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Biomedical subjects

H Imai

Publications and source records attributed to H Imai.

At least 451 records · Page 25Linked to original sources
PubMed1988

Microvascularization of the free gingival autograft.

Nobuto has previously reported on the initial anastomosis involved in establishing circulation between a free gingival autograft and the recipient bed. This study will present observations on the maturation of new sinusoidal vessels involved in maintaining circulation to the graft and the resulting histovascular organization. Using 56 mongrel dogs, the ongoing processes were observed periodically over 84 days after grafting. For this purpose, vascular corrosion casts were examined with the scanning electron microscope. At the same time, employing both light microscopy and transmission electron microscopy, histopathological and ultrastructural observation on the developing three-dimensional vascular architecture were recorded with supporting photographs. Thus, the entire process from the development of a vascular plexus parallel to the bone surface on the seventh day to the transformation to a vertical dendritic vascular architecture firmly establishing the circulation to the graft by the 84th day, is provided in both descriptive and pictorial detail.

Animals↗
PubMed1988

Ultrastructural changes of subepithelial capillaries following graft epithelialization.

This study investigated architectural changes in the nourishment-providing capillaries beneath the epithelium that accompany graft epithelialization. A total of 77 mongrel dogs underwent free gingival autografts involving the maxillary canine and its attached gingiva. Comparative investigations relating the architectural transformations and endothelial permeability of the capillaries were made histopathologically, with graft epithelialization as an indicator. Microscopic findings revealed that the subepithelial capillaries transformed from loop structure into glomus-like structures. The endothelium changed ultrastructurally from the continuous type to the fenestrated. This occurred during the most active graft epithelialization phase. By the time the epithelium of the graft had matured, the fenestrated microvascular structure reverted to the continuous type and changed from a glomus-like structure to a network capillary system. However, by the 84th postoperative day, the subepithelial capillaries, still exhibiting network structure, had not yet returned to the loop structure indigenous to the gingiva. Observations indicated that transformation of the structure of the nourishment-providing capillaries was attendant to and simultaneous with the changes brought about by graft epithelialization.

Animals↗
PubMed1988

Autotransplantation of the superior cervical ganglion into the brain. A possible therapy for Parkinson's disease.

The superior cervical ganglion (SCG) of rats was transplanted into their own parietal cortex. Four weeks after implantation, catecholamine histofluorescence revealed many transplanted catecholamine cells in the cortex. However, no fibers extended from the transplanted tissue to the cerebral cortex. In a second group of rats which had been pretreated with 6-hydroxydopamine (a specific neurotoxin to the catecholamine neuron), some showed extension of catecholamine fibers to the cerebral cortex. To simulate an animal model of Parkinson's disease, MPTP (1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine) was administered to five monkeys. Two weeks after MPTP administration, dopamine terminals in the caudate nucleus disappeared. After autotransplantation of the SCG into the caudate nucleus of these monkeys, many of the transplanted SCG cells extended axons beyond the graft into the caudate nucleus. These results show that transplanted SCG cells survived well in the brain. Under special circumstances, such as a shortage of catecholamine in the brain, implanted SCG cells extended their axons into the brain. It is suggested that autotransplantation of SCG grafts may be a new therapy for Parkinson's disease.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1988

[Long-term survival in malignant atrophic papulosis: a case report and review of the Japanese literature].

