Biomedical subjects

R Hayashi

Publications and source records attributed to R Hayashi.

At least 19 recordsLinked to original sources

PubMed2004

Identification of gammadeltaT lymphocytes in human periapical lesions.

Endodontic (root canal) therapy is required when the pulp of a tooth becomes necrotic due to a bacterial infection or trauma. A proportion of patients who receive endodontic therapy subsequently have periapical (around the tooth root) lesions detected by radiolucency. Currently, there are no means to identify susceptible patients. Although tissue from periapical lesions has been described as inflammatory, inflammatory cell types and their functions have been poorly characterized. For example, T lymphocytes were identified using pan specific anti-CD3 mAb, which recognizes both alphabeta and gammadeltaT cells. Using the current model of gammadeltaT cells as immunoregulatory cells; gammadeltaT cells can mediate protective or destructive milieus. We postulated that patients who have a periapical lesion, as identified by radiographic bone loss, mount a gammadeltaT cell response. We collected specimens removed by surgery from both periapical lesions and other oral tissues, generated total RNA and performed reverse-transcriptase polymerase chain reaction to identify rearranged delta genes. Results were confirmed with semi-nested polymerase chain reaction. In addition, we demonstrate that these lesions contain a population of CD3+ cells that are alphabetaT cell receptor negative, implying that these cells are gammadeltaT cells. Here we show that 36/37 of periapical lesions and only 2/11 of other lesions contain gammadeltaT cells (P<0.0001). Vdelta2+ T cells were the most common subtype identified (30/36) in these samples. This is the first report in the literature of the presence of gammadeltaT cells in human periapical lesions.

Adult↗

PubMed2003

Handy measurement for tongue motion and coordination with laryngeal elevation at swallowing.

At the oral stage of swallowing, the tongue plays a major role and proper tongue performance is necessary to form the bolus and transfer it to the pharynx. For the present study we built a prototype device for safe and handy objective estimation of tongue motion and coordination with laryngeal elevation at swallowing. The device records tongue pressure by means of two strain gauge pressure transducers aligned 20 mm apart on a brass strap placed along the palatal midline. Laryngeal vibration is recorded with piezo-electric acceleration transducers. Time differences between pressure onset at the anterior and posterior transducers and the first spike from laryngeal vibration are measured. Ten healthy subjects were asked five times to swallow 5 mL of water. Pressure onset at the anterior transducer preceded posterior pressure by 294 +/- 164 ms. Given the distance between the transducers, the tongue contracted (squeezed) at a speed of 93 +/- 60 mm s(-1). Laryngeal vibration occurred 671 +/- 175 ms after the onset of anterior pressure. There was considerable variation in these parameters between subjects. Though the data is limited, the device successfully and easily revealed certain aspects of tongue motion and coordination with laryngeal elevation.

Adult↗

PubMed2003

Extract of vinegar "Kurosu" from unpolished rice inhibits the development of colonic aberrant crypt foci induced by azoxymethane.

The modifying effects of administrating an ethyl acetate extract of "Kurosu" (EK), a vinegar made from unpolished rice, on development of azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) were investigated in male F344 rats. We also assessed the effects of EK on proliferating cell nuclear antigen (PCNA) index in ACF, prostaglandin (PG) E2 expression in the colonic mucosa and activities of detoxifying enzymes of glutathione S-transferase (GST) and quinone reductase (QR) in the liver. To induce ACF, rats were given two weekly subcutaneous injections of AOM (20 mg/kg body wt). They also received drinking water containing 0, 0.05, 0.1 or 0.2% EK for 4 weeks, starting 1 week before the first dosing of AOM. AOM exposure produced 140 +/- 23 ACF/rat at the end of the study (week 4). EK administration dose-dependently inhibited ACF formation and inhibition by 0.2% EK was statistically significant (P < 0.002). Treatment with EK significantly lowered PCNA index in ACF and reduced PGE2 content in the colonic mucosa, while EK elevated liver GST and QR activities. These findings suggest that EK may be effective for inhibiting colonic ACF, through induction of liver GST and QR and possibly alteration of PGE2 production.

Acetic Acid↗

PubMed2002

Palinopsia and perilesional hyperperfusion following subcortical hemorrhage.

We report a patient who exhibited transient palinopsia and visual hallucinations. Disturbances initially included an auditory component and increasingly were localized to the left visual field. These events occurred during recovery from a right subcortical hematoma with left homonymous hemianopia. Single-photon emission computed tomography (SPECT) demonstrated extensive perilesional hyperperfusion involving parts of the right parietal, temporal, and occipital cortex. Perilesional hyperperfusion disappeared as the visual abnormalities diminished. We believe that excitatory neuronal activation in perilesional cortex during recovery contributed importantly to the transient abnormal perceptions.

