Biomedical subjects
Publications and source records attributed to R Suzuki.
We demonstrated normal CT anatomy of the brain stem and adjacent structures using thin slice CT cisternography. Reducing the streak artifact caused by bony structures, thin slice CT cisternography can visualize the detailed features of the brain stem and its pathological changes. In addition, reconstructed images are also useful in diagnosis.
To investigate the perifocal abnormal signal intensity area in MRI in meningiomas, we have analysed MRI in 10 cases among 73 meningiomas which were diagnosed by X-ray CT and verified by operation and pathology. The MRI scanners used in this study were Siemens Magnetom and Toshiba MRT 15A. Ten meningiomas diagnosed by MRI were as follows; one free convexity, one pyramidal, three falx and parasagittal, one sphenoid ridge, one olfactory groove, one cerebellopontine angle, two ventricular meningiomas. Perifocal abnormal signal intensity area was diagnosed as vasogenic edema in 4 cases. This area was shown as high signal intensity in T2-weighted MRI and was confined to the white matter. In proton density-weighted MRI, it was shown as high signal intensity and usually clearly distinguished from rather iso- or hypointensity tumor area. In T1-weighted MRI, this area was shown as slightly low signal intensity, which could be readily differentiated from the remarkably low intensity ventricular CSF. In one case a thin semi-lunar abnormal intensity area bordering the tumor was verified in MRI, but no abnormal area was shown in CT. In the remaining 6 cases, namely one free convexity, one pyramidal and two ventricular meningiomas, one cerebello-pontine and one sphenoid ridge meningioma, in which CSF abutted the tumor, abnormal signal intensity area was diagnosed as entrapped CSF space. The perifocal abnormal signal intensity area in MRI should be regarded as vasogenic edema or entrapped CSF space, and these two should be differentiated by the signal intensity, the distribution of the area and CT-cisternography.(ABSTRACT TRUNCATED AT 250 WORDS)
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The correlation between the effectiveness of radiation therapy and the histology of soft tissue sarcomas was investigated. Of 31 cases with a soft tissue sarcoma of an extremity treated by conservative surgery and postoperative radiation of 3,000-6,000 cGy, local recurrence occurred in 12; 5 out of 7 synovial sarcomas, 4 of 9 MFH, one of 8 liposarcomas, none of 4 rhabdomyosarcomas and 2 of 3 others. As for the histological subtyping, the 31 soft tissue sarcomas were divided into spindle cell, pleomorphic cell, myxoid and round cell type, and recurrence rates were 75%, 33.3%, 16.7% and 0%, respectively. From the remarkable difference in recurrence rate, it was suggested that round cell and myxoid type of soft tissue sarcomas showed a high radiosensitivity compared to the spindle cell type with low sensitivity. Clarifying the degree of radiosensitivity is helpful in deciding on the management of limb salvage in soft tissue sarcomas of an extremity.
We compared the effects of acetylcholine and carbachol on iris sphincters. The muscle strips (mostly bovine tissues) were isolated and incubated in a 0.2ml organ bath. Results revealed an approximately ten-thousandfold difference in potency between carbachol and acetylcholine, in the bovine iris. Acetylcholine and/or endogenous chemical agents were spontaneously released from bovine tissue. Acetylcholinesterase activity in this tissue strongly inhibited the acetylcholine action, in order to protect the nerve terminals from random depolarization due to the released acetylcholine. Among several species (bovine, rabbit, hamster), Ach action was the least in the bovine iris sphincter muscle.
Responses of bovine iris sphincter and dilator evoked by electrical stimulation were recorded in vitro. In order to examine the time course of the iris sphincter and the dilator, the two muscle strips were investigated under the same conditions; i.e., the iris sphincter and the dilator were immersed in parallel in a 0.5 ml organ bath, thus perfused with the same fluid and stimulated by the same electrical pulses. Remarkable difference was found in the time courses between the iris sphincter and the dilator, and this difference was discussed in relation to pupil movement.
Effects of prostaglandins and/or indomethacin on the cooling induced contraction of the bovine iris sphincter muscle were studied in vitro. Cooling of the bathing solution contracted the bovine iris sphincter and the muscle became sensitive to carbachol. Lowering the temperature elevated the muscle tone, while with pretreatment of indomethacin, the elevation was markedly inhibited. Further application of prostaglandins (PGs) such as 10(-8)-3 X 10(-8) M PGE2 reproduced the response induced by low temperature. Effects of cimetidine, methysergide and naloxone were also studied. Whether PGs are exogenously applied or endogenously produced, PGs are responsible for the induction of such responses.
