Paradox of serial interferon-gamma release assays: variability width more important than specificity size.

SETTING: Serial screening for latent tuberculous infection (LTBI) is commonly performed in certain populations, such as health care workers. The high apparent conversion rate in some studies of interferon-gamma release assays is puzzling given the claimed high specificity of these tests. OBJECTIVE: To understand how test-retest variability, specificity, and underlying LTBI prevalence affect observed outcomes of repeated testing for LTBI. DESIGN: Mathematical model assuming constant test sensitivity and specificity over time and no new infections. RESULTS: Test-retest variability had a large effect on the observed proportion of conversions (initial negative test, followed by a positive test) and reversions (initial positive test, followed by a negative test). For example, a test with 70% specificity and 5% test-retest variability would be associated with a conversion rate of 3.7% and a reversion rate of 7.7%, while a test with 95% specificity but 10% test-retest variability would be associated with a conversion rate of 5.5% and a reversion rate of 57%, assuming that both tests are 80% sensitive and underlying LTBI prevalence was 5%. CONCLUSION: Test-retest variability is a key parameter that should be reported for tests used for serial screening for LTBI. Reducing test-retest variability can reduce false-positive and false-negative results.

Tuberculosis testing in correctional officers: a national random survey of jails in the United States.

SETTING: The correctional system in the United States is large and growing. The Centers for Disease Control and Prevention recommend baseline and annual testing of employees in correctional facilities for latent tuberculosis infection (LTBI). OBJECTIVE: To describe the extent of and factors associated with LTBI testing practices for jail correctional officers. DESIGN: A national survey of 1760 randomly selected jails was conducted. We used multivariable logistic regression models to examine factors associated with testing officers in a guideline-concordant manner and having a written policy. RESULTS: A total of 1174 (67%) surveys were returned. Only 52% of jails had a written policy on LTBI testing of officers, and 51% screened officers at least annually (guideline concordance). Large jails (OR 2.41, 95%CI 1.67-3.49) and jails in states with a high tuberculosis incidence (OR 1.67, 95%CI 1.17-2.38) and in the Midwest (OR 1.58, 95%CI 1.07-2.33) were more likely to screen in a guideline-concordant manner. CONCLUSION: Screening for LTBI among correctional officers in the United States was inconsistent. Strategies to improve LTBI testing among correctional officers are needed.

Pacemaker wire infection with Mycobacterium tuberculosis: a case report and literature review.

Post-operative reactivation of Mycobacterium tuberculosis (TB) is a recognized complication of surgery. We report a case of reactivation TB involving pacemaker wires and review the literature on surgical site TB infections following cardiac surgery to examine the clinical features and outcomes of this rare but important presentation of TB.

Sense of self: voices of separation and connection in women who have experienced abuse.

The findings of qualitative studies with women who have experienced abuse by an intimate partner suggest that a woman's sense of self is a central feature in her decision to leave the abusive relationship. This qualitative study was undertaken, in part, to listen to how women describe themselves, specifically explicating voices of relational connection and disconnection within the narratives. This paper presents the findings of interviews with 18 rural women from culturally diverse backgrounds who had been or were currently in abusive relationships. The women were asked to respond to the question "How would you describe yourself to yourself?" The responses were read using the interpretive method of reading narratives for self and moral voice. The theory of moral development was used to frame the inquiry. The experiences of self that emerged from the narratives are presented as progressively relational voices of separation and connection. The relationship between these voices and moral development is discussed, as are implications for nursing practice and for future research.

Why did she do that? Issues of moral conflict in battered women's decision making.

This qualitative research study was undertaken, in part, in an effort to develop an understanding of decisions experienced as moral conflicts by women who have experienced abuse by an intimate partner. Eighteen rural women who had been or were currently in an abusive relationship with a male partner participated in the study. An adaptation of the Real-Life Moral Conflict and Choice Interview (L. M. Brown, 1988) was used to gather and interpret the data. This method required each participant to describe a real life dilemma and her response to that dilemma. In this article the author discusses the types of decisions described by the women. The decisions are organized into 3 categories that emerged from the interview narratives: the decision to leave the abusive relationship, decisions that threaten sense of self, and decisions of resistance. The findings of this study make explicit some of the dimensions of moral conflict inherent in decisions battered women make. Explication of these moral conflict issues and the ways in which women seek to resolve them provide another avenue through which to understand a battered woman's life, a perspective not found in other studies.

Seasonal acclimation of prairie deer mice.

Prairie deer mice responded to long nights by reducing their metabolic rates, core temperatures, thermal conductances and incremental metabolic responses to cold stimulus, while increasing their capacities for nonshivering thermogenesis. Some winter animals spontaneously entered daily torpor in the mornings and thereby further reduced their metabolic rates and core temperatures. Provision of exogenous melatonin (by subdermal implants) mimiced short photoperiod effects on metabolic rates and core temperatures of wild-caught, laboratory maintained animals. Provision of supplemental dietary tryptophan to laboratory animals conditioned to natural light cycles mimiced metabolic effects of long nights in summer animals, and further reduced metabolic rates of winter mice, but did not affect their core temperature levels. Newly caught, laboratory maintained deer mice responded to natural seasonal clues of short-photoperiod and increased dietary tryptophan by reducing their resting energy requirements through both lower metabolic and lower core temperature levels. Short photoperiod and seasonal change also promoted gonadal involution, and resulted in more socially tolerant huddling by mice with reduced core temperature. Reduced 24-hour LH excretion rates were also observed in winter animals which were exposed to seasonal light cycles at warm (25 degrees C) room temperatures. We propose that seasonal acclimatization involves pineal effects on sex hormone-influenced social behaviors and on resting metabolism. These effects serve to conserve resting energy expenditure and promote hypothermic insulation by wild prairie deer mice.

