PubMed Health⌕ Search

Biomedical subjects

C Tei

Publications and source records attributed to C Tei.

At least 91 records · Page 5Linked to original sources
PubMed1995

Effect of ophthalmic preservatives on serum concentration and local irritation of ocularly applied insulin.

We previously compared hypoglycemic responses after the instillation of insulin formulations. A hypoglycemic response was actually observed after an instillation of insulin with ophthalmic preservatives. In the present study, in order to evaluate the usefulness of insulin formulation containing ophthalmic preservatives, a serum concentration of insulin and an irritation to the eye were investigated after instillation of the insulin formulation in albino rabbits. The ophthalmic preservatives used were benzalkonium chloride, paraben, 2-phenylethanol, benzyl alcohol and sorbic acid. As a result, ophthalmic preservatives, especially benzalkonium chloride and paraben, increased the serum concentration of insulin. The insulin concentration showed a significant correlation with the hypoglycemic response reported previously. This result indicates that ophthalmic preservatives increase the absorption of ocularly applied insulin, and the absorbed insulin decreases serum glucose concentration. The insulin formulation with preservatives showed little irritation on rabbit eyes according to blinking measurements. These results indicate that ophthalmic preservatives are useful for the systemic delivery of ocularly applied insulin.

Administration, Topical↗
PubMed1995

Ocular permeability of FITC-dextran with absorption promoter for ocular delivery of peptide drug.

The purpose of this study is to characterize an ocular permeability of FITC-dextran, as a model of peptide drug, and to evaluate the effects of absorption promoters on the ocular permeability of FITC-dextran. The in vitro penetrations of FITC-dextrans (average molecular weight 4400 and 9400: FD-4 and FD-10) were measured across the isolated corneal and conjunctival membranes of albino rabbits using a two-chamber glass diffusion cell. The corneal permeabilities of FD-4 and FD-10 were much lower than the conjunctival permeabilities. Scraping of corneal epithelium extremely increased the corneal permeabilities. The penetration parameters were estimated according to Fick's equation. Absorption promoters such as EDTA, taurocholic acid, benzalkonium chloride and saponin significantly increased corneal permeabilities of FD-4 and FD-10. Saponin showed the highest promoting activity. Conjunctival permeabilities of FD-4 and FD-10 were also enhanced by absorption promoters although the improvements of conjunctival permeabilities by absorption promoters were smaller than those of corneal permeabilities. Ratios of corneal to conjunctival permeabilities were enhanced by absorption promoters. These results indicate that an ocular delivery of instilled hydrophilic macromolecule is markedly low and a selective use of absorption promoter can improve the extent and pathway of its ocular absorption.

Absorption↗
PubMed1995

Assessment of myocardial viability in chronic left ventricular dysfunction.

Differentiation of infarcted from viable myocardium is of critical clinical importance in patients with severely impaired left ventricular function. While positron emission tomography is considered the "gold-standard" modality for detection of viable myocardium, expense has limited its more widespread use. Therefore, many centers employ surrogate tests for metabolic viability. In several recent studies, low-dose dobutamine echocardiography has been useful in predicting recovery of poorly contractile myocardium. Myocardial contrast echocardiography is a promising new technique which may predict viability by defining areas of preserved microvascular integrity. The clinical role of these diagnostic modalities in the setting of depressed ventricular function is as yet uncertain. Clarification of the utility of these tests should allow more judicious selection of patients who would derive the greatest survival benefit from revascularization procedures.

Chronic Disease↗
PubMed1995

New index of combined systolic and diastolic myocardial performance: a simple and reproducible measure of cardiac function--a study in normals and dilated cardiomyopathy.

