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Biomedical subjects

T Kamada

Publications and source records attributed to T Kamada.

At least 541 records · Page 30Linked to original sources
PubMed1991

[Reservoir system implantation technique via the inferior epigastric artery].

A reverse application technique of the radiofocus guidewire, as a guide for arterial cut down approach, was employed for the implantation of the reservoir system via inferior epigastric artery. Twenty five of the 26 patients succeeded in the implantation of reservoir system with this method, including two patients who were implanted two systems simultaneously. The advantages of this technique are as follows. Under the fluoroscopic examination, it is easy and safe to insert the catheter. There is no observation of the catheter dislocation, because the catheter does not get through the inguinal ligament. Two reservoir systems can be implanted simultaneously. This technique can be carried out immediately after the conventional angiography. With this technique, a high selective insertion rate (96%) of the catheter was achieved without no complication. This technique is feasible in implanting the reservoir system, but it is advisable for further studies to be made in order to clarify indications and further complications.

Adult↗
PubMed1991

Expression of X protein and hepatitis B virus replication in chronic hepatitis.

The X protein can act on the enhancer of hepatitis B virus in an in vitro system and elevate the transcriptional level of hepatitis B virus. However, because no relationship had been reported between X protein expression and hepatitis B virus replication in patients with chronic hepatitis B, we focused on its expression in the liver in comparison with markers of hepatitis B virus replication. Liver biopsy samples and sera from 59 carriers with HBsAg were examined immunohistochemically for X protein using rabbit IgG against recombinant X protein. There was a significant difference in the serum hepatitis B virus DNA level between X protein-positive and -negative patients (p less than 0.001). Serum pre-S1 and pre-S2 antigens were also measured quantitatively by enzyme immunoassay using monoclonal antibodies specific against each antigen. The titers of pre-S1 antigen in patients positive for X protein were significantly higher (p less than 0.001) than those of the X protein-negative patients (3.02 +/- 0.99 vs. 2.00 +/- 0.59, respectively). Similarly, the titers of pre-S2 antigen were 2.98 +/- 0.91 vs. 1.94 +/- 0.54, respectively (p less than 0.001). The rate of positivity of the X protein was higher (38 of 49; 77.6%) in the replicative group (serum HBeAg, serum hepatitis B virus DNA or HBcAg in liver positive) compared with that observed in the nonreplicative group (3 of 10; 30%--serum HBeAg, serum hepatitis B virus DNA and HBcAg in liver negative) (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

A clinical study of acute gastrointestinal hemorrhage associated with various shock states.

Gastrointestinal hemorrhage from stress ulceration is a life-threatening complication in a critically ill patient. We retrospectively studied 471 patients admitted to the Department of Traumatology of our hospital who developed shock in their clinical course. Forty-two patients (8.9%) developed gastrointestinal hemorrhage, most within 1 wk (76.2%). The hemorrhage lesion usually was located in the corpus of the stomach. The mortality rate of the shock patients with gastrointestinal hemorrhage was 33.3% (14 of 42). Comparison of different types of shock showed that the incidence, severity, and mortality rates of gastrointestinal hemorrhage were significantly higher in septic shock patients than in hemorrhagic shock patients. These findings show the importance of preventive therapy against progression of early mucosal damage and development of gastrointestinal hemorrhage in shock patients, especially those with sepsis.

Acute Disease↗
PubMed1991

[Clinical significance of I-123 MIBG myocardial scintigraphy for evaluating the severity of congestive heart failure].

