Biomedical subjects

T Kudo

Publications and source records attributed to T Kudo.

At least 55 records · Page 3Linked to original sources

PubMed2001

Diversification of the microtubule system in the early stage of eukaryote evolution: elongation factor 1 alpha and alpha-tubulin protein phylogeny of termite symbiotic oxymonad and hypermastigote protists.

The symbiotic protists of the lower termite have been regarded as a model of early-branched eukaryotes because of their simple cellular systems and morphological features. However, cultivation of these symbiotic protists is very difficult. For this reason, these interesting protists have not been well characterized in terms of their molecular biology. In research on these organisms which have not yet been cultivated, we developed a method for retrieving specific genes from a small number of cells, through micromanipulation without axenic cultivation, and we obtained EF-1 alpha and alpha-tubulin genes from members of the Hypermastigida--the parabasalid protist Trichonympha agilis and the oxymonad protists Pyrsonympha grandis and Dinenympha exilis--from the termite Reticulitermes speratus gut community. Results of phylogenetic analysis of the amino acid sequences of both proteins, EF-1 alpha and alpha-tubulin, indicate that the hypermastigid, parabasalid, and oxymonad protists do not share a close common ancestor. In addition, although the EF-1 alpha phylogeny indicates that these two groups of protists branched at an early stage of eukaryotic evolution, the alpha-tubulin phylogeny indicates that these protists can be assigned to two diversified clades. As shown in a recent investigation of alpha-tubulin phylogeny, eukaryotic organisms can be divided into three classes: an animal--parabasalids clade, a plant--protists clade, and the diplomonads. In this study, we show that parabasalids, including hypermastigids, can be classified as belonging to the animal--parabasalids clade and the early-branching eukaryote oxymonads can be classified as belonging to the plant--protists clade. Our findings suggest that these protists have a cellular microtubule system that has diverged considerably, and it seems that such divergence of the microtubule system occurred in the earliest stage of eukaryotic evolution.

Animals↗

PubMed2001

Mutated SEA-D227A-conjugated antibodies greatly enhance antitumor activity against MUC1-expressing bile duct carcinoma.

For the purpose of establishing a new adoptive immunotherapy for bile duct carcinoma (BDC), we have directed our attention to superantigens (SAgs), the most potent known activators of T lymphocytes. In our previous study, staphylococcal enterotoxin A (SEA) was conjugated chemically with MUSE11 mAb, which recognizes the MUC1 cancer-associated antigen, and shown to enhance the specific cytotoxic activity of T-LAK cells against MUC1-expressing BDC cells (TFK-1) in vitro and in vivo. However, it is probable that SEA might cause side-effects because of nonspecific binding to class II positive cells. In order to overcome these, we generated mutated SEA (mSEA) by changing Asp at position 227 of native SEA to Ala, which has reduced affinity to MHC class II molecules, but retains the potential for T cell activation. When mSEA-D227A was administered to rabbits to examine effects on blood pressure, 500 times more mSEA-D227A was tolerated than native SEA. This prompted us to construct a mSEA-D227A-conjugated mAb, reactive with MUC1. It augmented the antitumor activity of T-LAK cells significantly, and furthermore, mSEA-D227A could be conjugated to two bispecific antibodies, BsAb (anti-MUC1 x anti-CD3) and BsAb (anti-MUC1 x anti-CD28), which in combination had greater enhancing effects than mSEA-D227A-conjugated anti-MUC1 mAb, and combination of unconjugated BsAbs. These findings indicate a utility of mSEA-D227A-conjugated antibodies for targeted cancer immunotherapy.

Amino Acid Substitution↗

PubMed2001

Cytocidal effect and DNA damage of nedaplatin: a mathematical model and analysis of experimental data.

