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The study aimed to clarify the antitumor effects of radiotherapy, chemotherapy, hyperthermia, and combinations thereof in an effort to devise a highly effective noninvasive regimen. The human KB cell line, derived from an epidermal carcinoma of the mouth, was used for the experiments. The antitumor effects of monotherapy—with radiotherapy of 6-MV X-rays, 43°C hyperthermia, and chemotherapy with the taxoid antineoplastic drug docetaxel—as well as combinations of these therapies were evaluated using a colony assay. Compared with monotherapy of 6-MV X-rays, 43°C heat, and docetaxel, radiation combined with 43°C heat showed a slight increase in sensitization; radiation or 43°C heat combined with docetaxel showed stronger sensitization. Furthermore, more pronounced sensitization was observed with a three-way combination of radiation, 43°C heat, and docetaxel. These results suggest that the combined use of radiation, 43°C heat, and docetaxel will improve the therapeutic efficacy against malignant tumors by increasing sensitization to the antitumor effects of each therapy. The results also suggest that it is possible to reduce the dosage of the individual therapies in combination therapy.

We describe a case of huge solitary neurofibroma in the oral cavity. A 59-year-old man with a history of dysphagia presented with swelling of the tongue. Magnetic resonance (MR) images showed a lesion extending from the base of the tongue to the floor of the mouth located above the mylohyoid muscle. The dimensions of the enucleated tumor were 95 mm in length, 65 mm in width, and 15 mm in thickness. Histopathological examination revealed that the lesion was a diffuse neurofibroma.

Sialolipoma is a new variant of salivary gland lipoma, which was first described in 2001. We report a rare case of sialolipoma of the palate, and review another 10 cases affecting the minor salivary gland and 13 affecting the major salivary gland, together with details of the clinical and histopathological findings.

Papillary squamous cell carcinoma (PSCC) is a rare variant of squamous cell carcinoma (SCC) having an exophytic papillary component. We report the case of a 60-year-old woman with oral PSCC of the gingiva. Histopathologically, the operative specimen was composed of exophytic papillary and invasive proliferations of atypical squamous epithelium, from which a pathological diagnosis of PSCC was made. On the Ki-67 labeling index, the exophytic area of PSCC (42.8%) was higher than the superficial area of SCC (20.7%) and papilloma (38.9%). The invasive area of PSCC (53.1%) was slightly higher than that of SCC (52.2%). The PSCC had high proliferative activity in both the exophytic and invasive areas, which reflected the PSCC characteristic features of papillary and invasive growths. Clinicians should check for the existence of PSCC in the oromaxillofacial region and provide treatment as they do for SCC.

Epithelial-mesenchymal interactions play a crucial role in the induction of life-long cyclic transformations of hair follicles. Many studies have already demonstrated several candidates for the soluble factors secreted from the mesenchymal components of the hair follicle, i.e. the follicular papilla (FP) and connective tissue sheath (CTS), which may be responsible for hair cycling. In this paper, we focused on cell-cell contact between FP cells (FPCs), between CTS cells (CTSCs), and between FPCs and CTSCs that may allow these mesenchymal components to function as a syncytium during hair cycling. Electron microscopic examination of the FP and the CTS obtained from human scalp revealed a tri-lamellar structure of the plasma membranes, which is a characteristic of gap junctions at the cell-cell contacting area. The immunohistochemical study with anticonnexin 43 Ab using a confocal laser scanning microscope demonstrated numerous spotted positive signals scattered throughout the FP. In the CTS, spotted positive signals were arranged linearly along the basement membrane of the hair follicle. In particular, these positive spots were aggregated in the transitional region between the FP and the CTS. By Western blot analysis of total protein extracts from the cultured FPCs and neonatal human dermal fibroblasts using anticonnexin 43 antibody, a positive band corresponding to connexin 43 was detected at 43 kDa on both the FPC lane and fibroblast lane. These findings suggest that the FP and the CTS form a communicating network through gap junctions, which may play a role in controlling the dynamic structural changes of hair follicles during hair cycling.

