Quantitative in vivo and in vitro sex differences in artemisinin metabolism in rat

1. The pharmacokinetics of the antimalarial compound artemisinin were compared in the male and female Sprague-Dawley rat after single dose i.v. (20 mg.kg) or i.p. (50 mg.kg) administration of an emulsion formulation. 2. Plasma clearance of artemisinin was 12.0 (95% confidence interval: 10.4, 13.0) l.h. kg in the male rat and 10.6 (95% CI: 7.5, 15.0) l.h. kg in the female rat suggesting high hepatic extraction in combination with erythrocyte uptake or clearance. Artemisinin half-life was 0.5 h after both routes of administration in both sexes. Values for plasma clearance and half-lives did not statistically differ between the sexes. 3. After i.p. administration artemisinin AUCs were 2-fold higher in the female compared with male rat (p 0.001). Artemisinin disappearance was 3.9-fold greater in microsomes from male compared with female livers and it was inhibited in male microsomes by goat or rabbit serum containing antibodies against CYP2C11 and CYP3A2 but not CYP2B1 or CYP2E1. 4. The unbound fraction of artemisinin in plasma was lower (p 0.001) in plasma obtained from the male (8.8 2.0%) compared with the female rat (11.7 2.2%). 5. The possibility of a marked sex difference, dependent on the route of administration, has to be taken into account in the design and interpretation of toxicological studies of artemisinin in this species.     

Interindividual variability in metabolic activation in humans in vivo

In assessing interindividual variability in metabolic activation, the toxic metabolite is often too unstable for conventional analysis. Possible alternatives include a stable product of the reactive metabolite e.g. cysteinyl derivatives of N-acetyl-4-benzoquinoneimine, the toxic metabolite of paracetamol, adducts with DNA or protein, and indirect measurement of the activity of the enzyme(s) producing the active metabolite. An example of the last approach is the use of furafylline, a highly specific inhibitor of human CYP1A2, to determine the extent of the metabolic activation of the cooked food mutagens PhIP and MeIQx. The extent of inhibition, determined from levels of unchanged amine in urine, is an indirect measure of the activity of the activation pathway. Further refinement of this approach, allied to improved measures of the biological process of interest should prove of value in evaluating interindividual variability and its role in the risk assessment process.     

Quantitative in vivo and in vitro sex differences in artemisinin metabolism in rat

1. The pharmacokinetics of the antimalarial compound artemisinin were compared in the male and female Sprague-Dawley rat after single dose i.v. (20 mg x kg(-1)) or i.p. (50 mg x kg(-1)) administration of an emulsion formulation. 2. Plasma clearance of artemisinin was 12.0 (95% confidence interval: 10.4, 13.0) 1 x h(-1) x kg(-1) in the male rat and 10.6 (95% CI: 7.5, 15.0) 1 x h(-1) x kg(-1) in the female rat suggesting high hepatic extraction in combination with erythrocyte uptake or clearance. Artemisinin half-life was approximately 0.5 h after both routes of administration in both sexes. Values for plasma clearance and half-lives did not statistically differ between the sexes. 3. After i.p. administration artemisinin AUCs were 2-fold higher in the female compared with male rat (p < 0.001). Artemisinin disappearance was 3.9-fold greater in microsomes from male compared with female livers and it was inhibited in male microsomes by goat or rabbit serum containing antibodies against CYP2C11 and CYP3A2 but not CYP2B1 or CYP2E1. 4. The unbound fraction of artemisinin in plasma was lower (p < 0.001) in plasma obtained from the male (8.8 +/- 2.0%) compared with the female rat (11.7 +/- 2.2%). 5. The possibility of a marked sex difference, dependent on the route of administration, has to be taken into account in the design and interpretation of toxicological studies of artemisinin in this species.     