A 1-year-old baby boy with discrete subaortic stenosis in Kelly type I had coexisting echocardiographic evidence for probably indicating the presence of hypertrophic cardiomyopathy in early stage. At surgery, a discrete subaortic "fibrous membrane" was excised: although the thickening of upper ventricular septum was not thought to be so prominent, the prognosis is related to the natural history of hypertrophied muscle despite successful surgical removal of the subaortic diaphragm.
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We have studied the mechanism of L-glutamate/L-aspartate transport in a fermentative oral bacterium of Streptococcus mutans (strain Ingbritt). The transport rate stays virtually constant throughout the pH range 5.5-8.5 and followed Michaelis-Menten type kinetics. At high pH values from 7 to 8.5, transport was essentially insensitive to N,N'-dicyclohexyl-carbodiimide (DCCD), an inhibitor of ATPase, and to carbonyl cyanide-p-trifluoromethoxyphenyl-hydrazone (FCCP), an ionophore dissipating proton motive force indicating that S. mutans transports glutamate by a primary transport system at the expense of ATP or an alternative energized metabolite. At lower external pH (7-5.5), DCCD (100 microM) or FCCP (10 microM) significantly inhibited L-glutamate transport while the intracellular ATP level was hardly affected, indicating that the activity of the primary transport system was decreased at lower intracellular pH. The glutamate transport was stimulated in the presence of potassium ion at an external pH of 6. The stimulation can be explained partly by the regulation of intracellular pH with concomitant potassium ion movement.
Spleen mononuclear cells of C3H/HeN mice were cultivated with mitomycin C-treated tumor cells, X5563, MH134, MM48, MM46, and FM3A/R, all of which were of syngeneic origin, in a medium containing normal syngeneic mouse serum but not FCS. There was a proliferative response to X5563, MH134, and MM48, but not to the two other tumor cells, MM46 and FM3A/R. The responder spleen cells were found to be nonadherent cells with a phenotype of Thy-1-L3T4-Lyt2-Ig-Macl-, which were neither mature T and B cells nor mature macrophage/granulocytes. It was also found that the proliferation of these nonadherent no-marker cells was mediated by tumor cell-derived soluble factors but not by direct stimulation with tumor cells. The responsible factor was a molecule(s) with a Mr of 23 to 25 kDa, which had a CSF activity inducing granulocyte (G)-, macrophage (M)- and G + M-colonies in the bone marrow cells. Neutralization tests of this factor-induced proliferation of spleen cells revealed that a major part of the factor may be GM-CSF or a molecule closely related to it. Incubation of spleen mononuclear cells with these GM-CSF-like tumor cell factors resulted in induction of myeloblastic/promyelocytic cells with a phenotype of Mac-1+2+Ia+ Thy-1-L3T4-Lyt2-Ig- in the spleen cell cultures, which could suppress mitogenic responses of the spleen cells to T and B cell mitogens. GM-CSF-like activity could also be detected in the serum of mice bearing X5563, MH134, and MM48, but not in those bearing MM46 and FM3A/R. Subcutaneous inoculation of C3H/HeN mice with these X5563, MH134, and MM48 tumor cells generated massive metastasis in the lung and lymph nodes, whereas MM46 and FM3A/R produced no macroscopic tumor cell metastasis. These results strongly suggest the possibility that in some tumor cell-host systems, a GM-CSF-like factor(s) produced constitutively by the tumor cells may play an important role in the development of tumor metastasis, mediating through suppression of lymphoid tissues of the host.
We investigated the effect of pilocarpine on the bovine iris sphincter. This muscle contracted in a dose-dependent manner from 2 x 10(-6) M, with a maximal response at 3 x 10(-3) M. The ED50 values was (1.6 +/- 0.3) x 10(-4) M. Pilocarpine generated a desensitization while desensitization was not significant in the case of other cholinergic agents such as acetylcholine (Ach) and carbachol. Desensitization was profoundly increased in the presence of Ach, neostigmine or eserine: the responses to the second and third trials of pilocarpine were reduced to approximately 8-10% or 30% of the corresponding first responses. Pilocarpine reportedly releases transmitters and alters choline-acetyltransferase activity. These results taken together suggest that either variable Ach synthesis, inhibitory transmitter release or possible toxic action in high concentrations may be involved in the pilocarpine-induced responses of the bovine iris sphincter muscle. The desensitization and partial agonist-antagonist action of pilocarpine could not explain the characteristics of the bovine iris sphincter muscle.
