Molecular typing of methicillin-resistant Staphylococcus aureus by pulsed-field gel electrophoresis: comparison of results obtained in a multilaboratory effort using identical protocols and MRSA strains

Pulsed-field gel electrophoresis (PFGE) has become the gold standard of molecular methods in epidemiological investigations. In spite of its high resolving power, use of the method has been hampered by inadequate laboratory-to-laboratory reproducibility. In the project described here we have addressed this problem by organizing a multilaboratory effort in which the same bacterial strains (subtype variants of the Iberian and Brazilian methicillin-resistant Staphylococcus aureus--MRSA--clones) were analyzed by twenty investigators in thirteen different laboratories according to an indentical protocol, which is reproduced here in detail. PFGE patterns obtained were analyzed at a central laboratory in order to identify specific technical problems that produced substandard macrorestriction patterns. The results including the specific technical problems and their most likely causes are described in this communication. Also listed are seven major epidemic clones of MRSA which have been characterized by molecular fingerprinting techniques and the prototypes of which have been deposited at the American Type Culture Collection, from where they will be available for interested investigators for the purpose of typing MRSA isolates. It is hoped that this communication will contribute to the improvement of the reproducibility and technical/aesthetic quality of PFGE analysis.

Ventricular tachycardias arising from the aortic sinus of valsalva: an under-recognized variant of left outflow tract ventricular tachycardia

OBJECTIVES

To describe a normal heart left bundle branch block, inferior axis ventricular tachycardia (VT), that could not be ablated from the right or left ventricular outflow tracts.

BACKGROUND

Whether these VTs are epicardial and can be identified by a specific electrocardiographic pattern is unclear.

METHODS

Twelve patients with normal heart left bundle branch block, inferior axis VT and previously failed ablation were included in this study. Together with mapping in the right and left ventricular outflow tracts, we obtained percutaneous epicardial mapping in the first five patients and performed aortic sinus of Valsalva mapping in all patients.

RESULTS

No adequate pace mapping was observed in the right and left ventricular outflow tracts. Earliest ventricular activation was noted in the epicardium and the aortic cusps. All patients were successfully ablated from the aortic sinuses of Valsalva (95% CI 0% to 18%). The electrocardiographic pattern associated with this VT was left bundle branch block, inferior axis and early precordial transition with Rs or R in V2 or V3. Ventricular tachycardia from the left sinus had rS pattern in lead I, and VT from the noncoronary sinus had a notched R wave in lead I. None of the patients had complications and all remained arrhythmia-free at a mean follow-up of 8 +/- 2.6 months.

CONCLUSIONS

Normal heart VT with left bundle branch block, inferior axis and early precordial transition can be ablated in the majority of patients from either the left or the noncoronary aortic sinus of Valsalva.

The alterations of N-Methyl-D-aspartate receptor expressions and oxidative DNA damage in the CA1 area at the early time after ischemia-reperfusion insult

Delayed neuronal death in the CA1 of the hippocampus following global ischemia has been evoked by both the activation of N-methyl-D-aspartate receptor (NR) and the generate reactive oxygen species in the neurons. In the present study, we investigated whether oxidative DNA damages may be correlated with NR subunits (NR1 and NR2A/B) expression following ischemia insults in vivo. Thirty minutes after ischemia-reperfusion, the intensities of both NR and 8-hydroxy-2'-deoxyguanosine (8-OHdG) immunoreactivities were markedly increased in neurons of CA1. However, NR2A/B and 8-OHdG immunoreactivities were enhanced in CA1 over 24 h after ischemia although NR1 immunoreactivity was decreased. These results suggest that oxidative stress and excitotoxicity in the CA1 may simultaneously trigger neuronal damages at early time after ischemia, and free radical damage including oxidative DNA damage may eventually promote the delayed neuronal death in this region.

Ratio of jet cross sections at square root of s = 630 GeV and 1800 GeV

The D0 Collaboration has measured the inclusive jet cross section in barpp collisions at square root of s = 630 GeV. The results for pseudorapidities (eta)<0.5 are combined with our previous results at square root of s = 1800 GeV to form a ratio of cross sections with smaller uncertainties than either individual measurement. Next-to-leading-order QCD predictions show excellent agreement with the measurement at 630 GeV; agreement is also satisfactory for the ratio. Specifically, despite a 10% to 15% difference in the absolute magnitude, the dependence of the ratio on jet transverse momentum is very similar for data and theory.

