Species traits and climate velocity explain geographic range shifts in an ocean-warming hotspot

Species' ranges are shifting globally in response to climate warming, with substantial variability among taxa, even within regions. Relationships between range dynamics and intrinsic species traits may be particularly apparent in the ocean, where temperature more directly shapes species' distributions. Here, we test for a role of species traits and climate velocity in driving range extensions in the ocean-warming hotspot of southeast Australia. Climate velocity explained some variation in range shifts, however, including species traits more than doubled the variation explained. Swimming ability, omnivory and latitudinal range size all had positive relationships with range extension rate, supporting hypotheses that increased dispersal capacity and ecological generalism promote extensions. We find independent support for the hypothesis that species with narrow latitudinal ranges are limited by factors other than climate. Our findings suggest that small-ranging species are in double jeopardy, with limited ability to escape warming and greater intrinsic vulnerability to stochastic disturbances.

Trial of pyrethroid impregnated bednets in an area of Tanzania holoendemic for malaria. Part 2. Effects on the malaria vector population

The malaria vector population consisted mainly of Anopheles gambiae s.s. with a small contribution from An. funestus and An. rivulorum. The mosquitoes coming to bite in bedrooms were monitored with light traps set beside untreated bednets. When impregnated bednets were provided for all the other beds in a village the Anopheles populations declined but the Culex quinquefasciatus populations were unaffected. The survival of An. gambiae (as measured by the mean number of ovarian dilatations) and the sporozoite rate declined following introduction of the nets and the estimated sporozoite inoculation rates into people not under their nets declined by more than 90%. The net introductions caused sharp declines in the number of mosquitoes resting indoors, but the evidence was inconclusive regarding diversion to outdoor resting, animal biting, earlier biting or outdoor biting. DDT spraying greatly reduced the Anopheles populations.

The 6-min walk test (6MW) as an efficacy endpoint in pulmonary arterial hypertension clinical trials: Demonstration of a ceiling effect

BACKGROUND

PAH trials traditionally use 6MW as the primary endpoint. Concerns regarding a "ceiling effect" masking efficacy have led to exclusion of patients with milder disease from most trials (BL 6MW>450 m). STRIDE I evaluated the selective endothelin A receptor antagonist, sitaxsentan (SITAX), in a 12-week randomized, double-blind, trial (178 patients) employing placebo (PBO), 100 mg or 300 mg SITAX orally once daily in PAH and included patients with NYHA class II, congenital heart disease and a BL 6MW>450 m, groups often excluded from previous trials.

METHODS

We analyzed 6MW effects For All Pts (intention-to treat) and those meeting Traditional enrollment criteria, defined as patients with NYHA class III or IV and 6MW< or =450 m at BL with idiopathic PAH or PAH related to connective tissue disease. The 100 mg and 300 mg SITAX arms are pooled based on similar treatment effects on 6MW.

CONCLUSION

Existence of a "ceiling effect" is supported by these data. The magnitude of the treatment effect and statistical power when using 6MW as the endpoint. Comparisons between PAH trials that do not adjust for the effects of differing enrollment criteria require caution.

A Standardised Vocabulary for Identifying Benthic Biota and Substrata from Underwater Imagery: The CATAMI Classification Scheme

