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Biomedical subjects

K Yokoi

Publications and source records attributed to K Yokoi.

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

Impairment of ocular surface epithelium barrier function in patients with atopic dermatitis.

AIMS: To assess the integrity of the ocular surface epithelium in patients with atopic dermatitis from the viewpoint of its barrier function. METHODS: 49 patients with atopic dermatitis with blepharoconjunctivitis (ABC group), 27 age matched patients with seasonal or perennial allergic conjunctivitis (AC group), and 20 volunteers with normal healthy eyes (NH group) were assigned to this study. Ocular surface epithelium barrier function was evaluated by the fluorophotometric method using a slit lamp fluorophotometer. 3 microliters of 0.5% sodium fluorescein was instilled into the conjunctival sac of the right eye and fluorescein uptake (ng/ml) 30 minutes later (20 minutes after eye washing) was measured in the central cornea and the temporal bulbar conjunctiva. Fluorophoto metric measurements performed were analysed in each group and compared between the groups. RESULTS: The ABC group showed significantly higher fluorescein uptake (mean 28.2 (SEM 3.3) ng/ml) in the cornea than the AC (11.4 (2.2), p = 0.001) and NH groups (9.3 (2.1), p = 0.001). There was no significant difference between the AC and NH groups (p = 0.930). The ABC group also showed significantly higher fluorescein uptake in the bulbar conjunctiva (393.4 (54.0)) than the AC (182.9 (24.6), p = 0.011) and NH groups (169.3 (29.1), p = 0.012). There was also no significant difference in fluorescein uptake between the AC group and the NH group (p = 0.987). CONCLUSION: This study suggested that ocular surface epithelium barrier function is impaired in patients with atopic dermatitis with blepharoconjunctivitis.

Adolescent↗
PubMed1998

[Intralobar pulmonary sequestration with three aberrant arteries: a case report and review of the Japanese literature].

A case of intralobar pulmonary sequestration with three aberrant arteries was reported. The patient was a 26-year-old man. His chest film showed an abnormal shadow suspected of a pulmonary sequestration in the left lower lobe of the lung. Computed tomography of the chest revealed that the aberrant arteries originated from the descending aorta and circulated the emphysematous area of the left lung. Angiography clearly demonstrated three aberrant arteries and three veins draining into the hemiazygos and lower pulmonary veins. Pulmonary sequestration was diagnosed and then resected. Microscopically, the resected lung had emphysematous change, multiple cysts and winded vessels. Aberrant arteries were the elastic type of vessels and accompanied with atherosclerosis. According to the review of 139 Japanese cases of intralobar pulmonary sequestration, 7% of all patients had more than two aberrant arteries. Moreover, only 3% of patients had veins draining into the systemic vessels. In many cases the thin aberrant arteries were clearly demonstrated by angiography and the draining veins were detected. We consider that angiography is necessary to show definitely the aberrant arteries and drainage veins.

Adult↗
PubMed1998

[Antiphospholipid antibodies in the elderly patients with ischemic stroke].

The importance of antiphospholipid antibodies as a cause of ischemic stroke in young adults is well demonstrated in the previous studies, but the relationship between the elderly patients with ischemic stroke and antiphospholipid antibodies is not defined. The frequency of positivity for antiphospholipid antibodies was 5.4% (6 out of 112 elderly patients with ischemic stroke), and much higher than that of the elderly healthy individuals (none of 108 individuals) (p < 0.001). Equal numbers of stroke patients with or without antiphospholipid antibodies had other stroke risk factors. The clinical features of the elderly patients with ischemic stroke, who were positive for antiphospholipid antibodies, presented recurrent and multiple infarct dementia, and had thromboses of the other organs. The hemostatic state of the patients with positive antiphospholipid antibodies revealed, in particular, increased intravascular coagulation. Antithrombotic treatment with warfarin at high international normalized ratios (INRs: 1.47-2.80) were effective comparing with antiplatelet treatment with ticlopidine alone in preventing further thromboembolic events.

Aged↗
PubMed1997

Cardiac dysfunction in patients with chronic progressive external ophthalmoplegia.

