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Biomedical subjects

K Nishihara

Publications and source records attributed to K Nishihara.

At least 37 records · Page 2Linked to original sources
PubMed2000

Tubular carcinoma of the breast: a histologic subtype indicative of breast-conserving therapy.

We reviewed the clinical and pathologic features of pure tubular carcinoma of the breast with particular emphasis on the reported risk factors associated with local recurrences and survival following breast-conserving therapy. Of 1653 cases of invasive breast cancer, 12 (0.7%) were identified as pure tubular carcinoma. Clinical/pathologic features of pure tubular carcinoma were compared with those of T1 invasive carcinoma of all other histologic types (T1 IC). Of the 12 patients with pure tubular carcinoma (median tumor diameter 1.4 cm; range 0.5-3.0 cm), a multicentric association was identified in one patient while a multifocal association was seen in two. One patient had nodal metastatic disease out of the ten who underwent axillary dissection. No lymphatic vessel invasion was identified in any tumors (P < 0.1 vs T1 IC). In addition, extensive intraductal spread was not present in any tumors (P < 0.05 vs T1 IC). This study shows that patients with pure tubular carcinoma are appropriate candidates for breast-conserving therapy based on the clinical/ pathologic features. When a multifocal association is suspected preoperatively, either a wide local excision or a quadrantectomy which includes other lesions is thus recommended.

Adenocarcinoma↗
PubMed2000

Mothers' wakefulness at night in the post-partum period is related to their infants' circadian sleep-wake rhythm.

The relationship between a post-partum mother's wakefulness at night and her infant's circadian sleep-wake rhythm was examined. The subjects were seven primipara and their infants. Actigraphic recordings for the mothers and their infants were made over three to five continuous days during Weeks 3, 6, 9 and 12. A 24-h peak of autocorrelograms of the infants' movements appeared in two cases at Week 6, in six cases at Week 9, and in seven cases at Week 12. The mothers' night-time movements significantly decreased from Week 3 to Week 12. Mothers' wakefulness during night sleep in the post-partum period is related to their infants' obtaining circadian sleep-wake rhythm.

Adult↗
PubMed2000

Usefulness of early diastolic flow propagation velocity measured by color M-mode Doppler technique for the assessment of left ventricular diastolic function in patients with hypertrophic cardiomyopathy.

Flow propagation velocity (FPV) of left ventricular (LV) filling flow has been shown to be a useful index for the evaluation of LV diastolic function, which is relatively independent of preload in myocardial infarction and dilated cardiomyopathy, but the usefulness of FPV for hypertrophic cardiomyopathy (HCM) has not yet been determined. In 23 HCM patients and 26 control subjects, peak transmitral flow velocities in early diastole (E) and during atrial contraction (A), E/A ratio, deceleration time of E velocity, and isovolumic relaxation time were measured with the conventional Doppler technique, and FPV was measured from color M-mode Doppler images of LV filling flow. The time constant of LV isovolumic pressure decay (tau) was measured by a micro-manometer-tipped catheter in all HCM patients and 13 control subjects. Flow propagation velocity was significantly lower and deceleration time was significantly greater in HCM patients than in the control subjects, though no significant differences were observed in the other noninvasive indexes. Tau was significantly prolonged in HCM patients compared with that of control subjects (54+/-12 cm/s and 32 +/-7 cm/s, respectively; P<.0001). While the conventional indexes did not correlate with tau among the 36 patients in whom invasive studies were performed, FPV correlated well with tau (r = -0.76, P<.0001). Flow propagation velocity is a useful noninvasive index for the assessment of LV diastolic function in patients with HCM.

Adolescent↗
PubMed2000

Axillary lymph node metastases in patients with small carcinomas of the breast: is accurate prediction possible?

