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Biomedical subjects

A Kato

Publications and source records attributed to A Kato.

At least 469 records · Page 26Linked to original sources
PubMed1993

Topographic relationship between anteromedial thalamic nucleus neurons and their cortical terminal fields in the rat.

The present study has examined the topographic relationship between cells in the anteromedial thalamic nucleus (AM) and their cortical terminal fields, with retrograde transport of Fluoro Gold in the rat. Projections to the frontal area 2 originate from the ventrolateral part of the AM and the entire interanteromedial nucleus (IAM). Projections to the anterior cingulate area originate from the peripheral part of the rostral AM and the entire IAM. Fibers to the rostral retrosplenial area arise from the caudodorsal part of the AM, whereas those to the caudal retrosplenial area arise from the rostralmost and the rostrodorsomedial parts. Fibers to the rostral area 29D originate from the rostrocentral part of the AM, whereas those to the caudal area 29D originate from the rostroventrolateral and the ventromedial parts. Projections to the medial half of the entorhinal area originate from the rostrodorsomedial part of the AM. In contrast, projections to the lateral half of the entorhinal area originate from the IAM and the central part of the AM. The results show a complex topographic relationship between cells of origin of the AM and their cortical terminal fields, suggesting complex functional roles played by the AM in learning behavior such as discriminative avoidance behavior.

Animals↗
PubMed1993

Effects of agarwood extracts on the central nervous system in mice.

Agarwood (Jinkoh in Japanese) is an Oriental medicine for use as a sedative. Neuropharmacological studies have been conducted with the extracts of petroleum ether, benzene, chloroform, and water from agarwood (Aquilaria sp.; probably Aquilaria malaccensis Benth.) in mice. The benzene extract showed a reducing effect in spontaneous motility, a prolonging effect on hexobarbiturate-induced sleeping time, a hypothermic effect in terms of rectal temperature, and a suppressive effect on acetic acid-writhing by oral administration. Fr. 1 of the three fractions which were obtained from the benzene extract by column chromatography was found to produce more positive effects on these neuropharmacological tests than the original benzene extract. These facts suggest that the benzene extractable compounds of agarwood possess potent central nervous system depressant activities.

Animals↗
PubMed1993

Mitogenic activities in African traditional herbal medicines.

Mitogenic activities in African traditional herbal medicines were examined using protein fractions obtained from their extracts by precipitation with ammonium sulfate. Potent mitogenic activities for human and mouse lymphocytes were found in the three plants: Croton macrostachyus, Croton megalocarpus (Euphorbiaceae), and Phytolacca dodecandra (Phytolaccaceae). All the gel chromatographic patterns of these protein fractions progressed toward the smaller molecule site with pronase treatment, while their mitogenic activities decreased significantly. Protein fractions from these three plants induced mitogenesis both in human and mouse isolated T cells, but not in lymphocytes from athymic nude mice. By testing further fractionated protein fractions with gel filtration chromatography, it was found that all three plants contained several mitogens having different molecule sizes.

Africa↗
PubMed1993

The greater vulnerability of bile duct cells to reoxygenation injury than to anoxia. Implications for the pathogenesis of biliary strictures after liver transplantation.

The occurrence of biliary strictures in allografts following liver transplantation correlates with the duration of preservation time. The correlation between preservation time and biliary strictures suggests that anoxic or reperfusion injury of the bile duct epithelium causes stricture formation. However, the relative susceptibility of bile duct cells to anoxic or reoxygenation injury is unknown. Our aims were to determine the vulnerability of rat liver bile duct cells to anoxic and reoxygenation injury and to compare the results with hepatocytes. During anoxia, bile duct epithelial cells were significantly more resistant to cell killing than hepatocytes. Rates of cellular proteolysis were also 2.5-fold lower in bile duct cells than in hepatocytes during anoxia. In contrast to anoxia, reoxygenation of anoxic cells increased cell killing of bile duct cells but improved viability of hepatocytes. The rate of toxic oxygen species formation by bile duct cells was 5-fold greater than in hepatocytes during reoxygenation. In addition, basal levels of glutathione are lower in bile duct cells than in hepatocytes. These data suggest that bile duct cells are more susceptible to reoxygenation injury than to anoxia. These studies support the hypothesis that reoxygenation injury during liver preservation leads to bile duct injury during liver transplantation.

Animals↗
PubMed1993

Establishment of a human small cell lung carcinoma cell line carrying amplification of c-myc gene and chromosomal translocation of t(3p;6p) and t(12q;17p).

A transplantable tumor and an in vitro culture cell line (GK-T3) were established from metastatic liver tissue of human small cell lung carcinoma (SCLC). Southern blot analysis revealed about 30-fold amplification of c-myc gene in the tumor cells in liver, xenografts, and in vitro cell line. The degree of c-myc amplification was essentially conserved through serial passages in nude mice and cultivation in vitro. The level of c-myc mRNA was significantly increased in these cells. Cytogenetically, numerical and complex structural abnormalities were observed in GK-T3 cells, including t(3p;6p), t(12q;17p), two homogeneously staining regions (hsrs) and several double minutes (dmins). These results suggest that activation of c-myc gene and alteration of gene(s) around these chromosomal breakpoints may play a role in tumorigenesis of GK-T3 SCLC.

