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Biomedical subjects

N Seki

Publications and source records attributed to N Seki.

At least 235 records · Page 13Linked to original sources
PubMed1990

Pinacidil inhibits neuromuscular transmission indirectly in the guinea-pig and rabbit mesenteric arteries.

1. Effects of pinacidil were investigated on neuromuscular transmission in smooth muscle tissues of the rabbit and guinea-pig mesenteric arteries by both electrophysiological procedures and a bioassay of noradrenaline (NA) outflows. 2. Pinacidil (over 1 microM) hyperpolarized smooth muscle cell membranes in both tissues, in a concentration dependent manner. Pinacidil hyperpolarized and increased the ionic conductance of smooth muscle membrane more markedly in the rabbit mesenteric artery than in the guinea-pig. The hyperpolarization induced by pinacidil occurred in the presence or absence of endothelial cells and was blocked by glibenclamide. 3. Perivascular adrenergic nerve stimulation produced excitatory junction potentials (e.j.ps) and repetitive stimulation produced a facilitation of e.j.ps in both tissues. Pinacidil (over 1 microM) reduced the amplitude and the decay time of e.j.ps to a consistently greater extent in the rabbit mesenteric artery than in the guinea-pig. However, the facilitation process of e.j.ps was not modified following application of pinacidil (1 microM). The pinacidil-induced inhibition of e.j.ps was prevented by pretreatment with glibenclamide. 4. Pinacidil (30 microM) marginally increased the overflows of NA and its metabolite, 3,4-dihydroxyphenylglycol (DOPEG) released following repetitive perivascular nerve stimulations. 5. Pinacidil (10 microM) partly inhibited the voltage-dependent Ca channel, as estimated from the recovery process following removal of pinacidil, of action potentials evoked on e.j.ps. 6. It is concluded that pinacidil increases ionic conductance and hyperpolarizes smooth muscle cell membranes of the guinea-pig and rabbit mesenteric arteries and as a consequence, inhibits the neuromuscular transmission process occurring on adrenergic nerve stimulation with no reduction in the amount of released transmitter.

Animals↗
PubMed1990

[Liver abscesses successfully treated by intraportal administration of amphotericin B in a case of acute myeloblastic leukemia (M2)].

A 46-year-old male was admitted to our hospital because of relapse of acute myeloblastic leukemia (M2). Remission was successfully reinduced after reinduction chemotherapy consisting of daunorubicin, cytosine arabinoside, etoposide and vincristine, but was complicated by neutropenia. After the therapy, the patient had persistent fever of about 38 degrees C despite broad-spectrum antibiotics therapy and the patient developed pain in the right quadrant of the abdomen. The white blood cell count rose to 23000/mm3. Liver function tests showed abnormal findings mainly consisting of an elevated serum alkaline phosphatase level. Ultrasonography showed multiple hypoechoic lesions in the liver and CT scans also revealed multiple low density areas. Therefore he was suspected of having a complication of liver abscesses. Amphotericin B was administered 75 mg/day intravenously every other day. A percutaneous liver biopsy was performed, but was not diagnostic. Blood cultures were negative for pathogens. Amphotericin B was administered up to a cumulative dosage of 2.3 g, but the patient remained febrile. Then he had an exploratory laparotomy and an open liver biopsy. The liver biopsy samples showed fungal elements proved by PAS staining. A catheter was inserted into the portal vein. Administration of Amphotericin B was started 20 mg daily through the catheter. The temperature fell to normal after institution of this therapy. The abnormal findings in CT scans almost disappeared and the inflammatory findings became negative after he had received intraportal administration of Amphotericin B over three months. Through the analysis of this case study, we confirmed that the intraportal administration of Amphotericin B was effective to the intractable liver abscesses due to fungi.

Amphotericin B↗
PubMed1990

Electrical properties of smooth muscle cell membrane in renal pelvis of rabbits.

