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1.
Heather Draper 《Bioethics》2000,14(2):120-133
People who suffer from eating disorders often have to be treated against their will, perhaps by being detained, perhaps by being forced to eat. In this paper it is argued that whilst forcing compliance is generally acceptable, there may be circumstances under which a sufferer's refusal of consent to treatment should be respected. This argument will hinge upon whether someone in the grip of an eating disorder can actually make competent decisions about their quality of life. If so, then the decision to refuse therapy may be on a par with other decisions to refuse life-prolonging therapy made by sufferers of debilitating chronic, or acute onset terminal illness. In such cases, palliation might justifiably replace aggressive therapy. The argument will also draw heavily on the distinction between competent refusal of therapy and passive euthanasia, and the distinction between incompetent and irrational decisions. Both distinctions will then be applied to decisions to refuse food. The extent to which sufferers from anorexia nervosa can be categorised as either incompetent or irrational will be examined. It is against this background that it will be argued that at least some of those who suffer from eating disorders should have their refusals respected, even if they may die as a result.  相似文献   

2.
This paper addresses current issues regarding the diagnosis and management of binge eating disorder (BED). Controversies in diagnosis include the lack of empirically validated criteria, the lack of a universally recognized operational definition of a "binge episode", and the lack of age-appropriate assessment instruments in light of growing reports of BED among children and adolescents. For adults with BED, several pharmacological and behavioral treatments have shown promise in reducing binge frequency and related psychological symptoms of disordered eating (i.e., disinhibition, hunger, depressed mood). Second-generation antidepressants and cognitive behavioral therapy are among the most widely studied treatments. However, no behavioral interventions have demonstrated efficacy with respect to weight loss (which is a critical concern for many BED sufferers who are overweight). Furthermore, randomized controlled trials for BED have been plagued by high drop out and placebo response rates, as well as by insufficient follow-up after active treatment ends to determine long-term outcomes. Therefore, the long-term utility of the various intervention strategies studied thus far remains unclear. More research is needed on innovative medications and behavioral treatments that explore novel modalities to reduce the subjectively reinforcing properties of binge eating. In addition, expanded use of information technologies may be particularly instrumental in the treatment of patients who experience marked shame, denial, and interpersonal deficits, or who face limited access to specialty care. Ultimately, examining BED within the broader context of the current obesity epidemic will be an important area of study.  相似文献   

3.
Cain WS  Schmidt R 《Chemical senses》2002,27(5):425-433
A study of 30 young adults (15 males, 15 females), screened to have normal olfaction, measured detection of the flavor of glutaraldehyde, a biocide that could occur in disinfected potable water. Over the range of interest, up to 100 p.p.m., flavor derived from olfactory stimulation. Higher concentrations would cause oral irritation. Fourteen subjects failed to detect the glutaraldehyde in the first of four sessions of testing. Eight of the 14 (seven males, one female) continued to exhibit the anosmia throughout testing. The other six (one male, five females) began to detect the material in session two and exhibited increasing sensitivity over sessions two to four. Their average sensitivity never reached that of the 16 subjects who evinced no anosmia and who also improved their performance over sessions. The combined group of 22 could detect 17 p.p.m. Less thorough testing would have yielded much higher values. Specific anosmia for this dialdehyde has precedence in anosmia for various monoaldehydes, most notably isobutyraldehyde. The positive influence of experience with a material on detection has been found previously, most intriguingly by Wysocki and colleagues, who showed that experience could differentially induce sensitivity to the odorant androstenone and suggested that the phenomenon might occur for other compounds. Glutaraldehyde appears to be one, perhaps of many.  相似文献   

