Search PubMed⌕ Search

Biomedical subjects

M Villain

Publications and source records attributed to M Villain.

At least 19 recordsLinked to original sources
PubMed2006

[The French glaucoma and ocular hypertension 1-day study].

PURPOSE: The purpose of this study was to describe the distribution and characteristics (age, duration, type, treatment, etc.) of ocular hypertension and glaucoma in French ophthalmologic practices. METHODS: The French glaucoma and ocular hypertension 1-day study is a descriptive cross-sectional "1-day" type survey, conducted among all ophthalmologists of mainland France. They had to include all patients aged 18 years and over with ocular hypertension or glaucoma who were seen on November 25th 2003. The participation rate was 24.0% (1.173 ophthalmologists). Among the 3.919 patients included, 3.896 subjects (99%) had usable data for the statistical analyses. RESULTS: The ophthalmologists reported treating 16 patients with ocular hypertension or glaucoma on average per week. Among the patients, 29.5% had ocular hypertension, 61.7% had open-angle glaucoma, 3.4% had normal tension glaucoma, and 5.5% angle-closure glaucoma. The ophthalmologists used surgery or laser treatment for 74.1% of angle-closure glaucoma, while for other pathologies, treatment with drugs only was preponderant. More than 87% of patients received one or several ocular treatments: beta-blockers (59.3%), prostaglandins (50.1%), carbonic anhydrase inhibitors (21.6%), or mydriatic sympathomimetics (6.3%). CONCLUSIONS: The characteristics of glaucoma and ocular hypertension (type of glaucoma, age, duration, etc.) correspond to those of other Western populations. The therapeutic habits of French ophthalmologists is in line with current international guidelines.

Aged↗
PubMed2005

Evidence of addiction by anesthesiologists as documented by hair analysis.

Chemical dependency is a disease that can affect all professions. Among the health care professionals, anesthesiologists represent a specific group. Numerous factors have been proposed to explain the high incidence of drug abuse among anesthesiologists. These include: easy access to potent drugs, particularly narcotics, highly addictive potential of agents with which they are in contact, and easy diversion of these agents since only small doses will initially provide an effect desired by the abuser. Opioids are the drugs of choice for anesthesiologists, and among them fentanyl and sufentanil are the most commonly used. Alcohol is mostly abused by older anesthesiologists. Propofol, ketamine, thiopental and midazolam are also abused. In fact, all but quaternary ammonium drugs can be observed. Signs and symptoms of addiction in the hospital workplace include: unusual changes in behavior, desire to work alone, refusal of lunch relief or breaks, volunteer for extra cases, call, come in early and leave late, frequent restroom breaks, weight loss and pale skin, malpractice, behind on charts .... Toxicological investigations are difficult, as the drugs of interest are difficult to test for. In most cases, half-lives of the compounds are short, and the circulating concentrations weak. It is, therefore, necessary to develop tandem mass spectrometry procedures to satisfy the criteria of identification and quantitation. In most cases, blood and/or urine analyses are not useful to document impairment, as these specimens are collected at inadequate moments. Hair analysis appears, therefore, as the unique choice to evidence chronic exposure. Depending the length of the hair shaft, it is possible to establish an historical record, associated to the pattern of drug use, considering a growth rate of about 1cm/month. An original procedure was developed to test for fentanyl derivatives. After decontamination with methylene chloride, drugs are extracted from the hair by liquid/liquid extraction after incubation in pH 8.4 phosphate buffer. Fentanyl derivatives are analyzed by GC-MS/MS. The following cases are included in this paper: Case 1: 50-year-old anesthetist, positive for fentanyl (644 pg/mg); Case 2: 42-year-old anesthetist, positive for fentanyl (101 pg/mg) and sufentanil (2 pg/mg); Case 3: 40-year-old anesthetist, positive for codeine (210 pg/mg), alfentanil (30 pg/mg) and midazolam (160 pg/mg); Case 4: 46-year-old nurse, found dead, positive for alfentanil (2 pg/mg) and fentanyl (8 pg/mg). In these cases, the combination of an alternative specimen (hair) and hyphenated analytical techniques (tandem mass spectrometry) appears to be a pre-requisite.

