[Early phase II clinical study of KW-2307 in patients with lung cancer. Lung Cancer Section in KW-2307 Study Group]

A multicenter early Phase II clinical study of KW-2307, a new vinca alkaloid derivative, in patients (pts) with lung cancer was conducted in 15 hospitals. Ninety-seven pts were enrolled, among whom 95 were eligible. Seventy of the eligible pts had non-small cell cancer (NSCLC) and 25 had small cell cancer (SCLC). PR was obtained in 13 (18.6%) of NSCLC pts and 3 (12%) of SCLC pts. Only those who had no previous chemotherapy showed PR in NSCLC pts, and the response rate in these pts was 29.5% (13/44). As to the correlation between dosage and tumor effect, a better effect was exhibited at higher doses, with response rates of 21.7% (5/23) and 38.1% (8/21) at 20 mg/m2 and 25 mg/m2, respectively. The major adverse effect of this drug was leukopenia (neutropenia), which was Grade 3 or 4 in many cases. Recovery from this complication, however, was rapid. Other adverse effects included mild hepatic dysfunction, anorexia, nausea/vomiting, fever, general fatigue, phlebitis and constipation. The incidence of peripheral nervous disorder such as the paresthesia commonly observed with vinca alkaloids, was as low as 10%, and the symptoms, if any, were mild.

HLA-DR alleles in patients with Sjögren's syndrome over-representing V beta 2 and V beta 13 genes in the labial salivary glands

To identify genetic factors that play a role in the pathogenesis of patients with SS over-representing V beta 2 and V beta 13 genes in the lips, HLA-DR and -DQ alleles of 10 primary SS patients with predominant expression of V beta 2 and V beta 13 genes in the lips were analysed, using the polymerase chain reaction (PCR) and sequence specific oligonucleotide probes. The CDR3 amino acid sequences of cDNA clones encoding V beta 2 and V beta 13 genes were also determined by PCR. The results showed that the DRB4*0101 allele was significantly increased (80%) and that the frequency of DRB3 allele was decreased (0%) when compared to findings in healthy subjects (35.6 and 26%, respectively). Sequencing analyses demonstrated that 75% of V beta 2 cDNA clones and 87% of V beta 13 cDNA clones had a glutamine residue at position 106, in the CDR13 region. Moreover, the conserved sequences (Y*TLRNEQ) in the CDR3 of V beta 13-positive T cell were detected in two different clones (27%) from the two individual SS patients. These findings suggest that the decreased DRB3 and increased DRB4*0101 alleles may be associated with the antigens recognized by V beta 2- and V beta 13-positive T cells.

Purification and characterization of nuclear phospholipase C specific for phosphoinositides

A phosphoinositide-specific phospholipase C (PLC) was solubilized from the isolated nuclei of rat ascites hepatoma AH7974 cells by ultrasonication in 2 M KCl. The extract was then subjected to five steps of column chromatographies in the order of Sephacryl S-300, phosphocellulose, Mono Q, Mono S, and Superose 6. Four forms of PLC (tentatively designated as N1, N2, N3, and N4) were purified 440-1400-fold. N1, N2, N3, and N4 showed apparent molecular masses of 85, 83, 80, and 88 kDa, respectively, on SDS-polyacrylamide gel electrophoresis. N1 cross-reacted with the antibody against the delta 1 isoform, while the other three forms did not cross-react with any of the antibodies against PLC-delta 1, -gamma 1, -gamma 2, and -beta 1. They hydrolyzed phosphatidylinositol (PI), phosphatidylinositol 4-monophosphate (PIP), and phosphatidylinositol 4,5-bisphosphate (PIP2) but did not show any activities against phosphatidylcholine and phosphatidylethanolamine. They showed the same optimal pH:pH 6.5 for PI hydrolysis and pH 7.0 for both PIP and PIP2 hydrolyses. They absolutely required Ca2+ for activity, with optimal concentrations of 10(-3)-10(-5) M for PIP and 10(-4)-10(-5) M for PIP2. For PI hydrolysis, N1, N2, and N3 required a Ca2+ concentration higher than 10(-2) M whereas N4 revealed significant activity even at 10(-5) M Ca2+ concentrations. Two forms of plasma membrane PLC and three forms of cytosolic PLC were purified from AH7974 cells by the same procedure as for nuclear PLC. Comparative study with these three groups revealed that all of the purified PLC isoforms shared similar enzymological properties except N4, which showed an exceptionally high affinity to Mono S column and was active at low concentrations of Ca2+ for PI as substrate. Furthermore, when PLC isoforms of nuclei from adult resting rat liver were compared with those from regenerating rat liver after partial hepatectomy, a PLC isoform corresponding to N4 of AH7974 cells was found only in regenerating liver nuclei. From these results, it was suggested that the nuclei of growing liver cells possessed a unique form of PLC (N4).

