NF-κB-mediated effects on behavior and cartilage pathology in a non-invasive loading model of post-traumatic osteoarthritis.

OBJECTIVE: This study aimed to examine the temporal activation of NF-κB and its relationship to the development of pain-related sensitivity and behavioral changes in a non-invasive murine knee loading model of PTOA. METHOD: Following knee injury NF-κB activity was assessed longitudinally via in vivo imaging in FVB. Cg-Tg (HIV-EGFP,luc)8Tsb/J mice. Measures of pain-related sensitivity and behavior were also assessed longitudinally for 16 weeks. Additionally, we antagonized NF-κB signaling via intra-articular delivery of an IκB kinase two antagonist to understand how local NF-κB inhibition might alter disease progression. RESULTS: Following joint injury NF-κB signaling within the knee joint was transiently increased and peaked on day 3 with an estimated 1.35 p/s/cm2/sr (95% CI 0.913.1.792 p/s/cm2/sr) fold increase in signaling when compared to control joints. Furthermore, injury resulted in the long-term development of hindpaw allodynia. Hyperalgesia withdrawal thresholds were reduced at injured knee joints, with the largest reduction occurring 2 days following injury (estimate of between group difference 129.1 g with 95% CI 60.9,197.4 g), static weight bearing on injured limbs was also reduced. Local delivery of an NF-κB inhibitor following joint injury reduced chondrocyte death and influenced the development of pain-related sensitivity but did not reduce long-term cartilage degeneration. CONCLUSION: These findings underscore the development of behavioral changes in this non-invasive loading model of PTOA and their relationships to NF-κB activation and pathology. They also highlight the potential chondroprotective effects of NF-κB inhibition shortly following joint injury despite limitations in preventing the long-term development of joint degeneration in this model of PTOA.

Bilateral Neonatal Suppurative Sialadenitis Progressing to Abscess Formation in a Preterm Neonate

Aims We report a case of bilateral neonatal suppurative sialadenitis (NSS) in an extremely low birth weight infant (ELBW). Methods The infant developed bilateral sub-mandibular swelling at 3 weeks of age. NSS with abscess was confirmed with ultrasound. Despite intravenous antibiotic therapy the masses increased in size and developed abscesses. Results Unilaterally the abscess discharged via Wharton's duct necessitating intubation to protect the airway. The abscess remnant was incised and drained. Culture grew a methicillin sensitive staphyloccocus aureus. The NSS resolved following two weeks of antibiotics. Conclusion We wish to highlight the importance of early recognition of this rare condition in preterm neonates.

Epidemiology of systematic reviews in imaging journals: evaluation of publication trends and sustainability?

PURPOSE: To evaluate the epidemiology of systematic reviews (SRs) published in imaging journals. METHODS: A MEDLINE search identified SRs published in imaging journals from 1 January 2000-31 December 2016. Articles retrieved were screened against inclusion criteria. Demographic and methodological characteristics were extracted from studies. Temporal trends were evaluated using linear regression and Pearson's correlation coefficients. RESULTS: 921 SRs were included that reported on 27,435 primary studies, 85,276,484 patients and were cited 26,961 times. The SR publication rate increased 23-fold (r=0.92, p<0.001) while the proportion of SRs to non-SRs increased 13-fold (r = 0.94, p<0.001) from 2000 (0.10%) to 2016 (1.33%). Diagnostic test accuracy (DTA) SRs were most frequent (46.5%) followed by therapeutic SRs (16.6%). Most SRs did not report funding status (54.2%). The median author team size was five; this increased over time (r=0.20, p<0.001). Of the studies, 67.3% included an imaging specialist co-author; this decreased over time (r=-0.57, p=0.017). Most SRs included a meta-analysis (69.6%). Journal impact factor positively correlated with SR publication rates (r=0.54, p<0.001). Magnetic resonance imaging (MRI) and 'vascular and interventional radiology' were the most frequently studied imaging modality and subspecialty, respectively. The USA, UK, China, Netherlands and Canada were the top five publishing countries. CONCLUSIONS: The SR publication rate is increasing rapidly compared with the rate of growth of non-SRs; however, they still make up just over 1% of all studies. Authors, reviewers and editors should be aware of methodological and reporting standards specific to imaging systematic reviews including those for DTA and individual patient data. KEY POINTS: • Systematic review publication rate has increased 23-fold from 2000-2016. • The proportion of systematic reviews to non-systematic reviews has increased 13-fold. • The USA, UK and China are the most frequent published countries; those from the USA and China are increasing the most rapidly.

