Two-photon photosensitized production of singlet oxygen.

Singlet molecular oxygen (a(1)Delta(g)) has been produced and optically detected upon two-photon nonlinear excitation of a sensitizer with a focused laser beam. The experiments were performed using toluene solutions with either a substituted difuranonaphthalene or a substituted distyryl benzene as the sensitizer. The data indicate that the two-photon absorption cross sections of the difuranonaphthalenes are comparatively large and depend significantly on the functional groups attached to the chromophore. The time-resolved 1270 nm phosphorescence signals used to characterize the production of singlet oxygen are limited in much the same way as signals from other two-photon spectroscopic studies (e.g., weak signals that can be masked by scattered radiation). Nevertheless, the two-photon singlet oxygen signals also reflect the unique advantages of this nonlinear optical technique (e.g., depth penetration in the sample afforded by irradiation in a spectral region void of the more dominant one-photon linear transitions and spatial resolution afforded by irradiation with a focused laser beam).

A quantitative EEG analysis of the effects of baclofen on man.

This investigation has been directed to estimate to what extent a GABA derivative, beta-(p-chlorophenyl)-gamma-aminobutyric acid (baclofen), is active at the cortical and subcortical level. Selected nonpsychotic patients with slight depression symptoms were given 30 mg of baclofen daily for a period of 3-5 weeks. Brief Psychiatric Rating Scale and Standardized Hamilton Interview for Depression were used for clinical evaluation. EEGs were recorded prior to and at different times during treatment. An automatic analysis completed by multivariant statistics of EEG spectral values was performed. EEG changes were characterized by a significant increase of slow waves and decrease of fast activity. These results can support the view that baclofen is effective even at the highest levels of the central nervous system.

Hypercalcemia due to primary hyperparathyroidism or malignant disease. Evaluated by means of biochemical tests and the steroid suppression test.

The cortisone suppression test and some biochemical tests were evaluated in 13 patients with hypercalcemia due to primary hyperparathyroidism (PHP) and in 10 with hypercalcemia due to a malignant disease. The biochemical tests revealed that serum chloride was significantly raised in patients with PHP compared to patients with malignant diseases, whereas no differences were observed with regard to the serum values of corrected calcium, serum phosphate, chloride/phosphate ratio, HCO3-. Although serum values of parathyroid hormone were higher in patients with PHP, a consider-able overlap was observed between values in the two patient groups. Corrected serum calcium values were significantly suppressed during cortisone administration in patients with malignant disease compared to patients wit PHP, whereas prednisolone had no suppressive effect. The positive predictive value of the test was 80.0% and the negative predictive value 66.7%. We conclude that there is still no entirely reliable method to distinguish between hypercalcemia due to PHP or malignant disease.

Pseudohypoparathyroidism. A 25-year delay in diagnosis.

The diagnosis of pseudohypoparathyroidism is often not made until many years after the onset of symptoms and signs characteristic of the disease. A case history presented here illustrates this and stresses the importance of determining the calcium concentration in plasma in all patients with attacks of sensory and motor phenomena.