LD50 Study Research Articles

Retention of Mutations in Colchicine-Induced Ornamental Succulent Echeveria 'Peerless'.

Mutation breeding has produced promising results, with exceptional attributes including pest/disease and environmental tolerance and desirable ornamental traits. Among the tools used in mutation breeding, chemical mutation is the most inexpensive way to develop novel plants. Succulents have gained popularity with high market demand because they require minimal watering and have plastic-like visuals. Ornamental succulents with rare leaf morphologies are costly. An LD50 study was conducted beforehand to determine the survival rates of colchicine-treated Echeveria 'Peerless'. Mutants in the first generation (MV1) were identified and analyzed. Determining whether mutagenic characteristics are carried to the subsequent generation (MV2) is a key component in breeding programs. Additional investigation was performed by producing MV2 plants through vegetative propagation to determine mutagenic retention. For MV2, mutants exhibited shortened leaves, increased leaf width and thickness, and fewer leaves, which significantly differed from the control, indicating compactness, wider leaf apex, and varying leaf color. To confirm the mutations, stomatal analysis was conducted, wherein there was a decrease in density and an increase in stomatal size. Likewise, chromosome counting and flow cytometry analysis confirmed the induction of polyploidization. Colchicine induction to develop new cultivars with novel phenotypic and cytogenetic characters is suitable for ornamental succulents.

Anti-Anaemic And Hepato–Renal Activities Of Ethanol Leaf Extract Of Alchornea Cordifolia In Phenyl Hydrazine Induced-Anaemic Wistar Rats

The effect of ethanol leaf extract of Alchornea cordifolia on some biochemical parameters in phenyl hydrazine-induced anaemic Wistar rats was studied. A total of thirty-six (36) Wistar rats weighing 95-200 g were selected for this study and randomly divided into six groups of six animals per group. Group A (normal control), group B (negative or anaemic) control, group C (standard), group D, E and F (treated groups). Animals in groups B, C, D, E and F were induced with anaemia via intraperitoneal (I.P.) injection of 10mg/kg body weight phenyl hydrazine (PHZ) for 3 days and group A received distilled water in place of the PHZ for the same duration. After the induction, group A and B rats received oral administration 0.9w/v normal saline solution while groups C, D, E and F received oral administration of enzoron (10mg/kg.bwt), 100, 200 and 400 mg/kg.bwt of extract respectively for 14 days. The percentage yield of the extract was determined to be 18%. Phytochemical screening revealed the presence of saponins, carbohydrates, protein, alkaloids, phytosterols, phynols, flavonoids and glycosides at varying concentrations.A dose of 5000mg/kg. bwt was found to be safe in the LD50 study of the extract. The oral administration of the extract showed a significantly (p<0.05) level of total protein (TP) ,packed cell volume (PCV), haemoglobin (Hb) and red blood cells (RBCs) of the animals in treated groups compared to those of the animals in anaemic groups.The aspartate transaminase (AST),alanine transaminase (ALT)and total bilirubin (TB)were significantly (p<0.05) lowered in the extract treated groups than in the anaemic non-treated groups. There was a no-significant decrease (p>0.05) in the serum urea, creatinine, Na+ ,K+ and ,Cl­- of animals in the extract treated groups when compared to both the normal and standard control . The histology of the spleen revealed the regeneration of damaged cells in extract treated groups unlike that of the anaemic non-treated groups which showed distorted architecture. The study suggests that treatment with Achornea cordifolia leaf extract in phenyl hydrazine induced anaemia enhances anti- anaemic and hepatoprotective effect possibly due to both its anti-inflammatory and antioxidant properties.

