Trafficking of newly synthesized surfactant protein B to the lamellar body in alveolar type II cells

Lung surfactant accumulates in the lamellar body (LB) via not only the secretory (anterograde) pathway but also the endocytic (retrograde) pathway. Our previous studies suggested that the major surfactant components, phosphatidylcholine and surfactant protein A take independent trafficking routes in alveolar type II cells. Thus, trafficking of surfactant protein B (SP-B), a major hydrophobic surfactant apoprotein, should be re-evaluated by a straightforward method. Radiolabeling of cells and subsequent cell fractionation were employed to pursue the sequential trafficking of newly synthesized SP-B in rabbit alveolar type II cells. The LB fraction was prepared by gradient ultracentrifugation. Immunoprecipitation from the culture medium, total cells, and LB fraction was carried out with anti-SP-B antibody. Newly synthesized [³⁵S]-pro-SP-B (~ 42 kDa) was detected in the cells after 1 h. An ~ 8-kDa mature form of [³⁵S]-SP-B was detected in the cells after 3 h and in the LB after 6 h. Mature [³⁵S]-SP-B was predominant in the cells after 24 h, and the dominant portion was present in the LB. In contrast, only a small amount of mature [³⁵S]-SP-B was present in the culture medium. Molecular processing of ~ 42 kDa [³⁵S]-pro-SP-B and transport to the LB was inhibited by brefeldin A, which disassembles the Golgi apparatus. These results suggest that newly synthesized SP-B is sorted to the LB via the Golgi and stored until exocytosis. This pathway is distinct from the pathways reported for phosphatidylcholine and surfactant protein A.

A case of ROS1-rearranged lung adenocarcinoma with osteoblastic bone metastasis

A 53-year-old woman was referred to our hospital for detailed examination of abnormal chest shadows recognized on CT imaging. Transbronchial lung biopsy of a right S6 nodular shadow led to a diagnosis of lung adenocarcinoma. FDG-PET-CT showed FDG accumulation in the Th11 and L2 vertebral bodies and osteoblastic bone lesions. Since osteoblastic bone metastasis in lung cancer is extremely rare, CT-guided bone biopsy was performed. The tumor was diagnosed as ROS1-rearranged lung adenocarcinoma, for which crizotinib was administered, which led to improvement of both the primary and metastatic lesions. We report here a rare case of ROS1-rearranged lung adenocarcinoma with osteoblastic bone metastasis of lung cancer.

Rab38 Mutation and the Lung Phenotype

Rab38 is highly expressed in alveolar type II cells, melanocytes, and platelets. These cells are specifically-differentiated cells and contain characteristic intracellular organelles called lysosome-related organelles, i.e., lamellar bodies in alveolar type II cells, melanosomes in melanocytes, and dense granules in platelets. There are Rab38-mutant rodents, i.e., chocolate mice and Ruby rats. While chocolate mice only show oculocutaneous albinism, Ruby rats show oculocutaneous albinism and prolonged bleeding time and, hence, are a rat model of Hermansky-Pudlak syndrome (HPS). Most patients with HPS suffer from fatal interstitial pneumonia by middle age. The lungs of both chocolate mice and Ruby rats show remarkably increased amounts of lung surfactant and conspicuously enlarged lysosome-related organelles, i.e., lamellar bodies, which are also characteristic of the lungs in human HPS. There are 16 mutant HPS-mouse strains, of which ten mutant genes have been identified to be causative in patients with HPS thus far. The gene products of eight of the ten genes constitute one of the three protein complexes, i.e., biogenesis of lysosome-related organelle complex-1, -2, -3 (BLOC-1, -2, -3). Patients with HPS of the mutant BLOC-3 genotype develop interstitial pneumonia. Recently, BLOC-3 has been elucidated to be a guanine nucleotide exchange factor for Rab38. Growing evidence suggests that Rab38 is an additional candidate gene of human HPS that displays the lung phenotype.

ADRB2 gene polymorphism and emphysema heterogeneity can modulate bronchodilator response in patients with emphysema

BACKGROUND

Genetic variation in the β₂-adrenergic receptor (ADRB2) gene has been thought to have an important role in the differential response to β₂-agonist therapy for asthma. However, previous studies have shown little evidence for an association between these ADRB2 variants and the bronchial dilator response (BDR) in chronic obstructive pulmonary disease (COPD) patients. This discrepancy could be explained by differences in the distribution and heterogeneity of pulmonary emphysema in COPD patients, since emphysema distribution and heterogeneity are thought to have a role in pulmonary function in COPD patients. We hypothesized that differences in emphysema distribution and heterogeneity may have masked significant alterations of the bronchodilator response among ADRB2 genotypes in COPD patients in previous studies.