Imagery collected by still and video cameras is an increasingly important tool for minimal impact, repeatable observations in the marine environment. Data generated from imagery includes identification, annotation and quantification of biological subjects and environmental features within an image. To be long-lived and useful beyond their project-specific initial purpose, and to maximize their utility across studies and disciplines, marine imagery data should use a standardised vocabulary of defined terms. This would enable the compilation of regional, national and/or global data sets from multiple sources, contributing to broad-scale management studies and development of automated annotation algorithms. The classification scheme developed under the Collaborative and Automated Tools for Analysis of Marine Imagery (CATAMI) project provides such a vocabulary. The CATAMI classification scheme introduces Australian-wide acknowledged, standardised terminology for annotating benthic substrates and biota in marine imagery. It combines coarse-level taxonomy and morphology, and is a flexible, hierarchical classification that bridges the gap between habitat/biotope characterisation and taxonomy, acknowledging limitations when describing biological taxa through imagery. It is fully described, documented, and maintained through curated online databases, and can be applied across benthic image collection methods, annotation platforms and scoring methods. Following release in 2013, the CATAMI classification scheme was taken up by a wide variety of users, including government, academia and industry. This rapid acceptance highlights the scheme's utility and the potential to facilitate broad-scale multidisciplinary studies of marine ecosystems when applied globally. Here we present the CATAMI classification scheme, describe its conception and features, and discuss its utility and the opportunities as well as challenges arising from its use.

The effect of botulinum toxin A on gastrocnemius length: magnitude and duration of response

Thirty-nine ambulant children (22 with hemiplegia, 17 with diplegia) with spastic cerebral palsy receiving isolated gastrocnemius muscle injection with botulinum toxin A were studied prospectively. The children had a mean age of 6 years (range 3 to 13 years). Measurement of gastrocnemius muscle length was used to estimate the dynamic component of each child's spasticity and to quantify the response. There was a strong correlation between the dynamic component of spasticity before injection and the corresponding magnitude of the response after injection. Children undergoing repeated injections showed similar correlations. A strong correlation was found between the duration of response and the dynamic component. Children with hemiplegia showed twice the duration for a given dynamic component compared with those with diplegia when injected with the same total dose per unit body weight. Long-term lengthening did not occur for the cohort, although some patients showed a response at a 12-month follow-up. By delaying shortening, the injections may have a role in delaying the need for surgery. Injections were well tolerated with few side effects.

Plant based insect repellent and insecticide treated bed nets to protect against malaria in areas of early evening biting vectors: double blind randomised placebo controlled clinical trial in the Bolivian Amazon

OBJECTIVE

To determine the effectiveness in reducing malaria of combining an insect repellent with insecticide treated bed nets compared with the nets alone in an area where vector mosquitoes feed in the early evening.

DESIGN

A double blind, placebo controlled cluster-randomised clinical study.

SETTING

Rural villages and peri-urban districts in the Bolivian Amazon.

PARTICIPANTS

4008 individuals in 860 households.

INTERVENTIONS

All individuals slept under treated nets; one group also used a plant based insect repellent each evening, a second group used placebo.

MAIN OUTCOME MEASURE

Episodes of Plasmodium falciparum or P vivax malaria confirmed by rapid diagnostic test or blood slide, respectively.

RESULTS

We analysed 15,174 person months at risk and found a highly significant 80% reduction in episodes of P vivax in the group that used treated nets and repellent (incidence rate ratio 0.20, 95% confidence interval 0.11 to 0.38, P<0.001). Numbers of P falciparum cases during the study were small and, after adjustment for age, an 82% protective effect was observed, although this was not significant (0.18, 0.02 to 1.40, P=0.10). Reported episodes of fever with any cause were reduced by 58% in the group that used repellent (0.42, 0.31 to 0.56, P<0.001).

CONCLUSIONS

Insect repellents can provide protection against malaria. In areas where vectors feed in the early evening, effectiveness of treated nets can be significantly increased by using repellent between dusk and bedtime. This has important implications in malaria vector control programmes outside Africa and shows that the combined use of treated nets and insect repellents, as advocated for most tourists travelling to high risk areas, is fully justified.

REGISTRATION

NCT 00144716.

