Biomedical subjects

M Kobayashi

Publications and source records attributed to M Kobayashi.

At least 505 records · Page 28Linked to original sources

PubMed2000

Interphase detection of t(4;14)(p16.3;q32.3) by in situ hybridization and FGFR3 overexpression in plasma cell malignancies.

The immunoglobulin (Ig) genes are frequently involved in chromosomal rearrangements with a wide variety of partner loci in multiple myeloma (MM). However, several partner chromosomes have not been detected by conventional cytogenetic methods; for example, 4p16.3 (FGFR3), 6p25.3 (IRF4), and 16q23 (c-maf). To clarify the incidence of t(4;14)(p16.3;q32.3) in primary tumors of MM and to evaluate possible correlations with specific manifestations of the disease, G-banding, double-color fluorescence in situ hybridization (DC-FISH), and/or reverse-transcriptase polymerase chain reaction (RT-PCR) were performed on 40 patients with MM-two with plasmacytoma (PCM) and three with plasma cell leukemia (PCL). All patients were studied by DC-FISH; 40 were studied by G-banding and 36 were studied by RT-PCR. The FISH probes consisted of a cosmid pC385.12 containing the FGFR3 gene, a YAC Y6 containing VH, and a phage Iggamma1-10 containing the gamma1 constant region (Cgamma). We identified eight patients with either FGFR3/Cgamma fusion or FGFR3 overexpression: six patients with both FGFR3/Cgamma fusion and FGFR3 overexpression, one patient with FGFR3/Cgamma, and one with FGFR3 overexpression. FGFR3/Cgamma fusion was demonstrated at a frequency of 19% to 38% on interphase nuclei in seven of the 45 patients. Lytic bone lesions were found to be associated with FGFR3 overexpression. Interphase FISH with FGFR3 and Cgamma probes combined with RT-PCR proved to be an effective tool for detection of this fully cryptic translocation, thus facilitating the characterization of clinical features of MM patients with t(4;14).

Adult↗

PubMed2000

Distinct patterns of cytokine gene suppression by the equivalent effective doses of cyclosporine and tacrolimus in rat heart allografts.

In vitro studies of the mode of action of cyclosporine (CsA) and tacrolimus have indicated that both drugs produce immunosuppression by a quite similar cellular and molecular mechanism to block T cell receptor emanated transcriptional activation of interleukin(IL)-2 and other cytokine genes. Herein, we show that there are distinct patterns of cytokine gene expression in rat heart allografts under equivalent effective doses ("optimal dose") of CsA and tacrolimus. The optimal doses of CsA (10 mg/kg/day) and tacrolimus (3.2 mg/kg/day), which induce similar mean graft survival time (MST), were administered in LEW recipients with ACI heart grafts from day 0 after grafting until sacrifice. Heart grafts were harvested at days 3, 5, and 7. The expression of various cell surface markers, cytokines, and cytotoxic factors was determined by immunohistology and reverse transcriptase-polymerase chain reaction (RFT-PCR). Cell populations that stained positively in the heart tissues of allograft control increased through day 7 for CD4+ and CD8+ T lymphocytes, NKR-Pla+ natural killer (NK) cells, and ED2+ macrophages. CsA and tacrolimus have comparable activity to block these cell local infiltrations. The mRNA levels of the majority of the factors were dramatically up-regulated in the allografts over time, peaking at day 5. The optimal doses of CsA and tacrolimus had similar inhibitory effects on Th1 type cytokine IL-2 and interferon [INF]-gamma), inflammatory cytokine (IL-1beta and tumor necrosis factor [TNF]-alpha), and cytotoxic factor (granzyme B and perforin) mRNA expression. However, the drugs had different effect on Th2 type cytokines (IL-4 and IL-10). Whereas IL-4 expression was not affected by tacrolimus and was enhanced by CsA, IL-10 expression was more significantly suppressed by tacrolimus than CsA. Differences in the suppression of Th2 type cytokine gene expression indicate that the in vivo molecular networks by which CsA and tacrolimus exert their full immunosuppressive activity are not necessarily the same.

Animals↗

PubMed2000

Diffusion-weighted imaging demonstrates transient cytotoxic edema involving the corpus callosum in a patient with diffuse brain injury.

