Fentanyl analogs: structure-activity-relationship study

Fentanyl is the prototype of the 4-anilidopiperidine class of synthetic opioid analgesics. This study was aimed to review the structure-activity-relationship (SAR) of fentanyl analogs substituted in the position 3, or 4 of the piperidine ring. Pharmacological results show that the groups in position 3 of the piperidine ring, which are larger than methyl, severely reduce the analgesic potency compared to fentanyl. It is likely that the steric factor alone (i.e. voluminosity of the group and cis/trans isomerism), rather than the polarity and/or chemical reactivity, plays a crucial role in the analgesic potency of this series. Although the duration of action, in general, does not depend on the stereochemistry, longer action of the most potent 3-alkyl fentanyl analogs such as cis-3-methyl- and cis-3-ethyl fentanyl, is more likely influenced by pharmacodynamic, rather than pharmacokinetic variables. Also, it is possible that the introduction of a functional group such as 3-carbomethoxy reduces the duration of action by altering pharmacokinetic properties. SAR findings obtained by evaluating the neurotoxic effects of fentanyl analogs substituted in the position 3 of the piperidine ring parallel the SAR findings on analgesia in regard to potency and duration of action. This might suggest that similar receptors are involved in producing both antinociceptive and neurotoxic effects of these drugs. It appears that both the potency and the duration of action in the series of fentanyl analogs substituted in position 4 of the piperidine ring is influenced only by the steric requirement and not by the chemical nature of the substituent.

Histopathology of chronic hepatitis C in relation to virus genotype

BACKGROUND/AIM

The natural history of hepatitis C virus (HCV) infection is variable and the factors determining the course of the illness are unclear. There are geographical variations in the distribution of different HCV genotypes, and some of them are related to the specific infection routes. Regarding our country, the dominant genotype is genotype 1b. It is unclear and still remains a question whether the distinct histopathological manifestations are related to the particular genotypes of HCV. Thus, the aim of this study was to determine whether the distinct histopathological manifestations of HCV infection might be in relation to the individual virus genotype.

METHODS

In this study we examined 126 patients with chronic HCV infection regarding the histopathological features, demographic data, and virus genotype. The observed groups of patients were predominantly infected with HCV genotypes 1b and 3a.

RESULTS

In this study we found that the patients infected with HCV genotype 1b had more frequently moderate or severe necroinflammatory activity of the disease, significantly higher grading score as compared with other genotypes (p < 0.0001). A higher degree of fibrosis was, also, more common in the patients infected with genotype 1b of HCV as compared with other genotypes (p < 0.05). There were no significant correlations between the necroinflammatory activity of the disease and the stage of fibrosis in 1b, 4 and mixed genotypes.

CONCLUSION

The present data support the hypothesis that distinct genotypes of HCV are associated with the particular histopathological manifestation of the disease.

Single-dose intravenous simvastatin treatment attenuates renal injury in an experimental model of ischemia-reperfusion in the rat

The effect of acute pretreatment with a single dose of simvastatin (1 mg/kg, i.v.; 30 min before ischemia) on renal dysfunction caused by ischemia-reperfusion (I/R) injury in the rat was investigated. I/R injury was induced by clamping both renal vascular pedicles for 45 min, followed by 4 h of reperfusion with saline (2 ml/kg per hour). Simvastatin significantly improved both parameters of glomerular and tubular dysfunction (e.g., creatinine levels and fractional excretion of Na(+), respectively) and especially improved the histological score, compared to control I/R-injured rats treated with saline or 10% DMSO only.

Homocysteine serum levels and MTHFR C677T genotype in patients with Parkinson's disease, with and without levodopa therapy

Both methylenetetrahydrofolate (MTHFR) C677T genotype and levodopa treatment may give rise to elevated serum homocysteine levels in parkinsonian patients. We aimed to clarify the interplay of these factors in pathogenesis of Parkinson's disease (PD)-related hyperhomocysteinemia. Total serum levels of homocysteine (tHcy) and MTHFR C677T genotype were investigated in levodopa-treated and -untreated parkinsonian ("de novo") patients, as well as in control healthy subjects matched by age and gender (N=83, 30 and 53, respectively). MTHFR C677T genotypes were equally distributed in PD patients and control subjects, the T allele homozygosity being observed in app. 12-17% cases. tHcy concentrations were significantly higher in both levodopa-treated and -untreated PD patients than in control subjects, and in TT homozygotes than in CT or CC genotype carriers. tHcy levels significantly correlated with the duration of the disease in PD treated patients only, reaching the maximum after 3-6 years. However, there was no correlation between tHcy levels and total daily intake of levodopa in the same group of PD patients. In conclusion, MTHFR C677T genotype is a significant factor for hyperhomocysteinemia in patients with PD, levodopa-untreated and probably even more in levodopa-treated PD patients.

