Tumor promotion by depleting cells of protein kinase C delta

Tumor-promoting phorbol esters activate, but then deplete cells of, protein kinase C (PKC) with prolonged treatment. It is not known whether phorbol ester-induced tumor promotion is due to activation or depletion of PKC. In rat fibroblasts overexpressing the c-Src proto-oncogene, the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) induced anchorage-independent growth and other transformation-related phenotypes. The appearance of transformed phenotypes induced by TPA in these cells correlated not with activation but rather with depletion of expressed PKC isoforms. Consistent with this observation, PKC inhibitors also induced transformed phenotypes in c-Src-overexpressing cells. Bryostatin 1, which inhibited the TPA-induced down-regulation of the PKCdelta isoform specifically, blocked the tumor-promoting effects of TPA, implicating PKCdelta as the target of the tumor-promoting phorbol esters. Consistent with this hypothesis, expression of a dominant negative PKCdelta mutant in cells expressing c-Src caused transformation of these cells, and rottlerin, a protein kinase inhibitor with specificity for PKCdelta, like TPA, caused transformation of c-Src-overexpressing cells. These data suggest that the tumor-promoting effect of phorbol esters is due to depletion of PKCdelta, which has an apparent tumor suppressor function.

Protein kinase C delta inhibits the proliferation of vascular smooth muscle cells by suppressing G1 cyclin expression

To elucidate the physiological role of protein kinase C (PKC) delta, a ubiquitously expressed isoform in vascular smooth muscle cells (VSMC), PKC delta was stably overexpressed in A7r5 cells, rat clonal VSMC. The [3H]thymidine incorporation in A7r5 overexpressed with PKC delta (DVs) was suppressed to 37.1 +/- 16.3% (mean +/- S.D.) of the level in control or A7r5 transfected with vector alone (EVs). The reduction of [3H]thymidine incorporation was strongly correlated with overexpressed PKC levels. Moreover, transient transfection of a dominant negative mutant of PKC delta restored the reduced proliferation in DVs. Flow cytometry analysis demonstrated that DVs were arrested in the G0/G1 phase of the cell cycle. Expression of cyclins D1 and E and retinoblastoma protein phosphorylation were reduced, while the protein levels of p27 were elevated in DVs as compared with EVs. There were no significant differences in the expression of c-fos, c-jun, c-myc, cyclin D2, D3, cyclin-dependent kinase 2, cyclin-dependent kinase 4, and p21 among the clones. We conclude that PKC delta inhibits the proliferation of VSMC by arresting cells in G1 via mainly inhibiting the expression of cyclin D1 and cyclin E.

Nucleotide sequence analysis of the HLA class I region spanning the 237-kb segment around the HLA-B and -C genes

To elucidate the detailed gene organization of the human leukocyte antigen (HLA) class I region on chromosome 6, seven contiguous cosmid genomic clones covering the 237-kb segment around the HLA-B and -C loci were subjected to DNA sequencing by the shotgun strategy to give a single contig of 236,822 bp from the MICA gene (58.2 kb centromeric of HLA-B) to 90.8 kb telomeric of HLA-C. This region was confirmed to contain four known genes, MICA, HLA-17, HLA-B, and HLA-C, from centromere to telomere. Further, a new member of the P5 multicopy genes was found to be about 1.3 kb upstream of the HLA-17 gene and designated P5.8. Five novel genes designated NOB1-5 were identified by RT-PCR and Northern blot hybridization. In addition, two pseudogenes, dihydrofolate reductase pseudogene (DHFRP) and ribosomal protein L3 homologous gene (RPL3-Hom), were also found in the vicinity of the HLA-B and -C genes, respectively. The two segments (about 40 kb) downstream of the HLA-B and HLA-C genes showed high sequence homology to each other, suggesting that segmental genome duplication including the major histocompatibility complex (MHC) class I gene must have occurred during the evolution of the MHC.

