PubMed Health⌕ Search

Biomedical subjects

M Hisada

Publications and source records attributed to M Hisada.

At least 37 records · Page 2Linked to original sources
PubMed2000

Cardioactive peptides isolated from the brain of a Japanese octopus, Octopus minor.

Octopus cardioactive peptides (Ocp-1: Gly-D-Phe-Gly-Asp, and Ocp-3: Gly-Ser-Trp-Asp) were isolated from brain extracts of the octopus, Octopus minor, using the isolated systemic heart as a bioassay. These peptides showed both positive chronotropic and inotropic effects on the heart. The stereoisomers at position 2 were also isolated, but their activities were only 1/10(3)-1/10(4) those of the corresponding isomers. The presence of the peptides in the systemic heart was confirmed by time-of-flight mass spectrometry (MS) and tandem MS analysis. The results suggested that Ocp-1 and Ocp-3 might be involved in excitatory control of the octopus cardiovascular system as neuropeptides and/or neurohormones.

Amino Acid Sequence↗
PubMed1999

Gender difference in skin reactivity to purified protein derivative among carriers of HTLV-I in Japan.

The incidence of malignancies due to oncogenic virus infections tends to be higher in men than in women. Gender-related differences in cell-mediated immunity, which plays a role in viral pathogenesis, may explain this observation. To explore this possibility in the context of HTLV-I infection, we examined skin reactivity to purified protein derivative (PPD) among 128 residents of an HTLV-I endemic area in Japan, who were born before 1921 and are assumed to have been exposed to M. tuberculosis bacilli. The odds ratio (OR) for reduced PPD reactivity (erythema <10 mm in diameter) was calculated by multiple logistic regression analysis. Men were significantly less likely than women to have reduced PPD reactivity among HTLV-I-negative individuals (26% versus 59%; p < .01); whereas this gender difference was not apparent among HTLV-I carriers (63% versus 62%; p = .87). HTLV-I positivity was strongly associated with reduced PPD reactivity in men, but not in women (odds ratio [OR], 7.3 versus 1.2; p = .05). Although this observation may be due, in part, to a longer average duration of HTLV-I infection in men compared with women, the finding also raises the possibility that men may be inherently more susceptible to loss of PPD reactivity by HTLV-I infection.

Aged↗
PubMed1999

Establishment of a combined strategy of genetic and mass spectrometric analyses for characterizing hemoglobin mutations. An example of Hb Hoshida (beta43Glu-->Gln).

Structural analysis of mutant hemoglobins has been efficiently accomplished by a consecutive mass spectrometric strategy: molecular mass measurement of the protein to detect mutation and to determine the molecular mass change, and fragmentation analysis with collision-induced dissociation to determine the site and type of mutation. A flaw of this method is an inherent inability to detect a mutation associated with no or little change of the molecular mass. In the present study, the strategy was improved by incorporating genetic analysis prior to mass spectrometry, which confirms the resulting amino acid change and searches for possible post-translational modifications. The method was applied to an unknown mutant, and elucidated a substitution of glutamine for glutamic acid at position 43 of beta-globin subunit, the mutation of Hb Hoshida.

Amino Acid Sequence↗
PubMed1999

Human T-lymphotropic virus type I infection.

Human T-cell lymphotropic virus type I (HTLV-I) is the first human retrovirus to be associated with malignant disease--namely, adult T-cell leukaemia/lymphoma. HTLV-I has also been associated with several non-malignant conditions, notably the chronic neurodegenerative disorder, HTLV-I associated myelopathy (also known as tropical spastic paraparesis), infective dermatitis of children and uveitis. More recent evidence points to disease associations not previously linked to HTLV-I. Thus, the disease spectrum of HTLV-I is not fully known. HTLV-I has a worldwide distribution with major endemic foci in the Caribbean and southern Japan. The public health importance is confirmed by the major routes of transmission, which are mother-to-child, blood transfusion, and sexual activity. Unfortunately, no vaccine is available yet and there is no proven treatment for advanced HTLV-I disease.

Adult↗
PubMed1998

Suppression of skin reactivity to purified protein derivative by hepatitis C virus among HTLV-I carriers in Japan.

