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Biomedical subjects

K Uehara

Publications and source records attributed to K Uehara.

At least 19 recordsLinked to original sources
PubMed2007

Clinicopathological significance of microscopic abscess formation at the invasive margin of advanced low rectal cancer.

BACKGROUND: The aim of this study was to evaluate the clinicopathological significance of microscopic abscess formation (MAF) at the invasive front of advanced low rectal cancer. METHODS: The clinicopathological features of 226 consecutive patients with low rectal cancer, who underwent curative resection between May 1997 and December 2002, were analysed. RESULTS: Fifty-seven (25.2 per cent) of the 226 tumours had MAF and 169 (74.8 per cent) did not. Patients with tumours showing MAF were more likely to have extended surgery than those without MAF: 47 versus 31.4 per cent respectively underwent non-sphincter-preserving surgery (P=0.029) and 82 versus 60.9 per cent underwent lateral lymph node dissection (P=0.003). The incidence of lymph node metastases was lower in patients with MAF (30 versus 53.3 per cent; P=0.002). Univariable analysis of disease-free survival revealed that depth of invasion (P<0.001), lymph node status (P<0.001), histological type (P=0.035), lymphatic invasion (P<0.001), venous invasion (P<0.001), perineural invasion (P<0.001), focal dedifferentiation (P<0.001) and MAF (P<0.001) were significant prognostic factors. Multivariable analysis showed that lymph node status (P<0.001), perineural invasion (P=0.002), venous invasion (P=0.033) and MAF (P=0.012) remained independent prognostic factors. CONCLUSION: MAF may reflect indolent tumour behaviour and a more favourable outcome in patients with advanced low rectal cancer.

Abscess↗
PubMed2006

Reduction of prolonged postoperative hospital stay after laparoscopic surgery for colorectal carcinoma.

BACKGROUND: In evaluating the quality of laparoscopic surgery (LS) for colorectal carcinoma, many previous reports have used median or range values to assess the length of postoperative hospital stay and to show the complication and conversion rates separately. However, with this method, it is impossible to assess the proportion of patients who required prolonged postoperative hospital stay because of perioperative morbidities. This study investigated the proportion of patients who benefited from LS as minimally invasive surgery by assessing the percentage of patients who required prolonged postoperative hospital stay because of major perioperative morbidities. METHODS: A review of 202 patients who underwent LS for colorectal carcinoma at the authors' hospital between January 2002 and December 2004 was performed. Short-term outcomes were compared among the patients who underwent LS in 2002, 2003, and 2004. RESULTS: No significant differences were observed in baseline characteristics among the groups, and all the procedures in this study were completed laparoscopically. There were no significant differences in the operative times and intraoperative blood losses among the groups. Most of the patients resumed liquid intake on postoperative day 1 and solid food on day 3. However, there was a significant difference in the rate of postoperative prolonged hospital stays by year of surgery. In 2004, 97.3% of the patients (72/74) undergoing LS could be discharged to home within 8 days postoperatively. Major complications occurred at a low rate of 1.4% (1/74) in 2004. Regarding the reasons for prolonged postoperative hospital stay, inappropriate judgment of the physician in charge, based primarily on requests from patients without medical necessity, disappeared in 2004. CONCLUSIONS: When LS is performed properly by specialists who have accumulated sufficient experience in both LS and conventional open surgery for colorectal carcinoma, up to 97% of patients undergoing LS can benefit from minimally invasive surgery.

Adult↗
PubMed2006

Immunohistochemical detection of ubiquitin-positive intracytoplasmic eosinophilic inclusion bodies in diffuse alveolar damage.

AIMS: To clarify the relationship between ubiquitin-positive pneumocytes and intracytoplasmic eosinophilic inclusion bodies (IB) in patients who died of diffuse alveolar damage (DAD). METHODS AND RESULTS: Eighteen patients with DAD were studied, in whom hyaline membranes were present in one or more out of five sections from each lobe of the lungs and 15 patients with no DAD. Light microscopy revealed hyaline membrane in over 25% of lobes from 18 patients with DAD. The cytoplasm of pneumocytes from six of 18 cases of DAD contained IB. Immunohistochemically, all IBs were characteristically positive for both ubiquitin (Ub) and cytokeratin KL-1. Cytoplasmic granules were also Ub+ in four cases of DAD without IB. IB+ or Ub+ pneumocytes were undetectable in non-DAD patients. We evaluated DAD severity based on hyaline membrane formation; the mean score in DAD with IB (3.60; n = 6) was significantly higher than that in Ub- (2.92; n = 8). Ub+ pneumocytes were found with or without IB among those cases with high DAD scores. CONCLUSIONS: These findings suggest that disordered proteolysis in the Ub-mediated proteasome system leads to the accumulation of abnormal ubiquitinated protein, which includes cytokeratin, in pneumocytes. This is the first report to suggest that Ub+ pneumocytes are associated with disease severity in patients with DAD.

