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Biomedical subjects

S Yamaguchi

Publications and source records attributed to S Yamaguchi.

At least 451 records · Page 25Linked to original sources
PubMed1997

Severe thrombocytopenia suggesting immunological mechanisms in two cases of vivax malaria.

Case 1: A 27-year-old woman, referred to our hospital because of relapsing fever after travel to Thailand, was given a diagnosis of vivax malaria. Clinical investigation revealed thrombocytopenia, elevated platelet-associated IgG (PAIgG), and negative antibody against Plasmodium vivax antigen. After antimalarial treatment, the levels of both the platelets and PAIgG returned to normal. Case 2: A 28-year-old Sri Lankan man was admitted to our hospital with a complaint of fever. The patient had thrombocytopenia, elevated PAIgG, and positive antibody against Plasmodium vivax antigen. He contracted malaria in Sri Lanka about 6 months prior to this admission. After treatment, the platelet count and PAIgG level returned to normal. In these two cases, high levels of PAIgG may have been involved in the development of the thrombocytopenia. In the first patient, in particular, the thrombocytopenia was thought to be induced by some immunological mechanism prior to the detection of antimaralial antibodies in serum.

Adult↗
PubMed1997

Identification of three lineages of wild measles virus by nucleotide sequence analysis of N, P, M, F, and L genes in Japan.

The nucleotide sequences of nucleocapsid (N), phosphoprotein (P), matrix (M), fusion (F), and large protein (L) genes were partly determined for 19 wild strains of measles virus (MV) isolated over the past 10 years in Japan (nucleotide position N: 1301-1700, P: 1751-2190, M: 3571-4057, F: 6621-7210, L: 10381-11133) and also for a MV strain obtained from a patient with subacute sclerosing panencephalitis (SSPE) who had natural measles in 1980. The phylogenetic trees of these strains drawn for respective genes were very similar to each other and revealed that all the wild strains were classified chronologically into 3 subgroups, those isolated in 1984, 1984-1989, and 1990-1994. The SSPE strain was classified into the subgroup of 1984. Phylogenetic tree analyses including other strains in the world revealed that Japanese strains in 1984 were classified into a distinct lineage which might correlate with the European strains from late 1970s to mid 1980s. Japanese strains from 1984 to 1989 were almost identical to those of the United States isolated from 1989 to 1992, and Japanese strains in 1990s were related closely to some of the MV strains isolated in 1994 in the United States. Genetic recombination among the MV genes seemed not to have occurred.

Adolescent↗
PubMed1997

Characterization of protein components of human urinary crystal surface binding substance.

We previously extracted crystal surface binding substance (CSBS) from human urine and showed that it appeared to constitute a substantial proportion of urinary macromolecular inhibitors of calcium oxalate crystallization. CSBS was isolated from human urine and fractionated by three consecutive chromatography procedures in order to characterize protein inhibitors of calcium oxalate crystallization. Sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and NH2-terminal amino acid sequencing revealed that inhibitory fractions eluted from a final, hydroxyapatite column contained prothrombin and osteopontin. Hydroxyapatite column fractions also contained other, unidentified protein inhibitors of calcium oxalate crystallization. CSBS contained also human serum albumin, alpha 1-acid glycoprotein, alpha 1-microglobulin, alpha 2-HS glycoprotein, retinol-binding protein, transferrin, and Tamm-Horsfall protein, but these proteins seemed to play no direct role in inhibitory activity.

Adult↗
PubMed1997

Multivariate analysis of the prognostic factors of patients with unresectable synchronous liver metastases from colorectal cancer.

