Predicting resistance management skill from psychotherapy experience, intellectual humility and emotion regulation

OBJECTIVE

Resistance management in psychotherapy remains a foundational skill that is associated with positive client outcomes (Westra, H. A., & Norouzian, N. (2018). Using motivational interviewing to manage process markers of ambivalence and resistance in cognitive behavioral therapy. Cognitive Therapy and Research, 42(2), 193-203). However, little is known about which therapist characteristics contribute to successful management of resistance. Research has suggested that psychotherapy performance does not improve with experience (Goldberg, S. B., Rousmaniere, T., Miller, S. D., Whipple, J., Nielsen, S. L., Hoyt, W. T., & Wampold, B. E. (2016). Do psychotherapists improve with time and experience? A longitudinal analysis of outcomes in a clinical setting. Journal of Counseling Psychology, 63(1), 1-11), that psychotherapists lack humility (Macdonald, J., & Mellor-Clark, J. (2015). Correcting psychotherapists' blindsidedness: Formal feedback as a means of overcoming the natural limitations of therapists. Clinical Psychology & Psychotherapy, 22(3), 249-257), and that difficult therapeutic moments may dysregulate therapist emotions (Muran, J. C., & Eubanks, C. F. (2020). Therapist performance under pressure: Negotiating emotion, difference, and rupture. American Psychological Association). This study aimed to 1) identify whether psychotherapy experience (i.e., training versus no training and number of years of psychotherapy experience) was associated with resistance management skill, and 2) identify whether humility and difficulties regulating emotions among trained individuals were each associated with resistance management.

METHOD

A sample of 76 trained and 98 untrained participants were recruited for the present study. All participants completed the Comprehensive Intellectual Humility Scale (CIHS, Krumrei-Mancuso, E. J., & Rouse, S. V. (2016). The development and validation of the comprehensive intellectual humility scale. Journal of Personality Assessment, 98(2), 209-221), the Difficulties in Emotion Regulation Scale (DERS; Gratz, K. L., & Roemer, L. (2004). Multidimensional assessment of emotion regulation and dysregulation: Development, factor structure, and initial validation of the difficulties in emotion regulation scale. Journal of Psychopathology and Behavioral Assessment, 26(1), 41-54), and the Resistance Vignette Task (RVT; Westra, H. A., Nourazian, N., Poulin, L., Hara, K., Coyne, A., Constantino, M. J., Olson, D., & Antony, M. M. (2021). Testing a deliberate practice workshop for developing appropriate responsivity to resistance markers: A randomized clinical trial. Psychotherapy, 58, 175-185 ) which was used to assess resistance management skill.

RESULTS

Trained individuals performed significantly better on resistance management than untrained individuals; however, years of experience within the trained sample were not associated with resistance management. Conversely, lower humility and greater difficulties regulating emotions were each associated with significantly poorer resistance management in trained individuals.

CONCLUSION

These findings suggest the possibility of improving training to focus on key skills, like resistance management, through supporting humility and emotion regulation in training, as opposed to simply acquiring more experience.

The Resistance Vignette Task: Validating a rapid measure of therapist skill at managing resistance

BACKGROUND

Therapist appropriate responsivity to client ambivalence and resistance is considered an important interpersonal skill to avoid disengagement and ensure a continued collaborative, productive process. The present study examined the predictive validity of the newly developed Resistance Vignette Task (RVT), a 10-item rapidly administered measure of therapist ability to appropriately respond to various presentations of client resistance.

METHODS

Following a resistance management workshop, the concurrent and prospective predictive capacity of RVT scores were examined through test interviews with ambivalent simulators and volunteers.

RESULTS

Prospectively, in test interviews with ambivalent interviewees, higher RVT scores immediately postworkshop were associated with significantly greater responsivity (appropriate responsivity and fewer responsivity errors) at 4-month follow-up. RVT scores at the 4-month follow-up point were also concurrently associated with significantly greater therapist responsivity and lower levels of interviewee resistance.

CONCLUSIONS

These findings provide further validation for the RVT as a measure of therapist responsivity in vivo, in actual interviews by predicting and being concurrently associated with therapist performance in response to client resistance. Thus, the RVT holds promise in advancing therapist training, as well as research on resistance as it represents an efficient measure of this key therapist skill.