Intracellular recordings were made to study the electrical properties of smooth muscle cells in the rabbit renal pelvis. The muscle cells exhibited spontaneous oscillation in the membrane potential (slow wave). The slow waves were regular and were resistant to tetrodotoxin and sympathomimetic or parasympathomimetic antagonists, findings indicative of myogenic activity. The membrane was depolarized by an increase in extracellular concentration of K+ ([K+]o), decrease in [Na+]o, inhibition of the electrogenic Na(+)-K+ pump by ouabain or K(+)-free solution, and the application of norepinephrine (NE, greater than 10(-6) M). The maximum slope of the membrane depolarization produced by a 10-fold increase in [K+]o was approximately 48 mV. Reductions in [Ca2+]o inhibited the generation of slow waves with no marked change in the membrane potential. Depolarizations produced by any given method increased the frequency and decreased the amplitude of the slow wave, and NE had the most potent accelerating action on the frequency. Hyperpolarization of the membrane by 1-5 mV with extracellularly applied current stimuli reduced the frequency, and a strong hyperpolarization (greater than 5 mV) blocked the generation of slow waves. Electrophysiological properties of the slow waves obtained with tissues of the renal pelvis and intestinal smooth muscles were compared.

Animals↗
PubMed1990

Transmitter release modulated by isoprenaline in the dog isolated mesenteric vein.

1. The effects of isoprenaline on the release of transmitter substances from perivascular adrenergic nerves were estimated from the excitatory junction potential (ejp) and outflow of noradrenaline in the dog mesenteric vein. 2. Isoprenaline increased the ejp amplitude and decreased the evoked release of noradrenaline. Yohimbine potentiated the former and converted the latter to an increased outflow. 3. Therefore, stimulation of prejunctional beta-adrenoceptor by isoprenaline increases the release of noradrenaline from perivascular adrenergic nerves. 4. Possible involvement of prejunctional alpha-adrenoceptors in the isoprenaline-induced modulation of transmitter release was also suggested.

Action Potentials↗
PubMed1990

[A comparative clinical trial of UFT medication and intravesical BCG in the recurrence of superficial bladder cancer. Study Group of UFT and BCG adjuvant therapy for bladder cancer].

In sixty-four patients who had TUR-bt for superficial bladder cancer, the effect of intravesical BCG and UFT medication were compared. Group A (n = 20) were treated with BCG, group B (n = 22) were treated with UFT and group C (n = 22) were treated with both agents. The patients were followed up for more than 12 months by cystoscopy at a interval of 3 months, urinary cytology and bladder cold cup biopsy, if necessary. Thirteen of the 20 patients in group A and 13 of the 22 patients in group B were free of tumors, compared to 5 of the 22 patients in group C. Although the recurrence-free-rate in each group does not differ significantly, the combination therapy of intravesical BCG and UFT medication seems to decrease the rate of tumor recurrence for superficial bladder cancer. Side effects of BCG and UFT were tolerated well.

Administration, Intravesical↗
PubMed1990

[Experience in the use of Kyosera Injection Port as a kind of implantable reservoir (the second report)].

A total of 30 pieces of Kyosera Injection Port, as a kind of implantable reservoir, was used in 29 cases of liver tumor for an intermittent repeated chemotherapy. Of these 27 cases were actually used between Aug. 1st, 1986 and Aug. 31st, 1989. In this paper we studied the safety of the reservoir. The observation period averaged 259.4 days, with the highest of 760 days and the lowest of 29 days. The injection times averaged 12.7 times, with the maximum of 40 times and the minimum of one. The reservoir was placed under the laparotomy, and the cases which underwent cholecystectomy were 93.1%. 16 cases were treated with intraarterial infusion, and 14 with intraportal infusion. We investigated the complication of Kyosera Injection Port in 27 cases. As a result, there were no complication such as catheter occlusion and infection via catheter. But of 27 cases, 8 cases were recognized a complication, and the rate was 29.6%. Lumbago was noted during infusion chemotherapy in three cases, and on the other hand, there were steatolysis and necrosis of the tissue surrounding the implantation site, a movement of port, a catheter out of vessel, a leakage of the drug, and intraabdominal bleeding after taking off the catheter. But of 8 complication cases, only two cases were not able to inject drug. As a result, the rate of complication was 70.4% in over all. On the other hand, of 27 cases, there were 5 cases which recognized the complication caused by reservoir in itself. The safety rate was 81.5%. In such a circumstance this reservoir was very safe and seemed suitable to the implantable reservoir.