Histidine decarboxylase (HDC) synthesizes histamine from histidine in mammals. To evaluate the role of histamine, we generated HDC-deficient mice using a gene targeting method. The mice showed a histamine deficiency and lacked histamine-synthesizing activity from histidine. These HDC-deficient mice are viable and fertile but exhibit a decrease in the numbers of mast cells while the remaining mast cells show an altered morphology and reduced granular content. The amounts of mast cell granular proteases were tremendously reduced. The HDC-deficient mice provide a unique and promising model for studying the role of histamine in a broad range of normal and disease processes.

Intraepidermal nerve fibers were studied by electron microscopy in chronically photodamaged preauricular skin and in paired sun-protected postauricular sites of 20 Caucasian women aged 56-70 years. As previously reported, basal keratinocytes in the sun-exposed skin showed various degrees of degenerative changes including intracellular vacuolar structures and widened intercellular spaces. Neurites were frequently closely apposed to basal keratinocytes in preauricular sun-exposed skin, but were observed less than 10% as often in sun-protected postauricular skin. When degree of epidermal photodamage was quantified by means of the number of degenerated keratinocytes per 100 keratinocytes in the basal layer, the number of intraepidermal nerve fibers was significantly correlated by linear regression analysis to the severity of epidermal photodamage (r = 0.913) independent of anatomical sites. These results demonstrate for the first time a correlation between degree of epidermal innervation and chronic photodamage and suggest the possibility of neural involvement in the pathophysiology and/or repair of photodamaged skin.

Communication between the nervous system and epidermal melanocytes has been suspected on the basis of their common embryologic origin and apparent parallel involvement in several disease processes, but never proven. In this study, confocal microscopic analysis of human skin sections stained with antibodies specific for melanocytes and nerve fibers showed intraepidermal nerve endings in contact with melanocytes. This intimate contact was confirmed by electron microscopy, which further demonstrated thickening of apposing plasma membranes between melanocytes and nerve fibers, similar to synaptic contacts seen in nervous tissue. Since many intraepidermal nerve fibers are afferent nerves that act in a "neurosecretory" fashion through their terminals, cultured human melanocytes were stimulated with calcitonin gene-related peptide (CGRP), substance P, or vasoactive intestinal peptide, neuropeptides known to be present in cutaneous nerves, to examine their possible functions in the epidermal melanin unit. CGRP increased DNA synthesis rate of melanocytes in a concentration- and time-dependent manner. Cell yields after 5 d were increased 25% compared with controls maintained in an otherwise optimized medium. Furthermore, stimulation by CGRP induced rapid and dose-dependent accumulation of intracellular cAMP, suggesting that the mitogenic effect is mediated by the cAMP pathway. These studies confirm and expand a single earlier report in an animal model of physical contact between melanocytes and cutaneous nerves and for the first time strongly suggest that the nervous system may exert a tonic effect on melanocytes in normal or diseased human skin.

Melanocytes synthesize melanin and transfer it to keratinocytes via dendritic processes. Keratinocytes are known to produce constitutively several factors, including endothelin-1 (ET-1), that together affect melanocyte proliferation, migration, melanogenesis, and dendrite formation. After ultraviolet (UV) irradiation, synthesis and secretion of ET-1 are up-regulated in keratinocytes. Because UV irradiation of skin is known to be associated with increased melanocyte dendricity, and because medium conditioned by UV-irrdiated keratinocytes (UV-KCM) induces melanocyte dendricity to a greater degree than does baseline keratinocyte-conditioned medium (KCM), we investigated whether ET-1 promotes melanocyte dendricity. ET-1, originally recognized as a vasoconstricitive peptide, has recently been shown to stimulate melanocyte proliferation and tyrosinase activity. We now report that ET-1 supplementation of cultured melanocytes significantly increases the percentage of dendritic melanocytes, as well as dendrite length, in a dose-dependent manner. Moreover, UV-KCM was found to contain over 25-fold more ET-1 than KCM, and ET-1 supplementation of KCM induced melanocyte dendricity comparable to that induced by UV-KCM. Further, melanocyte dendricity induced by UV-KCM was significantly inhibited by the addition of anti-ET-1 monoclonal antibody to the medium, suggesting that the UV-KCM effect on melanocyte dendricity is mediated largely through ET-1. Our findings suggested that in the skin, ET-1 of keratinocyte origin promotes melanocyte dendricity in response to UV irradiation.

