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Biomedical subjects

N Yamada

Publications and source records attributed to N Yamada.

At least 613 records · Page 34Linked to original sources
PubMed1991

The role of gallium-67 imaging in the detection of foci in recent cases of fever of unknown origin.

We have assembled data from patients with fever of unknown origin who underwent gallium scintigraphy during the past 5 years in order to obtain a more current sampling of patients, and evaluated the role of gallium scintigraphy retrospectively. Of the 36 patients studied, gallium scintigraphy was positive and contributed to the detection of the foci or fever origins in 17 (47.2%). The ratio of neoplastic diseases with myeloproliferative and with lymphoproliferative disorders was relatively high compared with previous reports. However, gallium scintigraphy did not contribute to the diagnosis of collagen disease. With the ability to detect both inflammatory and neoplastic lesions, gallium scintigraphy was useful in detecting the foci of fevers of unknown origin.

Adolescent↗
PubMed1991

Nifedipine has paradoxical effects on the development of kindling but not on kindled seizures in amygdala-kindled rats.

The effects of nifedipine, an antagonist of voltage-operated calcium channels, on the development of amygdala kindling and on the production of fully kindled seizures, stimulated from the amygdala, were investigated. Rats were treated daily with two doses (5 and 50 mg/kg, i.p.) of nifedipine during the development of kindling. Both doses of nifedipine retarded the development of kindled seizures and 50 mg/kg of nifedipine prolonged the latency to the occurrence of bilateral forelimb clonus. In contrast to these antiepileptogenic effects, however, both doses also increased the duration of afterdischarge. This resulted in a striking increase in the cumulative duration of afterdischarge, required to reach stage 4 and 5 seizures. Contrary to the results of a previous study, 50 mg/kg of nifedipine did not produce any significant effect on fully kindled seizures, regardless of the interval (5 min-24 hr) between injection and stimulation of kindling. These results suggested that although nifedipine inhibited the propagation processes of seizures during development of kindling, it appeared to increase the duration of epileptic activity at the kindling focus.

Action Potentials↗
PubMed1991

Motor activity correlates negatively with free-running period, while positively with serotonin contents in SCN in free-running rats.

Free-running period of blinded rats kept in a cage with a running wheel varied markedly, while it varied little in rats kept in a cage without a running wheel. The mean free-running period of the former group is significantly shorter than that of the latter. In the former, the free-running period correlated negatively with motor activity, indicating that activity affects the free-running period. In both groups, essentially similar diurnal patterns of biogenic amines and their metabolites were observed in various discrete areas in the brain examined. However, there was a significant difference between the two groups in several areas. In the SCN, 5-HT content correlated positively with motor activity, consequently correlated negatively to the free-running period at 3 out of 4 sampling times over 24 h but no such correlation was observed in other monoamines and their metabolites examined. These facts suggest that 5-HT may be associated with modification of the free-running period.

Animals↗
PubMed1991

Superoxide is involved in the pathogenesis of paraquat-induced injury in cultured rat liver slices.

We examined whether superoxide is a factor responsible for paraquat-induced liver injury in terms of superoxide dismutase using cultured rat liver slices exposed to various concentrations of paraquat. The degree of liver injury was assessed by measurement of percentage of lactate dehydrogenase leakage into the medium and lipid hydroperoxides in the liver slices and by direct histopathological observation. Paraquat produced concentration- and time-related liver injury in the cultured rat liver slices. Notably, after exposure to 5 mmol/L paraquat, a significant increase of the percentage of lactate dehydrogenase leakage occurred from 4 hr (p less than 0.05 vs. control group), and this gradually increased up to 8 hr (p less than 0.01 and p less than 0.001 vs. control group at 6 and 8 hr, respectively). Changes in lipid hydroperoxides in the liver slices were similar to those in percentage of lactate dehydrogenase leakage (p less than 0.05 and p less than 0.01 vs. control group at 6 and 8 hr, respectively). Liver injury was located around the central vein at 6 hr and gradually spread at 8 hr. Paraquat-induced liver injury was aggravated both biochemically and histopathologically by pretreatment with 5 mmol/L diethyldithiocarbamate, an inhibitor of copper- and zinc-containing superoxide dismutase activity (percentage of lactate dehydrogenase leakage: p less than 0.01 and p less than 0.001 vs. paraquat group at 6 and 8 hr, respectively; lipid hydroperoxides: p less than 0.01 vs. paraquat group at 8 hr). Incubation of liver slices with liposome-encapsulated superoxide dismutase increased the augmentation of superoxide dismutase in the liver slices.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

