Biomedical subjects

M Okada

Publications and source records attributed to M Okada.

At least 883 records · Page 49Linked to original sources

PubMed1994

Effects of naftidrofuryl oxalate on microsphere-induced changes in acetylcholine and amino acid content of rat brain regions.

Effects of naftidrofuryl oxalate (naftidrofuryl) on neurotransmitter, acetylcholine, and amino acid content of brain regions following microsphere-induced cerebral embolism were examined to elucidate its possible therapeutic effects on ischemic brain. Rats received 900 microspheres (48 microns in diameter) via the right internal carotid artery, followed by ligation of the right common carotid artery; and histological and biochemical alterations were examined on the 3rd, 5th, and 28th days after embolism. The embolism induced increases in triphenyltetrazolium chloride- (TTC)-unstained areas and decreases in acetylcholine, glutamate, aspartate, and gamma-aminobutyric acid (GABA) contents in the cerebral cortex, striatum, and hippocampus of the right hemisphere, suggesting that microsphere embolism causes severe damage to these brain regions. Hematoxylin-eosin staining of the right cortical sections after embolism showed degeneration and necrosis of nerve cells with chromatolytic nuclei and eosinophilic cytoplasm. Changes in neurotransmitters of the left hemisphere were relatively small. Treatment with naftidrofuryl of the embolized rats with stroke-like symptoms took place from postoperative day 1 to 28. Treatment resulted in a reduction in TTC-unstained areas, less morphological damage to cerebral cortex on the 3rd and 5th days, and an appreciable restoration of acetylcholine content of three brain regions of the right hemisphere throughout the experiment, but restoration of neurotransmitter amino acids was observed to a smaller degree. The results suggest that naftidrofuryl is capable of preventing the development of ischemia-induced, sustained damage to brain regions vulnerable to oxygen deficiency, particularly by improving impaired acetylcholine metabolism.

Acetylcholine↗

PubMed1994

Mitral valve replacement after atrioventricular canal repair in adults: report of three cases.

Three cases of adults who required a mitral valve replacement (MVR) following repair of an atrioventricular (AV) canal are presented herein. In adult patients with an AV canal, the deformity of the mitral valve is sometimes too advanced for adequate repair, and therefore, residual mitral regurgitation frequently causes intractable cardiac failure despite appropriate medical management. Thus, for adults with an AV canal associated with severe valvular deformities, MVR should be considered from the initial operation to obtain a significantly better outcome.

Adult↗

PubMed1994

Postoperative recurrence in patients with intestinal Behçet's disease.

PURPOSE: The postoperative course of intestinal Behçet's disease was studied in nine patients who had undergone a total of 15 operations due to intestinal ulcers. METHODS: These patients were followed up for an average of 6.0 years (range, 1 year, 3 months to 13 years, 10 months) after each operation and they were repeatedly examined by double-contrast radiography and/or colonofiberscopy. RESULTS: Recurrence of intestinal ulcers was observed in 12 (80 percent) of the 15 surgical cases. The incidence (50 percent) of postoperative recurrence in six cases in which intraoperative endoscopy revealed no abnormality in the retained intestine was lower than that (100 percent) in nine cases without this examination. Recurrent intestinal lesions in most cases were demonstrated as multiple aphthoid ulcers in the ileum near the ileocolectomy, or as one or two deep ulcers at the ileocolectomy site. The recurrent ulcers were successfully treated by various medical therapies, but the effectiveness of these therapies was only temporary. CONCLUSION: In the case of this disease, intraoperative endoscopy may be useful for preventing postoperative recurrence and periodic follow-up examination with radiography and endoscopy should be performed, even after surgery.

Adult↗

PubMed1994

Successful surgical treatment of a pseudoaneurysm after composite graft replacement of the aortic valve and ascending aorta: report of two cases.

Composite graft replacement of the ascending aorta and aortic valve has now become a safe surgical procedure; however, early and late complications still frequently occur. Anastomotic dehiscence after a composite graft replacement is one potentially lethal complication. We herein report two cases of a pseudoaneurysm caused by dehiscence of the right coronary anastomosis, and the proximal aortic anastomosis. A follow-up with an echocardiogram and computed tomography scan was found to be very useful and accurate. We thus successfully treated two cases of pseudoaneurysm using either Bentall's or Carbrol's procedures.