Cerebral Hemorrhage↗

PubMed2002

Effect of short-term low-intensity exercise on insulin sensitivity, insulin secretion, and glucose and lipid metabolism in non-obese Japanese type 2 diabetic patients.

The aim of the present study was to investigate the effects of short-term physical exercise that did not change body mass on insulin sensitivity, insulin secretion, and glucose and lipid metabolism in 39 non-obese Japanese type 2 diabetic patients. Insulin sensitivity and insulin secretion were estimated with homeostasis model assessment insulin resistance (HOMA-IR) and HOMA-B-cell function proposed by Matthews et al., respectively. All patients were hospitalized and were engaged in low-intensity exercise that consisted of walking and dumbbell exercise for successive 7 days. There were no changes in hospital diet and the dose of any medications used throughout the study. Fasting glucose, insulin, and lipids were measured before and after exercise. After exercise, serum triglyceride levels significantly decreased, but no significant changes were observed in total and HDL cholesterol concentrations. Fasting glucose, insulin, and HOMA-IR levels significantly decreased after exercise, but HOMA-B-cell function did not change during the study. There was no significant difference between BMI levels before and after exercise. From these results, it can be concluded that short-term (7 days) low-intensity physical exercise combined with hospital diet reduces serum triglycerides, insulin resistance, and fasting glucose levels without affecting BMI in non-obese Japanese type 2 diabetic patients.

Adult↗

PubMed2002

Peripheral mechanisms in tremor after traumatic neck injury.

Tremor is a rare manifestation after neck injury, and its physiological mechanism has not been elucidated. We studied the effects of torque loading and ischaemic nerve block on coarse postural tremor in the right upper extremity, which had developed in association with a C7-C8 radiculopathy after traumatic neck injury in a 55 year old man. Loading reduced the tremor frequency from 6.1 Hz to 4.2 Hz with corresponding electromyography (EMG) bursts at the same frequencies as the tremor. Ischaemic nerve block also reduced the tremor frequency from 6.2 Hz to 2.8 Hz, and the time course of the frequency was not in parallel with that of the size of the maximal M wave. A significant reduction of the tremor frequency by loading and ischaemic nerve block indicates a mechanical reflex mechanism underlying the tremor, and association of synchronous EMG bursts suggests an increase in gain in the stretch reflex loop. The stretch reflex loop plays an important role in generation of oscillation in tremor after neck injury.

Cervical Vertebrae↗

PubMed2001

Cyclophosphamide plus topotecan in children with recurrent or refractory solid tumors: a Pediatric Oncology Group phase II study.

PURPOSE: To determine the response rate of the combination of cyclophosphamide and topotecan in pediatric patients with recurrent or refractory malignant solid tumors. PATIENTS AND METHODS: A total of 91 pediatric patients, 83 of whom were fully assessable for response and toxicity, received cyclophosphamide (250 mg/m2/dose) followed by topotecan (0.75 mg/m2/dose), each given as a 30-minute infusion daily for 5 days. All patients received filgrastim (5 mcg/kg) daily until the absolute neutrophil count (ANC) was > or = 1,500 microL after the time of the expected ANC nadir. RESULTS: A total of 307 treatment courses were given to the 83 fully assessable patients. Responses (complete response plus partial response) were seen in rhabdomyosarcoma (10 of 15 patients), Ewing's sarcoma (six of 17 patients), and neuroblastoma (six of 13 patients). Partial responses were seen in two of 18 patients with osteosarcoma and in one patient with a Sertoli-Leydig cell tumor. Twenty-three patients had either minor responses (n = 6) or stable disease (n = 17); the median number of courses administered to patients with partial or complete response was six (range, two to 13 courses), and the median administered to those with stable disease was three (range, one to 11 courses). The toxicity of the combination was limited principally to the hematopoietic system. Of 307 courses, 163 (53%) were associated with grade 3 or 4 neutropenia, 84 (27%) with grade 3 or 4 anemia, and 136 (44%) with grade 3 or 4 thrombocytopenia. Despite the severe myelosuppression, only 34 (11%) of 307 courses were associated with grade 3 or 4 infection. Nonhematopoietic toxicity of grades > or = 3 was rare and consisted of nausea and vomiting (two courses), perirectal mucositis (one course), transaminase elevation (one course), and hematuria (two courses). CONCLUSION: The combination of cyclophosphamide and topotecan is active in rhabdomyosarcoma, neuroblastoma, and Ewing's sarcoma. Stabilization of disease was seen in osteosarcoma, although objective responses were rare in this disease. The therapy can be given with acceptable hematopoietic toxicity with the use of filgrastim support.