Quantifying wintertime O3 and NOx formation with relevance vector machines

This paper uses a machine learning model called a relevance vector machine (RVM) to quantify ozone (O₃) and nitrogen oxides (NO_x) formation under wintertime conditions. Field study measurements were based on previous work described by Olson et al. (2019), where continuous measurements were reported from a wintertime field study in Utah. RVMs were formulated using either O₃ or nitrogen dioxide (NO₂) as the output variable. Values of the correlation coefficient (r²) between predicted and measured concentrations were 0.944 for O₃ and 0.931 for NO₂. RVMs are constructed from the observed measurements and result in sparse model formulations, meaning that only a subset of the data is used to approximate the entire dataset. For this study, the RVM with O₃ as the output variable used only 20% of the measurement data while the RVM with NO₂ used 16%. RVMs were then used as a predictive model to assess the importance of individual precursors. Using O₃ as the output variable, increases in three species resulted in increased O₃ concentrations: hydrogen peroxide (H₂O₂), dinitrogen pentoxide (N₂O₅), and molecular chlorine (Cl₂). For the two termination products measured during the study, nitric acid (HNO₃) and formic acid (CH₂O₂), no change in O₃ concentration was observed. Using NO₂ as the output variable, only increases in N₂O₅ resulted in increased NO₂ concentrations.

Data mining approaches to understanding the formation of secondary organic aerosol

This research used data mining approaches to better understand factors affecting the formation of secondary organic aerosol (SOA). Although numerous laboratory and computational studies have been completed on SOA formation, it is still challenging to determine factors that most influence SOA formation. Experimental data were based on previous work described by Offenberg et al. (2017), where volume concentrations of SOA were measured in 139 laboratory experiments involving the oxidation of single hydrocarbons under different operating conditions. Three different data mining methods were used, including nearest neighbor, decision tree, and pattern mining. Both decision tree and pattern mining approaches identified similar chemical and experimental conditions that were important to SOA formation. Among these important factors included the number of methyl groups for the SOA precursor, the number of rings for the SOA precursor, and the presence of dinitrogen pentoxide (N₂O₅).

The impact of a deliberate practice workshop on therapist demand and support behavior with community volunteers and simulators

The present study used a newly developed simplified coding system, the Therapist Demand and Support Code, to examine specific therapist behaviors in the context of a previously conducted training trial on Deliberate Practice (DP). The parent trial randomized trainees to a DP workshop or its Traditional, more didactic counterpart (Westra et al., 2020). In both groups, trainees were taught to use Support, rather than Demand, for managing ambivalence and resistance, with the DP group having more feedback and practice. In this study, 68 trainees interviewed both an ambivalent community volunteer and an ambivalent simulator 4 month post workshop. The DP group was found to exhibit significantly fewer Demand behaviors than the Traditional group, with the latter also being significantly quicker to use Demand in the interviews. Moreover, the simulator evoked significantly greater Demand from therapists, regardless of the Training group, suggesting the simulators were more resistant. Although therapist use of Support was equal for community volunteers across training groups, Traditional workshop trainees decreased Support when interviewing the more resistant simulators, whereas DP trainees increased their Support with this same group. This is consistent with findings that DP trainees were more appropriately responsive, making fewer Demands following interviewee counterchange talk and using more Support at these times. These results provide some initial validation of the simplified therapist behavior coding system and offer further evidence for the benefits of DP workshop training for managing resistance. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Time series analysis of wintertime O3 and NOx formation using vector autoregressions

Concentrations of 11 species are reported from continuous measurements taken during a wintertime field study in Utah. Time series data for measured species generally displayed strong diurnal patterns. Six species show a diurnal pattern of daytime maximums (NO, NOy, O3, H2O2, CH2O2, and Cl2), while five species show a diurnal pattern of night time maximums (NO2, HONO, ClNO2, HNO3, and N2O5). Vector autoregression analyses were completed to better understand important species influencing the formation of O3 and NOx. For the species studied, r2 values of predicted versus measured concentrations ranged from 0.82-0.99. Fitting parameters for the autoregressive matrix, Π, indicated the importance of species precursors. In addition, values of fitting parameters for Π were relatively insensitive to data size, with variations generally <10%. Variable causation was quantified using the Granger causation method. Assuming O3 and NOx behave as chemical products, reactants (in order of importance) are as follows: H2O2, N2O5, HONO, and ClNO2.

Predicting Thermal Behavior of Secondary Organic Aerosols

Volume concentrations of secondary organic aerosol (SOA) are measured in 139 steady-state, single precursor hydrocarbon oxidation experiments after passing through a temperature controlled inlet. The response to change in temperature is well predicted through a feedforward Artificial Neural Network. The most parsimonious model, as indicated by Akaike's Information Criterion, Corrected (AIC,C), utilizes 11 input variables, a single hidden layer of 4 tanh activation function nodes, and a single linear output function. This model predicts thermal behavior of single precursor aerosols to less than ±5%, which is within the measurement uncertainty, while limiting the problem of overfitting. Prediction of thermal behavior of SOA can be achieved by a concise number of descriptors of the precursor hydrocarbon including the number of internal and external double bonds, number of methyl- and ethyl- functional groups, molecular weight, and number of ring structures, in addition to the volume of SOA formed, and an indicator of which of four oxidant precursors was used to initiate reactions (NOx photo-oxidation, photolysis of H2O2, ozonolysis, or thermal decomposition of N2O5). Additional input variables, such as chamber volumetric residence time, relative humidity, initial concentration of oxides of nitrogen, reacted hydrocarbon concentration, and further descriptors of the precursor hydrocarbon, including carbon number, number of oxygen atoms, and number of aromatic ring structures, lead to over fit models, and are unnecessary for an efficient, accurate predictive model of thermal behavior of SOA. This work indicates that predictive statistical modeling methods may be complementary to descriptive techniques for use in parametrization of air quality models.