Using tension-recording methods, we compared the effects of acetylcholine (Ach) and carbachol on the bovine iris sphincter. The isolated muscle strips were mounted in a 0.2 ml organ bath, through which Krebs solution at 36 degrees C flowed continuously. There was a ten-thousandfold difference in potency between carbachol and Ach in this tissue. Neostigmine or eserine, acetylcholinesterase (AchE) inhibitors, produced a larger contraction of the muscle than did Ach. Ach-induced contractions were potentiated by low doses of anti-AchEs and were inhibited by atropine. This in vitro study suggests that Ach and/or endogenous chemical agents may be spontaneously released from tissues and that AchE activities in this tissue strongly inhibit or mask the Ach action, probably in order to protect the nerve terminals from released Ach.
In order to control visually-guided voluntary movements, the central nervous system (CNS) must solve the following three computational problems at different levels: (1) determination of a desired trajectory in the visual coordinates, (2) transformation of the coordinates of the desired trajectory to the body coordinates and (3) generation of motor command. In this paper, the second and the third problems are treated at computational, representational and hardware levels of Marr. We first study the problems at the computational level, and then propose an iterative learning scheme as a possible algorithm. This is a trial and error type learning such as repetitive training of golf swing. The amount of motor command needed to coordinate activities of many muscles is not determined at once, but in a step-wise, trial and error fashion in the course of a set of repetitions. Actually, the motor command in the (n + 1)-th iteration is a sum of the motor command in the n-th iteration plus two modification terms which are, respectively, proportional to acceleration and speed errors between the desired trajectory and the realized trajectory in the n-th iteration. We mathematically formulate this iterative learning control as a Newton-like method in functional spaces and prove its convergence under appropriate mathematical conditions with use of dynamical system theory and functional analysis. Computer simulations of this iterative learning control of a robotic manipulator in the body or visual coordinates are shown. Finally, we propose that areas 2, 5, and 7 of the sensory association cortex are possible sites of this learning control. Further we propose neural network model which acquires transformation matrices from acceleration or velocity to motor command, which are used in these schemes.
One hundred and two consecutive non selected patients with intracranial aneurysms were reviewed. The incidence of ruptured aneurysm was 17.5 per population of 100,000 per year. The patients were divided into two groups, according to a change of policy that reversed the timing of operations from delayed to early surgery. The overall mortality and occurrence rate of neurological deficits due to vasospasm in patients in Hunt and Kosnik grades I through III were found to be lower during the period with a policy of early surgery. Elderly patients over 70 years old constituted 19% of the cases and those in poor condition (grade IV and V) 31%. These figures in this study are high, which may reflect the fact that these are common problems inherent in the treatment of ruptured aneurysms without patient selection at most community hospitals in the forefront of primary medical care.
Prolactin (PRL) was extracted with acid-acetone from common carp (Cyprinus carpio) pituitary glands and purified by gel filtration on Sephadex G-75, ion-exchange chromatography on DEAE-cellulose, and reversed-phase high-performance liquid chromatography (HPLC) on TSK-gel TMS 250 with a yield of 0.7 mg/g wet tissue. At each stage of purification, fractions were monitored by HPLC on TSK-gel ODS 120T and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Carp PRL was almost equipotent with ovine PRL in retaining plasma Na concentrations in the hypophysectomized killifish, Fundulus heteroclitus. Immunocytochemistry at both the light and electron microscopic levels revealed that carp PRL antiserum specifically stained cells in the goldfish rostral pars distalis. No cross reaction with putative growth hormone (GH) cells in the proximal pars distalis was observed. The specificity of the carp PRL antiserum was confirmed by immunoblot studies. Although immunostaining of both carp and salmon PRL was observed, there was no cross reaction to GHs from these species. Carp PRL had a sole N-terminal residue of valine, a molecular weight of 23 kDa in SDS-PAGE, and an isoelectric point of 7.3 by gel electrofocusing. Based on these results, together with the knowledge of physicochemical properties of salmon and tilapia PRLs, we propose a standard procedure for isolation of fish PRLs.
The prevalence and clinical pictures of Mycoplasma pneumoniae infections among children were studied using culture and serological techniques. The isolation rate was 22% (195 of 885) in pneumonic patients and 11% (66 of 600) in non-pneumonic patients. In patients three years of age or less, M. pneumoniae was isolated at the same rate from febrile and afebrile cases and from wheezy and non-wheezy cases. In older patients, however, M. pneumoniae was frequently isolated from febrile but non-wheezy cases. A peak in the number of the positive isolates was found in patients who were four years old. The peak number of M. pneumoniae infections at age four was confirmed serologically. This peak was in patients who were younger than those previously reported.
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