Expression of E-cadherin in skin carcinomas

In this study, we investigated the expression of E-cadherin in 31 cases of human skin carcinoma including basal cell carcinoma (BCC), squamous cell carcinoma (SCC), Paget's disease, Bowen's disease (invasive type), and trichilemmal carcinoma, by immunohistochemical staining using a monoclonal antibody specific for E-cadherin. Similar to the E-cadherin expression in normal epidermis, E-cadherin was strongly expressed in all samples of BCC on the cell borders, whereas marked decrease or loss of E-cadherin expression was found in the tumor cells of SCC, Paget's disease, and Bowen's disease (invasive type). On the other hand, E-cadherin expression of trichilemmal carcinoma was slightly reduced. Considering the clinical and histological features of these skin carcinoma, the reduction of E-cadherin expression is considered to be associated with the invasion and metastasis of human skin carcinoma.

Esophageal cancer and aldehyde dehydrogenase-2 genotypes in Japanese males

Although drinking alcohol is an established esophageal cancer risk factor, the mechanisms by which alcohol induces this high-mortality rate cancer are not clear. To help elucidate this problem and develop an implementable preventive strategy, this genetic epidemiological study focused on aldehyde dehydrogenase 2 (ALDH2), the key enzyme for elimination of acetaldehyde generated by alcohol consumption. This enzyme is polymorphic; its mutant allele, ALDH2*2, which leads to the enzyme inactivity, is prevalent in Orientals. This Japanese case-control study of ALDH2-related risk for esophageal squamous cell carcinoma included alcoholics (40 cases and 55 controls) and nonalcoholic drinkers (29 cases and 28 controls). The analysis of the results of genotyping these subjects showed that the increased risk for esophageal cancer in those with one ALDH2*2 allele was substantially higher in both alcoholics (odds ratio = 7.6; 95% confidence interval = 2.8-20.7) and nonalcoholic drinkers (odds ratio = 12.1; 95% confidence interval = 3.4-42.8). The results strongly suggest that because persons who have this mutant ALDH2*2 allele have a high concentration of blood acetaldehyde after drinking alcohol, acetaldehyde (a recognized animal carcinogen) plays a pivotal role in the pathogenesis of alcohol-related esophageal cancer in humans. These results suggest that to help lower their risk for esophageal cancer, persons with the ALDH2*2 allele should be encouraged to reduce their consumption of alcoholic beverages.

Inhibition of NF-AT signal transduction events by a dominant-negative form of calcineurin

An inhibitory, "dominant-negative," form of the calcineurin catalytic (A) subunit was prepared, which lacks the calmodulin-binding domain, autoinhibitory domain and most of its catalytic core but possesses the regulatory (B) subunit binding domain. When tested for its ability to block calcineurin-dependent signaling in Jurkat cells, expression of this "B-subunit knock-out" (BKO) construct suppressed reporter gene activity driven by NF-AT, the pivotal promoter element for interleukin (IL)-2 gene induction. Immunoprecipitation of epitope-labeled BKO demonstrated for the formation of a tight complex with endogenous B subunit in Jurkat cells, consistent with an inhibitory mechanism that involves the sequestration of the B subunit. Furthermore, the sharply reduced NF-AT activity produced by co-transfecting BKO could be "rescued" by overexpression of transfected B subunit, suggesting that depletion of this subunit was responsible for the inhibition. These data suggest the potential utility of agents that disrupt calcineurin-mediated signal transduction pathways by blocking formation of the catalytically active dimer of calcineurin A and B subunits.

Differential subcellular localization of neural isoforms of the catalytic subunit of calmodulin-dependent protein phosphatase (calcineurin) in central nervous system neurons: immunohistochemistry on formalin-fixed paraffin sections employing antigen retrieval by microwave irradiation

We examined the immunohistochemical distribution of the two mammalian isoforms of calcineurin catalyic subunits, A alpha and A beta, in central nervous system (CNS) tissues of cows, rats, and humans. Cryostat sections and paraffin sections of parformaldehyde-fixed tissues were stained with antipeptide antibodies for each isoform. The same localization pattern was observed in both cryostat and paraffin sections. In the latter, the intensity of the staining was dramatically enhanced by microwave irradiation. Calcineurin isoforms were localized in a variety of nerve cells but not in neuroglial cells. Their differential expression as the A alpha isoform in the nucleus and the A beta isoform in the cytoplasm was present in a variety of CNS nerve cells, most distinctively in Purkinje cells of the cerebellum and pyramidal cells of the cerebrum, irrespective of species. These results suggest that each isform has distinct intracellular sites of action in CNS neurons and that the phenomenon has been conserved during mammalian evolution.