Adult↗
PubMed2005

Dioxins and furans determination in postmortem blood by gas chromatography--high-resolution mass spectrometry.

Dioxins and related compounds (furans) are persistent environmental contaminants that cause adverse biological effects. Their influence on humans is still unclear, except for accidental high-dose exposure. However, chronic exposure to these compounds seems to be involved in cancer, endocrine disruption, and neurobehavioral effects. For several years, a large concern about the potential health risks of dioxins is emerging in Europe and United States. Dioxin levels in biological specimens are extremely low and require very sensitive and specific methods of analysis. In this study, gas chromatography coupled to high-resolution mass spectrometry was used to evaluate dioxin body burden of two women deceased from generalized cancer. Fat fraction of blood specimens was obtained after precipitation with ethanol and extraction of both liquid and solid phases spiked with labeled 13C12-dioxin analogues. Organic phases were grouped, washed, and evaporated to weigh the lipid content. Lipids were dissolved in hexane, hydrolyzed with concentrated sulfuric acid, and discarded during water washes. Dioxins purification was achieved using three successive columns: silica, alumina/sodium sulfate, and carbon/Celite. Finally, the toluene eluent was evaporated and the extract injected in the analytical system. After chromatographic separation, detection was achieved in single ion monitoring mode using a high-resolution mass spectrometer operating in electron impact ionization mode (40 eV, minimal resolution of 10,000). Dioxin levels were expressed in pg TEQ/g of fat as defined by the World Health Organization. Quantification limits for each dioxin congener ranged from 2.5 to 12.0 pg/g fat with a relative extraction recovery always higher than 60%. Dioxin concentrations in the blood of the two deceased women were 35.0 and 42.7 pg TEQ/g fat, respectively. These concentrations are largely lower than those observed after accidental releases, but in the range of those observed in the general European population. Therefore, it was not possible to correlate dioxin body burden of the two women as a potential contributor of their cancer pathology. Nevertheless, knowledge of dioxin body burden in the French population would be of interest for an accurate interpretation of these results.

Aged↗
PubMed2004

Identification of alprazolam in hair in two cases of drug-facilitated incidents.

The use of a drug to modify a person's behaviour for criminal gain is not a recent phenomenon. However, the recent increase in reports of drug-facilitated crimes (sexual assault, robbery) has caused alarm by the general public. Among the drugs that can be used, alprazolam (Xanax), an anxiolytic benzodiazepine, has been seldom observed. To document two cases involving this drug, we have developed an approach based on hair testing by LC-MS/MS. After pH 8.4 buffer incubation and extraction with methylene chloride/diethyl ether (80/20, v/v), hair extracts were separated on a XTerra MS C18 column using a gradient of acetonitrile and formate buffer. Alprazolam and diazepam-d5, used as internal standard, were detected by electrospray tandem mass spectrometry. In the first criminal case, alprazolam tested positive in two consecutive 2 cm hair segments at 4.9 and 2.4 pg/mg, from a 12-year-old girl, assaulted by her father who had sedated her three or four times. In the other case, alprazolam was detected in four consecutive 1cm hair segments at 3.1-0.4 pg/mg, obtained from an adolescent who had been forced to prostitute herself.

Adolescent↗
PubMed2004

Testing for zopiclone in hair application to drug-facilitated crimes.