[Effects of new nitric oxide synthase inhibitors on spontaneous locomotor activity]

INTRODUCTION

New nitric oxide synthase (NOS) inhibitors: 3-bromo-7-nitroindazole (3-Br-7-NI), 1-(2-trifluoromethylphenyl) imidazole (TRIM), S-methyl-L-thiocitrulline (S-Me-TC) and 7-nitroindazole (7-NI) reduce spontaneous locomotor activity in mice.

MATERIAL AND METHODS

In order to elucidate central effects of NOS inhibitors on locomotor activity, the influence of 7-NI on electroencephalographic (EEG) power spectrum in rats was investigated.

RESULTS

7-NI reduced the EEG power density in all frequency bands in rats, suggesting a depression of the central neuronal activity. The electrophysiologic power was most reduced in the range of 7-9 Hz of the rhythmic slow activity (theta rhythm), which is in accordance with decreased locomotor activity observed following administration of NOS inhibitors.

CONCLUSION

The present results indicate that nitric oxide exerts an excitatory effect on central neuronal structures involved in regulation of locomotion.

[Nitric oxide, neurodegeneration, and Parkinson's disease]

<zakljucak> Brojni rezultati velikih studija pokazuju znacajnu ulogu NO u kaskadi dogadjaja koji dovode do smrti dopaminergickih neurona. Zna se da MPTP uzrokuje neurotoksicnost putem NO sintetisanog pomocu nNOS, ostecujuci primarno dopaminergicka vlakna i zavrsetke u strijatumu, dok NO stvoren uz pomoc iNOS deluje prvenstveno na tela dopaminergickih neurona u pars compacta substantia nigra. Ostecenje uzrokovano NO iz nNOS moze sluziti kao katalizator aktivacije iNOS i glioze. Slican sled dogadjaja moze se primeniti na ostecenje dopaminergickih neurona kod ljudi, bilo usled idiopatske PB ili usled intoksikacije MPTP. Znacaj ovih otkrica je ne samo u osvetljavanju cinioca koji ucestvuju u progresiji neurodegeneracije i PB vec i u upucivanju na nove terapijske mogucnosti.

Pattern of utilization of benzodiazepines in patients with hypertension: A pilot study

Background/Aim. The analysis of drug prescribing in general practice in Serbia showed that the use of benzodiazepines is most frequently associated with hypertension. The aim of this study was to establish the correlation of the characteristics of patients with hypertension to antihypertensive drug therapy, and the intake of benzodiazepines. Methods. A special questionnaire was used for interviewing the patients (n = 171) chronically treated for hypertenson. Statistical tests used were ?2-test and Student's t-test. Results. No differences were noted in terms of age, gender, education, body weight, smoking habits and blood pressure (155?4.9/100?2.7 mmHg vs. 160?2.2/105?3.7 mmHg), between the group I (antihypertensive drugs+benzodiazepines: n = 79), and the group II (antihypertensives only: n = 92). The patients taking benzodiazepines received a lower number of different antihypertensive drugs (2.3?0.09 vs. 2.7?0.10; p < 0.01), but the total antihypertensive drug load was significantly greater than in the group II (2.6?0.10 vs. 1.9?0.15 defined daily doses (DDD)/patient/day; p < 0.01). Benzodiazepines were taken for anxiety (62%) and hypertension (21%), rarely for insomnia, mostly once a day, at bedtime. About half the patients took benzodiazepines regularly for months or years aware of the risk for addiction. Diazepam was used by 82% of the patients. The average daily exposure to benzodiazepines was 0.45?0.05 DDD/patient/day. The drug was bought without prescription in 25% of the patients, and without consulting a physician in 12% of them. Conclusion. The study confirmed a close association of hypertension with the use of benzodiazepines. The frequent use of benzodiazepines in the patients with hypertension might be caused by an inadequate response to antihypertensive drug therapy, besides anxiety and insomnia. The therapeutic efficacy of a long-term use of low doses of benzodiazepines in hypertension requires further investigation.

Chronic hepatitis C virus infection: Is there a correlation between HCV genotypes and the level of viremia?

