Effect of manganese on the concentration of amino acids in different regions of the rat brain

Abstract

The present study was designed to determine if chronic exposure of weanlings and adult rats to Mn produces significant alterations in amino acid concentrations in different regions of the rat brain. Weanling (30 day old) and adult (90 day old) male rats were exposed to 10 and 20 mg Mn/kg body weight per day, by gavage, for 30 days. Forty‐ eight hours after the last dose, animals were sacrificed by decapitation and brains were dissected into different regions to determine the concentration of amino acids by HPLC/EC. A dose dependent decrease in body weight gain was found in the adult, but not in the weanling rats. Significant increases occurred in concentrations of aspartate, glutamate, glutamine, taurine and y‐aminobutyric acid (GABA) in the cerebellum of the adult rats dosed with 20 mg/kg per day, Mn. A significant decrease in the concentration of glutamine was observed in caudate nucleus and hippocampus of weanling rats dosed with 10 mg/kg, Mn. These data suggest that chronic Mn exposure can produce a decrease in body weight gain in adult rats and alterations in amino acids in different regions of weanling and adult rat brains.     

Contaminant Emissions from the Combustion of Fuels

In the past several years the use of cattle feeding lots for preparing cattle for market has developed into a large industry. These installations extend over much of the United States. Our lot, just outside of Memphis, Tennessee, is at present the only one in the area, but we feel that there will be others soon.

The control of odor in the cattle feeder industry is necessary if the operator does not wish to become the target of a nuisance or injunction suit. In one recent trip extending to Texas, then to California and back, numerous lots were inspected and this paper will present various types of odor control measures which were observed. The problem is one which can be controlled, but it is primarily dependent upon the willingness on the part of management to make the effort.

As a by-product of the cattle feeder lot, large quantities of manure are obtained and unless measures are taken to properly store this material, considerable odor can result. We believe that the use of dehydration in connection with the feeder lot will become more and more necessary, and it is our experience that this type of operation requires: 1. Good design of the dehydrating unit, 2. Careful control of the product flow, 3. An understanding of the proper method for storing the manure prior to its dehydration, and 4. Use of odor control methods to keep down those odors which would constitute nuisance to those living nearby. Various methods of odor control will be discussed.     

The Interstate Air Pollution Surveillance Program Effects Network

A program has been designed to meet a nationwide intelligence-gathering responsibility to obtain general and relative information on current and potential air pollution in areas where interstate transport of pollution may reasonably be expected to exist. This paper describes the field devices utilized in the program. By means of these static “effects packages,” data will be accumulated on: dustfall, particulate impingement, sulfation, corrosion, and tarnishing of metals, and deterioration of textiles, dyes, and rubber. Data accumulated during the “pilot phase” of the program will be discussed.     

Air Pollution Impacts to Some Important Species of Pine

In the past, many species of pine have been severely damaged by acute forms of air pollution associated with ore smelting. More recently, damage to ponderosa pine in the state of Washington has been associated with atmospheric fluoride, and this species in particular has also suffered smog damage in southern California. In the East, white pine has been declining in the vicinity of certain soft-coal-burning power plants, and in one case downwind from an oil-burning power plant: also, throughout the East, an atmospheric oxidant of unknown source has caused a type of needle blight on white pine. Trash burners and city dump combustion have led to the hilling of certain pine species, leaving other intermixed pine species unharmed. Localized damage to white pine from automobile exhaust has been observed. Differences in the susceptibility of neighboring trees of the same species to a given air pollutant have been observed repeatedly.     

An Appraisal of Epidemiologic Data Concerning the Effect of Oxidants,Nitrogen Dioxide and Hydrocarbons upon Human Populations

A procedure is developed for determining costs to reduce air pollution emissions in a metropolitan area. Methods are. sufficiently general to be applicable in any region and sufficiently comprehensive to include analysis of all major sources, future trends, control limitations, and other factors of importance in a dynamic community. The analytical procedure examines relationships among emission inventories, regional growth, control trends, alternate control schemes, control costs, and optimum cost-effectiveness.

The cost analysis procedure is tested by application to the Delaware Valley. Costs are determined for reducing emissions to various levels between the years 1960 and 2000. Emissions from private automobiles are projected to decrease below the 1960 emission rate by 1980, at a cost of 150 million dollars per year. Stationary source emissions of sulfur dioxide and particulates can be reduced to 1960 levels by 1980 for 37 million dollars per year if "least cost" procedures are used (selective abatement). Uniform conversion to 0.5% sulfur fuel oil (equiproportional abatement) can effect a similar reduction in emissions for about 94 million dollars per year in 1980. Other cost analysis comparisons are made and projections to the year 2000 are included.     

United States Seen 2.54 Centimeter-ing Its Way to Metric System

On May 3, 1971, the Engineers Joint Council sponsored a panel on metrication at its offices in New York City. Bryce MacDonald of EJC was chairman; he had been instructed to invite representatives of various societies. Its purpose was to “present to the Board of EJC a summation of the situation regarding plans for conversion to the metric system.” The EJC Board will later come to a decision whether it will assume a more active role.

George Arnold of Southern Illinois University, Edwardsville, was named to represent the Air Pollution Control Association on the panel because of his long-standing membership in the Metric Association and his efforts toward exclusive use of international units for pollution measurement.

Twenty-two societies were represented. These included ASME, ASTM, SNAME, ASQC, ASHRAE, ISA, ASEE, ASCE, and ESNE. Among those present was Gregory Schultz of the Material Management Society, who is prominent with the American National Standards Institute and the International Standards Organization. Of the societies present, only six have a firm policy in favor of the metric system. The others are cautiously in favor, or using dual units, or waiting to see what Congress will do about the 1971 Department of Commerce Metric Study Report.     

Emission Standards for Particulates

Promulgation of standards of performance under Section 111 and national emission standards for hazardous pollutants under Section 112 of the Clean Air Act is the responsibility of the Emission Standards and Engineering Division of EPA. The problems encountered and the bases used are examined.     

The Denver Winter Aerosol: A Comprehensive Chemical Characterization

The sampling and chemical analysis of the ambient aerosol collected in Denver, CO, for a 40-day period during November and December, 1978 are described in this report. Parameters included 12-hr TSP measurements, 24-hr respirable and inhalable mass measurements, and 4-hr measurements of mass and chemical species (NO₃?, SO₄ =, NH₄ +, organic and elemental carbon as well as 13 chemical elements) in two size fractions i.e., less than 2.5 μm diameter (fine fraction) and larger than 2.5 μm diameter (coarse fraction). On the basis of the chemical analyses, it was possible to account for all particulate mass in both size fractions. In the fine fraction, the major constituents were organic carbon (21.6%), NH₄NO₃ (20.0%), elemental carbon (15.3%), (NH₄)₂SO₄ (13.6%), and the remainder consisted primarily of soil-like material, lead salts, and adsorbed water. Three quarters of the coarse fraction consisted of soil-like material, with the remainder composed of the same species that dominated the fine fraction.