Reversible T2 hyperintense signal abnormality in the corpus callosum, although frequently seen after diffuse brain injury, has not been well clarified. With some accumulated evidence, we report a case of diffuse brain injury in a 24-year-old man. Magnetic resonance imaging (MRI) demonstrated T2 hyperintense signals in the trunk and the splenium of the corpus callosum 12 days postinjury. Echo-planar diffusion-weighted imaging was also performed on the same day, which revealed decreased diffusion (hyperintense signals) in the same site and almost the same size as T2 hyperintense signals. T1-weighted images were normal. Neuropsychological examination of the patient did not show callosal syndrome, namely hemialexia, unilateral agraphia and unilateral apraxia. Repeat MRI on day 20 demonstrated a signal decrease of both T2-weighted images and diffusion-weighted images (DWI) in the lesion. Follow-up MRI at 6 months showed complete resolution of the T2 signal abnormalities and of the corresponding decreased diffusion. Considering that diffusion-weighted imaging showed transient decreased diffusion, the lesion in the corpus callosum indicated the existence of cytotoxic edema. Also, transient DWI hyperintensity, namely cytotoxic edema, in the trunk and the splenium of the corpus callosum does not necessarily reveal callosal deficits.

Adult↗

PubMed2000

Infantile convulsions with mild gastroenteritis.

The development of sensitive new molecular genetic techniques has led to the detection of rotavirus in cerebrospinal fluid, stools and throat swabs from patients with gastroenteritis with accompanying clinical symptoms similar to infantile benign convulsions. Small round structured virus (SRSV) has also been found in stools of patients with similar clinical symptoms by a new procedure. However, the mechanism by which these viral infections induce benign convulsions remains to be elucidated. The present paper reviews recent virological and clinical studies of seizures probably caused by gastroenteritis viruses including rotavirus, SRSV and other viruses.

Caliciviridae Infections↗

PubMed2000

Unique astrocytic inclusion in a 2 month-old baby showing Leigh-like brain lesions with lactic acidosis.

An unique cytoplasmic inclusion was found in astrocytes of a 2-month-old female baby who showed Leigh-like brain lesions with lactic acidosis, hypoglycemia and hepatomegaly. Although a defective enzyme was not determined, a metabolic disorder was suggested from clinicopathological observations. Symmetrically distributed lesions consisting of marked gliosis and proliferation of capillaries were observed in the basal ganglia, thalami and tegmentum. The astrocytic cytoplasmic inclusion was exclusively found in the cerebral and cerebellar white matter, where myelination was immature. The inclusion was round and eosinophilic, and positive for glial fibrillary acidic protein, vimentin, alphaB-crystallin, S-100 protein and microtubule associated protein 1B, immunohistochemically. An electron microscopic examination revealed an accumulation of intermediate filaments, ribosome and rough endoplasmic reticulum in the inclusion. The characteristic of this inclusion is different from that of other reported inclusions. The inclusion showed positive immunoreaction against CuZn superoxide dismutase, catalase, advanced glycation end-product and 4-hydroxy-2-nonenal antibodies, which suggest that oxidative stress is involved in the genesis of the inclusion.

Acidosis, Lactic↗

PubMed2000

Expression of three zebrafish Six4 genes in the cranial sensory placodes and the developing somites.

The homeobox gene Six4/AREC3 is a member of the vertebrate Six family of transcription factor genes. In this study we describe the cloning and expression of three zebrafish homologues of Six4/AREC3, six4.1, six4.2 and six4.3. These zebrafish Six4 proteins show high homology to the mammalian Six4/AREC3 proteins in the most C-terminal region in addition to the Six domain and homeodomain. Whole-mount in situ hybridization showed that six4.1 is expressed in the presumptive cranial placodal precursor cells, and later in the olfactory, otic and lateral line placodes. six4.2 is expressed in the presomitic mesoderm, somites and pectoral fin bud. six4.3 appears to be a unique member of the Six4 proteins and is expressed ubiquitously at gastrulation and later in the tectum.

Amino Acid Sequence↗

PubMed2000

Participation of the conjugated diene part for potent cytotoxicity of callystatin A, a spongean polyketide.

5-epi, 10-epi, 8-Deethyl, and 10-demethyl analogues of callystatin A, a potent cytotoxic spongean polyketide, were synthesized to elucidate structure-requirement for cytotoxic potency. Inversion of the asymmetric center at C-10 in callystatin A minimally affected the activity, while lack of the 10-methyl group in callystatin A decreased cytotoxicity. In addition, the C-5 epimer and the 8-deethyl analogue of callystatin A showed weaker cytotoxicity.