Malignant atrophic papulosis (MAP) is characterized by skin lesion and high mortality rate caused by perforation of the GI tract or involvement of the central nervous system. Approximately 100 cases have been reported in the world literatures, but etiology is unknown. A 44-year-old female patient was admitted for chest and abdominal pain with characteristic papuloses, which had been noted by the patient seven years ago. Because of positive peritoneal irritation and intraabdominal free air, exploratory laparotomy was done. Multiple red inflammatory or yellow atrophic maculae on the entire intestine with no obvious perforation but with air-leak were found. Those perforations were closed with seromuscular sutures. The patient is doing well sixteen months after surgery. Fourteen MAP cases have been reported in the Japanese literature. As is found in the world literature, the mortality rate is extremely high. All of reported cases were initially diagnosed because of the particular skin lesions. Abdominal symptoms developed in 10 cases and six of these died. Three cases died within three weeks after bowel resection. There are three surviving cases. One was treated conservatively even though intraabdominal free air was present. Two had three operations, including one simple closure and two intraabdominal explorations. According to this result, a bowel resection should not be performed on MAP patients because of this high mortality. Administration of anticoagulants, i.e., heparin, prostaglandin E1 and ticlopidine seems to be effective in alleviating symptoms and might prevent further deterioration.

Adult↗
PubMed1988

Lack of complement activation by human IgA immune complexes.

Complement activation may play an important role in renal injury associated with glomerular deposition of IgA immune complexes. The ability of naturally occurring human IgA immune complexes (IgA-IC) and covalently cross-linked human IgA oligomers (X-IgA) to activate complement were examined in vitro and in vivo. Large-sized IgA-IC were isolated from a patient's serum by affinity purification (Jacalin-Sepharose) and gel chromatography. Stable X-IgA were prepared by chemical cross-linking with a heterobifunctional reagent, N-succinimdyl 3-(2-pyridyl-dithio) propionate (SPDP). Treatment of fresh normal human serum with large amounts of either IgA-IC or X-IgA failed to activate C3. The C3 consumption was measured immunochemically by the decrease of the B antigen on the native C3 and by the generation of iC3b. Addition of these complexes to serum did not result in cleavage of factor B. Administration of human IgA-IC or X-IgA to mice, killed after 6 h, resulted in glomerular deposition of IgA. Despite the presence of intense glomerular IgA deposits no C3 was detected. Collectively, these findings suggest that neither soluble nor renal localized human IgA complexes activate complement.

Animals↗
PubMed1988

[Transplantation of the superior cervical ganglion into the brain--a new experimental therapy of Parkinson disease].

To supplement catecholamine deficit in the brain with Parkinson disease, we have aimed to transplant the superior cervical ganglion (SCG), which contains norepinephrine and dopamine, into the brain. 1. Transplantation of SCG into rat cerebral cortex SCG was transplanted into the same rat's parietal cortex. Three weeks after the transplantation, catecholamine histofluorescence revealed many transplanted catecholamine cells in the cortex. However, no fibers extended from the transplanted tissue to the cerebral cortex. Some catecholamine fibers extended to the cerebral cortex where 6-OHDA (a specific neurotoxin to the catecholamine neuron) had been pretreated. 2. Transplantation of SCG into the caudate nucleus of MPTP-induced Parkinson monkey For animal model of Parkinson disease, MPTP (1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine) was administered to 5 monkeys. Tow weeks after MPTP administration, dopamine terminals disappeared in the caudate nucleus. After transplantation of SCG in the same animal, many transplanted SCG cells extended their axons to the caudate nucleus. The present results showed that transplanted SCG cells were well survived in the brain. Under a special circumstance such as shortage of catecholamine in the brain, transplanted SCG cells extended their axons into the brain. It is suggested that the transplantation of SCG can be a new therapy for Parkinson disease.

Animals↗
PubMed1988

[Metrizamide encephalopathy in a child with hydrocephalus--effects of L-threo-DOPS on persistent disturbance of consciousness and L-dopa on extrapyramidal symptoms].

