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Biomedical subjects

K Taga

Publications and source records attributed to K Taga.

At least 73 records · Page 4Linked to original sources
PubMed1990

[The effect of DREZ (dorsal root entry zone) lesions on intractable pain in patients with spinal cord injury].

Some patients with spinal cord injury complain of a severe intractable pain. This intractable pain places new hurdles on the road to return to the ordinary daily life in these patients. The effective therapy for the intractable pain has not been established. Dorsal root entry zone (DREZ) lesion was originally reported by Nashold et al to alleviate deafferented pain syndrome. Three male and one female patients with intractable pain following spinal cord injury were treated with DREZ-lesions. One month after operation, all 4 patients obtained good pain relief. However, at a follow-up period till February 1989 (ranging 11 months from 2 years and 6 months), 2 patients had subjective pain relief. When other therapies on intractable pain following spinal cord trauma are not effective, the DREZ-lesion might be considered.

Adult↗
PubMed1989

Changes in surface capacitance and conductance parallel to phospholipid membranes associated with phase transition: effects of halothane.

The effects of phase transition on the surface capacitance and conductance parallel to dipalmitoyl- (DPPC) and dimyristoyl-phosphatidylcholine (DMPC) membranes were studied by impedance dispersion. The phospholipid aggregates were embedded into pores of a polycarbonate filter and the impedance dispersions were measured at a frequency range from 30 Hz to 1.0 MHz. When the frequency was below 120 kHz, the capacitance showed a peak at the pretransition temperature and a steep rise at the main-transition temperature. In this system, the observed capacitance consists of frequency-dependent and -independent parts. The frequency-dependent part is a surface phenomenon and arises from the lateral motion of counterions at the membrane/water interface. The frequency-independent part represents mainly the properties of the bulk lipid phase. Addition of halothane decreased the total capacitance of the DPPC aggregates at the low frequency range to 1/2 to 1/8 of the control depending upon the temperature. The surface component was solely responsible for this capacitance decrease, because the non-surface component was slightly increased instead. The data suggest that halothane inhibited the lateral ionic flow parallel to the interface.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1989

Prostaglandin E1 modifies porcine cerebral arterial tone through cyclooxygenase related eicosanoid(s) release.

The effects of prostaglandin E1 (PGE1) on porcine cerebral arteries were studied in the absence and presence of cyclooxygenase inhibitors, 5 x 10(-6) M indomethacin or 10(-4) M aspirin. In preparations placed at a resting tension, 3 x 10(-9) to 10(-6) M PGE1 caused dose-dependent contractions. In prostaglandin F2 alpha (PGF2 alpha)- contracted preparations, low concentrations of 10(-9) and 3 x 10(-9) M PGE1 did not modify arterial tone and higher concentrations of 10(-8) to 10(-6) M PGE1 further increased the arterial tone in all preparations tested. In contrast, in the presence of the cyclooxygenase inhibitors, low concentration of 10(-9) and 3 x 10(-9) M PGE1 markedly decreased the arterial tone induced by PGF2 alpha and higher dose of 10(-8) to 10(-6) M PGE1 increased the arterial tone in 15 of 18 preparations (83%). These findings suggest that PGE1 modifies porcine cerebral vascular tone at least partly through cyclooxygenase-related eicosanoid(s) production.

Animals↗
PubMed1989

Survival after sudden cardiac arrest in hospital.

Although there are many reports on sudden cardiac arrest occurring outside the hospital, little is known about the precise prognostic factors that determine the outcome after cardiopulmonary resuscitation. Clinical information before and immediately after sudden cardiac arrest is frequently incomplete because the event occurs outside the hospital. We studied 90 consecutive patients with sudden and unexpected cardiac arrest who were resuscitated in the general ward of our hospital. Twenty-five (28%) were discharged from the hospital. Multivariate analysis revealed that the promptness of initiation of CPR, age, severity of cardiac dysfunction, time and the type of arrhythmia are of significance in relation to survival. To evaluate long-term survival after hospital cardiac arrest, we analyzed long-term follow-up data accumulated during a 16 year period. In the group of 25 patients in our study, there have been a total of 10 deaths (40%). Five of the 10 deaths resulted from recurrent cardiac arrest and 1 was a noncardiac death. There was a high rate of recurrence of cardiac arrest in the first year following resuscitation, especially among the cardiomyopathy patients.