18q-syndrome with cleft lip and palate. A clinically diagnosed case.

A case of a child with 18q-syndrome was encountered. The patient presented cleft lip and palate, narrow auditory canals, overlapping fingers, undescended testes and micropenis. Chromosome analysis demonstrated partial deletion of the long arm of one chromosome 18 in the patient and normal chromosomes in the parents. A cheiloplasty for repair of bilateral complete cleft lip was performed.

Chromosome Aberrations↗
PubMed1991

Oral sorbent suppresses accumulation of albumin-bound indoxyl sulphate in serum of haemodialysis patients.

Serum indoxyl sulphate, which is markedly accumulated in haemodialysis patients, cannot be removed efficiently by haemodialysis due to its albumin-binding property. To determine whether an oral adsorbent (AST-120) can decrease its serum concentration, AST-120 was administered to haemodialysis patients. The patients given AST-120 showed significantly reduced serum concentration of indoxyl sulphate as compared to control haemodialysis patients, even though the serum concentrations of urea nitrogen and creatinine did not decrease significantly in the patients treated with AST-120. The haemodialysis patients with generalised pruritus showed an amelioration of itching after administration of AST-120. These results showed that AST-120 was effective in reducing the serum concentration of albumin-bound indoxyl sulphate in haemodialysis patients by adsorption of indole, a precursor of indoxyl sulphate, in the intestines, and that it relieved itching in haemodialysis patients with generalised pruritus.

Administration, Oral↗
PubMed1991

Lymphoscintigraphic assessment of leg oedema following arterial reconstruction using a load produced by standing.

Lymphoscintigraphy using a test involving standing from a supine position and performed following an intradermal injection of 99Tcm-human serum albumin (HSA) was developed to evaluate the function of the lymphatic system in the lower extremities of patients who developed lymphoedema following arterial reconstructive surgery. In normal subjects, the load produced by standing tended to increase lymphatic function as indicated by the frequent appearance of a large spiking wave and a rapid stepwise increase in tracer activity and, less often, a phase of decreasing tracer activity. However, there was either no or less activation of lymph flow following standing in the group which developed leg oedema postoperatively. These findings indicate that lymphatic disruption is responsible for the leg oedema seen in these patients. Performance of this test following an intradermal injection of 99Tcm-HSA is technically simple, requires no special apparatus, and can be completed in 30 min. Lymphoscintigraphy using our new method can provide useful information on abnormalities in lymphatic function.

Aged↗
PubMed1991

Heterogeneous mutations in the human lipoprotein lipase gene in patients with familial lipoprotein lipase deficiency.

The DNA sequences were determined for the lipoprotein lipase (LPL) gene from five unrelated Japanese patients with familial LPL deficiency. The results demonstrated that all five patients are homozygotes for distinct point mutations dispersed throughout the LPL gene. Patient 1 has a G-to-A transition at the first nucleotide of intron 2, which abolishes normal splicing. Patient 2 has a nonsense mutation in exon 3 (Tyr61----Stop) and patient 3 in exon 8 (Trp382----Stop). The latter mutation emphasizes the importance of the carboxy-terminal portion of the enzyme in the expression of LPL activity. Missense mutations were identified in patient 4 (Asp204----Glu) and patient 5 (Arg243----His) in the strictly conserved amino acids. Expression study of both mutant genes in COS-1 cells produced inactive enzymes, establishing the functional significance of the two mis-sense mutations. In these patients, postheparin plasma LPL mass was either virtually absent (patients 1 and 2) or significantly decreased (patients 3-5). To detect these mutations more easily, we developed a rapid diagnostic test for each mutation. We also determined the DNA haplotypes for patients and confirmed the occurrence of multiple mutations on the chromosomes with an identical haplotype. These results demonstrate that familial LPL deficiency is a heterogeneous genetic disease caused by a wide variety of gene mutations.

