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Biomedical subjects

T Shiga

Publications and source records attributed to T Shiga.

At least 181 records · Page 10Linked to original sources
PubMed1989

Neuronal organization of the supracommissural ventral telencephalon and the nucleus preopticus periventricularis in the himé salmon (landlocked red salmon, Oncorhynchus nerka): a Golgi study.

The neuronal organization of the supracommissural ventral telencephalon (Vs) and the nucleus preopticus periventricularis (NPP) of the medial preoptic area (MPOA) in the himé salmon (landlocked red salmon, Oncorhynchus nerka) was studied by means of the Nissl staining and the rapid Golgi methods. The Vs was composed of many laterally-orienting spiny neurons and a few sparsely-spined polymorphous neurons. Some of the laterally-orienting neurons extended their dendrites into the lateral forebrain bundle (LFB), suggesting that they may receive inputs from the telencephalofugal and telencephalopetal fibers in the LFB. The NPP consisted of five types of sparsely-spined neurons: laterally-orienting, bipolar, cerebrospinal fluid (CSF)-contacting, commissural, and multipolar neurons. Some of the laterally-orienting neurons extended their dendrites into the medial forebrain bundle (MFB) and regions near the LFB, suggesting that they may also receive inputs from the telencephalofugal and telencephalopetal fibers running there. The presence of the CSF-contacting neurons in the NPP suggests that the NPP may receive humoral informations from the CSF. Involvement of these CSF-contacting neurons in the control of the reproductive functions was discussed. The neuronal organization of the NPP in the himé salmon was compared with that of the MPOA in other vertebrates.

Animals↗
PubMed1989

[New approach for unresectable primary liver cancer--intra-arterial combination chemotherapy during and after operation with local injection of ethanol].

From 1976 to 1988, hepatic arterial infusion chemotherapy was performed in 52 patients with unresectable hepato-cellular carcinomas. Forty-nine (94%) out of 52 patients were stage III or stage IV. Thirty-five patients underwent continuous infusion of 5-FU and MMC employing chronometric infusion pumps. Mean survival of this group was 9 months. Six patients survived more than 12 months; the longest survivor died of different causes 40 months after surgery. Another patient lived for 30 months. In 10 patients, hepatic arterial ligation was performed in combination with infusion chemotherapy in the hepatic artery. Mean survival of these patients was 14 months. Four out of the 10 patients survived over 12 months. Recently, in 7 patients whose liver tumors were less than 4 cm in diameter and/or whose tumors were multiple and had liver disfunction, ethanol injection into the tumors during laparotomy was performed in combination with hepatic arterial infusion chemotherapy. In these 7 patients, an injection port system was implanted subcutaneously for intermittent infusion chemotherapy of MMC + 5-FU and ADM + lipiodol. Mean survival in this group was 14 months. One of 7 patients died 21 months after operation, but the others are alive at this writing. Five of these 6 patients have survived more than 12 months. AFP levels decreased in 3 patients after these treatments. In one case, AFP decreased to normal range for 18 months. These results suggested that intraoperative ethanol injection therapy into the tumors combining with hepatic arterial infusion chemotherapy may be of value for unresectable smaller liver carcinomas, since this method is technically easy and can assure injection of ethanol into the tumors during laparotomy.

Aged↗
PubMed1989

[An anesthetic experience with a patient with ornithine transcarbamylase deficiency].

We report an anesthetic experience with ornithine transcarbamylase deficiency. The patient was 26 years of age who underwent open biopsy of the liver for a definitive diagnosis. OTC deficiency is an X-linked disorder of urea cycle. One of the anesthetic problems is how to control the blood ammonia level resulting in neurological damage which occurs following anesthesia and surgery. Recently it has been advocated that benzoate is effective to prevent hyperammonemia in patients with OTC deficiency. As patients with this disease are frequently complicated with hepatic dysfunction, anesthetics which may cause hepatic damage such as halothane should be avoided.

Adult↗
PubMed1989

[Therapeutic effect of interferon-alpha on hairy cell leukemia].

