Mechanistic Investigation of Liver Injury Induced by BMS-932481, an Experimental ɣ-Secretase Modulator

BMS-932481 was designed to modulate ɣ-secretase activity to produce shorter and less amyloidogenic peptides, potentially averting liabilities associated with complete enzymatic inhibition. Although it demonstrated the intended pharmacology in the clinic, BMS-932481 unexpectedly caused drug-induced liver injury (DILI) in a multiple ascending dose study characterized by dose- and exposure-dependence, delayed onset manifestation, and a high incidence of hepatocellular damage. Retrospective studies investigating the disposition and probable mechanisms of toxicity of BMS-932481 are presented here. These included a mass balance study in bile-duct-cannulated rats and a metabolite profiling study in human hepatocytes, which together demonstrated oxidative metabolism followed by biliary elimination as the primary means of disposition. Additionally, minimal protein covalent binding in hepatocytes and lack of bioactivation products excluded reactive metabolite formation as a probable toxicological mechanism. However, BMS-932481 and three major oxidative metabolites were found to inhibit the bile salt export pump (BSEP) and multidrug resistance protein 4 (MRP4) in vitro. Considering human plasma concentrations, the IC50 values against these efflux transporters were clinically meaningful, particularly in the high dose cohort. Active uptake into human hepatocytes in vitro suggested the potential for hepatic levels of BMS-932481 to be elevated further above plasma concentrations, enhancing DILI risk. Conversely, measures of mitochondrial functional decline in hepatocytes treated with BMS-932481 were minimal or modest, suggesting limited contributions to DILI. Collectively, these findings suggested that repeat administration of BMS-932481 likely resulted in high hepatic concentrations of BMS-932481 and its metabolites, which disrupted bile acid transport via BSEP and MRP4, elevating serum biomarkers of liver injury.

Discovery of BMS-986339, a Pharmacologically Differentiated Farnesoid X Receptor Agonist for the Treatment of Nonalcoholic Steatohepatitis

While several farnesoid X receptor (FXR) agonists under clinical investigation for the treatment of nonalcoholic steatohepatitis (NASH) have shown beneficial effects, adverse effects such as pruritus and elevation of plasma lipids have limited their clinical efficacy and approvability. Herein, we report the discovery and preclinical evaluation of compound 32 (BMS-986339), a nonbile acid FXR agonist with a pharmacologically distinct profile relative to our previously reported agonist BMS-986318. Compound 32 exhibited potent in vitro and in vivo activation of FXR, albeit with a context-dependent profile that resulted in tissue-selective effects in vivo. To our knowledge, this is the first report that demonstrates differential induction of Fgf15 in the liver and ileum by FXR agonists in vivo. Compound 32 demonstrated robust antifibrotic efficacy despite reduced activation of certain genes in the liver, suggesting that the additional pharmacology of BMS-986318 does not further benefit efficacy, possibly presenting an opportunity for reduced adverse effects. Further evaluation in humans is warranted to validate this hypothesis.

Discovery of BMS-986318, a Potent Nonbile Acid FXR Agonist for the Treatment of Nonalcoholic Steatohepatitis

Herein we report the discovery and preclinical biological evaluation of 6-(2-(5-cyclopropyl-3-(3,5-dichloropyridin-4-yl)isoxazol-4-yl)-7-azaspiro[3.5]non-1-en-7-yl)-4-(trifluoromethyl)quinoline-2-carboxylic acid, compound 1 (BMS-986318), a nonbile acid farnesoid X receptor (FXR) agonist. Compound 1 exhibits potent in vitro and in vivo activation of FXR, has a suitable ADME profile, and demonstrates efficacy in the mouse bile duct ligation model of liver cholestasis and fibrosis. The overall profile of compound 1 supports its continued evaluation.

Metabolic and Pharmaceutical Aspects of Fluorinated Compounds

The applications of fluorine in drug design continue to expand, facilitated by an improved understanding of its effects on physicochemical properties and the development of synthetic methodologies that are providing access to new fluorinated motifs. In turn, studies of fluorinated molecules are providing deeper insights into the effects of fluorine on metabolic pathways, distribution, and disposition. Despite the high strength of the C-F bond, the departure of fluoride from metabolic intermediates can be facile. This reactivity has been leveraged in the design of mechanism-based enzyme inhibitors and has influenced the metabolic fate of fluorinated compounds. In this Perspective, we summarize the literature associated with the metabolism of fluorinated molecules, focusing on examples where the presence of fluorine influences the metabolic profile. These studies have revealed potentially problematic outcomes with some fluorinated motifs and are enhancing our understanding of how fluorine should be deployed.

Therapeutic effect of pregabalin on radiotherapy-induced trismus in nasopharyngeal carcinoma patients

AIMS

To evaluate the effect of pregabalin on radiotherapy-induced trismus in patients with nasopharyngeal carcinoma, a hospital-based, clinical retrospective cohort study was conducted.

MATERIALS AND METHODS

Data were collected on patients diagnosed with radiotherapy-induced trismus from March 2014 and March 2016 in the department of neurology in our hospital. Patients in the treatment group were administrated pregabalin for 8 weeks combined with rehabilitation, while the control group only received rehabilitation. The clinical therapeutic effects were observed and evaluated by mandibular motion, severity of trismus measured by late effects of normal tissues/subjective and objective medical analysis (LENT/SOMA) scales, and quality of life (QOL) assessed using the World Health Organization QOL instrument (WHOQOL-BREF) at baseline, week 4 and week 8 during treatment in these two groups, respectively.

RESULTS

In the treatment group, the number of patients with improvement on maximal vertical dimension (MVD) was significantly more than controls at week 4 and week 8 (P=0.013, P=0.004, respectively). Moreover, at week 4 and week 8, the severity of trismus was both significantly improved on LENT/SOMA grade in treatment group (P=0.047, P=0.032, respectively). And at week 8, the physical health and the whole life domain of the WHOQOL-BREF score were significantly increased (P=0.037, P=0.034, respectively). In the treatment group, 11 patients (36.7%) presented dizziness, and 7 patients (23.3%) presented somnolence.

CONCLUSIONS

Administration of pregabalin, in adjunct to rehabilitation, might provide a better outcome in patients with radiotherapy-induced trismus.

Identification and Preclinical Evaluation of the Bicyclic Pyrimidine γ-Secretase Modulator BMS-932481

A triazine hit identified from a screen of the BMS compound collection was optimized for potency, in vivo activity, and off-target profile to produce the bicyclic pyrimidine γ-secretase modulator BMS-932481. The compound showed robust reductions of Aβ_1-42 and Aβ_1-40 in the plasma, brain, and cerebrospinal fluid of mice and rats. Consistent with the γ-secretase modulator mechanism, increases in Aβ_1-37 and Aβ_1-38 were observed, with no change in the total amount of Aβ_1-x produced. No Notch-based toxicity was observed, and the overall preclinical profile of BMS-932481 supported its further evaluation in human clinical trials.