Four primordial modes of tRNA-synthetase recognition, determined by the (G,C) operational code

In distinction to single-stranded anticodons built of G, C, A, and U bases, their presumable double-stranded precursors at the first three positions of the acceptor stem are composed almost invariably of G-C and C-G base pairs. Thus, the "second" operational RNA code responsible for correct aminoacylation seems to be a (G,C) code preceding the classic genetic code. Although historically rooted, the two codes were destined to diverge quite early. However, closer inspection revealed that two complementary catalytic domains of class I and class II aminoacyl-tRNA synthetases (aaRSs) multiplied by two, also complementary, G2-C71 and C2-G71 targets in tRNA acceptors, yield four (2 x 2) different modes of recognition. It appears therefore that the core four-column organization of the genetic code, associated with the most conservative central base of anticodons and codons, was in essence predetermined by these four recognition modes of the (G,C) operational code. The general conclusion follows that the genetic code per se looks like a "frozen accident" but only beyond the "2 x 2 = 4" scope. The four primordial modes of tRNA-aaRS recognition are amenable to direct experimental verification.

Patterns of peripheral enhancement in breast masses: correlation of findings on contrast medium enhanced MRI with histologic features and tumor angiogenesis

PURPOSE

Our goal was to review patterns of peripheral enhancement on contrast-enhanced MRI of the breast and to correlate radiologic findings with pathologic features.

METHOD

We reviewed the MR images of 124 consecutive women with breast lesions. Peripheral enhancement was identified in 35 (32 malignant, 3 benign) lesions. MRI findings were correlated with pathologic features including microvessel density and distribution determined histologically.

RESULTS

Early peripheral enhancement with centripetal progression was seen in invasive carcinomas with a high peripheral and a low central microvessel density, associated with fibrosis and/or necrosis (n = 18; 15 with central fibrosis, 2 with fibrosis and necrosis, and 1 with necrosis alone). Early peripheral enhancement with minimal or no change in enhancement was seen in both malignant (n = 10) and benign (n = 3) lesions. Delayed peripheral enhancement with centrifugal progression was seen in carcinomas that had an expansive growth pattern and a high marginal vessel density with or without a vascularized rim of connective tissue (n = 4).

CONCLUSION

Early peripheral enhancement with centripetal progression appears to be fairly specific for carcinomas, whereas early enhancement with minimal or no centripetal progression, although more common in malignant tumors, may be seen in some benign lesions as well.

MICA gene and ankylosing spondylitis: linkage analysis via a transmembrane-encoded triplet repeat polymorphism

In order to address the possibility that the MICA gene located 47 kb upstream from HLA-B is involved in the pathogenesis of ankylosing spondylitis (AS), we have investigated microsatellite polymorphism in the transmembrane region of MICA in Caucasian patients with AS. The microsatellite allele consisting of 4 repetitions of GCT/AGC was present at significantly higher frequency in the patient group (Pc<0.0000001) than in the ethnically matched control group. However, the frequency of the (GCT/AGC)4 allele was significantly low in the B27-positive patients than in the B27-positive healthy controls (Pc=0.0145). These observations suggest that B27 itself remains the primary genetic marker for AS, although the significantly dissimilar phenotype frequency of the (GCT/AGC)4 allele in B27-positive patients and healthy individuals may reflect the existence of other genetic factor(s) in the HLA-B27 haplotype involved in the development of AS.

Polymorphonuclear leucocyte (PMN) inhibitory factor prevents PMN-dependent endothelial cell injury by an anti-adhesive mechanism

Neutrophil inhibitory factor (NIF), a 41-kD glycoprotein isolated from the canine hookworm, inhibits CD11b/CD18-dependent neutrophil adhesion by binding to CD1lb. We studied the effects of NIF on neutrophil-dependent endothelial cell injury using bovine pulmonary microvessel endothelial cells grown on microporous filters. Endothelial injury was determined as an increase in the transendothelial 125I-albumin clearance rate (a measure of transendothelial permeability). Layering of neutrophils on the endothelial cell monolayer (ratio of 10 neutrophils: 1 endothelial cell) followed by activation of neutrophils with 500 nM of phorbol 12-myristate 13-acetate (PMA) increased transendothelial permeability of albumin by 3- to 4-fold over control monolayers. Pretreatment of neutrophils with NIF at concentrations of 100 nM and above prevented the increased permeability. Pretreatment of neutrophils with the anti-CD18 monoclonal antibody (mAb) IB4 similarly prevented the increase of permeability. Pretreatment of neutrophils with OKM-1, a control isotype-matched mAb directed against an irrelevant epitope on CD11b mAb, did not affect the neutrophil-dependent increase in permeability. NIF reduced the adhesion of neutrophils at concentrations of > or = 100 nM and this effect was abolished by an anti-NIF polyclonal Ab. However, NIF did not prevent the generation of superoxide anions following PMA-induced activation of neutrophils layered on endothelial cell. These findings indicate that NIF inhibits the neutrophil-dependent endothelial injury by preventing CD11b/CD18-mediated neutrophil adhesion, but without altering the oxidant generating capacity of neutrophils interacting with the endothelial cell monolayer.