Room temperature housing results in premature cancellous bone loss in growing female mice: implications for the mouse as a preclinical model for age-related bone loss

Room temperature housing (22 °C) results in premature cancellous bone loss in female mice. The bone loss was prevented by housing mice at thermoneutral temperature (32 °C). Thermogenesis differs markedly between mice and humans and mild cold stress induced by standard room temperature housing may introduce an unrecognized confounding variable into preclinical studies.

INTRODUCTION

Female mice are often used as preclinical models for osteoporosis but, in contrast to humans, mice exhibit cancellous bone loss during growth. Mice are routinely housed at room temperature (18-23 °C), a strategy that exaggerates physiological differences in thermoregulation between mice (obligatory daily heterotherms) and humans (homeotherms). The purpose of this investigation was to assess whether housing female mice at thermoneutral (temperature range where the basal rate of energy production is at equilibrium with heat loss) alters bone growth, turnover and microarchitecture.

METHODS

Growing (4-week-old) female C57BL/6J and C3H/HeJ mice were housed at either 22 or 32 °C for up to 18 weeks.

RESULTS

C57BL/6J mice housed at 22 °C experienced a 62 % cancellous bone loss from the distal femur metaphysis during the interval from 8 to 18 weeks of age and lesser bone loss from the distal femur epiphysis, whereas cancellous and cortical bone mass in 32 °C-housed mice were unchanged or increased. The impact of thermoneutral housing on cancellous bone was not limited to C57BL/6J mice as C3H/HeJ mice exhibited a similar skeletal response. The beneficial effects of thermoneutral housing on cancellous bone were associated with decreased Ucp1 gene expression in brown adipose tissue, increased bone marrow adiposity, higher rates of bone formation, higher expression levels of osteogenic genes and locally decreased bone resorption.

CONCLUSIONS

Housing female mice at 22 °C resulted in premature cancellous bone loss. Failure to account for species differences in thermoregulation may seriously confound interpretation of studies utilizing mice as preclinical models for osteoporosis.

Towards a standard for the dynamic measurement of pressure based on laser absorption spectroscopy

We describe an approach for creating a standard for the dynamic measurement of pressure based on the measurement of fundamental quantum properties of molecular systems. From the linewidth and intensities of ro-vibrational transitions we plan on making an accurate determination of pressure and temperature. The goal is to achieve an absolute uncertainty for time-varying pressure of 5 % with a measurement rate of 100 kHz, which will in the future serve as a method for the traceable calibration of pressure sensors used in transient processes. To illustrate this concept we have used wavelength modulation spectroscopy (WMS), due to inherent advantages over direct absorption spectroscopy, to perform rapid measurements of carbon dioxide in order to determine the pressure. The system records the full lineshape profile of a single ro-vibrational transition of CO₂ at a repetition rate of 4 kHz and with a systematic measurement uncertainty of 12 % for the linewidth measurement. A series of pressures were measured at a rate of 400 Hz (10 averages) and from these measurements the linewidth was determined with a relative uncertainty of about 0.5 % on average. The pressures measured using WMS have an average difference of 0.6 % from the absolute pressure measured with a capacitance diaphragm sensor.

Gelation, oxygen permeability, and mechanical properties of mammalian and fish gelatin films

The objective of this study was to evaluate the gelation, thermal, mechanical, and oxygen permeability properties of different mammalian, warm- and cold-water fish gelatin solutions and films. Mammalian gelatin solutions had the highest gel set temperatures, followed by warm-water fish and then cold-water fish gelatin solutions. These differences were related to concentrations of imino acids present in each gelatin, with mammalian gelatin having the highest and cold-water fish gelatin having the lowest concentrations. Mammalian and warm-water fish gelatin films contained helical structures, whereas cold-water fish gelatin films were amorphous. This was due to the films being dried at room temperature (23 °C), which was below or near the gelation temperatures of mammalian and warm-water fish gelatin solutions and well above the gelation temperature of cold-water fish gelatin solutions. Tensile strength, percent elongation, and puncture deformation were highest in mammalian gelatin films, followed by warm-water fish gelatin film and then by cold-water fish gelatin films. Oxygen permeability values of cold-water fish gelatin films were significantly lower than those for mammalian gelatin films. These differences were most likely due to higher moisture sorption in mammalian gelatin films, leading to higher oxygen diffusivity.

