Fever response of sheep in the peripartum period to Gram-negative and Gram-positive pyrogens

We have measured body temperatures and serum iron concentrations of sheep in the peripartum period following administration of endotoxin and Staphylococcus aureus cell walls. Both the rise in rectal temperature and the fall in serum iron concentration following intravenous injection of S. aureus were the same immediately pre- and postpartum as they were 5 weeks after parturition. The rise in rectal temperature following intravenous endotoxin injection immediately pre- and postpartum was significantly less than that of the same ewes 5 weeks later. However, the fall in serum iron concentration following endotoxin injection was significantly suppressed only prepartum. We conclude that fever is not suppressed in sheep in the peripartum period, but the response to endotoxin is suppressed, through complex processes incidental to the mechanisms responsible for the maintenance of gestation and induction of labour.     

柴胡注射液对家兔内生致热原性发热及其脑脊液cAMP含量变化的效应

本实验共分二部分进行。第一部分,观察柴胡注射液解热效应,第二部分,观察柴胡注射液解热时对脑脊液cAMP含量变化的影响。用家兔内生致热原复制发热模型,剂量(1×10~6 cells/ml)0.5ml/kg。目前认为:cAMP是一种重要的中枢性发热介质,脑脊液中cAMP含量与发热效应呈正相关。本研究结果表明,柴胡注射液(250mg/kg)对内生致热原性发热有明显抑制作用;同时,脑脊液中cAMP含量也明显低于发热对照组。作者推论:柴胡注射液可能通过某些环节减少体温调节中枢神经元cAMP合成和释放,从而抑制发热效应。     

不同浓度内生致热原的发热效应,脑脊液中cAMP的反应及“热限”的研究

为研究cAMP在发热机制及“EP热限”中的作用,用家兔血细胞加微量内毒素体外培育制备内生致热原(EP),在72只家兔的实验中观察不同剂量EP静脉注射后4小时发热效应;在65只家兔的实验中观察不同剂量EP静脉注射后1小时发热效应及血浆和脑脊液中cAMP含量变化。实验结果表明:(1) 在一定范围内,EP的发热效应随注射剂量的递增而增强,但当发热达到一定强度后,便不再随EP剂量的继续增加而加强,在剂量—效应曲线上出现“平坡”,作者称之为“EP热限”。(2)注射EP后1小时,血浆中cAMP无明显变化,而脑脊液中cAMP的浓度却明显增加,且与发热效应呈非常显著的正相关关系。(3) 当注射大剂量EP出现“热限”时,脑脊液中cAMP的增长也受限。作者推论:脑脊液中cAMP的变化不是来自血浆,cAMP很可能是EP发热的重要中枢介质,cAMP的增长受限可能是“EP热限”的重要成因。     

Effect of cytostatic agents on development of the febrile reaction to injection of bacterial pyrogen

The development of the febrile reaction to injection of bacterial lipopolysaccharide (pyrogenal) in rabbits after preliminary treatment with actinomycin D and cortisone was studied. This treatment did not change the reactivity of the temperature regulating centers of the rabbits to endogenous pyrogen. After intravenous injection of the bacterial pyrogen the febrile reaction, was considerably shortened, and after intracisternal injection of the pyrogen the reaction was sharply inhibited. These results indicate an important role of polymorphonuclear leukocytes and of endogenous pyrogen formation by these cells in the mechanism of fever in response to the action of bacterial pyrogen.Department of General Pathology, Institute of Experimental Medicine, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR P. N. Veselkin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 11, pp. 1314–1317, November, 1976.     

Fever response induced by intravenous and intracerebroventricular injection of pyrogen in thyroidectomised and protein-calorie malnourished rabbits

The development of a fever in response to intravenous (IV, 1.5 g/kg body mass) and intracerebroventricular (ICV, 1.5 g/animal) injections of Escherichia coli lipopolysaccharide (LPS) was studied in control, thyroidectomised and protein-calorie malnourished rabbits (New Zealand Whites, n=55). ICV injection of LPS in control rabbits produced a fever response, the characteristics of which differed from those obtained after IV pyrogen injection. Thyroid deficiency caused an attenuated fever response, irrespective of whether LPS had been administered by IV or ICV injection. Protein-calorie malnourished rabbits showed a smaller fever response after IV or ICV pyrogen injections. Malnourished rabbits, refed over a period of 15 days, showed a typical biphasic fever response, but with lower magnitude than controls. The results of these experiments suggest that ICV injection of LPS is not an appropriate model for the study of fever mechanisms in disease states, and that the attenuated fever response observed in proteincalorie malnourished rabbits may be related, at least in part, to a decreased ability to produce the endogenous pyrogen interleukin-1.     

