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Biomedical subjects

M Ohtani

Publications and source records attributed to M Ohtani.

At least 127 records · Page 7Linked to original sources
PubMed1994

A rapid method for detecting barbiturates in serum using EI-SIM.

A simple and rapid method for analysis of barbiturates in serum has been developed. In order to extract and clean barbiturates in serum, a separation column packed with Extrelut and Florisil was used, and the eluate was directly analyzed by means of electron impact selected ion monitoring (EI-SIM). Selected ions used were base peak ions of 10 barbituartes, and the internal standard used was allobarbital or secobarbital. The calibration curves were linear over the range 0.5-5 ng. Extraction of replicate serum samples containing 20 micrograms/1.5 ml and 5 micrograms/1.5 ml resulted in a recovery of 87.2-105.2% and 81.6-104.6%, respectively, with the exception of phenobarbital, which was 151.9% and 172.1%, respectively. Secobarbital was also analyzed in the serum of 13 patients who had been given secobarbital intravenously. In 3 out of 10 cases, secobarbital levels greater than 1 micrograms/ml were detected more than 72 h after administration. This method seems to have possibilities for clinical use.

Adult↗
PubMed1994

Cardiac hemangiopericytoma growing in the left atrium.

A 49-year-old woman was seen because of exertional dyspnea. Two-dimensional echocardiography revealed the presence of a large mass in the left atrium. An urgent operation was performed because the tumor suddenly stuck in the mitral orifice. The lesion, which occupied the entire left atrium, was resected during cardiopulmonary bypass. Histologic analysis revealed malignant hemangiopericytoma.

Female↗
PubMed1994

Visual pigments in the pineal complex of the Japanese quail, Japanese grass lizard and bullfrog: immunocytochemistry and HPLC analysis.

We investigated localization of visual pigments in the pineal complex of Japanese quail, Japanese grass lizards and bullfrogs immunocytochemically by use of the antiserum against bovine rhodopsin (Rh-As) and monoclonal antibodies against chicken iodopsin (Io-mAb). We also analyzed retinoids, chromophores of visual pigments, by a high performance liquid chromatography (HPLC). The outer segments and cell membranes of some photoreceptor cells in the pineal organ of the Japanese quail exhibited immunoreactivity to Rh-As, but there are also many immunonegative cells. The number of immunoreactive cells among individuals varied. Immunoreactivity to Io-mAb was weak or did not exist. The HPLC analysis revealed peaks of 11-cis and all-trans isomers of retinal in the oxime extracts of the pineal organ of Japanese quail and chickens. In the pineal of Japanese grass lizards, the outer segments of some cells were immunopositive to Io-mAb, but there were no cells immunoreactive to Rh-As. The parietal eye exhibited a well-developed lens and photoreceptor cells, but the outer segments of photoreceptor cells were immunonegative to both Rh-As and Io-mAb. In bullfrogs, three types of cells were identified in both the pineal and frontal organ; (1) immunopositive to Rh-As, (2) immunopositive to Io-mAb and (3) immunonegative to either of the antibodies. In the pineal organ of bullfrogs, 11-cis and all-trans retinal and 11-cis 3-dehydroretinal were detected, and 11-cis and all-trans retinal were also detected in the frontal organ. We detected 11-cis and all-trans retinal in the ventral part of diencephalon including the hypothalamus. Thus, the chromophore is the same between the retinal and pineal visual pigments, but the expression of opsins is different between the retina and pineal complex, which probably reflects the different function of each organ.

Animals↗
PubMed1994

Cholinergic agonists increase intracellular calcium concentration in frog vestibular hair cells.

