Search PubMed⌕ Search

Biomedical subjects

Hitoshi Yokoyama

Publications and source records attributed to Hitoshi Yokoyama.

At least 55 records · Page 3Linked to original sources
PubMed2004

A surgical case of aortic valve replacement in patient with chronic idiopathic thrombocytopenic purpura.

A 64-year-old man was presented to another hospital with bleeding from the upper jaw with a platelet count of 0.1 x 10(4)/microl one year ago, and idiopathic thrombocytopenic purpura complicated with aortic stenosis and regurgitation was diagnosed. Corticosteroid administration was initiated and the patient was admitted to our hospital for surgery two months after confirmation of symptoms associated with cerebral ischemia. Corticosteroid was administered for one year until the day of surgery, and aortic valve replacement was performed with a platelet count of 8.4 x 10(4)/microl. During surgery, bleeding tendency with decreased platelets was confirmed, which was corrected with intraoperative platelet transfusion, postoperative gamma-globulin administration, and postoperative oral corticosteroid administration. Caution must be exercised against perioperative bleeding tendency in open heart surgery, even when platelet count is maintained using small amounts of preoperative corticosteroid.

Aortic Valve Stenosis↗
PubMed2004

Repair of the aortico-left ventricular tunnel originating from the right aortic sinus with severe aortic valve regurgitation.

A 31-year-old adult with an aortico-left ventricular tunnel (ALVT) arising from the right aortic sinus is reported. Preoperative transesophageal echocardiography demonstrated a ruptured sinus of Valsalva with severe aortic valve regurgitation which originated from the right coronary sinus entering the outlet portion of the left ventricular outflow tract. Operation revealed the aortic entrance of the tunnel was above the right coronary sinus. Direct closure of the orifice of the tunnel using three stitches of 4-0 polypropylene with felt and aortic valve replacement (AVR) was performed. At 10-month follow-up the patient is asymptomatic and receiving no oral medications except anticoagulants. We believe this to be the oldest case of ALVT managed with AVR.

Adult↗
PubMed2004

[Temporary vena cava filters for prevention of pulmonary embolism].

Pulmonary embolism (PE) is a serious complication in deep venous thrombosis (DVT), and the prevention of PE is a major target of treatment. Vena cava filters (VCF) can be inserted, and the temporary type and retrievable type of VCF have appeared in recent years in addition to permanent models. These have introduced new criteria for VCF insertion and changes in the algorithm for the treatment of PE. Among cases traditionally calling for permanent VCF, those requiring prevention of PE, especially in the early stage, are suitable for temporary VCF insertion. These include floating thrombi in the acute DVT phase, the perioperative period of thrombectomy or endovascular treatment for DVT, surgery for an abdominal mass compressing the vena cava or iliac veins, and secondary prophylaxis in the early stage of PE. High-risk patients such as parturient cases with DVT and those with multiple traumatic injuries should also be considered. However, there is little evidence concerning temporary VCF, and further investigations are necessary on insertion methods and indications.

Humans↗
PubMed2004

[Membranous nephropathy].

Membranous nephropathy (MN) is a frequent cause of nephrotic syndrome in adults. A considerable diversity of prognosis is seen with idiopathic MN. We overview the recent progress of clinicopathological research, especially the initial factors affecting the longterm outcome of idiopathic MN. We studied retrospectively 105 patients with idiopathic MN and could assign the patients to two different groups based on the electron microscopic (EM) findings. In the homogeneous type only one patient developed end-stage renal failure, and earlier remission occurred in this group. With regard to secondary outcome, increased age, focal segmental glomerular sclerosis, arteriolosclerosis, heterogeneous type of EM findings were independent risk factors. Our results suggest that a new EM classification at initial biopsy is an independent indicator of prognosis in human idiopathic MN.

Adult↗
PubMed2003

Significant prolongation of animal survival by combined therapy of FR167653 and cyclosporine A in rat renal allografts.