Identification of a novel HLA-B allele (B*4202) in a Saudi Arabian family with Behçet's disease

A new HLA-B antigen, tentatively called HLA-B42AND, was identified as a B42 serologic variant in a Saudi Arabian family. DNA sequencing analysis of the second and third exon of this new B allele revealed that B42AND was identical to B*4201 except for a single T to C substitution at position 97 of exon 2. This substitution results in histidine (CAC) at codon 9 in B42AND instead of tyrosine (TAC) in B*4201. The antigen frequency of B42AND in a Saudi Arabian population was around 10%. This novel B42AND has officially been named HLA-B*4202.

YSK1, a novel mammalian protein kinase structurally related to Ste20 and SPS1, but is not involved in the known MAPK pathways

To clarify the upstream regulatory mechanism of mitogen-activated protein kinase (MAPK), we performed the reverse transcriptase-based polymerase chain reaction (RT-PCR) with degenerate primers synthesized based on sequences conserved among the kinase domains of yeast MAPK kinase kinases (MAPKKKs), Stell, Bck1, and Byr2. We isolated several mammalian cDNA fragments that encode kinase subdomains sharing significant sequence homology with yeast MAPKKKs. Subsequent screening of a HeLa cell cDNA library using one of these cDNA fragments as a probe resulted in the isolation of a full-length cDNA that encodes a novel protein kinase. The catalytic domain sequence of this gene product is closely related to those of budding yeast Sps1 and Ste20 protein kinases. Thus, we call this protein YSK1 (Yeast Sps1/Ste20-related Kinase 1). The transcript of YSK1 was detected in a wide range of tissues and cells. Immunoprecipitated YSK1 shows protein kinase activity. Although YSK1 is significantly similar in its kinase domain to kinases of the yeast and mammalian MAPK pathways, the overexpression of YSK1 did not lead to the activation of the ERK (extracellular signal-regulated kinase) pathway, JNK (c-Jun NH2-terminal kinase)/SAPK (stress-activated protein kinase) pathway, or p38/Mpk2 pathway. These results suggest that YSK1 may be involved in the regulation of a novel intracellular signaling pathway.

[Ultrastructural study of lens in rat hereditary cataract by quick-freezing and deep-etching]

The cytoskeleton of lens fiber cells in rats with hereditary cataract (ICR/f) was studied by quick-freezing and deep-etching. Two kinds of filamentous structure with diameters of 5 and 10 approximately 15 nm were observed in the cortical fiber cells. They showed meshwork structures which were buried in globular particles. These filamentous structures were mostly absent in the nucleus fiber cells, but aggregated and fused globular particles with diameters of 10 approximately 20 nm were observed. Small cavities were sometimes observed in their cytoplasm. Between lens fiber cells, many globular structures were also seen. These changes might represent the degeneration of the lens fiber cells in cataract lenses.

Improved surgical results after combining preoperative hyperthermia with chemotherapy and radiotherapy for patients with carcinoma of the rectum

PURPOSE

The aim of this study is to evaluate long-term results of preoperative hyperthermia combined with chemotherapy and irradiation (HCR therapy) in patients with carcinoma of the rectum.

METHODS

Postoperative prognoses were compared among 36 patients with carcinoma of the rectum, who were given preoperative HCR therapy followed by surgery, and 52 patients undergoing surgery alone without any preoperative therapy.

