Reconsideration of discrepancies between clinical and histopathological features in acute eosinophilic pneumonia.

BACKGROUND AND OBJECTIVES: Acute eosinophilic pneumonia (AEP) is a very rare condition, with only one paper published so far discussing histopathological findings at surgical biopsy. In that paper, AEP is considered to be an acute and proliferative stage of DAD accompanied by eosinophilia. However, acute respiratory distress syndrome, acute interstitial pneumonia, and acute exacerbation of idiopathic pulmonary fibrosis, which, unlike AEP are mostly life-threatening diseases, also exhibit DAD. AEP also presents with severe hypoxia but rapidly improves on treatment with corticosteroids alone, without subsequent fibrosis. In contrast, the other above-mentioned diseases with the same histopathology show greatly different clinical courses. The reasons for these differences remain unclear. METHODS: Here we investigated the histopathology of AEP in 2 surgical lung biopsy and 14 transbronchial lung biopsy cases. Additionally, we determined the presence or absence of different phases of DAD by histopathology in these AEP cases. RESULTS AND CONCLUSION: Characteristic histopathological findings of AEP consist of alveolar edema with infiltration of eosinophils and lymphocytes and edema of perivascular area and interlobular septa. The alveolar spaces showed fibrinous exudates. There were no hyaline membranes or massive intraluminal fibrosis. These histopathological findings of interstitial edema and fluid exudates are consistent with radiological findings of lung edema and can explain the rapid and complete improvement.Because AEP does not exhibit lung fibrosis histopathologically, it should not to be included in DAD which is associated with lung fibrosis.

Effects of hypoxia on alveolar fluid transport capacity in rat lungs.

There is little information regarding the effect of hypoxia on alveolar fluid clearance capacity. We measured alveolar fluid clearance, lung water volume, plasma catecholamine concentrations, and serum osmolality in rats exposed to 10% oxygen for up to 120 h and explored the mechanisms responsible for the increase in alveolar fluid clearance. The principal results were 1) alveolar fluid clearance did not change for 48 h and then increased between 72 and 120 h of exposure to hypoxia; 2) although nutritional impairment during hypoxia decreased basal alveolar fluid clearance, endogenous norepinephrine increased net alveolar fluid clearance; 3) the changes of lung water volume and serum osmolality were not associated with those of alveolar fluid clearance; 4) an administration of beta-adrenergic agonists further increased alveolar fluid clearance; and 5) alveolar fluid clearance returned to normal within 24 h of reoxygenation after hypoxia. In conclusion, alveolar epithelial fluid transport capacity increases in rats exposed to hypoxia. It is likely that a combination of endogenous norepinephrine and nutritional impairment regulates alveolar fluid clearance under hypoxic conditions.

Synthesis of diaminobutane derivatives as potent Ca(2+)-permeable AMPA receptor antagonists.

We synthesized diaminobutane derivatives as potent Ca(2+)-permeable AMPA receptor antagonists with non-hypotensive activity. Compound 10c showed selective Ca(2+)-permeable AMPA receptor antagonist activity and neuroprotective effects in transient global ischemia models in gerbils.

Inducible nitric oxide synthase expression and nuclear factor-kappaB activation in alveolar type II cells in lung injury.

Alveolar type II cells (type II cells) play a crucial role in the progression and repair of lung inflammation and injury. We investigated whether inducible nitric oxide synthase (iNOS) was expressed and nuclear factor-kappaB (NF-kappaB) was activated in type II cells in lung injury. After injecting lipopolysaccharide (LPS) or saline in the rat, the lungs were excised and type II cells were isolated. iNOS and its mRNA were expressed both in lung tissue and isolated type II cells in response to LPS. The lungs from saline-treated rats showed only minimal expression of iNOS. Electrophoretic mobility shift assay revealed that expression of NF-kappaB in the nuclear extracts was augmented by LPS, and p5O/NFkappaB was expressed in type II cells in LPS-treated rats. Intraperitoneal dexamethasone almost completely inhibited the iNOS expression and attenuated the activation of NF-kappaB in the LPS-treated lung. These findings suggest that type II cells can be a source of NO production in lung injury,and that the effects of corticosteroids may be in part through inhibition of both iNOS expression and NF-kappaB activation.