Ratios of multijet Cross Sections in p p collisions at radical(s) = 1.8 TeV

We report on a study of the ratio of inclusive three-jet to inclusive two-jet production cross sections as a function of total transverse energy in p&pmacr; collisions at a center-of-mass energy sqrt[s] = 1.8 TeV, using data collected with the D0 detector during the 1992-1993 run of the Fermilab Tevatron Collider. The measurements are used to deduce preferred renormalization scales in perturbative O(alpha(3)(s)) QCD calculations in modeling soft-jet emission.

Inclusive jet production in pp(macro) collisions

We report a new measurement of the pseudorapidity (eta) and transverse-energy ( E(T)) dependence of the inclusive jet production cross section in pp(macro) collisions at square root of s = 1.8 TeV using 95 pb(-1) of data collected with the D0 detector at the Fermilab Tevatron. The differential cross section d(2)sigma/(dE(T)d eta) is presented up to eta = 3, significantly extending previous measurements. The results are in good overall agreement with next-to-leading order predictions from QCD and indicate a preference for certain parton distribution functions.

Search for large extra dimensions in dielectron and diphoton production

We report a search for effects of large extra spatial dimensions in pp collisions at a center-of-mass energy of 1.8 TeV with the D0 detector, using events containing a pair of electrons or photons. The data are in good agreement with the expected background and do not exhibit evidence for large extra dimensions. We set the most restrictive lower limits to date, at the 95% C.L. on the effective Planck scale between 1.0 and 1.4 TeV for several formalisms and numbers of extra dimensions.

Net amino acid flux across the fetal liver and placenta during spontaneous ovine parturition

The uptake and/or release of amino acids across the fetal liver and the placenta were studied in 8 pregnant sheep during the 5 days preceding delivery of the lamb. During spontaneous parturition, there was a significant decrease in fetal hepatic glutamine uptake, in fetal hepatic glutamate release and in placental glutamate uptake. The fetal plasma concentrations of glutamate, leucine, isoleucine, valine, phenylalanine, serine and tyrosine also decreased significantly in the 5 days preceding delivery. There was no significant net output of glucose from the fetal liver nor any change in net lactate uptake by the liver. During this same time period there was a significant increase in the fetal plasma cortisol concentration and a decrease in progesterone output by the pregnant uterus. The results are compared to the previously reported amino acid changes during dexamethasone-induced parturition.

Archaic strains of methicillin-resistant Staphylococcus aureus: molecular and microbiological properties of isolates from the 1960s in Denmark

Methicillin-resistant Staphylococcus aureus (MRSA) isolated in the 1960s in Denmark are among the historically earliest samples of these bacteria. We determined microbiological and molecular properties of 46 such isolates. They showed remarkably uniform properties, which included: (i) low methicillin MIC value (6-25 microg/ml); (ii) heterogeneous expression of resistance; (iii) the presence of a single, common, mecA polymorph II; (iv) lack of the regulatory gene mecI; (v) frequent lack of Tn554; and (vi) a common pulsed-field gel electrophoresis (PFGE) type. These properties, together with the chronological dates of isolation, and recovery of the strains from 18 hospitals scattered over Denmark, suggest that they represent a lineage close in time to the evolutionary origin of European strains of MRSA.

Radiofrequency ablation of 231 unresectable hepatic tumors: indications, limitations, and complications

BACKGROUND

Radiofrequency ablation (RFA) is increasingly used for the local destruction of unresectable hepatic malignancies. There is little information on its optimal approach or potential complications.

METHODS

Since late 1997, we have undertaken 91 RFA procedures to ablate 231 unresectable primary or metastatic liver tumors in 84 patients. RFA was performed via celiotomy (n = 39), laparoscopy (n = 27), or a percutaneous approach (n = 25). Patients were followed with spiral computed tomographic (CT) scans at 1 to 2 weeks postprocedure and then every 3 months for 2 years.

