Activation of superoxide production and differential exocytosis in polymorphonuclear leukocytes by cytochalasins A,B, C,D and E: Effects of various ions

All of the common cytochalasins activate superoxide anion release and exocytosis of β-N-acetylglucosaminidase and lysozyme from guinea-pig polymorphonuclear leukocytes (neutrophils) incubated in a buffered sucrose medium. Half-maximal activation of both processes is produced by approx. 2 μM cytochalasin A, C >μM cytochalasin B ? 4–5 μM cytochalasin D, E. While maximal rates of O₂^? release and extents of exocytosis require extracellular calcium (1–2 mM), replacing sucrose with monovalent cation chlorides is inhibitory to neutrophil activation by cytochalasins. Na⁺, K⁺ or choline inhibited either cytochalasin B- or E-stimulated O₂^? production with IC₅₀ values of 5–10 mM and inhibition occurs whether Cl^?, NO₃^? or SCN^? is the anion added with Na⁺ or K⁺. Release of β-N-acetylglucosaminidase in control or cytochalasin B-stimulated cells is inhibited by NaCl (IC₅₀ ≈ 10 mM), while cytochalasin E-stimulated exocytosis is reduced less and K⁺ or choline chloride are ineffective in inhibiting either cytochalasin B- or E-stimulated exocytosis. Release of β-glucuronidase, myeloperoxidase or acid phosphatase from neutrophils incubated in buffered sucrose is not stimulated by cytochalasin B. Stimulation of either O₂^? or β-N-acetylglucosaminidase release by low concentrations of cytochalasin A is followed by inhibition of each at higher concentrations. It appears that all cytochalasins can activate both NAD(P)H oxidase and selective degranulation of neutrophils incubated in salt-restricted media and that differential inhibition of these two processes by monovalent cations and/or anions is produced at some step(s) subsequent to cytochalasin interaction with the cell.     

Hyperthermic treatment of chromomycosis with disposable chemical pocket warmers

A case of chromomycosis in which hyperthermia proved effective is reported. The patient was a 56-year-old male bean curd maker who, without any previous history of minor trauma, developed on the extensor side of the left upper arm an eczematous lesion that underwent gradual radial expansion. The lesion showed a well-defined, 7×10 cm infiltrated erythematous plaque with the central area healed and, at the upper and lower borders, adherent scales and crusts on the surface. Histological examination revealed granulomatous changes in the dermis, as well as sclerotic cells within giant cells and microabscesses. On culturing,Fonsecaea pedrosoi was isolated. The patient was treated with disposable chemical pocket warmers, which were secured over the lesion with a rather tight elastic bandage, so that they kept the affected area warm for 24 hours a day. After a month of such hyperthermic treatment, the erythema and infiltration had decreased considerably, and microscopic examination and culture of the crusts both yielded negative results. Examination of biopsy specimens of the lesion after the third month showed that it had cicatrized. The treatment was stopped after 4 months, and no relapse occurred. We also summarize the published results of local hyperthermic treatment of chromomycosis in Japan.     

Identification of HLA-B44 subtypes associated with extended MHC haplotypes

The HLA class I antigen B44 is found in each of two different extended major histocompatibility haplotypes (allele combinations of HLA-B, HLA-DR, and complement genes BF, C2, C4A, and C4B in linkage disequilibrium). Using isoelectric focusing, two variants of HLA-B44 were identified. The basic variant was found in all cell lines with the extended haplotype HLA-B44, DR7, FC31, and the acidic variant in all cell lines with the extended haplotype HLA-B44, DR4, SC30. The occurrence of each antigen variant with a unique extended haplotype explains previous observations concerning the nonrandom association of B44 variants with DR antigens.     

Electrical PD,short-circuit current and fluxes of Na and Cl across avian intestine

In vitro measurements were made of transmural potential difference (PD), short-circuit current (Isc), resistance and unidirectional fluxes of 22Na and 36Cl across the duodenum, jejunum, ileum and colon of normal sodium-replete domestic fowl (Gallus domesticus). The PD ranged from about 1 mV across the duodenum to 8 mV across the colon while the Isc was, respectively, 2.8 and 64 microA X cm-2. The jejunum and ileum exhibited values between these extremes. Unidirectional fluxes (under short-circuit conditions) of Na and Cl were lowest across the duodenum where there was no evidence of active transport of these ions. Unidirectional fluxes of Na and Cl were less across the jejunum than across the ileum or colon. A net active transport of Na (but not Cl) was observed in the ileum (= 106% of the Isc) and colon (= 50% of Isc). The possible physiological significance of these observations in the domestic fowl are discussed and are compared to that of a mammal, the rabbit.     

Bone marrow stromal proteoglycan heterogeneity: phenotypic variability between cell lines and the effects of glucocorticoid

Hematopoiesis in vivo is dependent upon the interaction of hematopoietic stem cells with a complex microenvironment, of which stromal proteoglycans are an important functional component. Certain bone marrow stromal cell lines provide a microenvironment that supports hematopoiesis in vitro, a function that is dependent upon glucocorticoid supplementation. Proteoglycan synthesis in the hematopoietic-supportive D2XRII, Bl6 and 14F1 bone marrow stromal cell lines was studied by 35S-sulfate precursor labelling and ion-exchange separation, followed by isopyknic CsCl density centrifugation and gel filtration HPLC. The effects of glucocorticoid were also investigated. A similar pattern of proteoglycan heterogeneity was observed in all three cell lines, although there was considerable quantitative variation. All cultures synthesized three species of chondroitin/dermatan sulfate (CS/DS) proteoglycans: DS1, excluded from a Bio-Sil TSK-400 HPLC column, and DS2, eluting at Kd = 0.31, were present mainly in the culture media. The smallest (DS3) eluted at Kd = 0.63 and was present mainly in the cell layers. CS/DS species were the major proteoglycans in all cultures. Hydrocortisone-free cultures also synthesized heparan sulfate (HS) proteoglycans, including a cell-associated form (HS1), partially excluded from the TSK-400 column, and a secretory form (HS2), eluting at Kd = 0.15. D2XRII cells also secreted an apparently-unique, high-density proteoglycan, Kd = 0.65, into the culture medium. Hydrocortisone at 10(-6) M virtually abolished HS proteoglycan synthesis in all three cell lines, and altered the pattern of CS/DS proteoglycans in the culture media, increasing the quantity of DS1 and DS3, and reducing the quantity of DS2.     

Pulmonary paracoccidioidomycosis in immunized mice

Paracoccidioidomycosis was induced in immunized (IM) and non-immunized (NI) mice. The histopathology, the number of fungi in the lungs, the cellular (footpad test — FPT and macrophage inhibition factor assay — MIF) and humoral (immunodiffusion test) immune response were investigated serially postinfection. In the IM mice, at days 1 and 3, there was intense and predominant macrophagic-lymphocytic alveolitis with loose granulomatous reaction; at day 30, inflammation was mild. In the NI group, up to day 3, the lesions were focal; later there was formation of extensive epithelioid granuloma. The number of fungi in IM mice were always smaller than those of NI group. Immunization alone induced positive FPT and MIF indices with low titer of antibody. After infection, there was a significant decrease of the FPT indices in the IM group, which we interpreted as desensitization due to trapping of sensitized lymphocytes in the lungs. In conclusion, (1) The lesional pattern of pulmonary paracoccidioidomycosis in IM mice was similar to that of a hypersensitivity pneumonitis. This reaction was probably effective in reducing the extension of the infection and decrease the number of fungi. (2) In this model, pulmonary resistance against P. brasiliensis seems to be related to local and systemic delayed-type hypersensitivity reaction.