Beta1-adrenoceptor stimulation by high-dose terbutaline downregulates terbutaline-stimulated alveolar fluid clearance in ex vivo rat lung.

Because high-dose terbutaline and isoproterenol (10(-3) M), beta2-adrenergic agonists, failed to increase alveolar fluid clearance, the mechanisms responsible for this effect were examined in ex vivo rat lungs. An isosmolar 5% albumin solution with Evans blue dye was instilled into the distal airspaces in isolated rat lungs that were then inflated with 100% oxygen at an airway pressure of 8 cm H2O in a 37 degrees C incubator. Alveolar fluid clearance was measured by the progressive increase in dye concentrations over 1 hour. The results indicated that: (1) although 10(-5) M terbutaline or isoproterenol increased alveolar fluid clearance, 10(-3) M terbutaline or isoproterenol did not; (2) both concentrations of terbutaline (10(-5), 10(-3) M) increased intracellular adenosine 3',5'-cyclic monophosphate in cultured type II alveolar epithelial cells; (3) instillation of atenolol, a selective beta1-adrenergic antagonist, in the presence of either 10(-3) M terbutaline or isoproterenol was associated with an increase in alveolar fluid clearance. These results suggested that beta1-adrenoceptor stimulation prevented the normal response to a beta2-adrenergic agonist. To further test this hypothesis, a selective beta1-adrenergic agonist, denopamine, was administered; these results showed that (4) 10(-3) M denopamine, a selective beta1-adrenergic agonist, inhibited the increase in alveolar fluid clearance in the presence of 10(-5) M terbutaline; (5) hypoxia for 2 hours did not alter the effects of terbutaline on alveolar fluid clearance. The mechanism for the inability of the alveolar epithelium to respond to high-dose terbutaline or isoproterenol with the normal upregulation of alveolar fluid clearance in ex vivo rats lungs appears to be mediated by beta1-adrenoceptor stimulation that subsequently suppresses the beta2-adrenergic response.

Expression and localization of a novel Rab small G protein (Rab38) in the rat lung.

The Rab small G protein family participates in intracellular vesicle transport, including exocytosis and endocytosis. The cDNA encoding a novel Rab-related small G protein (Rab38) has been cloned from rat lung cDNA library and recorded in GenBank (accession no. M94043). However, the expression and localization of the protein in the lung remains primarily unknown. We produced polyhistidine-tagged recombinant Rab38 and a polyclonal antibody with a synthetic peptide. Immunohistochemistry demonstrated that the protein is specifically localized in alveolar type II cells and in bronchial epithelial cells. In situ hybridization using a digoxygenin-labeled RNA riboprobe clearly showed that the mRNA of the protein is localized in alveolar type II cells and bronchial epithelial cells, especially terminal airway epithelial cells. Western blot and reverse transcriptase-polymerase chain reaction showed distinct expression of the protein and mRNA in isolated alveolar type II cells, but not in alveolar macrophages. The native protein was predominantly hydrophobic and was enriched in a high-density vesicle fraction but was barely detectable in nuclear and lamellar body fractions in alveolar type II cells. Immunofluorescence cytochemistry performed on cultured alveolar type II cells showed that Rab38 distributed extensively in the cytoplasm with a distribution pattern similar to endoplasmic reticulum rather than other subcellular organelles. These results suggest that this novel rab small G protein (Rab38) mediates vesicular transport in terminal airway epithelium.

Beta1-adrenergic agonist is a potent stimulator of alveolar fluid clearance in hyperoxic rat lungs.

