CASE DEFINITION AND TREATMENT TRIAL OF TETANY SYNDROME IN PANAMANIAN GOLDEN FROGS (ATELOPUS ZETEKI).

The mass extinction of amphibians necessitates specialized programs to ensure species' survival. Maryland Zoo in Baltimore houses the largest assurance population of the critically endangered Panamanian golden frog (Atelopus zeteki). However, individuals in this population experience a tetany-like syndrome, characterized by rigid/inappropriately positioned limbs and difficulty hopping, swimming, and righting. In this study, a syndrome case definition was assigned and the associated clinical signs were described. Then, four different treatments were systematically assessed in order to find the most effective protocol for treatment and begin to elucidate its underlying causes. Eighty-three frogs fulfilled the case definition and were treated orally for 14 d with either calcium gluconate, magnesium chloride, supplemental gavage feeding, or combination of calcium, magnesium, and vitamin B complex. Frogs were tested with a defined protocol assessing hopping, righting, and swimming abilities. Testing was performed at symptom onset and repeated weekly until resolution occurred. Analyses revealed that combination treatment was significantly more effective in eliminating clinical signs of tetany syndrome. Results show the most effective way to treat this syndrome, but do not help elucidate the underlying cause. Future work will focus on examining factors (e.g., diet, husbandry) that may elicit the syndrome for a more complete understanding of its etiology.

Functional trade-offs in white matter axonal scaling.

The brains of large mammals have lower rates of metabolism than those of small mammals, but the functional consequences of this scaling are not well understood. An attractive target for analysis is axons, whose size, speed and energy consumption are straightforwardly related. Here we show that from shrews to whales, the composition of white matter shifts from compact, slow-conducting, and energetically expensive unmyelinated axons to large, fast-conducting, and energetically inexpensive myelinated axons. The fastest axons have conduction times of 1-5 ms across the neocortex and <1 ms from the eye to the brain, suggesting that in select sets of communicating fibers, large brains reduce transmission delays and metabolic firing costs at the expense of increased volume. Delays and potential imprecision in cross-brain conduction times are especially great in unmyelinated axons, which may transmit information via firing rate rather than precise spike timing. In neocortex, axon size distributions can account for the scaling of per-volume metabolic rate and suggest a maximum supportable firing rate, averaged across all axons, of 7 +/- 2 Hz. Axon size distributions also account for the scaling of white matter volume with respect to brain size. The heterogeneous white matter composition found in large brains thus reflects a metabolically constrained trade-off that reduces both volume and conduction time.

Factors associated with smokeless tobacco cessation in an Appalachian population.

Identifying factors associated with successful tobacco quit attempts may help in the development and targeting of effective cessation strategies. This paper aims to describe factors associated with smokeless tobacco (ST) cessation and compares the results to findings in the smoking cessation literature. Prospective data on 116 men aged 19 to 70 and participating in a ST cessation program were used to examine correlates of successful ST cessation at 1-year post-intervention. Controlling for age, level of education (p=0.002) and daily coffee consumption (p=0.005) had significant independent associations with successful cessation. No ST use variables were significant predictors of cessation success. In a multivariable logistic regression model three factors were significantly associated with cessation: education (p=0.010), coffee consumption (p=0.019), and age (p=0.029). Factors associated with successful ST cessation in this sample are consistent with predictors of smoking cessation reported in the literature. Based on its widespread use and the strength of its association with successful quitting, the role of caffeine consumption in ST cessation merits further study.

Smokeless tobacco use and salivary cotinine concentration.

The objective of the current study was to examine demographic, tobacco-related, and psychosocial factors associated with cotinine concentration in a group of 256 male smokeless tobacco (ST) users living in the Ohio Appalachian region. Participants completed a survey that included questions on: 1) current and past tobacco use behaviors; 2) demographics; 3) tobacco dependence; 4) decisional balance; 5) health behaviors; and 6) perceived stress and depressive symptoms. Saliva samples were obtained for measurement of cotinine. The variables related to salivary cotinine concentration in the multiple regression model were age, marital status, occupation, quit attempts, years of ST use, and tobacco dependence score (adjusted R(2)=0.24). Among the 199 snuff only users, cotinine concentration was positively related to age, being divorced/widowed/separated, no quit attempts in the previous year, dependence score, and brand of snuff (adjusted R(2)=0.29). This is one of the largest studies to examine influences beyond topography on cotinine concentration in a group of rural ST users. These findings suggest that smokeless tobacco users and smokers share some similarities with respect to tobacco dependence.

A measure of nicotine dependence for smokeless tobacco users.