Trueness, precision, and detectability for sampling and analysis of organic species in airborne particulate matter

Recovery, precision, limits of detection and quantitation, blank levels, calibration linearity, and agreement with certified reference materials were determined for two classes of organic components of airborne particulate matter, polycyclic aromatic hydrocarbons and hopanes, using typical sampling and gas chromatography/mass spectrometry analysis methods. These determinations were based on initial method proficiency tests and on-going internal quality control procedures. Recoveries generally ranged from 75% to 85% for all target analytes and collocated sample precision estimates were generally better than 20% for polycyclic aromatic hydrocarbons and better than 25% for hopanes. Results indicated substantial differences in data quality between the polycyclic aromatic hydrocarbons and hopanes. Polycyclic aromatic hydrocarbons demonstrated better collocated precision, lower method detection limits, lower blank levels, and better agreement with certified reference materials than the hopanes. The most serious area of concern was the disagreement between measured and expected values in the standard reference material for hopanes. With this exception, good data quality was demonstrated for all target analytes on all other data quality indicators.

Amorphous linear aliphatic polyesters for the facile preparation of tunable rapidly degrading elastomeric devices and delivery vectors

A versatile method for preparing amorphous degradable elastomers with tunable properties that can be easily fabricated into a wide variety of shape-specific devices was investigated. Completely amorphous, liquid poly(ester ether) prepolymers with number-average molecular weights between 4 and 6 x 10(3) g/mol were prepared via condensation polymerization. These liquid prepolymers were then thermally cross-linked to form degradable elastomeric structures. The ability to vary the composition of these liquid prepolymers allows for easy control of the mechanical and degradation properties of the resulting elastomeric structures. Materials can be designed to completely degrade in vitro over a range of 30 days to 6 months, while the Young's modulus can be varied over 3 orders of magnitude (G = 0.02-20 MPa). Also, the liquid nature of these prepolymers makes them amenable to a wide variety of fabrication techniques. Using traditional and modified imprint lithography techniques, we have fabricated devices that demonstrate a wide variety of biologically applicable topologies, which could easily be extended to fabricate devices with more complex geometries. Until now, no method has combined this ease and speed of fabrication with the ability to control the mechanical and degradation properties of the resulting elastomers over such a broad range.

Distributions of PM2.5 source strengths for cooking from the Research Triangle Park particulate matter panel study

Emission rates, decay rates, and cooking durations are reported from continuous PM2.5 (particulate matter less than 2.5 microm) concentrations measured using personal DataRam nephelometers (1-min time resolution) from the Research Triangle Park (RTP) PM panel study. The study (n = 37 participants) included monitoring for 7 consecutive days in each of four consecutive seasons (summer 2000 through spring 2001). Cooking episodes (n = 411) were selected using time-activity diaries and criteria for cooking event duration, peak concentration level, and decay curve quality. Averaged across all cooking events, mean source strengths were 36 mg/min (median = 12 mg/min), mean decay rates were 0.27 h(-1) (0.17 h(-1)), and mean cooking durations were 11 min (7 min). Cooking events were further separated into one of seven categories representing cooking method: burned food (oven cooking, toaster, or stovetop cooking), grilling, microwave, toaster oven, frying, oven cooking, and stovetop cooking. The highest mean source strengths were identified from burned food (mean = 470 mg/min), grilling (173 mg/min), and frying (60 mg/ min); differences between both burned food and grilling compared with all remaining cooking methods were statistically significant. Source strengths, decay rates, and cooking durations were also compared by season and typical meal times (8:00 a.m., 12:00 p.m., and 6:00 p.m.); differences were generally not statistically significant for these cases. Mean source strengths using electric appliances were typically a factor of 2 greater than those using gas appliances for identical cooking methods (frying, oven cooking, or stovetop cooking), although in all cases the difference was not statistically significant. Distributions of source strengths and decay rates for cooking events were also compared among study subjects to assess both within- and between-subject variability. Each subject's distribution of source strengths during the study tended to be either lower than the overall study average (and with lower variability) or higher than the overall study average (and with higher variability). No relationships could be found between source strength and either subject characteristics (age, gender, employment status) or home characteristic (daily air exchange rate). The large number of cooking events and the broad range of cooking activities included in this analysis makes the reported distributions of PM2.5 source strengths useful for probabilistic exposure modeling even though the study population was limited.

