Biomedical subjects

Y Imai

Publications and source records attributed to Y Imai.

At least 253 records · Page 14Linked to original sources

PubMed1999

Small hyperechoic nodules in chronic liver diseases include hepatocellular carcinomas with low cyclin D1 and Ki-67 expression.

In spite of the importance of periodic screening for hepatocellular carcinoma (HCC) by ultrasonography (US) in patients with underlying liver disease, the clinicopathological characteristics of hyperechoic nodules have not been clearly evaluated. The aim of this study was to characterize the pathological and proliferating features of small hyperechoic nodules. Tissue specimens of 55 hyperechoic and 107 hypoechoic nodules less than 20 mm in diameter in patients with chronic liver disease were obtained by echo-guided needle biopsy and examined histopathologically. Of these, 42 (76%) hyperechoic and 56 (52%) hypoechoic nodules were diagnosed as HCC, and 82% of hyperechoic HCCs contained fatty change and/or clear cell change. In addition, immunohistochemical staining using cyclin D1, p53, and Ki-67 was examined. A high-level expression of cyclin D1 was found in only 5% of hyperechoic HCCs, in contrast to 38% of hypoechoic HCCs (P <.02). The labeling index of Ki-67 in hyperechoic HCCs was lower than in hypoechoic HCCs (4.2% vs. 8.9%; P <.003). However, there was no difference on p53 staining between them. Retrospective follow-up study revealed that hyperechoic nodules showed slow growth (doubling time, median: 1,403 days) initially, and came to show rapid growth (doubling time, median: 56 days). From these results, small hyperechoic nodules in chronic liver diseases are worth notice as candidates for well-differentiated HCC with low cyclin D1 and Ki-67 expression.

Adult↗

PubMed1999

Regulation of initiation of Bacillus subtilis chromosome replication.

Bacterial chromosome replication is tightly regulated at the initiation stage to coordinate with mass increase. Together with chromosome partition at cell division, this regulation mechanism ensures the proper number of chromosomes in daughter cells at any growth rate. Therefore, elucidation of this regulation mechanism is important for understanding the bacterial cell cycle. Despite much effort in Escherichia coli and Bacillus subtilis for many years, the mechanism remains to be completely elucidated. In E. coli, it is proposed that a critical amount of DnaA protein determines the time of initiation of replication in the cell cycle. Our study strongly suggested that this might not be the case in B. subtilis. Recently, remarkable progress has been made in bacterial cytology. The new techniques enable us to examine the subcellular location of proteins of interest and DNA regions of the chromosome (for example, the replication origin) and, therefore, to determine directly when in the cell division cycle and where within the cell initiation of chromosome replication takes place. Using the techniques, we detected the initiation complex by examining subcellular location of several Dna-initiation proteins in B. subtilis. Based on our new findings, we propose a novel model for regulation of the time of initiation of chromosome replication in the cell cycle.

Bacillus subtilis↗

PubMed1999

Are Metallic Markers Necessary for Coronary Artery Bypass Grafts? A Study Using X-ray Computed Tomography and Selective Graft Angiography.

Using X-ray computed tomography (CT) and selective graft angiography, the authors studied the necessity of metallic markers in coronary artery bypass grafts on 45 patients (mean age 57.2 years) with 87 saphenous vein grafts. Eight patients had 17 markers. X-ray CT was performed after surgery using an apparatus with a 1-second scanning time. Noncontrast X-ray CT was performed on horizontal sections, at 5-mm intervals, from the lower margin of the aortic arch to the lower left ventricle. A contrast medium was then injected into the antecubital vein (3 ml/second, total 30 ml) in one cross-section at the level of bifurcation of the pulmonary artery. Aortography (60 degrees in the left anterior and oblique positions, 20 ml/second, total 40 ml) was performed concurrently. Selective graft angiography was taken in the same direction, using 4 cm right of the Judkins with reference to the aortographic image and position of five clips on the sternum. Aortography revealed 79 patent and 8 occluded grafts. Selective graft angiography was easily performed even in grafts without markers. A cross-section of the occluded graft could not be seen with X-ray CT. Grafts with markers were often masked by artifacts produced by markers on X-ray CT. The number of observed graft slices (marker-positive grafts) was only 1.2 +/- 1.1 slices, significantly (p < 0.01) lower than marker-negative grafts (4.1 +/- 3.1 slices). In particular, the number of marker-positive right coronary artery grafts was 0.4 +/- 0.9 slices. Four of five right coronary artery grafts were unobservable due to artifacts. In grafts without markers, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of X-ray CT to graft patency were 100%, 85.7%, 98.4%, 100%, and 98.6%, respectively. This study suggests that metallic markers may not be necessary for coronary artery bypass grafts.

