Biomedical subjects

K Sadakane

Publications and source records attributed to K Sadakane.

6 recordsLinked to original sources

PubMed2003

Enhancement of acute lung injury related to bacterial endotoxin by components of diesel exhaust particles.

BACKGROUND: Diesel exhaust particles (DEP) synergistically aggravate acute lung injury related to lipopolysaccharide (LPS) in mice, but the components in DEP responsible for this have not been identified. A study was undertaken to examine the effects of the organic chemicals (DEP-OC) and residual carbonaceous nuclei (washed DEP) derived from DEP on LPS related lung injury. METHODS: ICR mice were divided into experimental groups and vehicle, LPS, washed DEP, DEP-OC, washed DEP+LPS, and DEP-OC+LPS were administered intratracheally. The cellular profile of the bronchoalveolar lavage (BAL) fluid, pulmonary oedema, lung histology, and expression of proinflammatory molecules and Toll-like receptors in the lung were evaluated. RESULTS: Both DEP-OC and washed DEP enhanced the infiltration of neutrophils into BAL fluid in the presence of LPS. Washed DEP combined with LPS synergistically exacerbated pulmonary oedema and induced alveolar haemorrhage, which was concomitant with the enhanced lung expression of interleukin-1beta, macrophage inflammatory protein-1alpha, macrophage chemoattractant protein-1, and keratinocyte chemoattractant, whereas DEP-OC combined with LPS did not. Gene expression of Toll-like receptors 2 and 4 was increased by combined treatment with washed DEP and LPS. The enhancement effects of washed DEP on LPS related changes were comparable to those of whole DEP. CONCLUSIONS: These results suggest that the residual carbonaceous nuclei of DEP rather than the extracted organic chemicals predominantly contribute to the aggravation of LPS related lung injury. This may be mediated through the expression of proinflammatory cytokines, chemokines, and Toll-like receptors.

Animals↗

PubMed2001

The spin temperature of NH3 in Comet C/1999S4 (LINEAR).

A high-dispersion spectrum of Comet C/1999S4 (LINEAR) was obtained in the optical region with the high-dispersion spectrograph on the Subaru telescope when the comet was 0.863 astronomical units from the Sun before its disintegration. We obtained high signal-to-noise ratio emission lines of the cometary NH2 bands from which an ortho-to-para ratio (OPR) of 3.33 +/- 0.07 was derived on the basis of a fluorescence excitation model. Assuming that cometary NH2 mainly originates from ammonia through photodissociation, the derived OPR of NH2 molecules should reflect that of ammonia, which provides information on the environment of molecular formation or condensation and of the thermal history of cometary ices. Assuming that the OPR of ammonia in comets was unchanged in the nucleus, the derived spin temperature of ammonia (28 +/- 2 kelvin) suggests that a formation region of the cometary ammonia ice was between the orbit of Saturn and that of Uranus in the solar nebula.

Ammonia↗

PubMed2001

Indexing huge genome sequences for solving various problems.

Because of the increase in the size of genome sequence databases, the importance of indexing the sequences for fast queries grows. Suffix trees and suffix arrays are used for simple queries. However these are not suitable for complicated queries from huge amount of sequences because the indices are stored in disk which has slow access speed. We propose storing the indices in memory in a compressed form. We use the compressed suffix array. It compactly stores the suffix array at the cost of theoretically a small slowdown in access speed. We experimentally show that the overhead of using the compressed suffix array is reasonable in practice. We also propose an approximate string matching algorithm which is suitable for the compressed suffix array. Furthermore, we have constructed the compressed suffix array of the whole human genome. Because its size is about 2G bytes, a workstation can handle the search index for the whole data in main memory, which will accelerate the speed of solving various problems in genome informatics.

Abstracting and Indexing↗

PubMed2000

Direct projection from the cardiovascular control region of the cerebellar cortex, the lateral nodulus-uvula, to the brainstem in rabbits.

