Search PubMed⌕ Search

Biomedical subjects

H Kiyama

Publications and source records attributed to H Kiyama.

At least 73 records · Page 4Linked to original sources
PubMed1998

[A case report of mitral valve replacement using a parasternal incision (minimally invasive cardiac surgery) with pleuritis tuberculosa and after esophagus operation].

A 68-year-old man underwent mitral valve replacement because of mitral regurgitation (prolaps of anterior mitral leaflet) using parasternal incision (Delos M. Cosgrove, minimally invasive surgery). He had been treated as pulmonary tuberculosis previously and had undergone esophagus operation using stomach role reconstruction beneath the sternum four years before the mitral valve procedure. We could not select median-sternotomy as an approach due to stomach role beneath the sternum, nor left posterolateral thoracotomy because of the heavy left-side pleural adhesion. Cardio-pulmonary bypass cannulations were performed through the same incision, because severe atherosclerosis was found at the distal arteries of the abdominal aorta.

Aged↗
PubMed1998

[Autologous blood donation with recombinant human erythropoietin prior to elective cardiac surgery in anemic patients].

Despite the reducing exposure to allogeneic blood in cardiac surgery, most of patients with anemia still require allogeneic blood. In this study, we have attempted to harvest the blood from cardiac patients with baseline hemoglobin levels below 11.0 g/dl using recombinant human erythropoietin (rHuEPO). 29 anemic patients undergoing cardiac surgery at our hospital between January 1994 and March 1997 were divided into two groups: 3 weeks' treatment with recombinant human erythropoietin (rHuEPO) and blood donation (group 1, n = 15) and iron supplementation alone (group 2, n = 14). There were no statistically significant differences among the two groups in patients characteristic and surgical data. No serious adverse events after phlebotomy were apparent in patients donating autologous blood. Patients in group 1 had significantly higher hemoglobin levels than patients in group 2 at 7 days before operation. The number of reticulocytes were increased at just before operation in group 1, whereas group 2 showed no significant increase. The estimated hemoglobin increase in group 1 were higher at 7 days and just before operation. In 75% of group 1, allogeneic blood transfusion could be avoided, while all patients in group 2 received allogeneic blood transfusion. This study suggests that the combination of rHuEPO administration and autologous blood donation would be beneficial for anemic patients in elective cardiac surgery. The use of rHuEPO should not be restricted to anemic patients.

Aged↗
PubMed1998

[Re-do surgery with minimally invasive cardiac surgery (MICS): mitral valve replacement 6 years after open mitral commissurotomy].

A 60-year-old man, who had undergone open mitral commissurotomy 6 years ago, underwent re-do surgery (mitral valve replacement) with minimally invasive cardiac surgery (MICS), using lower partial sternotomy to the height of the right side second intercostal space. Cannulation of the heart was carried out placing a cannula directly into the superior vena cava and a second cannula in the inferior vena cava via the right atrium. Arterial return was through the ascending aorta. Cardioplegia was administered directly into the ascending aorta with intermittent perfusion. Valve replacement was performed by opening directly right side left atrium.

Cardiac Surgical Procedures↗
PubMed1998

[Thoracoabdominal aortic repair without using assisted bypass].

A 41-year-old man, who had undergone descending aortic repair following rupture of the DeBakey type III aortic dissection, underwent thoracoabdominal aneurysm repair 1 year after the first surgery. The operation was performed by partial-clamping and single crossclamping without using assisted bypass or shunt, in order to minimize bleeding ensuing the re-thoracotomy and dissection between lung and the graft.

Adult↗
PubMed1997

Cytokine-induced neutrophil chemoattractant gene expression in the rat hypothalamus by osmotic stimulation.

