Measuring absorption coefficients in small volumes of highly scattering media: source-detector separations for which path lengths do not depend on scattering properties.

The noninvasive measurement of variations in absorption that are due to changes in concentrations of biochemically relevant compounds in tissue is important in many clinical settings. One problem with such measurements is that the path length traveled by the collected light through the tissue depends on the scattering properties of the tissue. We demonstrate, using both Monte Carlo simulations and experimental measurements, that for an appropriate separation between light-delivery and light-collection fibers the path length of the collected photons does not depend on scattering parameters for the range of parameters typically found in tissue. This is important for developing rapid, noninvasive, and inexpensive methods for measuring absorption changes in tissue.

Quantitative measurement of porphyrins in biological tissues and evaluation of tissue porphyrins during toxicant exposures.

Porphyrins are formed in most eukaryotic tissues as intermediates in the biosynthesis of heme. Assessment of changes in tissue porphyrin levels occurring in response to the actions of various drugs or toxicants is potentially useful in the evaluation of chemical exposures and effects. The present paper describes a rapid and sensitive method for the extraction and quantitation of porphyrins in biological tissues which overcomes difficulties encountered in previously described methods, particularly the loss of porphyrins during extraction and interference of porphyrin quantitation by coeluting fluorescent tissue constituents. In this procedure 8- through 2-carboxyl porphyrins are quantitatively extracted from tissue homogenates using HCl and methanol and are subsequently separated from potentially interfering contaminants by sequential methanol/phosphate elution on a C-18 preparatory column. Porphyrins are then separated and measured by reversed-phase high-performance liquid chromatography and spectrofluorometric techniques. Recovery of tissue porphyrins using this method is close to 100% with an intraassay variability of less than 10%. We have employed this procedure to measure liver and kidney porphyrin concentrations in male Fischer rats and to define the distinctive changes in tissue porphyrin patterns associated with treatment with the hepatic and renal porphyrinogenic chemicals, allylisopropylacetamide, and methyl mercury hydroxide, respectively. This method is applicable to the measurement of tissue porphyrin changes resulting from drug or toxicant exposures in clinical, experimental or environmental assessments.

Folates and post partum depression.

Hypofolatemia can cause psychiatric disturbances of a depressive nature. Pregnancy and delivery are often associated with hypofolatemia. This study was conducted to determine if hypofolatemia at day 3 post partum is a risk factor for baby blues or post partum depression. To study this hypothesis, 131 post partum women were followed prospectively for the 3 months immediately following delivery. 19% were found to have 'baby blues', as defined by a score greater than 20 on Pitt's scale (Pitt, 1968, J. Psychiatry 114, 1325-1335) and 12% had post partum depression as defined by a score greater than 7 on QD2A scale (Pichot et al., 1984, Rev. Psycholog. App. 34, 229-250, 323-340), within the three months post partum. No relationship was observed between the serum or erythrocyte folate levels on the third day following delivery and the maternal post partum depression scores. A statistically significant correlation between post partum depression and previous psychiatric disturbance was, however, observed.

Prophylactic efficacy of maprotiline on unipolar depression relapse.

BACKGROUND: Although antidepressant medications have been in use for about 30 years, the question remains about their utility in the prophylaxis of recurrent depression. The purpose of this study was to evaluate the efficacy of maprotiline, a tetracyclic antidepressant, for depression prophylaxis. METHOD: We conducted a vast, prospective, multicenter, double-blind, placebo-controlled study of 1141 outpatients suffering from depression and treated with maprotiline or placebo for 1 year. The very large size of the study population allowed for the testing of two drug doses. The study design included a pre-inclusion treatment phase that assured that all study patients had recently suffered from a depressive episode and were in remission at the time they were randomized into two treatment groups (1 and 1/2 tablet of maprotiline 75 mg) and two control groups (1/2 and 1 tablet of placebo). RESULTS: The actuarial relapse rate at 1 year was 16% for maprotiline 75 mg, 1 tablet; 23.8% for maprotiline 75 mg, 1/2 tablet; 31.5% for 1 tablet placebo, and 37.5% for 1/2 tablet placebo. The difference between each group is statistically significant, except for the difference between the two placebo groups. The actuarial incidence of adverse drug reactions during the year was not statistically significant between the treatment and control groups. CONCLUSIONS: This study demonstrates maprotiline's prophylactic effectiveness for depressive relapses, the 75-mg dose being more effective than the 37.5-mg dose. The patients' tolerance of maprotiline therapy was satisfactory at both doses with prolonged prescription.