Aged↗
PubMed1993

Lysosome labilizers potentiate the antitumor effects of tumor necrosis factor-alpha.

Enhancement of in vitro cytotoxic activity of tumor necrosis factor-alpha (TNF-alpha) was observed in combination with lysosome labilizers, particularly with urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA) and lipoprotein lipase (LPL). The concentration of TNF-alpha resulting in 50% cytotoxicity to L929 cells was only 20-30% of the value for TNF-alpha alone, when used in combination with a nontoxic dose of u-PA, t-PA or LPL. Furthermore, combined intravenous (i.v.) administration of TNF-alpha (3.5 x 10(5) U/mouse) and u-PA (300 IU/mouse) markedly increased the in vivo antitumor activity of TNF-alpha to Meth A tumors transplanted into BALB/c mice; the tumor weight in co-administered mice was about 40% of that in mice given TNF-alpha alone on day 6. The combination therapy of TNF-alpha (7.0 x 10(4) U/mouse, i.v.) and u-PA (300 IU/mouse, i.v.) was also effective for L929 tumors in Crj:CD-1(1CR)-nu nude mice compared with the conventional therapy with TNF-alpha alone. These results suggest that the combination of TNF-alpha and lysosome labilizers is a promising antitumor therapeutic regimen with clinical potential.

Animals↗
PubMed1993

Serum concentration and cardiovascular effects of salbutamol after oral and rectal administration in healthy volunteers.

In order to evaluate rectal administration of salbutamol (SB), five healthy volunteers were dosed orally and rectally with racemic SB (0.1 mg/kg) solution. Compared with the oral SB, the rectal SB gave significantly higher serum SB concentration immediately after dosing but slightly lower levels in the elimination phase. The Cmax following rectal administration was 17.9 ng/ml (17.0 ng/ml for oral administration), the tmax 0.67 h (1.5 h for oral administration) and the AUC 98.2 ng/ml/h (100 ng/ml/h for oral administration). Heart rate also rose more rapidly to a maximum of 70% above baseline values after rectal dosing. The rate continued to be twice larger than after oral dosing for up to 5 h. The concentration versus response curves indicated that rectal SB was more effective than oral SB at increasing heart rate at the same SB concentration in serum. A plausible explanation for this phenomenon might be a difference in the stereo-selective first-pass metabolism of the two enantiomers. Therefore, the rectal dose of SB administered as a suppository for prophylactic treatment of asthma should be lower than that used orally.

Administration, Oral↗
PubMed1993

Topology and subcellular localization of FtsH protein in Escherichia coli.

FtsH protein in Escherichia coli is an essential protein of 70.7 kDa (644 amino acid residues) with a putative ATP-binding sequence. Western blots (immunoblots) of proteins from fractionated cell extracts and immunoelectron microscopy of the FtsH-overproducing strain showed exclusive localization of the FtsH protein in the cytoplasmic membrane. Most of the FtsH-specific labeling with gold particles was observed in the cytoplasmic membrane and the adjacent cytoplasm; much less was observed in the outer membrane and in the bulk cytoplasm. Genetic analysis by TnphoA insertions into ftsH revealed that the 25- to 95-amino-acid region, which is flanked by two hydrophobic stretchs, protrudes into the periplasmic space. From these results, we concluded that FtsH protein is an integral cytoplasmic membrane protein spanning the membrane twice and that it has a large cytoplasmic carboxy-terminal part with a putative ATP-binding domain. The average number of FtsH molecules per cell was estimated to be approximately 400.

ATP-Dependent Proteases↗
PubMed1993

Localization of the human alpha 2-plasmin inhibitor gene (PLI) to 17p13.

We previously assigned the human alpha 2-plasmin inhibitor gene (PLI) to 18p11.1-->q11.2 by isotopic in situ hybridization. However, results obtained subsequently via Southern blot analysis of somatic cell hybrids and fluorescence in situ hybridization studies indicate that the gene is located at 17p13. Accordingly, we reassign PLI to 17p13.

Blotting, Southern↗
PubMed1993

Hypoglycemic activity of polygonati rhizoma in normal and diabetic mice.

The hypoglycemic effect of different dose of Polygonati Rhizoma, i.e., "Ousei", was investigated in both normal and streptozotocin-induced diabetic mice. The methanol extract of Polygonati Rhizoma (OM) (800 mg/kg) reduced the blood glucose of normal mice from 202 +/- 7 to 144 +/- 13 mg/100 ml 4 h after intraperitoneal administration (p < 0.01), and also lowered significantly the blood glucose of streptozotocin-induced diabetic mice from 589 +/- 34 to 396 +/- 15 mg/100 ml under similar conditions (p < 0.001). However, the hypoglycemic effects were not accompanied by any alteration in the serum insulin in these mice. OM also suppressed epinephrine-induced hyperglycemia in mice. These results support, therefore, the use of Polygonati Rhizoma in patients with diabetes and confirm its role as a traditional medicine. In addition, one of the active components of OM was identified as a spirostanol glycoside (PO-2).