English

Snail slime is used widely in African traditional medicine, specifically in Nsukka Enugu, Nigeria, for wound management; however, this claim lacks scientific validation. Herein, we investigated the gastroprotective effect of aqueous Achatina achatina L. (snail) slime extract (ASSE) on indomethacin- and ethanol-induced ulceration in Wistar albino rat models. Biochemical analysis of ASSE showed appreciable levels of manganese, iron, zinc, copper, molybdenum, selenium, Vitamin C, B1, B2, and B3 and a basic pH. The experimental design consists of two Phases (five groups of five rats each). In both Phases, group I (positive control) received 3ml of distilled water, while groups II-V received 20 mg/kg body weight omeprazole (standard drug), 50, 100, and 200 mg/kg bw ASSE, respectively, via oral intubation. The various treatments lasted for 21-days. Following 24-hours fasting with access to only water (which spanned between the 22nd -23rd day), ulceration was induced separately on the experimental animals in Phase I with a single oral dose of indomethacin (30 mg/kg bw) and in Phase II with a single oral dose of acidified ethanol (1.5 ml/ kg bw), via the gastric gavage. The LD50 study showed safety up to 5000 mg/kg bw ASSE. After induction, a significant (P<0.05) increase in the number of ulcers and mean ulcer index were recorded in group 1 of both Phases; however, rats administered various concentrations of ASSE showed significant (P<0.05) amelioration of the ulceration in both Phases, and these were on par with the standard control. These results suggest that aqueous snail slime extract possesses gastroprotective potential

Antidiabetic Activity of Ethanolic Extract of Seed Kernel of Sapindus emarginatus in Rats

Hyperglycemia is indeed a dyslipidemia across a Globe. An International Diabetes Federation (IDF) has Predicted a certain 366 million more people have diabetes in 2011 and it has been raised up to 552 million by 2050. It approximated a certain 40 million people of hyperglycemia through India in 2007 and yet this may predicted to grow almost to 70 million affected by 2025. LD50 study of the ethanolic extract of S. emarginatus seed kernel (EESESK) has been done throughout Albino rats up to a daily dosage constrain of 2000 mg/kg orally (according to OECD guidelines No.425 of CPCSEA) 1/5th, 1/10th dosage as from maximum dose examined for LD50 study results were again for experimental test research to examine a impact of S. emarginatus for a anti diabetes action. Insulin inefficiency was found in two selected model for my study. Alloxan hydrate at such a mg dosage of 150 mg/kg i.p after 48 hrs, the EESESK seed kernel it at a dosage of 200 mg/kg but also 400 mg/kg p.o have been administered. Dexamethasone 10 mg/kg, i.p, once daily. And at the inter of 30 mins EESESK 200 mg/kg and 400 mg/kg p.o had been conducted in rats for a period of 11 and 21 days respectively. At the end of the experimental, serum biomarkers such as glycogen, high cholesterol, triglycerides, LDL, HDL, and VLDL were analyzed by using semi-auto analyzer. In both models EESESK at a dose of 400 mg/kg exhibited substantial impact. Alloxan hydrate increased serum biochemical markers like glucose, high cholesterol, triglyceides, LDL, VLDL levels but decreased HDL levels. Dexamethasone caused an increase in serum glucose, High cholesterol and reduces High density lipopretein-cholesterol levels. The present study indicates that S.emarginatus seed kernel useful for the management of diabetes mellitus. S.emarginatus pollen seed found important reducing of glycogen TC, TG, LDL, VLDL levels and increased level of High Density Lipoprotein through diabetic concept mice. A enhanced high density lipoprotein is also Cardioprotective activity. Therefore S.emarginatus seed kernel must have future role to forestall forming of atherosclerosis but also cardiovascular disease.
 Keywords: Antidiabetic activity, Ethanolic extract, Seed kernel and Rats

Identification of two death camas chemotypes within a population and evaluation of toxicity

