Antigen-induced histamine release from guinea pig basophils

Guinea pig blood was found to contain an average of 106 +/- 21 ng/ml of histamine. Of this total, approximately 85-90% was of platelet origin and the rest from basophils. Basophils contain about 0.72 pg of histamine/cell. Concanavalin A (1-5 microgram/ml) induced the release of approximately 65% of the basophilic histamine. When basophils were isolated from animals sensitized to ovalbumin or keyhole limpet hemocyanin, addition of the appropriate antigen induced histamine release at concentrations of 0.01 microgram/ml or lower. Individual animals were studied over time by repetitive bleeding. The circulating basophils remained sensitized for at least 17 weeks postsensitization. However, release did not occur if animals had been sensitized less than 7 days earlier. This assay facilitates the investigation of basophil sensitization since animals can be studied on several occasions following immunization. The mechanisms, timing and role of basophil sensitization in various types of immune and hypersensitivity reactions can now be evaluated.     

Caspase-3 activation in the guinea pig cochlea exposed to salicylate

In the current study, we explored whether chronic salicylate exposure could induce apoptosis in outer hair cells (OHCs) and spiral ganglion neurons (SGNs) of the cochlea. Guinea pig received sodium salicylate (400 mg/kg/d) or saline vehicle for 10 consecutive days. Programmed cell death (PCD) executioner was evaluated with immunohistochemistry detection of activated caspase-3. Apoptosis was examined with a terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) method. Repeated salicylate administration activated caspase-3 and caused apoptosis in OHCs and SGNs (p < 0.01 vs. saline control for both measures and in both cell types). Cell counting showed a significant loss in OHCs (p < 0.01 vs. saline control), but not in inner hair cells (IHCs). Transmission electron microscopy (TEM) revealed chromatin condensation and nucleus margination in salicylate-treated cochlea. Scanning electron microscopy (SEM) demonstrated stereociliary bundles breakdown and fusion at the apical of OHCs, villous matter was discovered to attach on the surface of SGNs. These findings suggest that long-term administration of high-dose salicylate can activate caspase-3 pathway to induce OHC and SGN apoptosis.     

The permeability of the guinea pig parietal yolk sac placenta to peroxidase and ferritin

The permeability of the guinea pig parietal yolk sac placenta late in gestation was investigated by means of electron microscopy using the tracer proteins ferritin and peroxidase. The parietal yolk sac consists of a layer of trophoblast, a thick extracellular lamina (Reichert's membrane) and a layer of endoderm. After injection into the maternal vascular system, the proteins crossed the trophoblast by means of small pinocytotic vesicles. Both proteins readily permeated Reichert's membrane and then moved by an intercellular pathway between endoderm cells to reach the uterine lumen. After injection of ferritin into the uterine lumen, the protein was observed between endoderm cells and throughout Reichert's membrane. Presumably the marked permeability of the endodermal epithelium to the tracer molecules is due to the absence of zonulae occludentes around the endoderm cells. Parietal endoderm cells exhibited limited pinocytotic activity regardless of the site of injection. The results indicate that the parietal yolk sac placenta of the guinea pig is permeable to relatively large molecules and therefore it may be an important pathway in overall maternal-fetal exchange in this species.     

Granulocyte recruitment in guinea pig lungs following the administration of MBP-like cationic protein

Inflammation Research -     

Down-regulation by cannabinoids of the immunological activation of human basophils and guinea pig mast cells

Inflammation Research -     

Simulations to derive membrane resistivity in three phenotypes of guinea pig sympathetic postganglionic neuron

The electrotonic behavior of three phenotypes of sympathetic postganglionic neuron has been analyzed to assess whether their distinct cell input capacitances simply reflect differences in morphology. Because the distribution of membrane properties over the soma and dendrites is unknown, compartmental models incorporating cell morphology were used to simulate hyperpolarizing responses to small current steps. Neurons were classified as phasic (Ph), tonic (T), or long-afterhyperpolarizing (LAH) by their discharge pattern to threshold depolarizing current steps and filled with biocytin to determine their morphology. Responses were simulated in models with the average morphology of each cell class using the program NEURON. Specific membrane resistivity, R(m), was derived in each model. Fits were acceptable when specific membrane capacitance, C(m), and specific resistivity of the axoplasm, R(i,) were varied within realistic limits and when underestimation of membrane area due to surface irregularities was accounted for. In all models with uniform R(m), solutions for R(m) that were the same for all classes could not be found unless C(m) or R(i) were different for each class, which seems unrealistic. Incorporation of a small somatic shunt conductance yielded values for R(m) for each class close to those derived assuming isopotentiality (R(m) approximately 40, 27, and 15 k omega cm(2) for T, Ph, and LAH neurons, respectively). It is concluded that R(m) is distinct between neuron classes. Because Ph and LAH neurons relay selected preganglionic inputs directly, R(m) generally affects function only in T neurons that integrate multiple subthreshold inputs and are modulated by peptidergic transmitters.     

