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Biomedical subjects

J Hayashi

Publications and source records attributed to J Hayashi.

At least 523 records · Page 29Linked to original sources
PubMed1976

A basic study of the Hanssen technique for evaluation of single nephron glomerular filtration rate.

The purpose of this study was mainly to examine some basic problems of the Hanssen technique for the evaluation of single nephron glomerular filtration rate (SNGFR). Firstly, experiments were performed using Wistar rats to determine the amount of C14-ferrocyanide necessary to give sufficient C14 radioactivity in dissected nephrons. Using 200 muCi of C14-ferrocyanide, the samples of dissected nephrons provided only twice as much as background. Hence, we chose the amount of 600 to 700 muCi of C14-ferrocyanide for each rat in the later experiments, which yielded the radioactivity 5 to 6 times as much as background. Secondly, the homogeneity of intrarenal C14-ferrocyanide distribution was tested. Five superficial (SUP) and juxtamedullary (JM) proximal tubules four different regions were dissected and the radioactivity of those nephrons was counted. The distribution of C14-ferrocyanide in each piece was representative of the overal distribution. The summary of morphologic and clearance studies were as follows. The mean lengths of proximal tubules of 40 SUP nephrons, 5.3 +/- 0.2 mm, and 39 JM nephrons, 6.3 +/- 0.1 mm, were significantly different (P less than 0.01). The mean glomerular diameter of the JM nephrons, 110 +/- 2.7 mu, was significantly greater than that of the SUP nephrons, 95 +/- 3.1 mu (P less than 0.01). The mean SNGFR of 129 SUP nephrons, 23.4 +/- 4.2 nl/min/100g Body Weight (BW), and that of 130 JM nephrons, 34.5 +/- 5.1 nl/min/100g BW, were significantly different (P less than 0.01). The ratio of superficial/juxtamedullary nephron glomerular filtration rate (S/JM Ratio) was 0.85 +/- 0.02. We conclude that C14-ferrocyanide is regularly distributed to the kidney and that it is necessary to infuse sufficient amount of C14-ferrocyanide in this technique.

Animals↗
PubMed1975

Transplantable adenocarcinomas from color-rectal tumors induced by infusion of N-methyl-N'-nitro-N-nitrosoguanidine in ACI/N rats.

Two transplantable strains of adenocarcinoma were established from the carcinomas of the colon and rectum induced by infusion of N-methyl-N'-nitro-N-nitrosoguanidine in inbred ACI/N rats, The tumors are solid type, not converted to ascite form yet, either papillary or tubulo-papillary adenocarcinomas, and particularly grow slowly, showing 2 to 4 months of survival in animals transplanted subcutaneously. Besides histological resemblance of the tumors to human adenocarcinoma of the large intestine, marked mucin production in tumor was noted in one of these strains.

Adenocarcinoma↗
PubMedDate not supplied

Human lymphoblastoid interferon treatment for patients with hepatitis C virus-related cirrhosis.

To evaluate the efficacy and safety of human lymphoblastoid interferon treatment (interferon alfa) for patients with compensated cirrhosis caused by hepatitis C virus (HCV) infection, we randomly assigned 82 cirrhotic patients with chronic HCV infection (44 men, 38 women; mean age, 58.6 years) to two groups: 41 patients were treated with interferon alfa (480 million U over 6 months), and the other patients received no drug treatment. HCV RNA genotypes were determined by polymerase chain reaction (PCR) testing using type-specific primers. HCV RNA levels were measured by competitive PCR testing. No untreated patients eliminated HCV RNA from the serum or had a decrease in the level of alanine aminotransferase to normal during the observation period. Of the 34 patients who completed interferon alfa treatment, 6 (17.6%) who were considered complete responders eliminated HCV RNA from the serum by the end of treatment and sustained this elimination throughout a 6-month follow-up period. Complete responders constituted 6 (46.2%) of 13 patients with HCV RNA levels < or = 10(5) copies/50 microL, but none of the 21 patients with levels > 10(5) copies/50 microL were complete responders. Two (7.1%) of 28 patients with genotype 1b infection and 4 (66.7%) of 6 with genotype 2a were complete responders. Five patients withdrew because of interferon alfa-induced side effects (1 for thrombocytopenia, 3 for severe general malaise, and 1 for impotence), and 2 withdrew after being diagnosed with hepatocellular carcinoma. Hepatic failure did not occur in any treated patient in the present study. These findings indicate that interferon alfa treatment is useful for compensated cirrhosis caused by HCV infection if the HCV RNA levels are low and the infection is of genotype 2a.