Foothill death camas (Zigadenus paniculatus) is a native, cool-season, bulbous perennial forb found throughout the western U.S. The toxins in death camas are steroidal alkaloids. Zygacine is often the most abundant alkaloid in death camas and is believed to be the primary toxic component. A population of death camas with plants consisting of two different chemical profiles (chemotypes) growing within the same location were identified. The objective of this study was to determine the percentage of a death camas population represented by each of the different chemotypes and to determine if there was a difference in toxicity between the two chemotypes. One third of the population sampled consisted of chemotype 1, while two-thirds of the population consisted of chemotype 2. The zygacine concentration of chemotype 1 was three times higher than chemotype 2. Chemotype 2 contained higher concentrations of several other steroidal alkaloids than chemotype 1. We hypothesized that chemotype 1, which consisted of higher concentrations of zygacine, would be more toxic than chemotype 2. The acute toxicity of each chemotype was determined in mice and sheep. In the mouse LD50 study, the acute toxicity of the chemotype 1 alkaloids (2.3 mg/kg BW) was different than the chemotype 2 alkaloids (3.2 mg/kg BW). However, in the sheep study there were no differences in the adverse effects between chemotypes. Based upon the results of this study, caution should be taken when livestock are grazing death camas, as both chemotypes of death camas appear to pose a similar risk to grazing livestock.

Evaluation of the acute toxicity of Thymus linearis ethanol extract and its effect on the hemato-biochemical and behavioural response of the Golden mahseer, Tor putitora (Hamilton, 1923).

The present investigation was conducted to estimate the acute toxicity of Thymus linearis plant extract, its effect on hemato-biochemical parameters and behavioural response in the golden mahseer (Tor putitora). The phytochemical composition present in T. linearis plant extrat were Alkaloids, Flavonoids, Phenols and Tannin. The fishes were subjected to eight different concentrations of T. linearis leaves extract (8.25, 8.50, 8.75, 9.00, 9.25, 9.50 and 9.75 mg/kg) and the control group without plant extract for 96-h LD50 study. The mortality was recorded every 24 h post-treatment. Minimum mortality was recorded in the 8.25 mg/kg, whereas 100% mortality was recorded in the 9.75 mg/kg T. linearis extract after 96-h periods. The LD50 was estimated by probit analysis, and the value of T. linearis at 96 h was found to be 8.71 mg/kg for golden mahseer. A non-lethal dose of 1/10th of 96-h LD50 value (0.87 mg/kg) was taken for the sublethal study. After 96 h, the red blood cell (RBC), white blood cell (WBC), haemoglobin (Hb), packed cell volume (PCV) and blood glucose were measured. RBC (×106/mm3), Hb (%) and PCV (%) significantly decreased at 8.25, 8.50, 8.75, 9.00 mg/kg, but WBC and blood glucose significantly increase at 8.25, 8.50, 8.75, 9.00 mg/kg of T. linearis plant extract. The observations on behaviour response of golden mahseer were also recorded. In the present study, the acute toxicity of wild ajwain was more significant than short-term toxicity. The mortality rate was very high during the study period of T. linearis exposure.

Methamphetamine-Induced Open Field Behavior and LD50 in Periplaneta americana Cockroaches (Blattodea: Blattidae).

Invertebrate animal studies of methamphetamine (METH) could allow for high throughput, inexpensive, and high-animal number pharmacology and toxicology studies. We hypothesized that in Periplaneta americana cockroaches, METH would increase locomotion compared to saline and produce lethality. Lethal dose, 50% (LD50) was determined with 0-1,780 µg/g (mg/kg) METH (n = 15-16/group) using logit analysis. Locomotor activity after METH (0-560 mg/kg, intra-abdominal, n = 8 per group) administration and spontaneous locomotor activity in surviving cockroaches in an open field 24 h after LD50 study doses was measured with Noldus Ethovision. The LD50 of METH was 823.1 mg/kg (more than 10-fold greater than the value in rats). There were significant decreases in spontaneous locomotor activity in surviving cockroaches after administration of 650 and 750 mg/kg METH (P < 0.05). While 100 mg/kg METH did not significantly increase METH locomotor activity relative to saline, 300 mg/kg METH significantly increased locomotor activity compared to saline (P < 0.05), and 560 mg/kg METH resulted in most of the cockroaches slowly moving around the open field in the supine position for most of the trial. In conclusion, METH produces pharmacological and toxicological effects in P. americana. The high availability, low cost, and relative ease of use of these animals makes them a potential, very accessible option for studying METH use disorder.

