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Biomedical subjects

T Sakai

Publications and source records attributed to T Sakai.

At least 19 recordsLinked to original sources
PubMed1992

Simple, rapid and sensitive determination of plasma taurine by high-performance liquid chromatography using pre-column derivative formation with fluorescamine.

A simple, rapid and sensitive method for the determination of plasma taurine by high-performance liquid chromatography in the isocratic mode has been developed. The deproteinized plasma was treated with fluorescamine. These derivatives were separated on a LiChrospher 100 RP-8 column within 15 min. The detection limit for taurine was 0.2 microM. The plasma taurine contents of yellowtail fish, Seriola quinqueradiata, beef cattle, dairy cows and chickens were determined to be 125 +/- 54, 5.6 +/- 1.4, 2.2 +/- 0.7 and 20.0 +/- 9.6 micrograms/ml, respectively.

Animals↗
PubMed1992

Cloning of 67-kDa laminin receptor cDNA and gene expression in normal and malignant cell lines of the human lung.

Cell-adhesive protein laminin and its specific receptor play an important role in the processes of cancer proliferation, invasion and metastasis. In the present study, we cloned the cDNAs of the 67-kDa laminin receptor both from a human lung cell line (IMR90) and from a human lung cancer cell line (SBC3), and determined the nucleotide sequences. In comparison with both cDNA sequences of the protein-coding region, three nucleotide differences were found. These differences in the secondary structure of the protein, however, were caused by nucleotide substitutions. It was also demonstrated that the level of 67-kDa-laminin receptor mRNA was higher in SBC3 than in IMR90.

Amino Acid Sequence↗
PubMed1992

Mapping of the nu gene using congenic nude strains and in situ hybridization.

The chromosomal location of the nu gene, which is responsible for hairlessness and athymus, was determined using six DNA markers (interleukin 3 [Il-3], Myhs, Acrb, Evi-2, Mpo, and Hox-2) on mouse chromosome 11. We constructed the high-resolution physical mapping of the six DNA markers on chromosome 11 by in situ hybridization using fluorescence-labeled cosmid probes. The results indicate the order of centromere-(41cM)-Il-3-(3cM)-Myhs- (4cM)-Acrb-(6cM)-Evi-2-(3cM)-Mpo-(5cM)- Hox-2. We have used congenic nude strains and examined which of the six DNA markers were derived from the original nude mouse. We found the Evi-2 locus is linked to the nu gene in all the informative, independent congenic nude strains. From these data, we could estimate the location of the nu gene, not only genetically but also physically within a region that spans approximately 17 megabases (9 cM) between the Acrb and Mpo genes.

Animals↗
PubMed1992

Increased expression of the 67kDa-laminin receptor gene in human small cell lung cancer.

Gene expression of the precursor of the 67kDa-laminin receptor was examined by Northern analysis using 11 established human lung cancer cell lines and 25 lung cancer tissues obtained by operation. As a result, one transcript, the size of which was 1.2 kb was shown in all cell lines and tissues examined. An increased level of mRNA was demonstrated in cell lines which proliferated rapidly and in small cell lung cancer cell lines. It was also indicated that gene expression of the laminin receptor was up-regulated especially in small cell lung cancer tissue. In this context, 67kDa-laminin receptor appears to be a marker for biological aggressiveness of human lung cancer.

Adenocarcinoma↗
PubMed1992

The glomerular mesangium: capillary support function and its failure under experimental conditions.

We present a structural analysis of the ability of the biomechanical unit consisting of mesangium and glomerular basement membrane to maintain normal capillary architecture in the face of mechanical challenges due to high intraglomerular pressures. Capillary support function may be considered in terms of the stabilization of local form (development of wall tension against capillary dilation) and global form (centripetal fixation of capillary loops to maintain higher order form). The pathologic consequences of the loss of this support are illustrated by way of experimental models of mechanical mesangial failure. Such failure may express itself as mesangial widening, increased transmesangial macromolecule "traffic," ballooning of capillary segments, and unfolding of capillary loops. Mechanisms are described by which these structural changes may lead to segmental glomerular sclerosis.

