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Biomedical subjects

K Aida

Publications and source records attributed to K Aida.

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

Enhancement of blood-brain barrier permeability by sodium caprate.

We examined the effect of sodium caprate on the integrity of the tight junctions of brain capillary endothelial cells, using a modified in-situ brain perfusion technique. Model hydrophilic compounds used were [3H]mannitol, [14C]sucrose, [3H]PEG900, [3H]PEG4000, FITC-dextran 4000, FITC-dextran 20000 and FITC-dextran 70000. The brain distribution volume of [14C]sucrose was significantly increased by sodium caprate in a concentration-dependent manner. The effective minimum concentration was 10mM. Furthermore, the effects of sodium caprate on the distribution volumes of hydrophilic compounds, [3H]mannitol, [14C]sucrose, [3H]PEG900, [3H]PEG4000, FITC-dextran 4000, FITC-dextran 20000 and FITC-dextran 70000, showed a molecular weight dependence. A plot of apparent permeation clearance against diffusion coefficient values suggested that 20 mM sodium caprate induced pores so large that the above compounds could pass through the blood-brain barrier with negligible friction within the pore. Our results showed that intracarotid sodium caprate perfusion could enhance the permeation of hydrophilic compounds through the blood-brain barrier.

Animals↗
PubMed1999

Expression of a recombinant molt-inhibiting hormone of the kuruma prawn Penaeus japonicus in Escherichia coli.

The crustacean molt-inhibiting hormone (MIH) suppresses ecdysteroid synthesis by the Y-organ. The MIH of the kuruma prawn Penaeus japonicus has recently been isolated and its cDNA cloned. In this study, we expressed the MIH in Escherichia coli to obtain a large quantity of this hormone with biological activity. The MIH cDNA was processed and ligated into an expression plasmid. E. coli was transformed with this plasmid, and then the recombinant MIH (r-MIH) was expressed. The r-MIH was put through the refolding reaction and was purified by reverse-phase HPLC. N-terminal amino acid sequence and time-of-flight mass spectral analyses supported the idea that the r-MIH had the entire sequence. By in vitro bioassay using the Y-organ of the crayfish, the r-MIH was found to be comparable to natural MIH in inhibiting ecdysteroid synthesis.

Amino Acid Sequence↗
PubMed1999

[Calcium-sensing receptor and its related diseases].

The cloning of a G protein-coupled, extracellular calcium-sensing receptor (CaSR) provided direct evidence that Ca(2+)-sensing can occur through receptor-mediated activation of G proteins and their associated downstream regulators of cellular function. CaSR transcripts and protein are present in various tissues that are involved in Ca2+ homeostasis and that do not have well-established roles in Ca balance as well. The physiological relevance of the CaSR has been established by identifying inherited hyper-and hypocalcemia disorders resulting from CaSR mutations: familial hypocalciuric hypercalcemia and neonatal severe hyperparathyroidism result from inactivating CaSR mutations while autosomal dominant hypocalcemia is caused by activating mutations. CaSR may also play a role in water metabolism. Calcimimetics that activate CaSR are undergoing clinical trials and might prove effective in manipulation of serum calcium concentration and urinary calcium excretion through CaSR activities.

Calcium Metabolism Disorders↗
PubMed1998

Structural and expression analyses of gonadotropin Ibeta subunit genes in goldfish (Carassius auratus).

Gonadotropin (GTH) is a pituitary glycoprotein hormone that regulates gonadal development in vertebrates. In teleosts, it is considered that two types of GTH, GTH I (follicle-stimulating hormone-like GTH) and GTH II (luteinizing hormone-like GTH), are produced in the pituitary, and their molecules are comprised of common alpha and distinct beta subunits. In this study, we describe the complete structure and 5'-flanking regulatory region of two distinct genes encoding GTH Ibeta in goldfish, Carassius auratus. The two goldfish GTH Ibeta genes, gfGTHIbeta-1 and gfGTHIbeta-2, span 1719 and 1545 base pairs (bp) nucleotides, respectively, and there is a high sequence identity (92.1%) between the coding regions. Both genes consist of three exons separated by two introns as in mammalian FSH beta genes. The locations of the first intron and second intron showed a well-conserved pattern similar to those of mammalian FSH beta genes. Inspection of the 5'-flanking region of the gfGTHIbeta-1 and gfGTHIbeta-2 (approximately 1.4 and 1.1kb, respectively) revealed the presence of several putative cis-acting elements, including the gonadotrope-specific element, gonadotropin-releasing hormone responsive element, and half steroid hormone responsive elements. Interestingly, some of their elements were located contiguously between -187 and -124bp upstream from a TATAA sequence. Reverse transcription polymerase chain reaction confirmed that these two genes are expressed in the pituitary of individual fish. These results, taken together, demonstrate that there are at least two functional genes encoding GTH Ibeta, probably due to the tetraploidy of goldfish. The unique locations of the cis-acting elements in the GTH Ibeta genes suggest they may be involved in the expression of the goldfish GTH Ibeta gene.

