Mutations of p16 and p15 tumor suppressor genes and replication errors contribute independently to the pathogenesis of sporadic malignant melanoma

Mutations of p16 and p15 suppressor oncogenes and the replication errors in six microsatellite loci in sporadic malignant melanomas were analyzed. Four (9.1%) homozygous deletions of both p16 and p15 genes and one point mutation (2.3%) in the p15 gene were detected among 44 primary melanoma samples. One mutation in each of the p16 and p15 genes was observed in ten metastatic lesions. Eight (18.2%) replication errors were detected in three microsatellite loci in the primary melanoma samples, but no replication error was detected in the metastatic samples. None of the samples showed the alteration of p16/p15 genes and the replication errors concomitantly. These results suggest that (1) the homozygous deletions of p16/p15 genes and the replication errors may occur in rather early stages of melanoma tumorigenesis, while the p16/p15 gene mutation may occur in later stages, and (2) the p16 and p15 gene mutations in sporadic malignant melanomas might not be induced by the defect in mismatch repair, implying that p16 as well as p15 gene alterations may play an important role in the pathogenesis of sporadic malignant melanomas.

Analysis of mechanisms of epidermal proliferation induced by intracutaneous injection of cholera toxin by the use of site-specifically mutated cholera toxins

Intracutaneous injection of cholera toxin (CT) into rabbits increases vascular permeability and induces epidermal proliferation. To understand the mechanisms of these effects on the skin, we evaluated the involvement of the ADP-ribosyltransferase activity of the A subunit of CT and receptor-binding interactions between GM1-ganglioside and the B subunit of CT. We constructed two mutant CTs, E112K and W88K, by site-directed mutagenesis. Mutant CT-E112K, in which glutamic acid at position 112 (E112) of the A subunit of CT was replaced by lysine, has been shown to have lost its biological activity on Chinese hamster ovary (CHO) cells because of its abolished ADP-ribosyltransferase activity. Mutant CT-W88K, in which tryptophan at position 88 (W88) of the B subunit of CT was replaced by lysine, has been shown to have lost its binding ability to GM1-ganglioside. Intracutaneous injection of these mutant CTs evoked less vascular permeability and less epidermal proliferation than recombinant wild-type CT. These results suggest that: (1) the ADP-ribosyltransferase activity carried by E112 of the A subunit of CT; and (2) the binding ability to GM1-ganglioside via W88 of the B subunit of CT are essential for these effects of CT on the skin.

Further characterization of a new in vitro angiogenesis model under serum free culture conditions; suppression of endothelial cell differentiation by serum

We studied the regulation of the extracellular matrix in the recently established murine vascular endothelial cell clones, F-2 or F-2C. F-2 cells constitutively show a cobblestone growth pattern under serum supplemented culture conditions, whereas F-2C cells undergo spontaneous histodifferentiation to form tubular structures in chemically defined media. We reported that the tubulogenesis induced by F-2C might relate to the heavy deposition of a 'basement membrane analog' as a subendothelial matrix (SEM). We further characterized the regulation of extracellular matrix (ECM) metabolism in these cell clones, in terms of gelatinase expression, ECM degradation and the effects of serum. F-2C cells in culture medium containing 1% serum did not undergo tubulogenesis but presented cobblestone growth. Zymography analysis showed that both F-2 and F-2C cells express two gelatinase (72 and 92 kDa). However, F-2 cells mainly expressed the former and faintly the latter, whereas F-2C mainly expressed the latter. Proteolysis studies showed that the spent media conditioned by F-2C cells partially cleaved type IV collagen and completely degraded type V collagen. The cleavage of type V collagen was suppressed by the addition of serum, whereas that of type IV collagen was not. The proteolysis of laminin and fibronectin by the conditioned medium was not observed. Serum-supplemented F-2 or F-2C cultures markedly suppressed SEM deposition. These results indicated that F-2C cells under serum free culture conditions not only present a simple and useful in vitro model with which to study the dynamic processes of proteolysis and ECM metabolism during the sequential phases of angiogenesis, but is also useful for analyzing the serum effects on angiogenesis (AG).

Psychosomatic aspects of patients complaining of dizziness or vertigo with orthostatic dysregulation

Eighty-five patients (26 males and 59 females) with orthostatic dysregulation who visited our clinic complaining of dizziness or vertigo between December, 1990 and August, 1996 were analyzed using the Japanese Edition Cornell Medical Index-Health Questionnaire and the Yatabe-Guilford Personality Test. The condition of OD was most commonly noted in 29 patients (34.1%) with dizziness or vertigo of indeterminate etiology, followed by in 14 (16.5%) with Meniere's disease, in ten (11.8%) with hypotension and CNS disorder each, and in 22 (25.9%) with other disorders. The percentage classed as Type III (possible neurotic) or Type IV (probable neurotic), was 46.1% in males and 47.4% in females. The percentage classed as Type B or Type E, suggestive of emotional or psychological disturbance, was 38.5% in males and 37.3% in females. There was good correlation between the Japanese Edition Cornell Medical Index-Health Questionnaire and the Yatabe-Guilford Personality Test results as to psychosomatic aspects. We conclude that, in the treatment of patients with orthostatic dysregulation, it is necessary to consider both physical and psychological aspects of the condition.

Expression of transglutaminase 1 in human hair follicles, sebaceous glands and sweat glands

To explore the function of the enzyme transglutaminase 1 (TGase 1), its distribution was analysed by immunofluorescence microscopy, postembedding immunoelectron microscopy and in situ hybridization. TGase 1 was expressed in the outer root sheath (ORS) cells in the distal portion of the isthmus and infundibulum of human hair follicles. In the level of the proximal and middle portion of the isthmus, TGase 1 was observed in the keratinized area of the inner root sheath (IRS) and ORS cells. In the bulbar and suprabulbar portions, TGase 1 was present in the ORS and IRS cells. The cortex and medulla cells in these regions also contained TGase 1. A high level of fluorescence was observed at the cuticle of the cortex. Sebaceous and sweat gland cells contained abundant TGase 1. Possible functions of TGase 1 in these epidermal appendages are discussed.

