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Biomedical subjects

T Kuroda

Publications and source records attributed to T Kuroda.

At least 73 records · Page 4Linked to original sources
PubMed2001

Two-dimensional changes in soft tissue profile following surgical mandibular advancement in Japanese retrognathic adults.

The purpose of this study was to evaluate changes in the hard and soft tissues and to test a preliminary method for predicting the soft tissue profile changes in 14 Japanese retrognathic patients who underwent surgical mandibular advancement. A pair of pre- and postoperative lateral cephalograms was taken for each subject. A paired t test identified significant hard and soft tissue changes following surgery. A Pearson correlation analysis was used to identify soft tissue changes for hard tissue changes in the horizontal and vertical dimensions. Multiple regression models were generated to predict postoperative variables based on preoperative variables. Significant changes in the hard and soft tissues were found in the area inferior to the point Stomion in both the horizontal and vertical dimensions. The soft tissue changes demonstrated a significant correlation not only with the corresponding hard tissue, but also with noncorresponding anatomical points. Moreover, the tendency of changes in the soft tissue was different in the lower lip area from the chin area in both the horizontal and vertical dimensions. Significant R2 and higher contribution ratio were obtained from the multiple regression analysis for the chin area compared to the lower lip area.

Adult↗
PubMed2000

Supine cephalometric study on sleep-related changes in upper-airway structures in normal subjects.

The purpose of this study was to examine sleep-related changes in the upper airway and surrounding structures including the mandible, hyoid bone, and cervical vertebra in normal subjects using lateral cephalograms in the supine position. Eleven male and nine female healthy adults participated in this study. Supine cephalograms were taken at end-expiration during wakefulness and in stage 1-2 non-rapid-eye-movement (NREM) sleep judged from the electroencephalogram and respiratory monitoring. A paired t-test was used to compare differences between the values measured during wakefulness and sleep. A significant increase in the amount of jaw opening was observed during sleep. The anteroposterior width of the upper airway was significantly decreased during sleep. The distances between the hyoid bone and the mandibular symphysis and between the cervical vertebra and the hyoid bone were significantly decreased during sleep. Consequently, the distance between the cervical vertebra and the mandibular symphysis was significantly decreased. These results suggest that the upper-airway dimension is significantly decreased and relatively small structural changes are induced during sleep in normal subjects.

Adult↗
PubMed2000

Execution of apoptosis signal-regulating kinase 1 (ASK1)-induced apoptosis by the mitochondria-dependent caspase activation.

ASK1 activates JNK and p38 mitogen-activated protein kinases and constitutes a pivotal signaling pathway in cytokine- and stress-induced apoptosis. However, little is known about the mechanism of how ASK1 executes apoptosis. Here we investigated the roles of caspases and mitochondria in ASK1-induced apoptosis. We found that benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (zVAD-fmk), a broad-spectrum caspase inhibitor, mostly inhibited ASK1-induced cell death, suggesting that caspases are required for ASK1-induced apoptosis. Overexpression of ASK1DeltaN, a constitutively active mutant of ASK1, induced cytochrome c release from mitochondria and activation of caspase-9 and caspase-3 but not of caspase-8-like proteases. Consistently, caspase-8-deficient (Casp8 (-/-)) cells were sensitive to ASK1-induced caspase-3 activation and apoptosis, suggesting that caspase-8 is dispensable for ASK1-induced apoptosis, whereas ASK1 failed to activate caspase-3 in caspase-9-dificient (Casp9 (-/-)) cells. Moreover, mitochondrial cytochrome c release, which was not inhibited by zVAD-fmk, preceded the onset of caspase-3 activation and cell death induced by ASK1. ASK1 thus appears to execute apoptosis mainly by the mitochondria-dependent caspase activation.

Amino Acid Chloromethyl Ketones↗
PubMed2000

Effect of mental stress on left ventricular ejection fraction and its relationship to the severity of coronary artery disease.