Iron Refractory Iron Deficiency Anaemia: A Rare Cause of Iron Deficiency Anaemia.

We describe the case of a 17-month-old boy with a hypochromic microcytic anaemia, refractory to oral iron treatment. After exclusion of dietary and gastrointestinal causes of iron deficiency, a genetic cause for iron deficiency was confirmed by finding two mutations in the TMPRSS6 gene, consistent with a diagnosis of iron-refractory iron deficiency anaemia (IRIDA).

Reporting bias in imaging: higher accuracy is linked to faster publication.

OBJECTIVES: The objective of this study was to evaluate whether higher reported accuracy estimates are associated with shorter time to publication among imaging diagnostic accuracy studies. METHODS: We included primary imaging diagnostic accuracy studies, included in meta-analyses from systematic reviews published in 2015. For each primary study, we extracted accuracy estimates, participant recruitment periods and publication dates. Our primary outcome was the association between Youden's index (sensitivity + specificity - 1, a single measure of diagnostic accuracy) and time to publication. RESULTS: We included 55 systematic reviews and 781 primary studies. Study completion dates were missing for 238 (30%) studies. The median time from completion to publication in the remaining 543 studies was 20 months (IQR 14-29). Youden's index was negatively correlated with time from completion to publication (rho = -0.11, p = 0.009). This association remained significant in multivariable Cox regression analyses after adjusting for seven study characteristics: hazard ratio of publication was 1.09 (95% CI 1.03-1.16, p = 0.004) per unit increase for logit-transformed estimates of Youden's index. When dichotomizing Youden's index by a median split, time from completion to publication was 20 months (IQR 13-33) for studies with a Youden's index below the median, and 19 months (14-27) for studies with a Youden's index above the median (p = 0.104). CONCLUSION: Imaging diagnostic accuracy studies with higher accuracy estimates were weakly associated with a shorter time to publication. KEY POINTS: • Higher accuracy estimates are weakly associated with shorter time to publication. • Lag in time to publication remained significant in multivariate Cox regression analyses. • No correlation between accuracy and time from submission to publication was identified.

Comparison of a PCR serotyping assay, Check&Trace assay for Salmonella, and Luminex Salmonella serotyping assay for the characterization of Salmonella enterica identified from fresh and naturally contaminated cilantro.

Salmonella enterica isolated from fresh cilantro samples collected through the USDA/AMS Microbiological Data Program (MDP) were used to compare a PCR serotyping assay against the Check&Trace assay and the Luminex (BioPlex) Salmonella serotyping assay. The study was conducted to evaluate the effectiveness of the three methods for serotyping Salmonella from both enrichment broth cultures and pure Salmonella cultures. In this investigation, Salmonella spp. serotyping was conducted using 24 h enrichment broth cultures and pure Salmonella cultures from cilantro samples, with the PCR serotyping assay. Conversely, the Check&Trace and Luminex for Salmonella assays required pure cultures for Salmonella serotyping. The cilantro samples contained S. enterica serovar Montevideo, Newport, Saintpaul, and Tennessee, identified by the PCR serotyping assay and Check&Trace for Salmonella, but the Luminex assay only identified two of the four serotypes of the cilantro samples. The anticipated impact from this study is that the PCR serotyping assay provides a time- and cost-effective means for screening, identifying and serotyping Salmonella using DNA extracted from 24 h enrichment cilantro samples.

Biosensors for the analysis of microbiological and chemical contaminants in food.

Increases in food production and the ever-present threat of food contamination from microbiological and chemical sources have led the food industry and regulators to pursue rapid, inexpensive methods of analysis to safeguard the health and safety of the consumer. Although sophisticated techniques such as chromatography and spectrometry provide more accurate and conclusive results, screening tests allow a much higher throughput of samples at a lower cost and with less operator training, so larger numbers of samples can be analysed. Biosensors combine a biological recognition element (enzyme, antibody, receptor) with a transducer to produce a measurable signal proportional to the extent of interaction between the recognition element and the analyte. The different uses of the biosensing instrumentation available today are extremely varied, with food analysis as an emerging and growing application. The advantages offered by biosensors over other screening methods such as radioimmunoassay, enzyme-linked immunosorbent assay, fluorescence immunoassay and luminescence immunoassay, with respect to food analysis, include automation, improved reproducibility, speed of analysis and real-time analysis. This article will provide a brief footing in history before reviewing the latest developments in biosensor applications for analysis of food contaminants (January 2007 to December 2010), focusing on the detection of pathogens, toxins, pesticides and veterinary drug residues by biosensors, with emphasis on articles showing data in food matrices. The main areas of development common to these groups of contaminants include multiplexing, the ability to simultaneously analyse a sample for more than one contaminant and portability. Biosensors currently have an important role in food safety; further advances in the technology, reagents and sample handling will surely reinforce this position.