Theophylline kinetics in peripheral tissues in vivo in humans

Several biochemical and cellular effects have been described for methylxanthines under in vitro conditions. However, it is unknown, whether threshold concentrations required to exert these effects are attained in target tissues in vivo. We therefore employed the microdialysis technique for measuring theophylline concentrations in peripheral tissues under in vivo conditions.Following in vitro and in vivo calibration, microdialysis probes were inserted into the medial vastus muscle and into the periumbilical subcutaneous adipose layer of healthy volunteers. Following single oral dose administration of 300 mg or i.v. infusion of 240 mg theophylline, in vivo time courses of theophylline concentrations were monitored in tissues and plasma. Major pharmacokinetic parameters (c_max, t_max, AUC) were calculated for plasma and tissue time courses. The mean AUC_tissue /AUC_plasma-ratio was 0.56 (p.o.) and 0.55 (i.v.) for muscle and 0.55 (p.o.) and 0.72 (i.v.) for subcutaneous adipose tissue.We conclude that microdialysis provides important information on the distribution and the tissue pharmacokinetics of theophylline.Abbreviations FPIA Fluorescence polarisation immuno assay - AUC Area under the curve - t_max Time to peak concentration - c_max Peak concentration     

Trichinellosis in immigrants in Switzerland

We describe a case of trichinellosis diagnosed at the Division of Infectious Diseases, Hospital of Lugano, in January 2009. This case was associated with a cluster of cases and was traced to the consumption of contaminated meat after a wild boar hunt in Bosnia.     

Hyperkalaemia in patients in hospital

A survey of all laboratory blood specimens with a plasma potassium concentration greater than or equal to 5.5 mmol/L was conducted over a three month period. Of 331 specimens with hyperkalaemia, 71 were excluded because the specimens was haemolysed, old or contaminated. The laboratory served a population of 348,561 and during this time measured the plasma potassium on 25,016 occasions. Sixty-six outpatients and 20 neonates were not evaluated. The survey was undertaken on 86 of 102 inpatients (46 males), 48 of whom were over 66 years of age. Fifty-seven patients were admitted under a medical service and 29 under a surgical service. Fifty-nine had a single episode of hyperkalaemia. Thirty-two underwent a surgical procedure. The commonest contributing factor was impaired renal function which was present in 71 (83%) patients. Although a definitive causative role for drugs could be identified in only five patients, in 52 (60%) patients drugs were a contributing factor (potassium supplements 24, ACE inhibitors 16, nonsteroidal antiinflammatory drugs 12). Thirty-five of the 86 (41%) patients died during their hospital admission. Nineteen of the 35 deaths occurred within three days of the hyperkalaemia being recorded. A normal plasma potassium was eventually documented in 50 of the 86 patients. Of the remaining 36 patients, 25 (69%) subsequently died. In general the treatment of patients with hyperkalaemia focused on identifying and treating the underlying cause. Hyperkalaemia must always be considered seriously and regard given to the overall clinical status of the patient, with particular attention to drug therapy, renal and cardiac function, acid base status and the possibility of sepsis.     

Changes in angiopoietin expression in glomeruli involved in glomerulosclerosis in rats with daunorubicin-induced nephrosis

