A phase I trial evaluating the effects of plerixafor, G-CSF, and azacitidine for the treatment of myelodysplastic syndromes

Interactions between the bone marrow microenvironment and MDS tumor clones play a role in pathogenesis and response to treatment. We hypothesized G-CSF and plerixafor may enhance sensitivity to azacitidine in MDS. Twenty-eight patients with MDS were treated with plerixafor, G-CSF and azacitidine with a standard 3 + 3 design. Subjects received G-CSF 10 mcg/kg D1-D8, plerixafor D4-D8, and azacitidine 75 mg/m² D4-D8, but the trial was amended to reduce G-CSF dose to 5 mcg/kg for 5 days after 2 patients had significant leukocytosis. Plerixafor was dose escalated to 560 mcg/kg/day without dose limiting toxicity. Two complete responses and 6 marrow responses were seen for an overall response rate (ORR) of 36% in evaluable patients, and ORR of 53% in patients receiving the triplet. Evidence of mobilization correlated with a higher ORR, 60% vs. 17%. Plerixafor, G-CSF and azacitidine appears tolerable when given over 5 days and has encouraging response rates.KEY POINTSPlerixafor and G-CSF can be safely combined with azacitidine for 5 days in patients with MDS.The overall response rate of 53% for evaluable patients with this regimen is higher than expected and more responses were seen in patients with blast mobilization.

Abstract LB-162: Targeting CXCR4 for treatment of relapsed or refractory AML

In AML, the interaction of leukemic blasts with the bone marrow (BM) microenvironment is an important mediator of resistance to chemotherapy and disease relapse. The chemokine receptor, CXCR4, expressed on both normal HSCs and AML blasts, and serves as the principal regulator of stem cell homing and retention in the BM. We previously demonstrated in a murine model that blockade of CXCR4 by the small molecule inhibitor, plerixafor, mobilizes AML blasts into the peripheral circulation and sensitizes leukemic cells to chemotherapy (Nervi et al, Blood 2009). Furthermore, chemoprotection is mediated by bone marrow derived soluble factors which inhibits equilibrative nucleoside transporter 1 (ENT1) activity and cellular uptake of cytarabine (Nervi et al, PLoS One 2012). Based on these preclinical data, we have embarked on a series of studies combining plerixafor with chemotherapy for the treatment of AML. Our initial study combining plerixafor with chemotherapy demonstrated a CR rate of 46% in adults with relapsed or refractory AML (Uy et al, Blood 2012).

Methods. In this follow-up study, we sought to maximize CXCR4/CXC12 blockade by 1) adding G-CSF which downregulates CXCL12 production and 2) escalating the dose of plerixafor. G-CSF 10 mcg/kg was administered for 4 days prior to plerixafor and chemotherapy consisting of mitoxantrone 8 mg/m2, etoposide 100 mg/m2 and cytarabine 1000 mg/m2 IV x 5 days. Peripheral blood was collected at baseline, after G-CSF on day 3, and after both G-CSF and plerixafor on day 4 to study the effects on leukemic cell mobilization.

Results. In the Phase I, plerixafor was successfully escalated from 0.24 to 0.75 mg/kg/day. Peak mobilization of AML blasts occurred 4-6 hours post-plerixafor and remain elevated at 24 hours. We observed a unique pattern of CXCR4 expression using 2 monoclonal antibodies to CXCR4. The 12G5 mAb recognizes an epitope involving the first and second extracellular domains and inhibits plerixafor binding to CXCR4. In contrast, the 1D9 mAb binds to the N-terminus and is not affected by plerixafor. 12G5 binding decreased on CD45dimssclo AML blasts from baseline to 6 hours and an increase from 6 to 24 hours toward baseline. In contrast, we identified an increase in the binding of surface 1D9 after plerixafor occurring between pretreatment and 24 hours. Overall, these results indicate successful CXCR4 blockade by plerixafor in vivo with subsequent mobilization of AML blasts . The phase II is currently enrolling and will treat up to 46 patients. The completed phase II will allow us to determine the contribution of G-CSF and increased doses of plerixafor to both tumor mobilization and sensitivity to chemotherapy.

Citation Format: Geoffrey L. Uy, Michael P. Rettig, Kyle McFarland, John F. DiPersio. Targeting CXCR4 for treatment of relapsed or refractory AML. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-162. doi:10.1158/1538-7445.AM2013-LB-162

First Report of the Peach Brown Rot Fungus Monilinia fructicola Resistant to Demethylation Inhibitor Fungicides in New Jersey