In decerebrate unanesthetized rabbits, electrical stimulation of the lateral nodulus-uvula in the cerebellar vermal cortex evoked an increase in renal sympathetic nerve activity, an increase in blood pressure and a decrease in renal arterial blood flow, which were all in contrast to the effects reported previously in the anesthetized rabbits. In order to identify the pathway mediating these responses, we investigated the Purkinje cell projection from the lateral nodulus-uvula using both anterograde (biotinylated dextran amine, BDA) and retrograde (horseradish peroxidase, HRP) tracing methods in rabbits. When BDA was iontophoretically injected into the lateral nodulus-uvula, labeled Purkinje cell axons were found within and around the superior and inferior cerebellar peduncles (SCP and ICP, respectively). Furthermore, terminal-like fields were found in the dentate and vestibular nuclei as reported in previous studies. However, the terminal-like patterns that we observed in the parabrachial nucleus (PB) in the rabbit have not been reported yet. When HRP was microinjected into the lateral PB, retrogradely labeled Purkinje cells were found in the lateral nodulus-uvula. These results indicate that Purkinje cells in the lateral nodulus-uvula project into the vestibular nuclei via the ICP and to the lateral PB via the SCP. We suggest that these two pathways mediating cardiovascular responses have different sensitivities to anesthetics.

Animals↗

PubMed2000

Biological sequence compression algorithms.

Today, more and more DNA sequences are becoming available. The information about DNA sequences are stored in molecular biology databases. The size and importance of these databases will be bigger and bigger in the future, therefore this information must be stored or communicated efficiently. Furthermore, sequence compression can be used to define similarities between biological sequences. The standard compression algorithms such as gzip or compress cannot compress DNA sequences, but only expand them in size. On the other hand, CTW (Context Tree Weighting Method) can compress DNA sequences less than two bits per symbol. These algorithms do not use special structures of biological sequences. Two characteristic structures of DNA sequences are known. One is called palindromes or reverse complements and the other structure is approximate repeats. Several specific algorithms for DNA sequences that use these structures can compress them less than two bits per symbol. In this paper, we improve the CTW so that characteristic structures of DNA sequences are available. Before encoding the next symbol, the algorithm searches an approximate repeat and palindrome using hash and dynamic programming. If there is a palindrome or an approximate repeat with enough length then our algorithm represents it with length and distance. By using this preprocessing, a new program achieves a little higher compression ratio than that of existing DNA-oriented compression algorithms. We also describe new compression algorithm for protein sequences.

Algorithms↗

PubMed1998

Vagal afferent projections to lobule VIIa of the rabbit cerebellar vermis related to cardiovascular control.

In decerebrate rabbits we recorded simultaneously field potentials in lobule VIIa of the vermal cerebellar cortex and the vagal compound action potentials (vCAPs) proximally in the vagus nerve following electrical stimulation distally in the same nerve at different intensities. Four principal components of the vCAP were distinguished based on their peak conduction velocities. Their velocities were component I, 67-100 m/s; II, 28-50 m/s; III, 6-28 m/s, IV, 0.4-1.3 m/s. A collision test based on stimulating the recurrent laryngeal nerve identified component I and sub-component IIa of the vCAP as being due to the motor fibres of the descending limb of the nerve. The field potentials evoked in lobule VIIa by electrical stimulation of the cervical vagus nerve were climbing fibre responses as judged by the characteristics of their lamina profile and their response to high frequency stimulation. These field potentials in lobule VIIa correlated most closely with the component III of the vCAP; particularly with a sub-component IIIa of the vagus. Based on the investigations by Evans and Murray (1954) (Histological and functional studies on the fibre composition of the vagus nerve of the rabbit. J. Anat. (Lond.) 88, 320-337) in the rabbit, and by Paintal (1963) (Vagal afferent fibres. Ergeb. Physiol. 52, 74-156) and Mei (1970) (Cardiovascular and respiratory vagal mechanoreceptors in the cat. Exp. Brain Res. 11, 480-501) in the cat, component III is most likely to be due to receptors from the heart and a part of the pulmonary stretch receptors.

Afferent Pathways↗