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Biomedical subjects

M Kawamura

Publications and source records attributed to M Kawamura.

At least 1,045 records · Page 58Linked to original sources

Periportal high intensity on T2-weighted MR images in acute viral hepatitis.

The frequency and degree of periportal high intensity (PHI) on T2-weighted images in 28 patients (32 MR studies) with acute viral hepatitis were analyzed with regard to the various levels of serum glutamic-oxaloacetic transaminase (SGOT) and clinical phases. Periportal high intensity was found in 16 of 32 MR studies (50%) and no definite PHI was found in 7 studies (22%). Periportal high intensity appeared when the SGOT level was greater than 500 IU or when the phase of the disease was early. Follow-up studies revealed that PHI decreased during clinical recovery. We conclude that the degree of PHI on T2-weighted images reflects the severity of the disease in acute viral hepatitis.

Acute Disease↗

Serum creatine phosphokinase levels during treatment with beta-adrenoreceptor blocking agents.

We administered four beta-adrenoreceptor blocking agents--pindolol (15 mg/day), propranolol (60 mg/day), carteolol (15 mg/day), and labetalol (150 mg/day)--to essential hypertensive patients, and followed the changes in levels of serum creatine phosphokinase (CPK) and its isoenzymes for 1 year. Blood pressure was reduced almost equally by all drugs, but the changes in serum CPK levels differed. During treatment with pindolol, 20 of 25 patients showed a 20-760% increase in CPK compared with the pretreatment value. Studies on CPK isoenzymes revealed that the elevation was mainly in the skeletal muscle (MM type), while eight of the 25 patients also showed a slight increase in the myocardial type (MB type). Another beta-blocking agent with intrinsic sympathomimetic activity (ISA), carteolol, also increased the CPK levels significantly in 10 of 15 patients. On the other hand, such increases were observed in only four of 27 patients receiving propranolol and three of nine patients receiving labetalol. These results suggest that beta-blocking agents with ISA increase the serum CPK levels more frequently than those without ISA. Therefore, the serum CPK levels should be carefully evaluated in patients receiving beta-blocking agents, especially those with ISA.

Adrenergic beta-Antagonists↗

Evaluation of floating impeller phenomena in a gyro centrifugal pump.

The Gyro centrifugal pump, developed as a totally implantable artificial heart, was designed with a free impeller in which the rotational shaft (male bearing) of the impeller was completely separated from the female bearing. For this type of pump, it is very important to keep the proper magnet balance (impeller-magnet and actuator-magnet balance) to prevent thrombus formation or bearing wear. When the magnet balance is not proper, the impeller is jerked down into the bottom bearing. On the other hand, if magnet balance is proper, the impeller is lifted off the bottom of the pump housing within a certain range of pumping conditions. In this study, this floating phenomenon was investigated in detail. The floating phenomenon was proven by observation of the impeller behavior by means of a transparent acrylic pump. The impeller floating phenomenon was mapped on a pump performance curve. The impeller floating phenomenon is affected by the magnet-magnet coupling distance and the rotational speed of the impeller. To keep the proper magnet balance and to maintain the impeller floating phenomenon at the driving conditions of right and left pumps, the magnet-magnet coupling distance was altered by a spacer that was installed between the pump and actuator. It became clear that the same pump could handle different conditions (right and left ventricular assist) by changing the thickness of the spacer. When magnet balance is proper, the floating impeller phenomenon occurs automatically in response to the impeller revolution. This is called "the dynamic revolutions per minute suspension."

Centrifugation↗

Validity of microsphere model in cerebral blood flow measurement using N-isopropyl-p-(I-123) iodoamphetamine.