BACKGROUND: Chronic progressive external ophthalmoplegia (CPEO), which includes Kearns-Sayre syndrome, is a mitochondrial disorder with large deletions of mitochondrial DNA. Recently, mtDNA deletions in cardiac muscle cells were thought to be a cause of dilated cardiomyopathy. However, the cardiac involvement in patients with CPEO is generally considered to be limited to the cardiac conduction system. HYPOTHESIS: The purpose of this study was to evaluate left ventricular function in patients with CPEO. METHODS: We evaluated the cardiac function of five patients with CPEO by means of carotid pulse recording and Doppler echocardiography. RESULTS: The ratio of the pre-ejection period to ejection time was increased to 0.67 in one patient and to 0.50 in another. Echocardiography showed left ventricular dilatation and diffuse hypokinetic wall motion in both cases. Left ventricular fractional shortening was decreased to 5 and 19%, respectively, and the mean rate of circumferential shortening was decreased to 0.12 and 0.63 circ/s, respectively. One of the two patient died of congestive heart failure 2 months after the study. The Doppler pattern of left ventricular filling in the three remaining patients showed a decrease in the ratio of peak flow velocity in early diastole to that in late diastole, with an increase in deceleration time. CONCLUSION: Although cardiac involvement in patients with CPEO is generally considered to be limited to the cardiac conduction system, left ventricular dysfunction may be present and should receive more attention in the management of patients with CPEO.

Adult↗
PubMed1997

Attenuation of monosodium urate crystal-induced arthritis in rabbits by a neutralizing antibody against interleukin-8.

Accumulating evidence implicates interleukin-8 (IL-8) as an essential mediator in neutrophil-mediated acute inflammation. Neutrophils have also been shown to have a crucial role in the pathogenesis of acute gouty arthritis. Thus, we investigate the pathophysiological role of IL-8 in an experimental model of acute gout, monosodium urate (MSU) crystal-induced arthritis in rabbits. The injection of MSU crystals into knee joints caused a marked swelling of joints. Concomitantly, the infiltration ofleukocytes, mostly neutrophils, was observed in synovial membrane and synovial fluids. The injection of MSU crystals also induced an elevation in synovial fluid IL-8 levels preceding neutrophil infiltration into synovial fluids, without an accompanying increase in plasma IL-8 levels. Immunoreactive IL-8 protein was detected in synovial lining cells at 12-24 h after the injection. IL-8 protein was also observed in infiltrated leukocytes in synovium as early as 3-24 h after the injection. Finally, the intraarticular injection of a neutralizing anti-IL-8 antibody significantly attenuated the crystal-induced joint swelling that occurred at 12 h, and neutrophil infiltration into arthritic joints at 12 and 24 h after the induction. These results provide evidence on the pathogenic roles of locally produced IL-8 in MSU crystal-induced gouty arthritis.

Animals↗
PubMed1997

Pivotal role of interleukin-8 in the acute respiratory distress syndrome and cerebral reperfusion injury.

Neutrophil recruitment is one of the hallmarks of acute inflammation. A potent neutrophil chemotactic and activating factor, interleukin-8 (IL-8), has been demonstrated to be elevated in body fluids in various human diseases and experimental animal models. Recent investigations on animal disease models using blocking antibodies to IL-8 have revealed the essential involvement of IL-8 in acute inflammation. We previously reported that the administration of a neutralizing antibody against IL-8 prevented the neutrophil infiltration and neutrophil-mediated tissue injury in several animal studies. In addition, we have recently demonstrated that anti-IL-8 treatment is also effective in prevention of two models that are very relevant to clinical situations: cerebral reperfusion injury and endotoxemia-induced acute respiratory distress syndrome-like lung injury. These results further support the hypothesis that IL-8 has a pivotal role and is a novel target for therapeutic intervention in neutrophil-mediated injury.

Animals↗
PubMed1997

Effect of ischemia and partial outflow obstruction on rat bladder function.

We investigated the effects of ischemia induced by ligation of the bilateral internal iliac arteries following partial outlet obstruction on changes in detrusor function in rat. Rats were divided into three groups: sham-operated control rats, rats with partial outlet obstruction, and rats with obstruction+ischemia. Bladder function was studied by the in vitro organ bath technique 7 days after surgery. The weight of the bladder was significantly increased in both the obstruction and obstruction+ischemia groups. The obstruction+ischemia group exhibited a greater increase in weight. The passive length-tension relationship of detrusor muscle strips showed that tissue elasticity was decreased and the active length-tension relationship demonstrated that the peak response was observed at a shorter tissue length in the obstruction+ischemia group compared with the other two groups. There was no difference in the passive and active length-tension relationships between the control group and the obstruction group. The contractile response to various kinds of stimulation (field stimulation, bethanechol, ATP, and KCl) increased in the obstruction group and decreased in the obstruction+ischemia group. These findings suggest that partial outflow obstruction alone increased bladder contractility in response to stimuli. However, ischemia reduced the contractility and elasticity of the bladder wall.