Adult↗
PubMed1989

Enhanced production of interleukin-6 in mice with type II collagen-induced arthritis.

We established an interleukin-6 (IL-6)-dependent cell line from murine plasmacytoma MOPC-104E cells. This cell line (designated PIL-6) was found to respond to murine and to human IL-6, but not to any other cytokines. We used this cell line to investigate the involvement of IL-6 production in type II collagen-induced arthritis in DBA/1 mice. Only marginal IL-6 activity was detected in sera from DBA/1 mice inoculated with Freund's complete adjuvant (FCA) alone, with an unrelated protein (bovine serum albumin) plus FCA, or with type II collagen plus Freund's incomplete adjuvant. However, enhanced IL-6 activity was observed in DBA/1 mice that had been injected with type II collagen plus FCA to induce arthritis. The elevated level of serum IL-6 activity was associated with high levels of IL-6 produced when lymph node cells from arthritic mice were stimulated in vitro with type II collagen. We also found that the L3T4+ T cell subset is responsible for the enhanced production of IL-6 in arthritic mice. The results are discussed in the context of potential roles of IL-6 in the induction and/or expression of chronic, progressive arthritis.

Animals↗
PubMed1989

X-ray- and mitomycin C (MMC)-induced chromosome aberrations in spermiogenic germ cells and the repair capacity of mouse eggs for the X-ray and MMC damage.

Chromosome aberrations induced at the first-cleavage metaphase of eggs fertilized with sperm recovered from spermiogenic cells which had been X-irradiated and treated with mitomycin C (MMC) at various stages were observed using in vitro fertilization and embryo culture technique. Furthermore, the repair capacity of the fertilized eggs for X-ray- and MMC-induced DNA damage which was induced in the spermiogenic cells and retained in the sperm until fertilization was investigated by analysis of the potentiation effects of 2 repair inhibitors, 3-aminobenzamide (3AB) and caffeine on the yield of chromosome aberrations. The frequency of chromosome aberrations observed in the eggs fertilized with sperm recovered from the early spermatid to late spermatocyte stage with X-irradiation of 4 Gy (16-20 days after X-irradiation) was markedly higher than that in the eggs fertilized with sperm recovered from spermatozoa to late spermatid stage (0-8 days after X-irradiation). The induced chromosome aberrations predominantly consisted of chromosome-type aberrations, the main type being chromosome fragment followed by chromosome exchange through all the spermiogenic stages. On the other hand, a high frequency of chromosome aberrations was not induced through all the stages with MMC treatment of 5 mg/kg. The remarkable potentiation effects of 3AB and caffeine were found in the eggs fertilized with sperm recovered from almost all the spermiogenic stages after X-irradiation. In the MMC treatment, a remarkable caffeine effect was observed occasionally in mid-early spermatids to late spermatocytes where a large amount of MMC damage could be induced. These results suggest that the large amount of DNA lesions induced in spermiogenic cells by X-rays and MMC persist as reparable damage until sperm maturation and are effectively repaired in the cytoplasm of the fertilized eggs.

Animals↗
PubMed1989

Mechanism of chromosome aberration induction in the mouse egg fertilized with sperm recovered from postmeiotic germ cells treated with methyl methanesulfonate.