Adolescent↗
PubMed1989

[Two-dimensional echocardiographic and left ventriculographic evaluations of left ventricular diverticula].

Twenty cases of left ventricular diverticula were gleaned from 4,300 consecutive angiocardiographic records (13 males and seven females whose age ranged from 17 to 78 years with a mean of 52 +/- 16 years). Their findings were compared with those of 16 patients with left ventricular aneurysms due to myocardial infarction. In only one patient was a diverticulum first detected by two-dimensional echocardiography before left ventriculography was performed. None of the patient had an associated midline thoracoabdominal defect. Five patients had premature ventricular beats, two of whom had ventricular tachycardia. Three patients complicated mitral valve prolapse and three atrial septal defect. Of the 20 patients, four each had two diverticula, as opposed to 16 others who each had a single diverticulum. The diameter of the diverticula ranged from eight to 70 mm. The sites of 14 diverticula were along the inferior wall; five in the anterior wall; four in the apex. Morphologically 15 diverticula were bulky outpouchings, six were tongue-like, and three hammocking. All diverticula exceeding 15 mm in diameter and originated near the mitral ring could always be detected in the short-axis view of two-dimensional echocardiography. However, those originating in the apex or of a tongue-like configuration could rarely by detected. Comparative two-dimensional echocardiographic analyses of 16 diverticula, 16 left ventricular aneurysms, and 16 normal left ventricular walls disclosed that the left ventricular aneurysmal wall had a higher echo intensity, but the diverticula had the same wall echo intensity as the normal left ventricular wall. Left ventricular end-diastolic wall thickness in an aneurysm (7.6 +/- 1.5 mm) was lower (p less than 0.01) than the normal left ventricular wall (11.1 +/- 1.3 mm), but it did not differ from the normal left ventricular wall in any case of diverticulum (10.2 +/- 1.5 mm). The percent wall thickening ratio in aneurysms (-3.6 +/- 10.7%) was lower (p less than 0.01) than the normal left ventricular wall (39.8 +/- 10.9%), but it did not differ from the normal left ventricular wall in diverticula (45.8 +/- 16.6%). Regional fractional shortening in the diverticula (41.3 +/- 9.2%) did not differ from that in the normal left ventricular wall (34.5 +/- 5.2%). In conclusion, a small diverticulum without a midline thoracoabdominal defect is not rare, and two-dimensional echocardiography is the diagnostic method of choice in many cases based on the echo features described above.

Adolescent↗
PubMed1988

[Effects of halothane and isoflurane on the canine duodenal paraneurons].

Administration of amino acid solution (50 mM tryptophane and phenylalanine in saline) into the canine duodenum is known to cause an increase in pancreatic secretion. This response is mediated by the excitation of duodenal endocrine cells, paraneurons, which release cholecystokinin (CCK) into the systemic circulation in response to intraluminal amino acid stimuli. Pancreatic secretory cells are then evoked by the CCK in the blood to secrete the juice into the duodenum. The authors investigated the effects of two general anesthetics, halothane and isoflurane, on this response. Nine mongrel dogs were subjected to this study. Each dog underwent laparotomy under nitrous oxide (75%)-oxygen (25%) anesthesia with pancuronium (GO-Pb). The duodenal loop was exposed and two polyethylene cannulae (18Fr) were introduced into the loop. Proximal cannula was for the administration of the amino acid solution into the loop, and distal one was for drainage of the solution. The pancreatic duct was inserted with a polyethylene catheter, through which pancreatic juice was collected and measured for the volume and protein output by spectrophotometry. After these surgical procedures, the pancreatic secretory response to intraluminal amino acid stimuli was examined under GO-Pb (Control). Then halothane (1.0%) (Group 1, four dogs) or isoflurane (2.0%) (Group 2, five dogs) was administered for 30 min and the same response was tested. The pancreatic secretory response to intraluminal amino acid stimulus was suppressed by the surgical concentrations of both halothane (1.0%) and isoflurane (2.0%). Neither halothane nor isoflurane suppressed the pancreatic secretory response evoked by intravenous CCK infusion (10 Ivy Dog Units.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Effects of pentobarbital and ketamine on brain injury-induced anti-ischemic activity.

