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Biomedical subjects

H Iida

Publications and source records attributed to H Iida.

At least 307 records · Page 17Linked to original sources
PubMed1993

Effect of Clostridium perfringens epsilon toxin on rat isolated aorta.

The effect of Clostridium perfringens epsilon toxin on rat isolated aorta was investigated. The toxin caused contraction of the isolated aorta in a dose-dependent manner. The toxin induced no contraction of the isolated aorta in low-Na medium and of the tissue stored at 4 C for 7 days. However, tetrodotoxin (TTX) had no effect on the toxin-induced contraction. The toxin-induced contraction was significantly inhibited by phentolamine and prazosin, but did not by atropine, mecamylamine, chlorpheniramine and methysergide. These data suggest that the toxin-caused contraction is mediated through nervous system in rat isolated aorta.

Animals↗
PubMed1993

Fetal responses to acute maternal cocaine injection in sheep.

Maternal cocaine abuse has been associated with neonatal neurological and neurobehavioral problems of unknown pathogenesis. We administered a single intravenous dose of cocaine (2 mg/kg) to 12 unanesthetized pregnant sheep; their fetuses had been catheterized in utero 2 days before the study. We measured fetal cerebral blood flow (CBF), cerebral metabolic rate of O2 (CMRO2), mean arterial blood pressure (MAP), and blood gases before and 2, 5, 15, and 30 min after maternal cocaine injection. Fetal CBF increased by 37 +/- 33% (mean +/- SD) at 5 min and returned to baseline by 15 min. Regional brain blood flow changes paralleled CBF changes with the greatest increases occurring in cerebellum (54 +/- 43%) and brain stem (54 +/- 52%). Cerebral vascular resistance was decreased for cerebellum (22%) and brain stem (19%) but was unchanged for cerebral hemispheres and caudate. Increased CBF at 5 min was associated with a 20 +/- 9% increase in fetal MAP and a 38 +/- 13% decrease in fetal arterial O2 content. Fetal CMRO2 was unchanged. There was a decrease in fetal intestinal blood flow at 2 min, an increase in myocardial, adrenal, and renal blood flow at 5 min, and no change in placental blood flow. Maternal cocaine injection causes fetal hypoxemia, hypertension, and increased CBF. Possible mechanisms for cerebral vasodilation (in some areas) include hypoxemia, impaired autoregulatory response to increased blood pressure, and/or direct or indirect vascular effects of cocaine or its metabolites.

Animals↗
PubMed1993

Effect of a novel immunosuppressant, FK506, on spontaneous lupus nephritis in MRL/MpJ-lpr/lpr mice.

We evaluated the effect of the novel immunosuppressive agent, FK506, which is known to inhibit T cell immunity, on the development of lupus nephritis in MRL/MpJ-lpr/lpr (MRL/l) mice. FK506 was administered subcutaneously (1 mg/kg body weight) from 12 to 20 weeks of age in 13 MRL/l mice with spontaneous lupus nephritis. Nine animals receiving no treatment were used as the control. FK506 significantly reduced the development of proteinuria, lowered the level of BUN, and suppressed the elevation of serum anti-dsDNA antibodies. Histopathological study showed that FK506 significantly inhibited the progression of glomerular hypercellularity and crescent formation. Glomerular deposition of C3 was significantly reduced in the FK506-treated mice compared to the nontreated controls. These findings suggest that FK506 may protect against progression of lupus nephritis in MRL/l mice, an animal model of systemic lupus erythematosus.

Animals↗
PubMed1993

Localization of gap junction proteins, connexins 32 and 26, in rat and guinea pig liver as revealed by quick-freeze, deep-etch immunoelectron microscopy.

