[Ophthalmological alterations at the initial diagnosis of HIV infection]

Acquired immunodeficiency syndrome (AIDS) caused by the human immunodeficiency virus (HIV), is one of the most important infectious causes of death in the twentieth and twenty-first centuries. Ocular manifestations can appear in particular when the CD4 cell count is low. This article presents a case report of a 38-year-old homosexual man in whom HIV microangiopathy retinopathy syndrome (MAPS) was found during the assessment of the initial HIV diagnosis. Typical findings in MAPS are conjunctival and retinal vessel abnormalities, cotton wool spots as well as intraretinal hemorrhages. Loss of vision is a rare complication but MAPS shows an impairment of the immune status and is also associated with a higher mortality.

Relationship between structure and antioxidative properties of some 3-formylchromone derivatives

Flavonoids, which generally exhibit very good antioxidant properties, contain the chromone unity. The work elucidates the relation between chemical structure of chromones and their ability to scavenge DPPH radicals. The work deals with antioxidative properties of some hydroxy derivatives of 3-formylchromones (without substituent, 6-hydroxy-, 7-hydroxy-, 7,8-dihydroxy-). It was found that the last two derivatives scavenge DPPH radicals, whereas the first two ones do not. It was demonstrated that the presence and location of hydroxyl groups play a crucial role for antioxidative activity of 3-formylchromones. The scavenging of DPPH radicals runs through H(+) abstraction from hydroxyl groups of formylchromones. The DPPH scavenging by 3-formylchromones with hydroxyl group in the 7th position is connected with the formation of more stable form of anion than in the case of 6-hydroxy-3-formylchromone. Calculation heats of formations of studied formylchromone anions confirmed this fact. All studied 3-formylchromones did not scavenge HO( ) radicals, what supports H(+) abstraction mechanism of DPPH scavenging.

Triplet states as non-radiative traps in multichromophoric entities: single molecule spectroscopy of an artificial and natural antenna system

Energy transfer in antenna systems, ordered arrays of chromophores, is one of the key steps in the photosynthetic process. The photophysical processes taking place in such multichromophoric systems, even at the single molecule level, are complicated and not yet fully understood. Instead of directly studying individual antenna systems, we have chosen to focus first on systems for which the amount of chromophores and the interactions among the chromophores can be varied in a systematic way. Dendrimers with a controlled number of chromophores at the rim fulfill those requirements perfectly. A detailed photophysical study of a second-generation dendrimer, containing eight peryleneimide chromophores at the rim, was performed 'J. Am. Chem. Soc., 122 (2000) 9278'. One of the most intriguing findings was the presence of collective on/off jumps in the fluorescence intensity traces of the dendrimers. This phenomenon can be explained by assuming a simultaneous presence of both a radiative trap (energetically lowest chromophoric site) and a non-radiative trap (triplet state of one chromophore) within one individual dendrimer. It was shown that an analogue scheme could explain the collective on/off jumps in the fluorescence intensity traces of the photosynthetic pigment B-phycoerythrin (B-PE) (Porphyridium cruentum). The different values of the triplet lifetime that could be recovered for a fluorescence intensity trace of B-PE were correlated with different intensity levels in the trace, suggesting different chromophores acting as a trap as function of time.

Study of diastereomeric thioureas formed with a new chiral derivatizing agent

(1S,2S)-1,3-Diacetoxy-1-(4-nitrophenyl)-2-propyl isothiocyanate ((S,S)-DANI) was recently introduced as a new chiral derivatizing agent for the enantioseparation of amino compounds. In the present study, diastereomeric derivatives of racemic amino acids were formed with (S,S)-DANI. The thioureas produced were distinguished by means of infrared spectroscopy, theoretical calculations and high-performance liquid chromatography. The differences observed between the corresponding diastereomers by the independent methods are considered to prove the applicability of the new reagent in the field of enantiomer separation.

