Search PubMed⌕ Search

Biomedical subjects

Y Maeda

Publications and source records attributed to Y Maeda.

At least 775 records · Page 43Linked to original sources
PubMed1989

Change in solubility of insulin in therapeutic mixtures of insulin preparations: HPLC analysis.

We systematically and quantitatively observed the changes in solubility when short- and intermediate-acting insulin preparations were mixed together, using high-performance liquid chromatography (HPLC) and centrifugation. We tested 30 combinations of 16 kinds of commercial insulin preparations, including six short-acting and eight intermediate-acting preparations. The soluble insulin component in the short-acting preparations examined was in all cases insolubilized to various extents after mixing. Particularly remarkable was the complete precipitation of the insulin from Actrapid Human when it was mixed with Monotard Human (1:1). This sort of drastic change in insulin solubility after mixture was reflected in the changes in blood glucose level after the subcutaneous injection of the mixture to rabbits. The information provided by pharmaceutical companies on absorption kinetics and action profiles of short-acting insulin preparations may no longer be valid when mixtures with longer-acting preparations are used.

Animals↗
PubMed1989

Angiomyoma of the upper lip: report of a case with electron microscopic and immunohistochemical observation.

Immunohistochemical and electron microscopic observations of a vascular leiomyoma of the upper lip are presented. Tumour cells were positive for desmin, vimentin and neuron specific enolase but not for S-100 protein. Factor VIII was detected in the endothelium of blood vessels. Ultramicroscopically, the spindle-shaped tumour cells had elongated nuclei and cytoplasm containing abundant myofilaments and pinocytotic vesicles. Emphasis is placed on the fact that an immunohistochemical approach using appropriate antibodies can be used in identifying this tumour.

Adult↗
PubMed1989

Kinetic study of the effects of solvation on the dimerization process of alpha-chymotrypsin.

The dimeric association process of alpha-chymotrypsin has been studied with the aid of a stopped-flow spectrophotometer at various temperatures and pH values. From the temperature dependences of the forward reaction rate constant (kf) and the equilibrium dimerization constant (KD), the reaction system observed here is concluded to be entropy-driven. The increase in entropy can be attributed to the release of water molecules from both the active site and the surface part of the protein molecule during the course of dimerization. From the pH dependences of the reaction rate constants and the equilibrium constant, the reaction is concluded to depend strongly on the dissociations of the site between the carboxyl group of the aspartic acid and imidazolyl group of the histidine residues (in the higher pH region), and the site between the imidazolyl group of the histidine and the carboxyl group of the tyrosine residue (in the lower pH region), respectively.

Chymotrypsin↗
PubMed1989

Prevention of transmission of human T-lymphotropic virus type 1 (HTLV-1) through transfusion, by donor screening with antibody to the virus. One-year experience.

To prevent the transmission of human T-lymphotropic virus, type 1 (HTLV-1) during blood transfusion, a program was implemented to screen donors for antibodies to the virus, using a newly developed, passive agglutination (PA) method. During the period April 1986 to March 1987, 675 recipients of donor blood in whom the antibody to HTLV-1 was not present before transfusion were followed for at least 50 days after transfusion. One of these 675 seroconverted despite the transfusion of screened blood, but this seroconversion rate (0.15%) represents a marked decrease from the rate of 8.3 percent prevalent before donor screening began. The rate in the Fukuoka area of donors seropositive for anti-HTLV-1 is 5.34 percent, as detected by the PA method and 1.80 percent, as assessed by the indirect immunofluorescence (IF) technique, with PA-positive but IF-negative blood units thus accounting for 3.5 percent (5.34-1.80) of the total blood donated. The seroconversion rate among recipients transfused with blood screened by IF (at Kyushu University Hospital only) from 1981 to 1985 was 0.41 percent, which was not significantly different from the rate of 0.15 percent observed after PA screening. The discrepancy between PA and IF in the rate of seropositivity was due, in part, to the higher sensitivity of PA in detecting anti-HTLV-1. It is proposed that all donor blood in areas where HTLV-1 is endemic be screened by PA before transfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Agglutination Tests↗
PubMed1989

A neutralizing epitope of human immunodeficiency virus type 1 has homologous amino acid sequences with the active site of inter-alpha-trypsin inhibitor.

