Pulmonary function in workers exposed to low levels of fuel-oil ash

Previously, we reported significant lung function changes after exposure to fuel-oil ash during a boiler overhaul in which median PM10 and vanadium concentrations were 2.9 mg/m3 and 11.9 micrograms/m3, respectively. In this study, we examined prospectively 18 boilermakers involved in the short-term, partial overhaul of a large, oil-fired boiler where occupational exposures to PM10 and metals were relatively low. Vanadium and PM10 exposure levels were measured before and during boiler work. For PM10, median exposure before and during boiler work was 0.5 and 0.6 mg/m3, respectively. For vanadium, median exposure before and during boiler work was 1.0 and 12.7 micrograms/m3, respectively, comparable with the results of our previous study. Spirometric (PFT) testing was done three times: first day on the job (PFT1), end of overhaul (PFT2), and 2 weeks post-overhaul (PFT3). Spirometry results were analyzed using repeated measures analysis of variance. No significant differences were found. Boilermakers working on a short-term overhaul of an oil-fired boiler exhibited no significant change in any lung function parameter comparing pre-, during, and 2 weeks post-exposure. The comparatively low levels of exposure to PM10 and vanadium observed during boiler work, the short duration of the overhaul, and the healthy worker effect are possible explanations for these results.     

Hand-centred coding of target location in visuo-spatial working memory

The aim of the present experiment was to determine the frame of reference used to encode a visually specified target location, in a simple, visuo-spatial short-term-memory task, using delayed manual pointing. Subjects were required to remember the location of a single, visually presented stimulus, over delays of 3 and 30 s, and to recall its location by pointing to it with the tip of a stylus with eyes closed. There were two starting positions for the hand: one near the body, proximal to the target area, the other far from the body, i.e., beyond the target area. Two groups of twelve subjects participated in the experiment. One group observed the target locations in the light, the other group observed the target LEDs in the dark. The results showed a large (between 10-30%) and consistent undershoot of the remembered target location with respect to the hand's starting position, in the sagittal axis, both when the hand started from the near and from the far position. That is, from the far starting position. pointing errors lay consistently beyond the actual target location as seen from the subject's viewpoint. Further, this undershoot error in the remembered target location increased over time delay. These results are in favour of the hypothesis that the visual target locations were encoded in a hand-centred frame of reference in spatial short-term memory. They also implicate the use of motor- or action-related representations in visuo-spatial working memory.     

Primary infertility associated with schitosoma mansoni: a case report from the Jos plateau,north central Nigeria

Testicular schistosomiasis caused by Schistosoma mansoni is very rare and more so when associated with primary infertility. A 40 years old man from the Jos Plateau, North Central Nigeria presented with primary infertility after ten years of marriage. Sperm count revealed oligospermia and he also complained of inability to sustain erection. Testicular biopsy revealed several ova of Schistosoma mansoni in the connective tissue of the testes. Cases of infertility in endemic areas especially when there is no supply of potable water should raise suspicion of schistosomiasis among other pathologies and possible hormonal disturbances when the testes are involved.     

Intravenous gammaglobulin treatment of chronic idiopathic thrombocytopenic purpura

High-dose intravenous gammaglobulin (IVIgG) was given to 12 children and adults with chronic idiopathic thrombocytopenic purpura (ITP) to avoid splenectomy or because they either failed to respond to or required maintenance with high doses of steroids and/or immunosuppressives. The average platelet count increase to initial therapy was 239,500/microliters (range 23,000-790,000). A concomitant IgG Fc receptor blockade, measured by IgG-sensitized 51Cr-labeled autologous erythrocytes, was seen in 11 of 11 patients tested, both splenectomized and not splenectomized, lasting 3-4 wk. Six or more months after treatment, 2 children are in remission, 2 children and 2 adults are stable requiring no therapy with platelet counts of approximately 50,000 and 30,000, respectively, 3 children require maintenance IVIgG therapy at 2-10-wk intervals, and 1 child and 2 adults have become refractory to further IVIgG. Splenectomy was not performed in 4 children. Two adults were able to discontinue daily prednisone. The 3 patients who became unresponsive to Swiss Red Cross gamma-globulin (IgSRK) therapy did so in conjunction with a markedly elevated platelet-associated IgG and IgM. Serum IgM increased an average of 103 mg/dl after the IVIgG infusions. No significant side effects were seen.     

Carrier detection in hemophilia A: a cooperative international study. I. The carrier phenotype

Eight laboratories in six countries cooperated to clarify several issues concerning the phenotypes of heterozygous carriers of hemophilia "A." Plasma levels of factor VIII (F.VIII:C, formerly VIII:C) and von Willebrand factor (VWF:Ag, formerly VIIIR:Ag) of carriers and normal women were determined by various "in-house" methods; a single lyophilized plasma standard was used for all assays. Analysis of the collated data from 336 carriers (296 obligatory carriers and 40 sporadic carriers) and 137 normal women showed that there was no difference in the F.VIII:C levels of "paternal" carriers (women who had obtained the abnormal gene from their fathers) and "maternal" carriers. Neither was there a difference in the VWF:Ag levels of normal women and either type of carrier. Age was found to have a significant effect on both F.VIII:C and VWF:Ag, values being higher at very young and very old ages, the minima occurring in the 25- to 30-year range. ABO blood type had a striking effect. Women of types A, B, and AB (designated non- O in the study), both normals and carriers, had significantly higher levels of both factors than did women of type O. Analysis by laboratories showed that differences in mean levels of both factors between laboratories were highly significant. It was concluded that age, ABO blood type, and laboratory variation should be taken into account in carrier detection.     