This report describes a case of metrizamide encephalopathy with persistent disturbance of consciousness and extrapyramidal symptoms. These two conditions have rarely been reported among the various adverse effects of metrizamide. An 11-year-old girl had been in almost good health until she was ten years old, at which time she received a ventriculo-peritoneal shunt operation, suffering from hydrocephalus of unknown etiology. At the age of eleven, she was admitted to our hospital due to hydrocephalus recurrence. She was examined by metrizamide shunt-gram (1200 mg iodide/4 ml). On the next day, she became drowsy. The CT scan disclosed the periventricular penetration of metrizamide into the medial part of the thalamus and the caudate nucleus. Thirteen days later, disturbance of consciousness continued, and extrapyramidal symptoms, that is, rigo-spasticity and postural tremor, were observed. Oral administration of L-threo-DOPS, the direct precursor of noradrenaline, was effective against the persistent disturbance of consciousness and L-DOPA was effective against the extrapyramidal symptoms. She soon recovered almost to normal and no neurological deficit remained. We thus conclude that the CT scan findings and effects of L-threo-DOPS and L-DOPA suggest that metrizamide encephalopathy in this case were respectively due to its periventricular penetration into the medial part of the thalamus and the caudate nucleus, and the resultant deficiency of the ascending noradrenergic reticular activating system and the nigrostriatal dopaminergic system.

Basal Ganglia Diseases↗
PubMed1988

[Flow imaging of the cardiovascular system using magnetic resonance imaging].

Blood flow images by magnetic resonance imaging (MRI) using a 0.25 T unit were evaluated for nine normal volunteers and 108 subjects with a variety of cardiovascular abnormalities. Using the non-gated short-spin echo (SE) technique, blood flow in the cardiovascular systems was not imaged in the normal volunteers. Using end-systolic and end-diastolic SE techniques for the normal subjects, blood flow in the cardiac chambers was not clearly imaged. Blood flow in the ascending aorta and aotric arch often did not appear in the gated SE images of the normal subjects. However, blood flow in the descending aorta was often observed in the gated SE images. Blood flow imaging was demonstrated by both non-gated and gated SE techniques in regions where blood flow was relatively slow; for example, in the left atrium of mitral stenosis, in an aortic aneurysm, in a false lumen of an aortic dissection, and in the left ventricle having old myocardial infarction. Using the non-gated inversion recovery (IR) technique, no blood flow was imaged in the cardiovascular system except in the left atrium of one case with mitral stenosis. Using the non-gated short SE technique, there was good correlation between the thrombus formation and the presence of blood flow images in the left atria of 17 patients with mitral stenosis, and in the aneurysmal portions of the aorta or in the false lumens of aortic dissection of 18 patients. It was suggested that mural thrombi in such diseases were related to the relatively slow blood flow. Blood flow imaging easily distinguished stagnant blood flow from mural thrombi using non-gated short SE, end-systolic SE, and IR techniques. Thus, blood flow imaging using MRI should become an important means of evaluating the cardiovascular system.

Adult↗
PubMed1988

[Right ventricular function in cardiovascular disease evaluated by magnetic resonance imaging].

The usefulness of ECG-gated magnetic resonance imaging (MRI) in evaluating right ventricular architecture and function was assessed by measuring right ventricular wall thickness, wall motion, and areas of the right ventricular cavities of seven normal subjects and 46 with cardiac disease, including atrial septal defect (ASD: six cases), hypertrophic cardiomyopathy (HCM: 19), dilated cardiomyopathy (DCM: eight), and old myocardial infarction (OMI: 13 cases). A superconductive MRI system was used. Transverse images at the level of the tricuspid valve were obtained for measurements. ECG-gated MRI clearly showed the right ventricular myocardium throughout the cardiac cycles and facilitated measuring wall thickness and cross-sectional areas of the right ventricular cavity in all subjects. In normals the mean value and standard deviation of the anterior wall thickness of the right ventricle and the area index of the right ventricular cavity at end-diastole were 3.4 +/- 0.7 mm and 10.6 +/- 1 cm2/m2, respectively. The anterior and lateral walls and tricuspid annulus moved inward to the right ventricular cavity in systole, and the excursion of the lateral wall and tricuspid annulus was larger than those of the anterior wall. The interventricular septum (IVS), however, moved outward to the left ventricle in systole. The anterior wall thickness of the right ventricle in patients with HCM was 5.8 +/- 1.4 mm thicker than that of normal subjects. In contrast to normals, the area index of the right ventricular cavity was larger in patients with ASD (18.4 +/- 5.4 cm2/m2) and smaller in patients with HCM (9.1 +/- 1.6 cm2/m2). The IVS moved inward in all patients with ASD and in several patients with HCM. The anterior and lateral wall motion was decreased in patients with ASD and DCM.