OBJECTIVES: To find out whether macroscopic classification of the tumour margin is predictive of axillary lymph node metastases and to identify a combination of clinical and pathological findings by which axillary node status can be predicted accurately in small carcinomas (T1) of the breast. DESIGN: Retrospective study. SETTING: Municipal referral centre, Japan. SUBJECTS: All 1003 patients with T1 invasive carcinoma of the breast who had axillary lymph node dissection between January 1970 and December 1996 as part of their treatment. MAIN OUTCOME MEASURES: The association between the incidence of axillary lymph node metastases and 10 clinical and pathological factors (age, palpability and size of tumour, macroscopic classification of tumour margin, clinical axillary status, radiating spiculation on a mammogram, histological type, lymphatic invasion, oestrogen and progesterone receptor status) were analysed. RESULTS: Clinical axillary node status, macroscopic classification of tumour margin, lymphatic invasion, and age of the patient were significant predictors of axillary lymph node metastases (p < 0.01 in each case). Among 47 patients aged 65 or more whose tumours had well-defined margins and with a clinical N0 status in the axillae, the incidence of histological axillary lymph node metastasis was only 6% (n = 3) whereas it was 65% in 57 patients with tumours of ill-defined margins whose axillae were N1 or N2. CONCLUSIONS: Macroscopic classification of tumour margins is an independent predictor of axillary lymph node metastases for patients with small carcinomas of the breast. However, even with combinations of the examined predictors of axillary node metastases, the subgroup of patients at minimal risk of metastasis was less than 5% in T1 breast cancer, whereas three-quarters of the patients had clear axillary lymph nodes. Most patients with T1 breast cancer will need surgical staging of the axillae by methods such as sentinel node biopsy.

Adult↗
PubMed2000

Parametric instabilities of intense lasers from interaction with relativistic hot plasmas

The stimulated Raman scattering (SRS) and relativistic modulational instability (RMI) of intense lasers in relativistic hot plasmas are studied, using the waterbag distribution in momentum space. Two cases are considered: a single hot electron distribution and a cold plasma attached with a hot electron tail. It is shown that both high temperatures and hot electron tails can significantly reduce the instability growth rates, shift the unstable regions in the wave-vector space, and change the Raman scattering frequency spectra from the cold plasma theory. In particular, at low-light intensities, there exists a cutoff thermal velocity beyond which SRS is completely suppressed. At high-light intensities, no clear cutoff thermal velocity is found owing to the merging of SRS with RMI.

Journal Article↗
PubMed2000

Generation of one-cycle laser pulses by use of high-amplitude plasma waves

The dynamics of a short laser pulse located in the density trough of a background plasma wave is investigated and a scheme is proposed to compress the pulse duration by use of a high-amplitude plasma wave. The threshold amplitude of the plasma wave, at which the compressing effect just balances the dispersive spreading of the laser pulse, is estimated for certain pulse profiles. Numerical simulations are conducted with particle-in-cell codes, where a pump pulse is used to generate a high-amplitude plasma wave and a signal pulse copropagates behind. It is shown that the signal pulse can be compressed by the plasma wave from ten laser cycles to about one cycle within a millimeter in tenuous plasma only a few percent of the critical density.

Journal Article↗
PubMed2000

High density collimated beams of relativistic ions produced by petawatt laser pulses in plasmas

Under optimal interaction conditions ions can be accelerated up to relativistic energies by a petawatt laser pulse in both underdense and overdense plasmas. Two-dimensional particle in cell simulations show that the laser pulse drills a channel through an underdense plasma slab due to relativistic self-focusing. Both ions and electrons are accelerated in the head region of the channel. However, ion acceleration is more effective at the end of the slab. Here electrons from the channel expand in vacuum and are followed by the ions dragged by the Coulomb force arising from charge separation. A similar mechanism of ion acceleration occurs when a superintense laser pulse interacts with a thin slab of overdense plasma and the pulse ponderomotive pressure moves all the electrons away from a finite-diameter spot.

Journal Article↗
PubMed2000

Overexpression of trigger factor prevents aggregation of recombinant proteins in Escherichia coli.

To examine the effects of overexpression of trigger factor (TF) on recombinant proteins produced in Escherichia coli, we constructed plasmids that permitted controlled expression of TF alone or together with the GroEL-GroES chaperones. The following three proteins that are prone to aggregation were tested as targets: mouse endostatin, human oxygen-regulated protein ORP150, and human lysozyme. The results revealed that TF overexpression had marked effects on the production of these proteins in soluble forms, presumably through facilitating correct folding. Whereas overexpression of TF alone was sufficient to prevent aggregation of endostatin, overexpression of TF together with GroEL-GroES was more effective for ORP150 and lysozyme, suggesting that TF and GroEL-GroES play synergistic roles in vivo. Although coexpression of the DnaK-DnaJ-GrpE chaperones was also effective for endostatin and ORP150, coexpression of TF and GroEL-GroES was more effective for lysozyme. These results attest to the usefulness of the present expression plasmids for improving protein production in E. coli.

Chaperonin 10↗
PubMed2000

Improvement of productivity of active horseradish peroxidase in Escherichia coli by coexpression of Dsb proteins.

