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Biomedical subjects

S Nakazawa

Publications and source records attributed to S Nakazawa.

At least 163 records · Page 9Linked to original sources
PubMed1995

[A study of the relationship between nocturnal intragastric pH and sleep stages of peptic ulcer].

We studied the correlation of the gastric acid secretion and the depth of sleep at night with no medication in 32 cases (19 gastric ulcer, 6 duodenal ulcer patients and 7 healthy controls). Using Memory PH: Monitor intragastric pH values were consecutively measured without antiulcer drugs. The depth of sleep were monitored continuously by recording without any sleeping drugs. In healthy controls, the pH values of awake phase was significantly lower than that of sleep stage 1, 4 and rapid eye movement (REM) phases. The pH values of REM phases were significantly high rather than that of sleep stage 1 and 2 phases. In patients with gastric ulcer, the pH values of awake phases were significantly lower than that of sleep stage 1 and REM phases. The pH values of REM phases were significantly high rather than that of the other sleep stages. On the other hand, in patients with duodenal ulcer, the obvious changes of the pH values were not seen with sleep stages. The pH values of healthy controls and gastric patients were changed with sleep stages. But the pH of duodenal ulcer patients were not changed obviously. Therefore, it is suggested that the dysfunction of autonomous nervous system was influenced the nocturnal intragastric pH in the patients with duodenal ulcer and played one of the important role in the occurrence of duodenal ulcer.

Adult↗
PubMed1995

[A case of multiple cerebral aneurysm which showed rapid growth caused by left atrial myxoma].

A 24-year-old woman was admitted complaining of right hemiparesis and episodes of syncope. Computed tomography demonstrated a low density area in the left putaminal region. Intravenous digital subtraction angiography (IVDSA) showed two aneurysms in the distal segment of the right middle cerebral artery. Cerebral emboli from a cardiac source was suspected, and cardioechography was performed. Myxoma was located in the left atrium. The patient was transferred to a cardio surgical unit, and the myxoma was successfully removed. After removal by operation of the cardiac tumor, follow-up third IVDSA was performed. One aneurysm of the distal segment of the right middle cerebral artery had grown larger. On the other hand, the other aneurysm had disappeared. Clipping of the enlarged aneurysm was performed. After the clipping operation of the enlarged aneurysm, a follow-up 4th IVDSA was performed. A new aneurysm of the proximal segment of the left cerebral artery was observed. A follow-up 5th IVDSA was performed, revealing that the new aneurysm was enlarging. No operation was performed, because the aneurysm was the fusiform type. At present, the patient is complaining of slight right hemiparesis and has returned to her job. Here we reported a case of cerebral aneurysm caused by left atrial myxoma.

Adult↗
PubMed1995

A novel monoclonal antibody, KOR-SA3544 which reacts to Philadelphia chromosome-positive acute lymphoblastic leukemia cells with high sensitivity.

A monoclonal antibody which primarily reacted with Philadelphia chromosome (Ph1)-positive ALL cells was produced. The reactivity of a monoclonal antibody, KOR-SA3544 (IgG2a) was evaluated on normal hemopoietic cells, 68 leukemic cell lines and freshly obtained cells from 190 patients with leukemia and lymphoma. In cultured cells, KOR-SA3544 reacted with Ph1-positive ALL cell lines (5/5) and leukemic cell lines with 11q23 translocation (3/11). In lymphoid cells, KOR-SA3544 was reactive with all of Ph1-positive ALL (26/26), a part of common ALL (5/38) and one case of early B precursor leukemia with 11q23 translocation, but not with peripheral lymphocytes. Normal mature granulocytes were also strongly stained. In myeloid leukemias, KOR-SA3544 was positive (16/56) only in patients with acute myeloid leukemia with FAB-M2 and overt leukemia following myelodysplastic syndrome, but neither with other types of myeloid leukemias nor with blast crisis in chronic myelogenous leukemia. KOR-SA3544 recognized a 90 KDa protein on the membrane of a leukemic cell line, KOPN-57bi. In normal bone marrow, CD19+/KOR-SA3544+ cells were not identified, while Ph1-positive ALL cells were strongly positive for both antibodies. KOR-SA3544 is useful not only for making the diagnosis of Ph1-positive ALL but for detection of the minimal residual disease during remission.

Antibodies, Monoclonal↗
PubMed1995

Gastric ulcer: can endoscopic ultrasonography predict healing?