Introduction. Hepatitis C virus (HCV) RNA status and HCV genotypes have become extremely important for exact diagnosis, prognosis, duration of treatment and monitoring of antiviral therapy of chronic HCV infection. Material and methods. For the purpose of precise and objective assessment of virologic analyses, such as the determination of the number of virus copies and virus genotypes, 110 patients with chronic HCV infection were tested. Genotyping of HCV isolates and HCV RNA quantification were performed by using the PCR method. Genotype lb infection was verified in 49.1% of patients, genotype 3a infection was found in 28.2%, genotype 4 in 9.1%, genotype 2 in 4.5%, while mixed genotype infections were diagnosed in 9.1% of cases. Results. Patients infected by genotype lb had significantly higher serum HCV RNA level in relation to patients infected by other genotypes (p<0.05). Over 70% of patients infected by genotype lb had more than 2xl06 virus copies in 1 ml of blood, while in genotypes 2, 3a and 4, the percentage was 40%, 38.5% and 30%, respectively. Male patients had approximately 7.7x10.6 virus copies in 1 ml of blood, which was significantly higher in comparison with female patients (2.3xl06 copies/ml; p<0.05). Conclusion. Our results are in concordance with the results of other authors reporting that genotype lb is predominant in Europe, as well as significantly higher incidence of viremia in patients with genotype lb infection in relation to other HCV genotypes. Based on these results, we can conclude that our patients, most commonly, present with severe clinical course of chronic HCV infection and require longer treatment (48 weeks), which causes economic problems. .

Treatment of anicteric acute hepatitis C with peginterferon alpha-2a plus ribavirin

BACKGROUND

Hepatitis C virus (HCV) infection is the most frequent cause of chronic hepatitis, cirrhosis, and hepatocellular carcinoma in the world. Acute hepatitis C is the most commonly asymptomatic liver disease with the development of chronic HCV infection in the majority of infected patients. Studies of the natural history of HCV infection suggest that only 15-30% of patients with acute infection recover spontaneously. Others, up to 85% of the infected patients develop chronic hepatitis C. Acute hepatitis C is so uncommon and with the unpredictable occurrence, and of the low frequency, that it is difficult to determine the optimal treatment of this disease. There have been many randomized, controlled trials of the therapy in patients with chronic hepatitis C, but none of an adequate size or rigor in patients with acute hepatitis C. Therefore, the causal treatment of patients with acute hepatitis C aimed at the prevention of chronic liver disease is necessary.

CASE REPORT

We have treated a patient with anicteric form of acute hepatitis C after a three-month outpatient follow-up using a combined therapy: pegylated interferon-alpha 2a, 180 microg, subcutaneously, once a week plus ribavirin 1000 mg orally once a day. The treatment lasted 24 weeks. Stable biochemical and virological response was achieved both at the end of the treatment and 6 months after the completion of the therapy.

CONCLUSION

We believe that the above mentioned might be one of the approaches to the treatment of acute hepatitis C. However, further prospective studies with significantly larger number of patients are necessary for the definite conclusions about the treatment of HCV infections.

Suicide by intravenous injection of rocuronium-bromide: Case report

Suicides by intravenous injection of an overdose of medicaments are uncommon. In this paper, we present the case of a suicide by rocuronium-bromide injection in combination with an oral overdose of metoprolol. Unfortunately, in Belgrade, there is no toxicological laboratory capable of detecting rocuronium. The interpretation of autopsy and toxicological data in this case was made difficult due to the extreme putrefaction of the body of the deceased. So, by forensic investigation, the case was solved indirectly, through circumstantial evidence: an empty ampoule of rocuronium found near the body, as well as a plastic syringe and cloth-bandage found in the left hand of the deceased.

NG-Nitro-L-arginine Methyl Ester-Induced Potentiaton of the Effect of Aminophylline on Rat Diaphragm: the Role of Extracellular Calcium

The role of extracellular calcium in the interaction between intracellular cAMP and nitric oxide (NO)/cGMP on the contractility of rat diaphragm pretreated with cumulative concentrations of aminophylline (0.36 - 3.60 mM) was investigated. In a Ca2+-free medium, NG-nitro-L-arginine methyl ester (L-NAME) (1 and 3 mM) depressed tension developed (Td) and also aminophylline-induced potentiation of Td in a concentration-dependent manner. Verapamil (2.5 microM) or nicardipine (20 microM) significantly antagonized the potentiating effect of L-NAME on Td in a calcium-containing medium. However, in the presence of verapamil or nicardipine, L-NAME still produced statistically significant potentiation of the cumulative concentrations of aminophylline (0.36 - 3.60 mM), given in the second series.

