Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

---

Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.     

2-(Acetoxyphenyl)-(Z)-styryl sulfides as cyclooxygenase inhibitors

2-(Acetoxyphenyl)-(Z)-styryl sulfides are described as selective cyclooxygenase-2 (COX-2) inhibitors, useful for treating inflammation and COX-2-mediated disorders including neoplasia. 2-(Acetoxyphenyl)-(Z)-styryl sulfide is claimed to be the most potent COX inhibitor in the series with a COX-2 selectivity ratio of 33. This compound is also claimed to be superior to celecoxib (Celebrex^®, Pfizer) in inhibiting cell growth of colorectal carcinoma cells. In this evaluation, the COX inhibitory activity of this compound is compared to that previously disclosed for diarylheterocycles and 2-(acetoxyphenyl)alkyl sulfides. The validity of the DLD-1 cell line in the growth inhibition studies is questioned based on recent literature reports indicating the lack of COX-2 expression in this cell line.     

Sleep-disordered breathing with chronic opioid use

Chronic opioid use for pain relief or as substitution therapy for illicit drug abuse is prevalent in our societies. In the US, retail distribution of methadone and oxycodone has increased by 824 and 660%, respectively, between 1997 and 2003. μ-Opioids depress respiration and deaths related to illicit and non illicit chronic opioid use are not uncommon. Since 2001 there has been an emerging literature that suggests that chronic opioid use is related to central sleep apnoea of both periodic and non-periodic breathing types, and occurs in ～ 30% of these subjects. The clinical significance of these sleep-related abnormalities are unknown. This review addresses the present knowledge of control of ventilation mechanisms during wakefulness and sleep, the effects of opioids on ventilatory control mechanisms, the sleep-disordered breathing found with chronic opioid use and a discussion regarding the future research directions in this area.     

Drug targets for cognitive enhancement in neuropsychiatric disorders

The investigation of novel drug targets for treating cognitive impairments associated with neurological and psychiatric disorders remains a primary focus of study in central nervous system (CNS) research. Many promising new therapies are progressing through preclinical and clinical development, and offer the potential of improved treatment options for neurodegenerative diseases such as Alzheimer's disease (AD) as well as other disorders that have not been particularly well treated to date like the cognitive impairments associated with schizophrenia (CIAS). Among targets under investigation, cholinergic receptors have received much attention with several nicotinic agonists (α7 and α4β2) actively in clinical trials for the treatment of AD, CIAS and attention deficit hyperactivity disorder (ADHD). Both glutamatergic and serotonergic (5-HT) agonists and antagonists have profound effects on neurotransmission and improve cognitive function in preclinical experiments with animals; some of these compounds are now in proof-of-concept studies in humans. Several histamine H3 receptor antagonists are in clinical development not only for cognitive enhancement, but also for the treatment of narcolepsy and cognitive deficits due to sleep deprivation because of their expression in brain sleep centers. Compounds that dampen inhibitory tone (e.g., GABA_A α5 inverse agonists) or elevate excitatory tone (e.g., glycine transporter inhibitors) offer novel approaches for treating diseases such as schizophrenia, AD and Down syndrome. In addition to cell surface receptors, intracellular drug targets such as the phosphodiesterases (PDEs) are known to impact signaling pathways that affect long-term memory formation and working memory. Overall, there is a genuine need to treat cognitive deficits associated with many neuropsychiatric conditions as well as an increasingly aging population.     

RP-HPLC同时测定暗紫贝母中10个核苷及碱基类成分的含量

目的:建立RP-HPLC-DAD同时测定暗紫贝母药材中5个核苷类活性成分(尿苷、鸟苷、胸苷、腺苷、肌苷)及5个游离的碱基(腺嘌呤、胸腺嘧啶、鸟嘌呤、尿嘧啶、胞嘧啶)含量的方法。方法:采用Agilent Zorbax Bonus-RP C18色谱柱(4.6 mm×250 mm,5μm);流动相为甲醇和水,梯度洗脱,流速1 mL·min-1;检测波长260 nm;柱温30℃。结果:胞嘧啶、尿苷、鸟苷、胸苷、腺苷、腺嘌呤、肌苷、胸腺嘧啶、鸟嘌呤、尿嘧啶的质量浓度分别在1.78～56.80 mg·L-1、1.84～59.00 mg·L-1、1.58～50.60 mg·L-1、1.73～55.30 mg·L-1、1.78～57.10 mg·L-1、1.63～52.10 mg·L-1、1.79～57.20 mg·L-1、1.80～57.70 mg·L-1、1.63～52.30 mg·L-1、1.63～52.30 mg·L-1范围内与峰面积呈良好线性关系,平均回收率为97.7%～103.2%,RSD≤2.2%。结论:建立了RP-HPLC-DAD同时测定暗紫贝母药材中10个核苷及碱基类成分含量的方法,该方法简单,重复性好,准确可靠;暗紫贝母药材中鸟苷、尿苷、胸苷、腺苷含量较高;青海久治、大通产暗紫贝母药材中核苷含量均高于四川松潘;青海2个产地比较,大通产暗紫贝母药材中核苷含量又明显高于久治。     