Reduced sensitivity and resistance of Monilinia fructicola to demethylation inhibitors (DMIs; fungicide group 3) have been previously found in stone fruit orchards in Georgia, South Carolina, Ohio, and New York (2). Resistance development is a major concern because of the importance of DMIs for brown rot management. Eleven single-spore isolates, originally collected during 2006 from separate commercial peach (Prunus persica) orchards in southern New Jersey, were removed from cold storage (5°C) in early 2008 and examined in vitro for resistance to the DMI propiconazole (Orbit 3.6EC; Syngenta Crop Protection, Inc., Greensboro, NC). After 19 months at 5°C, isolate 7 was inhibited 53.4% in growth on potato dextrose agar (PDA) amended at the discretionary dose of 0.3 μg/ml propiconazole; inhibition of the remaining isolates ranged from 81.4 to 100%. Inhibition values were based on two replications of eight colonies per isolate performed after incubation at 25°C for 4 days. Because of the previously reported relationship between duration of cold storage and propiconazole sensitivity, isolate 7 was tentatively deemed resistant (1). To confirm the in vitro results, isolates were grown at 25°C for 7 days on cellophane over PDA. Genomic DNA was isolated from mycelium with the DNeasy Plant Mini Kit (Qiagen, Inc., Valencia, CA). PCR with primers INS65-F and INS65-R was conducted on a GeneAmp thermal cycler (Applied Biosystems, Inc., Foster City, CA) as described previously to amplify a 65-bp region named 'Mona' associated with DMI resistance (2). PCR products were separated via electrophoresis on 0.8% agarose gel. The primers amplified a 376-bp fragment from isolate 7 and a 311-bp fragment from all other isolates, thus indicating the presence of Mona in isolate 7. Restriction fragment length polymorphism analysis using the BsrBI enzyme, specific to a single restriction site within Mona, was conducted on the amplified fragments from all isolates. Electrophoresis results showed digestion of the 376-bp fragment from isolate 7 into 140-bp and 236-bp fragments, thereby confirming the presence of Mona; none of the 311-bp fragments from the remaining isolates were cut by BsrBI. Although economic loss from brown rot has not been reported in New Jersey, these results show that propiconazole-resistant strains have been detected since 2006 and it is most likely that resistant strains of the pathogen are still present in commercial peach orchards. To combat this risk, current brown rot control recommendations are incorporating quinone outside inhibitors (QoIs; fungicide group 11) and carboxamides (fungicide group 7) into control programs as a resistance management strategy. More extensive sampling is planned to ascertain the prevalence and location of resistant strains. References: (1) K. D. Cox et al. Phytopathology 97:448, 2007. (2) C.-X. Luo et al. Plant Dis. 92:1099, 2008.

Influence of factor IX on overall plasma coagulability and fibrinolytic potential as measured by global assay: monitoring in haemophilia B

We sought to determine the influence of factor IX (FIX) deficiency upon overall coagulative and fibrinolytic capacities in plasma using the clot formation and lysis (CloFAL) assay, and to investigate the role of this global assay as an adjunctive monitoring tool in haemophilia B. CloFAL assay parameters were measured in vitro in platelet-poor plasma in relation to FIX activity and antigen (FIX:Ag), and were determined ex vivo among FIX-deficient patients (n = 41) in comparison to healthy individuals (n = 48). Supplementation of FIX-deficient plasma with FIX in vitro demonstrated a non-linear concentration dependence of FIX upon overall plasma coagulability. Ex vivo, coagulability was significantly decreased in FIX-deficient vs. healthy subjects among adults [median coagulation index (CI): 4% vs. 104% respectively; P < 0.001] and children (median CI: 9% vs. 63%; P < 0.001). Fibrinolytic capacity was increased in adult FIX-deficient vs. healthy subjects (median fibrinolytic index: 216% vs. 125%, respectively, P < 0.001), and was supported by a trend in shortened euglobulin lysis time (ELT). Severe haemophilia B patients showed heterogeneity in aberrant CloFAL assay waveforms, influenced partly by FIX:Ag levels. Patients with relatively preserved FIX:Ag (i.e. dysfunctional FIX) exhibited a shorter time to maximal amplitude in clot formation than those with type I deficiency. During patient treatment monitoring, markedly hypocoagulable CloFAL assay waveforms normalized following 100% correction with infused FIX. The CloFAL global assay detects FIX deficiency, demonstrates differences in coagulability between dysfunctional FIX and type I deficiency, and appears useful as an adjunctive test to routine FIX measurement in monitoring haemophilia B treatment.

Influence of factor VIII on overall coagulability and fibrinolytic potential of haemophilic plasma as measured by global assay: monitoring in haemophilia A

The objectives of the present study were to evaluate the analytical sensitivity of the recently developed Clot Formation and Lysis (CloFAL) global assay for factor VIII (FVIII) deficiency, both in vitro and ex vivo, to determine whether this global assay is influenced by FVIII inhibitors, and to investigate the coagulative response to FVIII replacement in haemophilia A patients using the CloFAL assay in comparison with FVIII activity. Among adults and children alike, the CloFAL assay coagulation index (CI) was significantly decreased in FVIII-deficient vs. healthy subjects (adults median CI: 2% vs. 94% respectively; children median CI: 3% vs. 63%; P < 0.001 for each), and correlated significantly with activated partial thromboplastin time-based FVIII activity across all individuals (r = 0.78; P < 0.001). The CloFAL assay was analytically sensitive to deficient FVIII activity and also influenced by the presence of von Willebrand factor. Severe haemophilia A patients without inhibitory antibodies to FVIII showed considerable heterogeneity in CloFAL assay waveforms, despite a uniformly diminished CI of 0-1%. During FVIII infusion half-life studies in patients with severe haemophilia A, the CloFAL assay demonstrated a marked rise in coagulability 30 min following infusion, with progressive decrease in coagulability towards baseline over the ensuing 48-h period. In each case, the profile of coagulative response to FVIII infusion as determined by CloFAL assay CI differed qualitatively from that measured by FVIII activity. These findings indicate that the CloFAL assay may be useful as an adjunctive test to FVIII activity measurements in the therapeutic monitoring of haemophilia A.

