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Biomedical subjects

M Kudo

Publications and source records attributed to M Kudo.

At least 325 records · Page 18Linked to original sources
PubMed1990

In vivo estimates of hepatic binding protein concentration: correlation with classical indicators of hepatic functional reserve.

Hepatic binding protein (HBP) is a hepatic cell surface receptor specific for asialoglycoprotein. In vivo estimates of HBP concentration ([HBP]) were compared to classical indicators for hepatic functional reserve to clarify the validity of [HBP] in estimating the hepatic functional reserve in 30 humans. Estimates of [HBP] were obtained based on kinetic analysis of liver and blood time-activity data resulting from the hepatic clearance of a single injection of technetium-99m galactosyl-neoglycoalbumin, which is a synthetic analog radioligand specific to HBP. Estimates of [HBP] ranged 0.054 to 0.720 microM. Estimates of [HBP] in normal volunteers were 0.668 +/- 0.050 microM, whereas that in liver cirrhosis were 0.188 +/- 0.112 microM. The difference between the mean values of [HBP] estimates was statistically significant (p = 0.0001). Good correlations were observed between [HBP] and prothrombin time (r = 0.625, p = 0.0002), serum albumin level (r = 0.687, p = 0.0001), serum cholinesterase level (r = 0.764, p = 0.0001), indocyanine green plasma disappearance rate (r = 0.602, p = 0.0024), and Child-Turcotte classification score (Pugh's modification) (r = -0.797, p = 0.0001). We concluded that excellent correlations of [HBP] with classical indicators for hepatic functional reserve suggest potential value of [HBP] as a sensitive measure of functioning hepatocyte mass.

Adult↗
PubMed1990

[Malignant schwannoma of acoustic nerve: a case report].

During a routine physical examination in 1976, a 54-year-old man was noted to suffer from hearing difficulty and continuing tinnitus of his right ear. He had, however, no further consultations for the next five years, although the symptom persisted and gradually worsened. In May 1981, he experienced complete hearing loss in his right ear. A computed tomography disclosed no abnormalities, and other laboratory tests were unremarkable. In September 1981, the patient began to complain of paresthesia of the right angle of the mouth and tongue, right-sided facial paralysis, and walking difficulty. A repeated computed tomography showed a tumor at the right cerebellopontine angle region. A clinical diagnosis of acoustic schwannoma was made. The first operation was performed in December 1981. Complete removal of the tumor was impossible because of its unexpected, unusual hardness. The pathologic diagnosis was a malignant mesenchymal tumor, compatible with a malignant nerve sheath tumor of the acoustic nerve. A second operation was performed in January 1982, but the rapid postoperative regrowth of the tumor necessitated a third operation in March 1982. The patient died in the next month. Family histories did not show any evidence of von Recklinghausen's disease, and neither did the patient have any clinical stigmata of this disease.

Cerebellopontine Angle↗
PubMed1989

Monosynaptic nigral inputs to the pedunculopontine tegmental nucleus neurons which send their axons to the medial reticular formation in the medulla oblongata. An electron microscopic study in the cat.

An electron microscopic study in the cat has suggested that neurons in the substantia nigra pars reticulata (SNr) project to the medial reticular formation of the medulla oblongata (MRF) via the pedunculopontine tegmental nucleus (PPN): PPN neurons, which were labeled with a retrograde tracer (WGA-HRP; horseradish peroxidase conjugated to wheat germ agglutinin) injected into the MRF, were found to be in synaptic contact with axon terminals which were degenerated with neurotoxic agents applied into the SNr.

Animals↗
PubMed1989

Monosynaptic striatal inputs to the nigrotegmental neurons: an electron microscopic study in the cat.

The cat substantia nigra (SN) pars reticulata (SNR) has been observed electron microscopically after ibotenic acid injections into the caudate nucleus (Cd) and horseradish peroxidase injections into the nucleus tegmenti pedunculopontinus pars compacta (TPC). As a result, degenerating striatal terminals were found to make symmetric synaptic contacts on retrogradely labeled SNR neurons. The present findings, together with our previous study on the tegmentonigrostriatal projection (Tokuno et al., Neurosci. Lett. 85 (1988) 1-4), confirm that the Cd has indirect reciprocal connections with the TPC via the SN.

Animals↗
PubMed1989

The cerebral and cerebellar connections of pretecto-thalamic and pretecto-olivary neurons in the anterior pretectal nucleus of the cat.