BACKGROUND: Because systolic and diastolic dysfunction frequently coexist, it is hypothesized that a combined measure of left ventricular chamber performance may be more reflective of overall cardiac dysfunction than systolic or diastolic measures alone. METHODS Study patients consisted of 170 subjects: 70 normals, 47 patients with severe dilated cardiomyopathy in NYHA class III-IV awaiting cardiac transplantation and 53 patients with idiopathic dilated cardiomyopathy of intermediate severity [NYHA class II, ejection fractions (EF) 30-50%]. EF, stroke volume and cardiac indexes were measured using conventional echo-Doppler methods. Pre-ejection period/ejection time (PEP/ET), isovolumetric relaxation time (IRT), isovolumetric contraction time/ET (ICT/ET) were also measured. A new derived index of myocardial performance: (ICT+IRT)/ET, was obtained by subtracting ET from the interval between cessation and onset of the mitral inflow velocity to give the sum of ICT and IRT. RESULTS The index was easily measured, reproducible, and had a narrow range in normals. The mean value of the index was significantly different between normal, intermediate and pre-transplant subjects (0.39 +/- 0.05, 0.59 +/- 0.10 and 1.06 +/- 0.24, respectively, p < 0.001 for all comparisons). The degree of inter-group overlap was smaller for the index compared to PEP/ET, ICT/ET and other parameters. Within functional groups, the value of the index did not appear to be related to heart rate, mean arterial pressure and the degree of mitral regurgitation. CONCLUSION (ICT+IRT)/ET is a conceptually new, simple and reproducible Doppler index of combined systolic and diastolic myocardial performance in patients with primary myocardial systolic dysfunction.

Adult↗
PubMed1994

Effect of preservatives on systemic delivery of insulin by ocular instillation in rabbits.

The effects of absorption promoters and ophthalmic preservatives on the systemic absorption of insulin through the ocular route were investigated in albino rabbits. Insulin absorption was evaluated by its hypoglycaemic response. Although ocular instillation of insulin alone did not decrease the serum glucose concentration, instillation of insulin with absorption promoters such as EDTA and saponin decreased it. The promoting effect depended on the concentration of the absorption promoters. Of ophthalmic preservatives investigated (benzalkonium chloride, paraben, 2-phenylethanol, benzyl alcohol and sorbic acid), benzalkonium, chloride and paraben showed promoting effects. The promoting effect for benzalkonium chloride was reversible and dependent on concentration of both benzalkonium chloride and insulin in the formulation.

Absorption↗
PubMed1992

Obstruction of inferior vena caval orifice by giant left atrium in patients with mitral stenosis. A Doppler echocardiographic study from the right parasternal approach.

BACKGROUND: To examine whether an extremely enlarged left atrium (giant left atrium) obstructs the venous return from the inferior vena cava (IVC), the velocity of IVC flow was measured at its junction with the right atrium (IVC orifice) in patients with mitral stenosis by use of color and pulsed-wave Doppler echocardiography from a right parasternal longitudinal plane. METHODS AND RESULTS: The maximum dimension of the IVC orifice by two-dimensional echocardiography and the maximum IVC orifice flow velocity by pulsed-wave Doppler echocardiography were measured in 74 patients with mitral stenosis and atrial fibrillation (mean age, 59 years). The control population consisted of 16 subjects with atrial fibrillation alone (mean age, 61 years). Flow velocities in the superior vena cava and hepatic vein were also obtained by pulsed-wave Doppler echocardiography from the supraclavicular and subcostal views, respectively. Fifty-one mitral stenosis patients without severe tricuspid regurgitation were divided into two groups according to the left atrial dimension (LAD), which was measured by the standard left parasternal long-axis view (group A: n = 33, LAD less than 65 mm; group B: n = 18, LAD greater than or equal to 65 mm). Peak inspiratory and expiratory velocities of IVC orifice flow in diastole averaged over three consecutive inspirations in group B (mean +/- SD, 93.4 +/- 32.0 and 47.6 +/- 19.8 cm/sec) were significantly greater (p less than 0.01) than in the control subjects (67.9 +/- 12.8 and 34.5 +/- 7.0 cm/sec) and in group A (70.2 +/- 18.4 and 38.1 +/- 11.5 cm/sec, respectively). However, there were no significant differences in superior vena caval and hepatic vein flow velocities among the three groups. The maximum IVC orifice dimension in group B (11.4 +/- 4.4 mm) was significantly smaller than in the control subjects (20.1 +/- 2.1 mm) and in group A (18.6 +/- 5.4 mm) because of displacement of the atrial septum into the right atrium. There were significant negative correlations between the IVC orifice dimension and the peak IVC orifice flow velocity (r = -0.62, SEE = 0.33 cm/sec, n = 67, y = e(-0.01x + 3.6), p less than 0.01) as well as the left atrial dimension (r = -0.71, SEE = 0.32 mm, n = 67, y = e(-0.02x + 3.8), p less than 0.01) in these 51 patients and control subjects. In the remaining 23 patients with severe tricuspid regurgitation, the peak inspiratory IVC orifice velocity (n = 9, 88.6 +/- 30.0 cm/sec) was significantly greater (p less than 0.05) and the IVC orifice dimension (23.8 +/- 9.7 mm) significantly smaller (p less than 0.05) in patients with a giant left atrium than in those without (n = 14, 69.9 +/- 15.3 cm/sec and 30.5 +/- 9.6 mm, respectively); in the latter, the IVC orifice dimension was significantly (p less than 0.05) greater than in the controls. CONCLUSIONS: A giant left atrium in patients with mitral stenosis obstructs venous return at the IVC orifice by marked displacement of the atrial septum toward the right atrium.