Animals↗
PubMed1993

Spontaneous bacterial peritonitis in an adult patient with nephrotic syndrome.

Most cases of spontaneous bacterial peritonitis (SBP) in association with nephrotic syndrome are children. The complication of SBP in adults with nephrotic syndrome is extremely rare. Herein, we report a 25-year-old man with nephrotic syndrome and chronic renal failure who suffered from SBP. Citrobacter freundii was isolated from ascites. Irreversible deterioration of renal function followed the development of SBP, though the peritonitis was cured with antibiotic treatment. This case suggests that SBP is a rare, but serious complication of adult nephrotic syndrome with ascites.

Adult↗
PubMed1993

Glomerular alterations in experimental oliguric and nonoliguric acute renal failure.

Studies were performed in oliguric and nonoliguric forms of uranyl acetate (UA)-induced and ischemic acute renal failure (ARF) to examine whether a reduction in GFR is correlated with glomerular morphologic alterations. UA-induced nonoliguric and oliguric ARF were induced in rabbits by i.v. injections of 0.9 and 2 mg/kg, respectively. A 60-min renal artery clamping produced nonoliguric ARF in previously uninephrectomized rats, but oliguric ARF in the clamped kidneys of sham-nephrectomized animals. A decline in the whole-kidney CIn rate was more marked in oliguric ARF kidneys of both models than in nonoliguric ARF kidneys. Also, tubular damage was more pronounced in oliguric kidneys when compared with nonoliguric kidneys. Scanning electron microscopic observations revealed glomerular alterations in oliguric and nonoliguric kidneys in both models, evidenced by a flattening and spreading of podocyte cell bodies associated with loss of epithelial foot processes and a reduction in the density and diameter of endothelial fenestrae. There was no significant difference in these glomerular changes between oliguric and nonoliguric kidneys. The findings suggest that less reduction in the whole-kidney GFR in nonoliguric ARF kidneys is ascribed largely to less pronounced tubular damage rather than to less severe glomerular morphologic alterations.

Acute Kidney Injury↗
PubMed1993

[Multiple myeloma associated with diffuse parenchymal amyloidosis of the lung].

A 58-year-old woman was hospitalized in March, 1991, with slight breathlessness on exertion. Laboratory investigations revealed M-protein (IgG lambda type, 7,575mg/dl) in serum, and Bence-Jones proteinuria. Osteolytic bone lesions were noted roentgeno-logically. Bone marrow aspiration showed the presence of 19% of atypical plasma cells, and the case was diagnosed as multiple myeloma. The chest X-ray film showed bilateral diffuse micronodules, which were found by a transbronchial lung biopsy to be diffuse parenchymal amyloid deposits. The patient was treated with melphalan, prednisolone and interferon-alpha for 6 courses. Clinical symptoms improved but no decrease of the level of M-protein was observed. The patient is still alive without changes of pulmonary shadows on X-ray films for the past 2 years.

Amyloidosis↗
PubMed1993

[Neuropsychological findings of functional cortical mapping in patients with brain tumors].

In 3 patients with brain tumors involving language areas, we investigated functional cortical regions and epileptogenic foci using subdural electrode stimulation before operation. These stimulation studies were useful in preserving postoperatively their language function. The following neuropsychological findings were obtained; (1) Stimulation of Broca area (Brodmann 44 and 45) did not produce anarthria (phonetic disintegration), but semantic and phonemic parahasias and word finding difficulties. (2) Stimulation of lower motor cortex elicited anarthria. (3) Buccofacial apraxia was not produced only by stimulation of frontal operculum. (4) When anarthria was elicited by stimulation, difficulty in retrieving both Kana and Kanji letter-forms and paragraphia in Kana letters were sometimes observed. (5) Stimulation at Exner's writing centre did not produce writing deficits, but elicited word finding difficulties and paraphasias.

Adult↗
PubMed1993

[A case of recurrent colon cancer treated markedly effective with 5'-DFUR].

A 71-year-old male with recurrent colon cancer was admitted to our hospital with obstructive jaundice. Virchow's node metastasis was palpable in his neck. The enlarged intraabdominal lymphnodes due to recurrence and liver metastasis were demonstrated on computed tomography. Bile duct obstruction was treated by expandable metallic biliary endoprosthesis. 5'-DFUR (5'-deoxy-5-fluorouridine) was administered orally at 600 mg daily. Virchow's node metastasis completely disappeared by 46 days after administration of 5'-DFUR. The enlarged intraabdominal lymphnodes and liver metastasis disappeared on computed tomography. No significant side effects from 5'-DFUR were encountered for 18 months. 5'-DFUR appears to be a useful and safe treatment for recurrent colon cancer.

Administration, Oral↗