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Biomedical subjects

T Hamada

Publications and source records attributed to T Hamada.

At least 379 records · Page 21Linked to original sources
PubMed1994

Multifocal eosinophilic granuloma presenting as progressive brainstem and cerebellar dysfunction.

A 55 year old woman with multifocal eosinophilic granuloma (MEG) is described. She developed facial numbness and twitching followed by slowly progressive cerebellar symptoms. Two years later polyuria and polydipsia were noted. A CT of the brain showed multifocal enhancing lesions, and MRI showed areas of hyperintensity on T2 weighted studies in the cerebellar peduncles, pons, and midbrain. Radiographs of the skull, pelvis, and long bones were normal, but a 99mTc diphosphonate bone scan and MRI showed bone lesions compatible with granuloma. The diagnosis of MEG was made by bone biopsy. This is believed to be the first case of MEG with such unusual clinical profiles and radiographical findings. Skeletal surveys are indicated for patients with unexplained focal or multifocal inflammatory changes in the cerebellum.

Biopsy↗
PubMed1994

N-methyl-D-aspartate induces phase shifts in circadian rhythm of neuronal activity of rat SCN in vitro.

The suprachiasmatic nucleus (SCN) acts as a pacemaker for mammalian circadian rhythms. Receptors for excitatory amino acids like N-methyl-D-aspartate (NMDA) and non-NMDA receptors have both been found to play an important role in the transmission of photic information from the retina to the SCN. Therefore, we investigated whether the application of glutamate receptor agonists could reset the phase of the circadian rhythm of SCN firing activity in vitro. Treatment with NMDA (0.1-10 microM) for 15 min or 1 h during the early part of the subjective night produced phase delay, whereas treatment during the late subjective night caused an advance in phase. The phase-response curve for NMDA was similar to that previously obtained in response to light pulses in vivo. Application of DL-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid hydrobromide (AMPA) (1 or 10 microM), a non-NMDA-receptor agonist, also produced a dose-dependent phase delay of SCN activity. The NMDA-induced phase delay was antagonized by an NMDA-receptor antagonist MK-801. These findings suggest that both NMDA and non-NMDA receptors may be involved in the transmission of information to the SCN via the retinohypothalamic tract. In addition, both the advances and delays in phase caused by NMDA were potentiated by cotreatment with neuropeptide Y, whereas AMPA-induced phase delay was not potentiated by neuropeptide Y. This points to a functional link between NMDA and neuropeptide Y receptor-mediated mechanisms in the SCN.

Animals↗
PubMed1994

Cytopathological changes induced by cadmium-exposure in canine proximal tubular cells: a cytochemical and ultrastructural study.

A highly sensitive cytochemical method for demonstrating intracellular Cd using 8-hydroxyquinoline was developed and applied in the cytopathological study of primary-cultured renal tubular cells from beagle kidneys. The Cd-8-hydroxyquinoline emitted a yellowish-green fluorescence which first appeared in the cytoplasm within 30 min and in the nucleus about 60-90 min after exposure to 100 mM CdCl2. It was noteworthy that intranuclear Cd was stained in the nucleolar regions. The sensitivity of the cytochemical method for Cd was estimated to be about 1.0 pg Cd/cell. Ultrastructural features of the dead cells were consistent with those of apoptosis. We conclude that Cd absorbed by proximal tubular cells rapidly reaches to the nuclei and affects nuclear as well as cytoplasmic metabolism.

Animals↗
PubMed1994

Temporal frequency deficit in patients with senile dementia of the Alzheimer type: a visual evoked potential study.

To study the temporal aspect of visual processing of senile dementia of the Alzheimer type (SDAT), we recorded the steady-state visual evoked potentials (VEPs) to LED goggle stimulation at five different temporal frequencies in 14 patients with SDAT and 14 control subjects. For comparison, we also studied 14 patients with vascular dementia (VD). All subjects were women, and their ages were closely matched. Temporal frequencies were 5, 10, 15, 20, and 30 Hz. The steady-state VEPs were Fourier analyzed, and both the amplitude and phase of the first and second harmonic responses were obtained. There was a significant difference in the amplitude across the three groups for stimulation at 15, 20, and 30 Hz, but no difference at a stimulation of 5 and 10 Hz. Multiple comparison tests revealed that patients with SDAT had a significantly smaller amplitude than normal controls. Patients with VD had lower amplitudes than normal subjects, but this was not statistically significant. In the phase data, there were also no statistically significant differences across the three groups for any of the temporal frequencies. These results indicate that a temporal frequency deficit exists in SDAT. This phenomenon may be explained by the pathology that affects the early stage of visual signal processing.