碱性铁蛋白对肾小球基膜及系膜区通透性的影响

目的为探讨碱性铁蛋白（ＣＦ）注射后，对肾基膜（ＧＢＭ）及系膜区通透性的影响。方法用带有阳性电荷的ＣＦ，按５０ｍｇ／ｋｇ的量一次性由静脉注入大白鼠体内。取肾组织经聚乙烯亚胺（ｐｏｌｙｅｔｈｙｌｅｎｉｍｉｎｅ，ＰＥＩ）特殊染色，在电子显微镜下观察。结果基膜的ＰＥＴ颗粒数量显著改变（Ｐ＜０．０５），而系膜基质的ＰＥＩ却无变化（Ｐ＞０．０５）。结论基膜的负电荷起着电荷屏障作用，与蛋白尿的产生有关；而基质区域则是淋巴通路，与蛋白尿的形成无关。     

Development of membrane differentiations in the guinea pig spermatid during spermiogenesis

We have studied the development of membrane differentiations in guinea pig spermatids during spermiogenesis, using electron microscopy of thin sections, freeze-fracturing, and filipin labeling as an indicator of membrane cholesterol distribution. The development of the distinctive membrane specializations closely correlated with the developmental steps of spermatid differentiation. The annulus, the zipper, and the circumferential strands of particles overlying the mitochondrial gyres of the midpiece appeared in the plasma membrane over the tail during the last two steps of spermiogenesis. The outer acrosomal membrane showed trnsient crenations during the acrosome phase and serrations over the equatorial segment of the acrosome during the maturation phase. On the inner nuclear membrane, a depression appeared opposite the inner zone of the acrosome during the Golgi phase and persisted throughout spermiogenesis. The implantation fossa also appeared during this phase, as a bulging on the inner nuclear envelope covered with small membrane particles. By the cap phase, small and large 15–20-nm particles were present at the implantation-fossa site, and clusters of 9-nm particles were seen over the postacrosomal segment of the nuclear envelope. The migration of the nuclear pores began when close contacts were established between adjacent nuclear membranes. It started simultaneously at the anterior pole and the implantation fossa and later progressed over the segment of membrane between the caudal margin of the acrosome and the posterior ring. By the maturation phase, the nuclear pores had migrated to the redundant nuclear envelope. After filipin labeling, a gradient was visible in the distribution of the cholesterol-filipin complexes, decreasing from the plasma membrane to the nuclear membrane. Within the same membrane, cholesterol distribution varied from one pole of the cell to the other. On the differentiations of the plasma membrane over the tail, cholesterol-filipin complexes were absent, but they were profuse in the membrane over the head. In the acrosomal membrane, the complexes were gathered in clumps associated with the crenations. They became fewer in the rostral segment but remained moderate in the caudal equatorial segment as spermiogenesis proceeded. The nuclear membrane contained cholesterol-free regions opposite the inner acrosome and at the site of the implantation fossa. Otherwise, the acrosomal segment of the nuclear envelope demonstrated a homogeneous distribution of cholesterol-filipin complexes, while the postacrosomal segment showed small clumps of complexes adjacent to nuclear pores. We propose that each of the spermatid cell membranes is not an autonomous system, but is dependent upon its exchanges with the immediate external environment under the one side of the membrane and its close coupling to the internal environment (i.e., membrane-associated structures: annulus, zipper, etc.) under the otehr side of the membrane. We suggest that the cholesterol in spermatid cell membranes contributes to the establishment of their mosaicism and regulates the modeling of the spermatid by modulating the internal fluidity of individual membrane segments during spermiogenesis.     

Ultrastructural localization of anionic and cationic ferritin in the rat glomerular basement membrane in protein-overload proteinuria

The penetration into the glomerular basement membrane of anionic and cationic ferritin has been studied in rats made proteinuric by intraperitoneal administration of bovine serum albumin. In comparison with control animals anionic ferritin penetrated the glomerular basement membrane to a much greater extent in proteinuric rats. Some ferritin particles were observed in small invaginations of the epithelial cell membrane adjacent to the glomerular basement membrane and incorporated in pinocytotic vesicles within the epithelial cell cytoplasm. This was not seen in control animals. Cationic ferritin distribution in the glomerular basement membrane was similar in control and proteinuric rats suggesting that the increased anionic ferritin penetration observed occurs without any reduction in fixed anionic charge.     

Development of membrane potentials of cortical cell elements in guinea pig fetus

The mean membrane potentials of cellular elements were measured during the passage of a glass microelectrode through cortical tissue in fetuses and newborn guinea pigs. The average value of membrane potential increases in fetuses after the 47th day of gestation from 7.6 mV to 28.1 mV in newborn guinea pigs. The developmental changes in histograms of individual values correspond to the increase in mean value. The membrane potentials are sensitive to brain hypoxia following cord clamping only after the 62nd day of gestation. In term fetuses, cord clamping is followed by regular lung ventilation and by the slow gradual increase of mean value in membrane potentials. The development of the mean membrane potential of cortical elements correlates well with the development of the cortical steady potential.     