The objective of the present study was to examine the properties of a modification of the Fagerström Test of Nicotine Dependence in a large sample of smokeless tobacco (ST) users. The subjects for this study included 256 males who were recruited for a tobacco cessation intervention that involved a visit with a dentist and advice to quit smoking during the exam. At baseline, the modified dependence scale was administered to the participants and a saliva sample was collected to measure cotinine. The correlation between the total score and salivary cotinine was moderate among the ST only users (r=0.34), whereas it was lower (r=0.19) among the ST+cigarette users. Among ST only users, the coefficient alpha was 0.40; however it was considerably higher among the ST+cigarettes group (alpha=0.61). In both cases, the coefficient alpha was lower than the recommended value of 0.70. Future research should focus on refining questionnaires that more precisely measure nicotine dependence in smokeless tobacco users.

Norgestimate and medroxyprogesterone acetate do not attenuate the atheroprotective effects of 17beta-estradiol in ovariectomized, apolipoprotein E-deficient mice.

OBJECTIVE: To determine whether progestins counteract the cardioprotective effects of estrogen. DESIGN: Controlled animal study. SETTING: Academic laboratory environment. ANIMAL(S): Female apolipoprotein E-deficient mice. INTERVENTION(S): Mice were randomly assigned to groups receiving a sham operation plus placebo pellet, bilateral gonadectomy plus placebo pellet, or gonadectomy plus one of nine combinations of estrogen/progestin SC pellets. MAIN OUTCOME MEASURE(S): Total plasma cholesterol, body weight, fat depot weight, uterine weight and size, and the cross-sectional area of fatty streaks in the aortic sinus were measured in each animal. RESULT(S): After 8 weeks of treatment, plasma cholesterol levels were significantly higher only in the ovariectomized and sham-operated animals that received placebo pellets. No differences in plasma cholesterol were observed relative to the type or amount of progestin administered. There was a reduction in fatty streaks in all of the hormone treatment groups as compared with both the ovariectomized and sham-operated animals that received placebo pellets. CONCLUSION(S): There were no significant differences in lesion area in response to estrogen alone or to estrogen plus the different types and doses of progestins.

Evaluation of screening tools for dementia in older adults with mental retardation.

We compared groups with and without diagnosed dementia matched on IQ, age, and presence of Down syndrome. The Dementia Scale for Down Syndrome and Dementia Questionnaire for Mentally Retarded Persons were used to assess participants. We developed two performance tasks to determine whether they were useful in separating subjects with and without dementia and also used the Reiss Screen. Both dementia scales and both performance tasks discriminated between groups. The dementia scales were not related to premorbid IQ, age, or gender, whereas performance tasks were related to dementia and IQ but not age or gender. Various Reiss Screen subscales also discriminated between groups. Subscales of the screening instruments and performance tasks were significantly related, indicating congruent validity. Logistic regression was conducted to assess which combination of tests discriminated best between groups.

Simvastatin inhibits expression of tissue factor in advanced atherosclerotic lesions of apolipoprotein E deficient mice independently of lipid lowering: potential role of simvastatin-mediated inhibition of Egr-1 expression and activation.

Recent studies suggest that the beneficial effects of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors (statins) in reducing cardiovascular events may in part, be independent of their capacity to lower plasma lipids. To test this hypothesis, simvastatin (50 mg/kg/d) was administered to 30-week-old apolipoprotein E deficient mice (apo E-/-) for 12, 18 and 24 weeks. In contrast to other experimental models and humans, simvastatin treatment increases plasma cholesterol levels in apo E-/- mice. Quantitative real-time polymerase chain reaction was used to quantify expression of tissue factor (TF) and monocyte chemoattractant protein-1 (MCP-1) in the aorta of each mouse. Expression of TF was reduced to 34, 24, and 13% of control levels at 12, 18 and 24 weeks, respectively, of simvastatin administration. Advanced lesions in the innominate arteries of the simvastatin treated mice had reduced levels of TF, fewer macrophages and reduced expression of early growth response-1 (Egr-1). In vitro studies in mouse macrophages demonstrated decreased lipopolysaccharide induced binding of nuclear proteins to the Egr-1 consensus DNA sequence following pretreatment with simvastatin. RNA levels for MCP-1 were reduced to 30% of control values following 24 weeks of simvastatin treatment. In conclusion, these data suggest that chronic administration of simvastatin to older apo E-/- mice can inhibit the expression of pro-thrombotic/pro-inflammatory genes within established atherosclerotic lesions via mechanisms that are independent of reductions in plasma lipids.