Biomedical subjects

Y Imai

Publications and source records attributed to Y Imai.

At least 883 records · Page 49Linked to original sources

PubMed1990

The measurement of internal pressure of ampoules and its application to commercial products.

This paper reports a method for determining the internal pressures of ampoules, from the head space and the change in volume on opening, as measured by displacement of water. Using this method, internal pressures of commercial ampoules were shown to be lower than atmospheric pressure. For example, the ratio of internal pressure to atmospheric pressure in a commercial ampoule of 5 mL distilled water was 0.884 at room temperature (23 degrees C).

Atmospheric Pressure↗

PubMed1990

Oxygen consumption for K+ uptake during post-stimulatory activation of Na+, K(+)-ATPase in perfused rat mandibular gland.

1. In order to determine the stoichiometry of K+ uptake and ATP consumption by Na+, K(+)-ATPase in the isolated, perfused mandibular gland of the rat, oxygen consumption and net K+ uptake from the vascular side were measured during the recovery period following K+ depletion by stimulation with acetylcholine in combination with ouabain. 2. Acetylcholine (10(-6) M) induced fluid secretion and an initial, transient release of K+ from the gland. Addition of ouabain suppressed salivary fluid secretion and caused an additional, dose-dependent, transient release of K+. 3. With acetylcholine (10(-6) M), the oxygen consumption of the gland increased to 62.4 +/- 4.2 microliters/(g min) from a resting value of 12.9 +/- 1.2 microliters/(g min). The increased oxygen consumption was suppressed by ouabain, in a dose-dependent fashion. 4. Withdrawal of acetylcholine and ouabain induced a net uptake of K+ and, simultaneously, an increase in oxygen consumption. The cumulative K+ uptake and the increment of oxygen consumption during the recovery period were dependent on the concentration of used ouabain. 5. The rates of K+ uptake and ATP hydrolysis were compared during recovery, assuming that six moles of ATP were hydrolysed for each mole of oxygen consumed. The data obtained during the later phase of the recovery lay on a single straight line with a slope of 1.8 for each of the various concentrations of ouabain, suggesting that the relationship between K+ uptake and energy consumption was linear. 6. Assuming the K+:ATP stoichiometry of the Na+, K(+)-ATPase to be 2:1, K+ would appear to be transported with ca 90% efficiency by Na+, K(+)-ATPase in the rat mandibular gland. Using 1.8-2.0 as a K+/ATP stoichiometry, the rate of primary active K+ uptake and the corresponding passive K+ efflux during secretion were estimated to be 20-22 mumol/(g min) from the oxygen consumption and the net K+ flux. 7. The passive K+ efflux was estimated, from the initial rate of K+ release caused by addition of 10(-3) M-ouabain, to be 30 mumol/g min). The discrepancy between the estimated active K+ uptake and passive K+ release (8-10 mumol/(g min] could be attributed to a secondary active K+ uptake process such as Na(+)-K(+)-2Cl-symport.

Acetylcholine↗

PubMed1990

Colorectal tumors: an in vitro study of high-resolution MR imaging.

To study the potential utility of magnetic resonance (MR) imaging in staging colorectal tumors, 15 resected colonic segments containing 17 elevated lesions were examined on a 1.5- or 1.9-T superconductive MR system. The whole intestinal wall was apparent as three or five layers on images obtained with a short repetition time (TR) and short echo time (TE) and as six or eight distinct layers, including the intestinal wall proper as well as an adherent mucus layer and an outer layer of pericolonic fat, on the long TR/TE images. In cases of colonic carcinoma, MR images correlated well with the pathologic findings, including the macroscopic growth pattern, depth of mural invasion, and the presence of foci of calcific tumor necrosis and pools of extracellular mucin (colloid). These features suggest that MR imaging may be valuable in the clinical evaluation of colorectal tumors.

Adenocarcinoma↗

PubMed1990

Decrease in rat submandibular acinar cell volume during ACh stimulation.

