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Biomedical subjects

N Jackson

Publications and source records attributed to N Jackson.

At least 109 records · Page 6Linked to original sources
PubMed1981

A study of the effects of dietary added cupric oxide on the laying, domestic fowl and a comparison with the effects of hydrated copper sulphate.

1. An experiment is reported in which copper, as cupric oxide, was fed to two breeds of laying hen for 336 d at levels equivalent to 150, 300, 450, 600 and 750 mg added Cu/kg diet. The results obtained were compared with those found using similar diets to which the Cu was added as CuSO4.5H2O. 2. Addition of the CuO had no effect on food intake, food conversion efficiency, body-weight or egg production. The CuSO4 addition caused the quadratic response of food intake and the adverse effects on food intake, egg production and body-weight noted in previous experiments. 3. The CuO had no effect on liver, kidney, ovary, oviduct or gizzard weight per unit body-weight while the CuSO4 decreased these with the exception of gizzard weight which was significantly increased. 4. CuO addition did not affect liver Cu concentration but CuSO4 caused a substantial increase of liver Cu especially at the 750 mg Cu/kg level of addition. 5. CuO addition had no effect on liver lipid concentration but this was depressed at the highest level of CuSO4 addition. Effects on individual fatty acids are presented but no specific conclusions have been reached.

Adipose Tissue↗
PubMed1981

Whole brain tyrosine hydroxylase activity during the development of deoxycorticosterone acetate-1% sodium chloride-induced hypertension in rats.

Water was chosen as the optimal medium for the extraction of tyrosine hydroxylase (TH) from rat brain. Determination of TH activity in crude homogenates failed to exhibit a linear relationship between enzyme concentration and measured activity, however, when a supernatant was used, a linear relationship existed. At a time when TH activity is maximally increased in the locus coeruleus after reserpine treatment (Reis et al 1975; Zigmond.1979) (2.5 mg kg-1 day-1 for 3 days, kill 24 h after last dose) we could detect no alterations in whole brain TH, however if treatment continued for 4 days and animals were killed 72 h after the last dose it was possible to detect increases in TH activity in various brain regions. These results suggest that local changes in brain TH activity are not revealed in measurements made on whole brain. The early rise in blood pressure, following the administration of deoxycorticosterone acetate (doca) and 1% NaCl to male Wistar rats, was accompanied by bradycardia. Whole brain Th activity was determined in these hypertensive animals 6-21 days after the commencement of treatment and the results failed to confirm the reported elevation of TH activity (Rylett et al 1976). The results are discussed with reference to the TH assay employed.

Animals↗
PubMed1981

Age of initial drug experimentation among white and non-white ethnics.

Students in four cities completed a questionnaire regarding their ethnic background and drug use patterns. From this information, comparisons in age of initial drug experimentation among ethnic groups and races were made. The results indicated significant differences in actual age of experimentation among ethnic groups, as well as differences in other general pattern relating to age of first drug use. A comparison of Whites to non-Whites showed little difference in ages of initial drug experimentation. It was concluded that ethnicity, more so than mere race, was related to age of first use of drugs.

Adolescent↗
PubMed1980

Effects of level of dietary copper sulphate and period of feeding on the laying, domestic fowl, with special reference to tissue mineral content.

1. A cereal-based diet containing 7.6 mg copper/kg was fed ad lib. to laying hens for up to 48 d. Four other groups were given the control diet to which was added hydrated copper sulphate to provide 250, 500, 1000 and 2000 mg added Cu/kg. 2. Hens were killed on day 0 and after 3, 6, 12, 24 and 48 d. Records were kept of body-weight, food consumption, egg production and egg weight. 3. After slaughter blood haemoglobin, packed cell volume, serum Cu and aspartate aminotransferase (AAT; EC 2.6.1.1) were measured. The liver, kidneys, a sample of breast muscle, oviduct, ovary and gizzard were weighed. Gizzard, spleen, liver and kidney tissue were examined histologically. 4. The Cu, zinc and iron concentrations of liver, kidneys and breast muscle and the manganese concentrations of liver and kidneys were determined. 5. Body-weight loss occurred at 500-2000 mg added Cu/kg diet. Egg production was depressed by level of added Cu and period of time on the Cu-containing diets. 6. Mean liver, kidney, oviduct and ovarian weights per unit body-weight were depressed by Cu in the diet and the effect increased with period of time on the diets. Mean gizzard weight per unit body-weight was increased by dietary added Cu and by time. 7. Cu concentrations in the liver were increased by dietary level of added Cu and period of time on the diet. Zn concentration in liver increased at 1000 and 2000 mg added Cu/kg diet and liver Fe concentration was increased at these levels. Histological examination of the gizzard indicated that the Cu content of the gizzard lining increased with dietary added Cu.

Animals↗
PubMed1980

Effects of withdrawal of copper sulphate from the diet of the mature domestic fowl with special reference to production and tissue mineral content.

1. Cereal-based diets containing 0, 500, 1000 or 2000 mg added copper/kg were offered ad lib. to laying hens for 8 weeks. All the hens were subsequently offered the control diet (no added Cu, 7.5 mg Cu/kg). 2. Hens from each treatment were killed at 0, 2, 4, 6 and 8 weeks after removal of the Cu-supplemented diets. Records were kept of body-weight, food consumption and egg production. 3. After slaughter, blood haemoglobin, packed cell volume, serum Cu and asparate aminotransferase (AAT; EC 2.6.1.1) were assayed. The liver, kidneys, oviduct, ovary, gizzard, caeca and bile duct were weighed. 4. Mean Cu, zinc and iron concentration of liver, kidneys and caecal contents were determined. 5. The adverse effects of Cu on body-weight, food intake, egg production and liver, oviduct, ovary, gizzard and bile weights were rapidly reversed by removal of added Cu from the diets. 6. Greatly enhanced liver Cu concentration resulted from feeding the high-Cu diets but this effect was rapidly reversed on removal of added Cu from the diets. Liver Fe concentration showed a less marked but similar effect. 7. The Cu concentration of caecal contents was increased by Cu supplementation and rapidly reduced after withdrawal of the Cu-containing diets.

