Identification of receptors for platelet-activating factor in rat Kupffer cells

Ligand binding studies demonstrated that isolated rat Kupffer cells possess high affinity binding sites for platelet-activating factor (1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine, AGEPC). AGEPC binding reached saturation within 10 min at 25 degrees C and was reversible. A Scatchard analysis revealed a single class of AGEPC receptors numbering about 10,600 sites/cell and possessing a dissociation constant of 0.45 nM. Similar values for the dissociation constant for AGEPC (0.12 and 0.34 nM) were obtained independently by kinetic analysis of specific AGEPC binding. AGEPC binding was stereospecific and was inhibited by Zn2+ and AGEPC receptor antagonists including BN52021 and U66985. The AGEPC receptor was functionally active since it was shown to mediate arachidonic acid release and eicosanoid production in Kupffer cells, and these events were inhibited by AGEPC receptor antagonist BN52021. The receptor-mediated arachidonic acid release was extracellular calcium-dependent and was abolished by calcium channel blocker prenylamine and by [ethylenebis(oxyethylenenitrilo)]tetraacetic acid, indicating that calcium influx through a receptor-regulated calcium channel in the plasma membrane is involved in the AGEPC-induced arachidonic acid release. It is suggested that rat Kupffer cells have specific and functionally active AGEPC receptors which are involved in signaling mechanisms which govern the production of several other autacoid-type mediators in the liver.

Phagocytosis of Treponema pallidum pertenue by hamster macrophages on membrane filters

The role of the macrophage in destruction of virulent treponemes is disputed. A major obstacle has been the inability to demonstrate quantitative phagocytosis of treponemes by macrophages. Treponema pallidum pertenue was attached to polycarbonate filters for assessment of treponemal phagocytosis by macrophages. The disappearance of treponemes due to phagocytosis was measured by enumeration with immunofluorescence. Resident and lipopolysaccharide-activated macrophages were found to phagocytize treponemes equally well. The phagocytosis of killed treponemes by macrophages was enhanced by opsonization with immune serum. Macrophages successfully phagocytized Staphylococcus aureus organisms when they were incubated on filters under identical conditions. Treatment of macrophages with cytochalasin B, a known inhibitor of phagocytosis, prevented the disappearance of treponemes and phagocytosis of S. aureus. In addition, fluorescent treponemal debris was observed only inside macrophages cultured with treponemes. These results demonstrate that macrophages can phagocytize pathogenic treponemes on polycarbonate filters.

[Clonal propagation of Gynostemma pentaphyllum (Thumb.) Makino in test tubes]

The explants taken from adventitious shoots or nodes of adventitious bud of Gynostemma pentaphyllum produced numerous shoots on MS medium supplemented with BA 1mg/L and IAA 0.05 mg/L. When the segments of shoots were grown on the 1/2MS medium supplemented with IBA 1 mg/L, roots were initiated differentiating to plantlets. Substitution of polyurethane sponge for agar can accelerate the growth of platlets.

Potentially lethal ventricular arrhythmias: from mundane to esoteric

Patients with potentially lethal ventricular arrhythmias (VAs) represent a heterogenous group with frequent and high grade ventricular arrhythmias (including couplets and runs of nonsustained ventricular tachycardia), structural heart disease and decreased left ventricular function. This is a group at intermediate risk of sudden death, with risks varying from 10% to 38%. The electrical and mechanical risks of patients with potentially lethal VA is discussed in relation to their ability of promoting sudden death. The studies reviewing the impact of antiarrhythmic treatment on survival of patients with potentially lethal VA is discussed.

[Fiberscopic study of velopharyngeal function in 170 normal subjects]

This paper established a quantitative methodology for evaluating the velopharyngeal function (VPF) using NPF. The reliability of this method was testified. On the basis of this result, the observation of normal velopharyngeal function was carried out in 170 normal individuals. The authors presented the percentage of VPI during phonating five Chinese vowels, the highest one was "a" (52.3%), the lowest ones were "i" and "u" (7.1% and 5.3%). The extent of VPI was measured, the mean of "a"'s RVPI was 13.9%, and the means of "i"'s and "u"'s RVPI were 9.3% and 9.7% respectively. The authors suggested the RVPI "i" and RVPI "u" as two parameters for assessing VPF.

Effects of tensile stress on the R lines of Cr(3+) in a sapphire fiber

We have investigated the spectroscopic properties of a crystalline sapphire fiber unintentionally doped with Cr(3+). We find that tensile stress produces blue shifts of the R lines and changes in their radiative lifetimes and integrated intensities that can be correlated to stress-induced changes of the crystal-field parameters.