Platelet-derived growth factor is a potent stimulator of expression of intercellular adhesion molecule-1 in human arterial smooth muscle cells

The effects of platelet-derived growth factor (PDGF) on the expression of intercellular adhesion molecule-1 (ICAM-1) as an indicator of cell activation were investigated in cultured human arterial smooth muscle cells (SMC). PDGF-BB and -AB but not -AA at 2-10 ng/ml stimulated ICAM-1 expression at a subconfluent but not a confluent state in a dose-dependent manner. ICAM-1 expression was induced at 2h, reached a plateau at 4h, and continued for at least 24h after stimulation with PDGF. The maximal stimulatory effect of PDGF-BB at 10 ng/ml was comparable to that by optimal concentrations of other cytokines and inflammatory agents. These data suggested that PDGF was a potent stimulator of ICAM-1.

DNA polymerase alpha overcomes an error-prone pause site in the presence of replication protein-A

Eukaryotic DNA polymerase alpha pauses at some sites on the natural DNA template of M13mp2. Terminal misincorporations of dA or dG, in place of dT, by DNA polymerase alpha have been reported to be within one of the pause sites, pause site II (positions 6269 and 6270 (Fry, M., and Loeb, L.A. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 763-767)). The DNA products arrested within pause site II (position 6270) were separated, annealed with synthetic templates, and further elongated by DNA polymerase alpha. It was confirmed that a considerable amount of terminal misincorporation of dG in place of dT occurred at this position. When M13mp2 DNA was coated with various amounts of replication protein-A (RP-A), however, DNA polymerase alpha was able to overcome the pause site II, whereas pause bands at other sites barely decreased. In contrast, Escherichia coli single-stranded DNA-binding protein did not specifically abolish the arrested band at pause site II, though it generally suppressed the reaction. Since RP-A hardly increased the elongation frequency from the primer carrying a 3'-mismatched terminal deoxynucleotide, the reduction of arrested products by RP-A may be attributed to the change in the incorporation mode from noncomplementary to complementary deoxynucleotides within pause site II and may not be due to the reinitiation from the mismatched 3'-terminal deoxynucleotide. To confirm this, we amplified the reaction products at pause site III by means of a polymerase chain reaction method and showed that the complementary strand to pause site II, which was elongated in the presence of RP-A, did not carry any detectable misinsertion. Therefore, the errorprone step of the DNA synthesis catalyzed by DNA polymerase alpha may be readily avoided by RP-A.

