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Biomedical subjects

Y Chiba

Publications and source records attributed to Y Chiba.

At least 127 records · Page 7Linked to original sources
PubMed1997

Studies on the site of renal tubular defect in Bartter's syndrome.

Renal tubular function was studied in an 8-month-old male infant with Bartter's syndrome, which is characterized by hypokalemic metabolic alkalosis, normotensive hyperreninemic hyperaldosteronism, and reduced pressor response to angiotensin II. Chloride transport along the diluting segment (CH2O/CH2O + CCl) was impaired. Furthermore, furosemide did not elicit normal natriuresis, which suggested impaired chloride reabsorptive capacity at the furosemide-sensitive ascending limb of Henle's loop. Loss of antidiuretic hormone-mediated urinary concentration was in support of this. These findings pointed to the thick ascending limb of Henle's loop as the site of the primary defect in this child.

Bartter Syndrome↗
PubMed1997

A model system for convenient fluorescent labeling of sugar chain in taka-amylase A.

A convenient detection of sugar chains in Taka-amylase A (TAA) was done by using 40 micrograms of enzyme, where a decrease in the UV absorption of NaIO4 during the periodate oxidation reaction was monitored. The periodate-oxidized sugar chain was labeled with a fluorescent reagent, N-1-ethylenediaminonaphthalene (EDAN), by incubation at pH 9.5 and 30 degrees C for 1 h. The excess EDAN was removed by either quenching with o-phthaladehyde or Bio-Gel P-2 gel adsorption. Among the peptide fragments prepared from the EDAN-labeled TAA, a fluorescent peptide corresponding to the sugar chain was distinguished by the ODS column. These results suggest that periodate oxidation and subsequent fluorescent labeling were useful for the sensitive analysis of various glycoprotein samples.

Carbohydrates↗
PubMed1997

Lipid peroxidation in linoleic acid micelles caused by H2O2 in the presence of myoglobin.

We investigated the lipid peroxidation in linoleic acid micells caused by H2O2 in the presence of metmyoglobin by monitoring the oxygen consumption. O2 consumption usually consisted of two phases. In the first phase, it occurred slowly and linearly until the concentration of linoleic acid hydroperoxide reached a certain value, rapid consumption, presumably by a chain reaction, then followed in the second phase. No effects of diethylenetriaminepentaacetic acid (DTPA) on the induction period (the period during the first phase) and the maximum oxygen consumption rate (MOCR) in the second phase indicate that free ferric ions liberated from myoglobin had no role in any phases during the lipid peroxidation. The differing dose effects of ascorbic acid, alpha-tocopherol, and sodium nitrite on the induction period and MOCR reflect their respective antioxidative mechanisms during lipid peroxidation.

Antioxidants↗
PubMed1997

[Laparoscopic investigation of 74 cases of nonpalpable testis].

BACKGROUND: The objective of this study is to evaluate the results and advantages of laparoscopic investigation of nonpalpable testis. METHOD: Since March 1986 to May 1996, we performed laparoscopy to investigate 88 nonpalpable testes of 74 cases under general anesthesia. On condition that testis was found intraabdominally, orchiectomy or orchiopexy was performed subsequently. With a finding of vas deferens and/or spermatic vessels entering into internal ring, inguinal canal was explored surgically. If both vas deferens and spermatic vessels were absent or blind-ending intraabdominally, no further examination was performed with a diagnosis of vanishing testis. RESULTS: Location of testes found in this study were as follows. Twenty three (26.1%) testes were found intraabdominally, 36 (40.9%) were intracanalicularly, 13 (14.8%) were distal to external inguinal ring, and 16 (18.2%) were vanishing testes. To those 39 (44.3%) intraabdominal and vanishing cases did not need inguinal exploration. CONCLUSION: In conclusion, a laparoscopic examination for nonpalpable testis is the most effective and less invasive procedure to make sure or preclude the location of the gonad. And in 18% of those who were enrolled in this study, no further surgical interventions were needed. An accurate locating of nonpalpable testis permits site-specific planning of surgical management.

Adolescent↗
PubMed1997

[A simple device of chest wall reconstruction].