Journal Article↗

PubMed1999

Oral clonidine reduces the requirement of prostaglandin E1 for induced hypotension.

PURPOSE: To determine the effects of preanesthetic oral clonidine on the dose of prostaglandin EI (PGEI) required to produce hypotension during anesthesia. METHOD: Oral placebo, 75 microg or 150 microg clonidine were administered 60 min prior to induction of anesthesia. Anesthesia was maintained with O2:N2O (30:70) and isoflurane 1.0%. After hemodynamic stabilization, an infusion of prostaglandin EI was started (0.05 microg x kg(-1) x min(-1)) and the rate of infusion was adjusted to maintain mean arterial pressure (MAP) between 60-70 mm Hg during operation. RESULTS: Duration of hypotension in placebo, 75 microg and 150 microg preanesthetic oral clonidine treated groups were 132+/-46, 117+/-37 and 129+/-56 min, respectively. The PGEI requirement in each group were 1563+/-180 (28.6+/-3.2), 594+/-197 (10.8+/-3.6) and 283+/-30 (5.5+/-3.6) microg (microg x kg(-1)), respectively. In addition, blood loss in each group were 1461+/-389, 805+/-240 and 931+/-40 ml, respectively. CONCLUSION: Preanesthetic oral clonidine decreased the dose of PGEI required to produce hypotension, and decreased the blood loss during operation.

Administration, Oral↗

PubMed1999

The mechanism of focal intestinal perforations in neonates with low birth weight.

Among 36 neonates with intestinal perforations (IP) between 1975 and 1996, 5 had necrotizing enterocolitis (NEC IP) and 10 had focal IPs (FIP). A histologic review of the bowel near the perforations was made to see if there was any difference between cases of NEC IP and FIP. In 1 case of NEC IP, a defect in the musculature was found in addition to disappearance of the mucosal villi and dilated vessels or hemorrhage in the submucosa. Thinning or absence of the intestinal musculature and short villi in the mucosa was observed in 3 cases of FIP, but the acute ischemic changes in FIP were much less than in NEC IP. Hypothesizing that the defective musculature in FIP may be acquired by a vascular accident either before or after birth, we examined the histology of the latest consecutive infants diagnosed as having meconium peritonitis (MP) due to in-utero volvulus and perforation. In the tissue near the perforation, there was an identical focus of thinning and interruption of the musculature while the acute ischemic changes were minimal. We speculate that thinning or absence of the intestinal musculature in FIP may be a result of a transient ischemic event occurring in-utero and that FIP may develop in the damaged intestine after birth when it is fully dilated.

Female↗

PubMed1999

Treatment effects of bisphosphonates on ovariectomy-induced osteopenia in rats: comparison between clodronate and etidronate.

We studied the effects of clodronate and etidronate on bone loss induced by ovariectomy (OVX) in rats. Drug administration was initiated 8 weeks after the surgery and continued for 12 weeks (twice per week, s.c.). Lumbar (L4-L5) bone mineral density (BMD) and femoral BMD in the sham-operated group were increased to 113% and 114%, respectively, whereas those in OVX group were suppressed to 98.8% and 105%. Clodronate significantly restored the suppressed BMD over the entire dose range used (4-25 mg/kg). Etidronate restored BMD only at 4 mg/kg. In a histomorphometric analysis of lumbar vertebrae, both bisphosphonates depressed the amount of labeled surface, which was increased by OVX, to 11.9%-20.1% of the OVX group value for clodronate and to 0.23%-9.7% of the OVX group value for etidronate. The osteoid area was significantly increased by etidronate treatment over the entire dose range (OS/BS, 175%-295%). On the other hand, the osteoid area in the clodronate group did not increase at any dose tested (OS/BS, 38.1%-49.9%). Urinary excretion of deoxypyridinoline and plasma level of osteocalcin were elevated in the OVX group (162%-182% and 123%, respectively), suggesting that OVX enhanced bone turnover. Both bisphosphonates suppressed the bone turnover accelerated by OVX, and the data indicated that both bisphosphonates recovered BMD by means of inhibition of bone resorption. These data suggested that clodronate and etidronate reversed osteopenia induced by ovariectomy in rats. As judged from the dose response of BMD and histomorphometric findings, clodronate showed a wider safety margin than etidronate.