Nonsense suppression in mammalian cells

Mammalian cells contain suppressor tRNAs that can translate nonsense codons such as UAG and UGA localized at a specific site of natural mRNAs. For translation of these nonsense codons, a specific secondary or tertiary structure of mRNAs located in the region surrounding the translatable nonsense codon is required. In mammalian cells, transcriptional expression of the tRNA gene encoding UAG suppressor glutamine tRNA is repressed by the binding of a nuclear protein to a specific site in the 5'-flanking region of the gene. Based on these findings, we discuss the translational regulation of nonsense codons in mammalian mRNAs.

Structural feature of the initiator tRNA gene from Pyrodictium occultum and the thermal stability of its gene product, tRNA(imet)

Pyrodictium occultum is a hyperthermophilic archaeum that grows optimally at 105 degrees C. To study how tRNA molecules in P occulrum are thermally stabilized, we isolated the initiator tRNA gene from the organism using a synthetic DNA probe of 74 bp containing the known nucleotide sequences that are conserved in archaeal initiator tRNAs. A HindIII fragment of 700 bp containing the Pyrodictium initiator tRNA gene was cloned and sequenced by cycle sequencing. The nucleotide sequence revealed that the Pyrodictium initiator tRNA gene has no introns, and that the 3'CCA terminus is encoded. The tRNA gene also contained a unique TATA-like sequence, AAGCTTATAA, which is likely the promoter proposed for archaeal rRNA genes, 450 bp upstream of the 5' end of the tRNA coding region. In the region adjacent to the 3' end of the tRNA coding region, there was a sig G-C base pair inverted repeat followed by a C-rich sequence like the p-independent transcription termination signal of bacterial genes. The Pyrodictium initiator tRNA sequence predicted from the gene sequence contained all of the nucleotide residues A1, A37, U54, A57, U60, and U72, in addition to three G-C base pairs in the anticodon stem region, which are characteristic of archaeal initiator tRNAs. The melting temperature (Tm) of the unmodified initiator tRNA synthesized in vitro using the cloned tRNA gene as a template was 80 degrees C, which is only two degrees lower than that calculated from the G-C content in the stem regions of the tRNA. In contrast, the Tm of the natural initiator tRNA isolated from P occultum was over 100 degrees C. Analysis of digests of purified Pyrodictium initiator tRNA by means of HPLC-mass spectrometry and [32P] post-labeling, indicated that the tRNA contains a variety of modified nucleosides. These results suggest that the extraordinarily high melting temperature of P occultum tRNA(Met)i is due to posttranscriptional modification.

[Chest wall reconstruction after the resection of primary chest wall tumors]

Between April 1983 and June 1994, we performed chest wall reconstructions on 9 patients (7 males and 2 females) out of 27 all of whom underwent the radical resection for the primary chest wall tumors. Histological diagnosis of tumors included 6 chondrosarcomas, 1 Ewing's sarcoma, 1 plasmacytoma and 1 giant cell tumor. Six lesions were located on the rib and 3 on the sternum. For the materials for reconstruction of the chest wall use a polyethylene plate in 2 patients, a Marlex mesh in 5 patients and a Marlex mesh with a methyl methacrylate utilizing the sandwich method in 2 patients. The polyethylene plate proved to be satisfactory for maintaining stability of the chest wall. However, our experience using this plate showed intensive foreign body reactions, and discovering these we have not use the polyethylene plate. Marlex mesh had an affinity with human tissue and was very easy to use and produced no complications. We use Marlex mesh for flat surfaces on the anterior or posterior chest wall. Marlex mesh and methyl methacrylate utilizing the sandwich method, combined the solidity and shaping of methyl methacrylate with the benefit such as easy fixation and excellent incorporation of the mesh.