We devised a simple method of chest wall reconstruction in two cases of malignant tumor of the chest. We strained a suture (adsorbable or monofilament) to the intact ribs above and below the defect and fixed the sheets of Marlex mesh in double layers and closed the skin without any myocutaneous flap. The postoperative course was uneventful. This device is simple and effective method to maintain the stability of the chest wall defect.

Aged↗
PubMed1996

Effects of intraaortic balloon pumping on septal arterial blood flow velocity waveform during severe left main coronary artery stenosis.

OBJECTIVES: We sought to evaluate the effect of intraaortic balloon pumping on the phasic blood velocity waveform into myocardium with severe coronary artery stenosis. BACKGROUND: In the presence of severe coronary artery stenosis, it is not clear whether intraaortic balloon pumping augments intramyocardial inflow during diastole or changes systolic retrograde blood flow from the myocardium to the extramural coronary arteries. METHODS: Using anesthetized open chest dogs (n=7), we introduced severe stenosis in the left main coronary artery to reduce the poststenotic pressure to approximately 60 mm Hg (>90% diameter stenosis). Septal arterial blood flow velocities were measured with a 20-MHz, 80-channel ultrasound pulsed Doppler velocimeter. Left anterior descending arterial flow, aortic pressure and poststenotic distal coronary pressure were measured simultaneously. The diastolic anterograde flow integral and systolic retrograde flow integral were compared in the presence and absence of intraaortic balloon pumping. RESULTS: Although intraaortic balloon pumping augmented diastolic aortic pressure, this pressure increase was not effectively transmitted through stenosis. Septal arterial diastolic flow velocity was not augmented, and left anterior descending arterial flow was unchanged during intraaortic balloon pumping. CONCLUSIONS: In the presence of severe coronary artery stenosis, intraaortic balloon pumping failed to increase diastolic inflow in the myocardium and did not enhance systolic retrograde flow from the myocardium to the extramural coronary artery. Thus, the major effect of intraaortic balloon pumping on the ischemic heart with severe coronary artery stenosis may be achieved by reducing oxygen demand by systolic unloading.

Analysis of Variance↗
PubMed1996

Influence of pulmonary arterial pressure during flushing on lung preservation.

The effect of changing pulmonary artery pressure during flushing (flushing pressure) on lung preservation was examined in an ex vivo rabbit lung perfusion model. Both lungs were flushed in situ with 200 ml of a preservation solution (extracellular fluid [ECF] type) at 8 degrees C, at a constant flushing pressure maintained by regulating the flushing flow rate from 20 to 120 ml/min. In the controls, the flushing pressure was maintained at 15 mmHg and the lungs were assessed without storage. In the other 5 groups (n = 7 in each group), the lungs were flushed at pressures of 5, 10, 15, 20, and 25 mmHg, respectively. The heart-lung block was then harvested, and immersed in the same solution at 8 degrees C for 24 hr. After 24 hr of storage, the block was reperfused with pooled venous blood for 10 min, and then with oxygenated blood for another 60 min in a closed circuit. Assessment of lung function included blood gas analysis of effluent blood, pulmonary artery pressure, airway pressure, wet:dry weight ratio, and histologic study. At flushing pressures of 5, 20, and 25 mmHg, uniform and clear flushing out of the pulmonary vascular beds was not obtained, resulting in postperfusion pulmonary hypofunction and a high incidence of pulmonary edema. However, at flushing pressures of 10-15 mmHg, we succeeded in completely flushing out the pulmonary vascular beds, and managed to preserve good pulmonary function. In conclusion, we determined the optimal flushing pressure for rabbit lung preservation to be 10-15 mmHg.

Animals↗
PubMed1996

Intracranial extension of paranasal sinus mucocele: two case reports.

In two cases intracranial extension of mucoceles of the paranasal sinus was safely removed by intranasal evacuation and drainage of the lesions located in the paranasal sinus. The diagnosis was ascertained in both cases via intranasal approach. In addition, the volume of the intracranial lesions was reduced. This procedure is both effective and a less invasive diagnostic treatment for the lesion.

Adolescent↗
PubMed1996

Abnormal modulation of cholinergic neurotransmission by opioid in hyperresponsive bronchus of rats.