Hairy cell leukemia (HCL) is characterized by slow proliferation of special mononuclear cells. Although splenectomy has been evaluated to be the most effective traditional treatment for HCL, the response of patients to splenectomy is not necessarily satisfactory. Recently, the treatment of HCL with Interferon-alpha has been reported to be effective, and we report a female case of HCL who showed marked improvement in her hematological findings with this therapy.

Aged↗
PubMed1988

Erythrocyte aggregation as a determinant of blood flow: effect of pH, temperature and osmotic pressure.

The effect of pH, temperature and osmotic pressure on velocity of erythrocyte aggregation was quantitatively examined with a rheoscope combined with a video-camera, an image analyzer and a computer, (a) in an artificial medium containing fibrinogen and albumin and (b) in diluted autologous plasma. (1) With increasing pH of the medium, the velocity of erythrocyte aggregation increased. (2) The velocity of erythrocyte aggregation in the artificial medium increased as the temperature rose. However, in 70% autologous plasma the velocity was minimum at 15-18 degrees C, increasing both above and below this temperature (above 30 degrees C, the velocity saturated). (3) The velocity of erythrocyte aggregation decreased in hypotonic medium, while it increased in hypertonic medium (at osmotic pressures higher than 400 mOsm, the velocity decreased). The mechanism of erythrocyte aggregation is discussed with special reference to the morphological changes produced by pH, temperature and osmotic pressure, and the implications of the phenomena for oxygen transport to tissues in (patho)physiological situations are considered.

Adult↗
PubMed1988

Effect of pH on the velocity of erythrocyte aggregation.

The effect of pH on the velocity of aggregation of human erythrocytes was quantitatively examined with a rheoscope combined with a video-camera, an image analyzer and a computer, in relation to the morphological changes of erythrocytes and their aggregates. (i) With increasing pH of the medium, the velocity of erythrocyte aggregation increased. (ii) The rouleaux formed at high pH were longer in shape and more stable against the increase of shear rate than those formed at low pH. (iii) With increasing pH, the diameter of erythrocyte increased, the (maximum) thickness decreased, and the cell volume decreased. The pH dependency of erythrocyte aggregation may be mainly due to the morphological change of erythrocytes, and partly due to the changes of erythrocyte deformability and of interaction with macromolecules.

Erythrocyte Aggregation↗
PubMed1988

Oscillatory deformation of human erythrocytes in sinusoidally modulated shear flow.

The red cell deformation under oscillatory shear stress was studied. Shear stress was sinusoidally modulated between 8 and 32 dyn/cm2, thus, the extent of cellular deformation altered sinusoidally. At a low modulation frequency (less than 1.8 Hz), intact red cells perfectly responded to the shear stress applied on cells, and they could deform as much as the deformation in stationary shear flow. Above 2 Hz, the cellular deformation could not follow changes in shear stress along up-phase in the shear stress cycle. As decreasing the intracellular hemoglobin concentration, the cellular response to oscillatory shear stress became better. Treatment of cells with low concentrations of diamide impaired the response of intact cells to oscillatory shear stress, but unaffected the response of partially hemolyzed cells. These data suggest that the cellular response to oscillatory shear stress is determined by the cytoskeletal structure and the intracellular viscosity.

Blood Viscosity↗
PubMed1988

Human pharmacological investigation of a human recombinant tumor necrosis factor preparation (PAC-4D) a phase-I trial.

15 patients aged between 24 and 66 years with 10 different malignant tumor diseases were treated with a recombinant human tumor necrosis factor preparation PAC-4D in a phase-I trial. The starting dose was 10(5) U PAC-4D as an intravenous short infusion. The maximally tolerable dose is around 18 X 10(5) U/m2. As the main clinical side effects were observed: fever, chills, hypertension with subsequent hypotension, lethargy, transient somnolence, headache, neurological deficiency symptoms, nausea and vomiting. Important laboratory-chemical parameters were the increase in transaminases and, in higher dose levels, leukocytosis with the left shift and lymphopenia in the differential blood picture. As dose-limiting toxicity are estimated hypotension, and neurological side effects and hepatotoxicity. In one female patient who received 27 X 10(5) U PAC-4D there appeared pronounced, histologically verified necroses in the metastases of a malignant fibrous histiocytoma.