Aged↗
PubMed1994

Sequential magnetic resonance features of encephalopathy induced by systemic mastocytosis.

A 37-year-old man developed encephalopathy with prominent eosinophilia. Magnetic resonance imaging (MRI) revealed multiple T2-weighted high signal intensity lesions with dimeglumine gadopentetate (Gd-DTPA) enhancement on T1-weighted images, which were distributed in the cerebral cortex, thalamus, deep white matter and cerebellum. He was diagnosed as having systemic mastocytosis on the basis of proliferating mast cells in the bone marrow and peripheral eosinophilia. Following steroid administration, there was a rapid improvement of his symptoms and laboratory data. To our knowledge, this was the first reported case of systemic mastocytosis provoking encephalopathy with serial MRI findings.

Adult↗
PubMed1994

Recurrent generalized lichen nitidus associated with amenorrhea.

A case of recurrent generalized lichen nitidus is reported. The eruptions developed in the proliferative phase of the menstrual cycle, but there has been a marked improvement after administration of estrogen and progesterone for the treatment of amenorrhea. Hormonal factors may play a role in the development of lichenoid tissue reaction in the lesions of this disease.

Adult↗
PubMed1994

Polyhydramnios: ultrasonic detection of fetal and maternal conditions.

Estimation of amniotic fluid volume is an important part of routine obstetric sonography. A relationship between polyhydramnios and poor perinatal outcome has been reported. This study correlates the severity of polyhydramnios with perinatal morbidity and mortality. Among 67 cases of polyhydramnios detected in singleton pregnancies, 8 were associated with maternal conditions including noninsulin-dependent diabetes (5 cases), insulin-dependent diabetes (1 case) and gestational diabetes (2 cases). Forty-four were associated with fetal conditions, including fetal anomalies (31 cases), fetal chromosomal disorders (10 cases) and fetal functional disorders (3 cases). Fifteen of the 67 cases had no apparent underlying fetal or maternal cause. Perinatal death occurred in 19 cases (28%) and was associated with fetal anomalies (12 cases), chromosome disorders (6 cases) and a functional fetal abnormality (1 case). Severe polyhydramnios with amniotic pocket dimensions > or = 120 mm (91%) or with a need for amniocentesis (91%) were associated with fetal abnormalities in most cases. The rate of perinatal death was not increased, indicating that severe polyhydramnios does not always result in lethal abnormalities.

Female↗
PubMed1994

[Studies on the medicinal plants in the "Sambutsu-cho" of Merayama, belonging to Kuma province, Higo].

The Sambutsu-cho, a list of the natural products, of Merayama, belonging to Kuma Province, Higo was dedicated to the Tokugawa shogunate ca. 1735. This book did not contain so many names, but there were various names of plants, animals and minerals. In the plant kingdom, there were the names of the wild and cultivated plants, such as cereals, vegetables, fruits, trees, bamboos, herbs and mushrooms. The part on trees had 61 names and the other part, on herbs, had 76 names. In this report, I studied the species of the trees and herbs which were listed by their local and standard names. I identified them and found 56 and 63 species, respectively. Among the 56 species of trees, 39 were medicinal plants. Also, 48 medicinal plants were found among the 63 species of herbs. The ratio of medicinal plants to trees and herbs was 70 and 76%. This Sambutsu-cho contained color illustrations of the herbs, trees, animals, birds and insects. These pictures were not always accurate but very much useful to identify the local names in the Edo-period to match them with their scientific names. One of the most interesting samples was "Miso-ushinai." This was identified as Lyonia ovalifolia var. elliptica, Ericaceae.

Books, Illustrated↗
PubMed1994

[A study of the relationship between diabetic neuropathy and diabetic retinopathy].

