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Biomedical subjects

S Iino

Publications and source records attributed to S Iino.

At least 55 records · Page 3Linked to original sources
PubMed1999

Immunohistochemical localization of a novel acidic calmodulin-binding protein, NAP-22, in the rat brain.

NAP-22 is a neuronal tissue-enriched acidic calmodulin-binding protein with a molecular mass of 22,000 and is recovered in the membrane fraction during biochemical fractionation. We observed the distribution pattern of this protein in the rat brain using an immunohistochemical method by light and electron microscopy. NAP-22 immunoreactivity was detected through the whole brain, and the most dense staining was observed in the forebrain including cerebral cortex, hippocampal formation, olfactory bulb, basal ganglia and thalamus. Immunoreactivity was distributed densely at the neuropil, whereas nerve cells and nerve fibres had little or no reaction. In the brain stem, immunonegative large nerve cell bodies were surrounded by immunopositive varicosities. In the cerebellar cortex, mossy fibre terminals and parallel fibres showed immunoreactivity, whereas Purkinje cells did not. Intracellular distribution was observed in the cerebral and cerebellar cortices. NAP-22 immunoreactivity was noted in the axon terminals, dendritic spines and thin nerve fibres. In these structures, reaction products were associated mainly with synaptic vesicles, pre- and postsynaptic membranes and microtubules. This study demonstrates that the immunoreactivity of NAP-22 is distributed widely in the brain, especially in the synapse, and suggests that this protein is involved in synaptic transmission both in the pre- and postsynaptic region.

Animals↗
PubMed1999

Inverse relation of body-surface activation-recovery interval and recovery time to activation time in normal subjects: stronger correlation and more heterogeneous distribution in activation-recovery interval than in recovery time.

The activation-recovery interval (ARI), measured directly from the myocardium, has shown a good correlation with the action potential duration (APD) in experiments. APD has been reported to be inversely related to the activation time (AT). However, no studies have examined the correlation between the body-surface ARI and AT in normal subjects. Fifty normal subjects (25 men and 25 women) were studied to elucidate the relationship between the body-surface ARI and AT. The body-surface AT was defined as the duration between the QRS onset and the minimum dV/dt of the QRS wave, and ARI as the interval between the minimum dV/dt of the QRS wave and the maximum dV/dt of the T wave in each lead of an 87 unipolar lead system. We also measured the recovery time (RT) defined as the duration between the QRS onset and the maximum dV/dt of the T wave. ARI was inversely correlated with AT (r = -0.73). RT was also inversely correlated with AT (r = -0.61), however, RT had a less heterogeneous distribution than ARI (148 ms vs 159 ms). There were no differences between male and female subjects in the relation between ARI and RT or in the body-surface distribution of ARI and RT. These findings suggest that the body-surface ARI may reflect recovery properties over the cardiac surface and that APD may distribute inhomogeneously over the human cardiac surface with a longer RT over an area with a shorter AT. ARI calculated from body-surface ECG may be a useful noninvasive and repeatedly measurable estimate of APD.

Adolescent↗
PubMed1999

Quantitative detection of hepatitis B virus by transcription-mediated amplification and hybridization protection assay.

We have developed a sensitive and quantitative assay using transcription-mediated amplification and hybridization protection assay for the detection of hepatitis B virus (HBV) DNA in serum. The transcription-mediated amplification was carried out in a single tube. The hybridization protection assay was carried out in a microtiter plate with two probes with different specific activities to obtain a broad detection range. As a result, the assay had a detection range of 5 x 10(3) to 5 x 10(8) genome equivalents (GE)/ml and good quantitative accuracy on a logarithmic scale. A moderately sized manual assay run can be completed within 5 h. Measurements of the amounts of HBV DNA in clinical samples by the assay showed the amounts under various disease conditions to be widely distributed (more than 5 logs, from approximately 5 x 10(3) to 5 x 10(8) GE/ml). It was also shown that the amount of HBV DNA in one chronic hepatitis patient varied widely, with a range of more than 5 logs during long-term monitoring. Our assay has the potential to be used to monitor and determine the prognosis of HBV patients and carriers, especially during interferon treatment.

Carcinoma, Hepatocellular↗
PubMed1999

Voltage sensitivity of slow wave frequency in isolated circular muscle strips from guinea pig gastric antrum.