A microsphere model is sometimes used when calculating cerebral blood flow (CBF) using N-isopropyl-p-[I-123]iodoamphetamine (IMP), and is based on the assumption that there is essentially no washout of IMP. The validity of a microsphere model was investigated by comparison with the values of CBF obtained by means of a model which takes into consideration the diffusion of IMP from brain tissue to blood (nonmicrosphere model). When calculating CBF by the latter model, the look-up table method was used with expression of the double integral in the model equation by the recursion relations, a method which is useful for obtaining pixel-by-pixel values. The average rate constants for diffusion from brain to blood of gray and white matter were 0.021 and 0.0016 min-1, respectively. The values of CBF obtained by applying a microsphere model to the data acquired from 0 to 3.2 min after IMP injection were overestimated by approximately 23% compared with those values obtained using a nonmicrosphere model. This is considered to be due to the effect of the IMP activity in the vascular space. Values obtained using the data acquired from 3.2 to 6.4 min were underestimated by approximately 15%. When the values of CBF obtained by a microsphere model were interpolated, they became nearly equal to those obtained using a nonmicrosphere model at about 4 to 5 min after injection. This is suggested to be the reason why the underestimation due to diffusion from brain to blood is cancelled out by the overestimation due to the IMP in the vascular space. Our preliminary results suggest that it is necessary to take the diffusion of IMP from brain tissue to blood into account for the quantification of CBF using IMP.

Amphetamines↗

The storage form of human renal renin.

We isolated renin granules from cadaver kidneys using discontinuous sucrose density gradient centrifugation, and investigated the storage form of the renin from these granules. Approximately 23% of the total renin activity in the original homogenate was obtained from the surface phase between 1.6 and 1.7 M sucrose (Fraction 6). Granule renin extracted from the granules in Fraction 6 was separated into active and inactive renin using pepstatin affinity chromatography. Only the active renin had an affinity for pepstatin. The inactive renin, albeit activated by trypsin, was little activated by acidification. The proportion of inactive renin was about 25% of the total granule renin (active renin + inactive renin). Trypsin concentrations over 10 micrograms/ml resulted in a decrease in the renin activity of the trypsin-activated renin, but the enzymatic activity of active renin was decreased by trypsin. With gel filtration, the inactive renin revealed a single peak, and the molecular weight (MW) was 48,000. The active renin had a MW of 44,000. The inactive renin could be activated by trypsin without an apparent change in molecular weight.

Aged↗

Effects of sodium depletion on inactive and active renin from dog kidney and plasma.

The relationship of active renin and inactive renin (trypsin-activated angiotensin-I-forming enzyme) to sodium depletion was examined in renal and peripheral plasma and at the subcellular level in the kidneys of dogs. Subcellular fractionation was carried out by discontinuous sucrose density (1.5 and 1.6 M) centrifugation. Sodium depletion selectively caused a six- to sevenfold increase in the renal content of inactive and active renins in the original homogenate, while the subcellular distribution patterns of these enzymes were little changed. Of the total granule fractions of 1.5 M sucrose (F1), 1.6 M sucrose (F2), and sediment (F3), approximately 80% of inactive renin was recovered in F1, which was rich in microsomes, while about 50% of active renin was in F2. The ratio of inactive to active renin was 0.02 in F1 and 0.003 to 0.004 in F2. Sodium depletion also caused a 20-fold increase in active renin and a twofold increase in inactive renin in peripheral plasma. The renal venous-arterial concentration difference of inactive renin was statistically significant in low-sodium dogs, although it was not significant in controls. The ratio of inactive to active renin was 0.2 to 0.4 in plasma from low-sodium dogs, while it was 1.5 to 3 in plasma from control dogs. These results suggest that plasma inactive renin originates, at least in part, in the kidney.

Animals↗

Development of a method for embedded-culture of pig pancreatic islet-like cell clusters in agarose containing maltose-carrying polystyrene (HEVM) and nicotinamide.

A method for embedded-culture of islet-like cell clusters (ICCs) from neonatal pig pancreas is described. The procedure is based on a sequential treatment of the pancreas with a proteolytic enzyme and ethylenediaminetetraacetate (EDTA). During the exposure to EDTA-Dispase, small pieces of pancreas were gradually digested, with gentle stirring. Under- and over-digested pancreatic cell clusters were separated from the pancreatic fragments by filtration, and formed whole islet-like cell clusters in RPMI 1640 containing 11.0 mM D-glucose and 10% fetal bovine serum (FBS). The ICCs were embedded in agarose with or without a gel containing a random copolymer hydroxethylmethacrylate-vinylbenzyl maltonamide (HEVM) of hydroxethylmethacrylate-(HEMA)-vinylbenzyl maltonamide (VMA) and nicotinamide. They remained morphologically intact and a physiological response to acute stimulation with glucose was obtained when they were embedded in the agarose containing HEVM and nicotinamide. These findings suggest that ICCs in agarose containing HEVM and nicotinamide could be a useful tool for morphological, biochemical and molecular biological studies, and also as a potential source of material for transplantation.

