Acute pulmonary toxicity of inhaledβ-1,3-glucan and endotoxin

The number of inflammatory cells was studied in lung walls and airways after inhalation of endotoxin or -1,3-glucan. In the water unsoluble form, -1,3-glucan caused a delayed response in terms of a decrease in macrophages and lymphocytes in the lung wall, 1 to 7 days after exposure but no invasion of neutrophils into the airways. When solubilized in 0.02 N NaOH, the cell response was the same as that observed after exposure to endotoxin.     

Grading score system: A method for evaluation of the degree of senescence in Senescence Accelerated Mouse (SAM)

For evaluation of the degree of senescence in SAM-P, accelerated senescence prone mouse, formerly called SAM or prone series or P-series, consisting of SAM-P/1, SAM-P/2, SAM-P/3 and SAM-P/4 corresponding to P-1, P-2, P-3 and P-4 series, respectively, in the previous reports, and in SAM-R, accelerated senescence resistant mouse, formerly called resistant series or R-series, consisting of SAM-R/1, SAM-R/2 and SAM-R/3 corresponding to R-1, R-2 and R-3 series, respectively, in the previous reports, the grading score system was adopted. The items to be examined in this system include 11 categories selected from the clinical signs and gross lesions considered to be associated with the aging process. The degree of the senescence in each category was graded from 0 to 4 according to the detailed criteria devised in our laboratory. After 8 months of age each mouse was examined every 4 months, and some of the mice were examined after 2 months of age.In almost all categories, the grading score and incidence began to increase from 4 or 6 months of age and continued to increase with advancing age in both SAM-P and SAM-R. The increase, however, was more marked in SAM-P than in SAM-R. The slow but steady increase in the SAM-R levelled out at 24 months of age and was comparable to that of 12 months of age in SAM-P. In both SAM-P/1 at 8 months of age and SAM-R/2 at 12 months of age, there was a significant reverse correlation between total score of this grading score system and length of residual life after examination.Systematic and extensive studies using the grading score system showed that if the validity of the system is, based on “irreversibility” and “universality” of the changes in     

Modifying effects of 1'-acetoxychavicol acetate (ACA) and the novel synthetic retinoids Re-80, Am-580 and Am-55P in a two-stage carcinogenesis model in female rats

Effects of dietary administration of 1'-acetoxychavicol acetate (ACA) and the novel synthetic retinoids 4-[1-hydroxy-3-oxo-3-(5,6,7,8-tetrahydro-3-hydroxy-5,5,8,8-tetramethyl-2-naphthalenyl)-1-propenyl]benzoic acid (Re-80); 4-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)carboxamido]benzoic acid (Am-580); and 6-[(3,5-di-tert-butylphenyl) carbamoyl]nicotinic acid (Am-55P) were examined using a two-stage rat carcinogenesis model. A total of 190 female SD rats was treated sequentially with 1,2-dimethylhydrazine (DMH, s.c.); 7,12-dimethylbenz(a)anthracene (DMBA, i.g.); and 2,2'-dihydroxy-di-n-propylnitrosamine (DHPN, in the drinking water) during the first three weeks (DDD-initiation), and an additional 60 rats received the vehicle alone (non-initiation). One week after the completion of the initiation period, they were divided into nine groups and administrated Re-80 (at dose levels of 1.0 or 0.4 ppm), Am-580 (20 or 4 ppm), Am-55P (20 ppm), ACA (100 ppm), all-trans-retinoic acid (10 or 2 ppm) or no supplement in the diet for 33 weeks, until survivors were euthanatized at week 37 weeks. After DDD-initiation, all-trans-retinoic acid at the high dose delayed the development of mammary tumors. The multiplicity of colon tumors in the group fed Am-55P and the incidences of nephroblastomas with ACA or Am-580 were decreased as compared with the control values, but the other chemicals had no modifying effects on tumor development in any organs. Thus, among ACA and the novel synthetic retinoids tested, only Am-55P showed a weak inhibitory effect on a neoplasm of general interest under the present experimental conditions.     