Guidelines for the prevention of central venous catheter-related blood stream infections with prostanoid therapy for pulmonary arterial hypertension

Intravenous prostanoids are the backbone of therapy for advanced pulmonary arterial hypertension (PAH) and have improved long-term outcome and quality of life. Currently, two prostanoids are approved by the US Food and Drug administration for parenteral administration: epoprostenol (Flolan) and treprostinil (Remodulin). Chronic intravenous therapy presents considerable challenges for patients and caregivers who must learn sterile preparation of the medication, operation of the pump, and care of the central venous catheter. Patients are routinely counseled and advised regarding the risks of CR-BSIs and catheter care before central line insertion. Central line infections as well as bacteremia are well documented risks of chronic intravenous therapy and may significantly contribute to morbidity and mortality. Recent reports have suggested a possible increase in CR-BSI; therefore, the Scientific Leadership Council of the Pulmonary Hypertension Association decided to provide guidelines for good clinical practice regarding catheter care. Although data exits regarding patients with central venous catheters and the risk of blood stream infections in patients with cancer or other disorders, there is little data regarding the special needs of patients with pulmonary arterial hypertension requiring central venous access. These guidelines are extrapolated from the diverse body of literature regarding central venous catheter care.

Disparate LDL Phenotypic Classification among 4 Different Methods Assessing LDL Particle Characteristics

Background: Our study seeks to clarify the extent of differences in analytical results, from a clinical perspective, among 4 leading technologies currently used in clinical reference laboratories for the analysis of LDL subfractions: gradient gel electrophoresis (GGE), ultracentrifugation–vertical auto profile (VAP), nuclear magnetic resonance (NMR), and tube gel electrophoresis (TGE).

Methods: We collected 4 simultaneous blood samples from 40 persons (30 males and 10 females) to determine LDL subclasses in 4 different clinical reference laboratories using different methods for analysis. LDL subfractions were assessed according to LDL particle size and the results categorized according to LDL phenotype. We compared results obtained from the different technologies.

Results: We observed substantial heterogeneity of results and interpretations among the 4 methods. Complete agreement among methods with respect to LDL subclass phenotyping occurred in only 8% (n = 3) of the persons studied. NMR and GGE agreed most frequently at 70% (n = 28), whereas VAP matched least often.

Conclusions: As measurement of LDL subclasses becomes increasingly important, standardization of methods is needed. Variation among currently available methods renders them unreliable and limits their clinical usefulness.

The role of endogenous nitric oxide and platelet-activating factor in hypoxia-induced intestinal injury in rats

BACKGROUND/AIMS

Nitric oxide is an endothelium-derived relaxing factor that promotes capillary integrity, inhibits leukocyte adherence and activation, and scavenges oxygen radicals. Because these effects are important in experimental intestinal injury, we studied the role of NO inhibition on hypoxia-induced bowel necrosis in the rat and investigated the interaction between platelet-activating factor (PAF) and NO in this model.

METHODS

Sprague-Dawley rats were treated with either hypoxia, NO synthase inhibition (NG-methyl-L-arginine [LNMA] or NG-nitro-L-arginine methyl ester [L-NAME]), hypoxia+LNMA, hypoxia+LNMA+NO donors, or hypoxia+LNMA+PAF receptor inhibition. Evaluations included blood pressure, superior mesenteric artery blood flow, arterial blood gases, histological intestinal injury, intestinal myeloperoxidase activity, and intestinal PAF activity.

RESULTS

We found that hypoxia alone for 90 minutes (10% O2, partial O2 pressure = 45 mm Hg) or LNMA alone had no detrimental effects. However, hypoxia+LNMA together caused hypotension, metabolic acidosis, intestinal injury, increased intestinal myeloperoxidase activity, and elevated intestinal PAF concentrations that were prevented by exogenous L-arginine. Furthermore, the hypotension and intestinal injury was prevented by PAF receptor blockade.

CONCLUSIONS

We conclude that endogenous NO protects the intestine from hypoxia-induced inflammation and injury, and the balance between local PAF and NO modulates the outcome of hypoxia-stressed intestine.