Cytokine-induced neutrophil chemoattractant (CINC) is one of the chemokines and has chemotaxity for neutrophils. Recently, we found the presence of stress-sensitive CINC expression in the hypothalamic nuclei such as the paraventricular nucleus. Since CINC was predominantly co-localized with vasopressin in the supraoptic nucleus (SON), we investigated the effect of hyperosmotic challenge on CINC mRNA in the hypothalamus. We found that CINC mRNA expression in the hypothalamus was augmented within 30 min following osmotic stimulation and immediately returned to the basal level. The suckling, which is a stimulation to oxytocin neurons in the SON, has no effect on CINC mRNA expression in the hypothalamus. This is the first evidence that the chemokine in the brain is activated by osmotic stimulation.

Animals↗
PubMed1997

Changes in nitric oxide synthase-like immunoreactivities in unipolar brush cells in the rat cerebellar flocculus after unilateral labyrinthectomy.

To elucidate the role of nitric oxide (NO)-mediated signaling in vestibular compensation, we examined effects of unilateral labyrinthectomy (UL) on the neuronal isoform of NO synthase (NOS) expression in the rat central vestibular system using immunohistochemical techniques. After UL, a substantial number of NOS-like immunoreactive (-LIR) neurons were observed in the granule cell layer in bilateral flocculi, and these neurons were determined to be unipolar brush cells (UB cells) by their unique morphology and location. NOS-LIR UB cells appeared by 12 h with a maximum increase in number 24 h after UL, and then gradually disappeared in accordance with the development of vestibular compensation. Continuous floccular infusion of N(omega)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NOS, or 2-phenyl-4,4,5,5-tetramethyl-1-oxyl-3-oxide (PTIO), an inhibitor of NO, caused more severe vestibulo-ocular deficits at the initial stage after UL and slightly delayed the recovery from these symptoms. All these findings suggest that up-regulation of NO production in floccular UB cells facilitates vestibular compensation, especially at the initial stage after UL.

Animals↗
PubMed1997

Expression of vasoactive intestinal polypeptide receptor mRNA and secretory regulation by vasoactive intestinal polypeptide in rat submandibular and sublingual salivary glands.

Vasoactive intestinal polypeptide (VIP)-receptor mRNA was strongly expressed in the acinar cells in the submandibular gland but not in the sublingual gland. VIP-containing nerve fibres were richly distributed around acini in the submandibular gland but were rare around acini of the sublingual gland. In the submandibular gland, the chorda was stimulated at various frequencies (1-40 Hz) together with an infusion of (N-Ac-Tyr1, D-Phe2)-GRF(1-29)-NH2 (109 M), VIP antagonist, which reduced salivary flow from the submandibular gland only at high-frequency stimulation (> 20 Hz), and more markedly reduced the salivary protein concentration. When the chorda was continuously stimulated the antagonist reduced the salivary flow only during the initial 5 min. Exogenous VIP 10(-12) - 10(-8) M) infusion at the same time as chorda stimulation caused no increase in salivary flow, but the salivary protein concentration was increased in a dose-dependent manner. In the sublingual gland, neither VIP nor the VIP antagonist affected chorda-evoked salivary flow and protein concentration. Thus, endogenous VIP may play a part in the regulation of both fluid and protein secretion, especially of protein, evoked by chorda stimulation at high frequency in the submandibular gland. These phenomena occurred only in the initial phase of secretion. In the sublingual gland, it seems likely that VIP plays no part in the regulatory mechanism, at least with regard to salivary fluid secretion in the acinar cells.

Animals↗
PubMed1997

Noxious stimulation enhances release of cytokine-induced neutrophil chemoattractant from hypothalamic neurosecretory cells.

Cytokine-induced neutrophil chemoattractant (CINC), a member of IL-8 family in rat and a counter part of human growth-related oncogene product (GRO), was demonstrated to be synthesized in hypothalamic neurons and released in peripheral blood in response to noxious stimulation. CINC immunoreactive neurons were found mainly in supraoptic nucleus, while positive fibers were found in the median eminence and the posterior lobe of pituitary gland. Colchicine injection into the third ventricle demonstrated additional CINC positive neurons in both parvo- and magno-cellular parts of paraventricular nucleus, and an increase of positive fibers in the external layer of the median eminence. After formalin injection into the foot pad, CINC immunoreactivity substantially increased in the posterior lobe of the pituitary gland and in the external layers of the median eminence. In addition, a parallel increase of CINC level was noticed in the peripheral blood. It is suggested from the present results that, in response to a noxious stimulation, CINC is released from hypothalamic neurosecretory cells via both the anterior and posterior pituitary system. This cytokine mediated noxious response from CNS to peripheral tissue, would be a novel type of cross-talk between nervous and immune system.

