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Biomedical subjects

S Minami

Publications and source records attributed to S Minami.

At least 289 records · Page 16Linked to original sources
PubMed1988

[Surgery for spine tumors].

One hundred and nine patients with spine tumors were treated surgically at Chiba University Hospital and Chiba Cancer Center in 1977-1987. The primary spine tumors included 9 chordomas, 6 myelomas and 5 giant cell tumors. The metastatic spine tumors were from primary lesions of the lung, breast, kidney, thyroid, prostate, and unknown origin. Fifty-eight patients were treated surgically by the posterior procedure, 18 with the anterior procedure and 33 with the combined anterior and posterior procedure. According to Frankel's classification, changes in neurological status were evaluated. In the patients classified as degree A, B or C by Frankel's classification before surgery, 56% showed improvement of neurological deficit. With regard to pain, about 90% of patients treated with surgical decompression and stabilization had pain relief, although only 42% of 21 patients given laminectomy alone experienced pain relief. Among the patients treated with the anterior procedure or combined anterior and posterior procedure, 60% of non-ambulatory patients were ambulatory after surgery, but in patients treated with the posterior procedure, only 48% of non-ambulatory patients were ambulatory after surgery. In planning of the surgical treatment of spine tumors, immediate surgical decompression and stabilization should be indicated before complete paralysis develops due to rapid deterioration of neurological status, after which the anterior approach for anterior lesions and the combined approach for extensive lesions is indicated.

Adenocarcinoma↗
PubMed1987

Topographic estimations by component spectroanalysis of two formazans of nitroblue tetrazolium in tissue sections.

A component-spectroanalysis technique was used to study the multicolor properties of histochemically stained tissue sections. We developed a method that makes it possible to obtain separately both the spectral patterns and spatial distributions of different color components in tissue sections. To illustrate the application of this technique, we examined the extinction spectrum of reduced nitroblue tetrazolium (NBT), which is used for the detection of dehydrogenase activity. Upon the reduction of NBT, mono- and diformazans are formed, and these exhibit over-lapping extinction spectra. When succinate dehydrogenase (SDH) activity in rat liver lobules was examined using NBT, monoformazan was found to be present at higher concentrations than diformazan and to have a uniform distribution, whereas the concentration of diformazan increased with a steep gradient between the center and periphery of lobules. In rat skeletal muscle fibers, diformazan was present at higher concentrations than monoformazan. The level of SDH activity was topographically represented by the hydrogen concentration calculated from the concentrations of the two formazans. This method is effective for separating multiple components such as mono- and diformazans in histochemical reactions.

Animals↗
PubMed1987

Dendritic activities of spinal motoneurones in pigs and rabbits enhanced through chronic stimulation of a dorsal root.

1. The L6 or L7 dorsal root in 7-10-day-old pigs was chronically stimulated for 3 or 4 h a day for 4 days/week. The stimuli were 50 or 500 Hz pulse trains delivered at 0.5/s. The induced movements were limited to the hip and hind leg on the stimulated side without any sign of pain. There was evidence that not only the monosynaptic, but also polysynaptic pathways to the motoneurones were chronically stimulated. After 2-6 days of chronic stimulation, all pigs were studied in acute experiments either under pentobarbitone (Nembutal) anaesthesia or in the decerebrated state. Normal (unstimulated) 15-28-day-old pigs were also studied in acute experiments under similar conditions, as the controls. 2. In thirty-three out of fifty-six motoneurones of normal pigs there were all-or-none potentials of 2-6 ms duration and 1-5 mV amplitude. These have been named D-spikes. They occurred in response to tibial nerve and/or dorsal root stimulation and/or spontaneously. They could be abolished by injection of a hyperpolarizing current. These results show that D-spikes are different from any of the well-established all-or-none events of the motoneurone, i.e. the spikes of the axon, initial segment, soma and unitary excitatory post-synaptic potentials. Several kinds of D-spikes could exist in the same motoneurone, as judged from their wave forms and thresholds. This argues for the dendrites as the sites of origin for D-spikes, because only the dendrites can have multiple sites for spike generation. D-spikes were shown to summate to form a larger depolarization. 3. In pigs chronically stimulated with 500 Hz pulses seventy-five motoneurones were studied in acute experiments. In sixty-one motoneurones D-spikes were observed. This indicated that D-spike occurrence was enhanced in the chronically stimulated motoneurones as compared with controls. 4. Characteristic of the chronically stimulated motoneurone was the presence of a depolarization of all-or-none nature which was more than 10 ms in duration and 2-12 mV in amplitude. The depolarization is referred to as the D-wave. The D-wave was similar in properties to the D-spike described above, except that it was of longer duration. Consequently, it is assumed that the D-wave is summed D-spikes. D-waves were observed in nineteen motoneurones.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗
PubMed1987

Ovarian cystic teratomas: MR imaging.

