[Drug clinical trials and their importance for diabetology]. / Klinické hodnocení léciv a jeho význam pro diabetologii.

The system of drug clinical trials has gradually become the basic pillar of pharmacotherapy principles denoted as evidence-based medicine. It serves, in particular, to ensure the efficacy and safety of newly introduced drugs. The first institute dealing with drugs in the territory of the current Czech Republic was founded as early as in 1918. The then drug research institute became one of the predecessors of the modern State Institute for Drug Control. The definition of drug clinical trials covers several basic factors, such as pharmacodynamics, pharmacokinetics, adverse effects, drug safety and efficacy and, in particular, testing systematicness. The clinical trial itself is carried out in four basic stages. Each of them consists of a set of studies which rationally follow up one another. In stage I, the first administration of the drug to the patient, the basic evaluated factor is the drug's safety. In stage II, pilot studies are carried out in patients, which serve to verify safety and to monitor efficacy. Before a new drug is registered, extensive clinical studies in large cohorts of patients are carried out in stage III, covering many pharmacological characteristics of the drug. The statistical evaluation of the extensive set of data thus obtained determines the quality of interpretation of the study results. The significance of negative effects (bias) can thus be reduced. The planning of a control group, randomization and clinical study blinding serves this purpose. When applying the drug clinical trial data in practical pharmacotherapy, certain limits ofclinical studies need to be taken into consideration as well. The entire system ofdrug trials will change based on certain modern methods (biotechnology, pharmacogenetics).

Simultaneous determination of nitrendipine and one of its metabolites in plasma samples by gas chromatography with electron-capture detection.

A sensitive method for GC-ECD simultaneous determination of nitrendipine and its pyridine metabolite M1 in human plasma is described. Felodipine was used as the internal standard. The plasma samples were extracted with toluene. One microlitre of the extract was injected onto the capillary column (polymethylsiloxane) and measured with electron-capture detector. The developed method showed to be linear over the range 0.25-70 for nitrendipine and 0.3-61 ng/ml for its metabolite M1 with an inter-day and intra-day precision in terms of R.S.D. lower than 8% except the concentrations near lowest limit of quantification (LLOQ) (<11% R.S.D.). The LLOQ for nitrendipine was 0.25 and 0.3 ng/ml for its metabolite, respectively. The analytical recovery was 94% for nitrendipine and 89% for its pyridine metabolite M1. This GC-ECD method was developed for being used in clinical pharmacokinetic studies.

[Use of a health insurance company database for study of theoretical exposure to hypolipidemic agents]. / Vyuzití databáze zdravotní pojist'ovny ke studii teoretické expozice hypolipidemiky.

OBJECTIVE: The objective of the investigation was to analyze theoretical exposures to hypolipidaemics in patients treated chronically with these drugs, using the database of the health insurance company. INVESTIGATED GROUP: From the database (with information on age, sex of the insured person, the number of packages and the type of hypolipidemic and year of issue of the prescription) of subjects insured at the Employees Health Insurance Skoda Mladá Boleslav comprising some 100,000 insured subjects in 1994-2000. Patients with long-term (more than one year) hypolipidaemic treatment were selected in years from 1995 to 1999. The group increased every year. In 1995 it comprised 668 cases in 1999, 2396 subjects. METHOD: The consumption of hypolipidaemics was expressed in defined daily doses (DDD). The authors investigated the ratio of chronically treated patients and the proportion of the following groups of patients according to their annual consumption in 1995-1999: group of of drug "vacation" (0 DDD) and the group with a low (< 121.7 DDD), medium (< 243.3 & > 121.7 DDD) and optimal (> 243.3 DDD) consumption of hypolipidaemics and their relationship to sex and age. For statistical ealuation software SPSS 10.1 was used. RESULTS: In the course of the investigation among the insured subjects the statin consumption increased 76 times and the consumption of fibrates 5 times. The ratio of consumption of resin derivatives and of nicotinic acid was negligible. The size of the group of subjects treated with hypolipidaemics for longer than one year increased from 0.8% in 1995 to 2.2% of the database. The average age increased from 55 to 59 years. The ratio of seniors (> or = 65 years) increased in the course of the investigation and reached 33% in 1999 of all members of the investigated group. The mean annual consumption of hypolipidaemics increased significantly as compared with 1995 and the interannual increase as compared with the previous year was statistically significant in 1997 and 1999. In 1999 it was 237 DDD/per consumer. A lower consumption was recorded in women and in seniors. Drug "vacations" were recorded in 6% of the insured subjects of the group and the frequency did not change significantly in the course of the investigation and no relationship with age and sex was found. A low exposure according to DDD was found in 20%, medium exposure in about 40% and optimal exposure in only one third of the subjects of the investigated group. CONCLUSION: The authors developed a method which makes it possible, when individual data of the health insurance company are available, to investigate the theoretical exposure to hypolipidaemics in insured subjects treated on a long-term basis with these drugs. The authors provided evidence that analysis of the database of the health insurance company can provide certain signals for further pharmacoepidemiological research and for application in a defined medical discipline. Some of the insured subjects are exposed to smaller doses than theoretically assumed. It is necessary to extend the investigation so that the results will better reflect the population of patients and prescribing physicians. Complete evaluation of cases with a low exposure from the aspect of morbidity and drug compliance will be also essential.