The neuronal connections of the anterior pretectal nucleus (PTA) were investigated in the cat. For the light microscopy, the retrograde double-labeling technique by means of Fluoro-Gold (FG) and horseradish peroxidase conjugated to wheat germ agglutinin (WGA-HRP) was used. Following injections of one tracer into the central lateral nucleus of the thalamus (CL) and the other into the dorsal accessory olivary nucleus (DAO), distributions of labeled neurons in the PTA were observed. Most of the labeled neurons were single-labeled either with FG or with WGA-HRP. The result indicated that pretecto-thalamic projection neurons were distributed throughout the whole extent of the PTA, whereas pretecto-olivary projection neurons were located in a restricted area of the ventral part of the PTA. Only a very small number of double-labeled neurons were found in the PTA. These two efferent projections thus seemed to be derived from different populations of PTA neurons. For the electron microscopy, a combination of retrograde transport of horseradish peroxidase (HRP) and anterograde degeneration technique was used. After HRP injections into the CL combined with lesions either in the motor cortex (MCx) or in the anterior interpositus nucleus of the cerebellum (Cbl), some degenerating axon terminals originating from the cerebrum or cerebellum were found to synapse with retrogradely labeled pretecto-thalamic projection neurons. We have already observed direct cerebral and cerebellar projections to the pretecto-olivary projection neurons (J. Comp. Neurol., 259 (1987) 348-363). We conclude that the two different populations of PTA neurons comprise two different kinds of neuronal circuitries, i.e. MCx-PTA-CL-MCx and Cbl-PTA-DAO-Cbl, and that these two circuitries might interrelate with each other in the PTA at the cellular level.

Animals↗
PubMed1989

Synaptic organization of the pedunculopontine tegmental nucleus of the cat.

The synaptic organization of the feline pedunculopontine tegmental nucleus (PPN) was studied electron microscopically. The bouton covering ratios were calculated in various sizes of PPN neurons, and the ratios of large neurons (56%) were found to be much higher than those of small neurons (16%). The PPN neuron dendrites usually showed some varicosities, and spines were observed on both somatic and dendritic profiles. Among a total of 1021 synapses sampled at random, axosomatic, axodendritic and axospinous synapses comprised 21.7, 61.2 and 14.1%, respectively. On the basis of the postsynaptic junction, these synapses were classified into the symmetric (66.3%) and the asymmetric (33.7%) types. The percentage of symmetric synapses was much higher on the soma (91.0%), and the large (69.4%) and medium-sized (63.2%) dendrite, while that of asymmetric synapses showed a higher value on the small dendrite (55.5%) and the dendritic spine (50.8%). Axoaxonic, dendrodendritic and dendroaxonic synapses, although not so frequent, were, in part, involved in the serial synapse or the synaptic triad. It is concluded that some PPN neurons are spiny, and that axosomatic, axodendritic and axospinous synapses are the main synaptic constituents and besides those synapses a more complex synaptic organization exists in this nucleus.

Animals↗
PubMed1989

Auditory forebrain organization of an Australian marsupial, the northern native cat (Dasyurus hallucatus).

Structures and connections of auditory forebrain regions of the Northern native cat, a member of one of the most primitive families among Australian marsupials, have been examined anatomically by using anterograde and retrograde tracing techniques with wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) after defining the acoustically responsive neocortical area physiologically. The structure of the medial geniculate body (MG) was similar to that described in other species. The results obtained from a case with a WGA-HRP injection into the MG showed that the MG strongly projects to the lateral amygdaloid nucleus (LAmy) and the putamen as well as the auditory neocortex (ACx). Results obtained from other cases with WGA-HRP injections into the physiologically defined ACx show also that the ACx is connected not only with the ipsilateral MG and the contralateral ACx but also with the LAmy both bilaterally and reciprocally. The regions within the LAmy in which the MG-LAmy projection fibers terminate largely overlap with those in which the ACx-LAmy fibers terminate and the LAmy-ACx pathway originates. The connectional relationships revealed in the present study--that the LAmy receives auditory information from the MG and reciprocates auditory information with the ACx bilaterally--strongly suggest that, in some primitive mammals with small neocortical areas, a specific portion of noncortical telencephalon functions as an auditory center and occupies a relatively large volume of space in the forebrain. It is possible that the auditory sector of noncortical telencephalon in some primitive mammals such as the American Didelphidae and the Australian Dasyuridae is homologous with part of the auditory sector of the dorsal ventricular ridge (DVR) in reptiles and birds and also may have functions shared with the auditory primary and association neocortex in advanced mammals such as the domestic cat and the monkey (Kudo et al., '86a).

Animals↗
PubMed1989

The sites of intra-embryonic haemopoiesis prior to the hepatic haemopoiesis in the chick.

