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Biomedical subjects

M Takeda

Publications and source records attributed to M Takeda.

At least 577 records · Page 32Linked to original sources
PubMed1994

Intranephron distribution of creatine content in rats.

Creatine is a high energy phosphate donor and play an important role not only in muscle contraction, but also in buffering intracellular energy storage. In this study, we have identified the creatine content in microdissected nephron segments with an ultramicromethod. All nephron segments tested contained creatine, however the distribution was not uniform. Glomerulus, cortical thick ascending limb of Henle's loop and distal tubule possessed comparatively large amounts of creatine when calculated as pM/micrograms tissue protein. When calculation was made as pM/mm tubule length, the first segment of the proximal tubule and the distal tubule were the highest. These results suggest the existence of heterogeneity in creatine content along the nephron as one of the biochemical characteristics in individual nephron segments.

Analysis of Variance↗
PubMed1994

Enzymatic characterization of cathepsin D in rabbit brains with experimental neurofibrillary changes.

Aluminium salt was injected intracerebrally into rabbits resulting in experimental neurofibrillary change (ENFC) formation as a model of Alzheimer neurofibrillary change. Cathepsin D was purified from the experimental and the control rabbit brains and the enzymatic properties were further investigated. The specific activity of cathepsin D in the tissue homogenate from the ENFC brains was 27% higher than that of the control, reflecting the induction of the enzyme by aluminium injection. The apparent Km values of the control and ENFC enzymes were calculated to be 26.3 microM, 29.3 microM, respectively, when assayed with bovine hemoglobin as substrate. The heat inactivation proceeded linearly with time for the control enzyme but biphasically for the ENFC enzyme, suggesting that less-reactive type of cathepsin D was induced by aluminium injection. Other properties such as molecular weight, optimum pH and amino acid composition were similar to each other.

Aluminum Chloride↗
PubMed1994

Lymphotoxin and TNF differ greatly in capacity to induce differentiation of human myeloblastic leukemia ML-1 cells.

We found that recombinant and natural lymphotoxin differ from TNF in that they only marginally induce differentiation of human myeloblastic leukemia ML-1 cells. Even at 1,000-fold concentrations, lymphotoxin was significantly less potent than TNF. Lymphotoxin competitively, but not completely, inhibited TNF-induced differentiation. Based on studies of the two types of TNF receptors (55 kDa and 75 kDa) using monoclonal antibodies, the binding activity of lymphotoxin to the receptors was less than 1/3 that of TNF, but lymphotoxin could bind to both TNF receptors. Both receptors were involved in induction of differentiation by TNF. However, lymphotoxin, differed from TNF; it seemed to be weak in sending signals for differentiation through the 75 kDa receptor.

Cell Differentiation↗
PubMed1994

[Virus-associated hemophagocytic syndrome with interstitial pneumonia in adults and a review of literature in Japan].

A 21-year-old man was admitted with fever, jaundice, abdominal pain and general fatigue. Other clinical manifestations revealed liver dysfunction, hepatosplenomegaly, pancytopenia and disseminated intravascular coagulation. Anti-EB virus (EA-DR-IgG) was initially elevated on admission and was decreased after that, furthermore anti EBNA was elevated in the late period of his clinical course, which indicated primary infection or secondary alteration of EBV immunity. Bone marrow examination revealed hemophagocytosis by mature histiocytes. Therefore, he was diagnosed as Virus-associated hemophagocytic syndrome (VAHS). An arterial blood gas analysis on admission showed hypoxemia and findings of interstitial pneumonia (IP) were distinctly observed on chest CT scan. Steroid therapy was then initiated and the patient responded very well. The clinical findings and laboratory data including IP, were improved. The 20 adult cases of VAHS in Japan were clinically studied and a review of the complication of VAHS with IP was also made.

Adult↗
PubMed1994

[Leiomyoma of the kidney: a case report].

A case of leiomyoma of the kidney is reported. A 57-year-old man with the chief complaint of right back pain was consulted to our hospital. Abdominal computed tomography (CT) demonstrated a right renal tumor. Right renal angiography revealed a hypovascular lesion. Under the diagnosis of right renal tumor, right radical nephrectomy was performed. Gross evaluation revealed a well encapsulated solid mass. The tumor was 48 x 43 x 42 mm in diameter and a hemorrhagic region was present. Microscopically, the tumor was composed of interlacing bundles of spindle cells. Diagnosis was leiomyoma of the kidney. We reviewed 42 cases of renal leiomyoma reported in Japanese literature.