The use of a drug to modify a person's behaviour for criminal gain is not a recent phenomenon. However, the recent increase in reports of drug-facilitated crimes (sexual assault, robbery) has caused alarm in the general public. The drugs involved can be difficult to detect due to low dosages or chemical instability. They possess amnesic properties and can be quickly cleared from the body fluids. In these situations, blood or even urine can be of poor interest. This is the reason why this laboratory developed an original approach based on hair testing by LC-MS/MS. Zopiclone (Imovane), due to its short half-life associated with rapid hypnotic activity, is considered as a compound of choice to sedate victims. To document the detection of zopiclone in hair, we first tested specimens obtained from two volunteers who had ingested a single 7.5 mg Imovane tablet, and from repetitive consumers of zopiclone. After pH 8.4 buffer incubation and extraction with methylene chloride/diethyl ether (80/20 (v/v)), hair extracts were separated on a Xterra MS C18 column using a gradient of acetonitrile and formate buffer. Zopiclone and diazepam-d5, used as internal standard, were detected by tandem mass spectrometry. A single exposure to zopiclone was detectable in the first hair segment of two volunteers at concentration of 5.4 and 9.0 pg/mg, respectively. Hair from repetitive consumers tested positive for zopiclone at concentrations of 37 and 66 pg/mg. Hair analysis was applied to two authentic criminal cases. In the first one, zopiclone tested positive in the corresponding hair segment at 4.2 pg/mg, in accordance with a single exposure to the drug. In the other expertise, zopiclone was detected in the two segments analyzed, at 21.3 and 21.5 pg/mg, making unlikely the hypothetical single exposure to zopiclone.

Adolescent↗
PubMed2004

Evaluation of the One-Step ELISA kit for the detection of buprenorphine in urine, blood, and hair specimens.

A solid-phase enzyme immunoassay involving microtiter plates was recently proposed by International Diagnostic Systems corporation (IDS) to screen for buprenorphine in human serum. The performance of the kit led us to investigate its applicability in other biological matrices such as urine or blood, and also hair specimens. Low concentrations of buprenorphine were detected with the ELISA test and confirmed by HPLC/MS (buprenorphine concentrations measured by HPLC/MS: 0.3 ng/mL in urine, 0.2 ng/mL in blood, and 40 pg/mg in hair). The intra-assay precision values were 8.7% at 1 ng/mL of urine (n = 8), 11.5% at 2 ng/mL in serum (n = 8), and 11.5% at 250 pg/mg of hair (n = 8), respectively. The immunoassay had no cross-reactivity with dihydrocodeine, ethylmorphine, 6-monoacetylmorphine, pholcodine, propoxyphene, dextromoramide, dextrometorphan at 1 and 10 mg/L, or codeine, morphine, methadone, and its metabolite EDDP. A 1% cross-reactivity was measured for a norbuprenorphine concentration of 50 ng/mL. Finally, the immunoassay was validated by comparing authentic specimens results with those of a validated HPLC/MS method. From the 136 urine samples tested, 93 were positive (68.4%) after the ELISA screening test (cutoff: 0.5 ng/mL) and confirmed by HPLC/MS (buprenorphine concentrations: 0.3-2036 ng/mL). From the 108 blood or serum samples screened, 27 were positive (25%) after the ELISA test with a cutoff value of 0.5 ng/mL (buprenorphine concentrations: 0.2-13.3 ng/mL). Eighteen hair specimens were positive (72%) after the screening (cutoff: 10 pg/mg) and confirmed by LC/MS (buprenorphine concentrations: 40-360 pg/mg). The ELISA method produced false positive results in less than 21% of the cases, but no false negative results were observed with the immunological test. Four potential adulterants (hypochloride 50 mL/L, sodium nitrite 50 g/L, liquid soap 50 mL/L, and sodium chloride 50 g/L) that were added to 10 positive urine specimens (buprenorphine concentrations in the range 5.3-15.6 ng/mL), did not cause a false negative response by the immunoassay.

Buprenorphine↗
PubMed2004

Windows of detection of zolpidem in urine and hair: application to two drug facilitated sexual assaults.