Amino Acid Sequence↗
PubMed1998

Purification and molecular cloning of a chitinase expressed in the hepatopancreas of the penaeid prawn Penaeus japonicus.

A protein with chitinase activity was purified from the hepatopancreas of the penaeid prawn Penaeus japonicus, and the amino acid sequences of several amino acid fragments were determined. A cDNA clone was isolated and sequenced which contained the coding sequence of the enzyme. The conceptually translated protein (named Pjchi-3) was a member of the chitinase family based on sequence similarities to chitinases of non-crustacean species, as was the case with Pjchi-1 and 2, two chitinase homologues previously isolated from P. japonicus.

Amino Acid Sequence↗
PubMed1998

Hyperglycaemic hormones inhibit protein and mRNA synthesis in in vitro-incubated ovarian fragments of the marine shrimp Penaeus semisulcatus.

The present work shows for the first time that peptides belonging to the Crustacean hyperglycaemic hormone family (CHH-family hormones) from Penaeus japonicus affect protein and mRNA synthesis in in vitro-incubated ovarian explant fragments removed from vitellogenic females of Penaeus semisulcatus. Reduced levels of protein synthesis, determined by TCA-precipitable 35S-labeled proteins, were found in the presence of crude sinus gland extracts from both P. semisulcatus and P. japonicus. A similar inhibitory effect compared to controls was found with each of the seven CHH-family peptides. Non-CHH-family peptides did not reduce protein synthesis. Crude sinus gland extracts prepared from P. semisulcatus were at least 20-fold more effective than sinus gland extracts of P. japonicus. The inhibition level was directly related to the concentration of the peptide in the incubation media, but its degree varied among the different tested peptides. The profile of proteins synthesized during in vitro incubation was analyzed using polyacrylamide gel electrophoresis under denatured and reduced conditions (SDS-PAGE), followed by autoradiography. Synthesis of several proteins was reduced, including proteins with electrophoretic mobility similar to that of vitellin. Immunoprecipitation with antiserum prepared against native ovarian vitellin confirmed the inhibitory effect of CHH-family peptides on vitellin synthesis. The crude sinus gland extract and CHH-family peptides also inhibited RNA synthesis, as determined by [3H]uridine incorporation into mRNA of ovarian fragments. It is concluded that in addition to their role in carbohydrate metabolism, CHH-family peptides may also influence ovarian physiology in crustaceans.

Amino Acid Sequence↗
PubMed1998

Two differing salmon GnRH precursor mRNAs are co-expressed in the brain of sockeye salmon.

The localization of two salmon-type gonadotropin-releasing hormone (sGnRH) precursors, pro-sGnRH-I (short type) and pro-sGnRH-II (long type), was investigated by using in situ hybridization techniques in the brain of the landlocked sockeye salmon, Oncorhynchus nerka. We used 30-mer oligonucleotide probes complementary to pro-sGnRH-I and pro-sGnRH-II cDNA. No significant differences were observed in the localization of sGnRH neurons expressing pro-sGnRH-I and pro-sGnRH-II mRNAs; both were expressed in the olfactory nerve, the olfactory bulbs, the regions between the olfactory bulb and telencephalon, the ventral telencephalon, the preoptic area, and the hypothalamus. Almost all sGnRH neurons examined co-expressed both precursors. The expression of two sGnRH precursors in the same neuron and the wide distribution of such neurons in the brain suggest that there are no functional differences between the two precursors.

Animals↗
PubMed1998

Ontogenic development of salmon GnRH and chicken GnRH-II systems in the brain of masu salmon (Oncorhynchus masou).