PURPOSE: Cell cycle non-specific anticancer agents such as cis-diamminedichloroplatinum(II) are believed to depend linearly on the value of the area under the drug concentration time curve, which is supported by a mathematical model. However, the quantitative non-linear phenomena of both the cytocidal effect and DNA crosslink formation by cisdiammine(glycolato)platinum (nedaplatin) have been shown in vitro. Therefore, we developed a new mathematical model to explain these phenomena. METHODS: We assumed that nedaplatin enters intracellular fluid from medium through simple diffusion to form DNA crosslinks that kill cells. We developed a mathematical model to represent this assumption using differential equations that we then solved using an original computer program. The calculated results were compared with the experimental data. RESULTS: The drug's simple diffusion rate constant, the DNA crosslink formation rate constant, and the crosslink-dependent cell death rate constant in the model were 1.8 x 10(-14) (l h-1), 1.6 x 10(8) (l mol-1/2 h-1), 5.45 x 10(1) (mol-1), respectively. The model fits the experimental results statistically. The model also demonstrated theoretical proof that continuous exposure at a low dose was superior to the short exposure at a high dose seen in published experimental data. CONCLUSIONS: We developed a mathematical model to describe the non-linear pharmacodynamic effect of nedaplatin in vitro. This model may provide a novel drug infusion procedure for cancer patients.

Antineoplastic Agents↗

PubMed2001

Cytocidal effect and DNA damage of nedaplatin in vitro by simulating pharmacokinetic parameters.

PURPOSE: The pharmacodynamic effects of cis-diammine(glycolato)platinum (nedaplatin, 254-S) in vitro have been reported, but the dosage and exposure time in vitro have not always been based on clinical observations of the drug's actions in vivo. Regardless of the actual exposure conditions used, the effect of cell-cycle nonspecific anticancer agents such as nedaplatin is believed to depend on the area under the drug concentration-time curve (AUC). In this study, we evaluated the pharmacodynamics of nedaplatin in vitro, especially in relation to its AUC dependency, in terms of cell survival and DNA crosslinking. METHODS: BG-1 human ovarian cancer cells were treated with various concentrations of nedaplatin to simulate the pharmacokinetics of administration in a clinical setting. The BG-1 cells were exposed to nedaplatin dissolved in medium containing serum using constant concentration conditions, either high (maximum 7.69 mg/l) or low (average 1.33 mg/l). These concentrations were based on doses used in clinical studies. We then adjusted the exposure conditions in vitro to simulate the elimination of the drug from serum in vivo as follows: T1/2 alpha 1.20 h and T1/2 beta 2.70 h. The AUC values were set at 4, 8, 16, 25 and 40 mg.h/l for all exposure conditions. A colony-formation assay for the surviving fraction and an alkaline-elution assay for DNA crosslink measurement were done for the pharmacodynamic evaluation with comparison on the basis of the AUC value. RESULTS: Exposure to a low concentration for a long time was the most effective of the exposure conditions at the same AUC value. The greater the AUC value, the higher the crosslink index under all exposure conditions. This index tended to increase particularly after exposure to the low concentration. The natural logarithm of the surviving fraction (Y') was a linear function of the crosslink index regardless of the drug-exposure condition: ln(Y') = -87.2x + ln(5.79), R2 = 0.89. The threshold cytocidal effect was associated with a crosslink index of 0.02. CONCLUSION: There was a strong correlation between the cytocidal effect of nedaplatin and DNA crosslink formation. The cytocidal effect and DNA crosslinking in vitro depended on the exposure conditions used to define the AUC. Therefore, a new pharmacokinetic-pharmacodynamic model for nedaplatin must be constructed to investigate the most effective administration procedure in vivo.

Antineoplastic Agents↗

PubMed2001

Evaluation of long-term sequential changes in bone mass and strength following withdrawal of incadronate disodium (YM175) in ovariectomized rats.

We evaluated the long-term effects of withdrawal of a newer third-generation bisphosphonate, incadronate disodium (YM175), on both cancellous and cortical bone mass and strength in ovariectomized (OVX) rats. One hundred and sixty female SD rats at 13 weeks of age were randomized into four groups: sham-operated, OVX, and low- and high- YM (0.01 or 0.1 mg/kg s.c., three times a week after OVX). After 4 weeks of treatment with vehicle or incadronate disodium, rats from each group (n = 8) were killed at 0 (baseline), 3, 6, 9, and 12 months after the withdrawal of YM175. Histomorphometric studies of the proximal tibia revealed a dose-dependent decrease in OVX-induced bone turnover; cancellous bone volume was significantly higher in the YM groups compared with the OVX control group up to 6 months after withdrawal at low dose and up to 12 months after withdrawal at high dose. The low-dose group showed little effect on tibial diaphyseal cortical bone volume and width, while the high-dose group preserved both cortical parameters 12 months after withdrawal. Mechanical testing of femurs revealed that both metaphyseal and diaphyseal strengths were significantly higher at high dose compared with the OVX group until 12 months after withdrawal. These observations demonstrated that high-dose incadronate disodium preserved both cancellous and cortical bone mass and strength in OVX rats for 12 months after withdrawal of the agent.