A neutralizing epitope (epitope beta) of the HTLV-IIIB strain of HIV-1 was mapped to 24 amino acids of an external envelope glycoprotein (gp120) using a neutralizing monoclonal antibody (0.5 beta) and hetero-antisera against synthetic peptides encoding gp120. Proteins that have homologous sequences with epitope beta were sought from a databank of protein sequences to assess biological features of epitope beta. The results showed that epitope beta was found to have homologous sequences to inter-alpha-trypsin inhibitor (ITI). The homologous region of ITI included the active site of the protein. Synthesized peptides including epitope beta were good substrates for trypsin, because these peptides inhibited trypsin activities in a competitive manner (Ki = 24.5 microM). Human urinary trypsin inhibitor (UTI), a protein indistinguishable from ITI, as well as synthetic peptides including epitope beta inhibited syncytium formation caused by the LAV-1-infected CCRF-CEM and uninfected Molt-4 cells in a dose-dependent manner (0.1-1 mM). These findings suggest that epitope beta of HIV-1 could be substrate of protease upon HIV-1 infection and also suggest that protease inhibitory activity of epitope beta may play a role in the pathophysiology of HIV-1-infected individuals.

Alpha-Globulins↗
PubMed1989

Performance certification of gelatin particle agglutination assay for anti-HTLV-1 antibody: inconclusive positive results.

In order to test the performance of particle agglutination assay (PA), 800 preselected PA-positive sera at 8 blood centers in the Kyushu area were tested in various assays. Most blood centers should improve their PA technique, since a third of the samples were PA-negative in our hands. A third of our PA high-titer sera were negative in indirect immunofluorescence and enzyme immunoassay, the results of which were consistent with each other. Western blots did not detect every positive serum. PA inhibition positivity was not consistent with PA titer. Most IgM antibody-positive sera also contained IgG antibody. PA should be used in combination with other methods before notifying the results to positive testees.

Agglutination Tests↗
PubMed1989

Transition of starving Dictyostelium cells to differentiation phase at a particular position of the cell cycle.

The relationship between proliferation and differentiation in Dictyostelium discoideum Ax-2 was analyzed with reference to the cell-cycle position at the onset of starvation, using cells synchronized by temperature shift (11.5 degrees C-22.0 degrees C). To examine how far Ax-2 cells at any particular phase of the cell cycle are able to progress through the cycle in response to nutritional deprivation, we measured temporal changes in cell number and nuclearity after starvation. Nuclear DNA synthesis in synchronously developing cells was also monitored by pulse-labeling with [methyl-3H]thymidine. Increase in cell number and subsequent DNA synthesis occurred in cells just before mitosis (referred to as T0.5 cells and T1 cells; 0.5 h and 1 h after the shift-up from 11.5 degrees C to 22.0 degrees C respectively), but not in T3, T5, or T7 cells. When T1 cells were incubated for 6 h in the absence of external nutrients, they (T1 + 6 cells) exhibited developmental features similar to T7 cells, which most rapidly acquired chemotactic sensitivity to 3',5'-cyclic adenosine monophosphate (cAMP) and EDTA-resistant cohesiveness after starvation. Thus, it is quite likely that Ax-2 cells may progress through the cell cycle to a particular point (possibly the cell-cycle position of T7 cells), irrespective of the presence or absence of nutrients, and enter the differentiation phase from this point under conditions of nutritional deprivation. There was no difference in the ratio of prestalk to prespore cells in migratory pseudoplasmodia derived from cells that had been starved at other cell-cycle positions.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Cycle↗
PubMed1989

Developmental retardation in children with refractory epilepsy.

It is controversial whether developmental retardation occurs in children with epilepsy and what causes the retardation if it occurs. The present study aims to reveal the factors associated with the retardation. The patients were 126 children who had been developmentally normal before the onset of epilepsy and had been followed for more than five years. Forty-eight of the 126 children showed mental retardation, and the remaining 78 had normal mental development at the follow-up. Developmental retardation was observed in children with onset before one year, known etiology, diffuse slow spike-wave or hypsarrhythmia on EEG, ingestion of six or more drugs and high blood levels of phenobarbital or phenytoin. Late onset of epilepsy, idiopathic or familial etiology, ingestion of five drugs or less and low blood level of phenobarbital or phenytoin were associated with normal development.

Adolescent↗
PubMed1989

Immunohistochemical and histologic study of cervical lymphoepithelial cysts.