METHODS

The BDR (induced by 20 μg of procaterol) was measured in 211 patients who had a smoking history of more than 10 pack/years and had undergone chest high resolution computed tomography examination. A low attenuations area (<960 Hounsfield Units) was identified and the emphysema heterogeneity index (EHI%) was calculated with a range in value from -100% to 100%. ADRB2 Arg16Gly genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism analysis.

RESULTS

The BDR was augmented in patients with homogenous emphysema compared with those with upper-dominant emphysema. In patients carrying the AA genotype of ADRB2, the BDR was significantly increased in patients with upper-dominant emphysema, but not in patients with lower-dominant emphysema.

CONCLUSION

Combination analysis of ADRB2 Arg16Gly polymorphism and EHI% may predict the effectiveness of β₂-adrenergic receptor agonist treatment in patients with COPD and emphysema.

Exogenous gene transfer of Rab38 small GTPase ameliorates aberrant lung surfactant homeostasis in Ruby rats

Background

Rab³8 small GTPase regulates intracellular transport in melanocytes and alveolar type II epithelial cells. Ruby rats carrying Rab³8 and other gene mutations exhibit oculocutaneous albinism, bleeding diathesis, and hence, are a rat model of human Hermansky-Pudlak syndrome (HPS). We previously showed that Long Evans Cinnamon (LEC) rats, one strain of the Ruby rats, developed aberrant lung surfactant homeostasis with remarkably enlarged lamellar bodies in alveolar type II cells.

Methods

A replication-deficient recombinant adenovirus expressing rat Rab³8 (Ad-Rab³8) was constructed. Alveolar type II cells were isolated from the LEC rats and tested for lung surfactant phosphatidylcholine secretion. The rats were also examined whether exogenous expression of Ad- Rab³8 could rescue the altered lung surfactant homeostasis in the lungs.

Results

Isolated type II cells infected with Ad-Rab³8 exhibited improved secretion patterns of [³H]phosphatidylcholine, i.e. increased basal hyposecretion and decreased agonist-induced hypersecretion. Endobronchial administration of Ad-Rab³8 improved the morphology of type II cells and lamellar bodies, reducing their sizes close to those of wild-type rats. The increased amounts of phosphatidylcholine and surfactant protein B in the lamellar body fractions were decreased in the Ad-Rab³8 infected lungs.

Conclusions

These results provide strong evidence that the aberrant lung surfactant homeostasis in the LEC rats is caused by Rab³8 deficit, and suggest that endobronchial delivery of the responsive transgene could be an effective method to ameliorate the abnormal lung phenotype in the animal model of HPS.

p53 Signaling Pathway Polymorphisms Associated With Emphysematous Changes in Patients With COPD

BACKGROUND

The p53 signaling pathway may be important for the pathogenesis of emphysematous changes in the lungs of smokers. Polymorphism of p53 at codon 72 is known to affect apoptotic effector proteins, and the polymorphism of mouse double minute 2 homolog (MDM2) single nucleotide polymorphism (SNP)309 is known to increase MDM2 expression. The aim of this study was to assess polymorphisms of the p53 and MDM2 genes in smokers and confirm the role of SNPs in these genes in the pathogenesis of pulmonary emphysema.

METHODS

This study included 365 patients with a smoking history, and the polymorphisms of p53 and MDM2 genes were identified. The degree of pulmonary emphysema was determined by means of CT scanning. SNPs, MDM2 mRNA, and p53 protein levels were assessed in human lung tissues from smokers. Plasmids encoding p53 and MDM2 SNPs were used to transfect human lung fibroblasts (HLFs) with or without cigarette smoke extract (CSE), and the effects on cell proliferation and MDM2 promoter activity were measured.

RESULTS

The polymorphisms of the p53 and MDM2 genes were associated with emphysematous changes in the lung and were also associated with p53 protein and MDM2 mRNA expression in the lung tissue samples. Transfection with a p53 gene-coding plasmid regulated HLF proliferation, and the analysis of P2 promoter activity in MDM2 SNP309-coding HLFs showed the promoter activity was altered by CSE.

CONCLUSIONS

Our data demonstrated that p53 and MDM2 gene polymorphisms are associated with apoptotic signaling and smoking-related emphysematous changes in lungs from smokers.

Lentiviral vector-mediated delivery of lysophosphatidylcholine acyltransferase 1 attenuates airway inflammation in ovalbumin-induced allergic asthmatic mice

BACKGROUND

Lysophosphatidylcholine (LPC) is generated through the hydrolysis of phospha-tidylcholine (PC) by phospholipase A2 and is converted back to PC by lysophosphatidylcholine acyltransferase 1 (LPCAT1). Elevated levels of (LPC) are known to play a pathogenic role in the inflammatory injury of asthma. However, the role of LPCAT1 in asthma has not yet been reported.

OBJECTIVE

To determine whether the exogenous expression of LPCAT1, delivered by using a recombinant lentiviral vector, could attenuate airway inflammation in asthmatic mice.

