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Biomedical subjects

S Kaji

Publications and source records attributed to S Kaji.

At least 37 records · Page 2Linked to original sources
PubMed1998

Restricted coronary flow reserve in patients with mitral regurgitation improves after mitral reconstructive surgery.

OBJECTIVES: The purpose of this study was to assess coronary flow characteristics in patients with chronic mitral regurgitation (MR). BACKGROUND: Coronary flow reserve (CFR) has been reported to be restricted in cases with left ventricular (LV) volume overload caused by aortic regurgitation and increased LV preload. METHODS: The study populations consisted of 31 patients with nonrheumatic chronic MR. Eleven with chest pain and normal coronary arteries served as control subjects. Phasic coronary flow velocities were obtained in the proximal segment of the angiographically normal left anterior descending coronary artery at rest and during hyperemia (0.14 mg/kg/min adenosine infusion intravenously) using a 0.014-in. (0.036 cm), 15-MHz Doppler guide wire. Coronary flow reserve was obtained from the ratio of hyperemic/baseline time-averaged peak velocity (APV). Thirteen cases who underwent mitral valve reconstructive surgery were also studied 1 month after surgery. RESULTS: Compared with control subjects, CFR was significantly reduced in cases with MR (2.1+/-0.5 vs. 33+/-0.6, respectively, p < 0.01) because baseline APV was significantly greater (28+/-8 vs. 19+/-6 cm/s, respectively, p < 0.01), although maximal hyperemic APV was not significantly different (56+/-14 vs. 61+/-16 cm/s, respectively, p = NS). Significant correlations were obtained between CFR and LV end-diastolic pressure (LVEDP) (r = 0.70, p < 0.01), LV mass index (r = 0.42, p < 0.01), LV end-diastolic volume (r = 038, p = 0.04) and MR volume (r = 0.39, p = 0.03), and stepwise regression analysis showed LVEDP was the most important determinant of CFR in MR (r2 = 0.49, p < 0.0001). This restricted CFR improved significantly after mitral valve reconstructive surgery (2.1+/-0.5 vs. 3.1+/-0.6, respectively, p < 0.01) because of reduction of baseline APV (28+/-8 vs. 21+/-8 cm/s, respectively, p < 0.01). CONCLUSIONS: Coronary flow reserve is limited in cases with MR because of elevation of baseline resting flow velocity. This reduction of CFR correlates well with increase in LV preload, mass and volume overload, especially with increase in LV preload, and this restricted CFR improves after mitral valve surgery.

Adult↗
PubMed1998

[Automated cardiac output measurement by color Doppler echocardiography].

Recently, automated cardiac flow measurement (ACM) has been developed for measuring the volume flow rate of blood flow through the left ventricular outflow tract. Measurements of left ventricular cardiac output by the ACM method were compared with those by the thermal dilution method with a Swan-Ganz catheter in 27 patients (16 men and 11 women; aged 44 +/- 3 years) in whom clear two-dimensional and color Doppler images of the left ventricular outflow tract were obtained. The total time required for left ventricular stroke volume calculation by both ACM and pulsed Doppler methods was measured in 10 patients (six men and four women; aged 41 +/- 2 years). There was an excellent correlation in the measurements of cardiac output between the ACM and thermal dilution methods (y = 0.77x + 0.77, r = 0.84, SEE = 0.4 l/min). The total time required for left ventricular stroke volume calculation by the ACM method was significantly shorter than that by the pulsed Doppler method (92 +/- 10 vs 177 +/- 30 sec, p < 0.01). The ACM method is simple, quick, and accurate for the automated assessment of cardiac output.

Adult↗
PubMed1998

[Assessment of coronary flow reserve in patients with hypertrophic cardiomyopathy using transthoracic color Doppler echocardiography].

