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Biomedical subjects

R Tanaka

Publications and source records attributed to R Tanaka.

At least 433 records · Page 24Linked to original sources
PubMed1993

Rate of stratum corneum formation in the perinatal rat.

During late gestation, the fetal rat exhibits marked hyperplasia of the interfollicular epidermis and accelerated cornification in preparation for birth. In this study, we utilized simple morphometric techniques to provide quantitative estimates of the rate of stratum corneum (SC) formation during the perinatal period. Cryostat sections of dorsal epidermis from rat pups between -48 and +72 h of age were expanded under alkaline conditions and the number of corneocyte interfaces counted from photomicrographs. This method yielded the following regression lines: prenatal, y = 0.19x + 13.07, r = 0.93; postnatal, y = 0.13x + 13.00, r = 0.93, where y = number of SC layers and x = age in hours. Lack of desquamation was assured by the postnatal persistence of the granular periderm. Adhesive stripping of the epidermis followed by phase-contrast microscopy revealed intact monolayer sheets of SC. Quantitation using a computerized image analysis system gave an average corneocyte surface area in the newborn rat of 1908 +/- 36 mu 2 (mean +/- SEM). Treatment of neonatal rats with epidermal growth factor (500 ng/g BW) increased the number of SC layers over the first 24 h of life (p < 0.05) and resulted in marked hyperkeratosis by one week of age. These results allow the following conclusions: 1) in the prenatal rat, SC forms at a rate of one layer every 5 h; 2) postnatally, SC formation slows to one layer every 8 h; 3) to support normal corneum synthesis at birth, dorsal keratinocytes must enter transition at a rate of approximately 3 cells/second/cm2 of body surface; and 4) treatment with exogenous EGF augments the rate of terminal differentiation of perinatal rat epidermis.

Animals↗
PubMed1993

The effects of transgalactosylated oligosaccharides on gut flora metabolism in rats associated with a human faecal microflora.

The effect on various caecal bacteria and their metabolic activities of feeding diet containing transgalactosylated oligosaccharides (TOS) with or without Bifidobacterium breve (administered in the drinking water) was investigated in rats colonized with a human faecal microflora. TOS (5% w/w in diet) or TOS plus B. breve, given for 4 weeks, induced increases in caecal concentration of total anaerobic bacteria, lactobacilli and bifidobacteria, and decreases in numbers of enterobacteria. Caecal pH was significantly reduced by feeding TOS, as were the activities of beta-glucuronidase and nitrate reductase. In contrast, beta-glucosidase activity was increased in TOS-fed rats. Dietary TOS was also associated with decreased conversion, by caecal contents, of the dietary carcinogen 2-amino-3-methyl-3H-imidazo[4,5-f] quinoline (IQ) to its genotoxic 7-hydroxy derivative.

Animals↗
PubMed1993

Mechanisms of alpha-Sialosyl cholesterol action to suppress both cyclic AMP production and DNA synthesis of rat glial cells.

alpha-Sialosyl cholesterol (alpha-SC) that elicited morphological differentiation of rat astrocytes not only lowered intracellular cyclic AMP (cAMP) levels but also inhibited cAMP production induced by either alpha-isoproterenol, cholera toxin, or forskolin. The targets of alpha-SC in the cAMP production system of rat astrocytes were investigated to understand the mechanism of the alpha-SC action on cAMP production. cAMP production evoked by alpha-isoproterenol (1 microM) was entirely canceled by beta blockers such as propranolol and timolol (1 microM), but not by alpha-SC. Concentrations of alpha-SC greater than 15 microM were required for 50% inhibition of the activation by a beta agonist. Although alpha-SC inhibited in a dose-dependent manner the activities of membrane-associated adenylate cyclase that had been stimulated by either GTP gamma S of forskolin, alpha-SC inhibited neither GTP-binding activities nor GTPase activities of the membrane-associated G proteins. These findings suggest that alpha-SC suppresses adenylate cyclase directly, but not beta receptors or G proteins, and that it promotes the morphological differentiation of rat astrocytes through a mechanism regulating directly the cytoskeletal organization, regardless of intracellular cAMP level. alpha-SC (30 microM) suppressed 40% of DNA synthesis in the cell-free system, which contained the cytosolic extracts and the nucleus fraction prepared from rat astrocytoma C6 cells. Approximately 25% of alpha-SC incorporated in the astrocyte cytoplasm was transferred to the nuclei by 10 min after the addition.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Analysis of ploidy and sexual characteristics of natural isolates of Cryptococcus neoformans.