In a population endemic for HTLV-I and hepatitis C virus (HCV), HTLV-I infection has been associated with a suppressed cell-mediated immunity measured by anergy to purified protein derivative (PPD). However, the effect of HCV and the impact of coinfection with HTLV-I and HCV have not been previously evaluated. To approach this issue, PPD reactivity was analyzed among 300 study subjects in the community-based Miyazaki Cohort Study. An erythema of <10 mm in diameter 48 hours after subcutaneous injection of the antigen defined PPD anergy. Logistic regression was used to estimate the relative risks. With adjustment for age, gender, and HTLV-I seropositivity, anti-HCV positivity was not independently associated with PPD anergy (odds ratio [OR] = 1.1; 95% confidence interval [CI] = 0.6-1.9). Subjects with both anti-HCV and anti-HTLV-I had a fivefold risk of PPD anergy relative to those free of both infections (OR = 5.2; 95% CI = 1.9-13.8). The risk was nearly threefold among those with anti-HTLV alone (OR = 2.8; 95% CI = 1.4-5.3). Thus, coinfected study subjects were 1.9 times more likely to have PPD anergy compared with those singly infected with HTLV-I (p = .34). HCV infection may slightly increase the risk of PPD anergy among HTLV-I carriers.

Adult↗
PubMed1998

Risk factors for adult T-cell leukemia among carriers of human T-lymphotropic virus type I.

The presence of circulating "flower cells" and a low prevalence of antibody to Tax regulatory protein of human T-lymphotropic virus type I (HTLV-I) are characteristics of adult T-cell leukemia (ATL). To examine the predictability of levels of HTLV-I antibodies and of flower cell-like abnormal lymphocytes (Ably) for the risk of ATL among asymptomatic HTLV-I carriers, we prospectively evaluated the levels of viral markers of five HTLV-I carriers who developed ATL and 38 age-, sex-, and screen-matched HTLV-I-positive controls in the Miyazaki Cohort Study. After accounting for matching factors, Ably level was slightly, but not significantly, higher among cases than among controls (P =.13). Anti-HTLV-I (odds ratio [OR] = 1.6 per twofold dilution; 95% confidence interval [CI] 0.94, 3.8) was associated with ATL diagnosis, but antibody to Tax regulatory protein (anti-Tax) was not (OR = 0.78; 95% CI 0.26, 1.7). Anti-Tax level was low for all ATL cases for up to 10 years preceding their diagnosis, independent of the level of anti-HTLV-I titer. HTLV-I carriers with a higher anti-HTLV-I titer and a lower anti-Tax reactivity may be at greatest risk of ATL.

Adult↗
PubMed1998

Isolation and structure of pompilidotoxins, novel peptide neurotoxins in solitary wasp venoms.

Novel peptide neurotoxins, alpha- and beta-pompilidotoxins (alpha- and beta-PMTXs), were purified from the venoms of the solitary wasps Anoplius samariensis and Batozonellus maculifrons. Their structures were analyzed mostly by MALDI-TOF-MS, which were corroborated by solid-phase synthesis. alpha-PMTX, with 13 amino acid residues and the sequence of Arg-Ile-Lys-Ile-Gly-Leu-Phe-Gln-Asp-Leu-Ser-Lys-Leu-NH2, greatly potentiates synaptic transmission of lobster leg muscle by the presynaptic mechanisms. beta-PMTX, in which the lysine residue at 12 position of alpha-PMTX was replaced with arginine, was more potent than alpha-PMTX.

Animals↗
PubMed1998

Predictors of level of circulating abnormal lymphocytes among human T-lymphotropic virus type I carriers in Japan.

Human T-lymphotropic virus type I (HTLV-I) carriers often have abnormal lymphocytes (Ably) that resemble malignant cells of adult T-cell leukemia (ATL). To identify predictors of the level of Ably in a longitudinal study of asymptomatic HTLV-I carriers, we analyzed data from 215 subjects (67 men and 148 women) with multiple Ably measurements on blood smears. Ably+ (those having Ably > 0.6% of leukocytes counted on a blood smear at least once) was strongly associated with a high proviral load (OR 8.9; 95% CI 4.1, 19.5). The association among those defined as Ably++ (Ably > 0.6% at all screens or Ably > 1.6% at least once) was higher (19.7; 6.9, 56.1). Ably++ was also significantly associated with male gender (2.8; 1.0, 7.8). Multivariate analysis of Ably level indicates that men with a high proviral load, high anti-HTLV-I titer and low anti-Tax reactivity have the highest Ably level.

