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Biomedical subjects

H Hirose

Publications and source records attributed to H Hirose.

At least 163 records · Page 9Linked to original sources
PubMed1996

Two hypothetical proteins of human aortic adventitia, with Ig kappa, collagenous, and aromatic-rich motifs.

Two of five clones, selected from an expression library of aortic adventitia, encode unique hypothetical proteins sharing sequences of Ig kappa, gly/pro rich (collagenous) motifs, and aromatic motifs that occur in several proteins of the extracellular matrix. Both proteins have a similar domain structure with at least 8 regions: (1) Ig kappa (84-120 residues in length); (2) ser/thr-rich motif (44-63); (3) a second Ig kappa motif (9-12); (4) either a possible calcium-binding motif or a gly/pro rich sequence (35-43); (5) an aromatic rich sequence (6-7); (6) another gly/pro rich sequence (62-72); (7) a third Ig kappa sequence (26-28); and (8) a C-terminal 68-70 residue sequence with another aromatic motif.

Amino Acid Sequence↗
PubMed1996

Defective fatty acid-mediated beta-cell compensation in Zucker diabetic fatty rats. Pathogenic implications for obesity-dependent diabetes.

Although obesity is associated with insulin resistance, most obese humans and rodents remain normoglycemic because of compensatory hyperinsulinemia. This has been attributed to beta-cell hyperplasia and increased low Km glucose metabolism of islets. Since free fatty acids (FFA) can induce these same beta-cell changes in normal islets of Wistar rats and since plasma FFA are increased in obesity, FFA could be the signal from adipocytes that elicits beta-cell compensation sufficient to prevent diabetes. To determine if FFA-induced compensation is impaired in islets of rats with a diabetogenic mutation, the Zucker diabetic fatty (ZDF) rat, we cultured islets from 6-week-old obese (fa/fa) rats that had compensated for obesity and apparently normal islets from lean ZDF rats (fa/+) in 0, 1, or 2 mM FFA. Low Km glucose usage rose 2.5-fold in FFA-cultured control islets from age-matched Wistar rats, but failed to rise in either the precompensated islets of ZDF rats or in islets of lean ZDF rats. Bromodeoxyuridine incorporation increased 3.2-fold in Wistar islets but not in islets from obese or lean ZDF rats. Insulin secretion doubled in normal islets cultured in 2 mM FFA (p < 0.01) but increased only slightly in islets from lean ZDF rats (not significant) and declined in islets from obese ZDF rats (p < 0.05). We conclude that, unlike the islets of age-matched Wistar rats, islets of 6-week-old heterozygous and homozygous ZDF rats lack the capacity for FFA-induced enhancement of beta-cell function.

Animals↗
PubMed1996

Influence of CO2 tension on hepatic hemodynamics during portal arterialization.

We investigated the effect of portal arterialization (PA) on hepatic energy metabolism and hepatic hemodynamics. Portal perfusion flow rate with arterial blood was 25% of the preperfusion portal flow. During PA up to 120 min, hepatic energy metabolism was maintained from the aspects of ATP, energy charge, and arterial ketone body ratio. However, during this PA, carbon dioxide tension (25-35 mm Hg) in arterial blood was lower than that in normal portal vein blood and portal vein resistance (PVR) was significantly increased during perfusion compared with that at preperfusion. When carbon dioxide tension (50-63 mm Hg) in arterial blood was made equivalent to that in normal portal vein blood by controlling the respiratory conditions, PVR was not increased during PA up to 120 min. It was suggested that PCO2 in perfusion blood should change PVR, while it should not change hepatic energy metabolism when portal perfusion flow rate with arterial blood was 25% of the preperfusion portal flow.

Animals↗
PubMed1996

Partial amino acid sequence of a novel 40-kDa human aortic protein, with vitronectin-like, fibrinogen-like, and calcium binding domains: aortic aneurysm-associated protein-40 (AAAP-40) [human MAGP-3, proposed].

A microfibrillar protein (40 kDa) purified from the adventitia of the human abdominal aorta is immunoreactive with IgG harvested from the wall of abdominal aortic aneurysms. We have partially sequenced this protein and found that it has fibrinogen alpha-, beta-, and gamma-like domains, a vitronectin-like domain, and a possible site for binding calcium. Because of homologies with other microfibril-associated glycoproteins and because it is the third member of the family to be characterized in man, we suggest the name MAGP-3.