Magnetic resonance (MR) imaging characteristics of ovarian cystic teratomas were evaluated in 18 patients with 23 surgically proved tumors. The fat within the tumor demonstrated characteristic intensity similar to that of subcutaneous fat and a pathognomic pattern of chemical shift artifact that helped differentiate ovarian cystic teratomas from endometrial cysts. In addition to fat, MR images of ovarian cystic teratomas had several other characteristics that allowed confident diagnosis, including gravity-dependent layering or floating debris, palm tree-like protrusions or rounded nodules (dermoid plugs), and, occasionally fat-fluid levels and globular calcification. MR images were diagnostic in 20 tumors and were able to depict a tumor measuring 2 cm in diameter. MR imaging appears to be valuable in problematic cases in which other modalities are not diagnostic.

Adolescent↗
PubMed1987

Hepatocellular carcinoma: MR imaging.

Sixty patients with hepatocellular carcinoma (HCC) were studied with computed tomography (CT) and magnetic resonance (MR) imaging at 1.5 T. MR imaging was equivalent to CT in detection of HCC. MR imaging was superior to CT in demonstrating the details of tumors, especially pseudocapsules. In 58 cases, main tumors were detected with MR imaging. On spin-echo (SE) 600/25 (repetition time msec/echo time msec) sequences, tumors were hyperintense in 18 cases, isointense in ten, and hypointense in 30. On SE 2,000/60 sequences, all but two tumors had high signal intensity. Pseudocapsules, intratumoral septa, daughter nodules, and tumor thrombi, which are important characteristics of HCC, were demonstrated in 22, three, six, and six cases, respectively, on MR imaging. MR imaging is useful for characterizing the internal architecture of HCC.

Adult↗
PubMed1987

Moyamoya disease: MR imaging.

Eleven patients with moyamoya disease were studied with magnetic resonance (MR) imaging performed with a high-field-strength (1.5-T) superconducting magnet. In all cases a fundamental pathologic change of moyamoya disease--occlusion or stenosis of the terminal portion of the internal carotid artery and the proximal portion of anterior and middle cerebral arteries--was clearly demonstrated. The characteristic collateral network from the suprasellar cistern to the basal ganglia, which corresponds to the "moyamoya vessels" on angiograms, was seen in several patients. Various ischemic changes, including infarction, brain atrophy, and ventricular dilatation, were also well demonstrated. MR imaging plays an important role in the diagnosis of moyamoya disease.

Adolescent↗
PubMed1987

Transection of the pituitary stalk: development of an ectopic posterior lobe assessed with MR imaging.

Magnetic resonance (MR) imaging was performed in ten patients with pituitary stalk transection who had idiopathic pituitary dwarfism. Contiguous sagittal T1-weighted images were obtained in all cases, and, in some, axial or coronal images were taken for further evaluation. On MR images, normal anterior and posterior lobes of the pituitary gland can be clearly differentiated because the posterior lobe has a characteristic high intensity on T1-weighted images. In the ten patients, the high-intensity posterior lobe was not seen, but a similar high signal intensity was observed at the proximal stump in seven patients. This high-intensity area is the newly formed ectopic posterior lobe, which secretes antidiuretic hormone just as the posterior lobe would. When the ectopic lobe completely compensates for the impaired posterior lobe, endocrinologic data indicate normal posterior lobe function. However, MR imaging can reveal the transection of the pituitary stalk and formation of the ectopic lobe.

Adolescent↗
PubMed1987

Component analysis of spatial and spectral patterns in multispectral images. I. Basis.

A new (to our knowledge) theory of component pattern analysis in multispectral images is developed by using the methods of principal component analysis and nonlinear optimization with a nonnegativity constraint. Given images of a scene in different color bands, we estimate both the spectral curves of components included in the image and the spatial pattern corresponding to each spectral curve. In this method, neither spatial nor spectral features of the components are necessary, but the physical rule of nonnegative absorptivity and density nonnegativity is used for any material of any optical frequency at any position in the image. Experimental results of component analysis with real microscopic image data are shown to demonstrate the effectiveness of the proposed method.

Form Perception↗
PubMed1987

A radioimmunoassay for human pro-luteinizing hormone-releasing factor [pro-LRF(14-69)OH].