RESULTS

Intraoperative ultrasound (IOUS) detected intrahepatic disease not evident on the preoperative scans of 25 of 66 patients (38%) undergoing RFA via celiotomy or laparoscopy. In 38 of 84 patients (45%), RFA was combined with resection or cryosurgical ablation (CSA), or both. RFA was used to treat an average of 2.8 lesions per patient, and the median size of treated lesions was 2 cm (range, 0.3-9 cm). The average hospital stay was 3.6 days overall (1.8 days for percutaneous and laparoscopic cases). Ten patients underwent a second RFA procedure (sequential ablations) and, in one case, a third RFA procedure for large (one patient), progressive (seven patients), and/or recurrent (three patients) lesions. Seven (8%) patients had complications: one skin burn; one postoperative hemorrhage; two simple hepatic abscesses; one hepatic abscess associated with diaphragmatic heat necrosis following sequential percutaneous ablations of a large lesion; one postoperative myocardial infarction; and one liver failure. There were three deaths, one (1%) of which was directly related to the RFA procedure. Three of the complications, including one RFA-related death, occurred after percutaneous RFA. At a median follow-up of 9 months (range, 1-27 months), 15 patients (18%) had recurrences at an RFA site, and 36 patients (43%) remained clinically free of disease.

CONCLUSIONS

Celiotomy or laparoscopic approaches are preferred for RFA because they allow IOUS, which may demonstrate occult hepatic disease. Operative RFA also allows concomitant resection, CSA, or placement of a hepatic artery infusion pump, and isolation of the liver from adjacent organs. Percutaneous RFA should be reserved for patients at high risk for anesthesia, those with recurrent or progressive lesions, and those with smaller lesions sufficiently isolated from adjacent organs. Complications may be minimized when these approaches are applied selectively.

Cloning and characterization of bovine stearoyl CoA desaturasel cDNA from adipose tissues

Two overlapping cDNA clones have been isolated from bovine adipose tissue by the reverse-transcription-polymerase chain reaction (RT-PCR) method. The combined sequence of the two clones was 1039 bp in length and encoded 345 amino acids. The deduced amino acid sequence of the clones showed 96.5% similarity to that of sheep SCD and more than 88% similarities to other mammalian SCD1s, indicating that the clones are the cDNAs for the bovine SCD1. The transcript size of the bovine SCD1 was about 4.9 kb, the message was detected in the bovine adipose tissues but not in the liver. Female cattle expressed threefold higher levels of SCD1 mRNA than male animals.

Probing Balitsky-Fadin-Kuraev-Lipatov dynamics in the dijet cross section at large rapidity intervals in pp collisions at sqrt[s]=1800 and 630 GeV

Inclusive dijet production at large pseudorapidity intervals (Deltaeta) between the two jets has been suggested as a regime for observing Balitsky-Fadin-Kuraev-Lipatov (BFKL) dynamics. We have measured the dijet cross section for large Deltaeta in pp collisions at sqrt[s]=1800 and 630 GeV using the D0 detector. The partonic cross section increases strongly with the size of Deltaeta. The observed growth is even stronger than expected on the basis of BFKL resummation in the leading logarithmic approximation. The growth of the partonic cross section can be accommodated with an effective BFKL intercept of alphaBFKL(20 GeV)=1.65+/-0.07.

Measurement of the W-->taunu production cross section in pp collisions at square root s=1.8 TeV

We report on a measurement of sigma(pp-->W+X)B(W-->taunu) in pp collisions at sqrt[s]=1.8 TeV at the Fermilab Tevatron. The measurement is based on an integrated luminosity (lum) of 18 pb-1 of data collected with the D0 detector during 1994-1995. We find that sigma(pp-->W+X)B(W-->taunu)=2.22+/-0.09 (stat)+/-0. 10 (syst)+/-0.10 (lum) nb. Lepton universality predicts that the ratio of the tau and electron electroweak charged current couplings to the W boson, gWtau/gWe, be unity. We find gWtau/gWe=0.980+/-0.031, in agreement with lepton universality.

Cryosurgical ablation and radiofrequency ablation for unresectable hepatic malignant neoplasms: a proposed algorithm

BACKGROUND

Thermal ablation of unresectable hepatic tumors can be achieved by cryosurgical ablation (CSA) or radiofrequency ablation (RFA). The relative advantages and disadvantages of each technique have not yet been determined.

HYPOTHESIS

Radiofrequency ablation of malignant hepatic neoplasms can be performed safely, but is currently limited by size. Cryosurgical ablation, while associated with higher morbidity, is more effective for larger unresectable hepatic malignant neoplasms.