Coexpression of two classes of folding accessory proteins, molecular chaperones and foldases, can be expected to improve the productivity of soluble and active recombinant proteins. In this study, horseradish peroxidase (HRP), which has four disulfide bonds, was selected as a model enzyme and overexpressed in Escherichia coli. The effects of coexpression of a series of folding accessory proteins (DnaK, DnaJ, GrpE, GroEL/ES, trigger factor (TF), DsbA, DsbB, DsbC, DsbD, and thioredoxin (Trx)) on the productivity of active HRP in E. coli were examined. Active HRP was produced by very mild induction with 1 microM isopropyl-beta-D-thiogalactopyranoside (IPTG) at 37 degrees C, whereas the amount of active HRP produced by the induction with 1 mM IPTG was negligibly small. Active HRP production was increased significantly by coexpression of DsbA-DsbB (DsbAB) or DsbC-DsbD (DsbCD), while coexpression of molecular chaperones did not improve active HRP production. The growth of E. coli cells was inhibited significantly by the induction with 1 mM IPTG in a HRP single expression system. In contrast, when HRP was coexpressed with DsbCD, the growth inhibition of E. coli was not observed. Therefore, coexpression of Dsb proteins improves both the cell growth and the productivity of HRP.

Journal Article↗
PubMed1999

Histopathological Predictors of Axillary Lymph Node Metastases in Patients with Breast Cancer.

BACKGROUND: A tumor 30 mm or less in diameter is a standard candidate for breast conserving surgery (BCS) in Japan. Axillary lymph node metastases (ALNM) is the most important prognostic factor for survival in patients with breast cancer, but the role of axillary node dissection has been controversial. Histopathological predictive factors of axillary lymph node involvement have not been established. The purpose of this study was to determine the association between the incidence of ALNM and histopathological factors by univariate and multivariate analysis METHODS: Sixty-five patients with noninvasive ductal carcinoma, and 993 patients with tumors 30 mm or less in diameter who underwent axillary dissection between 1988 and 1997 at our institute were reviewed. The association between ALNM and 13 histopathological factors (size, age, histological subtype, histological invasiveness, lymphatic invasion, vascular invasion, macroscopic classification, histological daughter mass, ductal spread, ER, PgR, p-53, and c-erbB-2) were analyzed by univariate and, when significant, by multivariate analysis. RESULTS: Only one patient with noninvasive ductal carcinoma had ALNM, and 33.1% of 993 patients with a tumor 30 mm or less in size had ALNM. Multivariate analysis identified six factors as independent predictors for ALNM: lymphatic invasion, size, histological invasiveness, macroscopic classification, age and histological daughter mass. CONCLUSION: Axillary lymph node dissection can be omitted in patients with noninvasive ductal carcinoma. Histopathological features of tumors 30 mm or less in diameter can be used to estimate the risk of ALNM, and routine axillary node dissection might be spared in selected patients at minimal risk of ALNM, if the treatment decision is not influenced by lymph node status, such as in elderly patients.

Journal Article↗
PubMed1999

Effect of itraconazole on the pharmacokinetics of digoxin in guinea pigs.

The effect of itraconazole (ITZ) on the pharmacokinetics of digoxin (DGX) was investigated in guinea pigs. The plasma concentrations of DGX in guinea pigs following treatment with ITZ (20 mg/kg intraperitoneally (i.p.)) after intravenous (i.v.) administration of DGX (0.125 mg/kg) were significantly higher than in the controls. The percentage cumulative excretion (6.9%) of DGX in bile of the ITZ-treated group up to 6 h after administration of DGX was significantly reduced (p < 0.05) compared with 10.5% in the control. The percentage cumulative excretion (3.1%) of DGX in urine of the ITZ-treated group up to 6 h after administration was also one third that in the controls. The total, biliary, renal and metabolic clearances for DGX in the ITZ-treated group were significantly reduced, while the V(dss) was unaffected. The plasma unbound fraction of DGX (ranged 47-58%) in the ITZ-treated group was generally similar to that in the controls (50-57%). The blood-to-plasma concentration ratio of DGX (range 1.28-1.42) in the absence of ITZ did not change in the presence of ITZ. Based on these results, the pharmacokinetic interaction between DGX and ITZ may be due not only to a reduction in the renal clearance but also to a reduction in the metabolic clearance of DGX by ITZ.

Animals↗
PubMed1999

Surgical approach to ossification of the thoracic yellow ligament.