Because it was still uncertain whether a stimulation of beta1-adrenoceptors accelerated alveolar fluid clearance in hyperoxic lung injury, the effect of denopamine, a selective beta1-adrenergic agonist, on alveolar fluid clearance was determined in rats exposed to 93% oxygen for 48 and 56 h. Alveolar fluid clearance was measured by the progressive increase in the concentration of Evans blue labeled albumin instilled into the alveolar spaces over 1 h at 37 degrees C in isolated rat lungs. The principle results were as follows: 1) Although lung water volume increased in rats exposed to hyperoxia for 48 and 56 h, basal alveolar fluid clearance did not change for up to 56 h; 2) Denopamine increased alveolar fluid clearance in rats exposed to hyperoxia as well as in rats without exposure to hyperoxia; 3) Denopamine primarily increased amiloride-insensitive alveolar fluid clearance in rats exposed to hyperoxia; 4) The potency of denopmaine was similar to that of terbutaline, a selective beta2-adrenergic agonist. In summary, denopamine is a potent stimulator of alveolar fluid clearance in rats exposed to hyperoxia.

Pulmonary surfactant phosphatidylcholine transport bypasses the brefeldin A sensitive compartment of alveolar type II cells.

Brefeldin A (BFA) causes disassembly of the Golgi apparatus and blocks protein transport to this organelle from the endoplasmic reticulum. However, there still remains considerable ambiguity regarding the involvement of the Golgi apparatus in glycerolipid transport pathways. We examined the effects of BFA upon the intracellular translocation of phosphatidylcholine in alveolar type II cells, that synthesize, transport, store and secrete large amounts of phospholipid for regulated exocytosis. BFA at concentrations as high as 10 microg/ml failed to alter the assembly of phosphatidylcholine into lamellar bodies, the specialized storage organelles for pulmonary surfactant. The same concentration of BFA was also ineffective at altering the secretion of newly synthesized phosphatidylcholine from alveolar type II cells. In contrast, concentrations of the drug of 2.5 microg/ml completely arrested newly synthesized lysozyme secretion from the same cells, indicating that BFA readily blocked protein transport processes in alveolar type II cells. The disassembly of the Golgi apparatus in alveolar type II cells following BFA treatment was also demonstrated by showing the redistribution of the resident Golgi protein MG-160 to the endoplasmic reticulum. These results indicate that intracellular transport of phosphatidylcholine along the secretory pathway in alveolar type II cells proceeds via a BFA insensitive route and does not require a functional Golgi apparatus.

Denopamine, a beta(1)-adrenergic agonist, increases alveolar fluid clearance in ex vivo rat and guinea pig lungs.

The effect of denopamine, a selective beta(1)-adrenergic agonist, on alveolar fluid clearance was determined in both ex vivo rat and guinea pig lungs. Alveolar fluid clearance was measured by the progressive increase in the concentration of Evans blue-labeled albumin over 1 h at 37 degrees C. Denopamine (10(-6) to 10(-3) M) increased alveolar fluid clearance in a dose-dependent manner in ex vivo rat lungs. Denopamine also stimulated alveolar fluid clearance in guinea pig lungs. Atenolol, a selective beta(1)-adrenergic antagonist, and amiloride, a sodium channel inhibitor, inhibited denopamine-stimulated alveolar fluid clearance. The potency of denopamine was similar to that of similar doses of isoproterenol or terbutaline. Short-term hypoxia (100% nitrogen for 1-2 h) did not alter the stimulatory effect of denopamine. Denopamine (10(-4), 10(-3) M) increased intracellular adenosine 3',5'-cyclic monophosphate levels in cultured rat alveolar type II cells. In summary, denopamine, a selective beta(1)-adrenergic agonist, stimulates alveolar fluid clearance in both ex vivo rat and guinea pig lungs.

Lung deflation impairs alveolar epithelial fluid transport in ischemic rabbit and rat lungs.

