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Biomedical subjects

S Yamane

Publications and source records attributed to S Yamane.

At least 55 records · Page 3Linked to original sources
PubMed1996

Evaluation of double filtration plasmapheresis, thermofiltration, and low-density lipoprotein adsorptive methods by crossover test in the treatment of familial hypercholesterolemia patients.

A comparative assessment has been made regarding efficacy and safety of the double filtration plasmapheresis (DFPP), thermofiltration (TFPP), and low-density lipoprotein (LDL) adsorptive (PA) methods by making a crossover test on heterozygous familial hypercholesterolemia patients. Treatments by DFPP, TFPP (secondary membrane Evalux 5A), and PA (Liposorber LA-40) were carried out 5 times each, with a 2-week interval, in 5 patients with heterozygous familial hypercholesterolemia. The same plasma separator (Plasmacure PS-60, polysulfone) was used in all cases, and the volume of plasma processed was set at 4 L. High removal rates were obtained of total cholesterol, LDL cholesterol, triglycerides TG, and apolipoprotein B (apoB) by all three methods, and no differences were observed. Lipoprotein (a), apoA-2, apoC-3, fibrinogen, and immunoglobulin M (IgM) showed significantly high removal rates by the DFPP and TFPP methods compared with the PA method. The sieving coefficient of albumin and high-density lipoprotein (HDL) cholesterol at 2 and 4 L of plasma processed exhibited high permeabilities using all three methods. Supplementing albumin was not necessary. An increase of the transmembrane pressure was observed in 1 case treated by DFPP but was not observed when using the TFPP or PA method. No changes were observed in serum interleukin 1beta (IL-1beta) or tumor necrosis factor-alpha (TNF-alpha) before and after treatment by any of the three methods. No remarkable side effects were observed using either the DFPP or TFPP method. The DFPP and TFPP methods showed efficacy and safety that was not inferior to the PA method in conventional LDL apheresis, and the dead-end method of the filter operation without the discarding of plasma was shown to be possible.

Adsorption↗
PubMed1996

[Intra-operative management during laparotomy for patients under hemodialysis].

We evaluated retrospectively 31 patients under hemodialysis who underwent scheduled laparotomy with a purpose to determine the optimal intra-operative water balance. The patients fell into two different periods according to the difference of the principle of anesthesia. Anesthesia method employed for the former eleven patients (1987.6-1990.12) was NLA with pancuronium for muscle relaxation and they were ventilated mechanically in ICU. More recent twenty patients (1991-1995) had epidural block plus nitrous oxide-oxygen-isoflurane with vecuronium and they were extubated early. These latter patients, compared with the preoperative values, did not show any significant changes in mean arterial pressure or systemic vascular resistance after the operation. Intra-operative water balance showed a positive correlation with PADP (r = 0.57) and a negative correlation with SVR (r = 0.36) at the end of operation. The adequate fluid infusion is necessary to maintain PADP, and the water balance of +3-5 ml x kg-1 x hr-1 is recommended during laparotomy for the patients under hemodialysis.

Anesthesia, General↗
PubMed1994

Mechanisms of the in vitro antimutagenic action of chlorophyllin against benzo[a]pyrene: studies of enzyme inhibition, molecular complex formation and degradation of the ultimate carcinogen.

Mechanisms of the antimutagenic action of chlorophyllin (CHL) towards benzo[a]pyrene (BP) were studied in vitro. In the Salmonella assay, CHL inhibited the mutagenic activity of BP in the presence of an S9 activation system and was particularly effective against the direct-acting ultimate carcinogen, benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE). Spectral studies indicated that the time-dependent hydrolysis of BPDE to tetrols was augmented in the presence of CHL concentrations on the order of 5 microM. Dose-related inhibition of several cytochrome P450-dependent enzyme activities was observed upon addition of CHL to in vitro incubations. Spectral changes for the interaction between CHL and cytochrome P450 indicated that CHL does not bind to the active site of the enzyme, but exerts its inhibitory effect indirectly. This was achieved by inhibiting NADPH-cytochrome P450 reductase (Ki approximately 120 microM with cytochrome c as substrate), and did not involve lowering of the effective substrate concentration by complex formation with the procarcinogen. It is concluded that the in vitro antimutagenic activity of CHL towards BP involves accelerated degradation of the ultimate carcinogen, with inhibition of carcinogen activation occurring only at high CHL concentrations. The latter mechanism is unlikely to occur in vivo following p.o. administration due to the limited uptake of CHL from the gut, but tissue concentrations may be sufficiently high to cause degradation of BPDE.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1994

High-performance liquid chromatography-thermospray mass spectrometry of epoxy polyunsaturated fatty acids and epoxyhydroxy polyunsaturated fatty acids from an incubation mixture of rat tissue homogenate.