Observation of the highly organized development of granule cells in rat cerebellar organotypic cultures

Cerebellar slices of 9-day-old rats were cultured for a week at the interface between air and a culture medium containing horse serum and hormone cocktail, and the development of granule cells was characterized morphologically. The typical layered structure of the cerebellar cortex was well preserved during the cultivation. Many granule cells in the external granular layer (EGL) proliferated actively within the early culture period. They were migrating downward at 3 days in vitro (DIV) and almost completed the migration to the internal granular layer (IGL) after 6 DIV. In the middle and upper molecular layer (ML), parallel fibers were elongated horizontally, which is the orientation 90 degrees rotated compared to that in vivo. They formed synapses with Purkinje cell dendrites. Regional differences in synapse density and maturity existed which might reflect a gradient in progressive synapse formation comparable to that in vivo. Thus, a serial process of highly organized development of granule cells was realized for the first time in vitro, although some spatial or temporal modifications existed. Such a culture system could be a useful experimental model for the study of cellular and molecular mechanisms of spatiotemporally organized neuronal development.

Inductions of oxidative DNA damage and mesothelioma by crocidolite, with special reference to the presence of iron inside and outside of asbestos fiber

Inductions of oxidative DNA damage (oh8dG) in vitro and peritoneal mesothelioma in rats (F344, female) were compared between crocidolite (CR) and de-ironized crocidolite [DCR, washed by HCl and ethylenediamine tetraacetic acid (EDTA)] to verify the hypothesis that reactive oxygen species contribute to carcinogenesis, focusing on the role of iron present inside or outside of the CR. The yield of oh8dG was 14.6 oh8dG/10(5)dG in CR and 30.2 in DCR under simple incubation with DNA. In the incubation systems added several chemicals and H2O2, DCR induced higher levels of oh8dG than CR. Especially, the addition of Fe2O3 and H2O2 to DCR increased oh8dG in DNA depending on the Fe2O3 concentration, however, this tendency was not observed in the same system of CR. Surprisingly, 7 out of 10 rats died within 2 days after the injection of 10 mg of Fe2O3 following the DCR injection (5 mg/rat), showing necroses of hepatocytes from the surface of each lobe where CR and Fe2O3 particles had been deposited together. There was no death in other groups of rats. One year after the i.p. injection of CR (5 mg/rat, single injection), mesotheliomas were found in all rats administered DCR and Fe2O3 (2 mg/rat, once a week, for 35 weeks), in 4 rats of DCR alone (n = 10), in 5 rats of CR alone (n = 10) and in none of the rats administered Fe2O3 alone (n = 10). Therefore, present results indicate that the induction of oxidative DNA damage changed even when the same type of asbestos was washed by chemical treatment, and Fe2O3 promoted the development of mesothelioma which was induced by DCR.

Low Temperature-Induced Cytoplasmic Acidosis in Cultured Mung Bean (Vigna radiata [L.] Wilczek) Cells

Cold-induced changes in vivo in the cytoplasmic pH of suspension-cultured cells of mung bean (Vigna radiata [L.] Wilczek) were investigated by fluorescence-ratio imaging cryomicroscopy with special reference to the variations in the chilling sensitivity of cells during the growth cycle. Because of the preferential localization of the fluorophore in the cytoplasm under specified conditions and the ideal response of fluorescence to pH, fluorescein diacetate allows measurements to be made of temporal changes in cytoplasmic pH at low temperature. A remarkable difference was demonstrated in the cold-induced changes in cytoplasmic pH between cells at the early and late stages of exponential growth. The cells at the early stage of exponential growth were most sensitive to chilling, and the cytoplasmic pH decreased dramatically within a short period of incubation at 0[deg]C, decreasing from 7.4 to 6.8 after 4 h and to 6.3 after 18 h. The cells at the late stage of exponential growth were chilling tolerant, and no significant decrease in the cytoplasmic pH was observed during the incubation at 0[deg]C for 24 h or even longer. From the results presented here, it appears that cold-induced cytoplasmic acidosis is characteristic of chilling-sensitive mung bean suspension-cultured cells.