Abnormal coronary flow pattern and coronary vasodilator reserve have been identified in patients with hypertrophic cardiomyopathy (HCM) using invasive techniques. The characteristics of coronary flow velocity and coronary flow reserve were evaluated by noninvasive-recording of coronary flow velocity in the distal portion of the left anterior descending coronary artery in 7 patients with HCM and 7 normal subjects using transthoracic color Doppler echocardiography. Coronary flow velocity was measured at rest and during intravenous infusion of adenosine triphosphate (0.15 mg/kg/min). Diastolic peak velocity, diastolic mean velocity, the time from the beginning of diastole to peak velocity (TVP) and velocity half time from peak velocity was measured in each group. Coronary flow reserve was obtained as the ratio of hyperemic mean velocity to resting mean velocity. TVP was significantly prolonged in the patients with HCM compared with the normal subjects (159 +/- 38 vs 103 +/- 54 msec, p < 0.05). Velocity half time was significantly shorter in the patients with HCM compared with the normal subjects (304 +/- 138 vs 451 +/- 109 msec, p < 0.05). Although diastolic mean velocity during hyperemia was not different between the 2 groups (62 +/- 8 vs 70 +/- 19 cm/sec), diastolic mean velocity at rest was significantly higher in the patients with HCM than in the normal subjects (39 +/- 6 vs 26 +/- 7 cm/sec, p < 0.01). Therefore, coronary flow reserve was significantly lower in the patients with HCM than in the normal subjects (1.6 +/- 0.4 vs 2.7 +/- 0.4, p < 0.001). There was a good correlation between diastolic mean velocity and the ratio of interventricular septal to posterior left ventricular wall thickness (y = 0.024x + 0.46, r = 0.75). Transthoracic assessment of coronary flow velocity using color Doppler echocardiography reveals that coronary flow reserve is reduced in patients with HCM because of increased baseline resting diastolic mean velocity.

Cardiomyopathy, Hypertrophic↗
PubMed1997

Comparison of coronary flow reserve between focal and diffuse vasoconstriction induced by ergonovine in patients with vasospastic angina.

Decreased coronary flow reserve has been reported in patients with ergonovine-induced coronary vasoconstriction by the thermodilution method. To assess the difference of coronary flow reserve between patients with focal and diffuse vasospasm, after the vasospasm is discontinued by injection 3 mg of isosorbide dinitrate, phasic flow velocities of the diseased coronary artery were recorded at rest and during hyperemia (140 microg/kg/min of adenosine infusion intravenously) using a 0.014-inch, 15-MHz Doppler guidewire in 26 patients with ergonovine-induced coronary vasospasm (0.2-mg ergonovine injection intravenously), including 12 patients with focal (>90% stenosis), 14 patients with diffuse vasospasm (>50%), and 11 controls with normal coronary arteries without vasospasm. Although time-averaged peak velocity in cases with diffuse and focal vasospasm was not significantly different compared with that in controls at baseline (22 +/- 7, 18 +/- 5 vs 20 +/- 7 cm/s, respectively, NS), it was significantly lower in patients with diffuse vasospasm than in cases with focal vasospasm and in controls during hyperemia (43 +/- 13 vs 64 +/- 18, 61 +/- 19 cm/s, respectively, p <0.01). As a result, coronary flow reserve obtained from the ratio of hyperemic/baseline time-averaged peak velocity was significantly lower in patients with diffuse vasospasm than that in controls (1.9 +/- 0.4 vs 3.1 +/- 0.4, p <0.01), although it was not significantly different between the subjects with focal vasospasm and controls (3.5 +/- 0.7 vs 3.1 +/- 0.4, NS). Thus, coronary flow reserve is maintained normally in patients with focal vasospasm and limited in those with diffuse vasospasm. Microvascular impairment could exist further in cases with diffuse vasospasm, although similar endothelial dysfunction of the epicardial coronary artery is observed in focal and diffuse vasospasm.

Adult↗
PubMed1997

Retinopathy identifies marked restriction of coronary flow reserve in patients with diabetes mellitus.

