Determination of PNU-248686A, a novel matrix metalloproteinase inhibitor, in human plasma by liquid chromatography-tandem mass spectrometry, following protein precipitation in the 96-well plate format

A sensitive, specific and high-throughput analytical method for the quantitation of PNU-248686A (I), in human plasma has been developed. I, sodium (2R)-3-[[(4'-chloro(1,1'-biphenyl)-4-yl]sulfonyl]-2-hydroxy-2-[(phenylsulfanyl)methyl] propanoate, is an orally active matrix metalloproteinase (MMP) inhibitor developed for the treatment of solid tumors over-expressing MMPs. Concentrations of I, as free acid, were determined in human plasma by LC-MS-MS after plasma protein precipitation in the 96-well plate format. Aliquots of plasma (50 microl) were placed into the plates and 0.2 ml of methanol was added. The plates were shaken for 5 min and centrifuged at 1500 g for 10 min. Aliquots of 10 microl of the supernatants were then directly injected into the LC-MS-MS system. A Symmetry Shield C. column (50 x 2.1 mm, 3.5 microm) was used to perform the chromatographic analysis. The mobile phase was 5 mM ammonium formate buffer solution pH 5.0-acetonitrile (60:40. v/v) with a flow-rate of 0.3 ml/min. Retention time of I was about 1.2 min. Total cycle time was 2.5 min. MS detection used the Applied Biosystems-MDS Sciex API 3000 with TurbolonSpray interface and single reaction monitoring (461 --> 251 m/z transition) operated in negative ion mode. Calibration curves were constructed by plotting the area of the compound (y) against its concentration (x). A weighed linear regression (weighting factor 1/x(2)) was used to calculate I concentrations in quality control and unknown samples. The method was fully validated over the range of 5.0-5000 ng/ml. The suitability and robustness of the method for in vivo samples was confirmed by analysis of plasma samples from a pilot clinical study.

Changes in serum and histology of patients with chronic hepatitis B after interferon alpha-2b treatment

AIM: Chronic hepatitis B is a serious health problem. Interferon has long been used to treat Chronic hepatitis B. To evaluate the effects of interferon on chronic hepatitis B better, we designed the study to investigate the changes in sera and liver histology of patients with chronic hepatitis B after interferon alpha-2b treatment.

METHODS: Twenty-four patients with chronic hepatitis B were enrolled in this study. They all received interferon alpha-2b treatment as following: 3 million units, i.m. t.i.w., for 18 weeks. Sera of all patients were obtained respectively for evaluation of ALT, HBsAg, HBcAg, HBeAg, HBV DNA and TIMP-1 before and after interferon treatment, also a liver biopsy pre- and post-treatment was performed for comparison of HAI, HBsAg, HBcAg, HBeAg, TIMP-1 and activated HSC in the liver tissue.

RESULTS: Patients who had normalization of serum ALT and seroconversion of HBeAg and/or HBV DNA (blot hybridization) after treatment were defined as responders. The response rate in this study group was 37.5% (7/24). Compared to pretreatment, the serum HBV DNA and TIMP-1 decreased significantly (P < 0.05), so did the HAI, HBcAg, HBeAg, TIMP-1 and activated HSC (P < 0.05).

CONCLUSION: The significant decrease in HBV DNA in sera, the seroconversion of HBeAg, and the decrease of viral expression in liver indicated that interferon alpha-2b treatment can inhibit viral replication. The normalization of ALT in sera and the improvement of HAI in liver showed that interferon alpha-2b can improve the liver histology of patients with chronic hepatitis B. At the same time, interferon alpha-2b treatment can reduce the TIMP-1 in serum and liver and decrease the number of activated HSC, which may allievate or inhibit hepatic fibrosis. Although the response rate was unsatisfactory, interferon play a benefical role on patients with chronic hepatitis B in other respects. We still need further studies to improve the therapy effects.