Animals↗

[Slowly progressive dressing and constructional apraxia: symptomatological study, especially for dressing apraxia].

In 1982, Mesulam drew attention to a clinical picture characterized by slowly progressive aphasia without dementia, and since then, there have been many such reports. Recently, there have been 30 reports of slowly progressive apraxia. However, the nature of this apraxia is not uniform. We now report a patient with slowly progressive dressing and constructional apraxia. The patient is a 60-year-old right-handed woman with a 2-year history of a slowly progressive praxic disturbance. On admission, she was alert and aware of this difficulty. A neurological examination disclosed mild rigidity and myoclonus in her left hand. A neuropsychological assessment disclosed severe dressing apraxia, which was unlikely to be caused by dementia and moderate constructional apraxia. Her dressing apraxia was manifested in upper limbs, neck, trunk and lower limbs. However, she could express verbally the action of dressing. She also showed mild limb-kinetic apraxia, but neither ideational apraxia nor ideomotor apraxia was present. Aphasia and agnosia were also absent. On an MRI, the bilateral cerebral hemispheres were atrophic (right > left). A 99m-Tc ECD SPECT revealed decreased uptake in the right cerebral hemisphere and left frontal lobe, and an EEG showed slow waves over the right cerebral hemisphere. There have been 30 reports of slowly progressive apraxia. Most of these cases presented with slowly progressive clumsiness in one or both hands as an initial symptom, followed by constructional, ideomotor or dressing apraxia. Our patient differed from these cases in that dressing and constructional apraxia progressed slowly without any other apraxia except only mild limb-kinetic apraxia. There was a similarity between dressing apraxia of our patient and that of Marie's and Brain's original cases.

Activities of Daily Living↗

Influence of oral health attitude of mothers on the gingival health of their school age children.

We investigated the influence of mothers' oral health attitudes on their children's gingival health level, in 257 pairs of mothers and children from an elementary school in Hiroshima. The Oral Rating Index for Children (ORI-C) was used for the gingival health examination, and the Hiroshima University Dental Behavioral Inventory (HU-DBI) was used to assess the oral health attitude of each mother. Subjects in mother and child pairs were divided into a lower grade group (L-group) (grades 1-3), and upper grade group (U-group) (grades 4-6). Gingival health i L-group children was 3.42 times higher in those whose mothers noticed plaque, and 2.68 times higher in those who received dental check-ups. However, ORI-C scores were not correlated to HU-DBI scores in the U-group. We concluded that the gingival health of children could be significantly influenced by the oral health attitude of their mothers up to approximately ten years of age.

Age Factors↗

Effect of myocardial revascularization on acute phase of myocardial infacrtion. Macroscopic, histological and electrocardiographic data.

The purpose of this study was to investigate the time during which the emergency reconstruction of the occluded coronary artery is most effective. This problem was examined from the viewpoint of the extent of reversibility of the damage to ischemic myocardial muscle, by using forty nine mongrel dogs. The surgical reconstruction of the occluded coronary artery within 6 hours after the onset of myocardial infarction was most effective. In such cases, the extent of myocardial infarction remained small in size, and the healing of necrotic myocardial muscle was hastened. Thus, the development of cardiac failure was well protected.

Acute Disease↗

Treatment response on CT scan in patients with brain metastases treated with irradiation.

To evaluate the role of CT scans in the assessment of response to therapeutic irradiation of brain metastases, CT findings of 64 patients were reviewed retrospectively. Enhanced tumor on CT scans disappeared in 21 patients, who survived significantly longer than those whose CT scans showed less than 50% regression (p less than 0.01). Ring contrast enhancement (ring CE) of the tumor on pre-RT CT scan did not seem to affect the patient's prognosis for survival. Tumors with ring-CE on pre- and post-RT CT scans, however, did not regress as much as those without ring-CE. Patients without ring-CE on pre- and post-RT CT scans tended to survive longer than those with ring-CE. This study suggests that tumor regression and the CE pattern on pre- and post-RT CT scans would be useful prognostic indicators for patients with brain metastases.

Aged↗

A septum-like structure of the gallbladder in acute viral hepatitis: CT demonstration.