Changes in acinar cell volume were measured in the perfused submandibular gland of the rat at 23 degrees C during salivary secretion induced by acetylcholine (ACh). Cellular volume was monitored by two methods: the impedance method and the morphometric method using video-enhanced contrast optical microscopy. Both measurements revealed a decrease in acinar cell volume in response to 1 microM ACh. Within the 1st min of stimulation, secretion increased to the initial maximum (initial secretion), and cell shrinkage occurred. During sustained stimulation, secretory rate and cell volume were maintained at the plateau level (steady secretion). The decrease in cell volume was 71.8 +/- 2.9% of resting volume (means +/- SE, n = 8) as measured by the impedance method and 76.1 +/- 2.0% (n = 20) as measured by the morphometric method. With the removal of ACh, cell volume increased to 111.6 +/- 2.7% (n = 8) of the prestimulation level as measured by the impedance method and 108.8 +/- 1.5% (n = 20) as measured by the morphometric method, and then recovered to the prestimulation level slowly. The weight of the gland decreased significantly during stimulation. These findings proved that volume decrease occurred during stimulation. The measurement of cell volume gave the net fluid flux of the acinar cell compartment. The net fluid flux and the rate of salivary secretion gave an estimation of the fluid influx across the basolateral membrane. These findings suggest that a transcellular route for fluid secretion exists in the salivary gland.

Acetylcholine↗

PubMed1990

Effect of platelet-derived growth factor on the proliferation of blast progenitors from acute myeloblastic leukemia patients.

The effect of platelet-derived growth factor (PDGF) on self-renewal and terminal divisions of blast progenitors of acute myeloblastic leukemia was studied. The terminal divisions of blast progenitors were determined as the primary blast colony formation in methylcellulose culture; self-renewal was assessed by secondary colony formation by replating in methylcellulose and the recovery of clonogenic cells in suspension culture. PDGF neither enhanced nor suppressed primary or secondary blast colony formation in methylcellulose culture nor recovery of clonogenic cells in suspension. The results show that PDGF does not affect the self-renewal or terminal divisions of leukemic blast progenitors.

Adolescent↗

PubMed1990

Ventricular volume characteristics in double-inlet left ventricle before and after septation.

Septation is one of the surgical choices for double-inlet left ventricle, yet postoperative hemodynamics have not been well defined. We studied ventricular volume characteristics in 10 patients with double-inlet left ventricle before and after septation. Preoperative end-diastolic volume (EDV) of the ventricle was 291 +/- 111% (+/- SD) of normal and ejection fraction (EF) was 0.59 +/- 0.07. Postoperatively, EDV of the right-sided ventricle (RV) was 82 +/- 24%, and EDV of the left-sided ventricle (LV) was 153 +/- 41%. Ejection fraction of the RV was 0.77 +/- 0.10, and LVEF was 0.49 +/- 0.13. On the short-axis view of two-dimensional echocardiography, fractional change of the cross-sectional area was 0.65 +/- 0.16 for the RV and 0.23 +/- 0.11 for the LV. Fractional shortening of the septum-to-ventricular free wall axis was 0.51 +/- 0.17 in the RV and -0.05 +/- 0.09 in the LV. Analysis of the curvature of the new septum during cardiac cycle on two-dimensional echocardiography revealed that the septum shifted to the right side during systole in all patients in whom the systolic LV/RV pressure ratio was larger than 1.0. The septum shifted toward the LV during diastole in eight patients in whom end-diastolic pressure in the RV was higher than or equal to that in the LV, whereas it remained in the right side in two patients with higher left-side pressure. The cardiac index of these two patients was 2.4 and 2.6 l/min/m2, respectively, whereas it averaged 4.4 +/- 1.0 l/min/m2 in the other eight patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1990

Cardiovascular depression and stabilization by central vasopressin in rats.

