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Biomedical subjects

Y Kuwabara

Publications and source records attributed to Y Kuwabara.

At least 37 records · Page 2Linked to original sources
PubMed2001

Myocardial imaging with 123I-metaiodobenzylguanidine in essential hypertension and renovascular hypertension.

Iodine-123 metaiodobenzylguanidine (MIBG) myocardial imaging is considered to reflect cardiac sympathetic function. We performed myocardial MIBG scintigraphy and echocardiography in 27 patients with essential hypertension (EHT), 7 patients with renovascular hypertension (RVHT), and 8 normotensive subjects (NT) to investigate alterations in MIBG myocardial imaging in the presence of hypertension and left ventricular hypertrophy (LVH). EHT were divided into two groups based on LV wall thickness; EHT with LVH group (> or = 13 mm, n = 15) and EHT without LVH group (< 13 mm, n = 12). The delayed uptake of MIBG was decreased, and the washout rate of MIBG was greater in the EHT with LVH group than EHT without LVH group or NT group. The washout rate was correlated with LV mass and LV diastolic function (as assessed by mitral flow). In RVHT group, the MIBG washout rate increased even without LVH, compared with NT and EHT without LVH groups. In summary, the washout rate of MIBG increased in parallel with the development of LVH in EHT and increased independently of the LV mass in RVHT. Cardiac sympathetic function could be altered in hypertensive LVH and in renovascular hypertension.

3-Iodobenzylguanidine↗
PubMed2001

Detection of myocardial viability using rest-redistribution thallium-201 imaging in a stress 99Tcm-tetrofosmin/rest thallium-201 dual-isotope protocol.

This study investigated the utility of optional thallium-201 (201Tl) imaging for detecting myocardial viability in the stress 99Tcm-tetrofosmin/rest 201Tl dual-isotope protocol. Seventy-nine patients with old myocardial infarction and 25 patients with acute myocardial infarction underwent acquisition of three consecutive 201Tl images (early, intermediate and delayed) using the dual-isotope protocol. A polar map was created and defect scores (extent and severity) were determined by comparison with normal control data. Fluorodeoxyglucose positron emission tomography was also performed in 16 patients with old myocardial infarction. In patients with old infarction, the severity score decreased significantly from the early to the intermediate images, and decreased further on the delayed images. In patients with acute infarction, the score increased from the early to the intermediate images, but not on the delayed images. Regional uptake on the delayed images showed a better correlation with the fluorodeoxyglucose images than that on the early images. Redistribution on the delayed images was exclusively observed in the myocardial segments with less uptake than that estimated by fluorodeoxyglucose. In conclusion, addition of delayed 201Tl imaging to the dual-isotope protocol could improve the sensitivity for detecting myocardial viability.

Aged↗
PubMed2001

Cilnidipine more highly attenuates cold pressor stress-induced platelet activation in hypertension than does amlodipine.

The clinical significance of N-type calcium channel blockade has not been fully examined. We here compared the effects of the N-type calcium channel blockers cilnidipine and amlodipine on the sympathetic nervous system and platelet function in hypertension under resting and stressed conditions. Thirty-two patients with hypertension (58+/-9 years) received cilnidipine or amlodipine for 4 weeks in this crossover study. On day 28 of each treatment, plasma levels of epinephrine (EP), norepinephrine (NEP), and beta-thromboglobulin (BTG), and EC50 of ADP-induced platelet aggregation (ADPE50) were determined at rest and after a cold pressor test. On day 29, the group receiving cilnidipine was switched to amlodipine treatment, and vice versa. At rest, the blood pressure, heart rates, EP, NEP, ADPEC50, and BTG, were similar in both treatments. After the cold pressor test, increases in EP (35+/-17 to 44+/-25 pg/ml; p<0.05) and BTG (40+/-13 to 49+/-22 ng/ml; p<0.01) and a decrease in ADPEC50 (32+/-26 to 27+/-24 micromol; p<0.05) were observed in the amlodipine treatment, but not in the cilnidipine treatment. In addition, the increase in NEP was significantly greater (p<0.05) in the amlodipine (276+/-78 to 318+/-87 pg/ml; p<0.01) than in the cilnidipine treatment (273+/-88 to 291+/-100 pg/ml; p<0.05). Cilnidipine more highly attenuates the activation of platelet function in response to cold pressor stress than does amlodipine. Attenuated activation of the sympathetic nervous system via N-type calcium channel blockade may contribute to this phenomenon.

Amlodipine↗
PubMed2001

[A patient with probable dementia with Lewy bodies, who showed improvement of dementia and parkinsonism by the administratim of donepezil].

