Monoclonal antibodies specific to a Ca2(+)-bound form of lipocortin I distinguish its Ca2(+)-dependent phospholipid-binding ability from its ability to inhibit phospholipase A2.

Lipocortin I, a Ca2(+)-and phospholipid-binding protein without EF-hand structures, has many biological effects in vitro. Its actual role in vivo, however is unknown. We obtained and characterized five monoclonal antibodies to lipocortin I. Two of these monoclonal antibodies (L2 and L4-MAbs) reacted with the Ca(+)-bound form of lipocortin I, but not with the Ca2(+)-free form, both in vivo and in vitro. Lipocortin I required greater than or equal to 10 microM-Ca2+ to bind the two antibodies, and this Ca2+ requirement was not affected by phosphatidylserine. L2-MAb abolished the phospholipase A2 inhibitory activity of lipocortin I and inhibited its binding to Escherichia coli membranes and to phosphatidylserine in vitro. L4-MAb abolished the phospholipase A2 inhibitory activity of lipocortin I, but did not affect its binding to E. coli membranes or to phosphatidylserine. These findings indicated that the inhibition of phospholipase A2 by lipocortin I was not simply due to removal or capping of the substrates in E. coli membranes. Furthermore, an immunofluorescence study using L2-MAb showed the actual existence of Ca2(+)-bound form of lipocortin I in vivo.     

A toxic substance produced by Nocardia otitidiscaviarum isolated from cutaneous nocardiosis

During our studies on toxic substances from clinically isolated Nocarida, a new isolate identified as Nocardia otitidiscaviarum from cutaneous nocardiosis was found to produce a toxic substance called HS-6 that had strong in vitro as well as in vivo toxicity. The mouse intraperitoneal LD₅₀ value was 1.25 mg/kg and the ED₅₀ value for L1210 cultured cells was 0.3 ng/ml. The structure of HS-6 was determined and found to belong to the 16-membered macrocyclic group with a molecular formula of C₄₃H₆₈O₁₂. HS-6 also showed activity against pathogenic fungi such as Cryptococcus neoformans.     

Appearance of retrogradely labeled neurons in the rat superior cervical ganglion after injection of wheat-germ agglutinin-horseradish peroxidase conjugate into the contralateral ganglion

Summary Injection of wheat-germ agglutinin-horseradish peroxidase conjugate (WGA-HRP) into the superior cervical ganglion (SCG) of the rat results in accumulation of WGA-HRP in sympathetic postganglionic neurons in the contralateral SCG. The sympathetic pathways involved and the mechanism underlying the labeling were investigated. The labeling in neurons in the contralateral SCG was apparent 6 h after injection and increased in intensity with longer survival times. The number of labeled neurons reached 1300 at 72 h after the injection. Transection of the external (ECN) or internal carotid nerves (ICN) resulted in considerable reduction in the number of labeled neurons. Combined transection of both ECN and ICN virtually eliminated labeling in the contralateral SCG. This provides strong evidence that these two nerves are the major pathways for WGA-HRP transport out of the SCG. No labeling was observed in the contralateral SCG following injection of horseradish peroxidase (HRP). Therefore, it seems unlikely that a direct nerve connection exists between the bilateral ganglia. Instead, the labeling of contralateral SCG neurons appears to depend on the transneuronal transport capacity of WGA-HRP, which conveys the marker in an anterograde direction along the postganglionic fibers to terminals in sympathetic target organs, and then delivers it transneuronally to contralateral SCG neurons. We suggest that the sympathetic nerve fibers originating in the bilateral SCGs run intermingled and are in close contact in their peripheral target organs.     

A newly established human acute lymphoblastic leukemia cell line with characteristics of the earliest B-cell maturation

A new human acute lymphoblastic leukemia (ALL) cell line, designated HBL-3, was established from the bone marrow of a patient with non-T-ALL. The HBL-3 cell line expressed B4 (CD 19), BA-1 (CD 24) and HLA-DR antigens, but not surface immunoglobulin (SIg) or cytoplasmic immunoglobulin (CIg). The cell line lacked the common acute lymphoblastic leukemia antigen (CALLA) and antigenic markers characteristic of T-cell and myeloid cell lineages. The HBL-3 cells had structural rearrangements of both the homologous chromosome 9s, including a translocation with chromosome 1 which has been reported in a patient with common ALL. The cell line had rearranged immunoglobulin heavy chain genes but retained germ-line κ light chain genes and germ-line T-cell receptorβ- and γ-chain genes. The HBL-3 cell line was strongly positive for terminal deoxynucleotidyl transferase (TdT). These findings indicate that the HBL-3 cell line is derived from the earliest B-cell committed to B-cell lineage.     

Protection of mice against Sendai virus pneumonia by non-neutralizing anti-F monoclonal antibodies

Nine monoclonal antibodies (MAbs) directed to F protein of Sendai virus were obtained and characterized for their protective ability against Sendai virus infection in mice. None of the MAbs showed hemagglutination-inhibition (HI), hemolysis-inhibition (HLI), or neutralization (NT) activities in vitro when assayed by standard methods. Some of the MAbs, however, showed complement-requiring NT (C-NT) and complement-requiring hemolysis (C-HL) activities when assayed in the presence of complement. Passive immunization experiments revealed that the MAbs with higher C-NT and C-HL activities showed protective activity against Sendai virus pneumonia in mice, and that some MAbs with IgG1 isotype having neither C-NT nor C-HL activity also showed the protective activity. Digestion of the MAbs with pepsin which split immunoglobulin molecules into F(ab')2 and Fc fragments greatly suppressed the protective activity. These results suggest that not only complement-mediated immunological responses such as immune virolysis but also antibody-dependent cellular cytotoxicity (ADCC) and/or immune phagocytosis, in which complement system is not necessarily involved, play an important role in the protection of mice from Sendai virus infection.     