Surface membrane antigen alteration on blood basophils in patients with Hymenoptera venom allergy under immunotherapy

BACKGROUND: Venom immunotherapy (VIT) provides widespread protection against systemic anaphylactic reactions after a sting of the respective insect. This effect is attributed to a shift from T(H)2 to T(H)1. However, because basophils also produce and release cytokines, such as IL-4 and IL-13, they may be part of the cytokine network. The cytokines may regulate basophilic granulocytes, as suggested by the presence of cytokine receptors IL-2Ralpha, GM-CSFRalpha, IL-1RII, IL-3R, IL-4R, IL-5R, and IL-6R on basophils from nonallergic donors. OBJECTIVE: The purpose of this study was to demonstrate that human basophils from subjects allergic to wasp venom undergoing VIT are regulated by cytokines, as shown by the alteration of the expression of cytokine receptors (and other markers). METHODS: The expression of the surface interleukin receptors and activation antigens on basophils from 19 nonallergic subjects and 48 patients with wasp venom allergy was investigated before, immediately after, and 1 week after VIT (20 patients only). RESULTS: Basophilic granulocytes in allergic subjects, compared with those in healthy persons, showed elevated expression of CD32 (FcgammaRII), CD122 (IL-2Rbeta), CD124 (IL-4Ralpha), CD130 (IL-6 and 11Rbeta), CD154 (CD40L), and HLA-DR. Activation of basophils clearly increased during VIT indicated by increased expression of CD32, CD33, CD35 (CR1), CD63, CD116 (GM-CSFRalpha), CD122, CD124, CD130, and CD154. HLA-DR expression also tended to increase. The expression of IL-5R (CD125) decreased. A significant decrease of the basophilic surface antigens CD11c, CD32, CD35, CD63, CD116, CD122, CD124, CD130, and CD132 (interleukin receptor gamma) was detected 1 week after the end of rush VIT. CONCLUSION: The rise in CD63 during VIT indicates a partial basophil degranulation with release of stored protein mediators, including IL-4. IL-4 may cause a transient upregulation of different surface antigens in an autocrine manner. Thereafter, cytokines released by T cells, which as a result of VIT have changed from a T(H)2 type to a more T(H)1 type, downregulate the activation of the basophilic granulocytes.     

Purification, primary structure, and biological activity of guinea pig neutrophil cationic peptides.

The guinea pig neutrophil cationic peptides GNCP-1 and GNCP-2 were purified from a granule-rich subcellular fraction of peritoneal exudate neutrophils by acid-gel electrophoresis and reversed-phase high-performance liquid chromatography. Both peptides not only released histamine from rat mast cells to the same extent but also were equally active against Staphylococcus aureus and Escherichia coli. The peptides were rich in arginine and cystine and lacked free sulfhydryl groups. Composition and sequence determinations revealed that GNCP-1 and GNCP-2 are each single polypeptides containing 31 amino acid residues and three intramolecular disulfide bonds. The complete amino acid sequence of GNCP-1 is Arg-Arg-Cys-Ile-Cys-Thr-Thr-Arg-Thr-Cys-Arg-Phe-Pro-Tyr-Arg-Arg-Leu-Gly- Thr-Cys - Ile-Phe-Gln-Asn-Arg-Val-Tyr-Thr-Phe-Cys-Cys. The sequence of GNCP-2 is identical except for the substitution of isoleucine for leucine at residue 21.     

Ultrastructural development of guinea pig cytomegalovirus in cultured guinea pig embryo cells.

The ultrastructural development of guinea pig cytomegalovirus (GPCMV) in guinea pig embryo cells was studied using electron microscopy. Tubular structures were found in nuclei of virus infected cells, followed by the appearance of intranuclear inclusions containing virus nucleocapsids. While some nucleocapsids were enveloped at the inner nuclear membrane, others were released into the cytoplasm where they were associated with, or within, dense matrix which was subsequently enveloped by cytoplasmic membranes to form enveloped dense virions. Dense bodies without virus capsids were formed in the cytoplasm and enveloped in a similar manner. An involvement of the nuclear pores in the release of unenveloped virus capsids from the nucleus to the cytoplasm was postulated. Evidence that the enveloped dense virions and dense bodies shared common envelope antigen(s) was obtained by immunoelectron microscopy. The similarities and differences in the ultrastructural development of GPCMV and other cytomegaloviruses are discussed.     

Contraction of guinea pig trachea with antibodies to guinea pig IgE. An in vitro model for asthma

Rabbit antiserum to guinea pig IgE was prepared. This antiserum absorbed IgE antibodies to dinitrophenyl determinants when examined by passive cutaneous anaphylaxis. This antiserum also provoked contraction of tracheal rings from normal guinea pigs in vitro. This system is a new model for asthma in which only IgE among immunoglobulins reacts.