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Biomedical subjects

Y Imai

Publications and source records attributed to Y Imai.

At least 325 records · Page 18Linked to original sources
PubMed1998

Transfusion-associated graft-versus-host disease in immunocompetent patient: early diagnosis and therapy.

We report a case of transfusion-associated graft-versus-host disease in a previously healthy, 68-year-old Japanese man following an emergency surgery for an acute aortic dissection. We confirmed the chimerism of lymphocytes and the effect of drug therapy using DNA polymorphism analysis. This method is a sensitive, convenient, and rapid method that it is also useful for the evaluation of therapy. And the combination therapy with methylprednisolone, cyclosporine, and 15-deoxyspergualin may be effective in treating transfusion-associated GVHD.

Aged↗
PubMed1998

Radiofrequency pulmonary valvotomy using a new 2-French catheter.

We report the usefulness of a new 2-French (F) electrode catheter for perforating the atretic pulmonary valve in patients with pulmonary atresia and intact ventricular septum, using radiofrequency energy. The new 2-F electrode catheter was used in three patients. The first patient, weighing 2.1 kg, with pulmonary atresia and an intact ventricular septum, underwent transcatheter valvotomy at the age of 18 days. Due to massive left ventricular volume overload, the patient required surgical ligation of the ductus arteriosus, but she was discharged uneventfully after that. The second patient, weighing 2.2 kg, had Ebstein's anomaly with pulmonary atresia and an intact ventricular septum. She underwent transcatheter valvotomy at the age of 30 days. Although she was weaned from prostaglandin E1 infusion, she died suddenly (presumed septicemic). A postmortem examination showed a split pulmonary valve. The third patient, weighing 2.3 kg, with pulmonary atresia and an intact ventricular septum, underwent transcatheter valvotomy at the age of 17 days. Prostaglandin E1 infusion was discontinued on the 3rd day after the transcatheter valvotomy and she was discharged uneventfully.

Angiography↗
PubMed1998

[Surgical management of patent ductus arteriosus in low body weight infants].

Between January 1980 and December 1994, seventeen premature infants weighing less than 2500 g underwent surgical management for the isolated patent ductus arteriosus (PDA). Indometacine therapy for closure of PDA was not effective for all these patients. In terms of the body weight at birth, they were divided into two groups; Group I (G-I) consisted of ten patients with birth weight less than 1000 g and Group II (G-II) of seven patients weighing more than 1000 g. The age at operation was 22.1 +/- 15.4 days in the G-I and 14.3 +/- 11.4 days in the G-II. The ductus was ligated in all patients but one of the G-II, in whom it was divided. There were five (50%) hospital deaths in the G-I and none in the G-II. The causes of death in the G-I were related to necrotizing enterocolitis (NEC) in two and infant respiratory distress syndrome (IRDS), acute renal failure, and broncho-esophagial fistula in each. The age at operation tended to be older in nonsurvivors rather than in survivors in the G-I (28.0 +/- 16.8 days vs. 16.2 +/- 14.0 days, respectively, but the difference did not reach significance). Before surgery, all patients in the G-I required mechanical ventilator support and nine of them were associated with IRDS. In contrast, only two patients in the G-II needed mechanical ventilation preoperatively. The postoperative period of intubation was also significantly longer in the G-I than in the G-II (51.6 +/- 35.2 days vs. 2.2 +/- 1.5 days, respectively, p < 0.05). In conclusions, the surgery for PDA can be safely performed even in small premature babies weighing less than 1000 g. When medical therapy for PDA is not effective in the premature patients, the surgical management should be considered as early as possible before their conditions become worse due to such critical complications as NEC, IRDS, and renal failure.

Cardiac Surgical Procedures↗
PubMed1998

Differential expression of SHP2, a protein-tyrosine phosphatase with SRC homology-2 domains, in various types of renal tumour.