Animals↗

PubMed2000

Chiral recognition in association between antimony potassium tartrate and bis(L-alaninate)ethylenediamine cobalt(III) complexes using electrospray ionization mass spectrometry

The chiral recognition of metal complexes by a quick and sensitive mass spectrometric analysis was investigated. The principle is introduction of an external chiral standard compound and detection of the differential association with two optical isomers. Using electrospray ionization mass spectrometry we detected weak intermolecular association between the external chiral anion bis(mu-L-, D-tartrato)-diantimonate(III), [Sb2(L-, D-tart)2]2- and isomeric bis(L-alaninate) ethylenediamine cobalt(III) complex ions, [Co(L-ala)2(en)]+ in acetonitrile/water solution. The difference in the association with optical isomers of the Co complex was measured. The results were interpreted based on a model of intermolecular interaction involving hydrogen bonding. The prospects of the mass spectrometry method for chiral recognition using the external chiral negative ion [Sb2(L-, D-tart)2]2- was discussed.

Journal Article↗

PubMed2000

Lincomycin-induced endotoxin release in Escherichia coli sepsis: evidence for release in vitro and in vivo.

OBJECTIVE: To evaluate the propensity of lincomycin and clindamycin to induce release of endotoxin, the authors investigated endotoxin release in Escherichia coli isolated from a patient who developed septic shock following lincomycin treatment. METHODS: Endotoxin release from the E. coli isolate exposed to lincomycin, clindamycin, and ceftazidime were determined in vitro and in vivo. RESULTS: In vitro, this E. coli released significantly larger amounts of endotoxin after exposure for 6 hours to lincomycin or clindamycin versus no antibiotic; however, endotoxin release with these antibiotics was significantly less than with ceftazidime. There was no significant difference in in vitro endotoxin release between small (8 mg/L) and large (0.5 minimum inhibitory concentration [MIC]) doses of these antibiotics, and 0.5 MICs of lincomycin and clindamycin were 1024 and 256 mg/L, respectively. These results were supported by scanning electron microscopic observations, which demonstrated that lincomycin, clindamycin, and ceftazidime induced formation of filamentous cells. In addition, plasma endotoxin concentrations after treatment for 4 hours with lincomycin, clindamycin, and ceftazidime (5 mg/kg) were at least 20-fold higher than with no antibiotic in an E. coli sepsis rat model. CONCLUSION: Results of this study suggest that the bacteriostatic antibiotics, lincomycin and clindamycin, induce endotoxin release in the treatment of E. coli infections.

Animals↗

PubMed2000

Nitrile hydrolases.

A number of nitrile-related enzymes have been screened over the past year for use in synthetic applications. There have also been significant advances in our understanding of the structures and modes of regulation of metal-containing nitrile hydratases. Enzyme structural characterization has provided new insights into how the molecular structure determines the enzyme function and how an enzyme can be endowed with new properties. This information has important implications for potential future applications other than the present industrial production of acrylamide and nicotinamide.

Aminohydrolases↗

PubMed2000

Potent in vivo antimalarial activity of 3,15-di-O-acetylbruceolide against Plasmodium berghei infection in mice.

The antimalarial activity of the O-acylated bruceolide derivative, 3,15-di-O-acetylbruceolide, was evaluated against Plasmodium berghei in vivo. The concentration of 3,15-di-O-acetylbruceolide required for 50% suppression (ED50) of P. berghei in mice was 0.46 +/- 0.06 mg/kg/day, whereas bruceolide was only half as effective as 3,15-di-O-acetylbruceolide. Two antimalarial drugs used clinically, chloroquine and artemisinin, demonstrated only low activity corresponding to 1/4 and 1/12 of the ED50 value of 3,15-di-O-acetylbruceolide, respectively. These results may be helpful in the design of better chemotherapeutic bruceolides against falciparum malaria.

Animals↗

PubMed2000

Distinction between chronic hepatitis and liver cirrhosis in patients with hepatitis C virus infection. Practical discriminant function using common laboratory data.