Adult↗
PubMed1992

A simple noninvasive measurement of stenotic mitral valve area: an alternative approach using M-mode and Doppler echocardiography.

Doppler echocardiography is a widely used noninvasive technique to examine the mitral valve area (MVA) by obtaining mitral pressure half-time (PHT) and to assess the severity of the stenosis. However, several hemodynamic factors influence the PHT and may render the PHT data inaccurate in any measurement of MVA under certain conditions. Using a simple echo-Doppler (E-D) method, we assessed the MVA in a physiological equation. The mitral flow volume (MFV) is represented by MVA x transmitral mean flow velocity (mV) x diastolic filling time (DFT). Thus, the formula can be restated as MVA (cm2) = MFV (cm3)/mV (cm/sec) x DFT (sec). We measured MFV by M-mode, and mV and DFT by continuous wave Doppler echocardiography. This formula was tested in 43 patients with isolated mitral stenosis. MVA was obtained by the PHT and E-D methods, and the data obtained were validated against the results of cardiac catheterization. The results obtained using the E-D method showed much better correlation (r = 0.82) with those of catheterization than those with the PHT method (r = 0.52). The inter- and intraobserver variabilities were checked. The results obtained with the E-D method were found to be reproducible. To further validate the accuracy of the E-D method, MVA was measured by both methods at different R-R intervals after exercise and the results were compared. The MVA obtained by the PHT method showed marked variations; whereas, that obtained by the E-D method remained nearly constant. Similarly, in a patient with atrial fibrillation, the MVA assessed by the PHT method varied from beat to beat; whereas, the fluctuations in MVA were minimal using the E-D method. We concluded that the E-D method can be reliable and clinically easily applicable for the accurate assessment of MVA.

Adult↗
PubMed1991

[Pulmonary venous flow patterns in normal subjects and cardiac patients: a transesophageal echocardiographic study].

The aim of this study is, first, to analyze pulmonary venous flow velocity (PVFV) pattern in normal subjects and second, to compare it with the various diseased state. PVFV was recorded in eleven normal volunteers, five patients with lone atrial fibrillation, twenty eight patients with valvular heart diseases and six patients with cardiomyopathy using transesophageal color Doppler echocardiography by placing the sample volume at the junction of the left superior pulmonary vein and left atrium. PVFV in normal subjects demonstrated distinct four waveforms: due to atrial systole (AS wave) and diastole (AD wave), and due to ventricular systole (VS wave) and diastole (VD wave). PVFV changed with respiration in normal subjects. The peak velocity of VD wave was increased with inspiration (p less than 0.001). The ratio of velocity VS/VD was increased during expiration (p less than 0.01). The ratio of area AD + VS/VD was significantly decreased with inspiration (p less than 0.01). We feel that this is the normal variation in pulmonary venous return during respiration , influenced by changes in the venous return on the right side of the heart. In all patients with atrial fibrillation, AS and AD waves were disappeared. The negative deflection occasionally observed was due to mitral valve closure. In patients with mitral stenosis, the peak velocity of VD wave was significantly decreased compared to that of normal subjects, but it was not significantly different between the patients with mitral valve replacement and normal subjects. The peak velocity of VD wave was also correlated with pressure half time among the patients with mitral stenosis, mitral valve replacement and mitral commissurotomy. On the other hand, it was significantly increased in patients with mitral regurgitation and returned to normal level after the operation. The peak velocity of VS wave was correlated with the left atrial dimension among the patients with mitral valve diseases except these with mitral regurgitation. In patients with mitral regurgitation, the peak velocity was decreased compared to that of normal subjects and reversed flow was seen in half of the patients. Also, it was decreased in patients with dilated cardiomyopathy and increased in patients with hypertrophic cardiomyopathy. In conclusion, PVFV is influenced not only by changes of venous return with respiration but also by the left atrial size, presence or absence of MS or MR, left atrial or left ventricular systolic and diastolic function in the various diseased states.