BACKGROUND: Because the fluid transport capacity of the alveolar epithelium after lung ischemia with and without lung deflation has not been well studied, we carried out experimental studies to determine the effect of lung deflation on alveolar fluid clearance. METHODS: After 1 or 2 hr of ischemia, we measured alveolar fluid clearance using 125I-albumin and Evans blue-labeled albumin concentrations in in vivo rabbit lungs in the presence of pulmonary blood flow and in ex vivo rat lungs in the absence of any pulmonary perfusion, respectively. RESULTS: The principal results were: (1) lung deflation decreased alveolar fluid clearance while inflation of the lungs during ischemia preserved alveolar fluid clearance in both in vivo and ex vivo studies; (2) alveolar fluid clearance was normal in the rat lungs inflated with nitrogen (thus, alveolar gas composition did not affect alveolar fluid clearance); (3) amiloride-dependent alveolar fluid clearance was preserved when the lungs were inflated during ischemia; (4) terbutaline-simulated alveolar fluid clearance was preserved in the hypoxic rat lungs inflated with nitrogen; (5) lecithinized superoxide dismutase, a scavenger of superoxide anion, and N(omega)-nitro-L-arginine methyl ester, an inhibitor of nitric oxide, preserved normal alveolar fluid clearance in the deflated rat lungs. CONCLUSION: Lung deflation decreases alveolar fluid clearance by superoxide anion- and nitric oxide-dependent mechanisms.

[Lung tissue injury caused by oxidant-antioxidant imbalance].

The lung is susceptive to excess oxidants from inhaled air and marginated large portion of circulating leukocytes. Oxygen radicals generated from sequestrated leukocytes injure endothelial cells to increase permeability. Excessively generated oxidants in the mitochondria, such as in ischemia-reperfusion injury, changes mitochondrial function and cause Ca++ leak from the organelle, which leads to induction of apoptosis. Reactive oxygen intermediates induce some cytokine gene expression such as IL-8. Hydrogen peroxide activates phospholipase C and the subsequent signal transduction pathways resulting in change of cytoskeletal configuration and cell shape. It is expected that understanding of contribution of oxidant-antioxidant imbalance in lung diseases may develop new strategy of 'antioxidant' therapies.

Effects of interleukin-1 beta on DNA synthesis in rat alveolar type II cells in primary culture.

Proliferation of alveolar type II cells is critical for restoration of the integrity of alveolar epithelium in alveolar injuries caused by a number of different aetiologies. Because effects of inflammatory cytokines on the proliferation of alveolar type II cells are not clear, we investigated the effects of interleukin-1 beta (IL-1 beta) on [3H]-thymidine incorporation into DNA in rat alveolar type II cells in primary culture. Interleukin-1 beta enhanced the [3H]-thymidine incorporation dose and time dependently. The increase of [3H]-thymidine incorporation was observed in parallel with increased number of rat alveolar type II cells. The effect of IL-1 beta on [3H]-thymidine incorporation was additive to effects of growth factors which were known to act as mitogenic factors for type II cells. Anti-interleukin-1 beta antibody or IL-1 receptor antagonist partially inhibited the effects of IL-1 beta on [3H]-thymidine incorporation. Their combination completely inhibited the effects of IL-1 beta. In the absence of IL-1 beta, the combination inhibited the [3H]-thymidine incorporation to a level under that in the control. Isolated alveolar type II cells were immunocytochemically stained positive with anti-IL-1 beta antibody. Reverse transcriptase-polymerase chain reaction (RT-PCR) showed the presence of the mRNA for IL-1 beta in cultured alveolar type II cells. These results demonstrate that exogenous IL-1 beta stimulates DNA synthesis in alveolar type II cells and that the cells also produce IL-1 beta endogenously and suggest that endogenous IL-1 beta may mediate basal DNA synthesis of alveolar type II cells.

Trafficking of newly synthesized surfactant protein A in isolated rat alveolar type II cells.