AIM: To study the potential pathological role of endogenous angiopoietins in daunorubicin-induced progressive glomerulosclerosis in rats. METHODS: Seventy male Wistar rats were allocated randomly into a daunorubicin group (DRB; n=40) or a control group (n=30). The rats in the DRB group were injected with DRB (15 mg/kg), in their tails. Subsequently, at intervals of 1, 2, 4, 6, 8, and 12 weeks, 5 male Wistar rats in each group were chosen randomly for 24 h urinary protein quantitative measurements (24 h UPQM), and determination of plasma tumor necrosis factor alpha (TNF-alpha), angiopoietin-1 (Ang1), and angiopoietin-2 (Ang2) levels. Kidney sections were examined by electron microscopy, Periodic Acid Schiff (PAS) staining, immunohistochemical staining and in situ hybridization histochemistry. RESULTS: As glomerulosclerosis progressed in the DRB group, expression of Ang1 mRNA and protein in glomeruli decreased and expression of TNF-alpha protein, Ang2 mRNA and protein in glomeruli increased. Expression of Ang1 mRNA and protein in glomeruli were negatively correlated with 24 h UPQM, Fn protein expression, and mean area of extracellular matrix (MAECM). In comparison, expression of Ang2 mRNA and protein in glomeruli were positively correlated with 24 h UPQM, Fn protein expression and MAECM; furthermore, there was a positive correlation between plasma Ang2 and 24 h UPQM. Plasma TNF-alpha and expression of TNF-alpha in glomeruli were positively correlated with expression of Ang2 mRNA and protein in glomeruli. There was a negative correlation between Ang1 protein expression and Ang2 protein expression in glomeruli. CONCLUSION: During DRB-induced glomerulosclerosis, podocyte injury led to a shift in the balance of Ang1 and Ang2 in glomeruli. Increased TNF-alpha in plasma and glomeruli may upregulate Ang2 expression in glomeruli. Elevated Ang2 in both plasma and glomeruli may mediate protein permeability through the glomerular filtration barrier. Moreover, local expression of Ang2 may facilitate the progress of glomerulosclerosis by upregulating a component expression of extracellular matrix.     

Deoxynivalenol in cereals in Russia

A survey of the occurrence of deoxynivalenol (DON) and zearalenone (ZEN) in wheat, rye, barley and maize harvested in 1989-2001 in several regions of Russia has been conducted. A total of 5652 samples of cereals were analysed for DON and ZEN by using TLC and normal-phase HPLC with UV-detector. DON was detected in 69% of 2166 samples from Krasnodar region which is considered to be the major Fusarium endemic region of Russia. The contamination levels ranged from 0.1 till 8.6 ppm, MTEL was exceeded in 37% of these samples. The positive correlation between DON concentration and a percentage of Fusaria-damaged wheat kernels has been shown. DON occurrence and contamination levels were much lower that for wheat. Based on the results of monitoring and the data of average actual consumption of wheat products in Russia, the estimated daily intake of DON per 1 kg of body weight (EDI)was calculated. EDI varied from 0.07 ug in 1990-1991 till 1.40 ug in 1992. Although average EDI were lower than adopted tolerable daily intake (TDI, 3 ug/kg body weight) EDIs for the North-Caucasian region in some cases exceeded TDI.     

Morphine and dynorphins in lipid mobilization in rats in vitro

In vitro lipid-mobilizing activities of morphine (MO) and dynorphin-(1-10) amide (DYA) were compared using adipocytes of young adult rats (body weight 170-200 g, age 50-60 days, diameter of adipocytes 54 +/- 1.12 microns) and of 20-month-old rats (body weight 500-690 g, diameter of adipocytes 99.5 +/- 3.0 microns). The adipokinetic activities of adenosine deaminase (ADA) and dynorphin-(1-13) (DY) were also tested. In the experiments 0.16 units of ADA did not influence basal or stimulated lipolysis, whereas DY exerted a slight but statistically significant adipokinetic effect. In three experimental series the EC50 of MO ranged between 0.89 and 14.60 mumol l-1, the EC50 of DYA in young rats was estimated as 0.8 mumol l-1 and in old animals, 1.3 mumol l-1. Statistically significant differences in the lipid-mobilizing potency between DYA and MO could be observed only in one experimental series in young rats. Expressed in percent of maximum lipolysis induced by isoprenaline, the maximum lipolytic response to DYA in young animals was significantly lower (Emax 26.1 +/- 1.9) when compared to the maximum effect of MO (Emax 76.3 +/- 8.5 and 68.9 +/- 3.5, respectively). Adipocytes of old rats seemed to be more sensitive not only against MO but also against DYA. When studying lipolysis no signs of competitive dualism could be observed in the interaction between MO and DYA. The possibility of two or more independent lipid-mobilizing mechanisms in the effect of the two opioids compared cannot be excluded.     