RESULTS

There were significant differences in the prognosis between patients given preoperative HCR therapy plus surgery and those having surgery alone, and five-year survival rates were 91.3 and 64 percent, respectively. Particularly, for patients with tumors invading beyond the muscularis propria and/or with positive lymph node metastasis, a significantly longer survival was obtained with HCR plus surgery than in surgery alone (86.5 vs. 50.9 percent and 92.9 vs. 51.7 percent, respectively). However, no significant differences were observed in the postoperative prognosis for cases with no lymph node metastasis and/or with tumors limited to the muscularis propria between these two groups.

CONCLUSIONS

These data clearly demonstrated the effectiveness of preoperative HCR therapy for improving long-term results of patients with carcinoma of the rectum, especially those demonstrating an advanced stage of disease.

An immunocytochemical study of changes in the human erythrocyte membrane skeleton produced by stretching examined by the quick-freezing and deep-etching method

A quick-freezing and deep-etching method in combination with erythrocyte splitting was used to examine the cytoplasmic aspect of whole-mount human erythrocyte membranes. Various external forces induced alterations in membrane skeletal organisation during the splitting procedure. The initial change was elongation in the peripheral part of the membrane skeleton, examined by immunostaining with a monoclonal antispectrin antibody. Under severe stretching conditions, a linear rearrangement of filamentous components was evident; these were disposed parallel to the rim of the erythrocyte, while the central part of the concavity exhibited a more compacted structure. These changes resulted in a different distribution of membrane skeletal components between central rigid and peripheral flexible areas in biconcave erythrocytes. It is suggested that the reversible membrane skeletal changes in the flexible areas which resist the external forces are important for maintaining the normal framework of biconcave human erythrocytes.

[Analysis of the profile of CD4+ cells in Behçet's disease]

The cell-mediated immune response and disorders of the cytokine-producing cells play an important role in the pathogenic mechanisms of Behçet's disease. Recently, CD4+ T helper cells have been categorized into at least two distinct subsets based on their profiles of cytokine production. We analyzed the number of interleukin (IL)-2 producing type 1 helper T (Th1) cells and IL-4 producing Th2 cells from 22 patients (male: 12, female: 10) with Behçet's disease and 19 normal controls (male: 9) by flow cytometric analysis. The patients with Behçet's disease were categorized into two groups by the activity of ocular inflammation; one group comprised the active cases (13 patients) and the other the inactive cases (9 patients). Peripheral blood mononuclear cells (PBMCs) from patients and normal controls were stimulated with immobilized anti-CD3 mAb for 6 hours and immunostained with anti IL-2 and anti IL-4 mAbs followed by fluorescein isothiocyanate (FITC) conjugated 2nd Abs. The number of IL-2 producing CD4+ cells in Behçet's disease patients with active uveoretinitis was significantly higher than that from both inactive cases (p < 0.005) and controls (p < 0.01). In contrast, the number of IL-4 producing CD4+ cells showed no significant difference among the groups. These results may indicate that Th1 cells play an important role in the immunopathogenesis of ocular inflammation of Behçet's disease. Thus, analysis of Th subsets in Behçet's disease may be useful for management of the disease.

Membrane skeletons in avian erythrocytes as revealed by the quick-freezing and deep-etching method

Ultrastructure of chicken erythrocytes were examined by the quick-freezing and deep-etching (QF-DE) method. Some erythrocytes were fixed with paraformaldehyde and prepared with erythrocyte-splitting method or saponin treatment to remove soluble proteins before quick-freezing. Others were prepared in the cytosol buffer with the erythrocyte-splitting method to obtain natural state of cytoskeletons. Non-expanding membrane skeletons were highly condensed on the cytoplasmic side of lipid membrane in the paraformaldehyde-fixed specimens. Under unilateral extension of the specimens, long stretched filaments were connected alternately with condensed filamentous or granular structures under erythrocyte membranes. As the membrane skeletons got closer to the marginal bands, they become more dense network structures. Moreover, in the fresh unfixed specimens, dense networks of filaments were localized underlying erythrocyte membranes in a relatively intact state. Fine filaments connected the marginal microtubule bands to the cytoplasmic sides of erythrocyte membranes. The different distribution of each cytoskeletal component and the association of these structures may support the elliptocytic shape of chicken erythrocytes and resist the dynamic circumstance.