BMS-986163, a Negative Allosteric Modulator of GluN2B with Potential Utility in Major Depressive Disorder

There is a significant unmet medical need for more efficacious and rapidly acting antidepressants. Toward this end, negative allosteric modulators of the N-methyl-d-aspartate receptor subtype GluN2B have demonstrated encouraging therapeutic potential. We report herein the discovery and preclinical profile of a water-soluble intravenous prodrug BMS-986163 (6) and its active parent molecule BMS-986169 (5), which demonstrated high binding affinity for the GluN2B allosteric site (K_i = 4.0 nM) and selective inhibition of GluN2B receptor function (IC₅₀ = 24 nM) in cells. The conversion of prodrug 6 to parent 5 was rapid in vitro and in vivo across preclinical species. After intravenous administration, compounds 5 and 6 have exhibited robust levels of ex vivo GluN2B target engagement in rodents and antidepressant-like activity in mice. No significant off-target activity was observed for 5, 6, or the major circulating metabolites met-1 and met-2. The prodrug BMS-986163 (6) has demonstrated an acceptable safety and toxicology profile and was selected as a preclinical candidate for further evaluation in major depressive disorder.

Bioactivation of cyclopropyl rings by P450: an observation encountered during the optimisation of a series of hepatitis C virus NS5B inhibitors

1. Due to its unique C-C and C-H bonding properties, conformational preferences and relative hydrophilicity, the cyclopropyl ring has been used as a synthetic building block in drug discovery to modulate potency and drug-like properties. During an effort to discover inhibitors of the hepatitis C virus non-structural protein 5B with improved potency and genotype-coverage profiles, the use of a pyrimidinylcyclopropylbenzamide moiety linked to a C6-substituted benzofuran or azabenzofuran core scaffold was explored in an effort to balance antiviral potency and metabolic stability. 2. In vitro metabolism studies of two compounds from this C6-substituted series revealed an NADPH-dependent bioactivation pathway leading to the formation of multiple glutathione (GSH) conjugates. Analysis of these conjugates by LC-MS and NMR demonstrated that the cyclopropyl group was the site of bioactivation. Based on the putative structures and molecular weights of the cyclopropyl-GSH conjugates, a multi-step mechanism was proposed to explain the formation of these metabolites by P450. This mechanism involves hydrogen atom abstraction to form a cyclopropyl radical, followed by a ring opening rearrangement and reaction with GSH. 3. These findings provided important information to the medicinal chemistry team which responded by replacing the cyclopropyl ring with a gem-dimethyl group. Subsequent compounds bearing this feature were shown to avert the bioactivation pathways in question.

Improving Metabolic Stability with Deuterium: The Discovery of BMT-052, a Pan-genotypic HCV NS5B Polymerase Inhibitor

Iterative structure-activity analyses in a class of highly functionalized furo[2,3-b]pyridines led to the identification of the second generation pan-genotypic hepatitis C virus NS5B polymerase primer grip inhibitor BMT-052 (14), a potential clinical candidate. The key challenge of poor metabolic stability was overcome by strategic incorporation of deuterium at potential metabolic soft spots. The preclinical profile and status of BMT-052 (14) is described.

Discovery of a Hepatitis C Virus NS5B Replicase Palm Site Allosteric Inhibitor (BMS-929075) Advanced to Phase 1 Clinical Studies

The hepatitis C virus (HCV) NS5B replicase is a prime target for the development of direct-acting antiviral drugs for the treatment of chronic HCV infection. Inspired by the overlay of bound structures of three structurally distinct NS5B palm site allosteric inhibitors, the high-throughput screening hit anthranilic acid 4, the known benzofuran analogue 5, and the benzothiadiazine derivative 6, an optimization process utilizing the simple benzofuran template 7 as a starting point for a fragment growing approach was pursued. A delicate balance of molecular properties achieved via disciplined lipophilicity changes was essential to achieve both high affinity binding and a stringent targeted absorption, distribution, metabolism, and excretion profile. These efforts led to the discovery of BMS-929075 (37), which maintained ligand efficiency relative to early leads, demonstrated efficacy in a triple combination regimen in HCV replicon cells, and exhibited consistently high oral bioavailability and pharmacokinetic parameters across preclinical animal species. The human PK properties from the Phase I clinical studies of 37 were better than anticipated and suggest promising potential for QD administration.

The discovery of a pan-genotypic, primer grip inhibitor of HCV NS5B polymerase

The development of a series of novel 7-azabenzofurans exhibiting pan-genotype inhibition of HCV NS5B polymerase via binding to the primer grip site is presented. Many challenges, including poor oral bioavailability, high clearance, bioactivation, high human serum shift, and metabolic stability were encountered and overcome through SAR studies. This work culminated in the selection of BMS-986139 (43) as a preclinical candidate.

Development of 1H-Pyrazolo[3,4-b]pyridines as Metabotropic Glutamate Receptor 5 Positive Allosteric Modulators

The metabotropic glutamate receptor 5 (mGluR5) is an attractive target for the treatment of schizophrenia due to its role in regulating glutamatergic signaling in association with the N-methyl-d-aspartate receptor (NMDAR). We describe the synthesis of 1H-pyrazolo[3,4-b]pyridines and their utility as mGluR5 positive allosteric modulators (PAMs) without inherent agonist activity. A facile and convergent synthetic route provided access to a structurally diverse set of analogues that contain neither the aryl-acetylene-aryl nor aryl-methyleneoxy-aryl elements, the predominant structural motifs described in the literature. Binding studies suggest that members of our new chemotype do not engage the receptor at the MPEP and CPPHA mGluR5 allosteric sites. SAR studies culminated in the first non-MPEP site PAM, 1H-pyrazolo[3,4-b]pyridine 31 (BMT-145027), to improve cognition in a preclinical rodent model of learning and memory.

Discovery, Synthesis, and Preclinical Characterization of N-(3-Chloro-4-fluorophenyl)-1H-pyrazolo[4,3-b]pyridin-3-amine (VU0418506), a Novel Positive Allosteric Modulator of the Metabotropic Glutamate Receptor 4 (mGlu4)

The efficacy of positive allosteric modulators (PAMs) of the metabotropic glutamate receptor 4 (mGlu4) in preclinical rodent models of Parkinson's disease has been established by a number of groups. Here, we report an advanced preclinically characterized mGlu4 PAM, N-(3-chloro-4-fluorophenyl)-1H-pyrazolo[4,3-b]pyridin-3-amine (VU0418506). We detail the discovery of VU0418506 starting from a common picolinamide core scaffold and evaluation of a number of amide bioisosteres leading to the novel pyrazolo[4,3-b]pyridine head group. VU0418506 has been characterized as a potent and selective mGlu4 PAM with suitable in vivo pharmacokinetic properties in three preclinical safety species.

Robust Translation of γ-Secretase Modulator Pharmacology across Preclinical Species and Human Subjects

The amyloid-β peptide (Aβ)—in particular, the 42–amino acid form, Aβ1-42—is thought to play a key role in the pathogenesis of Alzheimer’s disease (AD). Thus, several therapeutic modalities aiming to inhibit Aβ synthesis or increase the clearance of Aβ have entered clinical trials, including γ-secretase inhibitors, anti-Aβ antibodies, and amyloid-β precursor protein cleaving enzyme inhibitors. A unique class of small molecules, γ-secretase modulators (GSMs), selectively reduce Aβ1-42 production, and may also decrease Aβ1-40 while simultaneously increasing one or more shorter Aβ peptides, such as Aβ1-38 and Aβ1-37. GSMs are particularly attractive because they do not alter the total amount of Aβ peptides produced by γ-secretase activity; they spare the processing of other γ-secretase substrates, such as Notch; and they do not cause accumulation of the potentially toxic processing intermediate, β-C-terminal fragment. This report describes the translation of pharmacological activity across species for two novel GSMs, (S)-7-(4-fluorophenyl)-N2-(3-methoxy-4-(3-methyl-1H-1,2,4-triazol-1-yl)phenyl)-N4-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidine-2,4-diamine (BMS-932481) and (S,Z)-17-(4-chloro-2-fluorophenyl)-34-(3-methyl-1H-1,2,4-triazol-1-yl)-16,17-dihydro-15H-4-oxa-2,9-diaza-1(2,4)-cyclopenta[d]pyrimidina-3(1,3)-benzenacyclononaphan-6-ene (BMS-986133). These GSMs are highly potent in vitro, exhibit dose- and time-dependent activity in vivo, and have consistent levels of pharmacological effect across rats, dogs, monkeys, and human subjects. In rats, the two GSMs exhibit similar pharmacokinetics/pharmacodynamics between the brain and cerebrospinal fluid. In all species, GSM treatment decreased Aβ1-42 and Aβ1-40 levels while increasing Aβ1-38 and Aβ1-37 by a corresponding amount. Thus, the GSM mechanism and central activity translate across preclinical species and humans, thereby validating this therapeutic modality for potential utility in AD.

