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Biomedical subjects

K Seki

Publications and source records attributed to K Seki.

At least 127 records · Page 7Linked to original sources
PubMed1998

Analysis of water in Autonomous Biological Systems (ABS) samples.

Several soluble components, peptidase and amino acids, and carbon isotopic ratio in the water retrieved from flight experiments of Autonomous Biological Systems (ABS) as well as ground control samples are analyzed to interpret the condition, dynamics, material balance of the ABS ecosystems. Organic carbons in flight samples were found to be more abundant compared with the control ones, which suggested the uniform ecosystems in low gravity might easily dissolve more soluble components. The Mir-1997 flight sample showed higher C/N ratio probably because of the dissolution of carbon-rich plant materials.

Alkaline Phosphatase↗
PubMed1998

Microorganisms and plant of Autonomous Biological Systems (ABS) samples.

Distribution of microorganisms and cellular structure of an Autonomous Biological Systems (ABS) were studied with a special attention to the effect of space environments. Viable cell densities measured by the direct fluorescence microscopic method were in the order of 10(5) cells/ml for fractions 1 (upper suspension) and 2 (lower suspension), and 10(6) cells/ml for fraction 3 (sediments). These values were 10 to 100 times larger than the values obtained by the classical colony forming unit method. No difference between flight and ground samples was observed in the vertical distribution of viable microorganisms when fractionation and analysis were carried out after recovery. Intracellular distribution of chloroplasts in higher green plants, Ceratophyllum demersum, of flight samples was disturbed after 10 days of flight (24hrs/day light on). After 4 months of flight (Mir/STS-79/81) with 24 hrs light on, Ceratophyllum demersum was completely disintegrated. On the other hand, in the second 4-months-flight experiment with 16 hrs/day light on, Ceratophyllum demersum was only slightly deteriorated.

Aquaculture↗
PubMed1998

[Results of clinical study with epirubicin hydrochloride injectable solution in hepatoma].

A 10-center cooperative clinical study with a new formulation of epirubicin hydrochloride injectable solution (Epirubicin-RTU) was conducted in patients with hepatocellular carcinoma. Epirubicin-RTU 60 mg/m2 was injected into the hepatic artery and a three-week drug-free interval followed. Of 15 patients with hepatocellular carcinoma registered in this study, 14 patients were eligible, and they all completed the entire course. The objective was to investigate the safety of treatment with Epirubicin-RTU in 14 eligible patients. The adverse drug reactions frequently observed in these 14 eligible cases were leukopenia, neutropenia, thrombocytopenia, alopecia, and fever. They were all reversible and tolerable. With these results. Epirubicin-RTU was considered to be a safe pharmaceutical product to inject into the hepatic artery.

Adult↗
PubMed1997

Effects of pyramidal tract stimulation on forelimb flexor motoneurons during fictive locomotion in cats.

To investigate spinal mechanisms of control of locomotion by the pyramidal system, we made intracellular recording from forelimb flexor motoneurons, and analyzed excitatory postsynaptic potentials (EPSPs) evoked by stimulation of the medullary pyramid during forelimb fictive locomotion in immobilized, decerebrate cats. We observed that (1) pyramidal stimulation evoked disynaptic EPSPs, (2) which were much bigger in the locomotor state than in the resting state, and that (3) the pyramidal EPSPs were rhythmically modulated, so that the facilitation occurred in the flexor-active phase. Last-order neurons mediating pyramidal effects presumably receive rhythmic input from the spinal locomotor network.

Animals↗
PubMed1997

3.5% hypertonic saline produces sympathetic activation in hemorrhaged rabbits.

The neural mechanisms for pressor effects after hypertonic saline infusion are still unclear. Using direct measurement of the renal sympathetic nerve activity (RNA), we tested the hypothesis that the autonomic nervous system is involved in an acute blood pressure elevation produced by hypertonic saline (HTS) in anesthetized rabbits subjected to hemorrhage. Twenty urethane-anesthetized rabbits were ventilated mechanically after a tracheostomy and paralyzed with gallamine triethiodide. Heart rate (HR), mean blood pressure (MBP) and central venous pressure (CVP) were measured simultaneously with RNA. The animals were divided into the following four groups: (1) animals with intact baroreceptors that received HTS (intact HTS group, N = 5); (2) those with intact baroreceptors that received normal saline (intact NS group, N = 5); (3) those that underwent selective cervical vagotomy (vagotomy group, N = 5); (4) those with sino-aortic denervation (SAD group, N = 5). The last two groups were given HTS only. After inducing hemorrhagic hypotension to 40 mmHg over 10 min, 3.5% HTS at half the volume of shed blood was infused over approximately 120 s. In the intact HTS group, sympathetic activation, associated with tachycardia and pressor effects, developed. This enhancement of RNA was followed by a return to the pre-infusion level, but the increased blood pressure and tachycardia lasted until the end of the experiment. These levels of MBP and HR were significantly higher than those of the intact NS group. In the vagotomized animals, HTS resuscitation also increased RNA and systemic blood pressure. In contrast, in the SAD group, neither sympathetic activation nor an early phase increase in systemic blood pressure occurred. These results indicate that in hemorrhaged rabbits, 3.5% HTS produces sympathetic activation along with an acute pressor effect and that this is likely to be mediated through the sino-aortic nerves, possibly the peripheral chemoreceptors, but not through the vagal nerves.

