Search PubMed⌕ Search

Biomedical subjects

K Hayakawa

Publications and source records attributed to K Hayakawa.

At least 73 records · Page 4Linked to original sources
PubMed2000

Chromatographic methods for carcinogenic/mutagenic nitropolycyclic aromatic hydrocarbons.

Nitropolycyclic aromatic hydrocarbons (NPAHs), which are known to be carcinogenic and/or mutagenic, are considered to be one of the air pollutants that cause lung cancer. In the last two decades, a number of sensitive and selective methods have been developed for the determination of NPAHs and related compounds in environmental and biological samples. This paper describes the state of the art of the methods and applications.

Carcinogens↗
PubMed2000

Radiation therapy for elderly patient with squamous cell carcinoma of the uterine cervix.

OBJECTIVE: The purpose of this study was to profile cervical squamous cell carcinoma in elderly patients undergoing radiation therapy and to study the treatment outcome and side effects of therapy. MATERIALS AND METHODS: A retrospective analysis was carried out from the records of 380 patients with squamous cell carcinoma of the uterine cervix who had been given radiation therapy between 1970 and 1994. The patients were divided into three age groups: under 70 years (youngest group; n = 215), 70 to 79 years (intermediate group; n = 124), and 80 years or older (oldest group; n = 41). Radiation therapy was performed by a combination of external beam therapy and three brachytherapy fractions using low-dose-rate sources. RESULTS: The 5-year overall survival rates in the youngest, intermediate, and oldest groups were 58, 50, and 33%, respectively, while cause-specific survival rates were 68, 70, and 65%, respectively. For the patients with stage III, the 5-year overall survival rates in the youngest, intermediate, and oldest groups were 59, 48, and 36%, respectively, while cause-specific survival rates were 72, 70, and 70%, respectively. There was no statistical significance in the 5-year intrapelvic recurrence rates among the three groups. Grade 3 or 4 complications occurred in 6.5% of the youngest, 11.3% of the intermediate, and 7.3% of the oldest groups. CONCLUSION: Radiation therapy with external beam combined with three fractions of low-dose-rate brachytherapy proved both highly effective and safe for senior patients with cervical squamous cell carcinoma.

Adult↗
PubMed2000

Response by B cell precursors to pre-B receptor assembly: differences between fetal liver and bone marrow.

The expression of different sets of immunoglobulin specificities by fetal and adult B lymphocytes is a longstanding puzzle in immunology. In the past few years it has become clear that production of mu heavy chain and subsequent assembly with surrogate light chain to form the pre-B cell receptor complex is critical to promote development of adult B cell precursors in mouse bone marrow. Recently we found that instead of promoting pre-B cell expansion as in adult bone marrow, this complex inhibits pre-B cell growth in fetal liver, providing a previously unrecognized mechanism for alteration of the B cell repertoire with age. The consequence is very distinct primary repertoires for development of fetal B1 cells and adult bone marrow B2 cells.

Adult↗
PubMed2000

Radiologic spectrum of rectal stenosis.

Rectal stenosis is a common condition caused by a wide variety of diseases, including both intrinsic and extrinsic disorders, as well as both malignant and benign pathologies. Barium enema, CT, and MRI are the primary modalities for the evaluation of the disease, and careful observation of the characteristic radiologic features usually leads to correct diagnosis. However, some of the lesions looks very similar and are difficult to differentiate from each other. The purpose of this study is to review the literature on diseases that cause rectal stenosis, to clarify the characteristics of radiologic features, and to suggest the limitations in differential diagnosis. Deliberate analysis of these imaging features and correlation with clinical manifestations can facilitate a more specific diagnosis.

Diagnostic Imaging↗
PubMed2000

Muscarinic stimulation does not induce rhoA/ROCK-mediated Ca2+ sensitization of the contractile element in chicken gizzard smooth muscle.