4.
Many individuals restrict their food intake to prevent weight gain. This restriction has both homeostatic and hedonic effects but their relative contribution is currently unclear. To isolate hedonic effects of food restriction, we exposed regular chocolate eaters to one week of chocolate deprivation but otherwise regular eating. Before and after this hedonic deprivation, participants viewed images of chocolate and images of high-calorie but non-chocolate containing foods, while experiential, behavioral and eyeblink startle responses were measured. Compared to satiety, hedonic deprivation triggered increased chocolate wanting, liking, and chocolate consumption but also feelings of frustration and startle potentiation during the intertrial intervals. Deprivation was further characterized by startle inhibition during both chocolate and food images relative to the intertrial intervals. Individuals who responded with frustration to the manipulation and those who scored high on a questionnaire of impulsivity showed more relative startle inhibition. The results reveal the profound effects of hedonic deprivation on experiential, behavioral and attentional/appetitive response systems and underscore the role of individual differences and state variables for startle modulation. Implications for dieting research and practice as well as for eating and weight disorders are discussed.  相似文献   

5.
Summary Ring chromosome 16 was found in a 33-year-old woman with mental, motor, and growth defects. Apart from a low percentage of monosomy 16 cell lines, the patient appears to have virtually all of the normal chromosome 16 genetic material at the microscopic level. Her impressive problems highlight the limitation of our ability to detect small deletions and the profound importance of the integrity of chromosome 16 in normal human development.  相似文献   

6.
In an attempt to investigate the relative importance of endogenous and exogenous factors in determining food intake, 14 healthy subjects were studied while living in an Isolation Unit (where external time cues were absent) for eighteen 28 h "days" (equal to 21 solar days). The subjects were free to spend their waking time as they chose, and they had a free choice of what they ate and when they ate it. The only restrictions were that no naps were allowed in the "daytime," that some time was required to perform a variety of tests at regular intervals throughout the 18.67 h waking periods, and that any food preparation had to be performed by the subjects themselves. Core (rectal) temperature and activity were monitored throughout, and the subjects answered a questionnaire on their eating habits at 3 h intervals during the waking periods. The questionnaire investigated reasons for eating or not eating a meal during the previous 3 h and, if a meal had been eaten, its type, the factors influencing that choice, and the subjects' subjective responses (hunger before, enjoyment during, and satiety after) to it. The results were analyzed (two-way ANOVA) in terms of both the imposed day length (the exogenous component) and the free-running period of the temperature rhythm (the endogenous component). Results indicated that by far the main reason for eating/not eating was hunger/lack of hunger rather than factors such as food availability and time-pressure. There were statistically significant effects of time within the imposed waking periods upon the type of meal eaten--"breakfast" tending to be a snack, "lunch" a small hot meal, and the "evening meal" a large hot meal. Hot meals (whether small or large) were associated with more hunger before the meal, more enjoyment of the meal, and a greater degree of satiety afterward than were cold meals. These effects suggest that the individuals adjusted their eating habits to fit in with the imposed wake times. By contrast, the effect of circadian phase upon food intake, the type of meal eaten, and subjective responses to the meal was much weaker, and either statistically nonsignificant (P > 0.10) or only marginally so (0.10 > P > 0.05). For example, a large hot meal was chosen as readily for an "evening meal," and subjective responses to it were the same, at whatever circadian phase it was eaten. We conclude that food intake during forced desynchronization is dominated by the waking schedule rather than by circadian influences; some of the implications of these findings when eating habits and the metabolism of food are concerned, particularly in night workers, are considered briefly.  相似文献   