Viral diarrhoea in young children in two districts in Nigeria

OBJECTIVES: To determine the prevalence of viral agents of diarrhoea in Ilorin and Lagos, two zones in Nigeria. DESIGN: A survey of young children who had clinically confirmed diarrhoea. SETTING: University of Ilorin Teaching Hospital in Ilorin, Kware State and the Massey Street Children's Hospital in Lagos State, Nigeria. SUBJECTS: 108 children under the age of five. RESULTS: The prevalence rates observed were 33.3% for rotavirus, 6.7% for adenovirus and 1.2% for astrovirus. The rotavirus strains were characterized further. PAGE determined the presence of seven patterns of RNA electropherotypes, with one short RN patterns and six long patterns. The G and P types of selected rotavirus positive samples were characterized by RT-PCR techniques. The VP7 G typing showed that GI was the most prevalent single strain found (8.3%), while G3 and G4 accounted for 6.7% and 1.7%. The rate of mixed G serotypes was 26.7%. The P[6] genotype was the most prevalent (52%) and the P[4] had a prevalence of 8%. The mixed P genotype accounted for 28% of the rotavirus strains. The high rate of mixed infection may have an implication on vaccine development. CONCLUSION: Rotavirus was the most prevalent virus in the study with astrovirus being the second most prevalent. There was only a single incidence of astrovirus.     

Priorisation in health-care; drug-reimbursement priorities in Hungary in 2004

In our research we assessed the drug reimbursement of the National Health Insurance Fund Administration (NHIFA) in different ATC groups. We used the aggregated data of retail pharmacies in 2004, analysing separately the accentuated and elevated categories associated with medical indications. According to the 2004 data it was the drugs for cardiovascular; endocrine and metabolic disorders affecting the largest population and making the highest proportion of the total reimbursement. In addition, the turnover of some drugs for mental disorders was also significant. As for the number of patients in the cancer group it is much smaller, but as a result of the huge costs of their therapies these belong to the highest reimbursed categories as well. Without the special, separately financed category the annual drug subsidy was 257 bill. HUF, which totalled 423 bill. HUF on consumer price. The reimbursement of the NHIFA in the top 25 categories exceeded 177 bill. HUF. In the accentuated category the contribution of the NHIFA approximated 49 bill. HUF spent on the treatment of cancer, diabetic and some psychiatric disorders. In the elevated category based on health status the products of mental, digestive, bone and respiratory systems disorders were responsible for the highest turnover with more than 55 bill. HUF subsidy. Besides knowing the amount of reimbursement it is also important to be familiar with the size of affected, treated population. However in many cases we do not have any detailed, up-to-date Hungarian data, so the under-, or the possible overtreatment can hardly be analysed accurately.     

Reversible defect in cAMP metabolism in lymphocytes in malaria infection

Peripheral blood lymphocytes were observed to have a defect in adenosine 3',5'-monophosphate (cAMP) metabolism during acute malaria infection which reversed once parasites were eliminated from the host circulation. The defect was characterized by decreased intracellular cAMP levels in lymphocytes and by hyporesponsiveness to adenosine or forskolin stimulation of cAMP production. These biochemical changes appeared to correlate functionally with a reduction in the proliferative response of lymphocytes to concanavalin A. A defect in the second messenger role of cAMP in immune effector cells may underlie immunosuppression in malaria infection.     

Polymorphisms in genes involved in neurotransmission in relation to smoking

Smoking behavior is influenced by both genetic and environmental factors. The genetic contribution to smoking behavior is at least as great as its contribution to alcoholism. Much progress has been achieved in genomic research related to cigarette-smoking within recent years. Linkage studies indicate that there are several loci linked to smoking, and candidate genes that are related to neurotransmission have been examined. Possible associated genes include cytochrome P450 subfamily polypeptide 6 (CYP2A6), dopamine D₁, D₂, and D₄ receptors, dopamine transporter, and serotonin transporter genes. There are other important candidate genes but studies evaluating the link with smoking have not been reported. These include genes encoding the dopamine D₃ and D₅ receptors, serotonin receptors, tyrosine hydroxylase, trytophan 2,3-dioxygenase, opioid receptors, and cannabinoid receptors. Since smoking-related factors are extremely complex, studies of diverse populations and of many aspects of smoking behavior including initiation, maintenance, cessation, relapse, and influence of environmental factors are needed to identify smoking-associated genes. We now review genetic polymorphisms reported to be involved in neurotransmission in relation to smoking.     