Adult↗

PubMed1994

The influence of intestinal flora on wound healing in mice.

The wound healing process was analyzed using male ICR germ-free (Gf) mice and their conventionalized (Cvz) counterparts to determine whether intestinal flora has any influence on the wound healing of a host. A longitudinal skin incision of about 35 mm was made in the dorsum of each mouse, and six interrupted sutures with 5-0 monofilament nylon thread laid for wound closure. Mice from both groups were killed on the 3rd, 7th, and 14th postoperative days, and the tensile strength of the healing wound and hydroxyproline (HP) concentration in the biologically active zone were measured as parameters of wound healing. The daily nitrogen balance and urinary creatinine excretion were also measured for 8 days. The Cvz mice showed greater tensile strength of the wound on the 3rd and 7th postoperative days, and a higher ratio of HP concentration, being wound tissue/control tissue, than their counterparts. The Cvz mice also thrived more prominently than the Gf mice, showing a positive nitrogen balance with limited urinary creatinine excretion. These results suggest the enhancing effect of normal intestinal flora on wound healing, probably through the beneficial nutritional effects supplied by the bacteria.

Animals↗

PubMed1994

Clinical course and long-term prognosis of Crohn's disease in Japan.

The long-term outcome of Crohn's disease was reviewed in 74 patients who had a history of more than 10 years (range 10.8-27.3) since disease onset. The observation period was between 4.3 and 18.5 years, the mean and SD being 10.6 +/- 3.1 years. The means and SD of age at onset and final observation were 21 +/- 7 and 37 +/- 8 years, respectively. Fifty-eight of the 74 patients had not undergone bowel resection at the time of diagnosis; of these 58, 31 (53.4%) had an operation for the disease during the follow-up period. Thus, of the 74 patients, 47 (63.5%) (these 31, plus the 16 who had undergone bowel resection at the time of diagnosis) had an operation at least once during a follow-up period of 10 years or more. The cumulative operation rates 5, 10, and 15 years after onset in the 74 and 58 patients above were 18.9%, 6.9%, and 40.8%, and 34.8%, 49.1%, and 46.0%, respectively. The corresponding figures 5 and 10 years after diagnosis in all 74 patients and the 58 patients were 32.3% and 28.6% and 47.3% and 46.3%, respectively. There were no significant differences in the incidence of operation rate in relation to anatomical involvement. Cumulative reoperation rates 1, 3, 5, and 10 years after the first operation in the 31 patients who were operated on during the follow-up period were 3.4%, 6.9%, 25.5%, and 51.7%, respectively. Three patients died, the causes of death in one being directly related to Crohn's disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1994

Intestinal and extraintestinal complications of Crohn's disease: predictors and cumulative probability of complications.

Of 238 patients with Crohn's disease seen at our clinics from April 1973 to August 1988, 203 patients were selected for this study, since they fulfilled the following criteria: they had been followed up for more than 6 months as outpatients or had been treated as inpatients for more than 1 month. They were studied to elucidate: (a) the different types and incidence of various complications, (b) the factors related to complications present at the time of diagnosis, (c) predictors of new complications arising after diagnosis, and (d) the cumulative incidence of complications occurring during the course of the disease from the times of onset and diagnosis. Of the intestinal complications, perianal fistula was most common (33%), followed by strictures with dilatations of the proximal bowel (21%), and internal fistula (14%). Of the extraintestinal complications, menstrual disturbance was the most common (18% of the female patients), followed by arthritis (10%), and aphthous stomatitis (10%). As for the factors influencing complications present at the time of diagnosis, the pattern of bowel involvement was significantly correlated with the presence of intestinal stricture, while the erythrocyte sedimentation rate was significantly correlated with the presence of perianal fistula. A significant predictor of new complications arising after diagnosis was the general well-being of patients at the time of diagnosis. Patients who, at diagnosis, already have complications such as stricture, abdominal abscess, internal or external fistula, massive hemorrhage, and free perforation or anal lesions are more likely to develop new complications in addition to those present at diagnosis, compared with patients without any complications at diagnosis (P = 0.055).

Adult↗

PubMed1994

Cervicothoracic vagal neurilemoma: report of a case.