7.
In an attempt to investigate the relative importance of endogenous and exogenous factors in determining food intake, 14 healthy subjects were studied while living in an Isolation Unit (where external time cues were absent) for eighteen 28 h “days” (equal to 21 solar days). The subjects were free to spend their waking time as they chose, and they had a free choice of what they ate and when they ate it. The only restrictions were that no naps were allowed in the “daytime,” that some time was required to perform a variety of tests at regular intervals throughout the 18.67 h waking periods, and that any food preparation had to be performed by the subjects themselves. Core (rectal) temperature and activity were monitored throughout, and the subjects answered a questionnaire on their eating habits at 3 h intervals during the waking periods. The questionnaire investigated reasons for eating or not eating a meal during the previous 3 h and, if a meal had been eaten, its type, the factors influencing that choice, and the subjects’ subjective responses (hunger before, enjoyment during, and satiety after) to it. The results were analyzed (two-way ANOVA) in terms of both the imposed day length (the exogenous component) and the free-running period of the temperature rhythm (the endogenous component). Results indicated that by far the main reason for eating/not eating was hunger/lack of hunger rather than factors such as food availability and time-pressure. There were statistically significant effects of time within the imposed waking periods upon the type of meal eaten—“breakfast” tending to be a snack, “lunch” a small hot meal, and the “evening meal” a large hot meal. Hot meals (whether small or large) were associated with more hunger before the meal, more enjoyment of the meal, and a greater degree of satiety afterward than were cold meals. These effects suggest that the individuals adjusted their eating habits to fit in with the imposed wake times. By contrast, the effect of circadian phase upon food intake, the type of meal eaten, and subjective responses to the meal was much weaker, and either statistically nonsignificant (P > 0.10) or only marginally so (0.10 > P > 0.05). For example, a large hot meal was chosen as readily for an “evening meal,” and subjective responses to it were the same, at whatever circadian phase it was eaten. We conclude that food intake during forced desynchronization is dominated by the waking schedule rather than by circadian influences; some of the implications of these findings when eating habits and the metabolism of food are concerned, particularly in night workers, are considered briefly.  相似文献   

8.
Food consumption in stressful situations vary as a function of individual difference factors (e.g., emotional vs. non-emotional eating), and may be related to hormonal responses elicited by the stressful event. These hormonal responses may be tied to specific emotions elicited by the stressful event. The present investigation examined the emotional and hormonal (cortisol, ghrelin) responses of high and low emotional eaters following a laboratory stressor (Trier Social Stress Test; TSST). Women (n = 48) either high or low in emotional eating status were tested in a TSST or served as controls during which blood samples were taken for analysis of cortisol and ghrelin, both of which have been implicated in eating and in response to stressors. The TSST promoted elevated cortisol levels, being somewhat more pronounced in emotional than in non-emotional eaters. Both shame and anger were provoked by the TSST, and although both these emotions were correlated with cortisol levels, only anger significantly mediated the relationship between the stressor and cortisol levels. As well, baseline ghrelin levels in low emotional eaters exceeded that of high emotional eaters, and increased moderately in response to the stressor situation, irrespective of emotional eating status. Interestingly, when provided with food, ghrelin levels declined in the non-emotional eaters, but not in emotional eaters. The possibility is offered that the lack of a decline of ghrelin in emotional eaters may sustain eating in these individuals.  相似文献   

9.
Several species of lizards respond to chemicals from sympatric lizard‐eating snakes with increased tongue‐extrusion rates. These substances also elicit antipredator behavior indicating that they have important ecological functions and the resulting behavior can have serious implications for individual fitness of lizards. However, the source and type of snake chemical cues that elicit these behavioral changes in lizards have yet to be determined. We tested the ability of adult desert iguanas (Dipsosaurus dorsalis) to detect and identify a potential predator by exposing them to lipids extracted from shed snakeskins. Lipids were extracted from cast skins of a known lizard‐eating snake, the California kingsnake (Lampropeltis getula californiae), using chloroform and methanol. Test subjects were presented with skin lipids as well as clean, pungent, and chloroform controls on cotton‐tipped applicators in random order. Desert iguanas directed significantly more tongue extrusions toward applicators bearing snakeskin lipids when compared with controls. In addition, overall tongue‐extrusion frequency increased following exposure to lipids during the 5‐min trials. Desert iguanas clearly detected snakeskin lipids, but this stimulus failed to elicit changes in body posture and movement patterns previously observed in experiments using chemical cues from live snakes. Increased tongue flicking by lizards in response to snakeskin lipids may represent a generalized response to this class of chemicals. Additional potential sources of chemicals used in the detection of lizard‐eating snakes are discussed.  相似文献   

