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Biomedical subjects

H Spencer

Publications and source records attributed to H Spencer.

At least 55 records · Page 3Linked to original sources

Chronic alcoholism. Frequently overlooked cause of osteoporosis in men.

A radiographic survey was made of 96 fully ambulatory male patients who were admitted to a rehabilitation center for patients with chronic alcoholism in an attempt to estimate the incidence of skeletal demineralization in these patients. The age of the patients ranged from 24 to 62 years. Forty-five of the 96 male patients, or 47 percent of this group, showed radiographic evidence of extensive bone loss. Fourteen or 31 percent of these 45 patients with bone loss were relatively young (age 31 to 45 years), and half of this group of 14 patients were less than 40 years old. The majority of the 45 patients with radiographic evidence of osteoporosis, namely, 31 patients or 69 percent, were older and ranged in age from 46 to 62 years. One third of the patients in this group were less than 50 years old. The radiographic survey of the 96 patients indicates the high incidence of extensive bone loss, most likely osteoporosis, in relatively young and middle-aged ambulatory men with chronic alcoholism. In 12 additional patients with chronic alcoholism who were observed in the Metabolic Research Ward, and who were not part of this survey, bone biopsy specimens confirmed the radiographic diagnosis of osteoporosis.

Adult↗

The effect of phosphorus on endogenous fecal calcium excretion in man.

The effect of phosphorus on the endogenous fecal calcium excretion was investigated in man by administering tracer doses of 47Ca intravenously in control studies and during phosphorus supplementation. The phosphorus intake was approximately 800 mg/day in control studies and 2000 mg during phosphorus supplementation of the constant diet. The studies were carried out during different calcium intake levels of approximately 200, 800, 1300, 2000, and 2600 mg/day. Following the dose of 47CaCl2, the values of the plasma levels, urinary, and fecal excretions of 47Ca were used to calculate the endogenous fecal calcium. None of these values differed significantly during phosphorus supplementation from those in corresponding control studies, irrespective of the calcium intake. During addition of phosphorus to the different calcium intakes, a consistent finding was a significant decrease of the urinary calcium and a slight, but not significant increase of the fecal calcium except during the 800 mg calcium intake.

Aged↗

Metabolic chromium balances in men.

A chromium (Cr) balance study was conducted on a metabolic unit for 12 days in two normal males, ages 62 and 66, ingesting a nutritionally adequate, constant diet. Complete urine and stool collections were obtained daily. The diet, stool, and urine were analyzed for chromium by Zeeman atomic absorption spectrometry. On dietary Cr intakes of 36.9 and 36.7 micrograms/day, only a small fraction of the ingested Cr, 0.9 microgram and 0.5 microgram/day, was absorbed. Most of the dietary Cr, 36.0 micrograms and 36.2 micrograms/day, was excreted in the stool. Urinary Cr was constant from day to day with a mean of 0.30 microgram/day +/- 0.03 SD and 0.28 microgram/day +/- 0.05 SD. The Cr balances (apparent net retention) were positive, 0.6 and 0.2 microgram/day, indicating equilibrium. The average apparent net absorption of Cr for the two subjects was 1.8%.

Chromium↗

Sclerosing haemangiomas of the lung.

A series of 29 pulmonary sclerosing haemangiomas is analysed. Included is one case with multiple tumours and another with metastatic growth in a hilar lymph node. Histochemical and electron microscopic studies show that type 2 pneumocytes are an important constituent cell type though bronchial structures, tumorlets and angiomas also occur within these tumours. They are considered to be pulmonary hamartomas formed from distal lung structures. They are of slow growth and have been confused in the past with pulmonary histiocytomas and plasma cell granulomas.

Adult↗

The calcium requirement and factors causing calcium loss.