We report here an extensive examination of the ploidy of a basidiomycetous yeast. The ploidy of 34 strains of Cryptococcus neoformans var. neoformans, isolated mostly from Japanese patients, was determined by means of quantitative fluorescence microscopy after DNA staining with propidium iodide. The sexual characteristics of the strains including the two tester strains were as follows. Twenty-four strains were of the heterothallic alpha type, 1 was of the heterothallic a type, and 2 were self fertile; the remaining 7 showed no sexual response. The following strains were found to be haploid: the heterothallic a strain, 20 of the 24 heterothallic alpha strains, and 3 of the 7 asexual strains. Thus, the C. neoformans strains were mostly haploid, as the sexual response of this organism suggests. Both of the self-fertile strains and four of the seven asexual strains were diploid. Unexpectedly, 4 of the 24 heterothallic alpha strains were diploid.

Cryptococcus neoformans↗
PubMed1993

Regional cerebral blood flow measured with N-isopropyl-p-[123I]iodoamphetamine and its redistribution in ischemic cerebrovascular disease.

BACKGROUND AND PURPOSE: The relation between the redistribution phenomenon and regional cerebral blood flow and its clinical significance were investigated in stroke patients. METHODS: Single-photon emission computed tomography studies using N-isopropyl-p-[123I]iodoamphetamine were performed on 16 patients (26 to 77 years old) with chronic infarction and 10 age-matched normal control subjects. Regional cerebral blood flow was quantitatively measured by a microsphere model, and the redistribution on delayed images was analyzed in ischemic lesions. RESULTS: Supratentorial mean cerebral blood flow and the ratio of gray matter to white matter in normal subjects were 52.7 +/- 5.0 mL/100 g per minute and 2.34, respectively. Low-activity areas of ischemic lesions on early images were classified into two abnormal zones, an infarct area and a peri-infarct area. These regions were characterized by regional blood flow averaging 9 to 20 mL/100 g per minute and 22 to 41 mL/100 g per minute, respectively. Redistribution, which was minimally present in the infarct area, was markedly enhanced in the peri-infarct area. After bypass surgery, we observed a significant increase of blood flow (+22%) in the peri-infarct area. CONCLUSIONS: The data indicate that the redistribution phenomenon depends on the maintenance of a minimal blood flow that would sustain cellular function and that this phenomenon is useful to evaluate bypass surgery in patients with chronic infarction.

Adult↗
PubMed1993

Isolation and characterization of seven lyso platelet-activating factors and two lyso phosphatidylcholines from the crude drug "suitetsu" (the leech, Hirudo nipponica).

Nine lyso glycerophospholipids were isolated in the pure state from the crude drug "Suitetsu", which is the dried body of the leech, Hirudo nipponica (Hirudidae). They were identified as 1-O-hexadecyl-(1), 1-O-octadecyl-(2), 1-O-tetradecyl-(3), 1-O-9-cis-hexadecenyl-(4), 1-O-hexadecanoyl-(5), 1-O-pentadecyl-(6), 1-O-15-methylhexadecyl-(7), 1-O-octadecanoyl-(8) and 1-O-heptadecyl-sn-glycero-3-phosphocholine (9). Two of them (5 and 8) are lysophosphatidylcholines and the other seven are lyso platelet-activating factors. One of them has an alkenyl carbon chain.

Animals↗
PubMed1993

Studies on the constituents of Aster scaber Thunb. IV. Structures of four new echinocystic acid glycosides isolated from the herb.

