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Biomedical subjects

M Farmer

Publications and source records attributed to M Farmer.

At least 55 records · Page 3Linked to original sources
PubMed1986

Influence of dietary calcium on bone calcium utilization.

In Experiment 1, 10 microCi 45Ca/day were administered to 125 hens for 10 days. Hens were then allocated to five treatments with calcium levels ranging from .08 to 3.75% of the diet. In Experiment 2, hens with morning oviposition times were randomly allocated to 11 treatments that were periods of time postoviposition ranging from 6 hr to 24 hr, in 2-hr increments (Experiment 2). At the end of each 2-hr period, eggs from 25 hens were removed from the uterus. The 18-, 20-, and 22-hr treatments were replicated three times. In Experiment 3, hens were fed either ad libitum or feed was withheld the last 5 or 6 hr before oviposition. In Experiment 4, hens were fed 10 microCi of 45Ca for 15 days to label skeletal calcium. Hens were divided into two groups and fed a .08 or 3.75% calcium diet for 2 days. On the second day, 25 hens fed the 3.75% calcium diet were intubated with 7 g of the same diet containing .5 g calcium at 1700, 2100, 0100, 0500, and 0700 hr. The measurements used were egg weight, shell weight, and 45Ca content of the egg shell. Results indicated a significant linear or quadratic regression of dietary calcium levels on 45Ca accumulation in eggshells and eggshell weight (Experiment 1). As the calcium level of the diet increased, eggshell weight increased and 45Ca recovery decreased. Utilization of skeletal calcium for shell formation ranged from 28 to 96%. In Experiment 2, the rate of shell calcification was not constant throughout the calcification process but varied significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Influence of dietary ingredients on calcium utilization in the laying hen.

Experiments were conducted to evaluate the benefit of calcium supplementation with or without other dietary ingredients on egg shell quality. A total of 250 Hyline hens, 44 weeks of age, were randomly divided among five treatments (Experiment 1). The dietary treatments were as follows: Treatment 1, controls (C) were fed a 3.5% calcium diet ad libitum; Treatment 2, hens were fed a .08% calcium diet (LC); Treatment 3, hens were intubated with limestone following 24-hr consumption of .08% calcium diet (LCI); Treatment 4, feed removed for 24 hr (NF); Treatment 5, feed removed for 24 hr and hens then intubated with limestone (NFI). All diets were restored to the control calcium level after 48 hr. Experiment 2 was identical to Experiment 1 except Dekalb XL hens, 50 weeks of age, were used. Eggs were collected daily for 5 days for egg specific gravity, egg weight, and shell weight determinations. Forty hens were sacrificed in Experiment 2 at 48 hr into the experiment to measure calcium distribution in the gastrointestinal (GI) tract and feces. Results indicated that hens fed the LCI treatment produced eggs with significantly higher specific gravity and heavier shells than hens given limestone with an empty GI tract. The calcium analysis of the GI tract revealed that much of the calcium supplement did not move beyond the gizzard in hens fed the NFI treatment. It was concluded that hens not only needed other nutrients for maximum utilization of dietary and skeletal calcium, but other nutrients or dry matter may also be needed to facilitate the passage of calcium from the gizzard.

Animal Feed↗
PubMed1986

Influence of time of calcium intake on bone and dietary calcium utilization.

Sixteen hens, 67 weeks old, having oviposition times at 0700 +/- .25 hr, were used in Experiment 1. Hens were randomly divided into two treatments and fed a .08% calcium diet following oviposition. For 5 days, at either 0800 (AM) or 1600 (PM) hours, hens received 3.65 g of calcium by intubation. On Day 1, the calcium source contained 25 microCi of calcium-45 (45Ca). Eggs and excreta were collected daily for 45Ca analysis. Experiment 2 was similar to Experiment 1 except that 34-week-old hens were used. Calcium-45 activity of the egg shell, excreta, serum, and total contents of the gastrointestinal (GI) tract was determined. Results of Experiments 1 and 2 indicated that hens receiving their daily supply of calcium in the PM deposited significantly more of that day's dietary calcium on the following day's egg than hens receiving calcium in the AM. Excreta from the AM-treated hens contained significantly more 45Ca than that from the PM-treated hens during the first 24 hr in both experiments. In Experiment 2, the quantity of 45Ca in serum and GI tract contents was significantly higher from hens in the PM treatment. It was concluded that hens utilized significantly more calcium for egg shell formation from PM consumption rather than AM consumption and, therefore, were less dependent on bone reserves when the calcium was consumed in the PM.