OBJECTIVES: This study sought to assess the differences in coronary flow reserve in patients with and without diabetic retinopathy. BACKGROUND: Microvascular abnormalities throughout the body and impairment of coronary flow reserve have been described in patients with diabetes mellitus. However, the relation between diabetic retinopathy and coronary microvascular disease has not been investigated. METHODS: The study included 29 patients with diabetes mellitus (18 with and 11 without diabetic retinopathy) and 15 control patients with chest pain and normal coronary arteries. Diabetic retinopathy was nonproliferative in all 18 patients with this disorder (8 had background, 10 preproliferative retinopathy). Five minutes after injection of 3 mg of isosorbide dinitrate, phasic flow velocities were recorded in the proximal segment of the angiographically normal left anterior descending coronary artery at rest and during hyperemia (0.14 mg/kg body weight per min of adenosine infused intravenously) using a 0.014-in. 15-MHz Doppler guide wire. Coronary blood flow was calculated, and coronary flow reserve was obtained from the hyperemic/baseline flow ratio. RESULTS: Coronary blood flow was significantly lower during hyperemia ([mean +/- SD] 107 +/- 23 and 116 +/- 18 vs. 136 +/- 17 ml/min, respectively) and higher at baseline (58 +/- 16 and 45 +/- 12 vs. 37 +/- 10 ml/min, respectively) in diabetic patients with and without retinopathy than in control subjects (p < 0.05 for both diabetic groups). As a result, coronary flow reserve in both groups of diabetic patients was significantly lower than in control patients (1.9 +/- 0.4 and 2.8 +/- 0.3 vs. 3.3 +/- 0.4, respectively, p < 0.01 for both diabetic groups), and its reduction was greater in patients with than without retinopathy (p < 0.01). Furthermore, in patients with diabetic retinopathy, maximal hyperemic coronary flow (102 +/- 11 vs. 114 +/- 16 ml/min, p < 0.05) and flow reserve (1.6 +/- 0.2 vs. 2.3 +/- 0.2, p < 0.01) were significantly lower in those with preproliferative than background retinopathy. CONCLUSIONS: Coronary flow reserve is significantly restricted in patients with diabetes mellitus, and its reduction is more marked in those with diabetic retinopathy, especially in advanced retinopathy. Thus, diabetic retinopathy should identify marked restriction of coronary flow reserve in patients with diabetes mellitus.

Adult↗
PubMed1997

Identification of genetic mutations in Japanese patients with fructose-1,6-bisphosphatase deficiency.

Fructose-1,6-bisphosphatase (FBPase) deficiency is an autosomal recessive inherited disorder and may cause sudden unexpected infant death. We reported the first case of molecular diagnosis of FBPase deficiency, using cultured monocytes as a source for FBPase mRNA. In the present study, we confirmed the presence of the same genetic mutation in this patient by amplifying genomic DNA. Molecular analysis was also performed to diagnose another 12 Japanese patients with FBPase deficiency. Four mutations responsible for FBPase deficiency were identified in 10 patients from 8 unrelated families among a total of 13 patients from 11 unrelated families; no mutation was found in the remaining 3 patients from 3 unrelated families. The identified mutations included the mutation reported earlier, with an insertion of one G residue at base 961 in exon 7 (960/961insG) (10 alleles, including 2 alleles in the Japanese family from our previous report [46% of the 22 mutant alleles]), and three novel mutations--a G-->A transition at base 490 in exon 4 (G164S) (3 alleles [14%]), a C-->A transversion at base 530 in exon 4 (A177D) (1 allele [4%]), and a G-->T transversion at base 88 in exon 1 (E30X) (2 alleles [9%]). FBPase proteins with G164S or A177D mutations were enzymatically inactive when purified from E. coli. Another new mutation, a T-->C transition at base 974 in exon 7 (V325A), was found in the same allele with the G164S mutation in one family (one allele) but was not responsible for FBPase deficiency. Our results indicate that the insertion of one G residue at base 961 was associated with a preferential disease-causing alternation in 13 Japanese patients. Our results also indicate accurate carrier detection in eight families (73%) of 11 Japanese patients with FBPase deficiency, in whom mutations in both alleles were identified.

Amino Acid Substitution↗
PubMed1997

Chondrocyte migration to fibronectin, type I collagen, and type II collagen.

It is well known that cellular interactions, such as cell adhesion, migration, invasion, between cells and the extracellular matrix are mediated by the integrin family of cell surface receptors. Chondrocytes are surrounded by an abundant extracellular matrix, but there is less information on the cellular receptors which interact with this matrix. In our studies, fibronectin, type I collagen, and type II collagen promoted haptotactic and chemotactic migration of chondrocytes, as determined using a modified Boyden chamber system. Treatment of chondrocytes with tyrosine kinase inhibitor, herbimycin or genistein, resulted in a dose dependent inhibition of migration toward these matrix proteins, whereas adhesion of chondrocytes was not influenced. This indicated the existence of functional relationships between protein tyrosine phosphorylation and chondrocyte migration following the adhesion of chondrocytes to matrix proteins. Further study showed that the peptide GRGDSP inhibited chondrocyte migration to fibronectin but not to collagens. On the other hand, chondrocytes migrated toward the tetra-RGD containing peptide, but not the peptide GRGDSP, in a dose dependent fashion. These observations suggest that cross-linking or clustering of integrins is essential to induce transmembrane signaling related to tyrosine phosphorylation for chondrocyte migration toward fibronectin.

