Objective criteria for reporting language dominance by intracarotid amobarbital procedure

We propose a standardized method for reporting language lateralization by intracarotid amobarbital procedure (IAP). We retrospectively reviewed 165 IAPs, and classified language lateralization as left, right, or bilateral by three different methods, all based on the duration of speech arrest following each injection: absolute duration, side-to-side difference, and a "laterality index" defined as (L-R/L+R). Cutoff values were obtained by studying a pure subgroup of left hemisphere dominant right-handed subjects. In 142 patients (86%), the classification remained unchanged among all three methods: left in 112 (79%), right in 19 (13%), and bilateral in 11 (8%). In the other 23 patients (14%), language classification varied among the three criteria used. The change of category was never between left and right, and always involved bilateral language. Thus, this index may be helpful in standardizing and comparing IAP results from different series.     

Evaluation of a pneumonia practice guideline in an interventional trial

There are few available data to define the medically necessary duration of stay for patients hospitalized with pneumonia. Therefore, we investigated the safety and effectiveness of a practice guideline that provided information about switching patients from parenteral to oral antimicrobials and early hospital discharge. The study was a prospective controlled study with an alternate month design. The practice guideline was studied in 146 "low-risk" pneumonia patients hospitalized during a 22-month period. Medical care consistent with the practice guideline occurred in 64% and 76% of patients during control and intervention periods, respectively (p=0.15). There were no differences in patient outcomes in the control and intervention groups when measured 1 mo after hospital discharge, including hospital readmission rates, health-related quality of life, and patient satisfaction. Explicit and implicit review revealed that 98.6% (95% confidence interval [CI]: 95.1%, 99.8%) of low-risk patients would not have benefited from continued hospitalization after the fourth hospital day. The 30-d survival rate of the low-risk pneumonia patients was 99.3% (95% CI: 96.2%, 100%) and patient outcomes appeared to be favorable compared with previously published values. We conclude that duration of hospital stay was frequently consistent with the practice guideline in both study groups, and patient outcomes remained unchanged. The guideline will require additional testing before it can be recommended for use.     

Maturational differences in chlorpyrifos-oxonase activity may contribute to age-related sensitivity to chlorpyrifos

Chlorpyrifos (CPF), a commonly used cholinesterase-inhibiting insecticide, is lethal at much lower doses to young animals than adults. To explain this higher sensitivity in younger animals, we hypothesized that young rats have less chlorpyrifos-oxonase (CPFOase) activity than adults. To test this hypothesis, CPFOase activity was measured in the brain, plasma, and liver of male, postnatal day 4 (PND4) and adult (PND90) Long-Evans rats. CPFOase is biochemically defined as a Ca(2+)-dependent A-esterase that hydrolyzes chlorpyrifos-oxon (CPFO), the active metabolite of CPE. No brain CPFOase activity was detected at either age. Plasma and liver CPFOase activities were markedly lower at PND4 compared to adult: PND4 plasma and liver CPFOase activities were 1/11 and 1/2 the adult plasma and liver activities, respectively. Because the Km of CPFOase activity was high (i.e., 210-380 microM), it was important to determine if this CPFOase activity could hydrolyze physiologically relevant concentrations (i.e., nM to low microM) of CPFO. This was accomplished by comparing the shifts in the tissue acetylcholinesterase (AChE) IC50 for CPFO in the presence or absence of CPFOase activity. One would expect an increase in the "apparent" IC50 if CPFOase hydrolyzes substantial amounts of CPFO during the 30 minutes the tissue is preincubated with the CPFO. In the adult, both plasma and liver AChE apparent IC50 values were higher in the presence of CPFOase activity, suggesting that the CPFOase in those tissues was capable of hydrolyzing physiologically relevant concentrations of CPFO within 30 minutes. In young animals, however, there was less of a shift in the IC50 curves compared to the adult, confirming that the young animal has less capacity than the adult to detoxify physiologically relevant concentrations of CPFO via CPFOase.     

Analysis of failures and poor results of lumbar spine surgery

The failures and poor results of lumbar spine surgery are analyzed in a retrospectively study of 105 consecutive patients referred to the authors for evaluation during 1976. Those who had a history of industrial or vehicular accident outnumbered others by about two to one. Review of histories, physical findings, and myelograms in most of the patients failed to substantiate the diagnosis of ruptured disc or nerve root compression. Many of the failures occurred in thos patients in whom little if any evidence of nerve root compression was found. The indications for surgery were poor in this group. Other failures occurred in patients who had improper, incomplete, or inadequate operations, especially those with lumbar spondylosis, a retained fragment of disc, or surgery at the wrong level. In addition to failure, poor results were recorded in patients who had significant nerve root or cauda equina injury from surgery, associated "arachnoiditis" which is thought to result from surgical trauma in many instances, or multiple operations leading to a hopelessly disabled state.