Increase in oxidized NO products and reduction in oxidized glutathione in cerebrospinal fluid from patients with sporadic form of amyotrophic lateral sclerosis

To determine the role of free radical mechanisms in the pathogenesis of amyotrophic lateral sclerosis (ALS), cerebrospinal fluid concentrations of oxidized nitric oxide (NO) products (nitrite and nitrate) and reduced and oxidized forms of glutathione (GSH and GSSG, respectively) were compared between patients with the sporadic form of ALS (SALS) and controls. In the SALS patients, the nitrate levels were significantly higher (by 73%) in contrast to remarkably lower GSSG/GSH ratio, approximately 3-fold, compared to controls. These results suggest that NO production or oxidation is activated in SALS patients, leading to a decrease in superoxide radicals to oxidize GSH. The subsequent generation of a highly reactive anion, peroxynitrite, may play a causal role in the pathogenesis of SALS.     

The investigation of isoflurane therapy for status asthmaticus patients]

Status asthmaticus is defined as an attack of bronchial asthma that resists conventional treatment and continues for more than 24 hours. We report here about patients with status asthmaticus who were successfully treated with isoflurane inhalation. Of the 19 patients who were transferred to the intensive care unit (ICU) and underwent mechanical ventilation from January 1996 to May 2001, eleven patients who were first treated by isoflurane inhalation were targeted in this study. Their improvement was assessed 6 and 24 hours after anesthesia compared with their condition before anesthesia. The tidal volume, pH, and PaCO2 improved within 6 hours after anesthesia. For the next step, among the patients who were transferred to the critical care center soon after an attack of bronchial asthma and underwent mechanical ventilation, 8 patients who were treated by isoflurane inhalation anesthesia (Group I) and another 4 patients who were not treated by isoflurane (Group NI) were compared to assess the usefulness of isoflurane inhalation therapy. The patients in Group I stayed in the ICU and underwent mechanical ventilation for a shorter period. These patients had hypotension and liver dysfunction after the inhalation anesthesia, but these symptoms were improved by decreasing the concentration of isoflurane. Isoflurane inhalation therapy seemed useful for intractable status asthmaticus, and earlier introduction of this therapy is expected to achieve a greater therapeutic effect.     

Apoptotic body engulfment by a human stellate cell line is profibrogenic

Hepatocyte apoptosis and stellate cell activation are both features of chronic liver diseases, but a relationship between these events has not been explored. In macrophages, engulfment of apoptotic bodies induces expression of transforming growth factor-beta (TGF-beta), a profibrogenic cytokine. We examined whether a similar response occurs in stellate cells. Fluorescently labeled hepatocyte apoptotic bodies were added to cultures of primary and immortalized human stellate cells. Stellate cells, but not hepatocytes, readily engulfed apoptotic bodies in a time-dependent manner as assessed by confocal microscopy. The activation of primary and immortalized human stellate cells after incubation with apoptotic bodies, as well as their fibrogenic activity, was indicated by an increase in alpha-smooth muscle actin (primary cells), TGF-beta1, and collagen alpha1(I) mRNA (primary and immortalized cells). The profibrogenic response was dependent upon apoptotic body engulfment, because nocodazole, a microtubule-inhibiting agent, blocked both the engulfment and the increase of TGF-beta1 and collagen alpha1(I) mRNA. As described in primary rodent stellate cells, up-regulation of collagen alpha1(I) mRNA was inhibited by a PI-3K inhibitor (LY294002) and a p38 mitogen-activated protein kinase inhibitor (SB203580) in LX-1 cells. In conclusion, these data support a model in which engulfment of hepatocyte apoptotic bodies by stellate cells leads to a fibrogenic response by eliciting a kinase-signaling pathway.     

Experimental and clinical aspects of oxidative stress and redox regulation

Although excess amounts of oxidative stress damage proteins and nucleotides, small amounts of oxidative stress transduce intracellular signals for cellular activation, differentiation and proliferation. Reduction/oxidation(redox) regulation is defined as a biological response to maintain homeostasis against oxidative stress. Thioredoxin, a 12 kD small protein with a redox-active dithiol/disulfide in the conserved active site: -Cys-Gly-Pro-Cys-, is a key molecule for redox regulation as well as glutathione(GSH). Thioredoxin is induced by a variety of oxidative stresses and secreted from cells. Thioredoxin plays crucial roles as a redox-regulator of intracellular signal transduction and as a radical scavenger. Plasma levels of thioredoxin are good biomarkers for oxidative stress. Thioredoxin-transgenic mice are more resistant to cerebral infarction, infection or inflammation and survive longer than control mice. Administration of thioredoxin may have a good potential for anti-aging and anti-stress effects. Redox regulation mechanisms by thioredoxin and other thioredoxin family members will clarify the pathophysiology of oxidative stress-associated disorders.