Search PubMed⌕ Search

Biomedical subjects

T Harada

Publications and source records attributed to T Harada.

At least 1,387 records · Page 77Linked to original sources
PubMedDate not supplied

On the brain monoaminergic systems relating to ejaculation. III) Further study by using a peripheral decarboxylase inhibitor.

In the previous papers it was reported that ejaculation is facilitated by the brain dopaminergic system, particularly by that in the anterior hypothalamus, and inhibited by the serotonergic system. In an attempt to clarify more precisely the results, a further study was done in dogs by using a peripheral cecarboxylase inhibitor, Ro 4-4602, in combination with tetrabenazine and L-dopa. As a result it was found that in addition to the brain dopaminergic system, the increase in 5-HT level in the limbic system and the decrease in 5-HT level in the brain stem facilitate ejaculation.

Animals↗
PubMedDate not supplied

Ultrastructure of the ascospore formation of Arthroderma simii.

Ascospore formation of Arthroderma simii was observed using electron microscopy. Using scanning electron microscopy, many round asci were observed inside the gymnothecia obtained by 4 weeks of incubation after mating. Ascospores were produced inside the asci, then discoid-shaped mature ascospores were observed through the degenerate and disrupted ascus cell wall. Disseminated ascospores were observed outside the gymnothecium 7 weeks after inoculation. Using transmission electron microscopy, the enveloping membrane system of two unit membranes invaginated and delimited the cytoplasm. The inner membranes were found to have changed into ascospore plasma membranes, whereas the outer membranes and intercisternal space were changed into ascus cell wall. The subcellular events of ascospore formation were found to be essentially similar to those of other dermatophytes.

Ascomycota↗
PubMedDate not supplied

Cholinergic neuromodulation by ATP, adenosine and its N6-substituted analogues in guinea-pig ileum.

The effects of ATP, adenosine and N6-substituted adenosines, adenosine receptor agonists, on the twitch contraction of guinea-pig ileum evoked by transmural stimulation were evaluated. Adenosine and ATP produced an immediate and concentration dependent inhibition of the twitch, IC50 being 1.1 X 10(-5) mol/l and 1.2 X 10(-5) mol/l, respectively. N6-l-phenylisopropyl adenosine (L-PIA), N6-cyclohexyl adenosine (CHA) and N6-allyl adenosine also induced inhibitions which were gradual and persistent, IC50 being 2.6 X 10(-8), 2.7 X 10(-8) and 5.4 X 10(-7) mol/l, respectively. Dipyridamole (10(-7) mol/l), an adenosine uptake inhibitor, markedly augmented the inhibition evoked by adenosine and ATP, but not that by three N6-substituted adenosines, while theophylline (10(-4) mol/l) almost completely antagonized the inhibitory effects of all purine compounds. IC50 value of adenosine in the presence of dipyridamole (5 X 10(-7) mol/l) was shifted to the left about 50 times from the control, whereas that of L-PIA was virtually unchanged. Tissue-medium ratios indicating uptake of [3H]adenosine, [3H]ATP and [3H]CHA into the segment were 3.23 (s.e.m. = 0.59), 3.59 (s.e.m. = 0.78) and 0.41 (s.e.m. = 0.04), respectively. These results suggest that not only adenosine and ATP but also these N6-substituted adenosines are potent agonists for the P1 receptor, implying a similarity between P1 and A1 receptor in a functional role and these purine compounds may thereby modulate cholinergic neurotransmission by altering adenylate cyclase activity.

Adenosine↗
PubMedDate not supplied

Mechanisms of photoinduced cochlear ischemia in the guinea pig.

An experimental model of cochlear ischemia using the photosensitization reaction of rose bengal (RB) is reported. Ischemia was induced by the systemic administration of RB solution and localized irradiation of the cochlea with a green light of specific wavelength for RB activation. After the RB solution was administered, the cochlear blood flow was temporarily increased and then decreased, and the latency of wave I of the auditory brainstem response increased and the amplitude of wave I decreased after RB injection and finally wave I disappeared completely. A histological study revealed thrombus formation in the vessels of the irradiated cochlea not only in the stria vascularis and the spiral ligament, but also in the modiolus. L-Histidine, a scavenger of singlet oxygen (1O2) and hydroxyl radical (.OH), significantly prolonged cochlear dysfunction, but D-mannitol, a specific scavenger of.OH did not, suggesting that 1O2 has an important role in this reaction.

Animals↗
PubMedDate not supplied

Congenital cholesteatoma of the petrous pyramid.