We have established a dermal fibroblast-like stromal cell line, DFB-1, and a clone, 12E2, from epidermal sheets prepared from the skin of BALB/c mouse ears by trypsin digestion. They were suggested to be fibroblasts or myofibroblasts, as 1) they were polygonal or spindle-shaped under the phasecontrast microscope, 2) they did not possess any tonofilaments or desmosomes, and 3) they did not express any marker for bone marrow-derived cells or macrophages. Interestingly, these cells showed a unique phenomenon of "pseudoemperiporesis," which was first recognized in the interaction between thymic nurse cells and thymocytes. Namely, two T-cell clones and one T-cell hybridoma migrated beneath the cytoplasmic projections of the fibroblastlike cutaneous stromal cells in culture. Furthermore, secretion of interleukin 7 by these cells was confirmed by bioassay using an IL-7-dependent cell line and by inhibition with anti-interleukin 7 antibody, and the expression of interleukin 7 mRNA was also demonstrated in these cells by a combination of reverse-transcriptase polymerase chain reaction and Southern blot analysis. These data strongly suggest the presence of unique stromal cells even in the skin, probably at the upper dermis, which can function like the nurse cells in the thymus. These stromal cells may play a crucial role in cutaneous immunophysiology.

E- and P-cadherin are calcium (Ca2+)-dependent cell adhesion molecules important in the morphogenesis and maintenance of skin structure. By use of flow cytometry and specific antibodies, we now show that cultured human melanocytes express E- and P-cadherin on their surfaces, and that these molecules have the same characteristics as reported for other cell types. Specifically, melanocyte cadherins are sensitive to trypsin digestion in the absence of Ca2+ and are protected from trypsin degradation by Ca2+, and are functional at 37 degrees C but not at 4 degrees C. We further show that melanocytes contain mRNA transcripts encoding both E- and P-cadherin. Adhesion of cultured melanocytes to keratinocyte monolayers is abolished by pre-treatment of the melanocytes with trypsin/EDTA, which degrades E- and P-cadherins, is greatly reduced by anti-E-cadherin antibodies and is slightly reduced by antibodies to P-cadherin, alpha 2, alpha 3 and beta 1 integrins. In contrast to normal melanocytes, eight of nine melanoma cell lines lacked E-cadherin (or expressed markedly reduced levels) and five were negative for P-cadherin. Melanoma cells also failed to adhere to keratinocyte monolayers. These results demonstrate that normal human melanocytes express functional E- and P-cadherin and that E-cadherin is primarily responsible for adhesion of human melanocytes to keratinocytes in vitro. In addition, transformed melanocytes express markedly reduced levels of E- and P-cadherin, and exhibit decreased affinity for normal keratinocytes in vitro, suggesting that loss of cadherins may play a role in melanoma metastasis.

In an in vitro study to examine whether corneocytes stimulate neutrophils to cause a respiratory burst, we found that stratum corneum (SC) homogenates obtained from the sole of healthy individuals induced a substantial respiratory burst in human neutrophils when assessed by lucigenin-dependent chemiluminescence (CL) in the presence of the fresh human serum. Electron microscopically, the interaction between corneocytes and neutrophils was shown as distinctive deformation of the neutrophils adhering to the surface of the corneocytes that suggested a specific binding between SC and neutrophils. In contrast, in the heat-inactivated serum-supplemented system, the peak intensity of SC-induced CL was significantly decreased, being only slightly higher than that noted in the SC-free background. To circumvent the time-consuming preparation of the SC homogenates, we measured CL with a sheet of SC obtained by stripping with adhesive cellophane tape. In this case we used plasma because the complement was easily activated by cellophane tape itself when serum was used. To evaluate the influence of the location of horny tissue in the SC on CL in neutrophils, we used SC sheets stripped with cellophane tape from various levels of the SC. However, there was no significant difference in CL responses between SC sheets obtained by 1, 2, 3, 5, 10, or 15 strippings. Our findings suggest that when SC comes in contact with serum, it is opsonized by C3b, and such SC causes a respiratory burst of neutrophils following their specific binding on the surface of corneocytes.