Cost to government and society of chronic kidney disease stage 1-5: a national cohort study

BACKGROUND

Costs associated with chronic kidney disease (CKD) are not well documented. Understanding such costs is important to inform economic evaluations of prevention strategies and treatment options.

AIM

To estimate the costs associated with CKD in Australia.

METHODS

We used data from the 2004/2005 AusDiab study, a national longitudinal population-based study of non-institutionalised Australian adults aged ≥25 years. We included 6138 participants with CKD, diabetes and healthcare cost data. The annual age and sex-adjusted costs per person were estimated using a generalised linear model. Costs were inflated from 2005 to 2012 Australian dollars using best practice methods.

RESULTS

Among 6138 study participants, there was a significant difference in the per-person annual direct healthcare costs by CKD status, increasing from $1829 (95% confidence interval (CI): $1740-1943) for those without CKD to $14 545 (95% CI: $5680-44 842) for those with stage 4 or 5 CKD (P < 0.01). Similarly, there was a significant difference in the per-person annual direct non-healthcare costs by CKD status from $524 (95% CI: $413-641) for those without CKD to $2349 (95% CI: $386-5156) for those with stage 4 or 5 CKD (P < 0.01). Diabetes is a common cause of CKD and is associated with increased health costs. Costs per person were higher for those with diabetes than those without diabetes in all CKD groups; however, this was significant only for those without CKD and those with early stage (stage 1 or 2) CKD.

CONCLUSION

Individuals with CKD incur 85% higher healthcare costs and 50% higher government subsidies than individuals without CKD, and costs increase by CKD stage. Primary and secondary prevention strategies may reduce costs and warrant further consideration.

Fragmentation and high entropy of neonatal experience predict adolescent emotional outcome

Vulnerability to emotional disorders including depression derives from interactions between genes and environment, especially during sensitive developmental periods. Across evolution, maternal care is a key source of environmental sensory signals to the developing brain, and a vast body of work has linked quantitative and qualitative aspects of maternal care to emotional outcome in children and animals. However, the fundamental properties of maternal signals, that promote advantageous vs pathological outcomes in the offspring, are unknown and have been a topic of intense study. We studied emotional outcomes of adolescent rats reared under routine or impoverished environments, and used mathematical approaches to analyze the nurturing behaviors of the dams. Unexpectedly, whereas the quantity and typical qualities of maternal care behaviors were indistinguishable in the two environments, their patterns and rhythms differed drastically and influenced emotional outcomes. Specifically, unpredictable, fragmented maternal care patterns translated into high-entropy rates of sensory signals to the offspring in the impoverished cages. During adolescence, these offspring had significant reductions in sucrose preference and in peer-play, two independent measures of the ability to experience pleasure. This adolescent anhedonia, often a harbinger of later depression, was not accompanied by measures of anxiety or helplessness. Dopaminergic pleasure circuits underlying anhedonia are engaged by predictable sequences of events, and predictable sensory signals during neonatal periods may be critical for their maturation. Conversely, unpredictability maternal-derived signals may disrupt these developmental processes, provoking anhedonia. In sum, high-entropy and fragmented patterns of maternal-derived sensory input to the developing brain predicts, and might promote, the development of anhedonia in rodents, with potential clinical implications.

The effect of lifestyle intervention and metformin on preventing or delaying diabetes among women with and without gestational diabetes: the Diabetes Prevention Program outcomes study 10-year follow-up

CONTEXT

Gestational diabetes (GDM) confers a high risk of type 2 diabetes. In the Diabetes Prevention Program (DPP), intensive lifestyle (ILS) and metformin prevented or delayed diabetes in women with a history of GDM.

OBJECTIVE

The objective of the study was to evaluate the impact of ILS and metformin intervention over 10 years in women with and without a history of GDM in the DPP/Diabetes Prevention Program Outcomes Study.

DESIGN

This was a randomized controlled clinical trial with an observational follow-up.

SETTING

The study was conducted at 27 clinical centers.

PARTICIPANTS

Three hundred fifty women with a history of GDM and 1416 women with previous live births but no history of GDM participated in the study. The participants had an elevated body mass index and fasting glucose and impaired glucose tolerance at study entry.

INTERVENTIONS

Interventions included placebo, ILS, or metformin.

OUTCOMES MEASURE

Outcomes measure was diabetes mellitus.

RESULTS

Over 10 years, women with a history of GDM assigned to placebo had a 48% higher risk of developing diabetes compared with women without a history of GDM. In women with a history of GDM, ILS and metformin reduced progression to diabetes compared with placebo by 35% and 40%, respectively. Among women without a history of GDM, ILS reduced the progression to diabetes by 30%, and metformin did not reduce the progression to diabetes.

CONCLUSIONS

Women with a history of GDM are at an increased risk of developing diabetes. In women with a history of GDM in the DPP/Diabetes Prevention Program Outcomes Study, both lifestyle and metformin were highly effective in reducing progression to diabetes during a 10-year follow-up period. Among women without a history of GDM, lifestyle but not metformin reduced progression to diabetes.

Identification of glutathione conjugates of acetylene-containing positive allosteric modulators of metabotropic glutamate receptor subtype 5

A recent medicinal chemistry campaign to identify positive allosteric modulators (PAMs) of metabotropic glutamate receptor subtype 5 (mGluR5) led to the discovery of potent compounds featuring an oxazolidinone structural core flanked by biaryl acetylene and haloaryl moieties. However, biotransformation studies of some of these mGluR5 PAMs demonstrated the formation of glutathione (GSH) conjugates. The conjugates in question were formed independently of NADPH as the main products in liver microsomes and liver cytosol (rat and human) and exhibited masses that were 307 u greater than their respective substrates, indicating the involvement of a reductive step in the formation of these metabolites. To further characterize the relevant metabolic sequences, GSH conjugates of (4R,5R)-5-(3-fluorophenyl)-4-(5-(pyrazin-2-ylethynyl)pyridin-3-yl)oxazolidin-2-one and (4R,5R)-5-(4-fluorophenyl)-4-(6-((3-fluoropyridin-2-yl)ethynyl)pyridin-2-yl)oxazolidin-2-one were biosynthesized and isolated. Subsequent analysis by NMR showed that GSH had reacted with the acetylene carbon atoms of these mGluR5 PAMs, suggesting a conjugate addition mechanism and implicating cytosolic and microsomal GSH S-transferases (GSTs) in catalysis. Interestingly, five closely related mGluR5 PAMs were not similarly prone to the formation of GSH conjugates in vitro. These compounds also featured acetylenes, but were flanked by either phenyl or cyclohexyl rings, which indicated that the formation of GSH conjugates was influenced by proximal functional groups that modulated the electron density of the triple bond and/or differences in enzyme-substrate specificity. These results informed an ongoing drug-discovery effort to identify mGluR5 PAMs with drug-like properties and a low risk of reactivity with endogenous thiols.