Methamphetamine-induced Locomotor Activity and LD50 in Cockroaches

Invertebrate animal studies of methamphetamine (METH) could allow for inexpensive, high throughput exploration of many variables that could be used to direct the design of future vertebrate pharmacology and toxicology studies. We hypothesized that METH would both increase locomotion compared to saline and produce dose-dependent lethality in male Periplaneta americana cockroaches. LD50 was determined with 0-1780 mg/kg METH (n=15-16/group) using probit analysis. After the LD50 study, automated behavioral analysis software interfaced with overhead cameras was used to measure spontaneous locomotor activity in surviving cockroaches in an open field. In separate experiments, METH-induced locomotor activity was measured in an open field (0-560 mg/kg, n=8/group). A 1-way ANOVA with Holm-Sidak’s multiple comparisons test was used for statistical comparisons in both locomotor studies. The LD50 of METH was found to be 738 ± 151 mg/kg (almost 10-fold greater than the value in rats). There were significant decreases in spontaneous locomotor activity in surviving cockroaches after administration of 650 and 750 mg/kg METH (P &lt; .05). While 100 mg/kg METH did not significantly increase METH locomotor activity relative to saline, the 300 mg/kg dose significantly increased this effect (P &lt; .05), and the 560 mg/kg dose resulted in the cockroaches remaining in the supine position for the majority of the trial. In conclusion, METH has pharmacological and toxicological effects in cockroaches, but they are less potent than in rodent models. Funding: Marshall University School of Pharmacy Faculty Research Seed Grant.

The LD50 Study of Chemical Derived from The Ash Of The De-Seeded Fruit Head Of Oil Palm In Mice

The LD50 Study of Chemical Derived from The Ash Of The De-Seeded Fruit Head Of Oil Palm In Mice

Anti-inflammatory Activity of Tuber Extracts of Solanum tuberosum in Male Albino Rats

The objective of present investigation was to evaluate the anti-inflammatory activity of tuber extracts of Solanum tuberosum in rats. Anti-inflammatory models like Carrageenan, Histamine and Formalin induced paw edema were used for evaluating anti-inflammatory activity. Ibuprofen was used as standard drug. The alcoholic extract as well as aqueous extract of tubers of S. tuberosum subjected to LD50 study shows that none of them produced behavioral abnormalities or mortality of the experimental animal (rat) even at the dose level of 2000 mg/kg body weight. In anti-inflammatory models, selected doses of both the extracts AETST and AQETST like low (100 mg/kg), medium (200 mg/kg) and high (400 mg/kg) significantly reduced the inflammation. The present study revealed that both the AETST and AQETST possessed anti-inflammatory activity.

In vitro and in vivo efficacy of partially purified herbal extracts against bacterial fish pathogens