Synergistic effect of macrophage activation and immune serum, especially IgG2, on resistance to infection with Treponema pallidum ssp. endemicum in hamsters

Experimental studies have indicated that macrophages are involved in the pathogenesis of syphilis. Whether macrophages alone or with immune serum are ultimately responsible for killing of treponemes is disputed. We have demonstrated that BCG-vaccinated hamsters administered normal serum contained fewer treponemes in the inguinal and popliteal lymph nodes than did the nonvaccinated controls. When BCG-vaccinated hamsters were injected with syphilitic immune serum and challenged with Treponema pallidum ssp. endemicum, treponemicidal activity was enhanced. Treponemicidal activity was also detected in BCG-vaccinated hamsters challenged with treponemes treated in vitro with immune serum and its immunoglobulin fractions, especially IgG2. The immune IgG2 fraction had more treponemicidal activity than did the immune IgG1 fraction and the unfractionated immune serum. Our observations indicate an important synergistic role for macrophages and immune serum, especially IgG2, for elimination of T. pallidum ssp. endemicum from the host.

[Study of anticancer human monoclonal antibody--establishment of human monoclonal antibody to gastric cancer by human-mouse hybridoma]

A human immunoglobulin M (IgM) antibody secreting hybridoma, HMG1, has been established and studied for its reactivity against human gastric cancer cells. Lymphocytes isolated from a regional lymph node of patient with gastric adenocarcinoma were fused with mouse myeloma cells NS-1. Supernatants from the generated human-mouse hybrids were first screened for immunoglobulin production by ELISA. The identified human IgM-secreting hybridomas were expanded and subcloned for further analysis or cryopreservation. The screening for binding of antibodies to a panel of human cancer cell lines and normal fibroblast was carried out with PAP or indirect immunofluorescence stain. The selected hybridoma, HMG1 after being cloned three times, was stable in secreting IgM (about 4 micrograms/1 x 10(6) cells) for more than 9 months. Large amount of ascites was obtained by injecting this hybrid to BALB/C nude mice pretreated with anti-lymphocyte serum and pristane. The ascitic fluid contained 5-19 mg human Ig/ml. Subsequently this IgM was extracted from ascitic fluid by saturated ammonium sulphate solution. This crude extract was further purified with immuno-affinity chromatography. Both this purified ascite-IgM as well as IgM from HMG1 supernatant would react with gastric cancer cell line BGC-823 but not with human normal fibroblasts 350Q by PAP or immunofluorescence analysis. The human HMG1-IgM reacted with gastric cancer cells on paraffin embedded tissue section but did not react with normal gastric mucosa cells. HMG1-IgM had some complement dependent cytotoxicity against BGC-823. These results suggest that the establishment of anticancer human monoclonal antibodies with human-mouse hybridoma technique be feasible. There is a possibility for clinical applications of this human monoclonal antibody in the future.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of Carbon Black on the J-Integral and Strain Energy in the Crack Tip Region in a Vulcanized Natural Rubber

1) The J-integral is path independent in both PS and SEN specimens and equals the tearing energy. 2) The critical J-integral at initiation is less in PS specimens than in SEN specimens, because the greater biaxial stress in PS restricts the process zone. 3) At initiation, the crack-tip radius, proportional to the local strain, is independent of CB. 4) The energy density within and the size of the process zone near the crack tip increase with CB; these are major contributions to CB reinforcement.

[Alteration of plasma amino acid content in primary liver cancer patients]

Twenty-two plasma free amino acid contents from 22 primary liver cancer (PLC) patients were assayed by means of HPLC and compared with those from 16 normal subjects. The results showed that in PLC patients, plasma total amino acid (TAA), branched chain amino acid (BCAA), glycogenic amino acid, glutamine, histidine and arginine were lowered, while plasma aromatic amino acid (AAA) and methionine did not decrease significantly resulting in the BCAA/AAA ratio decline. Comparing 8/22 subclinical and 14/22 clinical liver cancers with healthy controls respectively, it was found that there was a decrease of plasma TAA, glutamine, arginine, histidine, BCAA and BCAA/AAA ratio, and an increase of tyrosine, in subclinical stage of PLC. It suggests that alteration of most amino acids occur in the early stage of PLC and become more obvious in the moderate and late stages. The changes of plasma amino acid contents in PLC were different from those in chronic liver diseases. The alteration of plasma amino acid contents in subclinical stage of PLC suggests that the disturbance of amino acid metabolism be resulted from malignancy. Correction of the amino acid metabolic disturbance in PLC patients may enhance the inhibition of tumor growth and improve the host metabolism and anti-cancer effect.