METHODS

Recombinant lentivirus carrying cDNA encoding LPCAT1 (Lenti-LPCAT1), or EGFP (Lenti-EGFP) as a control, was constructed. BALB/c mice were sensitised with ovalbumin (OVA), and intratracheally pre-treated with an endobronchial administration of the recombinant lentivirus intratracheally 72 hours before the first challenge. After the last OVA challenges, the mice were assessed for airway inflammation, airway hyper-responsiveness and lipid levels.

RESULTS

Lenti-LPCAT1-infected HEK293T cells expressed exogenous recombinant LPCAT1 protein that showed high activity of the LPC acyltransferase. OVA sensitisation and challenge significantly increased the levels of saturated species LPC 16:0 and LPC 18:0 levels in the bronchoalveolar lavage fluid (BALF) compared with wild-type mice respectively. The intratracheal Lenti-LPCAT1 instillation obviously down-regulated the OVA-induced release of LPC 16:0 and LPC 18:0. Treatment with Lenti-LPCAT1 ameliorated OVA-induced airway hyper-responsiveness and reduced airway eosinophilia infiltration in lung tissue. Furthermore, the secretion of eotaxin and Th2-associated cytokines IL-5 and IL-13 were inhibited in BALF. The level of OVA-specific IgE in serum was suppressed.

CONCLUSIONS

These results suggested that the exogenous expression of LPCAT1 may attenuate eosinophil inflammation in the airway by down-regulating the LPC 16:0 and LPC 18:0 BALF levels in asthmatic mice.

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.

A three-microphone acoustic reflection technique using transmitted acoustic waves in the airway

The acoustic reflection technique noninvasively measures airway cross-sectional area vs. distance functions and uses a wave tube with a constant cross-sectional area to separate incidental and reflected waves introduced into the mouth or nostril. The accuracy of estimated cross-sectional areas gets worse in the deeper distances due to the nature of marching algorithms, i.e., errors of the estimated areas in the closer distances accumulate to those in the further distances. Here we present a new technique of acoustic reflection from measuring transmitted acoustic waves in the airway with three microphones and without employing a wave tube. Using miniaturized microphones mounted on a catheter, we estimated reflection coefficients among the microphones and separated incidental and reflected waves. A model study showed that the estimated cross-sectional area vs. distance function was coincident with the conventional two-microphone method, and it did not change with altered cross-sectional areas at the microphone position, although the estimated cross-sectional areas are relative values to that at the microphone position. The pharyngeal cross-sectional areas including retropalatal and retroglossal regions and the closing site during sleep was visualized in patients with obstructive sleep apnea. The method can be applicable to larger or smaller bronchi to evaluate the airspace and function in these localized airways.

[Cytokines and proteases involved in pathogenesis of COPD]

COPD is characterized by persistence of chronic inflammation in small airways and alveoli. Macrophages, neutrophils, and a specialized subset of T lymphocytes orchestrate the mild inflammation. This article focuses on humoral factors such as cytokines and chemokines that recruit these inflammatory and immune cells to the lungs, and proteases/antiproteases that ultimately cause structural derangement in the terminal respiratory zones. In addition to the classical protease and antiprotease imbalance hypothesis, alveolar homeostasis abnormality that comes from imbalance of lung constitutional cell apoptosis and regeneration may play a role in emphysema development. Also, autoimmunity to elastin degradation products may take part in the disease.

Altered lung surfactant system in a Rab38-deficient rat model of Hermansky-Pudlak syndrome

Several Long-Evans rat substrains carrying the phenotype of oculocutaneous albinism and bleeding diathesis are a rat model of Hermansky-Pudlak syndrome (HPS). The mutation responsible for the phenotype ( Ruby) was identified as a point mutation in the initiation codon of Rab38 small GTPase that regulates intracellular vesicle transport. As patients with HPS often develop life-limiting interstitial pneumonia accompanied by abnormal morphology of alveolar type II cells, we investigated lung surfactant system in Long-Evans Cinnamon rats, one strain of the Ruby rats. The lungs showed conspicuous morphology of type II cells containing markedly enlarged lamellar bodies. Surfactant phosphatidylcholine and surfactant protein B were increased in lung tissues and lamellar bodies but not in alveolar lumen. Expression levels of mRNA for surfactant proteins A, B, C, and D were not altered. Isolated type II cells showed aberrant secretory pattern of newly synthesized [3H]phosphatidylcholine, i.e., decreased basal secretion and remarkably amplified agonist-induced secretion. [3H]phosphatidylcholine synthesis and uptake by type II cells were not altered. Thus Rab38-deficient type II cells appear to carry abnormality in lung surfactant secretion but not in synthesis or uptake. These results suggest that aberrant lung surfactant secretion may be involved in the pathogenesis of interstitial pneumonia in HPS.