Adult↗
PubMed1988

Autoantibody against erythrocyte protein 4.1 in a patient with autoimmune hemolytic anemia.

We observed the presence of a new autoantibody, anti-erythrocyte protein 4.1, in a patient with autoimmune hemolytic anemia (AIHA). Western blotting analysis revealed that IgG from the patient's plasma reacted with erythrocyte protein 4.1. However, among other patients with hemolytic diseases (six having AIHA and three each having either hereditary spherocytosis, elliptocytosis, or lead poisoning) as well as among control subjects, no antibody activity to protein 4.1 was observed. In addition to the anti-protein 4.1 antibody, two different kinds of anti-erythrocyte antibodies were detected by conventional serological studies in this patient. One of them was an anti-Ena-like antibody in the eluate from the patient's erythrocytes, while another was the anti-S-specific antibody in the plasma. An elution study and an absorption study using S antigen-positive erythrocytes demonstrated that the anti-protein 4.1 antibody differed from both the anti-Ena-like antibody and the anti-S antibody. Familial analysis of the patient revealed the same antibody in her brother, who did not have hemolytic anemia. These results demonstrate that anti-protein 4.1 antibody is considered to be included in the spectrum of anti-cytoskeleton autoantibodies, which have been observed in patients having increased cell lysis as well as in healthy subjects.

Anemia, Hemolytic, Autoimmune↗
PubMed1987

High-performance liquid chromatographic drug analysis by direct injection of whole blood samples. I. Determination of moderately hydrophobic drugs incorporated into blood corpuscles.

Amounts of a moderately hydrophobic drug incorporated into blood corpuscles were determined by column switching high-performance liquid chromatography with direct injection of whole blood samples. Some modifications were required in order to apply the conventional direct injection method to whole blood samples, as follows. Clogging of the pre-column by blood corpuscles or cytomembranes was avoided by using an end-fitting filter with pore size larger than 40 micron, and accordingly a packing with particle size larger than 40 micron was used. Haemoglobin was decomposed in contact with ODS silica gel and reduced the column efficiency. The protein-coated ODS pre-column (pore size less than 7 nm) was restored by washing with 0.1 M phosphate buffer (pH 3.0) containing 50% acetonitrile. Sodium dodecyl sulphate solution (0.5%, w/v) was preferable for rinsing and removes material remaining in the pre-column. A whole blood sample containing carbamazepine was directly injected into the pre-column, then blood cells were haemolysed promptly in contact with a mobile phase of low salt concentration. The total amount of carbamazepine could be determined with a coefficient of variation of 1.9% (within-run). Carbamazepine incorporated into rabbit blood cells (haematocrit value 33.6%) was determined to be 1.1-1.3 times higher than the concentration in plasma. Adsorption on the cytomembranes was not observed.

Blood Cells↗
PubMed1987

High-performance liquid chromatographic drug analysis by direct injection of whole blood samples. II. Determination of hydrophilic drugs.

The determination of hydrophilic drugs in whole blood by direct injection high-performance liquid chromatography was investigated. A pre-column equipped with an inlet filter of pore size 40 microns and an outlet filter of pore size 2 microns was packed with Butyl Toyopearl 650-M. A whole blood sample was injected directly into the pre-column to trap proteins, hydrophobic compounds and blood cytomembranes, and hydrophilic compounds emerged into an analytical column (Nucleosil 5SA, particle size 5 microns) and were determined after column switching. Proteins in 40 microliters of rabbit whole blood were adsorbed in the pre-column (0.63 ml of wet gel) in 0.4% perchloric acid solution. The recovery of procainamide and N-acetylprocainamide from whole blood was quantitative with good reproducibility (coefficient of variation less than 4%). It was shown that procainamide added to rabbit whole blood was subjected to N-acetylation by N-acetyltransferase in blood cells.