Age-related decline in humoral immunity caused by the selective loss of TH cells and decline in cellular immunity caused by the impaired migration of inflammatory cells without a loss of TDTH cells in SAMP1 mice

We investigated the cellular basis of the age-related decline in antibody (Ab) and delayed-type hypersensitivity (DTH) responses to sheep red blood cells (SRBC) in vivo in short-lived senescence-accelerated mouse (SAM) P1. In SAMP1 mice, age-related decreases in CD4+ T cells in the peripheral blood occurred earlier than in control mice and occurred in parallel with the age-related decline in Ab and DTH responses. In addition, the involution of the thymus was faster. The injection of thymic T cells from young mice before sensitization completely restored the Ab responses in aged SAMP1 mice. These data suggest that the age-related decline in Ab response is due to the age-related early loss of helper-T (TH) cells. On the other hand, the local transfer of spleen cells from sensitized aged donors into the footpads of naive syngeneic recipients evoked strong DTH responses, demonstrating the existence of DTH-mediating T (TDTH) cells in the spleens of aged SAMP1 mice. Moreover, the local injection of naive spleen cells from young donors, together with the antigen, into the footpads caused DTH responses in sensitized aged recipients. These findings indicate that TDTH cells were induced and were able to migrate and function as effector cells in aged mice. When naive spleen cells from aged donors were injected locally into the footpad, they restored the DTH response in aged mice, but this effect did not work if the cells were injected intravenously. This demonstrates that the inflammatory cells of the aged mice were able to work at the local site, but could not migrate there. The intravenous injection of naive spleen cells from young donors restored the DTH response in aged mice, suggesting that the endothelial cells of aged mice were not impaired and permitted the inflammatory cells to migrate into the extravascular tissues. Thus, although the age-related decline of the Ab and DTH responses occur in parallel, we found different effects of aging on TH and TDTH cells in SAMP1 mice. Furthermore, our data suggest that the reason for the low DTH response in aged SAMP1 mice is not the loss of TDTH cells, but rather the impaired migration of inflammatory cells into the local site.

Progressive decrease in hair diameter in Japanese with male pattern baldness

Fifty-six Japanese with male pattern baldness were evaluated for changes in their hair diameters over three years. The mean hair diameter significantly decreased each year. The average decrease was 1.1 microns per year. Although the percentage of vellus hair increased by 3.6% over three years, this increase rate was lower than that found in Caucasians. To precisely examine the change in hair diameter, the mean distribution of this diameter was investigated. At the beginning of the study, clear peaks were observed at 95 microns in the twenties and 45 microns in the fifties. The number of thicker hairs decreased and the high frequency peak shifted to a thinner hair diameter over 3 years. To quantify the change in the distribution of hair diameter, the percentage of hairs of more than 60 microns was examined. There was a statistically significant 5.61% decrease in the percentage of hairs with a diameter of more than 60 microns over three years. Our findings suggest that the progression of male pattern baldness in Japanese is slower than that of Caucasians and that the percentage of hairs of more than 60 microns is a sensitive index to evaluate the progression of male pattern baldness and the effects of hair growth or hair loss preventive agents.

Establishment and characterization of a novel in vitro angiogenesis model using a microvascular endothelial cell line, F-2C, cultured in chemically defined medium

The behavior of vascular endothelial cells (EC) is an important factor in the processes involved in angiogenesis, but the regulatory mechanisms of angiogenesis, especially underlying the tubulogenesis by EC are not yet clear. Although a number of in vitro experimental models of tubulogenesis have been developed by use of cultured EC, most of those models are too complex to be easily handled and further, the culture media are usually supplemented with serum, creating problems in interpretation of experimental results. To generate a simple in vitro angiogenesis study model under serum-free culture conditions, we adapted a murine microvascular endothelial cell line, F-2, to a chemically defined medium, Cos Medium 001, and successfully established a subline of F-2, designated F-2C, which revealed a unique growth pattern. In Cos Medium 001, F-2C proliferates in a cobblestone pattern at an early growth stage, but, at a late growth stage, spontaneously differentiates to form three-dimensional honeycomblike tubular structures without the supplementation of any specific factors. The cell aggregation activity of F-2C in the presence of Ca2+ was much greater than that of F-2. The amount of subendothelial matrix deposited by F-2C was significantly higher than that by F-2, and increased prominently after the F-2C cells reached the differentiating stage of tubulogenesis. These findings indicate that F-2C is a new EC line in which tubulogenesis is spontaneously induced by the marked deposition of basement membrane analog to the subendothelial matrix and by the enhancement of presumable cadherin activity. We suggest that this cell line, F-2C, represents a simple and useful in vitro angiogenesis model.

Loss of biological activity due to Glu-->Arg mutation at residue 11 of the B subunit of cholera toxin

Since it has been reported that a single amino acid mutation of Gly-->Arg in the CAGYC region of the beta chain of human thyroid stimulating hormone (hTSH) was responsible for congenital isolated TSH deficiency, and that the same amino acid substitution in this site of hTSH and human chorionic gonadotropin (hCG) introduced by site-directed mutagenesis resulted in loss of activity, the authors studied the role of glutamic acid at position 11 (Glu-11) from the N-terminus of the B subunit of cholera toxin (CT), which corresponds to the glycine in the CAGYC region of the beta chain of hTSH and hCG. A mutant CT constructed by site-directed mutagenesis in which Glu-11 was replaced by Arg (CT-E11R) did not induce either morphological changes or accumulation of cytosolic cyclic AMP in Chinese hamster ovary cells, although it formed the holotoxin AB5, retained the ability to bind to GM1-ganglioside and showed ADP-ribosyltransferase activity. Weak assembly of the B subunits in mutant CT-E11R demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under non-heating conditions might explain the loss of biological activity.