DESIGN

Retrospective analysis of prospective patient database.

PATIENTS AND METHODS

Between July 1992 and September 1999, 308 patients with liver tumors not amenable to curative surgical resection were treated with CSA and/or RFA (percutaneous, laparoscopic, celiotomy). No patient had preoperative evidence of extrahepatic disease. All patients underwent laparoscopy with intraoperative ultrasound if technically possible. Both RFA and CSA were performed under ultrasound guidance. Resection, as an adjunctive procedure, was combined with ablation in certain patients.

RESULTS

Laparoscopy identified extrahepatic disease in 12% of patients, and intraoperative hepatic ultrasound identified additional lesions in 33% of patients, despite extensive preoperative imaging. Radiofrequency ablation alone or combined with resection or CSA resulted in reduced blood loss (P<.05), thrombocytopenia (P<.05), and shorter hospital stay compared with CSA alone (P<.05). Median ablation times for lesions greater than 3 cm were 60 minutes with RFA and 15 minutes with CSA (P<.001). Local recurrence rates for lesions greater than 3 cm were also greater with RFA (38% vs 17%).

CONCLUSIONS

Laparoscopy and intraoperative ultrasound are essential in staging patients with hepatic malignant neoplasms. Radiofrequency ablation when combined with CSA reduces the morbidity of multiple freezes. Although RFA is safer than CSA and can be performed via different approaches (percutaneously, laparoscopically, or at celiotomy), it is limited by tumor size (<3 cm). Percutaneous RFA should be considered in high-risk patients or those with small local recurrences.

The Breast Health Center at Women & Infants Hospital: origin, philosophy, and features

The Breast Health Center, a component of the program in Women's Oncology at Women & Infants Hospital, is a multidisciplinary center devoted to the treatment and study of benign and malignant breast diseases. The philosophy, structure, and function of The Breast Health Center are described along with its specific components. The Breast Health Center's three fundamental missions of patient care, education, and research are discussed.

Role of transposon Tn5482 in the epidemiology of vancomycin-resistant Enterococcus faecium in the pediatric oncology unit of a New York City Hospital

During a 36-month period between 1993 and 1995 in the Pediatric Oncology Unit of Memorial Sloan Kettering Cancer Center, 74 patients experienced episodes of infection or colonization caused by vancomycin-resistant enterococci (VRE). Characterization of the 74 bacterial isolates by microbiological and molecular techniques (pulsed-field gel electrophoresis and hybridization with DNA probes specific for the vanA and vanB genes and for IS1251) identified 73 Enterococcusfaecium and one Enterococcusfaecalis (vanB) among the primary VRE isolates. Most (69/73) of the E. faecium isolates carried vanA and four isolates, the vanB gene complex. The overwhelming majority (67/69) of the vanA -positive isolates also gave hybridization signal for IS1251, indicating the presence of the newly described conjugative transposon Tn5482. No hybridization with IS1251 was obtained with the four vanB-carrying isolates. About 30% of the vanA-positive strains (23/69) were represented by PFGE subtype variants of a single clone, most isolates of which were recovered during a 4-month period between April to June of 1994. The larger portion of the vanA-carrying VRE represented by close to 70% of the isolates (46/69) belonged to as many as 37 different clonal types, indicating tremendous genetic diversity. Among 67 of the 69 vanA-carrying isolates, the localization of the Tn5482-associated vanA gene complex could be unequivocally identified either on the chromosome (40/69) or in plasmids (27/69). Transconjugants recovered from filter mating experiments using either a chromosomally located or plasmid-borne vanA donor strain and a single vancomycin-susceptible strain of either E. faecium or E. faecalis were analyzed by molecular typing techniques. Seven out of 10 independent transconjugants recovered from the same cross showed extensive differences in PFGE pattern and also in the localization of the vanA hybridizing DNA fragment transferred from the common VRE donor with chromosomally located vanA. The observations suggest that the extensive genetic diversity observed among the clinical isolates of VRE may be generated during conjugation between vancomycin-resistant and -susceptible enterococcal isolates. The observations also suggest that the epidemic spread of VRE in the United States may be linked to the frequent presence of Tn5482 among the American isolates.

