Investigation of the renal injury caused by liver ischemia-reperfusion in rats

To explain the mechanism of renal injury caused by liver ischemia-reperfusion, we investigated biochemical and morphological changes in the liver and kidney in rats. After reperfusion following 60 min of liver ischemia, numerous changes were found. The level of serum transaminases and lipid peroxide formation in the liver tissue increased significantly. Electron microscopic studies revealed that most of the hepatocytes had swollen mitochondria and clumping of the nuclear chromatin. The sinusoidal endothelium was disrupted and the sinusoidal lumen was filled with numerous erythrocytes. Blood endotoxin concentration, plasma lipid peroxide levels, and serum -glucuronidase activities were significantly higher than in the control group. Biochemical and morphological renal injury was also observed. Tissue lipid peroxide levels increased in both the kidney and the liver. Microscopic examination revealed damage to the renal tubules, including interstitial edema, dilatation of the lumen, and granular casts derived from necrotic cells in the proximal convoluted tubule. The levels of urinary N-acetyl--d-glucosaminidase (NAG) in the liver ischemia-reperfusion group were also higher than in the control group. These results suggest that the renal injury was caused by an increase in endotoxin, lipid peroxide, and lysosomal enzymes in the blood following the liver injury induced by the ischemia-reperfusion.     

Cytotoxic Mechanisms of FK317, a New Class of Bioreductive Agent with Potent Antitumor Activity

FK317 is a member of a new class of bioreductive agents that exhibit strong cytotoxicity against various human cancer cells. The effect of FK317 was found to be stronger than that of mitomycin C (MMC), adriamycin (ADR) or cisplatin (CDDP). Alkaline elution analysis indicated that FK317 formed interstrand DNA-DNA and DNA-protein cross-links in cells. On the other hand, no DNA single-strand breaks were observed in the cells treated with FK317. In a cell-free system the deacetylated metabolites produced cross-linked DNA under reductive conditions, though FK317 itself did not form DNA-DNA cross-links. In order to elucidate the metabolic activation mechanisms, we established an FK317-resistant subline from human non-small cell lung cancer cells (Lu99) by stepwise and brief exposure (1 h) to FK317. The resistant subline (Lu99/317) showed cross-resistance to MMC and carboquone (CQ), but not to ADR or CDDP. DT-diaphorase, which is one of the activation enzymes of MMC and CQ, was deficient in Lu99/317 cells as determined by enzyme activity assay. However, the levels of NADPH:cytochrome P450 reductase, which is another activation enzyme for MMC and CQ, were comparable in resistant and parent cell lines. Treatment of the cells with dicumarol, an inhibitor of DT-diaphorase, reduced the cytotoxicity of FK317 to Lu99 cells, but not to Lu99/317 cells. These results indicate that deacetylation of FK317 is necessary for its reductive activation, and deacetylated FK317 is reduced by DT-diaphorase to form an active metabolite, which produces DNA-DNA interstrand and DNA-protein cross-links that lead to cell death.     

Blockade of menstrual cycle by thyroidectomy in Japanese monkeys (Macaca fuscata fuscata)

To examine the role of thyroid hormones in the seasonal breeding cycle in Japanese monkeys (Macaca fuscata fuscata), sexually mature females were thyroidectomized (n=6) in early December, during the midbreeding season, or they received sham operations (n=4). They were housed indoors individually, and blood samples were collected two to three times a week to monitor gonadotropin and gonadal steroid hormone secretions. Control monkeys exhibited ovulatory cycles during the breeding season. The mean dates of onset and end of the ovulatory cycles were October 22±13 d and February 25±14 d, respectively. These dates coincided well with those of our colonies under captivity. By contrast, three of the six thyroidectomized monkeys terminated ovulatory cycles immediately after operations; the remaining three monkeys ovulated only once or twice after thyroid removal. The mean dates of onset and end of the ovulatory cycles of thyroidectomized monkeys were October 18±4 d and December 31±4 d, respectively. This was a significantly earlier termination of the ovulatory cycles than in controls. Mean concentrations of plasma thyroxine of control monkeys were maintained throughout the experimental period, whereas plasma thyroxine concentrations of thyroidectomized monkeys decreased abruptly to undetectable levels. Thyroidectomized monkeys exhibited significantly higher levels of plasma prolactin (PRL) than controls. Moreover, even in control monkeys, plasma PRL increased during the transition out of the breeding season. These results suggest that thyroid hormones play an important role in the regulation of ovulatory cycles in Japanese monkeys, directory or indirectly, possibly by mediating the changes of PRL secretion.     

Prediction of maximal cardiac output in preoperative patients with coronary artery disease

Of 100 patients (89 men, 11 women) studied preoperatively to determine their aerobic and hemodynamic profiles at rest and during upright treadmill exercise. The mean maximal cardiac output (CO), measured using the direct Fick principle, was 57 ± 14% of average normal values. The reduction in maximal heart rate (63 ± 13% of normal) was a greater factor in the reduction in CO than stroke volume (88 ± 16% of normal). Maximal oxygen consumption (V?O₂max) was 48 ± 15% of normal and the greater reduction in V?O₂₂max compared with CO was due to lower peripheral extraction in the coronary patients. Variables that correlated with maximal CO in a univariate analysis included angina severity (r = ?0.45), V?O₂₂max (r = 0.67), maximal heart rate (r = ?0.31), left ventricular dysfunction (r = ?0.45), maximal systolic blood pressure (r = ?0.31) and number of vessels with ≥ 50% diameter reduction (r = ?0.3). Resting ejection fraction did not correlate with maximal CO. In a multivariate analysis, 4 variables correlated significantly (r = 0.77) with maximal CO: in order, V?O₂₂max, number of vessels with ≥ 50% stenosis, magnitude of ST depression and sex.     