Lateralization of speech production using verbal/manual dual tasks: meta-analysis of sex differences and practice effects

The present paper reviews the findings of 30 years of verbal/manual dual task studies, the method most commonly used to assess lateralization of speech production in non-clinical samples. Meta-analysis of 64 results revealed that both the type of manual task used and the nature of practice that is given influence the size of the laterality effect. A meta-analysis of 36 results examining the effect size of sex differences in estimates of lateralization of speech production indicated that males appear to show slightly larger laterality effects than females.

Repeated cocaine administration alters the electrophysiological properties of prefrontal cortical neurons

Recently it has become clear that some of the symptoms of addiction such as relapse to drug-taking behavior arise, in part, from a dysfunction in cognitive and emotional processing. This realization has promoted investigations into the physiology and pathophysiology of forebrain circuits that are both innervated by dopamine and play an important role in cognitive processing, including the prefrontal cortex. In order to study long-term neuroadaptations occurring in the prefrontal cortex of the rat as a consequence of psychostimulant administration, cocaine was repeatedly administered in either a contingent or a non-contingent manner. At least 2 weeks following the last cocaine injection, in vivo intracellular recordings were made from neurons located in the deep layers of the prefrontal cortex. Repeated cocaine administration abolished the presence of membrane bistability normally present in neurons located in the limbic prefrontal cortex. These results indicate that repeated exposure to cocaine produces enduring changes in the basal activity of neurons in the prefrontal cortex that may contribute to previously identify cognitive and emotional dysfunctions in cocaine addicts.

The circuitry mediating cocaine-induced reinstatement of drug-seeking behavior

The role of limbic-striato-pallidal circuitry in cocaine-induced reinstatement was evaluated. The transient inhibition of brain nuclei associated with motor systems [including the ventral tegmental area (VTA), dorsal prefrontal cortex (dPFC), core of the nucleus accumbens (NAcore), and ventral pallidum (VP)] prevented cocaine-induced reinstatement. However, only the VP proved to be necessary for food reinstatement, suggesting that the identified circuit is specific to drug-related reinstatement. Supporting the possibility that the VTA-dPFC-NAcore-VP is a series circuit mediating reinstatement, simultaneous unilateral microinjection of GABA agonists into the dPFC in one hemisphere and into the VP in the contralateral hemisphere abolished cocaine reinstatement. Although dopamine projections from the VTA innervate all three forebrain nuclei, the blockade of dopamine receptors only in the dPFC antagonized cocaine-induced reinstatement. Furthermore, DA administration into the dPFC was sufficient to elicit a reinstatement in drug-related responding. These data demonstrate that dopamine release in the dPFC initiates a dPFC-NAcore-VP series circuit that mediates cocaine-induced drug-seeking behavior.

Post-Traumatic amnesia: consistency-of-recovery and duration-to-recovery following traumatic brain impairment

The aim of this research was to examine the nature and order of recovery of orientation and memory functioning during Post-Traumatic Amnesia (PTA) in relation to injury severity and PTA duration. The Westmead PTA Scale was used across consecutive testing days to assess the recovery of orientation and memory during PTA in 113 patients. Two new indices were examined: a Consistency-of-Recovery and a Duration-to-Recovery index. A predictable order of recovery was observed during PTA: orientation-to-person recovered sooner and more consistently than the following cluster; orientation-to-time, orientation-to-place, and the ability to remember a face and name. However, the type of memory functioning required for the recall face and name task recovered more consistently than that required for memorizing three pictures. An important overall finding was that the "order-of-recovery" of orientation and memory functioning was dependent upon both the elapsed days since injury, and the consistency of recovery. The newly developed indices were shown to be a valuable means of accounting for differences between groups in the elapsed days to recovery of orientation and memory. These indices also clearly increase the clinical utility of the Westmead PTA Scale and supply an objective means of charting (and potentially predicting) patients' recovery on the different components of orientation and memory throughout their period of hospitalization.

Effect of sequential transdermal progesterone cream on endometrium, bleeding pattern, and plasma progesterone and salivary progesterone levels in postmenopausal women

BACKGROUND

Transdermal progesterone is being used in some countries as a purported treatment for menopausal symptoms, either alone or prescribed in conjunction with estrogen, but little information exists regarding the biological activity and effectiveness of this method of delivery of progesterone in protecting the endometrium from excess proliferation. This study was designed to evaluate the use of sequential transdermal progesterone. End-points evaluated included endometrial cellular response and bleeding pattern as well as plasma hormone levels and salivary progesterone estimations.

METHOD

Twenty-seven postmenopausal women were treated with continuous transdermal estrogen (28-day cycle) and a cream containing 16, 32 or 64 mg of progesterone in each 4-cm extrusion from a tube of Pro-Feme administered daily in a sequential (days 15-28 of cycle) regimen. Blood and endometrial samples were analyzed for progesterone response prior to therapy, after the first 14 days of unopposed transdermal estrogen and following 14 days of transdermal progesterone. Saliva samples were taken during the last 14 days of the 84-day study, when the final progesterone cream therapy was being applied.