A LC-MS/MS method for the detection of zolpidem in hair was developed to detect this drug after a single dose in possible drug facilitated sexual assaults. To determine the window of detection of zolpidem in both urine and hair, three volunteers received a 10 mg dose. Urine specimens were collected each 12 h for 144 h. Hair was sampled 3-5 weeks after exposure. Hair and urine extracts were separated on a Xterra MS C18 column using a gradient of acetonitrile and formate buffer. For each compound, detection was related to two daughter ions. Zolpidem was detected for up to 60 h in urine with peak concentrations obtained at 12 h. A single exposure to zolpidem was detected in hair at concentrations ranging from 1.8 to 9.8 pg/mg. Hair analysis was applied to two possible criminal cases. In the first case, zolpidem tested positive in the corresponding hair segment at 4.4 pg/mg. In the other case, zolpidem was detected in all the segments analyzed, demonstrating likely previous drug use in addition to recent exposure associated with a positive blood result.

Adult↗
PubMed2003

Testing for kavain in human hair using gas chromatography-tandem mass spectrometry.

A sensitive, specific and reproducible method for the quantitative determination of kavain in human hair has been developed. The sample preparation involved a decontamination step of the hair with methylene chloride. The hair sample (about 50 mg) was incubated in 1 ml of methanol for 1 h, in an ultrasonic bath, in presence of 20 ng of methaqualone-d7 used as internal standard. The methanolic solution was evaporated to dryness, and the residue reconstituted by adding 30 microl of methanol. A 2 microl aliquot of the extract was injected onto the column (Optima5-MS capillary column, 5% phenyl-95% methylsiloxane, 30 m x 0.25 mm i.d. x 0.25 mm film thickness) of a Hewlett-Packard (Palo Alto, CA) gas chromatograph (5890). Kavain was detected by its parent ion at m/z 230 and daughter ions at m/z 111 and 202 through a Finnigan TSQ 700 MS/MS system. The assay was capable of detecting 30 pg/mg of kavain (limit of detection (LOD)). Linearity was observed for kavain concentrations ranging from 100 to 2000 pg/mg with a correlation coefficient of 0.998. Intra-day precision at 400 pg/mg was 13.7%. The analysis of a segment of hair, obtained from an occasional consumer, revealed the presence of kavain at the concentration of 418 pg/mg. A higher concentration (1708 pg/mg) was detected in the corresponding pubic hair.

Calibration↗
PubMed2003

Screening procedure for eight quaternary nitrogen muscle relaxants in blood by high-performance liquid chromatography-electrospray ionization mass spectrometry.

A screening procedure was developed for the identification and the quantification of eight quaternary nitrogen muscle relaxants, including d-tubocurarine, alcuronium, pancuronium, vecuronium, atracurium, mivacurium, rocuronium and mebezonium, in blood samples. The procedure involves ion-pair extraction with methylene chloride at pH 5.4, reversed-phase HPLC separation and electrospray ionization mass spectrometry detection. The procedure was validated in terms of linearity (0.929 5 for all the target compounds at 0.1 mg/l). The screening test was found satisfactory and applied in two fatal deaths. In the first case, toxicological investigations on biological fluids collected during the autopsy revealed the presence of vecuronium (1.2 and 0.6 mg/l in blood and urine, respectively) and its desacetylated metabolite, 3-hydroxy-vecuronium (4.4 and 0.7 mg vecuronium equivalent/l in blood and urine, respectively). In the second forensic case, blood analysis showed high levels of mebezonium (6.5 mg/l). The developed procedure was found suitable for forensic investigations.

Adult↗
PubMed2003

HPLC/MS findings in a fatality involving sustained-release verapamil.

A fatality involving verapamil, a calcium channel blocker agent, is presented. A 51-year old male ingested 7200 mg of sustained-release (SR) verapamil at T0 and died 40 hours later of refractory, mixed shock and multiorgan failure. The symptoms displayed during hospitalization were quite typical and involved altered consciousness, hypotension, bradycardia, atrioventricular block, metabolic acidosis and renal failure. Verapamil and its primary metabolite, norverapamil, were assayed on eight plasma and two urine samples, successively taken between the admission to the ICU (T0 + 4 hours) and time of death, using an original high-performance liquid chromatography/mass spectrometry (HPLC/MS) procedure with verapamil-d3 as internal standard. Plasma verapamil and norverapamil levels on admission were 0.94 and 1.36 microg/mL, respectively, then verapamil remained practically unchanged throughout the hospitalization (0.85 microg/mL at T0 + 40 hours). The discussion focuses on the detrimental role of SR formulations in overdose, with special emphasis on the risk of pharma-cobezoar development already reported with SR-verapamil. To our knowledge, this is the first report of a verapamil fatality documented by repeated plasma measurements of the drug during the antemortem period.

