Complement-fixing properties of pepsin-treated rabbit and sheep antibodies

Rabbit antibody with a sedimentation coefficient of 7S was digested with pepsin to yield the 5S fragment. Washed specific precipitates of 5S antibody and egg albumin, when added to guinea pig serum, fixed up to 40 percent of the total complement. This fixation could not be attributed to contamination with 7S antibody. Absorption of guinea pig serum with washed precipitates of 5S antibody and antigen removed that portion of complement which was fixed by fresh 5S antibody-antigen aggregates, but not that fixed by 7S antibody-antigen aggregates. The presence of 0.001M ethylenediaminetetraacetic acid prevented this absorption of complement by the 5S aggregates.     

Passive cutaneous anaphylaxis with antibody fragments

Pepsin-digested rabbit antibody (5S) provoked reverse passive cutaneous anaphylaxis in the guinea pig, but was somewhat less effective, mole for mole, than the native antibody. Fixation of guinea pig complement by the pepsin-digested antibody could not be demonstrated either in vitro or in vivo. Splitting of the 5S fragment into two monovalent fragments (3.5S) markedly reduced the capacity to provoke reverse passive cutaneous anaphylaxis.     

Immunoglobulin M: fixation of human complement by the Fc fragment

The Fc fragment [(Fc)(5)micro with a molecular weight of 342,000] of human immunoglobulin M from patients with Waldenstr?m's macroglobulinemia has a complement fixing ability approximately 19 times greater on a molar basis than that of the parent immunoglobulin M. This fragment, which occurs naturally as a pentamer fixes human but not guinea pig complement, and this activity remains unchanged even after the fragment is reduced to the monomeric form.     

Anaphylatoxin in its relation to the complement system

The fifth component of complement that reacts hemolytically in the guinea pig or rat complement system, C'3b, is intimately associated with the generation of anaphylatoxin. Anaphylatoxin was formed (i) if this purified component reacted with a washed, intermediate complex consisting of antigen, antibody, and the first four components of complement; (ii) if the component was treated with trypsin; or (iii) if the component was incubated with a material isolated from cobra venom together with a fraction from serum other than complement. The significance of this fifth component as anaphylatoxinogen is discussed, and a common mechanism is proposed for the generation of anaphylatoxin in whole serum.     

Guinea pig complement: two active forms of first component

By solubility chromatography at pH 7.5 and low ionic strength, a partially purified preparation of the first component of guinea pig complement was separated into two fractions of different solubility under these conditions. On rechromatography, each fraction emerged in the same position as it had originally.     

Genetic defect in biosynthesis of the precursor form of the fourth component of complement

Under cell-free conditions, liver polysomes from guinea pigs genetically deficient in the fourth component of complement (C4) did not synthesize pro-C4 (the precursor of C4), but did synthesize nascent C4 polypeptides which remained polysome bound. The defect was specific for pro-C4 synthesis since the amounts of total protein and albumin synthesis and release from C4-deficient polysomes were similar to that in normal guinea pig liver polysomes.     

Localization of calcium pump activity in smooth muscle

A microsomal fraction isolated from longitudinal smooth muscle of guinea pig ileum actively sequesters calcium ion in the presence of magnesium and adenosine triphosphate in a fashion previously described for microsomes of the rabbit aorta. This activity in guinea pig ileum appears to be associated primarily with the plasma membrane as is found in the red cell. By contrast the uptake of calcium in aortic smooth muscle appears to be associated to an appreciable extent with intracellular membranes, possibly analogous to the sarcoplasmic reticulum of skeletal muscle.     

Anaphylatoxin release from the third component of human complement by hydroxylamine

Treatment of highly purified preparations of the third component of complement (C3) with 0.5M hydroxylamine at 20 degrees C for 15 to 30 minutes, followed by acidification, resulted in dissociation of a peptide from the C3 molecule. The isolated fragment (molecular weight, 7600) resembled enzymatically liberated anaphylatoxin (C3a) with respect to size, charge, amino acid composition, and biological activity. Its capacity to contract smooth muscle was inhibitable by antihistamines; it also produced tachyphylaxis and desensitization of the guinea pig ileum to C3a. Thus native C3 probably contains an esterlike bond and hydroxylamine-liberated anaphylatoxin may represent one of the polypeptide chains of the C3 molecule.     

Coronary vasoconstrictor effects of atriopeptin II

Atrial natriuretic peptides lower arterial pressure, cardiac filling pressure, and cardiac output. In isolated, Langendorff-perfused guinea pig hearts, atriopeptin II, the 23-amino acid atrial natriuretic peptide, is also a potent coronary vasoconstrictor. The median effective dose for atriopeptin II in guinea pig hearts is 26 nanomoles, the threshold constrictor dose is 5 nanomoles, and flow nearly ceases at a dose of 100 nanomoles in perfused hearts at constant pressure. Similar concentrations of atriopeptin II also cause coronary vasoconstriction in rat and dog heart preparations. The disulfide bridge is necessary for vasoconstrictor activity; reduction of this bridge abolishes the activity, as it does the other biological activities of atrial natriuretic peptides.     

Efficiency of the first component of complement (C'1) in the hemolytic reaction

With the use of the first component of guinea pig complement (C'1) labeled in vivo with (14)C-amino acids, we have obtained evidence that, under the conditions required for the assay of C'1, each molecule of C'1 capable of interaction with cell surface antigen-antibody complexes is capable of initiating the reaction sequence that leads to lysis of the cell.     