The course of healing of gastric ulcers and their relapse were examined, based on observation of the cross-sections of gastric ulcers using endoscopic ultrasonography. This study concludes that EUS can predict ulcer healing and it is suggested that the strategy be planned based on the findings from EUS.

Endoscopy, Digestive System↗
PubMed1995

Relationships between biochemical abnormalities and anthropometric indices of overweight, adiposity and body fat distribution in Japanese elementary school children.

OBJECTIVE: To determine the anthropometric indices linked to the biochemical risk factors for atherosclerosis in Japanese obese elementary school children, ages ranging from 6 to 12 years. DESIGN: Cross-sectional study of obese children based on fasting blood samples. SETTING: Outpatient clinic of University Hospital. SUBJECTS: 65 consecutive patients with simple obesity (38 boys and 27 girls), and age-matched controls, 184 boys and 205 girls. MAIN OUTCOME MEASURES: Percent obesity and body mass index as indices of being overweight; percent body fat and the sum of four skinfold thicknesses as indices of adiposity; waist-to-hip circumference ratio and waist-to-thigh circumference ratio as indices of body fat distribution. The anthropometric indices were standardized by calculating standard deviation scores based on data from control children. RESULTS: In the obese boys, all six anthropometric indices studied correlated closely with serum biochemical indices, and strong correlations were observed among the indices of overweight, adiposity and body fat distribution. In contrast, only the indices of body fat distribution, not those of overweight or of adiposity, were correlated with serum biochemical indices in the obese girls. No relationship was found between the indices of body fat distribution and the other anthropometric indices in the obese girls. Thus, the profile of the obese girls differed from that of their male counterparts. CONCLUSION: The results suggest that body fat distribution is related to certain biochemical complications of childhood obesity, and that androgyny in fat patterns induces metabolic derangements in children.

Adipose Tissue↗
PubMed1995

Stromal cell-mediated transcriptional regulation of the CD13/aminopeptidase N gene in leukemic cells.

CD13/aminopeptidase N (APN) is a cell surface metallopeptidase expressed by normal and leukemic myeloid cells, and by lymphoblasts in 5-10% of acute lymphoid leukemia (ALL) cases, previously classified as 'biphenotypic' or 'mixed-lineage' leukemias. In fresh cells from two early B-lineage, t(9;22)-positive, ALL cases that were CD13/APN-negative at diagnosis, high levels of CD13/APN expression were induced after 3 days of in vitro culture. Similarly, continuously growing cell lines established from these ALLs, KOPN-30bi and KOPN-57bi, expressed CD13/APN, but retained other phenotypic, cytochemical and molecular features of early B-lineage cells. After 7 days of culture on human bone marrow stromal layers or murine S17 stromal cells, levels of CD13/APN expression by the leukemic cell lines decreased by more than 4-fold. After 21 days of culture on stromal cells, CD13/APN became undetectable by flow cytometry; however, the original levels of expression were regained when the cell lines were cultured without stroma. A more moderate decrease in CD13/APN expression was also observed in the myeloid lines KG-1 and HL-60 during culture on stroma. Suppression of CD13/APN expression required contact with stroma, but did not depend on VLA-4-mediated adhesion. Surprisingly, the mechanism through which stromal cells down-regulated CD13/APN expression in leukemic cells involved suppression of transcription from the CD13/APN gene. Contact with stroma resulted in a 2-3-fold decrease in CD13/APN mRNA expression and near ablation of CD13/APN gene transcription in nuclear run-on assays. Thus, CD13/APN expression by leukemic cells is regulated by interactions with the bone marrow microenvironment. CD13/APN expression in some ALL at diagnosis could result from a block in the signal transduction pathways that cause its suppression by bone marrow stromal cells.

Bone Marrow Cells↗
PubMed1995

[Surgical treatment of 22 primary cardiac myxomas].

We report surgical treatment of 22 patients with primary cardiac myxomas, including 17 left atrial (LA), 3 right atrial (RA), 1 left ventricular and 1 right ventricular myxomas. Eighteen patients manifested congestive heart failure, and an embolic episode was observed in 5 patients preoperatively. Inflammatory laboratory findings were observed in 16 patients. One case of RA myxoma was complex cardiac myxoma. A transverse biatrial approach was useful for removal of large LA myxomas and when the attachment of the tumor was unconfirmed preoperatively. There were no hospital deaths. Stroke occurred in 1 and supraventricular arrhythmia in 3 patients in the early postoperative period. There were 2 late deaths unrelated to cardiac myxomas. No signs of recurrence have been observed.

