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Biomedical subjects

R Suzuki

Publications and source records attributed to R Suzuki.

At least 703 records · Page 39Linked to original sources
PubMed1984

[Total pelvic exenteration for primary and locally recurrent rectal cancer].

Thirteen patients with advanced carcinoma of the lower colon and no evidence of extrapelvic metastasis were submitted to total pelvic exenteration with urinary diversion. The operative mortality rate was 7.7%. Determinate 5-year survival rate of 40% was achieved. Local recurrence of rectal cancer following abdominoperineal resection is rarely amenable to limited resection. Six patients with deeply invading recurrent lesions had pelvic exenteration combined with sacral resection. This procedure seems a reasonable treatment for palliation and the chance of cure in selected patients. CT examination of the pelvis is very valuable for the early detection and localization of recurrence.

Adult↗
PubMed1983

DNA primase associated with 10 S DNA polymerase alpha from calf thymus.

Among multiple subspecies of DNA polymerase alpha of calf thymus, only 10 S DNA polymerase alpha had a capacity to initiate DNA synthesis on an unprimed single-stranded, circular M13 phage DNA in the presence of ribonucleoside triphosphates (DNA primase activity). The primase was copurified with 10 S DNA polymerase alpha through the purification and both activities cosedimented at 10 S through gradients of either sucrose or glycerol. Furthermore, these two activities were immunoprecipitated at a similar efficiency by a monoclonal antibody directed against calf thymus DNA polymerase alpha. These results indicate that the primase is tightly bound to 10 S DNA polymerase alpha. The RNA polymerizing activity was resistant to alpha-amanitin, required high concentration of all four ribonucleoside triphosphates (800 microM) for its maximal activity, and produced the limited length of oligonucleotides (around 10 nucleotides long) which were necessary to serve as a primer for DNA synthesis. Covalent bonding to RNA to DNA was strongly suggested by the nearest neighbour frequency analysis and the DNAase treatment. The DNA synthesis primed by the RNA oligomers may be carried out by the associating DNA polymerase alpha because it was strongly inhibited by araCTP, resistant to d2TTP, and was also inhibited by aphidicolin but at relatively high concentration. The primase preferred single-stranded DNA as a template, but it also showed an activity on the double-stranded DNA from calf thymus at an efficiency of approx. 10% of that with single-stranded DNA.

Animals↗
PubMed1983

Degeneration of CA1 neurons in hippocampus after ischemia in Mongolian gerbils: cyclic AMP-systems.

Bilateral ischemia induced by occlusion of the carotid arteries for 5 min causes a selective degeneration of CA 1 neurons of the hippocampus of Mongolian gerbils. The degeneration process is complete in 14 days as assessed by light microscopy. After one week, basal values for radioactive cyclic AMP in [3H]adenine-labeled tissue from the CA 1 region of hippocampus are greatly reduced as are the absolute magnitude of accumulations of cyclic AMP elicited by norepinephrine, 2-chloroadenosine and histamine. At 2 and 4 weeks, basal values for radioactive cyclic AMP have nearly attained control values and the response to 2-chloroadenosine is fully restored. The response of cyclic AMP-generating systems to norepinephrine is now significantly greater than in control, while the response to histamine remains reduced in magnitude. The ischemia has no effect on basal values for radioactive cyclic AMP or on responses in [3H]adenine-labeled slices from cerebral cortex. Histamine levels after ischemia are significantly increased above control in the CA 1 region. Basal and histamine-sensitive adenylate cyclase activity in the membrane preparations are slightly decreased during the first week after ischemia, followed by a recovery. There is an inverse correlation between histamine levels and adenylate cyclase activity in individual animals 4 days after ischemia.

Adenylyl Cyclases↗
PubMed1983

Myeloid differentiation antigen defined by a monoclonal antibody IF10.

A monoclonal antibody of IgM class that defines the antigen present on human peripheral blood granulocytes was produced and characterized. This monoclonal antibody (IF10) was made from a single fusion between P3-X63-Ag8-U1 (P3U1) myeloma cells and splenocytes from a BALB/c mouse immunized against human cultured monocytoid cell line THP-1 cells. IF10-defined antigen(s) was expressed on the cells of granulocyte lineage such as peripheral blood granulocytes and metamyelocytes, myelocytes, promyelocytes, and a part of myeloblasts in the normal bone marrow, whereas it was not detected on resting and activated T lymphocytes, B lymphocytes, adherent monocytes, and thymocytes. The IF10-defined antigen was also expressed on cultured monocytoid cell lines as well as myeloid and myeloid/erythroid (K-562) cell lines. T lymphoblastoid cell lines, particularly those representing the T cells at an early thymocyte level, and a part of null cell lines were also reactive to IF10. Therefore, IF10 may be a unique monoclonal antibody that defines an antigen(s) which is expressed on almost whole stages of granulocytes and early stages of macrophages and T-cell lineages, and possibly during very early stages of erythroid lineage.