The effect of partially purified extracts of sea grass (Cymodocea serrulata), turmeric (Curcuma longa), Spirulina (Spirulina platensis), and beet root (Beta vulgaris) on the antimicrobial, antioxidant, and hemato-biochemical changes in ornamental dotty back, Pseudochromis dilectus against isolated fish bacterial pathogens (Proteus mirabilis, Bacillus pumilus, and Staphylococcus sciuri) under in vitro and in vivo conditions is reported. Among the extracts turmeric extract exhibited significant antibacterial activity. The extract possesses the highest antioxidant property and phenol content; the GC–MS analysis revealed the highest presence of Ar-turmerone (42.85%) and Curlone (18.80%). The potential fractions possess reducing power and free radical scavenging activity. The mortality against P. mirabilis at doses of 2.5×108 and 2.5×108CFU was 100% whereas against S. sciuri (2.5×107 and 2.5×108) it was 70 and 80%. The highest bacterial load was observed in kidney (3.1×107CFU/g) and liver (2.6×108CFU/g) against P. mirabilis. The LD50 study suggested that all the fish die at doses of 2.5×107 (CFU/fish) and 2.5×108 (CFU/fish) after 15days of challenge with P. mirabilis. Among the purified sub fractions, the sub-fraction II (F-II) at 5 and 10mg/ml resulted in elevated levels of WBC and RBC, lymphocytes, and neutrophils; further the percentage of monocytes and granulocytes, total protein, total lipid, and glucose also increased significantly. At 1mg/ml the relative percent survival (RPS) was 100% in sub-fraction II (F-I) group as in control. With 5mg/ml in F-I and 1mg/ml in F-II group the RPS was 94%; however, in 10mg/ml of F-I and 5mg/ml of F-II groups the RPS declined to 89%. The lowest mortality of RPS (79%) was observed in 10mg/ml in F-II group. The present results suggest that the partially purified turmeric extract elevated antimicrobial and antioxidant activities by improving the hemato-biochemical profiles and survival rate in P. dilectus against P. mirabilis. Statement of relevanceThe success of any fish culture depends on the health status of cultivated species. Fish diseases are one of major threats in aquaculture industry inflicting heavy mortality in the world. To prevent and control of the diseases traditionally was used several antibiotics or chemicals during the last few decades. However, these methods have been criticized for their negative impacts such as accumulation of drugs in tissues, development of drug resistance, and immunosuppression. Several herbal and their active principles possess better antioxidant activity, phenols content, reducing power, and free radical scavenging activity. Therefore in the present study was isolated new fish pathogen from the infected fish and to investigated antioxidant activity and their pathogenicity and hematological changes in dotty back, P. dilectus against P. mirabilis. This work is novel in aquaculture to design or prepare cost effective drug or feed for fishes.

Decorporation of Iron Metal Using Dialdehyde Cellulose-Deferoxamine Microcarrier

Deferoxamine iron chelator has a limited therapeutic index due to rapid clearance from blood and possesses dose-limiting toxicity. Therefore, an intravenous deferoxamine delivery system based on dialdehyde cellulose (DAC) polymer was developed and its efficacy and toxicity were tested in iron-overloaded animals. The amino groups of deferoxamine were conjugated to free aldehyde moieties of dialdehyde cellulose via Schiff base reaction to form dialdehyde cellulose-deferoxamine (DAC-DFO) conjugate and characterized by Fourier transform infrared spectrophotometer, scanning electron microscope, and X-ray diffraction. The toxicity of prepared formulation was analyzed by XTT cell viability assay and LD50 study in mice. The change in serum iron levels, after intravenous administration of formulation, was observed in iron-overloaded rats. The DAC-DFO conjugate was tagged with Tc-99m to study the blood kinetics and observe change in blood circulation time. DAC-DFO conjugate was dispersible in water at concentration ∼75mg/ml. In vitro cytotoxicity assay and LD50 study in mice indicated significantly enhanced safety of covalently bound deferoxamine (at >1000mg/kg body weight compared to free drug at ∼270mg/kg dose). A preliminary scintigraphy imaging and blood clearance study, with technetium-99m, indicated prolonged circulation of conjugated DFO in rabbit blood. A single dose of formulation injected into iron overloaded animals was found to maintain the normal serum iron levels until 10days. The polymeric conjugate was effective in maintaining normal serum iron levels until 10days at a dose of 100mg/kg body weight.