In circular muscle preparations isolated from the guinea pig gastric antrum, regular spontaneous electrical activity (slow waves) was recorded. Under normal conditions (6 mM K+), the frequency and shape of the slow waves were similar to those observed in ordinary stomach smooth muscle preparations. When the resting membrane potential was hyperpolarized and depolarized by changing the extracellular K+ concentration (2-18 mM), the frequency of slow waves decreased and increased, respectively. Application of cromakalim hyperpolarized the cell membrane and reduced the frequency of slow waves in a dose-dependent manner. Cromakalim (3 microM) hyperpolarized the membrane, and slow waves ceased in most preparations. In the presence of cromakalim, subsequent increases in the extracellular K+ concentration restored the frequency of slow waves accompanied by depolarization. Also, glibenclamide completely antagonized this effect of cromakalim. In smooth muscle strips containing both circular and longitudinal muscle layers, such changes in the slow wave frequency were not observed. It was concluded that the maneuver of isolating circular smooth muscle altered the voltage dependence of the slow wave frequency.

Animals↗
PubMed1999

Problems in the treatment of hepatitis C with interferon.

A marked increase in the rate of eradication of hepatitis C virus (HCV) has been achieved by the combination of interferon-alpha2b and ribavirin when compared with interferon-alpha2b alone. However, even with combination therapy, hepatitis persists in more than half of the patients with chronic herpatitis C and progresses to liver cirrhosis and hepatocellular carcinoma with time. What needs to be kept in mind is that, whether by its natural course or by therapy to suppress liver inflammation or by interferon therapy, the rate of development of hepatocellular carcinoma is reduced if ALT is maintained at low levels. Attention should therefore be focused on the development of drugs which enhance the effect of interferon as well as drugs which suppress liver inflammation.

Alanine Transaminase↗
PubMed1999

[TTV hepatitis].

Explore the source record for details and available documents.

DNA Virus Infections↗
PubMed1999

[Distinct genotypes of TTV infection in non A-non C hepatitis].

TTV DNA was tested by polymerase chain reaction with two set primers(NG061/NG063, T801/T935) in patients with nonA-nonC acute and chronic hepatitis. TTV DNA was detected in 75.9-100% by T801/T935, 47.1-48.3% by NG061/NG063 of 46 patients. The nucleotide sequences including 185 bp in the N22 region of 22 TTV DNA isolates from patients with acute and chronic nonA-nonC hepatitis, were classified into various TTV genotypes such as 1a, 1b and non-1. Our results demonstrate that genotype 1b may induce hepatic injury.

Amino Acid Sequence↗
PubMed1998

A new system to detect native microaggregates of platelets in vivo, with a novel platelet aggregometer employing laser light scattering.

Circulating platelets are susceptible to various stimuli in vessels, and a certain portion of platelets may thereby form native microaggregates (NMAs), which can be visualized by a bother scanning electron microscopy (SEM). We developed an easy method to evaluate the existence and extent of NMAs and the subsequent spontaneous platelet aggregation (SPA) induced by not any agonist but stirring force with a novel platelet aggregometer (PA-200; Kowa, Tsukuba, Japan) employing a particle-counting method based on laser light scattering. In this system, platelet-rich plasma obtained by a delicate centrifugation was infused in a cuvette to replace the content and to avoid stirring shear. An insertion attachment was designed in a coaxial shape to maintain a constant sample volume. Our data indicated that NMAs, tentatively defined as a "small" division by their light scattering (25-400 of the intensity threshold), could be detected by not only a complicated SEM but also by our simple system with the PA-200 in a few minutes. No correlation was found in the comparison of the existence of NMAs and the SPA generation, in aliquot platelets, respectively. These results suggested that NMAs and SPA might be mutually different cluster and have meanings as representations of platelet status.

Blood Platelets↗
PubMed1998

Neurocalcin-immunopositive nerve terminals in the muscle spindle, Golgi tendon organ and motor endplate.