By use of site-specific antibodies against synthetic oligopeptides, we examined the localizations of the gap junction proteins connexin 32 (Cx32) and connexin 26 (Cx26) in rat and guinea pig liver. Double-labeling immunofluorescence microscopy revealed that in guinea pig liver both proteins were spread throughout the liver lobules and seemed to localize together within the same gap junction plaque. In rat liver, co-localization of both Cx32 and Cx26 in the same plaques was also suggested in periportal zones. Quick-freeze, deep-etch immunoelectron microscopy showed that immunolabeling of isolated guinea pig liver gap junction plaques with either Cx32 or Cx26 antiserum yielded complete and dense antibody decoration of the cytoplasmic surface of the plaques. In isolated rat liver plaques, the cytoplasmic surfaces were densely decorated with Cx32 antiserum, whereas Cx26 labeling yielded diffuse decoration with variable intensity of the plaques. In both species we did not observe any focal or patchy clusters of the labeling in any plaques examined. Double-labeling immunoelectron microscopy confirmed that both Cx32 and Cx26 are co-localized in the same gap junction plaques. These results suggest that in hepatocytes expressing both Cx32 and Cx26, both types of gap junction proteins are not segregated but intermingle randomly within the same plaques.

Amino Acid Sequence↗
PubMed1993

Histomorphometric changes in iliac trabecular bone during pregnancy and lactation in beagle dogs.

Changes in bone metabolism throughout pregnancy and lactation in female beagle dogs were examined by histomorphometry and measurement of serum biochemical constituents related to bone. A total of eight dogs, including one dog observed repeatedly from 1 year and 8 months to 4 years and 7 months of age, were used. For double bone labeling to obtain the bone dynamic parameters, dogs were each injected twice, at an interval of 7 days, with fluorochromes such as tetracycline or calcein at the time just after mating, just after delivery, and before weaning. At the time just after weaning, the iliac bone was biopsied. Histomorphometric analysis of trabecular bone area of undecalcified iliac bone sections was performed using a semiautomatic image analyzer. Serum biochemical parameters related to bone such as parathyroid hormone, calcitonin, calcium, phosphorus and alkaline phosphatase activity were periodically measured. Bone histomorphometric analysis revealed significant increases in the mean values of osteoid volume and mineral apposition rate as compared with those of age-matched no pregnancy dogs. The mineral apposition rate measured with the passage of time was increased after delivery and was further increased before weaning compared with that at the time of mating. There were no significant changes in mean values of bone volume, mean trabecular thickness, bone formation rate and mineralizing lag time.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1993

[Age-related changes in bone weights and their components in rats].

Age-related changes in the wet, dry and ash weights and components such as water, organic substance, ash, calcium and phosphorus of femur, tibia and first lumbar vertebra and serum biochemical constituents related to bone metabolism were examined in Wistar rats. A total of 60 males and 60 females were used, and every five rats of both sexes were examined at 1 and 2 months of age and then at intervals of 3 months between 3 and 30 months of age. Each bone weight increased rapidly up to 3 months of age and then gradually up to 12 months of age in females and 9 months of age in males, but thereafter decreased at 27 and 30 months of age in males. Between 1 and 6 or 9 months of age in both sexes, a decrease in water content, increases in ash, calcium and phosphorus, and almost no change in organic substance in each bone were observed. After 15 months of age in males, an increase in water content, decreases in ash content, calcium and phosphorus, and almost no changes in organic substance were observed in males. The value of serum calcium decreased up to 12 months of age but then increased after 18 months of age in both sexes. Serum phosphorus and alkaline phosphatase activity decreased up to 9 months of age in both sexes. The data obtained in this study supported the results in our previous study that the peak bone strength of the femur and peak bone volume of trabecular bone of the proximal metaphysis of the tibia were at 12 months of age in both sexes in Wistar rats.

Aging↗
PubMed1993

Glomerulosclerosis in the rat induced by repeated immune-mediated mesangial cell injury.

Glomerulosclerosis is a common feature of progressive glomerular injury. We investigated whether experimental glomerulosclerosis could be induced by repeated immunologic injury to mesangial cells. Chronic mesangial proliferative glomerulonephritis (GN) was induced by repeated injections of polyclonal antibody directed against the Thy 1 antigen present on the mesangial cell membrane. An intravenous injection of anti-Thy 1 serum (ATS) was given weekly to 18 male Wistar rats, which were sacrificed at weeks 2, 4 and 6 after induction of GN. Blood urea nitrogen and serum creatinine were significantly elevated in rats with anti-Thy 1 nephritis at weeks 4 and 6 compared to normal rats. Progressive expansion of the mesangial matrix with diffuse sclerosis was observed at weeks 4 and 6 by silver methenamine staining. Ultrastructurally there was a prominent rough endoplasmic reticulum in the mesangial cells and collagenous fibrils in an expanded mesangial matrix. Immunohistochemical staining revealed a marked increase in type IV collagen and laminin in the mesangium at weeks 4 and 6. Thus, repeated immunologic injury restricted to the mesangium may result in the accumulation of extracellular matrix and the development of glomerulosclerosis. These studies emphasize the importance of the mesangial cell in progressive glomerular injury.