Determination of enzyme (angiotensin convertase) inhibitors based on enzymatic reaction followed by HPLC.

For determination of levels of plasmatic inhibitor of ACE (angiotensin convertase) a simple method was used based on a combination of enzymatic reaction followed by an HPLC determination of its product. The inhibitor (e.g. enalaprilat) was at first separated from the biological material by deproteination (methanol). Then, an aliquot of the sample was added to the reaction mixture containing a commercial ACE enzyme, its specific substrate FAPGG (N-(3-[2-furyl]acryloyl)-Phe-Gly-Gly) and buffer (Tris--HCl, pH 7.5). Degree of inhibition of the conversion of this substrate to FAP (desGlyGlyFAPGG) by the inhibitor present in the sample is related to its amount by a simple dose-response relationship. The amount of the FAP was determined by an HPLC on a RP-18 column with an acetonitril--nonylamine buffer (pH 2.4, adjusted with phosphoric acid) as a mobile phase with detection at 305 nm. Alternatively, the activity of the endogenous ACE present in the plasma was measured. The substrate FAPGG was added to the plasmatic sample containing both the inhibitor and endogenous ACE (as the sample was not deproteinized in this case) and the reaction product was determined as above. Inhibitor concentration has been obtained from a dose--response curve expressing the interaction with inhibitor with an ACE enzyme.

Bone-targeted Src SH2 inhibitors block Src cellular activity and osteoclast-mediated resorption.

Src, a nonreceptor tyrosine kinase, is an important regulator of osteoclast-mediated resorption. We have investigated whether compounds that bind to the Src SH2 domain inhibit Src activity in cells and decrease osteoclast-mediated resorption. Compounds were examined for binding to the Src SH2 domain in vitro using a fluorescence polarization binding assay. Experiments were carried out with compounds demonstrating in vitro binding activity (nmol/L range) to determine if they inhibit Src SH2 binding and Src function in cells, demonstrate blockade of Src signaling, and lack cellular toxicity. Cell-based assays included: (1) a mammalian two-hybrid assay; (2) morphological reversion and growth inhibition of cSrcY527F-transformed cells; and (3) inhibition of cortactin phosphorylation in csk-/- cells. The Src SH2 binding compounds inhibit Src activity in all three of these mechanism-based assays. The compounds described were synthesized to contain nonhydrolyzable phosphotyrosine mimics that bind to bone. These compounds were further tested and found to inhibit rabbit osteoclast-mediated resorption of dentine. These results indicate that compounds that bind to the Src SH2 domain can inhibit Src activity in cells and inhibit osteoclast-mediated resorption.

[Monitoring utilization of hypolipemic agents using an insurance company database]. / Sledování spotreby hypolipidemik pomocí databáze pojistovny.

