How Menthol Alters Tobacco-Smoking Behavior: A Biological Perspective.

Mentholated cigarettes gained popularity in the 1950s and were often marketed as "healthy" cigarettes, attributable to their pleasurable mint flavor and cooling sensation in the mouth, lungs, and throat. While it is clear that nicotine is the primary psychoactive component in tobacco cigarettes, recent work has suggested that menthol may also play a role in exacerbating smoking behavior, despite original health claims. Recent evidence highlights four distinct biological mechanisms that can alter smoking behavior: 1) menthol acts to reduce the initially aversive experiences associated with tobacco smoking; 2) menthol can serve as a highly reinforcing sensory cue when associated with nicotine and promote smoking behavior; 3) menthol's actions on nicotinic acetylcholine receptors may change the reinforcing value of nicotine; and 4) menthol can alter nicotine metabolism, thus increasing nicotine bioavailability. The purpose of this review is to highlight and evaluate potential biological mechanisms by which menthol can alter smoking behavior.

Distinct effects of ventral tegmental area NMDA and acetylcholine receptor blockade on conditioned reinforcement produced by food-associated cues.

Stimuli paired with rewards acquire reinforcing properties to promote reward-seeking behavior. Previous work supports the role of ventral tegmental area (VTA) nicotinic acetylcholine receptors (nAChRs) in mediating conditioned reinforcement elicited by drug-associated cues. However, it is not known whether these cholinergic mechanisms are specific to drug-associated cues or whether VTA cholinergic mechanisms also underlie the ability of cues paired with natural rewards to act as conditioned reinforcers. Burst firing of VTA dopamine (DA) neurons and the subsequent phasic DA release in the nucleus accumbens (NAc) plays an important role in cue-mediated behavior and in the ability of cues to acquire reinforcing properties. In the VTA, both AChRs and N-methyl-d-aspartate receptors (NMDARs) regulate DA burst firing and phasic DA release. Here, we tested the role of VTA nAChRs, muscarinic AChRs (mAChRs), and NMDARs in the conditioned reinforcement elicited by a food-associated, natural reward cue. Subjects received 10 consecutive days of Pavlovian conditioning training where lever extension served as a predictive cue for food availability. On day 11, rats received bilateral VTA infusion of saline, AP-5 (0.1 or 1µg), mecamylamine (MEC: 3 or 30µg) or scopolamine (SCOP: 3 or 66.7µg) immediately prior to the conditioned reinforcement test. During the test, nosepoking into the active (conditioned reinforced, CR) noseport produced a lever cue while nosepoking on the inactive (non-conditioned reinforced, NCR) noseport had no consequence. AP-5 robustly attenuated conditioned reinforcement and blocked discrimination between CR and NCR noseports at the 1-µg dose. MEC infusion decreased responding for both CR and NCR while 66.7-µg SCOP disrupted the subject's ability to discriminate between CR and NCR. Together, our data suggest that VTA NMDARs and mAChRs, but not nAChRs, play a role in the ability of natural reward-associated cues to act as conditioned reinforcers.

Ventral tegmental area cholinergic mechanisms mediate behavioral responses in the forced swim test.

Recent studies revealed a causal link between ventral tegmental area (VTA) phasic dopamine (DA) activity and pro-depressive and antidepressant-like behavioral responses in rodent models of depression. Cholinergic activity in the VTA has been demonstrated to regulate phasic DA activity, but the role of VTA cholinergic mechanisms in depression-related behavior is unclear. The goal of this study was to determine whether pharmacological manipulation of VTA cholinergic activity altered behavioral responding in the forced swim test (FST) in rats. Here, male Sprague-Dawley rats received systemic or VTA-specific administration of the acetylcholinesterase inhibitor, physostigmine (systemic; 0.06 or 0.125mg/kg, intra-cranial; 1 or 2µg/side), the muscarinic acetylcholine receptor (AChR) antagonist scopolamine (2.4 or 24µg/side), or the nicotinic AChR antagonist mecamylamine (3 or 30µg/side), prior to the FST test session. In control experiments, locomotor activity was also examined following systemic and intra-cranial administration of cholinergic drugs. Physostigmine administration, either systemically or directly into the VTA, significantly increased immobility time in FST, whereas physostigmine infusion into a dorsal control site did not alter immobility time. In contrast, VTA infusion of either scopolamine or mecamylamine decreased immobility time, consistent with an antidepressant-like effect. Finally, the VTA physostigmine-induced increase in immobility was blocked by co-administration with scopolamine, but unaltered by co-administration with mecamylamine. These data show that enhancing VTA cholinergic tone and blocking VTA AChRs has opposing effects in FST. Together, the findings provide evidence for a role of VTA cholinergic mechanisms in behavioral responses in FST.

