Nonspecific luminometric assay for monitoring protein adsorption efficiency and coverage on nanoparticles.

Nonspecific assays utilizing time-resolved luminescence resonance energy transfer (TR-LRET) are developed for two applications: to monitor protein adsorption efficiency and to assess the degree of surface coverage on the solid phase. We successfully measure the adsorption efficiency of non-sedimenting nanoparticles since this has been notoriously difficult to determine. Monitoring of the protein adsorption on nanoparticles does not require the nanoparticles with the adsorbed protein to be washed and it is based on the competitive adsorption between the non-adsorbed analyte protein and the acceptor-labeled protein to donor europium(iii) polystyrene nanoparticles. The application for assessing the degree of surface coverage is performed with the final coated and washed analyte nanoparticles and it requires no fluorescent labeling of the studied protein. This application utilizes the competitive adsorption of the acceptor-labeled protein on analyte nanoparticles partly covered with protein and donor europium(iii) polystyrene nanoparticles. The developed methods detect either non-adsorbed protein or uncovered nanoparticle surface, not the proteins adsorbed on the nanoparticles. This is not achievable with the traditional total protein quantification assays applied for monitoring protein adsorption since both non-adsorbed and adsorbed protein are detected and their separation is required. Thus, the developed application for monitoring protein adsorption is user-friendly, requires no centrifugal instrumentation, and is applicable also for small nanoparticles requiring ultracentrifugation. No special expertise or investment in costly instruments is required compared to the existing methods, such as spectroscopic techniques, isothermal titration calorimetry, and surface plasmon resonance. The application for assessing the degree of surface coverage is compared to a reference literature method that comprised the analysis of adsorbed fluorescently labeled protein. The saturation reached at similar protein concentrations showing the reliability of the assay. Our results suggest that the developed applications could be exploited as rapid tools for protein adsorption studies on nanoparticles and for quality control and characterization of the coating processes.

Neuropsychologic outcome after open-heart surgery.

A neuropsychologic (NP) study was carried out on 49 patients who had had cardiac valvular replacement to investigate the determinants of postoperative outcome. The results were assessed together with operative data and with neurologic and quantitative EEG (QEEG) findings. Of the operative variables, perfusion time and unexpected intraoperative events were the most important factors leading to postoperative NP impairment. Clinical neurologic outcome correlated positively with NP changes. Differences between various cardiologic and age groups were found in the postoperative NP findings. Changes in frequency in QEEG reflected the NP changes more reliably than did amplitude. Significantly one of the tests, a modification of the Stroop color test, was found to be prognostically important, suggesting that it might be possible to construct test batteries of value in predicting high operative risk. The results show that multiparameter investigation using NP testing together with clinical and QEEG follow-up is useful in the assessment of cerebral disorders attributable to open-heart surgery.

Evaluation of the jitter phenomenon in myasthenic patients and their relatives.

Single fiber electromyography with jitter measurements and blocking evaluation was used for investigating 23 myasthenic patients, their 29 healthy relatives, coming from 10 families, and a control group of 10 subjects. Blocking was never seen in the healthy controls, and the jitter averaged some 30 microsec. Blocking was present in the myasthenic patients in 25.4% of the recorded potential pairs and there was a pathological jitter, which often extended over a few hundred microsec. The records of ten healthy relatives of patients were suggestive of slight but unquestionable abnormalities of neuromuscular transmission, viz. blocking and a jitter of over 60 microsec or more. The results demonstrate subclinical derangements of neuromuscular transmission in families of myasthenic patients, which points to a familial factor as involved in the pathomechanism of the disease.

Multiple-dose pharmacokinetic study with a slow-release carbamazepine preparation.