Animals↗
PubMed1992

Structural relationships between the endothelial actin system and the underlying elastic layer in the distal interlobular artery of the rat kidney.

The structure of the intracellular actin filaments and the extracellular matrices was studied in the distal interlobular arteries in the rat kidney, employing three different morphological techniques, including rhodamine-phalloidin staining of cryosections, resorcin-fuchsin staining of paraffin sections, and a cold dehydration procedure for electron microscopy. The endothelial cells possess longitudinally running stress fibers. The inner elastic layer is composed of meshworks of elastic fibers encompassing numerous pores. The smooth muscle cells containing abundant actin filaments are arranged circumferentially around the vascular axis. The endothelial stress fibers are found mainly in the basal half of the endothelial cells, and anchor onto the basal cell membranes. The elastic meshworks send off longitudinal branch fibers to contact the endothelial cell membranes at the anchoring sites of stress fibers. In addition circumferential branches run toward the smooth muscle cells. The functional significance of the intracellular contractile apparatus and the extracellular tensile component in small arteries was discussed.

Actins↗
PubMed1992

Radical lymphadenectomy for rectal cancer facilitated by a carbon particle infusion lymphangiography.

For the intraoperative visualization of the para-aortic nodes and those around the iliac vessels, a fine carbon particle solution was infused into the bilateral pedal lymphatic vessels of 12 patients with rectal carcinoma. A low anterior resection with radical lymph node dissection was then performed while preserving pelvic autonomic nerves. Of 444 lymph nodes removed from the iliac arterial region, 430 were stained with carbon black (96.8%), even though the black staining was not perfect in the nodes of the inferior mesenteric arterial region. All of the lateral black stained nodes were clearly visible and hence could be easily excised. The average number of dissected nodes in one patient was 43.8 in this dissection with carbon particle infusion, which was larger than those of conventional lymph node dissection. We then examined the length of time that a postoperative indwelling bladder catheter was needed as an indication for autonomic nerve damage, and it was ascertained that less damage occurred in this operation compared to other types of dissections, such as conventional or extended lymph node dissection.

Carbon↗
PubMed1992

Acute and subacute inhalation toxicity of silane 1000 ppm in mice.

Male ICR mice were exposed to silane 1000 ppm, a concentration 200 or 2000 times higher than the recommended occupational exposure limits by many countries and academic associations, for 1, 2, 4, and 8 h (phase I study) and for 6 h/day, 5 days/week, over 2 and 4 weeks (phase II study). Hematological and biochemical studies were performed, and the animals were examined for histopathological lesions of the cornea, nasal cavity, respiratory tract, lung, liver, kidney, spleen, pancreas, thymus, thyroid, bone marrow, salivary glands, esophagus, and testis. All mice in both studies survived until they were sacrificed. In the phase I study, no exposure-related changes were found as a result of the hematological, biochemical, or histopathological examinations. In the phase II study, hematological and biochemical examinations failed to reveal any exposure-related changes, but mild irritation, manifested in the form of a small amount of exudate (eight out of ten animals), and inflammatory cells and/or necrotic cells on the nasal mucosa (six out of ten animals) was observed in the mice exposed to silane for 4 weeks. These findings suggest that silane toxicity and irritation are not severe.

Administration, Oral↗
PubMed1992

Recurrence of superficial bladder tumours after transurethral resection.

From 1979 to January 1990, 48 patients with newly diagnosed superficial bladder tumours were treated by transurethral resection (TUR) at Toyama Medical and Pharmaceutical University Hospital. The relationship between tumour recurrence and the stage, grade, number, or size of the tumours was investigated. The 1-, 2-, 3-, 4- and 5-year non-recurrence rates were 72%, 63%, 47%, 40%, and 40%, respectively. Non-recurrence rate for pTa tumours was significantly higher than that for pT1 tumours (p < 0.05). There was no relationship between tumour grade and recurrence. The rate of recurrence of multiple tumours was higher than that of single ones. There was no difference in non-recurrence rate between tumours smaller than 1 cm and those of 1 cm or larger. Non-recurrence rate in the instillation therapy group was significantly higher than in the non-instillation group (p < 0.05). It was concluded that patients with multiple or high-stage tumours have the risk of a high rate of recurrence and that intravesical chemotherapy is effective in preventing local recurrence in some patients.