Monte Carlo phase diagram for diblock copolymer melts.

A partial phase diagram is constructed for diblock copolymer melts using lattice-based Monte Carlo simulations. This is done by locating the order-disorder transition (ODT) with the aid of a recently proposed order parameter and identifying the ordered phase over a wide range of copolymer compositions (0.2

Influence of compression therapy on symptoms following soft tissue injury from maximal eccentric exercise.

STUDY DESIGN: A between groups design was used to compare recovery following eccentric muscle damage under 2 experimental conditions. OBJECTIVE: To determine if a compression sleeve donned immediately after maximal eccentric exercise would enhance recovery of physical function and decrease symptoms of soreness. BACKGROUND: Prior investigations using ice, intermittent compression, or exercise have not shown efficacy in relieving symptoms of delayed onset muscle soreness (DOMS). To date, no study has shown the effect of continuous compression on DOMS, yet this would offer a low cost intervention for patients suffering with the symptoms of DOMS. METHODS AND MEASURES: Twenty nonimpaired non-strength-trained women participated in the study. Subjects were matched for age, anthropometric data, and one repetition maximum concentric arm curl strength and then randomly placed into a control group (n = 10) or an experimental compression sleeve group (n = 10). Subjects were instructed to avoid pain-relieving modalities (eg, analgesic medications, ice) throughout the study. The experimental group wore a compressive sleeve garment for 5 days following eccentric exercise. Subjects performed 2 sets of 50 passive arm curls with the dominant arm on an isokinetic dynamometer with a maximal eccentric muscle action superimposed every fourth passive repetition. One repetition maximum elbow flexion, upper arm circumference, relaxed elbow angle, blood serum cortisol, creatine kinase, lactate dehydrogenase, and perception of soreness questionnaires were collected prior to the exercise bout and daily thereafter for 5 days. RESULTS: Creatine kinase was significantly elevated from the baseline value in both groups, although the experimental compression test group showed decreased magnitude of creatine kinase elevation following the eccentric exercise. Compression sleeve use prevented loss of elbow motion, decreased perceived soreness, reduced swelling, and promoted recovery of force production. CONCLUSIONS: Results from this study underline the importance of compression in soft tissue injury management.

The effect of heavy resistance exercise on the circadian rhythm of salivary testosterone in men.

Circadian rhythms of serum testosterone concentrations in men have been shown, in general, to be highest in the morning and lowest in the evening. Thus, the purpose of this investigation was to determine the effects of acute resistance exercise upon the waking circadian rhythm of salivary testosterone over 2 days (with or without resistance exercise). The subjects included ten resistance-trained men (with at least 1 year of lifting experience) with the following characteristics [mean (SD)]: age 21.6 (1.1) years; height 177.8 (9.5) cm; body mass 80.5 (11.5) kg; percent body fat 7.9 (1.7)%. A matched, randomized, crossover study design was used such that each subject was tested under both the resistance exercise and control (no exercise) conditions. The resistance exercise protocol consisted of ten exercises performed for three sets of ten repetitions maximum with 2 min of rest between sets. Saliva sample 1 was collected at 0615 hours and resistance exercise began immediately afterwards at approximately 0620 hours, and sample 2 was collected at 0700 hours, which corresponded approximately to a mid-exercise (or control) time point. Saliva samples were then obtained every hour on the hour from 0800 hours until 2200 hours. No significant differences were observed between the exercise and resting conditions for salivary testosterone, with the exception of a significant decrease at 0700 hours during the resistance exercise protocol. The results of this investigation indicate that resistance exercise does not affect the circadian pattern of salivary testosterone secretion over a 16-h waking period in resistance-trained men.

Resistance training combined with bench-step aerobics enhances women's health profile.

