The postnatal development of the inferior oblique muscle of the cat. I. Isometric twitch and tetanic properties

The postnatal development of the inferior oblique muscle in the cat has been studied with physiological and histochemical techniques. This paper describes the changes with age in isometric twitch and tetanic response characteristics. The twitch amplitude increased and the twitch contraction time (ct) and half-relaxation time (hrt) decreased almost linearly from birth to adulthood. The relation between the strength of nerve stimulation and twitch ct and hrt changed during development with a threshold slow response appearing at 10 weeks. Twitch responses in cats 6 weeks of age or older were of longer duration than in younger cats, in spite of the longer ct and hrt in young cats. Fusion frequency of the tetanic response reached a constant level in muscles 6 weeks or older. The maximum rate of tension rise remained the same from birth to 6 weeks of age and later increased markedly up to 20 weeks of age. The contracture induced by succinylcholine was the same in muscles of all ages. These data were related to previous findings on the postnatal development of fast and slow muscles and motor units in the hindlimb of the cat. A differentiation of the development of fast and slow eye muscle fibers is suggested. Slow fibres seemed to have completed their maturation at about ten weeks of age, while the development of fast fibre properties continued, probably up to the adult stage.     

Blockade of stimulant-induced preprodynorphin mRNA expression in the striatal matrix by serotonin depletion

Cocaine and methamphetamine (METH) induce preprodynorphin (PPD) mRNA expression in the striatum. Cocaine induces PPD expression in both the patch and matrix compartments of the rostral striatum, whereas METH induces PPD expression in the patch compartment of the rostral striatum. In middle striatum, both stimulants increase PPD expression in the patch and matrix compartments. METH and cocaine treatment also increase extracellular serotonin (5-HT). Several studies have shown that 5-HT receptors are present on striatonigral neurons that express PPD mRNA, and that 5-HT is a positive regulator of striatal neuropeptide expression. The current study examined whether 5-HT plays a role in the patch/matrix expression of PPD mRNA induced by cocaine and METH in striatum. Male Sprague-Dawley rats were treated with p-chloroamphetamine (PCA; 8 mg/kg, i.p), a serotonin neurotoxin, 1 week prior to cocaine (30 mg/kg, i.p) and METH (15 mg/kg, s.c.) treatment. The 80% loss of 5-HT induced by PCA-pretreatment blocked cocaine-induced PPD expression in the rostral matrix compartment. Cocaine- and METH-induced PPD expression in the rostral patch compartment was unaffected by PCA-pretreatment. PCA-pretreatment also decreased both cocaine- and METH-induced PPD expression in the matrix, but not patch of middle striatum. PCA-induced 5-HT depletion did not affect stimulant-induced increases in PPT mRNA expression in the striatum. These data suggest that 5-HT plays a role in stimulant-induced PPD expression in the matrix compartment of rostral and middle striatum. Thus, 5-HT innervation may play a critical role in basal ganglia function.     

Smokeless tobacco use among United States Air Force trainees

Background: The prevalence of smokeless tobacco use in the United States Air Force (USAF) exceeds civilian use rates. The prevalence and correlates of smokeless tobacco use were assessed and evaluated in a sample of USAF trainees. Methods: We conducted a cross-sectional survey of USAF technical training school personnel at Joint Base San Antonio-Lackland and Fort Sam Houston (N = 14,810). Survey completion rate was 78%. Logistic regression was used to analyze the associations between demographic variables, tobacco use, and social factors for both regular and infrequent smokeless tobacco (e.g., chewing tobacco, snuff) users. Results: Overall, 16% of Airmen had ever used smokeless tobacco and 10% regularly used smokeless tobacco. In multivariate analyses, men had greater odds than women of regular smokeless tobacco use (adjusted odds ratio [OR] = 15.2; 95% confidence interval [CI]: 10.8–21.5) and infrequent smokeless tobacco use (adjusted OR = 4.2; 95% CI: 3.1–5.7). Smokeless tobacco use was associated with participation in high school sports (adjusted OR = 1.9; 95% CI: 1.6–2.3 for regular users; adjusted OR = 1.4; 95% CI: 1.1–1.7 for infrequent users), smoking cigarettes (adjusted OR = 4.3; 95% CI: 3.6–5.1 for regular users; adjusted OR = 4.0; 95% CI: 3.2–5.0 for infrequent users), or living with someone who used smokeless tobacco (adjusted OR = 2.2; 95% CI: 1.9–2.6 for regular users; adjusted OR = 1.4; 95% CI: 1.1–1.7 for infrequent users). Black or African Americans were less likely than whites to be regular (adjusted OR = 0.3; 95% CI: 0.1–0.4) or infrequent (adjusted OR = 0.3; 95% CI: 0.2–0.4) users of smokeless tobacco. Conclusions: Smokeless tobacco use among incoming Air Force recruits is common and negatively impacts the Air Force's goal to be tobacco-free. Understanding sociodemographic characteristics perpetuating smokeless tobacco use in the Air Force population can inform the development of health promotion interventions.     