To evaluate the relationship between the mental stress-induced decrease in left ventricular ejection fraction (LVEF) and the severity of exercise-induced ischaemia, 20 patients with stable coronary artery disease (CAD) underwent radionuclide ventriculography during mental stress testing and stress myocardial perfusion single-photon emission tomography (SPET). We also examined whether changes in haemodynamic and neurohormonal parameters are related to changes in LVEF during mental stress. The LVEF decreased from 54.8% +/- 17.7% to 49.8% +/- 16.2% with mental stress (P < 0.0005). Ten of the 20 patients (50.0%) had a > or = 5% decrease in LVEF The remaining ten patients had no or a <5% decrease in LVEF There was a significant correlation between the change in LVEF during mental stress and the size of the reversible defect on stress myocardial perfusion SPET (r = -0.80, P < 0.0005), with close regional correspondence (75% identical). This correlation was less strong in the 12 patients with a total defect score at rest of <10 (r = -0.69, P = 0.014) than in the eight patients with a total defect score at rest of > or = 10 (r = -0.94, P = 0.001). The changes in blood pressure and heart rate were not significantly correlated with the change in LVEF, but the percent change in adrenaline concentration correlated with the change in LVEE It is suggested that mental stress impairs systolic function by inducing transient myocardial ischaemia. The effect of neurohormonal responses during mental stress on LV systolic function may also be important in patients with CAD.

Aged↗
PubMed2000

Mandibular deformities in parathyroid hormone-related protein (PTHrP) deficient mice: possible involvement of masseter muscle.

Previous studies using parathyroid hormone-related protein (PTHrP) null mutant mice have indicated severe abnormalities in the endochondral ossification, suggesting that PTHrP affects chondrocyte differentiation. In this study, we found in newborn PTHrP-deficient mice some deformities in the mandible that is formed via intramembranous ossification. The mandibular ramus was bent downwards and a prominent bone crest to which the deep layer of masseter muscle was tendinously attached was observed in the mandibular body. Transmission electron microscopic studies showed that active bone formation was progressing along the tendon fibers of the masseter muscle. The examination of 3-D reconstruction models indicated that the mandibular ramus was bent at the site of muscle attachment, which was shifted in the direction of the muscle fibers. Muscle fiber type analysis using myosin ATPase staining showed that the masseter muscle in the newborn PTHrP-deficient mice contained numerous type 2B fibers, demonstrating premature maturation of this muscle. Based on these findings, we speculated that premature maturation of the masseter muscle leads, probably due to increased tensile forces, to accelerated bone crest formation and subsequent bending of the mandibular ramus. These results further suggest that PTHrP is involved in the regulation of muscle development in normal animals.

Animals↗
PubMed2000

Gastric carcinoma presenting with extensive extraluminal growth: report of a case.

We report a 48-year-old-man with gastric carcinoma presenting with an unusual extraluminal growth. The patient underwent a barium meal examination and gastrofiberscopy because of progressive anemia over 6 months. These examinations revealed a Borrmann type 3 advanced gastric carcinoma of the greater curvature of the antrum. Biopsies showed moderately differentiated tubular adenocarcinoma. The intraoperative findings showed gastric carcinoma associated with extensive extraluminal invasion into the adjacent organs, i.e., the transverse colon and mesocolon. A palliative distal gastrectomy with a partial resection of the transverse colon was performed because of peritoneal dissemination found in the mesocolon and rectovesical pouch. A histological examination of the specimen confirmed adenocarcinoma which had massively infiltrated the transverse colon and mesocolon. His postoperative course was uneventful. However, he died of peritonitis carcinomatosa 9 months later.

Adenocarcinoma↗
PubMed2000

Nucleotide sequence and synthesis of infectious RNA from cloned cDNA of broad bean wilt virus 2 RNA 2*.

The complete nucleotide sequence of broad bean wilt virus -2 (BBWV-2) RNA 2 was determined. The sequence is 3593 nucleotides in length, and contains a single open reading frame which has the potential to encode a 119 kDa polyprotein. Direct amino acid sequencing of the virus coat proteins suggests that the polyprotein is processed to produce three proteins, 52 kDa, 44 kDa and 22 kDa in size. A comparison of several fabaviruses in terms of nucleotide sequence and amino acid sequences showed that BBWV-2 isolates display high sequence identity. A full-length cDNA constructed under the control of the T7 promoter could be successfully transcribed to produce biologically active RNA. This is the first report on generating infectious transcripts of BBWV-2 RNA 2.