Novel isoform of myotonin protein kinase: gene product of myotonic dystrophy is localized in the sarcoplasmic reticulum of skeletal muscle

It is quite important to know the exact localization and function of myotonin protein kinase (MtPK), identified as the gene product of myotonic dystrophy, the most prevalent disease with multisystem disorders among muscular dystrophies. To investigate the localization of MtPK, we raised a polyclonal antibody against a synthetic peptide chosen within the deduced sequence of MtPK. This antibody detected both a membrane-bound 70-kd protein and a soluble 55-kd protein on Western blots of human muscles. By using this antibody for immunohistochemical studies of both biopsied human skeletal muscle fibers and mature innervated cultured muscle fibers, we can now demonstrate by confocal laser scanning microscopy that MtPK is localized mainly in the I-band. By immunoelectron microscopy, it was determined that MtPK is a membrane-bound protein localized mainly in the terminal cisternae of the sarcoplasmic reticulum. To our knowledge, this is the first documentation of the ultrastructural localization of MtPK. This finding is quite important for clarifying the pathophysiological basis of myotonic dystrophy, which might be due to a dysregulation of calcium metabolism.

Interaction of Nck-associated protein 1 with activated GTP-binding protein Rac

Bacterially expressed glutathione S-transferase fusion proteins containing Rac1 were used to identify binding proteins of this Rho family GTPase present in a bovine brain extract. Five proteins of 85, 110, 125, 140 and 170 kDa were detected, all of which were associated exclusively with guanosine 5'-[gamma-thio]triphosphate-bound Rac1, not with GDP-bound Rac1. The 85 and 110 kDa proteins were identified as the regulatory and catalytic subunits respectively of phosphatidylinositol 3-kinase. Several lines of evidence suggested that the 125 kDa protein is identical with Nck-associated protein 1 (Nap1). The mobilities of the 125 kDa protein and Nap1 on SDS/PAGE were indistinguishable, and the 125 kDa protein was depleted from brain extract by preincubation with the Src homology 3 domain of Nck to which Nap1 binds. Furthermore, antibodies to Nap1 reacted with the 125 kDa protein. Nap1 was co-immunoprecipitated with a constitutively active form of Rac expressed in Chinese hamster ovary cells. The observation that complex formation between activated Rac and PAK, but not that between Rac and Nap1, could be reproduced in vitro with recombinant proteins indicates that the interaction of Nap1 with Rac is indirect. The 140 kDa Rac-binding protein is a potential candidate for a link that connects Nap1 to Rac. The multimolecular complex comprising Rac, Nap1 and probably the 140 kDa protein might mediate some of the biological effects transmitted by the multipotent GTPase.

A protein kinase Cdelta-binding protein SRBC whose expression is induced by serum starvation

West-Western screening of a cDNA expression library using 32P-labeled, autophosphorylated protein kinase Cdelta (PKCdelta) as a probe, led us to identify cDNA clones encoding a PKCdelta-binding protein that contains a leucine zipper-like motif in its N-terminal region and two PEST sequences in its C-terminal region. This protein shows overall sequence similarity (43.3%) to the serum deprivation response (sdr) gene product, and we named it SRBC (sdr-related gene product that binds to c-kinase). PKCdelta binds to the C-terminal half of SRBC through the regulatory domain and phosphorylates it in vitro. In COS1 cells, the phosphorylation of over-expressed SRBC is stimulated by 12-O-tetradecanoylphorbol-13-acetate and further enhanced by the over-expression of PKCdelta. The mRNA for SRBC is detected in a wide variety of cultured cell lines and tissues and is strongly induced by serum starvation. Furthermore, SRBC mRNA is induced during retinoic acid-induced differentiation of P19 cells. These results suggest that SRBC serves as a substrate and/or receptor for PKC and might be involved in the control of cell growth mediated by PKC.