A mutation in Rab38 small GTPase causes abnormal lung surfactant homeostasis and aberrant alveolar structure in mice

The chocolate mutation, which is associated with oculocutaneous albinism in mice, has been attributed to a G146T transversion in the conserved GTP/GDP-interacting domain of Rab38, a small GTPase that regulates intracellular vesicular trafficking. Rab38 displays a unique tissue-specific expression pattern with highest levels present in the lung. The purpose of this study was to characterize the effects of Rab38-G146T on lung phenotype and to investigate the molecular basis of the mutant gene product (Rab38(cht) protein). Chocolate lungs exhibited a uniform enlargement of the distal airspaces with mild alveolar destruction as well as a slight increase in lung compliance. Alveolar type II cells were engorged with lamellar bodies of increased size and number. Hydrophobic surfactant constituents (ie, phosphatidylcholine and surfactant protein B) were increased in lung tissues but decreased in alveolar spaces, consistent with a malfunction in lamellar body secretion and the subsequent cellular accumulation of these organelles. In contrast to wild-type Rab38, native Rab38(cht) proteins were found to be hydrophilic and not bound to intracellular membranes. Unexpectedly, recombinant Rab38(cht) proteins retained GTP-binding activity but failed to undergo prenyl modification that is required for membrane-binding activity. These results suggest that the genetic abnormality of Rab38 affects multiple lysosome-related organelles, resulting in lung disease in addition to oculocutaneous albinism.

[Case of broncholithiasis lithoptysis occurring spontaneously after repeated pneumonia]

An abnormal chest shadow was pointed out in a 56-year-old woman in a health check in 2001. She had pulmonary tuberculosis at age 11. Because of repeated fever for the previous 2 years, she visited our hospital in 2003 and right upper lobe pneumonia was detected with a calcified nodule that completely obstructed the right upper lobe bronchus on CT. After admission, she spontaneously expectorated a stone. The composition of the stone was 57% calcium phosphate and 43% calcium carbonate. Radiological findings and the composition of the stone suggested that this broncholith was calcified bronchial mucus rather than a calcified lymph node that might have perforated into the airway. Bronchiectasis of the right B3 broncus was observed on CT scan after lithoptysis. Although the bronchiectasis was unchanged 2 years later, she had no symptoms, such as fever or cough.

Melanocyte differentiation antigen RAB38/NY-MEL-1 induces frequent antibody responses exclusively in melanoma patients

Expression pattern and immunogenicity are critical issues that define tumor antigens as diagnostic markers and potential targets for immunotherapy. The development of SEREX (serological analysis of recombinant expression libraries) has provided substantial progress in the identification of tumor antigens eliciting both cellular and humoral immune responses in cancer patients. By SEREX, we have previously identified RAB38/NY-MEL-1 as a melanocyte differentiation antigen that is highly expressed in normal melanocytes and melanoma tissues but not in other normal tissues or cancer types. In this study, we further demonstrate that RAB38/NY-MEL-1 is strongly immunogenic, leading to spontaneous antibody responses in a significant proportion of melanoma patients. The immune response occurs solely in malignant melanoma patients and was not detected in patients with other diseases, such as vitiligo, affecting melanocytes. Fine analysis of the spontaneous anti-RAB38/NY-MEL-1 antibody response reveals a polyclonal B cell recognition targeting various epitopes, although a dominant immunogenic region was preferentially recognized. Interestingly, our data indicate that this recognition is not rigid in the course of a patient's response, as the dominant epitope changes during the disease evolution. Implications for the understanding of spontaneous humoral immune responses are discussed.

Stimulation of alveolar epithelial fluid clearance in human lungs by exogenous epinephrine

OBJECTIVES

Because several experimental studies have demonstrated that cyclic adenosine monophosphate generation following beta-adrenoceptor activation can markedly stimulate alveolar fluid clearance, we determined whether the endogenous levels of catecholamines that occur in the pulmonary edema fluid and plasma of patients with acute lung injury are high enough to stimulate alveolar fluid clearance in the human lung.

DESIGN

Observational clinical study.

SETTING

Academic university hospital and laboratory.

PATIENTS

Twenty-one patients with acute pulmonary edema plus ex vivo human lungs.

INTERVENTIONS

Measurements of catecholamine levels in patient samples and controlled laboratory studies of the effects of these catecholamine levels on the rates of alveolar fluid clearance in ex vivo human lungs.

MEASUREMENTS AND MAIN RESULTS

The concentrations of both epinephrine and norepinephrine in the pulmonary edema fluid and plasma were approximately 10 M (range of 1-8x10 M) in hydrostatic pulmonary edema (n=6) and acute lung injury patients (n=15). We therefore tested whether 10 M epinephrine or norepinephrine stimulated alveolar fluid clearance in isolated human lungs and found that these epinephrine or norepinephrine concentrations did not stimulate alveolar fluid clearance. However, higher concentrations of epinephrine (10 M), but not norepinephrine (10 M), significantly stimulated alveolar fluid clearance by 84% above control. Glibenclamide (10 M) and CFTRinh-172 (10 M), cystic fibrosis transmembrane conductance regulator inhibitors, completely inhibited the epinephrine-induced stimulation of alveolar fluid clearance.

