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Biomedical subjects

N Takeda

Publications and source records attributed to N Takeda.

At least 379 records · Page 21Linked to original sources
PubMed1993

[Neurogenic inflammation in nasal hyperreactivity].

The role of neuropeptides in nasal hyperreactivity was examined in guinea pigs by histochemical and pharmacological study. Intranasal application of toluene diisocynate (TDI) induced nasal hyperreactivity symptoms: sneezing and watery rhinorrhea, and decreased histamine content in the nasal mucosa in guinea pigs sensitized with TDI. The immunoreactivity of substance P (SP) and calcitonin gene-related peptide (CGRP) in the nerve terminals in the nasal mucosa was increased after intranasal application of TDI. We also observed a decrease in the immunoreactivity of SP and CGRP, and an increase in their mRNA expression in trigeminal ganglion neurons. These findings indicate that exposure to TDI enhanced the biosynthesis of both SP and CGRP in the trigeminal ganglion neurons and their axonal transportation to the terminals in the nasal mucosa. In animals pretreated with capsaicin before sensitization, TDI did not induce nasal allergy-like behavior and histamine release in the nasal mucosa. Since capsaicin depletes SP and CGRP in the sensory nerves, this finding indicates neuropeptide-mediated histamine release in the nasal mucosa. All these findings suggest that, on exposure to TDI, the antidromic release of SP and CGRP in the nasal mucosa triggers the release of histamine, resulting in the development of symptom of nasal hyperreactivity.

Animals↗
PubMed1993

Molecular design of artificial hydrolytic nucleases and ribonucleases.

Artificial nucleases and ribonucleases, which selectively hydrolyze the specific phosphodiester linkages in DNAs and RNAs, are prepared by the attachment of organic and inorganic catalysts to DNA oligomers as sequence-recognizing moieties. A hybrid of ethylenediamine and a 19-mer DNA selectively hydrolyzes tRNA(Phe) at the 3'-side of C63. Site-selective hydrolysis of DNAs has been accomplished by the lanthanide complexes bound to DNA oligomers. No concurrent oxidative cleavage of the ribose or the deoxyribose takes place.

Base Sequence↗
PubMed1993

Pathophysiology of cardiac dysfunction in congestive heart failure.

Although various factors, such as myocardial infarction, pressure overload and volume overload, result in the development of congestive heart failure (CHF), the pathogenesis of contractile dysfunction in this situation is poorly understood. Loss of cardiac muscle due to myocardial infarction appears to activate several humoral and hormonal pathways, including the renin-angiotensin and sympathetic systems which serve as adaptive mechanisms to maintain cardiovascular performance at early stages of failure. However, under chronic conditions, an altered hormonal profile produces deleterious effects and permits transition from the compensated heart to the failing heart. Since several risk factors--such as hypertension, hypercholesteremia, stress, diabetes, smoking, ageing, obesity and lack of exercise--precipitate ischemic heart disease, it is possible that development of CHF due to myocardial infarction may vary according to the nature of these pathogenetic entities. While a great deal of research work remains in this area of investigation, it is becoming evident that cardiac dysfunction is intimately associated with calcium handling abnormalities of cardiac cells. In view of the role of sarcolemma, sarcoplasmic reticulum and mitochondria in regulating the intracellular concentration of Ca2+ and the importance of myofibrillar interaction with Ca2+, it appears that Ca2+ handling and Ca2+ interaction abnormalities in the failing heart are due to remodelling of different subcellular organelles. Such a remodelling of the subcellular organelles may be due to changes in gene expression for different protein components or the interactions of proteins with phospholipids. Accordingly, it is proposed that new interventions, which could prevent the remodelling of subcellular organelles, be developed for improving the therapy of CHF.

Aged↗
PubMed1992

Effects of regression of cardiac hypertrophy on myocardial contractility and ventricular myosin isoenzymes.