Animals↗
PubMed1997

Cutaneous reflex activity of the cat forelimb during fictive locomotion.

To investigate mechanisms of rhythmic modulation of cutaneous reflex by the central pattern generator for locomotion, we made intracellular recordings from elbow flexor motoneurons, biceps brachii (Bi) and brachialis (Br), and quantitatively analyzed excitatory postsynaptic potentials (EPSPs) evoked by stimulation of superficial radial (SR) nerves during forelimb fictive locomotion, which was evoked in immobilized, decerebrate cats with the low thoracic spinal cord transected. We found that (1) in both Br and Bi, SR stimulation evoked trisynaptic EPSPs (segmental latencies were 2.10 +/- 0.39 ms for Br and 2.07 +/- 0.93 ms for Bi), (2) the SR-EPSPs of Br and Bi were rhythmically modulated with a similar pattern; the maximal and minimal EPSPs appeared in the flexor and extensor phase, respectively, (3) however, there were differences as follows. In the control state where fictive locomotion was absent, the mean amplitude of SR-EPSPs of Br (4.65 +/- 2.76 mV, n = 14) was much larger than that of Bi (1.25 +/- 1.22 mV, n = 10). During fictive locomotion, the maximum amplitude of SR-EPSPs of Br was 5.63 +/- 1.79 mV (n = 18), and the minimum was 3.82 +/- 1.69 mV (n = 18); that is, the maximum during fictive locomotion was larger or smaller than that of the control, while the minimal were always smaller. In contrast, SR-EPSPs of Bi were modulated over the control level; the maximum was 3.97 +/- 1.71 mV (n = 16) and the minimum was 2.24 +/- 1.11 mV (n = 16), both the maximum and the minimum during locomotion being larger than that of the control. These results may suggest that two mechanisms are involved in the rhythmic modulation, first, cyclic facilitation in the flexor phase, and secondly, cyclic inhibition in the extensor phase. The former was involved in both cases of Bi and Br motoneurons, while the latter would be involved only in the case of Br motoneurons.

Animals↗
PubMed1997

Distinct processes in line bisection according to severity of left unilateral spatial neglect.

We investigated the line bisection performances in 24 patients with left unilateral spatial neglect. They bisected lines of two lengths in three positions relative to the sagittal midplane of the body. The results showed that in the mild or moderate neglect patients, length and spatial locations of the lines affected the placement of the subjective midpoint. In the severe neglect patients, however, length had little effect on their performances, and location of the right endpoint in the egocentric space mainly determined the subjective midpoint. The line bisection process of the severe neglect patients was not only quantitatively but also qualitatively different from that of the mild or moderate cases.

Adult↗
PubMed1997

Endometrial carcinoma in 45,X Turner's syndrome without hormone replacement therapy.

An endometrial carcinoma developing in a patient with pure Turner's syndrome was described. The patient showed typical Turner's phenotype and analysis of karyotype revealed only 45,X. Secondary sexual development had been seen until age 20 and she had no history of hormone replacement therapy (HRT). The enlarged uterus and normal appearance of bilateral ovaries were detected at laparotomy. A well-differentiated adenocarcinoma of the endometrium and a graafian follicle of the left ovary were histologically confirmed. This seems to be the first report of the occurrence of endometrial carcinoma in possibly pure Turner's syndrome without HRT.

Adult↗
PubMed1997

Effect of aortic impedance on preload-afterload mismatch in canine hearts in situ.

The aim was to examine the influence of the independent increase of aortic wall characteristics from vascular resistance on global left ventricular (LV) function in intact hearts. In 11 anesthetized dogs, aortic stiffness was increased by a constriction of the thoracic aorta using a stiff tube, and then, in nine dogs, total systemic resistance (TSR) was increased by an infusion of angiotensin II. During the above procedures, aortic input impedance and LV dimension were measured. Aortic input impedance spectra revealed the steady increase in the moduli at high frequencies by aortic constriction, indicating the increase in aortic stiffness. At the stage of increased aortic characteristic impedance (Zc) (134% of control) without a change in TSR, both LV end-diastolic diameter (LVEDD, 99%, p < 0.01 and stroke volume (SV, 95%, p < 0.01) decreased significantly without a change in LV end-systolic diameter (LVESD). During the increase in TSR produced by angiotensin II (128% of control) without a change in Zc, LVEDD tended to increase and LVESD significantly increased (103%, p < 0.01) associated with a decrease in SV (94%, p < 0.01). LV systolic mean wall stress was increased by angiotensin II (118%, p < 0.01), whereas it was unchanged by aortic constriction. In conclusion, the isolated increase in aortic stiffness without a change in TSR was associated with a reduction in LV preload and SV.