Chromosome aberrations induced in spermatozoa to late spermatocytes following treatment with methyl methanesulfonate (MMS) were examined at the first-cleavage metaphase of fertilized eggs in an attempt to clarify the mechanism of chromosomal damage in postmeiotic germ cells. A high frequency of chromosome aberrations was induced in early spermatozoa to mid spermatids, while few chromosome aberrations were observed in early spermatids to late spermatocytes. 3-Aminobenzamide (3AB) potentiated the effect of MMS-induced chromosome aberrations in spermatozoa to mid spermatids indicating that a large amount of DNA lesions produced at these stages during spermatogenesis were not repaired prior to fertilization of the oocytes. Furthermore, from the cell-cycle analysis of the repair capacity in the fertilized egg it became clear that the lesions which remained in sperm until fertilization could be divided into 2 types: (1) DNA-strand breaks induced by stress in the chromatin structure produced by protamine alkylation; these lesions were converted to chromosome-type aberrations by 3AB treatment of the eggs during G1 phase; and (2) alkylated DNA which produces apurinic or apyrimidinic sites, of which there were a significant number mainly converted to chromatid exchanges by 3AB treatment of the eggs during S phase. This type of lesion appears to be constantly induced through all spermiogenic stages in contrast to the former type of lesion which is induced specifically during the stage of protamine maturation.

Animals↗
PubMed1989

Benign prostatic hyperplasia in a patient castrated in his youth.

We report a case of benign prostatic hyperplasia in a 60-year-old patient who had been castrated when he was 30 years old. The prostatic tissue, which consisted of cystic and fibromuscular hyperplasia, contained no significant concentration of androgen receptors. Only 1 such case was reported previously in the literature.

Age Factors↗
PubMed1989

Changes in X-ray sensitivity of mouse eggs from fertilization to the early pronuclear stage, and their repair capacity.

To study the changes in radiosensitivity of male and female genomes from fertilization to the pronuclear stage, the frequency of induced chromosome aberrations was examined at the first-cleavage metaphase in eggs fertilized with X-irradiated sperm, in eggs X-irradiated at the mature oocyte stage immediately before fertilization, and in fertilized eggs exposed to X-rays at various stages before DNA synthesis (1-5 h after insemination). Gametic treatment, fertilization and embryo culture were carried out in vitro. Most of the induced chromosome aberrations were chromosome-type aberrations, the frequency of chromosome fragments being the highest, followed by chromosome exchanges in both sperm and oocytes. The induction of chromosome-type aberrations was much higher in oocytes than in sperm. Chromosome-type aberrations were the main type also in fertilized eggs irradiated at the pre-DNA-synthetic stage. The radiosensitivity increased gradually with pronuclear formation (1-4h after insemination), but little difference in radiosensitivity was observed between eggs irradiated at 4 h and 5 h, corresponding to the stage when pronuclear formation was complete. The drastic change with pronuclear formation was found not only in radiosensitivity but also in the frequency of chromosome aberrations. The frequency of chromosome-type exchanges decreased drastically 2 h after insemination, and exchanges were barely observed at 5 h. The difference in radiosensitivity between male and female genomes also markedly changed with pronuclear formation, the chromosome aberration induction in the female genome being much higher than that in the male genome before accomplishment of pronuclear formation. The analysis of potentiation effects of 3-aminobenzamide and caffeine on the yield of X-ray-induced chromosome aberrations demonstrated that the increase of radiosensitivity and the decrease of chromosome-type exchange induction with pronuclear formation, may be closely correlated with alterations in chromatin configuration in the pronuclei and in repair capacity of fertilized eggs at the pre-DNA-synthetic stage. No evidence based on repair efficiency was found for the marked difference in radiosensitivity between male and female genomes during pronuclear formation.

Animals↗
PubMed1989

Comparison of the prejunctional beta-adrenoceptor stimulating actions of adrenaline and isoprenaline in the dog mesenteric vein.