A domain containing the Cdc42/Rac interactive binding (CRIB) region of p65PAK inhibits transcriptional activation and cell transformation mediated by the Ras-Rac pathway

The molecular bases of the versatile functions of Rho-like GTPases are still unknown. Using luciferase assays with rat 3Y1 cells, we found that Rac1 is integrated downstream of Ras in the TRE (TPA response element) activation pathway. Coexpression of a mutant of p65PAK, PAK/RD, lacking the kinase domain but containing the Cdc42/Rac interactive binding (CRIB) region, suppressed the TRE activation and cell transformation caused by constitutively activated forms of Ras (RasV12) and Rac1 (Rac1V12). PAK/RD is a good tool to investigate the signaling pathways in which Rac and Cdc42 are involved.

Serologic survey for HTLV-I in Kanagawa Prefecture

To investigate the seroprevalence of HTLV-I in Kanagawa Prefecture (central Japan), we tested the sera of 8,264 healthy volunteers and 2,414 pregnant women. Of the 8,264 healthy volunteers, 66 (0.80%) were seropositive. The seroprevalence of HTLV-I in the pregnant women was 14/2,414 (0.58%), and this rate was almost identical to that in the healthy female volunteers 15 to 44 years of age (0.59%). These figures indicate that the seroprevalence of HTLV-I in Kanagawa Prefecture is very low and that sexual contact may not be an important contributory factor.

Overexpression of p53 is associated with growth pattern and prognosis in advanced gastric cancer

BACKGROUND/AIMS

The growth pattern of advanced gastric carcinoma, based on volumetric analysis, is closely associated with the biological characteristics of tumors, including DNA ploidy, and is an important prognostic factor. Abnormality of the p53 tumor suppressor gene plays an important role in alteration of cells and possibly leads to cancer development.

MATERIALS AND METHODS

Expression of tumor suppressor gene p53 was investigated immunohistochemically in the primary lesion of 196 patients with advanced gastric cancers, and the relationship of p53 immunopositivity with the growth pattern and prognosis was analyzed.

RESULTS

Positive p53 staining was found in 94 (48%) of the 196 primary carcinomas. Vessel invasions were more frequent and lymph node metastasis was more extensive in p53-positive tumors (p < 0.05), whereas p53 immunopositivity was not associated with depth of cancer invasion nor with the stage of cancer. In the column and mountain type tumors, characterized by vertical or penetrative growth, positive p53 staining was found in 53.8% and 52.9%, respectively. In the funnel type tumor, characterized by superficially spreading growth, positive p53 staining was found in significantly lower incidence (28.9%, p < 0.05). The 5-year survival rates were 44.2% and 25.4% for patients with p53 negative and positive gastric carcinomas, respectively (p < 0.01). Multivariate analysis showed that p53 overexpression was an independent prognostic factor of patients with advanced gastric cancer.

CONCLUSIONS

These findings suggest that p53 gene alteration is associated with less favorable prognosis of advanced gastric cancer, possibly by providing tumors with a potential of vertical growth into the gastric wall.

Characterization of a cartilage-derived 66-kDa protein (RGD-CAP/beta ig-h3) that binds to collagen

A 66-kDa collagen fiber-associated protein (RGD-CAP) was isolated from a fiber-rich fraction of pig cartilage by ultrafiltration and collagen-affinity chromatography. Amino acid sequencing and cDNA cloning indicated that the RGD-CAP is identical or closely related to beta ig-h3 protein which is induced in human adenocarcinoma cells by transforming growth factor-beta (TGF-beta) (Skonier, J., Neubauer, M., Madisen, L., Bennett, K., Plowman, G.D., and Purchio, A.F. (1992) DNA Cell. Biol. 11, 511-522). The RGD-CAP, as well as beta ig-h3, has the RGD sequence in the C-terminal region. The native RGD-CAP bound to type I, II, and IV collagens even in the presence of 1 M NaCl. A recombinant preparation of RGD-CAP expressed in Escherichia coli cells also bound to collagen but not to gelatin. The RGD-CAP mRNA was expressed in chondrocytes throughout all stages, although the expression level was highest during the prehypertrophic stage. In addition, TGF-beta increased the RGD-CAP mRNA level in chondrocyte cultures. Since RGD-CAP transcripts were found in most tissues, this novel collagen-binding protein may play an important role in cell-collagen interactions in various tissues including developing cartilage.