Animals↗
PubMed1997

Efficacy of combination therapy of interferon-alpha with ursodeoxycholic acid in chronic hepatitis C: a randomized controlled clinical trial.

The efficacy of interferon-alpha therapy in the treatment of chronic hepatitis C is still limited. A combination therapy of interferon-alpha with ursodeoxycholic acid (UDCA) was tested for its efficacy in the treatment of chronic hepatitis C by a randomized controlled study. Eighty consecutive Japanese patients with chronic hepatitis C were randomly divided into two groups: one group was treated with interferon-alpha (group A, n = 40) and the other with a combination of interferon-alpha and UDCA (group B, n = 40). In both groups, human interferon-alpha (6 million units per day) was intramuscularly injected daily for 2 weeks and then three times a week for 22 weeks: this 24-week period was followed by 24 weeks of observation. In group B, UDCA was also administered, daily at a dose of 600 mg orally, from the beginning of the interferon therapy and administration was continued for 48 weeks. The rates for ALT normalization and clearance of hepatitis C virus (HCV) viremia at the end of the 24-week interferon therapy were similar for groups A and B (58% vs 60% and 55% vs 48%, respectively). At the end of the 24-week follow-up, the sustained normalization rates for ALT levels for the two groups were not different (35% vs 43%), while the rate of clearance was higher in group B (40%) than in group A (23%), but the difference was not significant (P = 0.14). The sustained complete response, i.e., HCV RNA negativity at the end of the follow-up, as well as the maintenance of ALT normalization during the follow-up period, was more frequent in group B (38%) than in group A (18%) although the difference was not significant (P = 0.08). The rate of HCV reactivation after interferon was discontinued was significantly lower in group B (16%) than in group A (59%) (P < 0.01). Although this combination therapy did not lead to a sufficiently sustained complete response, it could serve as adjuvant antiviral therapy when a suitable dosage and administration period are determined.

Administration, Oral↗
PubMed1997

Right hepatectomy for pyogenic liver abscesses with true multiloculation.

We report the case of 61-year-old woman with cryptogenic liver abscesses who had been profoundly ill with severe upper abdominal pain, impaired consciousness, prostration, continuous high fever secondary to sepsis, and thrombocytopenia (platelets, 1-5 x 10(4)/mm3) since admission. Ultrasonograms and computed tomograms revealed two separate multiloculated lesions in the right lobe of the liver, consistent with the liver abscesses. Immediately after diagnosis, percutaneous abscess drainage was performed under ultrasonographic guidance; however, only a small amount of pus was drained, prompting continuous irrigation of the abscess cavity. Four days later, transcatheter hepatic arterial infusion of antibiotics was attempted. However, the abscesses had enlarged and her general condition had worsened. On hospital day 8, she underwent right hepatectomy because the multiloculated lesions were refractory to drainage. The operation was successful in terms of hepatectomy, although she continued to suffer from sepsis, secondary right subphrenic abscess formation, and prolonged thrombocytopenia with associated coagulation disorders for two months. Examination of multiple cross sections of the resected specimen disclosed that the lesions consisted of aggregations of multiple small locules. There was no communication between the locules and there were true septations, rather than multiloculated lesions with pseudoseptations. The patient has been well for 2 years without recurrent abscess of the liver or any infectious disease.

Drainage↗
PubMed1997

Dissociated neglect for objective and subjective sizes.

We examined the effect of line length and viewing distance on the line bisection performance in near space in five patients with left unilateral spatial neglect following right parietal lesions. A line bisection task by fixation was devised to avoid the influence of manual responses. The rightward deviation measured in visual angle increased linearly as a function of the visual angle of lines 150 mm or more long. This linearity, however, did not hold for lines of 100 mm or less. The deviation measured in length was nearly constant for each of these short lengths, even when the visual angle was varied at different viewing distances. The patients therefore discriminated the objective lengths of the short lines. For small objects, neglect patients may distribute attention mainly on the coordinates scaled for objective size.

Aged↗
PubMed1997

Overlap of Guillain-Barre syndrome and Bickerstaff's brainstem encephalitis.

The nosological relationship between Bickerstaff s brainstem encephalitis (BBE) and Guillain-Barre syndrome (GBS) has yet to be clarified. We report results of the autopsy of a patient for whom overlapping BBE and GBS was diagnosed clinically. This and similar cases support the original authors' hypothesis that BBE is closely related to GBS.