Disease control in asthmatic children seen in private practice in Switzerland

BACKGROUND: Asthma is the most common chronic childhood disease in Switzerland with a prevalence of 10%. Asthma has a high economic burden accounting for high medical costs. Assessment of disease control is likely to be of help in the implementation of strategies to improve asthma. Therefore, we aimed to evaluate asthma control and therapy regimens among children in private practice. METHODS: We assessed asthma control as well as therapy regimens in 575 asthmatic children in an experience programme in Switzerland by using an abbreviated questionnaire based on the asthma control questionnaire and the child health questionnaire on Visit 1 and Visit 2. RESULTS: Good asthma control at Visit 1 was only present in 25.7% of asthmatic children. Occasional asthma symptoms, limitation of physical activity, nocturnal awakening and anxiety of the parent was present in 80.5%, 41.2%, 46.8% and 57% of the children, respectively. After adjustment of therapy regimens at Visit 1, mainly by adding a leukotriene receptor antagonist, asthma control was reported to be much better in 53.4% of the children at Visit 2. CONCLUSIONS: As asthma control is inadequately achieved within a major portion of asthmatic children, it is imperative to find measures to improve asthma control and hence, to reduce the burden of disease.     

Changes in immunoreactive somatostatin in brain following lidocaine-induced kindling in rat

The kindling phenomenon has become a useful model for studying epileptogenesis. The present authors have previously reported increased levels of immunoreactive somatostatin (IR-SRIF) in various regions of the brain of electrically-amygdaloid kindled (EAK) rats. In this study, an examination was made of immunoreactive somatostatin in pharmacologically-kindled (PK) rats. Sixteen male Sprague-Dawley rats were injected intraperitoneally (i.p.) with a subthreshold dose of lidocaine (60 mg/kg), once daily. Once the kindling phenomenon was established, kindled rats (7), non-kindled rats (9) and controls (6) were sacrificed by microwave irradiation. Another group of 5 rats was injected with a single suprathreshold dose of lidocaine (110 mg/kg) and killed 10 min after the resultant seizure. Various brain areas were removed and assayed for immunoreactive somatostatin in kindled rats. Immunoreactive somatostatin was significantly greater than in controls in the amygdala (56%; P less than 0.02), entorhinal + piriform cortex (50%; P less than 0.05) and hypothalamus (29%; P less than 0.02). In non-kindled rats, immunoreactive somatostatin increased only in the amygdala (58%; P less than 0.02). No difference was found in the immunoreactive somatostatin content of rats injected with an suprathreshold dose of lidocaine compared to controls. The alteration of immunoreactive somatostatin, in both lidocaine-kindled and electrically-amygdaloid kindled rats suggests a possible role of this neuropeptide in kindling.     

Gamma-glutamyltranspeptidase-mediated degradation of diclofenac-S-acyl-glutathione in vitro and in vivo in rat