Administration, Intravesical↗
PubMed1992

Overlap and discrepancy between tests for anti-C100, anti-GOR and anti-CP9 in patients with chronic liver disease and inhabitants in Saga, Japan.

The authors evaluated the clinical significance of anti-C100, anti-GOR and anti-CP9 in hepatitis C virus (HCV)-related liver disease in two populations: 459 healthy subjects and 385 patients with chronic liver disease (CLD). Previously we reported high rates of mortality and morbidity (5.3%) of CLD in subjects in Saga, Japan. This was ascribed to the high prevalence (10.8%) of anti-HCV among randomized populations, as detected by the C100 ELISA test system, as compared with a finding of 2-3% in Japanese blood donors in the same decade. The incidence of anti-C100, anti-GOR and anti-CP9 detected by ELISA test system in the healthy population currently surveyed was 17.0%, 19.2% and 32.0% respectively, as compared with 75.3%, 60.3% and 73.0% respectively, in those with CLD. The incidence of positivity for at least one of the three antibodies was high (36.4%) among healthy subjects, and even higher (86.5%) among the patients with CLD. In the healthy subjects, incidence of positivity increased with age. The healthy and CLD populations differed in the proportion of cases positive for all three antibodies vs. those positive for at least one antibody: healthy subjects, 52/167, 31.1%, vs. CLD patients, 197/333, 59.2%; P less than 0.01. Among the anti-C100-positive healthy cases, these was a significantly high level of AST, ALT, ZTT and gamma GTP compared with negative cases, with or without anti-GOR and anti-CP9 (P less than 0.01-0.05). These observations suggest that the presence of anti-C100 may be related to the active state of HCV-related liver disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Different protein kinase C isozymes could modulate bradykinin-induced extracellular calcium-dependent and -independent increases in osteoblast-like MC3T3-E1 cells.

Effects of protein kinase C (PKC) on bradykinin (BK)-induced intracellular calcium mobilization, consisting of rapid Ca2+ release from internal stores and a subsequent sustained Ca2+ inflow, were examined in Fura-2-loaded osteoblast-like MC3T3-E1 cells. The sustained Ca2+ inflow as inferred with Mn2+ quench method was blocked by Ni2+ and a receptor-operated Ca2+ channel blocker SK&F 96365, but not by nifedipine. The short-term pretreatment with phorbol 12-myristate 13-acetate (PMA), inhibited BK-stimulated Ca2+ inflow, and the prior treatment with PKC inhibitors, H-7 or staurosporine, enhanced the initial internal release and reversed the PMA effect. Moreover, 6 h pretreatment with PMA caused similar effect on the BK-induced inflow to that obtained with PKC inhibitors, whereas 24 h pretreatment was necessary to affect the internal release. On the other hand, the translocation and down-regulation of PKC isozymes were examined after PMA treatment of MC3T3-E1 cells by immunoblot analyses of PKCs with the isozyme-specific antibodies. 6 h treatment with PMA induced down-regulation of PKC beta, whereas longer treatment was needed for down-regulation of PKC alpha. Taken together, it was suggested that the BK-induced initial Ca2+ peak and the sustained Ca2+ inflow through the activation of a receptor-operated Ca2+ channel, are differentially regulated by PKC isozymes alpha and beta, respectively, in osteoblast-like MC3T3-E1 cells.

Animals↗
PubMed1992

Changes in plasma atrial natriuretic peptide concentration during heart transplantation.

