Biomedical subjects

K M Ryder

Publications and source records attributed to K M Ryder.

3 recordsLinked to original sources

PubMed2003

Appendicular fractures: a significant problem among institutionalized adults with developmental disabilities.

A high incidence of nontraumatic fracture in adults with developmental disabilities living in a state-run facility was described. Risk factors for fracture, including bone mineral density (BMD), were investigated to determine whether people at highest risk for fracture could be prospectively identified. There was a 7.3% incidence of fracture among 391 adults. Risk factors were examined for 23 residents with fracture and 23 age-, race-, and gender-matched controls. There was a trend for antiepileptic medication usage to be associated with fractures. Estimated BMD by heel ultrasound did not predict fracture; however, values were much lower than those for the general population. Fractures and low BMD are significant problems among institutionalized adults with severe developmental disabilities. Further studies to identify therapies to prevent fractures are warranted.

Adolescent↗

PubMed1999

Epidemiology and significance of atrial fibrillation.

Atrial fibrillation (AF) is the most common sustained arrhythmia, affecting an estimated 2.2 million adults in the United States. The median age of people with AF is 75, and it affects 8.8% of the US population > 80 years of age. Prevalence data from other countries are presented. Direct comparisons are limited by study design, but rough comparisons suggest that the prevalence of AF in Europe is similar to the prevalence in the United States, whereas the prevalence in Asia may be lower. The limited comparative data underscore our lack of understanding of AF risk factors and complications in racial subgroups and in developing countries. AF increases stroke risk 5-fold. The clinical features that predict higher risk of stroke in AF are prior stroke, hypertension, advancing age, diabetes, and congestive heart failure. Predicting which patients with atrial fibrillation are at the highest risk of stroke remains a challenge. Echocardiographic findings have been investigated to assist in the risk stratification of patients with AF. Despite evidence from clinical trials that anticoagulation with warfarin reduces stroke incidence and even mortality, anticoagulation remains underutilized, especially in the elderly. Improvement in the rate of anticoagulation in patients with AF at risk of stroke can be expected to decrease the complications and mortality of AF.

Adult↗

PubMed1995

Hippocampal GABA transporter function in temporal-lobe epilepsy.

Electrophysiological studies of human temporal-lobe epilepsy suggest that a loss of hippocampal GABA-mediated inhibition may underlie the neuronal hyperexcitability. However, GABA (gamma-aminobutyric acid)-containing cells are preserved and GABA receptors are maintained in the surviving hippocampal neurons. Diminished GABA release may therefore mediate the loss of inhibition. Here we show that, in the human brain, potassium-stimulated release of GABA was increased, and glutamate-induced, calcium-independent release of GABA was markedly decreased, in epileptogenic hippocampi, in contrast with contralateral, non-epileptogenic hippocampi. The glutamate-induced GABA release in vivo was transporter-mediated in rats. Furthermore, in amygdala-kindled rats, a model for human epilepsy, a decrease in glutamate-induced GABA release was associated with a 48% decrease in the number of GABA transporters. These data suggest that temporal-lobe epilepsy is characterized in part by a loss of glutamate-stimulated GABA release that is secondary to a reduction in the number of GABA transporters.

Amygdala↗