Animals↗

PubMed2001

Chromosomal localization, structure, single-nucleotide polymorphisms, and expression of the human H-protein gene of the glycine cleavage system (GCSH), a candidate gene for nonketotic hyperglycinemia.

Nonketotic hyperglycinemia (NKH) is an inborn error of metabolism caused by deficiency in the glycine cleavage system (GCS); this system consists of four individual constituents, P-, T-, H-, and L-proteins. Several mutations have been identified in P- and T-protein genes, but not in the H-protein gene (GCSH), despite the presence of case reports of H-protein deficiency. To facilitate the mutational and functional analyses of GCSH, we isolated and characterized a human p1-derived artificial chromosome (PAC) clone encoding GCSH. GCSH spanned 13.5kb and consisted of five exons. Using the PAC clone as a probe, we mapped GCSH to chromosome 16q24 by fluorescence in situ hybridization. The transcription initiation site was determined by the oligonucleotide-cap method, and potential binding sites for several transcriptional factors were found in the 5' upstream region. Direct sequencing analysis revealed five single-nucleotide polymorphisms. The expression profiles of P-, T-, and H-protein mRNAs were studied by dot-blot analysis, using total RNA from various human tissues. GCSH was expressed in all 29 tissues examined, while T-protein mRNA was detected in 27 of the 29 tissues. In contrast, the P-protein gene was expressed in a limited number of tissues, such as liver, kidney, brain, pituitary gland, and thyroid gland, suggesting distinct transcriptional regulation of each GCS constituent.

Alleles↗

PubMed2001

Immunohistochemical detection of skin-homing T cells expressing fucosyltransferase VII (Fuc-TVII) in vitro and in situ.

Although expression of cutaneous lymphocyte-associated antigen (CLA) is thought to be a specific marker of skin "homing" T cells, it has become clear that CLA is a good marker for high levels of fucosyltransferase VII (Fuc-TVII) activity but does not necessarily represent the epitope required for binding to E-selectin (Wagers et al, 1996, 1997). Therefore, expression of Fuc-TVII is an attractive candidate for identifying skin "homing" T cells. However, analyses of Fuc-TVII expression in human T cells have been performed only at the mRNA level (Nakayama et al, 2000) because of the lack of mAB: In this study Fuc-TVII was for the first time visualized in individual cells by using a novel mAb that we developed. Double immunofluorescence and immunohistochemistry demonstrated the coexpression of Fuc-TVII and CLA in cell lines in which Fuc-TVII mRNA was shown to be expressed at high levels: whereas CLA expression was seen in the cell membrane, Fuc-TVII was identified in a supra- or perinuclear location. Cytoplasmic Fuc-TVII expression was also detectable in both CD4(+) and CD8(+) T cells purified from peripheral blood. Fuc-TVII was also expressed at high levels in many CLA(+) T cells infiltrating the skin. In these peripheral T cells, unlike in cell lines, cytoplasmic expression of Fuc-TVII was not always associated with surface CLA expression. This mAb would serve as a valuable tool for selectively identifying a novel subset of skin "homing" T cells that are not detected by the conventional method because of the lack of CLA expression.

Antibodies, Monoclonal↗

PubMed2001

Orexin A and B evoke noradrenaline release from rat cerebrocortical slices.