Base Sequence↗
PubMed2000

Rapid serum vancomycin assay by high-performance liquid chromatography using a semipermeable surface packing material column.

A new isocratic high-performance liquid chromatographic (HPLC) assay has been developed for vancomycin that uses direct injection of microquantities of serum into a separation column filled with octyl-C(8) silica support that has a semipermeable surface. A mixture of disodium hydrogen phosphate buffer (pH 7.0) and acetonitrile is used as the mobile phase, and vancomycin is directly detected at 240 nm. The minimum limit of detection was 0.5 microg/ml at a signal-to-noise ratio of 3:1. Linearity was established from 0 to 100 microg/ml. The coefficient of variation for within-run reproducibility was 1.1-2.7% for a concentration range of 2.9-52.5 microg/ml; for day-to-day reproducibility it was 4.0% and 3.1% for a concentration range of 5.8-26.4 microg/ml, and the recovery rate was 94-105%. There was no interference from 41 antibiotics or other drugs currently in use. The correlation coefficient between the fluorescence polarization immunoassay (x) and this method (y) was 0.995 with a linear equation, y = 1.06x - 0.924. This method is simple, rapid, and provides an economical quantification of serum vancomycin.

Anti-Bacterial Agents↗
PubMed2000

Functional divergence of human genioglossus motor units with respiratory-related activity.

The genioglossus muscle has at least two types of motor unit with respiratory-related activity. Inspiratory motor units show phasic activity during inspiration, whereas inspiratory/expiratory motor units show phasic inspiratory activity superimposed on tonic activity. The purpose of this study was to investigate the physiological roles of these different genioglossus motor units. The unitary activities of 12 inspiratory and 12 inspiratory/expiratory motor units were recorded using fine-wire electrodes during quiet nasal breathing in eight normal adult males. The mean interspike interval and the SD of successive spikes were calculated for inspiratory and inspiratory/expiratory motor units, respectively. Scattergrams of the mean interspike interval versus SD were constructed for the two groups of motor units. The effects of changes in head position on the firing activity and the patterns of distribution of the mean interspike interval versus its SD were significantly different for inspiratory and inspiratory/expiratory motor units. These results suggest that the inspiratory and inspiratory/expiratory motor units have different functional roles in respiration; inspiratory motor units may be phasically active to counteract intraluminal negative pressure during inspiration, whereas inspiratory/expiratory motor units may be tonically active to maintain tongue posture.

Action Potentials↗
PubMed2000

Respiratory-related genioglossus electromyographic activity in response to head rotation and changes in body position.

The purpose of this study was to assess the effect of changes in body and head positions on respiratory-related activity of the genioglossus muscle in normal subjects in 8 body and head positions: (1) upright body with head straight, (2) upright body with head rotated to the right, (3) upright body with head rotated to the left, (4) supine body with head straight, (5) supine body with head rotated to the right, (6) supine body with head rotated to the left, (7) lateral recumbent body to the right, and (8) lateral recumbent body to the left. Phasic activity of the genioglossus muscle decreased significantly when subjects rotated their heads and moved from the supine to the lateral recumbent position. It is therefore concluded that genioglossus muscle activity is modulated in response to head rotation and changes in body position.

Adult↗
PubMed2000

Neuromuscular and skeletal adaptations following mandibular forward positioning induced by the Herbst appliance.

The purpose of this study was to examine neuromuscular and skeletal adaptations to changes in sagittal jaw relationships induced by the Herbst appliance. Six patients (age, 9 years and 5 months to 11 years and 2 months) with Angle Class II, division 1 malocclusions were studied longitudinally. The structural changes were determined by analyzing serial lateral cephalograms. Electromyographic recordings of specific masticatory muscles were used to evaluate neuromuscular adaptations. Similar cephalometric changes were observed in all patients. In all patients, lateral pterygoid muscle activity increased immediately after insertion of the appliance, but the activity decreased markedly after 4 to 6 months of treatment. In 4 of the 6 patients studied, however, the condyles were located in a slightly more downward and forward position. These findings indicate that the adaptation of muscular function occurs within a relatively short period and precedes the compensatory morphological changes produced through functional appliance therapy.