PURPOSE: The purpose of this study was to investigate the comprehensive physiological alterations that take place during the combination of bench-step aerobics (BSA) and resistance exercise training. METHODS: Thirty-five healthy, active women were randomly assigned to one of four groups that either a) performed 25 min of BSA only (SA25); b) performed a combination of 25 min of BSA and a multiple-set upper and lower body resistance exercise program (SAR); c) performed 40 min of BSA only (SA40); or d) served as a control group (C), only performing activities of daily living. Direct assessments for body composition, aerobic fitness, muscular strength, endurance, power, and cross-sectional area were performed 1 wk before and after 12 wk of training. RESULTS: All training groups significantly improved peak VO(2) (3.7 to 5.3 mL O(2).kg(-1).min(-1)), with the greatest improvement observed in the SAR group (P = 0.05). Significant reductions in preexercise heart rates (8-9 bpm) and body fat percent (5--6%) were observed in all training groups after training. Significant reductions in resting diastolic blood pressure were observed for the SAR and SA40 groups (6.7 and 5.8 mm Hg, respectively). Muscular strength and endurance only improved significantly in the SAR group (21 and 11% respectively). All groups demonstrated increased lower body power (11--14%), but only the SAR group significantly improved upper body power (32%). Thigh muscle cross-sectional areas measured via magnetic resonance imaging (MRI) increased primarily for the SAR group. CONCLUSION: BSA is an exercise modality effective for improving physical fitness and body composition in healthy women. The addition of resistance exercise appears to enhance the total fitness profile by improving muscular performances, muscle morphology, and cardiovascular fitness greater than from performing BSA alone. Therefore, the inclusion of both modalities to an exercise program is most effective for improving total body fitness and a woman's health profile.

Taste changes experienced by patients receiving chemotherapy.

PURPOSE/OBJECTIVES: To increase knowledge about the nature, frequency, and quality-of-life (QOL) effects associated with taste changes after chemotherapy. DESIGN: Cross-sectional, descriptive. SETTING: 11 outpatient urban and suburban oncology centers. SAMPLE: 284 adults who had received at least two chemotherapy cycles. METHODS: Patients completed a taste change questionnaire and the Functional Assessment of Cancer Therapy-General, and nurses collected demographic and disease-related information. Descriptive statistics, Spearman correlations, chi-square, Mann-Whitney, and Kruskal-Wallis one-way analysis of variance were calculated. FINDINGS: Taste changes were frequent and at least moderately severe for many patients, who often reported dry mouth, decreased appetite, nausea, and vomiting. Cisplatin and doxorubicin were the agents most likely to be related to severe taste changes and to have caused greater distress from taste changes, which also were associated with decreased QOL. Oncology nurses and physicians rarely discussed taste changes with patients, who often tried changing the ways they seasoned their food. CONCLUSIONS: Taste changes are a frequent and significant problem for patients receiving chemotherapy and have negative effects on patients' QOL. Oncology nurses and physicians typically do not offer self-management suggestions to patients. IMPLICATIONS FOR NURSING RESEARCH AND PRACTICE: Repeated-measures research may provide a clearer understanding of chemotherapy-associated taste changes over time. Studies to examine strategies suggested from this and other research as well as clinical literature may determine which self-care interventions are most useful. Nurses should inform patients that taste changes may occur following chemotherapy, provide self-management information, and assess for related problems that could increase chemotherapy morbidity.

Breast and ovarian cancer: genetic update and implications for nursing.

Advances in genetics are changing approaches to detecting and treating breast and ovarian cancer. Scientific breakthroughs and thus implications for clinical care and patient education are essential areas of knowledge for all medical-surgical nurses. Future discoveries promise to change drastically the prevention and treatment of these diseases.

Main renal vein invasion by a transitional cell carcinoma of the renal pelvis: documentation with CT.

Invasion of the main renal vein by transitional cell cancer of the renal pelvis is an infrequently reported event. No accurate clinical frequency of this phenomenon is available. Extensive invasion of the renal parenchyma by the tumor usually is present by the time it presents in the renal vein. This article represents but the second documenting main renal vein involvement depicted with computerized tomography in a patient with carcinoma of the renal pelvis.

Long-term central venous catheters: issues for care.

Long-term central venous catheters allow the safe administration of chemotherapy, blood and blood products, total parenteral nutrition, fluids, and other medications. Despite their benefits, the risk of certain complications (e.g., fibrin sleeve and mural thrombus formation, infection, catheter occlusion, extravasation, and catheter malposition) exist for every person who has a catheter. Thus, preventative measures, recognition of early signs and symptoms of complications, and adequate care of utmost importance.

Correlates of fatigue in people with breast or lung cancer.