SHP2, a widely distributed protein-tyrosine phosphatase with src homology-2 (SH2) domains, is highly expressed in the brain and may play a role in synaptic communications or cellular proliferation. In this study, we examined SHP2 protein expression in 110 renal cell tumours of various histological subtypes, including clear, granular, papillary, chromophobe, collecting duct, and sarcomatoid-type renal cell carcinoma (RCC), and oncocytoma. SHP2 was expressed predominantly in normal distal tubules and collecting ducts, and positivity in various types of renal tumours was as follows: clear cell RCC, 0% (0/77 cases); granular, 7.7% (1/13); papillary, 50% (3/6); sarcomatoid, 0% (0/1); chromophobe, 85.7% (6/7); collecting duct carcinoma, 0% (0/2); oncocytoma, 100% (4/4). Clear and granular-type RCCs showed a very low but positive expression of SHP2. Chromophobe RCC and oncocytoma showed the highest rates and strongest intensities of SHP2 protein on immunostaining. SHP2 may serve as a powerful marker in detecting rare tumours. Estimates of its expression may be useful in histological diagnosis.

Adenoma, Oxyphilic↗
PubMed1998

Expression of type IV collagen in the developing human kidney.

The distribution of alpha1-6 chains of type IV collagen (alpha1-6(IV)) in human fetal kidneys was examined by indirect immunofluorescence. By 11 weeks of gestation, alpha1, 2, 3, 4, and 6(IV) were already present, but alpha5(IV) appeared relatively late, at 21 weeks. Alpha1(IV) and alpha2(IV) were present in all basement membranes, alpha3(IV) and alpha4(IV) were restricted to the glomerular basement membrane and parts of the tubular basement membrane. Alpha5(IV) was distributed in the glomerular basement membrane, Bowman's capsule, and parts of the tubular basement membrane. Alpha6(IV) was present in the Bowman's capsule, parts of the tubular basement membrane, and occurred in parts of the glomerular basement membrane at the early capillary loop stage, but disappeared during the later capillary loop stage.

Amino Acid Sequence↗
PubMed1998

Primary cancer of the small intestine and mutational analysis of the K-ras and p53 genes.

A 69-year-old woman was admitted to Hokuso Shiroi Hospital because of recurrent pain in the lower right side of the abdomen. Small-intestinal cancer was strongly suspected after fluoroscopy of the small intestine. Laparotomy showed advanced cancer of the ileum, of complete annular constrictive type, 9.5 x 5cm in size. Histologically it was moderately differentiated tubular adenocarcinoma. Neither visceral nor nodal metastases were found, and the patient has been well for the 20 months since surgery. The strong resemblance between the epidemiological characteristics of small-intestinal cancers and colorectal cancers prompted us to investigate the carcinogenetic mechanisms at the molecular level. A point mutation at codon 12 of the K-ras gene was found, while no alterations were noted in the p53 gene, whose mutations are frequent in colon cancers. The carcinogenetic mechanisms of the small-intestinal cancer we experienced may thus differ from those of colon cancers.

Adenocarcinoma↗
PubMed1998

Malignant insulinoma presenting a non-functioning metastatic liver tumor 14 years after resection of the primary tumor.

A 58-year-old woman who had undergone resection of insulinoma 14 year earlier visited our clinic complaining of abdominal discomfort. Computerized tomographic scan showed multiple liver tumors, and a diagnosis of metastatic tumor of malignant islet cell tumor was confirmed histologically. No oversecretion of hormones or hypoglycemic episode was observed on readmission. Thus, the insulinoma seemed to have transformed to a clinically non-functioning tumor. The patient was treated with transcatheter arterial embolization, resulting in clinical improvement with marked reduction in tumor size. Features of interest in this case included; (1) transformation to non-functioning metastatic liver tumor 14 years after resection of insulinoma, (2) the usefulness of transcatheter arterial embolization for multiple metastatic tumor of malignant islet cell tumor.

Angiography↗
PubMed1998

Hemodynamic effects of human atrial natriuretic peptide after modified Fontan procedure.