The role of endogenous vasopressin in cardiovascular homeostasis was examined using vasopressin-deficient rats (Brattleboro) (n = 194) and their parent strain, Long-Evans rats (n = 181). Mean arterial pressure (blood pressure) and heart rate were measured every 4 seconds with or without infusion of drug solution for 21 hours, and mean values and their standard deviations (lability) were calculated. Blood pressure in Brattleboro rats (116 +/- 1.1 mm Hg, mean +/- SEM) was significantly higher than that in Long-Evans rats (96 +/- 0.7 mm Hg, p less than 0.001), whereas heart rates (381 +/- 3.3 and 375 +/- 2.9 beats/min, respectively) were similar. The lability of blood pressure and heart rate in Brattleboro rats (9.2 +/- 0.1 mm Hg and 42.3 +/- 0.7 beats/min) was also greater than that in Long-Evans rats (6.7 +/- 0.1 mm Hg, p less than 0.001 and 38.4 +/- 0.8 beats/min, p less than 0.01, respectively). In Brattleboro rats, intravenous vasopressin (0.1 ng/kg/min or 0.6 ng/kg/min) did not affect blood pressure, although it did reduce heart rate and decreased lability of blood pressure and heart rate. Intracerebroventricular (central) infusion of vasopressin (2 pg/kg/min) in Brattleboro rats induced initial hypertension and tachycardia followed by long-lasting hypotension and bradycardia, whereas in Long-Evans rats it induced only hypertension and tachycardia. In both strains, central vasopressin dramatically decreased the lability of blood pressure and heart rate. Neither intravenous (0.2 ng/kg/min) nor central desmopressin (2 pg/kg/min or 0.2 ng/kg/min), a V2 renal receptor agonist, changed any of these parameters in Brattleboro rats, although both diminished urinary volume. Neither intravenous (50 ng/kg/min) nor central (3.3 pg/kg/min) d(CH2)5-Tyr(Me)-arginine vasopressin, a vasopressin V1 receptor antagonist, modulated any of these parameters in Long-Evans rats. These results suggest that endogenous as well as exogenous vasopressin acts centrally as a cardiovascular inhibitor and stabilizer through a receptor mechanism other than V1 or V2 receptor mechanisms.

Animals↗

PubMed1990

Suppression of tumor cell growth and mitogen response by aporphine alkaloids, dicentrine, glaucine, corydine, and apomorphine.

The aporphine alkaloids, dicentrine, glaucine, corydine, and apomorphine were shown to have inhibitory activity against several mouse tumor cell lines, leukemia P388 and L1210, melanoma B16, bladder cancer MBC2, and colon cancer Colon 26 in culture. These aporphine alkaloids also inhibited the mitogen-induced lymphocyte proliferation as well as the growth of IL-2 dependent CTLL2 line in a dose-dependent way. Of the four alkaloids apomorphine proved to be most potent in the inhibitory action. Apomorphine treatment resulted in some prolongation of survival time of the mice inoculated i.p. with P388, although its activity was not enough to meet the standard criterion for antitumor activity.

Adenocarcinoma↗

PubMed1990

Inhibitory effect of bisbenzylisoquinoline alkaloids on the quick death of mice treated with BCG/LPS.

Three bisbenzylisoqinoline alkaloids, chondocurine (Chon), berbamine (Ber), and cycleanine (Cyc) were tested for their protective effect on the quick death of mice primed with bacillus Calmette Guerin (BCG) and elicited with lipopolysaccharide (LPS). Seven-consecutive treatments with Chon or Cyc at a dose of 10 mg/kg following BCG priming resulted in significant improvement in the survival rate. A single dose of Chon also protected the BCG/LPS-treated mice from death if it was given immediately after, not 4 h after, LPS elicitation. These data show that bisbenzylisoquinoline alkaloids can protect mice from the lethal toxicity induced by the BCG/LPS combination treatment by inhibiting the priming with BCG or the elicitation with LPS.