10.
Type I and III interferons (IFNs) of the innate immune system belong to a polygenic family, however the individual subtype mediators of the antiviral response in viral infections have been hindered by a lack of reagents. Evaluation studies using different IFN subtypes have distinguished distinct protein properties with different efficacies towards different viruses, opening promising avenues for immunotherapy. This review largely focuses on the application of IFN-α/β and IFN-λ therapies for viral infections, influenza, herpes, HIV and hepatitis. Such IFN subtype therapies may help to cure patients with virus infections where no vaccine exists. The ability of cell types to secrete a number of IFN subtypes from a multi-gene family may be an intuitive counterattack on viruses that evade IFN subtype responses. Hence, clinical use of virus-targeted IFN subtypes may restore antiviral immunity in viral infections. Accumulating evidence suggests that individual IFN subtypes have differential efficacies in selectively activating immune cell subsets to enhance antiviral immune responses leading to production of sustained B and T cell memory. Cytokine therapy can augment innate immunity leading to clearance of acute virus infections but such treatments may have limited effects on chronic virus infections that establish lifelong latency. Therefore, exploiting individual IFN subtypes to select those with the ability to sculpt protective responses as well as reinstating those targeted by viral evasion mechanisms may inform development of improved antiviral therapy.  相似文献   

11.
Living at high altitude is one of the most difficult challenges that humans had to cope with during their evolution. Whereas several genomic studies have revealed some of the genetic bases of adaptations in Tibetan, Andean, and Ethiopian populations, relatively little evidence of convergent evolution to altitude in different continents has accumulated. This lack of evidence can be due to truly different evolutionary responses, but it can also be due to the low power of former studies that have mainly focused on populations from a single geographical region or performed separate analyses on multiple pairs of populations to avoid problems linked to shared histories between some populations. We introduce here a hierarchical Bayesian method to detect local adaptation that can deal with complex demographic histories. Our method can identify selection occurring at different scales, as well as convergent adaptation in different regions. We apply our approach to the analysis of a large SNP data set from low- and high-altitude human populations from America and Asia. The simultaneous analysis of these two geographic areas allows us to identify several candidate genome regions for altitudinal selection, and we show that convergent evolution among continents has been quite common. In addition to identifying several genes and biological processes involved in high-altitude adaptation, we identify two specific biological pathways that could have evolved in both continents to counter toxic effects induced by hypoxia.  相似文献   

12.
Twenty-eight day-old male rats were subjected to: Blinding-olfactory bulbectomy, Blinding-peripheral anosmia, Blinding-accessory olfactory bulbectomy and Blinding-sham olfactory operation. A set of rats remained intact. Six weeks later, their pituitary-gonads-accessory sex organs were studied. Bulbectomy as well as peripheral anosmia exaggerated the antigonadal effects of blindness, while the accessory olfactory system impairment did not. It is suggested that olfactory bulbectomy potentiation of the antigonadal effects of light deprivation is due to a lack of sensory function rather than to bulbectomy itself and that the accessory olfactory system which is involved in the priming pheromonal effects does not play any role in the inhibition of the antigonadal effects of blindness.  相似文献   

13.
Ab is a crucial component of protective immunity to infection, but Ab responses do not proceed normally when defects occur in a protein called signaling lymphocytic activation molecule-associated protein (SAP). To explain this Ab defect, we analyzed B cell and plasma cell responses under conditions of SAP deficiency. Our results demonstrate that SAP-deficient (SAP knockout (KO)) mice have a profound CD4 T cell-intrinsic defect in generating Ag-specific plasma cells following challenge with model Ags or influenza virus, resulting in low Ag-specific Ab titers. We also show that SAP is required in CD4 T cells for normal division and expansion of B cells. These B cell and plasma cell defects were observed during the expansion phase of the primary immune response, indicating early defects in Th cell activity. In fact, additional experiments revealed a nearly complete lack of T cell help for B cells in SAP KO mice. Our work suggests that the ability of SAP to promote T-dependent humoral immune responses is important for antiviral immunity because mice lacking SAP are unable to prevent high dose secondary influenza infection, and because passive transfer of IgG in immune serum from wild-type, but not SAP KO mice can protect mice from an otherwise lethal influenza infection. Overall, our results demonstrate that SAP is required in CD4 T cells for their ability to help B cell responses and promote influenza-specific immunity.  相似文献   

