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Biomedical subjects

H Spencer

Publications and source records attributed to H Spencer.

At least 73 records · Page 4Linked to original sources
PubMed1984

Mineral and trace element content of vegetarian diets.

Lacto-ovo, lacto, and vegan vegetarian diets were analyzed for calcium, phosphorus, magnesium, zinc, iron, and nitrogen at four calorie intake levels ranging from 1,700 to 2,800 kcal/day. Diets containing dairy products had a high calcium and phosphorus content, ranging from 1,279 to 1,755 mg calcium and 1,378 to 2,160 mg phosphorus for the four calorie levels, respectively, and vegan diets contained less calcium, ranging from 612 to 810 mg. The magnesium content of all three types of vegetarian diets was adequate or high, ranging from 366 to 560 mg/day. The zinc content was lower than that of the RDA (15 mg/day), and was particularly low at the 1,700 calorie intake levels of all diets. The iron content of these diets varied widely and ranged from 12.7 to 22.7 mg. This study has shown that vegetarian diets planned and presented at the higher calorie intake levels contain adequate amounts of minerals and trace elements, whereas this is not the case at the 1,700 calorie intake level. This observation is of importance as the mineral and trace element content of relatively low calorie vegetarian diets would not supply sufficient amounts of these nutrients. In addition, the bioavailability of minerals and trace elements from these diets remains to be determined.

Calcium↗
PubMed1984

Magnesium absorption in human subjects from leafy vegetables, intrinsically labeled with stable 26Mg.

Collards, turnip greens, leaf lettuce, and spinach, grown in nutrient solution so that their Mg content was 80 to 90% 26Mg, were tested in ambulant male volunteers stabilized on a constant metabolic diet. The freeze-dried vegetables were incorporated in bran muffins in which the vegetables replaced part of the bran. Bran muffins without vegetables were consumed for breakfast each day. They were also used as a standard test meal to which the vegetable muffins were compared. All subjects participated in three consecutive isotope absorption tests: one of the standard test meal and two of the vegetables. The standard test was carried out after at least 30 days on the controlled diet. Subsequent tests of vegetables followed at 4-wk intervals. Each test meal contained 30 microCi 28MgCl2 and 50 mg stable 26Mg, the latter either as the intrinsic label of a test vegetable or as 26MgCl2 in solution taken with the standard bran muffins. Net absorption of both isotopes was measured to establish exchangeability and to determine relative Mg absorption from the vegetables. Exchangeability was 90% or higher from all meals tested. Relative Mg absorption was highest from collards and least from the standard test meal. Net absorption values ranged from 40 to 60%.

Feces↗
PubMed1984

Effect of calcium on phosphorus metabolism in man.

The effect of calcium on phosphorus metabolism was studied in adult males by determining phosphorus and calcium balances during three calcium intakes of approximately 200, 800, and 2000 mg/day. Each of these calcium intakes were given during two intake levels of phosphorus of approximately 800 and 2000 mg/day. In all studies, the addition of different amounts of calcium led to a significant decrease of the urinary phosphorus, a significant increase of the stool phosphorus, and significant improvement of the phosphorus balance irrespective of the phosphorus intake. Only in one study in which the calcium intake was increased from 230 to 831 mg/day during the high phosphorus intake of approximately 2000 mg/day were these changes not significant. During all calcium intakes, the decrease in urinary phosphorus was greater than the increase in stool phosphorus irrespective of the phosphorus intake. The apparent absorption of phosphorus decreased on increasing the calcium intake. The calcium balance was not adversely affected by increasing the phosphorus intake to 2000 mg/day during any of the calcium intakes.

Adult↗
PubMed1984

Effect of calcium and phosphorus on zinc metabolism in man.

Calcium and phosphorus have been shown to inhibit the availability of zinc for absorption in animal studies, but limited information is available on this subject in man. In the present study, the effect of both calcium and phosphorus on zinc metabolism was investigated in adult men by determining metabolic balances of zinc during three intake levels of calcium of 200, 800, and 2000 mg/day, and during two intake levels of phosphorus of 800 and 2000 mg/day. The analyzed dietary zinc intake was normal and was kept constant throughout all study phases. Increasing the calcium intake from 200 mg to two higher intake levels up to 2000 mg/day did not significantly change the urinary or fecal zinc excretions or the zinc balance. Also, increasing the phosphorus intake from 800 to a high intake of 2000 mg/day did not have any effect. The simultaneous use of the high calcium and high phosphorus intake also had no effect on zinc excretions and on the zinc balance.

Adult↗
PubMed1984

The pulmonary plasma cell/histiocytoma complex.