Antibodies, Monoclonal↗
PubMed1983

Pelvic exenteration combined with sacral resection for recurrent rectal cancer.

Local recurrence of rectal cancer following abdominoperineal resection is rarely amenable to limited resection. Computed tomographic (CT) study of the pelvis revealed recurrent tumor images in relation to the adjacent pelvic structures. Five patients with deeply invading recurrent lesions were submitted to pelvic exenteration combined with sacral resection. No postoperative deaths were encountered. The postoperative sharp drops of serum CEA levels are useful for judging the adequacy of this procedure. The follow-up status of the 5 patients, respectively: 14 months alive with pulmonary metastasis, 9 months alive without symptoms but with slightly elevated CEA levels, and 8 months, 3 months, and 3 weeks alive with no evidence of disease. All patients who were relieved of perineal or sciatic nerve pain are now able to walk without any assistance or trouble. Total en bloc residual pelvic exenteration combined with sacral resection is a reasonable treatment for locally recurrent rectal cancer.

Aged↗
PubMed1983

Increased glycosylation of proteins from cataractous lenses in diabetes.

The rates of glycosylation of lens proteins were determined in extracts of human 'diabetic' and 'senile' cataractous lenses by a method employing thiobarbituric acid. Incubation of soluble lens proteins (6,500 X g supernatant of homogenates) in vitro with various concentrations of D-glucose in sodium phosphate buffer (50 mmol/l, pH 7.2) resulted in a gradual glycosylation which was time and concentration dependent. Glycosylated proteins from the cataractous lenses of 21 senile and 12 diabetic subjects afforded 0.72 +/- 0.22 and 1.84 +/- 0.44 nmol 5-hydroxymethylfurfural/mg protein (mean +/- SD), respectively. The value is significantly higher in the diabetic than in the senile group (p less than 0.001), although the mean age of the diabetic patients (67 years) was significantly younger than that of senile subjects (75 years; p less than 0.01). These results indicate that human lens proteins can be glycosylated both in vitro and in vivo, and that hyperglycaemia can accelerate the non-enzymatic glycosylation of lens proteins in diabetic patients.

Aged↗
PubMed1983

The effects of 5-minute ischemia in Mongolian gerbils: I. Blood-brain barrier, cerebral blood flow, and local cerebral glucose utilization changes.

Changes in morphology, behavior of the blood-brain barrier (BBB), regional cerebral blood flow (rCBF), and local cerebral glucose utilization (LCGU) were assessed and correlated in Mongolian gerbils following 5 min cerebral ischemia, produced by bilateral clamping of the common carotid arteries. The morphological changes were confined to the hippocampus and revealed a conspicuously delayed destruction of the CA1 neurons, occurring after 3 days. Following release of carotid occlusions, there were two separate openings of the BBB. One, occurring shortly after recirculation, was associated with focal hyperemia in the cerebral cortex, hippocampus and basal ganglia; the second opening was observed after several days and was associated with severe neuronal destruction in the CA1 sector. Correlation of quantitative and qualitative rCBF assays with 14C-deoxyglucose autoradiographic observations indicated an uncoupling between blood flow and glucose metabolism, observed in the hippocampus at 10 min after recirculation. The described changes provide a further insight into the post-ischemic events which determine the outcome of ischemic injury.

Animals↗
PubMed1983

The effects of 5-minute ischemia in Mongolian gerbils: II. Changes of spontaneous neuronal activity in cerebral cortex and CA1 sector of hippocampus.

Spontaneous neuronal activity was recorded in the cerebral cortex and the CA1 sector of the hippocampus in gerbils during and after 5-min ischemia, produced by bilateral clamping of the common carotid arteries. It was found that spontaneous activity in both cortical and CA1 neurons ceased within 60s after the onset of ischemia and that it began to reappear 10-20 min after the recirculation. During the next 24 h most CA1 neurons which were recorded showed hyperactivity. This was evident primarily by an increase in spike discharges, whereas recordings from the cerebral cortex were within the preocclusion ranges. On the 2nd day after ischemia, functioning CA1 neurons could not be found, as if they were in a state of functional death, although histological sections showed a general preservation of their cellular structure at that time.

