Biomedical subjects

T Kadota

Publications and source records attributed to T Kadota.

At least 73 records · Page 4Linked to original sources

PubMed1994

[Antigenicity study of paclitaxel].

The antigenic property of paclitaxel was examined using its protein mixtures (paclitaxel + OVA, paclitaxel + GSA, paclitaxel + RSA) in guinea pigs and mice in comparison with ovalbumin (OVA) and the protein conjugate of 4-aminoantipriyne (AAP). The following results were obtained: 1. When guinea pigs were sensitized with paclitaxel or paclitaxel + OVA emulsified with Freund's complete adjuvant, none of active systemic anaphylaxis (ASA), passive cutaneous anaphylaxis (PCA) and Schultz-Dale reaction were induced by challenge with paclitaxel or paclitaxel + GSA (guinea pig serum albumin). In the observation of active cutaneous anaphylaxis (ACA), no changes were observed in animals treated with paclitaxel alone as a sensitizing and/or a challenging antigen under the condition where slight delayed type hypersensitivity was elicited in animals sensitized with paclitaxel + OVA and challenged with paclitaxel + GSA. 2. When mice were sensitized with paclitaxel or paclitaxel + OVA adsorbed to alum. sera of these animals revealed a negative reaction in PCA using rats by challenge with paclitaxel or paclitaxel + RSA (rat serum albumin). 3. Protein bindings of paclitaxel with the above albumins were more than 40%. As shown above, paclitaxel was considered not to possess antigenic property under the experimental condition. In addition, the dose levels of paclitaxel employed in the present experiment were confirmed not to suppress the immune response to OVA.

Anaphylaxis↗

PubMed1994

[Irritability study of paclitaxel in rabbit ear vein].

The vascular irritability of paclitaxel at concentrations of 0.6 and 1.2 mg/ml was examined using the rabbit ear vein by a single intravenous drip in comparison with its vehicle consisting of ethanol and Cremophor, and physiological saline. The results were as follows: 1. Slight to moderate congestion was macroscopically observed around some injection sites of the retroauricular veins infused by paclitaxel, the vehicle and saline. Its incidence and severity caused by paclitaxel was not so much different from that caused by the vehicle or saline. 2. Histopathological findings at the injection sites of the rabbits treated with paclitaxel consisted of vascular and perivascular changes, as well as alterations of the dermis and epidermis. These changes were severer than those brought by saline, and dose-dependent in their incidence and severity. Moreover, the lesions caused by paclitaxel at a concentration of 1.2 mg/ml were correspondent to those caused by the vehicle. Based on these results, the microscopic examinations suggested that the vascular irritability of paclitaxel might be attributable to administration of the vehicle.

Animals↗

PubMed1994

[Toxicity studies of paclitaxel. (III)--Six-month intermittent intravenous toxicity in rats].

Paclitaxel, an antineoplastic agent, was intravenously given to Crj:CD (SD) rats of both sexes at 0 (saline), 0 (vehicle), 0.3 (low dose), 1.0 (intermediate dose) and 3.3 (high dose) mg/kg at seven-day interval over a six-month period (total of 27 doses) to investigate its repeated dose toxicity. The results obtained are summarized as follows: 1. No deaths occurred in this study. Vehicle-related salivation was seen for some high dose and vehicle control rats. Soiling of the perigenital region was observed for some high dose females. 2. Red blood cell count, hemoglobin, hematocrit and white blood cell count were decreased for high dose rats. Reticulocyte count was increased and relative neutrophil count was decreased for high dose males. 3. Relative erythroid and myeloid cell count were decreased for high dose rats in bone marrow smear examinations. 4. Bone marrow hypoplasia and splenic hemosiderosis were observed for high dose rats, and thymic atrophy and lymphoid depletion were seen for some high dose males. Based on the these results, the no-toxic effect dose of paclitaxel was estimated to be 1.0 mg/kg in rats under this study condition.

Animals↗

PubMed1994

Dynamics of presynaptic endosomes produced during transmitter release.