Carrier State↗
PubMed1998

Multiple primary cancers in families with Li-Fraumeni syndrome.

BACKGROUND: Li-Fraumeni syndrome is a dominantly inherited disorder characterized by early-onset breast cancer, sarcomas, and other cancers in children and young adults. Members of families with this syndrome also develop multiple primary cancers, but the frequency is unknown. To approach this issue, we quantified the incidence of second and third primary cancers in individuals from 24 Li-Fraumeni kindreds originally diagnosed with cancer during the period from 1968 through 1986. METHODS: The relative risk (RR) of subsequent cancers and 95% confidence intervals (CIs) were calculated by use of population-based incidence data from the Connecticut Cancer Registry. Kaplan-Meier analysis was used to determine the cumulative probability (+/- standard error) of subsequent cancers. RESULTS: Among 200 Li-Fraumeni syndrome family members diagnosed with cancer, 30 (15%) developed a second cancer. Eight individuals (4%) had a third cancer, while four (2%) eventually developed a fourth cancer. Overall, the RR of occurrence of a second cancer was 5.3 (95% CI = 2.8-7.8), with a cumulative probability of second cancer occurrence of 57% (+/- 10%) at 30 years after diagnosis of a first cancer. RRs of second cancers occurring in families with this syndrome were 83.0 (95% CI = 36.9-187.6), 9.7 (95% CI = 4.9-19.2), and 1.5 (95% CI = 0.5-4.2) for individuals with a first cancer at ages 0-19 years, 20-44 years, and 45 years or more, respectively. Thirty (71%) of 42 subsequent cancers in this group were component cancers of Li-Fraumeni syndrome. CONCLUSIONS: Compared with the general population, members of Li-Fraumeni syndrome families have an exceptionally high risk of developing multiple primary cancers. The excess risk of additional primary cancers is mainly for cancers that are characteristic of Li-Fraumeni syndrome, with the highest risk observed for survivors of childhood cancers. Cancer survivors in these families should be closely monitored for early manifestations of new cancers.

Adolescent↗
PubMed1998

Structures of spider toxins: hydroxyindole-3-acetylpolyamines and a new generalized structure of type-E compounds obtained from the venom of the Joro spider, Nephila clavata.

Facile structure determination of acylpolyamines, glutamatergic nerve blocker obtained from the venom of the Joro spider (Nephila clavata) was carried out with the use of micro-column LC/MS and high energy collision induced dissociation (CID) mass spectrometry. 6-hydroxyindole-3-acetyl was proposed previously as a putative partial structure, for the acyl moiety of hydroxyindole-type polyamines (NPTX-1 to -6). The NMR data obtained for NPTX-6, NPTX-687 and hydroxyindole-3-acetic acid which was released by acid hydrolysis of Nephila clavata crude venom extracts proved that the lipophilic head is the 4-hydroxyindole-3-acetic acid. Various hydroxyindole-3-acetyl polyamines were found in N. Clavata venom and characterized by mass spectrometry. As a result, type-E, a new class of generalized acylpolyamine structure was proposed in addition to the previously reported polyamine backbones type-A to -D.

Chromatography, Liquid↗
PubMed1997

Alpha-pompilidotoxin (alpha-PMTX), a novel neurotoxin from the venom of a solitary wasp, facilitates transmission in the crustacean neuromuscular synapse.

A new neurotoxin, named alpha-pompilidotoxin (alpha-PMTX) has been found in the venom of the solitary wasp Anoplius safnariensis. In the neuromuscular synapse of the lobster walking leg preparation, alpha-PMTX (10-100 micro/M) caused great enhancement of both the excitatory and inhibitory postsynaptic potentials. Recordings of the excitatory post synaptic currents (EPSCs) at the synaptic sites showed that alpha-PMTX reversibly and dose-dependently potentiates EPSCs. Alpha-PMTX may act primarily on the presynaptic membrane but the mode of action of the toxin is clearly different from other known facilitatory neurotoxins, such as alpha-latrotoxin, apamin or charybdotoxin. This novel toxin will serve as a useful tool in the research field of neuroscience.