In an in vitro study to examine whether corneocytes stimulate neutrophils to cause a respiratory burst, we found that stratum corneum (SC) homogenates obtained from the sole of healthy individuals induced a substantial respiratory burst in human neutrophils when assessed by lucigenin-dependent chemiluminescence (CL) in the presence of the nontreated fresh human serum (NTS) . Electronmicroscopically the interaction between corneocyte and neutrophils was shown as distinctive deformation of the neutrophils adhering to the surface of the corneo-cytes that suggested a specific binding between them. In contrast, in the heat-inactivated serum (HIS) -supplemented system the peak inensity of SC-induced CL was significantly decreased, being only slightly higher than that noted in the SC-free background. To circumvent the time-consuming preparation of the SC homogenates we measured CL with a sheet of SC obtained by stripping with adhesive cellophane tape. In this case we used plasma because complement in the serum was easily activated by cellophane tape itself. To evaluate the influence of the location of horny tissue in the SC on the induction of CL responses, we used SC sheets stripped with cellophane tape from various levels of the SC. Howeve, there was no significant difference in CL response between SC sheets obtained 1, 2, 3, 5, 10 or 15 strippings.Our findings suggest that, when the SC comes in contact with serum, it is opsonized by C 3 b and that such SC causes a respiratory burst of neutrophils following their physical contact. Extracellular release of the resultant active oxygen species probably causes damaging effects on the surrounding SC and epider_ mal tissue and such an interaction between SC and neutrophils seems to be involved in the formation of subcorneal sterile pustules noted in pustular dermatoses.

Short photoreceptor cells of the lamprey retina exhibited a 30% increase in the width of the myoid process and a 20% increase in that of the axonal process during a 12-h light period, compared to the measurements obtained during a 12-h dark period. An increase in the amount of cytoplasm, dilation of ER cisterns, and swelling of the nucleus appeared to cause the enlargement of the myoid parts. Accumulation of synaptic vesicles occurred concurrently with a thickening of the axonal process. These morphological changes presumably represent a phase of the diurnal cycle and current synaptic activity of the short cell. By contrast, the long photorecpetor cell showed neither measurable changes nor any indication of “retinomotor movement”.

A tumor-specific targeting system for cancer gene therapy was studied using the human telomerase reverse transcriptase (hTERT) promoter. Telomerase activity is increased in most tumors but not detected in most normal cells. We developed the recombinant adenovirus, carrying human herpes simplex virus thymidine kinase gene under the control of the hTERT promoter (AdhTERTtk) to obtain restricted expression of a suicide gene only in tumor cells. We found that transcriptional activity of hTERT was 2- to 9-fold higher in undifferentiated thyroid carcinoma cell lines than that of the Simian virus 40 promoter in transient transfection assay. Undifferentiated thyroid carcinoma cell lines were infected with AdhTERTtk, and sensitivity to ganciclovir (GCV) was analyzed. Cell viability was decreased in a GCV dose-dependent manner after treatment with AdhTERTtk/GCV. The cell-killing ability of AdhTERTtk in all thyroid or nonthyroid carcinoma cell lines tested was similar to AdCMVtk, which carries herpes simplex virus thymidine kinase gene driven by the cytomegalovirus promoter. However, normal cell lines were largely unaffected by AdhTERTtk/GCV, whereas these cells were also sensitive to GCV after infection with AdCMVtk. A xenograft model was established by transplanting human differentiated or undifferentiated thyroid carcinoma cells into Balb-C nude mice. The injections of AdhTERTtk into tumors and ip administration of GCV showed significant inhibition of tumor growth, similar to AdCMVtk/GCV treatment. Systemic administrations of adenovirus and GCV to normal rats demonstrated remarkable increase of serum liver transaminase levels and severe hepatic damages in pathological examinations in AdCMVtk-injected rats but not in the AdhTERTtk group. These results indicate that the AdhTERTtk/GCV system is a promising therapy for undifferentiated thyroid carcinoma, which is one of the most malignant tumors, without damage to normal tissues.