Adolescent↗

PubMed2001

Elicitation of N400m in sentence comprehension due to lexical prosody incongruity.

The role of lexical prosody in the semantic integration of spoken sentences consisting of a quiz stem and an answer word was investigated analyzing the event-related magnetic response, N400m. Three conditions regarding the relations between the quiz and the answer word were prepared: pitch-accent violation, phonemic violation and no violation. Both the pitch-accent and phonemic violations elicited significant N400m without any significant differences in the peak latency and magnitude of the equivalent current dipoles, suggesting that the role of pitch-accent in semantic integration is equivalent to that of phonemes. However, the rate of violation detection and the successful N400m source estimation were lower for the pitch-accent violation than for the phonemic violation, suggesting differential neural processes for the phonemic and prosodic cues.

Adult↗

PubMed2001

Restoration of epithelial cell polarity in a colorectal cancer cell line by suppression of beta-catenin/T-cell factor 4-mediated gene transactivation.

Beta-catenin acts as a transcriptional coactivator by forming a complex with T-cell factor/lymphoid enhancer factor (TCF/LEF) DNA-binding proteins. Aberrant transactivation of a certain set of target genes by beta-catenin and TCF4 complexes has been implicated in familial and sporadic colorectal tumorigenesis. A colorectal cancer cell line, DLD-1, becomes irregularly multilayered, when maintained confluent for 2-3 weeks, and forms numerous dome-like polypoid foci piled-up over the surface of cell sheets. By the use of a strict tetracycline-regulation system, we found that the continuous suppression of beta-catenin/TCF4-mediated gene transactivation by dominant-negative TCF4B (deltaN30) reduced these piled-up foci and restored a simple monolayer of polarized columnar cells resembling normal intestinal epithelium. The restoration of epithelial cell polarity was evident in two ways: (a) the formation of microvilli over the apical surface; and (b) the distribution of a tight junction protein, ZO-1, to the lateral plasma membrane. Retroviral expression of stabilized beta-catenin (deltaN89) induced the formation of similar piled-up foci in untransformed IEC6 intestinal epithelial cells. Sulindac, a nonsteroidal antiinflammatory drug effective against colorectal tumorigenesis in familial adenomatous polyposis syndrome, suppressed the formation of foci. The loss of epithelial cell polarity may be a critical cellular event driving beta-catenin/TCF4-mediated intestinal tumorigenesis.

Adenocarcinoma↗

PubMed2001

Use of an autologous cortical bone graft sandwiched between two intervertebral spacers in posterior lumbar interbody fusion.

Various intervertebral spacers with or without posterior instrumentation use pedicle screw fixation in posterior lumbar interbody fusion (PLIF). Recently we harvested an autologous cortical bone graft from a spinous process by en bloc resection and inserted it between two intervertebral spacers during PLIF surgery. Due to better balance, this procedure provides greater mechanical strength, larger contact area, and better bilateral restoration of disc height than PLIF using intervertebral spacers only, and there is no need to take a bone graft from the iliac crest. This technique appears to result in effective spinal fusion in PLIF surgery.

Adult↗

PubMed2001

Characteristics of fetal heart rate tracings prior to uterine rupture.

OBJECTIVE: To identify the fetal heart rate patterns that occurred in a 2-h period of time preceding uterine rupture. METHODS: The fetal monitor strips and the medical records of patients with a confirmed diagnosis of uterine rupture were reviewed. These patients delivered at the University of Michigan Hospital from January 1, 1985 to December 31, 1999 and were >or =28 weeks gestational age. Asymptomatic uterine scar dehiscences were excluded. The weeks of gestation, the number of cesarean sections, the surgical findings, and the maternal complications were obtained from the review of the maternal records. The fetal monitor strips for the 2 h preceding the uterine rupture were analyzed, and the fetal heart rate patterns were classified. RESULTS: During the study period, there were 11 patients identified with uterine rupture. Seven of the 11 (64%) had operative or post-operative complications. There were no maternal deaths. Review of the eight fetal heart rate tracings available revealed 7/8 (87.5%) with recurrent late decelerations and 4/8 (50%) with terminal bradycardia. All four of the patients with fetal bradycardia were preceded by recurrent late decelerations (100%). CONCLUSIONS: The most common fetal heart rate abnormalities that occurred prior to uterine rupture were recurrent late decelerations and bradycardia. The appearance of recurrent late decelerations may be an early sign of impending uterine rupture.