Ontogenic development of salmon gonadotropin-releasing hormone (GnRH) and chicken GnRH-II systems in masu salmon (Oncorhynchus masou) was examined. Salmon GnRH was first detected by radioimmunoassay in the embryo on day 36 after fertilization. Salmon GnRH-immunoreactive fibers were detected initially by immunocytochemistry in the vicinity of the olfactory placode of the embryo (day 36) and were distributed widely in the brain as well as in the pituitary gland of fish just after hatching (day 80). Salmon GnRH-immunoreactive neuronal somata were first detected about 6 months after fertilization in the rostroventral brain area, ranging from the olfactory nerve to the preoptic area. Salmon GnRH neuronal somata were detected earlier by in situ hybridization than by immunocytochemistry. Neuronal somata expressing salmon GnRH mRNA were first detected in the vicinity of the olfactory epithelium on day 40 and then were seen to be migrating from the olfactory epithelium, along the olfactory nerve, on day 60 and in the transitional area between olfactory nerve and olfactory bulb on day 80. In the brain, these neurons were first detected in the ventral olfactory bulb on day 80, and thereafter they were also detected in the caudal brain regions. The chicken GnRH-II system was detected later than the salmon GnRH system; chicken GnRH-II was first detected by radioimmunoassay on day 57, and chicken GnRH-II-immunoreactive fibers were first detected on day 67. Chicken GnRH-II-immunoreactive neuronal somata were not detected during the observation period. These results suggest that salmon GnRH neurons derive from the olfactory placode and then migrate into the brain and that salmon GnRH is synthesized before chicken GnRH-II.

Animals↗
PubMed1998

A cross-sectional evaluation of spontaneous platelet aggregation in relation to complications in patients with type II diabetes mellitus.

To clarify the relationship between platelet function and diabetic complications, we investigated spontaneous platelet aggregation (SPA) and agonist-induced platelet aggregation by a particle counting method using light scattering (LS) and by a conventional light transmission method (LT) in 23 age- and sex-matched control subjects and 74 patients with type II diabetes mellitus. We also observed platelets using the FIC-2 (TOA Medical Electronics, Kobe, Japan) flow cytometer and imaging device. Observation by the FIC-2 device showed microaggregates of platelets in samples with increased SPA-LS. SPA-LS was significantly elevated in patients with type II diabetes mellitus as a whole compared with control subjects. SPA-LS also showed significant differences between control subjects and three diabetic patient subgroups with a varying severity of retinopathy, nephropathy, or neuropathy, and the mean values increased along with the increasing severity of complications. On the other hand, although SPA-LT also showed significant differences between these groups, the absolute values were all less than 10%, which we believe does not warrant quantitative analysis. Adenosine-5'-diphosphate (ADP)-induced platelet aggregation failed to show significant differences between controls and subjects with a varying severity of retinopathy by either LS or LT, which indicates that SPA is more sensitive than agonist-induced platelet aggregation in relation to diabetic complications. We observed significant correlations between SPA-LS and the patients' age, hemoglobin A1c (HbA1c) level, plasma fibrinogen level, or 6-keto-PGF1alpha (6KF) to 11-dehydro-thromboxane B2 (TXB2) ratio. Our study demonstrated a close relationship between platelet hyperaggregability and diabetic complications, and a longitudinal prospective study of SPA-LS in diabetic patients is warranted to clarify cause-and-effect relationships.

Cross-Sectional Studies↗
PubMed1998

Isolation of a 65-kDa protein from white muscle of warm temperature-acclimated goldfish (Carassius auratus).

A 65-kDa protein expressed in association with warm temperature acclimation of goldfish (Carassius auratus) was purified from epaxial muscle by successive ion-exchange, gel filtration, and reversed-phase columns while monitoring immuno-reaction with a specific antibody. A total of 517 micrograms of the 65-kDa protein was obtained from 23.4 g of the muscle of 30 degrees C-acclimated fish. The purified 65-kDa protein gave one band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weight was determined to be 65,000 by gel filtration and SDS-PAGE, demonstrating that it consists of a single polypeptide chain; 44 amino acid residues were determined by N-terminal amino acid sequencing. The amino acid stretch was comparatively rich in histidine and phenylalanine. Homology search in the National Biomedical Research Foundation and Swiss-Prot bank did not identify any known amino acid sequence with significant homology to the 44-amino acid stretch of the 65-kDa protein, suggesting it to be a novel protein.

Acclimatization↗
PubMed1998

A statistical study of the branching of the human internal iliac artery.

This study is based on the dissections of 645 pelvic halves of Japanese cadavers. The branching of the internal iliac artery was classified according to Adachi's classification (1928), and the data was compared with previous reports. Type I was predominant in this, as well as, in previous studies. During the course of the present study, some branching forms were different from the types in Adachi's classification. Therefore, this classification was modified into 5 types and 19 groups. Type I-Group 1 was most frequently observed in the modified Adachi's classification, however, the frequency was less than 50% (46.8%). To clarify the basic branching pattern of the original internal iliac artery and to simplify the classification for medical purposes, a new classification system was designed. The superior gluteal, inferior gluteal and internal pudendal arteries were defined as the major branches of the internal iliac artery, and the umbilical artery was excluded from this group. The branching of the internal iliac artery was classified into 4 groups. Almost 80% of the present specimens were included in Group A of the new classification, namely, the internal iliac artery dividing into two major branches, the superior gluteal artery and the common trunk of the inferior gluteal and internal pudendal arteries. This type of branching seemed to be the basic branching pattern for the original internal iliac artery.