Interrelationship between mitosis and endomitosis in cultures of human megakaryocyte progenitor cells [published erratum appears in Blood 1987 May;69(5):1547]

Sera from dogs rendered aplastic by total-body irradiation stimulate human bone marrow megakaryocyte progenitors to form megakaryocyte colonies in plasma clot cultures. In this investigation, we evaluated the effects of varying concentrations of such sera on both the mitotic and endomitotic phases of human megakaryocyte development in vitro. When low concentrations of aplastic canine sera (2.5% to 5.0% [vol/vol]) were added to cultures of human peripheral blood mononuclear cells in place of normal AB serum, megakaryocyte colony formation was augmented fivefold, cell numbers per colony increased approximately 2.5- fold, and the geometric mean megakaryocyte ploidy almost doubled. Further increasing the aplastic canine serum concentration from 10% to 30% (vol/vol) stimulated no additional colony formation. However, there was a further augmentation of cell numbers per colony associated with a progressive decrease in the mean megakaryocyte ploidy. Megakaryocyte cultures were harvested after 7, 12, 15, and 19 days of incubation, and these demonstrated that the lower mean ploidy values found at the higher concentrations of aplastic canine serum did not result from delayed endoreduplication. At all aplastic serum concentrations evaluated, there existed a strong correlation between nuclear ploidy and cell diameter. We conclude that both the mitotic and endomitotic events in human megakaryocytopoiesis may be influenced by a factor or factors present in aplastic canine serum. At lower in vitro concentrations, such sera stimulate both mitosis and endomitosis, which promotes the development of megakaryocyte colonies composed of larger cells with a higher mean ploidy. With increasing aplastic serum concentrations, colony formation plateaus and mitosis is favored over endomitosis. This results in colonies composed of more numerous but smaller megakaryocytes with a lower mean ploidy. Our data suggest that the size and extent of polyploidization that can be achieved by a developing megakaryocyte may be influenced by the mitotic prior history of its immediate precursor cell.     

Human interleukin-5 (IL-5) regulates the production of eosinophils in human bone marrow cultures: comparison and interaction with IL-1, IL-3, IL-6, and GMCSF

Recombinant human interleukin-5 (rhIL-5), in either liquid or semi- solid cultures, selectively induced eosinophil production from normal human bone marrow, with no activity on other cell lineages. The time course of eosinophil production induced by murine IL-5, rhIL-3, and rh granulocyte-macrophage colony stimulating factor (GMCSF) was similar to rhIL-5. The rate of eosinophil maturation in vitro was independent of the stimulating cytokine, mature eosinophils being produced after 4 to 5 weeks in liquid culture with each of these cytokines. The eosinophils produced in response to each cytokine were morphologically indistinguishable, and had the ultrastructural features of maturity except that the electron-dense material in the granules had not formed into crystalline cores. Neither rhIL-1 nor rhIL-6 alone, or in combination with rhIL-5 or rhIL-3, induced eosinophil differentiation or proliferation under the conditions used. rhIL-3 and rhGMCSF induced more eosinophil colonies than rhIL-5, rhIL-5 had an additive, not synergistic, effect on eosinophil colony production when combined with either rhIL-3 or rhGMCSF, suggesting that rhIL-5 stimulates a smaller and possibly different population of eosinophil progenitors. However, rhIL-5 induced the greatest eosinophil production in liquid cultures, suggesting that although it may act on a smaller population of precursors, it is able to stimulate more proliferative steps than either rhIL-3 or rhGMCSF.     

Restriction of cell lysis by homologous complement: II. Protection of erythrocytes against lysis by newly activated complement

Our previous work revealed that homologous complement (C) was ineffective in lysing antibody-sensitized erythrocytes (EA) even at high concentrations. It was also shown that activation of complement on homologous EA resulted in the binding of C9 and the formation of EA bearing complement proteins C1 through C9 (EAC1-9), yet few hemolytic sites were formed. Instead, as shown here, the formation of homologous EAC1-9 caused the cells to become resistant to lysis even by heterologous complement during a second incubation. In contrast, when homologous EAC1-8 were produced by incubating EA with C9-depleted serum, such intermediates were not protected against lysis by heterologous complement during a second incubation. Furthermore, homologous C9 on EAC1-9 was able to reduce the hemolytic efficiency of heterologous complement without blocking C activation and the formation of new C5b-9 complexes. Protection was not modified when homologous EAC1-9 were produced in one step, by incubation of EA with serum, or sequentially by adding C9 to EAC1-8. The minimum number of 9-sites required to confer a protective effect on EAC1-9 was less than 200 per cell. Thus, in addition to its known effect in heterologous cell killing, homologous C9 is capable of protecting homologous cells against inadvertent complement lysis.