Giant spin-driven ferroelectric polarization in TbMnO3 under high pressure.

The recent research on multiferroics has provided solid evidence that the breaking of inversion symmetry by spin order can induce ferroelectric polarization P. This type of multiferroics, called spin-driven ferroelectrics, often show a gigantic change in P on application of a magnetic field B. However, their polarization (<~0.1 µC cm(-2)) is much smaller than that in conventional ferroelectrics (typically several to several tens of µC cm(-2)). Here we show that the application of external pressure to a representative spin-driven ferroelectric, TbMnO3, causes a flop of P and leads to the highest P (≈ 1.0 µC cm(-2)) among spin-driven ferroelectrics ever reported. We explain this behaviour in terms of a pressure-induced magnetoelectric phase transition, based on the results of density functional simulations. In the high-pressure phase, the application of B further enhances P over 1.8 µC cm(-2). This value is nearly an order of magnitude larger than those ever reported in spin-driven ferroelectrics.

Laparoscopic splenectomy for a giant splenic epidermoid cyst: report of a case.

The use of laparoscopic splenectomy has increased in recent years, primarily for patients with idiopathic thrombocytopenic purpura (ITP). We describe herein the first known case of a laparoscopic splenectomy to be performed in Japan for a patient with a giant splenic epidermoid cyst. A 26-year-old woman presented to our hospital with the major complaint of a feeling of abdominal fullness. Prior to surgery, an ultrasound-guided splenic cyst puncture was conducted for diagnostic purposes as well as to reduce the size of the cyst. The carbohydrate antigen 19-9 (CA 19-9) level was found to be elevated in the cystic contents and in the serum. Under laparoscopic guidance, the splenic vessels were ligated using a device for extracorporeal ligation, then divided. After the resected spleen had been placed in a retrieval bag, it was delivered out of the abdominal cavity without fragmentation. Following surgery, the patient's serum CA 19-9 level returned to normal. Splenic epidermoid cysts are most often encountered in young women, and laparoscopic surgery to remove cysts of this type is both minimally invasive and excellent from a cosmetic standpoint. Thus, laparoscopic surgery should be considered as the method of choice for the majority of patients diagnosed with a splenic epidermoid cyst.

The 3-dimensional representation of EEG distance by use of Shannon-Gelfand-Yaglom information measure during mental arithmetic.

EEG relationships in delta, theta, alpha and beta frequency bands as well as the whole frequency range among 12 electrode locations during resting and mental arithmetic were examined by use of Shannon-Gelfand-Yaglom information measure (SGY) in 10 normal subjects. The EEG relationships were represented in a 3-dimensional (3-D) feature space with multidimensional scaling (MDS). MDS resulted in an anterior-posterior, a left-right and an upper-lower axis. In all 5 frequency bands, the 12 electrodes on the anterior-posterior and left-right axes resembled their actual positions on the scalp during resting and mental arithmetic. During mental arithmetic, prominent changes in the 3-D representation of electrode sites were visualized for activity. The isolation of left and right mid-temporal locations, together with greater EEG distances between left and right mid-temporal locations, were notable during mental arithmetic, suggesting the simultaneous activation possibly in dominant and non-dominant hemispheres and contralateral influences from left to right mid-temporal locations.

Intracellular localization of 8-oxo-dGTPase in human cells, with special reference to the role of the enzyme in mitochondria.

We examined the intracellular distribution of 8-oxo-dGTPase (8-oxo-7,8-dihydrodeoxyguanosine triphosphatase) encoded by the MTH1 gene, a human mutator homologue. The activity of 8-oxo-dGTPase mainly located in cytosolic and mitochondrial soluble fractions of Jurkat cells, a human T-cell leukemia line. Electron microscopic immunocytochemistry, using a specific antibody against MTH1 protein, showed localization of MTH1 protein in the mitochondrial matrix. Activity in the mitochondria accounted for about 4% of the total activity. The specific activity in the mitochondrial soluble fraction (8093 units/mg protein) was as high as that in the cytosolic fraction (8111 unit/mg protein). The 8-oxo-dGTPase activities in cytosolic and mitochondrial soluble fractions co-eluted with MTH1 protein by anion-exchange chromatography, and the molecular mass of the mitochondrial MTH1 protein was much the same as that of the cytosolic MTH1 protein (about 18 kDa). HeLa cells expressing MTH1 cDNA showed an increased cytoplasmic signal together with a weak signal in the nucleus in in situ immunostaining of MTH1 protein, and the overexpressed MTH1 protein was recovered from both cytosolic and mitochondrial fractions. Thus, the 8-oxo-dGTPase encoded by MTH1 gene is localized in mitochondrial and cytosol.