Adult↗
PubMed1988

Distribution of erythrocyte in a model vessel exposed to inhomogeneous magnetic fields.

In order to investigate magnetic field effects on blood flow, changes in the flow of erythrocytes in a model branched vessel were observed in an inhomogeneous magnetic field. The magnetic field was applied perpendicular to the straight vessel before branching. When the suspension containing paramagnetic erythrocytes with high spin methemoglobin or deoxygenated hemoglobin flowed in the model vessel, the erythrocytes were attracted towards the stronger magnetic field (i.e. to the side branch) and an excess flow of erythrocytes to the side branch was detected. This excess flow of erythrocytes to the side branch was the highest at a hematocrit of about 5% for the suspension containing erythrocytes with high spin methemoglobin. In the case of mixed suspensions containing erythrocytes with high spin methemoglobin and oxygenated erythrocytes, the excess flow of erythrocytes to the side branch reached its maximum at the "partial hematocrit" for the paramagnetic erythrocyte of around 5% and remained nearly constant with a further increase of the "partial hematocrit." The effect of magnetic field decreased as the flow velocity increased. These results are explained with the paramagnetism of erythrocytes and with the assumption of a hydrodynamic interaction among erythrocytes which are pulled in the direction of the magnetic field. It is suggested that a strong inhomogeneous magnetic field is not totally negligible to the blood circulation.

Blood Circulation↗
PubMed1987

Effect of temperature on the velocity of erythrocyte aggregation.

The velocity of the aggregation of human erythrocytes was examined in the range of 5-43 degrees C with a rheoscope combined with a video camera, an image analyzer and a computer. (1) With increasing temperature, the velocity of erythrocyte aggregation induced by fibrinogen, immunoglobulin G and artificial macromolecules (dextran of 70 kDa and poly(glutamic acid) of 50 kDa) increased. However, the relationship between the velocity of erythrocyte aggregation and the temperature was different among these macromolecules. (2) In 70% autologous plasma, the velocity of erythrocyte aggregation was minimum at 15-18 degrees C, and increased at both higher and lower temperatures. (3) The shape of erythrocyte aggregates in 12 mumol/l fibrinogen (containing 770 mumol/l albumin) and in 70% autologous plasma was dependent on temperature: three-dimensional below 15-18 degrees C and one-dimensional (mainly rouleaux) above 15-18 degrees C. However, the shape of aggregates in 27 mumol/l immunoglobulin G (containing 770 mumol/l albumin) was three-dimensional in all temperature ranges. (4) The temperature dependency of erythrocyte aggregation was discussed in terms of the changes of medium viscosity, of erythrocyte properties and of bridging macromolecules.

Adult↗
PubMed1987

Fibrinogen-induced erythrocyte aggregation: erythrocyte-binding site in the fibrinogen molecule.

The effect of fibrinogen and fibrinogen-derived products on the velocity of rouleau formation of human erythrocytes was quantitatively examined with a rheoscope combined with a video-camera, an image analyzer and a computer. (i) The velocity of rouleau formation by naturally occurring low-molecular-weight fibrinogen of 305 kDa and by desialylated fibrinogen was the same as that by native fibrinogen of 340 kDa. (ii) Concerning fibrinogen degradation products by plasmin, the velocity of rouleau formation decreased upon going from fibrinogen greater than fragment X greater than fragment Y (the ratio of molar concentration of fibrinogen, fragment X and fragment Y for giving a certain velocity of rouleau formation was approx. 1:2:5). The effect of fragments X and Y on the fibrinogen-induced rouleau formation was additive. (iii) Fragments D and E could not induce rouleau formation and did not affect the fibrinogen-, fragment X- and fragment Y-induced rouleau formation. (iv) Fibrinopeptides A and B and artificial tetrapeptides (Gly-Pro-Arg-Pro and Gly-His-Arg-Pro) did not affect the fibrinogen-induced rouleau formation. (v) The possible erythrocyte-binding site in fibrinogen molecule for leading to rouleaux was proposed to be in A alpha-chain (probably, around residues No. 207-303) near the terminal domain of the trinodular structure of fibrinogen.

Binding Sites↗
PubMed1987

Effects of an inhomogeneous magnetic field on flowing erythrocytes.

