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.

Coordinate-based mapping--a new method in health services research.

The Finnish national hospital discharge registers from 1985 and 1988 have been analysed by the National Board of Health. Results are provided for all the 21 Finnish hospital districts and central communal organizations. The small area variation phenomenon in hospital utilization cannot be explained by demographic or epidemiological factors. Rather, the variations seem to be largely due to organizational factors. The project aims to develop a data processing system capable of handling information on one million patients rapidly and economically, and show the results in an intelligible form as a table with standard headers or as a map illustration. Maps are superior to traditional statistical tables in demonstrating regional variations in health care utilization and in mortality. Maps based on small administrative units are useful for many purposes. These maps are, however, relatively 'noisy' due to substantial random variation. Coordinate-based mapping is a method to overcome some of these difficulties. It is based on linking hospital discharge and mortality data with exact address data. The method allows mapping independent of administrative boundaries. Several examples of coordinate-based maps are given. The method is used in Finland for annual analysis of hospital use.

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.

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.

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.

Efficacy of nimodipine in the prophylaxis of migraine.

The efficacy of nimodipine in the prophylaxis of migraine was assessed in a double-blind, placebo-controlled, cross-over study carried out on 33 patients, 20 of whom suffered from classic and 13 from common migraine. Four patients dropped out, but not as a result of the side effects of the drug. The duration of drug treatment was 8 weeks. The dosage used was 30 mg four times daily. Nimodipine proved to be better than placebo, the number of migraine attacks and severity of headache showing a significant reduction. The drug was well tolerated and no marked side effects were noted. The results suggest that nimodipine is a useful new prophylactic drug for migraine, but further studies are needed before its final value can be evaluated.

Ergotamine abuse: results of ergotamine discontinuation, with special reference to the plasma concentrations.

Twenty-three patients suffering from continuous headache linked with habitual daily use of ergotamine tartrate were studied. Their headaches were classified clinically, and possible side effects of ergotamine medication, plasma levels of ergotamine, and occurrence of withdrawal symptoms after discontinuation of drug abuse were recorded. Seventeen of the patients were clinically diagnosed as suffering from "ergotamine headache", and seven of them complained of coldness in the extremities. Plasma ergotamine levels were measured by using a radioimmunoassay. In almost half of the patients the 1 h plasma levels after the daily dose were below the detection limit of the procedure (0.12 ng/ml). The duration and severity of the withdrawal symptoms did not correlate with the doses and plasma levels of ergotamine. In only 4 of the 21 patients who were followed up for 3 to 6 months did headache symptoms not improve after ergotamine withdrawal. The results indicate that even small (0.5-1.0 mg/day) doses of ergotamine tartrate taken regularly may cause continuous headache symptoms and withdrawal symptoms after discontinuation.

Relationship between plasma high-density lipoprotein cholesterol and anticonvulsant levels in epileptics.

Plasma high-density lipoprotein (HDL) cholesterol is a recognized negative risk factor for coronary heart disease. In this study, therapy with phenytoin alone, carbamazepine alone, and phenytoin in combination with phenobarbital was associated with elevated plasma HDL cholesterol concentrations. The highest HDL cholesterol levels were seen in subjects treated with the combination of phenytoin and phenobarbital. Plasma HDL cholesterol levels were proportional to the serum phenobarbital and carbamazepine concentrations. In subjects treated with phenytoin alone, low plasma HDL cholesterol levels were associated with low drug concentrations. The results suggest direct links running from the serum anticonvulsant levels to the extent of hepatic microsomal enzyme induction, and further to the plasma HDL cholesterol concentrations.

Cerebrospinal fluid protein findings in cervical syndromes classified by myelography, and in multiple sclerosis.

Determinations of cerebrospinal fluid (CSF) albumin, IgG, albumin blood brain barrier (BBB) permeability and local IgG synthesis indexes in CNS were carried out on 85 patients with various neck, shoulder and upper extremity pain syndromes. CSF was obtained by lumbar puncture in 29, and by lateral neck puncture in 56 of the patients. The patients were classified into 3 different groups according to varying severity of degenerative changes, or cavitation verified by myelography. CSF protein patterns in these patients were compared with lumbar CSF findings in 18 patients with multiple sclerosis. CSF protein changes in patients with abnormal myelographic findings were slight. Protein values were clearly more abnormal in lumbar CSF than in cervical CSF, probably due to a retardation of the CSF flow. Only 3 of 62 patients with a narrowing of the cervical spinal canal had pathological values for IgG synthesis or BBB permeability indexes. On the other hand 14 of 18 patients with multiple sclerosis had abnormal, high values for the IgG index. Thus the present results suggest that investigation of the CSF protein pattern has value in differential diagnosis between patients with multiple sclerosis and degenerative diseases of the cervical spine.

Non-invasive external regional measurement of cerebral circulation time changes in supratentorial infarctions using pertechnetate.