Amino Acids↗

PubMed1999

Effects of short-acting and long-acting loop diuretics on heart rate variability in patients with chronic compensated congestive heart failure.

BACKGROUND: We investigated the effects of a short-acting loop diuretic (furosemide) and a long-acting loop diuretic (azosemide) on heart rate variability, fluid balance, and neurohormonal responses in patients with mild to moderate chronic congestive heart failure. METHODS: Nineteen patients with mild to moderate chronic congestive heart failure received furosemide (40 to 60 mg/day) or azosemide (60 to 90 mg/day) for 5 days in a crossover manner. We performed time-domain and frequency-domain analyses of 24-hour Holter electrocardiographic recordings to assess heart rate variability. RESULTS: The 24-hour urinary sodium excretion was similar during the furosemide and azosemide treatment periods but was significantly greater in the first 2 hours after drug administration during furosemide treatment. Plasma renin activity and the hematocrit level increased and high-frequency power significantly decreased 2 hours after the administration of furosemide only. The standard deviation of all normal R-R intervals and the root mean square of successive differences in the R-R interval were lower with furosemide than with azosemide (P <.05). CONCLUSIONS: Furosemide, a short-acting loop diuretic, has a greater influence on heart rate variability and fluid balance than azosemide, a long-acting loop diuretic, in patients with mild to moderate chronic congestive heart failure.

Blood Pressure↗

PubMed1999

Time course of endothelin-1 and adrenomedullin after the Fontan procedure.

BACKGROUND: The endothelium-derived vasoconstrictor endothelin (ET)-1 might contribute to the physiology of blood flow regulation and play a role in cardiovascular disease. Adrenomedullin (AM) is a potent vasodilator peptide that has major effects on cardiovascular function and has multiple biologic effects involved in cardiovascular homeostasis. Although pulmonary vascular resistance is known to be one of the most important factors to determine the indications for a Fontan procedure, the time course of the plasma cytokine before and after the Fontan procedure is not known. METHODS: Sixteen patients were divided into two groups, 8 patients (1 to 14 years) who had the Fontan procedure (atriopulmonary connection) and 8 age-matched controls who had biventricular repair with normal central venous pressure. Plasma ET-1 and adrenomedullin levels were measured in both groups immediately before cardiopulmonary bypass, immediately after cardiopulmonary bypass, and 6 and 24 hours after cardiopulmonary bypass. A thermodilution catheter was inserted during the operation, and mean pulmonary arterial pressure, pulmonary wedge pressure, and cardiac output were measured, and pulmonary vascular resistance was calculated at the same time points. Correlation between the plasma ET-1 levels and pulmonary vascular resistance data were obtained in the Fontan group. RESULTS: Plasma ET-1 levels in the Fontan group were elevated after operation and were higher than the control group at 6 and 24 hours after cardiopulmonary bypass. Plasma adrenomedullin in the Fontan group was lower than in the control group at 6 and 24 hours after cardiopulmonary bypass. A significant positive correlation was obtained between the plasma ET-1 and pulmonary vascular resistance data (r = 0.475). CONCLUSIONS: Imbalance between increased ET-1 and relatively decreased adrenomedullin after cardiopulmonary bypass in the Fontan procedure could contribute to dominant effects of ET-1, which might induce vasoconstriction after the Fontan procedure. ET-1 might play an important role in maintaining vasoconstriction after the Fontan procedure.

Adolescent↗

PubMed1999

The long-term results of commissure plication annuloplasty for congenital mitral insufficiency.