Animals↗
PubMed1979

Effects of the protracted feeding of copper sulphate-supplemented diets to laying, domestic fowl on egg production and on specific tissues, with special reference to mineral content.

1. Two experiments are reported. In both experiments a cereal-based diet containing 5 mg copper/kg was fed to two breeds of laying hens for 336 d. In Expt 1 four other groups were given this diet with the addition of CuSO4.5H2O to give added levels of 200, 400, 600 and 800 mg Cu/kg diet. In Expt 2 the levels of added dietary Cu used were 100, 200, 300 and 400 mg/kg. 2. In Expt 1 records were kept of food intake, water intake, body-weight and egg production for eight 28 d periods and body-weight and egg number only were recorded for the full twelve periods. In Expt 2 full records, excluding water intake, were taken for all twelve periods. 3. Food and water intake showed a quadratic response to level of added dietary Cu, being enhanced at lower levels and depressed at higher levels of addition. 4. There was a quadratic response of total egg weight, mean egg weight and egg number to added dietary Cu. In Expt 1 egg number was maximum at 235 mg added Cu/kg diet for Warren Studler SSL (breed 1) and at 170 mg added Cu/kg diet for Shaver 288 (breed 2). In Expt 2 no breed effect occurred, the maximum egg number being calculated to occur at 176 mg added Cu/kg diet. 5. Depression of body-weight gain occurred at high levels of Cu addition. The depression of liver and oviduct weight found at high levels of addition appeared to be directly related to body-weight. A marked amount of feather loss also occurred at a high inclusion of CuSO4 in the diet. 6. The reproductive systems of the hens did not appear to be adversely affected at the levels of additive used. Gross and microscopic examination of specific tissues revealed no pathological effects although gizzard and intestinal weights were increased and caecal weight decreased by high levels of added Cu. THose aspects of the blood chemistry examined did not reveal any consistent effect between the two experiments. 7. The liver Cu analyses indicate that between 600 and 800 mg added Cu/kg diet the liver Cu concentration rises sharply. Both liver Fe and Zn concentrations showed a positive linear response to added dietary Cu. In the kidney Cu and Zn concentrations were increased but only to a limited extent, while the concentration of Fe was unaffected.

Animals↗
PubMed1979

The effects of folate deficiency and oestradiol administration on the plasma free amino acid concentrations of the immature hen.

1. Free amino acid concentrations were measured in the blood plasma of immature pullets receiving a folate-deficient diet and injected with folate and/or oestradiol, with appropriate controls. 2. Folate deficiency caused a decrease and oestradiol administration an increase in the plasma concentration of most of the amino acids studied. 3. Plasma glycine concentration increased in foliate deficiency and decreased with oestradiol treatment. 4. All the observed effects could not be readily explained in terms of the known metabolic role of folate in amino acid metabolism. 5. The results did not indicate that the role of folate in amino acid metabolism was significant in the inhibition of oestradiol-stimulated oviduct growth.

Amino Acids↗
PubMed1977

Ion-exchange chromatographic study of amino acid degradation during hydrolysis of avian protein.

The losses of amino acid during acid hydrolysis of oviduct magnum protein from the domestic fowl have been measured using a Technicon TSM-1 amino acid analyser. The results were subjected to statistical analysis and a linear regression was obtained for each amino acid investigated. Methionine, in the presence of oxygen, did not exhibit significant degradation. A loss of 5.5% was found for phenylalanine after 24 h of hydrolysis under nitrogen. It is suggested that the results could be applied to animal proteins from tissue of similar composition but not to analysis of protein from plant materials.

Amino Acids↗
PubMed1977

The effect of dietary copper sulphate on laying performance, nutrient intake and tissue copper and iron levels of the mature, laying, domestic fowl.

1. A cereal-based diet containing 16 mg copper/kg was fed ad lib. to a group of laying hens for 35 d. Five other groups were given this control diet to which was added 120, 240, 480, and 1920 mg Cu/kg (as copper sulphate). 2. Records were kept of daily food intake, water intake and egg production. 3. After 35 d the hens were slaughtered and blood haemoglobin, packed cell volume, Cu and aspartate aminotransferase (EC 2.6.1.1) levels assayed. Liver, oviduct, kidney and breast muscle Cu and iron concentrations were measured. 4. Food and water intakes were depressed by the two highest levels of dietary Cu and water intake was increased by the diet with 240 mg added Cu/kg. Both food and water intake showed a quadratic relationship with the level of added dietary Cu. 5. Body-weight loss was increased by the addition of Cu and showed a significant linear relationship with the concentration of added Cu in the diet. Liver and oviduct weights were depressed at the two highest levels of Cu addition. 6. Liver and oviduct Cu and Fe concentrations were significantly increased by high dietary Cu and mean total liver and kidney Cu and Fe showed an increase although for the liver this was not statistically significant.

Animal Nutritional Physiological Phenomena↗
PubMed1975

Locoid trial.

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Administration, Topical↗