The effects of regression of cardiac hypertrophy on myocardial contractility and ventricular myosin isoenzymes were investigated in rats with renovascular hypertension. Six-week-old male Wistar rats were made hypertensive by constriction of one renal artery with a silver clip. Regression of cardiac hypertrophy was induced following the lowering of blood pressure by nephrectomy on the affected side 5-6 weeks after constriction of the renal artery and was maintained for 5-6 weeks. In contrast, myocardial hypertrophy was induced by 10-11 weeks of the hypertensive state. Isometric developed tension of isolated left ventricular papillary muscles was measured, while they were being perfused with Tyrode solution. Left ventricular myosin isoenzymes were separated by pyrophosphate gel electrophoresis. The ventricular to body weight ratio of the nephrectomized group was significantly lower than that of the hypertensive group, although it was greater than that of age-matched normal control rats. There were no significant differences in the isometric developed tension among three groups, the nephrectomized, hypertensive, and normal control rats. However, dT/dtmax tended to decrease in the hypertensive rats and recovered to normal in the nephrectomized rats. The left ventricular myosin isoenzyme pattern was shifted toward VM-3 in hypertensive rats and was shifted back toward VM-1 again in nephrectomized rats.

Animals↗
PubMed1992

Rapid determination of sulphonamides in milk using liquid chromatographic separation and fluorescamine derivatization.

A simple and selective method is presented for the multiple residue determination of eight sulphonamides in consumers' milk. The drugs are sulphisomidine (ID), sulphadiazine (DZ), sulphamerazine, sulphadimidine, sulphamonomethoxine, sulphamethoxazole, sulphadimethoxine and sulphaquinoxaline (SQ). The milk sample was deproteinized with the same volume of 2 M hydrochloric acid and filtered. A 1-ml volume of the filtrate was mixed with 1 ml each of 1.25 M sodium acetate solution and a buffer (pH 3.0) for derivatization with 0.6 ml of 0.02% fluorescamine solution in acetone. A high-performance liquid chromatographic analysis was carried out on a C18 column with a mobile phase of acetonitrile-2% acetic acid (3:5) at 55 degrees C using a fluorescence detector at an excitation wavelength of 405 nm and an emission wavelength of 495 nm. Average recoveries at fortification levels of 2, 5 and 10 ng/ml were 114%, 109% and 106%, respectively. Relative standard deviations were 1-4% at 10 ng/ml for ID, 5 ng/ml for DZ and SQ and 2.5 ng/ml for the other five sulphonamides. The method was applied to 25 milk samples and all appeared to be free from the drugs.

Animals↗
PubMed1992

Endogenous synthesis of N-methylsalsolinol, an analogue of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, in rat brain during in vivo microdialysis with salsolinol, as demonstrated by gas chromatography-mass spectrometry.

N-Methylsalsolinol, an analogue of 1,2,3,6-tetrahydropyridine, is present in the brains of patients with Parkinson's disease. To determine the metabolic pathway for the synthesis of N-Methylsalsolinol in the brain, salsolinol was perfused through the striatum or the substantia nigra of the rat brain by in vivo microdialysis. N-Methylsalsolinol was detected in the brain dialysate samples during microdialysis with salsolinol using gas chromatography-mass spectrometry with selected-ion monitoring. These results demonstrate that endogenous N-methylation of salsolinol into N-methylsalsolinol occurs in the brain in vivo.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1992

Nasal mucosa sensitization with toluene diisocyanate (TDI) increases preprotachykinin A (PPTA) and preproCGRP mRNAs in guinea pig trigeminal ganglion neurons.

