Death Time Of Mice Research Articles

Expression of interleukin-17A in lung tissues of irradiated mice and the influence of dexamethasone.

Purpose. To investigate the expressions of IL-17A in different phases of radiation-induced lung injury and the effect of dexamethasone. Methods. The thorax of C57BL/6 mice was irradiated with 15 Gy rays. Mice from dexamethasone-treated group were injected intraperitoneally with dexamethasone (0.42 mg/kg/day) every day for the first month after irradiation. IL-17A in lung tissues was detected by immunohistochemistry. IL-17A, TGF-β1, and IL-6 in bronchoalveolar lavage fluid were detected by ELISA. Lung inflammation and collagen deposition were observed by H&E and Masson methods. The degree of alveolitis and fibrosis was judged according to scoring. Results. IL-17A expression was appreciable at 1 week, peaked at 4 weeks, and subsequently declined at 8 weeks after irradiation. IL-17A was reduced after dexamethasone application at all the observation periods. Dexamethasone also inhibited expressions of TGF-β, IL-6, and TNF-α in bronchoalveolar lavage fluid. Moreover, dexamethasone attenuated the severity of lung injury by reducing the infiltration of inflammatory cells and collagen deposition. Terms of survival and the time of death in mice of treatment group were postponed and survival rate was improved. Conclusions. IL-17A plays an important role in the process of radiation-induced lung injury. And dexamethasone may provide a protective role in lung injury induced by radiation.

Effects of injection speed of test samples on the mouse bioassay for paralytic shellfish poisoning toxins

The mouse bioassay has been used as the official method for paralytic shellfish poisoning toxins detection in Japan since 1980. However, differences in the results of this assay, when performed by different investigators, have been noted despite the use of the same sample. This study was performed to examine the effect of the injection speed, a hypothetical cause of such differences, on the death time of mice. Speed-controlled injection of the toxin (at 12, 6, 3, and 1.5 mL/min) into mice was performed using a syringe pump, and the death times of mice were measured. No statistically significant differences were found among the groups, even between fast injection (5 s) and very slow injection (40 s), indicating that the injection speed may not be the crucial factor for this assay.

Study of Antiseizure Effects of Matricaria recutita Extract in Mice

Matricaria recutita L. is a well-known medicinal plant that is suggested as being carminative, analgesic, and anticonvulsant in traditional medicine. In the present investigation the effect of hydro-methanolic percolated extract of this plant on seizure induced by picrotoxin was studied in male mice. This study was performed on animals pretreated with doses of 100, 200, and 300 mg/kg of extract or 40 mg/kg phenobarbital as the reference drug via intraperitoneal injection. After 20 min each animal received 12 mg/kg picrotoxin for induction of seizure. Latency of onset time of seizure, duration of seizure, death latency, and death rate were determined in experimental and control groups. The results showed that latency of the beginning time of seizure was increased in groups that were pretreated with different doses of extract. The most effective dose was 200 mg/kg (P < 0.05). In addition, this dose delayed the time of death in mice (P < 0.01). The extract had no effect on the death rate. The results indicate that the extract of M. recutita possesses suitable effects on seizure induced by picrotoxin, and more experiments are needed in this field.

The anti-snake venom activities of the methanolic extract of the bulb of Crinum jagus (Amaryllidaceae)

