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Biomedical subjects

H Sakurai

Publications and source records attributed to H Sakurai.

At least 523 records · Page 29Linked to original sources
PubMed1987

Modulator effect of Toxoplasma lysate antigen in mice experimentally infected with Plasmodium berghei.

Normal mice were pretreated twice at an interval of 2 weeks with an emulsion of TLA (Toxoplasma lysate antigen), PLA (Plasmodium lysate antigen) or both in LMO (light mineral oil) or with a combination of the emulsion and Obioactin or Tp-LKs (Toxoplasma lymphokines) as an immunopotentiator. They were then given Obioactin or Tp-LKs 3 and 25 days after the first treatment and were further given parasitized erythrocytes with 1 X 10(2)-10(4) P. berghei 2 weeks after the second treatment. Thirty (3/10, number of survival/number of examined) per cent of mice treated with TLA, 50 (5/10)% of those treated with a combination of TLA and Tp-LKs and 60 (6/10)% of those treated with a combination of TLA and Obioactin survived as long as 20 days postinfection while none of untreated controls survived more than 15 days postinfection. Only 18.2 (2/11)% of mice treated with PLA or TLA + PLA survived and 20 (2/10), 18.2 (2/11) and 60 (6/10)% of those treated with TLA + Obioactin, PLA + Obioactin or TLA + PLA + Obioactin survived throughout the experiment, respectively while none of controls survived more than 13 days postinfection. Five mice of each group were killed right before infection, and 5, 10 and 15 days postinfection. In mice treated with TLA + Obioactin, more macrophage phagocytosis and macrophage migration inhibition induced by sensitized T-cells were observed than in those treated otherwise. No appreciable differences were noted according to the method of treatment in blood examination values. Cross immunities between Toxoplasma and Plasmodium antigens were tested by counter-immunoelectrophoresis and indirect fluorescent antibody technique. By using counter-immunoelectrophoresis, a specific precipitin line was observed between TLA and anti-PLA which was absorbed by mouse erythrocytes, leucocytes and liver powder. By the indirect fluorescent antibody technique, anti-Plasmodium IgM and IgG titers were detected in sera from mice treated with TLA or TLA-Obioactin before infection.

Adjuvants, Immunologic↗
PubMed1987

With time changes of T-lymphocytes after Babesia infection in mice pretreated with Toxoplasma lysate antigen.

Adult female mice of the ICR/JCL strain were injected intraperitoneally with an emulsion of Toxoplasma lysate antigen (TLA; 100 micrograms per head) in light mineral oil (LMO) twice at 2 weeks' interval. Each mouse was inoculated intraperitoneally with 10(2) erythrocytes infected with Babesia rodhaini 2 weeks after the second injection of the emulsion. The rates of decrease in the erythrocyte count, hemoglobin concentration, and hematocrit value 10 days after inoculation, as compared with the counterparts determined 1 day before inoculation, were distinctly lower in these treated mice than in untreated control mice. In the course of Babesia inoculations, substantial reduction in size and weight of the thymus became higher in untreated control than in TLA-treated mice as the infection progressed. In untreated controls, the number of Thy-1 positive (Thy-1 (+) ) cells was about 91.9% of the normal value being 3.7 X 10(7) cells in the whole thymus 1 day before inoculation while those in TLA-treated mice were 6.5 X 10(7) and 0.9 X 10(7) cells 1 day before inoculation and 10 days after inoculation, respectively. The size and weight of the spleen increased in both groups by day 10 after inoculation. The total number of Thy-1 (+) cells in the spleen was 3.9 X 10(7) and 11.7 X 10(7) 1 day before and 10 days after inoculations, respectively in untreated and 12.9 X 10(7) and 15.6 X 10(7), respectively in TLA-treated mice. The number of Thy-1 (+) cells in the liver was 0.5 X 10(7) and 1.2 X 10(7) 1 day before and 10 days after inoculations, respectively in untreated and 0.3 X 10(7) and 3.4 X 10(7), respectively, showing a rate increase of 1033.3% in TLA-treated mice. The rate of increase in count of Thy-1 (+) cells contained in the peripheral blood was 61.4% in the former and 64.1% in the latter. In untreated mice, degeneration and destruction of lymphocytes in the thymus and spleen follicles and aggregation of lymphocytes, which were not found in Thy-1 (+) staining, around pericapillary ducts in the liver were seen histopathologically 10 days after inoculation. In TLA-treated mice, however, perivascular infiltration by Thy-1 (+) lymphocytes and activation of Kupffer cells in the liver and activation of spleen follicles were observed locally 10 days after inoculation.