Humans↗
PubMed1994

Divergent expression of EtA and EtB receptors in response to cyclosporine in mesangial cells.

We examined the effects of cyclosporine (Cy) on preproendothelin-1 (prepro Et-1) and both Et receptors, A-type (EtA) and B-type (EtB), in rat glomerular mesangial cells. Cy at 10(-5) mol/L, the concentration relevant to tissue levels in vivo, increased mRNA for prepro Et-1 after both 1 and 3 hours to 183 +/- 14% (n = 8) and 147 +/- 12% (n = 9) of levels seen in control cells. A similar pattern was observed at a lower dose of Cy (10(-6) mol/L, the concentration relevant to plasma levels in vivo): at 1 hour, expression increased to 146 +/- 15% (n = 5); at 3 hours, expression was 159 +/- 25% (n = 8). Concomitant with these changes in expression of prepro Et-1 mRNA, the Et-1 protein nearly doubled at 3 hours. Both EtA and EtB mRNA were expressed in unstimulated mesangial cells and were affected differently by Cy. Little change was observed in the EtA mRNA. In contrast, EtB mRNA increased with Cy (10(-5) mol/L) up to 129 +/- 8% (n = 6) at 1 hour and 265 +/- 62% (n = 3) at 3 hours. A similar effect was seen with the lower dose of Cy: EtB expression increased to 129 +/- 9% (n = 6) of control value at 1 hour and 253 +/- 74% (n = 4) at 3 hours. These results indicate that Cy enhances expression of mRNA for prepro Et-1 and production of mature Et-1 by glomerular mesangial cells. Further, Cy has differential effects on EtA and EtB, affecting EtA minimally while markedly increasing the expression of EtB. These results constitute the first demonstration that Et receptor subtypes are modulated in a pathophysiological setting. The divergent modulation of EtA and EtB raises the possibility that there are differences in contribution of each of the receptor subtypes to pathophysiological mechanisms of Cy toxicity.

Animals↗
PubMed1994

Laparoscopic adrenalectomy for primary aldosteronism: report of initial ten cases.

BACKGROUND: Although laparoscopic technique has become popular in the surgical field, the value of laparoscopy in the removal of adrenal gland is unknown. The objective of this study was to examine the feasibility of laparoscopic adrenalectomy. METHODS: Between January 17, 1992, and March 16, 1993, 10 patients (four men, six women; mean, 48.2 years of age) with primary aldosteronism underwent laparoscopic adrenalectomy (seven of left adrenal gland and three of right adrenal gland) with almost the same devices as laparoscopic cholecystectomy. RESULTS: Adrenal tumors were successfully removed with adjacent normal adrenal gland in every patient. The operative time ranged from 165 to 572 minutes (mean, 295 minutes), and the operative bleeding ranged from 50 to 920 ml (mean, 270.5 ml) without requiring blood transfusion. Only one patient required open hemostasis because of uncontrollable bleeding complicated by dislocation of vascular clip in spite of successful laparoscopic removal of adrenal tumor. There was no major complication except for this case. CONCLUSIONS: Laparoscopic adrenalectomy is a relatively safe, alternative operative method for primary aldosteronism, but application of this technique to other types of adrenal lesions remains to be studied.

Adrenalectomy↗
PubMed1993

Benzylideneascorbate induces apoptosis in L929 tumor cells.

Sodium 5,6-benzylideneascorbate (SBA), which is known to be an antitumor substance, was found to induce apoptotic cell death of L929 tumor cells directly in a concentration- and time-dependent manner. The dying cells exhibited cell shrinkage, disappearance of cell surface microvilli, chromatin condensation and DNA fragmentation into nucleosomal oligomers characteristic of apoptosis. These results indicate a possible mechanism by which SBA induces tumor regression in vivo.

Animals↗
PubMed1993

Basal cells in the mouse olfactory epithelium during development: immunohistochemical and electron-microscopic studies.

The basal region in the developing olfactory epithelium of mice was investigated by double immunostaining using anti-keratin (MA903) and anti-bromodeoxyuridine antibodies. Basal cells proper, which are MA903 positive, and globose basal cells, which are MA903 negative, were differentiated in the basal region on embryonic day 18 to postnatal day 1. At this stage, BrdU-labeling was found more in the glubose basal cells than in the basal cells proper. The labeled globose basal cells increased in number and reached the maximum on postnatal day 3, and decreased in number on postnatal day 14. The labeled basal cells proper was concentrated near the border with the respiratory epithelium on postnatal day 1, but they were found in small numbers in other regions of olfactory epithelium during later stages of development. Active division of globose basal cells accompanied the 1.5-fold increase in the thickness of the olfactory epithelium, which is caused by the increase in the number of olfactory cells, during development. It is suggested that during late embryonic and postnatal days olfactory cells originate from globose basal cells, not from basal cells proper. The division of basal cells proper may contribute to an 8-fold increase in the surface area of the olfactory epithelium during development.