Successful treatment of a young infant who developed high-titer inhibitors against VWF-cleaving protease (ADAMTS-13): important discrimination from Upshaw-Schulman syndrome

We report herein the case of a 9-month-old female infant with acquired thrombotic thrombocytopenic purpura (TTP), which was initially suspected to be either Upshaw-Schulman syndrome (USS or a congenital TTP) or hemolytic uremic syndrome (HUS) because of onset of clinical signs in infancy and accompanying diarrhea. She received combination therapy of plasma exchange, steroid pulse, and high-dose intravenous immunoglobulin infusion that was initiated before the definitive diagnosis, which resulted in excellent clinical improvement. The retrograde analysis of plasma ADAMTS-13 activity and its inhibitor showed a lack of this enzyme activity and the presence of a high-titer IgG inhibitor (200-320 Bethesda units/mL) to this enzyme activity. From our experience, it was suggested that we should recognize the possibility of the patient with acquired TTP in infancy and the importance of plasma exchange therapy for management of its clinical symptoms.

Evidence for dissolution rate-limited absorption of COL-3, a matrix metalloproteinase inhibitor, leading to the irregular absorption profile in rats after oral administration

PURPOSE

This study was undertaken to elucidate the underlying mechanism of the irregular absorption profiles of COL-3, a matrix metalloproteinase inhibitor, with a double- or plateau-peak concentration after a single oral dose administration of COL-3 suspension to rats.

METHODS

The gastrointestinal absorption profiles of COL-3 in rats were assessed by comparing serum drug concentration curves after the following various modes of drug administration: oral and intraduodenal doses, oral doses of COL-3 in fine and coarse suspensions, intraduodenal dosing to the bile-duct intact and cannulated (BDC) rats, and oral doses with and without food. In addition, the biliary excretion of COL-3 in the BDC rats was examined.

RESULTS

Neither variable gastric emptying nor enterohepatic recycling was the source of the irregular gastrointestinal absorption of COL-3 in rats. Reduction in particle size, presence of food and endogenous bile emerged as the determinants of the oral absorption of COL-3 by enhancing the dissolution of the solid drug in the gastrointestinal fluids. Flip-flop of the absorption and elimination rate constants was noted only for COL-3 after intraduodenal administration of the coarse suspension to the BDC rats with the bile flow diverged out of the body.

CONCLUSIONS

Variability in dissolution rate-limited absorption was the main cause of the irregular absorption of COL-3 after oral administration of its solid dosage form.

Increased Trypanosoma cruzi invasion and heart fibrosis associated with high transforming growth factor beta levels in mice deficient in alpha(2)-macroglobulin

Trypanosoma cruzi proteinases are involved in host cell invasion in human patients and in mouse models. In mice, murine alpha(2)-macroglobulin (MAM) and murinoglobulin are circulating plasma proteinase inhibitors that also have important roles in inflammation and immune modulation. To define their role in experimental Chagas disease, we investigated the susceptibility to T. cruzi infection of mice that are deficient only in alpha2-macroglobulins (AM-KO) or in both MAM and monomeric murinoglobulin-1 (MM-KO), relative to the wild type (WT). Despite the high parasite load, parasitemia was lower in AM-KO and MM-KO mice than in WT mice. Nevertheless, we observed a significantly higher parasite load in the hearts of AM-KO and MM-KO mice, i.e., more amastigote nests and inflammatory infiltrates than in WT mice. This result demonstrates a protective role for MAM in the acute phase of murine T. cruzi infection. We further demonstrated in vitro that human alpha2-macroglobulins altered the trypomastigote morphology and motility in a dose-dependent way, and that also impaired T. cruzi invasion in cardiomyocytes. Finally, we demonstrated that the levels of transforming growth factor beta in AM-KO mice increased significantly in the third week postinfection, concomitant with high amastigote burden and important fibrosis. Combined, these in vivo and in vitro findings demonstrate that the MAM contribute to the resistance of mice to acute myocarditis induced by experimental T. cruzi infection.

Gut barrier permeability, reticuloendothelial system function and protease inhibitor levels following intestinal ischaemia and reperfusion--effects of pretreatment with N-acetyl-L-cysteine and indomethacin

BACKGROUND

Pathophysiological mechanisms and ways to intervene on intestinal barrier dysfunction following small intestinal ischaemia and prolonged reperfusion are still not fully clarified.

