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Biomedical subjects

L H Beck

Publications and source records attributed to L H Beck.

At least 19 recordsLinked to original sources
PubMed2000

Screening and preventive health practices for the end-stage renal disease patient.

The population of end-stage renal disease (ESRD) patients continues to grow and to age. The nephrologist often is the sole or principal physician responsible for the total management of these patients. In this role, the nephrologist must address issues of routine health maintenance. Screening tests and preventive care should be continued to detect, prevent, or minimize comorbid conditions that could affect quality of life or survival. Effective primary and secondary prevention requires understanding the principles of screening tests and their appropriate use. Screening and counseling procedures recommended for healthy adults should be continued, although certain screening tests may appropriately be discontinued if the expected survival is 5 years or less. Secondary prevention for cardiovascular disease is particularly important in ESRD patients, in whom accelerated atherosclerosis is often the cause of morbidity and death. Aggressive counseling in smoking cessation and in management of hyperlipidemia should be undertaken, in the hopes of limiting this common comorbidity.

Colorectal Neoplasms↗
PubMed2000

The aging kidney. Defending a delicate balance of fluid and electrolytes.

The aging kidney is characterized by reduced glomerular filtration rate, loss of tubular volume, and narrowed homeostatic control of water and electrolyte balance. It is unclear whether these physiologic changes represent normal aging or subclinical disease. With aging, there is an increased risk of hyper- or hypovolemia. Sluggish control of potassium concentration also makes hyperkalemia more common, particularly when the patient is using certain drugs. Water metabolism is particularly vulnerable in older patients, resulting in a frequent tendency toward dehydration and hyperosmolality. Understanding these limitations on fluid and electrolyte homeostasis can help the clinician recognize and prevent complications when caring for older patients.

Aging↗
PubMed1999

Periodic health examination and screening tests in adults.

Whenever a patient presents for the annual health examination, clinicians must choose from a plethora of screening tests and conflicting sets of guidelines. A discussion of the underlying issues leads to practical tips on how select and when to abandon screening tests and when to treat or not treat patients with marginally positive test results.

Adult↗
PubMed1999

Endothelial cells modulate the proliferation of mural cell precursors via platelet-derived growth factor-BB and heterotypic cell contact.

Embryological data suggest that endothelial cells (ECs) direct the recruitment and differentiation of mural cell precursors. We have developed in vitro coculture systems to model some of these events and have shown that ECs direct the migration of undifferentiated mesenchymal cells (10T1/2 cells) and induce their differentiation toward a smooth muscle cell/pericyte lineage. The present study was undertaken to investigate cell proliferation in these cocultures. ECs and 10T1/2 cells were cocultured in an underagarose assay in the absence of contact. There was a 2-fold increase in bromodeoxyuridine labeling of 10T1/2 cells in response to ECs, which was completely inhibited by the inclusion of neutralizing antiserum against platelet-derived growth factor (PDGF)-B. Antisera against PDGF-A, basic fibroblast growth factor, or transforming growth factor (TGF)-beta had no effect on EC-stimulated 10T1/2 cell proliferation. EC proliferation was not influenced by coculture with 10T1/2 cells in the absence of contact. The cells were then cocultured so that contact was permitted. Double labeling and fluorescence-activated cell sorter analysis revealed that ECs and 10T1/2 cells were growth-inhibited by 43% and 47%, respectively. Conditioned media from contacting EC-10T1/2 cell cocultures inhibited the growth of both cell types by 61% and 48%, respectively. Although we have previously shown a role for TGF-beta in coculture-induced mural cell differentiation, growth inhibition resulting from contacting cocultures or conditioned media was not suppressed by the presence of neutralizing antiserum against TGF-beta. Furthermore, the decreased proliferation of 10T1/2 cells in the direct cocultures could not be attributed to downregulation of the PDGF-B in ECs or the PDGF receptor-beta in the 10T1/2 cells. Our data suggest that modulation of proliferation occurs during EC recruitment of mesenchymal cells and that heterotypic cell-cell contact and soluble factors play a role in growth control during vessel assembly.

Animals↗
PubMed1998

Changes in renal function with aging.

Despite losing 20%-25% of their original kidney volume, older individuals maintain body fluid hemostasis under most circumstances; however, their ability to withstand environmental, disease-related, or iatrogenic stresses becomes progressively narrowed. Glomerular filtration rates fall with each decade, accompanied by limitations on sodium conservation, potassium ion secretion, and acid excretion. Medications used by older patients are a common cause of hyperkalemia through a number of pathophysiologic mechanisms. In addition, water homeostasis frequently fails due to defects in thirst, urinary concentrating ability, and free water excretion, resulting in hypernatremia or hyponatremia in many sick older patients.

Adult↗
PubMed1990

Perioperative renal, fluid, and electrolyte management.

Normal physiologic changes of aging increase the likelihood of renal-electrolyte disorders in the elderly surgical patient. The most important of these changes are a decrease in the GFR, decreased urinary concentrating ability, and narrowed limits for the excretion of water, sodium, potassium, and acid. Because of the decrease in GFR, the elderly surgical patient is at increased risk for virtually every cause of acute renal failure, an outcome associated with a mortality of greater than 50%. Certain types of surgery, especially cardiac, aortic, and biliary tract operations, are associated with a higher risk of acute renal failure than are others. The most important principles of prevention in the elderly surgical patient are to maintain normal intravascular volume and avoid hypovolemia. Meticulous attention must be paid to salt and water balance and to drug dosing. Should perioperative renal insufficiency occur, evaluation and management in the elderly patient are similar to usual practices in a younger individual.

Acute Kidney Injury↗
PubMed1988

Maintaining health with renal disease or dysfunction.

A decline in renal function, similar to mild chronic renal insufficiency, normally occurs in the elderly concomitantly with various anatomic and histologic changes in the kidney. These morphologic and physiologic changes result in diminished ability to respond to body fluid or solute stresses. Superimposition of chronic renal insufficiency upon these age-related physiologic changes can accelerate renal functional decline. However, with proper management, most elderly patients with renal disease can remain highly functional.

Aged↗