Identification and Preclinical Pharmacology of the γ-Secretase Modulator BMS-869780

Alzheimer's disease is the most prevalent cause of dementia and is associated with accumulation of amyloid-β peptide (Aβ), particularly the 42-amino acid Aβ1-42, in the brain. Aβ1-42 levels can be decreased by γ-secretase modulators (GSM), which are small molecules that modulate γ-secretase, an enzyme essential for Aβ production. BMS-869780 is a potent GSM that decreased Aβ1-42 and Aβ1-40 and increased Aβ1-37 and Aβ1-38, without inhibiting overall levels of Aβ peptides or other APP processing intermediates. BMS-869780 also did not inhibit Notch processing by γ-secretase and lowered brain Aβ1-42 without evidence of Notch-related side effects in rats. Human pharmacokinetic (PK) parameters were predicted through allometric scaling of PK in rat, dog, and monkey and were combined with the rat pharmacodynamic (PD) parameters to predict the relationship between BMS-869780 dose, exposure and Aβ1-42 levels in human. Off-target and safety margins were then based on comparisons to the predicted exposure required for robust Aβ1-42 lowering. Because of insufficient safety predictions and the relatively high predicted human daily dose of 700 mg, further evaluation of BMS-869780 as a potential clinical candidate was discontinued. Nevertheless, BMS-869780 demonstrates the potential of the GSM approach for robust lowering of brain Aβ1-42 without Notch-related side effects.

Discovery and preclinical characterization of the cyclopropylindolobenzazepine BMS-791325, a potent allosteric inhibitor of the hepatitis C virus NS5B polymerase

Described herein are structure-activity relationship studies that resulted in the optimization of the activity of members of a class of cyclopropyl-fused indolobenzazepine HCV NS5B polymerase inhibitors. Subsequent iterations of analogue design and syntheses successfully addressed off-target activities, most notably human pregnane X receptor (hPXR) transactivation, and led to significant improvements in the physicochemical properties of lead compounds. Those analogues exhibiting improved solubility and membrane permeability were shown to have notably enhanced pharmacokinetic profiles. Additionally, a series of alkyl bridged piperazine carboxamides was identified as being of particular interest, and from which the compound BMS-791325 (2) was found to have distinguishing antiviral, safety, and pharmacokinetic properties that resulted in its selection for clinical evaluation.

Cost-effectiveness of nutrition interventions in nursing home residents: a pilot intervention

OBJECTIVES

Unintentional weight loss is a prevalent and costly clinical problem among nursing home (NH) residents. One of the most common nutrition interventions for residents at risk for weight loss is oral liquid nutrition supplementation. The purpose of this study was to determine the cost effectiveness of supplements relative to offering residents' snack foods and fluids between meals to increase caloric intake.

DESIGN

Randomized, controlled trial.

SETTING

Three long-term care facilities.

PARTICIPANTS

Sixty-three long-stay residents who had an order for nutrition supplementation.

INTERVENTION

Participants were randomized into one of three groups: (1) usual NH care control; (2) supplement, or (3) between-meal snacks. For groups two and three, trained research staff provided supplements or snacks twice daily between meals, five days per week, for six weeks with assistance and encouragement to promote consumption.

MEASUREMENTS

Research staff observed residents during and between meals for two days at baseline, weekly, and post six weeks to estimate total daily caloric intake. For both intervention groups, research staff documented residents' caloric intake between meals from supplements or snack items, refusal rates and the amount of staff time required to provide each intervention.

RESULTS

Both interventions increased between meal caloric intake significantly relative to the control group and required more staff time than usual NH care. The snack intervention was slightly less expensive and more effective than the supplement intervention.

CONCLUSIONS

Offering residents a choice among a variety of foods and fluids twice per day may be a more effective nutrition intervention than oral liquid nutrition supplementation.

Comparative biotransformation of pyrazinone-containing corticotropin-releasing factor receptor-1 antagonists: minimizing the reactive metabolite formation

(S)-5-Chloro-1-(1-cyclopropylethyl)-3-(2,6-dichloro-4-(trifluoromethyl)phenylamino)pyrazin-2(1H)-one (BMS-665053), a pyrazinone-containing compound, is a potent and selective antagonist of corticotropin-releasing factor receptor-1 (CRF-R1) that showed efficacy in the defensive withdrawal model for anxiety in rats, suggesting its use as a potential treatment for anxiety and depression. In vitro metabolism studies of BMS-665053 in rat and human liver microsomes revealed cytochrome P450-mediated oxidation of the pyrazinone moiety, followed by ring opening, as the primary metabolic pathway. Detection of a series of GSH adducts in trapping experiments suggested the formation of a reactive intermediate, probably as a result of epoxidation of the pyrazinone moiety. In addition, BMS-665053 (20 mg/kg i.v.) underwent extensive metabolism in bile duct-cannulated (BDC) rats. The major drug-related materials in rat plasma were the pyrazinone oxidation products. In rat bile and urine (0-7 h), only a trace amount of the parent drug was recovered, whereas significant levels of the pyrazinone epoxide-derived metabolites and GSH-related conjugates were detected. Further evidence suggested that GSH-related conjugates also formed at the dichloroarylamine moiety possibly via an epoxide or a quinone imine intermediate. Other major metabolites in BDC rat bile and urine included glucuronide conjugates. To reduce potential liability due to metabolic activation of BMS-665053, a number of pyrazinone analogs with different substituents were synthesized and investigated for reactive metabolite formation, leading to the discovery of a CRF-R1 antagonist with diminished in vitro metabolic activation.

Role of CYP2A5 in the clearance of nicotine and cotinine: insights from studies on a Cyp2a5-null mouse model

CYP2A5, a mouse cytochrome P450 monooxygenase that shows high similarities to human CYP2A6 and CYP2A13 in protein sequence and substrate specificity, is expressed in multiple tissues, including the liver, kidney, lung, and nasal mucosa. Heterologously expressed CYP2A5 is active in the metabolism of both endogenous substrates, such as testosterone, and xenobiotic compounds, such as nicotine and cotinine. To determine the biological and pharmacological functions of CYP2A5 in vivo, we have generated a Cyp2a5-null mouse. Homozygous Cyp2a5-null mice are viable and fertile; they show no evidence of embryonic lethality or developmental deficits; and they have normal circulating levels of testosterone and progesterone. The Cyp2a5-null mouse and wild-type mouse were then used for determination of the roles of CYP2A5 in the metabolism of nicotine and its major circulating metabolite, cotinine. The results indicated that the Cyp2a5-null mouse has lower hepatic nicotine 5'-hydroxylation activity in vitro, and slower systemic clearance of both nicotine and cotinine in vivo. For both compounds, a substantially longer plasma half-life and a greater area under the concentration-time curve were observed for the Cyp2a5-null mice, compared with wild-type mice. Further pharmacokinetics analysis confirmed that the brain levels of nicotine and cotinine are also influenced by the Cyp2a5 deletion. These findings provide direct evidence that CYP2A5 is the major nicotine and cotinine oxidase in mouse liver. The Cyp2a5-null mouse will be valuable for in vivo studies on the role of CYP2A5 in drug metabolism and chemical toxicity, and for future production of CYP2A6- and CYP2A13-humanized mouse models.