Calcium Channel Blockers↗
PubMed2002

Doping control for methenolone using hair analysis by gas chromatography-tandem mass spectrometry.

A sensitive, specific and reproducible method for the quantitative determination of methenolone in human hair has been developed. The sample preparation involved a decontamination step of the hair with methylene chloride. The hair sample (about 100 mg) was solubilized in 1 ml 1 M NaOH, 15 min at 95 degrees C, in presence of 1 ng testosterone-d3 used as internal standard. The homogenate was neutralized and extracted using consecutively a solid-phase (Isolute C18 eluted with methanol) and a liquid-liquid (pentane) extraction. The residue was derivatized by adding 50 microl MSTFA-NH4I-2-mercaptoethanol (1000:2:5, v/v/v), then incubated for 20 ml at 60 degrees C. A 1.5-microl aliquot of the derivatized extract was injected into the column (HP5-MS capillary column, 5% phenyl-95% methylsiloxane, 30 m x 0.25 mm I.D., 0.25 microm film thickness) of a Hewlett-Packard (Palo Alto, CA, USA) gas chromatograph (6890 Series). Methenolone was detected by its parent ion at m/z 446 and daughter ions at m/z 208 and 195 through a Finnigan TSQ 700 MS-MS system. The assay was capable of detecting 1 pg/mg of methenolone when approximately 100 mg hair material was processed. Linearity was observed for methenolone concentrations ranging from 2 to 100 pg/mg with a correlation coefficients of 0.965-0.981. Intra-day and between-day precisions at 2, 10 and 25 pg/mg were 10.9-14.1% and 13.7-16.8%, respectively, with an extraction recovery of 97.6%. The analysis of a strand of hair obtained from two bodybuilders, revealed the presence of methenolone at the concentrations of 7.3 and 8.8 pg/mg.

Anabolic Agents↗
PubMed2002

[Crime under the influence of psychoactive drugs: the problem of the duration of detection].

On a regular basis, the media presents the potential risks of the use of psycho-active compounds, including misused pharmaceuticals (flunitrazepam, GHB) or drugs of abuse (cannabis, LSD, ecstasy). Ethanol is also frequently encountered. These drugs can be used for recreational purposes by addicts or can be observed after sexual assaults (drugs spiked in food). Forensic toxicology can be involved in several situations to document impairment, such as: crime under influence, date rape, driving under influence, psychiatric disorders, determination of the cause of death... In some particular situations, it can be very cautious to investigate exposure to psycho-active drugs, due to late sampling of biological specimens. To enhance the window of detection of 3 specific drugs, the authors propose the following: 1. Use of an ultra-sensitive technique, such as GC/MS/MS/NCI for 7-aminoflunitrazepam; 2. Use of a cumulative specimen, such as sweat for GHB and 3. Use of a metabolite with a long half-life, such as ethyl glucuronide for ethanol.

Cause of Death↗
PubMed2001

Prevention and reversal of experimental autoimmune myasthenia gravis by a monoclonal antibody against acetylcholine receptor-specific T cells.