A method for the analysis of epoxy polyunsaturated fatty acids (EpPUFAs) and epoxyhydroxy polyunsaturated fatty acids (EpHPUFAs) in rat tissue homogenate, with homo-gamma-linolenic acid (20:3, n - 6), arachidonic acid (20:4, n - 6), eicosapentaenoic acid (20:5, n - 3) or docosahexaenoic acid (22:6, n - 3) as a substrate, has been developed. Extraction with dichloromethane at pH 4-5 and concentration in the presence of pyridine were performed. Spectral analysis of chromatograms obtained with high-performance liquid chromatography-thermospray mass spectrometry showed the presence of EpPUFAs, EpHPUFAs and dihydroxy metabolites (DiHPUFAs) of EpPUFAs corresponding to each precursor fatty acid. On a selected-ion monitoring chromatogram, many EpPUFAs, EpHPUFAs and DiHPUFAs in an extract from an incubation mixture of each precursor fatty acid in aged rat tissue homogenate were detected simultaneously within 70 min. EpPUFAs and DiHPUFAs derived from 20:3 (n - 6) or 20:5 (n - 3) were detected in significant amounts. From these results, a highly active cytochrome P450 system or non-enzymic oxidative reactions in aged rat tissue homogenate were suggested.

Animals↗
PubMed1994

Neural activity in cortical area MST of alert monkey during ocular following responses.

1. We studied response properties of neurons in the superior temporal sulcus (STS) of behaving monkeys that discharged during brief, sudden movements of a large-field visual stimulus, eliciting ocular following. Most neurons responded to movements of a large-field visual stimulus with directional selectivity, preferring high stimulus speeds. Neurons were mostly recorded in the medial superior temporal area (MST) (187/250) and the middle temporal area (MT) (57/250). Further response properties were studied in the MST neurons. 2. Response latencies were measured when a large-field random dot pattern was moved in the preferred direction and preferred speed for each neuron. Eighty percent (120/150) of the neurons were activated < 50 ms after the onset of the stimulus motion. In most cases (89%, 134/150), increased firing rates started before the eye movements, with 59% (88/150) starting > 10 ms before the eye movements. 3. The relationship between the latency of neuronal responses and that of eye movements was studied in 59 neurons by changing the stimulus speed systematically (10-160 degrees/s). The latencies of both neuronal and ocular responses decreased as stimulus speed increased. As a result, the time difference between the response latencies for neuronal and ocular responses varied little with changes in stimulus speed. 4. Blurring of the random dot pattern, by interposing a sheet of ground glass, increased the latency of both neuronal responses and eye movements. 5. With the use of a check pattern instead of random dots, both neuronal and ocular responses began to decrease rapidly when the temporal frequency of the visual stimulus exceeded 20 Hz. At 40 Hz the neurons showed a distinctive burst-and-pause firing pattern, and the eye movements showed signs of oscillation. 6. The response properties of the MST neurons during ocular following were similar to those of the dorsolateral pontine nucleus (DLPN) neurons, reported previously. Our results indicate that the MST neurons may provide visual information to the DLPN neurons and may play a role in eliciting ocular following. 7. Responses during smooth-pursuit eye movement were studied in 55 MST neurons. Each of these neurons responded to the moving large-field visual stimulus, which elicited ocular following, and 40 of these neurons were activated during smooth pursuit in the dark. Response latencies during smooth pursuit were long in those neurons having different directional preferences during smooth pursuit and ocular following but were short for those having the same directional preferences during smooth pursuit and ocular following.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1994

Simple monitoring system for R-mediated site-specific recombination on chromosomes in Saccharomyces cerevisiae.

A simple measuring system for the frequency of recombinant clones generated by R-protein mediated recombination was constructed. By applying the system, the frequencies of recombinant clones due to site-specific recombination between two loci on one or two different nonhomologous chromosome(s) were monitored during cultivation. Subsequently, it was found that the frequencies increase nearly in proportion to the culture period and are different among the individual two selected loci. Thus, the system is thought to be a candidate for analyzing physicochemical situations, such as folding and localization, of chromosomes in the nucleus.

Bacterial Proteins↗
PubMed1993

Isolation of Babesia gibsoni piroplasms from infected erythrocytes of dogs.