We have attempted to determine whether muscarinic stimulation induces RhoA/ROCK-mediated Ca2+ sensitization of contractions in chicken gizzard smooth muscles. rhoA is a small GTP-binding protein, and ROCK is a rhoA-associated coiled coil-forming serine/threonine kinase. The relationship between the cytosolic Ca2+ level ([Ca2+]i) and muscle force in the presence of a high K+ concentration was not different from that in the presence of carbachol. Verapamil inhibited muscle force in proportion to the decrease in [Ca2+]i in both the muscle stimulated with high K+ and that stimulated with carbachol. In addition, Y-27632 (10 microM), a ROCKs inhibitor, had no effect on the contractions. In the alpha-toxin-permeabilized muscles, Ca2+ induced a greater contraction in the presence of guanosine 5'-O-(3-thiotriphosphapte) (GTP[gamma-S]), whereas carbachol with GTP was not effective. The GTP[gamma-S]-induced Ca2+ sensitization was completely inhibited by Clostridium botulinum exoenzyme C3. Western blot analysis revealed both rhoA and ROCKII in the muscle extract. In addition, reverse transcriptase polymerase chain reaction (RT-PCR) analysis revealed the expression of both ROCKI and ROCKII mRNAs. These results suggest that Ca2+ sensitization in the chicken gizzard is elicited via a rhoA/ROCKs pathway, and that this pathway may be responsible for the augmentation of contraction by GTP[gamma-S] in the permeabilized muscles. If such a pathway does exist, however, carbachol-induced contraction may not be coupled to it, which explains the absence of Ca2+ sensitization in the intact chicken gizzard stimulated by carbachol.

Amides↗
PubMed2000

Severe complications of mediastinal pancreatic pseudocyst: report of esophagobronchial fistula and hemothorax.

We report two patients with alcoholic pancreatic pseudocyst which communicated to the mediastinal space through the aortic hiatus, in one patient resulting in hypotensive shock due to hemothorax, and in the other, resulting in esophagobronchial fistula via the mediastinal cyst. The first patient was successfully treated by radical resection of the pancreatic body and tail, and the spleen, with an ultrasonic scalpel, although inflammatory changes caused by pancreatitis were so prominent that the splenic vein was occluded. The second patient could not be treated surgically, because the superior mesenteric vein had been occluded by chronic pancreatitis; he died of respiratory failure and sepsis due to aspiration pneumonia, despite receiving medical treatment.

Adult↗
PubMed2000

Three minute, but not one minute, ischemia and nicorandil have a preconditioning effect in patients with coronary artery disease.

OBJECTIVES: This study focused on 1) the determination of the optimal preconditioning (PC) duration, and 2) the protective effect of nicorandil (NC), a hybrid nitrate with a KATP channel opening effect, during a percutaneous transluminal coronary angioplasty (PTCA) model in humans. BACKGROUND: The ischemic PC effect is induced in 180 s ischemia, but not in 120 s ischemia in rabbit hearts. However, the duration of ischemia that induces PC effect and the role of the KATP channel in the PC effect in humans are still unclear. METHODS: Forty-six patients with stable angina were randomly allocated to four groups: the duration of the first inflation as PC ischemia was 60 s in the PC60 group (n = 12), and 180 s in the PC180 group (n = 12). In the other groups, NC (80 microg/kg) was intravenously given for 1 min in the NC group (n = 12), and isosorbide dinitrate (ISDN) (40 microg/kg) was given in the ISDN group (n = 10). Five minutes after first inflation or drug administration, a second inflation was conducted for 120 s in each group. In the ECG, the lead with the largest shift in ST segment (deltaST max), and the sum of elevated ST levels in all leads (sigmaST) were determined. RESULTS: In the PC60 group, no significant difference was observed in either deltaST max or sigmaST between the first and second inflation. However, the second inflation in the PC180 group showed significantly lower levels of deltaST max and sigmaST compared with those of the first inflation. In the NC group, both deltaST max and sigmaST measured at 30 s and 60 s after balloon inflation were significantly lower than those of the first inflation in the PC60 and PC180 control groups. In the ISDN group, no significant difference was observed in deltaST max or sigmaST. CONCLUSION: In human PTCA models, a PC effect is observed in 180 s ischemia, but not in 60 s ischemia. A pharmacological PC effect is induced by NC, a KATP channel opener with a nitrate-like effect but not ISDN. This suggests that the opening of KATP channels plays an important role in the protecting effect of NC.

Angina Pectoris↗
PubMed2000

Development and function of B-1 cells.