Chemical characterization of ambient particulate matter near the World Trade Center: elemental carbon, organic carbon, and mass reconstruction

Concentrations of elemental carbon (EC), organic carbon matter (OM), particulate matter less than 2.5 microm (PM2.5), reconstructed soil, trace element oxides, and sulfate are reported from four locations near the World Trade Center (WTC) complex for airborne particulate matter (PM) samples collected from September 2001 through January 2002. Across the four sampling sites, daily mean concentrations ranged from 1.5 to 6.8 microg/m3 for EC, from 10.2 to 31.4 microg/m3 for OM, and from 22.6 to 66.2 microg/m3 for PM2.5. Highest concentrations of PM species were generally measured north and west of the WTC complex. Total carbon matter and sulfate constituted the largest fraction of reconstructed PM2.5 concentrations. Concentrations of PM species across all sites decreased from the period when fires were present at the WTC complex (before December 19, 2001) to the period after the fires. Averaged over all sites, concentrations decreased by 25.6 microg/m3 for PM2.5, 2.7 microg/m3 for EC, and 9.2 microg/m3 for OM from the fire period to after fire period.

Indoor fine particles: the role of terpene emissions from consumer products

Consumer products can emit significant quantities of terpenes, which can react with ozone (O3). Resulting byproducts include compounds with low vapor pressures that contribute to the growth of secondary organic aerosols (SOAs). The focus of this study was to evaluate the potential for SOA growth, in the presence of O3, following the use of a lime-scented liquid air freshener, a pine-scented solid air freshener, a lemon-scented general-purpose cleaner, a wood floor cleaner, and a perfume. Two chamber experiments were performed for each of these five terpene-containing agents, one at an elevated O3 concentration and-the other at a lower O3 concentration. Particle number and mass concentrations increased and O3 concentrations decreased during each experiment. Experiments with terpene-based air fresheners produced the highest increases in particle number and mass concentrations. The results of this study clearly demonstrate that homogeneous reactions between O3 and terpenes from various consumer products can lead to increases in fine particle mass concentrations when these products are used indoors. Particle increases can occur during periods of elevated outdoor O3 concentrations or indoor O3 generation, coupled with elevated terpene releases. Human exposure to fine particles can be reduced by minimizing indoor terpene concentrations or O3 concentrations.

In-home formation and emissions of trihalomethanes: the role of residential dishwashers

This study involved an assessment of chloroform formation due to the use of hypochlorite-containing detergents in dishwashers. The objective of this research was to quantify in-home formation of trihalomethanes, particularly as related to dishwasher usage. A series of 14 flask and 15 laboratory experiments were completed. Flask experiments involved the mixing of food with dishwasher detergent in water for a 12-min reaction period, and were intended to identify chemicals and relative levels of those chemicals that may form from dishwasher usage with different food groups. Liquid concentrations of chloroform ranged from 1 to 41 mg/l. Laboratory experiments involved collection of liquid and gas samples over the course of an operating cycle with an actual residential dishwasher. Background concentrations of chloroform in the water supply were generally between 0 and 10 microg/l; liquid chloroform levels in the wash cycle were typically at least 50 microg/l. Chloroform concentrations were as high as 20 microg/l in the dishwasher headspace. Using mass balance equations for a typical residential house and laboratory results from this research, predicted concentrations resulting from dishwasher usage were similar to typical background concentrations in residential dwellings.

Optical characterization of a nanoscale incommensurate pitch in a new liquid-crystal phase

As a remarkable orientationally ordered soft-condensed matter system, the smectic-C*(alpha) phase exhibits an incommensurate nanoscale helical pitch of more than four smectic layers. Recent theoretical advances predict the existence of a new phase showing a helical pitch of less than four smectic layers (<16 nm). By applying a novel optical technique to the study of freestanding films with increments in thickness of one smectic layer, we have measured the size of this pitch using 633 nm HeNe laser light. Our results confirm the existence of the newly predicted phase in one unique compound.

Effect of enantiomeric excess on surface structures and phase sequences in free-standing liquid-crystal films

We present differential optical reflectivity and null transmission ellipsometry data from several mixtures of MHPBC enantiomers. From this data, we have determined the chiral smectic phase sequence as a function of enantiomeric excess. The data suggest a change in the structure of the smectic-C(*)(alpha) phase and the surface tilt state as the enantiomeric excess is reduced. The results also show that the intermediate phases, smectic C(*)(FI2), smectic C(*)(FI1), and smectic C(*)(alpha), disappear sequentially on reducing the net chirality.

Nonplanar structure of molecular tilt planes in the surface layers of smectic-A free-standing liquid crystal films

We present ellipsometric results from thin free-standing films of one chiral liquid crystal compound. In the bulk SmA range with surface-induced molecular tilt, a nonplanar arrangement of the molecular orientations of the tilted surface layers is found under a small applied electric field.

Molecular orientation arrangements in the smectic-C* variant liquid-crystal phases

Recent experiments have identified three-layer and four-layer distorted helical structures in the smectic liquid-crystal phases Sm C*(FI1) and Sm C*(FI2), respectively. However, no theories have explained the existence of all these phases. A discrete phenomenological model of the free-energy is analyzed and found to predict the stability of distorted three-layer and four-layer structures, as well as simple helical solutions in smectic liquid crystals. A simple physical picture is provided to explain the stability of the phases exhibiting distorted helical structures.