BACKGROUND: Mitral valve repair in the pediatric population remains demanding because of a diversity of apparatus anomalies and the young age of the patients. METHODS: We reviewed our clinical results for mitral valve repairs for congenital mitral insufficiency. Forty-nine consecutive patients aged 2 months to 34 years (mean, 4.4 years) had mitral valve repair between June 1984 and December 1996. Forty-one patients (83.7%) had associated cardiac anomalies. The predominant pathologies for the regurgitations were chordal anomalies in 34 patients (69%), annular dilatation in 8 (16%), and leaflet anomalies in 7 (14%). Mitral valve repair included commissure plication annuloplasty in 43 patients (88%), modified DeVega in 11, cleft closure in 5, plication of the anterior leaflet in 3, triangular resection of the anterior leaflet in 2, chordal shortening in 1, and placement of artificial chordae in 1. Several combined techniques were required in 19 patients. RESULTS: There were no early or late deaths. The follow-up period was from 6 to 166 months (mean, 88.4 months). Forty-seven patients (95.9%) were in New York Heart Association class I. The long-term echocardiographic studies showed that 2 of 30 patients without reoperation had moderate regurgitation. The actuarial freedom from reoperation was 85.6% (95% confidence limits, 72.8%, 98.4%) at 13 years. Five patients (10.2%) required valve replacement from 13 days to 75 months after the valve repair. Two patients had cerebral ischemic events as a result of cardiomegaly and atrial fibrillation. CONCLUSIONS: Valve repair for congenital mitral insufficiency gave adequate results in combination with commissure plication annuloplasty and other techniques with excellent long-term functional status.

Adolescent↗

PubMed1999

Lipopolysaccharide-binding protein of Bombyx mori participates in a hemocyte-mediated defense reaction against gram-negative bacteria.

BmLBP is a lipopolysaccharide-binding protein in B. mori and participates in bacterial clearance in vivo. Here, we investigated the function of BmLBP more specifically. More than 90% of injected gram-negative rough strains to which BmLBP binds were removed from the plasma within 30 min post-injection, whereas it required 8h for the clearance of smooth strains to which BmLBP does not bind. Observation of the hemocoel after the injection of Escherichia coli rough strain showed that melanized nodules were formed at 30 min post-injection when the clearance of injected E. coli cells had occurred. Fluorescence microscope observation revealed that E. coli cells were actually trapped in the nodules formed in vivo. Furthermore, plasma pre-treated E. coli rough cells (BmLBP bound) added to hemocytes isolated in vitro caused vigorous hemocyte aggregations with the bacteria, while plasma pre-treated smooth cells did not. The formation of aggregates was inhibited by anti-BmLBP serum pre-treatment, suggesting that BmLBP causes the clearance of bacteria by promoting hemocyte nodule formation.

Journal Article↗

PubMed1999

Measurement of adsorption of salivary proteins onto soft denture lining materials.

STATEMENT OF PROBLEM: The adhesion of Candida albicans to soft liners is a major causative factor in denture stomatitis. It has been suggested that salivary proteins play an important role in this candidal adhesion. PURPOSE: This study measured the adsorption of salivary proteins on soft liners. MATERIAL AND METHODS: Five commercial materials and 1 experimental material were immersed in saliva, albumin solution, or milk. Proteins adsorbed on the material surfaces were measured by ATR/FT-IR spectroscopy. RESULTS: The amount of proteins adsorbed to the 6 materials varied considerably. Protein adsorption was significantly lower in the experimental fluoropolymer and polyphosphazene, and higher in acrylic resin and silicone. CONCLUSION: Different soft liners promote adsorption of varying amounts of protein.

Adsorption↗

PubMed1999

Altered sympathetic and vagal modulations of the cardiovascular system in patients with pheochromocytoma: their relations to orthostatic hypotension.