We studied the significance of I-123 MIBG (metaiodobenzylguanidine) myocardial scintigraphy for evaluating the severity of congestive heart failure. I-123 MIBG scintigraphy was performed in 7 patients with congestive heart failure (CHF) of NYHA class I-III (6 with dilated cardiomyopathy and 1 with Adriamycine cardiomyopathy) and in 2 normals. The SPECT and anterior planar myocardial images were obtained 15 minutes after (initial images) and 4 hours after (delayed images) an injection of I-123 MIBG (111 MBq). Compared with normals, patients with CHF demonstrated (1) low myocardial uptake and (2) rapid myocardial washout of I-123 MIBG, indicating myocardial sympathetic disarrangement. Then, quantitating these abnormalities with the heart to upper mediastinum uptake ratio (H/B) and the percent washout rate (%WR) during 4 hours, respectively, we compared these two indices with LV ejection fraction (EF) at rest measured by echocardiography and exercise capacity (max VO2 and VO2 at anaerobic threshold (AT] determined with respiratory gas exchange analysis during maximal bicycle exercise. H/B was lower and %WR was greater in patients with CHF than in normals. H/B correlated with EF (r = 0.77, p less than 0.05) and AT (r = 0.74, p less than 0.05). On the other hand, %WR significantly correlated with EF (r = 0.79, p less than 0.05), max VO2 (r = -0.74, p less than 0.05) and AT (r = -0.81, p less than 0.05). Thus, H/B and %WR were closely related to the severity of CHF. These results suggest that I-123 MIBG myocardial scintigraphy and the quantitative analysis of I-123 MIBG myocardial uptake provide useful information about the severity of CHF.

3-Iodobenzylguanidine↗
PubMed1990

Platelet production, clearance and distribution in patients with idiopathic thrombocytopenic purpura.

Platelet destruction mechanism was thought to play a primary role in autoimmune thrombocytopenia (ITP). There is, however, some evidence that anti-platelet antibodies in ITP impair megakaryocytopoiesis. Using autologous In-111 platelets, we tried to elucidate this point. We measured platelet survival, platelet turnover, platelet sequestration sites, and platelet production (turnover) to the clearance (sum of liver and spleen platelet uptake) ratio in 8 normal subjects and 12 patients with ITP whose platelet counts ranged from 9 x 10(9) to 40 x 10(9)/L. The sum of platelet uptake in the liver and spleen showed a significant inverse correlation with platelet survival. Platelet survival, platelet production to clearance ratio correlated significantly with the platelet count. No significant correlation was found between platelet turnover and platelet counts. The distribution of platelet turnover showed considerable individual variation; 8 of 12 patients showed platelet turnovers which were lower than the normal value, but the others were within the normal range. We concluded that although the platelet destruction mechanism in the reticuloendothelial system shows a primary role in thrombocytopenia, the impaired rate of effective thrombopoiesis may also contribute to the severity of ITP.

Adult↗
PubMed1990

Auditory response properties and directional sensitivity of cerebellar neurons of the echolocating bat, Eptesicus fuscus.

Auditory response properties and directional sensitivity of cerebellar neurons of Eptesicus fuscus were studied under free-field stimulation conditions. The best frequency (BF) and minimum threshold (MT) of a recorded neuron were first determined with a sound delivered in front of the bat. Discharge pattern and MT were studied with both BF stimuli and one-octave downward and upward sweep FM (frequency-modulated) stimuli. The directional sensitivity of cerebellar neurons was then studied by determining the variation of MT and response latency with BF and FM stimuli broadcast from each of 15 loudspeakers attached to a semicircular wooden track in front of the bat. All 85 cerebellar neurons recorded discharged phasically to acoustic stimuli. Only 20 were spontaneously active. Cerebellar neurons were generally more sensitive to FM stimuli than to pure tone pulses. Thus, they discharged more vigorously and had a lower MT to the former than the latter stimulus. Directional sensitivity of 47 neurons (BF = 23.4-81.1 kHz) was studied. All neurons varied their MTs with sound direction. Most neurons (n = 37, 79%) showed a lowest MT to a frontal sound. Directional sensitivity of cerebellar neurons appears to be sharper when determined with BF tone pulses than with FM stimuli. Thus the directional slope and the difference in MT between the best and worst angles of these neurons were larger when determined with the BF stimulus. Directional sensitivity of cerebellar neurons is not dependent upon stimulus frequency, unlike that of the inferior and cortical neurons of the same bat. Cerebellar neurons also varied their response latency with sound direction. Such a variation may provide the bat with another neural code for sound localization.

Animals↗
PubMed1990

Alpha 1-adrenoceptor stimulation increases intracellular pH and Ca2+ in cardiomyocytes through Na+/H+ and Na+/Ca2+ exchange.