We have recently described an algorithm to design, among others, peptides with complementarity contour to autoimmune epitopes. Immunization with one such peptide resulted in a monoclonal antibody (mAb), termed CTCR8, that specifically recognized Vbeta15 containing TCR on acetylcholine receptor (AChR) alpha-chain residue 100-116-specific T cells. CTCR8 was found to label the cell surface of AChR100-116-specific T cell lines and clones, immunoprecipitate the TCR from such cells, and block their proliferative responses to AChRalpha100-116. In the present report, we have found that there is a marked reduction in IFN-gamma and no effect on IL-10 production in a CTCR8-treated AChRalpha100-116-specific T cell line. Interestingly, when AChR100-116-primed, primary T cells were stimulated with peptide and treated with CTCR8, there was once again inhibition of IFN-gamma but also marked stimulation of IL-10 production. The change in the Th1/Th2 cytokine profile was paralleled by a reduction in AChR-specific IgG2a and IgM with no effect on IgG1. Remarkably, the most profoundly inhibited Ab population was that which causes experimental autoimmune myasthenia gravis (EAMG) by reaction with the main immunogenic region (alpha61-76) of the AChR. Based on these results, CTCR8 was tested for prophylactic and therapeutic effects in EAMG. EAMG induced by immunization with purified native Torpedo AChR was both inhibited and reversed by CTCR8. These findings suggest a means to produce therapeutic mAb for the treatment of autoimmune diseases.

Animals↗
PubMed2001

Attenuation of very late antigen-5-mediated adhesion of bone marrow-derived mast cells to fibronectin by peptides with inverted hydropathy to EF-hands.

Release of allergic mediators from mast cells is enhanced by very late Ag (VLA)-5-mediated interaction of these cells with fibronectin. In this report, we show that VLA-5-mediated adhesion of bone marrow-derived mast cells to fibronectin can be induced by two different pathways: first, FcepsilonRI clustering, which depends on calmodulin activation and extracellular Ca(2+), and, second, by Mn(2+) stimulation, which is independent of calmodulin activation and antagonized by Ca(2+). Previous studies have shown the presence of several cation-binding domains in VLA-5 that are homologous to the calcium-binding EF-hands of calmodulin. To show a role for EF-hands of different proteins in VLA-5-mediated adhesion, we used calcium-like peptides (CALP), CALP1 and CALP2, designed to bind to EF-hands based on inverted hydropathy. CALP1 and, more potently, CALP2 inhibited FcepsilonRI-induced adhesion to fibronectin via different mechanisms. The target for the effects of CALP1 and 2 on FcepsilonRI-induced adhesion and degranulation was intracellular and likely involved calmodulin. Interestingly only CALP2 was able to inhibit Mn(2+)-induced calmodulin-independent adhesion by interfering with an extracellular target, which is probably VLA-5. We conclude that CALP1 and 2 can inhibit VLA-5-mediated adhesion of mast cells to fibronectin through binding to EF-hands of multiple proteins, and that these peptides can be used as lead compounds for the development of future therapy against allergy.

Adjuvants, Immunologic↗
PubMed2001

Covalent capture: a new tool for the purification of synthetic and recombinant polypeptides.

BACKGROUND: Purification of polypeptides and proteins derived from recombinant DNA techniques and of long synthetic polypeptides often represents a challenge. Affinity methods exist, but generally require addition of a large recognition unit to the target protein and use of expensive purification media. Use of large units is dictated by the characteristics of non-covalent complexes, where the energy necessary to form the complex derives from the sum of multiple weak energy interactions. Covalent interactions in contrast are of high energy, even when only a few bonds are formed. We decided to explore the use of the reversible covalent bond formed between N-terminal cysteine and threonine residues with an aldehyde as a method of protein purification. RESULTS: A series of test peptides with N-terminal cysteine and threonine were captured by a polyethyleneglycol-polyacrylamide resin to which an aldehyde function had been grafted. Peptides with other amino acids at the N-terminus did not interact with the resin. A recombinant polypeptide with N-terminal cysteine was purified to 90% purity in one step. Polypeptides were eluted from the resin simply by adding a hydroxylamine derivative, which reacts with aldehyde functions to form an oxime. CONCLUSIONS: Polypeptides possessing N-terminal cysteine or threonine can be easily purified using this 'covalent capture' approach.

Aldehydes↗
PubMed2001

The role of adjuvants in the efficacy of a peptide vaccine for myasthenia gravis.