A radioimmunoassay (RIA) for human pro-LRF(14-69)OH was developed with an antiserum, generated in a rabbit, to [Tyr67]pro-LRF(47-67)NH2 conjugated to BSA. This antiserum bound 28-32% of [125I]pro-LRF(14-69)OH at a final dilution of 1:2500 and the binding was inhibited by pro-LRF(14-69)OH in a dose-dependent manner. The sensitivity of the RIA was 31.2-62.5 pg and the dose that inhibited 50% of the binding to the tracer was 280-320 pg. Intra- and inter-assay coefficients of variation at 50% inhibition were 8 and 12%, respectively. Neither LRF nor pro-LRF(14-37)OH was recognized by the antiserum. The dilution curve generated with human hypothalamic extract was parallel to that of pro-LRF(14-69)OH. In addition the extract yielded a major immunoreactive peak emerging in elution volumes concordant with [125I]pro-LRF(14-69)OH on Sephadex G-50 chromatography.

Antibody Specificity↗
PubMed1987

Role of renal catecholamines in the control of sodium and water excretion: lack of natriuresis by endogenous dopamine in the rat kidney.

The physiological role of dopamine in renal Na and water excretion was studied in rats treated with L-3,4-dihydroxyphenylalanine (L-DOPA), haloperidol or 6-hydroxydopamine for 1 week. Daily-pooled urine samples, plasma, and kidneys were obtained from the experimental groups and untreated controls. Urinary dopamine was markedly elevated in L-DOPA-treated and transiently decreased in haloperidol-treated rats. Urinary epinephrine, but not norepinephrine was increased in the L-DOPA and haloperidol groups. However, there was no significant difference in urine volume, urinary Na, urinary K, plasma Na and K levels between the experimental groups and controls, except for 6-hydroxydopamine-treated rats. They showed a definite increase in urinary volume, Na, K and aldosterone excretion, whereas the renal norepinephrine and epinephrine content was reduced. Urinary cAMP and Na-K ATPase activity were also similar in all groups, whereas renal cAMP content and aromatic amino acid decarboxylase activity were significantly increased in the L-DOPA and haloperidol groups, suggesting an activated catecholamine synthesis in the kidney. [3H]haloperidol binding was also increased by the L-DOPA and 6-hydroxydopamine administration, but the half maximal displacement dose was similar in all groups (6.4 x 10(-9)mol/l), indicating an increase in the number of dopamine binding sites. These results indicate that 1) in contrast to the pharmacological effect of dopamine, locally-formed dopamine has no direct natriuretic action in the kidney; 2) an enhanced production of dopamine in the kidney does not suppress aldosterone secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Direct radiographic magnification with computed radiography.

Computed radiography was combined with a 0.1-mm microfocus radiographic tube to obtain radiographic magnification of a x3 to x5. Gray-scale image processing compensated for the loss of radiographic contrast associated with the high-kilovoltage, short-exposure technique. The high-pass spatial frequency filtering capability of the computed radiography resulted in enhanced edges and increased displayed latitude. The improved image quality obtained by magnification computed radiography allowed delineation of subtle abnormalities and small anatomic structures not apparent on conventional screen-film contact or magnification radiographs.

Humans↗
PubMed1987

Potassium perchlorate, potassium iodide, and propylthiouracil: promoting effect on the development of thyroid tumors in rats treated with N-bis(2-hydroxypropyl)-nitrosamine.

The effect of 1000 ppm potassium perchlorate (KClO4), 1000 ppm potassium iodide (KI) or 1000 ppm propylthiouracil (PTU) in the diet on the development of thyroid tumors was studied histologically and biochemically in Wistar rats given a single ip injection of 280 mg of N-bis(2-hydroxypropyl)nitrosamine (DHPN) per 100 g body weight. Basal diet containing 100 ppm KClO4, 1000 ppm KI or 1000 ppm PTU was given for 19 weeks from week 2 to week 20. The incidence of thyroid adenomas at the end of week 20 of the experiment was 100% (20/20) in rats treated with DHPN followed by KClO4, 85% (17/20) in rats given DHPN followed by KI, 95% (19/20) in rats given DHPN followed by PTU, and 5% (1/20) in rats given DHPN alone. The incidence of thyroid cancers was 100% (20/20) in rats treated with DHPN followed by KClO4, 65% (13/20) in rats treated with DHPN followed by KI and 0% (0/20) in rats treated with DHPN followed by or not followed by PTU. Rats given KClO4, KI or PTU alone and untreated rats had no thyroid tumors. The mean values of TSH in serum were 2.94 +/- 0.79 ng/ml in rats treated with DHPN followed by KClO4, 9.40 +/- 16.0 ng/ml in rats treated with DHPN followed by KI and 60.94 +/- 20.60 ng/ml in rats treated with DHPN followed by PTU. It was confirmed that (1) KClO4, PTU and KI promote the development of thyroid tumor in rats treated with DHPN, (2) the promoting effect of KClO4 or KI is stronger than that of PTU and (3) the value of TSH in serum is not parallel to the promoting effect on the development of thyroid tumor.

Animals↗