The effects of alpha 1-adrenergic stimulation on intracellular pH (pHi) and Ca2+ concentration ([Ca2+]i) were investigated in isolated rat cardiomyocytes with fluorescence dyes, BCECF and fura-2, respectively. In the presence of 5 or 25 mM HCO3- norepinephrine (NE) increased pHi in a dose-dependent manner. Intracellular alkalinization was inhibited by prazosin and phentolamine but not by yohimbine. NE-induced alkalinization was inhibited in the presence of a Na+/H+ exchange inhibitor (5-(N,N-hexamethylene) amiloride (HMA)), a C kinase inhibitor (H-7) or a calmodulin inhibitor (W-7), or in the absence of extracellular Na+. NE also increased [Ca2+]i following the pHi increase, which was abolished in the absence of extracellular Na+ or Ca2+. This Ca2+ influx was inhibited by HMA but not by diltiazem (10(-5) M). Thus, we conclude that alpha 1-adrenergic stimulation enhances Na+/H+ exchange by activation of C kinase, thereby allowing intracellular alkalinization, and that subsequent activation of Na+/Ca2+ exchange increases Ca2+ influx.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1990

Coronary collaterals assessed with myocardial contrast echocardiography in healed myocardial infarction.

The epicardial coronary collateral vessels are visualized with coronary angiography, but this method does not provide significant information about the myocardial perfusion supplied with the collaterals. In this study, myocardial contrast echocardiography (MCE) was performed to assess the coronary collaterals in 29 patients with old myocardial infarction. MCE was performed by intracoronary injection of 2 ml agitated amidotrizoate sodium meglumine. The peak background-subtracted gray level (PGL) in the infarct area was determined from the digitized echocardiographic images obtained before and after injection into the noninfarct and donor artery. PGL was compared with the 3-point coronary angiographic grades of collaterals. PGL in the infarct area was significantly lower in patients with poor collaterals than in patients with moderate to good collaterals (5 +/- 4 vs 18 +/- 8 U mean +/- standard deviation, p less than 0.01). PGL in the infarct area was less than 10 U in the 3 patients with severe asynergy despite the moderate to good collateral supply, suggesting that activity of the collaterals was not good enough to preserve the wall motion effectively. It is concluded that (1) the degree of MCE enhancement in the infarct area generally corresponded to the collateral grades assessed with coronary angiography, and (2) MCE may provide a measure of the collateral perfusion.

Adult↗
PubMed1990

[Radiotherapy of carcinoma of the uterine cervix--high dose rate intracavitary irradiation using a linear source arrangement].

We analyzed the records of 339 patients with squamous cell carcinoma of the uterine cervix. The patients were treated by irradiation alone in the period of 1973-1985 with external and high-dose rate intracavitary irradiation using linear source arrangement. The reason for using the linear source arrangement was to ensure the position of source as well as to simplify the technique of intracavitary irradiation. First, external irradiation was performed mainly with a dosage of 50Gy/25f four times a week or 50.4Gy/28f five times a week. Intracavitary irradiation was then carried out mainly with a dose of 30Gy/6f two times a week or 35Gy/7f two times a week and dose was indicated at point A. The 5-year survival rate of all 330 patients were 51.4%, and 55.1% for stage I (N = 19), 66.7% for stage II (N = 88), 47.1% for stage III (N = 212), 33.7% for stage IV (N = 20). Of the patients followed up for 24 months and found to have recurrence, 21.8% (39/179) had a recurrence in the pelvis and 22.1% (39/175) were found to have a distant metastasis. Of the patients followed up for over 24 months, 21.5% 932/149) developed intestinal complications and 12.2% (18/149) developed bladder complications. However complications Grade 2-4 were 5.4% for intestinal complications and 2.0% for bladder complications. From these results high-dose-rate intracavitary irradiation using a linear source arrangement was considered to be an effective treatment of carcinoma of the uterine cervix and to produce a standard results of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Transport of glutathione across the mitochondrial membranes.

Transport of glutathione (GSH) into mitochondria was observed when mitochondria in state 4 respiration were incubated with high concentrations of GSH. This transport was suppressed by antimycin A or dicyclohexyl-carbodiimide, or in state 3 respiration. Upon dissipation of the proton gradient by a proton ionophore, mitochondrial GSH was released into the medium. GSH moved freely across the proton-permeated mitochondrial membrane, its movement depending only on the GSH gradient across the inner membrane. These results indicate that there is a transport system for GSH in the mitochondrial membrane, and that a proton gradient is necessary to maintain GSH in the matrix, and to transport GSH into mitochondria.