Animals↗
PubMed1997

Purification, characterization, and synthesis of three novel toxins from the Chinese scorpion Buthus martensi, which act on K+ channels.

Three novel toxins belonging to the scorpion K+ channel-inhibitor family were purified to homogeneity from the venom of the Chinese scorpion Buthus martensi. They have been identified according to their molecular mass (3800-4300 Da) and their neurotoxicity in mice and characterized as 37-amino acid peptides. One of them shows 81-87% sequence identity with members of the kaliotoxin group (named BmKTX), whereas the other two, named BmTX1 and BmTX2, show 65-70% identity with toxins of the charybdotoxin group. Their chemical synthesis by the Fmoc methodology allowed us to show that BmKTX, unlike BmTX1 and BmTX2, possesses an amidated C-terminal extremity. Toxicity assays in vivo established that they are lethal neurotoxic agents in mice (LD50s of 40-95 ng per mouse). Those toxins proved to be potent inhibitors of the voltage-gated K+ channels, as they were able to compete with [125I]kaliotoxin for its binding to rat brain synaptosomes (IC50s of 0.05-1 nM) and to block the cloned voltage-gated K+ channel Kv1.3 from rat brain, expressed in Xenopus oocytes (IC50s of 0.6-1.6 nM). BmTX1 and BmTX2 were also shown to compete with [125I]charybdotoxin for its binding to the high-conductance Ca2+-activated K+ channels present on bovine aorta sarcolemmal membranes (IC50s of 0.3-0.6 nM). These new sequences show multipoint mutations when compared to the other related scorpion K+ channel toxins and should prove to be useful probes for studying the diverse family of K+ channels.

Amino Acid Sequence↗
PubMed1997

Characterization of four toxins from Buthus martensi scorpion venom, which act on apamin-sensitive Ca2+-activated K+ channels.

Four peptidyl inhibitors of the small-conductance Ca2+-activated K+ channels (SK(Ca)) have been isolated from the venom of the Chinese scorpion Buthus martensi. These peptides were identified by screening C18 HPLC fractions of the crude venom by means of mass analysis by matrix-assisted-laser-desorption/ionization time-of-flight mass spectrometry, and toxicological tests in mice. Edman degradation analysis of the purified peptides showed sequences of 28-31 amino acids including 6 cysteine residues. Three of the sequences were similar to the P01 peptides from Androctonus scorpions, showing 76% sequence similarity for the most closely related, named BmP01, and 46% for the other two, named BmP02 and BmP03. Like the P01 peptides, these molecules showed a low toxic activity in mice after intracerebroventricular injection, and competed (K0.5 > 1 microM) with iodinated apamin for binding to its receptor site from rat brain, which has been proved to be the SK(Ca) channels. The fourth toxin was structurally related to the P05/leiurotoxin I toxin family, with 90% similarity, and was named BmP05. This toxin exhibited a high toxic activity with lethal effects in mice. Due to its small representation in the venom [less than 0.01% (by mass)], its biological properties have been assessed on the synthetic analogue of BmP05, which was assembled on a solid phase by means of Fmoc methodology. The synthetic peptide was physicochemically identical to the natural peptide, as shown by comparison of their molecular masses and amino acid compositions, and by their coelution after coinjection on capillary electrophoresis. These results confirmed the primary structure of BmP05 including an amidated C-terminus. Similarly to natural BmP05, synthetic BmP05 produced toxic and lethal effects after intracerebroventricular injection in mice (LD50 = 37 ng), and was able to compete with iodinated apamin for binding to its receptor in rat brain (K0.5 = 20 pM).

Amino Acid Sequence↗
PubMed1997

Mass spectrometric structure determination of spider toxins: arginine-containing acylpolyamines from venoms of Brazilian garden spider Nephilengys cruentata.