Alpha 1-antichymotrypsin gene polymorphism and risk for Alzheimer's disease

alpha 1-Antichymotrypsin (ACT), a component of the senile plaque of the Alzheimer's disease (AD) brain, has a possible role as a molecular chaperone in developing AD pathology. This study was a search for the possible association of the two structural polymorphisms of ACT, Ala15-->Thr and Met389-->Val in the Japanese population. In 101 AD patients, genotype and allele frequencies of the two polymorphisms did not differ from those of 104 age-matched healthy controls. However, in those subjects in which the apolipoprotein epsilon 4 allele was absent, the frequency of the Ala15 homozygote was significantly higher in the AD patients than in controls. This suggests that the Ala15 homozygote state may be a susceptibility marker for AD, interacting with apolipoprotein E genotype.

Differential expression of gap junction proteins connexin32 and 43 in rat submandibular and sublingual glands

We examined the expression and localization of the gap junction proteins connexin32 and 43 in rat submandibular and sublingual glands. Western blot analysis with anti-connexin32 and 43 antibodies showed bands of approximately 27 KD and 43 KD, respectively, in both glands. Immunofluorescence microscopy demonstrated the presence of reactive spots for connexin32 between acinar cells in both glands. The frequency of connexin32-positive spots in the submandibular glands was approximately equal to that in the sublingual glands. In contrast, reactive spots for connexin43 were observed at the periphery of the alveolar structures in both glands. The connexin43-positive spots in the sublingual glands were more frequent and larger than those in the submandibular glands. No positive spots for both connexins were detected between duct cells in either gland. Immunoelectron microscopy revealed that connexin32 was localized to the gap junctional membranes between acinar cells. Immunolabeling for connexin43 was located on the gap junctions between thin processes of myoepithelial cells. These results suggest that connexin32 of the gap junction is associated with regulation of the secretory function of acinar cells and that connexin43 is associated with that of contraction of the myoepithelial cells in rat salivary glands.

Induction of the low-molecular-weight stress protein HSP27 in organ-cultured normal human skin

To examine the inducibility of 27-kD-molecular-weight heat shock protein (HSP27) in human skin, an indirect immunofluorescence (IF) study was performed on organ-cultured normal human skin by using a monoclonal antibody specific for HSP27. After heat treatment at 45 degrees C for 1 h, nuclear IF was observed in the epidermal cells. When the organ-cultured skin explants were exposed to 10.0 micrograms/ml or 100.0 micrograms/ml 8-methoxypsoralen (8-MOP) for 1 h and then irradiated with UVA (320-400 nm), positive nuclear IF was also observed 6 h after UVA irradiation. Considering these results with the previous reports about HSP72, it appears that, in human skin, HSP27 as well as HSP72 plays an important role in resisting various environmental stresses.

Solution synthesis of human midkine, a novel heparin-binding neurotrophic factor consisting of 121 amino acid residues with five disulphide bonds

Human midkine (hMK), a novel heparin-binding neurotrophic factor consisting of 121 amino acid residues with five intramolecular disulphide bonds, was synthesized by solution procedure in order to demonstrate the usefulness of our newly developed solvent system, a mixture of dichloromethane or chloroform and trifluoroethanol. The final protected 121-residue peptide was assembled from two large fully protected intermediates, Boc-(1-59)-OH and H-(60-121)-OBzl, in CHL/TFE(3:1, v/v) using water-soluble carbodiimide in the presence of HOOBt as coupling reagents. After removal of the protecting groups by HF followed by treatment with Hg(OAc)2 in 50% acetic acid, the fully deprotected peptide was subjected to the oxidative folding reaction. The final product was confirmed to have the correct disulphide structure from its tryptic peptide mapping and to possess the same biological activities as those of the natural product. In order to clarify the active region of the hMK molecule, the N-terminal half domains [(1-59) and (60-121)] were also synthesized by the same procedure used for the hMK synthesis. The C-half domain was confirmed to show the full pattern of bioactivities except for the neuronal cell survival activity, while the N-half one showed much less activity in general.