新生SD大鼠血常规各项与发育时间的相关性分析及其与血清铁浓度变化的机制

 目的：探讨经心脏穿刺和剪尾2种采血方式对新生SD大鼠血常规的影响;建立其血常规正常参考值范围;研究发育过程中血常规各项、血细胞形态和血清铁（SI）的消长变化及其相互关系,揭示SI变化的可能机理。方法：新生鼠出生后1、2、3、7和14 d,经全自动血液分析仪检测心脏血和鼠尾血中红细胞(RBC)计数、血红蛋白(HGB)含量、血小板(PLT)计数和白细胞(WBC)计数的改变;通过瑞氏-姬姆萨染色观察2种血液中血细胞形态的差别,及其在不同发育阶段的变化情况;选择心脏穿刺采血建立血常规正常值参考范围;经血液生化分析仪检测各时点心脏血SI含量变化;统计学分析发育时间、血常规各项及SI含量三者间的动态关系。结果：鼠尾血中RBC计数、HGB含量和WBC计数均高于心脏血,且RBC碎片较多;RBC形态随发育逐渐成熟稳定,其碎片亦明显减少;发育时间与心脏血中RBC和PLT计数呈正相关(P<0.01),与HGB含量、红细胞压积(HCT)、红细胞平均体积(MCV)、平均血红蛋白量(MCH)、平均血红蛋白浓度(MCHC)、WBC计数和SI含量呈负相关(P<0.01)。SI含量与RBC计数呈负相关(P<0.05),与MCV(P<0.01)和MCH(P<0.05)则呈显著正相关。结论：经心脏采血能建立相对完善的正常新生SD大鼠血常规参考值范围;新生鼠血常规各项与发育时间存在显著相关性;发育早期RBC的不稳定性可能是导致SI含量在发育早期较高的原因。     

柴葛解肌汤对家兔白细胞致热原性发热效应及脑脊液cAMP含量的影响

本研究选用65只新西兰白兔,观察经口灌入柴葛解肌汤(柴葛汤)对家兔白细胞致热原(LP)性发热效应及脑脊液cAMP含量的影响。结果表明:(1)柴葛汤经口灌入对家兔正常体温没有明显影响(P>0.05)。(2)单独静脉注射LP组,体温上升0.93±0.07℃,静注LP前1小时经灌口注柴葛汤,体温上升仅0.29±0.07℃,两组均数比较有非常显著的差异(p<0.01),说明柴葛汤具有明显的解热作用。(3)静注LP 1小时(LP性发热高峰期),脑脊液cAMP含量为141.18±23.04pmol/ml,静注LP前1小时经口灌入柴葛汤,脑脊液cAMP含量为94.37±6.20pmol/ml,两者比较有显著差异(P<0.05)。相关检验表明,柴葛汤 LP组的体温上升高度与脑脊液cAMP含量变化呈明显正相关。表明柴葛汤不仅抑制LP引起的发热反应,而且明显低降LP引起的脑脊液cAMP含量增多。根据这些实验绪果,作者推论,柴葛汤可能是通过降低脑内上升的cAMP含量而导致解热效应的。     

Development and design of a novel in vivo chamber implant for the analysis of microbial virulence and assessment of antimicrobial therapy

An accurate reflection of the pathogenicity of microorganisms and the therapeutic effects of antimicrobial agents on their growth necessitates testing within an in vivo environment. We have developed a novel diffusion chamber, incorporating two 0.22 μm membrane filters, for the growth of in vivo organisms. The chamber, which is implanted intraperitoneally into the rat, has an external sampling portal. This portal allows multiple and sequential sampling of the microbial inoculum without killing the rat, thus significantly reducing the total number of animals used in such studies. In addition, the chamber is superior to other reported implants since it is well tolerated, reusable, easily constructed and can be used within two days of implantation. Staphylococcus epidermidis and a toxic shock syndrome toxin-1 (TSST-1) producing strain of S. aureus have been successfully grown within in vivo chambers, with 10⁸–10⁹ organisms per millilitre being recovered within 48 h. Scanning electron microscopy revealed clusters of staphylococci and fibrous material adhering to the inner surface of the filters, with numerous phagocytic cells attached to the outer side. Western immunoblotting indicated that higher levels of TSST-1 were produced by S. aureus grown in vivo as opposed to cells grown in vitro.     