AIMS

To evaluate the effect of oxygen free radical and prostaglandin inhibition on intestinal barrier injury following intestinal ischaemia/reperfusion.

METHODS

Endothelial and epithelial barrier permeability was evaluated by clearance of radiolabelled albumin. Parameters included 125I-Escherichia coli uptake rate index, host reticuloendothelial system function and organ distribution, as well as protease inhibitor and proenzyme activities in rats subjected to small intestinal ischaemia for 40 minutes followed by 12 hours reperfusion (ischaemia/reperfusion), pretreated with N-acetyl-L-cysteine or indomethacin.

RESULTS

Following ischaemia/reperfusion, endothelial and epithelial permeability increased, reticuloendothelial system activation occurred and plasma protease inhibitors were consumed. N-acetyl-L-cysteine pretreatment resulted in improved endothelial and epithelial barrier integrity, a decrease in protease inhibitor consumption and less pronounced reticuloendothelial system activation. Pretreatment with indomethacin was not effective.

CONCLUSION

Oxygen free radicals seem to play an important role in the development of intestinal barrier impairment following ischaemia/reperfusion. N-acetyl-L-cystine may be a potential agent for preventing ischaemia/reperfusion damage.

Pyrrolidine-5,5-trans-lactams as novel mechanism-based inhibitors of human cytomegalovirus protease. Part 3: potency and plasma stability

Mechanism-based inhibitors of HCMV protease, which are stable to human plasma (> or = 20 h) and have single-figure potency in the microM range against HCMV protease, have been developed based on the dansylproline alpha-methyl pyrrolidine-5,5-trans-lactam nucleus.

Matrix metalloproteinase-9 and tissue inhibitors of matrix metalloproteinase-1 in plasma of patients co-infected with HCV and HIV

BACKGROUND

Accelerated progression of hepatic fibrosis has been shown in patients co-infected with hepatitis C virus (HCV) and HIV. Liver fibrosis is a dynamic process in which the altered balance between matrix metalloproteinases (MMPs) and their specific inhibitors (TIMPs) may play a major role.

METHOD

The involvement of MMP-9 and TIMP-1 in HCV liver disease progression in patients co-infected with HIV was evaluated. Plasma concentrations of human MMP-9 and TIMP-1 were assessed in 76 HIV-infected patients; 27 were co-infected with HCV and 49 were HCV negative. 18 healthy donors were included as controls.

RESULTS

Patients with HIV infection exhibited a striking increase in TIMP-1 levels; this is more evident in patients with advanced CD4 depletion. There was no elevation in the plasma concentrations of the MMP-9. The highest levels of TIMP-1 were found in the HIV/HCV co-infected patients. The values of TIMP-1 in HIV-infected patients with chronic HCV hepatitis were significantly higher than in HIV-positive individuals without HCV infection, even including those with low CD4 count. No significant differences were seen in the MMP-9 levels.

CONCLUSION

These findings suggest that the altered balance between circulating MMP-9 and TIMP-1 during HIV infection may play an important role in exacerbating liver fibrosis progression in patients co-infected with HCV.

The effect of intestinal ischemia and reperfusion injury on ICAM-1 expression, endothelial barrier function, neutrophil tissue influx, and protease inhibitor levels in rats