We examined the synthesis, transport, and localization of surfactant protein A (SP-A) in primary cultures of alveolar type II cells. In type II cells maintained in culture for 6 h, 39% of the SP-A pool detected with an enzyme-linked immunosorbent assay (ELISA) was found in lamellar bodies (LBs). After 24 h in culture, 53% of the cellular SP-A pool was found in LBs. The absolute amount of SP-A in the LB compartment was almost identical at 6 and 24 h of culture. In contrast to the results obtained with ELISA, 35S labeling of newly synthesized SP-A revealed that less than 7% of the cellular SP-A pool was in LBs at either 6 or 24 h of culture. In the 6-h cultures, 17% of the total (i.e., cells and media) [35S]SP-A pool was extracellular. In the 24-h cultures, 70% of the [35S]SP-A pool was extracellular. The secretion of [35S]SP-A was blocked by brefeldin A at all times. When medium containing newly secreted [35S]SP-A was incubated with alveolar type II cells maintained in culture for 24 h, the protein was taken up and incorporated into the LB fraction. More than 80% of the internalized SP-A was associated with the LB compartment after a 6 h incubation. The uptake of [35S]SP-A was blocked at 4 degrees C and was promoted by addition of unlabeled SP-A at 37 degrees C. These findings support a pathway of extracellular routing of SP-A prior to its accumulation in LBs in cultured type II cells.

Extracellular Ca2+ entry and Ca2+ release from inositol 1,4,5-trisphosphate-sensitive stores function at fertilization in oocytes of the marine bivalve Mytilus edulis.

An oocyte of the marine bivalve Mytilus edulis, which is arrested at metaphase I, reinitiates meiosis at fertilization. The fertilized oocyte shows increases in intracellular Ca2+ ([Ca2+]i) comprising three different phases: an initial large [Ca2+]i transient, a subsequent low but sustained [Ca2+]i elevation, and repetitive small [Ca2+]i transients. In this study, we have investigated the sources and mechanisms of the sperm-induced [Ca2+]i increases. Application of methoxyverapamil (D-600), an inhibitor of voltage-dependent Ca2+ influx, suppressed the initial [Ca2+]i transient but did not affect the following two phases of [Ca2+]i changes. Injection of heparin, an antagonist of the inositol 1,4,5-trisphosphate (IP3) receptor, inhibited the later two phases without much affecting the initial transient. Combined application of D-600 and heparin almost completely abolished the three phases of the sperm-induced [Ca2+]i changes. Furthermore, Ca2+ influx caused by seawater containing excess K+ was blocked by D-600 but not by heparin, and IP3-induced Ca2+ release caused by photolysis of injected 'caged' derivatives of IP3 was blocked by heparin but not by D-600. These results strongly suggest that two types of Ca2+ mobilization systems, the extracellular Ca2+ entry responsible for an initial [Ca2+]i transient and the IP3 receptor-mediated Ca2+ release responsible for the following two phases of [Ca2+]i changes, function at fertilization of Mytilus oocytes.

Serotonin-induced meiosis reinitiation from the first prophase and from the first metaphase in oocytes of the marine bivalve Hiatella flaccida: respective changes in intracellular Ca2+ and pH.

In the marine bivalve Hiatella flaccida, full-grown oocytes in ovaries are arrested at the first prophase (prophase-I) of meiosis, whereas spawned oocytes have reinitiated meiosis from prophase-I and are again arrested at the first metaphase (metaphase-I). The neurohormone serotonin (5-hydroxytryptamine, 5-HT) was able to trigger meiosis reinitiation both from prophase-I and from metaphase-I. Exposure of prophase-I oocytes to 5-HT caused an increase in intracellular Ca2+ ([Ca2+]i) composed of an initial towering transient and a following lower but sustained elevation. 5-HT-stimulated prophase-I oocytes also showed a gradual rise in intracellular pH (pHi), reaching a plateau level. None of these 5-HT-induced responses was affected by the complete absence of external Ca2+. On the other hand, these responses were suppressed by preinjection of heparin, an antagonist of inositol 1,4,5-trisphosphate-sensitive receptors. Metaphase-I oocytes also exhibited a [Ca2+]i increase in response to 5-HT; the initial [Ca2+]i transient was larger than that in prophase-I oocytes when stimulated with the same 5-HT concentration. Furthermore, after the initial transient, the elevated [Ca2+]i was not sustained but sometimes returned to the prestimulus level and then increased again. Metaphase-I oocytes had higher resting pHi levels than prophase-I oocytes and showed no significant pHi changes after addition of 5-HT. These results suggest that both a [Ca2+]i increase and a pHi rise are responsible for the release from prophase-I arrest, while a [Ca2+]i increase alone is concerned with the release from metaphase-I arrest.