1. The electrical field stimulation (EFS)-induced bronchoconstriction in vitro in rats challenged by DNP-Ascaris antigen was significantly greater than that in normal rats. 2. Morphine inhibited the EFS-induced bronchoconstriction in normal rats. Whereas the inhibition of EFS-induced bronchoconstriction by the opioid was little, if any, in the DNP-Ascaris-challenged rats. 3. These findings suggest that dysfunction of presynaptic inhibitory modulation through the opioid receptor may take place in the airways of DNP-Ascaris-challenged rats.

Acetylcholine↗
PubMed1996

Surgical treatment of infected thoracic and abdominal aortic aneurysms.

Twelve patients with infected aneurysms of the thoracic and abdominal aorta were evaluated. Aneurysmal location, aetiology, bacteriology and treatment modality were analysed to determine the relationship between these factors and outcome. Patients were divided into two groups based on the preoperative states of their infections. Group 1 patients (n = 7) underwent resection after resolution of their active infection. The causative organisms included Staphylococcus epidermidis (two cases). Salmonella spp. (one). Acinetobacter (one), Mycobacterium tuberculosis (one) and unknown organisms (two). Group 2 patients (n = 5) required urgent surgery because of uncontrolled sepsis despite intensive treatment with antibiotics. The causative organisms included Staphylococcus aureus (two cases). Pseudomonas aeruginosa (two) and Salmonella spp. (one). In group 1, three patients underwent closed en bloc excision of the aneurysm with in-situ graft replacement, and four underwent partial resection with in-situ graft replacement. In group 2, three patients underwent resection of the aneurysm with ligation of aorta and extra-anatomic bypass, and two underwent in-situ graft replacement after débridement of infected tissue. Overall, patients in group 1 had a mortality rate of 14% compared with 80% in group 2. These results suggest that the operative approach and method chosen to restore arterial continuity have less of an impact on outcome. The primary determinants of outcome are virulence of the infecting organism and the preoperative state of the infection.

Acinetobacter Infections↗
PubMed1996

Leukocyte and platelet depletion with a blood cell separator: effects on lung injury after cardiac surgery with cardiopulmonary bypass.

This study was undertaken to assess the effects of leukocyte and platelet depletion on postoperative lung injury in 42 patients who underwent heart operations. Blood was serially sampled before, during, and after cardiopulmonary bypass, and leukocyte count, platelet count, and thromboxane B2 6-keto-PGF1 alpha, leukocyte elastase, thrombin-antithrombin III complex, and D-dimer levels were determined. Postoperative respiratory function was assessed based on analyses of oxygenation and carbon dioxide elimination. Leukocyte and platelet depletion was performed in 21 patients (experimental group) but not in another (control group). In the experimental group, leukocytes and platelets were removed continuously by means of the blood cell separator CS-3000, beginning immediately after the start of the operation and ending 1 hour after the release of aortic occlusion. Leukocyte elastase, thromboxane B2, ratio of thromboxane B2 to 6-keto-PGF1 alpha, thrombin-antithrombin III complex, and D-dimer were significantly lower in the experimental group than in the control group. Of the various indexes of oxygenation, arterial oxygen tension was significantly higher in the experimental group and the alveolar-arterial oxygen pressure difference and respiratory index were significantly lower in the experimental group. The positive end-expiratory pressure needed to achieve an appropriate arterial oxygen tension was significantly lower in the experimental group. The elimination of carbon dioxide was lower in the experimental group. Depletion of leukocytes and platelets reduced respiratory dysfunction after heart operations with cardiopulmonary bypass. It was particularly effective in patients with a low preoperative oxygenation capacity and in those for whom an extended period of cardiopulmonary bypass was required.

6-Ketoprostaglandin F1 alpha↗
PubMed1996

Genomic imprinting of human p57KIP2 and its reduced expression in Wilms' tumors.

p57KIP2 is a potent tight-binding inhibitor of several G1 cyclin complexes, and is a negative regulator of cell proliferation. The gene encoding human p57KIP2 is located on chromosome 11p15.5, a region implicated in both sporadic cancers and Beckwith-Wiedemann syndrome (BWS), a cancer syndrome, making it a tumor suppressor candidate. Several types of childhood tumors including Wilms' tumor, adrenocortical carcinoma and rhabdomyosarcoma display a specific loss of maternal 11p15 alleles, suggesting that genomic imprinting plays an important part. Genetic analysis of the familial BWS has indicated maternal carriers and suggested a role in genomic imprinting. Previously, we demonstrated that p57KIP2 is imprinted in the mouse. Here we describe the genomic imprinting of human p57KIP2 and the reduction of its expression in Wilms' tumors. High resolution mapping locates p57KIP2 in the region responsible for both tumor suppressivity and BWS.