Fatigue is regarded as a universal and unavoidable side effect of cancer therapy, yet its epidemiology and prevalence in populations of people with cancer have not been well-documented. Using the conceptual framework of Piper, et al., this study examined and described the perception and manifestations of fatigue and its physiological, biochemical, and behavioral correlates. A convenience sample (N = 77) of people with lung (n = 33) or breast cancer (n = 44) completed several instruments: a brief questionnaire, the Rhoten Fatigue Scale, a visual analogue scale (VAS), the Rhoten Fatigue Checklist, and the shortened version of the Profile of Mood States (POMS). Data on other factors thought to influence fatigue were collected via medical record audit. Seventy-five of 76 people (99%) completing the VAS experienced some level of fatigue. Significant correlates of fatigue included level of pain and POMS scores. Preliminary findings suggest that fatigue is a common problem with a complex etiology and that nurses must consider potential contributing factors when assessing fatigue and its impact on the individual.

Collaborative research under the unification model.

The research role of the clinical nurse specialist is often the most difficult to implement. At the masters level, efforts are generally directed at utilization and evaluation of research more than design and implementation. Collaboration between several investigators, however, is an efficient and effective method of pooling the resources of a variety of researchers, allowing the actualization of all aspects of the research process. A collaborative effort to look at the clinical problem of fatigue was undertaken by a group of masters-prepared oncology nurses. Strategies for effective collaboration are outlined. Issues related to gaining group commitment and to delineating roles at the onset, voluntary participation, and timely communication are discussed. A realistic timetable and regular informal meetings helped to sustain the momentum of the study. All members were able to contribute a part of the completed project and to experience the professional and personal satisfaction of "owning" a research project from start to finish.

Advances in venous access devices and nursing management strategies.

VADs are indicated for many persons who require reliable long-term venous access. Nontunneled, tunneled, and venous access ports are constructed of silicone or polyurethane, the most biocompatible materials identified thus far. These devices are inserted in a similar fashion and are extremely versatile. Although VADs represent a major advance in catheter technology, they are not without problems. The most serious and frequently reported complications include infection, thrombosis, and extravasation. Catheter occlusions are another frequent problem, and may be caused by clotted blood or precipitated drug within the catheter. Nursing care centers on prevention and intervention to remove the occlusion. Catheter-related infections may occur at one or more points along the catheter. The most serious are those occurring in the tunnel or as a result of a mural or catheter-tip thrombus. Normal skin flora are most commonly cultured with catheter-related infections. These organisms may be introduced into the body through the catheter hub or less often by migrating along the external catheter. Infections differ in their severity, prognosis, and treatment. Actions to minimize risk (scrupulous care and patient teaching), prompt recognition, and appropriate interventions are crucial. Thrombotic events include fibrin sheaths, patchy thrombotic plaques on the cannulated venous intima, and totally occlusive mural thromboses. Problems associated with these can range from withdrawal occlusion to obstruction of the great vessels and symptoms of superior vena cava syndrome. Mural thrombosis, which probably occurs more frequently than previously suspected, is the most significant risk factor for infection and may also potentiate extravasation. Prompt initiation of therapy will resolve symptoms and maintain the functioning of the catheter. Extravasation can result in transient discomfort or major tissue damage, pain, and functional loss. Needle dislodgment from ports is the most frequent cause. Adequate stabilization of needles and use of nonsiliconized needles are recommended to decrease this risk. Thrombosis at the catheter tip with back tracking of infusate out of the vein to subcutaneous tissues is the second most frequent cause of extravasation and has been reported with tunneled catheters as well as ports. It should be noted that catheter-tip displacement and catheter damage infrequently lead to extravasation. When extravasation is suspected, the infusion is stopped, and the nurse notifies the physician so diagnostic procedures and treatment can be initiated. Other complications occur infrequently but may contribute to patient discomfort, morbidity, and mortality. These include phlebitis, which resolves with conservative management in most instances, and pneumothorax, which occurs in a small percentage of patients within a short period after catheter placement.(ABSTRACT TRUNCATED AT 400 WORDS)

Managing chemotherapy-related nausea and vomiting: the state of the art.

The consequences of inadequately controlled chemotherapy-related nausea and vomiting range from minor discomfort to dose-limiting toxicity. Physical complications may occur secondary to protracted nausea and emesis. Furthermore, patient discomfort may be reflected in altered quality of life or noncompliance with therapy. As a primary caregiver, the nurse takes an active role in collaborating with the physician to prevent and/or minimize these side effects and their sequelae. An understanding of the patterns, mechanisms, and risk of chemotherapy-related nausea and vomiting is crucial to providing optimal patient care. Concepts of drug therapy are emphasized as the cornerstone of antiemetic management.