The present study revealed the immunohistochemical distribution of neurocalcin, a three EF-hand calcium-binding protein, in the rat muscles and tendons. In the muscle spindles, annulospiral endings, which made spirals around the intrafusal muscles, showed intense neurocalcin-immunoreactivity. In the Golgi tendon organs, immunopositive thick nerve fibers entered the collagenous fibers resulting in the projection of many swelling terminals. In all examined muscles, nerve terminals in the motor endplates showed neurocalcin-immunoreactivity associated with the membranes of synaptic vesicles and mitochondria. These findings suggest that neurocalcin is distributed and regulates calcium signaling in both afferent and efferent nerve terminals in the muscles and tendons.

Animals↗
PubMed1998

Cloning and expression of a cDNA encoding a new neurocalcin isoform (neurocalcin alpha) from bovine brain.

Neurocalcin (NC), a neuron-specific EF-hand Ca2+-binding protein, purified from bovine brain [Terasawa, Nakano, Kobayashi and Hidaka (1992) J. Biol. Chem. 267, 19596-19599] contains multiple isoforms. We previously cloned NCdelta from bovine brain and showed high expression in neuronal tissues [Okazaki, Watanabe, Ando, Hagiwara, Terasawa and Hidaka (1992) Biochem. Biophys. Res. Commun. 185, 147-153]. We report here the molecular cloning and expression of a cDNA encoding bovine brain NCalpha. The translated bovine protein is 191 amino acids long and shares 69.1% of its amino acid sequence with NCdelta. Recombinant NCalpha migrates as a single 23 kDa band and exhibits a Ca2+-dependent mobility shift on SDS/PAGE. Analysis of fluorescence emission spectra showed the Ca2+-induced peak at 337 nm. Interestingly, the mobility shift and the fluorescence intensity at 337 nm were larger for NCalpha than for NCdelta. In Ca2+-overlay experiments, however, the apparent affinity of NCalpha for 45Ca2+ was similar to that of NCdelta. Immunohistochemical analysis revealed NCalpha expression in the granular layer of the rat cerebellar cortex whereas NCdelta was found in the Purkinje cell layer. In the rat olfactory bulb, NCalpha was located in external tufted cells, and NCdelta was found in the periglomerular cells. These data demonstrate that NC isoforms differ in their tissue distribution and conformational changes induced by Ca2+ binding. Thus differential regulation of the two NC isoforms may be involved in control of neuron function.

Amino Acid Sequence↗
PubMed1998

High-Resolution X-ray Diffraction of Muscle Using Undulator Radiation from the Tristan Main Ring at KEK.

High Energy Accelerator Research Organization (KEK), Tsukuba, Japan.High-resolution X-ray diffraction studies on striated muscle fibres were performed using a hard X-ray undulator installed in the Tristan main ring at KEK, Tsukuba, Japan. The performance of the undulator, along with an example experiment which exploited the unique characteristics of undulator radiation, are reported. The vertical divergence angle of the first harmonic of the undulator was approximately 10 micro rad under 8 GeV multi-bunch operating conditions and the peak photon flux density was estimated to be approximately 3 x 10(16) photons s(-1) mrad(-2) (0.1% bandwidth)(-1) (10 mA)(-1). The well collimated X-ray beam from the undulator made it possible to resolve clearly, with high angular resolution ( approximately 700 nm), the closely spaced diffraction peaks on the meridional axis in the X-ray patterns arising from the thick filaments of a striated muscle under static conditions. By fitting the meridional intensity pattern, a model for the molecular arrangement of the constituent proteins in the thick filaments is proposed. These studies of muscle demonstrate the promise of undulator radiation from third-generation sources for high-resolution diffraction studies.

Journal Article↗
PubMed1998

Neurocalcin-immunopositive neurons in the rat sensory ganglia.

Distribution of neurocalcin, a calcium-binding protein having three EF hand motifs, in the rat sensory ganglia was demonstrated immunochemically and immunohistochemically. Immunoblot analysis of trigeminal, nodose and dorsal root ganglia homogenates revealed an immunoreactive band at approximately 24 kDa. Neurons labeled by the neurocalcin-antiserum represent 54%, 41% and 46% cells in the trigeminal, nodose and dorsal root ganglia, respectively. Size distribution of immunopositive cells showed a varying range. Most large cells (more than 80%) showed immunoreactivity in the trigeminal and dorsal root ganglia. A double immunofluorescent study was performed to determine the colocalization with calbindin D28k or parvalbumin, which are both calcium-binding proteins. In the trigeminal and dorsal root ganglia, almost all calbindin- or parvalbumin-immunoreactive neurons showed neurocalcin-immunoreactivity, whereas approximately 30-40% neurocalcin-immunopositive cells had calbindin- or parvalbumin-immunoreactivity. In the nodose ganglia, parvalbumin showed localization similar to other ganglia, but about half the calbindin-immunoreactive neurons had neurocalcin-immunoreactivity. These studies show that neurocalcin-immunopositive neurons are widely distributed in the sensory ganglia and most calbindin- or parvalbumin-immunoreactive neurons also contain neurocalcin. In the sensory neurons, neurocalcin may have a significant role in calcium signaling.