Alleles↗
PubMed1996

Cosmetic reconstruction after mastoidectomy for the transpetrosal-presigmoid approach: technical note.

OBJECTIVE: We describe the technique of cosmetic reconstruction after mastoidectomy in the transpetrosal-presigmoid approach for petroclival lesions. TECHNIQUES: This technique involves raising a single temporo-occipital bone flap and cosmetic mastoidectomy, removing the mastoid bone fragments (by means of a rongeur instead of an air drill) for later reconstruction. Replacement of the bone fragments mixed with fibrin glue enables tamponade against the dura to be achieved without a fat graft. RESULTS: Computed tomographic scans and plain cranial films taken a few years later showed successful reconstruction of the mastoid bone with a good appearance of the retromastoid area in seven patients who underwent this procedure. The only complication was infection in one patient from cerebrospinal fluid leakage from the wound. CONCLUSION: We have developed a simple and easy technique of cosmetic reconstruction after the transpetrosal-presigmoid approach.

Bone Transplantation↗
PubMed1996

A newly identified exonic mutation of the WT1 gene in a patient with Denys-Drash syndrome.

An 11 month old boy with hypospadias and bilateral undescended testes developed renal failure. Denys-Drash syndrome was suspected and molecular analysis of the WT1 gene was performed, although no Wilms' tumor was identified. Direct sequencing analysis of genomic DNA from this patient revealed a G to A transition resulting in 366Arg to Leu substitution in exon 8 which has hitherto not been described. This newly identified mutation will help in the understanding of functional domains and in making a diagnosis of Denys-Drash syndrome.

DNA Mutational Analysis↗
PubMed1996

Evaluation of intramyocardial coronary blood flow waveform during intraaortic balloon pumping in the absence or presence of coronary stenosis.

Our aim was to evaluate the effects of intraaortic balloon pumping (IABP) on the blood velocity waveform in the absence or presence of coronary artery stenosis. Using anesthetized open-chest dogs, the septal arterial blood flow velocities were measured with a 20 MHz 80-channel ultrasound pulsed Doppler velocimeter in the absence (n = 5) or presence (n = 3) of left main coronary artery stenosis. The blood velocity waveform was analyzed by calculating the systolic retrograde velocity integral (SR) and the diastolic antegrade velocity integral (DA). A slosh ratio was defined as SR/DA. The left anterior descending arterial flow (CBF), aortic pressure (AoP), and poststenotic distal coronary pressure (DiP) were also measured simultaneously. We compared the effect of IABP on the velocity waveforms in the absence and in the presence of coronary artery stenosis. In the absence of stenosis, IABP increased DiP during diastole and augmented DA while it also increased SR. IABP augmented the net CBF because of the greater increase in DA than SR. In the presence of stenosis, however, IABP did not increase DiP and resulted in no significant effect on the net CBF.

Animals↗
PubMed1996

An epitope chimeric antigen for the hepatitis C virus serological screening test.

The epitope chimeric antigen, CepCM, composed of the 9 selected major epitope regions (two in NS3, two each in the NS4 of two genotypes, two each in the core of two genotype, and one in the core in hepatitis C virus (HCV) polypeptide), was expressed as a fusion protein of the trpE peptide in E. coli. An ELISA test using this antigen produced the same judgements with most of the panel sera as a second generation HCV screening kit. Though discrepancies were found in twelve samples (5% of the samples), further analysis revealed that eleven samples were indeterminate sera as judged by an immunoblot test. The reactivity found in several seroconversion series sera suggested that CepCM has superior reactivity to HCV infected sera than some second generation kits. These data indicated that an epitope chimeric antigen with a man-made sequence will be a excellent tool for a diagnostic test kit.

Antigens, Viral↗