Diclofenac, a nonsteroidal antiinflammatory drug, is known to be metabolized to chemically reactive intermediates that transacylate GSH forming diclofenac-S-acyl-glutathione (D-SG) in vivo in rat and in vitro in rat and human hepatocytes. Recently, it was reported that the treatment of rats with diclofenac led to a substantial decrease in the activity of hepatic gamma-glutamyltranspeptidase (gamma-GT), an extracellular canalicular membrane enzyme. Because studies have indicated that D-SG is a chemically reactive transacylating species that is excreted into rat bile, we propose that D-SG formed in the liver may be a substrate for, and potential inhibitor of, hepatic gamma-GT. The present experiments were performed to investigate the ability of D-SG to be a substrate for gamma-GT in vivo in rat and in vitro with commercially available gamma-GT enzyme. We also examined the ability of D-SG to inhibit gamma-GT in vitro. Thus, LC-MS/MS analysis of bile extracts from diclofenac-dosed rats (200 mg/kg, iv) showed the presence of the gamma-GT-mediated D-SG degradation product diclofenac-N-acyl-cysteinylglycine (D- N-CG), where a total of approximately 8 microg was excreted 6 h postadministration. When D-SG (100 microM) was incubated with gamma-GT (1 unit/mL), the GSH adduct was degraded in a linear time-dependent fashion where approximately 94 microM D- N-CG was formed after 20 min of incubation. Dialysis studies showed that inhibition of gamma-GT by D-SG was completely reversible. Further inhibition studies showed that D-SG is a competitive inhibitor of the gamma-GT enzyme. Results from theses studies indicate that D-SG is a substrate for gamma-GT; however, the conjugate may not contribute significantly to the decrease in gamma-GT activity reported to occur in vivo in rat.     

Calcium transport in rat small intestine in vitro and in vivo

Summary Intestinal calcium (Ca) transport was studied in the rat jejunum by the in vitro perfusion technique of Fisher and Parsons and in the tied loop in vivo. Mucosal uptake and absorption of Ca was examined under the following conditions: rising intraluminal Ca-concentrations (0.5–128 meq/l); inhibition of energy dependent metabolism (2,4-dinitrophenol, N₂, low temperature); net water flow, out of or into the intestinal lumen; addition of strontium (Sr); pretreatment with low Ca-diet and with 6-methyl-prednisolone.The concentration-dependent Ca absorption curve rose steeply at low Ca-concentrations but changed to a slowly rising straight line above 16 meq/l Ca⁺⁺. In contrast, Ca uptake into the intestinal wall was directly related to Ca concentration, was linear from the beginning and paralleled the straight part of the absorption curve.Ca absorption was decreased by inhibition of energy dependent metabolism, addition of Sr and pretreatment with prednisolone. Pretreatment with low Ca diet increased Ca absorption and direction of net water flow (solvent drag) had no effect on it.Mucosal uptake of Ca was similar to Ca absorption except that metabolic inhibition increased Ca uptake but decreased Ca absorption.These results are compatible with the concept of a passive mucosal uptake and of an active absorption of Ca at low intraluminal Ca concentrations with additional passive component at high Ca concentrations.Supported by the Deutsche Forschungsgemeinschaft.     

纳米材料在止血方面的研究进展

纳米材料因其独特的微观结构优势,已被广泛应用于材料制备、微电子与计算机技术、医学与健康、环境与能源等领域。与传统止血材料相比,纳米材料在一定程度上能提高传统止血药物的生物利用度和稳定性,增强药物的缓控与靶向释放,为现代化新型止血材料的发展奠定了良好的基础。对脂质体、纳米粒、自组装纳米肽、纳米纤维等多种纳米止血材料的前沿设计和应用进展进行了综述,最后简述纳米止血材料存在的问题和发展前景。     

我院2004年门急诊处方及抗菌药物合理应用分析

目的了解我院抗菌药物使用状况,为临床合理用药提供参考依据。方法随机抽取2004年门急诊处方样本2444份,依据统计学方法归纳制表并进行综合分析。结果2004年门急诊每张处方药品数平均为3.24种;注射给药处方数占西药总处方数的33.43%,高于北京三甲医院水平(约10%);抗菌药物使用率为43.54%,高于上海、武汉等城市水平(约35%);一线抗菌药物使用率为70.56%,二线抗菌药物使用率为29.37%,抗菌药物分级使用状况总体符合规定;抗菌药物联合用药比率为26.22%,单一用药比率达73.78%,属基本合理范围。结论我院抗菌药用药以一线抗菌药物为主,合理用药是主流,但也存在一定问题,宜制定相应措施,提高用药合理性和安全性。