Four new echinocystic acid 3,28-O-bisdesmosides, scaberosides Ha, Hb1, Hb2 and Hc1, were isolated as their methyl esters from the ground part of Aster scaber THUNB. (Compositae) along with foetidissimoside A and scaberoside A2, and their structures were determined based on spectral and chemical evidence. These glycosides have a common prosapogenin structure, echinocystic acid 3-O-glucopyranosiduronic acid, and differ in the structures of the 28-O-linked sugar moieties. Scaberoside Ha1 is a 28-[O-alpha-L-rhamnopyranosyl-(1-->2)-[O-alpha-L-rhamnopyranosyl-(1-->3) ] - beta-D-xylopyranosyl] ester, Hb1, a 28-[O-beta-D-xylopyranosyl-(1-->4)-O-alpha-L-rhamnopyranosyl-(1-->2)- [O-alpha-L-rhamnopyranosyl-(1-->3)]-beta-D-xylopyranosyl] ester, Hb2, a 28-[O-beta-D-xylopyranosyl-(1-->3)-O-beta-D-xylopyranosyl-(1-->4)-O-alph a-L- rhamnopyranosyl-(1-->2)-[O-alpha-L-rhamnopyranosyl-(1-->3)]-beta-D- xylopyranosyl] ester, and Hc1, a 28-[O-beta-D-xylopyranosyl-(1-->3)-O-beta-D-xylopyranosyl-(1-->3)-[O-bet a- D-xylopyranosyl-(1-->4)]-O-alpha-L-rhamnopyranosyl-(1-->2)-[O-alpha-L- rhamnopyranosyl-(1-->3)]-beta-D-xylopyranosyl] ester of the prosapogenin.

Carbohydrate Sequence↗
PubMed1993

A patient with primary hyperparathyroidism associated with osteomalacia: markedly increased serum levels of intact PTH and 1,25-dihydroxyvitamin D with normo- and hypercalcemia.

A 65-year-old female patient was admitted with complaining chiefly of lower back pains and arthralgia in the bilateral knee joints of 10-years duration. The serum calcium concentration was normal or only slightly increased, whereas the serum intact PTH and 1,25-dihydroxyvitamin D concentrations were substantially increased. Serum phosphate and 25-hydroxyvitamin D concentrations were decreased. Renal function was normal. Serum alkaline phosphatase activity, the osteocalcin concentration and urinary hydroxyproline excretion were markedly increased. Bone X-ray examination showed severe osteopenia and bone biopsy revealed hyperosteoidosis without tetracycline deposition, consistent with osteomalacia. A parathyroid adenoma was demonstrated by echography and CT-scan. Surgical exploration of the neck revealed a chief cell adenoma behind the right upper pole of the thyroid gland. After parathyroidectomy, all the abnormal biochemical data gradually normalized and the patient has been doing well without any symptoms for the last 13 months. These clinical data suggest that osteomalacia of the patient was probably induced by hypophosphatemia of prolonged duration. When hypercalcemia is not evident in a patient with primary hyperparathyroidism, in whom serum alkaline phosphatase and intact PTH levels are inappropriately increased, osteomalacia should be taken into consideration.

Adenoma↗
PubMed1993

[Reverse mutation test of trandolapril (RU44570) with bacteria].

Mutagenicity of trandolapril (RU44570) was evaluated by the reverse mutation test with bacteria (test strains used: Salmonella typhimurium TA100, TA98, TA1535, TA1537 and Escherichia coli WP2uvrA). The test was conducted by the preincubation method without metabolic activation (in the absence of S9 mix) and with metabolic activation (in the presence of S9 mix). The number of revertant colonies in the bacterial strains did not exceed twice that obtained in the solvent control either in the presence or absence of S9 mix. There was no dose-dependent increase in the number of revertant colonies observed. Based on the above results, it is concluded that RU44570 has no mutagenicity (gene mutation) under the conditions of the present study.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1993

Subclinical carpal tunnel syndrome in acromegaly.