Classification of 1H MR spectra of human brain neoplasms: the influence of preprocessing and computerized consensus diagnosis on classification accuracy

We study how classification accuracy can be improved when both different data preprocessing methods and computerized consensus diagnosis (CCD) are applied to 1H magnetic resonance (MR) spectra of astrocytomas, meningiomas, and epileptic brain tissue. The MR spectra (360 MHz, 37 degrees C) of tissue specimens (biopsies) from subjects with meningiomas (95; 26 cases), astrocytomas (74; 26 cases), and epilepsy (37; 8 cases) were preprocessed by several methods. Each data set was partitioned into training and validation sets. Robust classification was carried out via linear discriminant analysis (LDA), artificial neural nets (NN), and CCD, and the results were compared with histopathological diagnosis of the MR specimens. Normalization of the relevant spectral regions affects classification accuracy significantly. The spectra-based average three-class classification accuracies of LDA and NN increased from 81.7% (unnormalized data sets) to 89.9% (normalized). CCD increased the classification accuracy of the normalized sets to an average of 91.8%. CCD invariably decreases the fraction of unclassifiable spectra. The same trends prevail, with improved results, for case-based classification. Preprocessing the 1H MR spectra is essential for accurate and reliable classification of astrocytomas, meningiomas, and nontumorous epileptic brain tissue. CCD improves classification accuracy, with an attendant decrease in the fraction of unclassifiable spectra or cases.

Development of an antibiotic spectrum score based on veterans affairs culture and susceptibility data for the purpose of measuring antibiotic de-escalation: a modified Delphi approach

OBJECTIVE

Development of a numerical score to measure the microbial spectrum of antibiotic regimens (spectrum score) and method to identify antibiotic de-escalation events based on application of the score.

DESIGN

Web-based modified Delphi method.

PARTICIPANTS

Physician and pharmacist antimicrobial stewards practicing in the United States recruited through infectious diseases-focused listservs.

METHODS

Three Delphi rounds investigated: organisms and antibiotics to include in the spectrum score, operationalization of rules for the score, and de-escalation measurement. A 4-point ordinal scale was used to score antibiotic susceptibility for organism-antibiotic domain pairs. Antibiotic regimen scores, which represented combined activity of antibiotics in a regimen across all organism domains, were used to compare antibiotic spectrum administered early (day 2) and later (day 4) in therapy. Changes in spectrum score were calculated and compared with Delphi participants' judgments on de-escalation with 20 antibiotic regimen vignettes and with non-Delphi steward judgments on de-escalation of 300 pneumonia regimen vignettes. Method sensitivity and specificity to predict expert de-escalation status were calculated.

RESULTS

Twenty-four participants completed all Delphi rounds. Expert support for concepts utilized in metric development was identified. For vignettes presented in the Delphi, the sign of change in score correctly classified de-escalation in all vignettes except those involving substitution of oral antibiotics. The sensitivity and specificity of the method to identify de-escalation events as judged by non-Delphi stewards were 86.3% and 96.0%, respectively.

CONCLUSIONS

Identification of de-escalation events based on an algorithm that measures microbial spectrum of antibiotic regimens generally agreed with steward judgments of de-escalation status.

Single blind, randomised, comparative study of the Bug Buster kit and over the counter pediculicide treatments against head lice in the United Kingdom

OBJECTIVE

To compare the effectiveness of the Bug Buster kit with a single treatment of over the counter pediculicides for eliminating head lice.

DESIGN

Single blind, multicentre, randomised, comparative clinical study.

SETTING

Four counties in England and one county in Scotland.

PARTICIPANTS

133 young people aged 2-15 years with head louse infestation: 56 were allocated to the Bug Buster kit and 70 to pediculicide treatment.

INTERVENTIONS

Home use of proprietary pediculicides (organophosphate or pyrethroid) or the Bug Buster kit.

MAIN OUTCOME MEASURE

Presence of head lice 2-4 days after end of treatment: day 5 for the pediculicides and day 15 for the Bug Buster kit.