A congenital cholesteatoma arising from the petrous pyramid is rarely encountered, and we report a case of such a cholesteatoma in a 23-year-old male. This cholesteatoma was successfully removed by a middle cranial fossa approach. The cholesteatoma showed a unique mode of spread, that is, it originated from the pyramidal apex and extended in two directions: through the facial canal to the tympanic sinus, and along the tympanic tegmen to the mastoid antrum. We discuss the importance of CT and MRI for achieving a diagnosis, as well as the merits of using a middle cranial fossa approach for the surgical excision of this cholesteatoma.

Adult↗
PubMedDate not supplied

Sudden deafness: histopathologic correlation in temporal bone.

The histopathological study of two cases of sudden deafness is presented. The temporal bones showed cochleosaccular abnormality. The most striking pathological changes were collapse of the organ of Corti, atrophy of the tectorial membrane, atrophy of the stria vascularis, decrease in the number of the cochlear nerves, collapse of the saccular membrane and partial absence of the sensory epithelial layer in the saccular macula. These changes are quite similar in type to those occurring in labyrinthitis of known viral etiology and to those in previously reported cases of sudden deafness which were assumed to be of viral origin. This evidence suggests that a viral infection was the most probable etiology of sudden deafness in these ears. In addition, unusual findings of endolymphatic hydrops limited to the extreme basal end of the cochlear duct were found in Case 1. A patent cochlear aqueduct and circumscribed perilymphatic labyrinthine ossification in the superior seimicircular canal were also observed. With these histopathological findings, the possibility of viral infection via the meninges as well as via the hematogenous route into the inner ear is proposed.

Cochlea↗
PubMedDate not supplied

Temporal bone histopathology in deafness due to cryptococcal meningitis.

This paper reports on a patient who survived an attack of cryptococcal meningitis eight years prior to his death. A bilateral sensorineural hearing loss had been noted a short time before the patient was admitted to the hospital, and was the only complication after he recovered from the disease. Histopathologic study of the temporal bones showed a similar pattern of pathology in both ears, the most striking finding being a severe loss of spiral ganglion cells in Rosenthal's canal, and of cochlear nerve fibers in the osseous spiral lamina and internal auditory meatus. The vestibular nerve was mostly free from pathology. The organ of Corti was atrophic but the hair cell population appeared to be almost normal. A slight number of cryptococci were observed in limited areas of the cochlear and the saccular nerves in the internal auditory meatus. The severe pathology of the cochlear nerve was compatible with audiologic evaluations, which pointed to a retrocochlear lesion. Thus, this case demonstrates some characteristic aspects of cryptococcal infection of the temporal bone: The primary site of invasion was the cochlear nerve in the internal auditory meatus and the modiolus, leading to the loss of ganglion cells and nerve fibers, while the vestibular nerve appears to have been resistant to infection.

Cochlear Nerve↗
PubMedDate not supplied

Course and contents of the paravestibular canaliculus.

The purpose of this study is to describe the anatomy of the paravestibular canaliculus (PVC) in detail, especially its course in relation to the vestibular aqueduct (VA) and its vascular contents. Serial horizontal sections of 20 normal human temporal bones were stained either with hematoxylin and eosin, by Verhoeff-van Gieson's method, or by Mallorys method, and studied under the light microscope. Graphic reconstruction of the VA and the PVC was performed in some of the cases. In this study, the following new anatomical information on the common course and vascular contents of the PVC was obtained: 1) two PVC are present in the area near the vestibular orifice of the VA; 2) the PVC merges with the VA in the area near its cranial orifice without any particular branching, and does not enter the posterior cranial fosa; 3) veins course through the entire length of the PVC whereas arteries course only through the posterior cranial fossa side of the PVC. It appears that veins are the major contents of the PVC and that these veins represent the main venous drainage system from the vestibule. It also appears that arteries in the PVC supply the blood from the posterior cranial fossa mainly to the PVC itself.

Arteries↗
PubMedDate not supplied

Temporal bone histopathology of necrotizing external otitis. A case report.

Histopathological examination of the temporal bone of an individual with necrotizing external otitis revealed severe inflammation with necrosis in the subcutaneous granulation tissue in the external auditory canal. Erosion of the bony walls of the canal had created a defect in the anterior wall, through which infection spread to the preauricular region. The lateral part of the middle ear cavity was also filled with granulation tissue and purulent exudate. A dehiscence of the horizontal portion of the facial canal had apparently allowed spread of an inflammatory round cell infiltrate along the facial nerve up to the fundus of the internal auditory canal. The only evidence of inner ear pathology was the presence of eosinophilic fluid material in the perilymphatic spaces of the labyrinth. A review of other reports of cases of necrotizing external otitis seems to show that this is the only instance of this disease in which infection spread from the external canal through the tympanic membrane to the middle ear and thence to the internal auditory canal.

Aged↗
PubMedDate not supplied

Microfissure in the oval window area.

