Biomedical subjects

M Sakamoto

Publications and source records attributed to M Sakamoto.

At least 595 records · Page 33Linked to original sources

PubMed1990

[Distal aneurysm of posterior inferior cerebellar artery: report of two cases--pitfall in diagnosis].

Two cases treating aneurysms of the distal PICA were reported, and 36 cases with 39 aneurysms in the literatures in Japan were reviewed concerning the distribution of aneurysms and their findings on CT. Case 1; a 68-year-old female suffered from sudden onset of severe headache and nausea. On admission, it was found she was lethargic. However, her consciousness deteriorated down to semicoma with tetraparetic condition soon after. CT revealed subarachnoid hemorrhage in the basal, quadrigeminal and supravermian cisterns and blood clots in the entire ventricle. Cerebral angiography demonstrated an aneurysm located at the distal segment of the left PICA. She was initially treated conservatively because of being in Hunt and Kosnik Grade 5, and then, 3 weeks after onset, suboccipital craniectomy was performed and the aneurysm was clipped successfully. Case 2; a 60-year-old, female, suddenly experienced severe suboccipitalgia and vomiting. CT revealed subarachnoid hemorrhage in the entire subarachnoid space and intraventricular hemorrhages in the 4th, 3rd and lateral ventricles. Subsequently cerebral angiography was performed and left VAG demonstrated an aneurysm at the left A2-A3 junction. She underwent bifrontal craniotomy and the aneurysm was clipped via the interhemispheric approach. Her postoperative course was uneventful. Postoperative left CAG showed successful clipping of the aneurysm. However, left VAG suggested an aneurysm-like shadow in the right PICA. Right BAG carried out one week later demonstrated an aneurysm at the distal segment of the right PICA. This aneurysm was then clipped successfully under suboccipital craniectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1990

[A clinical evaluation of cefdinir in pediatric infections].

Cefdinir (CFDN), a new oral cephalosporin, was administered to 10 patients with various infections and the following results were obtained. 1. Clinical responses in 10 patients (1 patient with rhinitis, 2 with sinusitis, 1 with pharyngitis, 1 with tonsillitis, 4 with scarlet fever and 1 with abscess) were excellent in 6 and good in 4 with an efficacy rate of 100%. 2. Eleven species of bacteria were isolated (3 of Staphylococcus aureus, 6 of Streptococcus pyogenes and 2 of Haemophilus influenzae) and all of them were eradicated by the treatment with CFDN. 3. No side effects or abnormal laboratory test values were noted. None of the patients refused to take the drug.

Administration, Oral↗

PubMed1990

Effects of left heart bypass on right ventricular performance. Evaluation of the right ventricular end-systolic and end-diastolic pressure-volume relation in the in situ normal canine heart.

Although left heart bypass has gained popularity as a powerful technique to assist the severely failed left heart, apparent right heart failure has often developed during the bypass procedure. We investigated whether the coexisting right heart failure is attributable to the left heart bypass in 16 open-chest dogs. We evaluated the effects of left heart bypass on the right ventricular systolic properties by the slope of the end-systolic pressure-volume relation and its effects on the diastolic properties by chamber compliance. Overall right ventricular performance was assessed by the end-diastolic pressure versus cardiac output relationship. The left heart bypass decreased the slope slightly when the assisted flow ratio exceeded 75% (-14% +/- 8% at the assisted flow ratio of 100%, p less than 0.02) and thus had a deleterious influence on right ventricular performance. The left heart bypass, on the other hand, had a counteracting beneficial influence on right ventricular performance through the increase in chamber compliance (38% +/- 5%, p less than 0.01) and the decrease in pulmonary arterial input resistance (-15% +/- 12%, p less than 0.01). The net effect of the left heart bypass was the increase in cardiac output (20% +/- 2%, p less than 0.05) for any given right ventricular end-diastolic pressure. We conclude that in normal hearts the left heart bypass augments right ventricular performance. We ascribe these beneficial effects to diastolic ventricular interdependence and afterload unloading.

Animals↗

PubMed1990

[Examination by densitometer on visualization of non-ionic contrast medium (iohexol) in excretory urography. 1. Visualization by bolus injection].