The sites of intra-embryonic haemopoiesis of the chick embryo (stages 15-26) preceding the initiation of hepatic haemopoiesis was investigated by means of serial sections stained with azan liquid. Hitherto undescribed blood islands of large size and clear outline were found in the neck and lateral body fold of the embryo. They consisted of dense aggregations of erythroblasts and thin endothelial cells surrounding them, and could be clearly identified by azan staining. In the neck, the blood islands were located near the branchyal arteries at stages 15-18, while in the lateral fold they were seen mainly at stages 17-19. Examination of serial sections indicated that the blood islands extended in a cephalocaudal direction, assuming a rod shape. The largest blood island was found in the lateral fold, measuring 50 microns in diameter and 900 microns in length. Besides these islands, occasional sites of haemopoiesis were found in the mesonephros, mesentery, dorsal regions of the trunk, head and allantois after stage 18. As the blood islands found in this study alternated their localization sites according to developmental stage, they were considered to be temporary haemopoietic tissues rather than persistent ones.

Animals↗
PubMed1989

Distinction between hemangioma of the liver and hepatocellular carcinoma: value of labeled RBC-SPECT scanning.

The role of adding single-photon emission CT (SPECT) to 99mTc-labeled RBC imaging of the liver was evaluated by specifically focusing on the differentiation between hepatic hemangioma and hepatocellular carcinoma. Planar RBC imaging followed by blood-pool SPECT scanning was performed in 77 patients with a total of 108 hemangiomas and in 29 patients with a total of 46 hepatocellular carcinomas. All lesions were smaller than 5 cm in diameter. Thirty-six (33%) of 108 hemangiomas were detected by planar delayed RBC imaging, whereas 63 (58%) were detected by the delayed RBC-SPECT scan. The smallest hemangioma shown by delayed RBC-SPECT scanning was 1.4 cm in diameter, compared with 1.7 cm by planar RBC scanning. When confined to nodules larger than 1.4 cm in diameter, 42% of hemangiomas (36/85) were detected by planar delayed RBC imaging, whereas 74% (63/85) were detected by delayed RBC-SPECT. Increase in sensitivity was noted in nodules 2.1-4.0 cm in diameter. No hepatocellular carcinomas were shown by delayed RBC planar or SPECT scans. We concluded that with the addition of SPECT, the sensitivity of delayed RBC scans in the detection of small hemangiomas is considerably improved. Delayed RBC-SPECT scanning can be used to distinguish hemangioma from hepatocellular carcinoma.

Adult↗
PubMed1989

[Effects of surgical intervention on plasma levels of antidiuretic hormone and alpha-human atrial natriuretic polypeptide under sevoflurane anesthesia].

Effects of surgical intervention on plasma levels of antidiuretic hormone (ADH) and alpha-human atrial natriuretic polypeptide (alpha-hANP) under sevoflurane-nitrous oxide-oxygen anesthesia were evaluated in 24 patients, ranged in ages from 15 to 65, who underwent non-abdominal surgery (orthopedic surgery) or abdominal surgery (gastrointestinal or gynecological surgery). Anesthesia was induced and maintained with sevoflurane, nitrous oxide and oxygen. Succinylcholine was administered to facilitate tracheal intubation and pancuronium was given during abdominal surgery when needed. Lactated Ringer's solution was administered intravenously throughout the procedures. Neither plasma ADH nor alpha-hANP levels changed significantly during sevoflurane anesthesia alone for 20 min. Plasma ADH levels were unchanged during surgery in patients who underwent non-abdominal surgery, but they tended to increase although insignificantly after the recovery from anesthesia. On the contrary, plasma ADH levels increased significantly during surgery and in the recovery room in patients who underwent abdominal surgery. Plasma alpha-hANP levels were unchanged during surgery and in the recovery room in patients who underwent non-abdominal or abdominal surgery. The authors' findings suggest that ADH secretion was significantly stimulated with abdominal intervention but not with orthopedic one, furthermore neither anesthesia nor surgical stress induced any influence on plasma alpha-hANP levels.

Adolescent↗
PubMed1989

[Effects of intravenous anesthetics and analgesics on plasma alpha-rat atrial natriuretic peptide (alpha-rANP) levels in rats].

