The combination of platelet-derived growth factor-BB and insulin-like growth factor-I stimulates bone repair in adult Yucatan miniature pigs

The combination of insulin-like growth factor-I and platelet-derived growth factor-BB has previously been shown to stimulate healing of soft tissue wounds and the formation of bone and ligament around teeth. The purpose of the present study was to evaluate the effects of platelet-derived growth factor-BB and insulin-like growth factor-I individually and in combination on the healing of osseous wounds. Four standardized cortical wounds were created in each tibia of 11 adult Yucatan miniature pigs. The wounds in one tibia per animal were treated with either purified recombinant human insulin-like growth factor-I, platelet-derived growth factor-BB, or both in a methylcellulose gel. The wounds in each contralateral tibia received placebo gel alone. Coded serial sections of each wound were evaluated by computer-aided histomorphometry 21 days after surgery. The area and perimeter of the newly formed mineralized callus, the thickness of the total callus, and the percentage of mineralized tissue within the callus were significantly increased compared with the values of matched controls only in wounds treated with a combination of insulin-like growth factor-I and platelet-derived growth factor-BB. No significant differences in the measured parameters of callus formation were found in wounds treated with either insulin-like growth factor-I or platelet-derived growth factor-BB alone. Cartilage was present only in sites treated with insulin-like growth factor-I alone. These results suggest that the combination of platelet-derived growth factor-BB and insulin-like growth factor-I stimulates bone formation in wounds in long bones of adult animals and that these growth factors act via different pathways during the repair process.     

Amputation in elderly and high-risk vascular patients

Fifty-eight patients underwent lower limb amputation for arterial disease over a 30-month period. Mean age of the patients was 72 years. Cardiopulmonary and metabolic risk factors were present in the majority of the patients. Postoperative one-year and three-year mortality rates were 24, 40, and 76%, respectively. Contralateral amputation was required in one-third of the patients after a mean period of eight months. Only younger and healthier patients returned to a meaningful social life after appropriate prosthetic fitting. In view of the high mortality and morbidity rates, above-knee amputation seems a better choice than below-knee amputation in these elderly and high-risk patients.     

Importance of Dietary Fiber in Childhood

Dietary fiber has important health benefits in childhood, especially in promoting normal laxation. Currently, children consume amounts of dietary fiber that appear to be inadequate for optimal health promotion and disease prevention. It is prudent to recommend that children older than 2 years of age increase dietary fiber intake to an amount equal to or greater than their age + 5 g/day. According to the “age + 5” rule dietary fiber intake would increase from 8 g/day at age 3 years to 25 g/day by age 20 years. After age 20, dietary fiber levels of 25 to 35 g/day are recommended. Dietary fiber intake should be increased gradually in childhood by increasing consumption of a variety of fruits, vegetables, legumes, cereals, and other whole-grain products. Although very high fiber intake in childhood could have adverse effects, the potential health benefits of a moderate increase in dietary fiber substantially outweigh the possible risks, especially in highly industrialized countries such as the United States. A safe range of dietary fiber intake for children may be between age + 5 and age + 10 g/day. This range is considered safe even for children and adolescents with marginal intakes of some vitamins and minerals; should provide enough dietary fiber for normal laxation; and may provide enough added dietary fiber to help prevent chronic diseases.J Am Diet Assoc. 1995; 1140-1146, 1149.     

Influence of the mother-child relationship on the development of the Type A Behavior Pattern

Investigation of the Type A Behavior Pattern (TABP) of pre-school children was conducted to determine the influence of the mother-child relationship on the development of TABP. The incidence of TABP was 44.2% (51.7% in boys and 38.7% in girls). The TABP tendency of the boys decreased as the manifest dissension or conflict in the family grew, in marked contrast with the tendency seen in girls, suggesting that conflict in the family can either weaken or reinforce TABP.     

Salt sensitivity and systemic hypertension in the elderly

Aging in industrialized societies is accompanied by increases in the incidence and prevalence of hypertension, with a disproportionately greater increase occurring among aging blacks than among aging whites. This geriatric hypertension is generally of a salt-sensitive nature with a disproportionate frequency of isolated systolic hypertension. Although salt-taste acuity declines with age, salt sensitivity among the elderly does not appear to result from a compensatory increase in salt intake. Rather, age-related increases in salt sensitivity result, in part, from a reduced ability to appropriately excrete a salt load, which is due to a decline in renal function and to a reduced generation of natriuretic substances such as prostagiandin E₂ and dopamine. Age-associated declines in the activity of membrane sodium/potassium-adenosine triphosphatase (Na/K-ATPase) may also contribute to geriatric hypertension because this results in increased intracellular sodium that may cause reduced sodium-calcium exchange and thereby increase intracellular calcium and vascular resistance. Reductions in cellular calcium efflux due to reduced calcium-ATPase activity may similarly cause an increase in intracellular calcium and vascular resistance. Increasing dietary calcium intake may represent an effective nonpharmacologic treatment for some salt-sensitive persons because it appears to reduce intracellular calcium by (1) suppressing parathyroid hormone-mediated calcium influx, (2) increasing Na/K-ATPase activity, and (3) reducing intravascular volume due to calcium-induced natriuresis.