Spread of the multiresistant Iberian clone of methicillin-resistant Staphylococcus aureus (MRSA) to Italy and Scotland

The multidrug-resistant "Iberian" clone of methicillin-resistant Staphylococcus aureus (MRSA) was first identified on the basis of its unique DNA fingerprints as the strain responsible for the massive 1989 outbreak of MRSA disease in the hospital Princeps d'Espanya, Barcelona, Spain. Most Iberian MRSA carry a constitutive beta-lactamase. They are resistant to most beta-lactam antibiotics, macrolides, aminoglycosides, tetracycline, rifampin and ciprofloxacin and are susceptible to fosfomycin, fusidic acid, mupirocin, sulfamethoxazole/trimethoprim and vancomycin. The characteristic DNA fingerprints of the clone include the mecA polymorph I, Tn554 pattern E (or its variants), a chromosomal macrorestriction pattern (pulsed-field gel electrophoretic type) A (or its subtype variants), the lack of the mecI regulatory gene and a homogeneous, high level of expression of methicillin resistance. Molecular surveillance studies have documented the extensive spread of this clone to many Portuguese hospitals during the 1990s. In this article, we describe the spread of the Iberian MRSA to hospitals in Rome, Italy, and Scotland.

Antibiotic resistance as a stress response: complete sequencing of a large number of chromosomal loci in Staphylococcus aureus strain COL that impact on the expression of resistance to methicillin

Tn551 inactivation has identified several determinants--fem or auxiliary genes--that, in addition to the mecA gene, are also critical for the expression of high-level and homogeneous resistance to methicillin. Genetic and/or biochemical analysis has shown that of the nearly dozen aux mutations described so far most are in genes involved in cell wall synthesis (murE, pbp2, glmM, glnR, femA/B, llm, etc.) or in complex regulatory functions (sigmaB), suggesting that optimal expression of resistance may involve the cooperative functioning of a number of genes in cell wall metabolism as well as stress response. The exact mechanism of these functions is not known. In an attempt to explore this unusual aspect of methicillin resistance more fully, a Tn551 transposon library, constructed in the background of the highly and homogeneously methicillin-resistant Staphylococcus aureus strain COL, was screened for all independent insertional mutants in which the level of methicillin resistance of the parental strain (MIC, 1,600 microg/ml) was reduced by at least 15-fold and up to 500-fold. We now describe the sequencing of 21 Tn551-inactivated genes and their vicinities in 23 new auxiliary mutants that have been studied before. Using the inverted polymerase chain reaction (IPCR), we amplified fragments corresponding to the right and left junction of the Tn551 insertions, which were then sequenced by primer walking. The two largest groups of these new auxiliary genes encoded either proteins of unknown functions (6 genes) or showed homology with genes encoding proteins involved with putative sensory/regulatory activities (7 genes: protein kinases, ABC transporters, and a catabolite control protein). Sequencing upstream and downstream allowed the identification of a number of additional open reading frames, some of which may also include functions relevant for the expression of antibiotic resistance.

B7.1 costimulation increases T-cell proliferation and cytotoxicity via selective expansion of specific variable alpha and beta genes of the T-cell receptor

BACKGROUND

Optimal T-cell activation requires not only ligation of the T-cell receptor (TcR) but also delivery of costimulatory signals by various accessory molecules. The interaction of the costimulatory molecule B7.1 (CD80) with its receptor CD28 provides a strong positive signal to T cells.

METHODS

The B7.1 gene was transduced into cultured human ovarian, breast, and pancreatic tumor cells by using a retroviral vector. Autologous as well as allogeneic naive T-cells were stimulated with either wild-type or B7.1-transduced tumor cells in a mixed lymphocyte tumor cell culture (MLTC). In addition to cytolytic activity, T-cell proliferation, T-cell subset composition, and the frequencies of TcR variable (V) alpha and beta genes were compared in T cells from both types of MLTC.

RESULTS

Introduction of the B7.1 gene into tumor cells was successful in all tumors to a varying degree. Those tumors expressing high levels of B7.1 induced significantly higher levels of T-cell proliferation than wild-type tumor cells. T-cell subset composition did not markedly differ between T cells stimulated with wild-type tumor cells or B7.1-expressing tumor cells. However, T cells stimulated with B7.1-expressing tumor cells showed a significantly increased cytolytic potential. The increased cytotoxic T lymphocyte activity was associated with a higher frequency of specific TcR V alpha and V beta genes. In addition, B7.1 costimulation promoted oligoclonality among the responding T cells.