RESULTS

The cure rate using the Bug Buster kit was significantly greater than that for the pediculicides (57% v 13%; relative risk 4.4, 95% confidence interval 2.3 to 8.5). Number needed to treat for the Bug Buster kit compared with the pediculicides was 2.26.

CONCLUSION

The Bug Buster kit was the most effective over the counter treatment for head louse infestation in the community when compared with pediculicides.

Wavelengths of bioconvection patterns

Bioconvection occurs as the result of the collective behaviour of many micro-organisms swimming in a fluid and is realised as patterns similar to those of thermal convection which occur when a layer of water is heated from below. A methodology is developed to record the bioconvection patterns that are formed by aqueous cultures of the single-celled alga Chlamydomonas nivalis. The analysis that is used to quantify the patterns as a function of cell concentration, suspension depth and time is described and experimental results are presented.

Cerebral palsy in Northern Ireland: 1981--93

This paper describes the method of compilation of the Northern Ireland Cerebral Palsy Register (NICPR) and outlines the epidemiology of cerebral palsy (CP) in Northern Ireland in 1981--93 based on an analysis of 784 cases. Multiple and overlapping sources of notification were used to compile the NICPR. Each case was followed up with a standardised assessment completed at age 5 years and validated by a paediatrician. Over 70% of cases were multiply notified, and paediatricians were the most important source of notification. Cases of CP most likely to be under-ascertained included those very mildly affected, cases who died before the register began (death certificates were searched but found to be unreliable) and cases who moved out of the area before their diagnosis was confirmed. The prevalence of CP for the birth period 1981--93 was 2.24 per 1000 livebirths [95% CI 2.08, 2.40]. There were no statistically significant temporal or geographic variations in the rate of CP. Almost half the cases of CP were of low birthweight (<2500 g), and this proportion increased during 1987--89, but decreased (P < 0.01) more recently (1990--93). The proportion of cases weighing <1000 g trebled from 3% in 1981--83 to 10% in 1990--93 (P < 0.01). The most common CP subtype was bilateral spastic cerebral palsy (55%). Just over a quarter (29%) of cases were unable to walk (with/without aids), and one-fifth (22%) had no useful hand/arm function. Almost half (49%) the cases had at least one other impairment (intellectual, sensory impairment or active seizures) in association with their CP. Prevalence rates and the pattern of disability in populations of people with CP can only be evaluated on the basis of the methods of case definition and ascertainment. We have demonstrated the methods necessary to ensure valid, standard and detailed information on CP for the purposes of surveillance, service planning and research.

The role of management in yield improvement of the wheat crop—a review with special emphasis on Western Australia

Modern bread wheat (Triticum aestivum) has been well adapted for survival and production in water-limited environments since it was first domesticated in the Mediterranean basin at least 8000 years ago. Adaptation to various environments has been assisted through selection and cross-breeding for traits that contribute to high and stable yield since that time. Improvements in crop management aimed at improving yield and grain quality probably developed more slowly but the rate of change has accelerated in recent decades. Many studies have shown that the contribution to increased yield from improved management has been about double that from breeding. Both processes have proceeded in parallel, although possibly at different rates in some periods, and positive interactions between breeding and management have been responsible for greater improvements than by either process alone. In southern Australia, management of the wheat crop has focused on improvement of yield and grain quality over the last century. Adaptation has come to be equated with profitability and, recently, with long-term economic and biological viability of the production system. Early emphases on water conservation through the use of bare fallow, crop nutrition through the use of fertilisers, crop rotation with legumes, and mechanisation, have been replaced by, or supplemented with, extensive use of herbicides for weed management, reduced tillage, earlier sowing, retention of crop residues, and the use of ‘break’ crops, largely for management of root diseases. Yields from rainfed wheat crops in Western Australia have doubled since the late 1980s and water-use efficiency has also doubled. The percentage of the crop in Western Australia that qualifies for premium payments for quality has increased 3–4 fold since 1990. Both these trends have been underpinned by the gradual elimination or management of the factors that have been identified as limiting grain yield, grain quality, or long-term viability of the cropping system.