CONCLUSIONS

These results indicate that endogenous catecholamine concentrations in pulmonary edema fluid are probably not sufficient to stimulate alveolar fluid clearance. In contrast, administration of exogenous catecholamines into the distal airspaces can stimulate alveolar fluid clearance in the human lung, an effect that is mediated in part by cystic fibrosis transmembrane conductance regulator. Therefore, exogenous cyclic adenosine monophosphate-dependent stimulation will probably be required to accelerate the resolution of alveolar edema in the lungs of patients with pulmonary edema.

Pulmonary surfactant transport in alveolar type II cells

Pulmonary surfactant (PS) is a mixture of several lipids (mainly phosphatidylcholine; PC) and four apoproteins (A, B, C and D). The classical hypothesis of PS transport suggests that PS is synthesized in the endoplasmic reticulum and transported to the lamellar body (LB) via the Golgi apparatus. However, recent studies have raised questions regarding this single route. This study examined, independently, the intracellular trafficking route of three different components of PS, that is, PC, SP-A and SP-B. Alveolar type II cells were isolated from Sprague-Dawley rats or Japanese white rabbits. The cells were cultured with either [3H]choline or [35S]methionine/cysteine with or without brefeldin A, which disassembles the Golgi apparatus. LB was purified from disintegrated cells with sucrose density gradient centrifugation. [3H]PC was extracted from radiolabeled media, cells, and the LB fraction with Bligh-Dyer's method. [35S]SP-A or [35S]SP-B was immunoprecipitated from each sample with a specific antibody. [3H]PC was transported and stored to the LB via a Golgi-independent pathway. [35S]SP-A was transported to the Golgi apparatus, underwent glycosylation, and was then constitutively secreted. The secreted [35S]SP-A was re-uptaken into the LB. [35S]SP-B was transported and stored to the LB via the Golgi-dependent pathway. These results indicate that, rather than a single route, surfactant components take different pathways to reside in the LB. These different pathways may reflect the different nature and role of each surfactant component such as surface tension-lowering activity and innate host defense.

Expression and characterization of Rab38, a new member of the Rab small G protein family

Rab38 is a new member of the Rab small G protein family that regulates intracellular vesicle trafficking. Rab38 is expressed in melanocytes and it has been clarified that a point mutation in the postulated GTP-binding domain of Rab38 is the gene responsible for oculocutaneous albinism in chocolate mice. However, basic information regarding recombinant protein production, intracellular location, and tissue-specific expression pattern has not yet been reported. We produced recombinant Rab38 using a baculovirus/insect cell-protein expression system. A combination of Triton X-114 phase separation and nickel-affinity chromatography yielded exclusively prenylated Rab38 that bound [alpha-32P]-GTP. The mRNA and the native protein were expressed in a tissue-specific manner, e.g., in the lung, skin, stomach, liver, and kidney. Freshly isolated rat alveolar type II cells were highly positive for the mRNA signal, but the signal was rapidly lost over time. Immunofluorescence staining demonstrated that expressed GST-tagged Rab38 was mainly co-localized with endoplasmic reticulum-resident protein and also partly with intermittent vesicles between the endoplasmic reticulum and the Golgi complex. These results indicate that Rab38 is expressed non-ubiquitously in specific tissues and regulates early vesicle transport relating to the endoplasmic reticulum, and hence suggest that Rab38 abnormality may cause multiple organ diseases as well as oculocutaneous albinism.

[A case of atypical pulmonary carcinoid accompanying skin metastasis]

A 73-year-old woman underwent cranial surgery in 1999 after receiving a diagnosis of suspected malignant meningioma. She began complaining of headache 2 years postoperatively, and around the same time, she noticed a painful skin tumor. She was then transferred to our hospital for further evaluation. The skin tumor was diagnosed by skin biopsy as an atypical metastatic carcinoid tumor. Systemic examination demonstrated a primary lesion in the left lung. Pulmonary, skin and bone biopsy samples exhibited the same pathological findings as those of the atypical pulmonary carcinoid tumor. She did not show any carcinoid symptoms. EP therapy (etoposide + carboplatin) and CAV therapy (cyclophosphamide + doxorubicin + vincristin) were administered, but there was no clinical response. The patient is currently doing well without chemotherapy and is being followed by the Outpatient Department.