Animals↗
PubMed1993

[A case of hypertrophic obstructive cardiomyopathy with marked T wave changes during the short-term].

A 72-years-old woman was admitted to our hospital for evaluation of giant negative T waves, which appeared for only two days. Chest X-p revealed a cardiomegaly of slight degree and UCG showed ASH (IVS = 21 mm). Coronary arteriography presented no significant stenosis and the left ventricle was spade-shaped. There was a pressure gradient of 65 mmHg between the aorta and the left ventricle during isoproterenol infusion. Furthermore, endomyocardial biopsy showed disarray and fibrosis to a slight degree and fatty degeneration of myocytes with contraction bands. Based on these findings, calcium blocker was administrated under the diagnosis of HOCM. One month after the initiation of this drug, negative T waves gradually became shallow and finally upright with thinning of IVS (12 mm) four month later. We swimise that this T-wave change is primarily based on myocardial hypertrophy as well as being due to the abnormality of myocardial depolarization. We presented a case of HOCM with negative T-wave change of very short duration, which was improved by calcium-blocker and beta-blocker.

Adrenergic beta-Antagonists↗
PubMed1993

[A new method for quantitative measurement of rCBF using graphic plot analysis: application to 123I-IMP dynamic study].

To estimate regional cerebral blood flow (rCBF) using the dynamic data, a new graphic plot analysis is proposed. By assuming a two-compartment model for the tracer kinetics, we derived the linear relationship as Y(t) = 1/K1 + theta t, where Y(t) is the ratio of time-integrated blood activity to brain tissue activity, t is the scan time, and theta is a proportional constant. A plot of Y(t) against the scan time t yields a straight line and the y-intercept of the line represents the value of inverse rCBF K1. This method was applied to five normal subjects with N-isopropyl-p(123I)iodoamphetamine. The mean value of K1 in the gray matter was 42.1 +/- 6.8 ml/100 g/min. We also produced the rCBF images within a few seconds using the present method. The present graphical method gives a reliable and rapid estimation of rCBF.

Amphetamines↗
PubMed1993

Modeling approach to eliminate the need to separate arterial plasma in oxygen-15 inhalation positron emission tomography.

A mathematical model has been developed to predict the arterial metabolite concentration curve using the whole blood radioactivity curve in positron emission tomography (PET) during 15O2 inhalation. Production of arterial H2 15O due to aerobic metabolism in the body was modeled as a single rate constant, which was determined from 200 steady-state values of plasma and whole blood concentrations recorded during continuous inhalation of 15O2 and C15O2. Comparison of this method in eight 15O2 inhalation studies (four at rest and four during motor stimulation) performed on four subjects resulted in: (1) arterial H2 15O curves that were well matched in shape to those measured by the frequent plasma separation and (2) cerebral metabolic rate of oxygen (CMRO2) and cerebral blood flow (CBF) were consistent with those obtained by the frequent plasma separation procedure (maximum difference was 3%). An error sensitivity analysis was also performed and demonstrated that errors expected in this modeling approach caused only negligible errors in CMRO2 and CBF estimates. Thus, the arterial H2 15O concentration curve can be accurately predicted using the whole blood time-activity curve; hence, plasma separation can be avoided in 15O2 inhalation PET.

Administration, Inhalation↗
PubMed1993

[A case of pulmonary solitary metastasis of renal cell carcinoma nine years after radical nephrectomy].