Conformation-dependent activation of type II adenylyl cyclase by protein kinase C

Phorbol ester treatment enhanced the catalytic activity of type II adenylyl cyclase overexpressed in insect cells. In cells coexpressing type II adenylyl cyclase and protein kinase C-alpha, type II adenylyl cyclase catalytic activity was higher even in the absence of phorbol ester treatment; phorbol ester treatment further and markedly enhanced type II adenylyl cyclase catalytic activity. However, this enhancement, either by phorbol ester treatment or by coexpression of protein kinase C-alpha, was lost following membrane solubilization with detergents. This attenuation was unaffected by phosphatase inhibitor or salts. In contrast, membrane solubilization did not affect forskolin-stimulated type II adenylyl cyclase catalytic activity. Purified type II adenylyl cyclase was stimulated by forskolin and Gs alpha, but not by protein kinase C-alpha. Therefore, a specific mammalian protein kinase C isoenzyme can activate type II adenylyl cyclase, but the mechanism clearly differs from that underlying either Gs alpha- or forskolin-mediated stimulation.

Significance of routine annual esophagram for early detection of carcinoma of the esophagus

BACKGROUND/AIMS

In order to achieve increased survival rates for patients with carcinoma of the esophagus, early detection of the disease is vital. Serial esophagrams were evaluated to clarify which interval would be effective for early detection of carcinoma of the esophagus during routine examination.

MATERIALS AND METHODS

One hundred eighty-nine patients with carcinoma of the esophagus were grouped into three, according to the experience and the time of the previous roentgenograms before the definite diagnosis.

RESULTS

Five patients were in Group 1, in which roentgenographic examination had been done within 12 months prior to the diagnosis. Retrospective observation revealed a slight but certain abnormal shadow at the same location as the esophageal tumor seen on the second films. In Group 2, seven had received an esophagram between 12 and 24 months before the diagnosis. In contrast to Group 1, neither abnormality nor findings indicating esophageal tumors were detected on the former x-ray films, in all seven cases. Group 2 was characterized by relatively small tumors and low stage of the disease. Mean tumor length was 4.1 +/- 2.9 cm, and three of seven were classified as Stage I and two as Stage IIA. On the other hand, most of the 177 patients in Group 3, with no previous examination of the esophagus within 24 months before the diagnosis, had far advanced disease. Mean tumor length was 6.3 +/- 2.6 cm. Only nine (5.1%) were classified as Stage I, whereas 115 (65.0%) were classified as Stage III or IV.

CONCLUSION

In light of these data, for populations in which esophageal cancer frequently occurs, esophageal examination every 12 months will no doubt contribute towards the early detection of lesions.

Triplet repeat polymorphism in the transmembrane region of the MICA gene: a strong association of six GCT repetitions with Behçet disease

A member of a novel family of the human major histocompatibility complex (MHC) class I genes termed MIC (MHC class I chain-related genes), MICA, has been recently identified near the HLA-B gene on the short arm of human chromosome 6. The predicted amino acid sequence of the MICA chain suggests that it folds similarly to typical class I chains and may have the capacity to bind peptides or other short ligands. Therefore, MICA is predicted to have a specialized function in antigen presentation or T cell recognition. During nucleotide sequence analyses of the MICA genomic clone, we found a triplet repeat microsatellite polymorphism of (GCT/AGC)n in the transmembrane (TM) region of the MICA gene. In 68 HLA homozygous B cell lines, 5 distinct alleles of this microsatellite sequence were detected. One of them contained an additional one base insertion that created a frameshift mutation resulting in a premature termination codon in the TM region. This particular allele may encode a soluble, secreted form of the MICA molecule. In addition, we have investigated this microsatellite polymorphism in 77 Japanese patients with Behcet disease, which is known to be associated with HLA-B51. The microsatellite allele consisting of 6 repetitions of GCT/AGC was present at significantly higher frequency in the patient group (Pc = 0.00055) than in a control population. Furthermore, the (GCT/AGC)6 allele was present in all B51 positive patients and in an additional 13 B51 negative patients. These results suggest the possibility of a primary association of Behcet disease with MICA rather than HLA-B.