Animals↗
PubMed1987

Correlation between release of reactive oxygen intermediates and inhibition of Toxoplasma multiplication in mouse peritoneal and alveolar macrophages and kidney cells after in vitro incubation with Obioactin, lonomycin A, muramyl dipeptide, lipopolysaccharide or Toxoplasma lysate antigen.

The inhibition of Toxoplasma multiplication inside cells does not correlate with an enhanced release of oxygen intermediates except in the case of peritoneal macrophages treated with Obioactin. The inhibition observed in alveolar macrophages treated with Obioactin, in kidney cells treated with Obioactin or lonomycin A and in peritoneal macrophages treated with lonomycin A was not accompanied by an increment of release of oxygen intermediates. Lipopolysaccharide (LPS) and muramyl dipeptide (MDP) enhanced the release of toxic oxygen intermediates in peritoneal macrophages, but did not have any toxoplasmacidal effect. Adenosine triphosphate (ATP) content increased during Obioactin, MDP or Toxoplasma lysate antigen (TLA) treatment. The actual oxygen consumption of the peritoneal macrophages treated with Obioactin increased dose dependently, but that of TLA-, lonomycin A- or MDP-treated cells did not change. These results suggest that the relationship between the intracellular killing of Toxoplasma protozoa and the release of oxygen intermediates differs according to the cells and/or the stimuli, and that the cellular mechanism of Toxoplasma killing in the peritoneal macrophages treated with Obioactin involves an energy-dependent mechanism.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1987

Long-term in vitro suspension culture of Toxoplasma and HeLa cells.

To establish a method of mass and long-term propagation of Toxoplasma in suspension cultures and to find a technique for separating the organisms from host cells, basic investigations were carried out in a microcomputer controlled system. By using an arbitrary unit "the medium index" host HeLa cells were continuously supplied to Toxoplasma organisms for about 30 days, at cycles of 4 days. HeLa cells were well infected with Toxoplasma in the suspension cultures by leaving the medium unstirred for 15 min intervals. The separation of Toxoplasma organisms from cells was improved by treating toxoplasmas and HeLa cells mixtures with 0.4% trypsin. The total number of separated organisms obtained from 29 days cultivation period was 4.9 X 10(9). The mean generation time of Toxoplasma organisms on the 0, 10, 20 and 30 day's cultivation was calculated approximately 7.4, 9.4, 9.3 and 7.8 h, respectively.

Animals↗
PubMed1987

A case of ACTH-producing pheochromocytoma.

A woman with sustained hypertension, facial roundness, hirsutism, marked sweating, and generalized tremor was found to have a right adrenal pheochromocytoma. Elevated levels of serum cortisol, plasma ACTH, and serum catecholamines returned to normal after the tumor was removed. It was confirmed that enzymatically dispersed tumor cells produced ACTH and catecholamines concomitantly during in vitro incubation.

Adrenal Gland Neoplasms↗
PubMed1987

Postural suppression of plasma atrial natriuretic polypeptide concentrations in man.

The effects of sequential changes in posture, from recumbency, to sitting and then to the upright position, each for 60 min, respectively, on the levels of plasma immunoreactive atrial natriuretic polypeptide (ANP) in healthy human subjects were studied using a radioimmunoassay (RIA) method. At the end of each change in posture, plasma ANP levels were respectively 150 +/- 16.4 pg/ml (recumbent), 103 +/- 11.2 pg/ml (sitting), and 78.1 +/- 7.90 pg/ml (upright). In contrast, plasma renin concentration (PRC) and plasma aldosterone concentration (PAC) determined concomitantly with ANP showed a significant increase in response to the sitting and upright postures. Plasma ANP levels determined in normal subjects who remained in the recumbent posture for the same period did not show any significant change. This suggests that ANP is involved in the maintenance of haemodynamic homeostasis under physiological conditions and emphasizes that postural factors must be taken into account and controlled in order to evaluate plasma ANP levels properly, as well as those of PRC and PAC.