The visualization of non-ionic contrast medium (Omnipaque 300) in the excretory urography by bolus injection was examined with regard to the normal sided urinary tract in patients with urolithiasis using a densitometer and further compared with that of ionic contrast medium (60% Urografin). In relation to the photographing method, both contrast media showed an increasing frequency of high opaque site in the order of Tomo, A-P and P-A images, which tended to shift from the upper to the lower urinary tract. In relation to the site of determination, both agents showed a good image in the upper urinary tract by the each photographings, while P-A image was better than A-P image in the lower urinary tract, suggesting their high usefulness for the imaging diagnosis. The visualization in relation to the contrast medium used was better in Omnipaque 300 groups than in 60% Urografin group with a significant difference (P less than 0.05-0.01) in the calyx and pelvis of the kidney by the each photographings, suggesting a high usefulness of non-ionic contrast medium. A densitometer seemed to be a useful means for evaluation and examination of the visualization with excellent objectivity as compared with conventional macroscopic methods.

Absorptiometry, Photon↗

PubMed1990

[Examination by densitometer on visualization of non-ionic contrast medium (iohexol) in excretory urography. 2. Changes in visualization by DIP].

Changes in the visualization of non-ionic contrast medium (Omnipaque 300) in the urography by DIP were monitored for the normal sided urinary tract in patients with urolithiasis using a densitometer. In addition, changes of the visualization in relation to the dose of contrast medium used was examined and compared with that of ionic contrast medium (60% Urografin). The optimum photographing time was 15 minutes in the upper urinary tract (nephrogram, calyx, pelvis, upper ureter) and 20 minutes in the lower urinary tract (lower ureter, urinary bladder). Visualization of high usefulness appeared to be obtainable for the imaging diagnosis by DIP in subjects with normal renal function even when the photographing was completed 20 minutes after infusion of contrast medium. In relation to the doses of contrast medium used, no difference was observed in the variation pattern but a better imaging was obtained in the 100 ml group than 50 ml group with a significant difference (P less than 0.01) in the 15-20 minute images of the calyx and pelvis of the kidney and urinary bladder in particular, this suggested the high usefulness of 100 ml dosing for the imaging diagnosis. In the visualization of ionic contrast medium, some difference was observed in the variation pattern and the visualization was better in Ominpaque 300 groups than in 60% Urografin group with a significant difference (P less than 0.01) in the 15-20 minute images of the calyx and pelvis of the kidney and urinary bladder. This suggested the high usefulness of non-ionic contrast medium.

Absorptiometry, Photon↗

PubMed1989

Cell-adhesive immunoglobulin M in human plasma.

Human plasma contains a cell-adhesive protein that has a structure related to immunoglobulins. This protein was purified by affinity chromatography on an elastin-Sepharose column and by Mono Q anion-exchange chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis under non-reducing and reducing conditions revealed that this protein is a kind of immunoglobulin M (IgM). Antibodies against the mu chain and against the Fc region of IgM inhibited the adhesion of cells to this protein. Addition of the peptide GRGDS into media inhibited the adhesion, too. These results suggest that this protein is a special subset of IgM having a cell-binding sequence in the Fc region. We propose the name "cell-adhesive immunoglobulin M (CA-IgM)" for this protein. CA-IgM binds to alpha-elastin and laminin suggesting that it may play a role in the interaction between cells and the extracellular matrix.

Animals↗

PubMed1989

Mineralization induced by beta-glycerophosphate in cultures leads to a marked increase in collagenase synthesis by mouse osteogenic MC3T3-E1 cells under subsequent stimulation with heparin.

The clonally derived mouse osteoblast-like cell line MC3T3-E1 was shown to produce latent collagenase (approximately 0.2 units/ml) under stimulation with either heparin or parathyroid hormone in confluent cultures. However, it was found that MC3T3 E1 cultures which were first induced to undergo mineralization by the addition of beta-glycerophosphate and were subsequently stimulated with heparin showed an approximately ten-fold increase in collagenase synthesis. MC3T3-E1 cell collagenase from a small sample of serum-free culture medium was purified 49-fold to a specific activity of 200 units/mg protein with a yield of 14% by heparin-sepharose affinity chromatography and ion-exchange high performance liquid chromatography. This new mineralization-primed cell culture system may be a valuable model for the study of osteoblast collagenase.

Alkaline Phosphatase↗

PubMed1989

Effect of TCDD on the density of Langerhans cells in murine skin.

