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Biomedical subjects

T Iwata

Publications and source records attributed to T Iwata.

At least 217 records · Page 12Linked to original sources
PubMed1993

[A method for measurement of circulating blood volume with fluorescein isothiocyanate labeled red blood cells].

We developed a new method to measure the total circulating blood volume using fluorescein isothiocyanate (FITC) labeled autologous red blood cell as an indicator. Red blood cells were labeled by incubation with 0.1 mg.ml-1 FITC in PBS (pH 7.2) for 30 min at 37 degrees C. Eighteen dogs were given an intravenous injection of FITC labeled red blood cells, which were approximately 0.1% of the total circulating red blood cells estimated from the body weight. The ratio of labeled cells to the normal circulating red blood cells was determined by a flow cytometry. The total blood volume was calculated from its dilution rate. The average circulating blood volume determined by this method was 76.8 +/- 9.2 ml.kg-1 (mean +/- SD). This result coincides well with the values reported previously. This method using non radioactive tracers enables a reproducible measurement of circulating blood volume and its change with time.

Animals↗
PubMed1993

Efficacy of acellular pertussis vaccine in young infants.

A prospective study of a pertussis outbreak in a residential facility was done. Among 19 residents aged < or = 2 years, 10 children were unimmunized and 9 were immunized with acellular pertussis vaccines. Of the 10 unimmunized children, 7 acquired laboratory-confirmed pertussis (four-fold titer rise, positive culture, or both); of these, 6 developed typical symptoms. Eight of the 9 immunized children acquired laboratory-confirmed infections, and 1 of these developed typical symptoms. No difference in infection was noted between the unimmunized and immunized groups (7/10 vs. 8/9, respectively), but a significant difference was observed in the development of symptoms (6/10 vs. 1/9, P < .05). Also, the isolation rate of Bordetella pertussis seemed to differ between the two groups (6/10 vs. 2/9, P = .12). In this population, acellular pertussis vaccine did not prevent infection with B. pertussis but protected most young infants from the onset of clinical symptoms.

Antibodies, Bacterial↗
PubMed1993

Left ventricular cardiac structure and diastolic function in isolated systolic hypertension in the elderly.

We examined the left ventricular cardiac structure and the diastolic function in patients with isolated systolic hypertension (ISH; SBP > or = 160 mmHg and DBP < 90 mmHg) in the elderly. We studied 17 patients with ISH, 24 age-matched patients with essential hypertension (EHT; DBP > or = 90 mmHg) and 17 normotensive controls (NT; SBP < 140 mmHg and DBP < 90 mmHg). EHT were divided into two groups based on the mean wall thickness (MWT) of the left ventricle. Group 1 patients (EHT-I, n = 12) had a MWT < 10 mm and group 2 patients (EHT-II, n = 12) had a MWT > or = 10 mm. We measured left ventricular end-diastolic dimension (LVDd), end-systolic dimensions (LVDs), left ventricular mass index (LVMi) and left ventricular isovolumic relaxation time (IRT) to assess the left ventricular cardiac structure and the diastolic function by M-mode echocardiography. LVDd was significantly smaller in ISH than in NT, EHT-I and EHT-II (P < 0.01). Relative wall thickness was greatest in ISH because of both the decreased chamber size and the increased left ventricular wall thickness. LVMi in ISH was similar to that in EHT-I, but IRT in ISH was significantly longer than that in EHT-I (P < 0.05). These results suggest that ISH in the elderly shows a left ventricular concentric hypertrophy and a severely impaired diastolic function.

Aged↗
PubMed1992

Expression, purification, and properties of the plasma membrane Ca2+ pump and of its N-terminally truncated 105-kDa fragment.

Isoform 4b of the human plasma membrane Ca2+ pump was expressed in COS cells and in the baculovirus system (Sf9 cells). A 105-kDa pump fragment lacking the first two transmembrane domains and the so-called transduction domain was also expressed. The expression level was 2-4 times the background in COS cells and at least 7 times in the baculovirus system. Tests on membranes from both systems showed that the expressed pump was active. The expressed pump and the 105-kDa fragment were isolated from Sf9 cell membranes by calmodulin affinity chromatography. The pump had Ca(2+)-dependent ATPase activity with a calmodulin stimulation factor of 3, formed a La(3+)-stabilized phosphoenzyme, and had a KM (Ca2+) in the presence of calmodulin of about 1 microM. The 105-kDa fragment, assayed by the phosphoenzyme test on COS or Sf9 cell membranes or by ATPase measurements after isolation from Sf9 cells, proved inactive. Laser confocal microscopy on Sf9 cells showed that both the pump and the 105-kDa fragment were apparently associated with the plasma membrane. The expressed pump in COS and Sf9 cells and the endogenous pump in a number of other cell lines had a slower gel mobility (i.e. a higher apparent molecular mass) than the erythrocyte pump.

