Different alterations of nuclear triiodothyronine receptor capacity in liver and kidney induced by starvation and triiodothyronine administration

Many studies have shown alterations in the number of nuclear triiodothyronine receptor (NT3R) under pathophysiologic situations. Most of these studies were performed on the rat liver and it is not known whether NT3R in different tissues exhibits an alteration similar to that in the liver. We compared the change of nuclear receptor capacity for T3 in the liver and kidney during starvation and after T3 injection. Fasting for 72 h decreased maximal binding capacity (Cmax) in the rat liver receptor to 67% of the control, while it did not significantly change Cmax in the kidney. These changes in Cmax were parallel to those of nuclear protein concentrations in both tissues. Daily sc injection of T3 (20 micrograms/100 g body weight) for 3 days also caused the different alteration of Cmax in the liver and kidney. After T3, hepatic NT3R increased to 182% of the control, but renal NT3R increased only to 136%. Association constants were the same in all groups. These results show that changes of NT3R capacity under some conditions vary in different tissues.     

Possible involvement of active oxygen species in selenite toxicity in isolated rat hepatocytes

Mechanisms of selenite cytotoxicity were examined using isolated rat hepatocytes. When selenite was added to a suspension of rat hepatocytes, intracellular reduced glutathione (GSH) was decreased and the oxygen consumption rate was increased. Subsequently, thiobarbituric acid-reactive substances (TBA-RS) and lactate dehydrogenase (LDH) leakage were increased. A ferric iron chelator, desferrioxamine (DF), and a synthetic Superoxide dismutase (SOD) mimic, desferrioxamine manganese (DFMn), reduced the selenite toxicity. These results suggest that Superoxide anion and its reactive metabolites such as the hydroxyl radical may be involved in the cytotoxicity of selenite.     

Changes in distribution of mercury and selenium in soluble fractions of rabbit tissues after simultaneous administration

The existing states of mercury and selenium in the blood and in soluble fractions of perfused rabbit liver and kidney were studied by gel filtration on Sephadex G-200 1 hr or 24 hr after intravenous injection of mercuric chloride and/or sodium selenite. Both mercury and selenium in the plasma and stroma-free hemolysate were found to exist in the high-molecular weight fraction following simultaneous injection of mercuric chloride and sodium selenite. Patterns in gel filtration of the plasma and the stroma-free hemolysate did not show any significant change between 1 hr and 24 hr after the administration. A similar tendency as described above was obtained with the liver-soluble fraction at 24 hr after injection of mercuric chloride and sodium selenite. A possible role of the high-molecular weight complex, which is quickly formed by the interaction of mercury and selenium in blood stream, in decreasing the acute renal toxicity of inorganic mercury is discussed.     

Hypothalamic hypothyroidism due to isolated thyrotropin-releasing hormone (TRH) deficiency

Cold intolerance and secondary amenorrhea developed in a patient who had meningoencephalitis 4 yr prior to study. A clinical diagnosis of hypothalamic hypothyroidism was made on the basis of low serum thyroxine and triiodothyronine levels, and low plasma thyrotropin concentrations, which were responsive to thyrotropin-releasing hormone (TRH). The secretion of the remaining pituitary hormones (growth hormone, prolactin, adrenocorticotropin and gonadotropins) was intact. Not only was thyroid function normalized by oral administration of TRH, but also menses resumed after adequate replacement therapy with thyroid hormone. These results imply that hypothyroidism in this patient was due to isolated dysfunction of hypothalamic TRH release.     

Acromegaly: insensitivity of the pancreatic alpha cell to hyperglycaemia.

Plasma glucagon levels were determined after 50 g of oral glucose loading in eleven acromegalics and fourteen normal subjects. Basal plasma glucagon levels were significantly elevated in patients with acromegaly, as compared with those in normal subjects. Oral glucose loading caused a decrease in plasma glucagon in normal subjects but not in acromegalics. Since this non-suppressibility of plasma glucagon by orally administered glucose was observed even in acromegalics without diabetes, it is concluded that insensitivity of the pancreatic alpha cell to hyperglycaemia exists in patients with acromegaly as well as in diabetics.     

A comparison of perioperative factors with two methods of coronary artery bypass grafting (CABG): off-pump and conventional

BACKGROUND: The safety and efficiency of off-pump coronary artery bypass grafting (OPCAB) are still controversial. The purpose of this study was to evaluate this approach in comparison with the conventional cardiopulmonary bypass technique (cCABG). METHODS: A retrospective review of patients who had undergone coronary artery bypass grafting independently without other operations between January 1, 1999 and September 30, 2001 was performed. The patients were divided into two groups: those who underwent OPCAB and the remainder for cCABG. The perioperative factors of the two groups were compared. RESULTS: A total of 152 OPCAB and 142 cCABG cases were reviewed. Compared with cCABG, OPCAB significantly reduced the amount of catecholamine needed on admission to ICU, intubation time, overall hospital length of stay, and neurologic events. There were also trends for decreases in ICU length of stay, mortality, and renal failure. On the other hand, OPCAB did not affect perioperative blood loss. CONCLUSIONS: Overall OPCAB is safer and more efficient than cCABG. However, we have to note in anesthetic management that OPCAB does not reduce blood loss.     

GFAP-expressing progenitors are the principal source of constitutive neurogenesis in adult mouse forebrain

Establishing the cellular identity in vivo of adult multipotent neural progenitors is fundamental to understanding their biology. We used two transgenic strategies to determine the relative contribution of glial fibrillary acidic protein (GFAP)-expressing progenitors to constitutive neurogenesis in the adult forebrain. Transgenically targeted ablation of dividing GFAP-expressing cells in the adult mouse subependymal and subgranular zones stopped the generation of immunohistochemically identified neuroblasts and new neurons in the olfactory bulb and the hippocampal dentate gyrus. Transgenically targeted cell fate mapping showed that essentially all neuroblasts and neurons newly generated in the adult mouse forebrain in vivo, and in adult multipotent neurospheres in vitro, derived from progenitors that expressed GFAP. Constitutively dividing GFAP-expressing progenitors showed predominantly bipolar or unipolar morphologies with significantly fewer processes than non-neurogenic multipolar astrocytes. These findings identify morphologically distinctive GFAP-expressing progenitor cells as the predominant sources of constitutive adult neurogenesis, and provide new methods for manipulating and investigating these cells.     

Phase I trial of carboplatin and weekly paclitaxel in patients with advanced non-small-cell lung cancer

OBJECTIVE: This study was designed to determine the maximum tolerated dose of paclitaxel administered weekly in combination with carboplatin and to assess its dose limiting toxicity and preliminary activity in patients with previously untreated, advanced non-small-cell lung cancer. METHODS: Carboplatin was administered at a fixed dose that maintained an area under the curve of 6. Paclitaxel was given over 1 h once a week for 3 weeks starting at 60 mg/m(2) and escalated in 10 mg/m(2) increments. RESULTS: Twenty-one patients were treated with six dose levels (60, 70, 80, 90, 100, 110 mg/m(2)) of paclitaxel. The dose limiting toxicity was infection and the maximum tolerated dose was 110 mg/m(2). Nine of 21 (42.9%) patients demonstrated a therapeutic response. CONCLUSION: Weekly paclitaxel and carboplatin were well tolerated. Based on our results, 100 mg/m(2) of paclitaxel for 3 weeks of a 4-week cycle, in combination with carboplatin, was recommended for a phase II study.