Toluene diisocyanate (TDI) induces respiratory allergy in mammals. Using immunohistochemistry and in situ hybridization histochemistry, the present study examined effects of nasal mucosa sensitization by TDI on the immunoreactivity for substance P (SP) and calcitonin gene-related peptide (CGRP) and on the expression of their mRNAs in guinea pig trigeminal ganglion and their terminals. Single intranasal application of TDI (acute experiment) did not induce nasal allergy-like behaviours and failed to cause changes of SP and CGRP immunoreactivity and in the expression of preprotachykinin A (PPTA) mRNA and preproCGRP mRNA coding for SP and CGRP respectively in the trigeminal ganglion neurons. However, repeated application of TDI (chronic experiment) caused a dramatic increase of SP and CGRP immunoreactivity in peripheral neurites of sensory nerves in the nasal mucosa but a slight increase in the spinal trigeminal nucleus, a decrease of the same immunoreactivities in the cell bodies of the trigeminal ganglion neurons, and an increase of the expression of PPTA and preproCGRP mRNA in the same neurons. These findings suggest that chronic exposure of the nasal mucosa to TDI apparently causes enhancement of both the biosynthesis of SP and CGRP and their axonal transport in the trigeminal system.

Animals↗
PubMed1992

Electrophysiologic findings in optic nerve dysfunction associated with multiple evanescent white-dot syndrome.

Electrophysiologic findings in a case of multiple evanescent white-dot syndrome were studied. A 37-year-old woman presented with multiple white dots, granularity of the macula, and optic disc swelling in her left fundus. The electroretinogram and electro-oculogram revealed abnormal findings indicative of changes in the retinal pigment epithelium and photoreceptors. In addition, relative afferent pupillary defect, enlargement of the blind spot, a decrease in the critical fusion frequency, staining of the optic disc on fluorescein angiography and prolonged latency of the P100 component with decreased amplitude in pattern-reversal visual evoked cortical potential strongly suggested dysfunction of the optic nerve in this patient.

Adult↗
PubMed1992

Correlation of computed tomography with the histopathology of primary malignant lymphoma of the brain.

The authors present seven autopsy cases of non-AIDS primary malignant lymphoma of the central nervous system to correlate the pathology with the findings of the most recent pre-mortem computed tomogram (CT). Of 10 primary contrast-enhancing (CE) lesions treated by chemotherapy alone, radiotherapy alone, radiochemotherapy, or surgery combined with radiochemotherapy, all but one completely disappeared after the initial course of therapy. However, in six of the seven patients, the final pre-mortem CT demonstrated CE lesions. In three cases CE lesions were at the same site as the primary lesion, in one case in a remote location, and in two cases in diffuse and multiple locations. In all but one case these CE lesions corresponded histologically to tumor nodules or to white matter densely infiltrated by tumor cells. The sole exception was diagnosed pathologically as delayed radiation necrosis. The final CT also showed five low-density areas (LDAs) which had evolved from CE lesions after the completion of therapy. These LDAs corresponded to rarefied or necrotic parenchyma in which tumor cells remained, mainly in the perivascular spaces. One case exhibited diffuse tumor infiltration of periventricular structures which appeared to have normal density and no CE on the final pre-mortem CT.

Aged↗
PubMed1992

Magnetic resonance imaging and histopathology of cerebral gliomas.

The correlation of magnetic resonance imaging (MRI) with histopathological findings was analysed in 26 patients with untreated cerebral gliomas. In low-grade gliomas, T2-weighted images demonstrated relatively homogeneous high-intensity lesions involving both the grey and the white matter. In high-grade gliomas, especially grade IV, T2-weighted images demonstrated prominent heterogeneity in signal intensity, which consisted of a hyperintense "core", less hyperintense or normal intensity "rim" and surrounding finger-like areas of high intensity. Marked and irregular contrast enhancement was evident in all but one case of these high-grade gliomas in which gadolinium-DTPA was used. Histological examination revealed tumour cells extending as far as the borders of the high-intensity areas shown on T2-weighted images in both high- and low-grade gliomas, but in 5 of 8 low-grade and 4 of 18 high-grade gliomas, isolated tumour cells extended beyond the hyperintense areas shown on T2-weighted images.