Soluble membrane antigens of lip and cervical carcinomas: reactivity with antibody for herpesvirus nonvirion antigens

With the use of antibody for herpesvirus nonvirion antigens (not structural components of the virus) complement fixing reactivity has been shown for soluble membrane antigens separated from lip and cervical carcinomas but not for similar extracts from normal vaginal tissue or intestinal carcinoma. Neither the serum obtained from the guinea pig before hyperimmunization with the herpesvirus nonvirion antigen nor the antiserum of guinea pigs immunized with comparable uninfected cell extracts reacted with these tumor soluble membrane antigens. Since the above soluble membrane antigens could be specific markers for the presence of virus genome within the tumor cells, the findings could support an etiological role of herpesvirus in selected human malignancies.     

宠物豚鼠隐孢子虫感染情况调查及其虫种鉴定

为了解宠物豚鼠隐孢子虫感染情况,用饱和蔗糖溶液漂浮法对郑州某宠物市场55份豚鼠粪便和免疫抑制后的30只豚鼠新鲜粪便样本进行检查。结果发现,隐孢子虫总感染率分别为12.7%和80%,卵囊呈近圆形,卵囊大小为5.3μm×4.7μm〔(5.0～5.5)μm×(4.4～4.9)μm〕,卵囊指数为1.11。基于18SrRNA基因位点,对调查中发现的7个隐孢子虫分离株进行PCR扩增,PCR-RFLP和测序结果显示,7个分离株均为维瑞隐孢子虫。宠物豚鼠隐孢子虫感染较为普遍,感染虫种是维瑞隐孢子虫,且豚鼠在免疫抑制后,其隐孢子虫感染率显著增高。     

Deficient complement fixation by aggregated gamma globulin from hypogammaglobulinemic patients

We found that several normal samples of aggregated gamma globulin consistently fixed essentially equal amounts of guinea pig complement, while samples of gamma globulin from three of four hypogammaglobulinemic patients were markedly deficient in this biologic function. Thus, the previously observed limited heterogeneity of gamma globulin in patients with hypogammaglobulinemia is also associated with inefficiency in at least one biological function.     

Australia antigen (hepatitis B antigen): a conformational antigen dependent on disulfide bonds

Reduction and alkylation of purified hepatitis-associated Australia antigen (hepatitis B antigen) resulted in a total loss of serologic activity. The reduced and alkylated protein formed a single band with a sedimentation coefficient of 31S on analytical ultracentrifugation, and no subunits were detected by Sephadex gel filtration. Although this preparation induced a delayed hypersensitivity response when injected into guinea pigs, it failed to stimulate humoral antibody formation. The data suggest that hepatitis B antigen is a conformational antigen critically dependent upon the disulfide bonds of the protein moiety.     

Tumor cells secrete a vascular permeability factor that promotes accumulation of ascites fluid

Tumor ascites fluids from guinea pigs, hamsters, and mice contain activity that rapidly increases microvascular permeability. Similar activity is also secreted by these tumor cells and a variety of other tumor cell lines in vitro. The permeability-increasing activity purified from either the culture medium or ascites fluid of one tumor, the guinea pig line 10 hepatocarcinoma, is a 34,000- to 42,000-dalton protein distinct from other known permeability factors.     

Hemolysin production in the development of staphylococcal lesions

The presence of hemolysin in staphylococcal lesions of the rabbit kidney was detected by overlaying sections of kidney with blood agar. Hemolytic activity against rabbit, human, sheep, calf, and guinea pig erythrocytes was present and was not abolished by heating the sections to 60 degrees C for 30 minutes. In developing lesions, hemolytic activity appeared before necrosis or exudation.     

Antagonism of purified asparaginase from guinea pig serum toward lymphoma

The tumor inhibitory activity of highly purified asparaginase from guinea pig serum toward the Gardner lymphosarcoma in C3H mice was compared with that of the serum itself. The purified enzyme, homogeneous by ultracentrifugation and immunoelectrophoresis, had activity comparable to that of the serum. The serum was also effective in mice which were made immunologically incompetent by radiation with coba't-60.     

食用豚鼠肉营养价值分析

测定了食用豚鼠肉各营养成份的含量。结果表明:豚鼠肉胴体率为66.5%,净肉率为48.3%。每100g豚鼠肉含有水份75.1%,粗蛋白18.3%,粗脂肪1.8%,灰分0.9%。每100g豚鼠肉18种氨基酸的含量在0.14~3.73g之间,氨基酸总量、必需氨基酸总量、必需氨基酸占氨基酸总量比例、鲜味氨基酸含量及鲜味氨基酸占氨基酸总量比例分别为18.27g、6.94g、37.99%、5.29g和28.95%。每1kg豚鼠肉中钙、铁、锌和硒的含量分别为1 208mg、10mg、16mg和0.15mg。     

Spatially resolved calcium dynamics of mammalian Purkinje cells in cerebellar slice

Microfluorometric imaging was used to study the correlation of intracellular calcium concentration with voltage-dependent electrical activity in guinea pig cerebellar Purkinje cells. The spatiotemporal dynamics of intracellular calcium concentration are demonstrated during spontaneous and evoked activity. The results are in agreement with hypotheses of dendritic segregation of calcium conductances suggested by electrophysiological experiments. These in vitro slice fluorescence imaging methods are applicable to a wide range of problems in central nervous system biochemical and electrophysiological functions.     

ACETYLCHOLINE-LIKE ACTIVITY IN SCIATIC NERVE

Extracts of sciatic nerve exhibit acetylcholine-like activity that is only partly attributable to acetylcholine. The extracts show relatively greater activity on the rectus abdominis muscle of the frog than on the ileum of the guinea pig. To prevent the action of the extract on the frog rectus abdominis muscle, a greater concentration of d-tubocurarine is required than is necessary to prevent the action of known acetylcholine.