We present a 73-year-old man with probable dementia with Lewy bodies(DLB). At 65 years of age, he gradually developed bradykinesia, gait disturbance and mild amnesia. At 71 years of age, he noted resting tremor in bilateral hands, and amnesia and disorientation were exacerbated. He was diagnosed as having parkinsonism and took L-dopa/carbidopa at 100 mg/day. Since he developed hallucination and abnormal behavior 2 days after the initiation of the drug, he stopped taking L-dopa and was admitted to our hospital. A neurological examination on admission revealed moderate amnesia, disorientation, finger agnosia, constitutional apraxia, mask-like face, cogwheel rigidity, resting tremor in bilateral hands, and bradykinesia. Brain MRI showed mild brain atrophy, and single photon emission computerized tomography(SPECT) showed diffuse moderate hypoperfusion in bilateral cerebral cortex. As he had fluctuating cognitive dysfunction and parkinsonism, he was diagnosed to have probable DLB. As his dementia was exacerbated by trihexyphenidyl, an anti-cholinergic agent, at 2 mg/day, we treated him with donepezil, an anti-choline esterase agent, at 3-5 mg/day. His parkinsonism, including rigidity and bradykinesia, was markedly improved his dementia, consisting of amnesia and disorientation. Electroencephalography (EEG) improved in the organization of the dominant rhythm. The SPECT improved in the blood perfusion of the bilateral frontal lobe as well as cognitive function and parkinsonism were maintained by donepezil for 6 months after discharge. A therapeutic efficacy of donepezil for DLB has recently been reported. It is notable that donepezil was beneficial not only for cognitive dysfunction but also for parkinsonism in the present case with probable DLB.

Aged↗
PubMed2000

Effect of probucol on repeat revascularization rate after percutaneous transluminal coronary angioplasty (from the Probucol Angioplasty Restenosis Trial [PART]).

To address the issue of whether probucol reduces clinical events after percutaneous transluminal coronary angioplasty (PTCA), we surveyed clinical status at 1 year after PTCA of 101 patients who had entered the Probucol Restenosis Angioplasty Trial. Repeat angioplasty at index lesions were required in 5 patients in the probucol group and in 12 in the control group, suggesting that probucol administered beginning 4 weeks before PTCA reduces repeat revascularization rates for 1 year.

Angioplasty, Balloon, Coronary↗
PubMed2000

Prolonged effect of leukocytosis on reperfusion injury of rat intestine: real-time ATP change studied using (31)P MRS.

BACKGROUND: The intestine is one of the most sensitive tissues to ischemia and reperfusion (I/R). Polymorphonuclear neutrophils (PMN) may play an important role in ischemic injury. (31)P magnetic resonance spectroscopy (MRS) has been used to continuously monitor the energy metabolism of an animal in situ. We have applied MRS to study the effect of PMN on the I/R injury of rat intestine. MATERIAL AND METHODS: In a rat model of 30 min of intestinal ischemia and reperfusion, the number of PMNs was manipulated: group A, control; group B, leukopenia induced by cyclophosphamide; group C, leukocytosis induced by granulocyte colony-stimulating factor (G-CSF). MRS was employed to measure the level of real-time intestinal ATP and pH in vivo. RESULTS: In group A, ATP rapidly recovered on reperfusion to 61.0 +/- 11.0% of the preischemia level and maintained that level during reperfusion. The other two groups showed similar recovery of ATP at the initial phase of the reperfusion (<10 min). ATP in group B continued to recover, reaching 74.0 +/- 10.0% of the preischemia level. After the initial recovery, ATP in group C deteriorated reaching 46.0 +/- 4.4% of the preischemic level at 150 min of reperfusion. In group A and group B tissue pH decreased on ischemia and recovered on reperfusion in a similar manner. In group C, tissue pH was significantly lower than in other groups during I/R. CONCLUSION: Leukocytosis induced by G-CSF exerts a prolonged effect on ATP during I/R and leukocyte depletion helps protect against the I/R injury.

Adenosine Triphosphate↗
PubMed2000

Sex-related differences in the muscarinic acetylcholinergic receptor in the healthy human brain--a positron emission tomography study.