1. Orexin A and B, recently identified in the rat hypothalamus are endogenous neuropeptide agonists for the G-protein coupled orexin-1 (OX1) and orexin-2 (OX2) receptors. 2. In the present study, we have examined the effects of orexin A, B and raised extracellular K(+) on noradrenaline release from the rat cerebrocortical slice. We have compared this with other sleep-wake-related (excitatory) neurotransmitters; dopamine, glutamate, serotonin and histamine. 3. Neurotransmitter release studies were performed in rat cerebrocortical slices incubated in modified Krebs buffer (with and without Ca(2+)+EGTA 1 mM) with various concentrations of orexin A, B and K(+) for various times. 4. Orexin A and B-evoked (10(-7) M) noradrenaline release was time-dependent reaching a maximum some 10 min after stimulation. K(+) (40 mM) evoked release was also time dependent but reached a maximum after 6 min. Orexin A, B and K(+) stimulation of release was concentration dependent with pEC(50) and E(max) (% of basal) values of 8.74+/-0.32 (1.8 nM) and 263+/-14% and 8.61+/-0.38 (2.4 nM) and 173+/-7% and 1.43+/-0.02 (37 mM) and 1430+/-70%, respectively. Orexin-evoked release was partially extracellular Ca(2+) dependent. 5. Of the other transmitters studied there was a weak orexin A and B stimulation of glutamate release. In contrast K(+) evoked dopamine, glutamate, histamine and serotonin release with pEC(50) and E(max) (% of basal) values of 1.47+/-0.05 (34 mM) and 3430+/-410%, 1.38+/-0.04 (42 mM) and 1240+/-50%, 1.47+/-0.02 (34 mM) and 480+/-10% and 1.40+/-0.05 (40 mM) and 560+/-60% respectively. 6. We conclude that the neuropeptides orexin A and B evoke noradrenaline release from rat cerebrocortical slices.

Animals↗

PubMed2001

Stereochemical applications of the expression of the L-2,3-butanediol dehydrogenase gene in Escherichia coli.

The L-2,3-butanediol dehydrogenase (L-BDH) gene of Brevibacterium saccharolyticum was strongly expressed in Escherichia coli using the tac promoter. However, the stereospecificity of the resulting L-BDH was reduced. The region upstream of the meso-BDH gene of Klebsiella pneumoniae was also involved in the expression of the B. saccharolyticum gene. However, in this case, the resulting L-BDH exhibited more stable stereospecificity. A stereospecificity recognition region was located within the rear sequence (Hpa I site, carboxy terminal) of the BDH open reading frame. Using a transformed strain of E. coli, the conversion of L-acetoin (L-AC), in the commercially available racemic mixture of AC, to L-2,3-butanediol (L-BD) was attempted. As a result, 0.37% L-BD was formed from 1% AC added to the culture.

Acetoin↗

PubMed2001

Manic episode in epilepsy and bipolar I disorder: a comparative analysis of 13 patients.

PURPOSE: To determine whether the manic episode of patients with epilepsy has different characteristics from manic episode of patients with bipolar disorder. METHODS: Interictal manic episodes in patients with epilepsy (epilepsy group) were compared with mood disorders in patients with bipolar I disorder (bipolar group), as defined by the DSM-IV. There were 13 patients (five women and eight men) in each group. RESULTS: Five epilepsy patients had relatives with epilepsy and/or convulsions, and four bipolar patients had relatives with mood disorders. In the epilepsy group, two had substance-related or organic factors associated with the episodes besides epilepsy, and two exhibited a postictal manic state that had the same symptoms as those of their interictal manic episodes. Ten patients of the epilepsy group had dependent-childish behavior. The epilepsy group had fewer severe mood episodes than the bipolar group. Ten epilepsy patients had fluctuating mood disturbances, and eight had rapid cycling of mood episodes. The epileptogenic zone was in the frontal and/or temporal lobes of eight patients and in multiple lobes of two others; it could not be localized in the three remaining patients. CONCLUSIONS: The clinical features of the interictal manic episodes in the epilepsy group were different from those in the bipolar group. The manic episodes of the epilepsy group appeared heterogeneous in their causal factors. An epileptogenic zone in the frontal and temporal lobes seems to play an important role in the mood episodes of the majority of patients with epilepsy.

Adolescent↗

PubMed2001

Comparison of relaxant effects of propofol on methacholine-induced bronchoconstriction in dogs with and without vagotomy.