Acecainide↗
PubMed1987

High-performance liquid chromatographic drug analysis by direct injection of whole blood samples. III. Determination of hydrophobic drugs adsorbed on blood cell membranes.

The determination of strongly hydrophobic drugs in whole blood by high-performance liquid chromatography was investigated and the amount adsorbed on cytomembranes was measured. A polyvinyl resin, TSK Gel HW-65, was used as the pre-column packing. Proteins, cytomembranes and endogenous hydrophilic components flowed through the pre-column in aqueous medium, but strongly hydrophobic substances such as chlorpromazine were adsorbed and then eluted by backflushing into an ODS analytical column. The recovery of chlorpromazine from whole blood was 103.3% with a coefficient of variation of 3.4% (n = 10). This method gave the total amounts in blood, representing not only the amount bound to proteins but also that bound to cytomembranes. The difference in the concentrations determined in whole blood and the supernatant of haemolysed whole blood gave the value adsorbed on cytomembranes.

Adsorption↗
PubMed1987

Composition of IgA immune complexes precipitated with polyethylene glycol. A model for isolation and analysis of immune complexes.

Covalently cross-linked large and intermediate-sized IgA oligomers, prepared with IgA anti-dinitrophenyl (DNP) and bis-DNP-pimelic acid ester, were used to examine the ability of different concentrations (3.5%, 5% and 7%, w/v) of polyethylene glycol (PEG) to precipitate IgA immune complexes (IgA-IC). The size of the IgA-IC precipitated with PEG was determined by gradient polyacrylamide gel electrophoresis and quantitative autoradiography. The standard concentration of 3.5% PEG precipitated only a minor fraction (20%) of the IgA-IC. In contrast, 5% and 7% PEG precipitated 45% and 79% of the complexes, respectively. To test the influence of the antigen on the PEG assay. IgA-IC prepared with IgA anti-DNP and DNP conjugates of either bovine serum albumin or Ficoll were also used. Approximately 38% of these IgA-IC were precipitated with 3.5%, PEG. By comparison, the concentration of 5% and 7% PEG precipitated 60% and 76% of the IgA-IC, respectively. Distilled water rather than the standard borate-buffered saline was shown to be the optimal solvent for resolubilization of the PEG precipitates. Serum samples from 22 IgA nephropathy patients and 12 normal donors were tested with 3.5%, 5% and 7% PEG. Only the 7% PEG assay showed a significant difference between patients and controls (P less than 0.001) in the IgA levels of precipitates. Thus, the use of 7% PEG is recommended for the detection, isolation and analysis of large- and intermediate-sized IgA-IC.

Antigen-Antibody Complex↗
PubMed1987

Intrahepatic portal-systemic shunt: its etiology and diagnosis.

Four cases of enormous shunt between portal and hepatic veins (portal-hepatic venous shunt) are reported with special reference to sonographic and portographic findings. Ultrasonography, an examination for screening, delineated a snail-like anechoic area in the liver, its connection with the portal and hepatic veins, and marked dilatation of the veins connecting with the shunt. Transarterial or percutaneous transhepatic portography, a method for definitive diagnosis, demonstrated large pooling of the contrast medium flowing from the dilated portal branch and subsequent visualization of the hepatic vein. The etiology and prognosis are unknown at present. The most likely pathogenesis for this shunt seemed to be a congenital anomaly, namely, persistence of the omphalomesenteric venous system. With recent advances in and the more frequent use of real-time ultrasonography, detection of this kind of vascular abnormality will doubtless increase.

Female↗