The movements of the presynaptic endocytotic structures produced during tetanic stimulation at 10 Hz were examined morphometrically and cytochemically in the cat superior cervical ganglion in vivo. The longitudinal profiles of the axon terminal and preterminal area were subdivided into five zones, I-V. Zone I, the area adjacent to the active zone, was assigned a hemicircle with a diameter equivalent to the active zone width (2R). Zones II-IV were defined by subdividing successively the presynaptic and preterminal areas within hemicircles with diameters equivalent to three-, five-, and sevenfold of 2R, respectively. Zone V was composed of the rest of the preterminal profile. The endocytotic structures, macropinocytotic endosomes and coated vesicles, observed in each zone were morphometrically analyzed with the time course of stimulation. The lateral surface of zone II was shown to be the main site for internalization of the terminal surface membrane during transmitter release. A large amount of the plasmalemma of zone II was rapidly retrieved by macropinocytosis to produce early endosomes at an increased rate of about three times that at rest. The population of coated vesicles, few in number at rest, increased to two- to threefold in zones II-V following the stimulation. Cytochemical examinations showed the incorporation of HRP into synaptic vesicles, endosomes and multivesicular bodies. An antibody against synaptophysin labeled the presynaptic endosomes, multivesicular bodies, coated vesicles as well as synaptic vesicles. The results have suggested that a considerable part of these endosomes was transported retrogradely at an increasing rate from zone II to zone V via zones III and IV. On the other hand, synaptophysin was observed to be distributed on the tubular protrusions of the presynaptic endosomes, suggesting the segregation and recycling of a part of synaptic vesicle proteins from the early endosomes in the nerve endings of the cat superior cervical ganglion.

Animals↗

PubMed1993

The preoptic nucleus: the probable location of the circadian pacemaker of the hagfish, Eptatretus burgeri.

By recording the locomotor activity rhythm of hagfish, Eptatretus burgeri, in which surgical lesions of the preoptic nucleus (PON) were made, we searched for the location of the circadian pacemaker in the hypothalamus. The characteristic rhythms were lost in animals lacking the anterior part of the hypothalamus, which includes the PON. Cuts in front of the PON did not affect the rhythm, but cuts behind the PON caused the animals to loose their rhythms. Destruction of the PON with a high-frequency lesion generator also caused loss of rhythms. These findings indicate that the pacemaker may be located in the PON, which has retinofugal connections.

Animals↗

PubMed1993

[Differentiation of bronchogenic carcinoma from benign nodule by MR imaging: quantitative evaluation].

To distinguish benign from malignant nodules with MR imaging, 39 pulmonary nodules (23 bronchogenic carcinomas, nine tuberculomas and seven other benign lesions) were studied. MR equipment of 1.5 Tesla was used, and relative signal intensities of pulmonary nodules on T 2- and T 1-weighted images before and after administration of gadopentate dimeglumine were evaluated. On T 2-weighted images, the relative signal intensity of bronchogenic carcinomas to subcutaneous fat was 5.48 +/- 1.69, that of tuberculomas was -2.56 +/- 2.22 and that of other benign lesions was -0.88 +/- 3.37; the difference between tuberculomas and bronchogenic carcinomas was statistically significant (p < 0.05). On T 1-weighted images before and after administration of gadopentate dimeglumine, the relative signal enhancement of bronchogenic carcinomas was 17.6 +/- 2.0, that of other benign lesions was 20.0 +/- 5.2 and that of tuberculomas was -0.0074 +/- 0.763; the difference between tuberculomas and bronchogenic carcinomas as well as benign nodules was statistically significant (p < 0.001). The relative signal intensity on T 2-weighted images and the ratio of signal enhancement to noise could differentiate tuberculomas from bronchogenic carcinomas and other benign lesions. However, bronchogenic carcinomas and other benign lesions could not be differentiated by MR imaging.

Aged↗

PubMed1993

Rapid recovery of structure and function of the cholinergic synapses in the cat superior cervical ganglion in vivo following stimulation-induced exhaustion.