Amino Acid Sequence↗
PubMed1992

Cell cycle-dependent changes in tissue transglutaminase mRNA levels in bovine endothelial cells.

The pattern of transglutaminase gene expression through the cell cycle was examined by Northern blot analysis using cultured bovine endothelial cells and a cDNA probe. When the cells reached confluency or were arrested in G0/G1 phase by nutrition deprivation, transglutaminase mRNA rose to a very high level; S- and M-phase extracts showed high and low levels, respectively. Subcellular localization studies by sucrose gradient centrifugation and immunostaining demonstrated that the majority of transglutaminase is present in cytosols throughout the cycle. The cell cycle-dependent changes in the transglutaminase mRNA levels strongly support the implicated involvement of the enzyme in cell growth, differentiation, and senescence.

Animals↗
PubMed1992

Microdiversity of human-plasma-membrane calcium-pump isoform 2 generated by alternative RNA splicing in the N-terminal coding region.

cDNA species covering the entire coding sequence of the human homologue of the rat plasma membrane Ca(2+)-ATPase (PMCA) isoform 2 have been isolated and characterized. The deduced amino acid sequence shows 99% identity with that of the rat protein and can be aligned with the latter without gaps except for one 14-amino-acid-residue insert in the region immediately preceding the putative phospholipid-sensitive domain in the human pump. cDNA clones isolated by anchored polymerase-chain reaction revealed additional microheterogeneity in the same N-terminal PMCA2-coding region. Alternative RNA splicing involving a region of 135 nucleotides generates three types of cDNA. One does not contain any of the 135 bp, and the other two contain 42 bp or the entire 135 bp of the optional sequence. Analysis of genomic DNA indicates that this sequence is encoded by three separate exons of 33, 60 and 42 bp. Although each of these exons could be inserted into the mRNA without changing the reading frame, polymerase-chain amplifications using cDNA libraries from several human tissues show that the 33-bp and the 60-bp exons are never independently used during splicing. The unequal distribution of the splice variants suggests tissue-specific regulation of the alternative-splicing pathways and indicates a functional specialization of the encoded isoform subtypes.

Amino Acid Sequence↗
PubMed1992

Pertussis in adults.

A survey was conducted of 89 households in each of which at least one patient with culture-confirmed pertussis had been detected. The source of infection was found to be an adult in 10 (11.2%) of the 89 households, and the rate of secondary attack was 19 (10.3%) of 185. Furthermore, a laboratory study disclosed 17 adults with subclinical pertussis; the subclinical infection rate was 17 (25.0%) of 68. When compared with pertussis in young children, the adult illness was generally less severe and had different clinical features. Adult pertussis showed neither leukocytosis nor lymphocytosis, but it produced anti-pertussis toxin antibody more quickly and higher levels of anti-filamentous hemagglutinin and agglutinin antibodies, and showed stronger growth inhibition of Bordetella pertussis. Although adult pertussis is usually unrecognized because of its different clinical and laboratory features, it is a significant health threat that requires some measures for disease control.

Adult↗
PubMed1992

Daily activity and persistent sleep-wake schedule disorders.

1. Patients with disorders of entrainment to external time cues such as delayed sleep phase syndrome (DSPS) and non-24-hour sleep-wake syndrome (HNS) were treated with non-pharmacological interventions and/or pharmacological agents. 2. Resetting the circadian clock with chronotherapy was easy in all DSPS patients, but it was not as easy to maintain the reset rhythm without additional therapy. Triazolam was effective in treating the phase delay that reappeared after chronotherapy. 3. Vitamin B12 (methylcobalamin) was strikingly effective in some patients with DSPS or HNS. 4. All the adolescent patients who complained of inability to attend school finally returned to their classes after treatment. Maintaining the reset rhythm in adolescent patients was easier than in adults.

Adolescent↗
PubMed1992

Response of plasma renin-angiotensin system to a single captopril administration in patients receiving long-term treatment with captopril.

1. The responses of angiotensin II (AII), AIII, aldosterone and plasma renin activity (PRA) to a single dose of captopril were investigated in hypertensive patients receiving long-term (more than 1 year) captopril therapy (CT patients) and compared with those of non-treated hypertensive patients (NT patients). 2. Baseline levels of AII and aldosterone were significantly lower in CT patients than in NT patients. AIII tended to be lower and PRA was slightly higher in CT than in NT patients, but these differences were not significant. 3. A single administration of captopril (50 mg orally) significantly decreased plasma levels of AII, AIII and aldosterone as well as blood pressure in both CT and NT patients. 4. These results demonstrate that chronically repeated administration of captopril to hypertensive patients effectively reduces the daily blood pressure and concomitantly the plasma AII level to acceptable levels in patients with no experience of ACE inhibition.