Adult↗
PubMed1987

Vagal regulation of insulin, glucagon, and somatostatin secretion in vitro in the rat.

Using a new in vitro procedure of the isolated perfused rat pancreas with vagal innervation, electrical vagal stimulation produced an increase in both insulin and glucagon secretion in proportion to the pulse frequency, but an inhibition in somatostatin release. When atropine was infused, both insulin and glucagon responses to vagal stimulation were partially suppressed, whereas somatostatin release was enhanced. In the presence of hexamethonium, vagal stimulation failed to affect insulin, glucagon, or somatostatin secretion. Propranolol partially blocked both insulin and glucagon responses but did not influence somatostatin response. Phentolamine had no significant effect on release of hormones. Simultaneous administration of propranolol and phentolamine tended to inhibit both insulin and glucagon responses to vagal stimulation. These findings suggest that not only a cholinergic but also a noncholinergic neuron may be involved in vagal regulation of pancreatic hormone secretion and that these neurons may be under the control of preganglionic vagal fibers via nicotinic receptors.

Animals↗
PubMed1987

The radioimmunoassay for human plasma atrial natriuretic peptide--its application to uremic patients.

A highly sensitive radioimmunoassay for alpha-human atrial natriuretic peptide (alpha-hANP) was established and applied to measure the human plasma alpha-hANP levels. In our assay system, anti-alpha-hANP antiserum was raised in albino rabbits by intradermally injecting synthetic alpha-hANP which was conjugated with bovine serum albumin. The final antiserum dilution was 1:50,000. Sensitivity was 2 pg/tube and the 50% intercept was at 28 pg/tube. The plasma alpha-hANP was extracted using a Sep-Pak C-18 cartridge. According to this procedure, the mean recovery was 73.8 +/- 3.4% (mean +/- SE). The averaged plasma levels of immunoreactive alpha-hANP (i alpha-hANP) in normal subjects were 24.8 +/- 2.1 pg/tube. In patients with chronic renal failure undergoing hemodialysis, the averaged plasma i alpha-hANP levels were 56.4 +/- 5.0 pg/ml before hemodialysis. Plasma i alpha-hANP levels were significantly higher in the patients with chronic renal failure than in the normal subjects. After hemodialysis, plasma i alpha-hANP levels decreased significantly (32.2 +/- 2.8 pg/ml). These results suggest that the alteration in extracellular fluid volume (ECFV) may affect the plasma levels of i alpha-hANP in patients with chronic renal failure under hemodialysis; i.e., an increase in ECFV elevates and a decrease in ECFV lowers the circulating levels of alpha-hANP.

Animals↗
PubMed1987

[Prognostic significance of pretreatment CT scans in supratentorial astrocytomas receiving radiotherapy].

Pretreatment brain CT scans of 61 patients receiving radiation and chemotherapy for supratentorial gliomas (23 low-grade astrocytomas, 21 grade III astrocytomas and 17 glioblastomas) were reviewed, and their prognoses were analyzed. Almost all gliomas with no CEA (contrast enhanced area) were low-grade, and their prognosis was promising. Benign and malignant gliomas with regular CEA were found in equal proportions, and their prognosis was relatively good. A majority of cases with irregular or ring-like CEA were malignant, and their prognosis was extremely poor.

Adolescent↗
PubMed1987

Plasma levels of atrial natriuretic peptide in patients with chronic liver disease.

The plasma levels of atrial natriuretic peptide were determined by radioimmunoassay in 24 patients with chronic liver disease, including three patients with alcoholic liver disease, four with chronic active hepatitis, 13 with liver cirrhosis, and four with hepatocellular carcinoma. When compared with normal subjects (180 +/- 12 pg/ml), the plasma levels of atrial natriuretic peptide in cirrhotic patients (349 +/- 64 pg/ml) were significantly elevated (p less than 0.001) but not in other disease groups. In patients with chronic liver disease the plasma levels of atrial natriuretic peptide were correlated significantly with plasma renin activity but not with plasma aldosterone, and furthermore showed a negative correlation with indocyanine green disappearance rate. These results suggest that the increased plasma levels of atrial natriuretic peptide, which appear to be associated with an increase in plasma renin activity and with hepatic dysfunction, may participate in maintaining homeostasis of sodium and fluid volume in patients with chronic liver disease.

Aldosterone↗