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Biomedical subjects

H Aoki

Publications and source records attributed to H Aoki.

At least 325 records · Page 18Linked to original sources
PubMed1991

1H-NMR study of the intramolecular interaction of a substrate analogue covalently attached to aspartic acid-101 in lysozyme.

We prepared the lysozyme derivative in which the beta-carboxyl group of Asp101 was modified with alpha-O-methyl N-glycylglucosaminide as an amide by means of the carbodimide reaction (alpha-MGG lysozyme). Since Asp101 residue is located at the edge of the active site cleft, a 1H-NMR study was carried out for this derivative in order to investigate the interaction between the introduced substituent and the active site cleft. It was confirmed that the alpha-MGG moiety sat in the active site cleft in alpha-MGG lysozyme from the reduction of line broadening of the NH-proton of Trp63 located in the active site cleft, the remarkable chemical shift change of the methyl group of the alpha-MGG moiety upon adding a trimer of N-acetyl-D-glucosamine [(NAG)3], and the NOE between the C6-proton resonance of Trp63 and the methyl resonance of the alpha-MGG moiety. Furthermore, alpha-MGG lysozyme had increased thermal stability compared with native lysozyme. Therefore, it was concluded that the alpha-MGG moiety covalently attached to Asp101 interacted with the active site cleft to increase the thermal stability of lysozyme.

Animals↗
PubMed1991

Relationship between auditory brainstem response waveform and head size.

The relationship between the head size and the latency and amplitude of the auditory brainstem response (ABR) was investigated in 60 normal-hearing adults (30 males and 30 females). We found a strong positive correlation between the latency of ABR waves and the head size and a strong negative correlation surfaced between the ABR amplitude and head size. These results indicate that the head size is one of the most important factors influencing the waveform of the ABR.

Adolescent↗
PubMed1991

Effects of hypogastric nerve and sympathetic chain stimulation on the pelvic nerve induced penile erection in the dog.

The effects of electrical stimulation of hypogastric nerve and sympathetic chain on 'electroerection' (penile erection induced by electrical stimulation of the pelvic nerve) were studied in dogs to clarify the physiological roles that these neural inputs may play in producing and/or maintaining penile erection. As an objective parameter of hemodynamics of the penile circulation, the pressure in the corpus cavernosum of the penis was measured. Hypogastric nerve electrostimulation was performed in 24 dogs who had received pelvic nerve stimulation and, therefore, had 'electroerection'. Ten dogs responded to this procedure with an augmentation of 'electroerection', 10 with an attenuation of 'electroerection', and 4 with no appreciable changes. 4 out of the 10 animals who exhibited an attenuation response were then given an alpha 1-adrenergic blocker (prazosin hydrochloride) prior to the electrical stimulation to evaluate the specificity of the effects of the hypogastric nerve stimulation. In 3 of the 4 dogs the attenuation effect was abolished by this treatment and instead an augmentation effect became evident. Sympathetic chain electrostimulation was performed in 6 dogs with 'electroerection'. When applied to the L4-5 interganglionic segment, it produced a biphasic response which consisted of an initial increase followed by a decrease of the intracorporeal pressure. In contrast, stimulation of the L2-3 interganglionic segment produced a monophasic response consisting of only augmentation of the intracorporeal pressure. These data suggested that there might be two groups of fibers in the hypogastric nerve and sympathetic chain which are functioning antagonistically, and that the anti-erectile neural inputs are mediated primarily by the alpha 1-adrenergic system. To examine the sites of penile vasculature where the innervating hypogastric nerve exerts its effects, electrical pelvic/hypogastric nerve stimulations were performed in dogs in whom the inflow blood circulation to the corpora cavernosa was disrupted by arterial ligation and replaced by a constant saline infusion. It appears that the stimulatory input via the hypogastric nerve caused an increased blood flow into the cavernous space due to vasodilation of the inflow blood vessels, and the inhibitory effect occurred mainly due to relaxation of the draining blood vessels with a resultant increase of the blood outflow from the cavernous space.

Animals↗
PubMed1991

[A study of ionized calcium in the whole blood of patients with subarachnoid hemorrhage].