Propofol has been suggested to have in vivo airway relaxant effects, although the mechanism is still unclear. In this study, we determined whether propofol could antagonize methacholine-induced bronchoconstriction and determined whether vagotomy modifies this relaxant effect. Fourteen mongrel dogs anaesthetized with pentobarbital and pancuronium were assigned to a control group (n=7) and a vagotomy group (n=7). The trachea was intubated with a special endotracheal tube that had a second lumen for insertion of the bronchoscope. Bronchial cross-sectional area, which was monitored continuously through the bronchoscope, was measured with image analysis software. Bronchoconstriction was elicited with methacholine (0.5 microg kg(-1) + 5.0 microg kg(-1) min(-1)) until the end of the experiment. Thirty minutes after the start of methacholine infusion, propofol 0, 0.2, 2.0 and 20 mg kg(-1) was administered. Changes in bronchial cross-sectional area were expressed as percentages of the basal area. Plasma concentrations of propofol and catecholamine were measured by high-performance liquid chromatography. Maximal inhibition (bronchoconstriction = 0%, baseline = 100%) and IC50 (concentration producing 50% inhibition of maximal effect) produced by propofol was obtained from each concentration-response curve using a curve-fitting program. Methacholine decreased bronchial cross-sectional area to 49.3% (95% confidence interval 38.5-60.1%) and 45.3% (34.8-55.7%) of the baseline value. Propofol 20 mg kg(-1) significantly reversed this effect: bronchial cross-sectional area was reduced to 77.8% (66.2-89.6%) and 75.9% (64.0-87.9) in the control and vagotomy groups respectively. The two groups did not differ significantly in the maximal inhibitory effect of propofol [control group, 61.1% (46.3-75.9%), vagotomy group, 64.2% (40.1-88.3%)] or pIC50 [control group 5.03 (4.55-5.51), vagotomy group 4.86 (4.49-5.24)]. Therefore, the relaxant effects of propofol on methacholine-induced bronchoconstriction may not be mediated centrally. Propofol may relax airway smooth muscles directly or through the peripheral vagal pathway.

Anesthetics, Intravenous↗

PubMed2001

Crystal structure of meso-2,3-butanediol dehydrogenase in a complex with NAD+ and inhibitor mercaptoethanol at 1.7 A resolution for understanding of chiral substrate recognition mechanisms.

The crystal structure of a ternary complex of meso-2,3-butanediol dehydrogenase with NAD+ and a competitive inhibitor, mercaptoethanol, has been determined at 1.7 A resolution by means of molecular replacement and refined to a final R-factor of 0.194. The overall structure is similar to those of the other short chain dehydrogenase/reductase enzymes. The NAD+ binding site, and the positions of catalytic residues Ser139, Tyr152, and Lys156 are also conserved. The crystal structure revealed that mercaptoethanol bound specifically to meso-2,3-butanediol dehydrogenase. Two residues around the active site, Gln140 and Gly183, forming hydrogen bonds with the inhibitor, are important but not sufficient for distinguishing stereoisomerism of a chiral substrate.

Alcohol Oxidoreductases↗

PubMed2001

Oxymonads are closely related to the excavate taxon Trimastix.

Despite intensive study in recent years, large-scale eukaryote phylogeny remains poorly resolved. This is particularly problematic among the groups considered to be potential early branches. In many recent systematic schemes for early eukaryotic evolution, the amitochondriate protists oxymonads and Trimastix have figured prominently, having been suggested as members of many of the putative deep-branching higher taxa. However, they have never before been proposed as close relatives of each other. We amplified, cloned, and sequenced small-subunit ribosomal RNA genes from the oxymonad Pyrsonympha and from several Trimastix isolates. Rigorous phylogenetic analyses indicate that these two protist groups are sister taxa and are not clearly related to any currently established eukaryotic lineages. This surprising result has important implications for our understanding of cellular evolution and high-level eukaryotic phylogeny. Given that Trimastix contains small, electron-dense bodies strongly suspected to be derived mitochondria, this study constitutes the best evidence to date that oxymonads are not primitively amitochondriate. Instead, Trimastix and oxymonads may be useful organisms for investigations into the evolution of the secondary amitochondriate condition. All higher taxa involving either oxymonads or Trimastix may require modification or abandonment. Affected groups include four contemporary taxa given the rank of phylum (Metamonada, Loukozoa, Trichozoa, Percolozoa), and the informal excavate taxa. A new "phylum-level" taxon may be warranted for oxymonads and Trimastix.

Animals↗

PubMed2001

Changes in sex steroids, gonadotropins, prolactin, and inhibin in pregnant and nonpregnant Japanese black bears (Ursus thibetanus japonicus).