A 45-year-old male was admitted because of chest pain, lumbago, and bilateral ankle pain. Examination disclosed hypophosphatemic osteomalacia, acquired Fanconi syndrome, and abnormalities in distal nephron such as distal renal tubular acidosis and renal diabetes insipidus. Further exploration revealed IgA kappa multiple myeloma excreting urinary Bence Jones protein (kappa-light chain). Renal biopsy revealed thick basement membranes and elec-tron-dense crystals in proximal tubular epithelial cells. Immunofluorescent studies revealed deposition of kappa-light chain in renal tubular epithelial cells that caused the renal tubular damage. Although the osteomalacia was relieved by medical treatment, the urinary Bence Jones protein and the renal tubular defects were not improved by the chemotherapy for the myeloma. The patient died of exacerbation of multiple myeloma at 50 years of age.

Although the programmed cell death mediated by thyroid hormone is not well evaluated in mammalian cells, thyroid hormone plays a crucial role in differentiation of the cells during the metamorphosis of Xenopus, suggesting that thyroid hormone has the potential ability to induce the apoptosis. To investigate the thyroid hormone-inducible apoptosis, we cultured HL-60 cells with various amounts of all-trans-retinoic acid (RA) and l-T3. T3 alone did not induce the apoptosis of the cells. T3, however, suppressed the proliferation of cells in the presence of RA. DNA ladder and microscopical examination showed that the reduction of cell number was due to the apoptosis induced by RA. These findings suggested that T3 affects the apoptotic process during the differentiation of HL-60 cells by RA. T3-inducible apoptosis may require the factors augmented by RA in HL-60 cells.

We report a 19-year-old female case of acromegaly associated with Chiari-I malformation and polycystic ovary syndrome. She also had syringomyelia and thoracic scoliosis. Although the association of acromegaly and Chiari-I malformation was by chance, exaggerated secretion of growth hormone may have aggravated the scoliosis. The incidence of polycystic ovary in acromegalic patients remains to be elucidated. However, elevation of plasma insulin and insulin-like growth factor, that is usually observed in patients with acromegaly, could stimulate androgen production in the ovaries. The patient was successfully treated with transsphenoidal adenomectomy for pituitary tumor and correction surgery for thoracic scoliosis.

We report a case of acrokeratosis paraneoplastica (AP; Bazex syndrome), characterized by typical palmoplantar hyperkeratosis and psoriasiform scaly erythema of the acral regions, associated with primary cutaneous squamous cell carcinoma (SCC) on the left lower leg. This 54-year-old Japanese man subsequently developed vitiligo, and alopecia areata of the scalp. Serial monitoring of squamous cell carcinoma antigen (SCC-Ag) demonstrated that the severity of the clinical manifestations of AP paralleled the serum concentrations of SCC-Ag. We suggest that an immune-mediated mechanism underlies the development of AP in this patient.

We examined epidermal impairment in photodamaged Caucasian skin by light and electron microscopy and observed two types of degeneration of the basal and suprabasal keratinocytes. The first was an electron-lucent degeneration predominantly seen in the periphery of the cells. The marked lucent degeneration occurred in 14% of the basal and suprabasal keratinocytes, predominantly in cells immediately adjacent to melanocytes. In skin specimens with a large number of such damaged keratinocytes, bleb-like keratinocytic protrusions or electron-lucent intercellular structures were also seen. Many vacuolar structures were observed just under the dermoepidermal junction, occupying 9% of the junction length. These structures were produced by herniation of the degenerative portion of the basal and suprabasal keratinocytes, and appeared to be phagocytized by dermal macrophages. The vacuolar alterations in the basal layer and dermoepidermal junction previously reported at the light microscopic level probably represent these intercellular lucent structures, bleb-like protrusions and vacuole-like structures at the electron microscopic level. The second type, dark-staining keratinocytes, probably representing an extensive degenerative process, constituted 4% of the basal and suprabasal keratinocytes. After 12 months of topical tretinoin treatment, dramatic improvement of both degenerative processes of the keratinocytes was noted.