An alanine to proline mutation in the 1A rod domain of the keratin 10 chain in epidermolytic hyperkeratosis

We report a mutation in a case of epidermolytic hyperkeratosis that results in a proline for alanine substitution in the residue position 12 of the 1A subdomain of the keratin 10 chain (codon 158). The disease phenotype is consistent with the inappropriate substitution of a proline near the beginning of the rod domain, because it is likely to seriously disrupt the structural organization of coiled-coil molecules within keratin intermediate filaments. Mutations/substitutions in this position have not been reported in any keratin disease. Position 12 is an alanine in all intermediate filament chains, and lies in the outer b heptad position of the coiled-coil. In vitro peptide interference assembly assays revealed that substitutions that alter residue size or charge at this position primarily interfere with keratin filament elongation.

An autopsy case of angioimmunoblastic T-cell lymphoma with a high content of epithelioid cells in the lymph node: immunohistochemical and genomic analyses

A 79-year-old female developed red papulonodular eruptions on her extremities, facial erythema, generalized lymphadenopathy and high fever. Histopathology of an affected lymph node showed the features of angioimmunoblastic T-cell lymphoma with a high content of epithelioid cells. She died about two years after the onset despite therapy. Genomic Southern blotting and immunostaining of the lymph nodes were performed twice. In August of 1993, Southern blotting did not show any rearrangement of the immunoglobulin or the T-cell receptor (TCR) gene. Small or medium-sized lymphoid cells were positive for CD4 or CD8 (CD4:CD8 = 2:1). However, in September of 1994 (at autopsy), rearrangements of TCK C beta 1, J beta 2 and J gamma genes were observed. Small or medium-sized lymphoid cells were positive for CD4, but negative for CD8. Several large cells were positive for Latent Membrane Protein 1 (LMP1) of the Epstein-Barr virus (EBV). Our results proved that selective oligoclonal proliferation of tumor cells (probably CD4+) accompanied the disease progress.

Moisture-induced drift in thermo-optic phase shifters composed of deuterated and fluorinated methacrylate polymer waveguides

Using deuterated and fluorinated methacrylate polymer waveguides, we fabricated thermo-optic phase shifters that require a small electric power of 10 mW to cause a pi phase shift. The phase shifters had a phase drift that was greater at higher humidity and that was saturated in approximately 10 min. This phenomenon is ascribed to the moisture desorption-sorption of the waveguide polymers caused by heating-cooling on the basis of experimental results on the relationships among waveguide temperature increase, relative humidity, and moisture sorption of the waveguide polymers. This conclusion is supported by the calculation of temperature and moisture distribution in the waveguide when the thin-film heater is heated.

Clinical observations on acute low-tone sensorineural hearing loss. Survey and analysis of 137 patients

We retrospectively analyzed the clinical records of 137 patients who were treated at our clinic for acute low-tone sensorineural hearing loss of unknown cause over a period of 8 years. The analyses of the clinical records indicated the following clinical characteristics: female preponderance; peak incidence during the fourth decade of life; frequent accompanying tinnitus, sensation of ear fullness, and/ or autophony; suspicion of bilateral involvement; and association with autonomic imbalance. The hearing in most of the patients completely recovered, but some selected patients experienced fluctuating hearing loss or progression to Meniere's disease. Our results suggest that a subgroup of patients with severe initial hearing loss should be carefully followed up, although it is difficult to predict the outcome of this disorder.

Three-dimensional cultures of keratinocytes and an application to in vitro-amyloid production of cutaneous amyloidosis

Some three-dimensional culture models of the skin were reviewed including our systems using a collagen dermal substitute and a matrix dermal substitute. No obvious junctional structures, such as hemidesmosomes and the lamina densa, were formed between the basal keratinocytes and the dermal substitutes, when the cytoplasmic membrane of the basal keratinocytes directly faced the collagenous materials. On the other hand, when the cytoplasmic membrane of the basal keratinocytes faced the preformed basement membrane, the type IV collagen film, or the extracellular matrix gel, an organized interaction occurred between the basal keratinocytes and the dermal substitute through hemidesmosomes and a rudimentary lamina densa. Keratinocyte differentiation in the suprabasal layers seemed to be closely related to such a basal cell differentiation. Our preliminary examination of the experimental amyloid production by the epidermal sheet from the lesional skin of patients with primary localized cutaneous amyloidosis suggested that the basal cells in the transplanted lesional epidermis produced amyloid fibrils in our in vitro culture model. This is another use of the three-dimensional culture models of the skin in addition to the application of the systems to wound treatment.

Roles of E- and P-cadherin in the human skin

The Ca(2+)-dependent cell-cell adhesion molecules, termed cadherins, are subdivided into several subclasses. E (epithelial)- and P (placental)-cadherins are involved in the selective adhesion of epidermal cells. E-cadherin is expressed on the cell surfaces of all epidermal layers and P-cadherin is expressed only on the surfaces of basal cells. Ultrastructural studies have shown that E-cadherin is distributed on the plasma membranes of keratinocytes with a condensation in the intercellular space of the desmosomes. During human skin development P-cadherin expression is spatiotemporally controlled and closely related to the segregation of basal layers as well as to the arrangement of epidermal cells into eccrine ducts. In human skin diseases E-cadherin expression is markedly reduced on the acantholytic cells of tissues in pemphigus and Darier's disease. Cell adhesion molecules are now considered to play a significant role in the cellular connections of cancer and metastatic cells. Reduced expression of E-cadherin on invasive neoplastic cells has been demonstrated for cancers of the stomach, liver, breast, and several other organs. This reduced or unstable expression of E- and P-cadherin is observed in squamous cell carcinoma, malignant melanoma, and Paget's disease, but cadherin expression is conserved in basal cell carcinoma. Keratinocytes cultured in high calcium produce much more intense immunofluorescence of intercellular E- and P-cadherin than those cells grown in low calcium. E-cadherins on the plasma membrane of the keratinocytes are shifted to desmosomes under physiological conditions, and therein may express an adhesion function in association with other desmosomal cadherins. Soluble E-cadherins in sera are elevated in various skin diseases including bullous pemphigoid, pemphigus vulgaris, and psoriasis, but not in patients with burns. Markedly high levels in soluble E-cadherin are demonstrated in patients with metastatic cancers.