Examination of changes in plasma atrial natriuretic peptide (ANP) concentrations during heart transplantation may provide important information about factors influencing plasma ANP in patients with severe heart failure. Serial changes in plasma ANP during heart transplantation, and atrial content of ANP in native and donor atria, were measured in 12 patients. Preoperative plasma ANP was elevated in all patients (387 +/- 77 pg/mL), whereas atrial content of ANP in native atria was reduced (0.36 +/- 0.082 micrograms/mg protein). Preoperative plasma ANP did not correlate with hemodynamics, but was negatively correlated with creatinine clearance (r = -0.76, P < .01). Intraoperative plasma ANP prior to transplantation was strongly correlated with intraoperative plasma ANP after transplantation (r = 0.84, P < .001). Although postoperative plasma ANP was reduced from preoperative plasma ANP by 75%, these two measurements were also significantly correlated (r = 0.70, P < .02). Postoperative plasma ANP was not correlated with hemodynamics, but was negatively correlated with both creatinine clearance (r = -0.65, P < .05) and content of ANP in the native atria (r = -0.75, P < .01). Multiple linear regression analysis suggested that up to 85% of the variability of early postoperative plasma ANP could be accounted for by the variability in these latter two parameters. The decrease in native atrial ANP content, in the context of elevated plasma ANP concentration, is consistent with prior animal studies suggesting that severe heart failure induces cellular adaptations favoring accelerated ANP synthesis and secretion (with resultant reduction in tissue content).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Effects of NZ-105, a new calcium antagonist, on renal function in anesthetized spontaneously hypertensive rats.

The effects of a new dihydropyridine derivative, NZ-105, on renal function were investigated in anesthetized spontaneously hypertensive rats. Intravenous injection of NZ-105 (0.01 and 0.03 mg/kg of body weight) significantly increased the urine flow rate (UV) and renal absolute excretion of sodium and chloride. Potassium excretion also increased significantly, but it was relatively slight in comparison with sodium or chloride excretion. There was a decrease in mean blood pressure (-14.5 +/- 2.3 and -22.3 +/- 3.4 mm Hg, 20 min after the administration of 0.01 and 0.03 mg/kg of body weight, respectively). The glomerular filtration rate (GFR) was not changed; however, the renal plasma flow (RPF) was significantly increased. The tubular site of action of NZ-105 was investigated by the lithium clearance technique. Intravenous injection of NZ-105 inhibited sodium reabsorption beyond the proximal tubules about four to five times more effectively than at the proximal tubules. In conclusion, intravenous administration of NZ-105 in anesthetized spontaneously hypertensive rats caused diuretic and natriuretic action. The possible site of diuretic action may be mainly at the nephron segments beyond the proximal tubules.

Anesthesia↗
PubMed1992

Thenar and hypothenar muscles and their innervation by the ulnar and median nerves in the human hand.

The thenar and hypothenar muscles as well as their supplying nerves were analyzed with an improved dissecting method. Among the four thenar muscles, the m. abductor pollicis brevis (AbPB) has a separate muscle belly, whereas the m. opponens pollicis (OP), the superficial and deep heads of the flexor pollicis brevis (sFPB and dFPB), and the adductor pollicis (AdP) are fused with each other to make a single mass (deep thenar muscle group). These muscles are innervated by branches of the recurrent nerve and the accessory recurrent nerve from the median nerve as well as by terminal branches of the deep branch (ramus profundus) of the ulnar nerve. These three nerves frequently form a loop within the deep thenar muscle group (thenar loop), and a branch to the OP and one to deep parts of the sFPB often make a smaller loop (intrathenar loop), whereas the AbPB receives a separate nerve branch. Among the hypothenar muscle, the m. abductor digiti minimi and the m. flexor digiti minimi brevis are fused with each other, and their supplying nerves frequently form a loop in these muscles (intrahypothenar loop), whereas the m. opponens digiti minimi is separated from the others and receives a separate nerve branch. In the distribution pattern of supplying nerves to the thenar and hypothenar muscles, we find regularities in that they branch off in a regular manner from the ulnar and the median nerve, and that nerve branches to those muscles with fused bellies frequently communicate with each other to make loops.

Hand↗