Formation of subcorneal pustules characterizes skin lesions infected by Staphylococcus aureus. To elucidate the mechanism underlying the subcorneal pustule formation as well as that of anti-bacterial host defence, we studied the effect of staphylococcal protein A on the interaction between the stratum corneum (SC) and neutrophils. We found that protein A significantly promoted opsonized SC-induced chemiluminescence (CL) in neutrophils. This was specific to SC because no enhancement was observed with opsonized zymosan. It took place even with the serum obtained from a patient with agammaglobulinemia, ruling out the possibility of the involvement of Fc-receptors of neutrophils in this phenomenon. Microscopic observation of such SC revealed an increase in the number of neutrophils adhering to the surface of the protein A-coated corneocytes. Ultrastructural observation showed a distinct deformation of the neutrophils adhering to the surface of the corneocytes, suggesting that they are in an activated state. Such an enhanced interaction between protein A-attached SC and neutrophils seems to play an important role in the host defence mechanism against the invading S. aureus and in the production of the characteristic pustules by the neutrophil-mediated damage of the surrounding epidermal tissue.

We report a male infant with Menkes’ disease who showed, at the age of 3 months, slow growth, hair abnormalities such as pili torti and white hair, and low levels of serum copper and ceruloplasmin. The exceptionally bright portions of his hair contained eumelanin and pheomelanin at levels only half those of normal Japanese controls. After subcutaneous administration of copper-histidinate for 2 months, his scalp hair changed to dark brown.

Some pigmentary disorders such as unilateral lentiginosis and vitiligo have a dermatomal or quasidermatomal distribution. This distribution may be the result of abnormalities during fetal skin formation or disturbances in regional peripheral nerves. We describe a case of a previously unreported acquired unilateral pigmentary skin disorder with a dermatomal distribution, in which we found unique degenerative changes in the underlying peripheral nerves as well as at the dermoepidermal junction.

We report a case of Jacquet erosive diaper dermatitis (dermatitis syphiloides posterosiva) in a 9-year-old girl suffering from urinary incontinence due to an ectopic opening of a left double ureter into the vaginal vestibule. The toilet paper that she used as an absorbent was thought to be one of the factors causing the eruption. The lesions cleared with topical application of a nonsteroidal antiinflammatory ointment and zinc oxide ointment, in conjunction with the use of sanitary napkins.

With the aim of characterizing photoreceptor outer segments and obtaining in situ observation of macromolecular variations due to cell types as well as adaption, we counted the number of outer segment disk membranes using electron micrographs of ultrathin sections as well as intramembrane particles on the complementary replicas of the retina of Lampetra japonica. Long photoreceptor cells (LPCs, cone-type cells) numbered 10,000/mm2 in the central as well as peripheral regions, while short ones (SPCs, rod-type cells) numbered 30,000/mm2 in the same regions. The LPC outer segment exhibited 306 disks on average during the light cycle versus 364 during the dark cycle. 12.0% of the LPC disks during the light cycle versus 13.4% during the dark cycle represented the "open" disks. The SPC outer segment exhibited 470 disks on average during the light cycle versus 507 during the dark cycle. 11.1% of the SPC disks during the light cycle versus 13.6% during the dark cycle represented the "open" disks. The LPC disk membrane contained 44.3 particles/0.01 microns 2 during the light cycle versus 39.5 particles during the dark cycle, 95% of which were derived from the protoplasmic fracture (PF) face. The SPCs contained 36.0 particles/0.01 micron 2 during the light cycle versus 43.6 during the dark cycle, 90% of which were derived from the PF-face. The present findings contradict the frequently cited hypothesis that an "open" disk, retaining continuity with the plasmalemma, is preserved characteristically into later stages by the cone outer segment. The significance of the intramembrane particles for the activity of the photoreceptor membrane is discussed.