We examined changes in the concentrations of serum progesterone (P4), estradiol-17beta (E2), FSH, LH, prolactin (PRL), and inhibin to determine their interaction and their effect on the reproductive endocrine controls of pregnant and nonpregnant female Japanese black bears. Fourteen female bears were used in this study over a 2-yr period. In the first year, six of the bears were divided into two groups; a pseudopregnant group and a nonpregnant group. In the second year, the remaining eight bears were also divided into two groups; a pregnant group and a nonpregnant group. Pregnant and pseudopregnant bears had similar P4 trends with both groups exhibiting a significant increase in December, which is the suspected time of implantation in pregnant bears. These trends correlated with an increase in PRL levels, whereas low levels of LH were maintained throughout the year. Nonpregnant bears maintained low concentrations of P4, and compared with pregnant and pseudopregnant bears, they also exhibited a delayed elevation in PRL. Luteinizing hormone activity varied among individual animals, but regardless of reproductive status, fluctuation patterns of E2, FSH, and inhibin did not differ among bears. Our results suggest that PRL may play a luteotropic role in both pregnant and pseudopregnant bears, and is possibly responsible for inducing reactivation of the dormant corpus luteum that precedes implantation in the Japanese black bear.

Animals↗

PubMed2001

A comparison of the relaxant effects of olprinone and aminophylline on methacholine-induced bronchoconstriction in dogs.

UNLABELLED: IV aminophylline, a nonselective phosphodiesterase (PDE) inhibitor, is often used to treat an asthma attack during anesthesia. However, in some instances, aminophylline-resistant attacks are observed. Selective PDE3 inhibitors are now clinically available and have been reported to produce bronchodilation. Thus, we compared the relaxant effects of olprinone, a novel PDE3 inhibitor, and aminophylline on methacholine-induced bronchoconstriction. Dogs were anesthetized with pentobarbital. Bronchoconstriction was elicited with methacholine (0.5 microg/kg + 5.0 microg. kg(-1). min(-1)) and assessed as percentage of changes in the bronchial cross-sectional area (BCA; basal = 100%) monitored by bronchoscope. Initially, the relaxant effects of olprinone (n = 8; 0-1000 microg/kg) and aminophylline (n = 8; 0-50 mg/kg) were compared. The bronchial cross-sectional areas were assessed before and 30 min after methacholine infusion began and 5 min after each dose of olprinone or aminophylline. We then determined whether propranolol (0.4 mg/kg) reversed the relaxation induced by olprinone (1000 microg/kg) and aminophylline (50 mg/kg). Olprinone and aminophylline dose-dependently antagonized bronchoconstriction by 56.2% +/- 21.3% (SD) and 68.0% +/- 30.3% with -log 50% effective dose (mean) of 4.80 +/- 0.38 (15.8) microg/kg and 1.96 +/- 0.42 (10.9) mg/kg, respectively. Aminophylline 50 mg/kg significantly increased plasma epinephrine, whereas olprinone did not. In addition, propranolol significantly reduced aminophylline-induced relaxation, but not olprinone-induced relaxation. Therefore, the relaxant effects of olprinone are independent of plasma epinephrine, whereas aminophylline effects may partially result from increased circulating concentrations of epinephrine. IMPLICATIONS: We compared the relaxant effects of olprinone and aminophylline on methacholine-induced bronchoconstriction in dogs. The relaxant effects of olprinone are independent of plasma epinephrine, whereas the aminophylline effects may be partly caused by an increase in plasma epinephrine.

Aminophylline↗

PubMed2001

Bronchoconstrictive and relaxant effects of lidocaine on the airway in dogs.

