Blue-green laser-induced fluorescence from intact leaves: actinic light sensitivity and subcellular origins.

Remote sensing of the health status of vegetation should be possible by using UV laser-induced fluorescence; nevertheless, the molecular origin of the leaf blue-green fluorescence emission is still unknown. In order to investigate possible relations of this fluorescence to the photosynthetic apparatus, we looked for its intensity changes after the addition of actinic light. The lack of any changes outside the chlorophyll fluorescence bands (Kautsky effect) was further investigated by collecting spectra from cell, protoplast, and chloroplast suspensions. These spectra led us to ascribe most of the blue-green laser-induced fluorescence that is detectable on a leaf by UV laser excitation to extrachloroplastic compartments. In active chloroplast suspensions blue fluorescence from photosynthetically reduced nicotinamide adenine dinucleotide phosphate (NADPH) has been detected and should be characterized by time-resolved fluorescence techniques.

The influence of thyroid hormones on colony growth of peripheral CFU-GM from normal and leukemic subjects.

In order to clarify the alterations of granuloblastic cells in chronic and acute myeloid leukemia, the colony growth behavior of cultured CFU-GM from the peripheral blood of normal and leukemic subjects was examined in basal conditions and after adding to the medium T3 or T4 and/or thioproline and/or flurbiprofen. These drugs had in previous investigations proved their ability to modify cellular receptors and the uptake of thyroid hormones. The study was carried out in semisolid (double agar layer) and liquid medium, utilizing the techniques described previously. Both thyroid hormones enhanced the colony growth from normal peripheral blood CFU-GM and the response was more evident with T4 than T3. The effect on leukemic CFU-GM (from CML and AML) was less clear, probably due to the presence in leukemic cells of a defect of cellular uptake and to the utilization of T3 and T4. Indeed, on addition to the culture medium of thioproline, which modifies membrane permeability, and of fluorbiprofen, which inhibits PGE synthesis, the colony number and growth from leukemic CFU increased considerably in accordance with the results of our previous studies on these substances showing that they are able to modify cellular receptors for thyroid and several other hormones.

[Penbutolol and arterial hypertension]. / Penbutololo e ipertensione arteriosa.

Penbutolol has proved particularly effective and suitable for the treatment, even on a long-term basis, of recently developed hypertension, especially in its hyperkinetic forms. The drug produces minimal side effects, is well tolerated and gives an early therapeutic response. In addition penbutolol does not cause any significant alterations in the biohumoral parameters of the patients treated and is ideal for combination with dihydralazine, reserpine and dihydrochlorotiazide in the treatment of more stubborn cases, making it possible to reduce the doses of the other drugs without causing bradycardia.