Animals↗
PubMed1997

Expression of Glycine max (soybean agglutinin) binding molecule in injured motoneurons and its specific localization in the extracellular matrix between injured neurons and microglia.

In order to identify expression of molecules that are secreted or translocated into extracellular regions after nerve injury, lectin histochemistry using 16 lectins was carried out. After unilateral hypoglossal nerve transection, only Glycin max (soybean agglutinin; SBA) staining was apparent in the injured hypoglossal nucleus. The SBA staining was observed clearly from 3 days after the operation, and the most intense staining was observed around postoperative day 5-7. Thereafter SBA staining gradually decreased to an undetectable level by 21 days postoperative. Electron microscopic evaluation of the staining revealed it to be mainly concentrated in the extracellular region between injured motoneurons and microglia. In addition SBA staining was also found in the Golgi apparatus of injured motoneurons. These data suggest that injured motoneurons synthesize molecules to which SBA could bind in response to nerve injury, and that this molecule is secreted into the gap between microglia and injured neurons. This molecule may function as an adhesion or signalling molecule between injured neurons and microglia.

Animals↗
PubMed1997

Localization of molecules involved in cytokine receptor signaling in the rat trigeminal ganglion.

The localization of some cytokine receptors and their downstream intracellular signaling molecules was examined in the trigeminal ganglia of rats. Among cytokine receptor components, we examined signal transduction subchain, gp130, IL-2Rgamma and IL-5Rbeta, which are common to respective groups of cytokine receptors. Most of the sensory ganglion neurons expressed gp130, but not IL-2Rgamma nor IL-5Rbeta. We further examined the localization of Janus kinase (JAK) family members which were reported to be associated with various kind of cytokine receptors and are thought to be implicated in major cytokine receptor-signaling pathways [6,9,11,13]. While JAK1 and Tyk2 were expressed in all the type of neurons, JAK2 was predominantly expressed in the small neurons. In addition, JAK3 immunoreactivity was only found in satellite cells. The present results indicate that most of neurons express gp130, and that the localization of JAK family members differs with the cell type. This also suggests that the cytokine receptor-signaling pathway may be different in neuronal and glial cells.

Animals↗
PubMed1997

Role of the flocculus in the development of vestibular compensation: immunohistochemical studies with retrograde tracing and flocculectomy using Fos expression as a marker in the rat brainstem.

After unilateral labyrinthectomy in rats, Fos-like immunoreactive neurons appeared in the ipsilateral medial vestibular nucleus, contralateral prepositus hypoglossal nucleus and contralateral inferior olive beta subnucleus. and thereafter gradually disappeared in accordance with the development of vestibular compensation. This finding indicated that the activation of these nuclei is the initial event of vestibular compensation. In the present study, retrograde tracing experiments revealed that these Fos-like immunoreactive neurons project a proportion of their axons to the vestibulocerebellum (uvula-nodulus, flocculus). Before vestibular compensation was accomplished, right, left or bilateral flocculectomy was performed in right-labyrinthectomized rats. All these treatments caused reappearance of unilateral labyrinthectomy-induced behavioral deficits and Fos expression in the left medial vestibular nucleus and right prepositus hypoglossal nucleus. Since floccular efferents are GABAergic, these results indicate that the neurons in which Fos expression was detected by flocculectomy had been inhibited after unilateral labyrinthectomy by floccular Purkinje neurons and that disinhibition of these neurons induced by flocculectomy caused decompensation. Based on our present findings, we propose a hypothesis that the bilateral flocculus serves the restoration of balance between intervestibular nuclear activities to induce vestibular compensation after unilateral labyrinthectomy.

Animals↗
PubMed1997

Selective upregulation of cytokine receptor subchain and their intracellular signalling molecules after peripheral nerve injury.