To examine sympathetic and vagal cardiovascular regulatory mechanisms in the pathogenesis of orthostatic hypotension in pheochromocytoma, we continuously monitored blood pressure (Finapres) and RR interval (electrocardiogram) in supine and standing positions in 12 patients with pheochromocytoma, 43 patients with essential hypertension, and 30 normotensive subjects. Mayer wave power spectrum of systolic blood pressure variability (approximately 0.1 Hz) and respiratory power spectrum of the RR interval variability (approximately 0.25 Hz) were taken as measures of sympathetic vascular and cardiac vagal modulations, respectively. Systolic blood pressure decreased more upon standing in pheochromocytoma patients (-21 +/- 7 mm Hg) than in normotensive subjects (-5 +/- 2 mm Hg) or essential hypertensive patients (-3 +/- 2 mm Hg) (P < .005 for both), whereas heart rate tended to increase most in the pheochromocytoma group. Postural reduction in systolic blood pressure was highly correlated with postural increase in heart rate (reciprocal change in RR interval) in the pheochromocytoma group (r = 0.716, P < .01) suggesting that baroreflex is well functioning in those patients. The Mayer wave power spectrum in recumbency was extremely depressed in pheochromocytoma patients (1.1 +/- 0.2 mm Hg2) compared with normotensives (4.5 +/- 0.8 mm Hg2) or essential hypertensives (5.6 +/- 0.6 mm Hg2) (P < .001 for both). This parameter increased significantly with standing in all groups but remained lower in patients with pheochromocytoma (5.1 +/- 1.0 mm Hg2) than in normotensives (7.1 +/- 0.9 mm Hg2, P = NS), whereas essential hypertensive patients demonstrated far greater value (19.2 +/- 3.8, P < .01 for both). The respiratory power spectrum of the RR interval in recumbency of pheochromocytoma patients (189 +/- 54 msec2) was less than in normotensive subjects (714 +/- 100 msec2, P < .001) but did not differ from that in patients with essential hypertension (214 +/- 41 msec2). The respiratory power spectrum of the RR interval upon standing was markedly suppressed in pheochromocytoma patients (36.9 +/- 16.7 msec2) compared with normotensive subjects (129.5 +/- 23.6 msec2) or essential hypertensive patients (126.6 +/- 28.6 msec2) (P < .001 for both). Postural decrement in the respiratory power spectrum of the RR interval correlated positively with postural increase in heart rate (r = 0.577, P < .05) in patients with pheochromocytoma. After successful surgery (n = 9), the Mayer wave power spectrum of the systolic blood pressure and the blood pressure response to orthostasis were normalized. These data suggest that altered sympathetic vascular regulation is central to the pathogenesis of orthostatic hypotension in pheochromocytoma, whereas cardiac vagal regulation acts to compensate.

Adrenal Gland Neoplasms↗

PubMed1999

Development of recombinant B subunit of Shiga-like toxin 1 as a probe to detect carbohydrate ligands in immunochemical and flowcytometric application.

Measurement of carbohydrate binding activity of Escherichia coli Shiga-like toxin in a simple and quantitative way is an important step for evaluation of antibodies with therapeutic value and of effectiveness of vaccine treatment. We constructed a plasmid vector (pVT1-B5) to express carbohydrate binding (B) subunit of Shiga-like toxin 1 without expression of toxic (A) subunit, and established a simple method to purify the recombinant B subunit, which was then labeled with digoxigenin. The binding specificity of the digoxigenin-labeled B subunit for globotriaosylceramide was established by thin-layer chromatography immunostaining. We developed an enzyme-linked immunosorbent assay using immobilized glycolipids, demonstrating high sensitivity and clear-cut specificity of the assay. The digoxigenin-labeled B subunit was also readily applicable to the detection of cell surface carbohydrate ligands by flow cytometry.

Carbohydrates↗

PubMed1999

Poorer nutritional status of the older-generation in a Japanese farming village, as related to fewer types of food consumed.

This study was carried out to determine whether the most recent nutritional improvements in Japanese farming villages were due to improvement in the diet of the young only or across all ages. Food duplicates for 24 h were collected. The number of food items and the adequacy of each nutrient level were compared between subgroups, by age of cooking and those eating meals. The older-generation used and ate fewer food items resulting in poorer nutrition. The most recent improvement in nutrition in the farming villages of Japan was found mainly to affect the younger-generation with the older-generations being more poorly nourished.

Adult↗

PubMed1999

Genomic origin and transcriptional regulation of two variants of cGMP-binding cGMP-specific phosphodiesterases.