Alkaloids↗

PubMed1990

Serum hyaluronan concentration determined by radiometric assay in patients with pretibial myxedema and Graves' ophthalmopathy.

The serum concentration of hyaluronan (HA) was measured by radiometric assay in patients with pretibial myxedema (PTM) and Graves' ophthalmopathy (GO). The mean HA concentration in the patients (n = 8) was 21.2 +/- 15.3 (mean +/- SD) microgram/l, while that of Graves' disease without skin or eye involvement (n = 7) was 23.5 +/- 11.0 (mean +/- SD) microgram/l and that of the control (n = 8) was 25.5 +/- 16.4 (mean +/- SD) microgram/l. We conclude that local accumulation of glycosaminoglycan in PTM or GO is not associated with an increase in the serum HA concentration.

Adult↗

PubMed1990

[Mental health in software engineers. I. Frequency of mental complaints, physical complaints and psychiatric disorders].

This study examined the physical complaints, mental complaints and psychiatric disorders in software engineers. Subjects were 101 male software engineers. They were evaluated by a semistructured interview. Psychiatric diagnosis was based on DSM-III (Diagnostic and Statistical Manual of Mental Disorders, third edition). The results are summarized as follows: 1) Physical complaints were observed in 68% of the subjects with 25% of the subjects complaining of physical ill-health. This study showed that 12% of the subjects had hypertension, 12%, gastritis or gastro-duodenal ulcer, 14%, allergic disease, and 19% miscellaneous diseases. 2) Of the subjects 62% had mental complaints and 31% mental ill-health. Depressive symptom was the most frequent mental complaint with 32% of the subjects diagnosed as DSM-III. The common diagnoses were adjustment disorders (19%), major affective disorders (6%), psychological factors affecting physical condition (5%) and dysthymic disorder (3%). Only one subject sought professional help from a psychiatrist for relief of mental complaints. The data suggest the severity of mental ill health in software engineers, but methodological limitations preclude a firm conclusion at this time. Further studies should be made on the mental health state in software engineers.

Adult↗

PubMed1990

[Mental health in software engineers. II. Classification of occupational stressors, and relationship between occupational stressors and psychiatric disorders].

Occupational stressors and psychiatric disorders were studied in a sample of 101 male software engineers. Psychiatric diagnosis was based on DSM-III (Diagnostic and Statistical Manual of Mental Disorders, Third Edition). The results can be summarized as follows: 1) More than 30% of the subjects were not satisfied with their work. 2) Occupational stressors ascertained in the interview could be classified into "quantity of job," "quality of job," "role in organization," "relations with others," "work conditions," "career development," "reward," "organizational structure and climate," "low social support," and "lack of decision making." "quality of job" (35%), "quantity of job" (30%), and "role in organization" (33%) were the most common stressors for the subjects. 3) Among the occupational stressors, only "quantity of job" was significantly related to psychiatric disorders (p less than 0.05). The results suggest that many software engineers are not satisfied with their work and that "quantity of job" has the greatest influence on their mental health. Some measures should be taken to avoid potential health hazards, for the research findings indicate a relationship between occupational stressors and mental health in software engineers.

Adult↗

PubMed1990

Cosinor analysis of changes in circadian blood pressure rhythm with aging in spontaneously hypertensive rats.