PURPOSE: It frequently is observed that widely varying prognoses are given for patients with the same extent of liver metastases from colorectal cancer, even though the same treatment is performed on these patients. One of the reasons for this variance is that prognostic factors for these patients have not been defined. This study was designed to elucidate which clinicopathologic factors were the most important in the prognosis of 73 patients with unresectable synchronous liver metastasis from colorectal cancer. METHODS: Univariate and multivariate analysis of 11 clinicopathologic factors were performed using the Cox proportional hazard model. Survival curves were generated using the Kaplan-Meier method. RESULTS: Extent of liver metastases was the most significant variable in this survival analysis, although the extent of lymph node metastases of the primary lesion also was significant. However, the method of treatment was not a significant determinant in the survival for patients with unresectable liver metastases. Median survival of patients with H1, H2, and H3 was 13, 12, and 6 months, respectively, and there was a significant difference between survival curves for patients with H1 and patients with H3. Median survival of patients with n0, n1, and n2 was 13, 7, and 7 months respectively, and there was a significant difference between survival curves for patients with n0 and patients with n2. Median survival of 6 patients with H1 and n0 and of 17 patients with H3 and n2 was 28 and 4 months, respectively. There was a significant difference in survival curves between these two groups. CONCLUSION: Longevity of patients with unresectable synchronous liver metastases from colorectal cancer is affected adversely by the presence of nodal metastases and extent of liver metastases. This should be considered in the planning treatment.

Adult↗
PubMed1997

Suppressive effects of Y-24180, a receptor antagonist to platelet activating factor (PAF), on antigen-induced asthmatic responses in guinea pigs.

OBJECTIVE AND DESIGN: Effects of Y-24180 on antigen-induced asthmatic responses were evaluated in actively sensitized guinea pigs and the effects were compared with those of several anti-asthmatic drugs. MATERIALS: Male Hartley guinea pigs were used. TREATMENT: Guinea pigs were actively sensitized with ovalbumin and were pretreated with pyrilamine Y-24180 was orally administered to the animals 3 h and others were 1 h before the antigen challenge. METHODS: The airway hyperresponsiveness was measured according to the method of Konzett and Rössler with some modifications. The immediate asthmatic response (IAR) and late asthmatic response (LAR) were measured by the oscillation method. Inflammatory cells infiltrated into the lungs were counted after the bronchoalveolar lavage. RESULTS: Under oral administration before or after the challenge with antigen, Y-24180, OKY-046, and ONO-1078 suppressed the antigen-induced airway hyperresponsiveness. Moreover, Y-24180, ONO-1078, AA-2414, and theophylline suppressed both the IAR and LAR, but OKY-046 only suppressed the LAR. Among the test drugs, only Y-24180 and theophylline suppressed the antigen-induced accumulation of eosinophils in the bronchoalveolar lavage fluid. CONCLUSIONS: The data indicate practical participation of PAF in the development of antigen-induced asthmatic responses in animals, and usefulness of Y-24180 in the clinical treatment of asthma as well as other anti-asthmatic drugs.

Administration, Oral↗
PubMed1997

Magnetic resonance imaging with fluid-attenuated inversion recovery pulse sequences in MELAS syndrome.

We report the brain magnetic resonance imaging findings in the case of a 5-year-old boy with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS). Fluid-attenuation inversion recovery (FLAIR) imaging revealed multifocal abnormal cortical signals which were difficult to see on conventional T1- and T2-weighted images. Although the patient was in an advanced clinical stage of disease and had severe cortical atrophy, FLAIR imaging demonstrated characteristic findings of MELAS.

Atrophy↗
PubMed1997

Dose-response effects of adrenergic drugs on axial movements of the rat mandibular incisor and on arterial blood pressure.

Axial tooth movements and arterial blood pressure were measured following the intravenous injection of 0, 0.01, 0.1, 1, or 10 micrograms/kg of adrenaline, noradrenaline or isoprenaline. Adrenaline caused a dose-dependent, rapid, extrusive tooth movement with a nearly simultaneous increase in blood pressure, followed by a marked intrusive tooth movement and a decrease in blood pressure. Noradrenaline caused a dose-dependent, rapid, extrusive tooth movement and an increase in blood pressure, but a subsequent intrusive tooth movement and decrease in blood pressure were not so marked. Isoprenaline caused a marked intrusive tooth movement and a decrease in blood pressure, without an extrusive tooth movement and increase in blood pressure. The time required to reach the maximum intrusive tooth movement was delayed after that to reach the maximum decrease in blood pressure. The recovery time of the intrusive tooth movement was much more delayed than that of blood pressure. These results suggest that the extrusive movement of the rat incisor was primarily related to the rise of arterial blood pressure due to stimulation of vascular alpha-receptors. It is also suggested that stimulation of beta-receptors would probably cause vasodilatation of arteries that would make the pressure in the small vessels in the microcirculation of the socket fall, so reducing the volume of blood and interstitial fluid in the socket followed by a marked and continuing intrusive tooth movement.