RESULTS

Hormone assay indicated that physiological levels of estradiol were achieved, but progesterone levels were insufficient to induce any detectable change in the endometrium. Only one patient experienced bleeding during the study period. Levels of salivary progesterone were so variable as to be considered completely unreliable in determining the potential influence on biological activity.

INTERPRETATION

Pro-Feme transdermal progesterone administered in a 16-, 32- or 64-mg daily dose for 14 days in a sequential regimen does not appear to be effective in inducing a secretory change in a proliferative endometrium. Salivary progesterone levels were not of value in managing the therapy of postmenopausal women.

Search for a W' boson via the decay mode W'-->munumu in 1.8 TeV pp collisions

We report the results of a search for a W' boson produced in pp collisions at a center-of-mass energy of 1.8 TeV using a 107 pb-1 data sample recorded by the Collider Detector at Fermilab. We consider the decay channel W'-->&munumu and search for anomalous production of high transverse mass munumu lepton pairs. We observe no excess of events above background and set limits on the rate of W' boson production and decay relative to standard model W boson production and decay using a fit of the transverse mass distribution observed. If we assume standard model strength couplings of the W' boson to quark and lepton pairs, we exclude a W' boson with invariant mass less than 660 GeV/c2 at 95% confidence level.

Cisplatin-based therapy: a neurological and neuropsychological review

The present paper reviews research in the area of the broad-spectrum chemotherapeutic agent cisplatin (cis-diamminedichloro-platinum II) and examines the implications for clinical neuropsychology arising from the neurological disruption associated with cisplatin-based therapy. The paper begins with a brief review of cisplatin treatment in terms other than survival alone, and examines the side-effects and the potential central nervous system (CNS) dysfunction in terms of neurological symptoms and concomitant implications for neuropsychology. Two main implications for clinical neuropsychology arising from cisplatin therapy are identified. First, cisplatin therapy impacts upon the psychological well-being of the patient, particularly during and in the months following treatment. It is suggested that during this time, a primary role for neuropsychology is to focus upon the monitoring and the active enhancement of the patient's social, psychological and spiritual resources. Second, with regard to neurocognitive changes, the review suggests that (1) neurocognitive assessment may not yield stable results within 8 months following treatment and (2) while perceptual, memory, attentional and executive dysfunction may be predicted following cisplatin treatment, little systematic research has been carried out to investigate such a possibility. Future research might profitably address this issue and also specifically examine the effects of low dosage cisplatin-based therapy and the effects of recently developed neuroprotective agents. Finally, there is some evidence to suggest that women may be more susceptible to neurotoxicity during cisplatin therapy, but no gender-related cognitive effects are reported in the cisplatin literature. Future research could usefully investigate gender differences in association with cisplatin chemotherapy.

Micronised transdermal progesterone and endometrial response

Sequential transdermal progesterone administered with continuous transdermal oestrogen was insufficient to increase circulating blood progesterone concentrations or induce a secretory response in proliferating endometrium.

Haloperidol does not attenuate conditioned place preferences or locomotor activation produced by food- or heroin-predictive discriminative cues

The present study examined whether a discriminative cue previously predictive of food or heroin reinforcement could activate and direct behavior in an environment that had never been paired with primary reinforcement. Olfactory cues, predicting the availability (S+) or unavailability (S-) of either heroin (0.1 mg/kg i.v.) or food (45 mg Noyes food pellets) reinforcement in the goal box of a straight-arm runway, were later tested in a separate environment for their ability to elicit locomotion (activate behavior) or induce a conditioned place preference (direct behavior). Presentation of the S+, but not the S-, resulted in a reliable increase in spontaneous locomotor activity that was not blocked by pretreatment with the dopamine receptor antagonist, haloperidol. Similarly, subjects displayed a preference for a novel location in which the S+, but not the S-, was placed. This preference was also unaltered by pretreatment with haloperidol. These data suggest that discriminative cues can profoundly affect behavior, even in environments that have themselves never been associated with primary reinforcement. Additionally, the conditioned motivational quality of these cues is unaltered by treatment with the same dopamine receptor antagonist shown in previous work to attenuate the primary reinforcing properties of heroin and food.

Naloxone blocks reinforcement but not motivation in an operant runway model of heroin-seeking behavior

The present study examined the effects of opiate receptor antagonism on both the motivation to seek heroin and the reinforcing consequences of heroin administration. Subjects were trained to discriminate between olfactory cues predicting either the delivery of intravenous heroin reinforcement (S+) or saline (S-). Subjects were then tested in the presence of the opiate receptor antagonist, naloxone (0.5, 1.0, or 3.0 mg/kg intraperitoneally). Naloxone had no effect on either S+ or S- trials. However, 24 hr later on the first posttreatment trial, subjects that had received heroin in the presence of naloxone (on the previous trial) now traversed the alley more slowly when presented with the S+. These data suggest that although the motivation to seek heroin was not disrupted by naloxone, the reinforcing consequences of heroin administration were.

