Biomedical subjects

N Otsuka

Publications and source records attributed to N Otsuka.

At least 37 records · Page 2Linked to original sources

PubMed1998

Unmyelinated nerve fiber analysis of the human abducent nerve.

Unmyelinated nerve fibers of the abducent nerve have occasionally been observed with electron microscopes, but, to our knowledge, they have never been evaluated from the morphometric point of view. We analyzed the aging process of the unmyelinated nerve fibers in the human abducent nerve with the help of a new staining method suitable for morphometric research on the nervous system. We studied numbers and transverse areas of unmyelinated fibers of the abducent nerve in 10 cadavers. Our findings were that (1) these fibers were distributed diffusely, (2) their number decreased with age, and (3) the mean transverse area did not change with age. Most of the unmyelinated axons were thinner than the myelinated axons. These results may be important for analysis of clinical signs in relation to aging and ophthalmologic functions.

Abducens Nerve↗

PubMed1998

Morphometric nerve fiber analysis and aging process of the human abducent nerve.

Myelinated nerve fibers of the human abducent nerve were analyzed with a new staining method that permits simultaneous observation of the axon and surrounding myelin sheath. The following equipment was employed for the measurements: an image-analyzing digitizer, a microscope equipped with a drawing tube (or camera lucida), and a computer for data storage and statistical analysis. The numbers, transverse areas, and circularity ratios of axons were measured in 10 human abducent nerves. The average number was 1,997 with a definite decrease with age, and the average area was 3.90 micron 2.

Abducens Nerve↗

PubMed1997

Ultrastructural localization of CD38 immunoreactivity in rat brain.

The subcellular localization of CD38 in the rat cerebral and cerebellar cortices was studied using immunoelectron microscopy. In the cerebral cortex, immunoreactivity was present in a subset of pyramidal neurons, and was distributed predominantly in the perikarya and dendrites. It was found in association with rough endoplasmic reticulum, ribosomes, small vesicles, mitochondria and the plasma membrane including the postsynaptic densities. In the cerebellum, labeling was observed in several types of neuron such as granule, Golgi, basket and Purkinje cells. In contrast to the cerebrum, immunoreactivity was accentuated in the perikarya or axon terminals, and the synaptic vesicles represented another organelle that was immunopositive for CD38. In both of these CNS regions, the nuclear envelope, particularly the outer membrane, showed constant labeling. Diffuse immunoreactivity was also present in the astrocytes from the perikarya to the processes including the perivascular glia limitans. Oligodendrocytes and microglia were immunonegative for CD38. The pattern of distribution of CD38 in the CNS is suggestive of multiple roles for this molecule at various functional sites in both neurons and astrocytes.

ADP-ribosyl Cyclase↗

PubMed1997

Bone mineral measurement in Japan.

Various methods for evaluating bone mineral in appendicular, and axial bone or in the whole skeleton have recently become available. As bone mineral is one of the major determinants of bone strength, its exact measurement should be useful for the diagnosis of osteoporosis, as well as for the prediction of fracture risk and monitoring of therapeutical response. The aims of this paper are to review the fundamental performance of bone mineral measurements, the improvements in DXA systems, and the progress in site-specific bone mineral instruments for the radius and calcaneus used in Japan, and to introduce diagnostic criteria for primary osteoporosis, and report on annual rates of bone loss in Japanese females.

Absorptiometry, Photon↗

PubMed1997

Heat shock protein 72 level decreases during sleep in patients with obstructive sleep apnea syndrome.

Patients with obstructive sleep apnea syndrome (OSAS) suffer from stresses related to repetitive apneas during sleep. To examine whether the level of 72 kDa heat shock protein (HSP72) increases during sleep, 11 OSAS patients (apnea-hypopnea index: 63.5 +/- 36.1, mean +/- SD) underwent polysomnography and their peripheral blood mononuclear cells (PBMC) were isolated before, during, and after sleep. HSP72 level was determined by Western blotting and hsp72 mRNA level was quantified by Northern blotting. Nine normal subjects without OSAS were examined as normal controls. HSP72 level decreased progressively during sleep and its level at 8:00 A.M. was 78.0 +/- 17.5% of that at 8:00 P.M. (p < 0.01). No such decrease was seen in normal subjects. When OSAS patients received nasal continuous positive airway pressure (NCPAP) therapy, HSP72 level did not decrease significantly. In untreated OSAS patients, hsp72 mRNA level decreased during sleep (p < 0.01). When OSAS patients were treated with NCPAP therapy, the decrease in hsp72 mRNA level was not observed. HSP72 level before sleep in OSAS patients was higher than that in normal subjects (p < 0.01). We concluded that repetitive apneas caused high HSP72 level before sleep in OSAS patients and that NCPAP therapy had significant effect on HSP72 levels during sleep.