Synthesis, structure-activity relationships, and in vivo evaluation of N3-phenylpyrazinones as novel corticotropin-releasing factor-1 (CRF1) receptor antagonists

Evidence suggests that corticotropin-releasing factor-1 (CRF(1)) receptor antagonists may offer therapeutic potential for the treatment of diseases associated with elevated levels of CRF such as anxiety and depression. A pyrazinone-based chemotype of CRF(1) receptor antagonists was discovered. Structure-activity relationship studies led to the identification of numerous potent analogues including 12p, a highly potent and selective CRF(1) receptor antagonist with an IC(50) value of 0.26 nM. The pharmacokinetic properties of 12p were assessed in rats and Cynomolgus monkeys. Compound 12p was efficacious in the defensive withdrawal test (an animal model of anxiety) in rats. The synthesis, structure-activity relationships and in vivo properties of compounds within the pyrazinone chemotype are described.

The pneumotoxin 3-methylindole is a substrate and a mechanism-based inactivator of CYP2A13, a human cytochrome P450 enzyme preferentially expressed in the respiratory tract

3-Methylindole (3MI), a respiratory tract toxicant, can be metabolized by a number of cytochromes P450 (P450), primarily through either dehydrogenation or epoxidation of the indole. In the present study, we assessed the bioactivation of 3MI by recombinant CYP2A13, a human P450 predominantly expressed in the respiratory tract. Four metabolites were detected, and the two principal ones were identified as indole-3-carbinol (I-3-C) and 3-methyloxindole (MOI). Bioactivation of 3MI by CYP2A13 was verified by the observation of three glutathione (GSH) adducts designated as GS-A1 (glutathione adduct 1), GS-A2 (glutathione adduct 2), and GS-A3 (glutathione adduct 3) in a NADPH- and GSH-fortified reaction system. GS-A1 and GS-A2 gave the same molecular ion at m/z 437, an increase of 305 Da over 3MI. Their structures are assigned to be 3-glutathionyl-S-methylindole and 3-methyl-2-glutathionyl-S-indole, respectively, on the basis of the mass fragmentation data obtained by high-resolution mass spectrometry. Kinetic parameters were determined for the formation of I-3-C (V(max) = 1.5 nmol/min/nmol of P450; K(m) = 14 muM), MOI (V(max) = 1.9 nmol/min/nmol of P450; K(m) = 15 muM) and 3-glutathionyl-S-methylindole (V(max) = 0.7 nmol/min/nmol of P450; K(m) = 13 muM). The structure of GS-A3, a minor adduct with a protonated molecular ion at m/z 453, is proposed to be 3-glutathionyl-S-3-methyloxindole. We also discovered that 3MI is a mechanism-based inactivator of CYP2A13, given that it produced a time-, cofactor-, and 3MI concentration-dependent loss of activity toward 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, with a relatively low K(I) value of approximately 10 muM and a k(inact) of 0.046 min(-1). Thus, CYP2A13 metabolizes 3MI through multiple bioactivation pathways, and the process can lead to a suicide inactivation of CYP2A13.

Bioactivation of coumarin in rat olfactory mucosal microsomes: Detection of protein covalent binding and identification of reactive intermediates through analysis of glutathione adducts

The presence of high levels, as well as tissue-specific forms, of cytochrome P450 enzymes in mammalian olfactory mucosa (OM) has important implications in the bioactivation and toxicity of xenobiotics entering the tissue. Previous studies have shown that coumarin, a known olfactory toxicant in rats, is bioactivated by OM microsomal P450s to a number of products, presumably via coumarin-3,4-epoxide and other epoxide intermediates. The aim of the current study was to obtain direct evidence for the formation of such reactive intermediates in rat OM through the detection of protein covalent binding and glutathione (GSH) adduct formation. Protein covalent binding experiments with [(14)C]coumarin (10microM) displayed a 7-9-fold higher NADPH-dependent radioactivity binding in rat OM microsomes (2.5nmol/mg/30min) compared to those in rat and human liver microsomes; the binding value in rat OM microsomes was substantially but not completely reduced by the addition of GSH (5mM). LC/MS analyses detected a number of GSH adducts in GSH-supplemented coumarin metabolism reaction in rat OM microsomes; 3-glutathionyl coumarin was found to be the major one, indicating 3,4-epoxidation as the main bioactivation pathway. Additional GSH adducts were identified, presumably forming via the same pathway or epoxidation on the benzene moiety. Our findings provide direct evidence for the formation of multiple coumarin reactive intermediates in rat OM, leading to protein covalent binding and GSH conjugation.

Generation and characterization of a transgenic mouse model with hepatic expression of human CYP2A6

The aim of this study was to prepare and characterize a transgenic mouse model in which CYP2A6, a human P450 enzyme, is expressed specifically in the liver. CYP2A6, which is mainly expressed in human liver, is active toward many xenobiotics. Our transgene construct contained the mouse transthyretin promoter/enhancer, a full-length CYP2A6 cDNA, and a downstream neomycin-resistance gene for positive selection in embryonic stem cells. Hepatic expression of the CYP2A6 transgene was demonstrated by immunoblotting, whereas tissue specificity of CYP2A6 expression was confirmed by RNA-PCR. The transgenic mouse was further characterized after being backcrossed to the B6 strain for six generations. Hepatic microsomes from homozygous transgenic mice had activities significantly higher than those of B6 mice toward coumarin. The in vivo activity of transgenic CYP2A6 was also determined. Systemic clearance of coumarin was significantly higher in the transgenic mice than in B6 controls, consistent with the predicted role of CYP2A6 as the major coumarin hydroxylase in human liver. The CYP2A6-transgenic mouse model should be valuable for studying the in vivo function of this polymorphic human enzyme in drug metabolism and chemical toxicity.

Kinetics and regulation of cytochrome P450-mediated etoposide metabolism

Etoposide is a DNA topoisomerase II inhibitor widely used in the treatment of a variety of malignancies that is also associated with therapy-related leukemia. The cytochrome P450 (P450)-derived catechol and quinone metabolites of etoposide may be important in the damage to the MLL (mixed lineage leukemia) gene and other genes resulting in leukemia-associated chromosomal translocations. Kinetic analysis of catechol formation by recombinant P450s was determined using liquid chromatography/selected reaction monitoring/mass spectrometry. CYP3A4 was found to play a major role in etoposide metabolism (K(m) = 77.7 +/- 27.8 microM; V(max) = 314 +/- 84 pmol of catechol/min/nmol of P450). However, CYP3A5 (K(m) = 13. 9 +/- 3.1 microM; V(max) = 19.4 +/- 0.4 pmol of catechol/min/nmol of P450) may be involved in etoposide metabolism at therapeutic concentrations of free drug. Other P450s do not appear to be involved in etoposide catechol formation. Real-time polymerase chain reaction and Western blot analysis revealed significantly increased CYP3A4 mRNA and protein levels in hepatocytes treated with 10 microM rifampicin compared with untreated cells, but only modest effects of rifampicin on CYP3A5 induction. Etoposide (40, 5, 1, and 0.25 microM) caused a slight increase in CYP3A4 mRNA in three of five batches of hepatocytes but did not result in proportionately increased CYP3A4 protein levels. At high concentrations, etoposide induced only a modest increase in CYP3A5 mRNA and protein levels in four of five batches of hepatocytes. Alternatively, coadministration of other drugs with etoposide may account for the increase in etoposide catechol formation during therapy with etoposide.