Amino Acid Sequence↗
PubMed1996

Differential effects of overexpressed glucokinase and hexokinase I in isolated islets. Evidence for functional segregation of the high and low Km enzymes.

Glucose-stimulated insulin secretion is believed to require metabolism of the sugar via a high Km pathway in which glucokinase (hexokinase IV) is rate-limiting. In this study, we have used recombinant adenoviruses to overexpress the liver and islet isoforms of glucokinase as well as low Km hexokinase I in isolated rat islets of Langerhans. Glucose phosphorylating activity increased by up to 20-fold in extracts from islets treated with adenoviruses containing the cDNAs encoding either tissue isoform of glucokinase, but such cells exhibited no increase in 2- or 5-[3H]glucose usage, lactate production, glycogen content, or glucose oxidation. Furthermore, glucokinase overexpression enhanced insulin secretion in response to stimulatory glucose or glucose plus arginine by only 36-53% relative to control islets. In contrast to the minimal effects of overexpressed glucokinases, overexpression of hexokinase I caused a 2.5-4-fold enhancement in all metabolic parameters except glycogen content when measured at a basal glucose concentration (3 mM). Based on measurement of glucose phosphorylation in intact cells, overexpressed glucokinase is clearly active in a non-islet cell line (CV-1) but not within islet cells. That this result cannot be ascribed to the levels of glucokinase regulatory protein in islets is shown by direct measurement of its activity and mRNA. These data provide evidence for functional partitioning of glucokinase and hexokinase and suggest that overexpressed glucokinase must interact with factors found in limiting concentration in the islet cell in order to become activated and engage in productive metabolic signaling.

Animals↗
PubMed1996

A novel hypothesis to explain the hemorrhagic and connective tissue manifestations of Ebola virus infection.

The hemorrhagic and connective tissue complications of infection with Ebola virus are poorly understood. While searching for homologies and motifs of the aortic aneurysm-associated autoantigenic protein 40 kDa (AAAP-40), we have noted some short sequences (possibly shared epitopes) that occur in the envelope glycoprotein (40 kDa) of the Ebola virus. As a first step toward determining whether molecular mimicry of human matrix proteins by the Ebola virus protein might explain some of the severe connective tissue manifestations of infection, we have tested whether immunoglobulin (IgG) purified from the sera of patients with abdominal aortic aneurysm (AAA) are immunoreactive with the 40-kDa protein of the Ebola virus. Immunoblots of soluble Ebola proteins (strain Mayinga/Zaire) were probed with IgG's purified from the sera of eight patients with AAA and two healthy young control volunteers. The proteins were also probed with IgG extracted from the walls of two surgical aneurysm specimens. Serum IgG from eight consecutively studied AAA patients was immunoreactive with an Ebola virus protein of 40 kDa, consistent with the envelope glycoprotein. IgG's extracted from the walls of two AAAs were also reactive. The control sera were not reactive. In addition to the Ebola sequences in AAAP-40, an Ebola sequence also occurs in the microfibril-associated glycoprotein-4 (MAGP-4), which is distributed ubiquitously throughout connective tissue with elastin. We hypothesize that the catastrophic hemorrhagic and connective tissue complications of Ebola virus infection may be the result of these shared epitopes.

Aged↗
PubMed1996

Two types of apoptotic cell death of rat central nervous system-derived neuroblastoma B50 and B104 cells: apoptosis induced during proliferation and after differentiation.

We describe here two types of apoptotic cell death observed in the rat CNS-derived neuroblastoma B50 and B104 cells. One type was induced by dibutyryl cyclic AMP (DBcAMP) after differentiation, and the other was induced by treatment of proliferating cells with cycloheximide. When B50 and B104 cells were treated with 1 mM DBcAMP in the presence of 0.5% fetal calf serum, they began to extend neurites within 12 h and differentiated into neurons at 24 h, as reported previously. However, further cultivation with DBcAMP for up to 72 h led to flotation and, finally, death. Death was by apoptosis as shown by chromatin condensation and DNA fragmentation. Addition of a protein kinase A inhibitor or removal of DBcAMP after differentiation suppressed apoptosis, indicating the involvement of cyclic AMP and protein kinase A in apoptotic cell death. Cell death was also induced in proliferating cells without neurite outgrowth by treatment with cycloheximide. The death was also judged to be by apoptosis based on chromatin condensation and apoptotic body formation, although DNA fragmentation into small sizes was not detected. Both types of cell death showed similar responses to inhibitors for protein kinases and protein phosphatases.

