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Biomedical subjects

H Spencer

Publications and source records attributed to H Spencer.

At least 91 records · Page 5Linked to original sources
PubMed1981

Studies of fluoride metabolism in man. A review and report of original data.

The dietary intake of fluoride and the fluoride excretions in urine and stool were determined under controlled conditions in man. Fluoride balance studies have shown that the urinary fluoride corresponds to 50--60% of the intake, the fecal fluoride was very low, corresponding to 6% of the intake, and approximately 1 mg fluoride was retained per day during an average fluoride intake of 4.3 mg/day. The fluoride intake depended on the amount of fluoridated water consumed. The dietary fluoride content ranged from 1.2 to 1.5 mg/day. During the intake of supplemental fluoride the fluoride excretions increased but the ratio of the urinary/fecal fluoride was similar. Added fluoride is well retained. Following its discontinuation, very small amounts of the retained fluoride are excreted for several days. Inorganic elements, such as calcium, phosphorus, and magnesium, which have been shown to decrease the intestinal absorption of fluoride in animals were ineffective in man, while aluminum, given as aluminum-containing antacids, markedly decreased the intestinal absorption of fluoride and thereby decreased the retention of fluoride.

Adult↗
PubMed1981

Zinc and mineral content of weight reducing diets.

The zinc content of four commonly used weight reduction diets and of three constant diets used for weight reduction in a Metabolic Research Unit was determined by atomic absorption spectroscopy. The diets were also analyzed for other elements, namely, for nitrogen, calcium, phosphorus, magnesium, and iron. The four commonly used weight reduction diets and two of the metabolic diets contained approximately 1000 cal, while one metabolic diet contained 600 cal. The zinc content of the diets correlated with the type but not with the amount of protein used because proteins of high biological value may have a low zinc content. There was no correlation between the zinc and calorie content of the diets. Although the protein content of two equicaloric diets was normal and similar, the zinc content differed by a factor of 2. Conversely, when the dietary protein was increased the dietary zinc content remained low, half of that of the RDA. Even when the diet contained only 600 cal the zinc intake was still approximately 75% of the RDA. The phosphorus and magnesium content correlated with the dietary protein. These studies have shown that the adequacy of the zinc and iron content of weight reduction diets depends on the type of protein used, however, there is no apparent correlation between the zinc and iron content of individual protein-containing foods.

Calcium, Dietary↗
PubMed1981

Subacute fluoroacetate poisoning.

Fluoroacetic acid and some other monofluoro-compounds are among the most poisonous substances known. In man symptoms of poisoning begin after a latent period of one-half to several hours and death follows rapidly. Convulsions and arrhythmia are common terminal signs. No specific changes have been found at postmortem. It is suggested, but unproven, that sudden death of the patient whom this case report concerns was due to subacute fluoroacetate poisoning.

Adult↗
PubMed1981

Prosthetic valve infections.

Over a 10-year period, 25 patients were treated for prosthetic valve infections: 13 infections were of early onset (within 2 months of valve insertion) and 12 of late onset. Of the latter group 11 patients survived, 6 without reoperation. By contrast, 6 of the 13 with early infections died, 5 of them being among the group of 9 patients who did not undergo reoperation. Vegetations were found on most valves at autopsy or reoperation; they are a major threat to these patients. The authors believe that the mortality for early prosthetic valve infections can be reduced only by earlier prosthetic valve removal and replacement.

Anti-Bacterial Agents↗
PubMed1980

Non-invasive bronchial epithelial papillary tumors.

Nineteen papillary, non-invasive tumors arising from the bronchial epithelium but excluding carcinoid tumors are reviewed. Eight were solitary papillomas of which three were covered with a mixture of epithelial types. Seven were benign but one had a focus of carcinoma in situ. A similar change was seen in bronchial epithelium adjacent to a papilloma. Two cases of recurrent papillomas were seen and in one, carcinomatous changes eventually occurred. Two combined benign brochial cystadenomas with papillomas are described. One transitional celled papillary carcinoma in situ and five other papillary carcinomas in situ are described. One bronchial papilloma covered with dysplastic epithelium was considered an intermediate stage in the development of carcinoma in situ. Two papillary tumors may have arisen from peripheral bronchi or brochioles. Their lining cells resembled Clara cells, they grew by local expansion, and there was an absence of malignant features. The differential characteristics of two secondary carcinomatous polypoidal tumors are described.