Season affects tolerance of cohabitation by deer mice.

We measured the resting metabolic rates of Peromyscus maniculatus for 7 days before and 7 days following forced pairing in order to determine whether seasonal light cycles influenced the rates of behavioral and metabolic habituation of deer mice to cohabitation. We had earlier shown that winter photoperiod and/or huddling results in lower resting metabolic rates and core temperatures of deer mice. Seasonal photoperiods were simulated by conditioning wild-caught mice to 24-h light cycles with differing durations of light exposure during the 24 h day. These experiments demonstrated that winter mice adjusted their resting metabolic rates from solitary to huddling levels much more rapidly than summer mice. Initial, high metabolic rate responses of paired mice persisted much longer than expressions of agonistic behaviors between paired mice. We propose that winter photoperiod enables animals to more efficiently make the transition to spontaneous, amicable huddling as a winter acclimatization strategy.

Differential effects of adrenergic blockade on seasonal changes in core temperatures and thermal conductances of deer mice maintained in thermal neutral environments.

1. Resting, daytime, thermal conductances and metabolic rates of mice conditioned to winter (10:14LD) and summer (14:10LD) photoperiods were reduced by social huddling; huddling resulted in group size related elevations in core temperature during summer, but not with winter light-dark cycle exposures. 2. Core temperatures of resting, solitary winter animals were lower than those of summer; both summer and winter animals' core temperatures were further reduced by increased thermal conductance resulting from (phentolamine) alpha receptor blockade. 3. Social huddling reduction of the heat loss from phentolamine treatment was more effective for winter (10:14LD) animals. 4. While phentolamine treatment resulted in increased thermal conductance and lower core temperatures of the mice, propranalol treatment resulted in lower core temperatures and resting metabolic rates, with a resulting decrease in thermal conductance. 5. Since adrenergic blockade was less dose-effective on winter animals, we reasoned that winter animals display higher levels of endogenous adrenergic capacity than summer animals and that lower winter thermoregulatory set points provide for energy conservation with enhanced capacity for meeting cold challenge.

Photoperiodic adjustment of thermal conductance in deer mice.

Seasonal changes in metabolic rate can be induced in mice held in thermal neutral (26-29 degrees C) ambient temperatures. The metabolic effect of winter photoperiod is a lower metabolic rate without compromise to metabolic reserve. Manipulations of photoperiod or melatonin backgrounds adjust the thermoregulatory setting for core temperature level and affect thermal conductance.

Bioenergetic benefits of huddling by deer mice (Peromyscus maniculatus).

Both short photoperiod and communal social living conserve metabolic energy by deer mice held in thermal neutral ambient temperatures. Initial socialization was energetically more costly than solitary living, but huddling behaviors reduced thermal conductance and mass specific metabolic rate by 30% within 5 days. While short photoperiod reduced metabolic energy expenditure by decreasing thermoregulatory demand, huddling mediated behavioral conservation was achieved with hyperthermic core temperatures.

Metabolic and thermoregulatory effects of photoperiod and melatonin on Peromyscus maniculatus acclimatization.

A photoperiod-related seasonal rhythm in active period (scotophase), metabolic rate and core temperature was documented for animals held at 21.0 +/- 0.1 degrees C ambient; animals that were habituated to long nights (10:14LD) had a greater metabolic reserve than those held in summer photoperiods (14:10LD). While relative weights of gonads and sex accessory tissues of mice show typical "winter" regression, interscapular brown adipose tissue mass was unaffected by photoperiod; moreover, IBAT beta adrenergic responses under "winter" photoperiods did not differ from "summer" photoperiods in the absence of cold stimulus. Thermogenic efficiency, measured as the increment of active temperature level achieved per increment of active period metabolic effort, was highest for animals exposed to short photoperiods. Thermal conductance was reduced in animals exposed to short (10:14LD) photoperiods. Heat conservation and thermogenic response capacity was enhanced by melatonin treatment and short photoperiod.

Efficacy of alpha-chlorhydrin in sewer rat control.

A single application of the male chemosterilant, alpha-chlorhydrin, to a problem sewer rat infestation resulted in reductions of rat numbers and distribution which was comparable to effects of warfarin baiting methods. Rat numbers were reduced by more than 85% by both methods. More rapid mortality and recruitment were evident for warfarin effects; the alpha-chlorhydrin treated population had a longer lag phase of growth so that reinfestation of sewer habitat to pre-treatment numbers, and distribution over a 40 square block area, required approximately 1.5-2 times longer after alpha-chlorhydrin treatment when compared with warfarin treatment. Comparisons of changes in rat densities in infested sewers following the two treatments indicate that recovery of warfarin treated populations is achieved by reproductive recruitment followed by dispersal while alpha-chlorhydrin treated populations recover by slower immigration and later reproductive recruitment. Alpha-chlorohydrin should be a useful addition to a limited arsenal of rat control agents because of its specificity for the Norway rat, its single dose effectiveness as a toxicant-chemosterilant, and its short environmental half-life.