of synthetic PHV. Surprisingly, a major peak of prepro-VIP(111–122) immunoreactivity eluted in a position not related to any other immunoreactivity indicating the presence of prepro-VIP(111–122). Measurements of these immunoreactivities in cortical and suprachiasmatic extracts revealed that VIP was found in the highest concentration whereas PHV was found in the lowest. Immunoreactivity for PHI and prepro-VIP(111–122) was found in moderate concentrations. Except for prepro-VIP(111–122) which was found to be 3×higher concentrated in the SCN than in the cerebral cortex, the other immunoreactivities were found in almost similar relative concentrations in the two tissues. Using immunocytochemistry, elongated neurons mostly of the bipolar type with prominent processes observed in the cerebral cortex reacted with all antisera tested. More PHI/PHV/prepro-VIP(111–122)- than VIP-immunoreactive (ir) nerve fibers were found in the cerebral cortex. In the SCN, the density of immunoreactivity was the same whatever antiserum used. VIP-, PHI- and prepro-VIP(111–122)/PHV-ir neurons were observed in the ventral part of the nucleus with numerous axons coursing caudodorsally into the subparaventricular area. A substantial number of terminals was detected caudal to the paraventricular nucleus. Minor projections spread to the medial part of the anterior nucleus and to the medial preoptic area hypothalamic. These data show that VIP and PHI are the major active peptides derived from prepro-VIP in the mouse cerebral cortex and SCN whereas PHV was found in minor concentrations. Prepro-VIP(111–122), which so far has been found to have no functional significance, is, therefore, most likely a vaste fragment of processing of PHI in central neurons. The presence of all these peptides in axons indicate that the neurotransmission involving VIP is more complex, due to roles of other peptides processed from the same prepro-VIP molecule.     

Novel rhodamine tripeptide substrate for manual and automated colorimetric prothrombin time test

A chromogenic prothrombin time test is described using the tripeptide substrate, (Sar-Pro-Arg)2-Rhodamine 110. The method is both precise and sensitive to the factors of the extrinsic pathway. The accuracy of the method was demonstrated by comparison of patient sample values to standard clotting test results. The manual substrate test was adapted to two different automated chemistry analyzers.     

Inhibitory effect of tripeptides containing L-Phe-L-Tyr on neuronal excitability.

Eight tripeptides containing L-Phe-L-Tyr were synthesized, and their effects on the excitability of a giant neurone (tonically autoactive neurone, TAN), identified in the suboesophageal ganglion of an African giant snail (Achiatina fulica Férussac), were examined. Of these tripeptides, the following three showed a marked inhibitory effect: L-Glu-L-Phe-L-Tyr (most effective; critical concentration: 3 X 10(-6)--10(-5) M), Gly-L-Phe-L-Tyr and sarcosine-L-Phe-L-Tyr. The TAN inhibition caused by L-Glu-L-Phe-L-Tyr was not due to an increased membrane permeability to chloride ions.     

Fluorescence histochemical methods for the study of peptide hormone-producing cells

Fluorescence histochemical methods for the demonstration of specific residues in peptides and proteins are reviewed: Formaldehyde-ozone for NH2-terminal tryptophan, formaldehyde-HCl for tryptophan regardless of position in the peptide, OPT for NH2-terminal histidine, formaldehyde-fluorescamine for "protected" amino groups, nitroso-naphthol for tyrosine, and phenanthrenequinone for arginine residues. The methods are potent in demonstrating granule-stored material in peptide hormone-producing cells. Also quinacrine, the fluorescent anti-malaria agent, binds to granular components, as yet unidentified, in several endocrine cell types. In many cases the fluorescence histochemical methods seem to demonstrate peptides and proteins distinct from the known hormones.     

Antimicrobial peptides as potential new antifungals

Ribosomally synthesized natural antimicrobial peptides (AP) and their synthetic derivatives are small, cationic, amphipathic molecules of 12-50 amino acids with unusually broad activity spectra. These peptides kill microorganisms by a common mechanism, which involves binding to the lipid bilayer of biological membranes, forming pores, and ultimately followed by cell lysis. Several AP from mammals, amphibians, insects, plants and their synthetic derivatives demonstrate promising in vitro activity against various pathogenic fungi including azole-resistant Candida albicans strains. In addition to their antimicrobial activity, some AP such as lactoferrin, interact with a variety of host cells and can increase the activity of natural killer and lymphokine activated killer cells. Pretreatment of polymorphonuclear neutrophil leukocytes (PMN) or monocytes with these AP also may upregulate superoxide release. AP as potential new antifungal agents offer some advantages, such as rapid killing of pathogenic fungi and the difficulty to raise mutants resistant to these peptides. AP are limited by their nonselective toxicity, stability, immunogenicity and their costs of production. Potential clinical applications of AP in the future have to be further explored in preclinical and clinical studies to assess their impact as a new class of antifungals.     