Sexual dimorphism of age-related changes in whole-body fat distribution in the obese

We performed a cross-sectional study using whole-body computerized tomographic (CT) scans in order to clarify age-related changes in whole-body fat distribution in both genders. The subjects were 66 men and 96 women, whose body mass index (BMI) was over 25 kg/m2. CT scans were performed at seven levels (head, fore-arms, upper arms, chest, abdomen, thighs and calves), and the fat volumes of the segments were calculated from the cross-sectional areas of the fat tissues. After calibrating to the total fat volumes, the relationship between age and the relative segmental fat volumes was analysed. In both genders, the relative intra-abdominal visceral fat volume increased and that of the legs decreased with age. The relative abdominal subcutaneous fat volume decreased with age only in male subjects. The increase in the relative visceral fat volume with age was about 2.6 times larger in males than in pre-menopausal females, while post-menopausal females showed the same increase as male subjects. These data suggest that there is a definite gender difference in the age-related changes in whole-body fat distribution, especially in the abdominal fat tissues. In addition, the accumulation of visceral fat is markedly accelerated by menopause in women.

[Analysis of epitopes for TSH receptor autoantibodies using TSH receptor/LH-CG receptor chimeras]

Graves' disease and idiopathic myxedema are autoimmune thyroid diseases and are caused by thyrotropin (TSH) receptor autoantibodies, thyroid stimulating antibody (TSAb) in Graves' disease and thyroid stimulation blocking antibody (TSBAb) in idiopathic myxedema. Studies with TSH receptor/lutropin-chorionic gonadotropin (LH-CG) receptor chimeras show that binding sites or epitopes on human TSH receptor for TSH, TSAb and TSBAb are different and, moreover, epitopes for TSAb are heterogeneous in different Graves' patients. Epitopes for TSAb exist in the N-terminal region and those for TSBAb in the C-terminal region on human TSH receptor extracellular domain.

Role of vascular cell adhesion molecule 1/very late activation antigen 4 and intercellular adhesion molecule 1/lymphocyte function-associated antigen 1 interactions in antigen-induced eosinophil and T cell recruitment into the tissue

To determine the role of vascular cell adhesion molecule 1 (VCAM-1)/very late activation antigen 4 (VLA-4) and intercellular adhesion molecule 1 (ICAM-1)/lymphocyte function-associated antigen 1 (LFA-1) interactions in causing antigen-induced eosinophil and T cell recruitment into the tissue, we studied the effect of the in vivo blocking of VCAM-1, ICAM-1, VLA-4, and LFA-1 by pretreatment with monoclonal antibodies (mAb) to these four adhesion molecules on the eosinophil and T cell infiltration of the trachea induced by antigen inhalation in mice. The in vivo blocking of VCAM-1 and VLA-4, but not of ICAM-1 and LFA-1, prevented antigen-induced eosinophil infiltration into the mouse trachea. On the contrary, the in vivo blocking of VCAM-1 and VLA-4, but not of ICAM-1 and LFA-1, increased blood eosinophil counts after antigen challenge, but did not affect blood eosinophil counts without antigen challenge in sensitized mice. Furthermore, the expression of VCAM-1 but not ICAM-1 was strongly induced on the endothelium of the trachea after antigen challenge. In addition, pretreatment with anti-IL-4 mAb decreased the antigen-induced VCAM-1 expression only by 27% and had no significant effect on antigen-induced eosinophil infiltration into the trachea. The in vivo blocking of VCAM-1 and VLA-4 inhibited antigen-induced CD4+ and CD8+ T cell infiltration into the trachea more potently than that of ICAM-1 and LFA-1. In contrast, regardless of antigen challenge, the in vivo blocking of LFA-1, but not of ICAM-1, increased blood lymphocyte counts more than that of VCAM-1 and VLA-4. These results indicate that VCAM-1/VLA-4 interaction plays a predominant role in controlling antigen-induced eosinophil and T cell recruitment into the tissue and that the induction of VCAM-1 expression on the endothelium at the site of allergic inflammation regulates this eosinophil and T cell recruitment.