Myasthenia gravis (MG) and its animal model, experimental autoimmune (EA) MG, are caused by interference with neuromuscular transmission by autoantibodies against the nicotinic acetylcholine receptor (AChR) on muscle. Previously, we have shown that two peptides, denoted RhCA 67-16 and RhCA 611-001, designed to be complementary in structure to the main immunogenic region and the dominant Lewis rat T cell epitope (alpha-chain residues 100-116) of the AChR, respectively, are effective vaccines that prevent EAMG in rats by inducing antiidiotypic/clonotypic antibodies (Ab) and lowering levels of AChR Ab. These studies employed keyhole limpet hemocyanin (KLH) as a carrier and complete Freunds adjuvant (CFA). In advance of a clinical trial the present study tested the efficacy of RhCA 611-001 when combined with different adjuvants that are approved for use in humans. Adjuvants chosen for comparison were incomplete Freunds adjuvant (IFA) and aluminum hydroxide (Alum). As a second goal we evaluated diphtheria toxin (DT) as an alternative carrier protein to KLH. Alum was found to be an effective adjuvant, particularly when used with the peptide conjugated to DT. This combination of carrier and adjuvant provided protection against EAMG comparable with that observed with CFA and KLH. Using enzyme-linked immunosorbent assays for Ab against RhCA 611-001, it was found that disease protection is qualitatively, but not quantitatively, related to the anti-peptide Ab response. Our results demonstrate a vaccine formulation that should be useful in the first soon-to-be-conducted clinical trials of peptide vaccines to specifically correct aberrant T and B cell responses in an autoimmune disease.

Adjuvants, Immunologic↗
PubMed2001

Inhibitory effect of a complementary peptide on ulceration in the alkali-injured rabbit cornea.

PURPOSE: Two tripeptide chemoattractants, acetyl-proline-glycine-proline (Ac-PGP) and methyl-proline-glycine-proline (Me-PGP), are the primary triggers for early neutrophil invasion into the alkali-injured cornea. In the present study the effectiveness of a complementary peptide designed to inhibit the PGP chemoattractants (arginine-threonine-arginine [RTR] tetrameric peptide) and an apo A-1 mimicking peptide (5F) was investigated in the alkali-injured rabbit eye. METHODS: (L)-RTR tetramer, (D)-RTR tetramer, and 5F were tested in vitro for their effects on neutrophil polarization. Synthetic 5F was also tested in vitro for its effect on the neutrophil respiratory burst. In the alkali-injured rabbit eye model, the right corneas of 48 rabbits were exposed to 1 N NaOH for 35 seconds. Sixteen animals were randomly assigned to each of three groups: phosphate-buffered saline (PBS) control; 800 microM RTR (dextrorotatory) tetramer in PBS alternating each hour with 1.5 mM RTR (levorotatory) tetramer in PBS; and 12 microM 5F in PBS. One topical drop of each substance was administered hourly (14 times per day) for 33 days. The experiment was continued until day 42 with no additional drops administered. RESULTS: (L)-RTR tetramer and (D)-RTR tetramer inhibited neutrophil polarization activated by the PGP chemoattractants in vitro. Synthetic 5F did not inhibit neutrophil polarization in the presence of Ac-PGP or the respiratory burst of neutrophils in the presence of a metabolic stimulant derived from alkali-degraded corneas. During the entire animal experiment, statistically fewer ulcers occurred in the RTR tetramer group than in the PBS control group (43.8% vs. 87.5%, P = 0.0046). The frequency of ulceration in the 5F group (68.8%) was not significantly different from the PBS control group. CONCLUSIONS: The reduction in the frequency of corneal ulceration by the RTR tetramer possibly resulted from its complementary binding to Ac-PGP and Me-PGP in the cornea shortly after alkali injury, leading to a reduction in the early and late infiltration of neutrophils. RTR tetramer appears to hold enough promise to warrant additional study as a therapeutic drug for the alkali-injured eye.

Animals↗