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Biomedical subjects

A C Anderson

Publications and source records attributed to A C Anderson.

At least 73 records · Page 4Linked to original sources
PubMed1984

Measurement of modulation of mouse complement levels in vivo, utilizing a microtiter hemolytic assay.

The complement system, with its protein components, plays a fundamental role in host defense as the major immunological mechanism of innate immunity. Effects of immunotoxic agents on serum complement have not been studied due to the lack of an assay capable of measuring the in vivo effects of compounds in the mouse, the species of choice for immunotoxicological testing. A microtiter hemolytic assay was developed and utilized to measure modulation of serum complement in vivo in B6C3F1 mice. In order to validate this functional assay. Cobra Venom Factor (CVF) was used to produce decomplementation. CVF administered intravenously produced a dose-dependent suppression of complement activity when evaluated 24 hours after a single injection. Administration of 25 or more anticomplementary units (ACU/kg) completely abolished functional hemolytic activity. The duration of the effect was dose dependent with 100 ACU/kg suppressing the response for 48 hours. A decomplemented state could be maintained for up to 6 days, with a second injection. A third injection failed to prolong the decomplementation. Elevated complement levels were obtained following a single injection with Pyran Copolymer. Pyran, a macrophage activator, produce a dose dependent increase in serum complement levels 8 days after administration. The microtiter hemolytic complement assay represents a useful tool capable of evaluating the in vivo effects of agents on serum complement in the mouse.

Animals↗
PubMed1984

In vivo and in vitro effects of sodium azide on mouse complement.

A microtiter hemolytic assay was utilized to determine sodium azide (NaN3) modulation of B6C3F1 and C3H mouse serum complement levels in vivo and in vitro. Functional complement was expressed in CH50 units per milliliter. Experiments were performed to determine the in vitro effect of NaN3 on complement mediated lysis of IgM sensitized rabbit erythrocytes. Concentrations of 5, 10, 20, 30, 40, 60, and 80 mM NaN3 were added to microtiter wells containing Tris buffer, IgM sensitized rabbit erythrocytes, and serum complement from naive female C3H mice. Although NaCl and KCl controls had an inhibitory effect, NaN3 demonstrated a significant dose-dependent inhibition of complement-mediated lysis. In the three in vivo experiments, female B6C3F1 mice were exposed to NaN3 and physiological saline (vehicle control). Complement hemolytic ability was evaluated after a 1-day, single iv injection of 0.2, 2.0, and 20.0 mg/kg NaN3; at Days 1, 2, 3, 4, and 6 of a 6-day time course study after ip administration of 20 mg/kg NaN3; and at the end of an 11-day study involving daily injections of 10, 15, and 20 mg/kg NaN3 given ip. No significant changes in complement-mediated hemolysis were observed in the in vivo experiments. These studies indicate that NaN3 does not affect mouse complement levels in vivo. However, NaN3 suppresses in vitro complement hemolytic ability.

Animals↗
PubMed1984

Naphthalene toxicity in CD-1 mice: general toxicology and immunotoxicology.

Random bred CD-1 mice were used to evaluate the acute oral toxicity and subchronic toxicity of naphthalene administered in corn oil. The acute oral LD50 of naphthalene was 533 and 710 mg/kg in male and female mice, respectively. Subchronic toxicity was evaluated with 14- and 90-day daily oral gavage studies. Doses utilized in the 14-day study were 27, 53, and 267 mg/kg, with the latter representing one-half of the male LD50. Both males and females demonstrated a 5-10% mortality and depressed body weight at the high dose only. Males had decreased thymus weights, and females had decreased spleen and increased lung weights at the high dose only. Other organ weights were unaffected at any dosage level. Serum enzyme and electrolyte levels were not altered in a dose-related manner. To assess the potential immunotoxicity of naphthalene the following screen was utilized: humoral immune response, response to mitogens, delayed hypersensitivity response, popliteal lymph node response, bone marrow stem cell number, and DNA synthesis. No evidence of immunotoxicity was demonstrated. The 90-day study employed daily oral doses of 5.3, 53, and 133 mg/kg. There was no treatment-related mortality in either sex, nor was body weight affected. Organ weights were not affected in males, and females showed reduced spleen weights only at the high dose. Serum enzyme and electrolyte levels, as well as the immunotoxicity screen, indicated that naphthalene doses up to one-fourth the LD50 for 90 days failed to elicit consistent statistically significant and biologically relevant compound-related effects. A screen of the effects of the 90-day naphthalene treatment on various aspects of the hepatic drug metabolizing system indicated no alterations, with the exception of a specific dose-related inhibition of aryl hydrocarbon hydroxylase activity in both male and female mice.