Adrenergic Agonists↗
PubMed1997

Classification and treatment of vertebral dissecting aneurysm.

BACKGROUND: For many years, dissecting aneurysms of the intracranial vertebral artery were believed to be quite rare. In recent years, because vascular disorders have been studied more thoroughly by three dimensional-computed tomography (3D-CT), angiographically and pathologically, these aneurysms are being reported with more frequency. METHODS: Among the 45 patients diagnosed to have aneurysms arising from the vertebral artery or its branches over a 20-year period, 16 had dissecting aneurysms. The authors present their therapeutic strategy for these patients. Surgery was performed in the 16 patients, the most common technique being clip-occlusion or trapping of the parent artery wherever feasible, in an attempt to optimize cerebral blood flow. The dissecting aneurysms of the vertebral artery were classified into two groups for the purpose of determining a therapeutic approach, namely unilateral and circumferential groups. In the unilateral group, the dissection seemed to involve only on one side of the vessel according to the conventional cerebral angiogram. These patients underwent surgical reconstruction of the vertebral artery by direct clipping. In the circumferential group, the dissection was all around the artery. Proximal clipping or trapping was performed in this group. RESULTS: In six out of eight patients with unilateral dissecting aneurysms, vascular reconstruction was possible by direct clipping. Of these six patients, the surgical outcome was considered excellent in four, fair in one, and one patient died of cardiac failure after 12 days as his preoperative morbid condition remained the same after surgery. Two other patients with unilateral dissecting aneurysms were treated with trapping technique and the surgical outcome was excellent in one patient and good in the other patient. Both patients resumed a normal social life. In five out of eight patients with circumferential dissecting aneurysms, trapping or proximal clipping was performed and the surgical outcome was excellent in two patients, good in one and fair in one patient. One patient with preoperative brain stem infarction died of aspiration pneumonitis after 8 months. Two patients who were noted to have an increase in the size of aneurysm during follow-up angiography underwent a craniotomy with clipping and wrapping of the aneurysm. There was a favorable surgical outcome in both patients. The remaining three patients had Grade IV subarachnoid hemorrhage (SAH) prior to surgery and at autopsy a disturbed vascular wall was detected. CONCLUSION: The authors' experience suggests that when surgically feasible, direct clipping is an effective alternative approach in the treatment of dissecting aneurysms of the vertebral artery in which blood flow in the parent artery is to be preserved.

Adult↗
PubMed1997

Operation on high-lying basilar bifurcation aneurysms.

BACKGROUND: The surgical approach to basilar bifurcation aneurysms is a complicated procedure, especially with those located high in the interpeduncular cistern. We have developed a surgical approach to these aneurysms involving only a small anterior temporal craniotomy and detachment of the zygomatic arch. METHODS: The skin incision is placed 5 mm below the inferior border of the zygomatic arch and 5 mm anterior to the tragus, extending on towards the eyebrow but well within the hairline. The zygomatic arch is detached on either side followed by a small temporal craniotomy exposing the anterior temporal lobe. The temporal lobe is retracted and the internal carotid artery, posterior cerebral artery, posterior communicating artery, and inferior aspect of the optic chiasma are exposed. RESULTS: We have performed a transzygomatic anterior subtemporal approach in 12 patients with high-lying basilar bifurcation aneurysm. Eight patients demonstrated a good recovery as per the Glasgow outcome scale and four patients had a moderate disability that correlated with a poor WFNS grade preoperatively. One patient had an oculomotor palsy and another experienced a small infarction postoperatively. CONCLUSIONS: This approach is a suitable procedure for high-lying basilar bifurcation aneurysms in the interpeduncular cistern and 1.2 cm above the clinoid process.

Aged↗
PubMed1997

Immunohistochemical study of endothelin-1 in preeclamptic nephropathy.

