Biomedical subjects

K Hirata

Publications and source records attributed to K Hirata.

At least 415 records · Page 23Linked to original sources

PubMed1998

[Unilateral gustatory disturbance by pontine infarction].

We reported a case of pontine infarction presenting as diminished taste on the contralateral side. A 67-year-old man was hospitalized with a sudden onset of right hypogeusia. No neurological abnormalities were found except diminished taste in the areas innervated by the chorda tympani, greater petrosal and glossopharyngeal nerves on the right side. Brain MRI demonstrated a lesion with low-intensity on T1-weighted images and high-intensity on T2-weighted images in the left suprapontine tegmentum. Cases of pontine disease presenting as contralateral dysgeusia have rarely been reported. In the present case, we considered that infarction occurred superior to the pontine taste are (PTA). It is suggested that the gustatory pathway superior to PTA takes a chiasmal tract ascending in the brainstem.

Cerebral Infarction↗

PubMed1998

[Mechanism of the development of organ failure].

Multiple organ failure (MOF) is a critical condition developing in patients with overwhelming bodily injury resulting from major surgical insult, severe trauma, extensive burns, acute pancreatitis, and sepsis. It has recently become evident that the host response to such injury is the main pathogenetic factor contributing to the development of MOF. The proinflammatory cytokines tumor necrosis factor (TNF) and interleukin (IL)-1 are known to play a pivotal role in the pathogenetic mechanisms of MOF. In response to bodily injury, macrophages produce and release TNF and IL-1, which subsequently induce the production of other cytokines (IL-6, IL-8, etc.) and other endogenous chemical mediators. The resultant systemic inflammation may develop into MOF mainly through neutrophil-endothelial cell interaction when the primary injury is overwhelming or a second inflammatory insult such as sepsis triggers an exacerbated inflammation. It has recently been confirmed that the transcription factor NF-kappaB is involved in the up-regulation of a variety of proinflammatory genes and that cell-mediated immunity is down-regulated in the event of major bodily injury through a shift in the balance between T helper 1 (Th1) and Th2 cytokine response patterns. The molecular immunological mechanisms by which these factors participate in the development of MOF should be characterized.

Humans↗

PubMed1998

[Clinical application of multi-shot diffusion EPI in neurological disease].

Using the multi-shot EPI method we investigated the clinical application of diffusion weighted imaging (DWI) in the diagnosis of neurological disease. The multi-shot method provided better susceptibility artifact-free DWI than the single-shot method particularly in the region of the posterior cranial fossa. DWI using the multi-shot EPI method readily shows the pyramidal tract extending from the internal capsule to the brainstems which is inaccessible by the conventional single-shot EPI method, and providing three-dimensional and distinct images of pyramidal tract changes in amyotrophic lateral sclerosis or cerebral infarction with pyramidal tract disturbance. Our findings suggest that the use of DWI with the multi-shot EPI method would provide a technique for the easy diagnosis and evaluation of various neurological diseases.

Amyotrophic Lateral Sclerosis↗

PubMed1998

Quantitative reverse transcription-PCR assay of the RNA component of human telomerase using the TaqMan fluorogenic detection system.

We established the validity of a quantitative reverse transcription (RT)-PCR assay for the RNA component of human telomerase (hTR), using the TaqMan fluorogenic detection system. Using this assay, we quantified hTR expression in two human pancreatic cancer cell lines, ASPC-1 and MIAPaCa-2. Our results indicated that hTR expression in MIAPaCa-2 was 1.99-fold higher than that in ASPC-1 cells. This TaqMan RT-PCR assay appears to be useful in determining the amount of hTR in clinical specimens.

Cell Line↗

PubMed1998

[Relative valve area stenosis after replacement of a Starr-Edwards mitral valve (model 6520) for corrected TGA (S, L, L): report of a case].

The patient was a 38-year-old man who had undergone mitral valve replacement with a Starr-Edwards disc valve (model 6520, 3 M, phi 30 mm, functional valve area: 2.85 cm2) at the age of 15 years for TR combined with corrected TGA. He developed dyspnea on exertion and palpitations at the age of 30 years, and paroxysmal supraventricular tachycardia appeared at the age of 35 years. Cardiac catheterization revealed that the PCWP was 30 mmHg and the TVA was 1.1 cm2, and a diagnosis of stenosis of the prosthetic valve was made. Thus, replacement of the Starr-Edwards disc valve using a BICARBON double leaflet valve (phi 27 mm, functional valve area: 2.85 cm2) was performed. The operative findings of the Starr-Edwards disc valve revealed a normal appearance and no pannus growth. Postoperative echocardiography and cardiac catheterization found that the TVA was 3.7 cm2 and the PCWP was 13 mmHg. The actual valve area of the disc valve sewn on the ventrical, which was anatomically RV construction might have been smaller than the ideal area; however, the double leaflet valve proved efficient in our patient. This case report serves to demonstrate that because of the postoperative difference in measurement between the actual valve area and the prostheticin ball or disc valve, patients undergoing mitral valve replacement must be followed up carefully.