Haloperidol does not affect motivational processes in an operant runway model of food-seeking behavior

The present experiment examined the effects of dopamine receptor antagonism on subjects' motivation to seek food. Rats were trained to discriminate between 2 olfactory cues predicting either the presence (S+) or absence (S-) of food reinforcement in the goal box of a straight-arm runway. Rats learned to traverse the alley quickly when presented with the S+ and much more slowly when presented with the S-. Haloperidol pretreatment was unable to alter this pattern of behavior (i.e., rats still ran quickly when presented with the scent that predicted food availability). Thus, it seems that the same dopamine antagonist treatments that have been shown to disrupt food reinforcement do not prevent the food-seeking behavior produced by presentation of food-predictive cues.

Haloperidol does not affect motivational processes in an operant runway model of food-seeking behavior

The present experiment examined the effects of dopamine receptor antagonism on subjects' motivation to seek food. Rats were trained to discriminate between 2 olfactory cues predicting either the presence (S+) or absence (S-) of food reinforcement in the goal box of a straight-arm runway. Rats learned to traverse the alley quickly when presented with the S+ and much more slowly when presented with the S-. Haloperidol pretreatment was unable to alter this pattern of behavior (i.e., rats still ran quickly when presented with the scent that predicted food availability). Thus, it seems that the same dopamine antagonist treatments that have been shown to disrupt food reinforcement do not prevent the food-seeking behavior produced by presentation of food-predictive cues.

Anatomy and ultrastructure of the sporophyte of Takakia ceratophylla (Bryophyta)

In this study, morphogenesis and structure of the sporophyte of Takakia ceratophylla are characterized beginning with the late embryo and culminating in the fully dehisced capsule. Information is presented on the development, ultrastructure, and anatomy of the three organographic regions of the sporophyte, namely capsule, seta, and foot. Diagnostic features that identify Takakia as a moss include the gradual elongation of seta, persistence of an apical calyptra, expansion of the capsule after cessation of seta elongation, existence of a columella, monoplastidic meiosis, spore ultrastructure (including a perine layer deposited late in spore wall (development), and the structure of the foot. Commonalities with the capsule of the Andreaeopsida include sporogenous tissue that overarchs a central columella, absence of stomata, and lack of a peristome and operculum. Peculiarities of the genus are seen in the internal structure of the capsule, the disintegration of the columella with spore maturation, and the dehiscence of the capsule along a single, spiralled, longitudinal suture line. Passive spore dispersal through longitudinal splitting of the capsule occurs in andreaeopsid mosses, liverworts, hornworts, and seedless vascular plants. The precise mechanism of dehiscence along a spiralled suture is unparalleled in extant archegoniates but finds counterparts in ancestral land plants such as the pteridophyte Tortilicaulis.

Reinstatement of drug-seeking behavior produced by heroin-predictive environmental stimuli

The current study examined whether stimuli predictive of heroin availability were capable of inducing a relapse of drug-seeking behavior in an operant runway task. Olfactory stimuli (orange and almond food extract) served as discriminative cues about the availability (S+) or unavailability (S-) of heroin reinforcement (a single 0.1 mg/kg IV infusion) in the goal box of a straight arm runway. Following discrimination training, the running response was extinguished in the absence of the olfactory cues. On a single trial, the discriminative stimuli were then tested for their ability to reinstate running behavior prior to presentation of the heroin reinforcer. Subjects presented with the S+ on test day took significantly less time to traverse the alley than they did on the final day of extinction, while those subjects presented with the S- on test day continued to run slowly. These results demonstrate, in an animal model of drug self-administration, that environmental discriminative cues can produce a relapse in drug seeking behavior following a period of abstinence. The response-reinstating properties of the S+ odor were unaltered by pretreatment with any of three doses of haloperidol (0.0, 0.15 or 0.3 mg/kg IP), suggesting that the motivating properties of heroin-predictive stimuli or cues remain intact during dopamine receptor antagonism.

Mild head injury and speed of information processing: a prospective study of professional rugby league players

The sensitivity of several short tests of speed of information processing to the effects of mild head injury in rugby league football was investigated. The measures used were the Symbol Digit Modalities Test, the Digit Symbol Substitution Test, and the Speed of Comprehension Test. Two studies were conducted, the first to examine the effect of practice, the second to determine sensitivity to cognitive impairment immediately following injury. The first study established alternate form equivalence and demonstrated that performance on the Speed of Comprehension and Digit Symbol Substitution tests improved with practice, whereas the Symbol Digit Modalities test remained stable. A second study of 10 players who subsequently sustained mild head injuries showed that measures of speed of information processing were sensitive to impairment in the postacute phase, whereas an untimed task of word recognition (Spot-the-Word) was not. Speed of Comprehension was more sensitive to postinjury impairment than either the Digit Symbol Substitution or Symbol Digit Modalities tests. A repeated baseline assessment before injury using the higher score to reflect a player's potential, allowed measurement of impaired performance on sensitive tests.