Survival rates following incomplete brain ischemia induced during pentobarbital anesthesia were significantly higher in mice with a minor brain injury, inflicted one week before, than in those given a sham operation. Improvement of the survival rates in mice with brain injury, however, became insignificant when brain ischemia was imposed during ketamine anesthesia, suggesting that the actions of certain factors or protective mechanisms against brain ischemia, developed by brain injury, are antagonized by ketamine and/or potentiated by barbiturate anesthesia.

Anesthesia↗
PubMed1986

Phenotypic and functional characteristics of active suppressor cells against IFN-gamma production in PHA-stimulated cord blood lymphocytes.

Cord blood mononuclear cells (MNC) were defective in their ability to produce interferon-gamma (IFN-gamma) on stimulation with phytohemagglutinin (PHA) or recombinant interleukin 2, whereas cord MNC could induce comparable amounts of IFN-gamma with adult controls on stimulation with a streptococcal preparation, OK-432. Moreover, irradiation of cord MNC with 1,500 rad before PHA stimulation could restore the IFN-gamma production. Kinetic studies indicated that such augmentation of IFN-gamma production by irradiation was evident when cord MNC were irradiated before or by 12 hr of PHA-stimulated culture. But irradiation after 18 hr or more of PHA stimulation did not exert any significant augmentation on IFN-gamma production by cord MNC. It seemed most likely that the ability of IFN-gamma production is already mature at birth, but radiosensitive suppressor effectors on IFN-gamma production are activated within cord MNC at an early stage of PHA stimulation, resulting in poor IFN-gamma production by cord MNC. PHA-induced IFN-gamma production by OKT3+, OKT4+, and OKT8- cord cells were markedly enhanced by irradiation with 1,500 rad before the culture. Coculture experiments disclosed that cord OKT4+ cells, but not OKT4- cells, when prestimulated with PHA for 24 hr, exerted active suppression on PHA-induced IFN-gamma production by adult MNC in a dose-dependent manner. These results suggested that radiosensitive suppressor effectors on IFN-gamma production were induced within the OKT4+ T cell subset of cord MNC on PHA stimulation.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1986

Effects of a thromboxane synthetase inhibitor (OKY-046) and a lipoxygenase inhibitor (AA-861) on bronchial responsiveness to acetylcholine in asthmatic subjects.

The effect of a selective thromboxane synthetase inhibitor, OKY-046, and a selective 5-lipoxygenase inhibitor, AA-861, on bronchial responsiveness to acetylcholine was studied in 23 asthmatic subjects. The provocative concentration of acetylcholine producing a 20% fall in forced expiratory volume in one second (PC20 FEV1) was measured before and after oral administration of OKY-046 (3000 mg over four days) and AA-861 (1100 mg over four days) and inhalation of OKY-046 (30 mg) in 10, 10, and nine asthmatic subjects respectively. Baseline values of FEV1 and forced vital capacity (FVC) were not altered by oral OKY-046, oral AA-861, or inhaled OKY-046. The geometric mean value of PC20 FEV1 increased significantly from 0.55 to 2.24 mg/ml after oral OKY-046, but was unchanged after inhalation of OKY-046 and after oral administration of AA-861. These results suggest that thromboxane A2 may play a part in bronchial hyperresponsiveness to acetylcholine.

Acetylcholine↗
PubMed1986

Malignant clonal expansion of large granular lymphocytes with a Leu-11+, Leu-7- surface phenotype: in vitro responsiveness of malignant cells to recombinant human interleukin 2.