Animals↗
PubMed1984

Uptake, distribution and elimination of monosodium methanearsonate following long term oral administration of the herbicide to sheep and goats.

The rate and extent of accumulation and washout of arsenic, during daily oral administration of the herbicide monosodium methanearsonate (MSMA) were evaluated in Iranian dairy sheep and goats. Subjects received a dose of 10 mg of MSMA as arsenic per kg of body weight daily for 28 consecutive days. The total arsenic concentration in blood and milk was measured during and after the period of MSMA administration while arsenic in urine and feces was measured for 10 days following administration of last dosage of MSMA. Arsenic was accumulated slowly during 28 days of MSMA administration and steady states were essentially complete in sheep after 20 days and in goats following 25 days of MSMA administration. Blood arsenic concentration decreased rapidly after termination of MSMA administration. In both test animals, the half-lives of washout were smaller than accumulation. The concentration of arsenic in the urine and feces of both species did not increase significantly over controls and animals were free of arsenic relatively shortly after administration stopped. These data indicate that arsenic from MSMA is mainly absorbed from gastrointestinal tract and is not significantly accumulated in the body. Arsenic is eliminated from body by way of urine and feces with urinary excretion being the most important route.

Animals↗
PubMed1984

Identification of nitroso compounds from biotransformation of 2,4-dinitrotoluene.

The intermediates of microbial transformation of 2,4-dinitrotoluene by a mixed bacterial culture derived from activated sludge were identified as 2-amino-4-nitrotoluene, 4-amino-2-nitrotoluene, 2-nitroso-4-nitrotoluene, and 4-nitroso-2-nitrotoluene. The biotransformation of 2,4-dinitrotoluene occurred only under anaerobic conditions with an exogenous carbon source. The two nitroso compounds were unstable and could be observed only at the early stage of 2,4-dinitrotoluene anaerobic biotransformation.

Journal Article↗
PubMed1983

Acceptance of hepatitis B vaccine among high-risk health care workers.

During a recent hepatitis B vaccination program among high-risk health care workers, the major sources of information about the vaccine were an in-service informational program, discussion with co-workers, and professional journals. Little or no information was obtained from the lay media or the product brochure. Two thirds of the personnel to whom the vaccine was offered accepted the vaccine. The major reason for accepting the vaccine was a perceived high-risk of contracting hepatitis B. In contrast, one third of the high-risk individuals offered the vaccine declined the opportunity. The major reason for not accepting the vaccine was concern with potential side effects. This information would have been helpful during the planning phase of the program.

Female↗
PubMed1983

Elimination of adverse effects of ethoxyquin (EQ) by methionine hydroxy analog (MHA). Protective effects of EQ and MHA for bitterweed poisoning in sheep.

Dietary ethoxyquin (EQ) and methionine hydroxy analog (MHA) protected 6-8-month-old wethers from toxic doses of bitterweed (Hymenoxys odorata DC.). The EQ-MHA group received sweet feed (corn, oats, dehydrated alfalfa pellets, cane molasses and minerals), 500 g/day/sheep, supplemented with EQ and MHA (0.5% and 1.0% of feed, respectively) for 9 days prior to the poisoning with bitterweed while the MHA group received the same feed without EQ and controls received the same amount of feed with no additives. Two of 6 MHA-treated and 3 of 7 controls died whereas all 7 EQ-MHA-treated sheep survived after receiving 5 doses of bitterweed (5 X 5.5 g/kg) in 6 days. Coadministration of MHA and EQ eliminated the adverse effect of EQ; dietary EQ lowered the serum albumin, calcium, and alkaline phosphatase content while protecting the animals from bitterweed poisoning. EQ is the most promising protective agent tested for bitterweed poisoning in sheep.

Animals↗
PubMed1982

Protective effects of antioxidants on bitterweed (Hymenoxys odorata DC) toxicity in sheep.

Antidotal effects of the 2 antioxidants butylated hydroxyanisole (BHA) and ethoxyquin (EQ) were evaluated in bitterweed (Hymenoxys odorata DC) toxicosis in sheep. Bitteerweed contains a toxic sesquiterpene lactone, hymenoxon, the toxicity of which is reduced by cysteine. Both BHA and EQ are known to induce hepatic glutathione production in rodents. Treatment of sheep with EQ (2.5 g/sheep/day for 9 days before poisoning) gave significant protection from toxic doses of bitterweed, but the protective effect of BHA was insignificant. Of 6 sheep given EQ in the feed, 5 survived 7 doses of bitterweed (4 g/kg/day or higher for 7 days), whereas 5 of 7 controls and 4 of 7 sheep given feed with added BHA died. The added EQ in the feed decreased the serum alkaline phosphatase activity and total protein, albumin, and calcium concentrations. Seemingly, EQ is the first protective agent with field application potential for bitterweed toxicity.