A 65-year-old woman was admitted to our department when a routine screening chest X-ray film demonstrated pulmonary solitary nodule. Nine years before, left nephrectomy had been performed with a diagnosis of renal cell carcinoma, and postoperative course was uneventful. Chest X-ray and CT confirmed the presence of well-circumscribed mass in the right lower lobe of lung. With a presumptive diagnosis of pulmonary metastasis of renal cell carcinoma, right lower lobectomy and resection of mediastinal lymph nodes was performed. The pathological diagnosis was metastasis of renal cell carcinoma, granular cell subtype. Pulmonary solitary metastasis of renal cell carcinoma, especially nine years after radical nephrectomy is rare case.

Aged↗
PubMed1993

A new graphic plot analysis for cerebral blood flow and partition coefficient with iodine-123-iodoamphetamine and dynamic SPECT validation studies using oxygen-15-water and PET.

To estimate regional cerebral blood flow (rCBF) and brain-blood partition coefficient (lambda) using a dynamic measurement, a new graphic plot analysis is proposed. By assuming a two-compartment model for tracer kinetics, we derived the linear relationship as Y(t) = K1 - k2 X(t), where Y(t) is the ratio of brain tissue activity-to-time-integrated arterial blood activity and X(t) is the ratio of time-integrated brain tissue activity-to-time-integrated arterial blood activity. A plot of Y(t) against X(t) yields a straight line and the y- and x-intercept of the regression line represent rCBF (K1) and lambda, respectively. The slope is a washout constant (-k2). This method was applied to 14 subjects with N-isopropyl-p-iodine-123 iodoamphetamine ([123I]IMP). The mean values of K1 and lambda for normal subjects were 41.3 +/- 6.7 ml/100 g/min and 29.6 +/- 6.5 ml/g, respectively, in the gray matter. A comparative study with positron emission tomography (PET) using an H2(15)O autoradiographic method revealed good correlation between IMP K1 and PET rCBF [r = 0.822; K1 = 0.842 rCBF + 0.030 (ml/g/min)]. The values of K1 using the graphical method were in excellent agreement with those using a nonlinear least-squares fitting technique (r = 0.992 for K1; r = 0.941 for lambda). The estimated K1 values in the graphical method were not changed when scanning times were varied. We conclude that a two-compartment model is acceptable for IMP kinetics within a scan time of 60 min. The graphical method gives a reliable and rapid estimation of rCBF when applied to dynamic data.

Amphetamines↗
PubMed1993

[A technique for a rapid imaging of regional CBF and partition coefficient using dynamic SPECT and N-isopropyl-p-[123I]iodoamphetamine (123I-IMP)].

IMP is a flow tracer due to a large first pass extraction fraction and high affinity in the brain, but significant clearance from the brain causes change of distribution when the scan start time is delayed. The purpose of the present study is to develop a new method to rapidly calculate a quantitative CBF image by taking into account for the clearance effects. A dynamic SPECT scan was performed on 5 subjects (4 patients with cerebral infarction and 1 normal volunteer) following slow intravenous infusion of 123I-IMP. The arterial input function was obtained by frequent blood sampling and by measuring an octanol extraction ratio for each sample. Firstly, non-linear least square fitting (NLS) was performed to investigate the tracer kinetics of 123I-IMP. The 3 compartment model analysis yielded negligibly small k3 (retaining rate constant) (0.0056 +/- 0.0128 (ml/ml/min)), and consistent k1 (transport rate constant) with those determined by 2 compartment model (2CM) analysis (r = 0.96, p < 0.001). In addition, k1 was consistent with CBF measured by 15O water PET technique. These observations suggested validity of using 2CM for describing the IMP tracer kinetics. Secondly, a weighted integration (WI) technique has been implemented to calculate rapidly images of CBF and partition coefficient (Vd). The WI technique yielded values of CBF (k1) and Vd (k1/k2). They were confirmed to be consistent with those determined by NLS technique (CBF; r = 0.99, p < 0.001, Vd; r = 0.99, p < 0.001), and calculated k1 agreed well with PET CBF (r = 0.91, p < 0.001). We observed changed Vd in infarcted patients. This supports an importance for calculating of Vd image. Vd image will provide additional clinical information because 123I-IMP binding mechanism may be related to cell viability.

Adult↗
PubMed1993

Cytoplasmic surface ultrastructures of gap junctions in bovine lens fibers.