Twenty-seven pulmonary lesions have been reviewed both clinically and pathologically mainly by light microscopy. Almost all the lesions have shown features which were predominantly those associated with either a plasma cell granuloma or a histiocytoma. Both conditions arise from a common chronic inflammatory origin and form one disease complex. In almost every instance the lesions show some features characteristic of the other. In two malignant change had occurred. The light microscopic and electron microscopic characteristics of this complex of lung lesions are described. A possible aetiological cause is suggested. The many names that have been given to this group of pulmonary lesions in the past have led to confusion and failure to recognize their inflammatory nature.

Adult↗
PubMed1984

Calcium requirements in humans. Report of original data and a review.

Presently submitted and previously available data indicate that the recommended calcium requirement of 800 mg/day is inadequate for a large segment of the population, particularly the elderly. With an intake of 800 mg of calcium/day, calcium balance was only slightly positive, without consideration of dermal losses or other risk factors that may play a role in calcium bioavailability and calcium retention. A calcium intake of 1000-1200 mg/day is preferable, as calcium balance increased significantly when calcium intake was increased from 800 to 1200 mg/day; there was no further improvement in calcium balance on higher calcium intakes, up to 2300 mg/day.

Adaptation, Physiological↗
PubMed1984

Fluoride therapy in metabolic bone disease.

Multiple forms of treatment are used for osteoporosis, Paget's disease of the bone, and osteogenesis imperfecta. Because of the effect of fluoride (F) on bone, these bone conditions may benefit from F therapy. In the present study, the metabolic effects of two dose levels of F (20 and 45 mg, given as sodium fluoride) were studied on calcium (Ca) and F metabolism in patients with osteoporosis, whereas the effect of the 45-mg dose was studied in patients with Paget's disease. In patients with osteoporosis, the retention of F increased with increasing F intake, indicating F deposition in bone. However, only the 45-mg dose decreased urinary Ca excretion. F did not decrease fecal Ca excretion, indicating that the intestinal absorption of Ca did not improve during F therapy. This was confirmed in 47Ca absorption studies. The duration of F therapy was 3 months, utilizing the 45-mg dose. Clinically, the patients experienced relief of bone pain, and the onset of this change coincided with the decrease in urinary Ca. The 3-month course of treatment was sufficient for alleviation of clinical symptoms for many months and even years. In patients with Paget's disease, F supplements decreased urinary Ca and also resulted in relief of bone pain. F therapy for osteogenesis imperfecta resulted in decreased fracture incidence.

Calcium↗
PubMed1983

Further studies of the effect of a high protein diet as meat on calcium metabolism.

Previous studies in this Unit have shown that a high protein intake, given as meat, did not induce hypercalciuria, except for the initial and temporary increase in two subjects. In the present investigation the long-term effect of a high meat diet on calcium metabolism was studied for 78 to 132 days in four adult males and the short-term effect for 18 to 30 days in three subjects. Calcium and phosphorus balances and calcium absorption studies, using 47Ca as the tracer, were carried out. During the long-term high meat intake and during the short-term high meat studies, there was no significant change of the urinary or fecal calcium nor of the calcium balance. There was also no significant change of the intestinal absorption of calcium during the high meat intake. These long- and short-term studies have confirmed our previous results that a high protein intake, given as meat, does not lead to hypercalciuria and does not induce calcium loss.

Adult↗
PubMed1983

Pregnancy in patients after homograft cardiac valve replacement.

Thirteen pregnancies in ten patients with homograft cardiac valves resulted in 11 healthy infants, one spontaneous abortion, one elective termination of pregnancy, and the stillbirth of one member of a twin pregnancy. Two forceps deliveries and three cesarean sections were performed and routine antibiotic prophylaxis at the time of delivery was utilized to prevent infective endocarditis in all patients. No hemorrhagic or teratogenic complications were observed, and this was considered directly related to the fact that anticoagulant therapy was rendered unnecessary with the homograft valve--a distinct advantage. A more permissive policy of allowing pregnancy in young women with homograft cardiac valves is suggested by the satisfactory outcome of the pregnancies reported here.

Abortion, Induced↗
PubMed1982

Effect of small doses of aluminum-containing antacids on calcium and phosphorus metabolism.

The effect of small doses of four commercially available aluminum-containing antacids on calcium and phosphorus metabolism was investigated in adult males in 20 studies. During the use of these doses of antacids, urinary and fecal calcium increased significantly during a low calcium intake averaging 252 mg/day, and the calcium balances became distinctly more negative. There was a reversal of the normal pattern of phosphorus excretions, namely, the fecal phosphorus was high and the urinary phosphorus was low. During a normal calcium intake of 800 mg/day, these doses of antacids did not result in significant changes of the calcium excretions or balance. Despite the decrease in net intestinal absorption of calcium, the average 47Ca absorption remained unchanged, irrespective of the type and dose of antacid used. In three patients who received large therapeutic doses of antacids, 240 to 450 ml/day, the changes of calcium and phosphorus metabolism were intensified.

Adult↗