Tetrachlorodibenzo-p-dioxin (TCDD) is a prototype for a group of toxic polyhalogenated aromatic hydrocarbons. We have studied the effect of TCDD on skin, specifically the difference in cutaneous response of congenic haired (hr/+) and hairless (hr/hr) mice. Topical application of 0.6 microgram of TCDD induces epidermal hyperplasia/hyperkeratinization in the skin of hr/hr mice, but does not affect the epidermis of congenic hr/+ littermates. Suppression of various parameters of the immune response has been found to be another effect of TCDD exposure in experimental animals. In the present study, we investigated the effect of topical treatment with TCDD on the density of epidermal immune cells, the Langerhans cells (LC), in the skin of hr/hr and hr/+ mice. Results showed that TCDD-induced epidermal hyperplasia/hyperkeratinization in skin of hr/hr mice is accompanied by an increase in the density of LC. In the skin of hr/+ mice, in which TCDD exposure does not induce hyperplastic changes, LC densities are not affected. The increase in LC densities in TCDD-treated hr/hr mouse skin did not result in increased sensitivity of the skin to contact hypersensitization with dinitrofluorobenzene, as measured by changes in ear thickness. When hr/hr murine skin was grafted into skin of hr/+ mice and the entire dorsal skin (including the graft) treated with TCDD, LC were increased in the grafted skin, but not in the surrounding hr/+ skin. Conversly, when hr/+ murine skin was grafted into hr/hr mice and both treated with TCDD, there was no increase in the density of LC in the grafted hr/+ skin. Concomitant treatment of hairless mice with TCDD and with indomethacin did not affect the increase in the density of LC induced by TCDD treatment alone. These findings suggest that TCDD-induced epidermal changes in hr/hr murine skin involve production of factors which mediate the increase in epidermal LC.

Adenosine Triphosphatases↗

PubMed1989

Purification and characterization of Ki antigen and detection of anti-Ki antibody by enzyme-linked immunosorbent assay in patients with systemic lupus erythematosus.

Ki antigen from rabbit thymus extract was purified by ammonium sulfate precipitation, anti-Ki affinity chromatography, and high pressure liquid chromatography gel filtration. The purified Ki antigen gave a single polypeptide with an MW of 32,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and it specifically reacted with anti-Ki antibody by immunoblotting. The isoelectric point of the Ki antigen was found by isoelectric focusing to be 4.3. An enzyme-linked immunosorbent assay using the purified Ki antigen was established, and the clinical significance of the anti-Ki antibody in systemic lupus erythematosus (SLE) was studied. Thirty of 140 patients with SLE (21.4%) had anti-Ki antibody by enzyme-linked immunosorbent assay, whereas 11 (7.9%) were positive by double immunodiffusion. Analysis of clinical and serologic data on patients with SLE suggested a higher prevalence of central nervous system involvement in patients with anti-Ki antibody.

Antibodies↗

PubMed1989

The complete sequence of the rice (Oryza sativa) chloroplast genome: intermolecular recombination between distinct tRNA genes accounts for a major plastid DNA inversion during the evolution of the cereals.

The entire chloroplast genome of the monocot rice (Oryza sativa) has been sequenced and comprises 134525 bp. Predicted genes have been identified along with open reading frames (ORFs) conserved between rice and the previously sequenced chloroplast genomes, a dicot, tobacco (Nicotiana tabacum), and a liverwort (Marchantia polymorpha). The same complement of 30 tRNA and 4 rRNA genes has been conserved between rice and tobacco. Most ORFs extensively conserved between N. tabacum and M. polymorpha are also conserved intact in rice. However, several such ORFs are entirely absent in rice, or present only in severely truncated form. Structural changes are also apparent in the genome relative to tobacco. The inverted repeats, characteristic of chloroplast genome structure, have expanded outward to include several genes present only once per genome in tobacco and liverwort and the large single copy region has undergone a series of inversions which predate the divergence of the cereals. A chimeric tRNA pseudogene overlaps an apparent endpoint of the largest inversion, and a model invoking illegitimate recombination between tRNA genes is proposed which accounts simultaneously for the origin of this pseudogene, the large inversion and the creation of repeated sequences near the inversion endpoints.

Amino Acid Sequence↗

PubMed1989

A new method of modified radical mastectomy for breast cancer.