Dynamic stretching and golf swing performance.

The aim of the present study was to examine the effect of dynamic stretching, static stretching and no stretching, as part of a general warm-up, on golf swing performance with a five-iron. Measures of performance were taken 0 min, 5 min, 15 min and 30 min after stretching. Dynamic stretching produced significantly greater club head speeds than both static stretching (Delta=1.9m.s (-1); p=0.000) and no stretching (Delta=1.7 m.s (-1); p=0.000), and greater ball speeds than both static stretching (Delta=3.5m.s (-1); p=0.003) and no stretching (Delta=3.3m.s (-1); p=0.001). Dynamic stretching produced significantly straighter swing-paths than both static stretching (Delta=-0.61 degrees , p=0.000) and no stretching (Delta=-0.72 degrees , p=0.01). Dynamic stretching also produced more central impact points than the static stretch (Delta=0.7 cm, p=0.001). For the club face angle, there was no effect of either stretch or time. For all of the variables measured, there was no significant difference between the static stretch and no stretch conditions. All of the results were unaffected by the time of measurement after stretching. The results indicate that dynamic stretching should be used as part of a general warm-up in golf.

Synthesis and reactivity of the monocarbon molybdenacarborane anion [1,2-mu-NHBu(t)-2,2,2-(CO)(3)-closo-2,1-MoCB(10)H(10)](-).

The reagent Li[7-NHBu(t)()-nido-7-CB(10)H(12)] reacts with [Mo(CO)(6)] in NCMe at reflux temperatures, followed by addition of [N(PPh(3))(2)]Cl, to give [N(PPh(3))(2)][1,2-mu-NHBu(t)-2,2,2-(CO)(3)-closo-2,1-MoCB(10)H(10)] (1). The tungsten (2) and chromium (3) analogues were similarly obtained, but the latter is unstable and was isolated in low yield. An X-ray diffraction study of 2 confirmed that the exo-polyhedral NHBu(t) group forms a bridge between the cage-carbon atom and the tungsten. For 1, this intramolecular donor bond is lifted on protonation in the presence of donor molecules L (CO, PPh(3), PMe(3), PEt(3), PMe(2)Ph) when zwitterionic complexes [1-NH(2)Bu(t)()-2,2,2-(CO)(3)-2-L-closo-2,1-MoCB(10)H(10)] (4) are formed. In contrast, protonation with HCl gives a salt [N(PPh(3))(2)][1-NH(2)Bu(t)()-2,2,2-(CO)(3)-2-Cl-closo-2,1-MoCB(10)H(10)] (5). Complex 1 in CH(2)Cl(2) with CNBu(t) is oxidized by iodine, affording [1,2-mu-NHBu(t)()-2,2,2-(CNBu(t)())(3)-2-I-closo-2,1-MoCB(10)H(10)] (6a). Treatment of 1 with [CuCl(PPh(3))](4) in the presence of Tl[PF(6)] yields the bimetallic compound [exo-[Cu(PPh(3))]-1,2-mu-NHBu(t)-2,2,2-(CO)(3)-closo-2,1-MoCB(10)H(10)] (8), whereas reaction with [AuCl(PPh(3))] and Tl[PF(6)] affords a mixture of [1,2-mu-NHBu(t)-2-[Au(PPh(3))]-2,2,2-(CO)(3)-closo-2,1-MoCB(10)H(10)] (9) and [Au(PPh(3))(2)][2,2'-mu-Au-[1,2-mu-NHBu(t)-2,2,2-(CO)(3)-closo-2,1-MoCB(1)(0)H(10)](2)] (10a). In solution, 9 disproportionates, giving 10a. The [N(PPh(3))(2)](+) salt (10b) is readily prepared by treating 1 with [AuCl(THT)] (THT = tetrahydrothiophene) and Tl[PF(6)], and its structure was determined by X-ray diffraction.

Identification of chromosome inheritance modifiers in Drosophila melanogaster.