A 14-year-old Japanese female with neutropenia showed malignant proliferation of the large granular lymphocytes (LGLs). These LGLs were E rosette+ and Fc(IgG) receptor+ and therefore are referred to as T gamma lymphocytes. They were also Leu-11+ and OKT11+; however, they were clearly negative for Leu-7, OKT3, OKT8, OKM1, and HNK-1 antigens as well as for terminal deoxynucleotidyl transferase activity. Karyotype analysis revealed 47, XXX. The LGLs showed no rearrangement of T cell receptor C beta genes. The natural killer (NK) cell activity against K562 target cells was low, but was significantly augmented after stimulation by recombinant human interleukin 2 (IL 2) in contrast to minimal NK boosting by recombinant human gamma-interferon (gamma-IFN). Such a unique responsive ability to lymphokines was quite similar to that noted in fetal and cord blood cells. These LGLs also demonstrated a considerable increase in antibody-dependent cell-mediated cytotoxicity (ADCC) and lymphokine-activated killer (LAK) activity after a short incubation with IL 2. Although in a resting stage they showed no IL 2 receptor expression as examined by anti-Tac antibody, Tac antigen appeared after IL 2 treatment followed by a marked increase in 3H-thymidine incorporation and a remarkable production of gamma-IFN. To investigate the mechanism of neutropenia, in vitro IL 2-stimulated coculture studies of these cells with normal bone marrow cells were performed. Colony formation of myeloid progenitors (CFU-C) was significantly suppressed. In addition, the conditioned medium from IL 2-stimulated LGLs indicated a remarkable suppression of CFU-C. These results suggest that these LGLs with a Leu-11+, Leu-7- surface phenotype might belong to a unique subset of pre-NK cells that are functionally and phenotypically similar to those represented at any early stage of human ontogeny and that they strongly express Tac antigen under the influence of IL 2 administration, followed by remarkable cell proliferation and gamma-IFN production.

Adolescent↗
PubMed1986

Monoclonal antibody which has the neutralizing activities for human IL-2.

Six monoclonal antibodies against recombinant human interleukin-2 (IL-2) were successfully prepared by fusing NS-1 with spleen cells of BALB/c mice immunized with human recombinant IL-2. The specificities of these monoclonal antibodies were confirmed. By enzyme linked immunosorbent assay (ELISA) method, the antibody concentrations of each ascitic fluid obtained from BALB/c-nu/nu transplanted with the established hybridoma clones were varied for 10(3) to 10(5) depending on the clone. By SDS-PAGE analysis with immunoprecipitates formed between monoclonal antibodies and recombinant human IL-2, all monoclonal antibodies reacted unequivocally with recombinant human IL-2. Two monoclonal antibodies (designated as KNT-1 and KNT-2) out of six established clones reacted with natural human IL-2 molecule obtained from cultured human peripheral blood lymphocytes (PBL) stimulated with PHA-P and TPA. KNT-1 and KNT-2 monoclonal antibodies have inhibitory effects on the proliferative response of natural killer (NK-7) cell (one of the IL-2 dependent cultured cell lines) elicited by recombinant, natural human, or natural rat IL-2. Monoclonal antibody, KNT-1, inhibited activities of both recombinant or natural human IL-2, but did not neutralize activities of IL-2, derived either from murine EL-4 or from rat spleen cells. Another monoclonal antibody, KNT-2, had neutralizing activity for either recombinant or natural human IL-2 and eliminated the activity of rat-derived IL-2, but did not interfere with the activity of murine IL-2. The remaining four monoclonal antibodies (designated as KNT-3, -4, -5 and -6) did not affect the proliferative response of NK-7 cells elicited by natural human, rat and murine IL-2. These observations indicate that functional portion(s) of IL-2 molecules from different species have somewhat different structures.

Animals↗
PubMed1985

Some evidence for the in vivo functional activation of suppressor T cells in asymptomatic patients with hemophilia A receiving Factor VIII concentrates.

Of 14 asymptomatic hemophilia A patients receiving factor VIII concentrates, 11 severe hemophilia patients had an inverted T-helper/suppressor ratio but 3 moderate patients had a normal ratio. Most hemophilia patients showed poor lymphocyte proliferative responses to mitogens and diminished in vitro immunoglobulin-producing ability of lymphocytes. One important finding was that most patients were found to have increased numbers of Ia-like antigen-positive suppressor T cells, suggesting that circulation activated suppressor T cells. In addition, OKT8+ suppressor T cells from severe hemophilia patients showed strong suppressor activity on B-cell differentiation in a Nocardia delipidated cell mitogen-driven system, whereas those from normal age-matched controls showed no suppressor function. These results suggested that suppressor T cells in hemophilia patients treated with factors might be already activated in vivo by undetermined mechanisms, implying the presence of a peculiar immunoregulatory status in this disease.

Adolescent↗