BACKGROUND: Cyclosporine A (CsA) has improved short-term results in renal transplantation. However, its toxicities have been serious problems in clinical patients undergoing long-term administration. It is necessary to develop a nonnephrotoxic immunosuppressant that allows reducing doses of CsA. The authors tested the effect of a new pyrazolotriazin compound, FR167653 (FR), that inhibits the production of proinflammatory cytokines, using a rat renal acute-rejection model (Wistar-Lewis). METHODS: The authors first examined the adverse reactions of FR in naive rats. The effect of FR monotherapy was evaluated by treating allograft recipients at a dosage of 32 or 64 mg/kg/day intraperitoneally. The synergistic effect of FR and CsA at a minimum dose was examined by treating the recipients daily with 64 mg/kg of FR and 0.1, 0.5, or 1.0 mg/kg of CsA. RESULTS: Long-term administration of FR caused no severe adverse reactions in naive rats at less than 96 mg/kg/day, and FR is a nonnephrotoxic but liver-toxic agent at higher doses. Monotherapy of FR (8.7+/-1.3 days) or CsA (8.7+/-1.7 days) did not influence graft survival (vs. 8.2+/-0.8 in controls, n=10). However, the combined treatment of FR and CsA significantly prolonged animal survival (>50% of animals survived a 42-day follow-up period; P<0.01 vs. all other groups, n=15/group). Immunologic analysis demonstrated the significantly decreased production of major inflammatory mediators and adhesion molecules in the allografts as compared with those of all other groups. CONCLUSIONS: A nonnephrotoxic agent, FR may be a promising candidate for a new combined immunosuppressive regimen that potentially reduces the amount of CsA.

Animals↗
PubMed2003

Immunomodulation effects and clinical evidence of apheresis in renal diseases.

This article overviews the immunomodulation effects and clinical evidence of apheresis in renal diseases, in particular primary and secondary glomerulonephritis. A considerable permeability factor(s) derived from circulating T cells is speculated to have a crucial role in the proteinuria of nephrotic syndrome (NS). Plasma exchange (PE), immunoadsorption using Protein A sepharose cartridges, low-density lipoprotein apheresis and lymphocyte apheresis (LCAP) were tried to remove such factors or pathogenic T cells. Other glomerular diseases induced by specific antibodies such as antiglomerular basement membrane antibodies, antineutrophil cytoplasmic antibodies and immune-complexes such as lupus nephritis were also treated with PE, double filtration plasma apheresis. IAPP and LCAP. Many reports suggested that apheresis might have beneficial immunomodulation effects for the treatment of glomerular diseases: however, the recommendations based on evidence from small cohorts remain at low-level in most.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2003

p38 Mitogen-activated protein kinase contributes to autoimmune renal injury in MRL-Fas lpr mice.

The phosphorylation of p38 mitogen-activated protein kinase (MAPK) is responsible for the production and signal transduction of cytokines and chemokines. This study hypothesized that p38 MAPK activation is required for spontaneous autoimmune renal injury in MRL-Fas(lpr) mice, resembling human lupus erythematosus. FR167653, a specific inhibitor of p38 MAPK, is orally administrated from 3 or 4 mo of age in MRL-Fas(lpr) mice (at doses of 10 or 32mg/kg per day) until 6 mo of age. The phosphorylated p38 MAPK in kidneys of MRL-Fas(lpr) mice was evaluated. The number of phosphorylated p38 MAPK-positive cells was increased in diseased kidneys. The daily oral administration of FR167653 decreased p38 MAPK phosphorylation in kidneys, especially in a group of mice administered FR167653 (32 mg/kg per day) daily from 3 to 6 mo of age. FR167653 reduced the accumulation of macrophages and T cell and prevented kidney pathology, resulting in prolonged survival. In addition, FR167653 reduced expression of MCP-1 and TNF-alpha in the diseased kidneys and cultured tubular epithelial cells. Furthermore, FR167653 decreased IgG levels in the diseased kidneys and circulation. These results suggest that the phosphorylation of p38 MAPK is required for the pathogenesis of renal injury in MRL-Fas(lpr) mice followed by subsequent expression of renal cytokine/chemokine and IgG production. This study provides evidence that the regulation of p38 MAPK is a novel target for the therapy of renal injury in systemic lupus erythematosus.

Animals↗
PubMed2003

Gene therapy expressing amino-terminal truncated monocyte chemoattractant protein-1 prevents renal ischemia-reperfusion injury.

Ischemia-reperfusion is closely associated with tissue damage in various organs, including kidney. Despite clinical investigations, useful therapy for renal ischemia-reperfusion injury is not available so far. This study evaluated therapeutic effects of gene therapy expressing an amino-terminal deletion mutant of MCP-1 called 7ND to inhibit monocyte chemoattractant protein (MCP)-1/CCR2 signaling in vivo on renal ischemia-reperfusion injury. 7ND gene was transferred into the femoral muscle of Balb/c mice. Renal artery and vein of the left kidney were occluded with a vascular clamp for 60 min. A large number of infiltrated cells were observed, as was marked acute tubular necrosis in outer medulla after renal ischemia-reperfusion injury in control mice, while these lesions were significantly decreased in 7ND gene-transfected mice. Macrophages in the interstitial region, most of which were CCR2-positive, were markedly decreased in 7ND gene-transfected mice after reperfusion. Although macrophages infiltrated around MCP-1-positive cells in control mice, the smaller number of F4/80-positive cells could infiltrate into the neighbor of MCP-1-positive cells in 7ND-treated mice. These results provide evidence that gene therapy by 7ND is potentially a powerful therapeutic approach to inhibit MCP-1/CCR2 signaling, resulting in rescue from renal ischemia-reperfusion injury.