Faithful chromosome inheritance is a fundamental biological activity and errors contribute to birth defects and cancer progression. We have performed a P-element screen in Drosophila melanogaster with the aim of identifying novel candidate genes involved in inheritance. We used a "sensitized" minichromosome substrate (J21A) to screen approximately 3,000 new P-element lines for dominant effects on chromosome inheritance and recovered 78 Sensitized chromosome inheritance modifiers (Scim). Of these, 69 decreased minichromosome inheritance while 9 increased minichromosome inheritance. Fourteen mutations are lethal or semilethal when homozygous and all exhibit dramatic mitotic defects. Inverse PCR combined with genomic analyses identified P insertions within or close to genes with previously described inheritance functions, including wings apart-like (wapl), centrosomin (cnn), and pavarotti (pav). Further, lethal insertions in replication factor complex 4 (rfc4) and GTPase-activating protein 1 (Gap1) exhibit specific mitotic chromosome defects, discovering previously unknown roles for these proteins in chromosome inheritance. The majority of the lines represent mutations in previously uncharacterized loci, many of which have human homologs, and we anticipate that this collection will provide a rich source of mutations in new genes required for chromosome inheritance in metazoans.

Hazardous air pollutant emissions from gas-fired combustion sources: emissions and the effects of design and fuel type.

Air emissions from gas-fired combustion devices such as boilers, process heaters, gas turbines and stationary reciprocating engines contain hazardous air pollutants (HAPs) subjected to consideration under the federal clean air act (CAA). This work presents a recently completed major research project to develop an understanding of HAP emissions from gas-fired boilers and process heaters and new HAP emission factors based on field emission tests of gas-fired external combustion devices used in the petroleum industry. The effect of combustion system design and operating parameters on HAP emissions determined by both field and research tests are discussed. Data from field tests of gas-fired petroleum industry boilers and heaters generally show very low emission levels of organic HAPs. A comparison of the emission data for boilers and process heaters, including units with and without various forms of NOx emission controls, showed no significant difference in organic HAP emission characteristics due to process or burner design. This conclusion is also supported by the results of research tests with different burner designs. Based on field tests of units fired with natural gas and various petroleum industry process gases and research tests in which gas composition was intentionally varied, organic HAP emissions were not determined to be significantly affected by the gas composition. Research data indicate that elevated organic HAP emission levels are found only under extreme operating conditions (starved air or high excess air combustion) associated with poor combustion.

The timing of parturition in the pig is altered by intravenous naloxone.

This experiment tested the hypothesis that opioid antagonists could influence the timing of the onset and progress of parturition in the pig. Primiparous pigs (gilts) received a jugular catheter on Days 104 to 106 of pregnancy. At 1400 h on Day 112 the gilts received 10 mg PGF2alpha, i.m. to induce parturition. At 1000 h on Day 113 (i.e., 20 h later) gilts received either saline (n=6), 1 mg/kg, i.v. naltrexone (n=4) or 1 mg/kg, i.v. naloxone (n=5). Blood samples were taken daily from Days 108 to 116. On Day 113, blood samples were taken hourly from 0500 to 0900 h and then every 30 min until 2400 h, or until the birth of the last piglet (BLP) (whichever was sooner) and assayed for progesterone, oxytocin (OT), cortisol and PRL. Additional blood samples for OT and cortisol assay were taken every minute from 0930 to 1100 h on Day 113 and for 30 min during parturition. Naloxone, but not naltrexone, delayed the onset of parturition relative to saline controls (by 14 h 21 min; P<0.05). Duration of parturition and rate of births were not significantly affected by treatment. Mean plasma OT increased in the 4 h following naloxone but not saline treatment, during which time OT plasma pulse amplitude was reduced in naloxone and naltrexone-treated animals relative to saline treated controls. The PRL secretion rose following treatment in saline treated animals, consistent with approaching parturition, but failed to rise in opioid antagonist treated animals. Progesterone concentrations remained elevated in naloxone-treated animals for longer than in the other groups. These data suggest that a rapid change in overall effect of parenteral administration of naloxone to parturient pigs occurs from delaying its onset when administered as in these experiments, to facilitating its progress when given during parturition (earlier experiments). The delay of onset of parturition may be mediated by interference with hypothalamic control of OT or PRL release.

Restricting maternal space during parturition in the pig. Effects on oxytocin, vasopressin and cortisol secretion following vagino-cervical stimulation and administration of naloxone.