Clinicopathologic study of leptomeningeal carcinomatosis involving the temporal bone

The temporal bone pathology of a 71-year-old man with bilateral sensorineural hearing loss and facial paralysis caused by diffuse metastatic leptomeningeal carcinomatosis is described. The origin of this malignant disease was an extremely rare entity, a transitional cell carcinoma of the renal pelvis. Histopathologic study of the temporal bone demonstrated that tumor cells filled the internal auditory meatus, infiltrated into the Rosenthal's canals, and reached the scala tympani of the basal turn of the bilateral cochleas. The vestibulocochlear nerve and facial nerve trunks in the internal auditory meatus had been destroyed by the bilateral tumor invasion. Case reports of temporal bone metastases of leptomeningeal carcinomatosis published since 1965 were reviewed. In leptomeningeal carcinomatosis, it is suggested that tumor cells infiltrate the internal auditory meatus of both ears simultaneously from the cerebrospinal fluid, involving the seventh and eighth nerve trunks, and then cause bilateral sensorineural hearing loss and facial paralysis.

Histidine-44 of the A subunit of Escherichia coli enterotoxin is involved in its enzymatic and biological activities

We examined the role in toxicity of histidine-44 of the A subunit of Escherichia coli enterotoxin, which is located in the active site cavity close to glutamic acid-112. Although amino acid substitution of histidine-44 usually renders a mutant toxin unstable to trypsin, one mutant, alanine-44 (His44Ala) was found to be stable. His44Ala did not show any agmatine:ADP-ribosyltransferase activity in the presence or absence of recombinant ADP-ribosylation factor. It showed no diarrheal or rabbit skin permeability activity and was a competitor in enterotoxin-ADP-ribosyltransferase assays containing recombinant ADP-ribosylation factor. These results suggest that like glutamic acid-112, histidine-44 plays an essential role in toxicity. A tentative model, which explains NAD+ catalysis and the transfer of the ADP-ribosyl moiety to a target amino acid, is proposed for histidine-44 and glutamic acid-112.

In vivo evidence of the critical role of cadherin-5 in murine vascular integrity

Vascular endothelial cell-cell adhesion is crucial for the regulation of vascular functions and is associated with many circulatory disorders. We isolated a rat monoclonal antibody (VECD1) recognizing the mouse vascular endothelial cell adhesion molecule and found that it inhibited vascular endothelial cell-cell association. We sequenced a full-length cDNA of the antigen that was identical to mouse cadherin-5. L-cells transfected with its cDNA acquired cell-cell adhesiveness, and these transfectants reacted with VECD1 at cell-cell contact areas. We studied the role of mouse cadherin-5 in vascular functions. The addition of VECD1 antibody to a cultured vascular endothelial cell line (F-2) caused the detachment of each cell. Although normal F-2 cells formed tubular structures on Matrigel, VECD1 disturbed the tubulogenesis. VECD1 also increased the permeability through the F-2 cell layer. To clarify the in vivo function of mouse cadherin-5, we intraperitoneally injected the hybridomas producing VECD1 into adult mice. Severe venous stasis and subcutaneous hemorrhage were induced within several days after the injection, resulting in the early death of the animals. These findings are evidence of an essential role of cadherin-5 in the regulation of vascular endothelial cell-cell adhesion in vivo.

Multiple cadherins are expressed in human fibroblasts

Although the cell-cell adhesiveness of fibroblasts is thought to be related to wound healing, the molecular basis of this adhesiveness is still unknown. We isolated five kinds of cadherin fragments from the cDNA of human fibroblasts by polymerase chain reaction (PCR). Two of the five were known cadherins: PC43, a protocadherin containing six cadherin repeats in the extracelluar domain, and human Fat, which is the human homologue of the Drosophila tumor suppressor Fat. The other three were novel cadherin fragments, and we named them cadherins FIB1, FIB2, and FIB3. The expressions of cadherins including E-, P-, and N-cadherin, PC43, human Fat, and cadherins FIB1, FIB2, and FIB3 were compared in human fibroblasts, human melanocytes, and human epidermal keratinocytes. The latter six cadherins were expressed in human fibroblasts, and cadherins FIB1 and FIB2 were fibroblast-specific. These results suggest that diverse cadherin molecules may contribute to the cell-cell adhesion in human fibroblasts.

Identification of novel cadherins expressed in human melanoma cells

Cadherin molecules are essential for tissue morphogenesis and are also related to cancer invasion and metastasis. Although normal melanocytes express E- and P-cadherin, the activity and expression of E- and P-cadherin in melanoma cells are still unknown. We measured the homophilic adhesion activity of human normal epidermal melanocytes and the melanoma cell lines MeWo and A375. The melanoma cells showed stronger homophilic adhesion activity than did the melanocytes, despite the lower expression of E- and P-cadherin in the melanoma cells. This result suggested that melanoma cells expressed other types of homophilic adhesion molecules. Using degenerate primers to amplify multiple cadherin subtypes, we performed a polymerase chain reaction (PCR) with the first strand of cDNAs generated by reverse transcription of the mRNAs of the melanoma cells, and we isolated two known cadherin fragments, N-cadherin and PC42, and six novel cadherin fragments, cadherins ME1-ME6. The reverse transcriptase-PCR using specific primers of cadherins including E-, P-, and N-cadherins, PC42, and cadherins ME1-ME6 revealed that the melanoma cells expressed more kinds of cadherin molecules than did the melanocytes. Such cadherins may play an important role in melanoma cell-cell adhesion.