Localization of antigen-specific lymphocytes following lymph node challenge

The effect of subcutaneous injections of Brucella abortus strain 19 antigen on the specific localization of autologous lymphocytes in the regional nodes of calves was analysed by fluorescent labelling and flow cytometry. Both in vitro and in vivo FITC labelling of lymphocytes indicated the preferential migration of lymphocytes from a previously challenged lymph node to a recently challenged lymph node. However, lymphocytes from a lymph node challenged with B. abortus failed to localize preferentially in a lymph node challenged with a control antigen, Listeria monocytogenes. Lymph node cells, enriched for T lymphocytes and isolated from primary stimulated or secondary challenged B. abortus lymph nodes, could proliferate when cultured with autologous antigen-pulsed macrophages. The kinetics of [3H]thymidine incorporation in lymphocytes from secondarily challenged lymph nodes occurred earlier and to a greater extent when compared with lymphocytes from primary challenged lymph nodes. Our data show that the accumulation of B. abortus-specific lymphocytes in secondarily challenged lymph nodes is increased by the presence of the specific antigen.

The induction of meningeal inflammation by components of the pneumococcal cell wall

Pneumococcal cell wall induces meningeal inflammation in rabbits injected intracisternally with greater than 10(5) cell equivalents. Both of the major cell wall components, teichoic acid and peptidoglycan, contribute to this inflammatory activity although responses differ depending on the chemical nature, size, and complexity of these fractions. Challenge with teichoic acid (membrane or wall associated) results in greater inflammation at 5 hr than at 24 hr. Degraded teichoic acid is inactive. In contrast, the inflammation caused by whole cell wall or high-molecular-weight peptidoglycan-containing fractions increases in intensity from 5 to 24 hr. Peptidoglycan fractions lose activity at 24 hr when hydrolyzed to disaccharide-stem peptide moieties. Generation of free cell wall components in cerebrospinal fluid as, for example, during treatment with antibiotics that are bacteriolytic as well as bactericidal, could contribute to increased inflammation in the subarachnoid space.

Retinal changes in myotonic dystrophy: a clinicomorphological study

This report appears to be the first ultrastructural study of the maculopathy and peripheral pigmentary retinopathy in myotonic dystrophy. Nine eyes from five patients observed during life are described. The findings were similar in all eyes, the retinal pigment epithelium in the macular region containing an accumulation of lipofuscin in large hyperpigmented cells. Pigment-laden profiles found in the subpigment epithelial space or subretinal space were interpreted as an attempt to discharge the pigment. Stress fibres of actin microfilaments were thrown into prominence by the irregularity of the pigment epithelium. In the periphery migration of retinal pigment cells into the retina occasionally resulted in the formation of bone corpuscles around occluded vessels, as occurs in retinitis pigmentosa; but more often the clumps were coarser and surrounded basement membrane material. Central and peripheral epiretinal membranes were also observed.

Repositioning of Descemet's membrane: a case report

An 80-year-old Australian was admitted to Concord Hospital for right cataract extraction and intraocular implant. During the procedure under local anaesthesia, two-thirds of Descemet's membrane was stripped down into the anterior chamber. The membrane was later repositioned by air injection into the anterior chamber. Sixteen months later, her right visual acuity is 6/9 and she reads the newspapers.

Objective pathological diagnosis of coal worker's pneumoconiosis

Pertinent pathological features of lungs obtained at autopsies from 99 coal miners were compared with those observed in the lungs of 268 male town dwellers of comparable age who were not occupationally related to the coal mining or other industries at risk for development of pneumoconiosis. The degree of anthracotic pigment deposition and severity of type of pigmented lesion with its accompanying reticulum fiber formation and fibrosis were significantly greater in lungs of miners. There was a high degree of overlap in degree of pigment deposition, particularly those quantitated as grades 1 and 2 and in lesions regarded as types 1 and 2. The greatest divergence was observed for prevalence of nodular pulmonary lesions (type 4). There was also a considerable divergence in the type 3 alteration characterized by nonnodular aggregates of carbon-laden macrophages accompanied by minimal reactive fibrosis. It appears that an objective pathological diagnosis of coal workers' pneumoconiosis (CWP) can be rendered only by the demonstration of type 4 lesions. Approximately 25% of coal miners exhibited unequivocal features of CWP. No significant differences concerning incidence or types of emphysema or frequency of chronic cor pulmonale were encountered between the two populations.

Correlation of estrogen receptor and pathologic characteristics of invasive breast cancer

Estrogen receptor (ER) status was correlated with a large number of pathological and clinical characteristics of 178 invasive breast cancers. Positive ER was found to be significantly associated with high nuclear and low histologic grades, absence of tumor necrosis, presence of marked tumor elastosis, and older patients. These pathologic parameters enumerated are either directly or indirectly related to tumor differentiation suggesting that ER represents another index of this latter. Multivariate analyses disclosed that both age and tumor differentiation are associated with the ER status. Well-differentiated tumors were more frequently ER+ in older women. Inclusion of an estimate of tumor necrosis as well as patient age appears to allow for further discrimination of ER status in poorly differentiated lesions. Considerations relative to ER and tumor differentiation provide a possible explanation for the dichotomy of response to adjuvant chemotherapy observed in pre and postmenopausal women.