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Biomedical subjects

E B Dawson

Publications and source records attributed to E B Dawson.

At least 37 records · Page 2Linked to original sources
PubMed1989

Serum zinc changes due to iron supplementation in teen-age pregnancy.

Serum zinc and iron concentrations in a group of pregnant teen-agers supplemented with a multivitamin were compared during pregnancy with a group supplemented with a multivitamin containing 18 mg Fe. Serum measurements were at 13 wk of gestational age (prestudy) and during supplementation at 20, 32, and 38 wk, delivery, and 4 and 12 wk postpartum. Hematocrit measurements were used to adjust the measured metal concentrations for the diluting effect of the normal blood-volume increase. The non-Fe-group mean, adjusted serum Zn concentrations showed no change, but the serum Fe decreased to 28% below prestudy concentrations at 38 wk. In contrast, the Fe-supplementation group showed a progressive increase in Fe concentrations to a maximum of 38% above prestudy concentrations at 4 wk postpartum and a 35% decrease from prestudy Zn concentrations during the third trimester. The results of this study suggest that 18 mg Fe/d is adequate supplementation for nonanemic teen-age pregnancy and depresses the serum Zn concentration.

Adolescent↗
PubMed1989

Serum ferritin levels after multivitamin iron ingestion during teenage pregnancy.

The postabsorptive serum ferritin levels following normal dosages of prenatal multivitamin/multimineral supplements were studied in 17 pregnant teenagers, whose fetuses were between 16 and 20 weeks gestational age. The purpose of the study was to determine the effect of a single oral dose of differing prenatal multivitamin/multimineral tablets containing 60 or 65 mg of elemental iron on the postabsorptive serum ferritin levels. Each woman was randomly tested following the ingestion of one of three different tablets, both in a fed and a fasting state. Blood samples were obtained for ferritin measurement immediately prior to ingestion of the prenatal tablet, with or without a standard meal, and at 1, 3, 6, and 8 hours postabsorption. The group mean serum ferritin levels increased dramatically during the fasting state following ingestion of the Stuart Prenatal tablet and decreased when the Stuartnatal 1 + 1 or Materna 1.60 was ingested. The opposite results were observed when the tablets were ingested postprandially. The results of the study indicate that Stuart Prenatal was most suitable for consumption while fasting (ie, at the hour of sleep), and both Stuartnatal 1 + 1 and Materna 1.60 with a meal.

Adolescent↗
PubMed1988

Bioavailability of iron in prenatal multivitamin/multimineral supplements administered to pregnant teenagers.

Absorption of elemental iron from three single-daily-dose prenatal multivitamin/multimineral supplements was compared in bioavailability studies of subjects under fasting and postprandial conditions. Each of the supplements (Stuartnatal 1 + 1, Stuart Prenatal, and Materna 1.60) contained 60 or 65 mg of iron. The subjects, teenagers in the second trimester of pregnancy, were assigned to the fasting or postprandial conditions at intervals of three to seven days. For the postprandial condition, subjects took the supplement after eating a standardized meal that had been designed to provide a minimal amount of iron and no caffeine (which inhibits iron absorption); blood was drawn at 0, 1, 3, 6, and 8 hours. Bioavailability studies showed that all three supplements provided adequate levels (at least 3.5 mg) of absorbed iron when taken postprandially. The highest quantity of net iron transport as well as the most rapid intestinal transport in either condition was yielded by Stuartnatal 1 + 1 taken in the fasting state. In the postprandial condition, Materna 1.60 demonstrated the fastest transport time and highest net iron transport; when given to a subject in the fasting condition, however, this supplement provided less than the recommended 3.5 mg of absorbed iron. These results suggest that iron absorption is influenced by supplement formulation as well as the presence or absence of food. Considering variations in compliance when iron is to be taken on an empty stomach as well as variable absorption in the fasting state, the most reliable supplementation would appear to be achieved by instructing pregnant women to take multivitamin/multimineral supplements at mealtime.

Absorption↗
PubMed1987

Protection of maternal iron stores in pregnancy.

Forty-two healthy young women, less than 16 weeks pregnant, with normal hematologic status, were selected at random to receive either a multivitamin/multimineral with 65 mg of iron or one without iron. During pregnancy and the puerperium, a full hematologic evaluation of the iron, folate and B12 status was performed. Those receiving the multivitamin without iron had significantly lower mean serum ferritin levels (P less than .05). During the study, 9 of these 21 noniron subjects (43%) failed to maintain an acceptable hemoglobin level (greater than 11.0 g/dL) and were medicated with 110 mg ferrous iron daily. Use of the multivitamin/multimineral supplement with iron during pregnancy and for 12 weeks postpartum maintained maternal iron stores, eliminated the need for additional iron medication and prevented the development of iron deficiency anemia. This 36-week longitudinal evaluation demonstrated the need for iron supplementation during pregnancy and for three months postpartum. Measurements of serum ferritin at 16-20 weeks of pregnancy will detect hematologic risk in young pregnant women not identified by usual hematologic assessments. The results of this study show that adequate maternal iron stores during pregnancy and the puerperium cannot be maintained by prevailing dietary patterns and therefore that iron supplementation is essential.

Adult↗
PubMed1983

A comparison of serum free estriol with spontaneous urine total estrogen and estrogen/creatinine ratio.