Blotting, Northern↗

PubMed1997

Hypoxic ventilatory response and breathlessness following hypocapnic and isocapnic hyperventilation.

STUDY OBJECTIVES: To investigate the etiology of posthyperventilation (post-HV) hypoxemia following voluntary hyperventilation (VHV), we examined the effects of hypocapnic (hypo-CO2) and isocapnic (iso-CO2) VHV on the hypoxic ventilatory response (O2-response) and on the sensation of breathlessness during the O2-response. METHODS: O2-responses and visual analog scale (VAS) scores for estimating breathlessness in 10 normal subjects during the O2-response under iso-CO2 conditions and under hypo-CO2 conditions immediately following voluntary maximal HV of 3 min duration were examined. RESULTS: Although there was no significant difference in the post-HV ventilation levels following hypo-CO2 vs iso-CO2 VHV, the VAS scores at the start of the O2-response following hypo-CO2 VHV (30.2+/-24.2 mm) were significantly higher (p<0.05) than the VAS scores at the start of the O2-response following iso-CO2 VHV (13.7+/-8.4 mm). However, VHV did not have a significant effect on the O2-response at 2 min after the VHV when the arterial O2 saturation (SaO2) was below 90%. The nonsteady-state hypo-CO2 induced by VHV greatly attenuated the O2-response below 90% SaO2 and VAS scores at 70% SaO2. CONCLUSIONS: Elevated VAS scores immediately following the hypo-CO2 VHV, which might be independent of actual breathing levels, and the attenuation of the O2-response following the hypo-CO2 VHV were not due to input from lung and chest wall mechanoreceptors induced by the hyperpnea itself, but rather to the hypo-CO2 induced by hyperpnea.

Adult↗

PubMed1997

Ventilatory support during exercise in patients with pulmonary tuberculosis sequelae.

STUDY OBJECTIVE: The aim of this study was to determine whether intermittent positive pressure ventilation through a nasal mask (NIPPV) applied during exercise in patients with pulmonary tuberculosis sequelae (PTS) could improve arterial blood gas measurements, ameliorate breathlessness, and increase exercise endurance. PATIENTS: Seven PTS patients with a severe restrictive ventilatory defect (mean [SD] vital capacity, 1.02 [0.25] I) enrolled in this study had experienced NIPPV previously, and were familiar with the procedure. DESIGN: The patients underwent four constant-load cycle ergometer tests in the supine position to tolerance. The tests were performed with and without NIPPV, while breathing normoxic air (Air) or supplemental oxygen (O2; 35%). NIPPV was delivered during exercise in a controlled, volume-cycled mechanical ventilation mode, and the ventilator settings were modulated manually to meet patients' respiratory demands as estimated from the airway pressure waveform and the patient's breathlessness. RESULTS: All patients matched their breathing to the ventilator cycle during most of the exercise while receiving NIPPV. NIPPV significantly prolonged their exercise endurance time, from a mean (SD) of 180 (58) s to 310 (96) s in Air, and from 227 (64) s to 465 (201) s in O2. During exercise, NIPPV effectively decreased their breathlessness and significantly improved arterial blood gas measurements. CONCLUSIONS: NIPPV applied during exercise can effectively support ventilation, significantly ameliorate breathlessness, and consequently improve exercise endurance in patients with PTS.

Aged↗

PubMed1997

Myelinated nerve fibre analysis of the human small splanchnic nerve.