Wound Healing Effect of Methanol Leaf Extract of Napoleona Vogelii Family (Lecythidaceae)

Background: Wounds which results from an injury or trauma to any tissue of the body, has been claimed to be managed by traditional healers, with over fifty plants reported to have shown wound healing effect or properties. A good example is the Napoleona Vagelii commonly called Mkpodu in Igbo language. Extract from this plant is sometimes prepared as polyherbal medicine. The use of plant extract in the external management of wound is becoming widely acceptable because there is a growing interest in the clinical practice of wound management with the use of chemical component impregnated dressing. Objectives: To confirm the wound healing property of Napoleona Vagelii plant as claimed by folkloric medicine. Methodology: A total number of 20 adult albino rats and 12 mice were used for the wound healing study and for the LD50 study respectively. They were provided with adequate food, drinking water and comfortable cage and housed at the Madonna University animal house. The rats were grouped into five groups of four rats in each group. The hairs of the trunk part of the rats were shaved with a razor and 1.5cm wound was inflicted on each rat using a surgical blade. Petroleum jelly (Vaseline) was applied topically on the wounds of Group A rats, 2mg of Neobacin was applied topically on the wounds of group B rats, while 50mg, 100mg and 150mg of Napoleona Vagelii leaf extracts were also applied topically on the wounds of group C,D, and E rats respectively. The various applications for each group of rats were done on alternate days and the diameter of the wounds measured to assess healing responses. Results: It showed that the methanol extract of Napoleona Vogelii leaf has a wound healing activity, which was however not dose dependent. It showed a very significant wound healing (P < 0.5) Conclusion: Improvement in wound healing by the application of extract of Napoleona Vogelii leaf has been demonstrated by this research. Further works should be carried out by researchers to formulate a medicament for human use from it.

Escape from the pond: stress and developmental responses to ranavirus infection in wood frog tadpoles

Summary 1. Animal populations exhibit considerable variation in their susceptibility to infection by emerging diseases, yet it is poorly understood how environmental and intrinsic factors contribute to these patterns. Considering that intrinsic factors (e.g. life history stage, nutritional state) can impact immune function, knowledge of the physiological mechanisms that mediate susceptibility to infection may improve our understanding of the emergence of disease in natural populations. 2. Ranavirus outbreaks have been associated with die‐offs of amphibians worldwide. While the ecological factors associated with epidemics have been widely studied, little is known about how physiological factors mediate amphibian responses to ranavirus infection. 3. The neuroendocrine hypothalamus‐pituitary‐interrenal axis (HPI) is a physiological system central to coordinating energy balance and development. It is known to both stimulate and inhibit immune function in vertebrates in different contexts. We hypothesized that the HPI axis would also mediate responses to ranavirus infection. We used wood frog (Rana sylvatica) larvae and ranavirus isolated from recent die‐offs of local wood frog populations to examine the physiological responses to infection. 4. In addition to increasing odds of death with increasing doses of virus in an LD50 study, we saw a 1·7‐fold increase in the odds of death with each increase in Gosner stage at the time of infection. 5. We then examined the HPI stress response of prometamorphic tadpoles exposed to a lethal dose of ranavirus. Infected tadpoles exhibited significantly elevated corticosterone levels, more rapid developmental changes, and a greater decrease in body weight relative to controls over 6 days after exposure. 6. Although elevated corticosterone mobilizes resources and enhances immunity, its acceleration of metamorphosis may be maladaptive in response to ranavirus infection, because it can draw energy away from expensive immune responses. These findings provide insight into how the balance of energy between development and immune function may contribute to patterns of ranavirus infection in pre‐metamorphic amphibians.

Comparison of fluid types for resuscitation after acute blood loss in mallard ducks (Anas platyrhynchos)

