The efficacy of St. John's Wort in patients with minor depressive symptoms or dysthymia--a double-blind placebo-controlled study.

INTRODUCTION: We studied the efficacy of St. John's Wort compared with placebo in patients with minor depressive symptoms or dysthymia, with the main focus on which diagnostic entities are optimally amenable to treatment with two different doses of Hypericum, and which are not. METHODS: One hundred and fifty patients, 25-70 years old, meeting ICD-10 criteria for mild or moderately severe depressed episodes or with dysthymia, and having a 17-item Hamilton Depression Scale for Depression (HAM-D) total score between 7 and 17, were randomly assigned to an extract. The extract, PM235, manufactured by Cederroth International AB, Sweden, was given t.i.d. in a lower (0.12% hypericine) or a higher (0.18% hypericine) formulation, based on 270mg extractions or identical placebo. Clinical response was defined by HAM-D as a 50% reduction and/or a score 7. The Beck Depression Inventory (BDI) and Visual Analog Scales (VAS) were used as secondary efficacy parameters. Measures were conducted at screening, baseline, and after 3 and 6 weeks of treatment. RESULTS: We found a large discrepancy in response between dysthymic and non-dysthymics, the latter seemingly more sensitive to Hypericum. HAM-D showed tendency but no significance toward a more frequent improvement of the non-dysthymics treated with Hypericum (p=0.057). BDI criteria showed significance (p=0.045) for both doses of Hypericum compared to placebo. Pooling high- and low-dose groups together, a significant reduction for HAM-D7 and BDI criteria was found among non-dysthymic patients (p=0.03). Significant improvement in response to Hypericum was found in symptoms reflected by VAS - again only in non-dysthymic patients (p=0.041). DISCUSSION: We observed, a tendency toward a more frequent significant improvement of the non-dysthymic patient treated with PM235, though this did not reach the level of statistical significance. In a secondary analysis, pooling both hypericine-treated groups concluded that Hypericum has a clinical significant effect in minor depressed patients with HAM-D up to 17. This finding was significant only in non-dysthymic patients.

Plant Viability as a Function of Temperature Stress (The Richards Function Applied to Data from Freezing Tests of Growing Shoots).

Frost resistance of growing Salix viminalis L. shoots was determined by rating mortality percentage under two commonly used freezing conditions: a condition in which plants were encased in crushed ice and another in which plants were moistened with tap water prior to freezing. The mortality-temperature data were fitted with a logistic function (having a fixed inflection point halfway between the asymptotes) and with a Richards function, which is a double asymptotic sigmoid function with a variable inflection point. Different frost resistance curves were obtained, depending on the freezing conditions used. However, conditions were inadequate for efficient ice nucleation under either condition. This implies that the applied freezing conditions are not suitable when the purpose is to induce and duplicate early ice crystal formation conditions. The Richards derivatives were negatively skewed in the one case and positively skewed in the other case, giving inflection points, as a function of the upper asymptote, situated at 0.37 when shoots were frosted in the presence of ice and at 0.81 when shoots were frozen in the presence of added moisture. These values differed significantly from 0.50, through which the logistic function would have forced the curves. Because of the significant asymmetry in these frost-resistance curves, the Richards function led to a more accurate reflection of the temperature-mortality course of growing Salix stems than the logistic function. The Richards function possesses the flexibility needed to describe plant injury response in terms of physical and plant physiological mechanisms. Therefore, the Richards function is recommended rather than the logistic function for the assessment of frost resistance.