In order to distinguish patients with cirrhosis from those with chronic hepatitis, multivariate discriminant analysis was performed using common laboratory data. A total of 205 consecutive patients were diagnosed by peritoneoscopy and biopsy as having chronic liver disease caused by hepatitis C virus (HCV), 168 with chronic hepatitis and 37 with cirrhosis. Twenty variables and their natural logarithmic transformation were employed in the multivariate analysis. After stepwise variable selection, the following function was finally obtained to discriminate the disease severity, z=0.120xgamma-globulin (%)+0.423xln (hyaluronate) (µg l(-1))-0.059xplatelet (x10(4) counts per mm(3))-0.364xsex (male, 1; female, 2)-3.953. Since the function contained an expression of logarithm and was slightly troublesome to apply, we prepared another discriminant function composed of usual figures without logarithmic transformation, z=0.124x(gamma-globulin (%))+0.001x(hyaluronate) (µg l(-1))-0.075x(platelet (x10(4) counts per mm(3)))-0.413xgender (male, 1; female, 2)-2.005. When a positive result is calculated in the latter equation, the diagnosis of the liver disease indicates cirrhosis, and negative result chronic hepatitis. Accuracy of the two discriminant functions was 90.3 and 91.2%, respectively. A concise linear discriminant function could successfully differentiate liver cirrhosis from chronic hepatitis with an accuracy of 91.2%.

Journal Article↗

PubMed2000

Effective onion vinegar production by a two-step fermentation system.

A two-step fermentation system combining a repeated batch process using a flocculating yeast with a charcoal pellet bioreactor was developed for onion vinegar production. Juice from the red onion R-3, which contained 67.3 g/l total sugar, was smoothly converted to onion alcohol containing 30.6 g/l ethanol by repeated batch operation using the flocculating yeast Saccharomyces cerevisiae strain IR-2. Stable operation was possible and the maximum productivity was about 8.0 g/l/h. A packed bed bioreactor containing charcoal pellets produced from waste mushroom medium was then applied to continuous onion vinegar production from the onion alcohol. Onion vinegar was successfully produced, with a maximum productivity and acetic acid concentration of about 3.3 g/l/h and 37.9 g/l, respectively. The total acetic acid yield calculated from the amount of sugar consumed was 0.86. The two-step system was operated for 50 d and proved to be competitive with other systems in terms of its high productivity, high acetic acid yield, operational stability and low production costs.

Journal Article↗

PubMed2000

Continuous acetic acid production by a packed bed bioreactor employing charcoal pellets derived from waste mushroom medium.

A packed bed bioreactor using charcoal pellets produced from waste mushroom medium by thermal carbonization was developed and applied to continuous acetic acid production. The pellets were characterized by their high specific surface area (200 m2/g) with numerous micropores (2-10 microm). The continuous acetic acid fermentation started up smoothly after seeding and was successfully operated for about 180 d under various retention times. The maximum acetic acid productivity was about 3.9 g/l/h using normal aeration and 6.5 g/l/h using air enriched with 40% O2. The pellets are expected to prove useful as a new packing material for bioreactor in terms of their bacterial affinity, high specific surface area with appropriate pore sizes for bacteria, as well as the operational stability of the system and the low production cost.

Journal Article↗

PubMed2000

Indolyl carboxylic acids by condensation of indoles with alpha-keto acids.

The novel indole derivatives 2,2-bis(3,3'-indolyl)propionic acid (1); 1,1,1,-tris(3,3',3"-indolyl)ethane (2); and 2,2-bis(3, 3'-indolyl)isocaproic acid (3) were isolated from solvent extracts of indole-supplemented supernatants of Escherichia coli and corynebacteria. The compounds were also obtained by chemical synthesis: compounds 1 and 2 from indole and pyruvic acid and compound 3 from indole and alpha-ketoisocaproic acid, following incubation at 37 degrees C in aqueous medium. Tryptophan and pyruvic acid gave the novel 2-(2-tryptophanyl)lactic acid (4). The condensation reaction between indoles and alpha-keto acids was of general nature, and the mild reaction conditions suggested it may proceed in vivo. Examples for endogenous occurrence may be the neuro-degenerative diseases phenylketonuria and maple syrup urine disease, both characterized by elevated blood levels of alpha-keto acids.

Brevibacterium↗

PubMed2000

The primary electron acceptor of green sulfur bacteria, bacteriochlorophyll 663, is chlorophyll a esterified with Delta2,6-phytadienol.