14.
Specific anosmia is a term that describes an inability to perceive a particular odorant in the context of an otherwise normal olfactory acuity. The most common example, for the odor of androstenone, has been ascribed a prevalence ranging from 2 to 45%. In two experiments we sought to determine whether this wide range could be explained by the difference in steroid concentrations used, and by the degree to which the trigeminal system contributes to perception of androstenone. Experiment 1 demonstrated that high concentrations of androstenone stimulated the trigeminal system, as indicated by electrophysiological recordings. Experiment 2 demonstrated that conscious detection of androstenone is possible based solely on the trigeminal system. Interestingly, detection seems to interact with olfactory acuity in that subjects with a low olfactory sensitivity to androstenone were better able to detect its trigeminal component. The agreement between conscious experience and behavioral discrimination was not well calibrated, in that subjects demonstrated a clear overconfidence in their abilities. Altogether, the current study suggests that androstenone is an odorant that produces a concentration-dependent degree of trigeminal stimulation. This trigeminal component explains the diversity of the reported prevalence of specific anosmia for androstenone and might have implications on future use of specific anosmia as a tool to understand odor processing.  相似文献   

15.
Natural suppressor activity is defined as the ability of unstimulated effector cells to suppress responses of lymphoid cells to antigenic and mitogenic stimuli in an MHC unrestricted manner. We have described natural suppressor cells in bone marrow exerting such a function through a suppressor factor termed BDSF. In this report we demonstrate the ability of BDSF to regulate the in vitro EBV- and PWM-induced production of both IgM and IgM rheumatoid factor antibodies of lymphoid cells obtained from normal individuals and those with rheumatoid arthritis. BDSF therefore may play a role in the normal BM microenvironment suppressing primary IgM antibody responses. Since autoantibody responses are similarly suppressed, functional alteration or lack of BDSF may be responsible for the emergence of autoantibody-producing cells in bone marrow during certain autoimmune states.  相似文献   

16.
We discuss current information on the ability of extracts and isolated metabolites from mushrooms to modulate immune responses. This can result in a more enhanced innate and acquired disease resistance. The major immunomodulating effects of these active substances derived from mushrooms include mitogenicity and activation of immune effector cells, such as lymphocytes, macrophages, and natural killer cells, resulting in the production of cytokines, including interleukins (ILs), tumor necrosis factor alpha (TNF)-alpha, and interferon gamma (INF)-gamma. In particular, the ability of selective mushroom extracts to modulate the differentiation capacity of CD4(+) T cells to mature into T(H)1 and/or T(H)2 subsets will be discussed. As a consequence these extracts will have profound effects in particular diseases, like chronic autoimmune T(H)1-mediated or allergic T(H)2-mediated diseases. Immunosuppressive effects by mushroom components have also been observed. The therapeutic effects of mushrooms, such as anticancer activity, suppression of autoimmune diseases, and allergy have been associated with their immunomodulating effects. However, further studies are needed to determine the molecular mechanisms of the immunomodulating effects of mushrooms metabolites both individually and in complex mixtures, for example, extracts.  相似文献   

17.
Fish provide a wonderful opportunity to explore processes that shape and select cognitive ability. In this presentation, I will illustrate three aspects of work that my colleagues and I have used to investigate fish learning and memory over the last decade. First, I will discuss how comparing different populations sampled from contrasting habitats allows differences in cognitive ability to be related to the evolutionary ecology of the fish. I will use examples that have investigated how differences in learning ability between populations of the same species can arise. Here, the examples will be taken from the ubiquitous three‐spined stickleback, and a Panamanian poecilid, Brachyraphis .
The second approach has used fish cognition as a tool to quantify behaviour to enable assessment of different aspects of fish welfare. For example, the recent work investigating pain perception in trout required the use of a learning task to quantify how fish behaviour was modified after noxious stimulation. Ways in which these, and similar, processes can be used in future studies of fish welfare will be discussed.
The final part of the presentation will consider recent work that addresses the problems of releasing hatchery‐reared fish for restocking purposes. Although a common practice, most of the hatchery‐reared fish die shortly after they are released. Much of the observed mortality apparently stems from the fishes' inexperience with a variable environment. Experiments with juvenile cod and brown trout suggest that both age, and the early rearing environment, have profound effects on fish learning and behaviour. I will discuss how simple modifications to current rearing practices may have large beneficial effects on the post‐release survival of hatchery‐reared fish.  相似文献   