To evaluate the relationship between diabetic neuropathy and retinopathy, we examined autonomic nervous function, postural hypotension, nerve conduction velocity and coefficient of variation of R-R intervals. Forty-five non-insulin dependent diabetic cases were classified as no diabetic retinopathy (group A), simple diabetic retinopathy (group B) and proliferative diabetic retinopathy (group C). These groups did not differ in age or gender. The rate of postural hypotension (depression of systolic blood pressure over 30 mmHg) was 0% in group A, 7% in group Bs and 53% in group C. Nerve conduction velocity in both motor and sensory nerve was delayed over 20% in 0% of group A, 8% of group B, and 33% of group C. In CVR-R, 11% of group A and 7% of group B were decreased, and 44% (during rest) and 33% (during deep breathing) of group C was decreased. Between groups A and B there was no statistical difference. But group C had statistically significant difference from other groups, particularly in postural hypotension. Peripheral neuropathy might be closely related to diabetic retinopathy.

Adult↗
PubMed1994

[Changes in luminal diameter of internal thoracic arteries five years after coronary artery bypass grafting].

Five years after coronary artery bypass grafting, 23 internal thoracic arteries (ITAs) were reexamined angiographically, and their luminal diameters were compared with those of one month after the operation. Proximal diameter, just below the subclavian artery, and distal diameter, just above the anstomosis, were measured. One month after surgery, these were 2.38 +/- 0.48 mm and 1.69 +/- 0.39 mm, respectively. After five years, the proximal diameter had not changed significantly (2.48 +/- 0.47 mm), but the distal diameter had increased to 1.96 +/- 0.58 mm (p < 0.05). Especially when there was no competitive flow with the ITA, the distal diameter showed a marked increase from 1.80 +/- 0.35 mm to 2.27 +/- 0.42 mm (p < 0.01). Twelve ITAs were grafted to coronary arteries having less than critical stenosis, and five of them showed distal narrowing or so-called string sign after five years. This seemed to be a form or physiological atrophy resulting from competitive flow, and the patients had no anginal pain in spite of their poor ITA runoff. When coronary artery stenosis is less than 75%, a choice is difficult between an ITA or a saphenous vein graft. We think that the graft must be selected considering the possibility of stenosis progression, if the jeopardized area is important for the patient. An ITA graft would be advisable in such cases.

Aged↗
PubMed1994

[Radiological findings of gastric scirrhous cancer].

Gastric scirrhous cancer was classified from the radiological findings into three phases (typical, latent and early phases) by cancerous involvement in the gastric wall. Radiological findings in the typical phase were divided into a giant-fold type and a no giant-fold type. We made a differential diagnosis for scirrhous cancer and other diseases. Radiological findings in the typical phase of scirrhous cancer were characteristic stiffness and rigidity of the gastric wall; in the latent phase, they were swelling and winding of mucosal folds in appropriate distended stomach; and in the early phase, interrupted folds around barium fleck. The effect of chemotherapy against a gastric scirrhous cancer is decided by distensibility of the gastric wall in radiological findings.

Adenocarcinoma, Scirrhous↗
PubMed1994

[Application of the polyglycolic acid (PGA) pledgets or sheet for pulmonary fistulas and defects of the pleura].

A felt-like bioabsorbable prosthesis (Polyglycolic Acid (PGA) pledget and sheet; Medifit feft) was used for pulmonary fistula in a total of 10 patients. "Fibrin glue A" was absorbed into the PGA prosthesis previously. And next, the part of pulmonary fistula was coated with "Fibrin glue B", and then covered with the fibrin-absorbed PGA prosthesis. The prosthesis adhered to the diseased part of pulmonary pleura immediately, and therefore, in all these 10 patients, the post-operative air-leakage was stopped up to 4 days and neither side effect nor complication was observed.

Adult↗
PubMed1994

[Flumazenil antagonism of midazolam-induced respiratory depression].

Flumazenil, a benzodiazepine antagonist, reliably reverses midazolam-induced sedation, but its effect on respiratory depression has not been clarified completely. Ten healthy male volunteers received midazolam 0.1 mg.kg-1. Then they received flumazenil 0.5 mg (n = 9) and 1.0 mg (n = 1), intravenously. Rib-cage (RC) and abdominal wall (ABD) movement was measured by mercury-in-silastic strain gauge. Nasal air flow (FLOW), genioglossal electromyogram (EMG) and oxygen saturation (SaO2) were recorded simultaneously. Midazolam caused significant increases of RC movement and respiratory rate, and decreases of ABD movement, FLOW, EMG and SaO2. After administration of flumazenil, although respiratory rate returned to the pre-midazolam values, RC movement decreased on the contrary. ABD movement, FLOW, EMG, SaO2 did not recover to the pre-midazolam values. These data suggest that flumazenil 0.5 mg reverses midazolam-induced sedation completely, but is partially effective for some parameters related to respiratory depression.