Bromodeoxyuridine-induced expression of endothelin A in A375 human melanoma cells

Expression of endothelin (ET) receptor subtypes was examined in an experimental model of A375 human melanoma cell differentiation using the pyrimidine analog bromodeoxyuridine (BUdR). BUdR (10 microM)-treated cells had an increased surface area and an increased dendricity, were contact-inhibited and lacked tumorigenecity in athymic nude mice. The untreated A375 cells exclusively expressed ETB and BUdR-induced phenotypical changes were accompanied by induction of ETA expression as evidenced by northern blotting, [125I]ET-1 binding assay and [Ca2+]i measurement. Thus, BUdR-induced differentiation of A375 melanoma cells may provide a model system to study the receptor subtype switch in melanocyte development.

Mosaic expression of uncein and 180-kDa bullous pemphigoid antigen in generalized atrophic benign epidermolysis bullosa

Immunofluorescence microscopy of epidermodermal junction components in serial cryosections from the perilesional skin of a patient with generalized atrophic benign epidermolysis bullosa (GABEB) showed broken line-like staining of both BPAG2 (180-kDa bullous pemphigoid antigen) and uncein (antigen of 19-DEJ-1 monoclonal antibody), whereas integrin alpha 6 and laminin 5 were continuously expressed along the basement membrane zone. Immunoelectron microscopy revealed a mosaic distribution of the BPAG2/uncein positive and negative cells. BPAG2, a candidate protein of GABEB, probably has a close connection with uncein, and anchoring filament component.

Increase in radiation sensitivity of human malignant melanoma cells by expression of wild-type p16 gene

The influence of wild-type p16 expression on the radiation sensitivity of human melanoma cell lines was investigated. MeWo cells, which alone expressed intrinsic wild-type p16 among six melanoma cell lines examined, showed higher radiosensitivity in comparison with the other five melanoma cells. The introduction of human wild-type p16 cDNA into A875 cells, which homozygously lost p16 genes, and AKI cells, which retained p16 gene but did not express p16 mRNA, led to increased sensitivity of those cells to X-ray irradiation. The radiosensitizing effect by the p16 introduction to those cells was prominent after rather higher doses of X-rays (8 and 10 Gy). In both A875 and AKI, no significant difference in sensitivities to UVC and cisplatin was observed between the parental and p16-transfectant cells. These results suggest that the loss or dysfunction of p16 gives melanoma cells the radioresistant characteristics.

Human melanoma cells generate leukotrienes B4 and C4 from leukotriene A4

We examined the synthesis of leukotrienes (LTs) in human melanoma cells in order to assess the function of LTs in human melanocytes. LTA4 hydrolase, which catalyzes the conversion of LTA4 to LTB4, was detected in the supernatant of cultured human melanoma (MeWo) cells and melanoma cells obtained from patients. Immunoblotting analysis using an antihuman LTA4 hydrolase antibody showed LTA4 hydrolase to be a 70-kDa protein in both MeWo and melanoma cells. Considerable activity of LTC4 synthase, which catalyzes the conversion of LTA4 to LTC4, was detected in the microsomal fraction of both MeWo and melanoma cells. The HPLC profile of the LTC4 synthase reaction products revealed that LTC4 was the main product. LTD4 was not detected under these conditions, indicating that the microsomal fraction of human melanoma cells lacks the membrane-bound gamma-glutamyl transferase that converts LTC4 to LTD4. LTC4 synthase activity was inhibited by the addition of MK-886, and was not altered by treatment with N-ethylmaleimide or 1-chloro-2,4-dinitrobenzene. These results indicate that the enzyme responsible for the conversion of LTA4 to LTC4 in human melanoma cells is LTC4 synthase rather than a nonspecific or microsomal glutathione-S-transferase. These results also suggest that human melanoma cells can generate LTB4 and LTC4 from LTA4, and that this process is catalyzed by two enzymes: LTA4 hydrolase and LTC4 synthase.

OX40 expressed on fresh leukemic cells from adult T-cell leukemia patients mediates cell adhesion to vascular endothelial cells: implication for the possible involvement of OX40 in leukemic cell infiltration

We demonstrated previously that OX40 and its ligand, gp34, directly mediate adhesion of activated normal CD4+ T cells, as well as human T-cell leukemia virus type I (HTLV-I)-transformed T cells to vascular endothelial cells. In the present study, we examined expression of OX40 on fresh leukemic cells from patients with adult T-cell leukemia (ATL) and its possible involvement in cell adhesion. Flow cytometric analysis showed that peripheral blood mononuclear cells (PBMC) or lymph node tumor cells from 15 of 17 cases expressed significant levels of OX40 without stimulation. On the other hand, gp34 was not expressed on these cells, although its expression is also known to be associated with HTLV-I-infection. In Western blot analysis, a 50-kD protein band was detected by anti-OX40 monoclonal antibody (MoAb) in two ATL cases examined, as well as phytohemagglutinin (PHA) blasts and Hut102, an HTLV-I-infected T-cell line, but not in resting PBMC or Jurkat. Expression of OX40 mRNA was shown by reverse transcriptase-polymerase chain reaction in all ATL cases tested, PHA-blasts, and Hut102, but not in resting PBMC or Jurkat. We could not detect expression of HTLV-I viral mRNA in any of the cases tested. Cell adhesion assay was performed and in at least three cases, fresh ATL cells exhibited adhesion to human umbilical vein endothelial cells that could be considerably inhibited by either anti-OX40 MoAb or anti-gp34 MoAb. Immunohistochemical staining of skin biopsy specimens indicated that infiltrating mononuclear cells express OX40 in vivo. Taken together, these data indicate that leukemic cells from most, but not all, ATL patients constitutively express OX40, which may play a role in leukemic cell infiltration in addition to cell adhesion in vivo.