Dramatic effect of an additional CH2 group on the temperature variation of the Sm-C(*)(alpha) short helical pitch

High-resolution differential optical reflectivity was used to study the temperature evolution of the short helical pitch in the Sm-C(*)(alpha) phase of successive members from two liquid-crystal homologous series. With the addition of one CH2 group, the magnitude and temperature evolution of the pitch change dramatically, and the molecular arrangements between consecutive surface layers found in free-standing films change from being anticlinic to synclinic.

Observation of unusual surface ordering in a uniaxial Sm-A phase formed by a highly biaxial compound

We have studied one banana-shaped compound using null-transmission ellipsometry. By studying free-standing films of various thicknesses we confirm that this compound exhibits the Sm-A phase. This is the first banana-shaped compound with a relatively small bend angle (approximately 140 degrees) in which a uniaxial phase has been observed. At the lower temperature end of the Sm-A phase we observe unusual ordering at the surface of the film.

Surface structures and transitions in the smectic-C* phase of one chiral liquid crystal compound

Three optical probes have been employed on free-standing films to study surface structure and transitions of the SmC* phase of one liquid crystal compound. While the interior layers show the SmC* structure, the tilt in adjacent surface layers is found to be anticlinic. The number of anticlinic surface layers grows rapidly as the transition to the SmC*(FI2) phase is approached.

Detailed optical studies of several banana-shaped compounds in liquid crystal B2 phase

Null-transmission ellipsometry has been performed on free-standing films of one compound in the liquid crystal B2 phase. We have studied films of thickness from 1 to 121 layers. One of the compounds used has an unusually wide 59 K window for the B2 phase. The tilt angle was investigated as a function of temperature and found to be constant over this temperature range to within our resolution of 1 degrees. The one-layer films studied exhibit the same structure as the thicker films, and have helped us to refine the optical model for the B2 phase. For thin films we find that modeling a single smectic layer as two uniaxial layers is a better description of the data than a single biaxial layer, but that for thick films the model used does not effect the simulated result appreciably. Preliminary results also find that the surface layers are less tilted than the interior layers, in contrast to rodlike liquid crystals, which show an enhanced surface tilt.

Relative roles of vascular and airspace pressures in ventilator-induced lung injury

OBJECTIVE

To determine whether elevations in pulmonary vascular pressure induced by mechanical ventilation are more injurious than elevations of pulmonary vascular pressure of similar magnitude occurring in the absence of mechanical ventilation.

DESIGN

Prospective comparative laboratory investigation.

SETTING

University research laboratory.

SUBJECTS

Male New Zealand white rabbits.

INTERVENTIONS

Three groups of isolated, perfused rabbit lungs were exposed to cyclic elevation of pulmonary artery pressures arising from either intermittent positive pressure mechanical ventilation or from pulsatile perfusion of lungs held motionless by continuous positive airway pressure. Peak, mean, and nadir pulmonary artery pressures and mean airway pressure were matched between groups (35, 27.4 +/- 0.74, and 20.8 +/- 1.5 mm Hg, and 17.7 +/- 0.22 cm H2O, respectively).

MEASUREMENTS AND MAIN RESULTS

Lungs exposed to elevated pulmonary artery pressures attributable to intermittent positive pressure mechanical ventilation formed more edema (6.8 +/- 1.3 vs. 1.1 +/- 0.9 g/g of lung), displayed more perivascular (61 +/- 26 vs. 15 +/- 13 vessels) and alveolar hemorrhage (76 +/- 11% vs. 26 +/- 18% of alveoli), and underwent larger fractional declines in static compliance (88 +/- 4.4% vs. 48 +/- 25.1% decline) than lungs exposed to similar peak and mean pulmonary artery pressures in the absence of tidal positive pressure ventilation.

CONCLUSIONS

Isolated phasic elevations of pulmonary artery pressure may cause less damage than those occurring during intermittent positive pressure mechanical ventilation, suggesting that cyclic changes in perivascular pressure surrounding extra-alveolar vessels may be important in the genesis of ventilator-induced lung injury.

Optical studies of the smectic-C(*)(alpha) phase layer structure in free-standing films

The layer structure of the smectic-C(*)(alpha) phase of one liquid-crystal compound has been acquired from both differential optical reflectivity and ellipsometry measurements in the free-standing film geometry. The data from both techniques display characteristic oscillations as a function of temperature, which can be described by a model for the film consisting of surface anticlinic layers and an interior short-pitched azimuthal helix. These results are consistent with those found previously for another compound. Depolarized reflected light microscopy is used to study the films when the unique features of the aforementioned oscillations occur.