Adult↗
PubMed1980

Zinc65 absorption in patients with carcinoma of the prostate.

The intestinal absorption of 65 Zn was determined in patients with carcinoma of the prostate prior to treatment and during estrogen therapy. Following an oral tracer dose of 65 ZnCl2, plasma levels and urinary and fecal excretions of 65 Zn were determined. The absorption of 65 Zn was low in six of eight patients, particularly in three patients who had extensive metastatic bone involvement. During estrogen therapy the absorption of 65 Zn increased markedly in these patients, and this increase correlated with the clinical remission of the neoplastic process. In one patient who did not respond to estrogen therapy, 65 Zn absorption was normal prior to treatment and did not increase during estrogen therapy. In patients free of neoplasia estrogen administration did not increase 65 Zn absorption, and even decreased it. These results indicate that the intestinal absorption of 65 Zn is decreased during the active phase of carcinoma of the prostate and improves during clinical remission induced by estrogen therapy.

Aged↗
PubMed1980

Effect of aluminum hydroxide on fluoride metabolism.

Aluminum inhibits intestinal absorption of fluoride in animals but little information is available about man. To determine whether and to what extent aluminum affects fluoride absorption in man, effects of aluminum hydroxide on fluoride metabolism were studied under controlled dietary conditions. Relatively small amounts of aluminum hydroxide were used (30 ml three times daily, containing a total of 1.8 gm aluminum, were given for several weeks). Fluoride balances were determined in control studies and during the intake of aluminum hydroxide. The fluoride intake was the fluoride content of the diet and the drinking water. Two studies were also carried out on a high-fluoride intake. The use of aluminum hydroxide was associated with an increase in fecal fluoride excretion and a decrease in net absorption of fluoride regardless of the intake fluoride, calcium, phosphorus, or magnesium. Urinary fluoride decreased during aluminum hydroxide ingestion. Our studies show that relatively small amounts of aluminum hydroxide inhibit intestinal absorption of fluoride in man.

Aged↗
PubMed1980

Effect of calcium, phosphorus, magnesium, and aluminum on fluoride metabolism in man.

The studies of the interaction of fluoride with minerals in man have shown that: 1. in contrast to observations made in animals, the high intake of calcium, phosphorus, and magnesium in amounts that can be used in humans did not inhibit the intestinal absorption of fluoride in man; 2. the lack of effect of added calcium, given in divided doses, on the intestinal absorption of fluoride has relevance for the use of a high calcium intake during fluoride therapy for osteoporosis; 3. aluminum as the hydroxide, commonly used as an antacid in clinical medicine, significantly decreases the intestinal absorption of fluoride. This inhibitory effect, in conjunction with the known effects of aluminum-containing antacids in causing calcium loss as a consequence of phosphorus depletion, may contribute to the development of skeletal demineralization.

Adult↗
PubMed1980

Fluoride metabolism in patients with chronic renal failure.

Studies of fluoride metabolism were carried out in patients with chronic renal failure by determining fluoride balances for several weeks. The fluoride intake was due to the analyzed fluoride content of the diet and of the drinking water. The effect of aluminum hydroxide on fluoride metabolism was investigated because this antacid is commonly used therapeutically for these patients. Studies have shown that urinary fluoride excretion in patients with chronic renal failure was significantly lower than that in patients with normal renal function, resulting in a signicantly higher retention of fluoride. Although the fecal fluoride excretion in patients with chronic renal failure was slightly but significantly increased, this change did not compensate for the decrease of the urinary fluoride excretion. The intake of aluminum hydroxide resulted in a significant increase of fecal fluoride excretion and in a significant decrease of net absorption and retention of fluoride in patients with chronic renal failure.

Aged↗