Werner's syndrome--chromosome analyses of cultured fibroblasts and mitogen-stimulated lymphocytes

Two cases of Werner's syndrome are reported. Fibroblasts derived from both patients revealed reduced population doubling numbers. Chromosomal analyses for fibroblasts from both patients and lymphocytes from one patient revealed that chromosomal aberrations occur frequently and randomly. Although some of the chromosomal aberrations involved sites where tumour suppressor genes have been mapped, neither of our patients demonstrated malignancy. Chromosomal aberration at one critical site may not be sufficient to induce cancer or additional factors may be necessary.

The relationship between psychosomatic factors and orthostatic dysregulation in young men

We carried out a questionnaire survey regarding symptoms of orthostatic dysregulation and administered the Japanese Edition of the Cornell Medical Index-Health Questionnaire (JCMI) and the Yatabe-Guilford Personality Test (Y-G test) to 151 male medical students (mean age, 24.6 yr). Orthostatic dysregulation was identified in 19 (12.5%) of the subjects based on the questionnaire results. The percentage classed as types III (possible neurotic) and IV (probable neurotic) according to the health questionnaire was 47.3% in the 19 with orthostatic dysregulation and 8.9% in the controls (n = 78). The percentage classed as types B and E, suggestive of emotional or psychological disturbance according to the personality test, was 42.1% in those with orthostatic dysregulation and 8.9% in the controls. These differences were significant (P < 0.01). These results suggest that psychosomatic factors influence the occurrence of orthostatic dysregulation in young men.

Evoked potentials in patients with chronic respiratory insufficiency

P300, somatosensory evoked potential (SEP) and brainstem auditory evoked potential (BAEP) are widely used neurophysiological methods for objectively evaluating cognitive, somatosensory and brainstem auditory functions. We studied the P300, SEP and BAEP in 17 patients with chronic respiratory insufficiency (PaO2:58.2 +/- 7.0 mmHg; mean +/- SD) and 15 age-matched healthy subjects (PaO2: 84.4 +/- 11.3 mmHg). The latency and amplitude of P300, the N9 latency, N9-N13 and N13-N20 interpeak latencies (IPL) in SEP, wave I latency and I-V IPL in BAEP were compared between the patients and controls. The P300 latency, N9-N13 and N13-N20 IPLs in SEP in the patients were significantly prolonged compared to the controls. In contrast, the amplitude of P300, N9 latency in SEP, wave I latency and I-V IPL in BAEP were not significantly different between the patients and controls. These results suggest that chronic respiratory insufficiency influences the cognitive and somatosensory functions, and indicate that there is a selective vulnerability of evoked potentials to this condition.

Foot ulcer due to arteriovenous malformation: report of a case

A 41-year-old woman had erosive eruptions surrounded by irregularly shaped pigmentation on the lateral aspect of her right foot, where she had noted gradually increasing warmth and pain for 10 years. The eruptions waxed and waned without complete healing, and an ulcer which had formed one year previously did not respond to topical treatments. Arteriography performed on the right lower extremity disclosed multiple diffuse arteriovenous malformations in the right lower leg and foot. The ulcer was treated by bed rest, surgical debridement, and topical application of bucladesine sodium ointment. After three months, the ulcer healed, leaving a shallow scar and pigmentation.

Prenatal determination of human platelet antigen type 4 by DNA amplification of amniotic fluid cells

To predict a fetus at risk for neonatal alloimmune thrombocytopenia (NATP) caused by human platelet antigen (HPA)-4 incompatibility, we applied a sequence-specific polymerase chain reaction (PCR-SSP). We were able to determine the HPA-4 genotype of three infants at risk using amniotic fluid cells without the need for fetal blood sampling. The HPA-4 genotypes of amniotic fluid cells determined in this way were completely concordant with the genotype and phenotype of infants' venous blood samples obtained after delivery. Therefore, this technique is also convenient to a fetus at risk in the antenatal management of NATP induced by HPA-4 incompatibility.

A unique DNA sequence of human enterotoxigenic Escherichia coli enterotoxin encoded by chromosomal DNA

We detected Ent plasmids in 300 strains of human enterotoxigenic Escherichia coli, but one strain, E. coli 240-3, had neither a small nor a large plasmid and encoded the heat-labile enterotoxin (LTh(240-3)) gene on its chromosome. DNA sequences showed that LTh(240-3) differed by 12 and 14 base pairs from LT (LTh) and LT (LTp) from human H10407 and porcine EWD299 strains, respectively. In deduced precursor toxins, LTh(240-3), LTh and LTp differed from LTh, LTp and LTh(240-3) at nine, eight and eleven positions, respectively. These data suggest that although LTh(240-3) encoded in the chromosome is antigenically similar to LTh, it cannot be grouped with LTh due to differences in its DNA and amino acids sequences.

Mitogen-inducible SIPA1 is mapped to the conserved syntenic groups of chromosome 19 in mouse and chromosome 11q13.3 centromeric to BCL1 in human

Sipa1, previously called Spa1, is transcriptionally induced in the murine lymphoid cells following mitogenic stimulation and encodes a protein with a domain related to Rap1 GTPase activating protein (Rap1GAP) at the N-terminus and to PEST sequences followed by a leucine zipper motif at the C-terminus. Herein mouse genomic Sipa1, which consisted of 16 exons, was cloned. Gene linkage analysis using (BXD) recombinant inbred strains indicated that Sipa1 was mapped to the most centromeric region of chromosome 19 syntenic with the long arm of human chromosome 11. Human SIPA1 cDNA exhibited a striking homology to that of mouse throughout the entire region, with the overall identity being 90% at the amino acid level. Human genomic clones, which hybridized with both mouse and human SIPA1 cDNA but not with RAP1GAP cDNA, were then isolated. Fluorescence in situ hybridization (FISH) analysis using the human genomic clones indicated that SIPA1 was indeed mapped to chromosome 11q13, most likely to the 11q13.3 subregion. It was further indicated by double-color FISH that SIPA1 was located in the centromeric neighborhood of CCND1/ PRAD1, a presumed BCL1 oncogene.