In 14 normal volunteers and 22 consecutive patients with subarachnoid hemorrhage (SAH) due to a ruptured cerebral aneurysm, ionized calcium (Ca2+) concentrations in whole blood were measured using an automatic calcium analyzer. The values were corrected against pH 7.4. The relationships between the Ca2+ concentration and the following aspects were studied: neurological grading by Hunt and Kosnik, grade of SAH on computed tomography scan by Fisher's definition, and the presence of vasospasm. Clinical vasospasm was recognized in eight cases. The averaged Ca2+ value of the control group was 1.23 +/- 0.02 mmol/l. In patients with a poor neurological grade or severe SAH, the Ca2+ level was apt to be lower than that of the control group. In patients with vasospasm, the values of Ca2+ were significantly decreased, especially between 8 and 14 days after SAH, compared with those patients without vasospasm and the control group (p less than 0.05). These results indicate that measurement of Ca2+ concentration in whole blood may give a useful clue to treatment of vasospasm by calcium antagonist and that it may also provide a possible indicator as to the time of vasospasm in patients with severe SAH. However, it is very difficult to conclude whether decreased level of Ca2+ in patients with vasospasm is caused by the vasospasm itself.

Adult↗
PubMed1991

Cloning and nucleotide sequences of the complementary and genomic DNAs for the alkaline protease from Acremonium chrysogenum.

Complementary DNA encoding Ac. chrysogenum alkaline protease (Alp) was isolated from the Ac. chrysogenum ATCC11550 cDNA library by express-blot assay. The genomic DNAs encoding Ac. chrysogenum Alp were isolated from the Ac. chrysogenum genomic DNA library using the cloned cDNA as a probe. The 3150 nucleotides of the gene were sequenced. The prepro-Alp consists of 402 amino acids and two intervening sequences are found within the coding region. The amino acid sequence of Ac. chrysogenum Alp has 57% homology to that of Aspergillus oryzae Alp. The entire cDNA, encoding Ac. chrysogenum Alp, when introducing into the yeast Saccharomyces cerevisiae, directed the secretion of enzymatically active Alp into the culture medium.

Acremonium↗
PubMed1991

The mechanical properties and solubility of strontium-substituted hydroxyapatite.

The mechanical properties and solubility of sintered Sr-substituted hydroxyapatites were examined in order to investigate the influences of Sr incorporation into hydroxyapatite in bones and teeth on them. Hydroxyapatite (HAp), Sr-substituted hydroxyapatite (Ca.SrAp), and strontium-hydroxyapatite (SrAp) were synthesized and sintered. The bending strength and Young's modulus were measured. Also, solubility in isotonic NaCl solution was examined. The Young's modulus of Sr-substituted hydroxyapatite (Sr wt% = 1.0) and hydroxyapatite surface treated with Sr ion were greater than that of hydroxyapatite. The bending strengths of Sr-substituted hydroxyapatites (Sr/Ca = 4/6 and less) were reduced slightly compared to that of hydroxyapatite. The bending strength of hydroxyapatite surface treated with Sr ion was increased compared to that of hydroxyapatite. The solubility in isotonic NaCl solution at 37 degrees C was increased with an increase in Sr content. The effects of Sr on the mechanical properties and solubility of bones and/or teeth are discussed.

Biomechanical Phenomena↗
PubMed1991

[Problems with topical therapies for extensive squamous cell carcinoma of the buttocks].

In patients in whom cancer originating from a bed-sore has advanced to a stage where radical treatment is impossible, topical treatment with ointment, or systemic anti-cancer chemotherapy, is usually applied. We recently attempted treatment of extensive squamous cell carcinoma of the buttocks, for which radical treatment was impossible, by chemotherapy using a reservoir for intraarterial injection. This therapy involved intraarterial injection of bleomycin and 5-FU, together with topical treatment with 5-FU ointment. We describe the problems encountered with this therapy, e.g., measures against fever after intraarterial injection, management of the affected area, evacuation, possibility and limits of radiation therapy, and assessment of its efficacy.

Administration, Topical↗
PubMed1991

[Influence of respiratory frequency in measurement of specific airway conductance during non-panting breathing].