Numerous studies have suggested that growth factors and cytokines play an important role in the survival of injured neurons and in neurite elongation. Therefore, intracellular signalling pathways activated by growth factors and cytokine receptors play an important role in neuronal survival or for the re-establishment of connection. Since the JAK (janus kinase)-STAT (signal transducers and activators of transcription) signal transduction pathway is known to play a major role in cytokine receptor signalling, we first examined regulation of JAK gene expression following peripheral nerve injury by in situ hybridization histochemistry. The rat hypoglossal nerve was axotomized unilaterally and the mRNA levels for JAK1, JAK2. JAK3 and TYK2 were examined in the hypoglossal nucleus at postoperative times ranging from 1 to 35 days. Among the JAK family members, JAK2 and JAK3 were substantially increased in injured hypoglossal motoneurons, whereas no significant increases were observed for JAK1 and TYK2. These changes were further confirmed by immunohistochemistry using antibodies specific to JAK2 and JAK3. In addition, we examined the JAK2 and JAK3 associated cytokine receptor components, IL-2R gamma and gp130, which are common to various cytokine receptors. Among these, gp130 immunostaining was upregulated after nerve injury. This was also confirmed by in situ hybridization. These results suggest that the injured neuron prepares the molecular machinery involved in certain cytokine receptor signalling pathways at an early phase of the regenerative process, accelerating for the neuron to respond to cytokines that may regulate survival and/or neurite elongation.

Animals↗
PubMed1997

Differential display reveals transcriptional up-regulation of the motor molecules for both anterograde and retrograde axonal transport during nerve regeneration.

RNA fingerprinting using an arbitrary primed polymerase chain reaction was carried out to compare differences in expression of mRNAs between axotomized and normal hypoglossal motoneurons in the mouse. In this survey, the kinesin light chain (KLC) was identified as a nerve injury-associated molecule. This was also confirmed by in situ hybridization using hemihypoglossal nerve-transected brain sections. In order to identify the exact species of molecules belonging to the KLC family, in situ hybridization was carried out with oligonucleotide probes specific to rat KLC A, KLC B and KLC C, using the rat hypoglossal nerve injury model. In addition, expression of both ubiquitous and neuron-specific kinesin heavy chain and cytoplasmic dynein which is a retrograde motor, was also examined. Expression of all the members of the KLC (A-C) family and dynein was up-regulated during nerve regeneration, whereas the abundant expression of the neuron-specific KHC mRNA was not changed. The present results indicate that the molecules associated with both anterograde and retrograde axonal transport are up-regulated in their expression during efferent motor nerve regeneration, suggesting that the retrograde transport of growth factors and anterograde transport of vesicles, providing membrane material, could be increased during motor nerve regeneration.

Amino Acid Sequence↗
PubMed1997

[Combined erythropoietin and aprotinin use for blood conservation in elderly coronary bypass patients].

Age is one of the predictors of homologous blood transfusion (HBT) in cardiac surgery. To avoid HBT, we have employed pharmacological blood conservation techniques such as the administration of erythropoietin (EPO) in conjunction with autologous blood donation (ABD) and the administration of aprotinin in prime volume. The effectiveness of these methods was evaluted in elderly patients who underwent coronary artery bypass grafting (CABG). Seventy-nine elective coronary bypass patients were classified into two groups by age: group A (> or = 70 y.o., n = 29) and group B (< 70 y.o., n = 46). EPO (24,000 U) was administered once a week subcutaneously starting 3 weeks before the operation. ABDs were carried out as long as the blood hemoglobin levels were above 10.5 g/dl. A significant increase of preoperative blood hemoglobin was observed in both groups. Although the blood hemoglobin levels at the beginning of ABD were lower in group A than in group B, the mean amount of predonated blood per patients was similar in both groups. In 79.3% of group A and in 84.8% of group B, HBT was not required: furthermore, in the prodonated patients, this no-HBT rate could be increased to 84.0% of group A and to 88.1% of group B. These results suggest that CABG in elderly patients can be performed safely without HBT when pharmacological blood conservation techniques are employed.