Results from immunoglobulin-transgenic mice and BCR-mutant mice have been widely interpreted in recent years as supporting a simple 'activation' model for the origin of CD5+/B-1 B cells. However cell transfer experiments over 10 years ago and recent work investigating pre-BCR signaling suggest striking differences between B cell development in fetal liver and adult bone marrow, lending support for a 'lineage' model that we favor. Recent progress has been made relating to the development and function of the CD5+/B-1 B cell subpopulation in mice; the data can be viewed in the context of the generation of this subpopulation by a distinctive fetal B cell developmental process.

Aging↗
PubMed2000

Expression of cofilin isoforms during development of mouse striated muscles.

Cofilin (CF) is an actin regulatory protein that plays a critical role in actin filament dynamics in a variety of cells. Two cofilin isoforms. muscle-type (M-CF) and nonmuscle-type (NM-CF) encoded by different genes, exist in mammals; in the adult, the former is predominantly expressed in muscle tissues, while the latter is distributed in various non-muscle tissues (Ono et al., 1994). In this study, we examined cofilin isoform expression during skeletal and cardiac muscle development in mice using cDNA probes and antibodies which distinguish the isoforms. We found that the expression of M-CF was initiated in terminally differentiated myogenic cells in both the myotome and limb buds. In myogenic cell cultures, its expression occurred coupled with myotube formation. NM-CF was expressed in developing skeletal and cardiac muscles but disappeared from skeletal muscle during postnatal development, while its expression persisted in the heart, even in adult mice. A similar situation was observed in the heart of other mammals. Thus, it is likely that the both cofilin isoforms are involved in the regulation of actin assembly during myofibrillogenesis. Only M-CF could be involved in actin dynamics in mature skeletal muscle, while both isoforms could be in the mature heart.

Actin Depolymerizing Factors↗
PubMed2000

Prostate cancer with multiple lung metastases in a hemodialysis patient.

In hemodialysis patients, few cases of prostate cancer have been reported until recently. We present a case of prostate cancer with multiple lung metastases in a chronic hemodialysis patient. A 65-year-old Japanese man who had maintained hemodialysis for 5 years was referred to our hospital with multiple metastatic lung tumors. Serum prostate tumor markers were highly elevated although his plasma testosterone level was within the normal range. A transrectal needle prostate biopsy confirmed a histologic diagnosis of moderately differentiated adenocarcinoma. Androgen blockade therapy was very effective as evidenced by a quick decrease of serum tumor markers. The follow-up computed tomography scan of the chest performed 3 months later showed a complete disappearance of the coin lesions. The early detection of prostate cancer in hemodialysis patients is difficult because of a lack of urologic symptoms, which indicate the importance of periodic screening by serum tumor markers. Combined androgen blockade is effective even in hemodialysis patients. However, close follow up is necessary because long-term results and prognoses are still unknown.

Adenocarcinoma↗
PubMed2000

Efficacy of temporal musculopericranial flap for reconstruction of the anterior base of the skull.

Since March 1988 the temporal musculopericranial (TMP) flap has been used as our flap of choice to reconstruct defects of the anterior base of the skull that are larger than 2 x 3 cm, including the dura mater, in 33 patients. The primary diseases were malignant head and neck tumours (n = 16), trauma (n = 15), meningioma (n = 1), and teratoma (n = 1). The dura mater was reconstructed with a unilateral TMP flap, after which the cranial and nasal cavities were closed with the opposite TMP flap. In addition, bone was grafted by sandwiching the bone between the two flaps and fixing it to the surrounding residual bone. When a large area was resected, making it impossible to use a TMP flap, a frontal musculopericranial (FMP) flap or a free flap (usually the rectus abdominis myocutaneous flap) was used to close the cranial and nasal cavities. Thirty of the 33 patients recovered with no postoperative complications. Two patients developed extradural abscesses in the anterior base of the skull and one developed mild meningitis, but they were successfully treated conservatively. When bilateral TMP flaps were used for the reconstruction, no patient had aesthetic problems in the forehead region. The TMP flap is extremely effective for the reconstruction of the anterior base of the skull because it is minimally invasive and causes few aesthetic problems in the forehead region.

Adolescent↗
PubMed2000

Anterior transvertebral herniotomy for cervical disk herniation.