Regulation of cytochrome P450 gene expression in the olfactory mucosa

The mammalian olfactory mucosa (OM) is unique among extrahepatic tissues in having high levels, and tissue-selective forms, of cytochrome P450 (CYP) enzymes. These enzymes may have important toxicological implications, as well as biological functions, in this chemosensory organ. In addition to a tissue-selective, abundant expression of CYP1A2, CYP2A, and CYP2G1, some of the OM CYPs are also known to have an early developmental expression, a resistance to xenobiotic inducers, and a lack of responsiveness to circadian rhythm. Efforts to fully characterize the regulation of CYP expression in the OM, and to identify the underlying mechanisms, are important for our understanding of the physiological functions and toxicological significance of these biotransformation enzymes, and may also shed unique light on the general mechanisms of CYP regulation. The aim of this mini-review is to provide a summary of current knowledge of the various modes of regulation of CYPs expressed in the OM, an update on our mechanistic studies on tissue-selective CYP expression, and a review of the literature on xenobiotic inducibility of OM CYPs. Our goal is to stimulate further studies in this exciting research area, which is of considerable importance, in view of the constant exposure of the human nasal tissues to inhaled, as well as systemically derived, chemicals, the prevalence of olfactory system damage in individuals with neurodegenerative diseases, and the current uncertainty in risk assessments for potential olfactory toxicants.

Targeted Disruption of the Olfactory Mucosa-SpecificCyp2g1Gene: Impact on Acetaminophen Toxicity in the Lateral Nasal Gland, and Tissue-Selective Effects onCyp2a5Expression

CYP2G1 is a cytochrome P450 monooxygenase expressed uniquely in the olfactory mucosa (OM). We have generated Cyp2g1-null mice to identify the roles of CYP2G1 in the biology and the tissue-specific toxicity of xenobiotic compounds in the nose. Homozygous Cyp2g1-null mice are viable and fertile; they show no evidence of embryonic lethality, morphological abnormality, or developmental deficits; and they seem to have normal olfactory ability. However, OM microsomes from Cyp2g1-null mice were found to have significantly lower activities than microsomes from wild-type mice in the metabolism of testosterone and progesterone (approximately 60% decrease) and in the metabolic activation of coumarin (>70% decrease). Unexpectedly, a significant reduction in the expression of the Cyp2a5 gene was found in the liver, the lateral nasal gland (LNG), and, to a lesser extent, the kidney of adult Cyp2g1-null mice. The loss of CYP2G1 expression, and the associated decrease in the hepatic expression of CYP2A5, did not decrease systemic clearance, extent of hepatotoxicity, or OM toxicity of acetaminophen (AP). However, the LNG was protected from AP (at 400 mg/kg) toxicity in the Cyp2g1-null mice. Paradoxically, the LNG did not have detectable CYP2G1, and the decrease in LNG CYP2A5 expression in the Cyp2g1-null mice was not accompanied by decreases in microsomal AP metabolism. We hypothesize that OM CYP2G1 (through a paracrine pathway) or LNG CYP2A5 may indirectly influence resistance of the LNG to chemical toxicity, possibly by regulating gene expression in the LNG through steroid hormones or other endogenous P450 substrates and their metabolites.

Conditional knockout of the mouse NADPH-cytochrome p450 reductase gene

NADPH-cytochrome P450 reductase (CPR or POR) is the obligatory electron donor for all microsomal cytochrome P450 (CYP or P450)-catalyzed monooxygenase reactions. Disruption of the mouse Cpr gene has been reported to cause prenatal developmental defects and embryonic lethality. In this study, we generated a mouse model with a floxed Cpr allele (termed Cpr(lox)). Homozygous Cpr(lox) mice are fertile and without any histological abnormality or any change in CPR expression. The floxed Cpr allele was subsequently deleted efficiently by crossing Cpr(lox) mice with transgenic mice having liver-specific Cre expression (Alb-Cre); the result was a decrease in the level of CPR protein in liver microsomes. The Cpr(lox) strain will be valuable for conditional Cpr gene deletion and subsequent determination of the impact of CPR loss on the metabolism of endogenous and xenobiotic compounds, as well as on postnatal development and other biological functions.

[The history of heroin abuse by assaying 6-monoacetylmorphine and morphine in human hair]

The purpose of this study is to conclude the history of heroin abuse by assaying 6-monoacetylmorphine (MAM) and morphine (MOR) in human hair. The hair of heroin abuse was labeled and segmented, then washed and cut into fragments. After hydrolyses and extraction, 6-MAM and MOR in human hair were determined by GC/MS-SIM with selected ion monitoring. Results of the segmented hair were analyzed. It provided useful information about the history of heroin abuse (hair growth rate 1-1.5 cm/mon).

Eotaxin and CCR3 are up-regulated in exacerbations of chronic bronchitis

BACKGROUND

Eosinophils and T lymphocytes represent constant features in the airways of subjects with exacerbated chronic bronchitis. Eotaxin is the most potent and selective eosinophil chemoattractant which can also attracts lymphocytes. The aim of the study was to evaluate the expression of eotaxin and its receptor, CCR3, in bronchial airways during exacerbation of chronic bronchitis.

METHODS

By immunohistochemistry we studied eotaxin and CCR3 expression in the lamina propria of 14 subjects with acute exacerbation of chronic bronchitis. 20 asthmatics, and 8 healthy subjects. We determined the cell types expressing the CCR3 receptor by colocalization experiments. We finally studied the relationship between eotaxin and CCR3 and eosinophils and T lymphocytes.

RESULTS

The number of eotaxin+ and CCR3+ cells was significantly higher in exacerbated chronic bronchitis (P<0.003 and P<0.002) and asthma (P<0.002 and P<0.0001) when compared to healthy subjects. CCR3 was mainly expressed by eosinophils and to a lesser extent by CD4+ and CD8+ lymphocytes. In exacerbated chronic bronchitis the number of CCR3+ cells was strongly correlated to the number of eosinophils (P<0.0002. r=0.85) and to the number of CD4+ lymphocytes (P<0.05, r=0.57).

CONCLUSION

Our study suggests that eotaxin and CCR3 are up-regulated and could be involved in the eosinophil and CD4+ lymphocyte recruitment into the airways which occur during acute exacerbations of chronic bronchitis.

[Construction of eukaryotic expression plasmid pcDNA3-gtfB expressing glucosyltransferase B of Streptococcus mutans]

OBJECTIVE

Glucosyltransferase (GTF) of Streptococcus mutans is considered as a cariogenic virulence factor due to its ability to synthesize glucan, which facilitate sucrose-depended adherence and cell-to-cell accumulation of bacteria. In this study, gtfB, the target gene fragment which encodes multiple catalytic sites and antigen epitopes of GTF, was recombined into eukaryotic expression vector pcDNA3. The feasibility of the recombination plasmid pcDNA3-gtfB used as gene vaccine will be investigated in further study.