Acetylcholine (ACh) is usually considered to be the neurotransmitter of the efferent vestibular system. The nature and the localization of cholinergic receptors have been investigated on frog isolated vestibular hair cells (VHCs), by measuring variations of intracellular calcium concentration ([Ca2+]i), using calcium sensitive dye fura-2. Focal iontophoretic ACh (1 M, 300 nA.40 ms) application induced a rapid increase in [Ca2+]i, reaching a peak in 20 s and representing about 5-fold the resting level (from 61 +/- 6 to 320 +/- 26 nM). Applications of muscarinic agonists as methacholine and carbachol induced weaker calcium responses (from 78 +/- 25 to 238 +/- 53 nM) than the one obtained with ACh applications. These muscarinic agonists were efficient only in precise zones. Desensitization of muscarinic receptors to successive stimulations was significant. Perfusion of nicotine or 1,1-dimethyl-4-phenyl-piperazinium (DMPP), a nicotinic agonist, induced an increase in [Ca2+]i only in some cells (4/28 with DMPP). These results indicated the presence of cholinergic receptors on frog VHCs: muscarinic receptors were more responsive than nicotinic receptors. Presence of muscarinic and nicotinic receptors in the membrane of VHCs could indicate different modulations of VHCs activity mediated by [Ca2+]i and involving an efferent control which represents a central regulation of the vestibular afferent message.

Acetylcholine↗
PubMed1994

A new tumor marker for bladder cancer.

Biochemical assay and immunohistochemical staining of neutral endopeptidase were performed on bladder cancer cells. In superficial bladder cancer the enzyme activity and immunohistochemical intensity of staining were high, while invasive bladder cancer showed only a low level of activity. This finding suggests that neutral endopeptidase is expressed at a certain stage of cell differentiation, during the neoplastic process in the bladder. Gene expression is assumed to be closely correlated with this mechanism. From the results of this study neutral endopeptidase will serve as a new tumor marker for bladder cancer as well as acute lymphatic leukemia.

Biomarkers, Tumor↗
PubMed1994

Preliminary results of bladder-preserving therapy with definitive radiotherapy and intraarterial infusion of chemotherapy.

PURPOSE: For management of muscle-invading bladder cancer (clinical stages T2 to T4), combined treatment of definitive radiotherapy (RT) and intraarterial (IA) administration of chemotherapy was carried out for local cure and bladder preservation. METHODS AND MATERIALS: Between 1987 and 1990, a pilot study (Protocol-1) was initially conducted in 16 patients to investigate the efficacy of chemoradiotherapy where RT was combined with TURB and continuous IA infusion of cisplatin. We then performed a regimen of possible bladder-preservation treatment (Protocol-2) in which 19 patients were treated with combination of TURB, full-dose RT and one-shot IA infusion of cisplatin and methotrexate. In RT small pelvis irradiation was performed with x-rays followed by proton beam boost irradiation to the original tumor site. RESULTS: Among patients treated on Protocol-1, a tumor-free bladder was observed in 50% (2/4) after 50-76 Gy but only 8% (1/14) after 30-40 Gy. In this regimen, planned cystectomy was performed in 10 patients and 13 patients (81%) are alive. Among 19 patients treated on Protocol-2, 17 patients (89%) are alive and 13 patients (68%) retained intact bladders without any recurrence. There were 3 cystectomies performed because of persistent tumors. Using a conformal mode of proton beam irradiation, a total dose of 60-80 Gy was safely administered with acceptable morbidities. CONCLUSION: In the light of good complete response and survival rates achieved in the patients treated on Protocol-2, the combined treatment of definitive RT and IA administration of chemotherapy is considered as an effective bladder-preserving strategy.

Aged↗
PubMed1994

[Surgical treatment of descending thoracic aortic aneurysm with simple aortic cross-clamping versus left heart bypass using centrifugal pump].

Surgical treatment has been employed in 52 patients (pts) with descending thoracic aortic aneurysm (DS-TAA). Based on the adjuncts during aneurysmal repair, the series is divided into 2 groups; simple aortic cross-clamping was utilized to manage the lesion in group SC (n = 42), while left heart bypass using a centrifugal pump was employed during the period of aortic occlusion in LHB group (n = 10). Of these 52 pts, 4 died in hospital (group SC:2, group LHB:2). The most common complication was the respiratory failure following the renal failure. No paraplegia occurred in both groups. Biochemistric measurements of alanine aminotransferase, creatinine (CRN) and amylase (AMY) showed no difference between group SC and group LHB. In pts of SC group with normal renal function, post-operative maximum (post Max) CRN during the first month had a logarithmic correlation with total aortic cross-clamp time (TAXT). The post Max CRN of LHB group with normal renal function remained less than 3.0 mg/dl even in the case with TAXT over 60 minutes. There is also a linear correlation of post Max AMY in pts of SC group. Late survival at 4 years, including hospital death, were 83% in SC group and 63% in LHB group. We conclude that DS-TAA cases with TAXT of less than 30 min with good distal organ function can be managed with simple aortic cross-clamping; otherwise usage of LHB was recommended to support distal circulation.