Whether the serum levels of endothelin, a vasoconstrictive peptide produced in the endothelial cell, increase in preeclamptic patients is still controversial. We performed immunohistochemical studies to observe the changes in endothelin-1 (ET-1) in preeclamptic kidney tissues. The monoclonal anti-human ET-1 antibody (Yamasa, Japan) and anti-von Willebrand factor (vWF, Dako, Denmark), a marker of endothelial cells, were used for the studies by the strepto-avidin-biotin peroxidase method (ABC-POD Kit, Wako, Japan). Twenty-nine patients and 12 normal controls were divided into four groups. The preeclamptic group included 14 patients diagnosed with preeclampsia by clinical symptoms of hypertension, proteinuria, and edema occurring in late pregnancy and as having preeclamptic nephropathy. They underwent renal biopsy 16.7 +/- 1.0 (mean +/- SEM) days after delivery. The nephrotic group comprised 10 normotensive nonpregnant patients with nephrotic-range proteinuria examined through biopsy before treatment (six cases of minimal change, two of focal segmental glomerulosclerosis, one of membranous nephropathy, and one of IgA nephropathy). The pregnant women with preexisting glomerular disease group included five pregnant women with normal renal function who were normotensive and had no increase in the amount of proteinuria throughout pregnancy. They underwent renal biopsy 10.8 +/- 2.9 days after delivery (two cases of membranous nephropathy, one of focal segmental glomerulosclerosis, one of thin basement membrane disease, and one of non-IgA mesangioproliferative glomerulonephritis). The normal kidney group comprised 12 healthy tissue samples taken from nephrectomized kidneys (five cases of renal cell carcinoma, one case of lipofibrosarcoma, and six cases of kidney transplant donors). In these four groups, ET-1 and vWF showed equally positive staining in small arteries. VWF also showed positive staining in arterioles and peritubular capillaries in all groups. Although the glomeruli showed positive staining with ET-1 along the capillary walls in the normal group and the nonpregnant nephrotic group, they showed very weak or negative results in the preeclamptic group. Moreover, gravida with underlying glomerular disease without superimposed preeclampsia also showed negative findings of ET-1 in the glomeruli. The glomeruli in the four groups showed positive findings, with vWF readings the same as in the controls. These results indicate that the production of ET-1 in the glomerular endothelial cells decreases in cases of both preeclampsia and normal pregnancy, and the condition may be caused by pregnancy itself.

Adult↗
PubMed1997

Isolated 3-methylcrotonyl-CoA carboxylase deficiency in a 15-year-old girl.

A 15-year-old girl with a former clinical diagnosis of cerebral palsy was found to have isolated deficiency of 3-methylcrotonyl-CoA carboxylase (MCC) on gas chromatography-mass spectrometry (GC/MS) analysis and enzyme determination. Her symptoms included marked growth retardation from birth, profound mental retardation, tonic seizures, rigospastic quadriplegia with opisthotonic dystonia, gastroesophageal reflux with poor esophageal peristalsis, and recurrent episodes of aspiration pneumonia. Brain MRI revealed marked brain atrophy, involving both the gray and white matter. Although she did not exhibit acute metabolic decompensation or acute encephalopathy, her neurological symptoms continuously worsened. This patient is the oldest among reported cases of MCC deficiency who had symptoms at birth, and this case may have the severest sequelae of the longest known natural course of this inborn error of metabolism.

Adolescent↗
PubMed1997

Plasma angiotensinogen concentrations in obese patients.

A close relationship between obesity and hypertension has been recognized, and plasma angiotensinogen concentrations (p-AGT) have been reported to correlate with blood pressure (BP). However, little is known about AGT in obese patients with hypertension. To define the role of AGT in obese hypertension, we measured p-AGT in obese patients. The subjects were 42 obese patients diagnosed on the basis of a body mass index (BMI) of more than 25 kg/m2, and 21 sex- and age-matched nonobese patients, whose BMI was less than 25 kg/m2. The hypertensive patients had not previously received antihypertensive drugs. P-AGT (P < .05) and mean BP (P < .0001) was increased in the obese patients as compared with the nonobese patients. Positive correlations were observed between BMI and p-AGT, mean BP and p-AGT, and BMI and mean BP (all P < .05). However, after adjustment for blood pressure, p-AGT was not different between groups, and after adjustment a positive correlation remained only between BMI and mean BP. These results suggested the possible involvement of increased p-AGT in hypertension in obese patients, although this may be a secondary change to hypertension or obesity.