Animals↗
PubMed1996

Hyperacuity test to evaluate vision through dense cataracts; research preliminary to a clinical study. III. Data on normal subjects obtained with and without a pseudo-nuclear cataract 6/60 (20/200) at the Aravind Eye Hospital, Madurai, India.

Using a recently discussed three-point Vernier alignment test, data were obtained on normal subjects with and without a pseudo-nuclear cataract 6/60 (20/200) at the Aravind Eye Hospital, Madurai, India. This experiment is a critical control exercise. The pseudo-cataract caused measurably and predictably reduced Vernier alignment thresholds, there were no meaningful differences between eyes, and necessary modifications in protocol for a later clinical study were defined.

Adolescent↗
PubMed1996

Hyperacuity test to evaluate vision through dense cataracts; research preliminary to a clinical study. IV. Data on patients with macular degeneration and minimal media disorders obtained with and without a pseudo-nuclear cataract 6/60 (20/200) at the Aravind Eye Hospital, Madurai, India.

Using a recently discussed three-point Vernier alignment test, data were obtained on patients with macular dysfunctions with and without a pseudo-nuclear cataract 6/60 (20/200) at the Aravind (Free) Eye Hospital, Madurai, India. The pseudo-cataract caused measurably and predictably reduced Vernier alignment thresholds, and necessary modifications deemed to be necessary in the protocol for later study are defined.

Cataract↗
PubMed1996

Evidence of direct recognition subset in xeno-reactive helper T cells.

There are two functional subsets of alloreactive helper T cells: one recognizes the alloantigens on self-antigen-presenting cells (APCs), and the other recognizes the alloantigens on allo-APCs. In this study, we analyzed which specific Th cells have a possible effect on concordant-xenograft rejection responses and how Th cells recognize xeno-antigens. In the proliferative response stimulated with spleen cells obtained from rats (r-SPC), mouse T cells (m-Tc) were not inhibited by GK1.5 (CD4) or 2.43 (CD8) antibodies. In a xeno-mixed lymphocyte reaction, m-Tc that included APC (APC(+)) proliferated when stimulated with r-SPC APC(+) or APC(-). In contrast, B6 T cell APC(-) proliferated only when stimulated with r-APC(+)SPC but not when stimulated with APC(-). The m-Tc lines responded to F344 SPC APC(+) but not to SPC APC(-); however, the m-Tc line did not respond to SPC from another rat strain. We hypothesize that both CD4+ Th and CD8+ Th are included in the concordant xeno-reactive Th; there are both xeno-APC-restricted Th and self-APC-restricted Th; and xeno-APC-restricted Th recognizes xeno-major histocompatibility complexes.

Animals↗
PubMed1996

[Bacteriological studies of travellar's diarrhoea. 5) Analysis of enteropathogenic bacteria at Osaka Airport Quarantine Station from January 1992 through September 3rd, 1994].

During the last 2 years and 8 months before the closure of Osaka Airport Quarantine Station (from Jan. 1992 to Sep. 3, 1994), a total of 7,421,909 overseas travellers were quarantined. 15,919 reported themselves of suffering from diarrhoea. Bacteriological examination of a total of 6,031 individuals' stools were performed. 1) Various enteropathogenic bacteria were isolated from 31.2% of the stools examined. Isolated species were as follows: Plesiomonas shigelloides, 1,127 cases (59.9%); Vibrio parahaemolyticus, 293 cases (15.6%); Salmonella spp., 262 cases (13.9%); Shigella spp., 235 cases (12.5%); Aeromonas sobria, 93 cases (4.9%); V. cholerae non-O1, 69 cases (3.7%). 2) The enteropathogenic bacteria were isolated through out the year without any seasonal variation. 3) The major regions where the travellers were infected with the pathogens are as follows: V. cholerae non-O1 (NAG Vibrio) and enteropathogenic Escherichia coli, South-East and South-West Asia; Vibrio other than NAG, South-East and East Asia; Shigella, widely distributed but especially in India; P. shigelloides and Salmonella, widely distributed. 4) 2 strains of toxigenic (cholera toxin-producing) V. cholerae O139 were isolated from patients who had visited Indonesia and Thailand, respectively. 5) In 320 cases (17%), plural enteropathogenic bacteria were isolated from single patients, suggesting a high frequency of the mixed infections. 6) Among Shigella strains, S. sonnei were isolated the most, followed by S. flexneri (24.7%), S. boydii (8.8%) and S. dysenteriae (2.9%). 7) Among Salmonella serovers, Salmonella Enteritidis was isolated the most frequently (39 cases, 14.1%). 8) 218 (91.6%) of 238 Shigella strains and 103 (37.6%) of 276 Salmonella strains were resistant to one or more drugs tested (SM.CP.TC.KM.ABPC.NA.OFLX). 9) All of the 22 V. cholerae O1 strains were Ogawa, E1 Tor. Among them, 19 were toxigenic strains and 3 were non-toxigenic. 10) O4:K8 was the most frequently isolated serover of V. paraemolyticus. 87.4% of all V. parahaemolyticus strains were positive with thermostable direct hemolysin (TDH) gene, and 12.6% of them were positive with TDH-related hemolysin (TRH) gene by DNA-probe methods.