Adult↗

PubMed1998

[A case of Guillain-Barré syndrome associated with bilateral ballism: an overlap between Fisher's syndrome and Guillain-Barré syndrome].

A 29-year-old woman developed diplopia and ataxic gait. Neurological examination revealed total ophthalmoplegia, cerebellar ataxia, and areflexia. Muscle weakness in four limbs was also noted. We diagnosed the patient as having an overlap between Fisher's syndrome and Guillain-Barré syndrome. On day 5, she suddenly had flinging involuntary movements affecting the face and four extremities. Surface EMG recording revealed 1.5- 2 Hz rhythmic grouping discharges. The involuntary movements were considered as ballism. Brain CT and MRI could not detect any abnormal findings in subthalamic nucleus, but, electrophysiological findings revealed CNS lesions. Therefore, the clinical diagnosis also were Bickerstaff's brainstem encephalitis. She had high titer of IgG antibody to GQ 1b (1:64,000). Sera taken from patients with Fisher's syndrome, Guillain-Barré syndrome with ophthalmoparesis and Bickerstaff's brainstem encephalitis during the acute phases of these syndromes frequently have IgG antibody to GQ 1b ganglioside. It is concluded that some cases of acute ophthalmoparesis subsequent to infection or immunization may be categorized as autoimmune diseases. Hence, such disease which show external ophthalmoparesis may be designated the "anti-GQ 1 b IgG antibody syndrome". This is the first report on the patient with Guillain-Barré syndrome and the related disorders who showed ballism.

Adult↗

PubMed1998

[A case of polyneuropathy by microscopic polyarteritis nodosa].

We report a 59-year-old man with chronic sensorimotor polyneuropathy mimicking chronic inflammatory demyelinating polyneuropathy. Sural nerve biopsy revealed marked loss of myelinated fibers and myelin ovoid formation with vasculitis in the epineurium. Renal biopsy was performed subsequently because of the laboratory findings suspecting systemic vasculitis of which consisted CRP positivity, ESR elevation, perinuclear antineutrophil cytoplasmic antibodies (pANCA), and creatinine clearance reduction. The biopsy specimen revealed segmental necrotizing glomerulonephritis with frequent formation of a crescent. These findings confirmed the diagnosis of microscopic polyangitis. Oral administration of prednisolone with additional azathioprine following ethylprednisolone pulse therapy was effective, and pANCA was not detected anymore. We conclude that vasculitic neuropathy has to be considered as a possible cause of polyneuropathy.

Demyelinating Diseases↗

PubMed1997

Sigma ligands stimulate GTPase activity in mouse prefrontal membranes: evidence for the existence of metabotropic sigma receptor.

We studied effects of various sigma ligands on GTPase activity in mouse prefrontal membranes. Some representative sigma agonists, such as (+)-pentazocine, SA4503 and (+)-3-PPP, stimulated the GTPase activity in a concentration-dependent manner in ranges of 10 nM to 10 microM. Maximal effect was almost 10% increase to the control without treatment of drugs. However, another representative agonist, (+)-SKF10,047 showed only a partial activity with maximal effect 5% at 1 microM. NE-100, a representative antagonist, showed no effect at concentrations not more than 100 nM, while it did stimulate GTPase activity at 1 and 10 microM. Furthermore, these stimulative effects of both (+)-pentazocine and SA4503 on GTPase activity were significantly antagonized by NE-100 at 100 nM, suggesting that NE-100 possesses agonist-antagonist property. These findings suggest the possibility that there exist metabotropic sigma receptors.

Animals↗

PubMed1997

Early detection of graft function using hepatic venous oxygen saturation in pig liver transplantation.