Multiple organ dysfunction syndrome (MODS) is mediated by complex mechanisms in which interactions between activated leukocytes and endothelial cells play a central role. ICAM-1 (intercellular adhesion molecule-1) mediates firm adhesion and transendothelial migration of activated leukocytes from postcapillary venules into the tissue. The present study evaluated the ICAM-1 expression in various organs after 40 min of intestinal ischemia and 1, 3, 6, 12 h of reperfusion (I/R) in the rat, using a dual monoclonal antibody technique (n = 36). Endothelial barrier permeability, using the vascular leakage of radiolabeled human serum albumin was also assessed (n = 12). Neutrophil sequestration in the lungs was quantitated by myeloperoxidase activity and plasma protease inhibitor levels were measured with electroimmunoassay. Significant regional differences were found in ICAM-1 expression between organs, both constitutively and after I/R-injury. The highest constitutive levels were observed in the liver and lungs, followed by the kidneys. The constitutive ICAM-1 expression in the intestines and in the heart was about 1/20 compared with that found in the liver and lungs. The brain and muscle had levels of about 1/150 of that in the liver and lungs. After intestinal I/R, significant increases (17-45%) were found in the lungs, intestines, brain, heart, and muscle. Albumin leakage index (ALI) in all examined organs and myeloperoxidase activity in the lungs increased after I/R-injury. Serum levels of albumin and most protease inhibitors decreased significantly after I/R challenge. Intestinal I/R results in an increase of systemic ICAM-1 expression with marked organ variability. The upregulation of ICAM-1 could represent a crucial step in the adherence- and migration process of activated leukocytes and potentially in the development of tissue injury.

Effective treatment of gut barrier dysfunction using an antioxidant, a PAF inhibitor, and monoclonal antibodies against the adhesion molecule PECAM-1

BACKGROUND

Oxygen free radicals (OFRs), platelet activating factor (PAF), cell adhesion molecules, and transmigration of polymorphonuclear leukocytes through the gut barrier are probably all essential in the development of gut barrier dysfunction following intestinal ischemia and reperfusion (I/R). Pretreatment and early treatment of I/R with the OFRs-scavenger (NAC), the PAF inhibitor lexipafant, and monoclonal antibodies against the adhesion molecule PECAM-1 (anti-PECAM-1-Mab) have been reported to be effective in the prevention or recovery of gut barrier dysfunction and result in a decrease in cytokine levels. Less is known about the effect of treatment inserted during the late stage of I/R. The objective of this study was to evaluate the potential therapeutic value of single or combination therapy with NAC, lexipafant, and anti-PECAM-1-MAb administered late during intestinal I/R in the rat.

METHODS

NAC, lexipafant, and anti-PECAM-1-MAb were administrated, alone or in combination, after 3 h of reperfusion following 40 min of superior mesenteric arterial ischemia in the rat. Intestinal endothelial and epithelial barrier permeability, myeloperoxidase (MPO) activity, interleukin-1 beta (IL-1 beta), and protease inhibitor levels were evaluated after 12 h of reperfusion.

RESULTS

Intestinal endothelial and epithelial permeability significantly increased in rats with I/R and saline treatment. Proteolytic activity in plasma was indicated by low levels of the three measured plasma protease inhibitors. Intestinal mucosal MPO content increased significantly. These changes were, to different degrees, reduced by late inserted treatment with NAC, lexipafant, or anti-PECAM-1-MAb. Alterations in systemic levels of IL-1 beta paralleled the changes found in gut barrier permeability and leukocyte trapping. Systemic antithrombin III levels and increased barrier permeability in remote organs were partly restored, especially by multimodal therapy.

CONCLUSION

Treatment with NAC, lexipafant, and/or monoclonal antibodies against PECAM-1, inserted at a later stage of I/R, reduced the severity of I/R-associated intestinal dysfunction and decreased the systemic concentrations of IL-1 beta, local leukocyte recruitment (MPO), and partly restored plasma protease inhibitor levels.

Critical issues in therapeutic drug monitoring of antiretroviral drugs

The interest in therapeutic drug monitoring (TDM) of antiretroviral drugs is growing rapidly. For the protease inhibitors, and to a lesser extent for the non-nucleoside reverse transcriptase inhibitors, relationships between plasma drug concentrations and their efficacy and toxicity have been identified. Furthermore, the pharmacokinetics of especially the protease inhibitors vary widely between patients, suggesting a role for TDM to individualize antiretroviral therapy. Recently, randomized, prospective clinical trials evaluating the role of TDM in the management of HIV-1-infected patients showed promising results. However, there are still many questions to be answered before large-scale introduction of TDM can be justified (e.g., which pharmacokinetic parameter should be optimized, and what is the minimal effective concentration). This review summarizes the basis for TDM of antiretroviral drugs and discusses the problems and prospects of this potential tool in the care for HIV-1-infected individuals.