Animals↗
PubMed1997

[Transthoracic digital color Doppler assessment of the left anterior descending coronary artery and intramyocardial blood flow].

Noninvasive assessment of the distal left anterior descending coronary artery and intramyocardial blood flow were attempted in 50 consecutive patients (28 males and 22 females, mean age [+/-SD] 58 +/- 12 years) using a 7.5 MHz transducer (Doppler frequency: 5 MHz) and a SSA-380A ultrasound digital system with special optimal settings for the color Doppler examination. Modified apical acoustic windows were used to visualize the blood flow in the distal left anterior descending coronary artery and the intramyocardial artery. By selecting a sample volume (2 mm wide) on the color trace of these blood flows, Doppler spectral tracing of the distal left anterior descending coronary artery and intramyocardial blood flows could be recorded using pulsed-wave Doppler system. Blood flow in the distal left anterior descending coronary artery was detected in 43 (86%, Vmax = 22 +/- 8.7 cm/sec, Vmean = 16 +/- 5.1 cm/sec) of 50 patients, and intramyocardial blood flow in 40 (80%, Vmax = 26 +/- 11.0 cm/sec, Vmean = 19 +/- 8.5 cm/sec) of 50 patients. Distal left anterior descending coronary artery and the intramyocardial blood flows can be imaged by transthoracic digital color Doppler echocardiography in the clinical setting.

Coronary Circulation↗
PubMed1997

[Measurement of plaque volume using three-dimensional intravascular ultrasound: in vitro study].

The usefulness of three-dimensional echocardiography using intravascular ultrasound (3D-IVUS) for the measurement of plaque volume was evaluated by comparing plaque volume derived from 3D-IVUS with that directly measured in 10 autopsied iliac or femoral plaque models (5-15 mm long). Using IVUS (3.5 F, 30 MHz), sequential cross-sectional images for three-dimensional datasets were acquired with a motorized catheter pullback device connected to the three-dimensional reconstruction system. Three-dimensional reconstruction was performed from the sum of the two-dimensional cross-sectional views. Plaque volumes were calculated using a summation of disks algorithm based on the reconstructed multiple short-axis cross-sections from the three-dimensional data. Three-dimensional IVUS demonstrated a good correlation with direct measurement of plaque volume (y = 0.71x + 0.001, r = 0.80, SEE = 0.003 ml), so is useful for the measurement of plaque volumes in the experimental models.

Arteriosclerosis↗
PubMed1995

Identification of a genetic mutation in a family with fructose-1,6- bisphosphatase deficiency.

Fructose-1,6-bisphosphatase deficiency is an inheritable disorder of gluconeogenesis. Sequence analysis of the cDNA of the fructose-1,6-bisphosphatase mRNA isolated from monocytes from a girl with this disease and her consanguineous parents revealed that the patient and her parents were a homozygote and heterozygotes for an insertion of one G residue at G957GGGG961, respectively. This mutation resulted in translation of a truncated enzyme protein, and the mutant protein showed no fructose-1,6- bisphosphatase activity in an overexpression experiment in Escherichia coli. However, this mutation is located in a region of the amino acid sequence which is not well conserved among mammals. A mutagenized clone was prepared from the normal clone. The extents of substitutions and deletions of the amino acid sequence were predicted to be less in the mutagenized protein than in the mutant protein. This mutagenized clone also expressed no fructose-1,6-bisphosphatase activity, although both of two normal clones from control monocytes and a control liver sample expressed an apparently normal level of fructose-1,6-bisphosphatase activity. Thus, this mutation is concluded to be responsible for fructose-1,6-bisphosphatase deficiency in this patient.

Amino Acid Sequence↗
PubMed1995

A clinical and histologic comparison between free temporoparietal and scapular fascial flaps.