The purpose of this study was to determine the LD(50) for acute blood loss in mallard ducks (Anas platyrhynchos), compare the mortality rate among 3 fluid resuscitation groups, and determine the time required for a regenerative RBC response. Prospective study. Medical College of Wisconsin Research facility. Eighteen mallard ducks were included for the LD(50) study and 28 for the fluid resuscitation study. Phlebotomy was performed during both the LD(50) and fluid resuscitation studies. Ducks in the fluid resuscitation study received a 5 mL/kg intravenous bolus of crystalloids, hetastarch (HES), or a hemoglobin-based oxygen-carrying solution (HBOCS). The LD(50) for acute blood loss was 60% of total blood volume. This blood volume was removed in the fluid resuscitation study to create a model of acute blood loss. Following fluid administration, 6 birds in the crystalloid group (66%), 4 birds in the HES group (40%), and 2 birds in the HBOCS group (20%) died. No statistical difference in mortality rate was seen among the 3 fluid resuscitation groups. Relative polychromasia evaluated post-phlebotomy demonstrated regeneration starting at 24 hours and continuing through 48 hours. The LD(50) for acute blood loss in mallard ducks was 60% of their total blood volume. Although no statistical difference in mortality rate was appreciated among the 3 fluid resuscitation groups, a trend of decreased mortality rate was observed in the HBOCS group. An early regenerative response was apparent following acute blood loss.

Toxicopathologic Effects of Artemisinin in Broiler Chickens Following a Single Oral Dose: An LD50 Study

The present study aimed to find LD of artemisinin and to characterize the single dose toxicity of 50 the drug following oral exposure. 49 day-old Ross broilers divided into 7 groups; one control, one drug vehicle and five treatment groups. The treatment groups received artemisinin alcoholic solution at doses of 10, 50, 250, 1250 and 2500 mg/kg on day 30 by a crop tube. The control and drug vehicle groups received normal saline and ethyl alcohol, respectively. In the period of study just in 1250 and 2500 mg/kg groups there were a few transient neurological signs like depression and unconsciousness. These signs were also observed in drug vehicle group. None of the birds died, so they were euthanised on day 40. In microscopic examination, only in treatment groups a slight degeneration in liver and kidney as intracytoplas mic eosinophilic inclusions, hepatocellular swelling and bile retention in liver were evident. In brain central chromatolysis, scattered neuronal necrosis, spongy change and focal axonal swelling were observed. It is concluded that artemisinin has a good margin of safety in poultry but in very high doses it may cause some adverse effects.

Toxicity of oral exposure to 2,4,6‐trinitrotoluene in the western fence lizard (Sceloporus occidentalis)

Contamination of the soil with the explosive 2,4,6-trinitrotoluene (TNT) has been found at military sites, many of which are habitats used by reptiles. To provide data useful in assessing ecological risk for reptilian species, acute, subacute, and subchronic oral toxicity studies were conducted with the western fence lizard (Sceloporus occidentalis). Oral median lethal dose (LD50) values for TNT in corn oil were 1,038 and 1,579 mg/kg of body weight for male and female lizards, respectively. Overt signs of toxicity included chromaturia, abdominal enlargement, and tremors. A 14-d subacute study followed in which male lizards were orally dosed with TNT (corn oil) at 0, 33, 66, 132, 263, 525, and 1,050 mg/kg of body weight each day. Clinical signs of toxicity, while similar to the LD50 study, were more subtle and noted in lizards receiving TNT amounts of at least 66 mg/kg/d. Chromaturia was an early consistent sign, often preceding the onset of adverse effects. Male lizards in the 60-d subchronic study were dosed at 0, 3, 15, 25, 35, and 45 mg/kg/d with nearly complete survival (>90%) for lizards in all treatments. Changes in food consumption and body weight were observed at 35 and 45 mg/kg/d. Alterations in hematological end points; blood chemistries (albumin, total protein, alkaline phosphatase, calcium); kidney, spleen, and liver weights; and adverse histopathology were observed in lizards exposed at 25 to 45 mg/kg/d. Testosterone concentration, sperm count, and motility were variable between treatments. Although not significant, incidences of hypospermia and testicular atrophy were observed in some individuals. Together, these data suggest a lowest-observed-adverse effect level of 25 mg/kg/d and a no-observed-adverse effect level of 15 mg/kg/d in S. occidentalis.