Evolution of circadian rhythm of blood pressure with age in male spontaneously hypertensive rats (SHR) was compared with that in male Wistar Kyoto rats (WKY). Three different age groups (5-6 week old, 19-22 week old, 29-31 week old) were provided for each strain. Chronogram and cosinor method were used for time series analyses. In all age groups of WKY, a diurnal fall and a nocturnal rise in blood pressure (BP) as well as in heart rate (HR) were observed. There was no significant difference in acrophase between BP and HR in each age group of WKY. Regarding SHR, however, each age group demonstrated a different relation between circadian BP rhythm and HR rhythm. In 5-6 week old SHR, a difference in acrophase between BP and HR (about 6.9 hr, p less than 0.1) was observed, which became more conspicuous with the increase in age, eventually presenting an inverted relation between BP and HR in 19-22 week old SHR. The relation between circadian BP rhythm and circadian HR rhythm in 29-31 week old SHR was almost identical with that in 19-22 week old SHR. In other words, a phase lag of acrophase of BP from that of HR already observed in young SHR increased with aging. The results indicate that parasympathetic periodicity remained unchanged even in SHR since circadian HR rhythm was similar in all groups, while the periodicity of sympathetic neural tone relating to the regulation of circadian BP rhythm seems to be disturbed. The mechanism responsible for development and maintenance of high BP in SHR may be linked to a disturbance in the sympathetic mechanism which regulates BP periodicity.

Aging↗

PubMed1990

Influence of age on the nocturnal fall of blood pressure and its modulation by long-acting calcium antagonists.

The clinical significance of the nocturnal fall of blood pressure (BP) was examined. BP was monitored every 5 min for 24 hrs by means of a finger volume oscillometric device. The nocturnal fall was observed in all age groups (young: less than 40, n = 49; adult: 40 less than or equal to less than 60, n = 110; old: 60 less than or equal to, n = 33). The amplitude of nocturnal fall of BP (averaged daytime blood pressure--averaged nighttime blood pressure) in old patients (systolic = 13 +/- 11, diastolic = 10 +/- 8 mmHg, mean +/- SD) was similar to that in the young patients (systolic = 11 +/- 8, diastolic = 10 +/- 8 mmHg). These 192 subjects were also classified according to mean BP level (MBP) averaged for daytime in the ambulatory blood pressure monitoring records [MBP less than 85 (mmHg), n = 31; 85 less than or equal to MBP less than 100, n = 72; 100 less than or equal to MBP less than 115, n = 49; 115 less than or equal to MBP, n = 25]. BP level did not affect the pattern of circadian variation in the normal subjects or in the essential hypertensive patients at WHO stage I or II. The amplitude of the nocturnal fall in systolic BP increased with the increase in BP level, but this was not the case with diastolic BP (mean daytime BP less than 85 mmHg: systolic = 11 +/- 8, diastolic = 8 +/- 6 mmHg; 85 less than or equal to less than 100: systolic = 14 +/- 8, diastolic = 11 +/- 6 mmHg; 100 less than or equal to less than 115: systolic = 17 +/- 9, diastolic = 11 +/- 8; 115 less than or equal to: systolic 17 +/- 8, diastolic = 11 +/- 6 mmHg). Nitrendipine (8.6 +/- 5.6 mg, 22.5 +/- 11.4 days, n = 14) and nisoldipine (9.3 +/- 6.2 mg, 21.5 +/- 11.4 days, n = 15) administered once daily in the morning or nifedipine slow release tablet, 20 mg twice daily (n = 15, 17.7 +/- 5.2 days) induced a significant downward shift in the circadian BP pattern, in other words, the hypotensive effect was also observed during the night when the BP had already been low. Taken together, the information on the nocturnal behavior of BP would be valuable, especially in treating aged patients with essential hypertension with a long-acting antihypertensive drug.

Aging↗

PubMed1990

A cross-sectional survey of home blood pressure in a rural community in northern Japan.