Adaptation, Physiological↗
PubMed2000

Genioglossus muscle activity during rhythmic open-close jaw movements.

The purpose of this study was to examine genioglossus muscle activity during rhythmic open-close jaw movements. The electromyographic activity of the genioglossus muscle was recorded with a bipolar fine-wire electrode in six healthy males. The electromyographic activities of the ipsilateral masseter and digastric muscles were simultaneously recorded with bipolar surface electrodes. The subjects were instructed to perform rhythmic open-close jaw movements in time with a metronome set at 23, 27, 33, 42 and 50 beats/min. In all of the subjects, rhythmic electromyographic activity of the genioglossus muscle was recorded in both the jaw-opening and jaw-closing phases. The activity of the genioglossus muscle was predominantly recorded in the jaw-opening phase in two subjects, and in the jaw-closing phase in two subjects. The burst duration of the electromyographic activity of the genioglossus muscle changed linearly in accordance with the cycle duration. However, the latency from the onset of the electromyographic activity of the masseter or digastric muscle to that of the genioglossus muscle was almost constant, independent of the cycle duration. Based on these findings, we conclude that the activity of the human genioglossus muscle is closely linked to that of masticatory muscles under the control of a closely related central pattern generator.

Adult↗
PubMed2000

Blunt thoracic and abdominal vascular trauma and organ injury caused by road traffic accident.

OBJECTIVES: To analyse the relationship between vascular trauma and associated injuries to intra-thoracic and abdominal organs caused by traffic accidents. Design retrospective study in a university hospital. MATERIALS AND METHODS: We investigated 458 consecutive patients who were admitted with blunt thoracic and/or abdominal trauma caused by road traffic accidents between 1986 and 1999. Vascular trauma was encountered in 54 patients (12%). RESULTS: The injured vessels were located in the abdomen in 45 patients and in the chest in nine patients. Mesenteric vessels were the most frequently injured vessels (33/45) in the abdomen, while the aorta and major vessels were most frequently injured (9/9) in the chest. Injury to the large/small intestine was often associated with mesenteric vessel injury (26/27). In the 190 patients with blunt abdominal organ injury, the frequency of mesenteric vessel injury was also highest, regardless of the injured organ. Vascular reconstruction was necessary only in one of 51 patients who underwent operation. CONCLUSIONS: Our results demonstrate that the mesenteric vessels are susceptible to blunt thoracic and abdominal trauma in road traffic accidents. Vascular reconstruction may be indicated for selected patients as long as the injuries to hollow organs are assessed carefully because of their strong association with vascular injury.

Abdomen↗
PubMed2000

Surgical treatment of neuroblastoma with micrometastasis.

BACKGROUND/PURPOSE: The aim of this study was to define the role of surgery in neuroblastoma with micrometastasis, which is detectable only by the polymerase chain reaction (PCR) method. METHODS: Fifty samples (peripheral blood 9, bone marrow 41) were harvested sequentially from 27 neuroblastoma patients, and the micrometastases were examined using the previously described single-step PCR method. The results were reviewed with the clinical courses. RESULTS: Radical surgery was performed in 9 patients with bone marrow micrometastasis. Event-free survival was obtained in 2 patients with stage IV disease (25.0%) for a follow-up period of 2 to 6 years in this group. Both patients received intraoperative radiation and subsequent autologous bone marrow transplantation (ABMT) using purged marrow. Radical surgery was performed in 18 patients without micrometastasis, and 6 of 9 advanced patients (66.7%) survived without the disease including 4 patients who received unpurged stem cell transplantation. CONCLUSIONS: Persistent micrometastasis in bone marrow should be considered predictive as a poor prognostic factor in neuroblastoma. Intensive local control with surgery and radiation is important for the patients with micrometastasis and should be followed by ABMT using purged marrow. Unpurged marrow may be safely used if the single-step PCR detects no micrometastasis.

Adrenal Gland Neoplasms↗
PubMed2000

Effective treatment plan for maxillary protraction: is the bone age useful to determine the treatment plan?