Animals↗
PubMed1997

Epithelioid hemangioendothelioma presenting as a chest wall tumor.

We report a case of epithelioid hemangioendothelioma presenting as a chest wall tumor. The patient had invasive bladder carcinoma and a soft-density mass protruding into the left thoracic cavity from the lateral chest wall on a computed tomographic scan. Percutaneous needle biopsy was performed to obtain a definite diagnosis of the chest wall tumor. Because of an intrathoracic hemorrhage after the procedure, the patient underwent an emergency thoracotomy and excision of the mass with adjacent structures. Pathologic examination demonstrated the mass to be a subpleural epithelioid hemangioendothelioma. This rare tumor has never been reported previously as arising from the chest wall.

Aged↗
PubMed1997

Effects of alpha-interferon on sperm production, concentration, and motility in the rat.

BACKGROUND: We evaluated possible effects of alpha-interferon (alpha-IFN) on testicular spermatogenesis and epididymal sperm quality in the nude rat. METHODS: Nude male rats were administered subcutaneous injections of human alpha-IFN daily for 3 months. The luminal content of the cauda epididymidis was collected by micropuncture. Daily sperm production was determined by Amann's method and sperm concentrations were determined by microassay. Progressive motility was judged by evaluating the linear distance traveled by the sperm in a diluent. Serum levels of testosterone, luteinizing hormone (LH), and follicle stimulating hormone (FSH) were also measured at the end of the experiment. RESULTS: Daily sperm production and epididymal sperm concentrations were significantly increased after administration of alpha-IFN, while progressive motility of the spermatozoa was not altered. Alpha-IFN significantly increased serum testosterone levels, while it decreased serum LH levels and left serum FSH levels unchanged. CONCLUSION: Alpha-IFN may improve testicular spermatogenesis and increase the epididymal sperm concentration in the rat. These promising results with alpha-IFN may pave the way for a new approach to treating male infertility.

Animals↗
PubMed1997

Effects of flavonoids isolated from scutellariae radix on the production of tissue-type plasminogen activator and plasminogen activator inhibitor-1 induced by thrombin and thrombin receptor agonist peptide in cultured human umbilical vein endothelial cells.

The effects of different flavonoids isolated from the roots of Scutellaria baicalensis Georgi on the production of tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) induced by thrombin and thrombin receptor agonist peptide, Ser-Phe-Leu-Leu-Arg-Asn-Pro-Asn-Asp-Lys-Tyr-Glu-Pro-Phe, have been examined in cultured human umbilical vein endothelial cells (HUVECs). Thrombin and thrombin receptor agonist peptide induced production of both t-PA and PAI-1 and the elevation of intracellular free calcium concentration ([Ca2+]i). Baicalein isolated from Scutellariae Radix dose-dependently inhibited PAI-1 production induced by thrombin and thrombin receptor agonist peptide; its concentrations for 50% inhibition (IC50) were 6.8 and 3.5 microM, respectively. Other flavonoids had no effect. In contrast, flavonoids isolated from Scutellariae Radix had no effect on production of t-PA induced by thrombin and thrombin receptor agonist peptide. Baicalein inhibited the elevation of [Ca2+]i induced by thrombin and thrombin receptor agonist peptide and, at a concentration of 1000 microM, slightly increased t-PA production. These findings suggest that the mechanism by which baicalein inhibits PAI-1 production induced by thrombin and thrombin receptor agonist peptide might be by reduction of [Ca2+]i elevation. The results suggest that baicalein in Scutellariae Radix might be active as a drug in the treatment of arteriosclerosis and thrombosis.

Calcium↗
PubMed1997

Effects of partial outflow obstruction on bladder contractility and blood flow to the detrusor: comparison between mild and severe obstruction.