BACKGROUND: Reduction of pulmonary vascular resistance and maintenance of urine output are important after the modified Fontan procedure. Atrial natriuretic peptide (ANP) has the effects of a vasodilator (including the pulmonary arteries) and a physiologic diuretic, and newly synthesized human ANP is available. We measured plasma ANP levels before and after the Fontan procedure and examined the effects of human ANP on hemodynamic parameters after the Fontan procedure. METHODS: Eight patients, aged 2 to 15 years, underwent the Fontan procedure (atriopulmonary connection). Blood samples were taken before and 3 hours after operation, and plasma ANP levels were measured by radioimmunoassay. The correlation between central venous pressure and ANP was examined. Human ANP was infused intravenously at a dosage of 0.1 microg x kg(-1) x min(-1) for 1 hour after the Fontan procedure under controlled ventilation and another blood sample was obtained. Urine volume and central venous pressure were measured, and pulmonary vascular resistance and the cardiac index were calculated by the thermodilution catheter method before and after human ANP infusion. One hour after human ANP infusion was discontinued, the evaluation was repeated. No other diuretics were given and the infusion rates of catecholamine were kept constant during these measurements. RESULTS: Plasma ANP levels before and after the Fontan procedure were 29.1 and 54.9 pg/mL, respectively, and a positive correlation was obtained between central venous pressure and plasma ANP levels (r = 0.661, p < 0.05). Human ANP infusion significantly decreased central venous pressure and pulmonary vascular resistance, and increased urine volume and the cardiac index, whereas the plasma ANP level was elevated to 617.5 pg/mL. Systemic blood pressure did not change significantly. CONCLUSIONS: Atrial natriuretic peptide is secreted in response to elevated central venous pressure after the Fontan procedure, but its concentration might not be sufficient. Human ANP can be a therapeutic choice after the Fontan procedure as a physiologic diuretic and a pulmonary vasodilator.

Adolescent↗
PubMed1998

Atrial septal displacement for repair of anomalous pulmonary venous return into the right atrium.

BACKGROUND: In the repair of anomalous connection of the pulmonary veins to the right atrium, the use of a baffle of pericardium to divert the pulmonary venous blood into the left atrium could cause pulmonary venous obstruction as a result of thickening of the pericardial patch. Anomalous pulmonary venous drainage to the right atrium caused by malposition of the atrial septum primum can be repaired by displacing the shifted septum primum to the normal position. METHODS: In 5 patients with total (n=2) or partial (n=3) anomalous pulmonary venous drainage into the right atrium, the septum primum was shifted toward the left atrium and the pulmonary veins drained into the anatomic right atrium despite their normal connection with the posterior wall of the left atrium. This method consisted of incision of the posterior edge of the atrial septum primum and displacement of the incised atrial septum between the anomalous pulmonary veins and both venae cavae. No patch was used. RESULTS: Postoperative echocardiography showed a wide pathway from the pulmonary veins to the left atrium with no stenotic portions. No atrial arrhythmias occurred after the operation. CONCLUSIONS: This technique may be advantageous because it allows for future growth of the route of the pulmonary venous pathway and avoids postoperative supraventricular arrhythmias.

Arrhythmias, Cardiac↗
PubMed1998

Marginal irregularity of flat elevated type of colorectal tumor as a marker of malignant potential.

BACKGROUND: The malignant potential of superficial elevated type tumors is still controversial. Because biopsy specimens alone are sometimes not sufficient for diagnosis due to histologic heterogeneity within the tumor, other clinical parameters for evaluation of the degree of malignancy would be helpful. METHODS: A new morphometric parameter, the "F-circle," which represents the irregularity of the tumor margin, was studied in 115 endoscopically recognized superficial, flat, elevated type colorectal tumors without a central depressed area with respect to histologic evaluation of the degree of malignancy. RESULTS: The mean F-circle values of adenomatous lesions with mild or moderate atypia, severe atypia, and adenocarcinoma were 0.709+/-0.115, 0.619+/-0.149, and 0.536+/-0.133, respectively. CONCLUSION: The superficial elevated type of colorectal tumor having more marginal irregularity had a greater malignant potential, and the F-circle may be a useful clinical parameter for evaluation of the degree of malignancy.