We report herein the rare case of a 45-year-old man with a cervicomediastinal neurilemoma of the vagus nerve. The tumor was 160 x 40 x 35 mm in size and extended from the angle of the right mandible to the aortic arch. Despite this being the largest such tumor ever reported, the patient presented without any symptoms. Thus, although vagal neurilemoma is uncommon, it should nevertheless be included in the differential diagnosis of any asymptomatic mass along the vagus nerve. In the evaluation of such masses, magnetic resonance imaging can provide useful information regarding not only the location, but also the nature of the lesion.

Cranial Nerve Neoplasms↗

PubMed1994

Early diagnosis of acute rejection by pulmonary hemodynamics after single-lung transplantation.

The aim of this study was to facilitate the early diagnosis of acute rejection after single-lung transplantation based on pulmonary hemodynamic findings. A Doppler flowmeter was placed in the ascending aorta and the pulmonary artery of adult mongrel dogs after single-lung transplantation. The pulmonary hemodynamics of the lung graft were then evaluated during the early postoperative period and during subsequent rejection. Twenty dogs were divided into three groups. Group 1 consisted of 6 dogs that underwent autotransplantation of the left lung. Group 2 was made up of 6 dogs that underwent allotransplantation of the left lung without immunosuppressant therapy. Group 3 consisted of 8 dogs that underwent allotransplantation of the left lung and were treated with 10 mg/kg of cyclosporine and 4 mg/kg of azathioprine. Pulmonary hemodynamics and chest roentgenograms were studied for more than 2 weeks postoperatively. Open lung biopsy was performed in some dogs to obtain graft specimens for histologic examination. The left pulmonary artery flow rate (percentage of pulmonary graft blood flow to cardiac output) decreased slightly after operation in group 1, and decreased to 14.4% after 1 week and to zero on postoperative day 10 in group 2. The pulmonary vascular resistance of the grafts in group 2 also increased exponentially. In contrast, the left pulmonary artery flow rates decreased to 29.1% on the day after operation in group 3, but recovered to 38.5% on postoperative day 14. Within a mean of 3.7 days of immunosuppressant discontinuation, the left pulmonary artery flow rates decreased to less than 12.7%, with a marked increase in pulmonary resistance.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

PubMed1994

Imaging tumors of the minor salivary glands.

Magnetic resonance imaging evaluations of nine histopathologically confirmed minor salivary gland tumors were made retrospectively and compared with evaluations of images obtained by computed tomography. All tumors had low-to-intermediate T1 signal intensities and intermediate-to-high T2 signal intensities. Malignant tumors had an irregular margin in all but one case. Benign tumors invariably had well-defined margins. In terms of tumor margination, the magnetic resonance imaging findings correlated well with the histopathologic findings. Magnetic resonance imaging demonstrated the internal architecture of the minor salivary gland tumors multidirectionally and was superior to computed tomography in this respect and in the ability to locate the tumors.

Adenocarcinoma↗

PubMed1994

Detection of interleukin-6 and prostaglandin E2 in bronchoalveolar lavage fluids of pigs experimentally infected with Mycoplasma hyponeumoniae.

In this study, interleukin-6 (IL-6) and prostaglandin E2 (PGE2) were detected in the bronchoalveolar lavage fluids (BALF) from pigs experimentally infected with Mycoplasma hyopneumoniae. IL-6 was detected at 2 weeks post-inoculation (PI), and significantly increased levels of PGE2 were observed at 4 weeks PI. In the BALF collected from infected pigs at 4 weeks PI, the levels of IL-6 increased significantly in the pigs with pneumonic lesions. However, increased levels of PGE2 were observed in all the infected pigs.

Animals↗

PubMed1994

Anti-ubiquitin immunoreactivity associates with pyramidal cell death induced by intraventricular infusion of leupeptin in rat hippocampus.

Pathological studies on several neurodegenerative diseases including Alzheimer's disease have revealed common deposition of ubiquitin in many inclusion bodies. This implies a possible association of ubiquitin with neurodegeneration. To address this possibility, we examined histochemically the effect of intraventricular infusion of leupeptin, a thiol proteinase inhibitor, which is known to elevate anti-ubiquitin immunoreactivity in rat Purkinje cells. In the leupeptin-infused rat, an intense anti-ubiquitin immunoreactivity in the cytoplasm of neurons occurred not only in cerebellar Purkinje cells but also elsewhere in a wide area of the rat brain. The increase in the immunoreactivity was followed by a gradual depletion of pyramidal neurons in the hippocampal CA1 and CA3 subfields. The immunoreactive neurons disappeared concurrently. The number of anti-ubiquitin immunoreactive neurons was negatively correlated with that of surviving neurons when the duration of leupeptin infusion was varied. These results suggest that increased anti-ubiquitin immunoreactivity associates with neuronal death in leupeptin-treated rat brain.