We evaluated the sex-related differences in the decline of the cerebral muscarinic acetylcholinergic receptor (mACh-R) due to aging by using 11C-N-methyl-4-piperidyl benzilate (11C-NMPB) and positron emission tomography (PET). The subjects consisted of 37 (20 males and 17 females) healthy volunteers. The 11C-NMPB uptake was evaluated by the ratio method (regional 11C-NMPB uptake/Cerebellar 11C-NMPB uptake; rNMPB ratio). The correlation between sex, aging, and the rNMPB ratio in normal aging was evaluated by a multiple regression analysis. The rNMPB ratio was higher in females than in males throughout the entire cerebral region (p < 0.01-p < 0.0001) and the rNMPB ratio might thus possibly decline with age more rapidly in females. Our study therefore revealed the existence of sex-related differences in the cerebral mACh-R.

Adult↗
PubMed2000

Biodistribution and breast tumor uptake of 16alpha-[18F]-fluoro-17beta-estradiol in rat.

To evaluate the usefulness of 16alpha-[18F]-fluoro-17beta-estradiol (FES) for the assessment of estrogen receptor (ER), we examined the tissue distribution and kinetics of FES in immature female Sprague-Dawley rats and then examined FES uptake in rat breast tumors induced by 7,12-dimethylbenz(a) anthracene (DMBA). The FES uptake by the uterus, an ER-rich tissue, was highly selective and it was 3.34 +/- 0.79%ID/g at 60 minutes and 1.57 +/- 0.57%ID/g at 120 minutes after injection. The FES uptakes in ER-negative tissues were 0.12 +/- 0.05%ID/g or less and 0.05 +/- 0.03%ID/g or less, respectively. Coadministration of unlabeled beta-estradiol showed marked depression of uterine FES uptake. The FES uptake by rat breast tumors was 0.14 +/- 0.06%ID/g at 60 min and 0.12 +/- 0.09%ID/g at 120 min. The FES uptake by rat breast tumors correlated with the ER concentration (r = 0.45, p < 0.05). In conclusion, these results suggest that the FES uptake by tissue is mainly ER mediated and FES is thus useful for detecting ER positive breast tumors.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2000

Effect of mental stress on left ventricular ejection fraction and its relationship to the severity of coronary artery disease.

To evaluate the relationship between the mental stress-induced decrease in left ventricular ejection fraction (LVEF) and the severity of exercise-induced ischaemia, 20 patients with stable coronary artery disease (CAD) underwent radionuclide ventriculography during mental stress testing and stress myocardial perfusion single-photon emission tomography (SPET). We also examined whether changes in haemodynamic and neurohormonal parameters are related to changes in LVEF during mental stress. The LVEF decreased from 54.8% +/- 17.7% to 49.8% +/- 16.2% with mental stress (P < 0.0005). Ten of the 20 patients (50.0%) had a > or = 5% decrease in LVEF The remaining ten patients had no or a <5% decrease in LVEF There was a significant correlation between the change in LVEF during mental stress and the size of the reversible defect on stress myocardial perfusion SPET (r = -0.80, P < 0.0005), with close regional correspondence (75% identical). This correlation was less strong in the 12 patients with a total defect score at rest of <10 (r = -0.69, P = 0.014) than in the eight patients with a total defect score at rest of > or = 10 (r = -0.94, P = 0.001). The changes in blood pressure and heart rate were not significantly correlated with the change in LVEF, but the percent change in adrenaline concentration correlated with the change in LVEE It is suggested that mental stress impairs systolic function by inducing transient myocardial ischaemia. The effect of neurohormonal responses during mental stress on LV systolic function may also be important in patients with CAD.

Aged↗
PubMed2000

Quantitative assessment of regional myocardial blood flow using oxygen-15-labelled water and positron emission tomography: a multicentre evaluation in Japan.

Recently, a method has been proposed for the quantitative measurement of regional myocardial blood flow (MBF) using oxygen-15-labelled water and positron emission tomography (PET). A multicentre project was organized with the intention of evaluating the accuracy of this method, particularly as a multicentre clinical investigative tool. Each of seven institutions performed PET studies on more than five normal volunteers following a specified protocol. The PET study included a transmission scan, a 15O-carbon monoxide static scan and a 15O-water dynamic scan, thereby yielding MBF values which should have been independent of the spatial resolution of the PET scanner employed. Fifty-three subjects (aged 20-63 years, mean+/-SD 36+/-12 years) were studied at rest, and 31 of these subjects were also studied after dipyridamole in five institutions. Inter-institution consistency and intra-subject variation in MBF values were then evaluated. MBF averaged for all subjects was 0.93+/-0.34 ml min(-1) g(-1) at rest and 3.40+/-1.73 ml min(-1) g(-1) after the administration of dipyridamole, and the flow reserve (defined as the ratio of the two MBF values) was 3.82+/-2.12; these values are consistent with previous reports. Resting MBF values were significantly correlated with the heart rate-blood pressure product (RPP) (y=0.31+6.56E-5x, P<0.010), and RPP was in resting MBF observed in all institutions was well explained by the age-dependent RPP. No significant difference was observed in resting MBF among the institutions. Except in one institution, no significant difference was seen in dipyridamole MBF or myocardial flow reserve. No significant difference was found among the myocardial segments. Regional variation was reasonably small in five institutions, but was not acceptable in two institutions, which was attributed to the scanner performance. These observations suggest that the 15O-water PET technique is useful for a multicentre clinical study if the PET scanner can provide time-activity data with good count statistics.