High-performance liquid chromatographic method for the simultaneous determination of the six HIV-protease inhibitors and two non-nucleoside reverse transcriptase inhibitors in human plasma

A selective and sensitive high-performance liquid chromatographic (HPLC) method has been developed for the determination of the six human immunodeficiency virus (HIV)-protease inhibitors (amprenavir, indinavir, lopinavir, nelfinavir, ritonavir, and saquinavir) and the non-nucleoside reverse transcriptase inhibitors (efavirenz and nevirapine) in a single run. After a liquid-liquid extraction with diethyl ether, the six protease inhibitors and the two non-nucleoside reverse transcriptase inhibitors are separated on a Stability RP18 column eluted with a gradient of acetonitrile and phosphate buffer 50 mmol/L pH 5.65. A sequential ultraviolet detection (5-minute sequence set at 240 nm for nevirapine acquisition, 22-minute sequence set at 215 nm for other antiretroviral drugs acquisition followed by a sequence set at 260 nm for internal standard acquisition) allowed for simultaneous quantitation of the six protease inhibitors, nevirapine, and efavirenz. Calibration curves were linear in the range 100 ng/mL to 10,000 ng/mL. The limit of quantitation was 50 ng/mL for all drugs except nevirapine (100 ng/mL). Average accuracy at four concentrations ranged from 88.2% to 110.9%. Both interday and intraday coefficients of variation were less than 11% for all drugs. The extraction recoveries were greater than 62%. This method is simple and shows a good specificity with respect to commonly co-prescribed drugs. This method allows accurate therapeutic monitoring of amprenavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir, efavirenz, and nevirapine.

[Effects of immunization on proteinase-inhibitor balance in the lacrimal fluid and blood serum in alkaline burns of the cornea (an experimental study)]

Proteinase-inhibitor balance in the lacrimal fluid in eye burns was studied in rabbits with modified and intact immune status. Stimulation of the immune system was induced by complete Freund's adjuvant. Clinical picture of the disease was studied in parallel. Immunization accelerated the local adaptive and defense reaction of the proteolytic enzymes and their inhibitors, which was paralleled by a more benign course of burn disease of the eyes, in comparison with that in non-immunized animals.

Combined inhibition of neutral endopeptidase with angiotensin converting enzyme or endothelin converting enzyme in experimental diabetes

OBJECTIVE

The effects of combined inhibition of neutral endopeptidase (NEP) with either angiotensin-converting enzyme (ACE), or endothelin-converting enzyme (ECE) on blood pressure, urinary albumin excretion and heart weight were explored in experimental diabetes.

DESIGN

Streptozotocin-induced diabetic Sprague-Dawley rats were treated with vehicle, the NEP/ACE inhibitor S 21402, the NEP/ECE inhibitor CGS 26303, the NEP inhibitor SCH 42495, the ACE inhibitor captopril or the endothelin receptor antagonist bosentan for 4 weeks.

METHODS

Blood pressure was measured by tail-cuff method and radiotelemetry. Albuminuria, plasma renin activity and plasma atrial natriuretic peptide (ANP) were determined by radioimmunoassay. NEP binding was assessed by in vitro quantitative autoradiography. Metabolic and biochemistry parameters including food intake, 24-h urine volume, plasma glucose, glycated hemoglobin, glomerular filtration rate (GFR) and urinary sodium excretion were also determined.

RESULTS

Mean blood pressure over the 4-week study period after commencement of treatment was reduced to a similar extent by a range of treatments including the ACE inhibitor, NEP/ACE inhibitor, endothelin receptor antagonist, NEP/ECE inhibitor, but not the NEP inhibitor, compared with vehicle-treated diabetic rats. Heart to body weight ratio in diabetic rats was only reduced by the NEP/ACE and the NEP/ECE inhibitor. Increased albuminuria in diabetic rats (1.1 times/divided by 1.2 mg/day) was reduced by the NEP/ACE (0.6 times/divided by 1.2 mg/day) and the NEP/ECE inhibitors (0.4 times/divided by 1.2 mg/day). Renal NEP was reduced by the NEP/ACE inhibitor (35 +/- 4%) or NEP/ECE inhibitor (38 +/- 4%) as well as by the pure NEP inhibitor (27 +/- 4%) compared with the untreated diabetic group. Other abnormal metabolic and biochemical parameters in diabetic rats were not influenced by any drug treatment.