Cat superior cervical ganglia (SCG) were tetanically stimulated in vivo at 30-100 Hz until neural transmission was exhausted, and then were allowed to rest and recover. Changes in their cholinergic synapses were examined electrophysiologically and morphologically during the time of tetanic stimulation and during recovery. For morphometric analysis the presynaptic terminal was subdivided into two areas: an area directly over the active zone, termed zone-I, (bounded by a hemicircle with a diameter equivalent to the active zone length), and the remaining preterminal area, termed zone-II. In control ganglia before stimulation synaptic vesicle density in zone-I (SVD-I) averaged 90 microns-2 and the number of vesicles actually attached to the active zone (SVA) averaged about 2.5 per single profile of nerve terminal. Upon stimulation, the postganglionic potential immediately began to decline in amplitude and disappeared after 1 min of stimulation. Simultaneously, SVD-I declined to less than 35 microns-2 and SVA declined to less than 1 per section. Thereafter, stimulation was terminated and the ganglion was allowed to rest. Recovery of the postganglionic potential was monitored by stimulation at 1 Hz. The postganglionic potential reached control levels after only 1 min of rest. Likewise, the structural parameters, SVD-I and SVA, also rapidly recovered, reaching control levels after only 30 sec of rest, slightly faster than the postganglionic potential. This illustrates that stimulation-induced fatigue of transmitter output and depletion of synaptic vesicles recover to the control level at a high rate in synapses of the cat SCG with a normal supply of blood. In fact, morphological recovery may be slightly faster than electrophysiological recovery. Mechanisms of vesicle formation and migration to the presynaptic area are discussed in light of these observations.

Acetylcholine↗

PubMed1993

MR imaging of oculomotor nerve neurilemmoma.

The authors present a proved case of neurilemmoma arising from the oculomotor nerve in which MR imaging, including enhancement by gadopentetate dimeglumine, dynamic study and three-dimensional gradient echo images, provided much more precise definition of the tumor.

Adult↗

PubMed1993

MR angiography of meningioma.

The clinical evaluation of three-dimensional time-of-flight MR angiography was prospectively performed in 16 patients with intracranial meningioma. MR angiographic techniques used in this study both with and without gadopentetate dimeglumine made it possible to demonstrate the topographic relationship between the tumors and the neighboring vascular structures. MR angiograms were compared with available conventional angiograms. The three-dimensional enhanced MR angiograms were successful in depicting sinus involvement in greater detail in six patients than conventional angiography. In six patients, the feeding arteries of meningiomas were demonstrated with the unenhanced MR angiograms. However, MR angiograms failed to show small feeding arteries in three patients as delineated with conventional angiography. Arterial displacement was shown in nine patients. Venous drainage and collateral circulations were also visualized in four patients. Our results indicate that multiview MR angiograms noninvasively provide useful information for planning the surgical treatment of patients with meningioma.

Cerebral Angiography↗

PubMed1993

Superoxide dismutase with prolonged in vivo half-life inhibits intravascular hemolysis and renal injury in burned rats.

Although superoxide radicals and related metabolites have been postulated to underlie the pathogenesis of burn injury, critical evidence supporting this hypothesis is lacking. To test whether superoxide radicals play critical roles in burn injury, the effect of a superoxide dismutase (SOD) derivative (SM-SOD) was tested on intravascular hemolysis and renal tubular injury in rats subjected to burn shock. Within 3 hours after a given full-thickness burn of approximately 24% of body surface area, plasma levels of lipid peroxides increased significantly with concomitant increase in intravascular hemolysis. Histological examination showed a marked deposition of hemoglobin-like casts in renal tubules of the burned rats. Intravenous administration of SM-SOD (10 mg/kg) 30 minutes before the burn injury significantly inhibited the increase of plasma lipid peroxides and the occurrence of intravascular hemolysis. SM-SOD also inhibited the deposition of casts in renal tubules. These results indicate that superoxide radicals play critical roles in the pathogenesis of intravascular hemolysis and renal damage induced by burn injury.

Animals↗

PubMed1993

Magnetic resonance imaging-histologic correlation of small hepatocellular carcinomas adenomatous hyperplasias.

RATIONALE AND OBJECTIVES: Hepatocellular carcinomas (HCCs) usually consist of components of different histologic grade. Using surgically resected specimens, the authors obtained high-resolution magnetic resonance (MR) images and studied the relationship between histologic grade of HCCs and MR signal intensity. METHOD: In vitro MRI was performed on 15 small (less than 20-mm diameter) HCCs and 2 patients with adenomatous hyperplasia (AH) within 1 hour of surgical resection. In these 17 lesions, 24 macroscopic nodular components corresponding to MR images were recognized pathologically. The difference in MR signal intensity was examined by using tumor/phantom (T/P) signal-intensity ratio. In addition, the correlations between signal intensity on MRI and histologic criteria for grading HCC were studied. RESULTS: On T2-weighted images, grade II HCCs had significantly greater T/P values than grade I HCCs (P < .01). There is the correlation (r = .88, P < .001) between nucleocytoplasmic (N/C) ratio and signal intensity of small HCCs and AHs on T2-weighted images. CONCLUSION: The N/C ratio is an important factor relating the signal intensity to the histologic grade of these lesions on T2-weighted images.