Aged↗
PubMed1995

[Improvement of highly reproducible technique of four-vessel occlusion model and its study on metabolic changes of cerebral reperfusion in rats].

The four-vessel occlusion method introduced by Pulsinelli et al is widely used as an experimental model for reversible forebrain ischemia in rats. However, this model has a major problem in the difficulty assuring complete occlusion of the vertebral arteries by electrocauterization through the alar foramina of the first cervical vertebra. Anatomical basis of the vertebral artery suggested by Sugio et al indicates that the vertebral artery at the level of the second cervical vertebral is visible. In this study, we further developed highly reproducible model of reversible forebrain ischemia, which is modified four-vessel occlusion in rats. Male Wistar rats were subjected to four-vessel occlusion. Under microscope the visible vertebral arteries at the second vertebra could be easily electrocauterized and completely cut by microscissors to yield complete cessation of circulation of bilateral vertebral arteries without failure. After 24 hours, animals were subjected to 15, 30 and 45 minutes of forebrain ischemia by occluding both common carotid arteries with Sugita's temporary clips. 31P-magnetic resonance spectroscopy (31P-MRS) were obtained with a 6.3-T spectrometer to investigate sequential change of the in vivo brain energy metabolism. Our studies indicated that high energy phosphorus compounds were reduced in a few minutes after the induction of the forebrain ischemia, and they returned to the normal level after the recirculation. In addition, we monitored electroencephalogram (EEG) during the whole experimental period. The EEG showed a flat pattern after the induction of ischemia, and EEG recovered normal pattern within 12 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

A reverse transcriptase-polymerase chain reaction detects heterogeneous chimeric mRNAs in leukemias with 11q23 abnormalities.

The MLL gene involved in 11q23 translocations found in the majority of infantile leukemias and some secondary leukemias makes fusion transcripts with genes such as LTG4 (chromosome 4), LTG9 (chromosome 9), and LTG19 (chromosome 19) as a result of reciprocal translocation. We have examined 25 cases of leukemias with 11q23 abnormalities by Southern blot analysis and the reverse transcriptase-polymerase chain reaction (RT-PCR). Using various primer pairs, chimeric mRNAs could be amplified in 6 of 7 leukemias with t(4;11), 6 of 8 leukemias with t(9;11) including secondary leukemia, 8 of 9 leukemias with t(11;19), and 1 with a deletion at 11q23. The chimeric mRNAs were heterogeneous and differential usage of the MLL exons was found, irrespective of the partner chromosomes. Sensitivity studies showed that a single clone with chimeric mRNA in 10(4) to 10(5) cells could be detected. These findings show that the present RT-PCR settings provide a rapid, accurate, and sensitive tool for diagnosing leukemias with 11q23 translocations and for monitoring response to therapy in these patients.

Adult↗
PubMed1994

Combined warfarin and antiplatelet therapy after St. Jude Medical valve replacement for mitral valve disease.

OBJECTIVES: The clinical effect of combined warfarin and antiplatelet therapy on the incidence of stroke and postoperative complications after mitral (plus aortic) valve replacement was studied and compared with that observed with warfarin therapy alone. BACKGROUND: It has been reported that combined warfarin and antiplatelet therapy may be effective but may be associated with an increased hemorrhagic risk. Therefore, definite benefits of the treatment in patients with an implanted prosthetic valve have not been clearly documented. METHODS: Between January 1980 and December 1992, 195 patients with a St. Jude Medical valve at the mitral (plus aortic) position were assigned to receive treatment with either warfarin alone (125 patients) or warfarin plus antiplatelet agents (70 patients), such as dipyridamole (150 or 300 mg daily, 14 patients) or ticlopidine (200 or 400 mg daily, 56 patients). A minimal dose of aspirin (10 to 40 mg) was added (29 patients) if the maximal platelet aggregation rate by collagen was not reduced. The target thrombotest level was 10% to 20%. RESULTS: The two treatment groups were similar with regard to gender and age distribution. The number of patients with atrial fibrillation, left atrial thrombus, history of previous stroke, simultaneous aortic valve operation and previously performed valve procedures were comparable in the two groups. Actuarial survival rate at 10 years was 98.3 +/- 1.7% (mean +/- SD) in the warfarin plus antiplatelet group and 90.3 +/- 3.2% in the warfarin group (p < 0.05 at 1 and 9 to 12 years). The actuarial stroke-free rate at 10 years was 95.3 +/- 3.4% and 84.3 +/- 3.8%, respectively (p < 0.05 by the generalized Wilcoxon test). The actuarial complication-free rate at 10 years was 89.4 +/- 4.3% and 67.9 +/- 4.8%, respectively (p < 0.05 by the generalized Wilcoxon test). No hemorrhagic complications were seen in the warfarin plus antiplatelet group. CONCLUSIONS: The results strongly indicate the effectiveness and safety of combined warfarin plus antiplatelet treatment after St. Jude Medical valve replacement for mitral (plus aortic) valve disease.