CONCLUSIONS

Combined inhibition of NEP/ACE or NEP/ECE confers beneficial effects on blood pressure, albuminuria and heart to body weight ratio in experimental diabetes.

In electrospray ionization source hydrogen/deuterium exchange LC-MS and LC-MS/MS for characterization of metabolites

A new method is described for performing hydrogen/deuterium (H/D) exchange in an electrospray ionization (ESI) source. The use of liquid chromatography (LC)-mass spectrometer equipped with an ESI source and deuterium oxide (D2O) as the sheath liquid allows H/D exchange experiments to be performed on-line. This directly provides information for determining the number and position of exchangeable hydrogens, aiding in the elucidation of the structures of drug metabolites. To demonstrate the utility of this method, LC-mass spectrometry (MS) and LC-MS/MS experiments were performed using either H2O or D2O as sheath liquid on a matrix metalloprotease (MMP) inhibitor (PD 0200126) and its metabolites. Examination of the mass shift of the deuteriated molecule from that of the protonated molecule allowed the number of exchangeable protons to be determined. Interpretation of the production-spectra helped to determine the location of the exchanged protons and assisted in the assignment of the site(s) of modification for each metabolite.

High indinavir Cmin is associated with higher toxicity in patients on indinavir-ritonavir 800/100 mg twice-daily regimen

We retrospectively evaluated the incidence of side effects and treatment intervention according to indinavir trough concentration in 63 patients taking indinavir-ritonavir 800/100 mg twice daily. Median indinavir trough concentration was 1446 ng/mL at 800/100 mg twice daily associated with 60% of measured toxicity. Among patients with indinavir trough concentration >500 ng/mL, 46 of 49 had a dosage adjustment and 17 have had more than two dosage adjustments. The primary reason for dosage adjustment was toxicity in 69% (43 cases). Renal and cutaneous toxicity were predominant.After dosage adjustment, median indinavir trough concentration was 459 ng/mL, which was associated with 8% of toxicity. Trough concentrations >500 ng/mL were correlated with increased toxicity (p <.05) and more treatment intervention (p =.02). In conclusion, achievement of indinavir trough concentrations <500 ng/mL appears to be safe, and an optimal concentration range for indinavir trough concentration could be 150 to 500 ng/mL for an indinavir-ritonavir twice daily regimen.

Acute pancreatitis in Soweto, South Africa: relationship between trypsinogen load, trypsinogen activation, and fibrinolysis

OBJECTIVE

It is not known why acute pancreatitis in Soweto, South Africa, pursues an aggressive course. We sought clues from circulating trypsinogen load at admission as marker of initial acinar injury, trypsinogen activation using the carboxypeptidase B activation peptide as surrogate, proteinase inhibitors, the coagulation-fibrinolysis axis, indicators of inflammation, oxidative stress markers, and antioxidant status. This article reports on the first four aspects.

METHODS

The study involved 24 consecutive patients with a first attack. All of them were admitted within 24 h, and 22 were alcoholic. Urine was analyzed for anionic trypsinogen and the carboxypeptidase B activation peptide. Serum was tested for anionic and cationic trypsinogen, alpha1 proteinase inhibitor and alpha2 macroglobulin. Plasma from a subset was assayed for soluble fibrin, cross-linked fibrin degradation products (surrogates for thrombin and plasmin activity, respectively), and tissue-type plasminogen activator and inhibitor.