Coronary Circulation↗
PubMed2000

Significance of plasma thymosin alpha1 measurements in gastric cancer patients.

Thymosin alpha1 is a cleavage product of prothymosin alpha. Expression of prothymosin alpha increases during cell proliferation. Thymosin alpha1, measurable in plasma, may be an indicator of cell proliferation especially if a cancer is present. In this report we investigated the relation between the clinical behavior of gastric cancer and the plasma thymosin alpha1 level. Plasma thymosin alpha1 was measured in 52 gastric cancer patients using a newly developed radioimmunoassay. Twenty-one tumors and lymph nodes were examined for thymosin alpha1 using immunohistochemistry. The plasma thymosin alpha1 level was higher in gastric cancer patients than in normal volunteers; and it was higher in patients with lymph node involvement than in those with negative nodes. Immunohistochemical study of thymosin alpha1 showed positivity in 52% of gastric cancers and 100% of lymph node metastasis. We concluded that a high level of plasma thymosin alpha1 suggests aggressive behavior of a gastric cancer, such as lymph node involvement.

Biomarkers, Tumor↗
PubMed2000

Correlation between proton magnetic resonance spectroscopic lactate measurements and vascular reactivity in chronic occlusive cerebrovascular disease: a comparison with positron emission tomography.

The purpose of this study is to investigate the correlation between lactate levels and cerebral vascular reactivity (VR) in regions outside an area of chronic cerebral infarction. Multivoxel proton magnetic resonance spectroscopy ((1)H-MRS) and positron emission tomography (PET) were performed in 11 patients who suffered chronic cerebral infarction. Of these 11 patients, 4 were examined before and after bypass surgery. Two regions-of-interests (ROIs) were placed outside the area of chronic infarction. One ROI was placed within a control region on the contralateral side. A lactate peak area was obtained in all ROIs. An N-acetyl aspartate (NAA) peak area was obtained in the ROI within the control region. The ratio of the lactate peak area and NAA peak area (Lct/NAA) was calculated for normalization of the lactate level, and was found to be 0.13 +/- 0. 10 (range, 0 to 0.43). The VR was recorded at 13.3 +/- 20.7% (range, - 44.3 to 68.9%), utilizing PET and administering acetazolamide. A significant negative correlation was observed between the Lct/NAA ratio and VR (r = - 0.709, p < 0.0001). These results suggest that lactate levels and VR are closely related in regions outside areas of chronic cerebral infarction.

Adolescent↗
PubMed2000

Gelatinolytic activity of matrix metalloproteinase-2 and -9 in oesophageal carcinoma; a study using in situ zymography.

In this study, we investigated the activity of matrix metalloproteinase (MMP)-2 and -9 by gelatine zymography, immunostaining and in situ gelatine zymography in 30 oesophageal squamous-cell carcinomas. The gelatinolytic activity in situ was detected in all cases with different patterns of localisation. Significant gelatinolysis by stromal cells adjacent to tumour nests was found in 12 cases. Strong gelatinolytic activity appeared within the tumour nest itself in 13 cases. In the other 5 cases, both stromal cells and tumour cells showed the gelatinolytic activity. Gelatine zymography demonstrated a correlation between vascular invasion and activation of MMP-9. It also demonstrated a correlation between lymph node metastasis, lymphatic or vascular invasion and activation of MMP-2. These results suggest that MMPs play an important role in the invasion of oesophageal carcinoma.

Aged↗
PubMed2000

Placental pathology in systemic lupus erythematosus with antiphospholipid antibodies.