[Implication of oxidant stress in airway inflammation]

There are many species of oxygen radicals in the environment. Inflammatory cells also produce many oxidants in biological tissues. The lung is constantly exposed to highest content of oxygen in the body, and frequently exposed to tobacco smoke, industrially polluted air, and exhausted gas. These conditions make the airway to be exposed to oxygen radicals, and may lead to subsequent oxidant stress and tissue injury, when the stress overwhelms the antioxidant system. Oxidants may also regulate expression of several proinflammatory cytokines with interacting with transcription factors. There is increasing evidence that COPD is related to airway oxidant stress. Measurement of some exhaled gas contents may be useful to monitor ongoing inflammation/oxidant stress and subsequent lipid peroxidation in COPD.

[An intra-pulmonary lymphnode resembling typical pulmonary primary adenocarcinoma on high-resolution computed tomographic (HR-CT) chest images]

A 40-year-old man was admitted to our hospital for further evaluation of a pulmonary nodule in chest radiographs. The 8-mm nodular lesion was located in the right anterior basal lobe on a plain chest radiograph, and showed 1) spiculation, 2) pleural indentation and 3) a converging vessel formation in high-resolution computed tomography of the chest. The radiographic findings were highly suggestive of primary pulmonary adenocarcinoma and the patient underwent video-assisted thoracoscopic surgery (VATS) to obtain a precise diagnosis. The nodule was diagnosed histopathologically as an intrapulmonary lymph node. In cases with such radiographic findings, careful attention should be paid in the differential diagnosis to distinguish intrapulmonary lymph nodes from primary pulmonary adenocarcinoma.

Time-dependent effect of pneumonectomy on alveolar epithelial fluid clearance in rat lungs

OBJECTIVE

Because pneumonectomy initiates compensatory growth of the remaining lung, we determined the time-dependent effects of pneumonectomy on alveolar fluid clearance capacity.

METHODS

Alveolar fluid clearance capacity with the Evans blue-labeled albumin concentration was measured in rats 3 hours, 2 days, 7 days, 14 days, and 28 days after left pneumonectomy. The mechanisms responsible for the increase in alveolar fluid clearance were explored.

RESULTS

Alveolar fluid clearance in the remaining lung was normal through 7 days and then increased 14 and 28 days after pneumonectomy. The increase in alveolar fluid clearance at 28 days after pneumonectomy was accounted primarily by an increase in amiloride-sensitive transport. The expression of epithelial sodium channel messenger RNA was increased in the remaining lung and in type II alveolar epithelial cells isolated from rats 28 days after pneumonectomy. The number of isolated type II cells was larger in pneumonectomized rats than in control rats. Also, beta-adrenergic agonist therapy increased the rate of alveolar fluid clearance at the 3-hour and 28-day time points.

CONCLUSIONS

The capacity to remove alveolar fluid in the remaining lung is maintained at a normal level for up to 7 days after pneumonectomy in a rat, and then there is a marked increase in amiloride-sensitive alveolar fluid transport capacity that might depend, at least in part, on increased expression of epithelial sodium channels in type II cells and in part on the increased number of type II cells.

[Function of lung surfactant and its deterioration]

Lung surfactant(LS) is a mixture of several lipids and four apolipoproteins(SP-A, -B, -C and -D) and lowers surface tension at air-liquid interface of alveoli. Most of LS is synthesized and secreted by alveolar type II cells. Although lamellar bodies are storage granules of LS, each component appears to take independent intracellular routes to reside in the granules. Patients with infantile respiratory distress syndrome(IRDS) or acute respiratory distress syndrome(ARDS) develop fatal respiratory failure due to lack of LS. In addition, acute phase of interstitial pneumonia also shows deterioration of LS and increased alveolar surface force resulting in decreased lung compliance. SP-A and SP-D are used as serum marker to evaluated activity of interstitial lung diseases. Recently, growing evidences are accumulating that LS plays a role in innate host defense in the lung against large species of bacteria, mycoplasma, and viruses.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Cell Movements during Gastrulation of Starfish Larvae

Archenteron formation was monitored by measurement of cellular volume, injection of tracer enzyme, and vital staining. The cellular volume of the whole embryo did not change significantly from the start of gastrulation to the beginning of the mesenchyme-migration stage; the archenteron increased from about 10-20% during these stages. Tracer injection revealed that the boundary between the progenies of the veg1 and veg2 blastomeres of 32-cell-stage embryos was in the outer layer at the early gastrula stage, and at the rear end of the stomach at the bipinnaria stage. These results demonstrate a migration of cells from the outer layer to the archenteron wall during starfish gastrulation. Vital staining marks around the blastopore showed that the presumptive esophagus, stomach, and intestine area were added to the archenteron at the start of gastrulation, during the early to late gastrula stage, and thereafter, respectively. Tracer injection also indicated that the presumptive zone of the cardiac sphincter was twisted about 180{deg} clockwise around the axis of the archenteron after the late gastrula stage, dragging the cells in the presumptive zone of the esophagus and stomach.