Similarities and differences between the subchronic and withdrawal effects of clozapine and olanzapine on forelimb force steadiness

 The purpose of this study was to compare the subchronic, low-dose effects of clozapine with those of olanzapine in a learned behavioral task previously shown to distinguish between clozapine and haloperidol with acute and subchronic treatment regimes. Rats were trained to use a single forelimb to press a force-recording operandum and simultaneously to lick water from a dipper that remained available while forelimb force exceeded a modest lower limit. Analysis of the resulting force-time recordings provided measures of task engagement (time on task – analogous to response rate), lick rhythm, tremor, ballistic (maximum force) and tonic (hold force) forelimb force measures, as well as the durations of the individual responses. In a between-groups dosing design, five separate groups of rats received vehicle, clozapine 1.0 or 5.0 mg/kg, olanzapine 0.5 or 1.0 mg/kg daily for 27 days. A 7-day withdrawal period followed. On days 22 and 26 of antipsychotic drug treatment, all rats additionally received 0.3 mg/kg trihexyphenidyl or 1.0 mg/kg quipazine, respectively. The effects of olanzapine and clozapine were similar in that both drugs reduced time on task, increased response duration, and slowed lick rhythm. The two drugs differed in that clozapine reduced the force and tremor measures but olanzapine did not. Both tolerance and withdrawal effects, as reflected by the tremor measure, were observed for clozapine but not for olanzapine. Trihexyphenidyl further increased the duration of responses already lengthened by clozapine; in contrast, trihexyphenidyl decreased the duration lengthening effect of olanzapine. Taken together, the results indicated that olanzapine did not have the antitremor and hypotonic effects displayed by clozapine, and olanzapine did not induce tolerance and withdrawal phenomena as clozapine did. Received: 28 January 1997 / Final version: 14 March 1997     

Withdrawal from a self-administered or non-contingent cocaine binge: differences in ultrasonic distress vocalizations in rats

After termination of a self-administered cocaine “binge,” rats emit ultrasonic vocalizations (USVs) and these calls may represent affective distress. The present study investigated whether the rates of USVs as indices of withdrawal from a period of continuous access, depends on cocaine being self-administered versus given non-contingently. Five days after implantation of a jugular catheter, triads of rats that were matched for housing, food-training and surgery were placed into experimental chambers. The active rats were allowed to acquire self-administration of cocaine (0.5 mg) while the two yoked animals passively received either cocaine (0.5 mg) or saline according to the active animal’s pattern of administration. Once the active animal responded at a stable rate over 3 days, with every third lever press being reinforced by cocaine (FR3), it was allowed free access to cocaine (0.5 mg) for 16 h. Subsequently, all animals were exposed to 18 air puffs (10 psi) at 0, or 1, 3, 5, 7 and 14 days after the “binge”. Immediately following the binge, there was no significant difference in the rate of startle-induced USVs between the active cocaine group and the yoked saline group. However, the yoked or non-contigent cocaine rats emitted significantly higher rates of USVs immediately after the last cocaine infusion. At the time of the peak increase in USVs, the active and yoked cocaine groups were significantly different. For up to 5 days after unlimited cocaine access, the active and passive-cocaine groups showed an increase in USVs response when compared to the yoked saline group. The emerging increase in USVs and their gradual decline observed after termination of a cocaine “binge” can be interpreted as an abstinence phenomenon. The non-contingent cocaine appears to be highly aversive, as indicated by the immediate significant increase in the rate of USVs after termination of a cocaine “binge”. Received: 29 August 1997/Final version: 17 October 1997     

Progress in drug delivery system for fibrosis therapy

Fibrosis is a necessary process in the progression of chronic disease to cirrhosis or even cancer,which is a serious disease threatening human health.Recent stu...     

肝炎后肝硬化时肝脏体积变化的临床研究

利用数字图像处理系统和“三维信息提取与三维图像重建”的方法,通过肝脏 CT 断层影像,成功地重建了活体肝脏三维图像,并测出活体肝脏体积。为排除体格差异,再根据体表面积,求出每单位体表面积的肝脏体积。临床应用42例,其中非肝硬化组8例,均值为773.88±69.17cm~3/m~2;肝炎后肝硬化组34例,均值为493.72±102.50cm~3/m~2。两组均值的差异显著(P<0.001)。肝炎后肝硬化组中,各级肝功能的肝体积无统计学差异(P>0.05)。肝体积大于400cm~3/m~2者与小于400cm~3/m~2者的术后顺利康复率差异显著(P<0.01)。