Wilderness Therapy as a Treatment Modality for At-Risk Youth: A Primer for Mental Health Counselors

Many mental health counselors identify adolescent clients as the most "difficult" clients with which to work because it is a challenge to engage them in the counseling experience (Church, 1994; Hanna et al., 1999; Gil, 1996). At-risk youth tend to be ill equipped to engage in traditional counseling interventions, which require them to be verbal and to disclose thoughts and feelings (Hanna et al., 1999; Davis-Berman & Berman, 1994). Wilderness therapy, a specialized approach within adventure-based counseling (Fletcher & Hinkle, 2002), provides an alternative treatment modality that maximizes the client's tendency to spontaneously self-disclose in environments outside the counseling office (Hanna et al.). This article provides an overview of wilderness therapy as a treatment modality and identifies the associated therapeutic factors in an effort to inform mental health counselors.

Are mosquitoes diverted from repellent-using individuals to non-users? Results of a field study in Bolivia

Outside sub-Saharan Africa, Anopheline mosquito exophagic and/or crepuscular behaviour patterns imply that insecticide-treated nets may provide incomplete protection from malaria-infective mosquito bites. Supplementary repellent treatment has been recommended in such circumstances, especially where vectors are exophilic and so are not susceptible to residual insecticide spraying. As maintaining complete usage of repellents in a community is unrealistic, the potential negative impact on non-users of repellent usage by 'neighbours' in the same community needs to be addressed in the context of health policy promoting equity. This study quantifies diversion of host-seeking mosquitoes, from repellent wearing to unprotected individuals, 1 m apart under field conditions in Bolivia. Each of the six volunteer-pairs sat >20 m apart from other pairs. Volunteers were allocated di-ethyl toluamide (DEET) or mineral oil in ethanol control. Treatments were rotated, so that during the trial, both pair-members wore repellent on 72 occasions; both pair-members wore control on 72 occasions; and on 36 occasions, one pair-member wore repellent and the other control. Unprotected (control) pair-members received 36.4% [95% confidence interval (CI): 8.1-72.0%] more Anopheles darlingi landings (P = 0.0096) and 20.4% (95% CI: 0.6-44.0%) more mosquito landings (P = 0.044), when their 'partner' wore repellent than when their partner also wore control. A second, smaller Latin-square trial using 30% lemongrass (Cymbopogon citratus) repellent, with control, obtained 26.0% (95% CI: 5.2-51.0%) more mosquito landings when controls sat with repellent-wearers rather than other controls (P = 0.0159). With incomplete community repellent usage, non-users could be put at an increased risk of malaria. The results also have implications for repellent-efficacy assay design, as protection will appear magnified when mosquitoes are given a choice between repellent-users and non-users.

Seed banks and seedling occurrence in a high Arctic oasis at Alexandra Fjord, Ellesmere Island, Canada

The sizes and floras of the seed banks and seedling communities are described for a variety of habitats in a high Arctic lowland oasis on Ellesmere Island, located at 79° N latitude. Four disturbed habitats had larger seed banks than did four undisturbed habitats (averaging 3070/m2 vs. 63/m2). The seedling densities measured in the disturbed habitats were also larger (1780/m2 vs. 180/m2). The data indicate that sexual reproduction is important to the herbaceous, short-lived, ruderal species which colonize disturbed sites in the high Arctic. This contrasts with the more conservative strategy of stress-tolerant species that occur in relatively closed and undisturbed habitats, which tend to propagate by vegetative mechanisms.