Aldosterone↗
PubMed1992

Carrier detection in agammaglobulinemia by X chromosome inactivation analysis.

Using a recently developed strategy to analyze patterns of X chromosome inactivation in cell populations, we found that two mothers and a sister were carriers in three atypical or sporadic cases of patients with agammaglobulinemia, two of whom were brothers. In this study, a phosphoglycerate kinase 1 (PGK1) gene probe was used to detect patterns of methylation of X-chromosome genes. A random pattern of X inactivation was observed in isolated peripheral blood granulocytes. In contrast, one of the two X chromosomes was preferentially active in the Epstein-Barr virus (EBV)-transformed peripheral B cells of the family members of these patients. The volume of the blood specimen could be significantly reduced using EBV-transformed B cell lines which contained multiple clones. The analysis described here can be used to distinguish between X-linked agammaglobulinemia (XLA) and other forms of a- or hypo-gammaglobulinemia as well as to detect the carrier state.

Adolescent↗
PubMed1992

Effect of L-threo-3, 4-dihydroxyphenylserine on orthostatic hypotension in a patient with spinal cord injury.

A 72-year-old female who underwent the extirpation of metastatic intraspinal tumor showed an extremely wide variation of blood pressure with recurrent episodes of syncope due to paroxysmal hypotension. Treatment of the patient with salt supplement and L-threo-3, 4-dihydroxyphenylserine, an exogenous precursor of norepinephrine, markedly improved the syncopal attack as well as the daily activity.

Adenocarcinoma↗
PubMed1992

[A case of "pure" progressive autonomic failure in an elderly male].

A 68-year-old man was admitted to our hospital because of postural hypotension in July 1991. He was also suffering from anhydrosis, urinary disturbances, constipation and impotence. He had not developed signs of Parkinsonism, cerebellar or peripheral neuropathy four years from the onset. Various autonomic function tests showed sympathetic and parasympathetic dysfunction of mainly postganglionic origins. Thus we diagnosed this patient as "pure" progressive autonomic failure ("pure" PAF). "Pure" PAF is a new entity described by Bannister and Oppenheimer in 1982. It shows symptoms of autonomic failure without other neurological disturbances which manifest as Shy-Drager syndrome. Treatment with L-DOPS increased his blood pressure level and attenuated his symptoms due to orthostatic hypotension.

Aged↗
PubMed1992

The effect of dietary safflower phospholipid and soybean phospholipid on plasma and liver lipids in rats fed a hypercholesterolemic diet.

The effect of dietary safflower phospholipid (Saf-PL) and soybean phospholipid (Soy-PL) on plasma, liver, and fecal lipids in rats fed a hypercholesterolemic diet was compared with that of triglyceride mixture (controls). Triglyceride mixture (SP-Oil) of safflower oil and palm oil (8:2) contained almost comparable amounts of linoleic acid to safflower phospholipid or soybean phospholipid. Concentration of total cholesterol in plasma of rats fed the Saf-PL and Soy-PL diets were significantly decreased in comparison with that of the SP-Oil diet. Similarly, both Saf-PL and Soy-PL induced a reduction in the concentration of liver cholesterol compared with SP-Oil; Saf-PL indicated the lowest value. Saf-PL only significantly increased the level of high density lipoprotein (HDL) cholesterol. The level of chylomicron plus very low density lipoprotein (VLDL) cholesterol was lower in rats fed the Saf-PL and Soy-PL diets than that of the SP-Oil diet. The activity of plasma lecithin-cholesterol acyltransferase (LCAT) was increased in rats fed Saf-PL and Soy-PL. Saf-PL and Soy-PL caused an enhanced excretion of fecal neutral steroids, but not acidic steroids compared with SP-Oil. These results suggest that, in addition to soybean phospholipid, safflower phospholipid suppresses the elevation of plasma and liver cholesterol and that this effect may be brought about by inhibiting the absorption of cholesterol in the small intestine.

Animals↗
PubMed1992

The effect of dietary safflower phospholipid on steroids in gastrointestinal tract of rats fed a hypercholesterolemic diet.