RESULTS

Soweto controls had higher serum anionic trypsinogen (p = 0.004) and plasminogen activator:inhibitor ratio (p = 0.047) than U.K. controls. The outcome of acute pancreatitis was mild in 17 but severe in seven with three deaths, two on day 2. In mild pancreatitis, intense plasmin activity (p < 0.001) accompanied the surge in trypsinogen, especially anionic (p < 0.001), but without increased thrombin activity and in five patients without trypsinogen activation. In severe pancreatitis, further significant increments in plasmin activity and trypsinogens were accompanied by increased thrombin activity (p = 0.013) and trypsinogen activation (p = 0.046). There was no correlation between surrogates of plasmin and thrombin activity, or between either and the carboxypeptidase B activation peptide, which showed a curvilinear relationship to total serum trypsinogen.

CONCLUSIONS

The aggressive nature of alcoholic acute pancreatitis in Soweto seems to reflect early profound fibrinolysis, which precedes coagulation and is initially independent of trypsin. Subclinical acinar-cell injury and a profibrinolytic diathesis in outwardly healthy Sowetans may predispose to this problem.

The influence of green tea on the activity of proteases and their inhibitors in plasma of rats after ethanol treatment

Ethanol oxidation in the liver is accompanied by formation of acetaldehyde and free radicals. These compounds can react with biologically active proteins, including proteolytic enzymes and their inhibitors. The aim of this paper was to determine the influence of green tea on the activity of cathepsin G and elastase and their inhibitors such as alpha-1-antitrypsin and alpha-2-macroglobulin, total antioxidant status and lipid peroxidation in plasma of young rats chronically intoxication with ethanol. The activity of cathepsin G and elastase was increased, while the activity of their inhibitors was reduced after ethanol treatment. AT the same time, the total antioxidant status was significantly decreased while lipid peroxidation measured as malondialdehyde and 4-hydroxynonenal was significantly increased. Giving green tea to rats did not change the proteases and their inhibitors activity, but significantly increased total antioxidant status and decreased lipid peroxidation. Drinking green tea with ethanol partially prevents the changes observed after ethanol intoxication.

New strategy for antedrug application: development of metalloproteinase inhibitors as antipsoriatic drugs

Phosphonamide-based inhibitors were synthesized and evaluated for the inhibitory activities against the shedding of epidermal growth factors, amphiregulin and heparin-binding EGF-like growth factor, that would participate in the development of psoriasis. All compounds exhibited excellent inhibitory activities for these EGF sheddings; however, they also inhibited matrix metalloproteinases (MMPs). To avoid adverse effects reported by the clinical development of MMP inhibitors, the antedrug concept was introduced. Among the phosphonamide inhibitors, the 2,2,2-trifluoroethyl ester 8d and 2,2-difluoroethyl ester 8c showed rapid decomposition in human plasma, which is an essential property for the antedrug. Topical applications of these compounds significantly suppressed TPA-induced epidermal hyperplasia in murin skin, a model of psoriasis. These results suggested that the phosphonamide-based inhibitors have a therapeutic potential for the treatment of psoriasis as an antedrug application.

Gene therapy of melanoma pulmonary metastasis by intramuscular injection of plasmid DNA encoding tissue inhibitor of metalloproteinases-1

Tumor cell invasion and metastasis are a complex multistep process that involves the degradation of extracellular matrix proteins by matrix metalloproteinases. Tissue inhibitor of metalloproteinase-1 (TIMP-1) acts as a negative regulator of matrix metalloproteinases and thus prevents tumor cell invasion and metastasis by preserving extracellular matrix integrity. In the present study, we investigated whether increasing serum TIMP-1 levels by gene transfer would decrease experimental pulmonary metastasis of melanoma in C57BL/6 mice. Female animals bearing B16F10 melanoma pulmonary metastasis were injected intramuscularly twice per week with 100 microg of plasmid DNA encoding the human TIMP-1 cDNA (TIMP-1pDNA). Substantive levels of serum human TIMP-1 were observed 3 days after single injection and were found for 6 days thereafter. Pulmonary metastasis was significantly reduced in the mice following 4 weeks of TIMP-1 treatment as compared to the controls that were treated with the plasmid DNA vector alone. Further reduction of pulmonary metastasis and increase in survival were realized by intraperitoneal injection of 1000 U of IL-2 twice per week in combination with TIMP-1 treatment. In a parallel in vitro study, a 3-fold increase in TIMP-1 expression was observed in NIH3T3 cells after IL-2 treatment. Therefore, up-regulation of TIMP-1 expression by IL-2 likely contributed to the additive effect of IL-2 and TIMP-1 in reducing metastatic disease in the animal model. In conclusion, our findings support the potential of TIMP-1 gene therapy for the prevention of metastatic melanoma.