Adenocarcinoma↗
PubMed1998

Inhibition of Na+,K(+)-ATPase by platelet-activating factor in dog submandibular glands.

Physiological stimulation of dog submandibular gland has been shown to generate platelet-activating factor (PAF). However, PAF is not released from cells in the tissue. To assess its intracellular activity, the effect of PAF on Na+,K(+)-ATPase was examined in dog submandibular gland cells. PAF inhibited Na+,K(+)-ATPase in membrane preparations, and the inhibitory effect was dependent on the protein concentration in the enzyme preparation. The inhibitory effect of a low concentration of PAF was antagonized by a PAF-receptor antagonist, BN 50,739, but at high concentrations, PAF was not antagonized. Kinetic analysis of PAF inhibition of Na+,K(+)-ATPase suggests that the inhibition of Na+,K(+)-ATPase by PAF is not due to competition by PAF at K(+)- or Na(+)-binding sites on the enzyme, but by complex inhibitory mechanisms. These results suggest that PAF may interact with specific and nonspecific site of action resulting in the inhibition of Na+,K(+)-ATPase. Ouabain increased mucin release from dog submandibular gland cells. Because Na+,K(+)-ATPase and ion exchange pathways are important in the secretory responses of acinar cells, PAF may regulate intracellularly the secretory function of acinar cells by modulating Na+,K(+)-ATPase and ionic homeostasis.

Animals↗
PubMed1998

Cloning of a gene, YT521, for a novel RNA splicing-related protein induced by hypoxia/reoxygenation.

To elucidate the role of astrocytes in the stress response of the central nervous system to ischemia, early gene expression was examined in rat cultured astrocytes after the exposure to hypoxia/reoxygenation, and we have previously cloned a novel RNA binding protein, RA301, from the reoxygenated astrocytes. Furthermore, we have now cloned a new gene for RA301 binding protein, termed YT521, by a yeast two-hybrid screening technique to explore RA301 functions. The YT521 cDNA is about 3200 bp long with an open reading frame encoding 712 amino acids. This amino acid sequence contains arginine-aspartic acid-glutamic acid rich region and glutamic acid rich one, and has a low degree of homology with RNA binding proteins such as U1-70k. Northern blot analysis revealed that YT521 mRNA expression was up-regulated in reoxygenated astrocytes. Induction of YT521 mRNA was mediated by endogenously generated reactive oxygen species, as it was suppressed by treatment of the cells with diphenyl iodonium which blocks oxygen-free radical formation by astrocytes. These expression patterns resembled those of RA301 mRNA. Far Western blot analysis showed that YT521 protein was not only interacting with RA301 protein, but also with SC35 and SF2, both of which are splicing factors. These results suggest that YT521 is a novel candidate for RNA splicing-related protein.

Amino Acid Sequence↗
PubMed1998

Decreased blood pressure variability at rest in patients with primary aldosteronism.