Effects of various intravenous anesthetics and analgesics on alpha-rat atrial natriuretic peptide (alpha-rANP) concentrations in the plasma were studied in unrestrained rats. Morphine (30 mg.kg-1), fentanyl (0.2mg.kg-1) and buprenorphine (1mg.kg-1) produced 10-, 10- and 3.3-fold significant increases in plasma alpha-rANP over control group at 20min after intraperitoneal injections of each drug, respectively. A marked increase in plasma alpha-rANP after morphine administration was still observed at 60min, but those after fentanyl and buprenorphine were reduced to 4.7-from 10.0-fold and 1.6-from 3.3-fold increase at 60min, respectively. Pentazocine (40mg.kg-1) significantly increased plasma alpha-rANP to 1.3 times higher than that of control group only at 60 min, while ketamine (40mg.kg-1) caused an insignificant increase in plasma alpha-rANP to 1.4 and 1.3 times at 40 and 60 min. Droperidol (10mg.kg-1) tended to decrease plasma alpha-rANP and a significant reduction was observed at 60 min. Propofol (40mg.kg-1) did not affect on plasma alpha-rANP. Pentobarbital (50mg.kg-1) produced an insignificant fall in plasma alpha-rANP. Plasma levels of ACTH, compB and aldosterone increased after injections of morphine and fentanyl. These results indicate that mu-type opiate receptor plays an important role in secreting alpha-rANP and activating pituitary-adrenal axis in the rats.

Analgesics↗
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

[Effect of dexamethasone and ACTH on plasma atrial natriuretic polypeptide levels during hemorrhage in rats].

Anti-shock effect of dexamethasone (Dexa) and ACTH on atrial natriuretic polypeptide (ir-ANP) secretion was studied during hemorrhage in rats as reflected in the plasma ir-ANP, corticosterone (Comp B) and ACTH levels. We also observed the number of survived rats and plasma ir-ANP levels stimulated by volume loading of the shed blood or fluid. The rats were divided into non-treated group (saline), Dexa group (Dexa 5mg.kg-1) and ACTH group (ACTH 200 micrograms.kg-1). They were anesthetized by intravenous injection of pentobarbital sodium 30 mg.kg-1. Atrial blood sample for control value was collected before hemorrhage. Approximately 20% and then 30% of the estimated blood volume was taken for hemorrhage. Hemorrhage induced significant reductions in plasma ir-ANP levels. They decreased from a control value of 133.8 +/- 6.1 pg.ml-1 to 76.6 +/- 4.2 pg.ml-1 (P less than 0.005), but plasma levels of Comp B and ACTH increased markedly. The ir-ANP secretion increased in response to the elevation of atrial pressures after volume loading. The administration of Dexa and ACTH to the rats tended to inhibit the reduction of plasma ir-ANP levels during hemorrhage and improved the survival rate 24hr after bleeding 30% of the estimated blood volume.

Adrenocorticotropic Hormone↗
PubMed1989

Neuroectodermal differentiation in "extraskeletal Ewing's sarcoma".

A small round cell tumor of soft tissue arising in the retroperitoneum of an 18-year-old woman is reported. The light and electron microscopic features of the tumor were mostly indistinguishable from Ewing's sarcoma of the bone and in some parts from differentiating neuroblastoma with mature neurons and Schwann cells. An immunohistochemical study using anti-NSE antibody showed many widespread NSE-positive cells lying singly and, more often, in clusters including the undifferentiated areas. The tumor was not anatomically related to the paravertebral sympathetic ganglia or adrenal glands. The present findings strongly suggest that certain extraskeletal Ewing's sarcomas are very primitive neuroectodermal tumors.

Adolescent↗
PubMed1989

[Effects of sevoflurane anesthesia and surgery on plasma catecholamine levels].

Effects of sevoflurane-nitrous oxide-oxygen anesthesia and surgery on plasma levels of epinephrine, norepinephrine and dopamine were evaluated in twenty four patients who ranged in ages from 15 to 65 years. They underwent non-abdominal surgery (orthopedic surgery) or abdominal surgery (gastrointestinal or gynecological surgery). Anesthesia was induced and maintained with sevoflurane in 50% nitrous oxide and 50% oxygen. Succinylcholine was administered intravenously to facilitate tracheal intubation and pancuronium was given intravenously during surgery. Lactated Ringer's solution at a speed of 5-15 ml.kg-1.h-1 was also administered intravenously throughout the procedures. Neither plasma epinephrine, norepinephrine nor dopamine levels changed significantly during the anesthetic induction with sevoflurane anesthesia. Plasma catecholamines were unchanged during and after surgery in patients who underwent non-abdominal surgery, while plasma epinephrine and norepinephrine levels increased significantly during and after abdominal surgery. Plasma dopamine levels, however, were unchanged during and after surgery in these patients. The findings suggest that epinephrine and norepinephrine secretion was significantly stimulated with abdominal intervention but not with orthopedic one under sevoflurane anesthesia.

Adolescent↗