ABCA3 is a lamellar body membrane protein in human lung alveolar type II cells.

The ABCA3 gene, of the ABCA subclass of ATP-binding cassette (ABC) transporters, is expressed exclusively in lung. We report here the cloning, molecular characterization, and distribution of human ABCA3 in the lung. Immunoblot analysis using the specific antibody reveals a 150-kDa protein in the crude membrane fraction of human lung. Immunohistochemical analyses of alveoli show that ABCA3 is expressed only in the type II cells expressing surfactant protein A. At the ultrastructural level, ABCA3 immunoreactivity was detected mostly at the limiting membrane of the lamellar bodies. Since members of the ABCA transporter family are known to be involved in transmembrane transport of endogenous lipids, our findings suggest that ABCA3 plays an important role in the formation of pulmonary surfactant in type II cells.

Histologic and ultrastructural features of normal human parietal pericardium.

Morphologic studies of normal anterior parietal pericardium from seven patients revealed this tissue to be composed of three layers: (1) the serosa, consisting of a surface layer of mesothelial cells and a narrow submesothelial space, (2) the fibrosa, containing variously oriented layers of collagen fibrils and small elastic fibers, and (3) the epipericardial connective tissue layer, containing mainly large coarse bundles of collagen and forming part of the pericardiosternal ligament. Scanning electron microscopic examination is most useful for study of the surface features of pericardial mesothelial cells, which have single cilia and are covered with microvilli. The latter bear friction and increase the surface area for fluid transport. Junctional complexes between adjacent mesothelial cells consist of desmosomes, which reinforce intercellular adhesion and zonulae occludentes, which form permeability barriers. Actin-like filaments (50 A in diameter) are present in microvilli and in immediately subjacent regions of the cells; these filaments mediate changes in cell shape. Intermediate filaments (100 A in diameter) are associated with desmosomes and form bundles in the perinuclear regions; these filaments provide structural support to the cytoplasm.

Aerogenous spread of primary lung adenocarcinoma induces ultrastructural remodeling of the alveolar capillary endothelium.

To determine whether pulmonary alveolar capillaries manifest ultrastructural remodeling at areas of neoplastic invasion of primary lung adenocarcinomas, we examined 17 well-differentiated adenocarcinomas of lung (2 bronchioloalveolar and 15 papillary adenocarcinomas) by electron microscopy. The expression of vascular endothelial growth factor (VEGF) and proliferating cell nuclear antigen (PCNA) was demonstrated by immunohistochemical stainings. VEGF messenger RNA (mRNA) isoforms were detected by reverse-transcription polymerase chain reaction (RT-PCR) in alveolar walls microdissected from normal and tumor-associated tissues. Cytoplasm of neoplastic cells expressed VEGF protein in all patients. Endothelial cell nuclei of alveolar capillaries showed positive reaction for PCNA. Alveolar capillary lumina were distended like venules, and some intercellular junctions remained open. The cytoplasm of the capillary endothelial cells was enlarged and developed numerous organelles such as Weibel-Palade bodies and vesiculovacuolar organelles, in contrast to marked attenuation in their normal counterpart. Capillary sprouting occurred from proper alveolar capillaries in 2 patients. Cytoplasmic segments became extremely attenuated and developed diaphragm-like fenestrae in 65% of the patients. A relatively higher expression of diffusable isoforms of VEGF mRNA was seen in the tumor-bearing alveolar walls than in normal walls. Expression of KDR (one of the VEGF receptors) mRNA in tumor exceeded that in normal tissues. These results suggest that diffusable isoforms of VEGF mRNA released from the neoplastic cells are deeply involved in the induction of growth activity of alveolar capillary endothelial cells as much as in the characterization of tumor-associated microvessels in primary lung adenocarcinomas.

A new bronchofiberscope for the study of diseases of very peripheral airways.

A new device, the BF-1.8T, has been designed to go through the 2.6 mm channel of the conventional fiberoptic bronchoscope (Olympus BF type ITR). It measures 1.8 mm in outer diameter; it has a visual angle of 75 degrees, a range of observation of 3 to 30 mm, an effective length of 950 mm, and a total length of 1120 mm. The tip can extend from the wedge of the outside endoscope by up to 180 mm, providing safe manipulation by the examiner. The results of four cases were briefly presented out of nearly 100 so far examined in our hospital. Selective alveolobronchography (SAB) was simultaneously performed because SAB could be done easily and the results were complementary to the direct observation which was obtained with the BF-1.8T. These data were also correlated with the results of transbronchial lung biopsies.