In order to investigate the influence of respiratory frequency in the measurement of specific airway conductance (sGaw) during non-panting breathing, we examined specific airway conductance using a body plethysmograph (BX-82, Minato) in 20 stable pulmonary emphysema patients and 19 normal control subjects. Our body plethysmograph device can measure sGaw automatically without panting by making various corrections using a 16-bit microcomputer. We measured sGaw first at a flow of 0.5 L/sec during both inspiratory and expiratory ventilatory phases, then the respiratory frequency was changed from 0.5 to 1.0, 1.5 and 2.0 Hz. In normal control subjects sGaw, tidal volume and mouth flow significantly changed by increasing respiratory frequency, and there was a significant correlation between sGaw and mouth flow. In pulmonary emphysema patients, tidal volume decreased significantly by increasing respiratory frequency, and there was a significant correlation between sGaw and tidal volume, but sGaw and mouth flow did not change significantly by increasing respiratory frequency. These results suggest that specific airway conductance is influenced by respiratory frequency, possibly due to the change in tidal volume and mouth flow. It is necessary to standardize respiratory frequencies and mouth flows in the measurement of specific airway conductance during non-panting breathing.

Aged↗
PubMed1991

[Immunohistochemical expression of alpha-1-antitrypsin in human gliomas].

The present paper describes the analysis of immunostaining patterns of four antibodies, alpha-1-antitrypsin (alpha-AT), glial fibrillary acid protein (GFAP), S-100 protein (S-100), and vimentin in 31 human gliomas. The gliomas were 10 astrocytomas, 10 anaplastic astrocytomas, and 11 glioblastoma multiforme tumors. The immunoreactivity for vimentin and alpha-AT that is one of the main proteinase inhibitors changed in proportion to the degree of histological malignancy. As alpha-AT was localized mainly in the cytoplasm of tumor cells and partially in extracellular spaces, it was thought to have been derived from tumor cells. Preparations immunolabelled with anti-GFAP and anti-S-100 showed no increasing loss of immunoreactivity parallel with increasing malignancy.

Adolescent↗
PubMed1991

[Industrial standards of hose assemblies for use with medical gas systems: safety against collapsing loads].

We experienced troubles caused by mounting an anesthesia machine and a pump oxygenator on an oxygen pressure-resistant hose that connected the central piping system with the anesthesia machine. Therefore, we measured the resistance of 9 types of hose assemblies to collapsing loads by the method in the International Standardization Organization (ISO) 5359. Two types of hose made in the U.S. were highly resistant. On the other hand, 7 types of domestic hose tended to be obstructed with collapsing loads, and 3 of them did not fulfill ISO's criteria. To prevent anesthetic accidents, improvements in the property of hose assemblies and the establishment of their industrial standardization are urgently needed.

Accident Prevention↗
PubMed1991

[A case of replacement ileocystoplasty for contracted bladder].

The patient was a 49-year-old male. He had a history of asymptomatic hematuria that had occurred 3 years previously. The hematuria and pollakisuria developed again from about March, 1989, and he was hospitalized for bladder tamponade in April. Bilateral percutaneous nephrostomies were performed because a contracted bladder and bilateral hydronephrosis were detected. He was then admitted to our hospital on June 21. The cause of the contracted bladder was not evident, despite extensive examination. A replacement ileocystoplasty constructed by Shishido's method was used to replace the contracted bladder. A U-shape pouch was prepared by detubularization of 25 cm of the ileum and this pouch was anastomosed to the incised end of the bladder neck after subtotal cystectomy. The ureter and ileum were then anastomosed using Coffey's method. The bladder capacity and the maximum urinary flow rate after 1 year were 350 ml and 13 ml/sec, respectively, and residual urine was not noted after urination even following abdominal pressure. Urinary incontinence was not noted either.

Humans↗
PubMed1991

[Cisplatin, doxorubicin and vindesine in the treatment of advanced non-small cell lung cancer].