This study analyzed the results of anterior transvertebral herniotomy for cervical disk herniation to assess the utility of this procedure. Anterior transvertebral herniotomy was performed in 24 patients who had cervical disk herniation without spinal canal stenosis. In most patients, a good result was obtained, but simultaneous or subsequent anterior intervertebral fusion was necessary in four patients. In one (4%) patient, the two adjacent vertebrae had fused spontaneously. The best indication for this treatment judging from the postoperative results is a large disk hernia associated with either myelopathy or radiculopathy, but without spinal canal stenosis.

Adult↗
PubMed2000

Skin hemodynamics during change from supine to lateral position.

The purpose of this study was to identify the skin hemodynamics during the position change from supine to lateral in patients with neurodegenerative diseases. The participants were 19 patients with neurodegenerative diseases and 12 healthy volunteers. The alteration in the total concentration of oxyhemoglobin and deoxyhemoglobin, indicative of change in blood volume, was measured in the skin of the left flank by using a portable noninvasive tissue oxygen monitor by near-infrared spectroscopy. The positions were changed from the left and right lateral with a return to the supine between each procedure. In healthy volunteers, total hemoglobin concentration (skin blood volume) increased when the position changed from supine to left lateral and decreased when changed from supine to right lateral. The decreased skin blood volume gradually recovered after a change from the supine to the right lateral position in healthy volunteers. However, it did not recover in three sporadic olivopontocerebellar atrophy (OPCA) patients with marked autonomic dysfunction and one Parkinsonian patient with severe orthostatic hypotension. Our study identified that the intracutaneous blood was changing dynamically during the position change from supine to lateral and was regulated by autonomic nerve function.

Autonomic Pathways↗
PubMed2000

Crystallization and preliminary X-ray diffraction studies of monomeric isocitrate dehydrogenase from corynrbacterium glutamicum. erratum

In the paper by Audette et al. [Acta Cryst. (1999), D55, 1584-1585] the postal code of one of the authors was printed incorrectly. The correct version is given above. Also the reaction catalyzed by isocitrate dehydrogenase was given incorrectly in the paper; the correct reaction is given below. Isocitrate + NADP(+) <--> Oxalosuccinate + NADPH. Oxalosuccinate <--> alpha-Ketoglutarate + CO(2).

Journal Article↗
PubMed2000

Collaborative work to evaluate toxicity on male reproductive organs by repeated dose studies in rats 17). Testicular toxicity of E7010, a sulfonamide tubulin polymerization inhibitor.

E7010 (N-[2-[(4-hydroxyphenyl)amino]-3-pyridinyl]-4-methoxybenzenesulfonamide), a sulfonamide antitumor agent that inhibits tubulin polymerization, was orally administered to male Slc:SD rats at doses of 50 and 75 mg/kg once a day for 2 weeks. E7010 at a dose of 75 mg/kg induced severe testicular lesions characterized by marked decrease and/or loss of seminiferous epithelial cells, which sometimes resulted in tubules with only Sertoli cells. In the 50 mg/kg group, alteration of germ cells was evident at various stages of spermatogenesis, and apoptotic figures of meiotic spermatocytes at stage XIV were frequently observed. Single dose treatment of 50 mg/kg was also performed and was revealed a decrease of round spermatids in stage VII at necropsy after 1 week. Thus the target cells were considered to be meiotic spermatocytes at stage XIV. The present study indicates that 2-weeks repeated dosing is sufficient to detect the testicular toxicity of E7010.

Administration, Oral↗
PubMed2000

Technetium tin colloid test detecting symptomless dysphagia and ACE inhibitor prevented occurrence of aspiration pneumonia.

Symptomless dysphagia and swallowing disorders play a very important role in the pathogenesis of aspiration pneumonia. A videofluoroscopic examination and a simple two-step swallowing provocation test (STS-SPT) could be useful for detection of swallowing disorders in elderly patients with stroke, however, there is no report on such a test for detection of symptomless dysphagia. We administered 1 ml Technetium Tin Colloid (99mTC) to the patient during sleep via a nasal catheter placed in the mouth. At 09:00 h the next day, symptomless dysphagia was checked for by imaging. Improvement of the symptomless dysphagia was observed, and thus we could prevent the occurrence of aspiration pneumonia. The 99mTC test was particularly useful in detecting symptomless dysphagia in elderly patients with stroke.

Aged↗