Chemical conversion of corticosteroids to 3 alpha,5 alpha-tetrahydro derivatives. Synthesis of 5 alpha-cortol 3-glucuronides and 5 alpha-cortolone 3-glucuronides

The synthesis of the 3-glucuronides of 5 alpha-cortol-20 alpha, 5 alpha-cortolone-20 alpha and their 20 beta-epimers is described. The 5 alpha-cortol 20,21-diacetates (12, 17) and 5 alpha-cortolone 20,21-diacetates (14, 19) were the key intermediates. Sodium borohydride reduction of the carbonyl group at C-20 in 5 alpha-tetrahydrocortisol 3-tert-butyldimethylsilyl ether 17,21-acetonide (8) gave the 20 alpha-hydroxy-acetonide (9). Selective removal of the acetonide ring was successful when the 20 alpha-acetoxy-17 alpha,21-acetonide (10) was treated with 50% acetic acid. Subsequent acetylation with acetic anhydride in pyridine, followed by removal of the protecting group at C-3 in the silyl ether-acetate (11) gave the desired 20 alpha-intermediate (12). The 11-ketone (14) was prepared from 11 by oxidation with pyridinium chlorochromate, followed by desilylation. The 20 beta-acetates (17, 19) were synthesized from 21-acetoxy-3 alpha,11 beta,17 alpha-trihydroxy-5 alpha-pregnan-20-one 3-tert-butyldimethylsilyl ether (15). Introduction of the glucuronyl residue at C-3 was carried out by means of the Koenigs-Knorr reaction.

[Autologous blood transfusion aided with erythropoietin in transurethral resection of the prostate]

Erythropoietin (EPO) with an established clinical efficacy in renal anemia has in recent years become applied as an aid to autologous blood transfusion in surgical patients. This report describes our experience with autotransfusion along with the use of EPO in transurethral resection of the prostate (TUR-P), indicating its usefulness. Ten patients with benign prostatic hypertrophy aged 60 to 74 years received 3000 units of EPO, with an iron preparation, nine times beginning 3 weeks prior to operation. Autologous blood of 300 ml was collected from the patient each at 2 and 1 week before operation and was used at TUR-P. Five other patients who underwent TUR-P with the same volume of autotransfusion accompanied by preparative medication with the iron alone served as controls. In the EPO treated group (mean age, 68.3 years) the mean value for hemoglobin concentration (Hb) was 14.0 +/- 1.6 g/dl on the day of operation, which showed a recovery rate of 94.9 +/- 5.4% (Hb recovery rate) as against the pre-EPO treatment value (mean: 14.8 +/- 1.3 g/dl). This Hb recovery rate was significantly greater (p less than 0.001) when compared to 82.2 +/- 2.5% in the control group (mean age, 68.2 years). Of the EPO treated patients, those in their sixties (n = 6; mean age, 66.3 years) exhibited a significantly higher Hb recovery rate (98.3 +/- 3.5%) than the rate (89.9 +/- 3.0%) for patients in their seventies (N = 4; mean age, 71.3 years) (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

[Clinical studies of bacteriuria in renal transplantation recipients. Correlation with pyuria and symptomatic genitourinary tract infection]

The clinical state of bacteriuria and its correlation with pyuria and symptomatic genitourinary tract infection (GUTI) were studied in 42 renal transplantation recipients who were followed up in the Kidney Center of Tokyo Women's Medical College over 6 months and who showed bacteriuria more than 3 times between January and December in 1987. The results were as follows. 1) Of the 42 recipients, bacteriuria was found less than 5 times in 19 patients, 6 to 10 times in 18 patients and more than 11 times in 5 patients. There was a tendency for the same bacteria to be isolated several times from the same patient. The most commonly isolated bacterias were Enterobacter, Enterococcus, Serratia and E. coli. 2) Bacteriuria was accompanied by pyuria in 33 patients (79%) and by symptomatic GUTI in 12 patients (29%). Bacteriuria without pyuria was shown in 9 patients (21%) without symptomatic GUTI and it was suggested that bacteriuria did not result in graft hypofunction after two years. 3) Of 16 patients with bacteriuria accompanied by pyuria, symptomatic GUTI occurred in 9 patients (56%). Of these, one patient was found to have VUR of the transplanted kidney, another was found to have VUR of the native kidney, and a third patient died due to interstitial pneumonitis presumably as a result of overimmunosuppression. Transplantation recipients with bacteriuria accompanied by pyuria develop symptomatic GUTIs frequently and should be treated with proper antibacterial agents. When bacteriuria continues, further examination should be performed for an organic disease of the urinary tract or an overimmunosuppressed state. When a patient shows bacteriuria without pyuria, chemotherapy is not needed and it is sufficient to observe the course carefully.