Association of the -159 CD14 gene polymorphism and lack of association of the -308 TNFA and Q551R IL-4RA polymorphisms with severe chronic periodontitis in Swedish Caucasians

BACKGROUND: Severe forms of periodontitis are suggested to have a genetic basis. OBJECTIVE: The aim of the present investigation was to study the association of gene polymorphisms related to some immune regulation components (G-308A TNFA, Q551R IL-4RA and C-159T CD14) with severe chronic periodontitis. MATERIALS AND METHODS: Sixty patients (aged 36-74 years; mean 54.5+/-8.5) with severe and generalized chronic periodontitis were included. The patients exhibited bone loss >50% at all teeth. Thirty-nine periodontally healthy subjects between 35 and 78 years of age (mean 51.0+/-10.9) were recruited as controls. DNA was isolated from peripheral blood cells and genotyping was performed by combination of PCR and restriction endonuclease mapping. RESULTS: While gene polymorphisms for TNFA and IL-4RA did not show any association with severe chronic periodontitis, the analysis of the -159 CD14 gene polymorphism revealed significant differences between test and control groups. The proportion of subjects that exhibited the TT genotype was significantly smaller in the group with severe periodontitis than in periodontal healthy group (p=0.028; Fisher's exact test). The C allele carriage was 90% in the periodontitis group and significantly higher than in the healthy control group (72%). CONCLUSION: It is suggested that the -159 CD14 gene polymorphism is associated with chronic periodontitis in Caucasian subjects of a north European origin.     

Reticulated phototoxic eruption in a patient on long-term diltiazem therapy

Diltiazem hydrochloride is a commonly prescribed medication in the treatment of cardiovascular disease. A case of diltiazem-induced hyperpigmentation in a patient after significant sun exposure is reported. The morphological appearance was reticulated and slate-gray to blue in color. The pathogenesis of the hyperpigmentation is discussed and possible treatment options are reviewed.     

Differential regional effects of methamphetamine on dopamine transport

Multiple high-dose methamphetamine administrations cause long-lasting (>1 week) deficits in striatal dopaminergic neuronal function. This stimulant likewise causes rapid (within 1 h) and persistent (at least 48 h) decreases in activities of striatal: 1) dopamine transporters, as assessed in synaptosomes; and 2) vesicular monoamine transporter -2 (VMAT-2), as assessed in a non-membrane-associated (referred to herein as cytoplasmic) vesicular subcellular fraction. Importantly, not all brain areas are vulnerable to methamphetamine-induced long-lasting deficits. Similarly, the present study indicates that methamphetamine exerts differential acute effects on monoaminergic transporters according to brain region. In particular, results revealed that in the nucleus accumbens, methamphetamine rapidly, but reversibly (within 24 h), decreased plasmalemmal dopamine transporter function, without effect on plasmalemmal dopamine transporter immunoreactivity. Methamphetamine also rapidly and reversibly (within 48 h) decreased cytoplasmic VMAT-2 function in this region, with relatively little effect on cytoplasmic VMAT-2 immunoreactivity. In contrast, methamphetamine did not alter either dopamine transporter or VMAT-2 activity in the hypothalamus. Noteworthy, the nucleus accumbens and hypothalamus did not display the persistent long-lasting striatal dopamine depletions caused by the stimulant. Taken together, these data suggest that deficits in plasmalemmal and vesicular monoamine transporter activity lasting greater than 24-48 h may be linked to the long-lasting dopaminergic deficits caused by methamphetamine and appear to be region specific.     

Induced Microphase Separation in Hybrid Composite Polymer Electrolytes Based on Poly(acrylonitrile‐r‐butadienes) and Ionic Liquids

Novel hybrid, composite polymer electrolytes (HCPEs) based on poly(acrylonitrile‐r‐butadiene) (PAN‐r‐PB), CN‐modified silica nanoparticles (CN‐MSNs), Li triflate, and ionic liquids (ILs) are synthesized. Using a combination of methods, it is demonstrated that these materials segregate into PAN‐rich and PB‐rich phases, the behavior of which changes depending on the IL type. The incorporation of ILs containing hexyl and octyl substituents at the imidazolium rings leads to a higher mobility of the PB‐rich phase and a decrease of the density of the neighboring PAN‐rich phase, allowing an improvement of the Li ion conductivity. However, with an increase of the substituent length from decyl to dodecyl, ordering of the hydrophobic tails in the PB‐rich phase leads to both stiffening of the latter and corresponding ordering of the ionic pairs of ILs, resulting in a decreased conductivity. The results of this work are broadly applicable for controlling the structure and properties of polymeric materials exhibiting microphase segregation.