Inter-site EEG relationships before widespread epileptiform discharges.

EEG interactions of the background among locations can start to change just before epileptiform discharges. Such interactions were investigated with relative power contribution analysis based on a multivariate autoregressive model, which permits determination of multiple causal relations of EEGs among locations. EEGs from F3, F4, P3, P4, T3 and T4 were examined in 10 epileptic patients with asymmetric spike and wave complexes (SWCs). A 12.5-s epoch just before SWCs was divided into stationary segments throughout 6 locations with a segmentation method. In segments long before SWCs, most power at each location was generated from its own location. In segments immediately preceding SWCs, contributions from other locations, particularly from the hemisphere with smaller SWCs, increased. Overall EEG relationships among 6 locations were examined by an entropy which measures the uniformness of the spatial distribution of power contribution. The entropy significantly increased gradually toward SWCs. Our findings demonstrated stronger interactions among locations just before epileptiform discharges, suggesting a transitional state from background EEG to epileptiform discharges.

Effect of granulocyte colony-stimulating factor (G-CSF) on chemotherapy-induced oral mucositis.

In this study, the ability of granulocyte colony-stimulating factor (G-CSF) to treat or prevent chemotherapy-induced oral mucositis in patients with advanced breast cancer was evaluated. A total of 14 patients who received intraarterial (i.a.) adriamycin (ADM) preoperatively were divided into two groups according to whether or not G-CSF was given. Thus, group A (n = 7) was given G-CSF and group B (n = 7) was not. G-CSF therapy reduced both the incidence and duration of ADM-induced oral mucositis, and a positive correlation was also seen between the incidence of mucositis and ADM-induced leukopenia (< 2,000/mm3). Group A was further divided into two subgroups according to whether G-CSF was given after or before the leukopenia had dropped below 2,000/mm3: group A-1 (n = 3) and group A-2 (n = 4), respectively. ADM-induced mucositis was observed in two of the three patients in group A-1, but in none of the four patients in group A-2. These results strongly support the idea that G-CSF can effectively treat and prevent ADM-induced oral mucositis.

Moving potential field of frontal midline theta activity during a mental task.

The movement of potential field (potential flow) of frontal midline theta activity (Fm theta) was examined by using optical flow detection techniques in image processing in 6 normal subjects. Electroencephalograms (EEGs) over the fronto-central region were recorded from 13 electrodes around Fz. The potential flow of Fm theta was estimated on a frame which consisted of a square grid of 19 x 19 points in which each of the 13 electrodes was positioned with Fz at the center of grid. The peak-to-trough amplitude distribution was rounded or oval with a maximum just anterior to Fz. In each hemisphere, potential field moved medially in a region anterior to Fz, posteriorly near or at the midline and laterally in a region posterior to Fz. In the temporal sequence of potential field, at each point velocity directions tended to change progressively clockwise or counterclockwise. In the whole frame, a rotary movement of potential flow was found with a center at the middle on each side. Our findings suggested that a potential maximum at the midline may be due to overlapping of fields of opposite direction over the frontal scalp, arising from sources of similar orientation in both hemispheres. It can be assumed that Fm theta propagates in a clockwise direction in the left hemisphere and in a counterclockwise direction in the right hemisphere.

Changes in the fractal dimension of alpha envelope from wakefulness to drowsiness in the human electroencephalogram.

Changes in the fractal dimension of the waxing and waning of alpha activity from wakefulness to drowsiness were investigated in 10 normal subjects. The envelope of filtered alpha activity was estimated with the Hilbert transform. A subset time series was constructed from the alpha envelope data taken at an interval (k). The points of the logarithm of interval k vs. the logarithm of the curve length of the subset time series (log L(k)) were fitted by a two-segment curve, consisting of small and long line segments (segments 1 and 2). The fractal dimension was estimated from the slope of straight line for each segment by using Higuchi's method. The mean fractal dimension was 1.16 for segment 1 and 1.95 for segment 2 during wakefulness and 1.15 for segment 1 and 1.89 for segment 2 during drowsiness. The fractal dimension significantly decreased in both segments during drowsiness, thus, indicating decreases in the complexity of alpha envelope.

Increases in the power spectral slope of background electroencephalogram just prior to asymmetric spike and wave complexes in epileptic patients.

Moment-to-moment electroencephalogram (EEG) changes just before spike and wave complexes (SWCs) were investigated by using a non-stationary power spectral analysis in 10 epileptic patients with asymmetric SWCs. The instantaneous power spectra of background EEG were estimated for a 10-s period just before SWCs in 10 locations. The spectral shape, showing a l/f amplitude characteristic, was assessed by the negative slope (spectral slope) of a straight line on a plot of log power versus frequency. Spectral slope significantly increased toward SWCs at locations with greater SWCs. This finding suggested structural changes in EEG frequency composition just before SWCs because of an epileptogenic process.