Female↗
PubMed1998

[Abnormal hemoglobinopathy (HbE) diagnosed from microcytic hypochromic red blood cells in a 31 year-old Bangladeshian male].

Microcytic hypochromic red blood cells (RBC) were discovered in a 31 year-old Bangladeshi man. Additional laboratory data revealed only slight elevations of LDH and transaminase activities. The patient was clinically asymptomatic and showed no signs of anemia. On this basis, along with biochemical genetic analysis of hemoglobin, a diagnosis of hemoglobinopathy (HbE) was made. HbE is common in southeast Asia with over 30% of the population affected. Most people are asymptomatic. In northern Asia, including Japan, HbE is found in only 0.001% of the population. With ther recent influx of southeast Asians to Japan, care must be taken not to overlook the diagnosis of hemoglobinopathies.

Adult↗
PubMed1998

[Basic and clinical studies on tazobactam/piperacillin in pediatric field].

A drug susceptibility test of the combination drug TAZ/PIPC, which consists of a newly developed beta-lactamase inhibitor, tazobactam (TAZ), and one of penicillin antibiotics, piperacillin (PIPC), with combination ratio of 1:4 in potency, was conducted with stock strains and clinical isolates. The clinical efficacy and safety of its injection was also evaluated in children with a variety of infectious diseases. The results were as follows: 1. In susceptibility test, 114 strains from 4 species of stock strains were treated with 8 drugs, that is, TAZ/PIPC, PIPC, penicillin G (PCG), ampicillin (ABPC), cefotiam (CTM), cefotaxime (CTX), ceftazidime (CAZ), and sulbactam/cefoperazone (SBT/CPZ). Of three clinically isolated species from patients, Staphylococcus aureus (S. aureus) was treated with TAZ/PIPC, PIPC, methicillin (DMPPC), CTM, CTX, and SBT/CPZ, and the others were treated with the same drugs except for DMPPC. The MICs were measured for these bacterial strains inoculated at the concentration of 10(6) CFU/ml. The MIC90 values of TAZ/PIPC against 45 strains of Streptococcus pyogenes (S. pyogenes), one of the stock cultures of Gram-positive cocci, were 0.05 microgram/ml and similar to those of PIPC, CTM, CAZ, and SBT/CPZ. The MICs of TAZ/PIPC for 28 strains of Streptococcus agalactiae (S. agalactiae) were 0.39 microgram/ml and similar to those of PIPC, CTM, CAZ, and SBT/CPZ. As for Gram-negative bacilli, the MIC90 of TAZ/PIPC against 10 strains of Bordetella pertussis (B. pertussis) were 0.10 microgram/ml and similar to those of PIPC. The MIC90 of TAZ/PIPC against 31 strains of Haemophilus influenzae (H. influenzae) were 0.05 microgram/ml and similar to those of PIPC, CTX, and SBT/CPZ. Regarding Gram-positive cocci isolated from patients received this combination drug, the MIC90 of TAZ/PIPC against 2 strains of S. aureus, a non beta-lactamase producing strain and a low-beta-lactamase producing strain, were 0.78 microgram/ml and 3.1 micrograms/ml, respectively; the former value was similar to those of PIPC, DMPPC, CTM, and CTX, and the latter was similar to those of PIPC, DMPPC, CTX, and SBT/CPZ. Of 4 strains of Streptococcus pneumoniae, 2 strains were inhibited at 0.05 microgram/ml, and the others at 1.56 micrograms/ml; both values were similar to those of PIPC, SBT/CPZ. As for Gram-negative bacilli, 6 of 7 strains of H. influenzae did not produce beta-lactamase and 1 strain was a high producer. The MICs of TAZ/PIPC against beta-lactamase nonproducing strains were < or = 0.025 microgram/ml in 5 strains and 0.39 microgram/ml in 1 strain, and the values were similar to those of PIPC and SBT/CPZ. While the MIC of TAZ/PIPC against the high beta-lactamase producing strain was 0.78 microgram/ml; similar to that of SBT/CPZ and smaller than that of PIPC. 2. The results of clinical effects on 7 diseases in 33 cases were as follows: TAZ/PIPC was clinically judged "excellent" in 17 (51.5%); good in 14 (42.4%); fair in 2 (6.1%). No case with no response was seen in this study, and the total efficacy rate of "excellent" and "good" was 93.9%. 3. Bacteriological effects were evaluated in 17 strains of 4 species, and all of them were eradicated. 4. Adverse reactions were judged in 35, which consisted of 33 in which the clinical effects were evaluated and 2 dropped from this study. Of these cases, diarrhea was observed in 4 (11.4%). 5. Laboratory tests revealed an increase in platelets in 1 of 32 cases (3.1%), and eosinophilia in 2 of 29 cases (6.9%). Biochemical profile showed an increase in GPT alone and abnormal increases in both GOT and GPT in 1 each out of 21 cases.