Systemic lupus erythematosus (SLE) is associated with a poor pregnancy outcome. Antiphospholipid antibodies (APL), which include lupus anticoagulant (LAC) and anticardiolipin antibodies (aCL), are frequently found in patients with SLE, and their presence has been associated with fetal loss. To examine placental pathologic features of SLE patients with APL, we performed a pathologic study on 47 placental tissue samples from 47 pregnant SLE patients with APL (15 patients; four LAC single-positive patients, seven aCL single-positive patients, four LAC and aCL double-positive patients) and without APL (32 LAC and aCL double-negative patients). The incidence of extensive infarction, decidual vasculopathy, decidual thrombosis and perivillous fibrinoid change, which have been thought to be characteristic lesions of APL placenta, was significantly higher in the LAC and aCL double-positive patients than in the patients without APL. Conversely, the above-mentioned lesions between the LAC or aCL single-positive patients and the APL negative patients did not differ significantly. Among the 15 patients with APL, two of the three patients with both decidual vasculopathy and thrombosis had extensive infarction associated with fetal death. Moreover, the patients having fetal death showed LAC and aCL double-positivity. In conclusion, this study indicated that the LAC and aCL double-positivity is an important factor for extensive infarction resulting from decidual vasculopathy and decidual thrombosis in the SLE placenta. Moreover, it was indicated that LAC and aCL double-positivity is an important risk factor for fetal death in the SLE patient.

Adult↗
PubMed2000

Long-term survivors after the resection of limited esophageal small cell carcinoma.

Patients with small cell carcinoma of the esophagus have a poor prognosis and have generally been treated by chemotherapy. However, all reported cases were at advanced stages. We need to establish an adequate treatment for patients with small cell carcinoma of the esophagus with invasion limited to the submucosal layer. In this paper, five cases of small cell carcinomas, which accounted for 2.8% of 180 surgically treated esophageal carcinomas, were reviewed for pathological findings, treatment, and outcome. Among three patients who had a small cell carcinoma of the esophagus with invasion limited to the submucosal layer, two patients survived for 7 and 9 years after surgery with no evidence of the disease. One of them was treated using surgery alone. Consequently, surgery may be considered as a possible choice of treatment for small cell carcinoma of the esophagus with invasion limited to the submucosa.

Adult↗
PubMed2000

Characterization of intracellular Ca(2+) increase in response to progesterone and cyclic nucleotides in mouse spermatozoa.

Rises in intracellular Ca(2+) concentration ([Ca(2+)](i)) caused by progesterone, an inducer of the acrosome reaction, or by cyclic nucleotides, possible second messengers, were investigated by Ca(2+) imaging of the head of individual mouse sperm. Progesterone induced a [Ca(2+)](i) rise in a dose-dependent manner (4-40 microM), primarily in the postacrosomal region. For 20-microM progesterone, Ca(2+) responses occurred in 42% of sperm, separated into two types: transient type (60% of responding cells; duration, 1-1.5 min; mean amplitude, 335 nM) and prolonged type (40%; >3 min; 730 nM). Prolonged responses required higher doses of progesterone, and their occurrence was enhanced significantly by preincubation for 2-4 h as compared with transient responses. 8-Bromo-cGMP (0.3-3 mM) induced a [Ca(2+)](i) rise more effectively than did 8-bromo-cAMP. For 1-mM 8-bromo-cGMP, 90% of cells exhibited transient Ca(2+) responses (approximately 1 min; 220 nM), independently of the preincubation time. In Ca(2+)-free medium, most sperm showed no Ca(2+) response to progesterone and 8-bromo-cGMP. Pimozide, a Ca(2+) channel blocker, completely blocked prolonged responses and partially inhibited transient responses. These results suggest that progesterone activates at least two distinct Ca(2+) influx pathways, with fast or slow inactivation kinetics, and some sperm show both types of response. A cyclic nucleotide-mediated process could participate in the progesterone-induced [Ca(2+)](i) rise.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed2000

New method to prevent bladder dysfunction after radical hysterectomy for uterine cervical cancer.

OBJECTIVE: The purpose was to improve the surgical procedures to prevent bladder dysfunction after radical hysterectomy. METHODS: Twelve patients with stage Ib cervical cancer underwent intraoperative electrical stimulation to identify the vesical branches of the pelvic nerves. Autonomic nerve localization in the vesicouterine ligament was examined in 10 patients immunohistochemically. According to the results of the above studies a new method to preserve the vesical branches was developed. Grades of postoperative bladder dysfunction were compared between new (n = 19) and conventional methods (n = 18). RESULTS: Electrical stimulation on the outer surface of the posterior sheath of the vesicouterine ligament caused the increase of intravesical pressure. S-100 protein localized also on this area. Postoperative compliance of the detrusor in cases with the new method demonstrated less decrement from preoperative values than in cases with the conventional method. The new method required significantly fewer days to achieve residual urine volumes less than 50 ml after surgery. CONCLUSIONS: The new method significantly reduces bladder dysfunction after radical hysterectomy.

Autonomic Pathways↗