Involvement of tumor necrosis factor-alpha, interleukin-1 beta, interleukin-8, and interleukin-1 receptor antagonist in acute lung injury caused by local Shwartzman reaction

A local Shwartzman reaction (LSR) was prepared in rabbit lung as a model of acute lung injury. To induce LSR, intratracheal injection of lipopolysaccharide (LPS) 10 micrograms into the lower lobe of the right lung, followed 24 h later by i.v. injection of LPS (10 micrograms/kg). In the lung with the LSR, myeloperoxidase activity, representing neutrophil accumulation, peaked at 1-2 h and was sustained for 48 h after challenge with i.v. LPS. The lung water content peaked at 12 h, and decreased gradually. Histological findings showed diffuse interstitial widening, intra-alveolar leukocyte infiltration with hemorrhage, and alveolar exudate formation. The production of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), interleukin-8 (IL-8), and IL-1 receptor antagonist (IL-1 Ra) in the lung was analyzed. TNF-alpha first elevated and peaked at 0.5 h (66.5 +/- 16.7 ng/g.lung), subsequently, IL-1 beta and IL-8 increased and peaked at 2 h (17.8 +/- 3.4 ng/g.lung and 336.9 +/- 49.6 ng/g.lung, respectively). IL-1Ra was present even before the challenge, and the production increased to show a dual peak (0.5 h, 1.5 +/- 0.2 micrograms/g.lung; and 2 h, 1.6 +/- 0.1 micrograms/g.lung), and a large concentration of IL-1Ra was sustained for 48 h. Immunohistochemistry showed that the cellular source of these cytokines was alveolar macrophages and infiltrating neutrophils. Thus, disclosing the kinetics of the generation of cytokines led to a better understanding of their roles, namely TNF-alpha as an initiator, IL-1 and IL-8 as amplifier and effector, and IL-1Ra as regulator of the intensity of acute inflammation.

Age-related changes in the compound action potentials of the eighth nerve in guinea pigs

The eighth nerve compound action potential (CAP) in 95 guinea pigs was measured using click stimuli to investigate age-related changes in their neural auditory thresholds. The animals were separated into three groups: group A (n = 43, 86 ears; 2-4 months old); group B (n = 29; 58 ears, 13-15 months old); and group C (n = 23; 46 ears, 23-25 months old). With increasing age, a gradual elevation of CAP thresholds was clearly seen among the three groups. The negative peak (N1) latencies of the CAP were prolonged, and the N1 amplitudes of the CAP decreased. There were significant differences in N1 latencies among the three groups and in N1 amplitudes between groups A and B, and between groups A and C. However, the rate of decline of the thresholds as well as the input-output function curves of the CAP varied in some of the oldest animals, suggesting that there were some individual differences in degenerative aging processes of the auditory system.

The relationship between orthostatic dizziness and hypotension in male medical students

We carried out a questionnaire survey regarding symptoms of orthostatic dysregulation (OD) and administered the Schellong test (orthostatic test) to 123 normal male medical students aged 21-29 years to investigate the relationship between orthostatic dizziness and hypotension. OD was identified in 15 (12.2%) of the subjects based on the questionnaire results. Orthostatic dizziness was noted in 40.7% of the subjects (50/123). The occurrence of orthostatic dizziness was most significantly related to systolic pressure decrease during the procedure for the Schellong test. These results suggest that the testing procedure introduced by Schellong can be useful, and clinically applicable to the assessment of orthostatic dizziness, since it presents the advantage of being simple enough to carry out in clinical practice.

Electrophysiologic effects of nitrous oxide, a volatile anesthetic, in dogs following myocardial infarction in comparison with other anesthetics

The present study was undertaken to examine the electrophysiologic effects of nitrous oxide in the dog heart after inducing myocardial infarction, and to compare these with those of other anesthetics. Myocardial infarction was produced by two-stage ligation of the left anterior descending coronary artery in dogs. Seven days after ligation, bipolar electrodes were sutured on the ventricular surface of the infarcted and normal regions for applying electrical stimulation or recording ventricular activation. Ventricular activation time and QT interval on the bipolar electrocardiogram and PQ interval from the standard limb lead II were measured during atrial pacing. Nitrous oxide 80% did not significantly prolong ventricular activation time, PQ interval or QT interval. However, halothane 1 minimum alveolar concentration (MAC), thiopental 5 and 10 mg/kg and fentanyl 30 microg/kg did prolong ventricular activation time; thiopental and fentanyl prolonged the QT interval. Nitrous oxide did not potentiate the effects of fentanyl. Therefore, electrophysiologic effects of nitrous oxide are much weaker compared with those of thiopental, fentanyl or halothane.

Flow cytometry analysis of the Fas ligand expression of activated lymph node T-cells

There is increasing evidence for the role of the Fas/Fas ligand interaction in the immunoregulation of T-cells. We studied the expression of the Fas ligand (FasL) in activated peripheral T-cell in vitro, and its relation to autonomous cell death by flow cytometry. Following the stimulation of lymph node T-cells with anti-CD3 and rIL2, the mRNA level of FasL increased more than four times during the first 2 days over the level before stimulation. The surface expression of FasL was observed on 27% of the population at day 2 after stimulation and increased to approximately 50% at day 3. Kinetic analysis by flow cytometry, however, indicated that all T-blasts transformed during activation did not express FasL. FasL expression became evident simultaneously with the termination of cell expansion. Since cells remained viable (> 90%) at day 3 as judged by trypan blue-exclusion, cell membranes expressing FasL were supposed to be still intact. Concomitantly with FasL-expression, spontaneous DNA fragmentation was observed. These observations support the idea that autonomous Fas/FasL interaction mediates apoptosis in activated peripheral T-cells as demonstrated in T-cell hybridoma or established T-cells.