Adult↗
PubMed1994

[Respiratory and circulatory changes under high intra-abdominal pressure].

In order to determine the safety limit of abdominal pressure, the influence of abdominal pressure on the respiratory and circulatory systems was examined by changing it from 0 to 50 mmHg in dogs with carbon dioxide insufflation. Total peripheral resistance increased slightly after pneumoperitoneum but increased rapidly when 30 mmHg was exceeded. Cardiac output tended to decrease with an abdominal pressure above 30 mmHg. Static compliance decreased in response to the abdominal pressure up to 20 mmHg but the decrease became rather gentle when 30 mmHg was exceeded. Peak inspiratory airway pressure increased in response to the increased abdominal pressure up to 30 mmHg followed by small fluctuations thereafter. These evidences indicate that an abdominal pressure below 15 mmHg is desirable for performing a peritoneoscopic operation safely because the biocompensatory system may be impaired when the pressure exceeds 30 mmHg.

Abdomen↗
PubMed1993

Expression of antitumor response. Role of attachment and viability of bacillus Calmette-Guérin to bladder cancer cells.

BACKGROUND: Antitumor effects of Bacillus Calmette-Guérin (BCG) against superficial urinary bladder cancer is known to be strong when BCG is directly infused into the bladder cavity. For expression of that effect, attachment of BCG to tumor cells is reported to be essential as the first step. Our study was conducted to elucidate the significance of attachment of BCG to tumor cells in inducing the antitumor effect. METHODS: BCG, Tokyo 172 strain, in the form of live bacilli, lyophilized bacilli, or autoclaved bacilli was co-cultured with MBT-2, mouse-origin transitional cell cancer cells. Various preparations of BCG were mixed with MBT-2 cells and transplanted to male C3H/He mice to see tumor growth-inhibiting effect. RESULTS: Both live and lyophilized BCG attached strongly to MBT-2 cells. The maximal attachment to the cells with live BCG occurred 24 hours earlier than with lyophilized BCG. When BCG was autoclaved, it lost the ability to attach to the cells. Lyophilized or autoclaved BCG exerted a marked tumor growth-inhibiting effects. This effect was equal to the Tokyo 172 strain and the Armand Frappier Canada strain. Histologically, a high degree of infiltration by macrophages was seen. CONCLUSIONS: The results indicated that coexistence of BCG, even as killed by autoclaving, with tumor cells activates local immunity. Accordingly, the significance of the attachment of BCG to tumor cells in intravesical infusion therapy is surmised to lie in the fact that it results in retention of the BCG at the reaction site. This may provide a clue on how to approach future development of safer and more stable BCG-derived antitumor drugs.

Animals↗
PubMed1993

[Image-transmission of radiotherapy planning using 64kbps-ISDN videophone].

We carried out the image-transmission using the 64kbps-ISDN and two terminals of the videophone installed in Osaka Teishin Hospital and Department of Radiation Oncology, Biomedical Research Center, Osaka University Medical School. The frame speeds (sec./frame) of the videophone are 1.2 for standard resolution with 320 x 200 matrix and 5.0 for high resolution with 640 x 400 matrix. Although the image with 640 x 400 matrix is not enough for the radiation diagnosis such as the chest radiogram, the image is useful for the radiation therapy planning. This system is easy to operate, and will be widely distributed in near future.

Computer Communication Networks↗
PubMed1993

The function of the hypothalamo-pituitary axis in brain dead patients.