Adolescent↗
PubMed1992

Phylogenetically different strains of a variant of coxsackievirus A 24 were repeatedly introduced but discontinued circulating in Japan.

Variations in the nucleotide sequence of 3 C proteinase of coxsackievirus A 24 variant (CA 24 v) were analyzed to define the route of transmission and spread of the virus which was introduced to Japan on three separate occasions, 1985-86, 1988, and 1989. The nucleotide sequences of isolates from the same year's outbreak in Japan were identical or closely related, while the isolates from different outbreaks were less closely related to one another than to those from other countries in the same year. All Japanese isolates from Okinawa and other prefectures in 1985 and 1986 were closely related to the Taiwan strains in those same years, indicating common-source outbreaks. Two 1988 isolates from Chiba Prefecture, Japan, were closely related to those from Singapore in 1987, China in 1988 and Hong Kong in 1988. All seven Japanese isolates from Chiba Prefecture in 1989 comprised a group together with the Taiwan and Singapore strains in 1988. The results indicate that CA 24 v was introduced into Japan on each occasion from the outside. Furthermore, in contrast to the explosive epidemics in Okinawa Prefecture in 1985 and 1986, the virus which was repeatedly introduced to other areas in Japan did not circulate endemically, and disappeared within a short time.

Base Sequence↗
PubMed1992

The complete nucleotide sequence of a variant of Coxsackievirus A24, an agent causing acute hemorrhagic conjunctivitis.

The complete nucleotide sequence was determined for the cDNAs that represent the RNA genome of the standard strain of a variant of coxsackievirus A24, the EH24/70, one of the agents causing acute hemorrhagic conjunctivitis. The genome is 7461 nucleotide long and is polyadenylated at the 3'-end terminus. Following a 750-nucleotide 5'-noncoding region, there was a long open reading frame of 6642 nucleotides, which serve to encode a viral polyprotein consisting of 2214 amino acids. Comparison of the deduced amino acid sequence of the polyprotein with those of known enteroviruses allowed us to predict the possible cleavage sites. The overall structure and the organization of the RNA genome is typical for an enterovirus. Based on the similarity of the nucleotide sequence of the 5' and 3' noncoding regions, together with the amino-acid sequence of the encoded proteins, EH24/70 appeared to be closely related to polioviruses and coxsackievirus A21.

Amino Acid Sequence↗
PubMed1992

Phylogenetic analysis of a coxsackievirus A24 variant: the most recent worldwide pandemic was caused by progenies of a virus prevalent around 1981.

Nucleotide substitutions in the viral-encoded proteinase 3C (3Cpro) region (549 nucleotides) of the RNA genome of a coxsackievirus A24 variant (CA24v), one of the agents causing acute hemorrhagic conjunctivitis (AHC), were studied using 32 isolates collected from the Eastern hemisphere in 1970-1989. Based on regression analysis of nucleotide differences among isolates, the nucleotide substitution rate of CA24v 3Cpro was estimated to be 3.7 x 10(-3)/nucleotide/year. A phylogenetic tree constructed by the modified unweighted pair group method using arithmetic averages (UPGMA) indicated that CA24v had evolved from a common ancestor which appeared in one focal place in November 1963 +/- 21 months, about 7 years before the first isolation of CA24v in Singapore. The tree also revealed that all the recent epidemic isolates in 1985-1989 including Asian and Ghanian strains diverged from each other after 1981. This finding is consistent with the evidence that AHC due to CA24v had been confined to Southeast Asia and the Indian subcontinent until 1985, then suddenly and explosively spread to other areas where no CA24v isolations had been reported.

Amino Acid Sequence↗
PubMed1992

Meningioma in a neonate: case report.

A 10-day-old female with a parasagittal meningioma presenting as a subcutaneous tumor is reported. Meningiomas within the 1st month of life are rare. The clinical and pathological characteristics of congenital meningioma are reviewed.