Actuarial Analysis↗
PubMed1994

A nonhuman primate model for human cerebral malaria: rhesus monkeys experimentally infected with Plasmodium fragile.

We studied the brains of rhesus monkeys infected with the primate malaria parasite Plasmodium fragile. Electron microscopy showed that, in these animals, erythrocytes infected with P. fragile undergo sequestration and that parasitized red blood cells adhere to endothelial cells in the cerebral microvessels by means of knobs. Cerebral microvessels with sequestered parasitized red blood cells were shown by immunohistochemical analysis to possess the platelet glycoprotein CD36, thrombospondin, and intracellular adhesion molecule-1. The formation of rosettes also was observed in the cerebral microvessels. In a fashion similar to human cerebral malaria, P. fragile produced neurological symptoms in the animals. Thus, rhesus monkeys infected with P. fragile, like those monkeys infected with Plasmodium coatneyi, can be used as a primate model to study human cerebral malaria.

Animals↗
PubMed1994

Ultrastructural localization of CD36 in human hepatic sinusoidal lining cells, hepatocytes, human hepatoma (HepG2-A16) cells, and C32 amelanotic melanoma cells.

Ultrastructural localization of CD36 in human hepatic sinusoidal lining cells, hepatocytes, human hepatoma (HepG2-A16) cells, and C32 amelanotic melanoma cells. Experimental Parasitology 79, 383-390. CD36 is expressed in the endothelial cells of some human organs, but the ultrastructural localization of this molecule in the sinusoidal lining cells of human liver is not well established. We report the ultrastructural localization of CD36 in the liver using a novel murine monoclonal antibody against CD36, namely MO30, as a primary antibody. Immunocytochemistry by the postembedding method showed that CD36 was localized in endothelial cells of sinusoids and in hepatocyte microvilli protruding into the space of Disse. Moreover, in cultured human hepatoma (HepG2-A16) cells and C32 amelanotic melanoma cells, MO30 reacted with microvilli. Hence, CD36 expressed on these cells may be involved in recognition and/or entry of these cells by malaria sporozoites.

Amino Acid Sequence↗
PubMed1994

Malaria-induced increase of splenic gamma delta T cells in humans, monkeys, and mice.

The number and distribution of gamma delta T cells in spleens from patients who died of cerebral malaria and from rhesus monkeys severely infected with Plasmodium coatneyi were examined by immunocytochemistry. gamma delta T cells were significantly increased in these spleens. In a rodent malaria model using Plasmodium chabaudi adami, an avirulent strain of murine malaria parasites, the degree of parasitemia appears to be modulated by the number of gamma delta T cells in the spleen. As parasitemia increases, these T cells increase in number. At some critical point, gamma delta T cells in collaboration with macrophages and alpha beta T cells apparently start to clear parasitized erythrocytes from the blood, leading to an abatement of the parasitemia, which is followed by a reduction in the number of gamma delta T cells. This gamma delta T cell phenomenon may be responsible for the self-limiting infection in mice.

Animals↗
PubMed1994

Simple quantitative evaluation of blood-brain barrier disruption in vasogenic brain edema.

Traumatic damage to the brain results in blood-brain barrier disruption with subsequent formation of vasogenic brain edema. The goal of this study was to evaluate a colorimetric assay of Evans blue extravasation for quantitatively studying blood-brain barrier disruption. Vasogenic brain edema was produced by a cortical freezing lesion. 52 male Wistar rats were sacrificed and cardiac perfusion was performed. A volume of dimethylformamide, twice the brain weight, was added to the brain and this was incubated for 72 hours. The supernatant was analyzed spectrophotometrically. Evans blue contents in the lesioned hemisphere was significantly increased within one hour after the lesion production relative to the normal brain and continued to increase for 24 hours (p < 0.01). This quantitative assay of Evans blue is a simple method for evaluation of blood-brain barrier disruption in vasogenic brain edema.