Animals↗

PubMed1994

Sprouting of CA3 pyramidal neurons to the dentate gyrus in rat hippocampal organotypic cultures.

The understanding of the mechanisms of a functional synaptic plasticity in the hippocampus has been expanded greatly by the use of in vitro slice preparations. The question addressed in the present study was whether morphological plasticity observed in vivo can also be reproduced in hippocampal slices. In vivo, hippocampal commissural and association fibers are known to sprout and occupy synaptic sites vacated by deafferentation of the dentate gyrus (DG). In hippocampal slice preparations, the major input to the DG is eliminated, so that the DG is deafferented. Might intrinsic neurons sprout to the DG if the slice preparation is maintained for weeks? In this study hippocampal slices obtained from 6-day-old rats were cultured. Stimulation of the dentate stratum moleculare produced antidromic field potentials in the CA3 of the slices cultivated for more than 1 week. The antidromic response was not observed in CA1 pyramidal neurons. The CA3 to DG projection response was also observed in a CA3 mini-slice placed near a co-cultured whole hippocampal slice, when the DG in the latter was stimulated. Moreover, stimulation of the CA3 mini-slice induced synaptic responses in the DG of the whole-slice. The conclusion drawn is that deafferentation could induce axonal sprouting in a neuron-specific manner in hippocampal organotypic culture. This preparation would be potentially useful for the screening of chemical factors that influence sprouting of central neurons.

2-Amino-5-phosphonovalerate↗

PubMed1994

Possible involvement of central cholinergic system in ameliorating effects of indeloxazine, a cerebral activator, on disturbance of learning behavior in rats.

Effects of indeloxazine, a cerebral activator, on passive avoidance learning by disruption of cholinergic transmission were studied in rats. The shortened latency was prolonged when indeloxazine was administered before training in rats subjected to scopolamine-injection, ethylcholine aziridinium ion (AF64A)-treatment and nucleus basalis magnocellularis (NBM) lesion. Indeloxazine administered immediately after training also showed ameliorating effects on passive avoidance in NBM-lesioned rats. Indeloxazine increased extracellular acetylcholine concentration in the frontal cortex of rats. Indeloxazine possesses facilitatory effects on cerebral function in part due to activation of the central cholinergic system.

Acetylcholine↗

PubMed1994

Oligonucleotide probes for Bordetella bronchiseptica based on 16S ribosomal RNA sequences.

Bordetella bronchiseptica 16S ribosomal RNA (rRNA) gene was cloned and identified. On the basis of information from computer-assisted sequence comparison of the B. bronchiseptica 16S RRNA sequences with that of other bacterial species, we constructed B. bronchiseptica-specific oligonucleotide probes complementary to variable regions in the 16S rRNA molecule. Specificity of these 32P-labeled oligo-nucleotide probes was tested in a RNA/DNA hybridization with B. bronchiseptica strains and other bacterial strains. Probe BB4 was more specific than three other oligonucleotide probes. This probe BB4 was sensitive enough to be able to detect 10(4) bacterial cells.

Base Sequence↗

PubMed1994

Clinical implications of isolated T wave inversion in adults: electrocardiographic differentiation of the underlying causes of this phenomenon.