We have reported alternative splice variants of cGMP-binding cGMP-specific phosphodiesterases (PDE5A), i.e. rat PDE5A2, human PDE5A1, canine PDE5A1 and PDE5A2, which possess distinct N-terminal sequences. In this study, the DNA sequences corresponding to the unique N-terminal portions of PDE5A1 and PDE5A2 were shown to be tandemly located upstream of exons encoding the common region of PDE5A in both human and rat PDE5A genes. The presence of human PDE5A2 and rat PDE5A1 transcripts in lung was confirmed by reverse transcriptase-PCR. These results indicated that two variant forms of PDE5A exist in humans, canines and rats. We examined the tissue distribution of the two variants of human PDE5A in adult and fetal humans. The patterns of expression of the two alternatively spliced transcripts of human PDE5A in human tissues differed. Many putative regulatory elements including cAMP response elements were observed in the 5'-untranslated region and intron of the PDE5A gene. The levels of the PDE5A transcripts, especially the PDE5A2 transcripts, were increased by a cAMP analogue in cultured rat vascular smooth muscle cells, indicating that the PDE5A2 is an inducible variant of PDE5A in rats.

3',5'-Cyclic-GMP Phosphodiesterases↗

PubMed1999

Fusion of intussusceptum and intussuscipiens in intrauterine intussusception: a rare type of intestinal atresia.

Intrauterine intussusception is well known as one of the rare causes of intestinal atresia. Although the polypoid intussusceptum is usually observed at the obstructed end on the distal side, a few cases with the polypoid lesion located apart from the blind end have been reported. To elucidate the etiology of separated polypoid intussusceptum, we reviewed 42 surgical cases of jejunal or ileal atresia over the last 12 years at Kobe Children's Hospital, Kobe, Japan. Of the 42 cases, 11 were intrauterine intussusception. Two of the 11 cases were associated with polypoid intussusceptums separated from the obstructed ends; the intestinal portion between the polypoid intussusceptum and the obstructed end showed a partial two-fold proper muscle wall and a mesenteric structure invaginated between the two walls. Another case showed linear ulcers facing each other on both the intussusceptum and intussuscipiens. Linear ulceration and subsequent fusion of the intussusceptum and intussuscipiens are suggested to be the pathogenesis of the first two cases.

Age of Onset↗

PubMed1999

Retrograde intra-arterial infusion of prostaglandin E1 and heparin for the no-reflow phenomenon after oromandibular reconstruction with a free fibular flap.

The authors encountered a patient with a tumor of the floor of the mouth in whom the no-reflow phenomenon occurred after excision of the lesion and the mandible, followed by reconstruction using a free fibular flap. A catheter was inserted retrogradely from the point where the peroneal artery had been ligated at the time of flap preparation. Continuous intra-arterial infusion of prostaglandin E1 and heparin was performed, and the flap survived. This method salvaged free flaps subject to the no-reflow phenomenon.

Alprostadil↗

PubMed1999

Characteristics of blood pressure measured at home in the morning and in the evening: the Ohasama study.

OBJECTIVE: To determine the qualitative and quantitative differences of blood pressure measured at home (home measurement) in the morning versus the evening. METHODS: Of 3744 participants, aged 20 years or older in the Ohasama population, more than 14 home measurements in the morning and in the evening, respectively, were obtained in each of 1207 individuals (881 untreated, 56.1 +/- 11.4 years and 326 treated, 66.0 +/- 9.2 years). A casual/screening measurement was also obtained in these individuals. RESULTS: The home measurements in the morning were significantly higher than those in the evening. The bivariate linear regression analysis demonstrated that the difference between diastolic home measurement in the morning and that in the evening increased with an increase in diastolic home measurements. The multiple step-wise linear regression analysis, however, demonstrated that male sex, the use of antihypertensive medication, and SD of home measurements in individuals (blood pressure variability), but not level of home measurements, were positively associated with the difference between home measurement in the morning and that in the evening. The SD of home measurement in the evening in individuals was significantly larger than that in the morning, and the SD in treated individuals was significantly larger than that in untreated individuals. The correlations between casual and home measurements were moderate in untreated individuals (r = 0.509-0.567) but poor in treated subjects (r= 0.223-0.384). The correlations between home systolic measurements in the morning and in the evening were very close in both treated and untreated subjects (r = 0.814-0.902). The correlations between the SD of home measurements in the morning and in the evening were moderate in both treated and untreated individuals (r = 0.585-0.657). CONCLUSIONS: Qualitative and quantitative differences in home blood pressure measurement, due to the differential time of measurement, should be taken into consideration in clinical use of home blood pressure measurements.

Adult↗