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Biomedical subjects

J Busby

Publications and source records attributed to J Busby.

17 recordsLinked to original sources
PubMed1997

Cloning and characterization of a calcium-sensing receptor from the hypercalcemic New Zealand white rabbit reveals unaltered responsiveness to extracellular calcium.

The extracellular Ca2+ (Ca(0)2+)-sensing receptor (CaR) recently cloned from mammalian parathyroid, kidney, brain, and thyroid plays a central role in maintaining near constancy of Ca(0)2+. We previously showed that the hypercalcemia normally present in New Zealand white rabbits is associated with an elevated set point for Ca(02+)-regulated PTH release (the level of Ca(0)2+ half-maximally inhibiting hormonal secretion). This observation suggested an alteration in the Ca(02+)-sensing mechanism in the rabbit parathyroid, a possibility we have now pursued by isolating and characterizing the rabbit homolog of the CaR. The cloned rabbit kidney CaR (RabCaR) shares a high degree of overall homology (> 90% amino acid identity) with the bovine, human, and rat CaRs, although it differs slightly in several regions of the extracellular domain potentially involved in binding ligands. By Northern analysis and/or immunohistochemistry, a similar or identical receptor is also expressed in parathyroid, thyroid C cells, small and large intestine, and in the thick ascending limb and collecting ducts of the kidney. When expressed transiently in HEK293 cells and assayed functionally through CaR agonist-evoked increases in Ca(i)2+, the rabbit CaR shows apparent affinities for Ca(0)2+, Mg(0)2+, and Gd(0)3+ that are indistinguishable from those observed in studies carried out concomitantly using the human CaR. Therefore, at least as assessed by its ability to increase Ca(i)2+ when expressed in HEK293 cells, the intrinsic functional properties of the rabbit CaR cannot explain the hypercalcemia observed in vivo in the New Zealand white rabbit.

Amino Acid Sequence↗
PubMed1991

Texas blood.

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Acquired Immunodeficiency Syndrome↗
PubMed1985

Immune function, autoimmunity, and selective immunoprophylaxis in the aged.

Many changes occur in the immune system with age. The involution of the thymus plays a major role in immune senescence. Related to this event are the altered ratio of helper to suppressor T-lymphocyte subsets, decrease in immune response by both cell-mediated and humoral branches of the immune system, and increase in autoimmune activity. The clinical implications of these changes are the elderly person's increased susceptibility to infections such as pneumococcal pneumonia, influenza A, and tetanus as well as increased autoimmune activity, reflected by pernicious anemia. Other changes may be increased susceptibility to neoplasms and perhaps acceleration of the aging process. A high index of suspicion should be present for the diagnosis of pernicious anemia in the elderly population. Knowledge of the many autoantibodies that might be present without illness is important when evaluating for disease processes. The relationship of the senescent immune system to the aging process is still unknown. Investigations of this matter, as well as of the function of immune system components and their relationship to disease processes, are continuing. Most methods proposed for enhancing the immune system are still experimental. However, immunizations have been proved to be an effective means of reducing morbidity and mortality from certain infectious diseases in the elderly. Therefore, it is strongly recommended that all elderly persons who are at risk for pneumococcal pneumonia, influenza, and tetanus receive the proper immunizations.

Aged↗
PubMed1985

Exercise, high-density lipoprotein-cholesterol, and cardiorespiratory function in climacteric women.

Fifty healthy women between the ages of 40 and 65 participated in a 12-week program of exercise, discussion sessions, or both. Levels of serum cholesterol, triglycerides, total high-density lipoprotein (HDL), HDL-cholesterol, and HDL-2b were monitored at baseline and at six and 12 weeks. Cardiorespiratory function was assessed at baseline and 12 weeks. Women participating in the exercise groups had smaller increases in serum cholesterol (P less than .05) and greater increases in maximal oxygen consumption, time spent on a treadmill, and time required to attain 90% of maximal oxygen consumption (P less than .01) than the nonexercising women. No statistically significant differences were observed in levels of serum triglycerides, total HDL, or HDL-cholesterol fractions between nonexercising and exercising groups at either six or 12 weeks.

Adult↗
PubMedDate not supplied

A longitudinal study of osteoarthritis of the hand: the effect of age.

Osteoarthritis is the most ubiquitous rheumatic disease worldwide. Although its prevalence in various populations has been well documented, few studies have evaluated the longitudinal radiographic progression of the disease, especially as it is expressed in the interphalangeal joints of the hand. In this longitudinal study, left hand-wrist X-rays of 386 white male participants of the Baltimore Longitudinal Study of Aging followed for at least 5 years with two or more visits were examined for prevalence and progression of osteoarthritis of the distal and proximal interphalangeal joints of the hand. As other studies have shown, we found that the prevalence of osteoarthritis in both distal and proximal interphalangeal joints becomes progressively higher as the age of the subjects increases. Using the life table method of analysis we studied the progression of osteoarthritis as defined by the following criteria: (1) an increase in the severity of radiographic changes of the joints previously affected and (2) an increase in the number of new joints affected. The results indicated that osteoarthritis in both the distal and proximal interphalangeal joints progresses at a faster rate in the older population than in individuals less than 60 years of age. Furthermore, osteoarthritis in the interphalangeal joints progresses at the same rate whether the starting point was a Kellgren grade of 0 (no disease) or 1 (doubtful). We therefore conclude that grade 1 is an intermediate step in the inexorable progression of osteoarthritis of the interphalangeal joints and not synonymous with grade 0, as it has been customarily interpreted.

Adolescent↗