Four cases of lateral cervical cysts were reported. All cyst walls were lined with keratinized stratified squamous epithelium, and contained lymph follicles with well-defined germinal centers. Ectopic salivary gland tissue was found in one case. Histochemical examination by the immunoperoxidase method revealed the existence of carcinoembryonic antigen (CEA). However, alpha-feto protein (AFP) and amylase were not detected in any of the cysts. The cyst fluid contained high levels of CEA and high titers of salivary type amylase, but AFP was negative. These results do not support any one of the theories concerning the etiology of cervical lymphoepithelial cysts. It seems likely that cysts derive from both epithelial remnants of the branchial apparatus and from salivary gland inclusions in lymph nodes.

Adolescent↗
PubMed1989

Biosynthesis of leukotrienes in canine cerebral vasospasm.

We produced cerebral vasospasm in 29 dogs by the "two-hemorrhage" method of intracisternal injections, 2 days apart, of autogenous arterial blood. Leukotriene (LT) C4, LTD4, and LTE4 were purified from incubated basilar artery, medulla oblongata, hypothalamus, median eminence, and blood clot from around the basilar artery using reverse-phase high-performance liquid chromatography, and the amount of each LT was quantified separately by bioassay with guinea pig ileum. The biosynthetic capacity for total LTs was approximately three times higher in the hypothalamus and median eminence than in the basilar artery and medulla oblongata in the eight normal dogs. In the dogs with subarachnoid hemorrhage, the biosynthetic capacity was increased significantly both before and 2 hours after the second injection of blood on Day 2 and was normal on Day 7 in the basilar artery and medulla oblongata, whereas the biosynthetic capacity was decreased significantly 2 hours after the first and second injections of blood and was increased significantly on Day 7 in the hypothalamus and median eminence. In blood clot the biosynthetic capacity was increased continuously after the first injection of blood. Thus, the biosynthetic capacity for total LTs showed a time- and tissue-specific change after subarachnoid hemorrhage.

Animals↗
PubMed1989

Finite element method simulation of bone resorption beneath a complete denture.

Bone resorption beneath a maxillary complete denture was simulated by the finite element method, assuming that a threshold of compressive strain exists in the alveolar bone above which the resorption occurred. The pattern of predicted resorption was observed when 100 N of force was applied to three positions occlusally, and 20 N was applied facially. Moreover, we observed the effect of rebasing the denture after initial resorption. The results indicate that resorption was initiated on the facial and occlusal surfaces of the alveolar ridge and proceeded palatally. The resorption was greater as the occlusal load point moved facially and when the force was applied in the facial direction. When the load point was toward the facial, rebasing the denture accentuated the resorption, but when the load point was toward the palatal, the resorption was almost the same regardless of rebase. The pattern of simulated bone resorption was similar to that reported from clinical observations, which suggests that the resorption may be associated with compressive strains developed in the alveolar bone. The results argue for the importance of occlusal adjustment of dentures to move the occlusal load point palatally and produce balanced occlusion in protrusion and lateral excursions, especially after a rebase procedure.

Alveolar Process↗
PubMed1989

The rapid evaluation of intestinal bacterial growth using a conjugate of ursodeoxycholic acid with para-aminobenzoic acid.

From the standpoint of utilizing the distinctive feature of para-aminobenzoic acid (PABA) and the metabolism of intestinal bile acid, a conjugate of ursodeoxycholic acid with PABA (PABA-UDCA) was newly synthesized to study whether it can be a good material or not for the evaluation of the activity of intestinal bacterial growth. This compound was efficiently deconjugated in an incubation experiment with cholylglycine hydrolase resulting in the release of PABA. In a cultivation experiment, this compound was deconjugated by the same species of aerobic and anaerobic bacteria that deconjugated glycocholic acid. In an animal experiment, urinary excretions of PABA during 6 h following oral administration of 10 mg PABA-UDCA were determined. The control rat (n = 10) excreted 338.5 +/- 13.8 micrograms (mean +/- S.E.) of PABA. In contrast with this, the rats (n = 10) with intestinal antisepsis by the administration of polymyxin B and tinidazole excreted less PABA (14.0 +/- 2.5 micrograms; p less than 0.001), whereas the rats with intestinal bacterial overgrowth owing to the artificially made enteric blind loop excreted more PABA than the control rats did (673.6 +/- 70.2 micrograms; p less than 0.01). These observations indicate that this new compound is likely to offer a simple and rapid method for evaluation of intestinal bacterial growth.