Optical studies of the liquid crystal B2 phase formed by banana-shaped molecules

Null-transmission ellipsometry and depolarized light microscopy have been performed on free-standing films of three achiral banana-shaped compounds in the B2 phase. Our results support a two-layer unit cell previously proposed to explain the observed antiferroelectricity in thin films and bulk samples. We have studied thicker films than previously reported and have found no deviations in the film structure from the earlier findings. Moreover, we can determine the layer spacing, the molecular tilt from the layer normal, and the three principal indices of refraction in the molecular reference frame.

Ellipsometric studies of synclinic and anticlinic arrangements in liquid crystal films

The molecular arrangements in liquid crystal freestanding films are studied when smectic C* surface ordering occurs above the bulk smectic A to smectic C* transition temperature. Details of the resulting structures are resolved using ellipsometry. The behavior of the film is compound dependent. Below a critical electric field, either a synclinic or anticlinic structure may be present depending on the magnitude of the bulk spontaneous polarization. A model is presented in which the low-field anticlinic arrangement results from the interaction between polarization fluctuations at the two surfaces.

Structure of the liquid-crystal ferrielectric phases as determined by ellipsometry

The unit cell structures of two ferrielectric liquid-crystal phases are determined from ellipsometric studies of freestanding films in a nondistorting rotatable electric field. A highly biaxial mode with out-of-plane distortions describes all of the data from two different compounds. Qualitative and quantitative features of the data rule out alternate models. We also present a detailed explanation for apparent inconsistencies between previous resonant x-ray and optical experiments.

Normal bronchial epithelial cell expression of glutathione transferase P1, glutathione transferase M3, and glutathione peroxidase is low in subjects with bronchogenic carcinoma

Normal bronchial epithelial cells (NBECs) are at risk for damage from inhaled and endogenous oxidative species and from epoxide metabolites of inhaled polycyclic aromatic hydrocarbons. Epidemiological and in vitro data suggest that interindividual variation in this risk may result from variation in NBEC expression of enzymes that inactivate reactive species by conjugating them to glutathione. Quantitative competitive reverse transcription-PCR was used to measure mRNA levels of glutathione transferases (GSTs) and glutathione peroxidases (GSHPxs) in primary NBECs from subjects with or without bronchogenic carcinoma. Mean expression levels (mRNA/10(3) beta-actin mRNA) in NBECs from 23 subjects without bronchogenic carcinoma compared to those from 11 subjects with bronchogenic carcinoma respectively (in parentheses) were: mGST (26.0, 6.11), GSTM3 (0.29, 0.09), combined GSTM1,2,4,5 (0.98, 0.60), GSTT1 (0.84, 0.76), GSTP1 (287, 110), GSHPx (140, 62.1), and GSHPxA (0.43, 0.34). Levels of GSTP1, GSTM3, and GSHPx were significantly (P < 0.05) lower in NBECs from subjects with bronchogenic carcinoma. Further, the gene expression index formed by multiplying the values for mGST x GSTM3 x GSHPx x GSHPxA x GSTP1 had a sensitivity (90%) and specificity (76%) for detecting NBECs from bronchogenic carcinoma subjects that was better than any individual gene. In cultured NBECs derived from eight individuals without bronchogenic carcinoma and incubated under identical conditions such that environmental effects were minimized, the mean level of expression and degree of interindividual variation for each gene evaluated was less than that observed in primary NBECs. Data from these studies support the hypotheses that (a) interindividual variation in risk for bronchogenic carcinoma results in part from interindividual variation in NBEC expression of antioxidant genes; (b) gene expression indices will better identify individuals at risk for bronchogenic carcinoma than individual gene expression values; and (c) both hereditary and environmental exposures contribute to the level of and interindividual variation in gene expression observed in primary NBECs. Many epidemiological studies have been designed to evaluate risk associated with polymorphisms or gene expression levels of putative susceptibility genes based on measurements in surrogate tissues, such as peripheral blood lymphocytes. Based on data presented here, it will be important to include the assessment of NBECs in future studies. Measurement of antioxidant gene expression in NBECs may identify the 5-10% of individuals at risk for bronchogenic carcinoma. Bronchoscopic sampling of NBECs from smokers and ex-smokers then will allow susceptible individuals to be entered into surveillance and/or chemoprevention studies.