Aged↗

PubMed1993

Bladder tumors: staging with gadolinium-enhanced oblique MR imaging.

To clarify the importance of imaging plane in evaluation of invasion by tumor into muscle, 50 patients with bladder tumors underwent examination with magnetic resonance (MR) imaging performed with an oblique plane and the early phase of contrast enhancement. After the ideal oblique plane was selected, an oblique T2-weighted image was obtained. Gadopentetate dimeglumine was then administered, and an oblique T1-weighted image was obtained. The staging based on oblique T2-weighted and oblique contrast material-enhanced T1-weighted MR images was then correlated with histopathologic staging. The respective accuracies of oblique contrast-enhanced T1-weighted and oblique T2-weighted images were 78% and 60% for overall staging (P < .05), 90% and 74% for differentiation between (a) stage T1 and lower-stage tumors and (b) stage T2 and higher-stage tumors (P < .05), and 92% and 88% for differentiation between (a) stage T2 and lower-stage tumors and (b) stage T3a and higher-stage tumors (P > .05). Oblique MR imaging performed in conjunction with the early phase of contrast enhancement showed significantly high staging accuracy, especially in differentiation between superficial tumors and tumors with superficial muscle invasion.

Adult↗

PubMed1993

Bladder wall morphology: in vitro MR imaging-histopathologic correlation.

To study the morphology of the normal and inflamed bladder wall, the findings of magnetic resonance imaging and histopathologic examination of 13 in vitro specimens were correlated. Normal bladder wall appeared as a band of intermediate signal intensity on T1-weighted images and as bands of low (inner) and intermediate (outer) signal intensity on T2-weighted images. Inflamed bladder walls demonstrated two additional inner bands of intermediate (inner) and high (innermost) signal intensity on T1-weighted images and high (inner) and low (innermost) signal intensity on T2-weighted images. The mean histopathologic percentages of muscle bundles in inner and outer bands that appeared on T2-weighted images were 92.5% +/- 4.9 and 78.3% +/- 8.2, respectively. The authors conclude that the total thickness of the two bands of differing intensity that appeared on the T2-weighted images of the normal bladder wall correlated well morphometrically with the muscle layers in the histopathologic specimens, and that the different signal intensities in the muscle layer represent a compact inner and looser outer arrangement of smooth muscle bundles.

Aged↗

PubMed1993

Extradural temporal meningioma directly extended to cervical bone--case report.

A 42-year-old male presented with a rare extracranial meningioma manifesting as right facial swelling, facial nerve paresis, and hearing disturbance. Neurological imaging revealed a primarily extra-axial tumor extending from the temporal base to the subcutaneous space in the parietal region, and partially into the intra-axial region of the temporal lobe through the dura mater, with a small intracerebral hematoma and a small mass in the porus acusticus destroying the temporal bone, the floor of the middle fossa, zygomatic arch, and porus acusticus. Malignant meningioma was confirmed by histological examination after subtotal tumor removal via the transzygomatic approach. Subdural fluid accumulation like hematoma occurred 5 days after surgery and malignant cells were found in the fluid drained by skull trephination. Subsequently, radiation therapy with a total dose of 60 Gy was administered. One year later, he complained of head and neck pain with motor and sensory disturbances in the right upper extremity, and then developed tetraparesis. Cervical x-ray films demonstrated a compression fracture of the C3 vertebral bone and radiolucent areas at C2-4 levels, while computed tomography showed the tumor invading the subcutaneous space and compressing the spinal cord. He died of respiratory distress. Autopsy revealed that the tumor originated in the temporal region and had directly extended to the cervical region.

Adult↗

PubMed1993

Epidural compression of the spinal cord caused by vertebral osteoblastic metastasis of prostate carcinoma. A case report.

A 71-year-old man with prostate cancer developed epidural compression of the spinal cord caused by bony protuberances expanding from a vertebral osteoblastic metastasis. Pathologic examination of the metastatic lesion showed that both tumor and thickened vertebral trabeculae broke through the cortex and formed bony protuberances. The periosteal new bone appeared not to arise from a reactive periosteum but from the tumor breaking through the cortex. A biologic interaction between the tumor and the host may be responsible for the rare periosteal new bone formation.