METHODS

The target gene fragment gtfB (904-4578 bp) was obtained by standard PCR amplification while genome DNA of streptococcus mutans GS-5 was used as template. Then the PCR products were extracted and purified from low-melting temperature agarose. The gtfB and plasmid pcDNA3 were cut by Kpn I, Xho I, and the digested products were extracted and purified again for recombination. The purified gtfB and plasmid pcDNA3 were recombined by T4 DNA ligase, ligation products were transformed into competent cell, Escherichia coli JM109. Transformed colonies were screened by Ampr LB plate, then recombined plasmids were isolated and identified by restricted endonuclease cutting and Sanger dideoxy DNA sequencing.

RESULTS

Identified by agarose gel electrophoresis, the target gene-gtfB obtained PCR amplification had the same molecular size (36 kb) as predicted. It was indicated that recombined plasmids contained inserted gtfB gene fragment by restricted endonuclease cut analysis, the sequencing data also indicated that inserted gtfB gene had correct DNA sequence and orientation according to DNA sequence of Streptococcus mutans GS-5 (gene bank M17361).

CONCLUSION

Inserted gene-gtfB of recombined plasmid pcDNA3-gtfB encoded multiple catalytic sites and epitopes. It was proved that these epitopes had high immune antigenicity and that antiserum could significantly inhibit the synthesis of water-insoluble glucans and water-soluble glucan. In vitro adherence experiment also indicated that it could inhibit streptococcus mutans adherence to saliva-coated hydroxyapatite. Vector pcDNA3 was high expressing eukaryotic vector, and could stimulate antigen-representing cell. It was suggested that recombined plasmid pcDNA3-gtfB had high immune antigenicity and immune responsiveness, and this supported its use as gene vaccine candidates in the development of anti-caries vaccines.

Mouse cyp2g1 gene: promoter structure and tissue-specific expression of a cyp2g1-lacz fusion gene in transgenic mice

The structure of the mouse Cyp2g1 gene was determined to identify regulatory regions important for its olfactory mucosa-specific expression. Two Cyp2g1 genomic clones were isolated and characterized. A 3.6-kilobase 5'-flanking sequence was used to prepare a Cyp2g1--LacZ fusion gene for transgenic mice production. Transgene expression, as determined by beta-galactosidase activity in tissue extracts, was detected in the olfactory mucosa, but not in any other tissues examined, in five different transgenic lines. Thus, the 3.6-kilobase fragment contained regulatory elements sufficient for olfactory mucosa-specific and proper developmental expression of the reporter gene. However, histological and immunohistochemical studies indicated that the expression of the transgene in the olfactory mucosa was patchy and the cellular expression patterns of the transgene did not exactly match that of the endogenous gene. These results implicate the presence of additional regulatory sequences that are necessary for the correct cell type-selectivity within the olfactory mucosa.

NADPH- and hydroperoxide-supported 17beta-estradiol hydroxylation catalyzed by a variant form (432L, 453S) of human cytochrome P450 1B1

Human cytochrome P450 1B1 (CYP1B1) catalyzes the hydroxylation of 17beta-estradiol (E(2)) at C-4, with a lesser activity at C-2. The E(2) 4-hydroxylase activity of human CYP1B1 was first observed in studies of MCF-7 breast cancer cells. Sequencing of polymerase chain reaction products revealed that CYP1B1 expressed in MCF-7 cells was not the previously characterized enzyme but a polymorphic form with leucine substituted for valine at position 432 and serine substituted for asparagine at position 453. To investigate the NADPH- and organic hydroperoxide-supported E(2) hydroxylase activities of the 432L, 453S form of human CYP1B1, the MCF-7 CYP1B1 cDNA was cloned and the enzyme was expressed in Sf9 insect cells. In microsomal assays supplemented with human NADPH:cytochrome P450 oxidoreductase, the expressed 432L, 453S form catalyzed NADPH-supported E(2) hydroxylation with a similar preference for 4-hydroxylation as the 432V, 453N form, with maximal rates of 1.97 and 0.37 nmol (min)(-1)(nmol cytochrome P450)(-1) for 4- and 2-hydroxylation, respectively. Cumeme hydroperoxide efficiently supported E(2) hydroxylation by both the 432V, 453N and 432L, 453S forms at several-fold higher rates than the NADPH-supported activities and with a lesser preference for E(2) 4- versus 2-hydroxylation (2:1). The hydroperoxide-supported activities of both forms were potently inhibited by the CYP1B1 inhibitor, 3,3',4, 4',5,5'-hexachlorobiphenyl. These results indicate that the 432V, 453N and 432L, 453S forms of CYP1B1 have similar catalytic properties for E(2) hydroxylation, and that human CYP1B1 is very efficient in catalyzing the hydroperoxide-dependent formation of catecholestrogens.

[Total cavo-pulmonary connection for complex congenital heart disease]

Between April 1994 and January 1997, 10 patients with complex congenital heart disease were treated with total cavo-pulmonary connection(TCPC). They included 7 males and 3 females, aged 2-17 years(mean 10.1 years). These cases were single ventricle in 5, tricuspid atresia in 4, severe Ebstein anomaly in 1. For construction of the right atrial lateral tunnel, Gore-Tex patch was used in 9 cases and autologous right atrial wall in another, 4 of the 10 patients underwent TCPC without aortic crossclamping. There were no operative deaths. The follow-up is 2-36 months(mean 12.3 months). All of these patients did well and were in NYHA class I. The advantages, operative indication and technique of TCPC and the experience of improvement of surgical results are briefly discussed in this paper.

The increased number of very late activation antigen-4-positive cells correlates with eosinophils and severity of disease in the induced sputum of asthmatic patients

BACKGROUND

Lymphocyte function associate-1 (LFA-1), macrophage antigen-1 (Mac-1), and very late activation antigen-4 (VLA-4) are involved in the infiltration of leukocytes into the tissues. Experimental models of allergic inflammation suggest that VLA-4 could determine the selective recruitment of eosinophils into the inflamed airways.

OBJECTIVE

Our purpose was to evaluate the involvement of integrins in eosinophil recruitment in asthma.

METHODS

We evaluated by immunocytochemistry the expression of VLA-4, LFA-1, and Mac-1 and their relationship with inflammatory cells and severity of disease in the induced sputum of 20 mild to moderate atopic asthmatic subjects and in 8 healthy subjects.

RESULTS

The number of VLA-4+ cells is increased in asthmatic patients and VLA-4 is mainly localized on eosinophils. Furthermore, VLA-4+ cells are significantly related to eosinophils. In contrast, LFA-1 and Mac-1 cellular expressions do not differ between asthmatic and control subjects and are not related to any specific cell type. Eosinophils and VLA-4+ cells are significantly higher in moderately compared with mildly asthmatic patients (P <.01, P <.05) and with healthy control subjects (P <.0005, P <.001). Eosinophils and VLA-4+ cells are also higher in mildly asthmatic patients compared with control subjects (P <.001, P <.005).

CONCLUSION

This is the first report demonstrating, by a noninvasive method in humans, that VLA-4+ cells are increased and correlate with the eosinophils in the induced sputum of atopic patients with mild to moderate asthma and that VLA-4 expression is related to the severity of disease.

[Determination of basic drugs in blood by RP-HPLC]

A reversed-phase HPLC method for determination of phenothiazines and tricyclin antidepressants in whole blood was described. In this paper, a model 1090 HPLC with DAD and a zorbax ODS column was used. The mobile phase was methanol: water: tritely amine (75:24.7:0.3) with pH 7.5. Cyproheptadine was used as internal standard in this method. Blood samples were extracted with the solid-phase extraction method and the liquid-liquid method. This method is suitable in forensic toxicology analysis for basic drugs.