Adult↗
PubMed1990

[Mental stress echocardiography for patients with mitral valve prolapse].

Our clinical experience suggests that anxiety may provoke the augmentation of the degree of mitral valve prolapse (MVP) and change the mitral inflow velocity pattern in patients with MVP. To evaluate this systematically, we recorded 2-dimensional (2-D) and pulsed wave Doppler echocardiograms during acute mental stress in eight patients with MVP and eight age-matched normal subjects. Acute mental stress was administered by applying arithmetical task or reminding each patient of their most uncomfortable memories. Heart rate and blood pressure were significantly increased during mental stress and returned to the control level within a few minutes after its release in both groups. 2-D and Doppler echocardiograms were constantly recorded before, during and after acute mental stress. MVP was prominently augmented during mental stress in three of the eight patients. During mental stress, the mitral inflow velocity decreased in the rapid filling phase (R) and increased in the atrial filling phase (A), resulting in significant increase of the A/R in seven of the eight patients with MVP, especially in the patients associated with an increase of MVP. In normal subjects, mitral valve prolapse did not develop and the A/R was minimally increased or remained almost the same during mental stress. In conclusion, mental stress echocardiography seems to be a useful provocation test for the assessment of MVP and it is further expected to propose a lot of potential applications as a new method of stress echocardiography.

Adult↗
PubMed1989

Gastrin-releasing peptide-like immunoreactivity in porcine follicular fluid and ovary.

Porcine follicular fluid was found to contain gastrin-releasing peptide (GRP) by radioimmunoassay. High pressure liquid chromatography of the extracted material showed two peaks of GRP immunoreactivity that closely resembled the C-terminal fragments of GRP, GRP18-27 and GRP14-27. Immunohistochemical studies revealed specific staining for GRP in the granulosa cells of adult porcine ovary. These results demonstrate the presence of substances which behave like authentic GRP-like peptides in porcine ovary and follicular fluid and suggest that these peptides may play a paracrine and/or autocrine role in the regulation of the ovarian function.

Animals↗
PubMed1989

[Continuous wave Doppler echocardiographic evaluations of the severity of mitral regurgitation].

To ascertain the usefulness of continuous wave Doppler echocardiography in evaluating the severity of mitral regurgitation (MR), 29 patients with MR and 10 normal subjects were examined. The patients were categorized in three groups according to the angiographic evidence of severity of MR. To analyze the flow velocity patterns of MR, the time to peak velocity index (time from onset of MR signal to peak flow velocity/duration of MR signal), the A/B ratio (the ratio of the first and second half of the systolic MR signal area), systolic peak velocity, and diastolic peak velocity were measured using continuous wave Doppler echocardiograms. The velocity patterns of MR differed significantly among the three groups. With severer MR, the flow velocity pattern showed an earlier appearance of the peak in systole, a steeper decrease in systole and a greater increase in early diastole. The time to peak velocity index was 55 +/- 7% (mean +/- SD) in mild MR, 42 +/- 6% in moderate MR and 35 +/- 5% in severe MR. This index shortened significantly in accord with the severity of MR (mild vs moderate MR: p less than 0.001, moderate vs severe MR: p less than 0.05). The A/B ratio was 1.06 +/- 0.12 in mild MR, 1.23 +/- 0.10 in moderate MR and 1.41 +/- 0.07 in severe MR. This ratio increased significantly with the severity of MR (mild vs moderate MR: p less than 0.01, moderate vs severe MR: p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Echocardiographic observations of calcium in operatively excised stenotic aortic valves.

Qualitative and quantitative 2-dimensional (2-D) echocardiographic methods were developed to define the anatomic and physiologic significance of valvular calcium in aortic stenosis (AS). Qualitative methods assigned etiologic diagnoses by matching patterns of calcium with anatomic criteria. Quantitative techniques measured echodensities from superimposed short-axis views of calcium. Fifty-five pathologic specimens procured from surgery were photographed and radiographed. Etiologic diagnoses were assigned from gross examination and radiodensities were planimetered. Echocardiographic and anatomic diagnoses were compared. Sensitivities for diagnosing the most common etiologies, congenitally bicuspid and degenerative, were 58% and 100% and specificities were 100% and 76%. Calcium tended to be heaviest in congenitally diseased valves and lightest in those with degenerative disease (p less than 0.2) and showed propensity for the right cusp in all etiologies except for those with degenerative disease. Correlation of echodensities to radiodensities was 0.82. The relation of calcific echodensities to orifice area was curvilinear; beyond a level of calcium, further deposits did not reduce the orifice more. A systematic echocardiographic examination of calcium in stenotic aortic valves can give a correct etiologic diagnosis in most patients and identify the severely narrowed orifice.