Animals↗
PubMed1982

Environmental factors and aggressive behavior.

This paper briefly reviews some of the research areas which indicate a correlation between environmental factors and initiation of aggressive behavior. Environmental factors including lunar influences, month of birth, climate and the effects of crowding and certain chemicals are discussed.

Aggression↗
PubMed1981

Biotransformation of the pesticide sodium arsenate.

Biotransformation is an important parameter in assessing the environmental impact and fate of pesticides since metabolites produced may be either more or less toxic than the parent compound. Sodium arsenate (+5 inorganic), the wood preservative and insecticide, may be converted to both inorganic (+3) and organic compounds (-3) by microorganisms in soil, sediment and water bodies. Biotransformation of sodium arsenate was studied in pure cultures of 5 bacterial species using a mineral salt and limited carbon source medium. Arsenate concentrations were 10 microgram/ml and 100 microgram/ml of arsenic respectively. The rate of biodegradation of the parent compound was described by a first order composite exponential equation of the form Ct = C1e-k1t+C2e-k2t. Rates of production of metabolites (arsenite, monomethylarsine, dimethylarsine and trimethylarsine) were described by a first order exponential equation of the form Ct = Co (1-e-kt).

Arsenates↗
PubMed1981

Effect of sodium arsenate on microbial growth in a chemostat.

Microbial transformation of sodium arsenate, the wood preservative and insecticide, is important in assessing the environmental impact of this pesticide. Recent studies using batch culture techniques have shown that arsenate is metabolized to more toxic end products. This study investigated the effect of the chemical on the microbial cells themselves using continuous flow cultures to examine the effect of arsenate on the growth and maintenance requirements of the microbes. Cell yield was lower and maintenance requirements higher at 100 micrograms/ml arsenate than at 10 micrograms/ml indicating a greater expenditure of energy by the cells to maintain homeostasis.

Arsenates↗
PubMed1980

Needlestick and puncture wounds: definition of the problem.

During 1979, all hospital personnel who were victims of needlestick or puncture wounds completed an incident questionnaire so that the epidemiology of these events could be determined. The attack rate varied from a high of 20 to a low of 0.8 incident/100 employee years worked (mean 7.5) for different employee groups. Personal carelessness accounted for 55% of the 81 incidents, whereas 35% of the involved personnel were innocent victims. Needles were responsible for 58% of the incidents. Screening for hepatitis B surface antigen (HBsAg) revealed no positive patient or employee associated with needlestick or puncture wounds. Only 2 of 45 employees were hepatitis B surface antibody (anti-HBs) positive. Hepatitis B immune globulin (HBIG) was recommended for 4 employees, immune serum globulin (ISG) for 13, and no globulin for 65. The estimated cost of this surveillance program and globulin therapy was $60 per incident. This data is being used as the basis for in-service training of high-risk personnel in order to decrease the number of incidents.

Cross Infection↗
PubMed1980

Accumulation of MSMA in the fruit of the blackberry (Rubus sp.).

The organic arsenical herbicide, MSMA, is used extensively for weed control along highway rights of way. Residues of the herbicide in edible crops growing near roadsides are of health concern since these products are accessible year round for harvesting by the unsuspecting public. This study examined the uptake and concentration of MSMA in the fruit of the blackberry during the various stages of maturation following the recommended application of 3.37 kg MSMA/hectare. MSMA-Aso accumulated with uptake being greatest in the earliest stages of fruit development. Arsenic levels consistently increased to concentrations of 25-30 microgram/g during one week following herbicide application to green fruit. Uptake during the later stages of development reached approximately 12.5 microgram/g in red and ripe fruit respectively. At all stages, uptake of herbicide in berries exceeded concentrations applied topically, indicating a major source of arsenic through transport from stems and leaves. Berries also absorbed herbicide following topical application to the fruit which is a significant source of arsenic following application in the later stages of development. The movement of herbicide to ripening fruit can be described by a three compartment model in which arsenic gains access from the surface of the berry and by translocation from stems and leaves. Parameter estimates for the model appear in the text.

Arsenic↗
PubMed1979

Screening of common bacteria capable of demethylation of methylmercuric chloride.

In summary, 21 bacteria were capable or degrading methylmercury chloride as measured by the disappearance of that species from the soil culture media. Disappearance of the methylated form was also accompanied by loss of total mercury in the culture media--probably as a result of reduction of the initial metabolite to volatile Hgo. The role of bacteria in the reduction step is not clear at this time although several authors (SUMMERS et al. 1972 and 1973; BISOGNI and LAWRENCE 1973 ) have suggested facilitated reduction rates in the presence of microorganisms.

Alkylmercury Compounds↗