4-Aminobenzoic Acid↗
PubMed1989

Hydrolysis and absorption of a conjugate of ursodeoxycholic acid with para-aminobenzoic acid.

Hydrolysis of ursodeoxycholyl-p-aminobenzoic acid (PABA-UDCA), a synthetic bile acid conjugate used for the evaluation of the activity of intestinal bacterial growth, was studied with pancreatic enzymes, carboxypeptidase A, carboxypeptidase B, trypsin alpha-chymotrypsin, cholylglycine hydrolase, liver homogenate, small intestinal homogenates, and plasma, in comparison with the hydrolysis of glycocholic acid, ursodeoxycholyl-L-leucine (L-Leu-UDCA), and ursodeoxycholyl-L-lysine (L-Lys-UDCA). PABA-UDCA was specifically cleaved by bacterial cholylglycine hydrolase to ursodeoxycholic acid and para-aminobenzoic acid (PABA), but not by pancreatic enzymes. L-Leu-UDCA was cleaved by pancreatic enzymes, carboxypeptidase A, and cholylglycine hydrolase. L-Lys-UDCA was cleaved by pancreatic enzymes, carboxypeptidase B, and cholylglycine hydrolase. The small amount of glycocholic acid was cleaved by pancreatic enzymes and carboxypeptidase A and B, and cholylglycine hydrolase hydrolyzed glycocholic acid completely. In everted gut sac experiments, PABA-UDCA was absorbed by active transport in the rat terminal ileum, and the same rate of PABA was absorbed by passive diffusion in the four segments of the rat small intestine. These observations indicate that PABA-UDCA test can evaluate the activity of small intestinal bacterial growth.

4-Aminobenzoic Acid↗
PubMed1989

[Traumatic occlusion of the extracranial internal carotid artery. Report of two cases].

Two cases of tapered occlusion of the unilateral internal carotid artery after head and facial injury are reported. The first was a 42-year-old male admitted because of left hemiparesis 3 hours after receiving blows to the face. Computed tomography (CT) scan obtained 10 hours after injury showed an area of slight low density in the right frontotemporal region. Carotid angiography demonstrated tapered occlusion of the right cervical internal carotid artery. A large cerebral infarction had developed in the right hemisphere and the patient died 10 days after the traumatic incident. The second case involved a 45-year-old male hospitalized with aphasia and right hemiparesis about 1 month after incurring a depressed fracture of the left temporal bone. CT revealed two small low-density areas in the left corona radiata, and carotid angiography disclosed tapered occlusion of the left cervical internal carotid artery. The neurological signs gradually improved after anticoagulant therapy. Early diagnosis of traumatic cervical carotid artery occlusion may be difficult in the absence of apparent cervical trauma with focal cerebral symptoms appearing after a lucid interval. No definitive management has been established and the prognosis is poor. It is emphasized that unusual neurological symptoms following head or cervical trauma should provoke suspicion of carotid artery injury, which, on diagnosis, should be promptly treated.

Adult↗
PubMed1989

[Recurrent cerebral aneurysm suggestive of misplaced clipping. Case report].

A case of recurrent cerebral aneurysm after complete neck clipping is described. A 47-year-old male who presented with headache and nausea underwent neck clipping of a berry aneurysm of the left middle cerebral artery. Ten days later, angiographic findings suggested the presence of a second, large aneurysm adjacent to the first, which suggested misplaced clipping. Reoperation confirmed that a new aneurysm had formed next to the original aneurysm. A possible explanation of the recurrence is as follows. The M1 flowed into the M2 at a right angle. The aneurysmal neck was situated on the distal end of the M1 and the dome protruded antero-inferiorly at an angle of nearly 90 degrees to the long axis of the M1 opposite the origin of the M2. The parent artery bulged slightly, and its wall was thin and reddish, just distal to the aneurysmal neck. Proximal to the neck there was another small bulge, but the wall here was normal. These bulges were coated with Oxycel and Biobond at the time of aneurysmal neck clipping. After clipping, blood flow into the dome was interrupted, and the consequent hemodynamic stress caused the bulges to expand dramatically and form a new aneurysm. The authors conclude that there is a likelihood of early recurrence after neck clipping if the parent artery exhibits such morphological features as observed in this case.

Cerebral Arteries↗