Animals↗
PubMed1985

Calcium and its relationship to excess feed consumption, body weight, egg size, fat deposition, shell quality, and fatty liver hemorrhagic syndrome.

In Experiment 1, Hyline W36 caged hens were fed diets containing 1.7, 2.9, 3.5, and 4.1% calcium for 10 and 16 weeks. In Experiments 2 and 4, Dekalb XL and Hyline W36 pullets were fed diets containing 1.0, 1.7, and 3.75% calcium for 3 weeks (Exp. 2) or until 25 pullets from each group laid 7 eggs (Exp. 4). In Experiment 3 and 5, Dekalb and Hyline hens were fed diets containing 1.5 (Dekalb only), 1.75, 2.25, 2.75, and 3.75% calcium for 8 weeks. Criteria were liver, fat pad, egg and shell weights, egg specific gravity, production, feed consumption, liver fat and fatty acid composition, liver hemorrhage score, and body weight. As percent dietary calcium decreased, Hyline birds (Exp. 1, 4, and 5) had increased liver fat, body weight (except Exp. 4), and feed consumption, but egg specific gravity and shell weight decreased. Reduced dietary calcium levels had no effect on egg production in Experiment 1 but significantly reduced production in Experiment 5. Liver hemorrhage score significantly increased as percent dietary calcium decreased (Exp. 1). As dietary calcium decreased, Dekalb pullets (Exp. 2) had increased feed consumption, fat pad weight, and liver hemorrhage score. There was no increase in liver fat. However, in Dekalb hens (Exp. 3), feed consumption and egg production were significantly decreased as dietary calcium decreased. It is concluded that overconsumption caused by feeding pullets or hens inadequate calcium had no beneficial effect on egg size or egg production and, depending on strain, increased liver fat, liver hemorrhage score, body weight, and fat pad weight.

Adipose Tissue↗
PubMed1984

Mass spectral properties of volatile derivatives of thyronine (T0) and use of these in the study of thyronine excretion in eu-, hyper- and hypothyroidism.

The mass spectral properties of four classes of derivatives of thyronine are discussed ( oxazolidinone , O-methyl oxazolidinone , O-acetyl oxazolidinone and N,O- diheptafluorobutyryl methyl ester). An assay for thyronine in human urine is described based on the N,O- diheptafluorobutyryl methyl ester. Results of T0 excretion in euthyroid humans were compared with those obtained previously using an assay based on the O-acetyl oxazolidinone derivative. Patients with frank hyperthyroidism had significantly higher T0 excretion than euthyroid subjects (2 alpha less than 0.002) and hypothyroid patients lower T0 excretions than euthyroid subjects (2 alpha less than 0.002). Some overlap between the two pathological ranges and the normal euthyroid range was evident.

Humans↗
PubMed1983

3,5-Diiodotyrosine excretion in human urine in individuals of differing thyroidal status.

The urinary excretion of 3,5-diiodotyrosine was determined in euthyroid, hypothyroid and hyperthyroid individuals using a sensitive gas chromatographic mass spectrometric assay. This involved a multi-step extraction of the amino acid from urine (mean efficiency 28 +/- 5.7%) then conversion to the N,O-diheptafluorobutyryl methyl ester. The fragmentation of the derivative is discussed. Although the mean excretions in the two pathological states were significantly different from that of euthyroid individuals (P less than 0.01 in both instances) there was considerable overlap with the normal range.

Diiodotyrosine↗
PubMed1983

Calcium metabolism in broiler breeder hens. 1. Calcium status of the digestive tract of broiler breeders throughout a 24-hour period.

Dry matter and calcium content of the digestive tract were determined on two groups of broiler breeders during a 24-hr period. The individually caged hens were fed either ad lib or restricted to 122 g of feed during a 4-hr feeding period each day from 0700 to 1100 hr. The hens received artificial light from 0700 to 2300 hr. On Day 14 of the feeding program a total of 100 hens, 10 from each group, were necropsied at selected intervals (0700, 1100, 1900, 2300, 0300 hr), and the contents of the various segments of the digestive tract and feces were collected and analyzed for dry matter and calcium. The calcium analysis also included any endogenous excretions and, therefore, absorption values are apparent. Hens restricted to 122 g feed per day had only 51.7% of the dry matter and 64.2% of the calcium consumed during the 4-hr feeding period remaining in the digestive tract at 1100 hr. By 2300 hr only 20.6% of the feed and 28.1% of the calcium remained. Hens had only approximately 14% (14.2 g) of their total dry matter intake and 16% (.70 g) of the calcium available for absorption from 0300 hr. The ad lib group, with an average intake of 171 g feed per day, had consumed only 26% of their daily feed intake by 1100 hr. Fifty-five percent of the dry matter consumed and 22% of the calcium remained in the digestive tract at 1100 hr. It was concluded that broiler hens restricted to morning feeding do not maintain a constant and equal metering of dry matter or calcium from the crop into the digestive tract throughout a 24-hr period.