Endoscopic observation of peripheral airway lesions.

Peripheral airways of 2 mm or less in diameter were observed in 142 patients by means of an ultrathin bronchofiberscope measuring 1.8 mm in outside diameter. On the basis of the observed and photographed endoscopic findings, an endoscopic classification of peripheral airway lesions was proposed. The endoscopic findings showed changes in the bronchial wall consisting of reddening, pallor, absence of mucosal luster, edema, engorgement of blood vessels, irregular mucosal surface, and elevated mucosa. In the lumen, stenosis, obstruction, ectasis, and deformation due to pressure were recognized, in addition to excessive secretion and pigmentation as morphologic abnormalities or abnormal findings at bifurcation.

Papilloma of renal pelvis in childhood.

A papilloma in the renal pelvis of a five-year-old girl is reported. The transitional cell tumors of the renal pelvis in the pediatric age group are reviewed, and this is found to be the first case of a benign papilloma in childhood. We believe this pathologic entity should be included in the differential diagnosis of hematuria in a child.

Histological characteristics of the healing process of frozen skin allograft used in the treatment of burns.

Combined transplantation of skin autograft and allograft was used for the treatment of severe burns. The allografts were obtained from cadavers and were pretreated with 15 per cent glycerol for 2 h at 4 degrees C then frozen at -80 degrees C until used. Patches of autografts were placed over the burns and were covered by a stretched mesh of allografts. Biopsy samples of transplanted skin were obtained from 5 days to 4 weeks after grafting. Sections were examined by histological and immunohistochemical strainings. At 4 days, the epidermal-dermal junction of allografted skin was separated due to migration of epithelial cells derived from autograft epidermis or from skin appendages of recipient dermis. At 2 weeks, dermal fibroblasts and capillaries proliferated in autografts. At 3 weeks, the dermal components of the allograft were covered by epithelial cells from recipient tissue and were invaded by fibroblasts and capillaries. At 4 weeks, allografted skin was replaced by granulation tissue, which mediated the adhesion of the grafts to the underlying tissue. Skin allografts with a freeze-thawing pretreatment provide an appropriate matrix for the epithelial relining and for the growth of granulation tissue in burned skin.

Multiple brain abscesses complicating treatment of a severe burn injury: an unusual case report.

Death after burn injury is usually due to complications, of which bacterial causes are dominant. We treated a patient with a burn injury who had the unusual complication of multiple brain abscesses, which were caused by methicillin-resistant Staphylococcus aureus (MRSA). The patient, a 27-year-old man, had MRSA septicemia on day 9 and pneumonia on day 18. Hemiparesis, which was the first manifestation of brain abscesses, occurred on day 27. Although antibiotics were administered aggressively, the infection was never resolved, and the patient died on day 50. Brain abscesses and MRSA infection are still major problems in the treatment of burns. This is the first report of (metastatic) multiple brain abscesses complicating treatment of a burn injury.

Heterogeneous distribution of thrombomodulin and von Willebrand factor in endothelial cells in the human pulmonary microvessels.

Laser scanning confocal fluorescence microscopy techniques were used to study the localization of von Willebrand factor (vWf; Factor VIII-related antigen) and thrombomodulin (transmembrane receptor for thrombin) in the microvascular endothelial cells in the normal human lung. Tissues were obtained from lobectomy specimens resected for solitary nodules (7 adenocarcinomas and 4 hamartomas) from 11 patients. The plasma membranes of the capillary endothelial cells in the alveolar zones (A-zones) showed red linear fluorescence for thrombomodulin. However, their cytoplasm was mostly unreactive for vWf. The microvessels which were located in the connective tissue (C-zones), including peribronchial, and subpleural areas and large vascular walls, consistently demonstrated band-like green fluorescence for vWf in their cytoplasm, and their plasma membranes usually lacked reactivity for thrombomodulin. Only a limited number of peribronchial capillaries measuring <10 microm in diameter showed a mosaic-like appearance, in which red fluorescence along the plasma membranes was found together with green fluorescence in the subjacent cytoplasm. In the juxtaalveolar (J-zones) microvessels located along the borders between A- and C-zones, and measuring up to 40 microm in diameter, the endothelial cells showed a mosaic-like pattern of distribution of the two antigens. However, the localization of thrombomodulin in the J-zone microvessels was separate and independent from that of vWf. The thrombomodulin-reactive cells were directly connected to the alveolar capillary endothelial cells. Heterogeneous patterns of distribution of thrombomodulin and vWf suggest that topographic differences of endothelial function occur to maintain a balance of coagulation and anticoagulation in the normal human lung.