Female↗
PubMed1992

Uvula-nodulus and gravity direction (a study on vertical optokinetic-oculomotor functions).

Some characteristics of vertical optokinetic nystagmus and after-nystagmus, in particular, its up/down gain asymmetry, are known to be influenced by gravity direction, which is basically perceived by otolith organs. However, how such an information of gravity direction is processed within the central nervous system is not well understood, even though the role of cerebellar uvula and nodulus in vertical eye movements has been identified for some time. Accordingly, in this study, vertical optokinetic nystagmus and after-nystagmus were studied in squirrel monkeys both in the upright and side-lateral positions (different gravity direction to the head), before and after uvulonodulectomy. When the optokinetic stimulus was given, the slow phase eye velocity of optokinetic nystagmus was significantly higher in the side-lateral position than that obtained in the upright position. This difference disappeared after uvulonodulectomy. When the initial slow phase eye velocity of optokinetic after-nystagmus was compared, the one obtained in the side-lateral position was significantly higher than that acquired in the upright position. This difference also disappeared after the uvulonodular ablation. Thus, in this study of vertical optokinetic nystagmus and after-nystagmus, the role of uvula and nodulus in relaying the information of gravity direction was confirmed.

Animals↗
PubMed1992

Increased oxidized form of human serum albumin in patients with diabetes mellitus.

High-performance liquid chromatographic (HPLC) analysis of human serum albumin (HSA) on Asahipak GS-520H columns at neutral pH (6.87) showed a clear resolution of human mercaptalbumin (HMA) and nonmercaptalbumin (HNA), which are reduced and oxidized form of HSA, respectively. We studied the conversion of HMA to HNA (mercapt-nonmercapt conversion) as an index of oxidative change of the tissues and organs in 28 normal subjects and in a total of 47 patients with non-insulin dependent diabetes mellitus (NIDDM). Mean (+/- SD) values of the HMA fraction of HSA, f(HMA), [HMA/(HMA + HNA)], was significantly lower in NIDDM patients than in normal subjects (0.63 +/- 0.067 vs 0.75 +/- 0.028, P < 0.001). It was lower in poorly controlled NIDDM patients (0.63 +/- 0.058, n = 20) than in well controlled NIDDM patients (0.67 +/- 0.032, n = 9) (P < 0.05). Plasma glucose values sampled on occasions including overnight fasting and postprandial ones (r = -0.441, n = 47, P < 0.01), but not plasma glucose values sampled on overnight fasting (r = -0.345, n = 29) or postprandial (r = -0.467, n = 18) conditions and HbA1c (r = -0.211, n = 34), negatively correlated with the f(HMA) values, indicating that mercapt-nonmercapt conversion may not be due to cumulative hyperglycemia over a month, but due to short-term alteration in blood glucose level. The presence or absence of diabetic complications including nephropathy, retinopathy and neuropathy did not affect the f(HMA) values. In conclusion, decreased f(HMA) values in the diabetic patients suggested the presence of a rapidly altered oxidative change of albumin due to hyperglycemia.

Adult↗
PubMed1992

Catalytic wet-oxidation of human wastes produced in space: the effects of temperature elevation.

The filtrate of non-catalytical wet-oxidation sewage sludge was wet-oxidized again at 290 degrees C and 300 degrees C with a Ru-Rh catalyst. At each temperature, repeated batch tests were carried out. Both oxidation and denitrification efficiency of organic matter in the raw material were studied. In the 16 times batch tests at 300 degrees C, high and stable oxidation occurred. 98.0% of organic carbon in the raw material was oxidized and 98.3% of organic nitrogen was denitrified. At 290 degrees C, though high and stable denitrification occurred, oxidation did not occur highly and stably. A catalytic wet-oxidation system studied at 300 degrees C will be useful as a waste management system for a human life support system, where almost all food is resupplied from the earth. This system can prevent organic waste accumulation in the life support system.

Acetates↗