1. The prejunctional beta-adrenoceptor stimulating actions of adrenaline and isoprenaline were compared by recording junction potentials from smooth muscle cells of the dog mesenteric vein. 2. The potency of adrenaline and isoprenaline on beta-adrenoceptors in the postjunctional membrane was estimated from hyperpolarization of the membrane in smooth muscle cells of the guinea-pig facial vein. In the presence of yohimbine, both agents hyperpolarized the membrane to a similar extent. 3. In the dog mesenteric vein, amplitude of the excitatory junction potential (e.j.p.) and slow depolarization was inhibited by adrenaline and potentiated by isoprenaline; the former but not the latter was accompanied by depolarization of the smooth muscle membrane. 4. In the presence of yohimbine, adrenaline inhibited the e.j.p. without depolarization of the smooth muscle membrane; the action was weaker than in the absence of yohimbine. The isoprenaline-induced potentiation of the e.j.p. was further enhanced by yohimbine. 5. It is concluded that adrenaline and isoprenaline have similar stimulating actions on postjunctional beta-adrenoceptors in the guinea-pig facial vein, but have different actions on prejunctional beta-adrenoceptors in the dog mesenteric vein; isoprenaline but not adrenaline stimulates this beta-adrenoceptor to facilitate the release of transmitter substances from perivascular noradrenergic nerves.

Adrenergic beta-Agonists↗
PubMed1989

Electrical and mechanical activity of rabbit prostate smooth muscles in response to nerve stimulation.

1. The rabbit prostate contains two smooth muscle bundles: one forms the capsule of the prostate and the other runs longitudinally in the outermost layer of the prostate. The former was contracted by exogenously applied noradrenaline (NA) and the latter by acetylcholine (ACh), and were therefore identified as NA-sensitive and ACh-sensitive muscles, respectively. 2. In the NA-sensitive muscle, exogenously applied NA, but not ACh, depolarized the smooth muscle membrane, and this action of NA was antagonized by prazosin but not by yohimbine. The membrane of the ACh-sensitive muscle was depolarized by ACh and hyperpolarized by NA. The former was antagonized by atropine and the latter by phentolamine. 3. In both bundles, electrical stimulation of intramural nerves elicited a biphasic junction potential: an excitatory junction potential (EJP) followed by an inhibitory junction potential (IJP). In the NA-sensitive muscle, the EJP was resistant to alpha-adrenoreceptor antagonists and sensitive to guanethidine, while the IJP was sensitive to apamin and resistant to alpha- or beta-adrenoreceptor antagonists or guanethidine. The EJP and IJP elicited in the ACh-sensitive muscle were inhibited by atropine and apamin, respectively, but both potentials were resistant to alpha- or beta-adrenoreceptor antagonists or guanethidine. 4. Transmural nerve stimulation elicited a twitch contraction in both muscle bundles, and the contractions in the NA-sensitive muscle were partially inhibited by prazosin and blocked completely by guanethidine. The contraction of the ACh-sensitive muscle was blocked by atropine. Contractions produced by exogenously applied NA and ACh were antagonized by prazosin and atropine, respectively. 5. It is concluded that in the rabbit prostate there are two smooth muscles bundles which are respectively contracted with associated depolarization by NA or ACh. The NA-sensitive muscle receives adrenergic excitatory and non-adrenergic non-cholinergic inhibitory innervation. The ACh-sensitive muscle receives cholinergic excitatory and non-adrenergic non-cholinergic inhibitory innervation.

Animals↗
PubMed1989

[Case report of periodontal disease with periodic neutropenia].

A case of periodic neutropenia with specific symptoms of gingiva and alveolar bone loss in primary dentition is reported. The patient was a boy, and it was followed between the ages of 3- and 9 years-old. At the period of neutropenia he was suffered from recurrent redness, swelling and bleeding of the gingiva, and also with cold-like symptoms with fever. Although the cause of these symptoms was not definite at first, even in medical exploration, we could diagnose this disease as periodic neutropenia by the process of dental therapy. By alveolar bone resorption, pocket formation and severe tooth mobility, the patient had lost more than half of his primary teeth at the end of 2 years after the initial examination. However throughout this period we motivated and instructed the patient and his mother how to brush his teeth. His oral hygiene was improved in the mixed and permanent dentition stages. Then there was no evidence of bone resorption around the teeth of the permanent dentition stage, but recurrent gingival symptoms are continuing now. The specific feature of this case is found in the gingival findings. There was no ulceration of the oral mucosa, but a bright red jelly-like appearance was found periodically in the area of the marginal and attached gingiva. The junction between the reddened attached gingiva and the alveolar mucosa was well-defined. The serial examination of peripheral blood in this case revealed the cycle of neutropenia as 16 to 21 days. During this examination, and at the almost time of neutropenia of this patient, hyperplasia of monocytes and lymphocytes occurred. In this situation there was no clinical signs except for gingival redness. However at other times, generally marked signs were recurrent. This may have occurred due to the lack of both neutrophils and monocytes. From the above results we think that periodic neutropenia may be diagnosed first in the dental clinic by the distinctive redness in the gingival area as one specific sign of this disease. We also think that plaque control procedures may retain the teeth.