The effect of dietary safflower phospholipid (Saf-PL) on the postprandial changes of steroids in the small intestinal and cecal contents was examined in rats fed a hypercholesterolemic diet. The triglyceride mixture (SP-Oil) containing a comparable amount of linoleic acid to Saf-PL was used as a reference fat source. Saf-PL suppressed the elevation of plasma cholesterol levels at all times after meal intake, when compared to SP-Oil. The reduction of plasma cholesterol in rats fed the Saf-PL diet was exclusively observed both in chylomicron plus very low density lipoprotein (VLDL) and low density lipoprotein (LDL) fractions. The rate of gastric emptying was not modified by the Saf-PL diet. The level of neutral steroids in the small intestinal contents was almost comparable in both groups, but in the cecal contents and feces it was significantly higher in rats fed the Saf-PL diet. On the other hand, the level of acidic steroids in the small intestinal contents tended to be higher in rats fed the Saf-PL diet than in those fed the SP-Oil diet, whereas in the cecal contents and feces it was comparable in the two diets. These results suggest that Saf-PL causes the accumulation of neutral steroids in the cecum due to the rapid transit through the small intestine.

Animals↗
PubMed1992

Investigation of suitability of devascularized upper half of the whole stomach as replacement for the esophagus.

One hundred and fifteen patients with esophageal cancer underwent esophageal replacement with the stomach. The patients were divided into group A (52 patients, stomach tube, ante- or retro-sternal route) and group B (54 patients, devascularized upper half of the whole stomach, posterior mediastinal route). The post-operative complications, post operative symptoms and nutritional status were investigated in both groups. Lung complications tended to occur more frequently in group A (28.8% versus 22.2%), showing no significant difference. The incidence of other complications did not show a remarkable difference between either group except for leakage at the site of anastomosis. Major leakage occurred in 11.5% and 5.6%, and minor leakage in 30.8% and 18.5%, respectively. Postprandial fullness, nausea, heart burn and diarrhea were found to be somewhat higher in Group B. Change of oral intake, body weight and other indices of nutritional status were investigated and compared with pre- operative data. The amount of oral intake and levels of serum albumin was higher in group B than in group A between one and 12 months. These results demonstrate the superiority of the devascularized upper half of the whole stomach as an esophageal substitute.

Aged↗
PubMed1992

[Clinical significance of IgG4 antibody determination in children against egg white, milk, soybean and Dermatophagoides farinae].

The measurement of IgE and IgG4 antibodies against egg white, milk, soybean and Dermatophagoides farinae was performed by FAST (fluorescence allergosorbent test) using 21 serum samples obtained from non-allergic children and 160 serum samples from atopic children with bronchial asthma and/or atopic dermatitis. Their antibody levels were evaluated for any association with disease severity and for clinical significance in establishing diagnosis. It was found that children with bronchial asthma showed lower levels of IgE antibodies against egg white, milk and soybean and higher levels of IgE antibodies against Dermatophagoides farinae compared with those of children with atopic dermatitis, while both groups showed higher levels of egg white and milk-specific IgG4 antibodies compared with non-allergic children. These IgE and IgG4 antibody levels revealed a tendency to correlate with disease severity in patients with atopic dermatitis, while this was not observed in patients with bronchial asthma. The contribution percentages of IgG4 antibody determination, together with IgE antibody determination, in retrieving causal allergens were 71% for egg white, 70% for milk and 48% for soybean allergy, implying their diagnostic value in establishing clinical diagnosis.

Adolescent↗
PubMed1992

Regulation of the gene expression of type-1 angiotensin II receptor in spontaneously hypertensive rats.

Regulation of the gene expression of type-1 angiotensin II receptor (AT1) by treatment with manidipine, a calcium channel blocker, or delapril, an angiotensin converting enzyme inhibitor, for one week was assessed in the adrenal gland, heart, kidney, and brain from spontaneously hypertensive rats (SHR). Tissue AT1 receptor messenger RNA (mRNA) content was measured by reverse transcriptase-polymerase chain reaction. Treatment with manidipine (3 mg/kg/day) or delapril (30 mg/kg/day) lowered systolic blood pressure (SBP) significantly (p < 0.01) (delta SBP; -73 mmHg or -67 mmHg, respectively). Although delapril markedly increased plasma renin activity (PRA), manidipine did not alter PRA. AT1 receptor mRNA content in the adrenal gland was significantly (p < 0.01) decreased by treatment with manidipine or delapril. In contrast, cardiac AT1 receptor mRNA content was significantly (p < 0.01) increased by treatment with either agent. There was no significant change in renal and brain AT1 receptor mRNA contents. These findings suggest that although the expression of AT1 receptor gene depends on the circulating renin-angiotensin system (RAS), it is regulated independently in a tissue-specific manner via the local RAS in each tissue of SHR.

Adrenal Glands↗