Thirty-seven patients with advanced non-small cell lung cancer were enrolled to evaluate a combination chemotherapy of cisplatin (80 mg/m2), doxorubicin (30 mg/m2) and vindesine (2 mg/m2 x 3). The overall response rate was 27% with ten partial remission. The median survival of whole patients was 11.4 months. The calculation of median survival of the patients with partial remission has not been completed: nine of ten patients have been still alive during the follow-up period of 4 to 16 months. The survival of the patients with PR was significantly different from those of the patients with NC or PD. The major toxicity was myelosuppression. These results indicate that a combination chemotherapy with cisplatin, doxorubicin and vindesine is a moderately effective regimen against non-small cell lung cancer compared to others.

Adult↗
PubMed1991

[Brain tumors in Yamaguchi Prefecture--incidence through 4 years].

The incidence of brain tumors was studied in Yamaguchi prefecture of about 1,600,000 population. All of the brain tumor patients admitted to the neurosurgical hospitals in Yamaguchi prefecture were registered. Cases of osteoma, lipoma, scalp tumor and spinal tumor were excluded. From 1986 through 1989, 726 cases were registered. 135 recurrent cases were included. Therefore first-diagnosed primary brain tumors were selected to calculate the true incidence. The number of cases of primary brain tumor was 478 and showed female preponderance (male/female: 207/271). The incidence of primary brain tumor was 7.5/100,000/year (male/female: 6.8/8. 1). No difference was present between the incidence in cities and that in rural districts. Percentages of representative tumors were 28.2% for glioma, 32.8% for meningioma, 13.0% for pituitary adenoma and 10.7% for neurinoma. Age-adjusted incidence was 2.1/100,000/year for glioma and 2.1/100,000/year for meningioma. The incidence of glioma was lower and that of meningioma was higher in Yamaguchi prefecture than those in other reports. Compared with the Brain Tumor Registry of Japan (1969-1983), the percentage of meningioma cases was large in Yamaguchi prefecture. This difference owed partly to the increased number of population over age of 40's in Yamaguchi prefecture. The peak of age distribution was present in age of 50's in Yamaguchi prefecture and in age of 30's and 40's in Brain Tumor Registry of Japan. The peak of age distribution shifted to older ages in Yamaguchi and the difference was conspicuous in age of 60's. This peak consisted of mainly cases of meningioma and partly those of glioma.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1991

[Operative results of simultaneous replacement of aortic valve and ascending aorta].

As a surgical treatment of ascending aortic aneurysm with aortic valve regurgitation, we employed Bentall's procedure in 6 cases, Cabrol's procedure in 6 cases, Cabrol's procedure in 3 cases and Carrel patch technique in 2 cases. No hospital mortality was recorded. Late complications were noted in 2 patients. A graft dehiscence of the anastomosis of the right coronary artery occurred in 1 patient with Cabrol's procedure, 3 months postoperatively. In another patient with Bentall's procedure, enlargement of the dissected false lumen at the distal aortic arch necessitated surgical repair in other hospital, 4 years and 4 months after primary repair. All of the surviving patients showed improvement in cardiac function and their clinical status. We have frequently experienced troublesome intraoperative bleeding in applying Bentall's procedure and Cabrol's procedure also. However, hemostatic control was permitted by Cabrol's trick. We are satisfied with the results obtained by Carrel patch technique. This technique facilitates secure coronary anastomosis and definitive hemostasis is attained.

Adult↗
PubMed1991

[Pure red cell aplasia and pseudothrombocytopenia associated with hepatitis A].

We report a rare case who developed pure red cell aplasia (PRCA) and pseudothrombocytopenia associated with hepatitis. A 50-year-old woman was admitted to the hospital because of acute hepatitis A. On the 22nd hospital day, normocytic normochromic anemia without reticulocytosis was developed. A bone marrow aspirate revealed erythroid hypoplasia with a small percentage of proerythroblasts and basophilic erythroblasts, but almost complete absence of polychromatophilic and orthochromic erythroblasts. This case was diagnosed as PRCA characterized by the maturation arrest of erythropoiesis. Anemia was spontaneously recovered following marked reticulocytosis. Afterward, transient EDTA-dependent pseudothrombocytopenia developed for 3 months. The serum taken during the acute phase of clearly inhibited BFU-E colony formation. This data suggests that some humoral factor in the serum of this patient may be involved in the pathogenesis of PRCA.

Female↗