In this study, we measured hepatic venous oxygen saturation (Shvo2) in pig liver transplantations in order to evaluate its usefulness as a predictor of early postoperative graft function. Shov2 of the grafts with good function was over 60% after reperfusion, and the mean Shov2 at end of the operations was 69.8+/-6.9%. Shov2 of the grafts with poor function never increased over 60%, and for most of the operation until its end, Shov2 was under 50%. At the end of the operations, the mean Shov2 was 39.7+/-5.5%. Shov2 levels of the grafts with good function were significantly higher than those of the grafts with poor function (P=0.0016). Corresponding with these Shov2 data, glutamic-oxaloacetic transaminase and lactate dehydrogenase levels of grafts with poor function were significantly higher than those of the grafts with good function. Shov2 represents a summation of the hemoglobin oxygen saturation at the venous end of the sinusoids of the liver and indicates adequate hepatic blood flow if the hepatic oxygen is constant. A decrease of Shov2 in poor graft function might indicate a disturbance of microcirculation in the sinusoids. Through the use of Shov2, we are able to recognize conditions of microcirculatory disturbance more quickly than with any other system. In conclusion, Shov2 is a useful indicator for an early and reliable prediction of outcome in liver transplantation.

Animals↗

PubMed1997

Vascular endothelial growth factor increases endothelin-converting enzyme expression in vascular endothelial cells.

Endothelin-converting enzyme-1 (ECE-1) is a key enzyme in endothelin processing. Although it has been revealed that ECE-1 expression increases in vascular wall after balloon injury in vivo experimental models, the regulation of ECE-1 expression in vitro remains undefined. In this study, we demonstrated that the endothelial cell-specific mitogen, vascular endothelial growth factor (VEGF) increased ECE-1 expression in cultured bovine aortic endothelial cells (BAEC). Northern blot analysis revealed that VEGF increased ECE-1 mRNA expression in 12-24 hours by 2-fold in BAEC, and this effect was dose-dependent. VEGF also increased ECE-1 protein expression detected by immunoblotting in 36 hours in BAEC. Therefore, VEGF increased ECE-1 expression in BAEC, which suggests that ECE-1 induction by VEGF may be involved in endothelin-system upregulation under pathological conditions such as neointimal formation and atherosclerosis.

Animals↗

PubMed1997

Genomic structure and chromosomal localization of GML (GPI-anchored molecule-like protein), a gene induced by p53.

Among its known functions, tumor suppressor gene p53 serves as a transcriptional regulator and mediates various signals through activation of downstream genes. We recently identified a novel gene, GML (glycosylphosphatidylinositol (GPI)-anchored molecule-like protein), whose expression is specifically induced by wildtype p53. To characterize the GML gene further, we determined 35.8 kb of DNA sequence that included a consensus binding sequence for p53 and the entire GML gene. The GML gene consists of four exons; and the p53-binding sequence is present in the 5'-flanking region. In genomic organization this gene resembles genes encoding murine Ly-6 glycoproteins, a human homologue of the Ly-6 family called RIG-E, and CD59; products of these genes, known as GPI-anchored proteins, are variously involved in signal transduction, cell-cell adhesion, and cell-matrix attachment. FISH analysis revealed that the GML gene is located on human chromosome 8q24.3. Genes encoding at least two other GPI-anchored molecules, E48 and RIG-E, are also located in this region.

Animals↗

PubMed1997

Detection of p53 gene mutations in fine-needle aspiration biopsied breast cancer specimens: correlations with nuclear p53 accumulations and tumor DNA aneuploidy patterns.

Using the polymerase chain reaction and a single strand conformation polymorphism (PCR-SSCP) analysis, p53 gene mutations have been examined preoperatively in aspirated biopsy specimens from 22 breast cancers. In eight (36%) of the studied cases, abnormal bands indicating mutations were detected and were more frequently present in common invasive breast carcinomas. Eight of the breast cancer cases were found to be positive for mutations: direct DNA sequencing confirmed eight mutations and revealed G to A and A to G nucleotide changes in five (63%) and two (25%) cases, respectively. The mutations that were localized at the CpG site of the gene were seen in three cases. Additionally, an immunohistochemical investigation of the presence of the p53 protein and a DNA flow-cytometrical analysis of the 22 resected breast cancers were also performed. Nuclear p53 protein accumulations and a DNA aneuploidy pattern were detected in 11 (50%) cases and in 16 (73%) cases, respectively, and both significantly correlated with p53 gene mutations (P < 0.01 and P < 0.001, respectively; Fisher's exact test). In contrast, in five cases of a breast cancer with a lower histologic grade, no p53 gene mutations, nuclear p53 protein accumulations, or DNA aneuploidy patterns were detected. These results thus suggest that p53 gene mutations, nuclear accumulations of the p53 protein, and a DNA aneuploidy pattern are events that occur with close relationship in the progression of a breast cancer, and that p53 abnormalities appear to correlate with a high grade of the malignancy. Therefore, the detection of p53 gene mutations in aspirated biopsy specimens of breast cancers may be helpful for an accurate and rapid cytological diagnosis, which reflects the prognosis.