We present two patients with a septum-like structure of the gallbladder on CT. The patients were hospitalized with acute viral hepatitis. CT performed within a week from the onset of symptoms demonstrated a high density linear structure in the gallbladder mimicking a septum. This structure seemed to be produced by a marked thickening of the gallbladder wall. It disappeared during the clinical recovery.

Acute Disease↗

Gallium-67 citrate scintigraphy in Wegener's granulomatosis involving the stomach.

67Ga-citrate scintigraphy was performed on a 68-year-old woman with Wegener's granulomatosis of the right orbita and nasal cavity to search for other involved sites. Seventy-two-hour images demonstrated an abnormal accumulation on the left upper abdomen, in addition to her head and chest. Upper gastrointestinal series revealed marked deformation of the upper part of the stomach and a large shallow ulcer on its posterior wall. The histological diagnosis from biopsied specimens on gastroendoscopy was an involvement of Wegener's granulomatosis. 67Ga-citrate scintigraphy was helpful in detecting the sites of involvements of this disease.

Aged↗

Serological and pathological studies of Newcastle disease viruses isolated from caged birds from Southeast Asia.

Eleven isolates of Newcastle disease virus (NDV), from caged birds imported from or captured in Southeast Asia in 1979-80, were antigenically divided into five distinct groups. Most of them were distinguishable from more classical NDVs (vaccine B1 strain and Miyadera strain) on the basis of their reactivity to eight monoclonal antibodies against the HN molecule of NDV in hemagglutination-inhibition tests. However, when three representative isolates were evaluated for their biological properties and pathogenicity against 1-day-old chickens, all three were found to be velogenic types that could induce serious symptoms of Newcastle disease and which eventually killed all of the chickens, regardless of the route of infection. There was not any significant correlation between their reactivity patterns with the monoclonal antibodies and their virulence.

Animals↗

Carcinoma of the esophagus simulating "downhill" varices.

A case of esophageal carcinoma which showed an upper mediastinal mass shadow on plain chest X-ray film and varicoid lesions on esophagogram is reported. The findings seemed compatible with "downhill" varices, an unusual form of esophageal varices caused by superior vena caval obstruction. In this case, contrast-enhanced computed tomography (CE-CT) was useful for the differential diagnosis between varices and varicoid tumor.

Carcinoma↗

Effect of increased oxygen on peripheral circulation in acute, temporary limb hypoxia.

This study was intended to investigate the effect of high arterial oxygen tension on the peripheral circulation between normal and hypoxic area by using twelve dogs. For this purpose, acute temporary ischemia was produced at the right hindlimb by an occlusion of the right external iliac artery for 1 and 2 hours, and the left hind-limb was let alone as a control. The peripheral vascular resistance and the arterio-venous difference in oxygen tension between the right and the left hind-limb were measured continuously during 1 hour from immediately after reopening of the blood flow of the right external iliac artery. They were compared between at the condition of breathing room air at 1 ATA and pure oxygen at 2 ATA. The high arterial oxygen tension causes vasoconstriction. When there exists hypoxia in the peripheral tissue, however, it does not act on as a vasoconstrictive factor until the oxygen deficit is improved.

Animals↗

Scintigraphic study on the distribution of radiolabeled cis-diamminedichloroplatinum (II) in the tumor-bearing rabbit: a comparison between intra-arterial injection with lipiodol and intravenous injection.

To compare the distribution of cis-diamminedichloroplatinum (II) (CDDP) on scintigraphic images between intra-arterial injection with lipiodol and intravenous injection, we obtained serial scintigraphic images using radiolabeled CDDP (Pt-195m CDDP), which had a high specific activity (7.4 x 10(6) Bq [200 microCi]/mg-CDDP), in the rabbit VX-2 tumor system. A dose of 9.25 x 10(6) Bq (250 microCi) of Pt-195m CDDP was injected at one shot via an ear vein, while 7.4 x 10(6) Bq (200 microCi of Pt-195m CDDP mixed with 1 ml of lipiodol was injected at one shot via a saphenous artery. Mean pixel count, which was corrected for the total dose injected, in the arterially injected tumor always exceeded than that in the intravenously injected tumor. Pt-195m CDDP uptake by the rabbit tumor at 2 hr was 7.8% of the total injected dose with intravenous injection and 16.0% with intra-arterial injection. These data suggest that intra-arterial injection with lipiodol is a more useful method to increase CDDP uptake by tumors than intra-venous injection.

Animals↗