[Human fetal mast cells under development of the skin and airways].

We made histochemical and ultrastructural studies of mast cells of the skin and airways in human fetuses (7 to 40 weeks' gestation) and newborn infants. Epithelial differentiation of the skin and bronchial airways was assessed of immunohistochemical characteristics, especially on their basal cells. Histological phenotype and the characteristics to anti-total keratin antibody became identical with the phenotype in the adult by the 11th and 36th week of gestation, respectively. Interstitial fibroblastoid cells appeared oval in shape and remained relatively immature to the termination. Mast cells were first recognized by electron microscopy in the fetal skin of 18-week-old fetuses and histochemically detected in both skin and airways of 24-week-old fetuses. Mast cell counts under high power magnification (40X optical lens) light microscopy gradually increased and made a relatively dramatic rise in the early postnatal periods. The cytoplasm of mast cells showed irregular pseudopod-like elongations which gradually developed microvillous protrusions. It contained immature granules composed of varieties of morphology such as amorphous dense bodies, vesicles with dense cores, particulates and their compound forms. They were located in a corner of the cytoplasm surrounded by lamellated rough-surfaced endoplasmic reticulum. These granules became scattered widely in the cytoplasm showing distinct particulate type. Granules typical of the scroll type became dominant in the process of maturation, and the transformation of crystal-substructures occasionally took place. Prior to birth, mast cell granules fully developed as mature as those in the adult. This process of granule maturation is indicative of a reversed proceeding of slow degranulation, which is commonly seen in the so-called mucosal mast cells.

[Adhesion ultrastructures of mononuclear cells in experimentally-induced silicotic granuloma].

Experimental silicosis was induced by intratracheal infusions of 1 ml saline containing 50 mg standard silica (less than 5 microns diameter) in Sprague-Dawley rats. The lung tissues were observed histologically and ultrastructurally from half an hour up to 4 months. Macrophages, neutrophils, desquamated cells and their debris piled up around the alveolar ducts where the central cores of silicotic granuloma appeared. The granuloma became apparent by day 4 after the infusion and were covered by type II alveolar epithelial cells and bronchiolar cuboidal epithelial cells. Macrophages, fibroblasts and epithelial cells began to react to the antibody against proliferating cell nuclear antigen (PCNA) indicating self-replication on day 1. Macrophages in the granuloma made a close interdigitation with adjacent macrophages, and they gradually formed subplasmalemmal linear densities (SPLD) as paired forms between adjacent plasma membranes, and unpaired forms facing the interstitial matrix. SPLD were composed of linear densities with actin-like microfilaments along the leaflets of plasma membrane and were associated with extracellular dense bands which resembled a limited length of basement membrane. Interdigitation and SPLD structures were quite rare on day 1, but the number of macrophages with both structures increasingly appeared. The frequency of SPLD in macrophages also increased on a time course of granuloma maturation up to 4 months. Thus SPLD, which were originally found in the mononuclear phagocytes including macrophages, epithelioid cells and multi-nucleated giant cells, particularly in immune granuloma of man, also played a basic role in immobilizing macrophages in lesions of silica-induced granulomas.

[Endotoxin-induced lung injury--the role of leukocytes and oxidants].

Endotoxin shock was made in guinea pigs to understand the initial pathogenesis in connection with the oxygen radicals from leukocytes. The intraperitoneal injection of LD50 E. coli endotoxin induced rapid leukopenia, and leukocytosis appeared at 24 hours of injection. The cell differential counts of bronchoalveolar lavage fluid revealed a significant increase in eosinophil at 10 and 30 minutes. There was also a significant increase in neutrophil at 24 hours. The activity of superoxide dismutase in the lung tissue decreased at 10 minutes of injection and remained low for 24 hours. Malonaldehyde, a lipid peroxidation metabolite by oxidants, gradually increased and reached a maximal value at 60 minutes of injection. The lung damage was histologically characterized by a rapid appearance of the alveolar edema and scattered infiltration of granulocytes. These suggested the endotoxin injection induced activation of granulocytes recruited from peripheral blood to cause oxidant reaction in lung tissues, which finally produced acute lung injury.