Effects of a stable enkephalin analogue, (D-Met2,Pro5)-enkephalinamide, and naloxone on cortical blood flow and cerebral blood volume in experimental brain ischemia in anesthetized cats.

The effects of intracarotid injection of the stable enkephalin analogue (D-Met2,Pro5)-enkephalinamide (ENK) and intravenous administration of naloxone on the cerebrocortical blood flow (dye dilution method) and cerebral blood volume (CBV) (photoelectric method) were investigated during unilateral brain ischemia in anesthetized cats. Both parameters were measured simultaneously in the intact and ischemic (middle cerebral artery occluded) hemispheres. An intracarotid injection of ENK 0.5 mg/kg induced a significant increase in cortical vascular resistance and a -87% decrease in cerebrocortical blood flow from 25 +/- 3 to 4 +/- 3 ml/100 g/min, without CBV alteration in the ischemic hemisphere. Naloxone (1 mg/kg i.v.), on the other hand, induced a marked two-fold increase in cerebrocortical blood flow and a significant elevation of CBV from 5.9 +/- 0.5 to 7.4 +/- 0.7 vol% in the ischemic hemisphere. No change in cerebrocortical blood flow or CBV was observed in the intact hemisphere either after ENK or after naloxone administration. Arterial blood gases and hematocrit remained unchanged. On the basis of the present findings, we conclude that besides other factors, endogenous opioid mechanisms may also participate in ischemic cerebrovascular reactions and the cerebral circulatory effects of naloxone probably reflect its opiate receptor blocking property and not simply its other non-opiate-related actions.

Effects of (D-Met2,Pro5)-enkephalinamide and naloxone on pial vessels in cats.

To elucidate the fundamental actions of endogenous opioids and naloxone on the cerebral circulation, the effects of (D-Met2,Pro5)-enkephalinamide and naloxone on pial vessels were investigated in cats. Pial arteries (165.7 +/- 24.9 microns) were found to dilate after the intravenous administration of 1 mg/kg of (D-Met2,Pro5)-enkephalinamide, and a definite dilatation of 7.1-7.6% persisted for 15 min. Pial veins (100.6 +/- 20.2 microns) also dilated but to a lesser degree. The MABP (118.7 +/- 10.5 mm Hg) decreased by 20 mm Hg immediately after the injection, but gradually returned to the initial value 15 min later. The observed cerebral vasodilatation may be attributable to sympathetic inhibition mediated either by the presynaptic opiate receptors of the cerebral vessels or by the opiate receptors in the brainstem. After the intravenous administration of 1 mg/kg of naloxone, pial arteries (122.0 +/- 17.2 microns) showed a slight but significant dilatation of 2.3-5.3%. There were no significant changes in pial veins (87.0 +/- 12.4 microns). MABP (130.4 +/- 12.3 mm Hg) was slightly increased after the injection. Although the mechanism involved was unclear, the cerebral vasodilatation occurring after the administration of naloxone may contribute to its ameliorating effect on the neurological symptoms following cerebral ischemia.

Efficacy and tolerability of piroxicam-beta-cyclodextrin in the outpatient management of chronic back pain.

BACKGROUND: Piroxicam-beta-cyclodextrin (PBC) is the first nonsteroidal anti-inflammatory drug (NSAID), in which the active substance is complexed with the cyclic oligosaccharide cyclodextrin, which acts as an artificial receptor. This complex allows single molecules of the NSAID to be released adjacent to the gastrointestinal mucosa, instead of crystals. Since the piroxicam is immediately bioavailable in this formulation, the onset of action is similar to that of a parenteral drug. Since the time contact with gastric mucosa is reduced, the risk of direct-contact gastric irritation is also reduced. There is good evidence that PBC is beneficial in managing acute non-specific back pain (BP) but sufficient evidence on chronic BP is lacking. METHODS: Thirty-one eligible patients aged 18-85 years, resistant to previous therapy with different NSAIDs, were treated with PBC 20 mg once daily in a 40-day open-label noncomparative study. The patients experienced chronic BP defined as pain between the occipital region and gluteal fold, lasting for at least 6 weeks but not more than 6 months. Efficacy was assessed by changes in pain intensity, paravertebral tonus, functional impairment and morning stiffness using a 4-point numerical rating scale. Patients also self-assessed nocturnal and diurnal pain using the visual analogue scale. Tolerability was assessed by adverse events and routine laboratory evaluations. Global assessment of efficacy and tolerability by physician and patients was performed at the last visit. RESULTS: Using intention-to-treat analysis, all efficacy assessments demonstrated statistically significant improvements over baseline at each follow-up. 90.3% of the patients evaluated the efficacy of PBC as improved or greatly improved, and investigators rated the treatment as improved or greatly improved in 87.1% of patients. Remission was achieved in 19.3% of the patients. Tolerability was also rated highly, with 83.9% of the patients characterizing PBC treatment as good or very good, and the investigators rated the treatment as good or excellent in 87.1% of the patients. Drug related adverse events were reported in 9.7% of patients and prompted discontinuation of the study medication in 3.2% of patients. No serious adverse events were reported. CONCLUSION: These results suggest that the newly developed dosage form of piroxicam is effective and well tolerated in the treatment of patients with chronic BP. Thus, PBC, may be an important new treatment option in this condition. (Tab. 3, Fig. 3, Ref. 36.).

No intracerebral steal phenomenon in the ischemic brain following papaverine administration.

The steal phenomenon due to a vasodilator was investigated in 6 cats in which cerebral ischemia had been produced by left middle cerebral artery (MCA) occlusion. The photoelectric method was employed for continuous recording of the cerebral blood volume together with frequent determinations of the cerebral blood flow (CBF) through the ischemic cerebral tissue at the following four stages: before MCA occlusion, 2 hours after MCA occlusion before the injection of papaverine, after the injection of papaverine, and when the systemic arterial blood pressure (SABP) was adjusted non-pharmacologically to the control level using a "vasculator". The administration of the vasodilator produced conflicting results for the CBF changes in the ischemic area with a decrease in SABP as reported previously in the literature. However, when the SABP was corrected to the control level, the CBF in the ischemic region became increased in all 6 cases to above the control ischemic flow values. It is concluded that the decreased CBF in the ischemic tissue after vasodilator administration was not due to the steal phenomenon, but simply to a fall in SABP.

[Intracerebral hemorrhage in hypertensives: diagnosis, therapy and prognosis]. / Intracerebrálne krvácanie u hypertonikov: diagnóza, liecba a prognóza.

The authors analyzed 98 cases of intracerebral haemorrhage in hypertonic subjects from the aspect of the clinical course, CT findings and therapeutic results. Thirty-seven patients were treated by surgery and 61 had medicamentous treatment. The acute mortality rate in operated patients was 57% in non-operated ones 30%. The patients with haemorrhage in the putamen formed the majority of the group and had a higher mortality rate than patients with other sites of haemorrhage. The state of consciousness on admission and the size of haematomas influenced in a significant way the acute mortality rate of patients. Fifty-nine patients were followed up for an average period of 34 months. Of those 19% died and 54% attained a fair restoration of the clinical condition. Only 5% returned to work.