Animals↗
PubMed1990

Quantitative analysis of pre-S1 and pre-S2 in relation to HBsAg expression.

Sera from four patients with acute hepatitis B and 87 patients with chronic hepatitis B were examined quantitatively for pre-S1 and pre-S2 antigens by solid-phase enzyme immunoassays. Pre-S1 and pre-S2 antigens were detected in HBsAg-positive sera irrespective of the presence of viral replicative markers, and their titers correlated with those of HBsAg (r = 0.74, p less than 0.01; r = 0.74, p less than 0.01, respectively). Sera positive for HBeAg showed higher titers of pre-S1 (p less than 0.01) and pre-S2 (p less than 0.01) antigens than sera negative for HBeAg. The titers of pre-S1 and pre-S2 antigens also correlated with the levels of HBV-associated DNA polymerase activity (r = 0.51, p less than 0.01; r = 0.59, p less than 0.01, respectively) and HBV-DNA (r = 0.50, p less than 0.01; r = 0.46, p less than 0.01, respectively). However, the ratios between the titers of pre-S antigens and HBsAg had no significant relationships with those viral replicative markers. These findings suggest that the expression of pre-S antigens is intimately related to the expression of HBsAg and that they are not useful as markers of viral replication. The ratios between the titers of pre-S antigens and HBsAg tended to be high in patients with chronic active hepatitis and high aminotransferase levels. This finding may have been due to the hepatic release of pre-S antigens, over-production of which may have some relationship to liver injury.

Acute Disease↗
PubMed1990

Detection of antibodies against the polymerase gene product in hepatitis B virus infection.

We have studied antibodies (anti-pol antibody) against the polymerase gene product of hepatitis B virus by solid-phase enzyme immunoassay using synthetic peptides coded for by this gene. Sera from six patients with acute hepatitis B, 112 chronic hepatitis B virus carriers and six healthy individuals with naturally acquired immunity to hepatitis B virus were tested for anti-pol antibody. In acute hepatitis B virus infection, anti-pol antibody was detected in three of six patients. In chronic hepatitis B virus infection, anti-pol antibody was detected in 17 of 29 (59%), in 23 of 33 (70%) of cirrhotic patients and in 18 of 24 (75%) patients with cirrhosis complicated by hepatocellular carcinoma, compared with 4 of 19 (21%) asymptomatic carriers and 2 of 7 (29%) patients with chronic persistent hepatitis. Titers of anti-pol antibody were higher in cirrhotic patients with and without hepatocellular carcinoma than in patients with chronic active hepatitis. The presence of anti-pol antibody, however, had no relationship with hepatitis B virus-associated DNA polymerase activities and other viral replicative markers. As for sera from six healthy individuals with naturally acquired immunity to hepatitis B virus, two (33%) were positive for anti-pol antibody. These results indicate that the immune response toward the polymerase gene product is induced during acute and chronic hepatitis B virus infection. In chronic hepatitis B virus infection, anti-pol antibody may serve as a new marker indicative of a long period of hepatitis B virus-induced hepatitis.

Acute Disease↗
PubMed1990

A rapid turbidimetric immunoassay for serum antistreptolysin-O.

We designed a rapid, quantitative turbidimetric immunoassay for serum antistreptolysin-O (ASO), based on the immunoprecipitating velocity with purified streptolysin-O (SLO), which can be measured turbidimetrically at 340 nm. The assay system involves polyoxyethylene mono-p-nonylphenyl ether to accelerate and enhance the immunoprecipitation reaction. No antibody excess phenomenon is observed, up to 1,700 U/ml. Grossly icteric sera can be assayed. Patient sera gave acceptable results. Free cholesterol offers no interference. The standard curve is linear for values up to 800 U/ml. Results measured by the proposed method and those by the conventional microtitration method correlated well. Analytical recovery averaged 90.1% (80.3%-102.5%). Within-run and day-to-day CVs ranged from 2.1% to 3.5% and from 2.5% to 6.9%, respectively. Working SLO is stable for at least 15 days at 4 degrees C. The proposed method has proven to be superior to other available methods for measuring serum ASO.