We have developed a new type of modified radical mastectomy, the method and clinical results of which are reported herein. In this operation, axillary dissection is performed by the following two approaches. Firstly, the axillary contents are dissected from the highest possible subclavicular point to the pectoralis minor muscle, after partially cutting the sternocostal origin of the pectoralis major muscle. The second approach is from the posterior aspect of the pectoralis minor muscle to the lateral portion of the latissimus dorsi muscle. Parasternal dissection can also be performed for stage II and IIIa cancers with a central or medial tumor. After lymph node dissection, the detached edge of the sternocostal origin of the pectoralis major muscle is resutured to cover the parasternal region. Thus, complete dissection of the axillary nodes is performed whilst preserving the pectoralis major and pectoralis minor muscles. Good clinical results were achieved with respect to radicality, cosmetic effects and function in 28 patients with stage I, II, and IIIa breast cancers who were followed up for between 5 to 8 years. This new operation may therefore be adopted for the majority of patients with Stage I, II, or IIIa cancers, unless massive infiltration into the pectoralis major muscle has occurred. Preservation of both the pectoralis major and pectoralis minor muscles results in a good cosmetic appearance, good functioning of the arm and easy reconstruction of the breast following mastectomy.

Adult↗

PubMed1989

Eye movements induced by microinjection of GABA agonist in the rat substantia nigra pars reticulata.

Injection of muscimol (GABA agonist) in the substantia nigra pars reticulata (SNr) of the alert rat induced a continual repetition of fast eye movements to the contralateral side, each of which was followed by a slow returning movement. The fast eye movements were similar to spontaneous saccades. Larger saccades were accompanied by contralateral neck muscle activity. We suggest that the SNr plays an important role in control of eye movements in the rat.

Animals↗

PubMed1989

The effect of substrate composition and condition on resorption by isolated osteoclasts.

Osteoclasts isolated from 10-day-old rabbits were studied in a cell culture system to obtain further insight into the possible mechanisms involved in the process of bone resorption. Osteoclasts were cultured on the surfaces of devitalized mammalian bones, a composite of polycrystalline synthetic hydroxyapatite and geological single crystal hydroxyapatite. The structural interaction of osteoclasts with these various substrates was morphologically characterized by using a scanning electron microscope. Viable osteoclasts were observed to adhere and extend pseudopodia and filopodia for all cases of calcium-phosphate surfaces. However, actual resorbing process was only observed in devitalized bone surfaces. Resorption pits of various sizes were found in multiple series and showed a preference for mineral-exposed area over collagen-exposed area. The difference observed between resorption of those areas of bone surface and the failure of osteoclasts to resorb non-tissue substrates are discussed in relation to current theories of the mechanisms of mineral dissolution and resorption in mammalian calcified tissues.

Animals↗

PubMed1989

Effects of temephos on zooplankton communities in enclosures in a shallow eutrophic lake.

An organophosphorus insecticide, temephos, was applied to large-volume (105 m3) enclosures set up in a shallow eutrophic lake. Application of the chemical at a target concentration of 500 microg litre(-1) eliminated almost all zooplankters. No recovery of cladocerans was evident at the termination of the experiment (47th day after the treatment). Copepods showed a slight recovery after having been absent for 26 days in one enclosure and 40 days in another. The residual chemical remaining in the water until the final day may have suppressed the recovery of the crustacean zooplankters. The rotifer community was reconstructed 16-20 days after the treatment. However, the species composition of this community differed from that of the rotifer community in the control enclosures. Rotifer species might therefore show differences in susceptibility to temephos.

Journal Article↗

PubMed1989

Multicentric independent development of hepatocellular carcinoma revealed by analysis of hepatitis B virus integration pattern.

Two separate nodular lesions of hepatocellular carcinoma (HCC) were surgically removed from a patient with positive serum hepatitis B surface antigen. Southern blot analysis of DNA from the two separate HCC lesions showed different restriction patterns of integrated hepatitis B virus DNA, indicating their independent origins. The two lesions were composed mainly of poorly differentiated HCC; however, well-differentiated HCC was also observed in the periphery of the lesions. This histological finding is consistent with the multistep and independent development of HCC in each site of the liver.

Aged↗

PubMed1989

Cardiomyopathy characterized by abnormal accumulation of desmin-type intermediate filaments in cardiac muscle fibers. A case report and review of the literature.