Animals↗
PubMed1983

Calcium metabolism in broiler breeder hens. 2. The influence of the time of feeding on calcium status of the digestive system and eggshell quality in broiler breeders.

Experiments were conducted to determine the influence of time of dietary calcium intake on eggshell quality in broiler breeder hens. In Experiment 1, 60 hens were randomly divided among three treatment groups. The control group received 155 g feed (3.1% calcium) per day at 0800 hr whereas the morning- (a.m.) and evening-fed (p.m.) treatments received a .42% calcium diet (155 g/bird) and were intubated with 4.2 g calcium at 0800 or 1600 hr, respectively. Egg weight, shell weight, and specific gravity were determined at 3-day intervals for 15 days. In Experiment 2, 150 breeder hens were randomly divided among two treatment groups. They were fed 122 g per hen during a 2.5-hr feeding time at 0700 to 0930 or 1530 to 1800 hr. Eggs were collected for egg weight, shell weight, and specific gravity determinations. At the end of the 5th week, 10 hens from each treatment group were sacrificed at various times throughout a 24-hr period and the contents of each segment of the GI tract and feces were analyzed for moisture, dry matter, and calcium. In Experiment 3, two commercial broiler-breeder houses with 5,000 hens each were used. They were fed 132 g/hen per day at 0530 hr daily with water provided ad lib. The feeding time of one house was moved forward by 2 or 2.5 hr per day until the feeding time was 1600 hr. Eggs were collected for 2 weeks following pretreatment data and values determined for specific gravity. Eggs were also candled at 7 days incubation to determine embryonic mortality and fertility. Hens intubated at 0800 hr with their daily supply of calcium did not maintain shell quality equivalent to controls (Experiment 1). However, hens intubated at 1600 hr had no difficulty maintaining shell quality. Hens fed at 1530 hr had significantly better shell quality during all weeks tested compared to hens fed at 0700 hr (Experiment 2). The p.m.-fed hens had 66.9% more calcium available at 1800 hr (2.07 vs. 1.24 g) compared to a.m.-fed hens. Hens fed at 1600 hr in the commercial houses (Experiment 3) had significantly better eggshell quality (specific gravity) than hens fed at 0530 hr. There was no significant difference in percent embryonic mortality or percent fertility when eggs were candled after 7 days of incubation. It was concluded that p.m.-fed hens had significantly more calcium available during the stages of eggshell calcification. The result was significantly better eggshell quality.

Animals↗
PubMed1980

Calculations of the circular dichroism of adenosine derivatives constrained in the syn form.

The rotational strengths of the four longer wavelength transitions, B(2u), B(1u), and the two E(1u), of adenosine derivatives constrained in the syn form have been investigated theoretically and experimentally. The theory combines a complete neglect of differential overlap version S (CNDO/S) description of the base with a generalized bond exciton method by means of a matrix method. Rotational strength wheels for these transitions showing the rotational strength as a function of the glycosidic rotational angles are presented and sector rules discussed. Similar sector rules are predicted for purine nucleoside derivatives containing the 6-amino substituent, regardless of heteroatom content at positions 1 or 3 of the base. The sector rules for the B(2u) rotational strength of purine nucleosides lacking the 6-amino substituent are strongly influenced by aza substitution. The circular dichroism spectra of 3-deazaadenosine, 8-(alpha-hydroxyisopropyl)-adenosine, and other purine nucleosides having a strong preference for the syn conformation are presented and compared with the theoretical results.

Journal Article↗
PubMed1977

Amino acid sequence of human platelet factor 4.

Human platelet factor 4, a protein that binds heparin, has been purified to apparent homogeneity and the complete amino acid sequence of the protein has been determined. The 70-residue polypeptide chain contains no methionine, tryptophan, or phenylalanine, and contains only a single tyrosyl residue. The sequence analysis demonstrates a highly negatively charged amino-terminal region. The carboxyl-terminal region of the polypeptide is unusual in that it contains a repetitive clustering of positively charged and hydrophobic pairs of amino acids; preliminary evidence suggests that this domain may play a role in the binding of heparin.

Amino Acid Sequence↗