Adolescent↗
PubMed1991

Binding of viral glycoprotein with trypsin and its relation to virulency. I. Initial step of binding.

The interaction between surface proteins of some enveloped viruses and trypsin was studied by computer analysis. Prior to the cleavage of the viral protein by trypsin, hydrophobic interaction between them at the vicinity of their active sites may occur. An exposed hydrophobic portion was found there which theoretically could stimulate the interaction. This interaction would be rather non-specific: according to the analysis, trypsin could bind equally well with weakly virulent virus and virulent viruses. Following this interaction, a specific reaction between their active sites would occur. The specificity was found to be related to the virulency of the virus.

Amino Acid Sequence↗
PubMed1991

Studies on glycolipids. III. Glyceroglycolipids from an axenically cultured cyanobacterium, Phormidium tenue.

Seven new monogalactosyl diacylglycerols (1-7) and six new digalactosyl diacylglycerols (11-16) were isolated from an axenically cultured cyanobacterium, P. tenue. Their structures were elucidated on the basis of physicochemical evidence and the results of enzymatic hydrolysis using a lipase (from Rhizopus arrhizus). Comparison of antialgal activity for P. tenue between monogalactosyl diacylglycerols (1-8) and digalactosyl diacylglycerols (11-19) revealed that the former showed more potent activity than the latter.

Cyanobacteria↗
PubMed1991

Synthesis and antitumor activities of novel benzoylphenylurea derivatives.

Seventy novel benzoylphenylurea compounds were synthesized and their antitumor activities were examined in vivo against P388 leukemia. N-(2-Nitrobenzoyl)-N'-[4-(2-pyrimidinyloxy)phenyl]ureas showed the highest antitumor activities when dosed intraperitoneally or orally. Their structure-activity relationships were examined with particular focus on the position and the variety of substituent on each aryl ring.

Animals↗
PubMed1991

Image analysis of microsialograms of the mouse parotid gland using digital image processing.

We compared two digital-image feature-extraction methods for the analysis of microsialograms of the mouse parotid gland following either overfilling, experimentally induced acute sialoadenitis or irradiation. Microsialograms were digitized using a drum-scanning microdensitometer. The grey levels were then partitioned into four bands representing soft tissue, peripheral minor, middle-sized and major ducts, and run-length and histogram analysis of the digital images performed. Serial analysis of microsialograms during progressive filling showed that both methods depicted the structural characteristics of the ducts at each grey level. However, in the experimental groups, run-length analysis showed slight changes in the peripheral duct system more clearly. This method was therefore considered more effective than histogram analysis.

Animals↗
PubMed1991

Melatonin secretion in normal pressure hydrocephalus after cerebral aneurysm rupture--investigation before and after ventriculoperitoneal shunt.

Melatonin (MLT) secretion was examined in six normal pressure hydrocephalus (NPH) patients before and after ventriculoperitoneal (VP) shunt surgery. Ten healthy subjects were used as controls. Venous blood samples were taken daily at 2 p.m., 8 p.m., 2 a.m., and 8 a.m. Radioimmunoassay of MLT used a new specific antiserum and separation method achieving low cross-reactivity and high-efficiency MLT separation. Plasma levels in the control group at 2 p.m. and 2 a.m. were significantly different, showing diurnal rhythm (DR). The patients' MLT levels before VP shunt were significantly lower than control levels and the DR was absent. Postoperatively, the values were significantly different from preoperative values only at 2 a.m., but the DR reappeared. Thus, in NPH, VP shunt surgery improved the melatonin DR, probably through normalization of the dilated third ventricle.

Adolescent↗
PubMed1991

"Designer" amphetamines: effects on behavior and monoamines with or without reserpine and/or alpha-methyl-para-tyrosine pretreatment.