Median nerve conduction was studied in 16 acromegalic patients with asymptomatic carpal tunnel syndrome (CTS) to examine the incidence of subclinical CTS. Thirteen patients (81%) and 23 hands (72%) demonstrated subclinical CTS, 10 bilaterally and three unilaterally in the dominant hand. The incidence reflects the greater sensitivity of the inching method for detecting focal conduction abnormalities. Two of three patients without subclinical CTS showed normal plasma somatomedin-C concentration despite growth hormone hypersecretion. Following adenomectomy, nerve conduction normalized in only six hands (26%). The postoperative persistence of the conduction delay implies that irreversible narrowing of the carpal tunnel rather than reversible soft tissue edema is the principal cause of CTS associated with acromegaly.

Acromegaly↗
PubMed1993

Effects of ACNU and cranial irradiation on the mouse immune system.

The effects of ACNU and cranial irradiation on the immune system were studied in three groups of 90 mice: Group A, intraperitoneal injection of ACNU (30 mg/kg); Group B, single exposure of 10 Gy to the head; and Group C, intraperitoneal injection of ACNU (30 mg/kg) and single exposure of 10 Gy to the head. Peripheral white blood cell counts, spleen cell subsets, natural killer (NK) cell activity, lymphocyte blastogenesis, and production of interferon (IFN)-gamma were analyzed once a week for 6 weeks after treatment. In Group A, NK cell activity decreased between weeks 4-5, concanavalin A blastogenesis decreased during weeks 1-5, and the levels of L3T4 (CD4) and Lyt2 cells (CD8) and IFN-gamma production decreased during weeks 2-5. However, all tested parameters returned to the normal range at 6 weeks. In Group B, all parameters except for the L3T4 cell level and the IFN-gamma production decreased during week 1, and returned to the normal range thereafter. The concentration of L3T4 cells decreased during week 2 and between weeks 5-6. The IFN-gamma production increased during week 1, decreased during week 2, and returned to the normal range thereafter. In Group C, the suppressive effects were severe and continued for a longer period than in either Group A or B. Concanavalin A blastogenesis, L3T4 cell concentration, and IFN-gamma production were still suppressed after 6 weeks. Therefore, intensive radiochemotherapy for brain tumor may suppress the immunological function.

Animals↗
PubMed1993

Effects of irradiation on cytokine production in glioma cell lines.

The effects of irradiation on cytokine production in glioma cell lines, NP1, NP2 and NP3, were studied. Culture supernatants were collected after 6, 24, 48 or 72 hours and the concentrations of interleukin (IL)-6 and IL-8 measured by enzyme-linked immunosorbent assay. Spontaneous and IL-1 beta-stimulated productions were analyzed. Some cells were given a single dose of Lineac irradiation (10 or 20 Gy). Production of IL-6 (with or without IL-1 beta stimulation) increased gradually to a maximum after 72 hours, more in the 20 Gy-irradiated cells than 10 Gy cells (p < 0.01). Production of IL-8 increased gradually to a maximum after 48 or 72 hours. Spontaneous production of IL-8 increased more in 20 Gy-irradiated cells than 10 Gy cells after 6 and 24 hours (p < 0.01), but increased more in 10 Gy cells than 20 Gy cells after 48 and 72 hours (p < 0.01). The production of IL-8 stimulated by IL-1 beta increased more in 10 Gy cells than 20 Gy cells 24 hours later (p < 0.01). IL-6 and IL-8 production differed in the response to irradiation. Our data suggest that bidirectional communication between the immune system and glioma cells changes after radiotherapy.

Glioma↗
PubMed1993

Effects of irradiation on the expression of the adhesion molecules (NCAM, ICAM-1) by glioma cell lines.

The expression of the intercellular adhesion molecule-1 (ICAM-1) and neural cell adhesion molecule (NCAM) by glioma cell lines was investigated. The effects of interferon (IFN)-gamma or irradiation on the expression was also assessed. Two glioma cell lines showed more than 75% NCAM-positive cells. After treatment with IFN-gamma or irradiation, another three cell lines were induced to show more than 50% positive cells. Three glioma cell lines showed more than 50% ICAM-1-positive cells. After treatment with IFN-gamma, another two cell lines were induced to show more than 50% positive cells. After treatment with irradiation, one more cell line was induced to show more than 50% positive cells. ICAM-1 and NCAM expression by glioma cell lines is susceptible to modulation by IFN-gamma or irradiation.

