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Biomedical subjects

R R Recker

Publications and source records attributed to R R Recker.

160 records · Page 9Linked to original sources
PubMed1975

Calcium absorption as a function of calcium intake.

The relationships between the amount of calcium absorbed and the quantity ingested was evaluated in 180 adult humans. Absorption was measured from the concentration ratio of concurrently administered oral and intravenous calcium isotopes. Intake ranged from 0.163 to 7.48 Gm. Ca per day. In 14 subjects, intakes were artificially elevated for purposes of this study. All others were studied at their usual intake levels. Absorption (Ca Abs) was found to follow a curvillnear relationship with intake (Ca-D), and was characterized by the following equation: Ca Abs equals 0.1541 - Ca-D plus 0.3127[exp(-1.0539 - Ca-D)] - Ca-D. The exponential term of this equation provided the major component of total absorption at intakes below 0.8 Gm. per day, but fell to negligible values when intake reached 2 to 3 Gm. per day, above which absorption was characterized by a simple linear function of intake. We found that there was no detectable upper limit to absorption capacity, which, at the 7.48 Gm. intake level, averaged more than 1.0 Gm per day. The observed mathematical description is consistent with the generally recognized inverse relationship between absorption efficiency and intake. At the same time it indicates that a component of absorption is independent of control mechanisms and is related solely to intake. A more general form of the foregoing equation, suggesting provision for other physiological variables such as growth hormone and cortisol, is proposed and discussed.

Acromegaly↗
PubMedDate not supplied

Metabolic bone disease in alcoholic cirrhosis: a comparison of the effect of vitamin D2, 25-hydroxyvitamin D, or supportive treatment.

In a study of 56 alcoholics with liver cirrhosis, 18 (32%) had decreased bone density and low levels of serum 25-hydroxyvitamin D (25-OH-D) (less than 20 ng per ml). To compare the efficacy of vitamin D2 and 25-OH-D treatment in correcting the metabolic bone disease in alcoholic cirrhosis, the 18 patients were randomized in the following manner, in groups of six patients each: Group 1, control (received no supplemental vitamin D treatment); Group 2, given vitamin D2 (50,000 IU p.o.) two to three times weekly, and Group 3, treated with 25-OH-D (20 to 50 mg p.o.) daily as required to attain normal serum 25-OH-D levels. The study period lasted 6 to 12 months (mean, 10.7 months). Initial histomorphometric study of transiliac bone biopsy with double tetracycline labeling in nine patients in whom biopsy was feasible showed only osteoporosis without evidence of osteomalacia. By the end of the study, serum 25-OH-D levels in the control group (Group 1) raised slightly while showing marked improvement in Groups 2 and 3. Bone density results remained unchanged in control patients but demonstrated a significant increase in both treatment groups. Vitamin D2 and 25-OH-D were equally effective in increasing bone density measurements. Posttreatment biopsies were performed in three patients of Group 2 and two patients of Group 3. While the histomorphometric results in Group 3 were not conclusive, in Group 2 improvement in static measures of bone remodeling was noted. Osteoporosis is the usual form of bone disease in alcoholic cirrhosis and a response to either vitamin D2 or 25-OH-D treatment is suggested.

25-Hydroxyvitamin D 2↗
PubMedDate not supplied

Aluminum does not accumulate in teenagers and adults on prolonged parenteral nutrition containing free amino acids.

Prolonged total parenteral nutrition (TPN) with solutions containing hydrolyzed casein has been associated with aluminum accumulation in patients with bone disease. We investigated the effects of free amino acids in TPN solution on plasma, urine, and bone aluminum in six patients, five of whom had symptoms of bone disease or documented demineralization. No evidence of aluminum accumulation was found. TPN with free amino acids, containing 42 micrograms aluminum per liter or less, does not lead to aluminum loading in adolescents or adults.

Adolescent↗
PubMedDate not supplied

A randomized study of the effects of a home diabetes education program.

Home health nurses provided individualized instruction in diabetes self-care within the home environment of 393 diabetic individuals. Each subject was randomly assigned to either the intervention (those receiving home teaching) or control (those not receiving home teaching) group. At 6 mo postenrollment, intervention subjects showed significantly greater self-care knowledge and skills than control subjects, although the actual differences between the two groups in terms of self-care skills were probably too small to have any practical meaning. The primary objective of the study, which was the reduction of the number of preventable diabetes-related hospitalizations (ketoacidosis, ketotic coma, nonketotic coma, insulin reaction, and diabetes out of control), was not achieved; no differences between the groups were noted after 12 mo of follow-up. Similarly, length of hospital stay, foot problems, emergency room and physician visits, and sick days were roughly equivalent in both groups during the follow-up year. These results suggest that, in the absence of concurrent changes in the health-care delivery system and strategies for influencing attitudes toward self-care, education alone is ineffective.

Diabetes Complications↗
PubMedDate not supplied

Radiogrammetry at four bone sites in normal middle-aged women. their relation to each other, to calcium metabolism and to other biological variables.

In 167 women, ages 41 +/- 3.5 years, who constituted 80 per cent of nuns of this age group in the Omaha area, body dimensions and radiogrammetric indices were determined in (1) radius; (2) femoral shaft; (3) second metacarpal. Calcium, phosphorus and nitrogen balance were measured and calcium kinetics were calculated following oral and intravenous administration of two radioisotopes of calcium. The bone indices were significantly correlated to each other. The femoral diameter was correlated to all the kinetic variables, the radial to many, and the metacarpal to a few. All bone diameters were correlated to height, but only the femoral diameter to body weight. Femoral shaft diameter increased with time after the menopause, but was not correlated to age. There was no correlation between any bone variable and dietary calcium, absorbed calcium, or calcium balance. High dietary calcium was associated with lower bone resorption. There was no correlation between any bone variable and the urinary excretion of estrogens or 17 ketosteroids or 17 hydroxycorticosteroids. Although different bones of the skleton are qualitatively and quantitatively related, in survey work the femoral shaft should be included as a skeletal marker in addition to the second metacarpal. Femoral expansion occurs in women after the menopause. In normal women, dietary calcium is unrelated to skeletal indices.

Adult↗