A method for measuring regional cerebral circulation time (rCCT) between the hemispheres using intravenous pertechnetate and a multidetector system is presented. Interhemispheric differences of rCCT instead of absolute values were selected because of the variation of pertechnetate bolus dispersion due to changes in the systemic circulation and injection technique inter-and intraindividually. Time activity curves over one minute were analyzed by a modified gamma function fitting method. The results are printed as a brain map which shows reference values and abnormal findings. Abnormal rCCT asymmetry was observed in 10 out of 77 controls (13%) and 58 out of 65 patients with cerebral infarction (89%). Within 2 weeks after a stroke shorter circulation time values on the side of the lesion than on the contralateral side were found in 5 patients. In the severe infarction cases and in the acute stages of infarction circulatory changes could be found in a great number of areas. In patients with manifest diabetes abnormal circulatory findings occurred in larger regions and in a greater number of the patients than in those without that disease. Although the luxury perfusion and diaschisis phenomena, as well as the influence of cross-over of the count rates between the hemispheres, reduce circulatory time differences, use of the present pertechnetate method allows detection of subtle regional circulatory changes in patients with brain infarction.

Serial measurements of quantitative EEG and cerebral blood flow and circulation time after brain infarction.

The quantitative EEG (QEEG), regional cerebral blood flow (rCBF) and circulation time of 17 patients were examined semisimultaneously thrice during the first 3 months after a cerebral supratentorial infarction. The EEG was quantified according to normalized slope descriptor technique in nine patients and by means of a combined period and amplitude analysis in eight patients. Intravenously injected isotopes 133Xenon and 99TcmO4 were used for blood flow and circulation time measurements. The QEEG-values improved during the whole follow-up period. Cerebral blood flow stayed low for all 3 months and did not alter during this period, while initially prolonged circulation time to some extent improved within 2 weeks remaining, however, prolonged even thereafter. A tendency for a positive correlation between QEEG and rCBF values in the infarcted hemisphere could be seen.

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 cerebral infarctions of the carotid area by an intravenous 133Xenon and 99mTechnetium method.

Quantitative determinations of regional cerebral blood flow (rCBFf, rCBFm) and volume (rCBV), transfer time (rCTT) and fast compartmental weight (Wf) were performed in 34 patients with infarctions of the carotid area by a 133Xe and 99mTc intravenous injection method. The results were compared with clinical signs and electroencephalographic (EEG) findings. A significant difference was found between the lesion side and the control side in all the parameters except rCBV. This difference increased with the severity of the infarction and age of the patients. The difference between the two sides was especially great in the patients with totally occluded internal carotid artery. A slight diaschisis could be observed in the present infarction group. An almost significant reduction on the "normal side" was seen in Wf. In order to assess the reciprocal influence of all the different blood flow parameters, the difference index (DI): Formula: (see text) was calculated, where delta i = the difference between the two sides in one parameter expressed in percent. This proved to be abnormal in 80% of the patients. The atraumatic isotope technique employed offers a good opportunity for the quantitative evaluation of hemodynamics in cerebral infarction and serves as an aid in the diagnosis of infarction.

Systemic availability of ergotamine tartrate in continuous medication.

There seems to be great individual differences in the bioavailability of ergotamine in continuous use. The great tolerance to ergotamine in some patients using the drug on a daily basis, even in high doses, may be due to the low-bioavailability of ergotamine in these subjects. This may also explain the infrequency of serious complications among migraine patients.

Systemic availability of ergotamine tartrate in healthy subjects after single and repeated oral doses.

The studies presented indicate that ergotamine tartrate taken orally in single or repeated 2 mg doses is biologically available in most of the subjects examined. The peak plasma concentration of the drug in the ng/ml range is attained at 1-2 hours. It seems probable that there is a second rise in the plasma concentrations of the drug, possibly indicating an accumulation of ergotamine or some of its immunoreactive metabolites, and this needs further evaluation.

Plasma high-density lipoprotein cholesterol in epileptics treated with various anticonvulsants.

Plasma high-density lipoprotein (HDL) cholesterol in 97 epileptics on long-term anticonvulsant therapy was investigated. Therapy with phenytoin alone or in combination with carbamazepine or phenobarbital was associated with elevated plasma HDL cholesterol levels as compared with controls. HDL cholesterol in patients treated with carbamazepine did not diverge from control values. Patients treated with phenytoin and phenobarbital in combination showed higher HDL cholesterol levels than those treated with phenytoin alone. There was an inverse correlation between the HDL cholesterol and serum triglyceride levels. The results demonstrate that high plasma HDL cholesterol might be associated with therapy involving some anticonvulsants known to be potent enzyme inducers. This suggests that the elevation of HDL cholesterol during therapy is probably related to the drug-caused enzyme induction phenomenon.

Brachial plexus and radicular neurography in relation to cortical evoked responses.

An application of somatosensory potential recording suitable for clinical neurodiagnostics is described. Evoked responses were recorded with surface electrodes at four levels between wrist and scalp: Erb's point, seventh cervical spine, inion, and the somatosensory area of the scalp. The normal latency and latency difference values based on 16 healthy subjects are presented as well as those of four examples of pathological cases with lesions at various levels in the nervous system. The method presented offers novel possibilities for solving problems of differential diagnosis, especially at the level of the brachial plexus.