Adult↗
PubMed1987

Color Doppler echocardiographic assessment of the change in the mitral regurgitant volume.

We studied the possibility that a mitral regurgitant Doppler signal area on a two-dimensional color Doppler echocardiogram can reflect changes in mitral regurgitant volume in 24 patients with several types of mitral regurgitation. In 20 patients, mitral regurgitant Doppler signal areas were clear enough to measure. Injections of phenylephrine were given to these patients during the recording of the mitral regurgitant Doppler signal area in the same views and with the same Doppler gains. The mitral regurgitant Doppler signal area, blood pressure, and heart rate were measured before and after phenylephrine provocation. In addition, inhalation of amyl nitrite was performed during the recording of the mitral regurgitant Doppler signal area in the same way. Injection of phenylephrine resulted in an increase in the mitral regurgitant Doppler signal area accompanied by an increase in blood pressure and a decrease in heart rate. On the other hand, inhalation of amyl nitrite resulted in a decrease in the mitral regurgitant Doppler signal area, a decrease in blood pressure, and an increase in heart rate. A positive correlation between the change in blood pressure and that in the mitral regurgitant Doppler signal area was observed. In conclusion, two-dimensional color Doppler echocardiography may be useful in the assessment of the acute change in regurgitant volume in the patient with mitral regurgitation.

Adult↗
PubMed1987

[Assessment of perfusion defects by intracoronary myocardial contrast echocardiography].

Myocardial contrast echocardiography has developed rapidly in the last few years. This paper is a review of this method based on our previous studies performed in 43 closed chest dogs. An injection of 2 ml of an agitated saline-Renografin mixture into the left main coronary artery provided contrast opacification of the entire circumference of the left ventricular myocardium. Contrast injection into the left anterior descending or the circumflex artery resulted in contrast opacification of localized regions of the left ventricle. Contrast injection into the left main coronary artery after a selective coronary artery occlusion resulted in a "negative" contrast outline of the corresponding area indicating the underperfused myocardium. The physiological and hemodynamic effects of the intracoronary injection of the contrast material appeared minor and brief. Perfusion defects after coronary artery occlusion assessed by myocardial contrast echo correlated well with those in equivalent sections by monastral blue dye injected into the left ventricle. Furthermore, the extent of myocardial necrosis after five hours of coronary occlusion assessed by myocardial contrast echo correlated well with the area of necrotic myocardium in equivocal slabs. Myocardial contrast washout index (T1/2) measured by digital intensity analysis of successive end-diastolic images was found to be significantly changed in dogs with varying degrees of coronary stenosis. Thus, the measurement of T1/2 appears to be feasible for evaluating degree of coronary stenosis, however, numerous technical problems remain to be clarified.

Animals↗
PubMed1987

[Two-dimensional contrast echocardiographic assessment of the time course of regional ischemic myocardial function].

The time course of percent fractional area change (%FAC) of the ischemic left ventricular wall as identified by myocardial contrast echocardiography was assessed. Two-dimensional echocardiograms of the left ventricular short axis at the level of the chordae tendineae were recorded in 16 anesthetized open-chest dogs. Myocardial ischemia was produced by occluding the left circumflex coronary artery (LCX) for 30 min, and identified by myocardial contrast echocardiography using aortic root contrast injection. The left ventricular wall in the short-axis view was divided into eight segments. The experiments were completed in nine dogs. The %FAC of the segment which includes the center of the ischemic area was normal before LCX occlusion (35 +/- 6%: mean +/- S.D.), markedly decreased during 30 min of LCX occlusion (-3 +/- 4%) and gradually recovered after coronary reperfusion. However, it was significantly decreased 150 min after reperfusion (8 +/- 9%) (p less than 0.001) compared to that before LCX occlusion. The %FAC of the segment which includes the center of the non-ischemic area was not significantly changed throughout the experiment. In conclusion, 1) the time course of regional ischemic myocardial function could be assessed by the analysis of the %FAC of the ischemic area determined by myocardial contrast echocardiography, 2) the %FAC is significantly decreased 150 min after coronary reperfusion following 30 min occlusion compared to that before coronary occlusion.

Animals↗