Increased blood pressure (BP) variability in essential hypertension (EH) is attributed in part to a reduction in baroreflex sensitivity. We previously showed that baroreflex sensitivity is not reduced in hypertension associated with primary aldosteronism (PA) compared with normotensive (NT) subjects. This study examined whether the preservation of baroreflex function in patients with PA would prevent an increase in BP variability. The beat-to-beat BP (measured with Finapres) and RR interval (from electrocardiograms) were monitored for 10 min in the supine and standing positions in 34 patients with PA, 60 patients with EH, and 45 NT subjects. Recordings were also performed during mild ergometer exercise in 7 PA patients, 8 EH patients, and 9 NT subjects. Blood pressure variability was assessed by both standard deviation (SD) and coefficient of variation (CV). Baroreflex sensitivity (BRS) was assessed by the closed-loop gain between systolic BP and RR interval variability. The SD and the CV of systolic BP (SBP) and the CV of diastolic (DBP) BP were significantly smaller in patients with PA than in patients with EH in both supine and standing positions. The SD of SBP and DBP were similar in patients with PA and NT subjects, although the CV were significantly smaller in patients with PA. The BRS was inversely correlated with both the SD and CV for SBP in the supine (r = -0.397 and -0.440, P < .05, respectively) and standing (r = -0.457 and -0.412, P < .05, respectively) positions in patients with PA. Exercise reduced the BRS in all groups (70%, 26%, and 64% for PA, EH, and NT, respectively, P < .01). Blood pressure variability did not change significantly during exercise, compared with rest, in the PA and NT groups but was decreased (P < .05) in the patients with EH. In conclusion, primary aldosteronism is characterized by decreased supine and standing BP variability, which is due in part to the preservation of baroreflex function. Our data further showed that BP variability is minimized by nonbaroreflex mechanisms during mild exercise.

Adult↗
PubMed1998

The effects of preanesthetic oral clonidine on total requirement of propofol for general anesthesia.

STUDY OBJECTIVE: To investigate the effects of preanesthetic oral clonidine on total propofol requirement for uniform minor surgery (breast conservative surgery: breast cancer removal with axillary lymph node dissection), and to compare the action of clonidine with that of preanesthetic oral diazepam, a commonly used benzodiazepine. DESIGN: Randomized double-blinded study. SETTING: Operating room ASA physical status I and II room and recovery room of the cancer center. PATIENTS: 80 breast cancer patients scheduled for surgery. INTERVENTIONS: Patients were randomized to one of four treatment groups (placebo, clonidine 75 micrograms, or 150 micrograms of clonidine, or 10 mg of diazepam were orally administered 60 min before induction of anesthesia); n = 20 per group. After evaluating the sedation and anxiety levels of patients using a visual analog scale, anesthesia was induced with propofol (1.5 mg/kg), and maintained with oxygen (O2): nitrous oxide (N2O) (30:70) with a continuous infusion of propofol. The propofol infusion was started at 10 mg/kg/h for 10 minutes, then decreased to 8 mg/kg/h, and 6 mg/kg/h thereafter, and the rate of infusion was adjusted to obtain adequate anesthesia (maintaining hemodynamic parameters within 20% of that prior to premedication). Fentanyl 0.2 mg (each 0.1 mg was given for intubation and axillary lymph node dissection, respectively) was administered. MEASUREMENTS AND MAIN RESULTS: Preanesthetic oral clonidine (150 micrograms) and diazepam (10 mg) induced anxiolysis without sedation. The total requirement (the mean infusion rates) of propofol in placebo, clonidine 75 micrograms, clonidine 150 micrograms, and 10 mg of diazepam groups were 841 +/- 70 (9.0 +/- 0.3), 720 +/- 63 (7.1 +/- 0.4), 491 +/- 39 (5.6 +/- 0.2), and 829 +/- 77 mg (7.9 +/- 0.4 mg/kg/h), respectively. The cost of propofol in these groups was $51.0 +/- 3.8, $45.5 +/- 3.2, $33.5 +/- 2.3, and $50.5 +/- 4.4, respectively. CONCLUSIONS: Preanesthetic oral clonidine (150 micrograms) but not diazepam (10 mg) reduced the total requirement of propofol while stabilizing hemodynamic parameters. In addition, 150 micrograms of oral clonidine attenuates the hemodynamic responses associated with tracheal intubation.

Administration, Oral↗
PubMed1998

Calcaneus as a site for the assessment of bone mass.