OBJECTIVES: This study aimed to assess the causes and clinical implications of isolated T wave inversion in adults and to evaluate electrocardiographic (ECG) differentiation of these causes. BACKGROUND: There are few previous reports on isolated T wave inversion in adults, which is a paradoxic observation in normal adults and in those with severe coronary artery disease. METHODS: We used echocardiography, stress thallium-201 scintigraphy and coronary angiography to determine the underlying causes and then used conventional electrocardiography and precordial ECG mapping to differentiate them. Eighty-six consecutive patients with isolated T wave inversion were classified as follows: group A included 23 asymptomatic patients; group B included 63 patients with chest pain. RESULTS: In group A, isolated T wave inversion was found as a normal variant in 20 patients and was due to hypertrophic cardiomyopathy in 3. In group B, the cause was hypertrophic cardiomyopathy in 3 patients, pericarditis in 2, coronary artery disease (lesions of the proximal left anterior descending coronary artery) in 39 and a normal variant in 19. The causes of isolated T wave inversion were difficult to determine from 12-lead ECG findings alone. However, when the inverted T wave region extended into the upper part of the precordium, precordial ECG mapping demonstrated excellent detection of coronary artery disease, with a sensitivity, specificity and overall accuracy of 88%, 93% and 91%, respectively. CONCLUSIONS: Isolated T wave inversion in asymptomatic adults is usually a normal variant. In patients with chest pain, isolated T wave inversions can develop in two different situations: a normal variant and severe coronary artery disease; these can be easily differentiated by precordial ECG mapping using conventional electrocardiography.

Adult↗

PubMed1994

Intestinal lymphangiectasia: value of double-contrast radiographic study.

Intestinal lymphangiectasia is a disorder presenting as enteric protein loss through the dilated lymphatics without mucosal ulceration. To determine the double-contrast radiographic features and to assess the significance of them, five patients with intestinal lymphangiectasia were examined using single- and double-contrast small intestinal studies. The double-contrast examinations demonstrated clearly the main radiographic findings of smooth nodular protrusions, thickening of the mucosal folds, with no evidence of mucosal ulceration. Compared with the single-contrast study, smooth nodular protrusions were seen more often and in more widespread segments, particularly in the duodenum, on double-contrast study. Thickening of the mucosal folds was revealed similarly by both methods. Double-contrast study appears to be worthwhile to demonstrate the characteristic radiographic findings of this disease.

Adolescent↗

PubMed1994

Effect of deoxyspergualin on vascular rejection in canine kidney transplantation.

Deoxyspergualin (DSG), an analogue of spergualin produced by Bacillus laterosporus, has a strong immunosuppressive effect in various transplantation models. In this study, we investigated the effect of DSG on vascular rejection in canine kidney transplantation. To enhance vascular rejection, donor-specific blood transfusion (DST) was carried out on days 28, 21 and 14 preceding kidney transplantation. After DST, the donor kidney was transplanted to the recipient iliac fossa. The recipient animals were divided into five groups: namely, Group 1 (n = 7), no treatment; Group 2 (n = 6), DST only; Group 3 (n = 5), DSG only (treated with DSG intravenously at 1.2 mg./kg./day for the first 3 days after transplantation, 1.0 mg./kg./day for the following 3 days and 0.8 mg./kg./day for the following 8 days); Group 4 (n = 6), DST and DSG treatment (same protocol as Group 3); and Group 5 (n = 5), DST and cyclosporine (CsA) (treated with CsA orally at 10 mg./kg./day for 14 days after transplantation). In Group 2, DST treatment significantly reduced kidney graft survival time (8.6 +/- 2.2 days) compared with Group 1 (14.1 +/- 5.5 days). Despite DST, DSG treatment (Group 4) significantly prolonged graft survival time (29.5 +/- 2.6 days), whereas treatment with CsA (Group 5) did not prolong survival time (14.1 +/- 5.5 days) (Group 4 versus 5, p < 0.01). The onset of rejection was significantly delayed in Group 4 (22.1 +/- 2.7 days) compared with Groups 2 (5.7 +/- 2.4 days) and 5 (13.0 +/- 5.7 days) (p < 0.01). In contrast, the interval between rejection onset and animal death was significantly reduced in Groups 2 (3.0 +/- 0.6 days) and 5 (2.4 +/- 1.0 days) compared with Group 4 (7.3 +/- 1.7 days) (p < 0.01). These findings suggest that DSG successfully prevented humoral-type (accelerated acute-type) rejections. Histologically, nonDST groups (Groups 1 and 3) showed minimum vascular rejection. In contrast, all recipients in Group 2 showed severe vascular rejection, as did 80% of CsA treated-animals (Group 5). Despite DST, however, 84% of DSG treated-animals (Group 4) showed minimal or mild vascular rejection and only 17% had severe rejection (Group 4 versus 5, p < 0.04). These data suggest that both clinically and histologically, DSG has more potent immunosuppressive effects against humoral and vascular rejection than CsA.

Animals↗