Examination of 331 human temporal bones revealed the presence of microfissure in the oval window area in 25%. The youngest temporal bone in which the microfissure was observed was from a child eight years old and the oldest temporal bone was from an individual 102 years old. It appears that hte microfissure in this area occurs extremely rarely before 10 years of age, that it begins to be observed after the age of 10, and that the incidence of this fissure increases sharply at about age 40. In 61% of the bones in which the microfissure was observed, it was present both superior and inferior to the oval window in almost the same vertical plane. In none of the bones, however, did it extend beyond the annular ligament to the footplate. The histological appearance of the microfissure in this area was quite similar to that of the microfissure between the posterior canal ampulla and round window niche, although the latter appeared to be wider in general. The histogenesis of the microfissure is still unknown, but upon careful analysis of the results of this study and literature review, the authors consider nontraumatic spontaneous fracture by mechanical stress to be the most probable explanation for its occurrence. Possible clinical significance of the microfissure is also discussed.

Adolescent↗
PubMedDate not supplied

Ototoxicity of neomycin and its penetration through the round window membrane into the perilymph.

The ototoxicity of neomycin and its concentration in the perilymph after direct application on the round window membrane were studied. After placing 5 mg of neomycin on the round window membrane of guinea pigs for various time intervals, concentration of the drug in the perilymph was determined by high performance liquid chromatography, and the cochlea was examined by light microscopy. Neomycin penetrated the round window membrane quite easily, and its concentration in the perilymph became extremely high in a short time and then decreased gradually. This indicates that high concentration of neomycin in the perilymph can be attained by application of a small amount of the drug on the round window membrane. Ototoxicity of neomycin was observed after application for 4 hours. Cochlear damage increased as neomycin application time became longer, but no consistent relationship was noted between the concentration of neomycin and the amount of damage. This result is discussed from the point of concentration and persistence of the drug in the inner ear fluids.

Animals↗
PubMedDate not supplied

Immunologic responses against lipopolysaccharide of Hemophilus influenzae in patients with acute sinusitis.

The serum antibodies against lipopolysaccharide of Hemophilus influenzae were measured in acute and convalescent phase sera from 30 patients with acute maxillary sinusitis using enzyme-linked immunosorbent assay. Levels of antibodies in the maxillary antral secretions were also measured. In convalescent phase sera from 15 patients with acute sinusitis due to H influenzae, there was a threefold, 1.5-fold, and threefold increase in the geometric mean titers of IgG, IgM, and IgA, respectively. In antral secretions, titers were significantly higher (p less than .01) in culture-positive patients than in culture-negative patients for all antibodies. These data indicate that the immune system has the ability to respond systemically and locally with specific antibodies against lipopolysaccharide of H influenzae.

Acute Disease↗
PubMedDate not supplied

Serum levels of vitamin D metabolites in children receiving total parenteral nutrition.

Serum levels of 25-hydroxyvitamin D (25-OHD) and 1,25-dihydroxyvitamin D (1,25-(OH)2D) were measured on 19 occasions in seven children receiving total parenteral nutrition (TPN). The daily intakes of vitamin D3 ranged from 44 to 540 IU/day, and all serum samples were obtained after the same daily intake of vitamin D3 for more than 1 month. There was a significant positive correlation between serum 25-OHD levels and parenteral vitamin D3 intakes (r = 0.90, p less than 0.01). In this study, serum 25-OHD levels in all cases taking 200 to 360 IU/day of vitamin D3 were within the normal range. On the other hand, no significant correlation was found between serum 1,25-(OH)2D levels and vitamin D3 intakes, and serum 1,25-(OH)2D levels were normal or elevated in all cases.

Calcifediol↗
PubMedDate not supplied

Effects of alternate and simultaneous administrations of calcium and phosphorus on calcium metabolism in children receiving total parenteral nutrition.

The effects of alternate and simultaneous administrations of calcium (Ca) and phosphorus (P) on Ca metabolism in children receiving total parenteral nutrition (TPN) were examined. Eight children, aged 2 to 36 months, were studied. The following three solutions were administered: solution 1 contains Ca (533 mg/liter); solution 2 contains P (413 mg/liter); and solution 3 contains Ca (267 mg/liter) and P (207 mg/liter). Solutions 1 and 2 were administered alternately for 24-hr periods. (Results) I. During administration of solution 1, significant hypophosphatemia (4.39 +/- 0.26 mg/dl) and hypercalcemia (9.96 +/- 0.15 mg/dl) were observed and, conversely, during administration of solution 2, significant hypocalcemia (8.36 +/- 0.18 mg/dl) and hyperphosphatemia (6.16 +/- 0.27 mg/dl) were observed. During administration of solution 3, the serum levels of both minerals were maintained within the normal ranges (Ca 9.46 +/- 0.12 mg/dl, P 5.65 +/- 0.21 mg/dl). II. The urinary excretion of cyclic AMP was significantly lower during administration of solution 1 (6.67 +/- 0.45 nmol/mg creatinine (Cr] as compared with solution 3 (7.50 +/- 0.61 nmol/mg of Cr). On the other hand, the excretion was significantly higher during administration of solution 2 (11.55 +/- 1.58 nmol/mg of Cr) as compared with solution 3, indicating the existence of secondary hyperparathyroidism. III. The Ca and P retention rates were significantly higher with solution 3 (Ca 79.0 +/- 5.5%, P 73.2 +/- 7.2% of the intake) than with solutions 1 and 2 alternately (Ca 62.7 +/- 4.5%, P 49.2 +/- 9.3%). (Conclusions) Simultaneous administrations of Ca and P are preferable to their alternate administrations for Ca metabolism in children receiving TPN.