Aged↗
PubMedDate not supplied

Development of an endocardioscope for repair of an atrial septal defect in the beating heart.

The purpose of this study was to evaluate the possibility of surgical treatment of an atrial septal defect in the beating heart without cardiopulmonary bypass. The first step was to develop an endocardioscope that permitted observation of the inside of the beating heart. To visualize the inside of the beating heart, the tip of the endoscope was covered with a glass adapter. The endocardioscope was inserted through the right atrial appendage in eight beagles. The atrial septum, foramen ovale, coronary sinus, tricuspid valve, and chordae tendineae were identified without hemodynamic derangement. The second step was to attempt to close the foramen ovale with clips or staplers. We were able to close the foramen ovale with these devices, but a safer, easier device is needed. The endocardioscope we developed should prove to be a useful tool for minimally invasive surgical treatment of heart diseases, such as atrial septal defect.

Animals↗
PubMedDate not supplied

Direct cardiac potential trigger for chronic control of a ventricular assist device.

As a new trigger method for chronic drive control of a ventricular assist device (VAD), a direct cardiac potential trigger was assessed under various conditions in a chronic experimental model. A pneumatic pulsatile VAD was implanted as circulatory support between the left ventricular apex and the ascending aorta in 12 adult pigs. Hemodynamic parameters and pump output were continuously monitored. Two tips of a bipolar electrode were set on the RV anterior wall and the LV posterior wall for recording direct cardiac potential. Counterpulsation drive of the VAD was applied by using the R wave in a standard electrocardiogram (ECG) or the direct cardiac potential as an ECG trigger. As special conditions, various artifacts on ECG, electromusculogram, arrhythmia, irregular ventilation, and passive vibration (simulation of exercise) were set for assessing the ECG trigger modes. Artifacts of irregular ventilation and passive vibration made the drive control poor using a standard ECG trigger. In contrast, the direct cardiac potential trigger maintained the counterpulsation control of the VAD well in all conditions of this study, and was a safe and reliable support for the native heart. It also supported animals for up to 48 hours after operation. The above results suggested that the direct cardiac potential trigger might be useful for monitoring native heart beats and adjusting the support cycle to the native heart cycle as a chronic control method for various VADs.

Animals↗
PubMedDate not supplied

The influence of a heparin-coated oxygenator during cardiopulmonary bypass on postoperative lung oxygenation capacity in pediatric patients with congenital heart anomalies.

BACKGROUND: Cardiopulmonary bypass (CPB) causes an inflammatory response and remarkably depresses the oxygenation capacity of the lung in pediatric patients with pulmonary hypertension. Although a heparin-coated circuit is more biocompatible than an uncoated circuit, the beneficial effect of a heparin-coated circuit on the postoperative lung function in the pediatric patients remains unknown. METHODS: Sixty patients younger than 3-years-old undergoing heart operations for ventricular septal defect were divided into three groups: group I = children (n = 11) without pulmonary hypertension who underwent CPB with an uncoated oxygenator; group II = children (n = 32) with pulmonary hypertension who underwent CPB with an uncoated oxygenator; and group III = children (n = 17) with pulmonary hypertension who underwent CPB with a heparin-coated oxygenator. A respiratory index (RI) was used to assess the oxygenation capacity of the lung. RESULTS: RI in group II was significantly higher than in group I and intubation time in group II was significantly longer than in group I. There was a positive correlation between preoperative pulmonary-systemic blood pressure ratio and RI at 3 hours post-CPB. Three and six hours post-CPB, RI in group III was significantly lower than in group II, but there was no significant difference in RI between both groups at 12 hours post-CPB. CONCLUSIONS: Pulmonary hypertensive pediatric patients were vulnerable to postperfusion lung injury. Beneficial effects of a heparin-coated oxygenator in a CPB circuit was limited to the early hours post-CPB and the postoperative clinical course was not modified by the heparin-coating of a membrane oxygenator.