Activity of some 3-formylchromone derivatives on the induction of chloroplast-free mutants in Euglena gracilis

The hereditary bleaching test on Euglena gracilis was used for detecting extranuclear mutations. The highest bleaching activity (induction of the chloroplast-free mutants) was shown by the 6-R-3-formylchromones. On the other hand, bleaching-inactive 6-R-3-formylchromone acylhydrazones (derived from gallic and salicylic acids), added at sufficient concentrations in the case of chloroplast mutagenesis in E. gracilis, act as a potent antimutagen. This effect appeared to be a unique feature of chromone derivatives, but was dependent on the type of mutagen. These substances were very effective against the bleaching activity of acridine orange, and were less effective against N-methyl-N'-nitro-N-nitrosoguanidine. The genotoxic effects of these mutagens was reduced, especially during the first stages of induction of this specific cytoplasmic mutation. The experimental study of mutagenicity and antimutagenicty of 3-formylchromone hydrazones was reinforced by data obtained by the semi-empirical AM1 method and lipophilicity values.

[Functional scintigraphic blood pool study. A radiologic technic for non-invasive study of pharmacologically induced blood volume fluctuations]

After in-vivo labeling of red blood cells with 99mTcO4, the radioactivity of different parts of the body is proportional to the regional blood volume. This technique allows the simultaneous registration of drug-induced changes of the local blood volume. We examined the influence of nitroglycerin on the blood volume distribution in patients with coronary artery disease (n = 10) and chronic heart failure (n = 8). Compared with the controls (n = 8) we observed in the nitroglycerin-groups a significant decrease of blood volume over the heart and the liver, whereas there was an increase of the blood volume over the extremities. It is pointed out that functional whole-body scanning is a useful radiological technique for the non-invasive study of pharmacologically caused changes of the local blood volume in man.

[Diagnosis of myocardial metastases by sectorechocardiography (author's transl)]

A case of myocardial metastases due to a malignant bone tumour was diagnosed by sectorechocardiography. The clinical data and the findings of echocardiography and pathology are presented, the value of echocardiography in the diagnosis of myocardial metastases is discussed.

Impaired dopamine function and muscular rigidity induced by 6-aminonicotinamide in rats

In corpus striatum, 6-aminonicotinamide (6-AN), 10 mg/kg i.p. lowered the concentration of dopamine and markedly reduced the disappearance of dopamine after synthesis inhibition with alpha-methyl-p-tyrosine. In the dopamine-rich part of the limbic system, the formation of DOPA after decarboxylase inhibition with 3-hydroxybenzylhydrazine was decreased. In diencephalon, 6-AN altered neither the steady-state level nor the utilization of noradrenaline. The data suggest that the muscular rigidity induced by 6-AN may be associated with disruption of dopaminergic transmission.

Spastic paresis after 6-aminonicotinamide: metabolic disorders in the spinal cord and electromyographically recorded changes in the hind limbs of rats

In rats the application of 10 mg/kg 6-amino-nicotinamide (6-AN) leads to an accumulation of 6-phosphogluconate, by inhibition of 6-phosphogluconate dehydrogenase in the pentose phosphate pathway, in the cells of the spinal cord. The accumulation reaches its maximum after 18-24 h. It seems that there exists a relationship between the accumulation of 6-phosphogluconate and the lesion of the neuroglia, which is found in electron microscopic studies. Symptoms of a spastic paresis only develop later when the spinal interneurones are destroyed as a consequence of the lesion of the neuroglia. The accumulation of 6-phosphogluconate almost exceeds the 400 fold of the norm. No considerable differences are found between the effects of a dose of 35 mg 6-AN/kg and one of 10 mg 6-AN/kg. Free gluconate is identified enzymically in the cells of the spinal cords of the rats treated with 6-AN. The compound is very probably formed by dephosphorylation and diffuses into the blood. 6-Phosphogluconate is an inhibitor of the phosphoglucose isomerase. Its accumulation shifts the equilibrium towards glucose 6-phosphate. The lactate concentration decreases as compared with the untreated controls. Muscular action potentials are recorded extracellularly with a concentric needle electrode from the musculus gastrocnemius of rats treated with 6-AN. First activations of the electromyograms are found 48 h after the application of 10 mg 6-AN/kg. The electrical activities increase during the time in which a progressive destruction of the interneurones occurs. The electromyogram displays a permanent state of excitation with high amplitudes and an increased frequency. The continuity and intensity of the increased activity recorded by the electromyograph is the most important pathological finding. p-Chlorophenyl-GABA and, still more so, chlorpromazine cause temporary reduction of the excitation processes and an electromyogram nearly at rest. Under the same conditions, haloperidol is only slightly effective. The symptoms developed by the chemical destruction of the interneurones of the spinal cord, with rigidity and spasticity of the hind limbs, are suitable for testing antispastic drugs.