This experiment studied the effects on endocrine and birth parameters of parturient pigs produced by restricting maternal freedom of movement without otherwise altering environment. Six primiparous pigs (gilts) were each given a jugular catheter under anaesthesia 7 days before parturition and commenced birth in a strawed pen, 2.0 m x 1.5 m in size. Continuous automated blood sampling (3 ml min-1) from unrestrained gilts began following the birth of the first piglet (stage 1) and continued for 2 h. After at least 30 min of blood collection, maternal space was reduced to 2.0 m x 0.55 m by placing rails across the pen (stage 2). The scope for movement in stage 2 was similar to that offered by a farrowing crate. After at least 25 min each gilt was given the opioid antagonist naloxone (1 mg kg-1 i.v.: stage 3). At each stage, vagino-cervical stimulation (VCS) was applied to mimic foetal ejection. Non-cervically stimulated oxytocin (OT) secretion between stages 1 and 2 was unchanged (P > 0.05) but increased significantly relative to both stages 1 and 2 following naloxone treatment for 15-20 min (P < 0.05, paired t-tests on log10 data). Following VCS in all stages plasma OT rose (P < 0.05) for 1-2 min in a similar way to that seen previously following foetal ejection, the increases being proportionally similar irrespective of stage or baseline secretion. Cortisol secretion did not increase as a consequence of space restriction (mean +/- SEM concentrations were 28.6 +/- 8.51 pmol l-1 and 32.3 +/- 11.8 pmol l-1 in stages 1 and 2, respectively). In addition, VCS did not significantly affect cortisol output. Lysine vasopressin concentrations were not affected as a consequence of either stage or VCS. Parturition was not interrupted following space restriction of gilts. These data suggest that reducing maternal space allowance during parturition is not stressful when the process does not involve the movement of animals to novel surroundings.

Changes in content of mRNA encoding oxytocin in the pig uterus during the oestrous cycle, pregnancy, at parturition and in lactational anoestrus.

The aim of this study was to show that the pig uterus synthesizes oxytocin. Uteri were obtained from 2-7 pigs at regular intervals during the oestrous cycle, throughout pregnancy, at parturition and in lactational anoestrus. Localization of mRNA encoding oxytocin was by in situ hybridization and oxytocin concentrations were measured by radioimmunoassay. As reproductive status changed, mRNA encoding oxytocin varied significantly (P < 0.05). Uterine tissue type was a significant factor in determining synthesis of mRNA encoding oxytocin (P < 0.001). In luminal epithelia, concentrations of mRNA encoding oxytocin were greater at oestrus than during day 14 of the luteal phase (P < 0.01) or at any stage of pregnancy (P < 0.05), with concentrations minimal at parturition. This trend was also exhibited in uterine circular muscle. In longitudinal muscle, concentrations of mRNA encoding oxytocin were lower during late pregnancy than at oestrus (P < 0.05) or during the luteal phase (P < 0.05). Concentrations were minimal at parturition. The oxytocin content in endometrial and myometrial tissue was positively correlated across reproductive status (P < 0.02, r = 0.402, n = 35). These data are the first indication that the uterine endometrium and musculature of the pig express mRNA encoding oxytocin. The luminal epithelium of animals at oestrus was particularly rich in mRNA encoding oxytocin, whilst late pregnant and parturient animals did not show a rise in mRNA encoding oxytocin. Local uterine synthesis of oxytocin may therefore be more important in control of the oestrous cycle than in pregnancy or at parturition in pigs.

Pulsatile secretion of oxytocin during parturition in the pig: temporal relationship with fetal expulsion.

1. To assess changes in oxytocin release as they occur in relation to the rapid progress of events at fetal expulsion, continuous automated blood withdrawals (3 ml min-1) from an indwelling jugular catheter and intramammary pressure recordings were obtained from nine primiparous pigs (190-220 kg). Data were acquired over 16 h of normal parturition, during which thirty-five piglets were born. 2. Oxytocin secretion during parturition, when measured by radioimmunoassay (RIA) in blood collected and pooled every minute, showed a baseline secretion (19.8-88.37 pg ml-1) that was raised relative to preterm values. Analysis of individual secretion profiles revealed significant fluctuations or peaks of concentration superimposed on this baseline, with a slow periodicity of 4-12 min. These substantial peaks in secretion were not temporally related to fetal expulsion or visible abdominal contractions. 3. A small (13%) but significant increase in plasma oxytocin was also seen when assay data from the minutes coinciding with a birth were meaned and compared with the following minutes. This rise did not persist into further minutes. 4. Intramammary pressure recordings revealed a highly repeatable and characteristic phenomenon in that fetal expulsion was followed after 33.74 +/- 1.31 s (mean +/- S.E.M. time from emergence of fetus to peak pressure rise) in thirty-three of thirty-five instances by a distinctive and rapid bolus release of oxytocin. These 'postpartum oxytocin pulses' could be closely mimicked by injections of exogenous oxytocin (0.03-1.0 ng kg-1; lag time from jugular injection to peak pressure rise, 20.44 +/- 0.99 s). The timing of this event coincided with the small postpartum pulse measurable by radioimmunoassay.(ABSTRACT TRUNCATED AT 250 WORDS)