Effects of decreased respiratory frequency on ventilator-induced lung injury

To determine if decreased respiratory frequency (ventilatory rate) improves indices of lung damage, 17 sets of isolated, perfused rabbit lungs were ventilated with a peak static airway pressure of 30 cm H(2)O. All lungs were randomized to one of three frequency/peak pulmonary artery pressure combinations: F20P35 (n = 6): ventilatory frequency, 20 breaths/min, and peak pulmonary artery pressure, 35 mm Hg; F3P35 (n = 6), ventilatory frequency, 3 breaths/min, and peak pulmonary artery pressure of 35 mm Hg; or F20P20 (n = 5), ventilatory frequency, 20 breaths/min, and peak pulmonary artery pressure, 20 mm Hg. Mean airway pressure and tidal volume were matched between groups. Mean pulmonary artery pressure and vascular flow were matched between groups F20P35 and F3P35. The F20P35 group showed at least a 4.5-fold greater mean weight gain and a 3-fold greater mean incidence of perivascular hemorrhage than did the comparison groups, all p </= 0.05. F20P35 lungs also displayed more alveolar hemorrhage than did F20P20 lungs (p </= 0.05). We conclude that decreasing respiratory frequency can improve these indices of lung damage, and that limitation of peak pulmonary artery pressure and flow may diminish lung damage for a given ventilatory pattern.

Consequences of vascular flow on lung injury induced by mechanical ventilation

To investigate whether the magnitude of blood flow contributes to ventilator-induced lung injury, 14 sets of isolated rabbit lungs were randomized for perfusion at either 300 (Group A: n = 7) or 900 ml/ min (Group B: n = 7) while ventilated with 30 cm H2O peak static pressure. Control lungs (Group C: n = 7) were ventilated with lower peak static pressure (15 cm H2O) and perfused at 500 ml/min. Weight gain, changes in the ultrafiltration coefficient (DeltaKf) and lung static compliance (CL), and extent of hemorrhage (scored by histology) were compared. Group B had a larger decrease in CL (-13 +/- 11%) than Groups A (2 +/- 6%) and C (5 +/- 5%) (p < 0.05). Group B had more hemorrhage and gained more weight (16.2 +/- 9.5 g) than Groups A (8.7 +/- 3.4 g) and C (1.6 +/- 1.0 g) (p < 0.05 for each pairwise comparison between groups). Finally, Kf (g . min-1 . cm H2O-1 . 100 g-1) increased the most in Group B (DeltaKf = 0.26 +/- 0. 20 versus 0.17 +/- 0.10 in Group A and 0.05 +/- 0.04 in Group C; p < 0.05 for B versus C). We conclude that the intensity of lung perfusion contributes to ventilator- induced lung injury in this model.

And a doctor shall lead them

With managed care reshaping every aspect of health care, physicians need to assume leadership roles more than ever before. This requires skills they don't teach in medical school.

Isolation of Mycoplasma hominis from a brain abscess

Mycoplasma hominis is a commensal in the genital tract of women and has been associated with urogenital and extragenital infections. However, central nervous system infections with this organism in adults are very rare. Here we describe the recovery of M. hominis from a brain abscess associated with a postpartum infection. Seroconversion to the isolated strain was detected by both a metabolic inhibition test and an immunoblotting assay. This case demonstrates the pathogenic potential of M. hominis and the need for rapid recognition of the organism so that appropriate chemotherapeutic intervention can occur.

Familial sudden death syndrome with an abnormal signal-averaged electrocardiogram as a potential marker

Most familial sudden cardiac death syndromes are associated with structural heart disease or 12-lead electrocardiographic abnormalities. Additionally, the utility of signal-averaged electrocardiograms in patients with familial sudden death syndromes has not been examined. We studied a kindred with sudden death to determine whether they could be classified into any of the previously described syndromes and whether an abnormal signal-averaged electrocardiogram is a marker for this trait. Surviving family members had normal 12-lead electrocardiograms and echocardiograms. Two of the patients who died from ventricular arrhythmias had normal hearts on autopsy. Two surviving family members had a clinical history of arrhythmic events; both had abnormal signal-averaged electrocardiograms and inducible ventricular arrhythmias during electrophysiologic studies. The other family members had normal signal-averaged electrocardiograms. This familial sudden death syndrome appears to be unique because the patients have anatomically normal hearts and normal 12-lead electrocardiograms. An abnormal signal-averaged electrocardiogram may be a marker for the sudden death trait.

Progressive supranuclear palsy: neuropathologic and clinical heterogeneity

To investigate potential heterogeneity in progressive supranuclear palsy (PSP), we examined 13 patients with neuropathologically diagnosed PSP. The clinical diagnosis of PSP was made in eight of these individuals, whereas probable AD was the primary diagnosis in the remaining five. In addition to PSP neuropathology, seven of the 13 patients (54%) showed concomitant pathologic changes of Alzheimer's disease (AD), Parkinson's disease (PD), or both disorders. These observations indicate that AD and PD changes coexist with PSP neuropathology in a substantive proportion of patients and provide further evidence of clinical and neuropathologic heterogeneity in neurodegenerative disorders. Moreover, our results suggest that PSP may be underdiagnosed and deserves more prominence in the differential diagnosis of dementing illness.