Fourier transform infrared spectroscopy study of CO electro-oxidation on Pt(111) in alkaline media.

In this work we investigate the electro-oxidation of CO on Pt(111) in alkaline solution by using Fourier transform infrared spectroscopy (FTIRS), to determine the adsorption sites of the CO, the intermediate species and the final oxidation product as a function of the applied potential. Multiple CO vibration bands (on-top, bridge and 3-fold hollow site) are observed on the Pt(111) electrode, their distribution and potential dependence being strongly dependent on the surface treatment. Spectroscopic results show that the final reaction product is carbonate and suggest that adsorbed carbonate blocks the access of CO from the (111) terrace to the active sites (i.e., step and kink sites).

Time-related variations of some biochemical parameters in patients with short- or long-lasting post-traumatic coma.

The variation in time of some blood biochemical parameters was investigated in 100 patients with acute head injury and coma of variable duration, in parallel with the clinical course. The purpose of this study was to establish possible correlations between the severity of the trauma (assessed according to the coma classification proposed by C. Arseni) and the variation of the parameters studied. The results show complex correlations between the biochemical events in the patient and the degree of brain function impairment initially and after some time. Long lasting coma (over 14 days) is associated with complex biochemical alterations representing an additional element for defining the clinical condition.

Acupuncture treatment of discopathic pain.

The authors present the effects of acupuncture in 50 patients showing discopathic pain. It is concluded that acupuncture treatment favours the reduction of drug consumption, and, implicitly, of iatrogenic pathology.

[A comparative study of plasma converting enzyme and renin in sarcoidosis]. / Studiul comparativ al enzimei de conversie si reninei plasmatice în sarcoidoza.

The paper reports on a comparative study of the conversion enzyme and plasmatic renin performed on a group of 55 patients, with clinical diagnosis of sarcoidosis and other lung diseases. Whereas the conversion enzyme showed important increases in active sarcoidosis and a tendency to the normal state after treatment with corticoids, the activity of the plasmatic renin remained the same, both before and after corticotherapy. The result obtained prove the practical usefulness of the dosage test of the conversion enzyme, in agreement with the literature data. They also point to the possible participation of the pulmonary SRA in the vascular and local enzymatic-chemical imbalances, suggesting the possibility of associating the conversion enzyme inhibitors to the treatment of sarcoidosis with corticoids.

[The involvement of adenosine and adenosine deaminase in experimental myocardial infarct]. / Implicatiile adenozinei si adenozindezaminazei în infarctul miocardic experimental.

By the ligature of the left coronary artery in the rat anesthetized with nembutal (10 mg/100 i.p.) a significant increase of the 5'-nucleotidase activity (Wooton method) was noticed 10 minutes after the left ventricle infarction (from an average value of 1038.5 +/- 187 mU/g tissue to 1537 +/- 225 mU/g fresh tissue). The adenosine desaminase levels spectrophotometrically determined by Denstedt technique, do not appear significantly modified 10 or 30 minutes after the left ventricle infarction. The chromatographically determined adenosine levels, by HPLC technique, decrease from the average value of 11.63 +/- 1.4 micrograms/mg PT to 8.60 +/- 1.0 micrograms/mg PT 30 minutes after infarction. The observed changes are explained by the conditions of hypoxia in the infarcted ventricle which lead to the raise in adenosine levels by activating the 5'-nucleotidase and their depression by a very fast metabolism of the same substance.

[The cardioprotective action of captopril during atrial electrostimulation]. / Studiul actiunii cardioprotectoare a captoprilului prin electrostimulare atriala.

The presence of R-A-A system components in all organs (heart included) has suggested a possible cardio-protective effect of the angiotensin conversion enzyme inhibitors as a result of coronary flow improvement. This effect would act irrespective of the well-known peripheral vascular effects: vasodilation, blood pressure decrease, pre- and postload reduction. By using the atrial pacing in the quantitative assessment of the anginal threshold and of the associated ECG alterations before and after the i.v. administration of 25 mg of captopril we could immediately evaluate the coronary reserves by estimating the efficiency of captopril in the patients with angina pectoris. The atrial pacing has been performed, by using the method suggested by Sowton, in 18 patients with typical angina. The increase of heart tolerance at exercise, the systolic dynamics improvement and the ejection fraction increase as well as the raising of the anginal threshold have been noticed in 15 of the patients. The blood pressure has evidenced no significant changes. After the administration of captopril, the ischemic ECG alterations have been less marked and their postpacing remains shorter. Our findings plead for a direct action of captopril on cardiac intrinsic R-A-A system in the normotensive patients suffering from angina pectoris.