Reaching poor populations with cancer prevention and early detection programs.

The American Cancer Society (ACS), Philadelphia Division, through its Nurses' Education Committee (NEC), accepted the challenge to provide cancer prevention and early detection programs to several culturally diverse populations to directly reach the underserved, the working poor, and healthcare professionals who care for the poor. Populations selected included (1) students enrolled in nursing-assistant programs, (2) committed members of the ACS's NEC, (3) registered nurses employed by the local department of public health, and (4) a group of female immigrants from Russia.

Regulation of the B cell immune response: induction of competence and progression in a surface IgM-bearing subset.

We have targeted the specific surface IgM-bearing subset of human B lymphocytes within a mixed population and investigated cell cycle activation in these cells stimulated with phorbol ester and antibody directed against surface immunoglobulin. Stimulation with phorbol 12,13-dibutyrate (PDB) in combination with anti-IgM led to induction of the state of competence followed by progression to proliferation of the surface IgM-bearing cells. In contrast, sequential stimulation with PDB and anti-IgM in either order did not induce either competence or progression. Brief exposure to both stimuli for 30 min did not induce significant proliferation, but did induce the state of competence such that the cells progressed to DNA synthesis after incubation with PDB alone. Furthermore, a competence-related gene, c-fos, was induced in cells that did not become fully competent. Thus, induction of competence to proliferate required simultaneous delivery of two signals whereas actual progression to proliferation by competent cells was accomplished with only one signal.

Mechanisms of multidrug resistance in HL60 cells. Analysis of resistance associated membrane proteins and levels of mdr gene expression.

HL60 cells isolated for resistance to Adriamycin do not contain P-glycoprotein, as determined with immunological probes. These cells, however, are multidrug resistant and defective in the cellular accumulation of drug. In view of these findings, we have examined in greater detail certain properties of the HL60/Adr cells and have compared these properties to an HL60 drug-resistant isolate (HL60/Vinc) which contains high levels of P-glycoprotein. The results of these studies demonstrated that verapamil induces a major increase in cellular drug accumulation in both HL60/Adr and HL60/Vinc isolates. An 125I-labeled photoaffinity analog of verapamil labeled P-glycoprotein contained in membranes of HL60/Vinc cells. In contrast, this agent did not label any protein selectively associated with drug resistance in membranes of the HL60/Adr isolate. The photoactive dihydropyridine calcium channel blocker [3H]azidopine and [125I]NASV, a photoaffinity analog of vinblastine, labelled P-glycoprotein in membranes from HL60/Vinc cells, whereas in experiments with the HL60/Adr isolate there was no detectable labeling of a drug resistance associated membrane protein. Additional studies have been carried out to analyze membrane proteins of HL60/Adr cells labeled with the photoaffinity agent 8-azido-alpha-[32P]ATP (AzATP32). The results demonstrate that this agent labeled a resistance associated membrane protein of 190 kilodaltons (P190). P190 is essentially absent in membranes of drug-sensitive cells. Labeling of P190 with AzATP32 in membranes of resistant cells was blocked completely when incubations were carried out in the presence of excess unlabeled ATP. Additional studies were carried out to analyze mdr gene amplification and expression in sensitive and resistant cells. Experiments carried out with human 5',mdr1 (1.1 kb) and mdr3 (1.0 kb) cDNAs demonstrate that both of these sequences were highly amplified in the HL60/Vinc isolate. Only the mrd1 gene sequence however, was overexpressed. In contrast, there was no detectable amplification or overexpression of mdr1 or mdr3 sequences in HL60/Adr cells. The results of this study thus identify a new nucleotide binding protein which is overexpressed in membranes of HL60 cells isolated for resistance to Adriamycin. P190, which exhibits properties distinct from P-glycoprotein, possibly functions in the energy-dependent drug efflux system contained in the HL60/Adr resistant isolate.