Antistreptolysin↗
PubMed1990

Effect of ethanol on hepatic oxygenation: evidence of hepatic hypoxia.

The effects of low (1 g/kg body wt) and high doses (4 g/kg body wt) of ethanol on hepatic oxygenation in rats was investigated employing an in vivo microscopic and spectrophotometric system and also a micro oxygen electrode. The low dose of ethanol increased sinusoidal blood hemoglobin oxygenation (ISO2) at periportal regions in the liver lobule. The high dose of ethanol increased ISO2 at periportal regions, but decreased ISO2 at pericentral regions. The low dose of ethanol increased hepatic surface tissue PO2, but the high dose decreased this PO2. From these data it is concluded that the increase of hepatic blood flow, after administration of a low dose of ethanol, compensated for the increase of oxygen demand in hepatocytes but that administration of a high dose of ethanol reduced hepatic tissue oxygenation via an imbalance between delivery and demand of oxygen in pericentral regions of the liver lobule, resulting in local hypoxia in surface hepatic tissue.

Animals↗
PubMed1990

Frequency and space representation in the inferior colliculus of the FM bat, Eptesicus fuscus.

The tonotopic organization and spatial sensitivity of 217 inferior collicular (IC) neurons of Eptesicus fuscus were studied under free field stimulation conditions. Acoustic stimuli were delivered from a loudspeaker placed 21 cm ahead of the bat to determine the best frequency (BF) and minimum threshold (MT) of isolated IC neurons. A BF stimulus was then delivered as the loudspeaker was moved horizontally across the frontal auditory space of the bat to locate the best azimuthal angle (BAZ) at which the neuron had its lowest MT. The stimulus was then raised 3 dB above the lowest MT to determine the horizontal extent of the auditory space within which a sound could elicit responses from the neurons. This was done by moving the loudspeaker laterally at every 5 degrees or 10 degrees until the neuron failed to respond. These measurements also allowed us to redetermine the BAZ at which the neuron fired maximal number of impulses. Electrodes were placed evenly across the whole IC surface and IC neurons were sampled as many as possible within each electrode penetration. Tonotopic organization and spatial sensitivity were examined among all 217 IC neurons as a whole as well as among IC neurons sequentially sampled within individual electrode penetrations. The whole population of 217 IC neurons is organized tonotopically along the dorsoventral axis of the IC. Thus, low frequency neurons are mostly located dorsally and high frequency neurons ventrally with median frequency neurons intervening in between. The BAZ of these 217 IC neurons tend to shift from lateral to medial portions of the contralateral frontal auditory space with increasing BF.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗
PubMed1990

Effects of endoscopic variceal sclerotherapy using GT XIII on blood coagulation tests and the renal kallikrein-kinin system.

Forty-six sclerotherapy sessions were performed on liver cirrhotics with high-risk esophageal varices using GT XIII, a sclerosant composed of gelatin, thrombin and coagulation factor XIII. GT XIII was effective for the prevention of temporary symptoms and transient hypotension observed in 55 sclerotherapy sessions using thrombin. In 42 (91%) sessions, patients underwent sclerotherapy with no symptoms, and in the other four (9%) sessions, only slight symptoms of general fatigue and headache were observed. Changes in the mean arterial pressure were significantly smaller in sessions using GT XIII than in those using thrombin (-12.3 +/- 13.6 vs. -26.8 +/- 20.7 mmHg, P less than 0.01). Changes in coagulation tests, similar to those of disseminated intravascular coagulation (DIC), were also reduced in sessions using GT XIII. Urinary kallikrein and kinin excretion significantly increased after the procedure (P less than 0.01), indicating activation of the renal kallikrein-kinin system. Increases in urinary kallikrein and kinin excretion showed a significant relationship with the consumed plasma fibrinogen levels (r = -0.51, P less than 0.01 and r = -0.58, P less than 0.01, respectively), and it was suggested that activation of the glandular kallikrein-kinin system caused by abrupt DIC-like changes in the hemostatic system might play a role in manifestations of temporary complications occurring with the use of hemostatic agents containing thrombin.

Blood Coagulation↗