Differential effects of FK506 and methotrexate on inflammatory cytokine levels in rat adjuvant-induced arthritis

OBJECTIVE: To investigate the effects of prophylactic and therapeutic treatments with FK506 (tacrolimus), an immunosuppressive drug that specifically inhibits T cell activation, and methotrexate (MTX) on inflammatory cytokines, tumor necrosis factor (TNF)-a, interleukin (IL)-1beta, and IL-6 levels in rat adjuvant-induced arthritis (AIA). METHODS: AIA was induced in female Lewis rats. Arthritis was assessed by hindpaw swelling. TNF-a, IL-1beta, and IL-6 levels in paw extracts were determined by ELISA. To assess the effects on cytokine levels, rats were treated prophylactically with FK506 (3 mg/kg) or MTX (0.1 mg/kg) from day 1 to day 17, and therapeutically with FK506 (5 mg/kg) or MTX (1 mg/kg) from day 15 to day 17 (3-day treatment) or day 15 to 20 (6-day treatment) by oral administration. RESULTS: TNF-a, IL-1beta, and IL-6 levels in paw tissue were found to significantly increase between day 15 and day 21 after adjuvant injection, when the arthritis was in a developed stage. Prophylactic treatment with FK506 and MTX suppressed arthritis and reduced the levels of those inflammatory cytokines. FK506 caused a marked reduction of TNF-a and IL-1beta levels in paw tissue even in short-term (3-day) therapeutic treatment. It reduced all levels of TNF-a, IL-1beta, and IL-6 in paws in 6-day therapeutic treatment. In contrast, therapeutic treatment with MTX affected neither TNF-a or IL-6 levels in paws. MTX reduced IL-1beta levels only in the 6-day treatment. CONCLUSION: FK506 is more effective than MTX in reducing elevated levels of inflammatory cytokines TNF-a, IL-1beta, and IL-6 in established stages of AIA. Our findings suggest that inhibition of T cell activation results in a rapid reduction of inflammatory cytokine levels even after the arthritis is established in AIA.     

Hyperthyrotropinemia at 2 weeks of age indicates thyroid dysfunction and predicts the occurrence of delayed elevation of thyrotropin in very low birth weight infants

Background For preterm infants, transient hypothyroxinemia of prematurity and transient primary hypothyroidism, especially with delayed elevation of serum thyrotropin (TSH), are important. Methods To address the above two issues, we performed thyrotropin‐releasing hormone (TRH) stimulation tests at about 2 weeks of age for 31 preterm infants with a gestational age of 30 weeks or less. Results For basal TSH levels, 68% of infants (21 of 31) showed normal values (TSH < 10 mU/l) and 32% of infants (10 of 31) showed higher values (four infants: TSH 10–15 mU/l, six infants: TSH > 15 mU/l). Peak TSH values in response to TRH stimulation tests ranged from 9·76 to 114·8 mU/l. All infants showed a significant response to TRH stimulation tests. Only 9·5% of infants (two of 21) with normal basal TSH values showed a hyperresponse (peak TSH > 45 mU/l), whereas 80% of infants (eight of 10) who had higher basal TSH values showed a hyperresponse. All infants who showed mildly elevated basal TSH values (TSH 10–15 mU/l) and a hyperresponse to TRH stimulation tests showed delayed elevation of basal TSH values (TSH > 15 mU/l) later. Conclusions Thyrotropin‐releasing hormone stimulation tests at about 2 weeks of age suggested that the hypothalamic–pituitary–thyroid axis might be established even in extremely premature infants. Basal increased TSH levels (TSH > 10 mU/l) and a hyperresponse to TRH stimulation tests (peak TSH > 45 mU/l) suggested subclinical thyroid dysfunction. Serum TSH values at about 2 weeks of age could be useful for the prediction of delayed TSH elevation.     

Relationship of physical distress to dizziness in patients with fibromyalgia

Conclusions: The feelings of dizziness and unsteadiness of the patients with fibromyalgia supposed specifically amplified by the hypersensitivity mechanism of CSS (central sensitivity syndrome) of them. The severity of subjective pain and physical distress according to the questionnaires were not correlated with the objective body sway on the stabilometer. Objectives: Fibromyalgia manifests primarily as chronic pain of the entire body, but is also often associated with a variety of physical symptoms including dizziness and unsteadiness. This study assessed whether objective measures of body sway and unsteadiness of them are associated with their subjective dizziness findings. Method: Subjects were 24 patients diagnosed with fibromyalgia, but one patient who had the past history of sudden deafness was excluded. The 23 patients were assessed by a stabilometer as the objective measures of body sway, and JFIQ (Japanese version of the fibromyalgia impact questionnaire), DHI (dizziness handicap inventory) and ABC (activities-specific balance confidence) as the subjective questionnaires. Results: The significant correlations were shown between the scores of JFIQ and DHI, JFIQ and ABC, and DHI and ABC. Then, the body sway index of stabilometer environmental area was significantly correlated with DHI score. However, the stabilometer index was not correlated neither with JFIQ or ABC.