Adenocarcinoma↗

PubMed1992

Localization of a 82 kDa protein in postsynaptic density and its association with cytoskeletons.

A fraction of synaptic junctional complex (SJC) was prepared from rat synaptosomes and served as antigen material to produce monoclonal antibodies (Mab) for examining the component proteins of the SJC. An antibody, Mab SJ-8, was obtained, which recognized a protein with a molecular weight of 82,000 Da in the SJC preparation by immunoblot analysis. The immunohistochemical localization of the 82 kDa protein was studied with the rat cerebellum. Mab SJ-8 labeled the peripheral areas of the Purkinje and granule cells. Small punctate areas were also stained in the molecular layer with SJ-8. Intracellular localization of the protein was examined with rat brain synaptosomes. Immunoelectron microscopy demonstrated that Mab SJ-8 strongly labeled the postsynaptic density (PSD) and also a fibrous network spreading out of it. However, the antibody did not label the pre- or post-synaptic membrane or the cleft material.

Animals↗

PubMed1992

Synaptic vesicle increase correlated to potentiation of transmission at the synapse of the cat superior cervical ganglion in vivo.

Changes in the pattern, number and size of synaptic vesicles during transmitter release were examined in the synapses of the cat superior cervical ganglion (SCG) in vivo in relation to alteration in the amplitude of postganglionic compound action potential (PGP). Stimulation of the preganglionic nerve fibers at 10 Hz caused an increase in the mean amplitude of PGP. It became augmented by approximately 30% compared to control 10-30 sec after starting the stimulation, and then gradually declined to reach a plateau after 4-6 min. This level, about 20% higher in value than control, was sustained until the end of 30 min of stimulation. The nerve terminal was divided into two areas to examine topographically the numerical changes in synaptic vesicles (SVs): zone I on the presynaptic membrane encircled with a diameter equivalent to the active zone length, and zone II occupying the remaining area outside zone I. The synaptic vesicle density in zone I (vesicle number/microns 2) was 96.9 +/- 4.8 (mean +/- S.E.M.) in the unstimulated control ganglia and 128.8 +/- 9.4 (mean +/- S.E.M.) in the ganglia stimulated for 10-30 sec, which was 30% higher in value than control. Then, it decreased slightly reaching a plateau, 20% higher in value than control. The diameter distribution of the SVs showed that their diameters in zone I (56.6 nm mean) were larger than those (51.6 nm mean) in zone II, and that prolonged stimulation induced smaller vesicles in both areas. The results showed that the increase in SV number in zone I correlated well with the elevation of PGP.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗

PubMed1992

[Cefepime (diHCl/L-arginine blend): intravenous continuous infusion and/or single dose subcutaneous toxicity study in rats and dogs].

To investigate single dose toxicity of cefepime (CFPM diHCl/L-arginine blend), the test drug was administered to rats [Crj: CD (SD)] of both sexes at dose levels of 500, 1,000 and 2,000 mg/kg using intravenous continuous infusion or subcutaneous injection, and to male beagle dogs at 1,000 and 2,000 mg/kg using intravenous continuous infusion. As the control, two additional groups of each animals were given either saline or L-arginine alone which was used in the test formulation to adjust pH values of CFPM diHCl solutions. The obtained results are summarized as follows: 1. Rats dosed with 2,000 mg/kg CFPM through intravenous continuous infusion showed slightly decreased spontaneous physical activity. One male rat dosed with L-arginine alone via continuous infusion also showed slightly decreased activity. Slight to severe inflammatory reactions at injection sites including sloughing of the tail were prominent at doses of 1,000 or 2,000 mg/kg of CFPM, or L-arginine alone. Average body weights of rats in the test groups of either sex were comparable to the controls in all of the dose groups of the same sex during the 14-day test period. 2. Rats receiving 2,000 mg/kg CFPM in single subcutaneous injection showed slightly diminished activities. Slight to moderate reactions occurred around the injection site (viz., hardening, depilation, scab-formation and necrosis) in rats injected any of the 3 doses of CFPM. Though body weight gains were slightly retarded in male rats receiving 2,000 mg/kg CFPM during the last half of the observation period, such weight gain retardation was not observed in rats of other dose groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