The calcaneus is a skeletal site frequently used for monitoring bone loss after spaceflight, because it is sensitive to microgravity-induced bone mineral loss and reflects the degree of demineralization in the vertebra and the femoral neck. In this article, methods for assessing the calcaneus are reviewed, and their potential applications and limitations as the monitoring site for bone loss in weightlessness are discussed. Currently, single or dual energy X-ray absorptiometry appears to be most sensitive for monitoring bone mineral loss in weightlessness. The results of recent studies suggest two- to threefold longer follow-up times required for ultrasound techniques. However, ultrasound devices can be designed to be portable, making them attractive for inflight use, and ultrasound techniques are expected to provide information related to bone quality. Additional investigations that assess new ultrasound techniques would be important to determine and utilize the full potential of this technology for monitoring bone loss in weightlessness.

Absorptiometry, Photon↗
PubMed1998

Immunohistochemical study on a macrophage calcium-type lectin in mouse embryos: transient expression in chondroblasts during endochondral ossification.

We investigated expression of mouse macrophage galactose/N-acetylgalactosamine-specific calcium-type lectin (MMGL) in mouse embryos using a rat monoclonal antibody (mAb) LOM-14 that we previously developed. Immunoblot analysis revealed that a significant expression of MMGL was first detected in detergent extracts of whole embryos of 11 days post coitus (dpc) and the level of its expression increased during further fetal development (examined up to 18-dpc embryos). Tissue sections of 12, 14, 16, and 18-dpc embryos, newborn and adult mice were investigated by immunohistochemical staining. In embryos of 12-dpc and later stages, mesenchymal cells (typically distributed in the embryonic skin) exhibited positive signals for MMGL. Interestingly, a conspicuous staining was observed during endochondral ossification in temporary cartilage tissue, in which chondroblasts were transiently positive for MMGL. The staining intensity for the chondroblasts peaked in 14-dpc embryos and then gradually decreased. The staining was diminished while hypertrophy and maturation of chondrocytes proceeded, and was eliminated in areas with calcification. Immunoelectron microscopic study demonstrated the presence of MMGL in rough endoplasmic reticulum in the chondroblasts in the temporary cartilage tissue in 14-dpc embryos. These results provide first evidence showing the expression of MMGL in cells other than macrophages.

Animals↗
PubMed1998

Differential effects of antihypertensive drugs with differing pharmacological properties on the basal ambulatory blood pressure. Japanese Ambulatory Pressure-ANtihypertensive Effects SEarching study group.

To investigate how antihypertensive drugs with different pharmacological properties affect ambulatory blood pressure (BP) the JAPANESE Study Group developed a database of clinic and ambulatory BPs before and after antihypertensive treatment of patients throughout Japan. Drugs evaluated were nilvadipine (n = 195; b.i.d, 4-8 mg/day), amlodipine (n = 75; q.d., 2.5-10 mg/day), lisinopril (n = 80; q.d., 10-20 mg/day) and bisoprolol (n = 49; q.d., 5-10 mg/day). The relationship between basal ambulatory BP and the hypotensive effect on ambulatory BP during treatment was examined. All antihypertensive drugs significantly decreased both clinic BP and ambulatory BP. The hypotensive effect determined by measurement of clinic BP was significantly greater than that determined by ambulatory BP. The hypotensive effect was positively correlated with basal ambulatory BP. However, there was a quantitative difference in this characteristic among the drugs. The critical daytime systolic ambulatory BP below which a hypotensive effect was not observed was extrapolated to 128, 127 and 124 mm Hg with nilvadipine, amlodipine and bisoprolol, respectively, while that with lisinopril was 97 mm Hg. The slope of the correlation coefficient between basal daytime ambulatory systolic BP and hypotensive effect with lisinopril was significantly smaller than those with the other drugs (P < 0.0001). The slope for the relationship between night-time ambulatory systolic BP and the hypotensive effect with bisoprolol was the steepest (P < 0.0001). Antihypertensive drugs with different pharmacological properties exhibited differing hypotensive effects on the basal ambulatory BP. Such differences in efficacy of the drugs on the basal ambulatory BP may reflect adverse effects of the drugs and the prognosis of hypertension.

Adult↗