Effects of Gasoline on Blood Cells and Liver Functions of Albino Rats (Rattus rattus)

The acute toxicological effects of gasoline on blood cells, and liver functions of albino rats were investigated. The rats were intraperitoneally injected with gasoline at different dose levels and were observed within 24 hours for signs and symptoms of toxicity. From the pilot study, 35.0g/kg was obtained as the minimum dose of gasoline that caused 100% death (LD100). Furthermore, LD50 study gave 12.30g/kg as the dose of gasoline that caused 50% death in rats (median lethal dose). The symptoms observed included occurrence of pallor, sedation, respiratory distress, coma and death and they were dose-dependent. Death rate increased with increase in the concentration of gasoline. The results of the hematological parameters obtained showed decrease in the mean + SEM values with increase in doses of gasoline injection. The biochemical parameters obtained showed an increase in the ALT and AST levels from 0.00 to 35.0g/kg and a corresponding increase in the ALP level from 0.00 to 35.0g/kg, indicating a case of hepatotoxicity. Direct and total bilirubin were also increased with increase in the doses of gasoline. The results, of this study showed that exposure to gasoline is potentially toxic and the degree of toxicity may be influenced by the dose or concentration to which persons are exposed. Keywords: Albino Rat, Gasoline, Histopathology Journal of Medical Laboratory Science Vol. 13 (2) 2004: pp. 24-28

Acute oral toxicity.

The purposes of acute toxicity testing are to obtain information on the biologic activity of a chemical and gain insight into its mechanism of action. The information on acute systemic toxicity generated by the test is used in hazard identification and risk management in the context of production, handling, and use of chemicals. The LD50 value, defined as the statistically derived dose that, when administered in an acute toxicity test, is expected to cause death in 50% of the treated animals in a given period, is currently the basis for toxicologic classification of chemicals. For a classical LD50 study, laboratory mice and rats are the species typically selected. Often both sexes must be used for regulatory purposes. When oral administration is combined with parenteral, information on the bioavailability of the tested compound is obtained. The result of the extensive discussions on the significance of the LD50 value and the concomitant development of alternative procedures is that authorities today do not usually demand classical LD50 tests involving a large number of animals. The limit test, the fixed-dose procedure, the toxic class method, and the up-and-down methods all represent simplified alternatives using only a few animals. Efforts have also been made to develop in vitro systems; e.g., it has been suggested that acute systemic toxicity can be broken down into a number of biokinetic, cellular, and molecular elements, each of which can be identified and quantified in appropriate models. The various elements may then be used in different combinations to model large numbers of toxic events to predict hazard and classify compounds.

Vibrio anguillarum serogroup O3 and V. anguillarum-like serogroup O3 cross-reactive species—comparison and characterization

Forty-five Vibrio anguillarum-like isolates reacting with V. anguillarum serogroup O3 antiserum were examined in 30 characters to clarify their phenotypical properties, while their genotype was examined by ribotyping. The strains were isolated from diseased and dead fish or from environmental sources such as water, sediment, plankton, and faeces and gills of healthy fish. Phenotypically, the similarity of all the strains was more than 90%. However, significant differences between the fish-associated and environmental strains were detected. Biochemically, deviations were found in the Voges-Proskauer test and lysine decarboxylase reaction. Clustering analysis of the ribotypes showed two distinct clusters with a similarity of only 32%. Two strains representing each of these groups were used in a LD50 study, which showed some difference also in the pathogenicity between environmental and fish strains. It is suggested that the environmental strains belong to another species than V. anguillarum, but serologically cross-reacting with the V. anguillarum serogroup O3. The ribotyping as well as biochemical results indicated that the environmental strains possibly belong to Vibrio aestuarianus. The bona fide V. anguillarum serogroup O3 strains proved to be very homogeneous both phenotypically and genotypically, and the similarity of ribotypes was more than 96%. The V. anguillarum-like, serogroup O3-reactive strains from the environment were more heterogeneous in their biochemical behaviour, and showed an approximately 70% similarity in ribotypes.