A 42-year-old Japanese male, who had been suffering from congestive heart failure and electrocardiographic abnormalities (A-V block, intraventricular conduction disturbance, ventricular tachycardia), died after a clinical course of 2 years and 1 month. Macroscopic investigation revealed dilation of the left ventricle and thickening of the right ventricular wall. The unique finding in this case was a circumferential fibrous scar in the median circular layer and outer oblique layer of the left ventricular wall. Biopsy and autopsy materials revealed diffuse loss of myofibrils in the central zone of cardiac muscle fibers, and replacement with aniline blue-positive homogeneous material (17-35% of the area of one muscle fiber). Electron microscopy revealed abnormal accumulation of fine filamentous material (7.5-25 nm in diameter), which was immunohistochemically proved to be desmin-type intermediate filament. Moreover, sarcoplasmic reticulum-like material was detected in the degenerated area. At autopsy, degeneration was detected all over the heart. The ventricular muscle fibers were more severely affected than the atrial muscle fibers. The conduction system was also affected, in some parts more severely than the surrounding ordinary muscle fibers. The pathogenesis of this disorder remains to be clarified.

Adult↗

PubMed1989

Effects of fentanyl on carotid sinus baroreflex control of circulation in rabbits.

The effects of intravenous administration of fentanyl on carotid sinus baroreflex control of hemodynamics were investigated in chronically instrumented rabbits. Carotid sinus baroreflex was assessed by bilateral carotid occlusion (BCO), and the responses of mean arterial pressure (MAP), heart rate (HR), mean ascending aortic flow (MAF), and total peripheral resistance (TPR) were obtained. Hemodynamic responses to BCO were examined with cumulative doses of 5, 10, and 15 micrograms/kg of fentanyl. Fentanyl did not affect MAP and TPR but reduced HR and MAF dose dependently. Fentanyl did not attenuate the MAP response to BCO significantly. In contrast, fentanyl significantly attenuated the TPR response from 0.126 +/- 0.003 to 0.104 +/- 0.005 mmHg.min-1.ml-1 and augmented the HR response from 31 +/- 2 to 47 +/- 3 beats/min in the conscious state and at 15 micrograms/kg of fentanyl, respectively. The administration of atropine after the fentanyl attenuated MAP and HR responses to 79.9 and 27.7% of those of 10 micrograms/kg of fentanyl, respectively. We suggest that these dissociated hemodynamic responses reflect the vagotonic and sympatholytic effects of fentanyl on the baroreflex pathways.

Animals↗

PubMed1989

Functional properties of monkey caudate neurons. I. Activities related to saccadic eye movements.

1. We recorded single cell activities in the caudate nucleus of the monkeys trained to perform a series of visuomotor tasks. In the first part of this paper, we summarize the types and locations of neurons in the monkey caudate nucleus. In the second part, we report the characteristics of neurons related to saccadic eye movements. 2. Neurons were classified into two types in terms of spontaneous discharge pattern. A majority of the neurons (2,287/2,559, 89%) had very low-frequency discharges (mostly less than 1 Hz). The rest (n = 272) showed irregular-tonic discharges (3-8 Hz) with broad spikes. 3. Of 2,559 neurons tested, 867 showed spike activity related to some aspects of the tasks; 502 neurons showed discharges in response to environmental changes outside, not in relation to, the tasks. None of the neurons responsive in or outside the tasks belonged to the irregular-tonic type. 4. The task-related activities were classified as: Saccade-related, Visual, Auditory, Cognitive, Fixation-related, and Reward-related. The activities detected outside the tasks were classified into: Visual, Auditory, Movement-related, Reward-related, and Other. Few neurons had both task-related and task-unrelated activities. 5. The locations of recorded neurons were determined using a coordinate system based on the anterior and posterior commissures. Task-related neurons were clustered longitudinally in the central part of the caudate. Neurons responsive outside the tasks were more widely distributed; specifically, auditory neurons were in the medial part, whereas movement-related neurons were in the lateral part. The irregular-tonic neurons were dispersed all over the caudate. 6. The monkey was trained to fixate on a spot of light on the screen and, when the spot moved, to follow it by making a saccade. A visually guided saccade occurred when the spot moved to another location without a time gap (saccade task). A memory-guided saccade occurred when the spot first disappeared and after a time gap reappeared at a fixed location (saccade with gap task). By delivering a cue stimulus while the monkey was fixating, a memory-guided saccade was elicited to a randomly chosen location (delayed saccade task).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