The anti-snake venom activities of the methanolic extract of the bulb of Crinum jagus plant (Amaryllidaceae) were investigated in vitro and in vivo against the venoms of three notable snake species: Echis ocellatus, Bitis arietans and Naja nigricollis. The extract was prepared by cold marceration in 50% methanol at 37 °C with intermittent shaking for 48 h. An yield of 12.8% w/w dry extract was obtained. Oral administration of C. jagus extract (1000 mg/kg) protected 50% of mice, while injection of a 30 min pre-incubated mixture of the same dose of extract and venom gave 100% protection against the lethal effects of E. ocellatus venom (10 mg/kg, i.m.). The intraperitoneal administration of the extract at 250 mg/kg, 30 min before the injection of E. ocellatus venom (10 mg/kg, i.m.), significantly ( p<0.05) prolonged the death time of poisoned mice. C. jagus extract (500 mg/kg, per os), gave 50% protection against B. arietans venom (9.5 mg/kg, i.m.) in mice while the pre-incubation of a mixture of the same dose of venom and extract (500 mg/kg), prior to injection (i.p.) of the mixture, gave only 33.3% protection. The pre-incubation of 500 mg/kg of C. jagus extract with N. nigricollis venom (6 mg/kg) prior to i.p. injection of the mixture protected 50% of the treated mice. There were generally no significant differences in the death times of mice that were given the same dose of the extract orally 30 min before injection of the venoms and those administered with the pre-incubated mixtures of venom and extract. The pre-incubation of the extract and E. ocellatus venom (5 mg/kg) for 30 min, before the i.m. injection of the mixture, significantly reduced infiltration of inflammatory cells to the site of injection 4 h post treatment. The concentrations of plasma creatine kinase in poisoned mice were significantly ( p<0.01 or p<0.05) reduced after the injection (i.p.) of C. jagus extract (1000 mg/kg) pre-incubated with E. ocellatus (5 mg/kg) or B. arietans (7 mg/kg) venom, respectively. The bulb extract of C. jagus blocked the haemorrhagic activity of a standard haemorrhagic dose (2.8 mg/ml) of E. ocellatus venom at various concentrations (1.7, 3.3 and 6.7 mg/ml). The methanolic bulb extract of C. jagus was therefore able to significantly protect mice from death, myonecrosis and haemorrhage induced by the lethal effects of venoms of notable snake species in Nigeria.

Dose-response Relationship for Life-shortening and Carcinogenesis in Mice Irradiated at Day 7 Postnatal Age with Dose Range below 1 Gy of Gamma Rays

This study was designed to elucidate the dose-response relationships for life-shortening and tumorigenic effect in the dose range below 1 Gy of gamma rays delivered during the infant period. Female B6C3F1 mice were irradiated with 0.10, 0.48 or 0.95 Gy at 7 days of age. All irradiated mice were allowed to live out their entire life span together with a simultaneously ongoing control group under a specific pathogen-free condition. Shortening of the mean life span was 1.58% in mice irradiated with 0.10 Gy, which was statistically significant . The coefficient of the linear dose-response relationship for life-shortening was 11.21% Gy(-1). The attributable death fraction for all causes of death in 0.10 Gy group reached 0.092. The excess relative risk for death rate from all causes was 0.102 in the group irradiated with 0.10 Gy. The coefficient of the linear dose-response relationship of the excess relative risk for death rate from all causes was 1.30 Gy(-1). The mean number of types of solid tumors at the time of death in mice irradiated with 0.10 Gy was distinctly larger than that in the control group. The excess relative risk for death rate from solid tumors was 0.45 in mice irradiated with 0.10 Gy. The coefficient of the linear dose-response relationship of excess relative risk for death rate from solid tumors was 4.52 Gy(-1). Increase in incidences of the pituitary, ovarian and adrenal tumors was observed in mice irradiated with 0.10 Gy. The results of the present study showed that infant mice are susceptible to solid tumor induction, especially of the endocrine organs.

Some Pharmacological PropertiesSolenostemon monostachyus

ABSTRACT The pharmacological effects of an ethanolic extract of Solenostemon monostachyus (Lamiaceae) were investigated in albino mice. Acute toxicity testing established the LD50 to be 537 mg/kg, orally (p.o.). Higher doses of extract produced a dose-dependent anticonvulsant activity against pentylenetetrazole induced seizure, but none was as potent as the reference anticonvulsant, phenobarbitone sodium. The extract delayed the onset of convulsions and the time of death in mice treated with an interparietal (i.p.) convulsive dose of pentylenetetrazole (100 mg/kg, i.p.) and strychnine (2 mg/kg, i.p.). The biological activity suggests the extract contains an anticonvulsant principle which depresses the central nervous system.