PURPOSE: To examine the cytoplasmic surface ultrastructures of lens fiber gap junctions, where the cytoplasmic domains of connexons were expected to be exposed. METHODS: Bovine lens fiber gap junctions, both in situ and in the form of isolated membranes, were examined with the deep etching replica methods. Isolated membranes were also examined with the same methods after the treatment with endoproteinase glu-C, which is known to cleave off the cytoplasmic domain of a putative lens fiber connexin MP70 to determine whether any structural changes should occur between proteolyzed and nonproteolyzed gap junctions. In addition, both proteolyzed and nonproteolyzed gap junctions were studied by sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunolabeling with the monoclonal antibody that recognized cytoplasmic domain of MP70 to clarify whether MP70 lost its cytoplasmic domain by the treatment with endoproteinase glu-C. RESULTS: Gap junctions were shown to have particulate substructures on their cytoplasmic surfaces; the distributions of the particles were restricted within gap junctional plaques and the non-gap-junctional areas showed smooth cytoplasmic surfaces. Although the treatment with endoproteinase glu-C failed to remove the cytoplasmic particles of gap junctions in deep etching replica study, MP70 was shown to have lost its cytoplasmic domain in sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunolabeling studies. CONCLUSIONS: Each particle revealed on the cytoplasmic surfaces of lens fiber gap junctions corresponded to the cytoplasmic domain of a connexon. The particles were not removed by the treatment with endoproteinase glu-C, whereas MP70 was cleaved by the same treatment.

Animals↗
PubMed1993

Regression of vascular structural changes and calcium metabolism in patients with essential hypertension after long-term monotherapy with enalapril.

We investigated the effect of one year of enalapril monotherapy on vascular structural changes and calcium metabolism in ten patients with essential hypertension. BP decreased from 169-10/103 +/- 10 mmHg during the placebo period to 138-12/82 +/- 10 mmHg after enalapril therapy. Minimal vascular resistance assessed by the venous occlusion technique with strain-gauge plethysmography was higher in the hypertensive patients than in the normotensive subjects (2.7 +/- 1.2 vs. 1.2 +/- 0.3 mmHg/ml/min per 100 ml tissue, P < 0.01). Although the elevated minimal vascular resistance seen in essential hypertensives decreased to 1.7 +/- 0.5 mmHg/ml/min per 100 ml tissue after enalapril (P < 0.01), it remained higher than that of normotensives (P < 0.05). Cytosolic free calcium ([Ca2+]i) in platelets measured by a Qiun-2 fluorescent indicator was higher in essential hypertensives than in normotensives (189 +/- 38 nM and 138 +/- 14 nM, respectively; P < 0.01). [Ca2+]i of essential hypertensives was reduced to 138 +/- 19 nM after treatment. Plasma renin activity was significantly increased after enalapril. Although plasma ionized calcium concentration did not change, parathyroid hormone was significantly increased after enalapril (from 0.36 +/- 0.22 to 0.58-0.32 ng/ml, P < 0.05). During the placebo period, minimal vascular resistance was correlated with [Ca2+]i (r = 0.62, P < 0.01). There was a close relationship between the changes in minimal vascular resistance and [Ca2+]i (r = 0.78, P < 0.01); however the change in minimal vascular resistance was not associated with changes in BP, catecholamine or parathyroid hormone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

The topographical features of EEGs in patients with affective disorders.

EEG data were obtained in the basic state from 16 scalp sites of 44 patients with affective disorder, diagnosed by DSM-III criteria, and 44 normal controls. The EEG power spectra were computed and the t statistic significance probability mapping (SPM) was applied to visualize regions where the patient group showed differences in the EEG topogram from the controls. The results show: (1) left occipital predominance (P3, O1) of alpha activities in the patients with affective disorders, (2) decreased alpha activities in Fp2 and F8 areas in patients with major depression without melancholia, (3) decreased alpha activities in F7 area in patients with bipolar disorder, manic, and (4) increased beta 2 activity in F4 and C4 areas in patients with major depression with melancholia. These results suggest that inter-hemispheric and intra-hemispheric relationships may be disturbed in patients with affective disorder.

Adult↗