Databases of health insurance companies can provide information on the motion of a drug in the society. The present paper examines several databases of health insurance companies and analyzes the development of the consumption of hypolipidemic agents in 1994 through 1998. So-called evaluation databases making it impossible to identify a particular patient and the prescribing physician were prepared for the evaluation. They were obtained from the VZP central health insurance office, VZP district health insurance offices in Hradec Králové and Kladno, and the Zamestnanecká pojistovna Skoda (Employees Health Insurance Company Skoda). It was not necessary to blind the data in the first cohort, in the second one it was carried out by shortening the identification numbers, and in others by introducing artificial identification codes. The consumption was expressed in DDD and in the relative representation in the group. The consumption of the principal groups of hypolipidemic agents (fibrates, statins, sequestrants of bile acids, and derivatives of nicotinic acid) and the individual medicinal substances was evaluated. Relative values of consumption were obtained by calculation to the magnitude of the denominator--the number of the insured, or the number of patients to whom a hypolipidemic agent was prescribed. The consumption was on the increase in all three databases, in four years increasing from approx. 0.4-4DDD/1000 of the insured/day to 16-24DDD/1000 of the insured/day. At the beginning, the main share in the consumption of hypolipidemic agents was represented by fibrates, approx. 90%, but in four years this share decreased to only 60%, whereas in the period under study the share of statins increased up to 30%. Databases of health insurance companies do not significantly differ in the consumption of hypolipidemic agents, which may give evidence of their validity. In the course of the study, an increase in the consumption of hypolipidemic agents, primarily statins, was found. The shift in the consumption of statins corresponds with the available information about the evidence of their therapeutic effectiveness. The average consumption per one patient does not reach 1DDD, which is a signal that probably very few patients receive long-term treatment and that new patients emerge during the year.

[Cross-sectional study of choice of drug therapy in the acute phase of treatment in acute myocardial infarct--part 1]. / Prurezová studie volby farmakoterapie v akutní fázi lécby akutního infarktu myokardu--1. cást.

INTRODUCTION: Treatment of acute myocardial infarction is undergoing changes. In the treatment of acute myocardial infarction in particular the following proved useful: thrombolysis, administration of anti-aggregating drugs, beta-blockers and inhibitors of angiotensin converting enzyme. An decisive part is played by the interval between the onset of symptoms and the beginning of hospital treatment. OBJECTIVE: To describe treatment of patients hospitalized at intensive care units for acute myocardial infarctions. Investigate differences between faculty and other hospitals. METHOD: The authors investigated by means of questionaires in a prospective study during the first three months in 1996 all patients who were hospitalized on account of acute myocardial infarction. The investigation was implemented in seven intensive care units of faculty hospitals and in nine intensive care units of hospitals and information on diagnosis, pharmacotherapy and results of therapy were assembled. During the first 24 hours of treatment more detailed information was procured. RESULTS: Antiaggregants were used in 88%, nitrates in 77.8%, thrombolytics, beta-blockers and and ACE inhibitors in ca 30% patients. Percutaneous transluminal coronary angioplasty was used in ca 7% patients. CONCLUSIONS: The authors describe treatment of the acute stage of myocardial infarction. In faculty hospitals in 1996 thrombolysis, percutaneous transluminal coronary angioplasty, beta-blockers and nitrates by the i.v. route were used more frequently.

Pharmacokinetic parameters of verapamil and its active metabolite norverapamil in patients with hepatopathy.

Verapamil (CAS 52-53-9) is a calcium channel blocker with a vasodilatatory effect. Because of its significant first-pass effect, verapamil might be advantageous in the treatment of portal hypertension. It does not produce any excessive systemic effects, provided the doses are suitably adjusted. A decision was made to examine the pharmacokinetic parameters, independent of compartmental analysis of verapamil and its active metabolite norverapamil, in patients with portal hypertension. Their biological half-lives of the terminal phase were significantly prolonged as compared with the control group. However, no statistically significant differences were found in the values of tmax and Cmax. The calculated pharmacokinetic parameters of norverapamil were not significantly different from those of verapamil, except for the tmax of norverapamil, which was significantly longer in patients suffering from portal hypertension as compared with verapamil. The ratio of areas under the plasma concentration-time curve (AUC) of verapamil and norverapamil was comparable in both groups of patients. No relationship between the changes in the pharmacokinetic parameters and the extent of hepatic insufficiency was observed.