CONCLUSIONS

These data suggest that costimulation through B7.1 promotes T-cell proliferation and cytotoxic activity through clonal expansions of T cells bearing antigen-specific TcR V alpha and V beta genes and through promotion of oligoclonality. The data also suggest that promoting B7.1-mediated costimulation is an important aspect of immune therapies.

Clinical diversity of hereditary Duane's retraction syndrome

OBJECTIVE

To define the spectrum of ophthalmic manifestations of Duane's retraction syndrome (DRS) in a large family.

DESIGN

Cross-sectional study of 110 among 114 living relatives in an extended family.

METHODS

History and ophthalmic examination obtained on all participants.

MAIN OUTCOME MEASURES

Ocular motility, strabismus, visual acuity, binocularity, associated neurologic problems.

RESULTS

Twenty-five individuals were affected with DRS. Twenty-four subjects (96%) had bilateral DRS, but there was a broad spectrum of severity. Strabismus occurred in 76% and amblyopia in 48%. Associated findings included fourth cranial nerve palsy, partial third cranial nerve palsy, nystagmus, seizures, and deafness. Fourth cranial nerve palsies and manifest strabismus tended to cluster within single family units.

CONCLUSIONS

Strabismus and amblyopia are much more common with bilateral DRS than with unilateral DRS. There is much phenotypic variability among individuals within families with hereditary Duane's syndrome. The responsible gene(s) may affect the development of many cranial nerves. Genetic compounding may play a role in the phenotypic segregation seen within this large family.

The Cox-Maze procedure: the Cleveland Clinic experience

The Cox-Maze procedure was designed to address the consequences of atrial fibrillation, tachycardia, hemodynamic impairment, and thromboembolism. From 1991 until June 1999, 100 patients underwent the Maze operation at the Cleveland Clinic Foundation. The group included 72 men with a mean age of 58 +/- 11 years (range, 23 to 78 years). Initially, the Maze-I procedure was performed primarily for patients with lone atrial fibrillation. However, since 1995, the Maze-III procedure has been performed exclusively, and it is typically combined with mitral valve repair. Twenty-three patients had only a Maze procedure, 60 patients had the Maze procedure/mitral valve repair, 10 patients had Maze procedure/coronary artery bypass, 6 had Maze procedure/mitral valve replacement, and 1 had Maze procedure/atrial septal defect repair. Chronic atrial fibrillation was present in 78% of patients for a mean of 8 +/- 9 years. There was a 1% perioperative mortality and 5% late mortality rate. Median hospital stay was 9 +/- 5 days. Six patients required new early permanent pacemaker insertion. With a mean follow-up of 3 years, 90.4% of patients are in sinus rhythm (or atrial pacing). Preoperative symptoms were reduced: 24% had preoperative syncope; none had syncope in follow-up; 14% of patients preoperatively had cerebral or systemic emboli; and there were no perioperative or late embolic events. The Maze procedure effectively addressed the major complications of atrial fibrillation and was associated with low perioperative and late morbidity rates.

The effects of hepatic impairment on the pharmacokinetics of doxazosin

The pharmacokinetics of doxazosin was determined in an open-label study of 12 male volunteers with hepatic impairment (stable alcoholic cirrhosis) and 12 healthy male volunteers. Participants (fasting) received a single 2 mg doxazosin tablet, and blood samples were collected over a 120-hour period. Safety assessments included laboratory and vital sign (blood pressure, pulse rate, and ECGs) measurements and recording of all reported adverse events. The mean peak plasma concentrations were 10.8 ng/mL and 12.3 ng/mL for the subjects with hepatic impairment and healthy subjects, respectively. The corresponding mean area under the plasma concentration-time curve values were 246 and 172 ng.h/mL, a 43% increase in exposure in the subjects with hepatic impairment (p = 0.02). Although the apparent oral clearance was reduced by 30% in men with hepatic impairment compared with healthy subjects (p = 0.02), the elimination halflife was not significantly changed (24 vs. 22 hours, respectively). Laboratory test results, vital signs, and the incidence of adverse events were similar for the two treatment groups. These findings indicate that the recommended dosing regimen for doxazosin is appropriate for patients with clinically mild to moderate hepatic impairment.