Dichogamy, Sex Allocation, and Mating System of Campanula microdonta and C. punctata

Dichogamy and sex allocation in several populations of Campanula microdonta and C. punctata were investigated with regard to their mating systems. Duration of the staminate phase differed among the populations: staminate phase was longer in self-compatible (SC) and largely outcrossing populations than in self-incompatible (SI) and outcrossing populations or in SC and largely inbreeding populations. Duration of the pistillate phase among the populations was less variable than duration of the staminate phase. Male reproductive effort decreased with increase of the estimated selfing rates. Male allocation (weight ratio of androecium to gynoecium or to total flower) may be used as an indicator of the breeding system. Within each population, small flowers allocate proportionately more resources to the androecium than to the gynoecium. Among populations, SC outcrossing populations tend to produce large ovaries, and SC inbreeding populations tend to produce small ovaries.     

Effects of hydrocortisone and aminophylline on plasma leukotriene C4 levels in patients during an asthmatic attack

To study the role of leukotriene C4(LTC4) and the effect of hydrocortisone and aminophylline on plasma LTC4 levels in patients with asthmatic attacks, we measured LTC4 in plasma of 18 asthmatics during a wheezing attack and of 7 normal subjects. Blood samples were obtained before and after treatment with aminophylline and/or hydrocortisone injections. We extracted LTC4 using a Sep-Pak C18 cartridge for the measurement of LTC4 by radioimmunoassay. The plasma levels of immunoreactive LTC4 (i-LTC4) of the normal subjects were 142 +/- 25 pg/ml (n = 7), while those of nonatopic type asthmatic patients with wheezing attacks were 208 +/- 68 pg/ml (n = 15) (p less than 0.01). Before and after treatment with both hydrocortisone succinate (100 mg) and aminophylline (250 mg), 6 asthmatic patients with wheezing attacks had a mean plasma level of i-LTC4 181 +/- 24 and 132 +/- 18 pg/ml (p less than 0.01), respectively. On the other hand, the treatment with aminophylline 250 mg alone increased the i-LTC4 levels from 178 +/- 19 pg/mg to 213 +/- 16 pg/mg (n = 6)(p less than 0.05), while treatment with hydrocortisone succinate 100 mg decreased the i-LTC4 level 0.05 from 284 +/- 99 pg/ml to 249 +/- 85 pg/ml (n = 4)(p less than 0.05). In conclusion, the present study shows that the i-LTC4 level in venous blood of patients with asthmatic attacks is decreased significantly by treatment with hydrocortisone succinate.     

Ornithine decarboxylase antizyme in kidneys of male and female mice.

Antizyme, a protein inhibitor of ornithine decarboxylase (ODC), was shown to be induced in mouse kidney by repeated injection of putrescine. Antizyme was also present as a complex with ODC in the kidney of untreated mouse. The amount of the renal ODC-antizyme complex was 3-fold higher in male mice than in female mice. On the contrary, the proportion of ODC present as a complex with antizyme was 24-fold higher in females than in males, and the decay of renal ODC activity after cycloheximide treatment was about 5-fold more rapid in females than in males. Administration of testosterone to female mice, a procedure known to prolong the half-life of renal ODC, increased both ODC activity and the content of ODC-antizyme complex, but decreased the antizyme/ODC ratio in the kidney. These results are consistent with the previous observation in HTC cells that the decay rate of ODC activity in the presence of cycloheximide correlated well with the proportion of ODC present as a complex with antizyme, suggesting the ubiquitous role of antizyme in ODC degradation.     

A re-evaluation of the cytology of cat Pacinian corpuscles

Summary The ultrastructure of cat mesenteric Pacinian corpuscles in cross and longitudinal sections has been examined. The terminal ends of lamellar cells of the inner core have been identified in longitudinal sections through the proximal portion of the inner core. These terminal bulbous expansions contain characteristic concentric membranes of rough endoplasmic reticulum and in some cases masses of oval membranous inclusions. The central axon as seen in cross section is oval in profile, having X-(short) and Y-(long) axes, and each axonal face is characterized by specializations of the axolemma. At the X-axis, the inner lamellae of the inner core tightly abut a smooth axolemma, with no intervening connective tissue matrix, in a manner reminiscent of a neuroepithelium. The axolemma of the Y-axis has numerous axonal spines (microspikes) that project into the cleft in the inner core. The extent of the axolemma having axonal spines can only be appreciated in longitudinal sections. The clefts contain a specialized connective tissue with elastic and collagen fibrils. The connective tissue compartment of fibers and matrix separating individual inner core lamellae is unique, in that it contains extremely thin collagen fibrils measuring approximately 15 nm in diameter. The diameter of collagen fibrils increases as the cleft is approached. Here the fibrils resemble typical endoneural collagen.