黄连注射液对家兔白细胞致热原性发热和脑脊液中cAMP含量变化的影响

本研究用兔78只,分两部分进行实验。第一部分,观察黄连注射液对家兔白细胞致热原(1eucocytic pyrogen;LP)性发热的降热效应;39只兔分成四组;Ⅰ为LP组;Ⅱ为黄连 LP组;Ⅲ为黄连组,Ⅳ为对照组。Ⅰ组9只兔,Ⅱ～Ⅳ组各10只兔。第二部分,观察黄连注射液对发热家兔脑脊液中cAMP含量变化的影响。动物数与分组同第一部分。结果表明,LP 黄连组60分钟△T℃(0.70±0.12),TRI_4(3.37±0.07)明显低于LP组△T℃(1.11 0.11)、TRI_4(5.56±0.10),分别比较两组△T℃、TRI_4,其差异性均非常显著(P<0.01)。上述两组动物60分钟脑脊液中cAMP含量分别为0.76±0.08和1.29±0.13,统计学处理后差异性非常显著(P<0.01)。黄连组动物60分钟△T℃(0.04±0.10)与对照组△T℃(0.03±0.06)相比较,无统计学意义(P>0.05)。作者推论:黄连注射液降热作用的机制,很可能与抑制POAH区神经元cAMP的生成有关。     

Influenza a outbreak among adolescents in a ski hostel

An outbreak of influenza A H3N2 with a high attack rate (49%) and abrupt onset (69% became ill within 2 days) occurred among 81 ski school participants who stayed in a crowded hostel in Austria in early 1997. Two students were hospitalized with pneumonia; one of them died. Cultures of blood and/or respiratory secretions from the hospitalized students yielded toxin-producingStaphylococcus aureus. Influenza A H3N2 was confirmed serologically in four participants, including one surviving hospitalized student, and by polymerase chain reaction of lung tissue from the deceased student. This investigation demonstrates that influenza can cause an explosive outbreak among skiers in a crowded hostel, leading to severe complications among previously healthy adolescents.     

Response of Haemophilus somnus to iron limitation: expression and identification of a bovine-specific transferrin receptor

Nine clinical isolates of Haemophilus somnus were screened for their ability to use different transferrins as a source of iron growth. All nine strains were capable of using bovine but not porcine, human or chicken transferrin. A screening assay for siderophore production did not show any evidence of siderophore production by these strains. When iron-deficient cells from these strains were screened for their ability to bind perixodase-conjugated transferrin, binding was detected with conjugated bovine, but not human or porcine transferrin. Competition binding studies demonstrated that the binding of peroxidase-conjugated bovine transferrin was competitively inhibited by unconjugated bovine transferrin but not transferrin from other species. The induction of receptor expression by low iron conditions was inhibited by chloramphenicol and rifampicin but not ampicillin indicating that new protein and mRNA synthesis was required for expression of receptor activity. Affinity isolation of receptor proteins with biotinylated bovine transferrin, but not human or porcine transferrin, yielded three proteins from H. somnus strain H74. Two of the proteins were identified as 105 kDa and 73 kDa iron-regulated outer membrane proteins. A third protein of 85 kDa that was isolated did not co-migrate with any iron-regulated outer membrane protein. Affinity isolation of receptor proteins from other strains of H. somnus yielded a 73 kDa protein from all strains and a 105 kDa and 85 kDa protein in four of the six strains analysed.     

Alterations in serum and tissue iron profiles associated with mutations in the fitness1 4226sb locus of mice

We investigated alterations in serum and tissue iron profiles that were associated with anN-ethyl-N-nitrosourea-induced mutation in thefitness 1 locus in chromosome 7 in mice. Mice hemizygous for thefitness 1 mutation [c fitness 1 ^4226SB/Df(c Mod2 shl)^26DVT] had a microcytic, hypochromic anaemia which was associated with a lower concentration of iron in the serum compared to age-matched, control mice [c ^ch+/c^ch+]. The hemizygous mutants had a greater total iron binding capacity and an increased unsaturated iron binding capacity compared to controls. The percentage transferrin saturation was significantly decreased in the hemizygous mutant mice compared to control mice. The concentration of iron within several body organs was determined and hemizygous mutant mice had a greater concentration of iron in the liver compared to controls. In contrast, the mutants had a lower concentration of iron within the spleen, kidneys and heart compared to control mice. Microscopic analysis of bone marrow smears indicated less iron in the smears from the hemizygous mutants. From these data, it was concluded that thefitness1 ^4226SB mutation in mice causes alterations in the serum iron profile that resemble iron deficiency. The alterations in tissue iron concentrations indicate an abnormal distribution or mobilisation of iron between organ systems. The exact mechanism(s) by which thefitness1 ^4226SB mutation mediates these abnormalities in iron distribution remains to be determined.     