Age Factors↗
PubMed1997

[Significance of arterial ketone body ratio as a parameter of oxygen metabolism in cardiac surgery].

Postoperative course after cardiac surgery is characterized by a progressive increased cellular oxygen demand and limited oxygen supply. It is mandatory to assess the adequacy of tissue oxygenation and to correct inadequate oxygenation rapidly in cardiac surgery. The present study was designed to evaluate the relationship between the arterial ketone body ratio (AKBR) and the status of oxygen demand and supply relationship in cardiac surgery. We measured oxygen consumption, oxygen delivery, oxygen extraction, mixed venous oxygen saturation, lactate, lactate/pyruvate (L/P) and AKBR in 43 patients undergoing open heart surgery at selected 10 periods before, during and after cardiopulmonary bypass (CPB). AKBR significantly decreased immediately after the beginning of CPB and returned to pre-CPB level more quickly than lactate and L/P did. AKBR at several periods a significant correlation with lactate and L/P at delayed periods. There was a significant correlation between AKBR and L/P during and after CPB. Furthermore, oxygen consumption, oxygen extraction, mixed venous oxygen saturation, and lactate were correlated with AKBR significantly. But there was no correlation between the parameter of oxygen metabolism and both lactate and L/P. In conclusion, it appears from these data that AKBR in cardiac surgery may be helpful as a rapid guide for estimating the degree of anaerobiosis.

Arteries↗
PubMed1997

[The comparison of tepid and moderate hypothermic cardiopulmonary bypass in cardiac surgery].

Normothermic cardiopulmonary bypass (CPB) is being increasingly used at some institutions. Patients undergoing normothermic CPB have a higher systemic oxygen demand and may be at higher risk for ischemic injury. This study was designed to confirm the clinical efficacy and safety of tepid hypothermic CPB. Thirty-six patients undergoing open heart surgery between June 1993 and August 1994 were divided into two groups: tepid (n = 18, 32 degrees C) and moderate (n = 18, 26 degrees C) hypothermic CPB. There were no significant differences in preoperative and perioperative patients characteristics between the two groups. The mean aortic cross-clamp time did not differ between two groups, but the mean CPB time was significantly shorter in tepid hypothermic patients. Serum lactate after CPB and lactate/pyrvate ratio during CPB in tepid hypothermic patients were significantly lower than in moderate hypothermic patients. The mixed venous oxygen saturation in tepid hypothermic patients was significantly lower however, it was maintained at levels more than 70% during CPB. This study suggests that tepid hypothermic CPB is a safe and effective alternative to moderate hypothermic CPB for patients undergoing open heart surgery. Previous reports have documented that patients undergoing normothermic CPB are at greater risk for cerebral desaturation. We should evaluate cerebral venous oxygen saturation during tepid hypothermic CPB before the induction of normothermic CPB.

Cardiac Surgical Procedures↗
PubMed1996

p53-independent cyclin G expression in a group of mature neurons and its enhanced expression during nerve regeneration.

An increase in cyclin G expression after nerve injury was demonstrated by differential display PCR, carried out to compare references in expression of mRNAs between axotomized and normal hypoglossal motoneurons in the rat. The nerve injury dramatically upregulated the expression of cyclin G mRNA in the motoneurons during the early phase of the nerve regeneration process, suggesting an involvement of cyclin G in the early stage of nerve regeneration. In brain, in situ hybridization studies also demonstrated cyclin G expression in a restricted group of matured neurons, particularly in the telencephalon and the thalamus. This constitutive expression in mature neurons suggests that cyclin G may have a function different from other members of the cyclin group. In addition, although cyclin G has been shown to be a transcription target of p53, the upregulation of cyclin G in injured motoneurons, as well as the expression in the adult rat brain, was not affected in the p53-deficient mouse. These data suggest that the expression of cyclin G, at least in the nervous system, is not regulated by p53 predominantly, and that there may be alternative regulatory factors or pathways for cyclin G expression.

Animals↗