Adolescent↗
PubMed2005

Observation of nonlinear coupling between small-poloidal wave-number potential fluctuations and turbulent potential fluctuations in Ohmically heated plasmas in the JFT-2M tokamak.

Two types of electrostatic modes with small-poloidal wave numbers (approximately 1 and 10-15 kHz) are observed in the edge region of Ohmically heated plasmas in the JFT-2M tokamak. The envelope of the higher frequency coherent mode is modulated at the frequency of the lower frequency mode. A bispectral analysis revealed that a significant nonlinear coupling among the two types of fluctuations and the broadband background turbulent potential fluctuations occurs inside the last closed magnetic flux surface, suggesting that a nonlinear process such as the parametric-modulational instability is involved.

Journal Article↗
PubMed2005

Site- and cell-type- specific induction of intestinal inducible nitric oxide synthase in a rat model of endotoxemia.

The intestine is one of the major organs that are involved in sepsis. The inducible isoform of nitric oxide synthase (iNOS) is known to play a critical role in the pathogenesis of septic tissue injury by generating excess amount of nitric oxide (NO) in response to cytokines and endotoxin. In this study, we examined changes in gene expression of iNOS in various regions of the intestine as well as the distribution of iNOS protein in the intestinal cells in a rat model of endotoxemia produced by intraperitoneal injection of lipopolysaccharide (LPS; 10 mg/kg). While iNOS mRNA was undetectable in the intestine of untreated control animals, it underwent marked induction following LPS treatment. Induction of iNOS mRNA in the ileum was marked and biphasic, while it was also marked but monophasic in the jejunum. The induction of iNOS mRNA was maximal in the ileum. The administration of interleukin-6 (IL-6) upregulated intestinal iNOS gene expression specifically in the ileum. Consistent with enhanced iNOS gene expression, iNOS protein was markedly expressed in the ileum after LPS treatment, exclusively in the mucosal epithelium both at crypt and villus cells, although more prominently in the former. These findings suggested that intestinal iNOS expression was upregulated both at transcriptional and protein levels not only in a site-specific, but also in a cell type-specific manner in a rat model of endotoxemia, possibly through increasing serum IL-6 levels. Differential regulation of iNOS expression along the longitudinal and crypt-villus axes of the gut might be a determinant of the pattern of sepsis-induced intestinal damage.

Animals↗
PubMed2004

Impairment of gastrointestinal motility by nitrate administration: evaluation based on electrogastrographic changes and autonomic nerve activity.

BACKGROUND: Nitrates decrease the tone of the lower oesophageal sphincter, and may thus induce gastro-oesophageal reflux. AIM: In the present study, we evaluated electrogastrographic changes and heart-rate variability before and after the administration of nitrates. METHODS: In 15 patients with chest pain treated with nitrates, electrocardiography and percutaneous electrogastrography were performed before and after administration of nitrates. Autonomic nervous system function was evaluated by spectral analysis of heart-rate variability and serial changes in low frequency and high frequency power, and the low frequency/high frequency ratio were compared. Electrogastrograms were analysed by obtaining peak power amplitudes and their dominant frequencies. RESULTS: After the administration of nitrates (isosorbide dinitrate), high frequency power, an index of parasympathetic nervous activity, was significantly decreased, whereas the low frequency/high frequency ratio, an index of sympathetic nervous activity, was significantly increased. The mean peak amplitude of the electrogastrogram significantly increased postprandially both before and after treatment. After isosorbide dinitrate treatment, however, mean peak amplitudes after a meal were significantly lower than those obtained before treatment. The mean dominant frequency of the electrogastrogram did not vary before and after treatment. CONCLUSIONS: The present study suggests that nitrates inhibit gastrointestinal motility by decreasing autonomic nervous activity.

Aged↗
PubMed2004

Heat-stress enhances proliferative potential in rat soleus muscle.

The effects of heat-stress on proliferative potential in vivo were studied in rat skeletal muscle. Male Wistar rats (7-weeks-old) were divided into two groups: control (n=24) and heat-stressed (n=24). Rats in the experimental group were exposed to environmental heat-stress (41 degrees C for 60 min) in a heat chamber without anesthesia. The soleus muscles were dissected 1, 7, and 14 days after the heat exposure. The wet and dry weights of soleus muscle relative to body weight in the heat-stressed group were significantly higher than controls 7 days after the exposure (10.1% and 17.5%, respectively, p <0.05). The distribution of 5-bromo-2'-deoxyuridine and proliferating cell nuclear antigen-positive nuclei, that are the indicators for the cell proliferation, were increased by 2.2 and 5.1 times, respectively 1 day after heating (p <0.05). The expressions of heat shock protein 72 (58.0%) and phosphorylated p70S6 kinase (52.3%) were increased 1 day following heat exposure (p <0.05). These results suggest that heat-stress could promote the cell proliferation and induce muscular hypertrophy.