Nitrous-oxide use. II. Risks, compliance, and exposure levels among Nebraska dentists and dental assistants

This study measured nitrous oxide (N2O) exposure levels of 70 dentists and their dental assistants, and related these results to minutes of N2O use, compliance with N2O use guidelines, and risk of exposure. Dentists and dental assistants averaged, respectively, 97 and 59 parts per million (ppm) in N2O exposure, much higher than the recommended 25 to 50 ppm. Estimated peaks of exposure averaged 1,415 and 986 respectively for the two groups. Dentists exposure levels were significantly higher than those of dental assistants in both measures. Correlations revealed a significant link between compliance and estimated maximum exposure, and between minutes of use and 40-hour exposure readings. The variables most predictive of 40-hour N2O exposure were: minutes of use, frequency of use, number of operatories equipped, education of staff members on N2O health risks and exposure control, and operation of scavenging systems with the recommended liters/minute. This study established a feasible methodology for long-term, field-based epidemiological studies on N2O exposure, and identified some key variables related to 40-hour exposures and estimated maximum exposure.

Nitrous-oxide use. I. Risk of potential exposure and compliance among Nebraska dentists and dental assistants

Patterns of nitrous-oxide (N,O) use among Nebraska dentists and dental assistants are reported. More than 800 respondents answered questions relating to risk of N,O exposure and compliance with N,O standards in the dental office: 73 percent of these dental practices using N,O have a state-registration permit. Dentists and dental assistants (from registered and unregistered practices) reported risk of exposure differently. Important compliance issues emerged (the average compliance rate was 9 on a scale of 17). Most N,O users have scavenging systems, but they are not properly operated. Few dental practices test for leaks or conduct N,O-monitoring tests. By complying with the recommendations for N,O administration, dental-care workers can minimize their risk of exposure.

Addition of anticholinergic solution prolongs bronchodilator effect of beta 2 agonists in patients with chronic obstructive pulmonary disease

A randomized, double-blind placebo-controlled clinical trial was designed to assess the safety, efficacy, and duration of the bronchodilation resulting from the addition of 500 micrograms of ipratropium bromide (Atrovent; Boehringer Ingelheim, CT) inhalation solution to standard small volume nebulizer treatments with 2.5 mg albuterol inhalation solution. A total of 195 patients (63% men, average age 64 years) with > 10 pack-year smoking histories and stable, moderate-to- severe chronic obstructive pulmonary disease (COPD; forced expiratory volume in 1 second [FEV1] 1.02 liter, 38.8% predicted) from eight university-affiliated chest clinics in seven U.S. cities were enrolled into the study. Asthma, rhinitis, and eosinophilia were exclusions, as was daily use of > 10 mg of prednisone (or 20 mg on alternate days). There was a 2-week stabilization period during which the patients were instructed in the use of the small volume nebulizers, which they used three times daily with albuterol alone. They were asked to keep daily logs of peak flow rates, pulmonary symptoms, and additional medication usage. On their test day 1 the subjects came to the pulmonary function laboratory having been off theophylline for 24 hours and beta 2-agonists for 12 hours and performed a baseline spirometry. They then received their morning small volume nebulizer treatment of albuterol to which was added either 500 micrograms if ipratropium bromide or a saline placebo. Spirometry was repeated at 15, 30, and 60 minutes, and then hourly for 8 hours. Subjects then took home a 2-week supply of albuterol and test drug for thrice daily use in their small volume nebulizer. They were evaluated for pulmonary symptoms and adverse effects every 14 days. The 8-hour spirometry was repeated on test day 43 and finally on test day 85. Primary data evaluated were the peak increase in FEV1 and the area between the FEV1 baseline value and the 8-hour FEV1 curve. Similar calculations were made for forced vital capacity (FVC) and 25-75% forced expiratory flow (FEF25-75%). On test day 1 the peak increase in FEV1 for the ipratropium bromide + albuterol subjects was 26% greater than those on placebo + albuterol (p < 0.003). The area under the 8-hour FEV1 curve was 64% greater in those given ipratropium bromide on test day 1 (p < 0.0002). Similar increases were seen in FVC and FEF25-75%. The peak improvements in FEV1 and FVC with the addition of ipratropium bromide to albuterol were maintained on test days 43 and 85. Considering the safety and efficacy profiles of this combination, the data would suggest that ipratropium bromide inhalation solution should be considered first-line therapy for those patients with COPD requiring small volume nebulizer treatments.

Haloperidol differentially affects reinforcement and motivational processes in rats running an alley for intravenous heroin

The role of drug-paired environmental stimuli in opiate self-administration was investigated by exposing animals to discrete cues that were predictive of the availability or unavailability of heroin reinforcement. Rats were trained to traverse a straight arm runway for a reinforcement consisting of a single 0.1 mg/kg intravenous infusion of heroin delivered upon entrance to the goal box. On each trial, one of two discriminative olfactory stimuli (orange and almond) was used: one which signaled the availability of heroin in the goal box (S+), and one which signaled its absence (S-). The effect of dopamine (DA) receptor antagonism on reinforcement and motivational processes was investigated by pretreating subjects with 0.0, 0.15 or 0.30 mg/kg of the DA receptor antagonist drug, haloperidol. Haloperidol had no effect on operant runway performance (i.e. goal time) in any condition. However, 24 h later, on the first post-treatment trial, those haloperidol animals that received heroin in the goal box on the previous trial (i.e. the S+ condition) ran reliably more slowly than subjects that received vehicle on the previous S+ trial. These results suggest that haloperidol does not affect the motivational properties of stimuli which predict the availability of heroin, while it does diminish the reinforcing effects of actually receiving heroin.