Animals↗
PubMed1983

Response of bovine intra-ocular muscles to transmural stimulation in the presence of various prostaglandins.

Effects of prostaglandins (PGs) E1, E2 and F2 alpha on the electrically stimulated and non-stimulated smooth muscles of bovine intra-ocular tissues were investigated in vitro. PGs E1, E2 and F2 alpha contracted the sphincter and these contractions were not antagonized by either cholinergic or adrenergic blocking agents. PGF2 alpha was much weaker than PGE1 or PGE2. PGs in high concentrations produced an irreversible contracture of the sphincter muscle. In contrast, the dilator muscle contracted with PGF2 alpha, but not PGE1 or PGE2. The ciliary muscle did not respond to these PGs or to indomethacin. Electrical field stimulation with short pulses produced excitation of the intrinsic nerves. The responses produced were not altered in amplitude by the application of any dose of PGs or indomethacin, although indomethacin did lower the tone of the sphincter. PGs did not influence the amplitude of the acetylcholine-induced responses of the intra-ocular muscles. These results indicate that in each of the bovine intra-ocular muscles, PGs play a minor role in neuromuscular transmission both prejunctionally and postjunctionally. Thus, PG-induced contractions of the bovine intra-ocular muscles are considered to occur by a direct action on the muscle rather than on the nerves.

Action Potentials↗
PubMed1983

Growth of a cultured leukemia subline was promoted by conditioned medium of thymic reticuloepithelial-like cells (B6TE).

A murine leukemia subline (L17R) was selectively developed in the presence of conditioned medium of a thymic reticuloepithelial-like cell line (B6TE). Cytotoxicity tests and immunofluorescence microscopy showed that L17R cells were negative in the expression of Thy 1.1, Lyt 1.2 and terminal deoxynucleotidyl transferase (TdT), however, 35% positive in Lyt 2.1 phenotype, and 95% positive in the expression of peanut agglutinin (PNA) receptor. B6TE conditioned medium had no activity of interleukin 1 (IL 1), interleukin 2 (IL 2), interleukin 3 (IL 3) and granulocyte/macrophage colony-stimulating factor (GM-CSF). When L17R leukemic cells were plated at a low cell density, their growth was accelerated 40 times by the addition of concentrated B6TE culture supernatant. This growth activity, tentatively designated leukemia-growth-promoting factor (LGPF), was heat sensitive, and its mol. wt was estimated to be approx. 25,000 from the elution pattern of Sephadex G-100 chromatography.

Animals↗
PubMed1983

Neuronal influence on the mechanical activity of the ciliary muscle.

1 Neuronal effects and the pharmacological properties of the bovine ciliary muscle were investigated in vitro. The bovine ciliary muscle exhibited no spontaneous activity. 2 Electrical stimulation of an isolated short ciliary nerve produced distinct contractions. The minimal stimulus duration required to evoke a contraction was 0.2 ms and amplitude of the contraction was maximal at 2 ms. Twitch or incomplete tetanus reached a complete tetanus with 4 Hz stimulation. 3 Raising the external potassium concentration from 5.9 to 158.8 mM produced a contracture which consisted of an initial phasic and then tonic components. 4 The contractions generated by either electrical stimulation (0.2-100 ms) or high K were potentiated by physostigmine and completely inhibited by atropine. Neither adrenoceptor agonists nor blockers influenced these contractions. 5 Application of tetraethylammonium (TEA), potentiated the electrically-induced ciliary muscle contraction, and the effect of TEA was not completely inhibited by high concentrations of either atropine or tetrodotoxin. Thus, TEA presumably acts both pre-junctionally and post-junctionally to increase the contractile development of ciliary muscle. 6 The ciliary contractile response is primarily mediated by acetylcholine released from nerves, and this response is accompanied by a negligible contribution from the sympathetic nerves. Depolarization induced by electrical currents or by high K was ineffective in evoking contraction of the ciliary muscle. 7 The results suggest that excitation of the ciliary muscle is probably mediated via junction potentials or by a direct transmitter action without any very great change in the potential. Action potentials are probably generated in the presence of TEA.

Animals↗