Adaptation, Physiological↗
PubMed2004

Heat stress facilitates the recovery of atrophied soleus muscle in rat.

Effects of heat stress on the recovery of atrophied soleus muscle were studied in rats. Ten-week-old male Wistar rats were randomly divided into cage control (CC) and 5-day hindlimb suspension group (HS). The half of the rats in group HS was exposed to heat stress (41 degrees C for 60 min) in an incubator immediately after the hindlimb suspension (HS-H) and the other group of rats was not heat stressed (HS-C) prior to 10 days of ambulation recovery. One group of cage control rats (CH) was also exposed to heat similarly. The soleus muscles were dissected at four time points, i.e., immediately after the suspension (or heat stress), and 3, 5, and 10 days after the recovery (n=8 per group at each time point). The absolute wet weight and water and protein content of whole soleus muscle in group HS-C were approximately 36, 27, and 8 mg less than CC (p <0.05). Thus, the percentage contribution of water and protein loss to the decrease in muscle weight was 75 and 22%, respectively. Although water content, as well as muscle weight, was elevated within 3 days, the increase of protein was delayed. Heat exposure prior to recovery accelerated the increase in protein content even in the control group. These phenomena were closely associated with 72-kD heat shock protein (HSP72) content. It is suggested that heat stress applied at the end of hindlimb unloading facilitated the recovery of atrophied soleus muscle of rat, through possibly HSP72-related events of protein metabolism. The data also indicated that the combination of heat and mechanical stress evoked larger and long lasting HSP72 response than does heat or mechanical stress alone.

Adaptation, Physiological↗
PubMed2004

[Management for type A acute dissection].

From March 1998 to May 2002, we experienced 46 patients with type A acute dissection (AAD). Fifteen patients managed initially with conservative treatment because of intramular hematoma (IH, n = 10), broad cerebral infarction (n = 3), others (n = 2). One who diagnosed IH at admission progressed to AAD and underwent surgery. However his diagnosis of IH at admission was proved to be misdiagnosis retrospectively. In 8 of the remaining 9 patients, hematoma disappeared during the follow-up of 6 months to 1 year. In patients with broad cerebral infarction, 2 died early after admission and 1 discharged with hemiplegia. Thirty-two patients underwent surgery and 1 with preoperative broad cerebral infarction died 36 days after surgery. In the remaining 31 patients, 30 patients discharged ambulatory.

Acute Disease↗
PubMed2003

Effects of heat stress and mechanical stretch on protein expression in cultured skeletal muscle cells.

Effects of heat stress, mechanical stretching or a combination of both on the expression of heat shock proteins (HSPs) and total protein level were studied in a culture system. Rat skeletal muscle cells (L6) were cultured on flexible-bottomed culture plates. They were subjected to one of the four following conditions: (1) 97 h incubation at 37 degrees C, (2) 1 h incubation at 41 degrees C followed by 96 h incubation at 37 degrees C, (3) 1 h incubation at 37 degrees C followed by 96 h cyclic stretching (18% of initial length, 2-s stretch and 4-s release) at 37 degrees C or (4) 1 h incubation at 41 degrees C followed by 96 h cyclic stretching at 37 degrees C. The expression of HSP72 and HSP90 and total protein was determined in the crude homogenates, supernatant and pellets. Cellular protein concentrations in the homogenates and pellets were increased by heat stress and/or mechanical stress (stretch). A cumulative effect of the combination of heating and stretch on the protein concentration in the homogenates and in the pellets was noted. The expressions of HSP72 and HSP90 in the pellets were also increased by heat stress and/or stretch. However, HSP90 in the supernatant did not change following heat stress and/or stretch. The regulation of HSP72 and HSP90 expression in skeletal muscle cells may be closely related to total protein, the abundance of which is also stimulated by mechanical and heat stresses. These observations suggest strongly that heating and passive stretch of muscle may be useful as a means of increasing muscle mass, not only in athletes but also in patients during rehabilitation.

Animals↗
PubMed2003

Site-selective nitrogen isotopic ratio measurement of nitrous oxide using 2 microm diode lasers.

We demonstrate a high-precision measurement of the isotopomer abundance ratio 14N(15)N(16)O/15N(14)N(16)O/14N(14)N(16)O (approximately 0.37/0.37/100) using three wavelength-modulated 2 microm diode lasers combined with a multipass cell which provides different optical pathlengths of 100 and 1 m to compensate the large abundance difference. A set of absorption lines for which the absorbances have almost the same temperature dependence are selected so that the effect of a change in gas temperature is minimized. The test experiment using pure nearly natural-abundance N(2)O samples showed that the site-selective 15N/14N ratios can be measured relative to a reference material with a precision of +/-3 x 10(-4) (+/-0.3 per thousand) in approximately 2 h.