Acute Disease↗
PubMed1997

Reciprocal size-effect relationship of the key residues in determining regio- and stereospecificities of DHEA hydroxylase activity in P450 2a5.

Collectively, the P450 2a4/2a5 system hyrdoxylates DHEA in at least three positions (7alpha, 7beta, and 2alpha). An individual P450, however, exhibits high specificity to one of these products. Using site-directed mutagenesis of mP450 2a5 from the wild mouse Mus minutoides and bacterial expression, we have associated the function of residues 117, 209, and 481 with the respective specificity observed in each P450. Ala at position 117 determines the 7beta-hydroxylase activity, whereas Val at this position defines the 2alpha-hydroxylase activity. Leu at position 209 is essential for high DHEA 7alpha-hydroxylase activity. The substitutions of residue 481 with various hydrophobic amino acids elicited a profound alteration of the specific hydroxylation rates, but did not influence the regio- and stereospecificities at either of the three positions of DHEA. The alterations caused by residue 481 also depended on the residue identity at position 117 or 209. The results indicate that the sizes of several key residues obey a concerted reciprocal relationship whereby the substrate pocket of the P450s adjusts to accommodate DHEA. A limited molecular modeling study successfully correlates DHEA binding to experimental DHEA hydroxylase activities for a series of mutants at key positions.

Amino Acid Sequence↗
PubMed1997

Activation of salmon GnRH mRNA expression prior to differentiation of precocious males in Masu salmon.

Changes in salmon gonadotropin-releasing hormone (sGnRH) mRNA levels in the brain of underyearling male masu salmon, Oncorhynchus masou, were investigated to clarify sGnRH participation in differentiation of precocious males. Fish were immature with low gonadosomatic index (GSI < 0.100%) on April 16 and May 7. On June 11, fish were differentiated into two groups: future precocious males and immature males. Fish in the former group had high GSI (0.203%) with proliferation of primary spermatocytes in the testis, while the latter had low GSI (0.055%) with primary spermatogonia. sGnRH mRNA levels (the number of neurons expressing sGnRH mRNA and the total number of silver grains per unit area) in the ventral telencephalon (VT) and in the VT plus preoptic area (POA) already increased in May before the differentiation of precocious males. GSI was positively correlated with sGnRH mRNA levels in the VT and in the VT plus POA in April, and with mRNA levels in the POA in May. Activated sGnRH synthesis is concluded to be related to the appearance of precocious males in masu salmon.

Animals↗
PubMed1997

Molecular cloning of the cDNAs encoding two gonadotropin beta subunits (GTH-I beta and -II beta) from the goldfish, Carassius auratus.

Two types of cDNAs (GTH-I beta and -II beta) that encode the beta subunit of goldfish gonadotropin were cloned from a goldfish pituitary cDNA library. The nucleotide sequence of GTH-I beta cDNA was 616 bp long, encoding 130 amino acids, and that of GTH-II beta was 552 bp long, encoding 140 amino acids. These two types of goldfish GTH beta subunits showed an identity of 52% in the nucleotide sequence and 38% in the amino acid sequence. When compared to mammalian GTH beta subunits, goldfish GTH-I beta showed higher homology to FSH-beta s than LH-beta s, and goldfish-II beta to LH-beta s. Genomic Southern blot analysis revealed that cyprinid species harbored genes which were homologous to goldfish GTH-I beta and -II beta, demonstrating the duality of GTH in cyprinid fish as has been shown in other teleost fish. Northern blot analysis of GTH-I beta and -II beta mRNAs in goldfish at differing stages of ovarian maturity (immature, maturing, mature, and regressed) showed that both GTH-I beta and -II beta mRNA levels increased with the progression of maturity and declined in regressed stage. These results suggested that gonadal development in the goldfish was regulated by the two GTHs.

Amino Acid Sequence↗