Adult↗
PubMed1994

Immunohistochemical approach for the investigation of nerve distribution in the shoulder joint capsule.

Twenty six shoulder joint capsules obtained from 13 autopsy cases were studied to evaluate the nerve distribution using immunohistochemical techniques. Immunohistochemical staining of polyclonal S-100 protein or protein gene product 9.5 was more sensitive, specific, and reproducible compared with conventional gold chloride methods. A small number of clustered nerve fibers were found in the superficial layer, and many nerve fibers with large diameters were found in anteroinferior portions of the deep layer. Nerve fibers of various sizes were more numerous in posterosuperior and anterosuperior portions of the boundary zone between labrum and capsule. A Pacinian corpuscle was clearly recognized in a capsule. In the central portion of the long head of some biceps brachii tendons, relatively large nerve fibers continued from capsules. The results suggest that the capsule and long head of the biceps brachii tendon may play a partial role in the stability of the shoulder joint through afferent feedback.

Aged↗
PubMed1994

[Clinical effects and safety of granisetron administration against CDDP chemotherapy in lung cancer. Lung Cancer Study Group].

Granisetron (3 mg/body) was administered immediately before single CDDP administration (80 mg/m2 or more) to 53 patients with lung cancer. This chemotherapy was performed a total of 73 times. Concerning Grade 2 or 3 nausea and vomiting, good conditions were observed on day 1 (day of treatment), most marked aggravation on day 2, and initiation of improvement on day 4. Vomiting was slight on day 1, most aggravated on day 2, but began to improve on day 3; good results were generally observed thereafter. Decreased appetite was slight on day 1, but was most aggravated on day 3 and 4; its recovery was delayed even until day 7. In the treatment for delayed emesis, comparison was made among the group treated with granisetron alone who did not require treatment for delayed emesis, the group with delayed emesis treated with granisetron, and the group with delayed emesis treated with drugs other than granisetron. Slightly better results were observed in terms of nausea, vomiting, and the frequency of vomiting in the group treated with granisetron alone on days 2 and 3. However, no significant difference was observed in decreased appetite among the 3 groups. Granisetron had no side effects and was safe. It inhibited vomiting, but measures to improve decreased appetite are needed.

Adult↗
PubMed1994

Brachial plexus block using a nerve stimulator and a conventional needle.

A technique for blocking the brachial plexus using a electrostimulator and conventional, non-special plastic cannula with an obtulator consist of conductive metal is described. This cannula is cheaper and more conventional than special plastic-coated needle. Brachial plexus block is useful anesthesia for surgical treatment of fractures, dislocations, skin and muscle injuries of the forearm and hand. However, the blockade does not seem to be completely reliable because of the anatomical variations among individuals and the consequent difficulty in locating of the brachial plexus. Therefore the method using an electrostimulator and a special plastic-coated needle for the brachial plexus block was reported in 1962 by Greenblatt. Employing a conventional plastic cannula for intravenous use instead of a special plastic-coated needle reported by Greenblatt. We could attain nerve block completely reliably, safely and easily.

Brachial Plexus↗
PubMed1993

Mechanism of chromosomal integration of transgenes in microinjected mouse eggs: sequence analysis of genome-transgene and transgene-transgene junctions at two loci.

Production of transgenic animals is a key technique in modern biology, but the process of chromosomal integration of transgenes in microinjected eggs is still not fully understood. To gain information on the mechanisms involved in this process, we have cloned two transgene loci and their corresponding pre-integration sites and compared the junction sequences with the parental nucleotide (nt) sequences. No extensive DNA rearrangements were detected at these loci: only simple deletions (caused by the integration of the transgene concatemers) were present in the host genome. Analysis of three transgene-transgene junctions within the concatemers showed that 'nibbling' of ends (up to 3 nt) had occurred at some ends prior to joining. At all four genome-transgene junctions, short homologies of 1 to 3 nt were found, and at least three of these junctions were associated with the consensus sequence for topoisomerase-I cleavage sites. Moreover, three of the four integration junctions occurred in the terminal regions of the injected sequence, at positions only a few nt away from the ends. These results suggest that linear, but not circular, concatemers were preferentially integrated at their ends utilizing short homologies to the host genome.

Animals↗