To eliminate the influence of anti-dog erythrocyte membrane antibodies in Babesia gibsoni-infected dogs on the immunological investigations of parasites, an attempt was made to purify B. gibsoni piroplasms from infected erythrocytes by N2 cavitation and centrifugation in a Percoll discontinuous density gradient. Although electron microscopic examination revealed that the concentrated piroplasms visible as a band at the interface between 30% and 40% Percoll solutions were contaminated with a small amount of erythrocyte membrane debris, little contamination was detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western immunoblots. Hence, the isolated parasites may be usable for immunological examinations of parasites.

Animals↗
PubMed1992

High-performance liquid chromatography-thermospray mass spectrometry of hydroperoxy polyunsaturated fatty acid acetyl derivatives.

A method for the analysis of hydroperoxy polyunsaturated fatty acids was developed. The hydroperoxy groups were acetylated by acetic anhydride, and the mixture was partially purified on a Sep-Pak C18 cartridge and analysed by high-performance liquid chromatography with thermospray mass spectrometry. Generally, the base ion, [M+H - n(60)]+ or [M+H - n(60) - n(H2O)]+, is produced through elimination of acetic acid or water (n = number of hydroperoxy groups). The detection limit for these derivatives was ca. 1 pmol at concentrations of hydroperoxy polyenoic acids prior to derivatization. Using this method, many hydroxy and hydroperoxy polyunsaturated fatty acid derivatives could be detected simultaneously within 30 min on a selected-ion monitoring detection chromatogram without a gradient system. The assay was successfully applied to hydroxy and hydroperoxy polyunsaturated fatty acids from an incubation mixture of rat brain homogenate to which polyunsaturated fatty acids had been added.

Acetylation↗
PubMed1992

Sparse population coding of faces in the inferotemporal cortex.

How does the brain represent objects in the world? A proportion of cells in the temporal cortex of monkeys responds specifically to objects, such as faces, but the type of coding used by these cells is not known. Population analysis of two sets of such cells showed that information is carried at the level of the population and that this information relates, in the anterior inferotemporal cortex, to the physical properties of face stimuli and, in the superior temporal polysensory area, to other aspects of the faces, such as their familiarity. There was often sufficient information in small populations of neurons to identify particular faces. These results suggest that representations of complex stimuli in the higher visual areas may take the form of a sparse population code.

Animals↗
PubMed1992

Neural activity in dorsolateral pontine nucleus of alert monkey during ocular following responses.

1. Movements of the visual scene evoke short-latency ocular following responses. To study the neural mediation of the ocular following responses, we investigated neurons in the dorsolateral pontine nucleus (DLPN) of behaving monkeys. The neurons discharged during brief, sudden movements of a large-field visual stimulus, eliciting ocular following. Most of them (100/112) responded to movements of a large-field visual stimulus with directional selectivity. 2. Response amplitude was measured in two components of the neural response: an initial transient component and a late sustained component. Most direction-selective DLPN neurons showed their strongest responses at high stimulus speeds (80-160 degrees/s), whether their response components were initial (63/87, 72%) or sustained (63/87, 72%). The average firing rates of 87 DLPN neurons increased as a linear function of the logarithm of stimulus speed up to 40 degrees/s for both initial and sustained responses. 3. Not only the magnitude but also the latency of the neural and ocular responses were dependent on stimulus speed. The latencies of both neural and ocular responses were inversely related to the stimulus speed. As a result, the time difference between the response latencies for neural and ocular responses did not vary much with changes of stimulus speed. 4. Response latency was measured when a large-field random dot pattern was moved in the preferred direction and at the preferred speed of each neuron. Seventy-three percent (56/77) of the neurons were activated less than 50 ms after the onset of the stimulus motion. In most cases (67/77, 87%), their increase of firing rate started before the eye movements, and 34% of them (26/77) started greater than 10 ms before the eye movements. 5. Blurring of the random dot pattern by interposing a sheet of ground glass increased the latency of both neural responses and eye movements. On the other hand, the blurred images did not change the timing of the effect of blanking the visual scene on the responses of the neurons or eye movements. 6. When a check pattern was used instead of random dots, both neural and ocular responses began to decrease rapidly when the temporal frequency of the visual stimulus exceeded 20 Hz. When the temporal frequency of the visual stimulus approached 40 Hz, the neurons showed a distinctive burst-and-pause firing pattern. The eye movements recorded at the same time showed signs of oscillation, and their temporal patterns were closely correlated to those of the firing rate.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

On oscillating neuronal responses in the visual cortex of the monkey.