Animals↗
PubMed1998

Relationship between Joint National Committee-VI classification of hypertension and ambulatory blood pressure in patients with hypertension diagnosed by casual blood pressure.

BACKGROUND: White-coat hypertension has been diagnosed arbitrarily based on different criteria. In 1997, the Joint National Committee-VI (JNC-VI) reported a new classification of hypertension and strongly emphasized the importance of ambulatory blood pressure (ABP) monitoring. The report pronounced normal ABP values for the first time. HYPOTHESIS: The study's aim was to clarify the relationship between casual blood pressure (BP) and ABP of patients with essential hypertension in each stage of JNC-VI classification, and the prevalence of white-coat hypertension diagnosed by using JNC-VI normal ABP criteria. METHODS: Ambulatory blood pressure was monitored non-invasively in 232 patients with essential hypertension whose casual BP was > or = 140/90 mmHg. The patients were classified according to JNC-VI classification, and their casual BP was compared with ABP. The criterion of white-coat hypertension was defined as casual BP > or = 140/90 mmHg with normal ABP according to JNC-VI criteria (< 135/85 during daytime and < 120/75 during nighttime). RESULTS: Mean ABP increased as the stage advanced, and the differences between casual BP and ABP also increased. There were considerable overlaps in the distribution of ABP among stages. The prevalence of white-coat hypertension was 13% overall: 30% of the patients with isolated systolic hypertension, 19% of those in stage 1, 10% in stage 2, and 4% in stage 3. CONCLUSIONS: Classification of hypertension based on casual BP may not always correspond in severity to that based on ABP. Ambulatory blood pressure monitoring recommended by JNC-VI is very useful for the evaluation of hypertension to differentiate white-coat hypertension from true hypertension.

Adult↗
PubMed1998

Precore wild-type DNA and immune complexes persist in chronic hepatitis B after seroconversion: no association between genome conversion and seroconversion.

Precore hepatitis B virus (HBV) mutants may gradually prevail during or after seroconversion (SC) from hepatitis B e antigen (HBeAg) to hepatitis B e antigen antibody (anti-HBe) status in many chronic hepatitis B (CH-B) patients. However, patients with CH-B still produce anti-HBe more than several years after SC, and the relationship between SC and genome conversion in the precore region has not been clarified. Therefore, in patients with CH-B who had a sustained loss of HBeAg and complete remission of hepatitis after SC, the precore region was sequenced in paired serum samples from 1 year before SC to 3 years after SC. Mutant precore defective HBV DNA was found in only 6 (19%) of 31 CH-B patients who had a complete remission of hepatitis after SC. Mixed-type HBV DNA (precore wild-type and mutant-type) was found in 4 (13%) patients. Wild-type HBV DNA was found in 21 (68%) CH-B patients after SC. Longer-term follow-up of 11 CH-B patients indicated that 3 of 11 patients experienced precore genome conversion 2 to 3 years after SC. E-plus DNA or e-minus DNA was semiquantitated by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) assays before and after SC. E-plus DNA levels decreased from 10(5.56+/-1.58) to 10(2.45+/-1.61). Similarly, e-minus DNA levels declined from 10(4.25+/-1.56) to 10(1.86+/-1.37). By dot-blot assay, serum HBV DNA became negative soon after SC, as did serum HBeAg. In contrast, HBeAg-containing immune complexes were still detected after SC. Anti-HBe antibody was produced throughout SC and thereafter, as determined by a sensitive experimental assay. Therefore, we conclude that genome-conversion in the precore region is a separate event from HBeAg/anti-HBe seroconversion.

Acute Disease↗