A mathematical comparison was made between the serum free estriol levels, the urine total estrogen, and the total estrogen/creatinine ratio in 83 pregnant women during the last trimester of pregnancy. The blood serum and spontaneous urine samples were obtained simultaneously, and each woman was sampled once. The serum estriol was measured by radioimmunoassay and the urine estrogen levels measured by the aqueous fluorometric Kober technique. The group averages of the three different measurements paralleled each other throughout the third trimester. Linear regression and correlation studies of the measured levels for each subject by the different methods were statistically significant (P less than or equal to 0.0001). The correlation factor between serum free estriol and spontaneous urine total estrogen was +0.5991, and between serum free estriol and the spontaneous urine total estrogen/creatinine ratio was +0.8086. The very high correlation between the two urine and the serum method suggest that spontaneous urine samples may be used to measure estrogen changes during pregnancy.

Adolescent↗
PubMed1982

Tissue distribution of lead in rat pups nourished by lead-poisoned mothers.

Lead accumulation was studied in rats treated with Pb through the dam's milk from birth to weaning. Dams of experimental litters received lead acetate in drinking water, while dams of control litters received a sodium solution. Fluid consumption by dams and pup weight were monitored daily. No differences were seen in the dams' fluid consumption or in mortality or growth rate of pups. Rats were sacrificed after 5, 10, 16, or 21 d of Pb treatment, or 3 and 3.5 mo after weaning. Samples of heart, brain, liver, kidney, intestine, and bone were solubilized in concentration nitric acid and analyzed for Pb by atomic absorption spectrophotometry. Nitric acid digests of blood samples from pups 10 and 21 d old and from animals allowed a Pb-free period of 3-3.5 mo after treatment were also analyzed for Pb concentration. Levels of Pb in all tissues analyzed progressively increased during the first 10 d of treatment. After the Pb-free period only bone Pb concentration remained elevated. The results indicate that treatment of lactating dams is an efficient method of producing chronic Pb exposure of rat pups. The results also provide a means of comparing studies of Pb toxicity in which different treatment paradigms are used.

Animal Population Groups↗
PubMed1982

Effects of hemodialysis and dimercaprol in acute dichromate poisoning.

A 22-month-old infant died after ingesting sodium dichromate his father had brought from work. Treatment included folic acid and dimercaprol administration, hemodialysis, and exchange transfusion. To evaluate this treatment, four dogs were hemodialyzed after receiving intravenous sodium dichromate: their dialyzer chromate clearance was similar to their renal chromate clearance and their dialyzer chromate clearance was not significantly different before or after dimercaprol administration. This and other cases in the literature indicate that although chromate poisoning is often fatal, supportive care, forced diuresis, and chelating agents may be helpful. Hemodialysis may be required if renal failure occurs. Awareness of toxicity and prevention remain the most important approaches.

Acute Disease↗
PubMed1979

Apparent effect of ascorbic acid medication on semen metal levels.

The apparent effect of ascorbic acid therapy for nonspecific spermagglutination on semen levels of ascorbic acid as well as macro- and micrometals was determined in 20 men (ages 25 to 38). Pretreatment diagnosis was based on infertility and relatively low ratings in sperm density, motility, motility index, and semen volume, and were associated with large numbers of abnormal sperm, sperm precursors, and leukocytes. The pretreatment levels of ascorbic acid, sodium, iron, potassium, zinc, manganese, lead, magnesium, and copper were measured in each patient's semen and compared with levels following 60 days of dietary vitamin C supplementation (1.0 gm/day). Analysis of the vitamin C preparation prescribed revealed that each subject was given an impure ascorbic acid medication to supplement a normal diet. Therefore, the significant increases in levels of ascorbic acid and metals in semen following therapy could not be attributed to ascorbic acid alone, nor, similarly, the improved physical parameters of each subject's semen following therapy; no apparent spermagglutination and restored fertility may be due to the interaction of ascorbic acid with cations found in semen.

Adult↗
PubMed1978

Relationship of metal metabolism to vascular disease mortality rates in Texas.

The annual mortality rates for 1968 of six types of cardiovascular diseases among those persons over 45 years of age in 24 Texas communities were compared with respective community drinking water and urine metal levels of calcium, magnesium, potassium, lithium, strontium, and silicon. Numerous inverse correlations were found between mortality rates and the levels of various metals in both drinking water and urine. Positive correlations were also observed between several of the mortality rates and the ratio of the concentration of sodium to that of the other metals in both water and urine. Mean community urinary levels of lithium, magnesium, strontium, and silicon showed a direct correlation to the levels of exposure via the drinking water. The results of this study suggest that calcium, magnesium, lithium strontium, and silicon may protect against cardiovascular mortality; possibly, by competing with sodium and potassium for transport in the intestinal lumen, increasing excretion of sodium, or other mechanism.

Calcium↗
PubMed1976

Effect of oral contraceptives on rhythmic urinary metal excretion.

Thirteen women, six of whom were using oral contraceptive agents, between the ages of 23 and 34 years, free from illness, and without a previous clinical history of menstrual abnormality, were studied with chronobiological methods for circadian (about 24 hour) patterns of metal and creatinine excretinine excretion. Circadian rhythms were detected for the excretion of lithium, potassium, iron, sodium, copper, and creatinine. Statistically significant by lower 24 hour excretion (mesors) of lithium, potassium, and iron was detected for the subjects using oral contraceptive agents. Although all women adhered to nearly identical activity-rest (synchronization) schedules, the peak times (acrophases) of the metal excretory rhythms for oral contraceptive users were phase delayed by about two hours.

Adult↗