Animals↗
PubMed2003

CCR2 signaling contributes to ischemia-reperfusion injury in kidney.

Examined were CCR2-deficient mice to clarify the contribution of macrophages via monocyte chemoattractant protein 1 (MCP-1 or CCL2)/CCR2 signaling to the pathogenesis of renal ischemia-reperfusion injury. Also evaluated was the therapeutic effects via the inhibition of MCP-1/CCR2 signaling with propagermanium (3-oxygermylpropionic acid polymer) and RS-504393. Renal artery and vein of the left kidney were occluded with a vascular clamp for 60 min. A large number of infiltrated cells and marked acute tubular necrosis in outer medulla after renal ischemia-reperfusion injury was observed. Ischemia-reperfusion induced the expression of MCP-1 mRNA and protein in injured kidneys, followed by CCR2-positive macrophages in interstitium in wild-type mice. The expression of MCP-1 was decreased in CCR2-deficient mice compared with wild-type mice. The number of interstitial infiltrated macrophages was markedly smaller in the CCR2-deficient mice after ischemia-reperfusion. CCR2-deficient mice decreased the number of interstitial inducible nitric oxide synthase-positive cells after ischemia-reperfusion. The area of tubular necrosis in CCR2-deficient mice was significantly lower than that of wild-type mice after ischemia-reperfusion. In addition, CCR2-deficient mice diminished KC, macrophage inflammatory protein 2, epithelial cell-derived neutrophil-activating peptide 78, and neutrophil-activating peptide 2 expression compared with wild-type mice accompanied with the reduction of interstitial granulocyte infiltration. Similarly, propagermanium and RS-504393 reduced the number of interstitial infiltrated cells and tubular necrosis up to 96 h after ischemia-reperfusion injury. These results revealed that MCP-1 via CCR2 signaling plays a key role in the pathogenesis of renal ischemia-reperfusion injury through infiltration and activation of macrophages, and it offers a therapeutic target for ischemia-reperfusion.

Animals↗
PubMed2003

A report of a surgical case of papillary fibroelastoma in the left ventricular outflow tract.

While a 74-year-old man with a past history of cerebral infarction was undergoing surface echocardiography due to transient atrial fibrillation, an unstable, pedunculated tumor was detected in the left ventricular outflow tract. As the results of transesophageal echocardiography suggested a left ventricular tumor, semi-emergency surgery was performed. Based on pathological findings, the tumor was diagnosed as papillary fibroelastoma. This tumor mainly affects the cardiac valves and is often discovered during open-heart surgery or autopsy. This report presents a very rare case of preoperatively identified papillary fibroelastoma in the left ventricular outflow tract.

Aged↗
PubMed2003

CT features of chronic contained rupture of an abdominal aortic aneurysm.

Four cases among the 149 patients who required repair of an infrarenal abdominal aortic aneurysm (AAA) during the last five years, were chronic contained rupture. The first symptom at onset was back pain and physical examination revealed the patients to be in no acute distress. The sites of rupture were posterior in all cases. They were operated through an extraperitoneal approach. There was no operative mortality and all survived. The CT features, (1) discontinuity of the rim of calcification in the true aneurysm wall, (2) well defined soft tissue density adjacent to the aorta, (3) the concealed psoas muscle and the displaced viscera depending on the size of the lesion, and (4) no appearance of contrast material in the hematoma in some cases, led to the correct diagnosis of contained rupture.

Aged↗
PubMed2003

A surgical case of combined valvular disease complicated by absent right superior vena cava and persistent left superior vena cava.

A 74-year-old man with combined valvular disease with a recent cerebral infarction was admitted. While undergoing thorough examination for valvular disease, absent right superior vena cava (RSVC) and persistent left superior vena cava (PLSVC) were recognized. Chest X-ray film suggested a right arch protrusion, and CT and venogram confirmed the diagnosis. During surgery, replacement of the mitral and aortic valves and annuloplasty of the tricuspid valve were performed. A blood draining cannula was inserted in retrograde fashion from the coronary sinus into the PLSVC, without any difficulties in the tricuspid valve repair. Due to bradycardic atrial fibrillation, we believed that it would be difficult to insert an endocardial electrode postoperatively, hence myocardial electrode was placed in the right ventricular wall. Absent RSVC combined with PLSVC is very rare, and a patient who underwent combined valve surgery with this rare anatomical abnormality is herein presented.

Aged↗