Adult↗

PubMed1997

Results of 1001 pancreatic resections for invasive ductal adenocarcinoma of the pancreas.

OBJECTIVE: To evaluate the recent results of pancreatic resection in patients with invasive ductal adenocarcinoma of the pancreas. DESIGN: Retrospective study. SETTING: Seventy-seven medical facilities belonging to the Japan Society of Pancreatic Surgery. PATIENTS: One thousand one patients who underwent a resection of the pancreas between January, 1, 1991, and December 31, 1994. MAIN OUTCOME MEASURES: Morbidity and survival after surgery for pancreatic cancer according to the modified TNM classification of the International Union Against Cancer. RESULTS: After pancreatic resection, the cumulative postoperative survival rates at 1 and 3 years were 44.5% and 10.3%, respectively. Patients with early-stage cancers had a more prolonged survival time, ie, the cumulative 3-year survival rates for patients with stage I or stage II cancers were 50.4% and 45.5%, respectively; the survival rates for patients with stage III and stage IVa and IVb cancers were 17.6%, 5.7%, and 0%, respectively. The survival rate for patients with N1 or N2 metastasis did not differ appreciably, and both groups had significantly better survival rates than patients with N3 metastasis (P < .001). A significant difference in the postoperative survival time of N1 metastasis was observed between patients with no lymph node dissection (mean survival, 326.4 days) and patients who received a lymph node dissection (D1) (mean survival, 478.2 days) (P < or = .01). CONCLUSIONS: The recent results of pancreatic resection for invasive ductal adenocarcinoma of the pancreas are generally unsatisfactory. Although the outcome of the patients with an N1 metastasis can be improved if they receive N1 lymph node dissection (D1), an extensive lymph node dissection in advanced cancers does not necessarily produce a favorable prognosis.

Adult↗

PubMed1997

Bacterial lipopolysaccharide reduced intestinal barrier function and altered localization of 7H6 antigen in IEC-6 rat intestinal crypt cells.

The intestinal epithelial barrier restricts the passage of potentially toxic substances into the systemic circulation and is considered to be mostly mediated by tight junctions, though the mechanisms involved in the regulation of intestinal tight junctions are not yet fully understood. In the present study, we examined whether bacterial lipopolysaccharide (LPS) altered the barrier function of tight junction and localization of tight junctional proteins, ZO-1 and 7H6 antigen, in IEC-6 intestinal cells. Administration of LPS to the basolateral surface of IEC-6 cells disrupted the barrier function and caused the disappearance of 7H6 antigen from the cell border, whereas LPS administered to the apical surface altered neither the barrier function nor the localization of 7H6 antigen in IEC-6 cells. On the other hand, the localization of ZO-1 was not influenced by these treatments of LPS. These results suggest that the interaction of LPS with the basolateral surface of intestinal epithelial cells disrupts the barrier function and 7H6 antigen take part in the maintenance of the barrier function in IEC-6 cells.

Animals↗

PubMed1997

Disparity between serotonin- and acetylcholine-provoked coronary artery spasm.

BACKGROUND AND HYPOTHESIS: Intrinsic vasoactive substances, such as serotonin and acetylcholine, are known to provoke coronary artery spasm in patients with vasospastic angina. It remains unclear, however, whether these different agents, which activate different receptors, produce spasms at the same sites in these patients. The present study was designed to clarify the disparity of receptor agonist-induced coronary artery spasms in the same patients. METHODS: We conducted sequential provocative tests of coronary artery spasm by acetylcholine, serotonin, and ergonovine in 20 patients with rest angina examined with quantitative coronary angiography. RESULTS: Coronary artery spasms were provoked in all patients at 27 spastic sites. In 13 patients, ergonovine provoked spasms and in 10 of 13 patients who were diagnosed with variant angina, both acetylcholine and serotonin provoked spasms at the same sites where ergonovine also did. In 4 of 13 patients, spasms were provoked by serotonin but not by acetylcholine. In the remaining seven patients, whose spasms were induced by ergonovine, spasms were produced by acetylcholine but not by serotonin. On coronary angiography, the spastic sites for both acetylcholine and serotonin, and those for serotonin alone, were located in the proximal segments of coronary arteries, whereas the spastic sites for acetylcholine alone were located in the distal segments. CONCLUSIONS: This study documented the disparity between serotonin- and acetylcholine-induced spasms. Provocative tests using agents that activate different receptors may produce coronary artery spasms at the same and/or different sites, and this disparity may reflect the clinical heterogeneity of vasospastic ischemic syndrome.