Over-expression of a new photo-active halorhodopsin in Halobacterium salinarium

The gene of haloopsin (hop) from halobacterial strain shark was cloned and its nucleotide sequence was determined. The deduced amino acid sequence of shark halorhodopsin (HR) showed that its homology with halobium HR was 62%. The gene product seems to be HR having several positively charged residues that are conserved in all known HRs. The gene encoding shark hop as well as that encoding halobium hop were successfully expressed in Halobacterium salinarium (halobium) by using a plasmid shuttle vector containing the bacterioopsin (bop) promoter. The expression level of shark HR is almost the same as that for halobium HR with the same shuttle vector containing the bop promoter. Under the physiological conditions, the anion pumping activity of the shark HR expressed in H. salinarium was almost the same as that for halobium HR; however, the anion selectivity and half-maximal anion transport were different. Furthermore, its absorption maximum in the absence of chloride shifted to approx. 596 nm in contrast to that for halobium HR. The half-lifetimes of HR520 formation for shark HR and halobium HR were almost the same; however, the half-lifetime of its decay was approx. 6-times faster for shark HR than it was for halobium HR at a high chloride concentration (1000 mM). Even at a low chloride concentration (50 mM), HR520 and HR640 intermediates could be detected for shark HR, and the half-lifetime of HR640 decay was found to be approx. 25 ms. In the presence of nitrate, the half-lifetime of HR565 recovery for shark HR was approx. 10-times slower than that for halobium HR. Some of amino acid substitutions between shark HR and halobium HR may affect the anion selectivity and the photoreaction of HR.

Induction of the 72-kD heat shock protein in human skin melanoma and squamous cell carcinoma cell lines

Heat shock proteins (HSPs) or stress proteins comprise a characteristic group of proteins synthesized in cells exposed to heat or other environmental stimuli. Of the many HSPs, the 72-kD heat shock protein (HSP72) is the most stress-inducible one. In the present study, we examined the effects of heat, chemicals (azetidine and sodium arsenite), ultraviolet (UV) light, and gamma-ray irradiation on the induction of HSP72 in cultured human skin melanoma cell lines (P-39 and G-361), a human skin squamous cell carcinoma cell line (HSC-1), and an SV40-transformed human lung fibroblast cell line (WI38VA13) as a control. In these cell lines, heat treatment induced HSP72 more rapidly and intensely than did chemical exposure. Compared with the SCC cell line, the two melanoma cell lines produced less HSP72 with heat treatment. UVC irradiation (20 J/m2) induced HSP72 only in the WI38VA13 cells. After gamma-ray irradiation, no HSP72 induction was detected in any of the cell lines examined. These observations suggest that, in cultured cells, inducibility of HSP72 depends not only on the inducer but also on the origin of each cell line.

A transgenic mouse line with alpha-1,3/4-fucosyl-transferase cDNA: production and characteristics

cDNA of human alpha-1,3/4-fucosyltransferase (Fuc-TIII) was placed under the control of the chicken beta-actin promoter and cytomegalovirus enhancer, then introduced into male pronuclei of fertilized mouse eggs. A transgenic mouse line thus obtained exhibited enhanced expression of Lex (4C9) antigen in endothelial cells located in the glomerulus, sinusoidal capillaries of the liver and capillaries of the heart. Furthermore, in the transgenic mice, sialyl dimeric Lex (FH6) and sialyl Lea (2D3) antigens were strongly expressed in the glomerular endothelial cells.