Detrusor dysfunction secondary to partial outflow obstruction is caused in part by decreased blood flow to the detrusor. We investigated changes in blood flow to the bladder and in bladder function after inducing partial outflow obstruction. The urethras of male Sprague-Dawley rats were constricted by sutures to degrees representing either mild and severe obstruction. Blood flow to the bladder was measured by a Doppler flowmeter prior to and 7 days after obstruction. In vivo and in vitro experiments were performed 7 days after surgery. After cystometry was used to determine bladder capacity, the pressure at which micturition was induced, and maximum voiding pressure, the bladder was removed and placed in an organ bath where increases in intravesical pressure in response to field stimulation were evaluated. Finally, volume-pressure studies were performed in order to determine passive detrusor compliance and response to field stimulation at each specific capacity in vitro. Although blood flow to the bladder was significantly decreased by severe obstruction, no differences in blood flow between control and mildly obstructed bladders was observed. While maximum voiding pressure decreased in severely obstructed bladders, both the pressure at which micturition was induced and bladder capacity were increased. The response to field stimulation was increased by mild obstruction but decreased by severe obstruction, although bladder compliance was increased by both. The peak response to filled stimulation was observed at a larger capacity in severely obstructed bladders than the others. In conclusion, when outflow obstruction was mild, blood flow to the bladder remained unchanged and detrusor contractility increased. On the other hand, severe obstruction decreased bladder blood flow and induced deterioration of detrusor function.

Animals↗
PubMed1997

Prevention of endotoxemia-induced acute respiratory distress syndrome-like lung injury in rabbits by a monoclonal antibody to IL-8.

We have herein established an endotoxemia-induced acute respiratory distress syndrome (ARDS)-like lung injury administered a sublethal dose of lipopolysaccharide (LPS) intravenously 36 hours after the intratracheal instillation of heat-killed Streptococcus pyogenes (OK-432). At 36 hours after OK-432 priming, a mild infiltration into the lungs, consisting of a small number of neutrophils and macrophages, was observed without destruction of pulmonary architecture. A subsequent challenge with a sublethal dose of LPS induced pathologic changes characteristic of ARDS--such as extensive edema in alveolar lumina, marked infiltration composed of a large number of neutrophils and a few macrophages, fibrin deposit in alveolar space, and destruction of pulmonary architecture--resulting in severe hypoxemia. Concomitantly, LPS challenge after priming with OK-432 induced a marked elevation of IL-8 levels in serum and bronchoalveolar lavage fluid with local IL-8 production in lungs, as revealed by immunohistochemical analysis. An anti-IL-8 antibody treatment almost completely prevented pulmonary edema, destruction of pulmonary architecture, and impairment in gas exchange as well as neutrophil infiltration in lungs; there was also a significant reduction in the rate of acute lethality. These results provide evidence that IL-8 has a pivotal role in the induction of ARDS associated with endotoxemia, probably by recruiting and activating neutrophils locally.

Animals↗
PubMed1997

Surgical outcome of microscopic vasectomy reversal: an analysis of 30 cases.

The results of 30 consecutive microscopic vasovasostomy procedures performed at a single institution over a five-year period between 1991 and 1995 were reviewed. When the surgical outcomes of patients who were operated on less than five years after their vasectomy were compared with the outcomes of those patients who received a vasovasostomy more than five years after their vasectomy, decreases in technical success rates were observed as measured by appearance of sperm in ejaculate (56% vs. 36%), biologic recovery as measured by mean sperm counts (56 million vs. 35 million) and mean progressive sperm motility (44% vs. 21%), along with a decrease in clinical success, as measured by overall pregnancy rates (50% vs. 7%, p < 0.05). Therefore, a microscopic vasovasostomy within 5 years of a vasectomy is a favorable procedure for vasectomy reversal.

Adult↗
PubMed1997

Comparison of cilostazol with warfarin as antithrombotic therapy after femoro-popliteal bypass surgery using an ePTFE graft.

BACKGROUND: Cilostazol (6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4- dihydro-2(1H)-quinolinone) is a new antiplatelet agent with a vasodilating action. The purpose of this study was comparison of cilostazol with warfarin as antithrombotic therapy after femoro-popliteal bypass surgery using an expanded polytetrafluorethylene (ePTFE) graft. EXPERIMENTAL DESIGN: This report is a retrospective study and the patients were followed up for five years. SETTING: Outpatients of university hospital. METHODS: Sixteen arteriosclerosis obliterans patients, who were diagnosed as having only superficial femoral artery stenosis or occlusion, underwent femoro-popliteal (above the knee) bypass using an ePTFE graft 6 mm in diameter. Cilostazol (150-200 mg/day) was administered to 6 cases (9 bypasses), and warfarin (prothrombin time was controlled to 15-25%.) was administered to 10 cases (14 bypasses). RESULTS: No clinically characteristic differences were found between the two groups. The cumulative 1-, 3-, and 5-year primary and secondary graft patency rates were 69% and 80%, 69% and 80%, and, 69% and 80% in the cilostazol group, vs 61% and 91%, 51% and 91%, and, 51% and 91% in the warfarin group, respectively. These differences were not significant (p < 0.05). No hemorrhage complications were observed in the cilostazol group. The management of cilostazol administration was safe and simple. CONCLUSIONS: Although the number of cases was small in this study, cilostazol was considered to be as effective as warfarin and suitable for the postoperative antithrombotic therapy after the ePTFE bypass surgery.