Biotransformation of coumarin by rodent and human cytochromes P-450: metabolic basis of tissue-selective toxicity in olfactory mucosa of rats and mice

Coumarin was previously found to cause tissue-selective toxicity in the olfactory mucosa (OM) of rats and mice, with rats being the more sensitive species. The aim of this study was to explore the role of target tissue biotransformation in OM-selective toxicity and the metabolic basis of the species differences in coumarin toxicity. At least six coumarin metabolites were detected in OM microsomal reactions, with o-hydroxyphenylacetaldehyde (o-HPA) being the most abundant. Formation of o-HPA was inhibited by reduced glutathione, confirming its origin from a reactive intermediate. There were significant differences in the rates and metabolite profiles of coumarin metabolism in the livers of Wistar rats and C57BL/6 mice. The rates of metabolic activation of coumarin, as indicated by the formation of o-HPA, were comparable in OM microsomes of the two species but about 25- and 3-fold higher in OM than in liver microsomes of rats and mice, respectively. Thus, target tissue activation seems to play an important role in the tissue-selective toxicity, whereas differences in the rates of hepatic metabolism may be responsible for the species difference in olfactory toxicity. Purified, heterologously expressed mouse CYP2A5 and CYP2G1 produced 7-hydroxycoumarin and o-HPA as the predominant products, respectively. Kinetic analysis and immunoinhibition studies indicated that the OM-specific CYP2G1 plays the major role in metabolic activation of coumarin. Furthermore, of 13 human cytochrome P-450s (P-450s) examined, five (CYP1A1, CYP1A2, CYP2B6, CYP2E1, and CYP3A4) were active in the metabolic activation of coumarin, suggesting a potential risk of coumarin toxicity in humans.

[Detection of heroin metabolites: 6-monoacetylmorphine and morphine in human hair by GC/MS]

This paper presents a method to detect the main metabolites of heroin: 6-monoacetylmorphine (6-MAM) and morphine (MOR) in human hair using GC/MS-SIM. The hair specimens were washed with special solvents and cut into about 0.5 mm pieces. Ethylmorphine was added as internal standard and HCl solution for hydrolysis. After hydrolysis, 6-MAM and MOR were extracted by a mixture of solvents (chloroform-isopropyl alcohol-heptane 50:17:33). The residue of the extract was derivatized with N-methyl-N-trimethylsilyl trifluoroacetamide(MSTFA), then the trimethylsilyl(TMS)-derivatives were qualitatively and quantitatively analyzed using GC/MS-SIM. The correlation coefficients for 6-MAM and MOR were 0.9996 and 0.9997, respectively. The recoveries of both 6-MAM and MOR were over 50%. The RSD of within-day and between-day was less than 8% and 10%, respectively. The lower limit of detection of both 6-MAM and MOR was 0.5 ng.mg-1. Hair samples of 12 drug abusers were analyzed using this method, 8 of them gave positive results. This method is simple, accurate and sensitive. It is very suitable for routine case work.

Heat shock protein 70 upregulation is related to HLA-DR expression in bronchial asthma. Effects of inhaled glucocorticoids

BACKGROUND AND OBJECTIVE

Antigen processing determines the production of peptides from antigens - including allergens - and their binding to class II major histocompatibility complex molecules, that stimulate T-cell responses. Heat shock protein (hsp) 70 are recognized to have a role in chaperoning antigenic peptides and in facilitating class II peptide assembly. We studied the HLA-DR and hsp70 expression on BAL cells and bronchial biopsies from asthmatics, as well as the effect of low dose fluticasone propionate treatment.

METHODS

Twenty-three asthmatics and eight normal subjects were selected. In each subject BAL and bronchial biopsies were performed. Eighteen out of 23 asthmatics, underwent the second bronchoscopy after 6 weeks of low dose inhaled fluticasone propionate treatment (250 microg b.d.) in a placebo-controlled double-blind study. BAL fluid and biopsies were processed to evaluate HLA-DR and hsp70 expression by immunochemistry methods.

RESULTS

Hsp70 and HLA-DR upregulation was present on professional and non-professional antigen presenting cells (APCs). In asthmatics, the hsp70 and HLA-DR expression was higher in BAL (hsp70 P<0.001, HLA-DR P<0.001) and bronchial epithelium (hsp70 P<0.001, HLA-DR P<0.001) when compared with controls. We also observed a significant correlation between hsp70 and HLA-DR expression in BAL (P<0.005) and epithelium (P<0.001). Fluticasone propionate treatment down-regulated the hsp70 and HLA-DR expression in BAL (hsp70 P < 0.001, HLA-DR P < 0.05) and bronchial epithelium (hsp70 P < 0.05, HLA-DR P < 0.05). A serial section comparison study showed that CD1a+ cells and macrophages were positive for both hsp70 and HLA-DR in the submucosa.

CONCLUSIONS

Our results support the hypothesis that hsp70 over-expression implies a potential role for these proteins in antigen processing and/or presentation resulting in an increased activity of APCs, which is essential for the initiation and modulation of the asthmatic immune response in chronic asthma. Fluticasone propionate induces downregulation of HLA-DR and hsp70 molecules thus regulating inflammation by affecting key mechanisms of the allergic response.

[Decomposition kinetics of methamidophos in preserved blood of rabbit]

Decomposition kinetics of methmidophos in preserved rabbit blood poisoned by methamidophos was studied. The blood was preserved in a room (temperature 12-15 degrees C) and in a refrigerator (temperature 2-5 degrees C). The concentration of methamidophos in preserved blood was determined by GC/FPD. The results showed that the decomposition of methamidophos in preserved blood of rabbits was fast for the first three days and got slow with the time prolonged. The decomposition speed of methamidophos in room was higher than in refrigerator.

Short-term treatment with a low dose of inhaled fluticasone propionate decreases the number of CD1a+ dendritic cells in asthmatic airways

The activation of T-lymphocytes through the recognition of specific allergens is a crucial event in the development of allergic inflammation. Dendritic cells (DC) are potent accessory cells that play an important role in initiating bronchial immune responses by activation of T-lymphocytes. We investigated the distribution of CD1a+ DC in the bronchial biopsies from asthmatic patients, and evaluated the effects of a short course of low dose inhaled fluticasone propionate treatment. Twenty-three mild to moderate stable asthmatic patients and eight normal subjects were included in the study. Bronchoscopy with bronchial biopsies were performed in each subject. Eighteen of the 23 asthmatics underwent a second bronchoscopy after 6 weeks of low dose inhaled fluticasone propionate treatment (250 mcg bd) in a placebo-controlled double-blind study. Biopsies were embedded into glycolmethacrylate resin and analysed by immunohistochemistry methods using specific monoclonal antibodies against CD1a, which is a widely recognized marker for DC. In asthmatics, CD1a+ DC number was significantly higher in bronchial epithelium (P < 0.001) and in lamina propria (P < 0.001) when compared with normal controls. In addition, we observed that a short course of low dose inhaled fluticasone propionate treatment decreased the number of CD1a+ DC in both the bronchial epithelium (P < 0.05) and lamina propria (P < 0.01). The increased number of CD1a+ DC support the hypothesis that DC play an important role in the modulation of the immune response in chronic asthma. Short-term low dose fluticasone propionate treatment induces down-regulation of the CD1a+ DC number.