Efficacy and issues of emergent percutaneous transluminal coronary angioplasty. Comparison of clinical results in younger and elderly patients

The authors investigated the efficacy and prognosis of emergency percutaneous transluminal coronary angioplasty (PTCA) in elderly patients. A study was conducted on the early and late prognosis of the study group composed of 66 younger patients < sixty-five years in Group A and 46 elderly patients > or = seventy years in Group B who underwent reperfusion therapy, including PTCA, for acute myocardial infarction (AMI). No difference was seen in the initial success rate of 82% for Group A and 85% for Group B, or in the vessel patency in the predischarge coronary arteriogram (CAG) with 84% for Group A and 87% for Group B. However, in-hospital mortality was 3% for Group A and 11% for Group B. The patient restenosis rate in the 4.2 months follow-up CAG was 28% for Group A and 50% for Group B. The lesion restenosis rate was 30% for Group A and 53% for Group B (P < 0.05), and the late period mortality rate was 3% for Group A and 11% for Group B. Although there was no difference in the initial success rate of reperfusion through PTCA for AMI in the elderly as compared with the younger patient group, poorer results were seen in the restenosis rate and mortality rate.

Identification of Trp300 as an important residue for Escherichia coli leader peptidase activity

We previously reported that leader peptidase from Escherichia coli was extensively inactivated by reaction with N-bromosuccinimide with concomitant and selective modification of the Trp300 and Trp310 residues [Kim, Y.-T., Muramatsu, T. & Takahashi, K. (1995) J. Biochem. (Tokyo) 117, 535-544]. This indicated that one or both of these tryptophan residues are important for the activity of the enzyme. In order to define further the role of individual tryptophan residues in the activity of leader peptidase, site-directed mutagenesis studies were performed to replace each tryptophan residue with phenylalanine and/or alanine. The replacements of Trp20, Trp59, Trp261, Trp284, and Trp310 with phenylalanine hardly affected the enzyme activity toward a synthetic peptide substrate and the ability to complement the temperature sensitivity of the mutant leader peptidase in E. coli IT41. In contrast, the activity toward the synthetic substrate was significantly decreased by replacement of Trp300 with phenylalanine or alanine. The kcat values of the W300F and W300A mutant enzymes were reduced to 42% and 22%, respectively, of that of the wild-type enzyme, whereas the Km values of these mutant enzymes were almost identical with that of the wild-type enzyme. Moreover, the complementing ability in E. coli IT41 was lost (almost) completely when Trp300 was replaced with phenylalanine or alanine. These results strongly indicate that Trp300 in leader peptidase is important for the catalytic mechanism and/or the construction of the active site structure of the enzyme.

Midkine is a heat and acid stable polypeptide capable of enhancing plasminogen activator activity and neurite outgrowth extension

We studied about the physicochemical stability of a novel heparin-binding growth/differentiation factor, midkine (MK). It was found that synthetic human MK was heat and acid stable. Neither incubation at 80 degrees C for 90 sec nor treatment at low pH affected the elution profile of MK molecule on the high performance liquid chromatography. This physicochemical stability was maintained in the biological activities of MK to enhance plasminogen activator (PA) activity in bovine endothelial cells as well as to promote neurite outgrowth of rat brain cells. A similar stability was observed both with recombinant murine MK and with its homologous protein, recombinant human pleiotrophin. Comparison of physicochemical stability with other several growth factors suggested that MK/pleiotrophin was a unique family of heat and acid stable polypeptides capable of enhancing PA activity and neurite outgrowth.

Structure of the mouse basigin gene, a unique member of the immunoglobulin superfamily

Basigin is a membrane glycoprotein belonging to the immunoglobulin superfamily. The mouse basigin gene was isolated from a genomic DNA library of the BALB/c mouse, and the structure of the gene and its flanking region (11.8 kb) was completely determined. The mouse basigin gene consists of seven exons and six introns spanning 7.5 kb. The distance between the first and second exons is 5.1 kb. The first immunoglobulin-like domain of the basigin molecule is encoded by the second and third exons, and the second immunoglobulin-like domain by the fourth and fifth exons. The fifth exon encodes not only the C proximal portion of the second immunoglobulin-like domain, but also the transmembrane domain and a small portion of the cytoplasmic domain. Thus, the organization of the basigin gene is unique. The 5' upstream sequence of the basigin gene contains no TATA box or CAAT box, but has a CpG-rich island. The BALB/c genomic sequence of all seven exons is consistent with the cDNA sequences of the 129/SV and Swiss mice except several minor substitutions in the 3'-terminal sequence of the 3'-noncoding region. No protein polymorphism has so far been found in basigin of different mouse strains.