The aim of the present study is to analyse nerve fibres of the human small splanchnic nerve in relation to the ageing process. The analysis was conducted with the use of a new staining method that makes it possible to discriminate various structures of the nervous tissue. An image-analysing digitiser, a microscope with a drawing tube and a personal computer for storing data and performing statistical analyses were employed in this study. We examined 30 human small splanchnic nerves which were taken from cadaver specimens (20 males and 10 females) aged from 44 to 96 years. Our report may provide a first information concerning the ageing process of the human small splanchnic nerve. The results indicate that a decrease in transverse area and perimeter of myelinated axons in one of the important changes occurring in the human small splanchnic nerve with the ageing process.

Adult↗

PubMed1997

Morphometric analyses of axons in the lateral corticospinal tract with ageing process.

Morphometric analyses were carried out to reveal a relation between age and axonal changes in the lateral corticospinal tract (LCST) at the L1 level of the human spinal cord. Histological preparations of the spinal cord were made after embedding in celloidin to stain with Luxol fast blue-periodic acid-Schiff-hematoxylin or Klüver-Barrera methods. The number, average transverse area, total area and diameter of axons of the LCST were counted and measured using an image-analyser combined with a computer. The morphometric analyses revealed that (1) there was a significant decrease in the axonal number of the LCST with age (p < 0.001); (2) the axons were not partially nor completely accompanied by surrounding myelin sheaths, and increased in number with age; (3) the diameter and average area of axons in the LCST became significantly reduced with age (p < 0.01); (4) the total area decreased significantly with age in a unit area of 2,700 microns2; and (5) the circularity ratio showed no significant change with age.

Adult↗

PubMed1997

Assessment of cardiac sympathetic function with iodine-123-MIBG imaging in obstructive sleep apnea syndrome.

UNLABELLED: Iodine-123-MIBG imaging has been used to evaluate myocardial sympathetic function in various cardiac diseases. In patients with obstructive sleep apnea syndrome (OSAS), increased sympathetic activity has been widely recognized, as assessed by measuring the plasma concentration and urinary excretion of catecholamines and by measuring muscle sympathetic nerve activity. However, these measurements are not specific indices of cardiac sympathetic function. Therefore, this study was undertaken to assess cardiac sympathetic function in patients with OSAS using MIBG cardiac scintigraphy. METHODS: This study consisted of 11 patients (10 men, 1 woman; mean age 43 +/- 16 yr) with a diagnosis of OSAS established by polysomnography, and 8 age-matched normal control subjects (7 men, 1 woman; mean age 45 +/- 18 yr). Early (15 min) and delayed (3 hr) planar images were taken after the injection of 111 MBq of [123I]MIBG. The mean counts of the whole heart and the mediastinum were obtained to calculate heart-to-mediastinum count ratios from the early images (H/Me) and from the delayed images (H/Md) and the myocardial washout rate (WR). Eight patients were restudied after 1 mo of nasal continuous positive airway pressure treatment. RESULTS: The H/Me and H/Md ratios were significantly lower in the patients than in the control subjects (H/Me, 2.49 +/- 0.32 versus 2.84 +/- 0.34, p = 0.0207; and H/Md, 2.33 +/- 0.30 versus 3.02 +/- 0.36, p = 0.0013). The WR was higher in the patients than in the control subjects (36.2 +/- 9.0% versus 23.6 +/- 4.9%, p = 0.0022). The H/Me and H/Md ratios in the patients were significantly correlated with the apnea-hypopnea index and the degree of hypoxemia during sleep. After treatment, H/Me and H/Md remained unchanged, but WR significantly recovered (from 34.9 +/- 10.4% to 26.3 +/- 7.7%, p = 0.0357). CONCLUSION: Cardiac sympathetic function and integrity are impaired in subjects with OSAS when compared with age-matched control subjects. MIBG cardiac imaging can be helpful in evaluating cardiac involvement and efficacy of therapy in OSAS.

3-Iodobenzylguanidine↗

PubMed1997

[Effects of topical application of adrenergic agents on refraction and accommodation].