In order to find out the function of the hypothalamo-pituitary axis in brain dead patients, pituitary and hypothalamic hormone concentrations were measured and several anterior pituitary releasing tests were carried out in 39 brain dead patients. In addition, cerebral blood flow measurements were simultaneously performed. In almost all cases, the blood concentration of pituitary and hypothalamic hormones were above the sensitivity of the assay. Anterior pituitary releasing tests indicated that efficient functions of the hypothalamus were severely suppressed, while the normal secretory mechanism of the anterior pituitary was partially preserved in brain dead patients. Histological changes of hypothalamic neurons varied from barely detectable ghost cells to nearly normal cells even in the same case. Although, the remaining circulation seemed not to be sufficient enough to maintain integrated hypothalamo-pituitary function, as shown by the examinations of cerebral blood flow, the presence of hypothalamic hormones in the systemic circulation suggests that these hormones were released and carried from the hypothalamus by minimal flow which is preserved even after the diagnosis of brain death.

Adolescent↗
PubMed1993

Hyperaemia prior to acute cerebral swelling in severe head injuries: the role of transcranial Doppler monitoring.

Acute cerebrovascular congestion after a closed head injury is significantly related to intracranial hypertension. As an indirect method of cerebral blood flow measurement; transcranial doppler sonography (TCD) provides a rapid and noninvasive assessment of cerebral haemodynamics, including hyperaemic conditions. TCD examinations was serially performed in 35 patients with severe head injury with intact cerebral circulation; i.e. the mean flow velocity (MFV) patterns of the middle cerebral artery (MCA) did not show signs of cerebral circulatory arrest such as systolic spike, to and fro, or no flow. The results showed that the MFV of the MCAs and ipsilateral extracranial internal carotid arteries (ICAs) in 9 of these patients increased sharply and pulsatility index (PI) decreased during 48-96 hours after the injury. This was soon followed by patterns of high intracranial resistance, consistent with elevated intracranial pressure (ICP) in monitored patients and acute brain swelling on repeated computed tomographic (CT) scans. The correlation between increased MFVs, decreased PIs, and cerebral haemodynamic changes leading to acute brain swelling is discussed. The number of patients who ended with severe disability, vegetative state, or death was 66% in this group of 9 patients, compared to only 34% for the 35 patients overall with severe head injury. Though the morbidity and mortality rates largely depend on the primary injury, the presence of acute cerebral swelling aggravate the grave course in these patients. And the ability of TCD to monitor the hyperaemic state prior to oedema should lead us to adjust the therapy in order to minimize the secondary insult related to intracranial hypertension.

Adult↗
PubMed1993

Effects of efferent neurotransmitters on intracellular Ca2+ concentration in vestibular hair cells of the guinea pig.

The effects of putative efferent neurotransmitters on intracellular Ca2+ concentration ([Ca2+]i) in isolated vestibular hair cells (VHCs) of the guinea pig were determined using the Ca2+ sensitive dye Fura-2 and digital imaging microscopy. In the presence of 1 mM acetylcholine (ACh) there was a gradual increase in [Ca2+]i. In the presence of 10 microM ATP there was a rapid rise in [Ca2+]i. Thus, both ACh and ATP seem to be efferent neurotransmitters in VHCs of the guinea pig. When 100 microM Gamma-aminobutyric acid (GABA) was added there was a rapid increase in [Ca2+]i; thus GABA also seems to be an efferent neurotransmitter in VHCs. With the independent addition of 10 microM calcitonin gene-related peptide and 10 microM M- and L-enkephalin there were no significant increase in [Ca2+]i. We presume that these neuropeptides were functioning as efferent neuromodulators rather than as neurotransmitters.

Acetylcholine↗
PubMed1993

Thermal influence on intracellular calcium concentration in vestibular hair cells isolated from the guinea pig. A preliminary report.

Caloric responses to intracellular calcium homeostasis of vestibular hair cells isolated from the guinea pig were examined. An increase in intracellular free calcium ion concentration ([Ca2+]i) in the isolated cells was observed by direct heat stimulation. The cells, dissociated enzymatically or mechanically, were stimulated by perfusion of solution, in the temperature range of 2.2-5.2 degrees C. The [Ca2+]i was analysed using a digital imaging microscope and the Ca2+ sensitive dye, Fura-2. There was an increase in [Ca2+]i in both Types I and II vestibular hair cells with this heat stimulation. The direct thermal influence on vestibular sensory cells is discussed in relation to mechanisms involved in caloric nystagmus.