Adult↗
PubMed1997

Stimulatory effect of gangliosides on phagocytosis, phagosome-lysosome fusion, and intracellular signal transduction system by human polymorphonuclear leukocytes.

Gangliosides are known to be differentiation-inducing molecules in mammalian stem cells. We studied the interaction between the molecular structure of glycosphingolipids (GSLs) and their promoting mechanisms of the phagocytic processes in human polymorphonuclear leukocytes (PMN). The effect of various gangliosides from mammalian tissues on adhesion, phagocytosis, phagosome-lysosome (P-L) fusion and superoxide anion production was examined by human PMN using heat-killed cells of Staphylococcus aureus-coated with GSLs. Gangliosides GM3, GD1a, GD3 and GT1b showed a marked stimulatory effect on the phagocytosis and P-L fusion in a dose-dependent manner, while ganglioside GM1, asialo GM1 and neutral GSLs did not. The relative phagocytic rate of ganglioside GM3-coated S. aureus was the highest among the tested GSLs. Both P-L fusion rate and phagocytosis of S. aureus were elevated significantly when coated with ganglioside GD1a, GD3 or GT1b, and GT1b gave a five times higher rate than that of the non-coated control. These results suggest that the terminal sialic acid moiety is essential for the enhancement of phagocytosis and that the number of sialic acid molecules in the ganglioside is related to the enhancement of the P-L fusion process. On the other hand, the superoxide anion release from PMN was not affected by ganglioside GM2, GM3, GD1a or GT1b. Furthermore, to clarify the trigger or the signal transduction mechanism of phagocytic processes, we examined the effect of protein kinase inhibitors such as H-7, staurosporine (protein kinase C inhibitor), H-89 (protein kinase A inhibitor), genistein (tyrosine kinase inhibitor), ML-7 (myosin light chain kinase inhibitor), and KN-62 (Ca2+/calmodulin-dependent protein kinase II inhibitor) on ganglioside-induced phagocytosis. H-7, staurosporine and KN-62 inhibited ganglioside-induced phagocytosis in the range of concentration without cell damage, while H-89, genistein and ML-7 did not. Moreover, H-7 and KN-62 inhibited ganglioside-induced P-L fusion. These results suggest that protein kinase C and Ca2+/calmodulin-dependent protein kinase II may be involved in the induction of phagocytosis and P-L fusion stimulated by gangliosides.

Bacterial Adhesion↗
PubMed1997

Distribution of alpha 1B-adrenergic receptor mRNA expression along rat nephron segments.

Although several alpha-adrenergic receptor genes are expressed in the rat kidney, little information is available on their expression in the renal nephron segments. We investigated the distribution of alpha 1B-adrenergic receptor mRNA in rat nephron segments using reverse transcription and polymerase chain reaction (RT-PCR). The nephron segments of six- to eight-week-old male Sprague-Dawley rats were microdissected. Total RNA was prepared by the acid-guanidinium-phenol-chloroform method and used in the following RT-PCR assay. The PCR products were size-fractionated with electrophoresis, visualized with ethidium bromide staining and confirmed by Southern blot analysis. Because the PCR primers spanned an intron, the amplification product of the predicted size was considered to be from alpha 1B-adrenergic receptor cDNA and not from genomic DNA. The PCR products were detected in glomerulus (Glm), proximal convoluted and straight tubules (PCT, PST) and cortical and medullary thick ascending limbs of Henle (CTAL, MTAL). No signals were detected in cortical or medullary collecting ducts (CCD, MCD). Large signals were detected in the PCT, and PST, while small signals were found in the Glm, CTAL and MTAL. The alpha 1B-adrenergic receptor mRNA was detected for the first time in rat Glm, PCT, PST and TAL using RT-PCR. alpha 1BAR mRNA seems to be expressed in the specific sites along the nephron and may play significant roles in renal functions, although the specific physiological effects of the renal alpha 1B-adrenergic receptor are unknown.