Macrophage colony-stimulating factor has not been considered as a factor responsible for dendritic cell or Langerhans cell development from hematopoietic progenitor cells. In this study, we examined whether macrophage colony-stimulating factor could be used instead of granulocyte-macrophage colony-stimulating factor for the in vitro development of Langerhans cells from hematopoietic progenitor cells. We replaced granulocyte-macrophage colony-stimulating factor with macrophage colony-stimulating factor from a serum-free culture containing granulocyte-macrophage colony-stimulating factor, stem cell factor, Flt3 ligand, tumor necrosis factor-alpha, and transforming growth factor-beta1. This serum-free culture medium containing macrophage colony-stimulating factor, but not granulocyte-macrophage colony-stimulating factor (macrophage colony-stimulating factor culture), could induce CD1a+ Birbeck granule+ Langerin+ E-cadherin+ factor-like XIIIa Langerhans cells. As a control, the culture of hematopoietic progenitor cells in this culture medium depleted of macrophage colony-stimulating factor or transforming growth factor-beta1 resulted in far fewer or null CD1a+ cells, respectively. Macrophage colony-stimulating factor increased the number of CD1a+ cells in a concentration-dependent fashion. These macrophage colony-stimulating factor-induced Langerhans cells were different from granulocyte-macrophage colony-stimulating factor-induced Langerhans cells in their decreased expression of CD11c and their immature phenotype. The decreased expression of CD11c, however, was recovered by culturing them with granulocyte-macrophage colony-stimulating factor, while they acquired a mature phenotype qby granulocyte-macrophage colony-stimulating factor, tumor necrosis factor-alpha, interleukin-1alpha, or lipo-polysaccharide. Macrophage colony-stimulating factor-induced Langerhans cells could stimulate allogeneic T cells. Interestingly, we could keep the growth and immature phenotypes of macrophage colony-stimulating factor-induced Langerhans cells for at least 28 d of culture. These studies demonstrated that macrophage colony-stimulating factor in cooperation with transforming growth factor-beta1 could induce Langerhans cell development from hematopoietic progenitor cells in vitro without granulocyte-macrophage colony-stimulating factor, which suggests the possibility that macrophage colony-stimulating factor plays a part in the Langerhans cell development in vivo. In addition, the culture using macrophage colony-stimulating factor presents a novel culture system to enable a large-scale and long-term culture of immature Langerhans cells.

The tunica muscularis of the proximal intestine of the loach consisted of intermingling striated and smooth muscle cells without forming any distinct sublayers. Close contacts devoid of intervention by a basal lamina sometimes occurred between these different types of muscle cells. Gap junctions were occasionally found between heterologous as well as homologous muscle cells. In freeze-fracture replicas, striated muscle cells were distinguished from smooth muscle cells by numerous, evenly distributed subsurface caveolae. These were relatively rare and linearly arranged in smooth muscle cells. Variously-sized and -formed aggregations of connexon particles were found in the protoplasmic fracture-face of both muscle cells. Striated muscle cells had aggregates of connexon particles taking the form of either a small solid polygon or an annulus with a particle-free central region. In smooth muscle cells, the particles were arranged either in variously-sized patches or in straight lines. Topologically, heterologous gap junctions observed in ultrathin section were thought to correspond to the small patchy aggregations. Striated muscle cells in the gut had neuromuscular junctions, which differed morphologically from "cholinergic" nerve terminals at neuromuscular junctions of typical skeletal muscle cells. The smooth muscle cells had close apposition with axonal terminals containing many granular vesicles and a variable number of small, clear vesicles. Occasionally, a "cholinergic"-type axonal terminal with a presynaptic active site was found close to a smooth muscle cell.

Histidine decarboxylase (HDC) synthesizes endogenous histamine from histidine in mammals. To evaluate the role of histamine in skin allergic reaction, we used HDC gene knockout mice lacking histamine. No plasma extravasation reaction was observed in HDC-/- mice after passive cutaneous anaphylaxis (PCA) test. Compound 48/80, a mast cell granule depletor, produced plasma extravasation inHDC+/+ mice but no extravasation in HDC-/- mice. Interestingly, orally administered histamine was distributed in the skin in HDC-/- mice and in these histamine-supplemented mice the plasma extravasation reaction was observed after the injection of compound 48/80 and the PCA test. Cultured bone marrow-derived mast cells of HDC-/- mice took up histamine from the histamine-supplemented medium into the secretory granules. The absorbed histamine was released in response to the same antigen and antibody combination used as in PCA test. In contrast to the immediate-type response, the delayed-type hypersensitive response, observed as a thickening of the ear skin after trinitrochlorobenzene challenge (following sensitization), showed no differences between HDC+/+ and HDC-/- mice. Therefore, among the allergic skin reactions, histamine is revealed to be an important mediator especially for the plasma extravasation in an immediate-type allergy model.