8-hydroxy-2'-deoxyguanosine is increased in epidermal cells of hairless mice after chronic ultraviolet B exposure

8-Hydroxy-2'-deoxyguanosine (8-OHdG) is a mutation-prone (G:C to T:A transversion) DNA base-modified product generated by reactive oxygen species or photodynamic action. G:C to T:A transversions are observed in the p53 and ras genes of UVB-induced skin cancers of mice and in squamous and basal cell carcinomas of human skin exposed to sunlight. In the current study, 8-OHdG formation was evaluated in the epidermis of hairless mice after repeated exposure to UVB, and possible mechanisms involved were studied. Exposure of hairless mice to either 3.4 [2 minimal erythema dose (MED)] or 16.8 (10 MED) kJ/m2 of UVB three times a week for 2 wk induced a 2.5- or 6.1-fold increase, respectively, in the levels of 8-OHdG in DNA, compared to the unexposed controls. An immunohistochemical method using a monoclonal antibody specific for 8-OHdG showed stronger and more extensive staining in the nuclei of UV-irradiated epidermal cells than in those of nonirradiated cells. Western blots probed with antibodies against 4-hydroxy-2-nonenal-modified proteins confirmed the involvement of reactive oxygen species in the epidermal damage induced by chronic UVB exposure. 3-Nitro-L-tyrosine was detected in western blots in a concentration-dependent manner, suggesting that peroxynitrite derived from the reaction of nitric oxide and superoxide, both of which were probably released from inflammatory cells, was involved in modifying the DNA bases. Therefore, the formation of 8-OHdG after UVB exposure appears to be regulated by at least three pathways: photodynamic action, lipid peroxidation, and inflammation and may play a role in sunlight-induced skin carcinogenesis.

The amino acids of Escherichia coli enterotoxin B subunit involved in binding to Bio-Gel A-5m or to the glycoprotein from mouse intestinal epithelial cells

We determined whether Arg13, Met31, and Ser95 of the heat-labile enterotoxin B subunit (LT-B) might be involved in Lt-B binding to oligosaccharides, which did not bind to the B subunit of the cholera toxin (CT-B). Three LT-B mutants, R13H, M31L, and S95A were prepared by substituting three amino acid residues that differ in CT-B. These mutants formed a pentamer and exhibited the same binding ability to the GM1 ganglioside as native LT-B. Although these mutants did not bind to Bio-Gel A-5m, they did bind to the glycoprotein from mouse intestinal cells in the order R13H > M31L > S95A. These data suggest that Ser95, Met31, and Arg13 are important for LT-B binding to Bio-Gel A-5m, and that although Ser95 is also partially responsible for LT-B binding to the glycoprotein, Arg13 has no significant involvement in it.

Immunolocalization of peptide 19 and other calcium-binding proteins in the guinea pig cochlea

Calcium ions are known to play critical roles in a variety of cochlear functions. The distributions of a number of calcium binding proteins that regulate calcium ion levels within the cochlea have previously been described. In this report we extend and refine previous reports of the distribution of immunostaining for calmodulin, calbindin, and calretinin and show for the first time the distribution for peptide 19. There were longitudinal and radial gradients of immunostaining for peptide 19 within outer hair cells that appeared to match previously described gradients of efferent innervation of these cells. Gradients of immunostaining for calbindin within outer hair cells were in the opposite directions, which suggests that levels of this protein are correlated with afferent innervation density and perhaps the abundance of subsurface cisternae. No gradients were seen in the distributions of cells stained for calmodulin and calretinin, which included sensory cells and supporting cells respectively. All ganglion cells were stained for calmodulin but the other proteins appeared to be present in limited ganglion cell subpopulations. In addition to staining of sensorineural elements, antisera to all compounds but peptide 19 showed immunostaining of cells within the lateral wall and the spiral limbus. The results suggest that the proteins under study are involved in a wide variety of calcium-regulated functions within the cochlea. Knowledge of the unique distribution of each of the compounds should facilitate further studies of their roles in cochlear function.

[Neurophysiological studies of minamata disease with HTLV-I associated myelopathy--a case report]

In both Minamata disease (MD) and HTLV-I associated myelopathy (HAM), sensory disturbance is one of the most characteristic clinical symptoms. We have examined median nerve SSEPs (MN-SEP) and posterior tibial nerve SEPs (PTN-SEP) of both patient groups, and reported their specific abnormalities. MN-SEP of MD patients never showed any conduction delay nor conduction block at the cervical cord. However, they demonstrated the initial positive cortical response with low amplitude instead of the initial negative response (N20) seen in healthy subjects. In PTN-SEP, MD patients showed the initial positive cortical response with significantly shorter latency and lower amplitude than healthy subjects. These findings have never been seen in any other diseases. On the other hand, the conduction delay and conduction block on peripheral nerve, spinal cord and/or intracranial sensory tracts have been demonstrated in many cases with HAM. The patient was a 60-year-old man. About 40 years ago, he suffered with typical clinical symptoms of MD such as cerebellar ataxia, intention tremor and sensory disturbance of upper and lower extremities, and then his condition was complicated with progressive spastic paraplegia and urinary bladder dysfunction since 30 years ago. Both MN-SEP and PTN-SEP were studied so that we could make the electrophysiological differential diagnosis of MD and HAM. His MN-SEP indicated both the conduction delay at his cervical cord and intracranial sensory tract and the initial positive potential from cephalic recording. Furthermore, his PTN-SEP demonstrated severe conduction block at the spinal cord and neither cervical response (N28) nor cortical response (P37) was evoked. In conclusion, the clinical electrophysiologic studies supported our notion that the case might be affected with both MD and HAM.