Alveolar Bone Loss↗
PubMed1989

[Cognition for visual perception of a student apprentice of dental hygiene to the presence of a parent beside the dental chair for dental treatment].

With a view to finding out how the dental hygienist looks at and recognizes the changes in facial expression and behavior of a mother who is staying by her child just receiving dental care in the treating room, actions which the mother takes near her child were recorded and subjected to observation by a dental-hygienist apprentice. The eye movements of the apprentice were then recorded and analyzed, using the Visicon-Eye-Camera. The results obtained are as follows: 1. In all scenes of the test image, the subject closely observed the mother's face, the child's face and trunk and the dentist's face at a high frequency. 2. In all scenes of the test image, the subject tended to observe closely the mother's face in the former half of his observation and the child's face and the dentist's face in the latter half. 3. In a scene during which the mother looked anxious, the subject tended to look a longer time per observation. 4. In a scene during which there occurred only a change in the mother's expression, the subject frequently took the mother's face, the child's face or the dentist's face as his primary point of observation. 5. The scanning path of the subject was not influenced by a change in the mother's expression, but rather was influenced by the addition of new elements into the scene such as her grasping of the child's hands. 6. In case of the mother beginning to make a body movement, the subject frequently took the mother's face and her child's face as his primary point of observation. 7. The subject tended to make close observation of the dentist's face less frequently with more changes in the mother's behavior, suggesting his tacit cognition of the dentist being there. 8. The above results reveal that the dental hygienist is not visually influenced by the co-existence of a mother and her child just receiving dental care in the treating room if only she is looking at her child in a relaxed manner without any anxious expressions and attitudes.

Adult↗
PubMed1989

[Availability of intermittent chemotherapy by reservoir in liver metastasis of colo-rectal cancer].

From August 1986 to May 1989, in 18 cases of liver metastasis from colo-rectal cancer, intermittent chemotherapy was undergone by implantation reservoir in the subcutaneous. Intra-arterial infusion chemotherapy was under taken in 6 cases, and intra-portal vein chemotherapy in 12 cases. 5-FU 500 mg + MMC 10-6 mg was infused through implantable reservoir once every two weeks. CDDP and ADM were also infused in one case. Infusions averaged 12.4 times, and the most was 24 times in the group of intra-arterial infusion chemotherapy. In the group of intra-portal vein infusion chemotherapy, infusion averaged 12.4 times, with the highest at 35 times. In liver metastasis (H3), there is no significant difference between intra-arterial infusion chemotherapy and intra-portal vein infusion chemotherapy, revealing the cumulative survival rate. And the reservoir group compares with the 14 cases of hepatectomy and the 9 cases of systemic chemotherapy in cumulative survival rate. As a result, there was no significant difference between the group with the reservoir and the systemic chemotherapy group in H1 cases and H2 cases, revealing a median survival rate in these treatment groups. The median survival of reservoir group was 8.3 months, and that of the hepatectomy group was 20.6 months in H2 cases. In the H3 cases, the median survival of the reservoir group was 9.6 months, and that of the systemic chemotherapy group was 10.3 months. Reservoir was implanted in three cases to prevent recurrence after hepatectomy. As a result, two of three cases have survived for 20 months and 10 months, respectively.

Adult↗