Psychiatric adverse effects induced by recombinant interferon alfa in patients with chronic hepatitis C

Introduction Hepatitis C virus infection is a slowly progressive chronic disease and the most common cause of chronic liver disease. Presently, interferon alfa based therapies, with or without ribavirin, are standard treatment for chronic hepatitis C virus infection. The most troublesome psychiatric side effects of interferon therapy in our patients are: insomnia, irritability, anxiety, mood changes, short temper, emotional and affective lability, impaired cognitive function, apathy, loss of motivation and the most serious depression with or without suicidal ideas. Material and methods In our study we treated 82 patients chronically infected with HCV divided into 3 groups: the first group of 31 patients (20 male and 11 female) received IFN-alfa in standard doses of 3 MU three times a week (t.i.w) during 24 weeks; the second group of 36 patients (25 male and 11 female) received IFN-alfa, 3 MU t.i.w plus ribavirin 1000-1200 mg per day during 24 weeks; the third group of 15 patients (11 male and 4 female) received IFN-alfa, 3 MU t.i.w plus ribavirin 1000-1200 mg per day during 48 weeks. The follow-up period after therapy in all groups lasted 24 weeks. Results During treatment, we observed at least one psychiatric side effect in 21 (26%) patients: insomnia in 11 (13%), emotional and affective lability in 9 (11%), anxiety, irritability and short temper in 8 (10%), impaired cognitive function in 7 (8%) apathia and loss of motivation in 6 (7%) treated patients. Depression, the most serious side effect, was established in 8 (10%) patients. All of these side effects were observed during later stages of treatment (between 5th and 22nd weeks of treatment). The incidence of all psychiatric side effects was significantly higher in women than in men (p < 0,01). We observed higher prevalence of depression among patients with history of alcohol and drug abuse. Treatment was temporarily discontinued (from 2 to 4 weeks) in all patients with depression, but it was not permanently discontinuated in any patient due to psychiatric side effects. Conclusion Interferon causes psychiatric disorders that are usually mild and reversible. They disappear either spontaneously, while patients are still receiving therapy or after temporary cessation of interferon alfa therapy. .

NG-nitro-L-arginine methyl ester potentiates the effect of aminophylline on the isolated rat hemidiaphragm

The effects of different concentrations of N(G)-nitro-L-arginine methyl ester (L-NAME) (0.3, 1, 3, and 10 mM), a non-selective inhibitor of NOS, on the effect of aminophylline on the isometric contraction of the isolated rat hemidiaphragm were investigated. The muscle contractions were induced by direct subtetanic electrical stimulation. Aminophylline (0.36 - 3.60 mM) produced a typical concentration-dependent increase in both parameters of the isometric contraction: tension developed (Td) and the maximum rate of rise of tension (dT/dt max). The second series of additions of aminophylline produced a more pronounced effect. L-NAME (0.3, 1, 3, and 10 mM, 30 min of incubation without stimulation) itself did not change Td and dT/dt max. However, L-NAME (1, 3, and 10 mM) produced a statistically significant potentiation of the effect of aminophylline on Td and dT/dt max.

[Nitric oxide and lung diseases]

INTRODUCTION

All three isoforms of nitric oxide synthase (NOS) are identified within various tissues of the respiratory system.

ISOFORMS OF NOS

Under physiological conditions, small amounts of NO, produced by constitutive isoforms of NOS, appear to be important in regulation of basal pulmonary vascular tone and in mediating transition from fetal to neonatal circulation; also, NO exerts antiinflammatory actions, and modulates the respiratory smooth muscle tone. NO AND RESPIRATORY TRACT DISEASES: Under pathological conditions, inducible NOS-derived NO may produce lung damage. In addition, increased or decreased production of NO is found in chronic obstructive pulmonary disease, cystic fibrosis, asthma and related inflammatory disorders, and exhaled NO level measurement is a useful tool in diagnostics of respiratory disorders.

CONCLUSION

It has been shown that NO modulates contractility of the isolated diaphragm, and there are important interactions between NOS inhibitors and drugs for respiratory disorders (e.g. aminophylline).

[Antibiotic resistance]

INTRODUCTION

After six decades of antibiotic use, the prevalence of antibiotic-resistant bacteria is increasing, and organisms resistant to almost all antibiotics have been identified.

ANTIBIOTIC RESISTANCE

It is important to understand why antibiotic resistance develops, in order to design strategies for its prevention. Factors that promote antibiotic resistance in community and hospital settings are: antibiotic selective pressure, prolonged antibiotic treatment, inadequate doses, prior use of a less effective drug of the same antibiotic class, protected sites or foreign bodies, and poor infection control practice. The best available ways to decrease and control antibiotic resistance are: rational use of antibiotics (e.g. appropriate selection of drug, dose, duration of treatment), good infection control procedures (hygienic practice and isolation), as well as local, national and global surveillance networks for monitoring dissemination of antimicrobial resistance and detection of new resistance mechanisms.

CONCLUSION

Clinical guidelines, direct education, and regular reports on antibiograms may contribute to more prudent use of antibiotics. Overall, the problem of antibiotic resistance is global. However, measures need to be taken at an individual, institutional, and ultimately at national healthcare level.