Cell Adhesion Molecules↗
PubMed1993

Neuropsychological outcome and social recovery of head-injured patients.

The Wechsler Adult Intelligence Scale and Yatabe-Guilford personality test were administered to 123 patients hospitalized for head injury who had made a relatively good recovery. Intelligence quotient (IQ) was correlated with clinical condition based on the Glasgow Coma Scale and duration of coma. More severely injured patients tended to show a greater decline in IQ. The type of lesion, as described by computed tomography, was also an important factor in predicting the outcome of intellectual function. The mean IQ of patients with diffuse injury, such as diffuse axonal injury and diffuse brain swelling, and intracerebral hematoma, was significantly lower than that of the control subjects, especially performance IQ (PIQ). Several patients demonstrated improved IQ level during the initial year. In particular, PIQ improved more than verbal IQ. The difference between the IQ of patients achieving social recovery and not was significant (p < 0.001). Causes of difficulty in returning to previous work were decreased IQ and personality change, such as lack of cooperativeness. Neuropsychological evaluation is important in predicting social recovery and selecting necessary neuropsychological rehabilitation.

Adolescent↗
PubMed1993

Epizootiological study of hantavirus infection among Rattus norvegicus in Tokyo Bay area, Japan.

The prevalence of antibodies against hantavirus in 413 rats (Rattus norvegicus) captured in eight regions of the Tokyo Bay area from 1983 to 1992 were examined by the indirect fluorescent antibody test. Antibody-positive rats were found in Tokyo Port in 1983 (34.8%), 1984 (25.9%), 1985 (22.0%) and 1986 (15.6%), in Kasai Seaside Park in 1989 (3.2%) and 1990 (4.2%) and in Chiba Port in 1990 (6.7%). In Tokyo Port, antibody-positive rats were found in any season in 1984 and 1985, and seroprevalences among two age groups, i. e., less than six months and six or more months of age were 18.1% and 28.4%, respectively. Three virus strains were isolated from rats captured on reclaimed land No. 13 in Tokyo Port in 1985 and named TQR-23, TQR-48 and TQR-50. These strains were antigenically identical with other rat strains, e. g., strain SR-11 and TR-352 but were discriminated from 76-118 strain by the neutralization test. Until 1990, persistence of hantavirus among rats inhabiting the Tokyo Bay area was demonstrated and hantavirus may be continuously prevalent in rats in this area.

Animals↗
PubMed1993

[Neuropsychological outcome of head injury in children].

Wechsler Intelligence Scale for Children-Revised (WISC-R) and Yatabe-Guilford personality test were administered to 31 children who had been hospitalized for head injury and made a GR or MD by the Glasgow Outcome Scale (GOS). The type of lesion, as defined by CT scan categories, was an important factor to prognosticate the outcome of intellectual function. The IQ, especially performance IQ, of acute subdural hematoma (EDH) or severe diffuse brain injury (DBI) was lower than that caused by other types of lesion. Several children demonstrated improvement in IQ level during the initial year. The difference between the IQ of the children who could return to previous school life and that of the children who could not was significant. One of the causes of difficulty in returning to previous school life is decreasing IQ and personality change such as social disadaptability. Neuropsychological evaluation is important in predicting school recovery and deciding proper neuropsychological rehabilitation.

Child↗
PubMed1992

Calpain may produce a Ca(2+)-independent form of kinase C in long-term potentiation.

Both an enhancement of Ca(2+)-independent kinase activity in the supernatant fraction and enhanced breakdown of type beta kinase C (PKC-beta) were observed in the hippocampus after induction of tetanus-induced long-term potentiation (LTP) in the hippocampal CA1 region of rat. The enhanced activity was inhibited by the PKC-specific inhibitor, PKC19-36. Both phenomena were also observed simultaneously in the in vitro model system in which hippocampal homogenate was treated with CaCl2, and both enhancements were inhibited by the addition of calpain inhibitors, leupeptin and benzyloxycarbonyl-Leu-Met-H. The results suggest that Ca(2+)-independent kinase activity enhanced in the supernatant fraction during LTP derives from the catalytic fragment of PKC-beta released by calpain.

Animals↗