Rats were given single injections of vehicle or one of three doses of (+)-amphetamine (AM), 4-methoxyamphetamine (MA) or 4-ethoxyamphetamine (EA) after pretreatment with vehicle or reserpine, and vehicle or alpha-methyl-para-tyrosine (AMPT). EA is a "designer" drug that was recently seized from an illicit laboratory in Canada. Locomotion of the rats was recorded after treatment with the drugs, and whole brain levels of the drugs as well as monoamine neurotransmitters and their major acidic metabolites were then determined. Neither of the ring-substituted AM analogues influenced locomotion. AM induced locomotion in a dose-dependent manner, and this effect was blocked by AMPT but potentiated by reserpine. Brain concentrations of EA were lower than those of the other two drugs. The brain levels of monoamines and their metabolites indicate that AM releases a newly synthesized pool of dopamine which is transferred to vesicles after re-uptake. A very low dose of AM, but not higher doses, was found to elevate serotonin (5-hydroxytryptamine: 5-HT) levels independently of effects on catecholamines. Both MA and EA affected monoamine metabolites in a manner consistent with actions as reversible inhibitors of monoamine oxidase-an effect which has been previously demonstrated to be true for MA. Both drugs increased 5-HT levels at a very low dose, as did AM, but also increased noradrenaline levels at this dose. It is concluded that EA is not a psychomotor stimulant, but is similar in many of its effects to MA, a potent hallucinogen.

Amphetamines↗
PubMed1991

[Hyperkinésie volitionnelle following head injury].

A 13-year-old girl was struck by a car while riding her bicycle. She was comatose on her arrival at the hospital. Neurological examination revealed no focal sign except for right oculo-motor palsy. She became alert 15 days after the head injury when she first experienced a coarse tremor-like movement on the right arm. Neurological examination showed persistent oculo-motor palsy on the right side, decreased sensation of pain and touch on the left. There was no pyramidal deficit. Her gait and speech were normal and joint sensation was intact. A coarse tremor of the right arm was induced by volitional movements especially such as maintaining the arm in certain posture. It was not present at rest. Trajectory of finger-to-nose test was fairly well. However, the tremor became worse when the patient kept her finger near the target. Occasionally myoclonic-jerk and movement oppositionniste were mixed. Superficial EMG recordings of the tremor revealed 4 c/s rhythmic reciprocal grouping discharges, alternating flexor and extensor muscles. From these features, the abnormal movement should better be called tremor type of hyperkinésie volitionnelle (HV). The HV subsided spontaneously 4 months later. MRI of T2-weighted image showed high-intensity areas corresponding anatomically to the caudal part of right red nucleus and the right superior cerebellar peduncle just before its decussation. It is widely believed that lesions in cerebellar outflow pathway (i.e. dentate, red nucleus and thalamus) can cause HV.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1991

[The appearance of "lambda" and "panda" sign on Ga-67 scintigraphy in sarcoidosis].

The lesions of sarcoidosis generally show relatively high Ga-67 uptake and the usefulness of scintigraphy using this agent in the evaluation of lesion activity is well known. In this report, we assessed characteristic uptake of Ga-67 in intrathoracic lymphnodes, the shape of which resembled the Greek letter Lambda (Lambda sign) and a symmetrical accumulation in bilateral lacrimal and salivary glands which resembled a Panda face (Panda sign) in patients with sarcoidosis. Our review of Ga-67 scans obtained from 15 patients with sarcoidosis and 1,779 patients with other disorders during the past 3 years revealed that the simultaneous presence of both Lambda and Panda signs was specific to patients with sarcoidosis and was not found in patients with various other disorders, although one of these signs might be observed in patients without sarcoidosis. When Lambda-like sign was observed, chest radiogram or CT was necessary for the differential diagnosis of sarcoidosis. Panda sign was observed frequently among patients who had previously received irradiation of the neck. Our results confirmed that sarcoidosis must be suspected when both Lambda and Panda signs were observed.

Adult↗