[Actilyse (a recombinant tissue-type plasminogen activator] in the treatment of acute myocardial infarct. Comparison of the effects of Actilyse and streptokinase]. / Preparát Actilyse (rekombinacní tkánový typ aktivátoru plazminogenu) v lécbe akutního infarktu myokardu. Srovnání úcinku Actilysy a Streptokinázy.

The preparation Actilyse--a tissue plasminogen activator prepared by recombination--is an effective fibrinolytic drug. The authors recorded in a group of 33 patients reperfusion in 91%, evaluated on the basis of indirect criteria. In a group of 18 patients treated with streptokinase reperfusion was achieved in 74%. Based on changes of CK and CK-MB values--an earlier rise of values following Actilyse administration and conversely their more marked increase during subsequent sampling after streptokinase administration--it may be assumed that earlier dissolution of the thrombus in the coronary artery occurs after Actilyse administration, as compared with streptokinase. It may be thus assumed that there is also a smaller necrotic focus after Actilyse treatment, as compared with streptokinase. Early re-occlusion--according to indirect indicators--occurred in 8.6% in the Actilyse treated groups, as compared with 5.9% in the streptokinase treated group. The fibrinogen values decline in the Actilyse group to 40% and in the streptokinase group to 28%. Later enhanced new formation of fibrinogen occurs and the fibrinogen values rise to 160% in the Actilyse treated group and to 250% of the initial value in the streptokinase treated group. The elevated fibrinogen value, as compared with the baseline value, persists for the 12 days of the follow-up. No severe spontaneous haemorrhage was recorded, haemorrhagic manifestations were associated with blood sampling and i.v. administration of drugs only. The necessity to administer blood was due to a complication during puncture of the subclavian vein in one patient.(ABSTRACT TRUNCATED AT 250 WORDS)

High-performance liquid chromatographic determination of ambroxol in human plasma.

Ambroxol has been determined in biological fluids using a rapid and sensitive high-performance liquid chromatographic method. The samples prepared from plasma by liquid-liquid extraction were analysed on reversed-phase silica gel by competing-ion chromatography with ultraviolet detection. The method was applied to the determination of ambroxol levels in twelve healthy volunteers after oral administration of 90 mg of ambroxol in tablets of Mucosolvan and Ambrosan.

[Prostanoids and leukotrienes in ophthalmology. I. Basic biochemistry and physiology of prostanoids and leukotrienes]. / Prostanoidy a leukotrieny v ocním lékarství. I. Základy biochemie a fyziologie prostanoidu a leukotrienu.

The authors give a brief account of hitherto assembled knowledge on the biochemistry and physiology of prostanoids and leucotrienes. They describe the history of investigations of these substances, their properties and patterns of synthesis. The authors evaluate possibilities of the pharmacotherapeutic use of inhibitors of prostanoid and leucotriene synthesis.

[Prostanoids and leukotrienes in ophthalmology. II. Role of prostanoids and leukotrienes in the physiology and pathophysiology of the eye]. / Prostanoidy a leukotrieny v ocním lékarství. II. Ucast prostanoidu a leukotrienu ve fyziologii a patofyziologii oka.

The authors give an account on the development and contemporary knowledge regarding the participation of prostanoids and leukotrienes in physiological and pathophysiological processes of the eye. According to many data in the literature of all intraocular tissues of the human eye the greatest prostaglandin production was found in the anterior segment of the choroid. The authors describe the role played by these substances in the pathogenesis of inflammations, their importance in the regulation of intraocular pressure and in the development of cystoid macular oedema.

[Prostanoids and leukotrienes in ophthalmology. III. Results of a clinical study of local administration of indomethacin in preoperative and postoperative care]. / Prostanoidy a leukotrieny v ocním lékarství. III. Výsledky klinického sledování lokálního podávání indometacinu v predoperacní a pooperacní péci.

The authors submit results of the clinical investigation involving indomethacin administration during preoperative and postoperative care of patients with primary glaucoma who were submitted to trabeculectomy. The investigation was made by the method of a double blind trial. Indomethacin 0.5% eye drops or placebo were administered on the day prior to operation to the 10th day after operation, three times a day. During the final comparison of the two groups after indomethacin a reduction of the number of postoperative complications was observed, as well as a shorter hospitalization period, and the result of the filtering operation was not affected.