Existence of Three Mechanisms for Blocking Polyspermy in Oocytes of the Mussel Mytilus edulis.

We found the existence of a three-step mechanism to block polyspermy in the oocyte of the mussel Mytilus edulis. When the oocytes were inseminated within 30 min after spawning, they underwent monospermic fertilization over a wide range of sperm-oocyte ratios up to 5 x 103. A transient depolarization of the oocyte plasma membrane (fertilization potential) was observed immediately after insemination. Low-sodium seawater induced polyspermy and decreased the amplitude of the fertilization potential, suggesting the existence of a fast block to polyspermy that is dependent on depolarization of the plasma membrane. When the fertilized oocytes were inseminated again at a sperm-oocyte ratio that is great enough to give a high rate of polyspermy in initial insemination, many sperm could not undergo the acrosomal reaction and thus could not penetrate fertilized oocytes. The remaining sperm underwent an acrosomal reaction and the acrosomal process protruded through the vitelline coat, but it did not fuse with the oocyte plasma membrane. These findings suggest the existence of two strategies constituting a late polyspermy block: suppression of acrosomal reaction and block of contact or fusion between the plasma membranes of sperm and oocyte.

Meiosis reinitiation from the first prophase is dependent on the levels of intracellular Ca2+ and pH in oocytes of the bivalves Mactra chinensis and Limaria hakodatensis.

Naturally spawned oocytes of the marine bivalves Mactra chinensis and Limaria hakodatensis are arrested at the first prophase (prophase-I) and the first metaphase, respectively, until fertilization. Using the Ca2+ indicator fura-2 and the pH indicator 1-hydroxypyrene-3,6,8-trisulfonic acid, we have examined the respective effects of intracellular Ca2+ ([Ca2+]i) and pH (pHi) on meiosis reinitiation from prophase-I in oocytes of the two species. Shortly after insemination, Mactra oocytes displayed a transient [Ca2+]i increase followed by a period of sustained [Ca2+]i elevation. Removal of external Ca2+ shortly after fertilization immediately decreased the elevated [Ca2+]i to the resting level and inhibited germinal vesicle breakdown (GVBD); 100% GVBD was obtained when elevated [Ca2+]i above the threshold level (F340/F380: approximately 0.55) was kept for at least 5 min. Fertilized Mactra oocytes also showed a gradual pHi rise; sperm-induced GVBD was blocked when pHi was maintained below the threshold level (F450/F380: approximately 0.95) by adding ammonia and acetate to the bath after insemination. In contrast, 2 mM ammonia caused a pHi rise and GVBD in Limaria oocytes without much affecting the [Ca2+]i level. For obtaining 100% GVBD, pHi had to be maintained for at least 5 min above the threshold level (F450/F380: approximately 0.9), which is similar to that in Mactra. Resting [Ca2+]i levels (F340/F380: approximately 0.65) in Limaria prophase-I oocytes were higher than the threshold level for GVBD in fertilized Mactra oocytes. It is possible that maintenance of both [Ca2+]i and pHi above threshold levels are required for GVBD and the levels are about the same in Mactra and Limaria, assuming that spectral characteristics of the indicators are the same in oocytes of the two species.

Cytochalasin B does not block sperm penetration into denuded starfish oocytes.