[The effect of preclotting and collagen coating on endothelializing rate and thrombogenesity of Dacron grafts in the canine thoracic aorta]

Although high porosity knitted Dacron is generally recognized to have superior healing characteristics over woven Dacron, its porosity must be controlled at the clinical operation. This can be achieved with several materials, including geratin, insoluble collagen, albumin, and fibrin. We made atherocollagen coated graft using EX-313 as a new crosslinking agent. The purpose of this study is to compare the endothelializing rate and thrombogenesity of Dacron grafts coated by atherocollagen in the canine thoracic aorta with preclotting grafts with blood or albumin. Five groups were studied: Control group (n = 10), without preclotting; A-P group (n = 8), preclotting with albumin; B-P group (n = 5), preclotting with blood; W-C group (n = 5), atherocollagen coating with low cross-linkage; S-C group (n = 7), atherocollage coating with high cross-linkage. Thoracic aorta was replaced with 8 mm graft in length of 5.0 to 5.5 cm using temporary bypass with anthron tube. Grafts were harvested 3 months following implantation, and the endothelized surface ratio was calculated by microscopic line sampling method. Endothelized surface ratio of Control group, A-P group B-P group, W-C group and S-C group were 85%, 55%, 67%, 93% and 85%, respectively. Endothelized surface ratio of W-C group and S-C group were higher (p < 0.05) than those of A-P group, B-P group. There were thrombus in non-epithelized area. We conclude that atherocollagen coated graft had superior antithrombogenesity compared to albumin or blood preclotting graft.

In vivo bronchodilator action of a novel K+ channel opener, KC 399, in the guinea pig

We evaluated the in vivo bronchodilator effects of KC 399, a novel K+ channel opener. In anesthetized guinea pigs, i.v. administration of KC 399 (1-10 micrograms/kg), BRL38227 (lemakalim, 10-100 micrograms/kg) and salbutamol (0.3-3 microgram/kg) evoked a dose-related reduction in the histamine-induced bronchoconstriction. The dose of KC 399 producing a 50% inhibition of the bronchoconstriction induced by histamine was 2.6 (1.9-3.6) microgram/kg. In exerting this action, KC 399 was approximately 13 times more potent than BRL38227, but approximately 4 times less potent than salbutamol. The bronchodilator action of i.v. KC 399 (10 micrograms/kg) lasted for over 30 min, whereas that induced by either BRL38227 (100 micrograms/kg) or salbutamol (3 micrograms/kg) lasted less than 10 min. When given by inhalation, KC 399 (1-30 micrograms/ml) induced a more prolonged effect and was a more potent bronchodilator than BRL38227 (0.3-1 mg/ml) in the histamine-induced bronchoconstriction model. Inhaled KC 399 (30 and 100 micrograms/ml) also prevented the antigen-induced bronchoconstriction in sensitized guinea pigs under anesthetic. When given by the oral route, KC 399, BRL38227 and salbutamol protected conscious guinea pigs from asphyxic collapse in response to inhaled histamine, their effective doses being 0.03, 1 and 3 mg/kg, respectively. From these in vivo experimental results, we conclude that KC 399 is an orally active, potent and long lasting bronchodilator.

Expression of sequences homologous to HTLV-I tax gene in the labial salivary glands of Japanese patients with Sjögren's syndrome

OBJECTIVE

To address the question of whether the human T cell leukemia virus type I (HTLV-I) gene is associated with the etiology of Sjögren's syndrome (SS).

METHODS

RNA expression of HTLV-I gag, pol, env, and tax genes in labial salivary glands (LSGs) from SS patients who were seronegative for antibodies to HTLV-I was examined using reverse transcription and polymerase chain reaction techniques.

RESULTS

The HTLV-I tax gene, but not the HTLV-I gag, pol, or env genes, was detected in LSG samples from 4 of 14 patients (29%). The nucleotide sequences of the HTLV-I pXIV region in these 4 patients' LSGs showed 100% homology to the HTLV-I pXIV gene from the MT-2 cell line.