Animals↗
PubMed1993

Brachytherapy for stage I & II oral tongue cancer: an analysis of past cases focusing on control and complications.

An analysis of the therapy used for 370 tongue cancer patients has been made, said patients having been treated by interstitial irradiation alone or by combined external irradiation and brachytherapy (Stage I:90 cases, IIa: 196 cases; and IIb: 84 cases). The neck was followed by close follow-up (304 cases), treated by elective neck irradiation (56 cases), or underwent operation at the time of local recurrence (10 cases). The results have shown that the 5-year survivals for Stages I, IIa, and IIb were 84%, 78%, and 72%, respectively. further, the 5-year primary control was 85% for tumors of the superficial type, 79% for tumors of the exophytic type, and 45% for tumors of the infiltrative type (p < 0.004). In non-electively irradiated patients, a neck metastasis occurred in 31% in Stage I, 41% in Stage IIa, and 51% in Stage IIb. Finally, 110 patients incurred radiation-induced complications (110/291 = 38%) and 11 patients (11/291 = 4%) required a surgical procedure. Brachytherapy for tongue cancer achieved results that are comparable with surgery. The analysis also revealed that the introduction of computer dosimetry and the use of a spacer (a dental guard) in brachytherapy have achieved superior results in the management of a tongue cancer.

Adult↗
PubMed1993

Acceleration of bovine neurofilament L assembly by deprivation of acidic tail domain.

Functions of the tail region of neurofilament L have, to date, not been clearly elucidated. Bovine neurofilament L was cleaved into tail-less neurofilament L (50 kDa) and a tail fragment (19 kDa), by thrombin. Tail-less neurofilament L was deficit of the highly acidic domain of the tail region (approximately 77% of the entire region). Assembly of tail-less neurofilament L. was observed to be accelerated by both fluorometric and centrifugal measurements, compared with intact neurofilament L. The critical concentration of tail-less neurofilament L, which constitutes the constant unassembled pool, was approximately 0.25-times lower than that of neurofilament L. Under physiological conditions, tail-less neurofilament L formed a ribbon-like structure, whereas tail-less neurofilament L could form 10-nm filaments in an extremely low ionic-strength buffer in the presence of 1 mM MgCl2. An affinity-purified antibody directed against the tail fragment also accelerated neurofilament L assembly. The tail fragment neither coassembled with neurofilament L nor affect neurofilament L assembly. The acidic domain of the tail region may regulate neurofilament assembly and may be involved in 10-nm filament formation under physiological conditions.

Amino Acid Sequence↗
PubMed1993

Pharmacokinetics of anticholinergic drugs and brain muscarinic receptor alterations in streptozotocin diabetic rats.

We studied the effects of experimental diabetes on the pharmacokinetics of biperiden (BP) and scopolamine (SP) and brain muscarinic receptor alterations in rats after the injection of streptozotocin (STZ) (60 mg kg-1 i.v.). The serum levels of BP and SP differed significantly between the rats 14 weeks after the STZ treatment and age-matched control rats. The values of total body clearance (CLtot) of BP and SP were significantly increased by STZ treatment. The values of volume of distribution (Vdss) of SP were slightly increased in the STZ-treated rats, although Vdss of BP was decreased. Because of the high lipophilicity of BP, Vdss of BP may be decreased due to the reduced fat tissue volume caused by STZ treatment. The density of the muscarinic receptors in whole brain was measured by a radioligand receptor binding assay using [3H]-quinuclidinyl-benzylate ([3H]-QNB). The density in the diabetic rats two weeks after the STZ treatment was significantly decreased compared to age-matched control rats. However in the diabetic rats 14 weeks after the STZ treatment, there was no difference in the density of muscarinic receptors. The IC50 of muscarinic antagonist for the binding of [3H]-QNB to the receptor did not change on STZ treatment. Modulation of the receptor following repeated anticholinergic drug exposure was studied. In control rats, the number of muscarinic receptors in the brain increased by 6.9% on chronic treatment with BP for two weeks. When diabetic rats were treated with BP and SP, the number of muscarinic receptors in the brain increased by 9.6% and 33.8%, respectively.

Animals↗