PAF-acether induced cardiac dysfunction in the isolated perfused guinea pig heart

Summary PAF-acether (1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine) has been implicated in a variety of inflammatory and ischaemic disorders (e.g., myocardial ischemia, anaphylactic shock). Recently, the peptide leukotrienes (i.e., LTC₄, LTD₄) have been shown to mediate the increase in coronary vascular resistance induced by PAF-acether in the isolated perfused rat heart. In isolated perfused guinea pig hearts, PAF-acether produced a dose-dependent increase in coronary perfusion pressure (CPP) and a decrease in contractile force (CF). At 50 mol/l, PAF increased CPP by 13 ± 3 mm Hg and decreased CF by 47 ± 12% in 8 hearts. Radioimmunoassay of the coronary effluent did not detect peptide leukotrienes or thromboxane B₂ (TxB₂) in response to PAF. Addition of a specific PAF-acether receptor antagonist, CV-6209 (25 nmol/l), blocked the increase in coronary perfusion pressure and decrease in contractile force. OKY-1581 (400 nmol/l), a thromboxane synthetase inhibitor or LY-171,883 (7.3 mol/l) a leukotriene D₄ receptor antagonist, failed to prevent the increase in CPP or the decrease in CF. These data indicate that the PAF-acether induced increase in CPP is not mediated by the peptide leukotrienes or thromboxane A₂ (TxA₂). Possible mechanisms for the increase in CPP induced by PAF-acether in the isolated perfused guinea pig heart include a direct receptor mediated constriction of coronary resistance vessels, release of a non-eicosanoid coronary constrictor as a mediator of the response, or via enhancement of coronary microvascular permeability.Supported by Research Grant No. HL-25575 from the National Heart, Lung and Blood Institute of the NIHNIH Predoctoral Trainee (HL-07599)Summer Research Fellow Send offprint requests to A. M. Lefer     

热性惊厥儿童血清脑利钠肽与钠离子水平的临床研究

目的：研究观察热性惊厥患儿血清脑利钠肽(BNP)与钠离子(Na+)水平情况,并分析其临床作用及意义。方法选取2014年4月-2015年10月收治的热性惊厥患儿52例作为研究对象(FC组),另选取同期上呼吸道感染发热但无惊厥患儿50例作为发热对照组(URI组),健康体检儿童50例作为健康对照组(对照组),对比观察各组血清BNP及Na+水平情况。结果 FC组血清BNP水平明显高于URI组及对照组,Na+水平明显低于URI组及对照组,差异有统计学意义(P＜0.05),URI组与对照组两指标水平差异不明显,不具有统计学意义(P＞0.05);血清BNP与Na+水平之间存在负相关关系(P＜0.01)。结论热性惊厥患儿血清BNP水平明显升高、Na+水平明显降低,这可能与BNP分泌对醛固酮系统形成抑制,从而引起血钠降低有关,会进一步促使惊厥发作,因此患儿血清BNP、Na+水平对其病情、治疗及判断预后均有重要的临床意义。     

Active immunizations with peptide-DC vaccines and passive transfer with antibodies protect neutropenic mice against disseminated candidiasis

We previously report that peptide-pulsed dendritic cell (DC) vaccination, which targeting two peptides (Fba and Met6) expressed on the cell surface of Candida albicans, can induce high degree of protection against disseminated candidiasis in immunocompetent mice. Passive transfer of immune sera from the peptide immunized mice or peptide-related monoclonal antibodies demonstrated that protection was medicated by peptide-specific antibodies. In this study the efficacy of active and passive immunization against disseminated candidiasis was tested in mice with cyclophosphamide-induced neutropenia. Peptide-DC vaccines were given to mice prior to induction of neutropenia. We show active immunization with either Fba or Met6 peptide-DC vaccine significantly improved the survival and reduced the fungal burden of disseminated candidiasis in those immunocompromised mice. Importantly, we show that administration of two protective monoclonal antibodies also protect neutropenic mice against the disease, implying possibility of developing a successful passive immunotherapy strategy to treat the disease and protect against disseminated candidiasis. The results of this study are crucial as they address the fundamental questions as to whether the synthetic peptide vaccine induced immunity protects the host during a neutropenic episode. We anticipate that this peptide-vaccine study will serve as the foundation of future investigations into new peptide vaccines comprised of cell surface peptides from other medically important Candida species, as well as other fungi.     

益心舒胶囊联合重组人脑利钠肽治疗慢性充血性心力衰竭的临床研究

目的探讨益心舒胶囊联合重组人脑利钠肽治疗慢性充血性心力衰竭的临床疗效和安全性。方法选取2014年2月—2015年12月延安市人民医院收治的慢性充血性心力衰竭患者112例,随机分为对照组和治疗组,每组各56例,对照组患者静脉滴注冻干重组人脑利钠肽,首次静脉冲击剂量1.5μg/kg,之后以7.5μg/(kg·min-1)的速度静脉滴注。治疗组患者在对照组患者的治疗基础上口服益心舒胶囊,3粒/次,3次/d。两组均连续治疗14 d。观察两组的临床疗效,比较患者左心室收缩末期内径(LVESD)、左室舒张末期内径(LVEDD)、左室内径(LADD)、心指数(CI)、左室射血分数(LVEF)等指标,检测治疗前后去甲肾上腺素(NE)、内皮素-1(ET-1)和抗利尿激素(ADH)指标,并观察两组患者不良反应发生情况。结果治疗后,对照组和治疗组的总有效率分别为78.57%、91.07%,两组比较差异具有统计学意义(P0.05);两组患者LVESD、LVEDD、LADD明显降低,CI和LVEF明显升高,同组治疗前后差异有统计学意义(P0.05);与对照组相比,治疗组患者观察指标改善更明显,差异具有统计学意义(P0.05)。治疗后,两组患者NE、ADH、ET-1水平显著下降,同组治疗前后差异有统计学意义(P0.05);且治疗组患者NE、ADH和ET-1水平改善程度更优于对照组,两组比较差异有统计学意义(P0.05)。结论益心舒胶囊联合重组人脑利钠肽治疗慢性充血性心力衰竭具有较好的临床疗效,安全性高,具有一定的临床推广应用价值。