These findings suggest that "effective" placebo treatment induces changes in brain function that are distinct from those associated with antidepressant medication. If these results are confirmed, cordance may be useful for differentiating between medication and placebo responders.

Previous studies have shown that changes in brain functionClinicians long have observed a lag time of several weeks between the initiation of antidepressant treatment and clinical response for many patients (Hyman and Nestler 1996;Katz et al. 1996). Some individuals do have early symptomatic improvement, and this has been reported to predict further improvement over the next several weeks (Nierenberg et al. 1995). Reports have suggested that some physiologic changes are seen shortly after initiation of treatment (Sulser 1989;Beck 1995;Dahmen et al. 1997). No clinically practical physiologic predictor of treatment response has yet been identified with these techniques, however, and the relationship of early physiologic changes to eventual clinical outcome remains incompletely understood.Quantitative electroencephalography (QEEG) has been used as a physiologic measure in efforts to address these questions. Prior work with "pharmaco-EEG" techniques has shown that the administration of antidepressant compounds yields reproducible changes in EEG activity in healthy control subjects within a few hours of dosing (Saletu et al. 1982(Saletu et al. , 1983(Saletu et al. , 1986(Saletu et al. , 1987(Saletu et al. , 1987 Grunberger 1985, 1988;Sannita et al. 1983;Sannita 1990; Early Prefrontal Changes in Depression 121Itil et al. 1984;Herrmann et al. 1991;Luthringer et al. 1996). The relationship of these immediate EEG changes in control subjects to eventual clinical response in a depressed population is unclear. Other QEEG work with depressed subjects has found that changes from baseline in theta power early in the course of treatment may characterize groups of depressed patients who are more likely to respond to antidepressant treatment (Ulrich et al. 1994). Unfortunately, the overlap in the value of these changes between responder and nonresponder groups precluded the use of this measure in response prediction for individual subjects, and prior research did not indicate how to relate changes in theta power to other measures of regional brain activity (e.g., regional cerebral blood flow or metabolism). We previously have shown that absolute and relative power are complementary measures of brain activity (Leuchter et al. 1993). A relatively new QEEG measure, "cordance," combines information from both absolute and relative power measures (Leuchter et al. 1994a(Leuchter et al. , 1994b. The algorithm yields two indicators: a categorical value ("concordant" or "discordant" state) and a numerical value for each electrode. In an earlier report with the categorical measure , we observed that depressed subjects exhibiting the concordant state prior to treatment had better treatment outcomes when treated with fluoxetine than did subjects with the discordant state. In this report, we use the num*erical values of cordance, because they allow examination of changes in regional brain activity with treatment. In validation against data collected simultaneously with [H 2 15O]-positron emission tomography (PET), cordance values in the the...

Preliminary findings support the potential of yoga as a complementary treatment of depressed patients who are taking anti-depressant medications but who are only in partial remission. The purpose of this article is to present further data on the intervention, focusing on individual differences in psychological, emotional and biological processes affecting treatment outcome. Twenty-seven women and 10 men were enrolled in the study, of whom 17 completed the intervention and pre- and post-intervention assessment data. The intervention consisted of 20 classes led by senior Iyengar yoga teachers, in three courses of 20 yoga classes each. All participants were diagnosed with unipolar major depression in partial remission. Psychological and biological characteristics were assessed pre- and post-intervention, and participants rated their mood states before and after each class. Significant reductions were shown for depression, anger, anxiety, neurotic symptoms and low frequency heart rate variability in the 17 completers. Eleven out of these completers achieved remission levels post-intervention. Participants who remitted differed from the non-remitters at intake on several traits and on physiological measures indicative of a greater capacity for emotional regulation. Moods improved from before to after the yoga classes. Yoga appears to be a promising intervention for depression; it is cost-effective and easy to implement. It produces many beneficial emotional, psychological and biological effects, as supported by observations in this study. The physiological methods are especially useful as they provide objective markers of the processes and effectiveness of treatment. These observations may help guide further clinical application of yoga in depression and other mental health disorders, and future research on the processes and mechanisms.

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Francisella tularensis, the etiological agent of tularemia, is found throughout the Northern hemisphere. After analyzing the F. tularensis genomic sequence for potential variable-number tandem repeats (VNTRs), we developed a multilocus VNTR analysis (MLVA) typing system for this pathogen. Variation was detected at six VNTR loci in a set of 56 isolates from California, Oklahoma, Arizona, and Oregon and the F. tularensis live vaccine strain. PCR assays revealed diversity at these loci with total allele numbers ranging from 2 to 20, and Nei's diversity index values ranging from 0.36 to 0.93. Cluster analysis identified two genetically distinct groups consistent with the current biovar classification system of F. tularensis. These findings suggest that these VNTR markers are useful for identifying F. tularensis isolates at this taxonomic level. In this study, biovar B isolates were less diverse than those in biovar A, possibly reflecting the history of tularemia in North America. Seven isolates from a recent epizootic in Maricopa County, Ariz., were identical at all VNTR marker loci. Their identity, even at a hypervariable VNTR locus, indicates a common source of infection. This demonstrates the applicability of MLVA for rapid characterization and identification of outbreak isolates. Future construction of reference databases will allow faster outbreak tracking as well as providing a foundation for deciphering global genetic relationships.