Fractures and dislocations of the foot and ankle in diabetics associated with Charcot joint changes

This study was undertaken to evaluate the occurrence of Charcot joint changes in diabetic patients after fractures and/or dislocations of the foot and ankle. There were 20 fracture/dislocations of the foot and ankle in 18 patients, with an average follow-up of 27 months (range 14-70 months). There were eight fractures of the midfoot, six fractures of the ankle, four fractures of the hindfoot, and two fractures of the forefoot. Eight fractures were followed by the development of Charcot changes: five in the midfoot and one each in the forefoot, hindfoot, and ankle. Of nine fractures recognized early and initially treated by early immobilization or ORIF, seven healed uneventfully. Two fractures, both open injuries, developed soft tissue infection and osteomyelitis, respectively. Of the 11 fractures in which there was a delay in diagnosis and treatment, eight developed Charcot changes. The early recognition and appropriate treatment of fractures in diabetic patients appears to be important in the prevention of Charcot joint changes.

Immunologic parameters in chronic fatigue syndrome, major depression, and multiple sclerosis

The purpose of this study was to evaluate the immune dysfunction hypothesis of chronic fatigue syndrome (CFS) by comparing immunologic data from patients with CFS with data from patients with other fatiguing illnesses--major depression and multiple sclerosis (MS)--and with data from healthy sedentary controls. The subjects were 65 healthy sedentary controls, 71 CFS patients (41 with no axis-I diagnosis), 23 patients with mild MS, and 21 patients with major depression. Blood was sampled and assayed for the following: (1) immunologic serologic variables--circulating immune complexes (i.e., Raji cell and C1q binding), immunoglobulins A, E, G, and M, and IgG subclasses; (2) cell surface activation markers--the proportion of CD4+ cells expressing CD45RA+ and CD45RO+ and the proportion of CD8+ cells expressing CD38+, CD11b-, HLA-DR+ and CD28+; and (3) natural killer (NK) total cell count as well as the proportion of lymphocytes expressing NK cell surface markers (i.e., CD3-/CD16+ and CD56+. Of the 18 variables studied, differences between CFS patients and controls were found only for IgG1 and IgG3. When CFS patients were stratified by the presence or absence of concurrent axis-I disease, it was the group with axis-I disorder that had the lowest IgG1 values-contrary to expectation. When data from patients with MS and major depression were also evaluated, the subclass deficiency was no longer significant. The one group to show evidence for immune activation (i.e., an elevated proportion of CD4+ cells expressing the CD45RA+ activation marker) was the group with mild MS. These data support neither immune dysfunction nor immune activation in CFS or in major depression, for the variables studied. The reductions in IgG subclasses may be an epiphenomenon of patient or control subject composition. In contrast, MS, even in the mild and early stages, as in the patients studied here, is associated with immune activation.

Reducing heterogeneity in chronic fatigue syndrome: a comparison with depression and multiple sclerosis

Chronic fatigue syndrome (CFS) is a heterogeneous illness characterized by a high prevalence of psychiatric problems. We reasoned that we could reduce heterogeneity by excluding patients with psychiatric problems preceding CFS. We compared the functional status, mood, fatigue level, and psychiatric status of this more homogeneous group of CFS patients with the same parameters in patients with mild multiple sclerosis and in patients with major depression or dysthymia. Patients with CFS and those with multiple sclerosis were similar in terms of level of anger, severity of depression, level of anxiety, and frequency of current psychiatric diagnoses. Patients with CFS resembled depressed patients in having impaired vigor and experiencing substantial fatigue and confusion--problems constituting part of the case definition of CFS. The group with CFS was not psychologically vulnerable before the development of this condition and maintained adequate networks of social support despite disabling illness. Stratification to exclude patients with prior psychiatric disease and those with mild CFS allowed us to define a group of patients with CFS who more resembled patients with mild MS than patients with major depression or dysthymia and thus were more likely to have illness with an infectious or immunologic cause. Use of such a stratification strategy should prove important in testing of the viral/immunologic hypothesis of the etiology of CFS.