It is universally accepted that the fascial flap is one of the best reconstructive strategies for contour and tendon-gliding function. In this study we compare the free temporoparietal fascial flap (n = 20) and the free scapular fascial flap (n = 6) mainly for these reconstructions and discuss their characteristics, including different clinical applications and histologic examination. Our histologic analysis reveals that the free temporoparietal fascial flap has a potential like a muscle flap; moreover, it is very thin. The free scapular fascial flap is very rich in adipose tissues to prevent adhesion between the flap and underlying tissues. Both flaps in our experience can bring satisfaction to the recipient site, but the donor site of the free temporoparietal fascial flap sometimes suffers from conspicuous widened scars in short-haired patients, and the scapular fascia has a tendency to be thicker in obese patients. Therefore, we recommend using the free temporoparietal fascial flap for women, who tend to have more fat and longer hair, and the free scapular fascial flap for men, who tend to be lean and shorten their side hair.

Adolescent↗
PubMed1994

[A cooperative study on the incidence of bacteriuria in patients with benign prostatic hypertrophy].

The incidence of bacteriuria in patients with benign prostatic hypertrophy was studied at 8 National Hospitals. Among 1,542 patients, urinary infection was the reason of visit in 63 patients (4.1%). After open and transurethral prostatectomy, one-third of patients developed bacteriuria (30 of 59 subcapsular enucleations, and 252 of 776 transurethral resections). When a catheter is placed without prophylactic antimicrobial, all patients developed bacteriuria within 10 days, and within 30 days even if they received antimicrobials. The incidence of bacteriuria increased with age.

Aged↗
PubMed1994

[Experimental study on the role of bacteria from urinary tract infections on the bladder carcinogenesis].

The role of bacteria isolated from patients with urinary tract infection (UTI) was studied with a view to the possibility that such bacteria are an etiological factor in the development of bladder cancer. The bacterial strains of Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Serratia marcescens, Staphylococcus epidermidis and Enterococcus faecalis, isolated from patients with UTI at the Kyushu University Hospital, were tested for their nitrate-reducing activity after 1 hr of incubation with sodium nitrate (3.57 mM) in a growth medium (pH 7.2) at 37 degrees C. Of 35 strains tested, 27 strains (77%) showed the ability to reduce nitrate to nitrite with yields ranging from 2 to 310 microM NO2-/hr/10(7) bacterial cells, but in 8 strains (23%) including all the 7 strains of E. faecalis no elevated activity (0.0-0.3 microM) could be detected. Various kinetic profiles were observed for the nitrate-reducing bacteria, at various rate ranging from rapidly to slowly, during 5 hr of incubation. The effect of nitrate-reducing bacteria on mutagen formation in the human urine was examined. The mutagenic activity of smokers' or non-smokers' urine incubated with or without bacteria for 72 hr at 37 degrees C was assayed by the Ames Salmonella/microsome test (using TA100 or TA98 with S9-mix). The mutagenic activity increased in urine incubated with the nitrate-reducing S. marcescens or P. aeruginosa, compared to controls which were incubated without bacteria. Potent mutagenic activity could be induced when the urine concentrate prepared from smokers' urine with an XAD-2 resin column was incubated with sodium nitrite (40 mM) at pH 3 for 4 hrs. The potent mutagenic activity observed here seems to be due to the class of direct-acting mutagen(s), because no metabolic activation was required. The mutagen formation at an optimal pH 4 proceeded rapidly during 4 hrs of incubation, but decreased thereafter. It was noted that even at a physiological pH 6 of human urine, a lower but significant level of mutagenic activity could still be detected. The mutagenic activity of individual urine concentrate from 14 male smokers and from 6 male non-smokers was assayed after 30 min of incubation with or without sodium nitrite (40 mM) at pH 6. Mutagenic activity increased in most of these urine concentrates incubated with sodium nitrite. The levels were variable between individuals with a 1.3- to 53-fold increase compared with the controls incubated without sodium nitrite.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1993

[Left ventricular function during hypoxia--II: Effects of intramyocardial pH].