[A comparative study on the serum and tissue 5-FU concentrations in patients with hepatocellular carcinoma after preoperative oral administration of UFT and 5'-DFUR].

UFT or 5'-DFUR was orally administered to the patients with hepatocellular carcinoma preoperatively and the concentrations of these drugs and 5-FU in the serum, liver tissue and cancer tissue obtained at the time of operation were measured. The unchanged 5'-DFUR was not detected in any of these samples. The concentration of 5-FU in cancer tissue was significantly higher in UFT treated group (0.409 microgram/g) than that in 5'-DFUR group (0.040 microgram/g). However, the 5-FU levels in the serum and noncancerous liver tissue were also higher than those in the patients with other organ cancers. Although UFT is a useful drug for the adjuvant chemotherapy of hepatocellular carcinoma, the dose was considered to be minimized to avoid the side effects since the activity of drug-metabolizing enzymes may be decreased in hepatocellular carcinoma complicated with liver cirrhosis.

A unique structural feature of rabbit DNA repair methyltransferase as revealed by cDNA cloning.

cDNA encoding rabbit O6-methylguanine-DNA methyltransferase that repairs DNA damaged by alkylating agents was isolated, using as a probe a fragment of mouse cDNA coding for a region containing the active site of the enzyme. The nucleotide sequence of the cDNA revealed that the rabbit methyltransferase is a 181-amino acid polypeptide with a mol. wt of 19,385. Expression of the cDNA in a methyltransferase-deficient Escherichia coli mutant resulted in appearance of a 23 kDa polypeptide with methyltransferase activity, and this rendered the E.coli cells resistant to N-methyl-N'-nitro-N-nitrosoguanidine, in terms of both cell killing and induction of mutation. The rabbit methyltransferase is highly homologous to this enzyme in human, mouse, rat and hamster, but is 26-30 amino acid residues shorter as compared with methyltransferases in other mammalian species. Based on a comparison of the nucleotide sequences for the C-terminal regions of these proteins, we propose that a single base substitution, which would generate a TGA termination codon, was introduced into the sequence for the rabbit enzyme during the process of evolution. Existence of the naturally occurring truncated form of methyltransferase suggests that the longer C-terminal tails of other mammalian methyltransferases may have no significant role in exerting functions of the enzyme in vivo.

Potential flow of frontal midline theta activity during a mental task in the human electroencephalogram.

The movement of potential field (potential flow) of frontal midline theta activity (Fm theta) as well as its potential distribution was examined in 7 subjects by using optical flow detection techniques in image processing. Electroencephalograms (EEGs) over the fronto-central region were recorded from 13 electrodes near the frontal midline (Fz) while the subjects were performing a mental task. The potential flow of Fm theta was estimated on a frame consisting of a square grid with Fz at its center. In regions anterior to Fz, the direction of potential flow was from lateral to medial, whereas it was from medial to lateral in regions posterior to Fz. The peak-to-trough amplitude distribution was round or oval with a maximum just anterior to Fz. The source density distribution showed the greatest potential along the midline in the frontal region and bilaterally symmetric smaller maximum areas mostly in the prefrontal regions. Our findings suggested the presence of 2 different source areas of opposite direction in each hemisphere in spite of a round or oval amplitude distribution.

Localization of activated areas and directional EEG patterns during mental arithmetic.

In a search for the physiological correlates of mental activity, localized EEG desynchronization induced by mental arithmetic was assessed by the entropy of the EEG power spectrum (irregularity index II). The topographic mapping of II can show a localized cortical activation. Directional EEG patterns during mental arithmetic were further examined with a directed mutual information measure (information flow). These two information measures were compared between resting and mental arithmetic conditions in 10 right-handed subjects as well as one left-handed subject. II significantly increased during mental arithmetic in the left temporo-centro-parietal region in right-handed subjects, thus exhibiting its activation. Significant changes in information flow during mental arithmetic were found in the directions mostly from the temporo-centro-parietal region to other areas and within the frontal region in right-handed subjects: information flow from the left temporal and the mid-frontal areas increased and information flow mostly from the left hemisphere decreased. One left-handed subject showed greater II in right post-temporal area. These findings suggest that the left temporo-centro-parietal activation is specific to calculation processing, and the frontal information flow is related to the active performance of mental arithmetic.

[Intra-arterial chemotherapy with granulocyte colony-stimulating factor for breast cancer before surgical treatment].