家兔不同发热反应的体温功率谱分析

本研究对不同热型的发热体温信号作功率谱分析,发现各具时域特征的多种发热在频域中表现为相当一致的统一性,即它们的功率谱均为低频段的单一谱峰,其幅值大小与发热反应强弱成正比。功率谱密度值与时域指标体温反应指数(TRI)有极好的相关性。     

Lymphatic mast cell response and effect of compound 48/80 on popliteal lymph node reaction in rats following intracutaneous injection ofStaphylococcus aureus

To investigate the significance of mast cells in the popliteal lymph node during the development of an inflammatory response, rats were inoculated with 12×10⁷ colony-forming units ofStaphylococcus aureus in the hind foot pad. Numerical changes in mast cells were then measured in the corresponding popliteal lymph node. Six days after inoculation, despite the enlargement of the responding lymph node, a marked decrease in granulated mast cell number, relative to the contralateral node, was observed in the cortical and medullary compartments. Popliteal lymph nodes from rats treated with compound 48/80 and then inoculated withS. aureus showed a higher cortical and medullary hypertrophic response and a significant increase in degranulated/weakly basophilic mast cell number in the lymph node tissue. The findings suggest that (1)Staphylococcus aureus induces a reduction in granulated mast cell number in the cortical and medullary compartments of regional lymph nodes; (2) pretreatment with compound 48/80 appears to contribute to the lymphoid cell proliferation and the hypertrophic response of lymph nodes induced byS. aureus; and (3) granulated mast cells have a regulatory role on lymphoid cell proliferation.     

Staphylococcal Presence Alters Thrombus Formation Under Physiological Shear Conditions in Whole Blood Studies

The ability of platelets to aggregate at a site of injury and form a thrombus is central to normal hemostasis and host survival. Staphylococcus aureus is a major pathogenic organism that has been described as interacting with platelets and promoting platelet aggregation. However, the fundamental effects of bacterial presence on thrombus formation are poorly understood. In this study, we quantify thrombus formation in whole blood in the presence and absence of S. aureus under physiological shear conditions. Using confocal microscopy we observed that S. aureus causes a reduction in thrombus volumes and alters the morphological structure of the growing thrombi.     

Role of insertion elements and yycFG in the development of decreased susceptibility to vancomycin in Staphylococcus aureus

The glycopeptide antibiotic vancomycin acts by binding to the D-alanyl-D-alanine terminus of the cell wall precursor lipid II in the cytoplasmic membrane. The purpose of this study was the identification of genes that might be involved in the vancomycin resistance mechanism. To this end, the expression profiles of two vancomycin intermediately resistant Staphylococcus aureus (VISA) strains, the clinical isolate S. aureus SA137/93A (Etest: 8 microg/ml) and its laboratory mutant S. aureus SA137/93G (Etest: 12 microg/ml) were analyzed using an S. aureus full-genome chip. The results indicated that an essential two-component regulatory system, yycF (vicR) and yycG (vicK) was drastically up-regulated in strain SA137/93A. Sequencing of the yycFG promoter region of strain SA137/93A revealed an insertion of IS256 in the predicted promoter region creating a potentially stronger hybrid promoter. In strain SA137/93G, IS256 was not integrated in the yycFG promoter region but, in previous studies, a copy of IS256 had been found to inactivate the tcaA gene (Maki et al. Antimicrob. Agents and Chemother. 48, 1953-1959 (2004)). Detailed population analyses showed that, in addition to the loss of SCCmec, the inactivation of tcaA seems to cause at least part of the increase in teicoplanin and vancomycin resistance in strain SA137/93G.     

Binding of a Staphylococcus aureus bone pathogen to type I collagen

We contrasted the collagen-binding potential of the experimental osteomyelitis pathogen, Staphylococcus aureus strain SMH, to several other strains. These included Cowan 1 (binder), Wood 46 (non-binder) and six capsular variants. These measurements were made using an ¹²⁵I-collagen binding assay. Formalin-killed S. aureus SMH strongly bound commercial type I iodinated collagen (dissociation contant, K_d = 2 × 10⁻⁹ m). The extent of binding was similar to Cowan 1. Binding was saturable and not inhibited by 100 m solutions of -glucose, -galactose, -mannose, methyl-α- -fucopyranoside, -hydroxyproline or -glycine. -lactose gave moderate inhibition of binding to collagen, and -fucose was strongly inhibitory. Trypsinized SMH did not bind collagen. None of four Ruthenium-red-staining staphylococci (encapsulated) avidly bound type I collagen. The encapsulated Smith strain, for example, did not bind to collagen but its capsule-negative variant, Smith compact, showed extensive binding. Three of five non-encapsulated S. aureus were strong collagen binders. These data suggest that the prototype bone pathogen binds to the major protein component of bone's extracellular matrix. Collagen-binding is promoted by protein adhesin(s), not capsule. The latter, in fact, appeared to interfere with this interaction. Binding was inhibited by solutions containing the simple monosaccharide, -fucose.