Animals↗
PubMed1994

Early changes of blood-brain barrier and superoxide scavenging activity in rat cryogenic brain injury.

Cryogenic brain injury results in blood-brain barrier (BBB) disruption which may be mediated in part by oxygen free radicals. In this study, sequential changes of BBB and endogenous superoxide scavenging activity were investigated in brains subjected to cryogenic injury. 92 male Wistar rats were sacrificed at 15, 30 minutes, 1, 2, 3, 4, 6, 24 and 48 hours after the lesion. The extent of BBB disruption was determined by quantitative assessment of Evans blue (EB) uptake based on extraction from tissue using dimethylformamide. Determination of endogenous superoxide scavenging activity in the injured brain was performed by electron spin resonance spectrometry using a spin trapping agent. Superoxide scavenging activity was significantly decreased within one hour after the injury relative to normal rat brain (p < 0.05, student's t test) persisting for at least 6 hours. The EB content in the lesioned hemisphere was significantly increased within one hour after the injury relative to the normal rat brain (p < 0.01) and continued to increase for 24 hours. In conclusion, early changes of BBB and endogenous superoxide scavenging activity in rat cryogenic injured brain indicate that BBB may be an early target for oxygen free radicals in cryogenic brain injury.

Animals↗
PubMed1994

Purification and immunoelectron microscopic localization of cellular glutathione peroxidase in rat hepatocytes: quantitative analysis by postembedding method.

To measure quantitatively the intracellular distribution of cellular glutathione peroxidase (GPX) in rat hepatocytes, ultrathin sections were stained by a postembedding immunogold technique. GPX had a specific activity of 1670 Units/mg protein, and was purified 2050-fold from rat liver by means of heat denaturation, ammonium sulfate fractionation, and a series of chromatographic procedures including thiol-Sepharose 4B. The purified GPX was shown to be electrophoretically pure, and was a homotetramer of 22 kDa subunits. Monospecific polyclonal antibodies were raised in rabbits by immunization. By immunoblot analysis, both the light mitochondrial the and cytosolic fractions of rat liver homogenate gave a single band with an identical mobility to that of the purified enzyme. Under the light microscope, hepatocytes showed nuclear staining and granular cytoplasmic staining, corresponding to certain intracellular structures. The labeling density (number of gold particles/microns 2) for GPX obtained by immunoelectron microscopy was 11.9 in the nuclei, 19.6 in mitochondria, 3.32 in peroxisomes, 1.95 in lysosomes, and 9.81 in the cytoplasmic matrix. These results suggest that cellular GPX is present in various compartments of rat hepatocytes, and that the GPX occurs in relatively higher amounts in mitochondria.

Animals↗
PubMed1994

Hypomethylated status, but not RAG-1, is required for T-cell receptor-beta-chain gene rearrangement in acute leukemia cells.

We studied the relation between the level of recombinase activating gene (RAG-1) and the methylation status of T-cell receptor (TCR)-beta-chain gene in TCR-beta rearrangement in acute leukemias, including 21 patients with B-precursor acute lymphoblastic leukemia (ALL) and 23 with acute myeloid leukemia (AML). The rearrangement of the TCR beta-chain gene in acute leukemia always occurs at the allele that contains hypomethylated cytosine-cytosine- guanine-guanine (CCGG) sequences within either the TCR-J beta 1 or TCR-J beta 2 regions. Moreover, all B-precursor ALL patients with TCR-beta rearrangement had hypomethylated TCR-beta with or without the presence of RAG-1 activity detectable by reverse transcript-polymerase chain reaction, whereas none of the AML patients with TCR-beta rearrangement and hypomethylated TCR-beta had detectable RAG-1 activity. Some ALL patients had hypomethylated TCR-beta and RAG-1 activity without TCR-beta rearrangement, and most of them showed t(4;11)(q21;q23) or t(9;22)(q34;q11). These results indicate a correlation between the hypomethylation status of the TCR-beta and its rearrangements, but some unknown blockage factor for this association exists in B-precursor ALL patients with specific chromosomal translocations.

Acute Disease↗