Lasers↗
PubMed2002

Immunocytochemical observation of ghrelin-containing neurons in the rat arcuate nucleus.

Ghrelin is a novel peptide that stimulates the release of growth hormone from the pituitary and is involved in hypothalamic feeding regulation. A pre-embedding immunostaining technique was used to study the ultrastructure and synaptic relationships of ghrelin-containing neurons in the rat arcuate nucleus (ARC). Ghrelin-like immunoreactive (ghrelin-LI) neurons were found in the ARC, and were especially abundant in its ventral part. At the electron microscopic level, ghrelin-LI neurons received afferent synapses from many unknown axon terminals. Ghrelin-LI products in the immunoreactive cell bodies, processes, and axon terminals were detected mainly in dense granular vesicles about 110 nm in diameter. Ghrelin-LI presynaptic axon terminals often made synapses with unknown immunonegative neurons. These results suggest that ghrelin acts to regulate food intake through synaptic connections in hypothalamic neuronal networks.

Animals↗
PubMed2002

Reciprocal synaptic relationships between orexin- and melanin-concentrating hormone-containing neurons in the rat lateral hypothalamus: a novel circuit implicated in feeding regulation.

OBJECTIVE: Both orexin (ORX)- and melanin-concentrating hormone (MCH) are expressed in different neurons in the lateral hypothalamic area (LH), and are considered to have common effects on stimulating food intake. There are no reports to demonstrate neural interactions between them at the ultrastructural level. We observed these neurons in the LH to evaluate the relationships between them. DESIGN: We used two different types of double immunostaining to reveal the ultrastructure of both the ORX- and MCH-containing neurons. A preembedding double immunostaining technique was used to study the synaptic relationships between the two kinds of neuron. RESULTS: The main new findings are as follows: 1) Both ORX- and MCH-containing neurons received other synaptic input and made synaptic input to other neurons; 2) Reciprocal synaptic relationships were observed between the ORX- and MCH-containing neurons. CONCLUSION: The ORX- and MCH-containing neurons in the lateral hypothalamic area may influence food intake through synapse with each other.

Animals↗
PubMed2002

Anthropometry of the proximal tibia to design a total knee prosthesis for the Japanese population.

Anthropometric data on proximal tibiae of 100 knees in 80 Japanese patients undergoing total knee arthroplasty were obtained. Anterior-posterior (AP) and medial-lateral (ML) lengths of the tibia were measured on computed tomography scans and intraoperatively on tibial resection surfaces. A special small component is unnecessary, and size variation should focus on ML length of 65 to 75 mm because this includes 90% of women's knees. AP-to-ML ratio had a negative correlation with ML length, indicating that small knees were longer in the AP direction. Most prostheses had AP mismatch up to 5 mm for small women's knees. These data could provide the basis for designing the optimal tibial component for most of the Asian-Pacific population.

Aged↗
PubMed2002

Bone anatomy and rotational alignment in total knee arthroplasty.

The purpose of the current study was to investigate the bone anatomy in determining the rotational alignment in total knee arthroplasty using computed tomography. Axial images of 109 knees in 83 patients with varus osteoarthritis who had total knee arthroplasty were analyzed. On the images of the distal femur and the proximal tibia, a baseline for the anteroposterior axis of each component was drawn based on the epicondylar axis for the femur and the medial (1/3) of the tibial tuberosity for the tibia. The angle between these two lines was analyzed as the rotational mismatch between the components when they were aligned to the anatomic landmarks of each bone. Fifty-four knees (49.5%) had an angle of 5 degrees or greater and 13 knees (11.9%) had an angle of 10 degrees or greater. There was a tendency to align the tibial component in external rotation relative to the femoral component. The results indicated that the landmarks of each bone were the intrinsic cause of the rotational mismatch in knees with varus osteoarthritis. Surgeons doing total knee arthroplasties should be aware of this and check the rotational mismatch between the components. When it is present, the tibial component should be realigned to match the femoral component rotation to minimize problems caused by the mismatch.

Aged↗
PubMed2002

Cannulation of simple bone cysts.

We describe a consecutive series of 26 patients with simple bone cysts who were treated by curettage, multiple drilling and continuous decompression by the insertion of either a cannulated screw or a pin. In the first 15 patients we used titanium cannulated screws (group 1) and in the next 11 a cannulated hydroxyapatite pin (group 2). Satisfactory healing was achieved in 12 patients in group 1 (80%) and in all in group 2. This technique seems to be a promising option for the treatment of simple bone cysts. The cannulated hydroxyapatite pin is recommended because of its higher success rate and the fact that it does not need to be removed.

Adolescent↗