Aged↗
PubMed1996

Highly sensitive and simple liquid chromatographic determination in plasma of B6 vitamers, especially pyridoxal 5'-phosphate.

A simple and sensitive high-performance liquid chromatographic method for measuring the major vitamers of vitamin B6, i.e. pyridoxal and pyridoxal 5'-phosphate (PLP), and 4-pyridoxic acid (4-PA) in plasma was developed. The vitamers and 4-PA from plasma were extracted with 0.8 mol/l perchloric acid. The separation by HPLC is accomplished using an ODS reversed-phase column and a mobile phase of 0.1 mol/l potassium dihydrogen phosphate containing 0.1 mol/l sodium perchlorate, 0.5 g/l sodium bisulfite adjusted to pH 3, at a flow-rate of 1.0 ml/min. The vitamers and 4-PA were eluted within 13 min and their concentration is determined with a fluorometric detector (excitation, 300 nm; emission, 400 nm). In this method, PLP in plasma can be determined with high sensitivity using derivatization with sodium bisulfite in the mobile phase.

Animals↗
PubMed1996

Evidence of HTLV-I in thyroid tissue in an HTLV-I carrier with Hashimoto's thyroiditis.

Human T-lymphotropic virus type l (HTLV-I) protein and messenger RNA (mRNA) for HTLV-I were examined in thyroid tissues from two patients with Hashimoto's thyroiditis and serum anti-thyroid antibody. The virus envelope protein and signals for the mRNA were detected in many of the follicular epithelial cells of the thyroid tissue from one of the patients, respectively, by immunohistochemistry and in situ hybridization. PCR-Southern blotting revealed the presence of HTLV-I DNA in the thyroid tissue, in which the viral protein and mRNA were detected, although no virus particles were found in the epithelial cells by electron microscopy. HTLV-I virus was not present in the thyroid tissue from the second patient. The present findings suggest that infection of thyroid tissue with HTLV-I is associated with the pathogenesis of Hashimoto's thyroiditis in some patients.

Base Sequence↗
PubMed1996

High frequencies of human T-lymphotropic virus type I (HTLV-I) infection and presence of HTLV-II proviral DNA in blood donors with anti-thyroid antibodies.

To investigate the relationship between human T-lymphotropic virus (HTLV) types I and II and the pathogenesis of autoimmune thyroid diseases, we examined serum anti-thyroid antibodies in 1019 blood donors with or without serum anti-HTLV-I antibody as well as proviral DNA for HTLV-II in leukocyte DNA by the polymerase chain reaction in 395 blood donors with or without anti-thyroid antibodies. The frequency of donors with anti-HTLV-I antibody who also showed anti-thyroid antibodies (7.9%) tended to be higher than that (6.3%) among donors who did not have the anti-HTLV-I antibody. The frequency of anti-thyroid antibodies in 125 young male donors aged 16-39 years with anti-HTLV-I antibody (4.8%) was significantly higher (P < 0.05) than that (0.6%) in 164 control donors without the antibody. In blood donors with anti-thyroid antibody, 25.0% of those with anti-HTLV-I antibody and 14.3% of those without the antibody had HTLV-II proviral DNA. In contrast, in donors without anti-thyroid antibody HTLV-II proviral DNA was detected in 2.3% of those with anti-HTLV-I antibody and in 0.6% of those without the antibody. Thus the detection rates in donors with anti-thyroid antibody were significantly higher (P < 0.001) than those in donors without the antibody, regardless of HTLV-I infection. These results suggest that HTLV-I infection and the presence of HTLV-II proviral DNA may be independently related to the pathogenesis of autoimmune thyroid diseases.

Adolescent↗