18.
Intranasal application of zinc gluconate has commonly been used to treat the common cold. The safety of this treatment, however, has come into question recently. In addition to a United States recall of a homeopathic product that contains zinc gluconate, abundant literature reports cytotoxic effects of zinc on the olfactory epithelium. Additional research suggests that divalent cations (such as zinc) can block ion channels that facilitate the transduction of odors into electrical signals on the olfactory epithelium. The purpose of the current study was 2-fold: to confirm whether zinc gluconate causes anosmia and to reveal whether any other divalent cationic compounds produce a similar effect. Groups of mice underwent a buried food-pellet test to gauge olfactory function and then were nasally irrigated with 1 of 3 divalent cationic compounds. When tested after treatment, mice irrigated with zinc gluconate and copper gluconate experienced a marked increase in food-finding time, indicating that they had lost their ability to smell a hidden food source. Control mice irrigated with saline had a significantly lower increase in times. These results confirm that zinc gluconate can cause anosmia and reveal that multiple divalent cations can negatively affect olfaction.  相似文献   

19.
Neuronal function depends on the properties of the synaptic inputs the neuron receive and on its intrinsic responsive properties. However, the conditions for synaptic integration and activation of intrinsic responses may to a large extent depend on the level of background synaptic input. In this respect, the deep cerebellar nuclear (DCN) neurons are of particular interest: they feature a massive background synaptic input and an intrinsic, postinhibitory rebound depolarization with profound effects on the synaptic integration. Using in vivo whole cell patch clamp recordings from DCN cells in the cat, we find that the background of Purkinje cell input provides a tonic inhibitory synaptic noise in the DCN cell. Under these conditions, individual Purkinje cells appear to have a near negligible influence on the DCN cell and clear-cut rebounds are difficult to induce. Peripheral input that drives the simple spike output of the afferent PCs to the DCN cell generates a relatively strong DCN cell inhibition, but do not induce rebounds. In contrast, synchronized climbing fiber activation, which leads to a synchronized input from a large number of Purkinje cells, can induce profound rebound responses. In light of what is known about climbing fiber activation under behaviour, the present findings suggest that DCN cell rebound responses may be an unusual event. Our results also suggest that cortical modulation of DCN cell output require a substantial co-modulation of a large proportion of the PCs that innervate the cell, which is a possible rationale for the existence of the cerebellar microcomplex.  相似文献   

20.
A questionnaire was designed to assess the following: why working people chose to eat or not to eat at a particular time of day; the factors that influenced the type of food eaten; and subjective responses to the meal (hunger before, enjoyment during, satiety afterward). Self-assessments were done every 3 h during a typical week containing work and rest days, by one group of 50 day workers and another group of 43 night workers. During the night work hours compared to rest days, night workers evidenced a significantly altered food intake, with a greater frequency of cold rather than hot food (p < 0.001). The type and frequency of meals were influenced significantly more (p < 0.05) by habit and time availability and less by appetite. This pattern continued into the hours immediately after the night shift had ended. In day workers food intake during work hours, compared to rest days, was also influenced significantly more often (p < 0.05) by time availability than hunger, but less so than with night workers. Moreover, day workers were less dependent than night workers upon snacks (p = 0.01), and any significant differences from rest days did not continue beyond work hours. Not only did night workers change their eating habits during work days more than did day workers but also they looked forward to their meals significantly less (p < 0.001) and felt more bloated after consuming them (p < 0.05), such effects being present to some extent during their rest days also. These findings have clear implications for measures designed to ease eating problems that are commonly problematic in night workers.  相似文献   

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