Bradycardia↗

PubMed2001

Relation between changes in long-latency stretch reflexes and muscle stiffness in Parkinson's disease--comparison before and after unilateral pallidotomy.

OBJECTIVE: To study the effects of posteroventral pallidotomy on both the size of long-latency stretch reflex (LLR) and the muscle stiffness in the wrist flexor muscles. PATIENTS AND METHODS: Eleven consecutive patients (right-handed, 6 men and 5 women) underwent left-side microelectrode-guided pallidotomy. The LLR of the contralesional forearm was studied at baseline and 2-3 months after surgery while patients continued to take their optimal medical regimens ('on' period). Patients were instructed not to respond to the perturbation (passive mode) or to oppose the mechanical extensor perturbation (active mode). RESULTS: The stretch reflex evoked by extension perturbations of the wrist consisted of a short-latency reflex (M1) and an LLR (M2). Pallidotomy had no effects on the size of M1 components in both passive and active mode and on that of M2 component in the passive mode, however, it significantly reduced M2 component in the active mode (P<0.05). The inherent muscle stiffness over 60 ms period of mechanical stretch was not influenced by pallidotomy in any experimental condition (preoperative vs. postoperative or passive mode vs. active mode). The hand displacement following M2 component increased significantly after pallidotomy in both passive (P<0.005) and active mode (P<0.05). The inverted value of the displacement following M2 component correlated with the size of M2 component (r=0.60, P<0.001). CONCLUSIONS: Pallidotomy decreased the transcortical reflex gain, probably at cortical level, and consequently reduced muscle stiffness.

Adult↗

PubMed2001

Teratoid carcinosarcoma of the ovary with prominent neuroectodermal differentiation.

We present what we believe to be only the second report of ovarian teratoid carcinosarcoma. The patient, a 59-year-old woman, was admitted to hospital complaining of a pelvic mass and of abdominal fullness. Advanced ovarian cancer was diagnosed, and a tumorectomy was done. The tumor occupied the pelvis, and metastasis was found in the liver and spleen. The solid tumor was composed of chondrosarcoma, squamous cell carcinoma, adenocarcinoma and malignant neuroectodermal components, which contained ganglioneuroblastoma-like and medulloepithelioma-like areas. Immunohistochemically, the neuroectodermal cells were positive for both neural and epithelial markers. This ovarian tumor consisted of frankly malignant components, with prominent neuroectodermal elements mixed with epithelial and mesenchymal elements in an organoid fashion; a quite rare tumor.

Biomarkers, Tumor↗

PubMed2001

Deep circumflex iliac perforator flap with iliac crest for mandibular reconstruction.

The deep circumflex iliac myocutaneous perforator (DCIP) flap with iliac crest was used to reconstruct oromandibular defects in 10 patients. In seven of the patients a dominant perforator was found preoperatively using a Doppler flowmeter; in five of these seven patients a DCIP flap was successfully transferred. In two of the seven patients the dominant perforators were too narrow: one patient underwent a standard osteocutaneous flap transfer and one patient underwent a second flap transfer. In three patients no dominant perforator was found before or during surgery. The freedom of the DCIP flap from the harvested iliac crest facilitates correct positioning. However, to ensure that the DCIP flap can be safely elevated, the presence of perforators must be confirmed preoperatively. Even when a perforator has been identified, complicated dissection may be necessary. We stress the importance of a thorough knowledge of the anatomy of second flaps and of obtaining informed consent to use them.

Adult↗

PubMed2001

The PU.1 and NF-EM5 binding motifs in the Igkappa 3' enhancer are responsible for directing somatic hypermutations to the intrinsic hotspots in the transgenic Vkappa gene.

Somatic hypermutation is a key mechanism in generating Ig with higher affinities to antigen, a process known as affinity maturation. Using Igkappa transgenes, the 3' enhancer (kappaE3') has been shown to play an important role in introducing hypermutations. In order to identify the cis-acting elements that regulate hypermutagenesis, we have generated transgenic substrates containing mutations/deletions in the kappaE3' region. Here, we report that base substitutions in the kappaE3', either in the PU.1 or in the NF-EM5 binding motif, not only reduce the mutation rate but also disrupt the directed mutagenesis in the intrinsic hotspots of the Igkappa transgene.