Studies carried out under strictly controlled conditions during different calcium intakes in adult males have shown that the average calcium balance was only slightly positive (+22 mg/day) during a calcium intake of 800 mg/day, the recommended dietary calcium intake, not taking into consideration dermal losses of calcium. During this calcium intake, the calcium balances were negative in 34% of the subjects studied. Increasing the calcium intake to 1200 mg/day resulted in a significant increase of the calcium balance; further increases to different intake levels up to 2300 mg/day did not improve the calcium balance further. Increasing the phosphorus intake up to 2000 mg/day as well as increasing the protein intake from 1 g/kg body weight to 2 g/kg, given as meat, did not have an adverse effect on calcium metabolism. A variety of drugs, notably aluminum-containing antacids, induced calcium loss. Increasing the calcium intake more than 10-fold from 200 to 2500 mg/day did not lower the blood pressure in a large number of normotensive patients and in a small number of hypertensive patients studied.

Antacids↗

Osteoporosis: calcium, fluoride, and aluminum interactions.

A gradual loss of bone occurs with age. There are indications in the literature that not only calcium but also fluoride may play an important role in maintaining the bone mass. In view of the high incidence of osteoporosis and its complications, and in view of the fact that fluoride is beneficial for the treatment of osteoporosis, studies have been carried out in this research unit to determine the retention and excretion of fluoride both during a normal dietary intake of fluoride and during fluoride supplementation. Another problem to be examined was to delineate whether certain substances interfere with the intestinal absorption of fluoride and of calcium. One such substance is aluminum contained in commonly used antacids. The use of small amounts of aluminum-containing antacids increased fecal fluoride significantly, thereby decreasing the intestinal absorption of fluoride. In addition, the small doses of aluminum-containing antacids also affected the metabolism of calcium and phosphorus, the primary effect being complexation of phosphorus in the intestine leading to phosphorus depletion. This change in phosphorus metabolism was associated with an increase of the urinary and fecal calcium excretion resulting in a negative calcium balance. The dual effect of aluminum, namely in causing calcium loss and inhibition of the intestinal absorption of fluoride, can result in adverse effects on bone which may contribute to bone loss.

Aluminum↗

Ethanol and fetal nutrition: effect of chronic ethanol exposure on rat placental growth and membrane-associated folic acid receptor binding activity.

Rat placental composition and specific folate receptor activity were measured at 20 days gestation in dams exposed to chronic high doses of ethanol (6%, vol/vol) throughout gestation and in isocalorically pair-fed controls. Ethanol-exposed fetuses were smaller (ethanol = 3.28 +/- 0.08 vs. control = 4.01 +/- 0.10 g, p less than 0.001), but their placentae were larger (experimental = 0.534 +/- 0.02 vs. control = 0.399 +/- 0.01 g, p less than 0.001). The increased weight appears to be secondary to hyperplasia as total DNA was increased while the wet/dry, RNA/DNA, and protein/DNA ratios were not different. Despite larger placentae, specific folate receptor activity was significantly reduced in the ethanol-exposed tissue, whether expressed relative to membrane protein, placental weight, or total placental binding. These results confirm that ethanol exposure is placentotoxic and suggest an additional mechanism by which ethanol may lead to intrauterine growth retardation; namely, decreased folate receptor activity.

Animals↗

Effect of intrauterine ethanol exposure on fetal lung growth.

Lung weight, DNA, RNA, protein, and total body weight were analyzed in fetuses from 14 pregnant Sprague-Dawley rats fed a nutritionally complete liquid diet containing v/v 6% ethanol (ethanol group). Each ethanol rat was matched with an isocalorically pair-fed animal (control group) who received the same liquid diet with carbohydrate substituted for ethanol. The rats were killed on day 20 of gestation. The mean maternal blood ethanol concentration at 0700 h on day 20 was 170 +/- 22 (SE) mg/dl. Compared to controls, ethanol fetuses had reduced body weight (21%), lung dry weight (39%), lung wet weight/body weight ratio (10%), DNA (21%), RNA (25%), protein (28%), and protein/DNA ratio (8%) (p less than 0.05). The results indicate that prenatal ethanol exposure inhibits cellular growth in the fetal lung, resulting in hypoplastic lungs which have fewer and smaller cells. The effect on the lung appears to be greater than on the body as a whole. These hypoplastic lungs may be predisposed to the development of pulmonary disease and may explain observations of more frequent and severe lower respiratory infections in children with prenatal ethanol exposure.

Animals↗