Effects of closed-head injury on attentional processes: generality of Sternberg's additive factor method

The present study examined the generality of Shum, McFarland, Bain, and Humphreys' (1990) findings that closed-head injury (CHI) selectively impairs different processes of attention (operationalized in terms of stages of information processing) depending on the severity of, and the time since, injury. The procedure of Shum et al. was based on Sternberg's additive factor method (AFM), with the mode of information processing involved being a physical-directional matching of visual stimuli. The present study followed a similar procedure except that a name-matching task was used. This task was administered to 16 first-year psychology students and two groups of CHI patients (viz., severe short-term (SS) and severe long-term (SL)) with matched control groups. The results obtained replicated the study by Shum in that the SS group was found to be impaired on the identification and response-selection stages of information processing whereas the SL group was found to be impaired only on the response-selection stage. The present study confirms that the AFM is not limited to one specific mode of information process and strengthens the validity of the conclusions made by Shum et al. regarding the effects of CHI on attention.

Assessment of attention: relationship between psychological testing and information processing approaches

Examined the relationship between the psychological testing and information processing approaches in assessing attention. Eighty-seven subjects (57 females, 30 males) undertook eight psychological tests of attention and a visual-spatial reaction-time task. Using the cognitive-correlate method (Posner & McLeod, 1982), it was found that three components of attention (viz., visual-motor scanning, sustained selective processing, and visual/auditory spanning) derived from the psychological tests could be significantly predicted by specific, yet different, combinations of six indices of information processing (mean reaction time (RT), mean movement time (MT), feature extraction, identification, response selection, and motor adjustment): (a) mean RT and mean MT were found to be the most important indices for predicting performance on visual-motor scanning; (b) the motor-adjustment stage was found to be the most important index for predicting performance on sustained selective processing; (c) the response-selection stage was found to be the most important index for predicting performance on visual/auditory spanning. These relationships are important for supporting the construct-related validity of the psychological tests of attention and for extending the generality and applicability of the RT task.

Hemispheric differences in image generation and use in the haptic modality

Forty adults and 40 children, all right-handed, were presented with either of two series of six nonsense shapes to palpate: Those who were divided into sections by grid lines and thus provided categorical information or those who provided a whole shape and coordinate information that could be processed globally. Subjects were given an Input condition where they formed a mental representation of the shape while palpating the unseen tactual stimulus with either hand, followed by an Evaluation condition in which they attempted to solve the task by generating and using the previously stored image. Evaluation response times showed that the left hemisphere was significantly faster at generating images from categorically stored information. Neither hemisphere had an advantage when generating an image from globally stored information.

Peritoneal dialysis in the neonatal period: outcome data

Scant information exists on the prognosis of infants with renal failure who receive peritoneal dialysis in the first month of life. We reviewed the outcome of 23 such patients 1 year after the onset of renal failure. Diagnoses included acute tubular necrosis (11 infants), renal dysplasia (5), obstructive uropathy (4), polycystic kidney disease (1), renal vein thrombosis (1), and renal artery thrombosis (1). Seven of the eleven patients with acute tubular necrosis had had cardiac surgery. At 1 year, eight (35%) of the patients had died, six (26%) had a full recovery, seven (30%) were receiving long-term dialysis awaiting a transplant, and two (9%) had chronic renal failure. Effective dialysis, characterized by the reversal of metabolic disturbances or attainment of fluid balance, was accomplished in all patients. The mean duration of dialysis was 4.5 months (range, 0.1 to 12 months). The most common complications of dialysis were peritonitis and catheter exit site infection. Despite the provision of supplemental calories via nasogastric tube, the majority of patients receiving long-term dialysis showed impaired growth and mild developmental abnormalities. Peritoneal dialysis is an effective means of renal replacement therapy in the neonatal period; however, the morbidity and mortality rate for this population remains high.

Attentional deficits in head-injured children: an information processing analysis

Attentional problems of closed head-injured (CHI) children were examined using an information processing (IP) approach. Based on Sternberg's (1969) additive factor method (AFM), the study examined attentional processes in terms of four stages and their corresponding task variables. A visual-spatial choice reaction-time task was undertaken with two groups of CHI children (severe and mild to moderate) and corresponding matched control groups. Results indicated that for this task both the CHI and the normal children exhibited a similar mode of linear, sequential information processing. It was found that the severe group was impaired not only in terms of slowed motor execution but also in terms of response selection. This group showed no impairment on the feature extraction, stimulus identification, and motor adjustment stages of processing. No evidence of impairment on any of the stages was found for the mild group. The utility of the AFM and implications of these findings are discussed with reference to CHI children and to neuropsychological assessment and rehabilitation.

A simple dual-task study of laterality, sex-differences and handedness

Nine-hundred and eighty-one right-handed and 55 left-handed subjects were required to tap with a pen for 10 secs between targets 6 cm apart whilst either saying nothing, reciting a tongue-twister or saying la-la. The numbers of dots produced in 10 secs in each condition were analysed. The right-handed group demonstrated the usually found degradation in their right-hand performance whilst reciting the meaningful words, but showed a lesser effect when saying la-la. Their left-handed performance was essentially unaffected. Absolutely no evidence for the presence of a sex difference in lateralization of language was found. The much smaller sample of left-handed subjects presented a complex picture of no significant effects, whether they were the sole left-handers in their family, or had other left-handed close relations.

