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Biomedical subjects

J E Riggs

Publications and source records attributed to J E Riggs.

At least 37 records · Page 2Linked to original sources
PubMed1999

Focal rhabdomyolysis and brachial plexopathy: an association with heroin and chronic ethanol use.

A 22-year-old man presented with acute swelling of the left neck and associated weakness of the left arm upon awakening after having snorted heroin. He had consumed large amounts of ethanol regularly for 7 years. Serum creatine kinase was greater than 19,000 units/l. A diagnosis of focal rhabdomyolysis and left brachial plexopathy was made. Focal rhabdomyolysis with associated plexopathy is an uncommon but recognized complication of acute heroin use. Chronic ethanol use may have a "sensitizing" role in the pathogenesis of this syndrome.

Acute Disease↗
PubMed1999

Exertional myalgia syndrome associated with diminished serum ammonia elevation in ischemic exercise testing.

A 36-year-old man with chronic severe exertional myalgias had a normal serum lactate elevation and diminished serum ammonia elevation on an ischemic forearm exercise test (IFET). The IFET is commonly performed in the evaluation of patients with complaints of exertional myalgias, cramps, and rhabdomyolysis. The finding of a normal serum lactate elevation and a diminished serum ammonia elevation after ischemic exercise is usually considered indicative of myoadenylate deaminase deficiency. However, myoadenylate deaminase activity was normal in this man's muscle biopsy specimen. This case suggests that a diminished serum ammonia elevation in the IFET is not always indicative of myoadenylate deaminase deficiency, a disorder of ammonia production. A diminished serum ammonia elevation in the IFET could also reflect an impairment of net ammonia efflux from muscle into blood.

AMP Deaminase↗
PubMed1999

Delayed diffuse upper motor neuron syndrome after compressive thoracic myelopathy.

A 54-year-old man developed progressive spastic paraparesis beginning 2 weeks after a back injury caused by a subacute compressive thoracic myelopathy attributable to a post-traumatic arachnoid cyst. Three to 18 months after surgical decompression of the thoracic arachnoid cyst, the patient developed a diffuse predominantly upper motor neuron syndrome characterized by spastic quadriparesis, pseudobulbar paresis, and pseudobulbar affect. Retrograde corticospinal tract degeneration and upper motor neuron death after spinal cord injury is recognized. This case suggests that focal upper motor neuron injury can occasionally precipitate diffuse upper motor neuron dysfunction.

Arachnoid Cysts↗
PubMed1998

Nonrandom sequence of slope-intercept estimates in longitudinal gompertzian analysis suggests biological relevance.

The significance of intersections in age-specific mortality rate distributions could be attributed to a fundamental statistical relationship between estimates of slope and intercept. A strong negative correlation between estimates of slope and intercept is often observed in simple linear regression problems. The net result is that the family of lines generated by repetitive estimates of slope and intercept in a static experimental situation will tend to intersect at a common point. This statistical relationship between slope and intercept, however, should be random with respect to the time-ordered sequence of slope and intercept estimates. Annual paired slope and intercept estimates derived using the method of longitudinal Gompertzian analysis of age-specific mortality rates for men and women in the United States from 1900 to 1988 were analyzed to determine if they varied randomly. The probability that the observed sequence in these annual paired slope-intercept estimates was random is less than 10(-50) for both men and women. This finding essentially excludes the possibility that intersections in age-specific mortality rate distributions reflect a fundamental statistical relationship between slope and intercept and further suggests biological relevance for the method of longitudinal Gompertzian analysis.

Female↗
PubMed1998

The aging population: implications for the burden of neurologic disease.

The aging population has had a significant impact upon the societal burden of several neurologic disorders, such as Alzheimer's disease, primary malignant brain tumor, Parkinson's disease, and amyotrophic lateral sclerosis. The increased burden is the result of more than just the dramatically increasing number of elderly individuals. This profound demographic change in the age structure of populations in developed nations is primarily the result of increasing survival. This differential survival over time, and its corresponding less selective culling effect on the surviving population gene pool, is an additional explanation for the observed increasing frequency of several neurologic diseases associated with senescence.

Aged↗
PubMed1998

Aging, increasing genomic entropy, and neurodegenerative disease.

The genome, as biologic information, can be conceptualized in terms of entropy. The second law of thermodynamics dictates that entropy must increase over time. Consequently, aging can be viewed as increasing genomic entropy. Genetic instability is the biophysical correlate of increasing genomic entropy. Rates of increasing genomic entropy can be determined from age-specific mortality rate dynamics (e.g., Parkinson's disease and amyotrophic lateral sclerosis). These observations are consistent with a model of neurodegenerative disease as a manifestation of increasing genomic entropy with aging.

Aged↗
PubMed1998

Ethanol level differential between postmortem blood and subdural hematoma.

Alcohol use is a major risk factor for accidental injury and death. However, when death occurs several hours after injury, ethanol in the blood may be absent or low. Ethanol in sequestered hematomas has been used to retrospectively implicate alcohol as a contributing factor at the time of injury. A 69-year-old man died from a large acute subdural hematoma. He had been seen in a hospital emergency department 8 to 12 hours before his death for treatment of two lacerations (one on the head) that occurred during a fall. Postmortem blood ethanol was 0.07%, and subdural hematoma ethanol was 0.04%. This ethanol level differential between the postmortem blood and the subdural hematoma indicates that this man had consumed alcohol after being released from the hospital.

Accidental Falls↗
PubMed1997

Assessing quality of care. The limitation imposed by Condorcet paradox.

Condorcet paradox can be used to illustrate the mathematical impossibility of consistently ranking societal choices that are based on individual values. Quality-of-care measures reflect the values and interests of individuals (for example, physicians, patients, and payers) with differing perspectives of health care. Accordingly, appropriate decision making, technical performance, patient satisfaction, outcome, and cost-effectiveness are all valid examples of quality measures. Any attempt to prioritize or combine quality measures should be resisted if Condorcet paradox is to be avoided. The most consistent strategy is to strive to increase quality in each and every facet of its assessment.

Cost-Benefit Analysis↗
PubMed1997

Rolandic epilepsy and cortical dysplasia: MRI correlation of epileptiform discharges.

An 8 year-old girl presented with simple facial motor seizures. Although the electroencephalogram (EEG) demonstrated left hemisphere centrotemporal spikes with features consistent with benign rolandic epilepsy, magnetic resonance imaging (MRI) indicated a left hemisphere focal cortical dysplasia. MRI-assisted EEG dipole analysis of the spikes suggested that the rolandic fissure rather than the focal cortical dysplasia was the origin of the epileptic spike discharge. This noninvasive method may be a useful adjunct in evaluation of some patients with epilepsy and focal superficial cerebral lesions.

Brain Mapping↗
PubMed1997

Deprenyl, excess mortality, and epidemiological traps.

Compared with the findings for an age-matched group not taking deprenyl, a higher risk of mortality in Parkinson's disease patients taking deprenyl has recently been reported. Since a biological basis for this observation was not apparent, an epidemiological explanation was sought. Expected mortality over a 6-year period in four hypothetical age-matched groups was determined. Although groups were age matched, ages of individuals within the groups varied. Variation of individual ages within each group, without affecting the age-match comparability, produced a marked variation in expected group mortality. Mortality comparisons between age-matched groups can be invalid. This epidemiological trap might account for the recent unexplained high mortality observed in a group of Parkinson's disease patients taking deprenyl.

Age Factors↗