[Variations in plasma angiotensin-converting enzyme and renin in sarcoidosis]. / Cercetari privind variatiile enzimei de conversie a angiotensinei si reninei plasmatice in sarcoidoza.

A comparative study of plasma angiotensin-converting enzyme and renin activity was carried out in 55 patients with sarcoidosis and other pulmonary diseases. The converting enzyme activity was significantly increased in active sarcoidosis, showing a tendency to return to normal values after corticoid treatment, while plasma renin activity remained unaltered both before and after corticotherapy. The obtained results confirm the usefulness of the converting enzyme measurements, as already shown by others. Attention is drawn on the possible involvement of the pulmonary renin-angiotensin system in the local vascular and enzymo-chemical alterations, suggesting the possibility of associating the converting enzyme inhibitors to the corticotherapy of sarcoidosis.

The ontogenetic evolution of cerebral renin and cathepsin D in the rat.

Renin and Cathepsin D activities were measured in different cerebral structures in foetuses, during the first month of life and in the adult rats. There are differences in the renin activity and cathepsin D activity both in the cerebral structures and during the ontogenetic development. While the cathepsin D was much increased in newly born animals as compared to foetuses and remained fairly constant during the rest of life, the cerebral renin activity was constantly decreasing toward adulthood. It was found that during the first two weeks after birth there is a renin activity increase in the cerebral cortex and hypothalamus, followed by a decrease and, at the end of the first month of life after birth, the values were equal to those found in adult animals. The same variations were found in the epiphysis between the 45th and 50th day after birth.

Evidence for the involvement of cerebral renin-angiotensin system (RAS) in stress analgesia.

Studies concerning variations of the central renin-angiotensin system (RAS) during immobilization stress in rats have shown a significant increase in renin-like activity in the hypothalamus and fronto-parietal cortex, together with a definite decrease in the hypophysis and pineal gland. The resultant stress analgesia is blocked by the previous administration of naloxone and saralasin (angiotensin II antagonist). The intracerebral administration of renin and angiotensin II produces an increase in latencies to thermoalgesic stimuli; this is reduced, as is immobilization stress, by naloxone and saralasin. Both chemical hypophysectomy obtained by dexamethasone pretreatment as well as surgical epiphysectomy block the stress-induced analgesia. The experimental data obtained argue in favour of the participation of the cerebral RAS in stress analgesia through the indirect mechanism of release of opioid peptides.

Evidence of the involvement of cerebral renin-angiotensin in stress analgesia.

Studies concerning the variations of the central renin-angiotensin system (RAS) during the immobilization stress in rats have shown a significant increase of the renin-like activity in the hypothalamus and the fronto-parietal cortex together with a manifest decrease in hypophysis and pineal gland. The resulted stress, analgesia, is blocked by the previous administration of naloxone and saralasin. The intracerebral administration of renin and angiotensin II increases the latency time to thermoalgesic stimuli which is reduced, as in the immobilisation stress, by naloxone and saralasin. The chemical hypophysectomy obtained by chronic treatment with dexamethasone, also inhibits the stress-induced analgesia. Epiphysectomy reduces all the same the analgesic effects of the immobilisation stress. The obtained experimental data argue in favour of the participation of the cerebral RAS in stress analgesia through the indirect mechanism of release of opioid peptides.

A comparative study of the renin-like activity in the heart and vascular system under various experimental conditions.

Renin-like activity in the heart and aorta of rats being slightly modified by binephrectomy, its variations in DOCA hypertension and infarcted ventricular muscle were studied. The daily i.p. administration of DOCA 12 mg/kg body weight for 35 days in male adult rats resulted in a significant decrease of renin activity in plasma and tissues of the heart, aorta, hypothalamus and hypophysis. In contrast to renin-like activity, cathepsin D measured in the same animals increased in all organs, except for the plasma. Similar changes of renin-like activity were observed in salt-loaded animals with 1.7% sodium chloride solution ad libitum for 35 days. In the infarcted myocardial ventricular muscle of the rats and rabbits, the tissue isorenin showed a tendency to decrease, associated with a significant increase in cathepsin D activity. Like in aorta, isorenin seems to be a different enzymatic entity of cathepsin D in the myocardial tissue. The measurement of isorenin content of the vascular endothelium and cardiac muscle fibers seems to reveal much higher amounts in the coronary vascular endothelium than in the myocardial fibres. The activation of the enzymatic angiotensin forming mechanisms in the coronary vascular bed could be one of the risk factors in myocardial infarction.