Effects of an inhomogeneous magnetic field on narrow erythrocyte streams in a wide and transparent laminar buffer flow were studied. The stream line of erythrocytes containing paramagnetic hemoglobin showed distinct displacement toward the stronger magnetic field. The displacement increased in the order, oxygenated erythrocytes (no displacement), erythrocytes containing cyanomethemoglobin, deoxygenated erythrocytes, erythrocytes containing methemoglobin in the high spin state; more precisely the displacement was proportional to the square of the paramagnetic moment of hemoglobin contained in the erythrocytes. In addition, the displacement was proportional to the product of the magnetic flux density and its gradient, and approximately proportional to the hematocrit of the flowing-erythrocyte suspension, and was much larger than that calculated for a single erythrocyte. These phenomena could be successfully interpreted by the interaction of paramagnetic erythrocytes with the inhomogeneous magnetic field, the resistance force (Stokes Law) from the bulk water, and the hydrodynamic interaction between erythrocytes.

Blood Sedimentation↗
PubMed1987

Ventricular pressure-heart rate product before induction of ischemia as a determinant of the reperfusion-induced accumulation of calcium within myocardium.

Using the product of heart rate (HR) and left ventricular developed pressure (LVP) as a measure of the total mechanical energy required for contraction (TMEFC), experiments were performed with isolated perfused heart preparations of the guinea pig to establish the importance of TMEFC before induction of ischemia for induction of calcium accumulation within ischemic reperfused myocardium. Two calcium antagonists, diltiazem and nicardipine, and prazosin produced a dose-related suppression of the calcium accumulation when given prior to induction of ischemia (except for the highest dose of nicardipine), while they were ineffective when given only during the period of reperfusion, and the suppression was found to be closely correlated with the decrease in HRxLVP before induction of ischemia. The failure of the highest dose of nicardipine to suppress calcium accumulation (while producing a dose-related decrease in HRxLVP) was not associated with an increase in cyclic AMP. These findings are compatible with the idea that TMEFC before induction of ischemia is a prime determinant of calcium accumulation within the ischemic reperfused myocardium.

Animals↗
PubMed1987

A kinetic study on functional impairment of nitric oxide-exposed rat erythrocytes.

In acute in vivo exposure of rats to 25 to 250 ppm nitric oxide (NO) by use of a small exposure chamber for a single rat, the kinetic parameters of nitrosylhemoglobin (Hb-NO) and methemoglobin (MetHb) formation were estimated (with the aid of computer simulation) on the basis of experimental data. The biochemical and rheological injuries of erythrocytes were also examined. The time course of Hb-NO and MetHb formation in blood was compared with that simulated by a simplified kinetic model. The rate of MetHb formation from Hb-NO was much faster than MetHb reduction to ferrous form and dissociation of Hb-NO; thus, MetHb content was always greater than Hb-NO content. The activity of MetHb reduction decreased on exposure to a high concentration of NO, but the activity was recovered when rats were placed in clean air. Rheologically, the blood viscosity was scarcely altered, but a few undeformed cells were detected at high shear stress. Morphologically, echinocytic transformation was observed to some extent. Biochemically, the crosslinking of membrane proteins and the alteration of acyl chain composition of membrane phospholipids were not detected in the in vivo exposure, though the in vitro exposure of rat erythrocytes to high concentrations of NO revealed remarkable oxidative crosslinking among membrane proteins and hemoglobin. In conclusion, both for persistent methemoglobinemia and for membrane damage, the maintenance of reductive activity in erythrocytes is the most important determinant factor for the protection of NO-induced oxidative injury.

Animals↗
PubMed1987

A novel method for measuring the erythrocyte deformability, under oscillatory shear stress.

A novel apparatus for detecting a subtle decrease in erythrocyte deformability was developed. The oscillatory shape change of erythrocytes was monitored under an oscillatory shear stress (modulating the oscillation frequency in the range of 9-90 dyn/cm2). The ellipsoidal deformation of intact erythrocytes perfectly followed the oscillatory force of up to about 2 Hz, but the diamide-treated cells showed a phase difference of the oscillatory deformation at 1.7 Hz.

Erythrocyte Deformability↗