Localized cutaneous amyloidosis simulating lichen simplex chronicus

We report a case of localized cutaneous amyloidosis in a 42-year-old Japanese woman. Skin lesions were confined to the nuchal area, and the clinical appearance resembled that of lichen simplex chronicus. Our experience with this case indicates that, in cases presenting with persistent skin lesions simulating lichen simplex chronicus, amyloid should be specifically looked for in biopsy material.

Induction of ovalbumin mRNA by ascorbic acid in primary cultures of tubular gland cells of the chicken oviduct

The present study was conducted to investigate the effects of aging and medium supplements on steroid-induced ovalbumin mRNA in primary cultures of tubular gland cells from the chicken oviduct. In experiment 1, the effect of aging was examined by comparing the responsiveness to administration of estrogen and corticosterone in cells derived from laying hens and estrogen-primed chicks. In experiment 2, the effect of supplementing a culture medium with various compounds on the responsiveness to the steroid treatment was examined. In experiment 3, the effect of supplementing with ascorbic acid was tested in the presence or absence of the steroid hormones. The results indicated that the oviduct cells from immature chicks had clearer induction of ovalbumin mRNA by the steroid treatment than did those from laying hens. Among medium supplements, ascorbate increased the steroid responsiveness to a great extent, and fetal calf serum had modest, but long lasting, induction of ovalbumin mRNA. The drastic induction of ovalbumin mRNA by ascorbic acid supplementation was exerted only when the steroid hormones were present in the medium, implying that the effect of ascorbic acid may be auxiliary in steroid-induced transcription of the ovalbumin gene.

Tau in cerebrospinal fluid: a potential diagnostic marker in Alzheimer's disease

Cerebrospinal fluid from 70 patients with Alzheimer's disease (AD) and 96 patients with non-AD neurological diseases as well as 19 normal control subjects was surveyed by sandwich enzyme-linked immunosorbent assay to quantitate levels of the microtubule-associated protein tau in cerebrospinal fluid. The tau level was significantly increased in AD patients as compared with that in patients with non-AD neurological diseases and control subjects. Increased tau levels were found irrespective of age at onset, apolipoprotein E genotype, and clinical stage. Western blots of AD cerebrospinal fluid proteins revealed two to three tau-immunoreactive bands with an apparent molecular mass between 50 and 65 kd consistent with phosphorylated cerebrospinal fluid tau. Taken together, our results suggest that cerebrospinal fluid tau might reflect the progressive accumulation of altered tau due to the progressive death of neurons in the AD brain, and that the enzyme-linked immunosorbent assay of cerebrospinal fluid tau may prove to be a reliable and early diagnostic test for AD.

Repression of the ovalbumin gene involves multiple negative elements including a ubiquitous transcriptional silencer

Most eukaryotic genes are controlled by a complex array of cis-acting regulatory elements that modulate transcriptional activity. Two major regulatory elements reside in the chicken ovalbumin gene, a steroid-dependent regulatory element (SDRE, -892 to -780) and a negative regulatory element (NRE, -308 to -88). The SDRE is required for responsiveness to estrogen and glucocorticoid. The NRE appears to have the dual role of repressing transcription in the absence of steroids and of cooperating with the SDRE to activate transcription in the presence of steroids. The experiments described herein were designed to investigate the role of the NRE in repressing gene expression. Transfection of OvCAT fusion genes containing deletions in the NRE into primary oviduct cell cultures identified three elements (-308 to -256, -239 to -220, and -174 to -88) that repress transcription. Oligomers corresponding to portions of these elements also independently repress the viral thymidine kinase promoter. Interestingly, the element from -239 to -220 functions mechanistically as a silencer and shares sequence identity with silencers in other genes (TCTCTCCNA). Mobility shift studies indicated that all of the negative elements bind specific protein complexes from oviduct, none of which is appreciably affected by treatment with steroid hormones. However, oviduct-specific proteins bind to the regions from -280 to -252 and from -134 to -88, providing the first identification of potential tissue-specific elements in the ovalbumin gene. These results demonstrate that the region of DNA originally called the NRE is a multifunctional regulatory element that may be involved in several diverse regulatory activities.