Cardiopulmonary Bypass↗
PubMedDate not supplied

Neutrophil elastase inhibitor ameliorates reperfusion injury in a canine model of lung transplantation.

BACKGROUND: We investigated the effects of neutrophil elastase inhibitor ONO-5046 Na on lung ischemia-reperfusion injury in a canine model of single lung transplantation. METHODS: 24 mongrel dogs, 12 donors and 12 recipients, were used for single lung transplantation. Lung grafts were preserved for 18 h by cold ischemia then transplanted into the left thoracic cavity of recipients. In 6 recipients (ONO group), a bolus of ONO-5046 Na (10 mg/kg) was introduced before reperfusion and followed by continuous infusion (10 mg/kg/h). The remaining 6 recipients (control group) did not receive ONO-5046 Na and thus served as controls. We evaluated lung function and respiratory parameters over 240 min. RESULTS: The total cell number in bronchoalveolar lavage fluid increased significantly in the control group in comparison to that in the ONO group. Histologic scores after 4 h of reperfusion and myeloperoxidase activity were significantly lower in the ONO group than in the control group. CONCLUSION: Neutrophil elastase inhibitor ONO-5046 Na may be useful in ameliorating lung reperfusion injury after transplantation.

Animals↗
PubMedDate not supplied

The effectiveness of anti-retroviral drug therapy for HIV-1 is associated with HIV-1 proviral DNA levels and viral selection.

The effect of combination anti-retroviral therapy regimens on HIV-1 proviral DNA levels in peripheral blood mononuclear cells was examined in 12 HIV-1-positive patients, using endpoint dilution polymerase chain reaction and serial cloning, and sequencing of the gag region of HIV-1. The major clone was defined as the most numerous of 10 analysed clones, and observation periods ranged from 8 months to 32 months (mean 19.7 +/- 10.2 months). In five patients (one with primary-stage HIV-1 infection) receiving three anti-retroviral drugs, HIV-1 RNA reduced to undetectable levels (i.e. < or = 100 copies/ml). HIV-1 proviral DNA and the number of major clones reduced in four of these patients. HIV-1 RNA levels reduced, but remained detectable, in five other patients. In the two remaining patients (both receiving two rather than three anti-retroviral drugs), HIV-1 RNA levels increased. These results suggest that the population of major clones may be affected when HIV-1 RNA levels reduce following combination regimens of anti-retroviral therapy.

Adult↗
PubMedDate not supplied

Human lymphoblastoid and fibroblast interferon in the treatment of chronic hepatitis B.

Twenty-six patients, positive for hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), hepatitis B virus (HBV)-deoxyribonucleic acid (DNA), and DNA polymerase activity, were treated with human lymphoblastoid interferon (IFN-alpha) or human fibroblast interferon (IFN-beta) after enoxolone glycoside (glycyrrhizinic acid), given for four weeks and then withdrawn. The interferons were given continuously for four weeks. Four months after the treatment, six of 12 patients treated with IFN-alpha were both HBeAg-negative and HBV-DNA-negative while three of 14 patients treated with IFN-beta were HBV-DNA-negative and one was HBeAg-negative. None of the ten untreated control patients became negative for either HBeAg or HBV-DNA. All patients studied remained HBsAg-positive. Both interferons were generally well tolerated. A persistent low-grade fever was reported by more patients in the IFN-beta group and hair and weight loss were more common in the IFN-alpha group. The results indicate that the combination of enoxolone glycoside withdrawal and IFN-alpha treatment reduces HBV replication more effectively than does interferon alone.

Adolescent↗