Plasma drug levels, genotypic resistance, and virological response to a nelfinavir plus saquinavir-containing regimen

OBJECTIVE

To determine the importance of resistance and drug levels in the response to a dual-protease inhibitor (PI) combination.

METHODS

Prospective study of 62 HIV-positive patients who switched to a salvage regimen including nelfinavir plus saquinavir. Virological response was defined as a decrease in viraemia > 0.5 log10 after 24 weeks. Optimal PI levels were defined as those above the protein binding-corrected 95% inhibitory concentration (IC95), as estimated in the presence of 50% human serum.

RESULTS

Baseline median HIV load was 4.78 log10 copies/ml. The median number of mutations in the protease gene was nine (range, 2-25), predominantly at residues 82 (52%), and 90 (40%). After 24 weeks, 45% of patients had responded and 19% were < 50 copies/ml. A higher number of mutations in the protease gene (12 versus 8;P = 0.001), and the L90M mutation (36% versus 67%; P = 0.001) were associated with treatment failure. Trough levels of nelfinavir and saquinavir were two- and fivefold, respectively, greater than those reached when used as the only PI (2480 and 260 ng/ml, respectively), and they were above the estimated protein-corrected IC95 in 96% and 32% of cases. Thus, the Cmin : IC95 ratio ranged from 0.1 to 10 for nelfinavir and from 0.12 to 3.24 for saquinavir. Suboptimal PI levels were associated with a poorer response, but there was no correlation between optimal drug levels and a better response.

CONCLUSION

Genotypic resistance predicts the virological response to a nelfinavir-saquinavir salvage regimen. Our data suggest that higher than optimal drug levels could be necessary to control the replication of many PI-resistant viruses.

Changes in plasma antiproteases in paraquat poisoned rats using micro two-dimensional electrophoretic analysis

Rats were subjected to subacute paraquat (PQ) exposure (7 mg/kg sc daily for 6-9 administrations). They were divided into a group that died from subacute toxicity, a group that recovered from the subacute toxicity and progressed to pulmonary fibrosis, and a group that showed no effects from the PQ. The rats with subacute fatal toxicity had a remarkable increase in a2M-1. Those which progressed to pulmonary fibrosis had remarkable decreases in a2M-2, a2M-3, and a2M-4 and a1AT. The rats that showed no effects from the PQ had relative increases in all molecular species of a2M. Increases in major a2M molecular species, a2M-1 and a2M-4, and a minor molecular species, a2M-3, were characteristically observed.

Affinity chromatography in the industrial purification of plasma proteins for therapeutic use

Affinity chromatography is a powerful technique for the purification of many proteins in human plasma. Applications cover the isolation of proteins for research purposes but also, to a large extent, for the production of therapeutic products. In industrial plasma fractionation, affinity chromatography has been found to be particularly advantageous for fine and rapid capture of plasma proteins from industrial plasma fractions pre-purified by ethanol fractionation or by ion-exchange chromatography. To date, affinity chromatography is being used in the production of various licensed therapeutic plasma products, such as the concentrates of Factor VIII, Factor IX, von Willebrand Factor, Protein C, Antithrombin III, and Factor XI. Most commonly used ligands are heparin, gelatin, murine antibodies, and, to a lesser extent, Cu(2+). Possible development of the use of affinity chromatography in industrial plasma fractionation should be associated to the current development of phage display and combinatorial chemistry. Both approaches may lead to the development of tailor-made synthetic ligands that would allow implementation of protein capture technology, providing improved productivity and yield for plasma products.