Animals↗
PubMed1997

Possible mechanisms underlying the midazolam-induced relaxation of the noradrenaline-contraction in rabbit mesenteric resistance artery.

1. The mechanisms underlying the midazolam-induced relaxation of the noradrenaline (NA)-contraction were studied by measuring membrane potential, isometric force and intracellular concentration of Ca2+ ([Ca2+]i) in endothelium-denuded muscle strips from the rabbit mesenteric resistance artery. The actions of midazolam were compared with those of nicardipine, an L-type Ca2+-channel blocker. 2. Midazolam (30 and 100 microM) did not modify either the resting membrane potential or the membrane depolarization induced by 10 microM NA. 3. NA (10 microM) produced a phasic, followed by a tonic increase in both [Ca2+]i and force. Midazolam (10-100 microM) did not modify the resting [Ca2+]i, but attenuated the NA-induced phasic and tonic increases in [Ca2+]i and force, in a concentration-dependent manner. In contrast, nicardipine (0.3 microM) attenuated the NA-induced tonic, but not phasic, increases in [Ca2+]i and force. 4. In Ca2+-free solution containing 2 mM EGTA, NA (10 microM) transiently increased [Ca2+]i and force. Midazolam (10-100 microM), but not nicardipine (0.3 microM), attenuated this NA-induced increase in [Ca2+]i and force, in a concentration-dependent manner. However, midazolam (10 and 30 microM), had no effect on the increases in [Ca2+]i and force induced by 10 mM caffeine. 5. In ryanodine-treated strips, which have functionally lost the NA-sensitive Ca2+ storage sites, NA slowly increased [Ca2+]i and force. Nicardipine (0.3 microM) did not modify the resting [Ca2+]i but partly attenuated the NA-induced increases in [Ca2+]i and force. In the presence of nicardipine, midazolam (100 microM) lowered the resting [Ca2+]i and further attenuated the remaining NA-induced increases in [Ca2+]i and force. 6. The [Ca2+]i-force relationship was obtained in ryanodine-treated strips by the application of ascending concentrations of Ca2+ (0.16-2.6 mM) in Ca2+-free solution containing 100 mM K+. NA (10 microM) shifted the [Ca2+]i-force relationship to the left and enhanced the maximum Ca2+-induced force. Under these conditions, whether in the presence or absence of 10 microM NA, midazolam (10 and 30 microM) attenuated the increases in [Ca2+]i and force induced by Ca2+ without changing the [Ca2+]i-force relationship. 7. It was concluded that, in smooth muscle of the rabbit mesenteric resistance artery, midazolam inhibits the NA-induced contraction through its inhibitory action on NA-induced Ca2+ mobilization. Midazolam attenuates NA-induced Ca2+ influx via its inhibition of both nicardipine-sensitive and -insensitive pathways. Furthermore, midazolam attenuates the NA-induced release of Ca2+ from the storage sites. This effect contributes to the midazolam-induced inhibition of the NA-induced phasic contraction.

Animals↗
PubMed1997

Overexpression of tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma by bone marrow cells from patients with myelodysplastic syndromes.

To clarify whether regulatory cytokines inhibit hematopoiesis in patients with myelodysplastic syndromes (MDS), malignancies characterized by the formation of cytopenias despite the presence of cellular bone marrow, expression of TNF-alpha and IFN-gamma by bone marrow cells was investigated using specific reverse transcriptase-polymerase chain reaction assays. An enhanced expression of the mRNA for TNF-alpha was observed in most of the samples from MDS patients (11/14, 79%), whereas no enhancement was observed in bone marrow samples from AML (0/6), CML (0/2) or control cases (0/8). The expression of IFN-gamma was also enhanced in some of MDS cases (5/12, 42%) while AML (0/5), CML (0/2) and control cases (0/6) showed very low levels of IFN-gamma mRNA expression. Immunohistochemical examination confirmed the scattered presence of TNF-alpha or IFN-gamma producing cells in the bone marrow of MDS patients. The majority of these cells were CD68-positive macrophage lineage cells. These results suggested that disruption of hematopoiesis in MDS might be caused by enhanced production of inhibitory regulatory cytokines especially TNF-alpha and occasionally IFN-gamma by bone marrow macrophages.

Adult↗