Diarrhea↗
PubMed1996

Voicing distinction in esophageal speech.

In order to analyze the articulatory ability of skilled esophageal speakers in terms of the voicing distinction in consonants, perceptual, acoustical and physiological studies were conducted. It was found that voiced-voiceless confusion was only 10.5% on average in the present subjects. Acoustical analysis indicated that voice onset time (VOT) values in word-initial position and the presence or absence of voicing in word-medial position were most important cues for the voicing distinction of consonants in esophageal speech. Fiber-optic and photoglottographic examinations revealed that there was a transient opening of the neoglottis for the production of voiceless sounds, while it stayed closed for voiced sounds. Immediately before the period of voicelessness, surface EMG obtained from the anterior neck appeared to show transient activation. There was a tendency that peak intraoral pressure values for the voiceless stops were significantly higher in the esophageal speakers than in the normal subject, whereas the values for voiced cognates were rather close to those of the normal.

Aged↗
PubMed1996

Ultrastructure of the lamina propria of the human vocal fold.

We studied three-dimensional arrangement of collagen fibers and elastic fibers in the human vocal fold by scanning electron microscopy after digesting cellular elements and collagen fibers with formic acid treatment and cellular elements and elastic fibers with 10% sodium hydroxide. The superficial layer consisted of clusters of collagen fibers and fine elastic fibers running straight or coiled. The intermediate layer consisted of thick bundles of collagen and elastic fibers running longitudinally and fine coiled elastic fibers. The deep layer consisted of coil elastic fibers and dense collagen bundles. Collagen fibers may have a role of maintaining the organization of vocal folds even during vibration, and elastic fibers act to rapidly restore the vocal folds to their original form. We also studied the distribution of oxytalan fibers in vocal folds by aldehyde-fucusin staining. Oxytalan fibers were distributed throughout the connective tissue of the vocal folds, and a large number of fibers was present just under the epithelial basement membrane and around the muscle fibers. If these fibers are damaged and lose their functions, vibration of the vocal folds will be impaired.

Aged↗
PubMed1996

[Postoperative swallowing function in tongue and oral floor cancer patients reconstructed with a recto-abdominal myocutaneous free flap after glossectomy--quantitative assessment of reconstructed tissue movement].

We examined the postoperative swallowing function of 12 tongue and oral floor cancer patients reconstructed with a recto-abdominal myocutaneous free flap after glossectomy. On the basis of the resection site, the present cases were classified into either anterior type or lateral type. Subjective evaluation of postoperative swallowing function was obtained from self-reports from patients. The movement of the reconstructed tissue was evaluated videofluorographically during swallowing, by tracking the movement of two small pellets temporarily attached to the anterior and central portions of the reconstructed tongue. The trajectory of the two pellets and the selected point of the hyoid bone were recorded together with the distance between the plate and the tongue dorsum, and between the posterior pharyngeal wall and the tongue base. Using a personal computer, a quantitative study of the video images was performed. The results were summarized as follows. 1) The movement pattern of the reconstructed tissue was generally saccadic rather than smooth. It was suggested that the swallowing pattern of the patients was different to that of normal controls. 2) Postoperative swallowing function was poorer in cases of the anterior type when compared to the lateral type. 3) In general, cases which showed relatively wide movement range appeared to achieve subjectively satisfactory swallowing function.

Adult↗