Bone and Bones↗
PubMedDate not supplied

Manganese deposition in the brain during long-term total parenteral nutrition.

BACKGROUND: Manganese deposition was suspected in a pediatric patient who received long-term total parenteral nutrition. T1-weighted magnetic resonance images revealed high intensity areas in the globus pallidus. This study was designed to clarify if these abnormal findings were related to manganese deposition and clinical neurological manifestations. METHODS: Whole-blood manganese concentrations were measured during manganese supplementation to total parenteral nutrition and after 5 months without manganese. Magnetic resonance images were also examined on each occasion and compared with the blood level of manganese. RESULTS: The whole-blood manganese level during supplementation was 135 micrograms/L (normal range 14.6 +/- 4.7 micrograms/L), whereas the level was 20 micrograms/L after a manganese-free period of 5 months. Accompanied with normalization of manganese level, abnormal high intensity lesions in the globus pallidus on T1-weighted images also disappeared. No neurological manifestation related to the high manganese level was recognized. CONCLUSIONS: It is probable that the high manganese level was elicited by manganese supplementation to total parenteral nutrition. This high manganese condition was confirmed by the measurement of whole-blood manganese level, which was associated with the abnormal high intensity lesions on T1-weighted magnetic resonance images.

Brain↗
PubMedDate not supplied

Long-term outcome of short bowel syndrome in adult and pediatric patients.

We reviewed 12 pediatric and 18 adult patients with short bowel syndrome (SBS) from Osaka University Hospital and compared clinical characteristics between them. The length of the residual small intestine ranged from 0 to 75 cm (mean 47 cm) in pediatric patients and from 0 to 150 cm (mean 47 cm) in adult patients. In all cases, total parenteral nutrition (TPN) was started immediately after surgery and was gradually replaced by enteral nutrition. Eight pediatric patients (67%) and 4 adult patients (22%) were weaned from TPN. Residual intestinal length in these patients ranged from 27 to 75 cm (mean 57 cm) in pediatric patients and 57 to 150 cm (mean 96 cm) in adult patients. Pediatric patients with residual small intestinal lengths of 0, 16, 25, and 45 cm were not weaned from TPN. None of the adult patients with residual small intestinal length less than 40 cm could achieve complete intestinal adaptation. Five adult patients died due to liver failure (2 cases), heart failure (2 cases), or pneumonia (1 case), whereas all pediatric patients survived. The average life span of indwelling central venous catheters was 511 days and 780 days, and the rate of catheter-related sepsis per 1000 catheter days was 0.73 and 0.48 in pediatric and adult patients, respectively. Plasma levels of arginine and citrulline in patients receiving TPN were significantly decreased compared with those in patients receiving TPN without SBS both in pediatric and adult patients (p < .01). These results indicate that pediatric and adult patients with SBS can survive with TPN and enteral nutrition. The minimum remaining intestinal length necessary for complete bowel adaptation is shorter for pediatric patients than adults, suggesting better bowel adaptation in pediatric patients.

Adaptation, Physiological↗
PubMedDate not supplied

Spontaneous adrenal and hepatic myelolipomas in the common marmoset.

Myelolipomas occurring simultaneously in the adrenal and liver were found in a 2.7-yr-old, bred female common marmoset (Callithrix jacchus). The animal bore single adrenal and multiple hepatic myelolipomas. The adrenal myelolipoma consisted of mature adipose cells and focal collections of normal hematopoietic elements and was unencapsulated. In the liver, the myelolipomas, which were partially encapsulated, included a large amount of hematopoietic tissue and adipose cells that resembled normal bone marrow cells in various ways. Additionally, one of the multiple nodules contained several bony spicules with osteoblasts. Furthermore, there were invasive figures of hematopoietic cells, such as myeloblasts, erythroblasts, and megakaryocytes, in the hepatic sinusoids around the lesions. Thus, this case has some unusual morphological characteristics and is the first report, to our knowledge, on multiorganic myelolipomas in common marmosets.

Adrenal Gland Neoplasms↗