Effects of closed-head injury on attentional processes: an information-processing stage analysis

The present study, based on Sternberg's (1969) additive-factor method, examined attentional processes in terms of four information-processing stages (feature extraction, identification, response selection, and motor adjustment). Four task variables were used to operationally define the stages (signal quality, signal similarity, signal-response compatibility, and foreperiod uncertainty). In two studies, a visuo-spatial reaction-time task was undertaken by a group of university subjects (Experiment 1) and by three groups of closed-head-injured patients (severe short-term, severe long-term, and mild short-term) and their corresponding matched controls (Experiment 2). The results indicated that both patients and normals exhibited a similar mode of linear information processing. In addition, it was found that the severe short-term group was impaired on the response-selection stage and response selection stage; the severe long-term group was impaired only on the response-selection; and no evidence of impairment was found for the mild short-term patients. The implications of these findings with reference to the study of attentional processes in closed-head injured patients and to neuropsychological assessment and rehabilitation are discussed.

Tactile perceptual asymmetry: the influence of motor activity and imagery instructions

The purpose of this study was to examine the degree to which changes in muscular activity modify tactile perceptual asymmetries. In two experiments subjects were presented with a series of pairs of random shapes to the fingers of each hand. Their task was to detect the occurrence of a previously learnt target shape. Pressing on to the shape was the only movement allowed and other types of motor activity, particularly tracing movements, were not permitted. Across experimental conditions subjects were required to change the pressure and hence muscular effort used to press upon the shape. A left-hand advantage was found across all experimental conditions and its size did not change when subjects were required to press either firmly or lightly upon the shapes. This result was also found when subjects were required to apply uneven pressure between the hands. One-half of the subjects also performed the experimental conditions following instructions to use imagery. This produced an enhancement of right-hand performance on the task with a loss of the left-hand advantage. The results suggest that observed tactile perceptual asymmetries, while unaffected by changes in muscular effort, are easily overridden by higher-order cognitive and motor processes.

A dual-task study of sex differences in language reception and production

The notion that females may be less lateralized than males for language reception was tested using a variant of the dual-task technique with 20 normal right-handed subjects. A unimanual tapping task was paired with one language reception task, and two language production tasks (one purely cognitive and the other requiring both cognitive and vocal involvement). Performance was impaired in all treatment conditions, regardless of hand used. Most impairment was, however, found in right-hand performance during the vocal condition. No sex differences were found.

Lateralised dual-task performance: the effect of muscular-repositioning

In two experiments subjects performed tapping tasks requiring different degree of muscular repositioning while concurrently performing a speech task. In all concurrent speech conditions right-hand performance was disrupted more than left-hand performance, but the degree of this differential disruption did not alter as a function of the muscular repositioning requirements of the dual-tasks. It was concluded that rapid muscular repositioning does not appear to be the source of lateralised interference effects observed in concurrent task studies. However, it may be argued that some minimum level of repositioning is required, particularly if the differential effect reflects a lateralisation of "kind" rather than of "degree". This needs further research. One relevant factor proposed here which may alter the degree of lateralised effects is the degree of muscular effort required to perform each of the dual-tasks.

Lateralized dual-task performance: the effects of spatial and muscular repositioning

In three experiments subjects were required to perform different manual tapping tasks using either the left or right hand while concurrently performing a speech task. The major independent variables examined were muscular effort and the spatial and muscular repositioning components of the tapping tasks. In all speech conditions right hand performance was disrupted more than left hand performance. The degree of this lateralized disruption did not alter as a function of variation in either muscular effort or the repositioning requirements of the manual task. However, muscular repositioning activity, unlike other components of the motor task, was affected bilaterally by the addition of the speech task. Overall the results suggest that the dual-task procedure can be used to assess two types of "lateralized" interference effects; one relating to right hand performance, the other to left hemisphere performance.

Syndrome analysis in clinical neuropsychology

The application of syndrome analysis in clinical practice has tended to rely on rather qualitative diagnoses by the neuropsychologist. The present paper proposes the use of a decision theory method which enables a systematic approach to be made to neuropsychological diagnosis. It is argued that the proposed method not only aids diagnostic decision making but also enables probabilities to be associated with particular prognostic statements. In this way the method is useful for guiding testing procedures and optimizing treatment programmes for particular patients.

Speech lateralization assessed by concurrent task performance

A sequential button pressing task using either the left or the right hand while concurrently performing a speech task was investigated. Subjects with left-hemisphere speech representation, determined by a dichotic monitoring task showed a lateralized practice effect: left-hand performance improved with practice during the speech task, but right-handed performance did not. Subjects with right-hemisphere speech representation showed disruption of either hand with concurrent speech, and no lateralized practice effect. The results from this study suggest the mechanisms mediating speech perception and speech production may not always be concordantly lateralized. A discriminant analysis of the data showed that 93% of subjects could be correctly classified according to side of representation of speech perception given the performance measures on the concurrent tasks.