During fertilisation in starfish oocytes, the fertilisation cone develops temporarily beneath the penetrating sperm. The role of the fertilisation cone in sperm incorporation in the starfish Asterias amurensis was examined using cytochalasin B (CB). CB (2 microM) allowed sperm acrosomal process-egg plasma membrane fusion and egg activation, but inhibited the development of the fertilisation cone containing actin microfilaments. When sperm were added to intact oocytes (with the jelly coat and vitelline coat) in seawater containing CB, the sperm head did not penetrate the fertilisation membrane. Although the acrosomal process fused with egg plasma membrane, the sperm head remained outside the fertilisation membrane. On the other hand, denuded oocytes without the jelly coat and vitelline coat allowed sperm penetration even in the presence of 2 microM CB. Electron microscopy revealed that sperm organelles, including the acrosomal process, nucleus, mitochondrion and tail, were incorporated into the slightly electron-dense cytoplasm, which was similar to the cytoplasm of the fertilisation cone. These results show that the development of the fertilisation cone/actin filament complex is not essential for incorporation of the sperm, since incorporation can occur in denuded oocytes. However, the cone is required for fertilisation of intact oocytes, suggesting that this actin-filament-containing structure is necessary for getting the sperm through the outer egg coats.

Repetitive intracellular Ca2+ increases at fertilization and the role of Ca2+ in meiosis reinitiation from the first metaphase in oocytes of marine bivalves.

Spawned oocytes of marine bivalves Limaria hakodatensis, Mytilus edulis, Crassostrea gigas, and Hiatella flaccida are arrested at the first metaphase (metaphase-I) until fertilization. We have measured changes in intracellular Ca2+ ([Ca2+]i) at fertilization in the single oocytes of these bivalves using the fluorescent Ca2+ indicator fura-2. Shortly after insemination, these oocytes displayed a transient [Ca2+]i increase which was usually followed by a period during which [Ca2+]i was kept higher than the resting level (elevated [Ca2+]i period). During this period, [Ca2+]i showed oscillatory increases superimposed on an elevated [Ca2+]i level in Limaria, Crassostrea, and Hiatella, whereas a sustained elevation without pulses occurred in Mytilus. After [Ca2+]i returned to the resting level, repetitive transient [Ca2+]i increases appeared in Limaria, Mytilus, and Hiatella. The [Ca2+]i increases still occurred following external Ca2+ removal shortly after fertilization in all four bivalve species. In contrast, external Ca2+ removal immediately abolished a [Ca2+]i increase induced by excess-K+ seawater in Mytilus. Using another fluorescent Ca2+ indicator, calcium green, we found that during the first transient in Mytilus, [Ca2+]i increased uniformly over the whole oocyte. These results strongly suggest that the fashion of [Ca2+]i increases at fertilization in bivalve oocytes fertilized at metaphase-I differs not only from that in deuterostomes but also from that in protostomes oocytes of which are fertilized at the first prophase.

[Spontaneously healed P. carinii pneumonia in the course of steroid therapy for interstitial pneumonia--many trophozoites in bronchoalveolar lavage].

A case in which P. carinii was observed in bronchoalveolar lavage fluid during steroid therapy for interstitial pneumonia in a 63-year-old man is reported, he had received steroid therapy for interstitial pneumonia of unknown origin. Three weeks later, he developed acute pneumonia with Streptococcus pneumoniae, and simultaneously P. carinii was detected in the bronchoalveolar lavage fluid. Both the pneumonic shadows and P. carinii disappeared following intravenous infusion of penicillin and rapid reduction of steroid. Electron microscopic analysis of P. carinii demonstrated numerous tubular expansions and endogenies of P. carinii, suggesting that P. carinii was growing in the intra-alveolar spaces. Phospholipid analysis demonstrated a transient increase in total phospholipid content during P. carinii pneumonia, suggesting that P. carinii can affect surfactant metabolism.