OBJECTIVE: Intravenous lidocaine commonly is used to treat ventricular arrhythmias and to attenuate reflex airway constriction and intracranial pressure elevation during airway manipulation in intensive care units. There is much controversy as to the actions of lidocaine on the airway, so the aim of this study was to compare, in detail, the actions of lidocaine with those of bupivacaine and procaine on airway caliber and the associated changes in plasma catecholamine concentrations in the dog. DESIGN: Prospective, randomized, controlled experimental in vivo and in vitro study. SETTING: A university research laboratory. SUBJECTS: Mongrel dogs. INTERVENTIONS: In the first experiment, we evaluated the effects of intravenous local anesthetics--lidocaine 0-10 mg/kg (n = 7), bupivacaine 0-2.5 mg/kg (n = 7), or procaine 0-20 mg/kg (n = 7)--on basal airway tone. In second experiment, histamine (10 microg/kg + 500 microg x kg(-1) x hr(-1), n = 6), serotonin (10 microg/kg + 500 microg x kg(-1) x hr(-1), n = 7), and methacholine (0.5 microg/kg + 300 microg x kg(-1) x hr(-1), n = 7) were infused to determine the effects of lidocaine (0-10 mg/kg) on agonist-induced bronchoconstriction. In addition, the actions of lidocaine on vagal nerve stimulation were examined (n = 7). MEASUREMENTS AND MAIN RESULTS: Bronchial cross-sectional area at the third bronchial bifurcation of dogs was monitored continuously through a fiberoptic bronchoscope. In the first experiment, all local anesthetics produced a dose-dependent decrease in basal bronchial cross-sectional area. In the second experiment, lidocaine significantly potentiated histamine and serotonin-induced bronchoconstriction. In contrast, lidocaine antagonized methacholine- and vagal nerve stimulation-induced bronchoconstriction. CONCLUSION: We have clearly demonstrated that lidocaine may produce direct bronchoconstriction and worsen some agonist-induced bronchoconstriction, but it prevents reflex airway constriction. Therefore, we suggest that this agent be used with caution in asthmatics.

Anesthetics, Local↗

PubMed2001

GJB2 (connexin 26) mutations and childhood deafness in Thailand.

HYPOTHESIS: The purpose of this study was to elucidate whether GJB2 mutations are responsible for childhood deafness in Southeast Asia. BACKGROUND: GJB2 mutations are responsible for a large part of childhood deafness in many countries. In Whites, there is a common mutation (35delG) that accounts for about 70 to 80% of the GJB2 mutations. Previously, we and others reported a common GJB2 mutation (235delC) in Japanese patients with prelingual deafness. The association of the 235delC mutation with a single haplotype suggested a founder effect of the mutation. METHODS: We analyzed the GJB2 gene in 17 deaf patients from 12 unrelated families in Thailand. Genomic DNA was extracted from peripheral lymphocytes of each patient and the entire coding region of the GJB2 gene was sequenced. RESULTS: GJB2 mutations were found in 4 patients in 3 families. Patient 1 was a homozygote of 235delC. Patient 2 was a compound heterozygote of 235delC and W24X (71G --> A). Patient 3A and 3B (in 1 family) were heterozygotes of a novel mutation M34L (100A --> T). CONCLUSION: The 235delC mutation may be widely distributed in Asian countries outside of Japan.

Child↗

PubMed2001

Clarification of the relationship between the members of the family Thermomonosporaceae on the basis of 16S rDNA, 16S-23S rRNA internal transcribed spacer and 23S rDNA sequences and chemotaxonomic analyses.

To resolve relationships between members of the family Thermomonosporaceae, phylogenetic analyses using three sets of nucleotide sequences from 16S rDNA, 23S rDNA and the 16S-23S internal transcribed spacer (ITS) were carried out. Nearly all species of the family were included in this study. On the basis of congruous phylogenetic results and chemotaxonomic data, the following proposals are made. First, Actinomadura libanotica, Actinomadura aurantiaca, Actinomadura glomerata and Actinomadura longicatena are transferred to the genus Actinocorallia as Actinocorallia libanotica comb. nov., Actinocorallia aurantiaca comb. nov., Actinocorallia glomerata comb. nov. and Actinocorallia longicatena comb. nov., respectively. All the species of this genus are phylogenetically coherent and of phospholipid type PII (presence of phosphatidylethanolamine), distinguishing them from other Actinomadura species that are of phospholipid type PI (absence of diagnostic phospholipids). Second, Excellospora viridilutea is transferred to the genus Actinomadura as Actinomadura viridilutea comb. nov. As a result of the proposed transfers, the family Thermomonosporaceae now contains four genera Thermomonospora, Actinomadura, Actinocorallia and Spirillospora. The genus Actinocorallia and family Thermomonosporaceae are redescribed.

Actinomycetales↗