BACKGROUND: Symptomatic ossification of the yellow ligament (OYL) at the lower thoracic level is uncommon. Although wide laminectomy has, until now, been the primary treatment for this disease, we propose a less invasive technique based on a new method of three-dimensional computed tomography (CT). METHODS: The clinical features and radiologic imaging findings of 37 patients with OYL (mean age, 54 years) were analyzed. The surgical approach was selected based on the position of the depicted OYL on 3D CT scan in each patient. RESULTS: The male-to-female ratio was 3:1. Involvement of the upper thoracic region was seen 11 times; of the middle region 8 times, and of the lower region 40 times (several patients had involvement in more than one region). About half of the patients complained of gait disturbance on admission caused by the markedly enlarged OYL. No postoperative complications were found. Neurologic deterioration was observed in only one patient. CONCLUSIONS: OYL should be treated as early as possible, using the least invasive technique available. By using 3D CT, we were able to perform limited surgery consisting of foraminotomy or extended partial laminectomy at the affected level after confirming the anatomic location of the OYL. In laterally extended OYL, it is necessary to decompress the radicular artery in order to prevent ischemic damage to the spinal cord.

Aged↗
PubMed1999

Analyses of mothers' sleep logs in postpartum periods.

In order to investigate mothers' sleep-wake patterns from five to 12 weeks in the postpartum period, we analyzed continuous sleep logs. Data for 341 days from seven mothers were analyzed for each postpartum week. There were significant differences in total sleep time and wake time at night. Wake time at night gradually decreased from the fifth to the twelfth week. These results from continuous sleep logs support the results of our previous polysomnographic findings based on intermittent measurements. A transition from interrupted sleep to noninterrupted sleep was observed from the ninth to twelfth week of postpartum. The mothers' sleep-wake patterns are discussed focusing on their relationships to the infants' sleep-wake patterns and feeding rhythm.

Adult↗
PubMed1999

Analysis of Helicobacter pylori binding site on HEp-2 cells and three cell lines from human gastric carcinoma.

Helicobacter pylori (H. pylori) is a pathogen responsible for chronic gastritis and peptic ulcer diseases. It colonises the gastric mucus layer and adheres to the gastric epithelial cell surface. As this adherence is the first step of infection, it is important to study the adherence mechanism. The aim of this study was to analyse the specific binding assay of H. pylori to HEp-2 cells and three gastric phenotype cell lines, AGS, MKN-45 and AZ-521. H. pylori NCTC 11637 grown on agar plates was harvested and used in experiments. H. pylori was inoculated to pre-cultured cell monolayers. Adhered bacteria were labelled with an anti-H. pylori antibody and an FITC-conjugated secondary antibody and quantified by using a fluorescent plate reader. Microbial adherence to HEp-2 cells increased with incubation time and incubated concentration of H. pylori. No further increase was obtained with four or more hours of incubation or with a concentration of 4 x 10(7) bacteria/well or more. Scatchard analysis revealed a linear plot and the Bmax value was 88.3. Similar adherence patterns were obtained when AGS, AZ-521 and MKN-45 cells were used for adherence assays, but they had a lower binding affinity than HEp-2 cells and AZ-521. MKN-45 cells had less receptors than HEp-2 and AGS cells. In conclusion, H. pylori adhered to the cell surface could be quantified by this assay method. H. pylori adhesion to cell surfaces has a single population of binding site and one type of binding site on HEp-2, AGS, AZ-521 and MKN-45 cells.

Adhesins, Bacterial↗
PubMed1999

[Theophylline].

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Bronchodilator Agents↗
PubMed1999

Laparoscopic distal pancreatectomy with preservation of the spleen.

We describe a case of chronic pancreatitis treated by laparoscopic distal pancreatectomy with conservation of the spleen involving the resection of the splenic vessels. A proximal ligation of the splenic artery and vein was performed, followed by transection of the body of the pancreas. Retroperitoneum was dissected to the left by mobilizing the stump of the transected pancreas. The entire distal pancreas was freed posteriorly. The distal splenic artery and vein were ligated and divided individually adjacent to the tail of the pancreas at the hilum of the spleen. The points of this operation were to ligate the splenic artery and vein at both sides of the resected pancreas and to save the spleen with the blood supply continuing through the short gastric vessels and the splenocolic ligament. This operation with splenic preservation is more suitable for a patient who is a candidate for laparoscopic distal pancreatectomy, which will minimize the operation time, preserve the useful immunologic role of the spleen, and obtain the intact resected specimen. Furthermore, this procedure is useful in chronic pancreatitis patients because it avoids the difficult dissection of the posterior pancreas off of the splenic vessels.

Aged↗