Increased glycation and pigmentation of collagen in aged and young parabiotic rats and mice.

Changes of non-enzymatic collagen glycosylation were followed in 2- and 24-month-old rats and mice and in parabiotic animals of the same age. With advancing age increased glycation of collagen was observed in both old male Wistar rats and white mice. Further it was demonstrated that both aortal and skin collagen of young animals is rapidly non-enzymatically glycosylated in the common milieu created by parabiotic animals and the proportion of non-enzymatically incorporated glucose approaches in the young counterparts the level found in old individuals. Similar trends as with non-enzymatic glycosylation were found with a fluorescent (370/440 nm) product present in both categories of collagen preparations. This fluorescence was higher in old animals and was considerably increased in the young counterpart of the parabiotic couple 6 weeks after operation. The nature of the fluorescent product appears different from pyridinoline and remains to be elucidated.

The effect of low protein-high dextrin diet and subsequent food restriction upon life prolongation in Fischer 344 male rats.

Fischer 344 rats fed low protein-high dextrin diet exhibit a higher median (but not 10th percentile) survival as compared to controls. The effect of this diet appears already if the diet is administered between 6 weeks and 6 months of age; after this treatment median survival of experimental animals is increased by 96 days while the 10th percentile is not different from standard diet-fed controls. Further treatment of animals with the same diet has minimum effect as animals that lived on this regimen throughout the whole life exhibited a median lifespan increase by 120 days and increase in the 10th percentile by 41 days. However, if such animals at the age of 6 months are transferred to a restricted (60%) food intake regimen (control diet, not carbohydrate enriched) a further increase in median and 10th percentile lifespan prolongation can be observed reaching +328 and +396 days respectively as compared to controls. The effects of this early feeding (6 weeks to 6 months) with a low protein-high carbohydrate diet available ad libitum and the food restricted regimen (standard diet 60% controls) fed from the age 6 months onwards are additive, the final results being identical to those obtained if the animals were kept on the 60% food restricted intake throughout the whole life. The fact that animals fed the low protein-high carbohydrate diet and those kept on 60% standard diet food restriction had different survival though they were equal in daily (identical) protein intake is emphasized.

Determination of fatty acids as phenacyl esters in rat adipose tissue and blood vessel walls by high-performance liquid chromatography.

Twenty-two biologically relevant (6:0-22:6) saturated, monounsaturated and polyunsaturated fatty acids were separated by reversed-phase high-performance liquid chromatography after derivatization with phenacyl bromide. An optimal resolution of the critical combinations linolenic-myristic, docosahexaenoic-palmitoleic-arachidonic and palmitic-oleic acids and cis and trans isomers of octadecenoic (n9) and octadecadienoic (n9, 12) acids was achieved by continuous gradient elution with methanol-acetonitrile-water. Elution of mixtures of 6:0-22:1 fatty acids was completed within 80 min at a flow-rate of 1 ml/min. By the use of UV detection at 242 nm the detection limits for short- and long-chain fatty acids were found to be about 0.8 and 12 ng per injection, respectively. Linearity was tested up to 100 ng. The method was applied to the determination of fatty acids in rat adipose tissue and blood vessel walls of animals fed hydrogenated fat diets. The results are comparable to those obtained by gas chromatography and surpass the latter for the resolution of oleic and elaidic acids.

Collagen in the aortae of spontaneously hypertensive (SHR) rats.

A biphasic pattern of collagen biosynthesis was found in the aortae of spontaneously hypertensive (SHR) rats; the time course of the rate of biosynthesis is similar to that described in the heart by Sen and Bumpus. In comparison to age-matched controls, collagen biosynthesis is elevated in the SHR rats, diminishes during the first fourteen weeks and rises again at the stage of established hypertension. In the period of established hypertension, the increased rate of collagen biosynthesis was associated with a pronounced rise of the collagen type I to type III ratio. On the other hand, in the pre-hypertensive stage, the proportion of collagen type III clearly exceeds the proportion of collagen type I in SHR rats.