Relationship between domoic acid levels in the blue mussel (Mytilus edulis) and toxicity in mice

Monitoring of eastern blue mussels (Mytilus edulis), contaminated with domoic acid, involved mouse bioassays and quantitative analysis using HPLC. Mice undergo a typical scratching syndrome at sublethal as well as lethal doses of domoic acid. The onset of scratching behaviour and time of death in mice were inversely related to the dosage of domoic acid. An LD50 (i.p.) of 3.6 mg domoic acid/kg mouse was calculated. Toxic mussels held in tanks and flushed with uncontaminated sea water showed a decline in domoic acid concentration in mussel tissue with time. In addition, domoic acid concentrations in mussels from two infected rivers declined to negligible levels in 40-50 days under normal environmental conditions. The bulk of domoic acid and toxicity was located in the hepatopancreas which also contained large amounts of chlorophyll-A, an algae biomass indicator, relative to control mussels. These results support the conclusion that domoic acid was the primary causative factor in the shellfish poisonings from Prince Edward Island mussels in late 1987.

Toxicity of Puffer Roe Pickled in Rice-bran

Poisonous puffer roe has been processed for use as a food by pickling in rice-bran in Ishikawa Prefecture, However, the amount of poison in some of the products was higher than 10MU/g, the value established as the safety limit by the Ministry of Health and Welfare in 1954. Therefore, it was necessary to reduce the amount of poison in the pickled roe. In the course of studies to improve the manufacturing process, the extract-ability of puffer poison by three methods (with 0.1% acetic acid, methanol acidified to pH 4.0 with acetic acid, and water) and the effect of sodium chloride in tetrodotoxin solution on the death time of mice were examined. Moreover, the toxicity of spoiled puffer roe and its extract was tested, as Migita and Hashimoto had reported that toxicity of puffer roe extract was decreased when the roe had become spoiled. The following results were obtained:1) Among the three methods, water extraction was found to be the most efficient.2) When tetrodotoxin solution containing sodium chloride was injected intraperitone-ally into mice, their death time was increasingly prolonged as the salt concentration was increased.3) No clear relation between the toxicity and the spoilage of puffer roe (or its extract) was found in this study.

The Relationship Between the Dose of Taiwan Cobra (Naja Atra) and Taiwan Habu (Trimeresurus Mucrosquamatus) Venom and Time of Death in Mice

Summary The relationships between dosage of Naja atra venom and of Trimeresurus mucrosquamatus venom and the death-times of mice have been examined from experiments using intravenous injection. The observations were found to be well represented by the equation. The parameters of the dose-death time equation for both Naja atra and Trimeresurus mucrosquamatus were different from those found by Christensen and Finney (9) for Naja flava in mice. The weight of mice can be disregarded when weighing between 15 to 21 g for Naja atra and 15 to 20 g for Trimeresurus mucrosquamatus.

Standardization of Cobra (Naja Flava) Venom Using the Graded Response Method

Summary The relationship between dosage of Naja flava venom and death-time of mice has been examined from experiments using intravenous injection. The observations were found to be well represented by the equation . From this formula, a function of death-time can be constructed that has a linear regression on the logarithm of the dose over a wide range of doses, the function being . The logarithm of the time also is linearly related to the log dose over very nearly the same dose range. For both these response metameters, and over the same range of doses, the variance was found to be almost independent of the mean. Hence the potency of a preparation of venom may be assayed against a standard, using either f(T) or log T as a response metameter, in a parallel line assay of familiar type. The function f(T) has the advantage of giving a linear regression over a slightly greater range of doses, but redetermination of the numerical values of its parameters should precede its use in any other laboratory. At the South African Institute for Medical Research, assays of the (2 + 2) dose design have been found satisfactory; five trial assays reported in this paper used five animals at each of the four doses and gave limits of error of ±20% or less for a probability of 0.95.