In an attempt to clarify the functional role of adrenergic receptors on accommodation, effects of various adrenergic agents on the state of accommodation were studied. Fifty-two emmetropic normal subjects (age: 19-28 y) participated in this study. We examined the effect of the alpha agonist phenylephrine hydrochloride (5%), the alpha 1 antagonist adrenergic bunazosin hydrochloride (0.1%), the beta antagonist timolol maleate (0.5%), the beta 2 antagonist betaxolal hydrochloride (0.5%), and the beta agonist isoproterenol hydrochloride (3%). Using an infrared optometer, the refraction, far point and near point of accommodation, resting point of accommodation (empty-field accommodation and dark focus of accommodation), and accommodative adaptation were measured before and after topical application of various adrenergic agents. Application of bunazosin slightly but significantly decreased the near point of accommodation. Isoproterenol evoked a hyperopic shift on the far point of accommodation. None of the agents had any effect on the resting point of accommodation. Accommodative adaptation was increased by timolol and betaxolol, and decreased by isoproterenol. We surmised that beta adrenergic agents exerted an indirect influence on the parasympathetic nervous system. The activation of beta receptors produced a hyperopic shift on the far point of accommodation and decreased accommodative adaptation, which suggests that activation of adrenergic receptors may reduce parasympathetic activity, hence affecting the state of accommodation.

Accommodation, Ocular↗

PubMed1997

[Compartment analysis of 123I-iomazenil brain on early and delayed SPECT].

We investigated the characteristics of 123I-Iomazenil (IMZ) SPECT images in 12 adults (six males and six females, with a mean age of 56.1 years). The washout rate of 123I-IMZ from the brain was estimated from two SPECTs done 15 min and 3 hr after injection. Although the washout was relatively slow, the rates differed in each intracerebral region, suggesting that the distribution of 123I-IMZ was gradually changing. Furthermore, assuming 123I-IMZ kinetics in the brain for the three-compartment, two-parameter model, the transition rate constant (K1) from the blood to the brain and the binding potentials (BP) of benzodiazepine to the receptor were calculated. The BP and K1 values were compared with 123I-IMZ SPECT counts and CBF values by 123I-IMP. The BP values correlated more closely with the counts on the delayed SPECT than those on the early SPECT. It was confirmed that delayed SPECT images reflect better the distribution of the benzodiazepine receptor than early images do. On the other hand, the K1 values correlated highly with CBF obtained by 123I-IMP, and this finding suggested that super-early SPECT images might be remarkably influenced by the distribution of CBF.

Adult↗

PubMed1997

[Evaluation of clinical utility of 111In-DTPA-IgG scintigraphy in the detection of inflammation/infection--a report of multicenter phase III clinical trials].

This is the report of phase III study to evaluate the safety and utility of 111In-DTPA-IgG in patients with strongly suspected inflammation/infection. One hundred and forty five patients with suspected sites of inflammation/infection were enrolled in the study. Only a few adverse experiences in one patient were reported, which were interpreted as having a possible relationship to the agent. A total of 171 suspected sites (12 in head and neck, 39 in thorax, 44 in abdomen and pelvis, 62 in musculoskeletal system, and 14 in other regions) were evaluated by investigators at each institute. Out of 171 sites, 18 were determined to be unevaluable, and 12 false negative and 5 false positive cases were observed. Overall sensitivity and specificity was 89.8% and 85.7%, respectively, and the agent proved to be effective in detecting lesions anywhere throughout the body. The analysis of data from this Phase III study indicates that 111In-DTPA-IgG is well-tolerated in patients and effective in determining focal sites of inflammation/infection although the physiological accumulation in some tissues such as the sinus or liver and possible excretion into the gastrointestinal tract may make it difficult to localize lesions.

Aged↗

PubMed1997

[Comparative study on the tumor accumulation of 99mTc-tetrofosmin and 99mTc-MIBI in rabbits bearing VX-2 cancer].

Each of myocardial blood flow imaging agents has a potential usefulness as an agent for tumor scintigraphy. The tumor accumulation and washout of 99mTc-tetrofosmin and 99mTc-MIBI were comparatively studied using rabbits bearing VX-2 cancer. From seventeen to twenty days after the implantation of VX-2 cancer into the femoral region of seven rabbits, tumor to soft tissue accumulation ratio (T/S ratio) of each agent was calculated in early images (5 min after injection) and in late images (50 min after injection). Compared with 99mTc-tetrofosmin, the T/S ratio of 99mTc-MIBI was higher and, moreover, the washout was delayed. These results suggest that there is a difference in tumor accumulation property between these two agents.

Animals↗

PubMed1996

Some unusual responses of astrocytes to ghost tangles in a long duration case of juvenile Alzheimer's disease: an electron microscopic study.