CONCLUSION

These findings suggest that products encoding sequences homologous to the HTLV-I pXIV gene in SS patients' LSGs might be candidates for self-antigen and/or lead to activation of autoreactive T lymphocytes through trans-acting transcriptional activation.

Sulfate- and sialic acid-containing glycolipids inhibit DNA polymerase alpha activity

The effects of various glycolipids on the activity of immunoaffinity-purified calf thymus DNA polymerase alpha were studied in vitro. Preincubation with sialic acid-containing glycolipids, such as sialosylparagloboside (SPG), GM3, GM1, and GD1a, and sulfatide (cerebroside sulfate ester, CSE) dose-dependently inhibited the activity of DNA polymerase alpha, while other glycolipids, as well as free sphingosine and ceramide did not. About 50% inhibition was achieved by preincubating the enzyme with 2.5 microM of CSE, 50 microM of SPG or GM3, and 80 microM of GM1. Inhibition was noncompetitive with both the DNA template and the substrate dTTP, as well as with the other dNTPs. Since the inhibition was largely reversed by the addition of 0.05% Nonidet P40, these glycolipids may interact with the hydrophobic region of the enzyme protein. Apparently, the sulfate moiety in CSE and the sialic acid moiety in gangliosides were essential for the inhibition since neither neutral glycolipids (i.e., glucosylceramide, galactosylceramide, lactosylceramide) nor asialo-gangliosides (GA1 and GA2) showed any inhibitory effect. Furthermore, the ceramide backbone was also found to be necessary for maximal inhibition since the inhibition was largely abolished by substituting the lipid backbone with cholesterol. Increasing the number of sialic acid moieties per molecule further enhanced the inhibition, while elongating the sugar chain diminished it. It was clearly shown that the N-acetyl residue of the sialic acid moiety is particularly essential for inhibition by both SPG and GM3 because the loss of this residue or substitution with a glycolyl residue completely negated their inhibitory effect on DNA polymerase alpha activity.

Detection of point mutations in the K-ras oncogene at codon 12 in pure pancreatic juice for diagnosis of pancreatic carcinoma

BACKGROUND

Mutations in the K-ras oncogene at codon 12 are detected at a remarkably high frequency in pancreatic carcinomas and are believed to be a critical event in oncogenesis. The authors attempted to detect K-ras mutations in DNA obtained from pure pancreatic juice collected endoscopically, as a novel diagnostic approach to pancreatic carcinoma.

METHODS

K-ras mutations were examined using the two-step polymerase chain reaction (PCR) combined with restriction enzyme digestion, followed by nonradioisotopic single-strand conformation polymorphism (SSCP) analysis.

RESULTS

Specific mutations of the K-ras gene at codon 12 were found in six of nine (67%) duct cell carcinomas, all of which were negative by cytodiagnosis of the same pure pancreatic juice. K-ras mutations were not detected in the pancreatic juice from 14 healthy control subjects, 10 patients with chronic pancreatitis, or 3 patients with islet cell tumors.

CONCLUSIONS

Detection of K-ras mutation at codon 12 in pancreatic juice is highly specific for diagnosing pancreatic duct cell carcinoma and may be a valuable diagnostic modality for pancreatic carcinoma and for differentiating chronic pancreatitis from carcinoma.

Genetic interactions among genes involved in the STT4-PKC1 pathway of Saccharomyces cerevisiae

Loss of yeast protein kinase C function results in three distinct phenotypes: staurosporine sensitivity, cell lysis and blockage of cell cycle progression at the G2/M boundary. Genetic analysis of the PKC1/STT1 protein kinase C gene and its interactions with STT4, encoding an upstream phosphatidylinositol 4-kinase, and BCK1, encoding a downstream protein kinase, reveal that they form part of a single pathway. However, the BCK1-20 mutation (a gain-of-function mutation of BCK1) or overexpression of PKC1 cannot suppress all of the phenotypes caused by the loss of STT4 function, strongly suggesting the existence of a branch point between STT4 and PKC1. We also describe the MSS4 gene, a multicopy suppressor of the temperature-sensitive stt4-1 mutation. MSS4 is predicted to encode a hydrophilic protein of 779 amino acid residues and is essential for cell growth. Based on genetic and biochemical data, we suggest that MSS4 acts downstream of STT4, but in a pathway that does not involve PKC1.