The primary electron acceptor of green sulfur bacteria, bacteriochlorophyll (BChl) 663, was isolated at high purity by an improved purification procedure from a crude reaction center complex, and the molecular structure was determined by fast atom bombardment mass spectroscopy (FAB-mass), (1)H- and (13)C-NMR spectrometry, double quantum filtered correlation spectroscopy (DQF-COSY), heteronuclear multiple-quantum coherence (HMQC) and heteronuclear multiple-bond correlation (HMBC) spectral measurements. BChl 663 was 2.0 mass units smaller than plant Chl a. The NMR spectra showed that the macrocycle was identical to that of Chl a. In the esterifying alcohol, a singlet P7(1) signal was observed at the high-field side of the singlet P3(1) signal in BChl 663, while a doublet peak of P7(1) overlapped that of P11(1) in Chl a. A signal of P7-proton, seen in Chl a, was lacking, and the P6-proton appeared as a triplet signal near the triplet P2-proton signal in BChl 663. These results indicate the presence in BChl 663 of a C=C double bond between P6 and P7 in addition to that between P2 and P3. The structure of BChl 663 was hence concluded to be Chl a esterified with 2,6-phytadienol instead of phytol. In addition to BChl 663, two molecules of the 13(2)-epimer of BChl a, BChl a', were found to be present per reaction center, which may constitute the primary electron donor.

Journal Article↗

PubMed2000

Identification of novel residues involved in nuclear localization of a baculovirus polyhedrin protein.

A baculovirus polyhedrin protein has proven to possess a nuclear localization signal (NLS) sequence and a domain required for supramolecular assembly. Here we investigated five Bombyx mori nucleopolyhedrovirus (BmNPV) mutants that did not produce polyhedra. Two of five mutants were generated during routine baculoviral expression vector screening, and three were isolated by treatment with the mutagen 5-bromo-2'-deoxyuridine (BrdU). Marker rescue mapping and nucleotide sequence analysis showed that mutations in the polyhedrin gene caused the altered phenotype of these mutants. Biochemical fractionation indicated that cells infected with these mutants exhibited polyhedrin protein in both the nucleus and the cytoplasm. Electron microscopic observation revealed that polyhedrin produced by these mutants ocurred in both the nucleus and the cytoplasm, but did not form a crystalline lattice. Despite the incompleteness of polyhedrin nuclear localization, the NLSs of the five mutants were unchanged, although some of the mutations occurred within residues just outside of the domain reported to be required for polyhedron assembly (4). This result suggests that (a) the polyhedrin NLS directs polyhedrin to the nucleus, but the efficiency of this localization is regulated by regions other than the NLS (probably, polyhedrin conformation and its association with the nucleus are also involved), and (b) formation of a crystalline lattice may also be determined by several domains within polyhedrin.

Animals↗

PubMed2000

Induction of apoptosis in human cancer cells by TZT-1027, an antimicrotubule agent.

TZT-1027, a newly synthesized dolastatin 10 derivative, is a potent antitumor agent which inhibits microtubule polymerization and perturbs microtubule dynamics. In this report, we investigated whether TZT-1027 inhibited the growth of various human cancer cells, and the cell death caused by TZT-1027 was due to apoptosis. In addition, we elucidated the apoptosis machinery induced by treatment with TZT-1027. The 50% growth-inhibitory concentrations (IC50 values) of TZT-1027 on cancer cells derived from various sources were not more than 5.9 ng/ml. TZT-1027 showed superior cytotoxicity than any other antitumor agents. Next, we evaluated morphological nuclear change, namely, chromatin condensation and DNA fragmentation. We used three cancer cell lines derived from different types in view of having apoptosis related protein, human leukemia HL-60 (in the presence of both Caspase-3 and Bcl-2), human breast cancer MCF-7 (in the absence of Caspase-3), and human prostate cancer DU145 (in the absence of Bcl-2). TZT-1027 induced DNA fragmentation in the presence but not absence of Caspase-3. Nevertheless, apoptic chromatin condensation was observed in all cancer cells even if there was no Caspase-3. Furthermore, we examined whether TZT-1027, microtubule-disrupting agent, influenced cell cycle progression. Flow cytometric analysis revealed the cells treated with TZT-1027, and with the other antimicrotubule agents, to be arrested at the G2/M phase and subsequently to show fragmented DNA smaller than that of G1 phase cells. Moreover, we tested TZT-1027 for its ability to induce Bcl-2 phosphorylation in human cancer cell lines. TZT-1027 and other agents which interacted with microtubules induced Bcl-2 phosphorylation, whereas DNA-damaging agents did not. The present results suggested an association of the growth-inhibitory effect of TZT-1027 with the induction of apoptosis and indicated that the apoptosis induced by TZT-1027 was followed by G2/M arrest even if there was no Caspase-3 or Bcl-2.

Antineoplastic Agents↗