Aged↗
PubMed1997

Epithelioid angiosarcoma of bone.

Angiosarcoma of bone is a rare, high-grade sarcoma of vascular origin. This article describes an epithelioid angiosarcoma in the humerus of a 48-year-old man. A multilocular osteolytic lesion with undefined margins and destroyed cortical and medullary bone, associated with a large soft tissue mass was demonstrated radiologically in the proximal metaphysis of the right humerus. The tumor, resected by amputation, was composed mostly of proliferating malignant cells with an epithelioid morphology. It had a predominantly sheet-like growth pattern, and an occasional pseudoglandular or alveolar arrangement, mimicking an adenocarcinoma. The dilated anastomotic vascular spaces lined by epithelioid endothelial cells and the intracytoplasmic lumina/vacuoles that sometimes contained erythrocytes suggested focal endothelial differentiation. On immunohistochemical investigation, many neoplastic cells expressed cytokeratin and endothelial markers: factor-VIII related antigen, CD31, and UEA-I. The ultrastructure of the tumor was consistent with that of an angiosarcoma. Our patient died of disease shortly after the diagnosis, implying an aggressive clinical course. Awareness of the existence of skeletal epithelioid angiosarcoma, combined with the identification of intracytoplasmic lumina, or at least small vasoformative foci, and immunohistochemical positivity for endothelial markers provide the best guide for distinguishing this tumor from metastatic carcinomas.

Biomarkers, Tumor↗
PubMed1997

Selective depletion of neutrophils by a monoclonal antibody, RP-3, suppresses dextran sulphate sodium-induced colitis in rats.

Administration of dextran sulphate sodium to animals induces acute colitis characterized by infiltration of large numbers of neutrophils into the colonic mucosa, which histologically resembles human active ulcerative colitis. It has been reported that neutrophils and the reactive oxygen metabolites produced by them are involved in the progress of ulcerative colitis. This study was intended to clarify their roles by using this animal model. First, possible sources and species of reactive oxygen metabolites were determined using luminol-dependent chemiluminescence with addition of enzyme inhibitors and reactive oxygen metabolite scavengers. Next, to examine whether neutrophils and hypochlorous acid derived from them contribute to tissue injury, we administered RP-3, a monoclonal antibody capable of selectively depleting neutrophils, and taurine, a hypochlorous acid scavenger, to rats treated with dextran sulphate sodium. Addition of azide, taurine, catalase, superoxide dismutase and dimethyl sulphoxide into colonic mucosal scrapings significantly inhibited chemiluminescence production, but allopurinol and indomethacin had no effects. These results suggest that excessive hypochlorous acid, hydrogen peroxide, superoxide anion and hydroxyl radical are generated by the inflamed colonic mucosa. Intraperitoneal injections of RP-3 significantly suppressed bleeding, tissue myeloperoxidase activity, chemiluminescence production and erosion formation. On the other hand, administration of taurine tended to inhibit bleeding and erosion formation to some extent, although it could not significantly suppress them. These data suggest that neutrophils play an important role in the development of this colitis and that hypochlorous acid might be one of the causes of tissue injury induced by neutrophils.

Animals↗
PubMed1997

Recombinant interferon-alpha-2a for treatment of chronic hepatitis C: results of a multicenter randomized controlled dose study.

To compare the efficacy of low and relatively high dosages of recombinant interferon (IFN)-alpha-2a in Japanese patients with chronic hepatitis C, as well as to characterize the type of patients who will respond well to a low-dosage treatment, 88 patients with histologically proven chronic hepatitis C were randomly assigned to two treatment groups; one treated with IFN-alpha-2a 6 MU daily for 2 weeks followed by 6 MU three times weekly for 22 weeks (6-MU group), and another given the same initial treatment followed by 3 MU three times weekly for 22 weeks (3-MU group). The rate of sustained normalization of ALT 6 months after the cessation of treatment was 33% in the 3-MU group and 40% in the 6-MU group (p = 0.64). In addition, there was no difference in elimination of serum HCV-RNA 6 months after the cessation of treatment between the 3-MU group (26%) and 6-MU group (29%). Multivariate stepwise regression analysis revealed that serum HCV-RNA level (p = 0.0035) and platelet count (p = 0.0009) were independent variables useful in predicting a sustained response of ALT. The sustained response rate of ALT in patients with a serum HCV-RNA level less than 10(5) copies/ml and serum platelet level above 15 x 10(4)/microliter was 71%, whereas that in patients with a serum HCV-RNA level above 10(5) copies/ml and serum platelet level less than 15 x 10(4)/microliter was 12%. These results indicate that a high rate of sustained response to IFN therapy can be expected in chronic hepatitis C patients with a low serum level of HCV-RNA and a high level of platelets, even if treated with a low dose of IFN.

Antiviral Agents↗