Development of egg fragments of the ascidian Ciona savignyi: the cytoplasmic factors responsible for muscle differentiation are separated into a specific fragment

The eggs of ascidians contain cytoplasmic determinants responsible for differentiation of larval muscle cells. However, the molecular nature and mode of action of muscle determinants are unknown at present. To establish an appropriate experimental system for studying muscle determinants, we have devised a method for separating the determinants into specific egg fragments. The treatment of unfertilized eggs of Ciona savignyi with cytochalasin B followed by centrifugation yielded (1) a large, nucleated red fragment, (2) a small, enucleated black fragment, (3) a small, enucleated clear fragment, and (4) a small, enucleated brown fragment. When inseminated, only red fragments cleaved and developed into so-called "permanent blastulae," in which the differentiation of epidermal cells was evident. However, when red fragments were fused with black fragments and the fusion products were inseminated, the fusion products showed a remarkable ability to express muscle-specific markers. In addition, the ability of black fragments to promote the expression of muscle-specific markers was evident when the fragments were fused with presumptive-epidermis blastomeres. In contrast, clear and brown fragments showed limited ability to promote muscle differentiation. These results suggest that the muscle determinants are present in unfertilized eggs and that the determinants are concentrated into black fragments and depleted from red fragments. These two fragments may serve as an appropriate experimental system to determine the molecular nature of muscle determinants in ascidian eggs.

T and R states in the crystals of bacterial L-lactate dehydrogenase reveal the mechanism for allosteric control

The crystal structure of L-lactate dehydrogenase from Bifidobacterium longum, determined to 2.5 A resolution, contains a regular 1:1 complex of T- and R-state tetramers. A comparison of these two structures within the same crystal lattice and kinetical characterization of the T-R transition in solution provide an explanation for the molecular mechanism of allosteric activation. Substrate affinity is controlled by helix sliding between subunits which is triggered by the binding of the activator, fructose 1,6-bisphosphate. The proposed mechanism can explain activation by chemical modification and mutagenesis, as well as suggesting why vertebrate counterparts are not allosteric.

Mortality among inhabitants of an HTLV-I endemic area in Japan

A community-based cohort study was conducted to clarify the risk of human T-cell leukemia virus type I (HTLV-I) infection for cause-specific deaths. A total of 1,997 individuals (751 men and 1,246 women) aged 30 or older in A-Island, Nagasaki Prefecture, Japan who had voluntarily attended annual mass health examinations, including serum HTLV-I antibody test, were followed up for a mean period of 5.3 years. In a Cox proportional hazards analysis adjusted for age at baseline, the HTLV-I seropositivity was found to be associated with mortality from all causes in men (hazard ratio (HR) 1.89; 95% confidence interval (CI) 1.01-3.54) and women (HR 1.94; 95% CI 1.16-3.22). When the effects of 2 deaths (1 man and 1 woman) from adult T-cell leukemia/lymphoma (ATL) were excluded, the mortality risk decreased slightly but was still significantly or marginally significantly greater than 1 in both men (HR 1.77; 95% CI 0.93-3.37) and women (HR 1.87; 95% CI 1.12-3.12). Further analysis of cause-specific deaths revealed a significant increase in the risk for non-neoplastic diseases but not for neoplasms excluding ATL. These findings suggest that long-term HTLV-I infection represents a health hazard greater than just that for the development of ATL. It was difficult, however, to draw a conclusion regarding the association between HTLV-I infection and cancer risk, because the number of cancer deaths was small and the incidence of cancer was not investigated.