1. Recent studies of visual processing in the cat have shown stimulus-related oscillations in the 30- to 70-Hz range. We sought to replicate these findings in the monkey. 2. We recorded multiunit activity (MUA) and local field potentials (LFP) in areas V1 and middle-temporal area (MT), and MUA from the inferotemporal cortex (IT) of monkeys (Macaca fuscata). Recordings in all areas were made under conditions of anesthesia as close as possible to those in previous studies of oscillating responses in the cat. In addition, we recorded MUA in the IT of behaving monkeys while the monkeys performed a face discrimination task. 3. In areas V1 and MT, LFP power spectra showed broadband increases (1-100 Hz) in amplitude on stimulation by swept optimally oriented light bars, and not a shift in power from low to midfrequency, as has been reported in the cat. 4. MUA autocorrelograms (ACGs) classified by fitting Gabor functions, showed oscillations at approximately 10% of recording sites in V1 and MT, but these oscillations were in the alpha range (12-13 Hz). 5. MUA ACGs from IT in the anesthetized monkey showed no oscillations. 6. For MUA ACGs from IT in the behaving monkey, only two recording sites (out of 50) showed an oscillating response, with frequencies of 44 and 48 Hz. One oscillating response was associated with stimulation, and the other was associated with the absence of stimulation. 7. The very low incidence in the monkey of oscillating responses in the 30- to 70-Hz range (2 in 424 recordings made at 142 recording sites) and the absence of stimulus dependence suggest that such oscillations are unlikely to serve a function in the monkey, and that there may be a species difference between monkey and cat in the dynamics of neural activity in the visual cortex. 8. We found that methods of classifying responses as oscillating used in some of the studies of the cat may have led to overestimation of both the number of sites showing oscillation and the number of pairs of sites showing phase coherence. These problems arise from the failure to take account of badness of fit between Gabor functions and their corresponding ACGs, and from Gabor functions "ringing" in response to short phasic phenomena that could be consistent with nonoscillatory activity.

Action Potentials↗
PubMed1992

Color selectivity of neurons in the inferior temporal cortex of the awake macaque monkey.

We tested the color selectivity of neurons in the inferior temporal (IT) cortex of two awake macaque monkeys. A color stimulus was presented at the center of the visual field while the animal performed a fixation task. The responses of single units to various colors were recorded and were plotted in a color space. The color space was based on the CIE (Commission Internationale de l'Eclairage) chromaticity diagram. Quantitative analysis of the color selectivity was performed using a standard set of colors that were evenly distributed in the color space. Sixty-five neurons recorded from eight guide tubes implanted in anterior part of IT cortex were tested quantitatively, and their color selectivity was statistically evaluated. Forty-six of them (71%) were classified as color selective. Color-selective cells responded to some colors but not to others, and we called the responsive region in the color space the "color field." The location and the size of a cell's color field were largely independent of the luminance of the stimulus. About 80% of the color-selective neurons had color fields consisting of a single responsive region that were restricted in some part of the color space, and the remaining cells had more than one responsive region within the color space. Preferred hues of the color-selective neurons differed from cell to cell. The population of cells together covered nearly all of the color space. There was a tendency for more color-selective cells to be less sensitive to white and desaturated cyans. Some of the cells with color fields that consisted of more than one responsive region were more sensitive to saturation of the stimulus than to its hue. Although previous electrophysiological studies in IT cortex emphasized the pattern selectivity of the neurons, our results suggest that color is an important factor in the role that IT cortex plays in the object recognition.

Analysis of Variance↗
PubMed1991

Clinical experience of double filtration plasmapheresis for drug refractory neurological diseases.

The effect of therapeutic double filtration plasmapheresis (DFPP) was clinically investigated for drug refractory neurological disorders. DFPP therapy was performed 181 times for 10 patients who were treated with medical therapy of steroid or immunosuppressive drugs without any improvement of their symptoms. After the induction of DFPP therapy the neuromuscular disturbances were soon ameliorated in 9 cases of them. After DFPP, serum levels of IgG, IgA or IgM were decreased as follows: IgG 0.53 +/- 0.16; IgA 0.60 +/- 0.11; IgM 0.59 +/- 0.09 (M +/- SD). After the DFPP therapy there was no relapse in improved 9 cases. But we could not regard the immunologic markers as the index of efficacy of DFPP. Because serum levels of IgG, IgA or IgM showed a tendency to decrease by using drugs, when we didn't observe any improvement of symptoms. These results suggest that DFPP is a beneficial therapy for neurological diseases who had no effect with drug therapy, however, serum concentrations of the immunologic markers were not necessarily correlated to the severity.