The pharmacokinetics, clinical efficacy and side effects of carbamazepine (CBZ) in the steady-state condition were studied using a slow-release preparation (SR), Neurotol Slow, and a conventional preparation (C), Tegretol. Eighteen adult epileptic patients under CBZ therapy were evaluated in this single-blind, randomized cross-over study. The previous daily CBZ dose was kept unchanged and divided into 2 daily doses during two 2 week study periods. At the end of each period blood samples were drawn at frequent intervals for 12 h after the administration of the morning CBZ dose. Serum concentrations of unchanged CBZ and its main metabolite, carbamazepine-10,11-epoxide (CBZE), were determined by HPLC. Peak concentrations of CBZ and CBZE were significantly lower, and the time-lapse before CBZ reached its peak was significantly longer during SR treatment. The fluctuations in serum CBZ and CBZE were significantly lower during SR treatment. There was no significant difference in bioavailability between the 2 preparations. The number of epileptic seizures was 31 during SR and 57 during C treatment. Side effects were more common during C treatment. The occurrence of dizziness was significantly lower with SR treatment than with C treatment. We conclude that greater stability in serum CBZ and CBZE concentrations can be obtained by using an SR of CBZ, without reducing the bioavailability of the drug.

Relevance of prostaglandins in migraine.

Prostaglandins (PG), particularly PGE, may be linked to the pathophysiology of migraine in several important ways. PGE1 may "simulate" a migraine attack in healthy volunteers. PGE may be elevated in patients with migraine. In animal experiments and in human infusions, PGEs cause vasodilation and hyperalgesia, both typical reactions of inflammation. The view that vascular headache is an "inflammatory reaction" allows the best concept concerning the local role of PGs and the effectiveness of PG-inhibitors in the treatment of migraine. The local role of PGs may provide a common denominator in several hormonal, neural and other influences on vessels. The common triggers of a migraine attack like menstruation, alcohol and stress influence the PG-system and even the dietary reactions, hormonal influences, sleep and reserpine have some connections with the PG-system. A local role for PGs does not diminish the importance of other pathophysiological mechanisms operating during an attack. On the contrary, PGs may fill in gaps in our understanding of how the overt pain of attacks is produced.

Social aspects in myasthenia gravis.

The myasthenics in Finland (n = 240) have been registered and treated in one center for more than 10 years. Of this material, an investigation was performed of their medico-social state as of 1 January, 1975. The study comprised 88 per cent (210) of the patients. In the working age (16-64 years) were 181 patients. Compared to the total Finnish population, the myasthenic patients lived more often in urban districts, had had more intermediate-school and university--but less vocational-school education, and belong as a whole to "higher" social classes. The severity and the variability of the disease naturally influenced the disability. A change from severe to slight symptoms occurred in 38 per cent, and 12 per cent of the myasthenics were in complete remission (2/3 of whom had had severe symptoms). One third (72) got a full pension because of myasthenia, and about one tenth (25) because of some other reason. Of these who got a full pension for myasthenia, 7 per cent were in complete remission without any myasthenic symptoms. The influence of thymectomy on the degree of disability was impressive, since more than 50 per cent of disabled myasthenic patients returned to work thereafter. Thus, because of the unpredictable, but on the long term quite favourable course, a full pension should not be prescribed early (during the first 5 years) of the disease. An active treatment may also change the outlook for even the most severely disabled patients.

Efficacy of nimodipine in comparison with pizotifen in the prophylaxis of migraine.

The efficacy of nimodipine in comparison with that of pizotifen was assessed in the prophylaxis of migraine in a double-blind cross-over study, in which a double-dummy technique was also utilized. The study was carried out on 43 migraine patients, of whom 15 had classic and 28 had common migraine. A 4-week run-in placebo period preceded the drug treatments, the drug treatments lasted 12 weeks, and there was a washout placebo period of 4 weeks between nimodipine and pizotifen treatments. The dosages used were 40 mg three times daily for nimodipine and 0.5 mg three times daily for pizotifen. Both nimodipine and pizotifen proved to be better than placebo, the number of migraine attacks showing a significant reduction. There was no difference between nimodipine and pizotifen in antimigrainous efficacy, but there were fewer side effects during the nimodipine period. The results suggest that nimodipine is an effective drug for the prophylaxis of migraine, with few side effects and therapeutic efficacy equal to that of pizotifen.