The ghost tangles (GTs) in usual Alzheimer's disease are separated into small bundles of abnormal straight filaments by many invading astrocytic processes lacking a basal lamina (BL). An electron microscopic study of GTs in the Ammon's horn of a case of juvenile Alzheimer's disease of 25 years' duration, however, revealed that only a small number of astrocytic processes had infiltrated the GTs, resulting in the GTs being composed of large bundles. Moreover, the majority of glial processes that had invaded or apposed GTs possessed an interrupted but still fairly well-developed BL with hemidesmosome-like profiles. Although pia-arachnoid cells are required for astrocytes to form a continuous BL, astrocytes can have a segmental BL on their surface facing even empty intercellular spaces within the brain parenchyma. The much greater frequency and better development of the GT-associated BL in our case indicate that the GT filaments somehow increased the ability of astrocytes to form a BL. On the other hand, the scarcity of GT-invading astrocytic processes implies that many of the glial processes that had once penetrated GTs had been withdrawn, with the result that GTs escaped expectable endocyto-phagocytosis by astrocytes.

Alzheimer Disease↗

PubMed1996

Gallium 67 scintigraphy as a predictor of renal prognosis in primary immunoglobulin A nephropathy.

From October 1987 to September 1989, 29 patients with newly diagnosed immunoglobulin A nephropathy underwent renal gallium 67 scintigraphy. The radioisotope uptake ratio between left kidney and soft tissue was measured 48 hours after bolus injection of gallium 67. In 25 patients the ratio ranged from 1.30 to 3.56 (mean, 1.95 +/- 0.47). Ratios were not obtained in four patients because strong gastrointestinal isotope excretion. Plots of reciprocal serum creatinine concentration against time and Kaplan-Meier plots of renal survival were used to assess the predictive value of the test in 20 patients for whom long-term follow-up data were available. The radioisotope uptake ratio was negatively correlated with the slope of reciprocal serum creatinine against time (r = -0.64, P < 0.01). When the 20 patients were divided into two groups according to radioisotope uptake ratio (group A, ratio > 1.95, nine patients; group B, ratio < 1.95, 11 patients), life table analysis of renal survival showed group B to have a better prognosis than group A (P < 0.05). The results indicate that increased renal gallium uptake is predictive of a poor prognosis in patients with immunoglobulin A nephropathy.

Adult↗

PubMed1996

I-123 iodoamphetamine scintigraphic detection of bone metastases from malignant melanoma.

Widely used for cerebral perfusion imaging, I-123 iodoamphetamine (I-123 IMP) is also known to accumulate in malignant melanomas. A case of malignant melanoma is presented, in which I-123 IMP scintigraphy was useful to visualize the bone metastases. During the period of postoperative follow-up, multiple foci of increased I-123 IMP uptake appeared in the skeleton. Conventional bone scintigraphy was less striking, showing cold defects or irregular radionuclide uptake.

Amphetamines↗

PubMed1996

Inhibitory effect of an intellectual task on breathing after voluntary hyperventilation.

We investigated the effects of an intellectual task on posthyperventilation (PHV) breathing by using a video game. Eight normal subjects were placed in a supine positions. The game task by itself led to increase ventilation compared with the control tasks via an increase in the average inspiratory flow rate (P < 0.01) and the respiratory frequency (P < 0.001). After hypocapnic voluntary hyperventilation (VHV), the task led to a decrease in the 1-min PHV breathing level compared with the control tasks after VHV [after VHV, first 60 s average minute ventilation while watching television and while playing a video game are 5.54 +/- 2.91 (SD) and 2.05 +/- 1.40 l/min, respectively; P < 0.01]. Only one subject showed PHV apnea for at least 10 s during the control protocol, whereas seven of the same eight subjects showed PHV apnea while performing the task. After isocapnic VHV, the task still led to a decrease in PHV breathing compared with the control tasks. However, this decrease was smaller than in the hypocapnic studies and was only significant during the first 15 s of recovery. These results suggest that increased activity in the higher centers of the central nervous system has an inhibitory effect on PHV breathing at a time when the effects of short-term potentiation after VHV, hypocapnia, and perhaps other mechanisms would be expected to be acting on breathing.

Adult↗