Animals↗
PubMed1993

[Histopathological comparison of stage A prostatic adenocarcinoma in Japan and the United States].

Histopathological characteristics of stage A prostatic adenocarcinoma from Japan (137 cases) and the United States (51 cases) were comparatively evaluated by retrospective analysis. All cases were examined by one referee pathologist (MH) using classification based on Japanese General Rules for Prostatic Cancer (JGRPC), nuclear grading by Mostofi-WHO system and Gleason grading. The incidences of the cases with well differentiated, low nuclear anaplasia and Gleason grade 1 or 2 on primary and secondary grades as well as histologic score 2-4 were much more higher in the cases from Japan as compared with those from the US. In the cases from the US proportion of the cases with moderately differentiated adenocarcinoma and grade 2 nuclear anaplasia exceeded those with well differentiated and grade 1 anaplasia. Adenocarcinomas with Gleason grade 3 in primary and secondary grade and 6-8 of histologic score were also more frequently observed in the cases from the US. No different distribution of each histologic grade could be obtained among the Japanese cases classified stage A2 and entire cases from the US. These results suggest that much more stage A adenocarcinoma in the US might fall into A2 if strict criteria was applied for subcalssification of stage A, which may reflected in the remarkable difference in the incidence of clinical prostatic carcinoma.

Adenocarcinoma↗
PubMed1993

[192Ir brachytherapy].

Modern high technology has recently brought a precision treatment modality in the field of brachytherapy for cancer patients. Ir-192 manual afterloading (hair pin technique of Ir-192 wire) replaced the technique utilizing Ra-226 needles at our department in 1973. In May 1991, microSelectron-HDR (Ir-192 micro-source of 370 GBq) was installed in Osaka University Hospital. Preliminary analysis of phase I/II study resulted in no significant differences between the incidence of an acute mucosal reaction as well as early tumor response after high and low dose rate interstitial brachytherapy for oral cancer. Since April 1992, a phase III study has been under way to completely eliminate the problem of hospital personnel exposure to radiation in the field of brachytherapy. The introduction of remote after-loading of Ir-192 micro-source has resulted in improvements in elderly patient care during the interstitial brachytherapy for malignancies. The indications for HDR brachytherapy have been expanded, and new technology was developed to improve the local cure of the disease, such as linked double button technique for oral cancer, template interstitial brachytherapy for perineal cancer, and postoperative brachytherapy using intraoperative flexible catheter placement for locally unresectable disease or microscopically residual disease. Through these meticulous efforts, HDR interstitial brachytherapy will soon become a satisfactory substitute for traditional LDR interstitial brachytherapy.

Adult↗
PubMed1993

Introduction of a "safety zone" for the safety of laparoscopic cholecystectomy.

Anatomic variations of the biliary tract were found in 18 cases of 600 patients (3.0%) undergoing laparoscopic cholecystectomy. All bile duct anomalies were confirmed preoperatively by endoscopic retrograde cholangiography. In every case, the cystic duct and cystic artery were exposed in a "safety zone" near the gallbladder neck in Calot's triangle. Laparoscopic cholecystectomy was successfully performed on all 18 cases. Intraoperative cholangiography clearly demonstrated the anatomic variations in all cases, unequivocally identified the cystic duct, and confirmed the absence of bile duct injury. Preoperative endoscopic retrograde cholangiography and intraoperative cholangiography, which have been performed routinely in all patients, improve the safety of laparoscopic cholecystectomy. Moreover, the observance of the essential rule of "keep operating in the safety zone" protects against inadvertent complications, especially against bile duct injury during laparoscopic cholecystectomy. Laparoscopic cholecystectomy was thus successfully performed on all 600 cases in the present series, except for three cases, which were converted to open surgery (conversion rates, 0.5%), because of pin-hole bleeding on the portal vein in our first case of 600, and severe adhesion in two (46th and 302nd) cases.

Bile Ducts↗