We investigated the effects of intramyocardial acidosis on cardiac function during hypoxia in mongrel dogs (n = 50). Intramyocardial pH in subendocardium of left ventricle was measured continuously using a pH electrode. During hypoxia (PaO2 = 20 mmHg) caused by inhalation of low oxygen fraction, intramyocardial pH decreased significantly following initial enhancement. Intramyocardial pH correlated significantly with arterial pH, base excess, lactic acid (LA) levels, coronary venous PcO2, and coronary venous-arterial PcO2 difference. There were significant correlations between intramyocardial pH with maximum rate of rise of left ventricular pressure (LV dp/dt max), left ventricular end-diastolic pressure (LVEDP), LVEDP/LVP and the time constant of exponential isovolumic left ventricular pressure fall. High arterial LA levels tended to cease myocardial LA uptake and production, turning LA balance into zero. LV dp/dt max was low in such a condition. Myocardial LA production decreased intramyocardial pH, but LV dp/dt max was maintained at high levels of LA production. These observations suggest that myocardial LA production maintains left ventricular function with the increase of ATP by acceleration of anaerobic glycolysis. In conclusion, during hypoxia, intramyocardial acidosis was caused by the increase of arterial LA level, myocardial anaerobic glycolysis and ATP breakdown, and it worsened left ventricular contractile function and relaxation. Arterial LA levels can play a major part in intramyocardial acidosis, but the increase in myocardial LA production might be beneficial to left ventricular contractile function.

Animals↗
PubMed1992

Traumatic false aneurysm of finger tip. Case report.

A 13 year old girl presented with a false aneurysm of the tip of the left middle finger. This was treated by ligation of the branch of the digital artery and sac excision. The patient made an uneventful recovery. To our knowledge, only 10 such cases have been reported, and these were all proximal to the distal interphalangeal joint.

Adolescent↗
PubMed1992

Color selectivity of neurons in the inferior temporal cortex of the awake macaque monkey.

We tested the color selectivity of neurons in the inferior temporal (IT) cortex of two awake macaque monkeys. A color stimulus was presented at the center of the visual field while the animal performed a fixation task. The responses of single units to various colors were recorded and were plotted in a color space. The color space was based on the CIE (Commission Internationale de l'Eclairage) chromaticity diagram. Quantitative analysis of the color selectivity was performed using a standard set of colors that were evenly distributed in the color space. Sixty-five neurons recorded from eight guide tubes implanted in anterior part of IT cortex were tested quantitatively, and their color selectivity was statistically evaluated. Forty-six of them (71%) were classified as color selective. Color-selective cells responded to some colors but not to others, and we called the responsive region in the color space the "color field." The location and the size of a cell's color field were largely independent of the luminance of the stimulus. About 80% of the color-selective neurons had color fields consisting of a single responsive region that were restricted in some part of the color space, and the remaining cells had more than one responsive region within the color space. Preferred hues of the color-selective neurons differed from cell to cell. The population of cells together covered nearly all of the color space. There was a tendency for more color-selective cells to be less sensitive to white and desaturated cyans. Some of the cells with color fields that consisted of more than one responsive region were more sensitive to saturation of the stimulus than to its hue. Although previous electrophysiological studies in IT cortex emphasized the pattern selectivity of the neurons, our results suggest that color is an important factor in the role that IT cortex plays in the object recognition.

Analysis of Variance↗
PubMed1991

Epilepsy and driving: a survey of automobile accidents attributed to seizure.

From results of a survey of 72 epileptic car drivers who had a mean driving history of 8.6 years, 18 (25%) had experienced one or more automobile accidents ascribed to a seizure while driving, with the total number of accidents of the surveyed group amounting to 35. All the drivers were known to have partial epilepsy, 13 of them having temporal lobe epilepsy. The main characteristics of these 35 accidents were as follows: (1) Fifty-seven percent were caused by complex partial seizure without an aura in which consciousness was immediately impaired at onset, while about 10% were attributed to simple partial seizure in which the conscious state was not altered. No accident was caused by a first seizure; (2) Fifty-one percent occurred on an empty road with little pedestrian and/or vehicular traffic; (3) In about half the accidents, the driver's vehicle collided against an immovable object, and only 20% involved crashing into another car; (4) Most accidents caused damage to only the driver's car and/or mild physical injury; and (5) Fifty-four percent of the accidents were not reported to the police, and many that were reported were ascribed to driving while asleep, to careless driving or to similar behavior.

Accidents, Traffic↗