Intra-arterial chemotherapy (IAC) for far advanced breast cancer is now performed as a routine adjuvant chemotherapy before surgical treatment. However, the following problems remain unsolved; (1) serious adverse reactions such as myelosuppression, (2) unsuccessful insertion of catheter into the internal thoracic artery, and (3) long waiting-period from IAC to surgical treatment. The present studies were conducted to evaluate the utility of a one-route IAC, in which the subclavian artery alone is used, and the efficacy of granulocyte colony-stimulating factor (G-CSF). There was no significant difference in the antitumor effect between the patients with two-route IAC, in which both internal thoracic artery and subclavian artery are used, and the patients with one-route IAC. Administration of G-CSF in combination with IAC reduced both the frequency and the severity of IAC-induced side effects. G-CSF administration during IAC was more effective than after IAC. G-CSF prevented IAC-induced myelo-suppression and/or accelerated recovery from this complication and thus reduced significantly the waiting-period before surgical treatment.

Spindle activity in the waking EEG in older adults.

Sleep spindles are an EEG sign of light sleep under physiological conditions. We reported the simultaneous occurrence of sleep spindles and alpha activity in the waking EEG in 12 patients with a mean age of 59.0 years. Most of the patients were diagnosed as cerebrovascular disorders such as cerebral arteriosclerosis, transient ischemic attack and vascular dementia. The mean alpha frequency in the presence of WSA significantly decreased by 1.5 Hz. The frequency and spatial distribution of waking spindle activity were similar to those of sleep spindles. In our cases, at least the two factors of cerebrovascular involvement and older adults were considered to be primarily responsible for the intrusion of sleep spindles into wakefulness (presumably a state close to very light drowsiness) due possibly to the instability of sleep-waking cycle regulation.

Abnormality of background EEG determined by the entropy of power spectra in epileptic patients.

Relationships between epileptiform discharges and background activity were examined by power spectral entropy (PSE), measuring a degree of EEG irregularity. The EEGs were recorded from 10 electrodes placed at F3, F4, C3, C4, T3, T4, P3, P4, O1 and O2 in 11 epileptic patients with widespread lateralized spike and wave complexes (SWCs). Bipolar records were also made from the antero-posterior derivations. The locations of the maximum PSE coincided with those of the maximum amplitude of SWC in most of the patients. Bipolar derivations with the maximum PSE always included the locations with the maximum PSE obtained from a linked ears reference. Pearson's correlation coefficient between PSE and SWC amplitude was 0.62 +/- 0.14 (mean +/- S.D.) in 11 patients, thus indicating that the scalp distribution of PSE was closely related to that of the amplitude of SWC. These findings suggest that the background EEG is disorganized in or near the epileptogenic focus. A focal background abnormality can therefore be estimated by PSE.

Quantification of EEG irregularity by use of the entropy of the power spectrum.

A new method for quantifying irregularity of EEGs is proposed in this study. The entropy, an information measure, determines the uniformity of proportion distribution. The peakedness or flatness of the distribution of the EEG power spectrum, representing EEG rhythmicity, can be measured by the entropy, because the power spectrum consists of proportions of power at each frequency. The irregularity of the EEG was measured by the entropy of the power spectrum, called an irregularity index (II). The II was obtained from the power spectrum at F3, F4, C3, C4, P3, P4, O1 and O2 during rest and mental arithmetic in 10 normal subjects. Relative band powers of delta, theta, alpha and beta bands and alpha peak frequency were also obtained. EEGs during rest were significantly more irregular anteriorly than in the occipital areas. Alpha activity was also more irregular in the anterior region. A greater degree of EEG desynchronization during mental arithmetic was found over the left hemisphere and the right occipital area. The II was more sensitive to such desynchronization than alpha band power and alpha peak frequency. The differences in spectral structures between rest and mental arithmetic conditions, mainly over the left hemisphere, were also confirmed by the Kullback-Leibler information.

Metastatic carcinoma of the gallbladder from renal cancer presenting as intraluminal polypoid mass.

We report a rare case of secondary involvement of the gallbladder by metastatic renal cell carcinoma. A 71-year-old man was diagnosed as having a polypoid mass within the gallbladder when he underwent right nephrectomy for a renal cell carcinoma. A preoperative diagnosis of simultaneous carcinoma of the gallbladder was made, and extended cholecystectomy with regional lymphadenectomy was performed five months after the initial operation. Postoperative histological examination of the polypoid mass within the gallbladder and a pancreatic mass excised during the second surgery revealed these resected tumors to be identical to the clear cell type of renal cell carcinoma. We feel that this case presents synchronous involvement of the gallbladder and pancreas by metastatic renal cell carcinoma of the right kidney.