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Biomedical subjects

G N Biddle

Publications and source records attributed to G N Biddle.

8 recordsLinked to original sources
PubMed1986

A survey of the concentrations of eleven metals in vaccines, allergenic extracts, toxoids, blood, blood derivatives and other biological products.

Approximately 85 samples of injectable biological products regulated by the Center for Drugs and Biologics of the United States Food and Drug Administration were surveyed for the presence of 11 elements, namely aluminum, arsenic, barium, cadmium, chromium, lead, mercury, selenium, thallium and zinc, by flame and flameless methods of atomic absorption spectrometry and flame emission spectrometry. The range of products tested included whole blood, red cells, plasma, normal serum albumin, antihemophilic factor, and other products derived from blood; allergenic extracts including honey bee venom and house dust allergenic extracts; vaccines such as measles virus vaccine and typhoid vaccine; and tetanus toxoid. The metal concentrations found in the majority of these products were low or undetectable. The metal levels varied from manufacturer to manufacturer, product and lot-to-lot of the same manufacturer's products. House dust allergenic extracts had the highest concentrations of arsenic (2.4 ppm), cadmium (0.28 ppm), chromium (0.6 ppm) and lead (1.5 ppm) found in the study. A high zinc concentration (24 ppm) in an immune serum globulin was attributed to the zinc-containing rubber stopper in contact with the product. A range of 0.36-3.30 ppm aluminum was found for seven 25% normal serum albumin samples from seven manufacturers. Values of 8.2, 17 and 18 ppm aluminum were found in one manufacturer's 25% normal serum albumin. These aluminum values appeared to be the result of an anomaly in this manufacturer's production that has not been repeated to date.

Allergens↗
PubMed1982

Toxicology of lead: primer for analytical chemists.

Through the years, considerable amounts of Pb have been mobilized into our environment, and Pb may represent one of the most ubiquitous of all toxic metal contaminants. Excluding occupational exposure, the general population receives almost 70% of its total exposure to Pb from food. Other important sources of exposure include drinking water and air; minor sources include tobacco products, decorative glassware, and other types of food utensils. For young children, ingestion of Pb-containing soil or dust via normal hand-to-mouth activity or, in extreme cases, pica (the abnormal intake of soil, paint chips, etc.) may represent a significant source of exposure. The severity of clinical manifestations of Pb toxicity depends on both duration and intensity of exposure. Infants and young children are more susceptible to the effects of Pb than are adults. Although there is little debate over the serious consequences of acute, high-level Pb exposure, both controversy and concern have been expressed about the degree of risk that may be associated with chronic exposure to Pb levels that are closer to contemporary levels in the general environment. This concern is particularly high with regard to infants and young children, who may undergo Pb-induced changes that have long-term neurological impact (e.g., learning deficits, gross and/or fine motor dysfunction, impaired cognitive abilities).

Chemistry Techniques, Analytical↗
PubMed1975

Labile nitrogen reserves in the ruminant. Metabolic changes in growing cattle employing a nitrogen depletion-repletion treatment.

A metabolism study was conducted in which eight growing steers were subjected to a nitrogen (N) depletion-repletion regime. Three consecutive time periods were used to standardize, to deplete, and to replete body N. Diets fed in the respective periods provided by analysis 6 and 16% protein equivalent, respectively, from corn gluten or urea. Metabolic parameters were monitored during weeks 3 and 5 of standardization, weeks 1, 3, and 5 of depletion, and weeks 1 through 7 of repletion. Growth-rate trends started to deviate downward from linearity during the last 2 weeks of depletion; a trend that was not reversed until week 3 of repletion. Apparently digested N was defined by regression equations in which truly digested N was 94 and 83% of ingested N and metabolic fecal N totaled 0.64 and 0.48 g N/100 g ingested dry matter for corn gluten and urea N, respectively. The relationship between total urinary N losses and truly digested N was determined in which biological value equaled 60 and endogenous urinary N losses totaled 0.34 g N/kg0.60/day (equivalent to 0.040 g N/kg/day). Retained N decreased from 1.09 g during standardization to 0.16 g/kg0.60/day after 1 week of depletion. A subsequent improvement in retained N to 0.36 g in week 3 was followed by a decrease to 0.19 g/kg0.60/day after week 5 of depletion. In repletion, lowest and highest retained N occurred during weeks 1 and 4. Changes in retained N were produced by changes in urinary urea N excretion. Ammonia N accounted for 20, 21, and 24% of the total urinary N voided during standardization, depletion, and repletion. Except for urinary urea N losses that were greater and inversely related to fecal losses in urea-fed steers, dietary N source did not influence the excretion of ammonia, creatinine, or residual N.

Ammonia↗
PubMed1975

Labile nitrogen reserves and plasma nitrogen fractions in growing cattle.

The existence and magnitude of labile nitrogen (N) reserves were studied in growing cattle using a dietary N depletion-repletion technique. Blood parameters and urinary N excretion patterns were monitored. Blood hematocrit (Ht) did not respond to reduced ingested N until after week 3 of depletion at which time it began to fall. About 3 weeks of repletion regime was required before Ht values increased again. Plasma protein and albumin decreased from 6.05 and 2.70 g during standardization to 5.44 and 2.44 g/100 ml after 5 weeks of depletion and did not approach predepletion levels until week 6 of repletion. Plasma urea N decreased from 16 mg in standardization to 0.08 mg/100 ml in depletion and required 3 weeks of repletion treatment to attain a peak of 18 mg/100 ml. Labile N reserves were determined by integrating the areas from total urinary N excretion curves obtained during depletion and repletion periods. On a live body weight basis labile N represented 5.6% of total body N. When computed on an empty body weight basis (does not include weight of gastrointestinal tract), labile N totalled 6.0%. The magnitude of labile N stroes as a percentage of total body N was 44% greater in steers with a mean body weight of 280 kg compared with animals weighing 144 kg.

Animals↗
PubMed1975

Effect of sulfur-containing dietary supplements on gizzard lining erosions.

Three experiments were conducted with crystalline amino acid basal diets containing 5% isolated soy protein to ascertain the supplementary effect of sulfur-containing compounds on blood constituents and gizzard lining erosion. At the 0.40% methionine dietary level, the plasma albumin protein values were improved by supplements of sulfate and fishery products, whereas, the globulin values were variable. At the methionine content of 0.55%, the hematocrit value was also increased. Taurine, cysteic acid or fish meal ash did not improve the growth of chicks fed 0.45% methionine. Gizzard lining erosions were quite prevalent and severe when chicks were fed inadequate methionine and were improved considerably but not totally prevented by the 0.70 to 1.25% levels of sulfur amino acids.

Animal Feed↗