A cross-sectional survey was performed on home blood pressure recordings (home BP) in a rural community in northern Japan. In total, 1190 participants (495 men and 695 women which consist 61.5% of the greater than or equal to 15 year-old regional population, n = 1933) were asked to measure home BP every morning for a month, using a semiautomatic BP measuring device. The actual measurements were done 16.8 +/- 10.2 times (mean +/- SD) for men and 19.0 +/- 9.4 times for women. Home systolic (SBP) and diastolic BP (DBP) was elevated gradually with age in both sexes, although DBP tended to fall after reaching 70 years old in men. SBP and DBP thus measured were significantly lower than those of casual BP of ordinary Japanese people reported by the Ministry of Health and Welfare, Japan, by 11.4 +/- 4.3 mmHg SBP (mean +/- SD) and 5.9 +/- 1.6 mmHg DBP in men, and 12.7 +/- 5.1 mmHg SBP and 8.1 +/- 2.5 mmHg DBP in women. When WHO criteria were applied to the home BP, 2.8% of men and 0.6% of women were considered to be definitely hypertensive, and 7.9% of men and 6.4% of women as of borderline cases, indicating the underestimation of hypertensive population by means of home BP. Based on these data, we demonstrated the values equal to 1SD or 2SDs above the mean in each age group to tentatively determine biological normalcy. It is necessary to define the relationship between home BP and target organ disease or hypertensive complications. A long-term prospective study is also necessary to define the relationship between home BP and long-term morbidity or mortality.

Adolescent↗

PubMed1990

Failure to visualize bilateral adrenal glands in a patient with primary aldosteronism.

Failure to visualize either adrenal gland by adrenal imaging was experienced in a patient with biochemical evidence of primary aldosteronism. Visualization of the adrenal glands was not possible after the administration of ACTH-Z (1 mg/day) for 3 days. The administration of ACTH and dexamethasone elicited an increase in blood pressure. Although the reason for this failure to visualize the adrenal glands by scanning and for the rise in blood pressure brought on by ACTH and dexamethasone remain unclear, we think that the case herein reported is a rare type of primary aldosteronism.

Adosterol↗

PubMed1990

New method of treatment for dentin hypersensitivity by precipitation of calcium phosphate in situ.

The hydrodynamic theory is generally accepted as an explanation of hypersensitive dentin and suggests that occlusion of exposed dentinal tubules should result in a reduction of hypersensitivity. We tried to block tubules by in situ precipitation of insoluble calcium phosphate. Calcium phosphate crystals precipitated in situ on patent dentin surfaces and formed in the tubules immediately upon serial application of sodium phosphate and calcium chloride solutions, thus occluding the tubules. The size of crystals, their degree of coverage, and the thickness of the precipitate depended on the method of application and concentration of the solutions. The application of 5% disodium phosphate solution followed by rubbing with 10% calcium chloride solution resulted in immediate relief from dental hypersensitivity in 84% of patients treated.

Adult↗

PubMed1990

[Pulmonary artery banding for double inlet left ventricle].

Thirteen patients with double-inlet left ventricle who had undergone pulmonary artery banding (PAB) were reviewed. At the time of PAB, the age ranged from 2 months to 3 years. Pulmonary-systemic arterial pressure ratio and pulmonary arterial mean pressure were reduced from 0.95 +/- 0.12 to 0.4 +/- 0.18, and from 57.3 +/- 11.6 mmHg to 29.9 +/- 12.7 mmHg after PAB. Pulmonary resistance showed no statistically significant change after PAB. (from 7.6 +/- 5.2 unit to 4.8 +/- 3.9 unit) Ventricular end-diastolic volume decreased from 379.9% +/- 140.0% to 275.7% +/- 118.0% after PAB. The smallest one was 170% who successfully underwent septation procedure. Ejection fraction significantly decreased from 64.5 +/- 6.1% to 56.3 +/- 7.9%. (p less than 0.005) Ventricular end-diastolic pressure showed no significant change after PAB. (from 9.2 +/- 2.8 mmHg to 9.9 +/- 2.0 mmHg) After PAB subaortic stenosis occurred in three cases and pressure gradient were 10, 20, and 85 mmHg, respectively. Seven cases, including three cases with subaortic stenosis, underwent septation procedure and all survived. Before septation, ventricular end-diastolic volume calculated as % of normal left ventricular volume ranged from 173% to 570% and pulmonary resistance ranged from 1.6 unit to 11 unit. These data suggested that the patients with double-inlet left ventricle had efficient ventricular volume and cardiac function for septation even after PAB.

Child, Preschool↗