Acetylcholine↗

PubMed1997

Characterization, guanosine 5'-O-(3-thiotriphosphate) modulation, daily variation, and localization of melatonin-binding sites in the catfish (Silurus asotus) brain.

Characteristics, guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS) modulation, daily variation, and localization of melatonin-binding sites in the brain of a nocturnal teleost, the catfish Silurus asotus, were studied by radioreceptor assay using 2-[125I]iodomelatonin as the radioligand. The specific binding was rapid, stable, saturable, and reversible. The radioligand binds to a single class of receptor site with an affinity (Kd) of 30.7 +/- 7.3 pM and total binding capacity (Bmax) of 9.76 +/- 0.79 fmol/mg protein (mean +/- SE, n = 5). The binding sites were highly specific for 2-iodomelatonin and melatonin. The specificity was almost identical to that of functional melatonin receptors in the dermal and epidermal melanophores in this species and that of ML-1 subtype melatonin receptors in vertebrates, including melatonin-binding sites in the goldfish brain. GTPgammaS treatment altered both the Kd and Bmax values, indicating that melatonin-binding sites in the catfish brain are coupled to G protein. The Bmax values exhibited no daily variation under light-dark cycles of 12 hr light:12 hr dark whereas plasma melatonin levels and Kd fluctuated in a rhythmic fashion. The density of melatonin-binding sites in discrete brain areas was determined to be highest in optic tectum-thalamus and hypothalamus, intermediate in telencephalon, cerebellum, and medulla oblongata, and lowest in olfactory bulbs. These results suggest that melatonin secreted from the pineal organ and/or retina plays neuromodulatory roles in the catfish brain via G protein-coupled melatonin receptors. Characteristics of melatonin receptors seem to be highly conserved during evolution, although the density of melatonin receptors is not regulated by melatonin itself in this species.

Animals↗

PubMed1997

Close correlation between increased sialyl-Lewisx expression and metastasis in human gastric carcinoma.

Expression of sialyl-Lewisx (sLex) antigen was studied immunohistochemically in 110 resected human gastric carcinomas using an anti-sLex monoclonal antibody. Lymph node, liver, and peritoneal metastases were clearly more prevalent in tumors expressing high levels of sLex than in those with no or low-level sLex expression. No correlation was found between sLex expression and histologic grade or histologic type of the Lauren classification. Among the tumors with lymph node metastasis, 44% expressed high levels of sLex in both the primary tumor and involved lymph nodes, and 14% of the metastatic lesions demonstrated increased sLex expression. The 5-year survival rate of the patients undergoing complete (R0) gastric resections was 60% in the sLex high-expression group, which was significantly lower than that of the sLex low-expression group (81%) and of the no-expression group (87%) (p < 0.05). These results suggest that high-level sLex expression is related to both an increased risk of metastasis and poor prognosis in gastric cancer patients.

Adult↗

PubMed1997

The effect of change in skin temperature due to evaporative cooling on sweating response during exercise.

The purpose of this study was to investigate whether there are any effects of skin temperature changes on sweating response in the first few minutes of mild exercise. Six healthy males performed a bicycle exercise at 100 W (50 rpm) for 30 min under an ambient temperature of 23 degrees C (40% RH). Esophageal temperature (Tes), mean skin temperature (Tsk), local skin temperature at the lower left scapula (Tsl), local sweating rate (Msw) and cutaneous blood flow by laser-Doppler flowmetry (LDF) were measured continuously. Although Tsl decreased markedly just after the onset of sweating, Tsk did not change. Msw did not increase constantly in the early stages of exercise, and there was a temporary interruption in the increase of Msw. This interruption in sweating was affected by the rate of change in Tsl rather than by the absolute value of Tsl, since there was a positive and significant correlation between the time of the interruption in the increase of Msw and the rate of decrease in Tsl (y = 6.47 x +0.04; r = 0.86, P < 0.05). The results suggest that sweating response in the early stages of exercise may be influenced by changes in local skin temperature due to evaporative cooling.

Adult↗