3' Untranslated Regions↗

PubMed2001

Influence of postsurgical residual tumor volume on local control in radiotherapy for maxillary sinus cancer.

BACKGROUND: The aim was to study the influence of postsurgical gross residual tumor volume on local control of maxillary sinus cancer treated with radiotherapy combined with debulking surgery. METHODS: Forty-three patients who underwent combined surgery and radiotherapy (50-72 Gy, median 60 Gy) for squamous cell carcinoma of the maxillary sinus were reviewed. Gross residual tumor volume (GRTV) after surgery was measured on computed tomograms obtained during the radiotherapy planning. Patients were classified according to GRTV as follows: group AA, GRTV = 0 (microscopic residual, n = 2); group A, GRTV < 10 cm3 (n = 24); group B, 10-40 cm3 (n = 9); and group C, > or = 40 cm3 (n = 8). The relationship between local control and GRTV was analyzed using univariate and multivariate analysis. RESULTS: The 2-year local control rate for all patients was 62%. The differences in local control rates between groups AA, A and B were not significant (P > 0.05), but the rate was significantly lower in group C than in the other groups (69% at 2 years vs 31% at 1 year, P < 0.001). Multivariate analysis showed that GRTV (P = 0.002) and histological differentiation (poorly differentiated histology was favorable, P = 0.035) were independent prognostic factors and that intra-arterial chemotherapy and administered total dose were not. Local control in groups A and B significantly depended on the total dose of radiotherapy, with 2-year control rates of patients receiving 50 Gy (n = 6) and > or = 60 Gy (n = 27) of 17% vs 79%, respectively (P < 0.001). CONCLUSIONS: Our data suggest that adequate, not complete, debulking associated with a total radiotherapy dose of > or = 60 Gy can provide satisfactory local control for patients with squamous cell carcinoma of the maxillary sinus.

Carcinoma, Squamous Cell↗

PubMed2001

Structural and functional changes in bovine pancreatic ribonuclease a by the replacement of Phe120 with other hydrophobic residues.

To clarify the specific role of Phe120 in bovine pancreatic ribonuclease A (RNase A), changes in the thermal stability and activity of F120L, F120A, F120G, and F120W were analyzed with respect to some thermodynamic terms, i.e., Gibbs free energy, enthalpy, and entropy. The structural destabilization of F120L, F120A, and F120G was due to a decrease in DeltaH(m) with a parallel decrease in amino-acid volume at position 120, while the destabilization of F120W can be ascribed to an increase in DeltaS(m) accompanying an increase in DeltaH(m), showing that the size of Phe120 produces an optimum balance of conformational enthalpy and entropy for achieving the maximal structural stability. Moreover, the replacement of Phe120 affects activity. The increase in K(m) showed that the hydrophobicity and pi electron of Phe120 are important factors in substrate binding. The decrease in k(cat) was predicted to be due to positional changes of the side chains of His12 and/or His119. The positional changes were successfully detected by the rate of carboxymethylation by iodoacetate or bromoacetate, which correlated very well with decreases in activity, supporting the view that Phe120 also plays an important role in determining the position of His12 and/or His119 in order to achieve efficient catalysis.

Acetates↗

PubMed2001

Ionizing radiation enhances matrix metalloproteinase-2 production in human lung epithelial cells.

Radiation pneumonitis is a major complication of radiation therapy. However, the detailed cellular mechanisms have not been clearly defined. Based on the recognition that basement membrane disruption occurs in acute lung injury and that matrix metalloproteinase (MMP)-2 can degrade type IV collagen, one of the major components of the basement membrane, we hypothesized that ionizing radiation would modulate MMP-2 production in human lung epithelial cells. To evaluate this, the modulation of MMP-2 with irradiation was investigated in normal human bronchial epithelial cells as well as in A549 cells. We measured the activity of MMP-2 in the conditioned medium with zymography and the MMP-2 mRNA level with RT-PCR. Both of these cells constitutively expressed 72-kDa gelatinolytic activity, corresponding to MMP-2, and exposure to radiation increased this activity. Consistent with the data of zymography, ionizing radiation increased the level of MMP-2 mRNA. This radiation-induced increase in MMP-2 expression was mediated via p53 because the p53 antisense oligonucleotide abolished the increase in MMP-2 activity as well as the accumulation of p53 after irradiation in A549 cells. These results indicate that MMP-2 expression by human lung epithelial cells is involved in radiation-induced lung injury.

Antisense Elements (Genetics)↗