A new strategy to characterize glutaminergic blocker acylpolymines stored in a spider venom with mass spectrometry is described. The crude spider venom extracts are amenable to direct MALDI mass spectrometry analysis which provides a rapid and accurate means of measuring the molecular weights of acylpolyamines without the isolation of individual samples. Compared with the previously developed mu-column HPLC/MS method, this procedure provides more efficient detection and identification of complex venom constituents. Twenty-five acylpolyamines were detected from Brazilian garden spider Nephilengys cruentata crude venom extracts by both HPLC/MS and MALDI-mass spectrometry. These acylpolyamine structures were determined by high-energy collision induced dissociation MS/MS method. Most of the compounds were classified into the previously reported generalized structures types A to D, which were found from the venom of Nephilengys borbonica. The structures of four acylpolyamines (M + H)+, m/z 623, 646, 688, and 745, which were not contained in the venom of Nephilengys borbonicare were determined to have arginine at the polyamine chain terminal and were named NPTX-622, -645, -687, and -744, respectively.

Animals↗
PubMed1997

[Characterization of spider venom by mass spectrometry, construction of analytical system].

Spiders belonging to the genera, Nephila, Nephilengys, Araneus, etc., possess various polyamine toxins in their venom glands which paralyze insects by blocking the nerve-muscle signal transduction of glutaminergic synapses. More than 50 kinds of polyamine toxin analogs have been characterized which consist, in general, of the aromatic or heteroaromatic moiety connected with the combination of various types of polyamine chains. We are developing a new analytical system by means of a modern mass spectrometric technique which satisfies more rapid, highly sensitive and simple clean-up procedure without complicated chromatographic treatment. The trial of such approach has been performed by employing crude spider venom as the model material. This review article concerns with such proceeding of mass spectrometric analysis by microcolumn HPLC hyphenated FAB-MS system, continuous flow FAB-MS/MS system with high energy collision charge-remote fragmentation, solid and liquid matrix assisted laser desorption ionization (MALDI- and liquid MALDI-) technique connected with tandem mass spectrometer performing in the institute and in addition, femto-molar characterization of new spider venom spider polyamine toxins as a result of the application of such new techniques is addressed.

Animals↗
PubMed1994

Descending control of nonspiking local interneurons in the terminal abdominal ganglion of the crayfish.

1. Electrical stimulation of afferents innervating an exopodite causes a closing pattern of activity in the uropod motor neurons. In this reflex two distinct types of nonspiking local interneurons, posterolateral (PL) and anterolateral (AL) types, classified by their gross morphology and somata location, receive sensory inputs and control the motor output to the uropod. 2. In the sensory-motor pathway, the PL and AL nonspiking local interneurons formed opposing and parallel connections with uropod motor neurons. For example, the PL interneurons that excited the closer, reductor motor neuron by injecting depolarizing current received depolarizing postsynaptic potentials (PSPs), whereas the AL interneurons of the same output received hyperpolarizing PSPs. The PL interneurons that inhibited the reductor motor neuron received hyperpolarizing PSPs, whereas the AL interneurons of the similar output received depolarizing PSPs. 3. During fictive abdominal extension, induced by electrical stimulation of extension-evoking command fibers in the second-third abdominal connective, the uropod motor neurons show an opening pattern of activity that is opposite to the pattern elicited by sensory stimulation. Furthermore, sensory stimulation during ongoing fictive abdominal extension has little effect on the uropod motor neurons. 4. Except for the nonspiking local interneurons, the majority of other local circuit neurons, i.e., spiking local interneurons and ascending interneurons, are not driven by the descending inputs during abdominal extension. 5. A comparison of the responses of the nonspiking local interneurons to both sensory and descending inputs reveals that the majority of nonspiking local interneurons receive both inputs, but the sign of response to each is frequently opposite. This study suggests that the degree of excitability of two distinct types of PL and AL nonspiking local interneurons induced by sensory inputs changes depending on whether the crayfish is in a resting posture or is active with full extension of the abdomen. Ongoing abdominal extension in swimming or defensive crayfish would shift the gain of reflex pathways through the PL and AL interneurons, and motor response resulting from sensory inputs would be modulated.

Abdomen↗