Increasing Wellness Through Physical Activity in Children With Chronic Disease and Disability.

Children with chronic medical conditions face many challenges when considering sport participation. Compared with their healthy counterparts, they are often discouraged from physical activity or sports participation because of real or perceived limitations imposed by their condition. Prescribed exercise should be based on the demands of the sport, the effect of the disease on performance, and the potential for exercise-induced acute or chronic worsening of the illness or disability. This article will focus on several examples of chronic medical conditions and the clinician's role in providing advice about sport participation.

What dentists should know about sickle cell disease.

The medical history should be a communication between the patient and the dentist. A good history will reveal a patient's medical problems,concerns, ideas, and expectations. Understanding medical conditions on a patient's medical history is of up most importance in providing the patient with the best possible standard of care. Sickle cell disease is an inherited blood disorder that affects red blood cells. Normal red blood cells contain hemoglobin A. People with sickle cell disease have red blood cells containing mostly hemoglobin S, an abnormal type of hemoglobin. These mutated sickle cells do not have the smooth motion needed for oxygenation and deoxygenation. One of the main concerns in sickle cell disease is the reversible extreme pain episodes called "sickle cell crisis."Pain episodes occur when sickle cells clog small vessels, depriving the body of adequate blood and oxygen. Treatment of the sickle cell patient should be a team approach between dentist,patient, and physician. Dental treatments should be conservative and stress free for the patient.Prevention of dental disease and infections are of the up most importance to the sickle cell patient.If your patient has sickle cell disease, know about it and talk to your patient about the disease.Maintaining excellent oral health to decrease the possibility of oral infections will ensure the best care for these patients.Key words: communication, sickle cell disease (SCD), sickle cell anemia (SCA), blood inherited disorder, sickle cell trait, crisis, African Americans, deoxygenation, hemoglobin,supporting dentist, prophylactic antibiotics, and infection.

Effects of alpha-thalassemia and sickle polymerization tendency on the urine-concentrating defect of individuals with sickle cell trait.

A defect in urine concentrating ability occurs in individuals with sickle cell trait (HbAS). This may result from intracellular polymerization of sickle hemoglobin (HbS) in erythrocytes, leading to microvascular occlusion, in the vasa recta of the renal medulla. To test the hypothesis that the severity of the concentrating defect is related to the percentage of sickle hemoglobin present in erythrocytes, urinary concentrating ability was examined after overnight water deprivation, and intranasal desmopressin acetate (dDAVP) in 27 individuals with HbAS. The HbAS individuals were separated into those who had a normal alpha-globin genotype (alpha alpha/alpha alpha), and those who were either heterozygous (-alpha/alpha alpha) or homozygous (-alpha/-alpha) for gene-deletion alpha-thalassemia, because alpha-thalassemia modulates the HbS concentration in HbAS. The urinary concentrating ability was less in the alpha alpha/alpha alpha genotype than in the -alpha/alpha alpha or -alpha/-alpha genotypes (P less than 0.05). After dDAVP, the urine osmolality was greater in patients with the -alpha/-alpha genotype than with the -alpha/alpha alpha genotype (882 +/- 37 vs. 672 +/- 38 mOsm/kg H2O) (P less than 0.05); patients with the -alpha/alpha alpha genotype had greater concentrating ability than individuals with a normal alpha-globin gene arrangement. There was an inverse linear correlation between urinary osmolality after dDAVP and the percentage HbS in all patients studied (r = -0.654; P less than 0.05). A linear correlation also existed for urine concentrating ability and the calculated polymerization tendencies for an oxygen saturation of 0.4 and O (r = -0.62 and 0.69, respectively). We conclude that the severity of hyposthenuria in HbAS is heterogeneous. It is determined by the amount of HbS polymer, that in turn is dependent upon the percentage HbS, which is itself related to the alpha-globin genotype.

Sports haematology.

While the crucial role of haemoglobin in aerobic exercise has been well accepted, there is still a great deal of controversy about the optimal haematological parameters in the athletic population. The initial part of this review will examine the question of anaemia in athletes. The most common finding in athletes is a dilutional pseudoanaemia that is caused by a plasma volume expansion, rather than an actual blood loss. It is not a pathological state and normalises with training cessation in 3 to 5 days. This entity should be distinguished from conditions associated with lowered blood counts, such as intravascular haemolysis or iron deficiency anaemia. The evaluation of true anaemia states in the athlete must take into account not only blood losses secondary to exercise, such as foot strike haemolysis or iron losses through sweat, but non-athletic causes as well. Depending on the age and sex of the athlete, consideration must be given to evaluation of the gastrointestinal or genitourinary systems for blood loss. Finally, a comprehensive nutritional history must be taken, as athletes, especially women, are frequently not consuming adequate dietary iron. The second section of the paper will deal with the very contentious issue of sickle cell trait. While there have been studies demonstrating an increased risk of sudden death in people with sickle cell trait, it is still quite rare and should not be used as a restriction to activity. Further, studies have demonstrated that patients with sickle cell trait have an exercise capacity that is probably normal or near normal. However, in the cases of sudden death, it has been secondary to rhabdomyolysis occurring among sickle cell trait athletes performing at intense exertion under hot conditions, soon after arriving at altitude. The recommendations are that athletes with sickle cell trait adhere to compliance with the general guidelines for fluid replacement and acclimatisation to hot conditions and altitude. The final section of the paper examines the issue of haematological manipulation for the purposes of ergogenic improvement. Although experiments with blood doping revealed improvements in running time to exhaustion and maximal oxygen uptake, the introduction of recombinant erythropoietin has rendered blood doping little more than a historical footnote. However, the improvements in performance are not without risk, and the use of exogenous erythropoietin has the potential for increased viscosity of the blood and thrombosis with potentially fatal results. Until a definitive test is developed for detection of exogenous erythropoietin, it will continue to be a part of elite athletics.