Adolescent↗
PubMed1990

Comparison of prostacyclin production of human gastroepiploic artery and saphenous vein.

The prostacyclin production of the gastroepiploic artery (GEA) and saphenous vein (SV) were studied in 5 patients undergoing coronary artery revascularization. The GEA produced 90.0 +/- 11.9, 132.4 +/- 13.7, and 191.1 +/- 21.8 pg/mg tissue (mean +/- standard error of the mean) of 6-keto-prostaglandin F1 alpha (prostacyclin metabolite) after 2.5, 5.0, and 10.0 minutes, respectively, of incubation in Krebs-Henseleit buffer at 37 degrees C. The SV produced 39.8 +/- 7.0, 66.7 +/- 9.1, and 123.6 +/- 15.1 pg/mg tissue of 6-keto prostaglandin F1 alpha after 2.5, 5.0, and 10.0 minutes, respectively, of incubation. The GEA produced significantly more 6-keto-prostaglandin F1 alpha than SV at all three sampling times up to ten minutes of incubation (p less than 0.01). Prostacyclin is a potent vasodilator and an inhibitor of platelet aggregation. Prostacyclin production by the internal mammary artery was reported to be much higher than that of SV, and the patency rate of internal mammary artery grafts is reported to be better than that of SV grafts in coronary artery revascularization. Therefore, our results suggest that the patency rate of GEA grafts may be better than that of SV grafts in coronary artery revascularization. The GEA is a promising and excellent graft from the biochemical point of view.

6-Ketoprostaglandin F1 alpha↗
PubMed1990

[A well-differentiated hepatocellular carcinoma within adenomatous hyperplasia].

A 37-year-old male was admitted to hospital for jaundice and ascites. An ultrasonogram revealed a hypoechoic mass located in the right anterior inferior segment. A needle specimen of the liver was taken, and its biopsy led to a histological diagnosis of a hepatocellular carcinoma. The patient subsequently underwent an operation wherein it was found that the resected tumor that was taken was not clearly demarcated from the cirrhotic parenchyma. The histological diagnosis was an adenomatous hyperplasia. In a portion of this adenomatous hyperplasia, highly consistent hepatic cells and pseudogland formations were seen, confirming the diagnosis of a well-differentiated hepatocellular carcinoma within an adenomatous hyperplasia.

Adult↗
PubMed1990

[Prospective study on natural evolution of 99mTc-MDP bone scan in asymptomatic total hip arthroplasty].

Natural history of bone scan in forty three patients (55 joints) with asymptomatic total hip arthroplasty was evaluated. Bone uptake of 99mTc-MDP in regions of the acetabulum and femoral shaft, except the marginal acetabulum, became normal on one year post-operation. Radiographic detection of clear zone between bone and cement interface was common and increased with time after the arthroplasty. The post-operative natural change observed by radiography and scintigraphy at the site of the roof of acetabulum was statistically significant (p less than 0.01) by the chi-square test. This may imply that differentiation of true mechanical loosening from asymptomatic natural change at the site of the acetabulum in total hip arthroplasty is difficult. Our results presented here may help diagnosis of delayed complications in total hip replacement by bone scan.

Acetabulum↗
PubMed1989

[An epidemiologic study on patients with lung disease, using a data base management system and the histopathologic diagnosis].

A new pathologic data base management system was introduced in the Section of Pathology, Clinical Laboratory, of this hospital for an efficient sorting and searching past data and for the rapid epidemiological study of them. By the use of this system, the incidence and the age and sex distribution of various diseases were studied in a total of 1,264 patients received pathological examination for surgically operated specimens or biopsied materials at the Chest Disease Research Institute Hospital, Kyoto University, from January, 1986 to December, 1988. A gradual increase in the number of frozen section samples of surgically removed organs and of open lung biopsies was noted during this period. Adenocarcinoma, squamous cell carcinoma, small cell carcinoma and large cell carcinoma amounted to 42.5%, 32.9%, 12.2%, and 7.5% of primary lung cancers, respectively. The male-to-female ratio of patients with primary lung cancers was 2.9:1 but there was no significant difference in the age distribution among four types of the primary cancers in both sexes. Two hundred and ninety nine (32.6%) patients were diagnosed as non-neoplastic lung diseases: 121 infectious (13.2%), 69 granulomatous (7.5%), 62 pulmonary fibrotic (6.8%) and 47 miscellaneous non-neoplastic (5.1%) diseases.

Adult↗