A major skeletal effect of reverse-pull headgear is a forward movement of maxilla, via remodeling of the circummaxillary sutures. We hypothesized that an evaluation of bone age would help to determine the effective planning and optimum timing using reverse-pull headgear. Differences in the cephalometric measurements between the initiation of treatment and after 1 year of treatment were calculated from 60 Japanese patients in mixed dentition with skeletal Class III malocclusions. Bone age was appraised by the Tanner-Whitehouse 2 method using hand-wrist radiographs at the initiation of treatment. The control groups (mean chronologic age, male 10.3 years and female 9.6 years) were treated by lingual arch and/or chincup, and the reverse-pull headgear groups (mean chronologic age, male 9.7 years and female 9.4 years) by reverse-pull headgear. The forward movement of the maxilla and increase in the palatal length were larger in the bone age-based younger male reverse-pull headgear subgroup than in the bone age-based older male reverse-pull headgear subgroup. The increase of SNA in the male reverse-pull headgear group was significantly larger than that of the female reverse-pull headgear group, which had a more mature skeletal status than the former. In the male reverse-pull headgear group, the forward movement of the maxilla and increase in the palatal length showed significant inverse correlation with the bone age, but not with the chronologic age. These results support our hypothesis that the bone age is a useful clinical indicator to determine the effective treatment plan with reverse-pull headgear.

Adolescent↗
PubMed2000

Elevated transferrin concentration in cerebral spinal fluid after subarachnoid hemorrhage.

Calcium-elevating protein cross-reacted with anti-human transferrin (TF) was purified in cerebrospinal fluid (CSF) after subarachnoid hemorrhage (SAH). The concentration of TF in CSF after SAH was measured, and the effects of TF on cultured smooth muscle cells (SMCs) were evaluated in order to understand the relationship between TF and cerebral vasospasm. Cisternal CSF samples were collected from 12 patients (seven men and 13 women) with SAH due to the rupture of a cerebral aneurysm, and eight control subjects. The patients were divided into two groups: (1) those presenting no clinical and radiological evidence of vasospasm (the non-vasospasm group; three men and 10 women, mean age 54.7 years), and (2) those presenting evidence of vasospasm (the vasospasm group; four men and three women, mean age 58.3 years). The concentration of TF in CSF was measured using Speriol micro-transferrin measure assay method. Nitrite accumulation in the culture media of SMCs incubated with TF was determined by diazotization method. The mRNA levels of inducible isoform of NOS (iNOS) in SMC incubated with TF were measured by the reverse transcription-coupled polymerase chain reaction method. Levels of TF were markedly different in the SAH and the control subjects. In the control group, all subjects had no detectable quantity of TF. In contrast, all patients after SAH had quantifiable TF in their CSF. Moreover, there was a significant difference between the vasospasm group and the non-vasospasm group in TF levels (p < 0.05). In the vasospasm group, the average value was 10.43 +/- 2.8 mg dl-1. In the non-vasospasm group, the average was 3.69 +/- 0.31 mg dl-1. The nitrite content in the culture medium incubated with TF was three times the content of control. TF also induced iNOS mRNA in SMC. This study demonstrated that an elevation of TF concentration in CSF after SAH was detected and iNOS mRNA in SMCs was also induced by TF. This may be involved in some roles of the development of the pathological series of events after SAH, including vasospasm.

Adult↗
PubMed2000

Effect of wearing cervical headgear on tongue pressure.

The purpose of this study was to examine whether wearing cervical headgear affected tongue pressure on the lingual surface of mandibular incisors, with particular attention to suprahyoid muscle activity. Tongue pressure was recorded using a miniature pressure sensor without cervical headgear and with two cervical headgears with traction forces of 500 and 1200 g, respectively. Electromyographic activity of suprahyoid muscles and respiratory-related movement were recorded simultaneously. Wearing cervical headgear significantly affected tongue pressure and suprahyoid muscle activity in the short-term. A significant increase in tongue pressure was observed in association with an increase in traction force from 500 to 1200 g, whereas no significant difference in suprahyoid muscles activity was seen between these force levels. These results suggest that wearing cervical headgear increases tongue pressure on the lingual surface of mandibular incisors, and this increase in tongue pressure may result from changes in the electromyographic activity of suprahyoid muscles to maintain adequate pharyngeal patency.

Adaptation, Physiological↗