Changes of lung surfactant and pressure-volume curve in bleomycin-induced pulmonary fibrosis

We investigated whether alveolar surface force increased and participated in the lung pressure-volume relationship in bleomycin-induced pulmonary fibrosis in hamsters and, if so, whether lung surfactant was hampered in the lungs. On the air-filled pressure-volume curve, decreases of lung volume from control level were significantly higher at 3-8 cmH2O pressure on day 10 than on day 30. Because the change of lung tissue elasticity evaluated from the saline-filled pressure-volume curve was equal for the 2 days, the higher decrease of air volume on day 10 was due primarily to contribution of alveolar surface force. Pressure differences between deflation limbs of air-filled and saline-filled pressure-volume curves, which represented net alveolar surface force, were significantly higher at any lung volume between 50 and 90% total lung capacity on day 10, but almost no significance was observed on day 30. Phospholipid concentration in bronchoalveolar lavage fluid significantly decreased on day 10 but had improved by day 30. Analysis of phospholipid species in purified lung surfactant showed decreased fractions of disaturated phosphatidylcholine and phosphatidylglycerol on day 10. Surface-active properties of the surfactant, measured by a modified Wilhelmy balance, were remarkably hampered on day 10, but most of them had improved by day 30. We consider that the quantitative and functional abnormalities of lung surfactant have a part in the aggravation of lung mechanics in the acute phase of pulmonary fibrosis.

Chromosomal behavior in starfish (Asterina pectinifera) zygotes under the effect of aphidicolin, an inhibitor of DNA polymerase

When calf thymus histones were labeled fluorescently and microinjected into oocytes of the starfish, Asterina pectinifera, the labeled histones visualized chromosomes during maturation division and cleavage. In doing so, we confirmed the previously reported phenomenon that chromosomes became incompetent at the first cleavage in the aphidicolin-treated egg, although cleavage itself took place. Moreover, we found that chromosomes were aligned at the equator of the metaphase spindle of the first cleavage and that they did not separate into two groups at all, but made a lump in the middle of the spindle. Chromosomes finally entered one blastomere, although they did not participate in the following karyokinesis. DNA and microtubules were examined by cytochemistry and immunofluorescence in order to investigate the relation between chromosome movement and the microtubular cytoskeleton. The mitotic apparatus developed and grew in the aphidicolin-treated cells in the same manner as those in normal cells without normal chromatin condensation or chromosome movement during the first cleavage. However, the mitotic apparatus consisted of two asters without the spindle formed at subsequent cleavages. Electron microscopic study revealed that chromosomes did not condense normally and kinetochores were not detected during the first cleavage. These results indicate that the dynamic changes in microtubular structures during mitosis have poor relation with the chromosome behavior such as prophase chromosome condensation and anaphase chromosome movement.

Chemical conversion of corticosteroids to 3 alpha,5 alpha-tetrahydro derivatives. Synthesis of allotetrahydrocortisol glucuronides and allotetrahydrocortisone glucuronides

The synthesis of the 3- and 21-glucuronides of allotetrahydrocortisol (allo-THF) and allotetrahydrocortisone (allo-THE) is described. 5 alpha-Dihydrocortisol (5) was prepared by selective hydrogenation of 21-acetoxy-3, 11 beta, 17 alpha-trihydroxy-3,5-pregnadien-20-one 3-ethyl ether (3), followed by acid hydrolysis and saponification. When 5 alpha-dihydrocortisol 21-tetrahydropyranyl ether (6) was treated with potassium tri-sec-butylborohydride in tetrahydrofuran under mild conditions, regioselective and stereoselective reduction at C-3 took place to give allo-THF 21-tetrahydropyranyl either (7). This compound was converted into the 3- and 21-monoacetates of allo-THF and allo-THE, key intermediates. Introduction of the glucuronyl residue at C-3 or C-21 was carried out by means of the Koenigs-Knorr reaction. Prior to saponification yielding the 3-glucuronides (20,23), the alkali-sensitive ketol side chain at C-17 was protected as 20-semicarbazones.

[Effects of vitamin E deficiency on bleomycin-induced pulmonary fibrosis in hamsters]

We examined the effect of free radicals on lung defense mechanism in bleomycin (BLM)-induced pulmonary fibrosis in hamsters. The concentration of vitamin E (VE) in the lung tissue increased significantly after intratracheal BLM administration. VE deficient hamsters showed increased lipid peroxide values in the lung tissue at a very early stage after BLM treatment. This was followed by decreased superoxide dismutase activities in the lung tissue. The results indicate that; 1) VE appears to be necessary for the prevention of lipid peroxidation in BLM-induced oxidant lung injury, 2) VE deficiency produces a large number of free radicals at the early stage after BLM treatment, and might induce protease-antiprotease imbalance within the lung, which probably causes an emphysematous change in the BLM-treated lung at a late stage after BLM administration.