Expression of mRNAs encoding uncoupling proteins in human skeletal muscle: effects of obesity and diabetes

To explore the potential role of the uncoupling protein (UCP) family in human obesity and diabetes, we have used the reverse transcription-polymerase chain reaction to quantify UCP mRNA expression in human skeletal muscle. Levels of mRNA for UCP2, and for both short (UCP3S) and long (UCP3L) forms of UCP3, were highly correlated in individuals, indicating that gene transcription of these UCPs may be coordinately regulated by common mechanisms. In normal glucose-tolerant individuals, muscle UCP2 mRNA levels were positively correlated with percentage of body fat and with BMI (r = 0.6 and P < 0.05 for both). UCP3S mRNA levels were also positively correlated with percentage of body fat (r = 0.52, P < 0.05), and UCP3L mRNA tended to increase as a function of obesity (0.05 < P < 0.1). UCP mRNA levels, however, were not correlated with resting metabolic rate. UCP3S and UCP3L mRNA levels (P < 0.05) and the UCP2 mRNA level (P = 0.09) were increased by 1.8- to 2.7-fold in type 2 diabetes, an effect that could not be explained by obesity. No significant difference was found for UCP2, UCP3S, or UCP3L mRNA levels between insulin-sensitive and insulin-resistant nondiabetic subgroups. We conclude that 1) skeletal muscle mRNA levels encoding UCP2 and UCP3 are correlated among individuals and may be coordinately regulated; 2) UCP3 expression is not regulated by differential effects on UCP3L and UCP3S forms of the mRNA; and 3) UCP mRNA expression tends to increase in muscle as a function of obesity but not of resting metabolic rate or insulin resistance, and is increased in patients with type 2 diabetes.

Diabetes research in South Carolina: past, present, and future

Medical investigators in South Carolina have been on the "cutting edge" of diabetes research for a number of decades. Despite this fact, our state ranks second in the nation in diabetes prevalence, and diabetes complications are more severe here than anywhere else. It is from the efforts of these investigators that our hope for a brighter future comes. Through a concerted effort toward prevention, improvements in care, and investigation of the pathophysiology of diabetes and its complications, researchers may reduce the substantial burden of diabetes in our state and throughout the world.

Capacitative Ca2+ entry and the regulation of smooth muscle tone

In many non-excitable cells, activation of phospholipase C-linked receptors results in a biphasic increase in the cytosolic Ca2+ concentration; an initial transient increase, owing to the release of Ca2+ from the endoplasmic/sarcoplasmic reticulum (ER/SR), is followed by a much smaller but sustained elevation, which often involves capacitative Ca2+ entry, where depletion of Ca2+ within the ER signals the opening of store-operated Ca2+ channels in the plasma membrane. However, in excitable cells such as smooth muscle, the role of capacitative Ca2+ entry is less clear and the main Ca2+ entry mechanisms responsible for sustained cellular activation have been considered to be either voltage-operated or receptor-operated Ca2+ channels. Although store-regulated Ca2+ entry was known to occur following agonist activation of smooth muscle, it was believed to be important only for the re-filling of the depleted SR and not as a source of activator Ca2+ for the contractile mechanisms. Here, Alan Gibson, Ian McFadzean, Pat Wallace and Christopher Wayman review recent evidence that capacitative Ca2+ entry might indeed be important for the regulation of smooth muscle tone, and that it might provide an important for pharmacological intervention.

Evidence for defects in the trafficking and translocation of GLUT4 glucose transporters in skeletal muscle as a cause of human insulin resistance

Insulin resistance is instrumental in the pathogenesis of type 2 diabetes mellitus and the Insulin Resistance Syndrome. While insulin resistance involves decreased glucose transport activity in skeletal muscle, its molecular basis is unknown. Since muscle GLUT4 glucose transporter levels are normal in type 2 diabetes, we have tested the hypothesis that insulin resistance is due to impaired translocation of intracellular GLUT4 to sarcolemma. Both insulin-sensitive and insulin-resistant nondiabetic subgroups were studied, in addition to type 2 diabetic patients. Biopsies were obtained from basal and insulin-stimulated muscle, and membranes were subfractionated on discontinuous sucrose density gradients to equilibrium or under nonequilibrium conditions after a shortened centrifugation time. In equilibrium fractions from basal muscle, GLUT4 was decreased by 25-29% in both 25 and 28% sucrose density fractions and increased twofold in both the 32% sucrose fraction and bottom pellet in diabetics compared with insulin-sensitive controls, without any differences in membrane markers (phospholemman, phosphalamban, dihydropyridine-binding complex alpha-1 subunit). Thus, insulin resistance was associated with redistribution of GLUT4 to denser membrane vesicles. No effects of insulin stimulation on GLUT4 localization were observed. In non-equilibrium fractions, insulin led to small GLUT4 decrements in the 25 and 28% sucrose fractions and increased GLUT4 in the 32% sucrose fraction by 2.8-fold over basal in insulin-sensitive but only by 1.5-fold in both insulin-resistant and diabetic subgroups. The GLUT4 increments in the 32% sucrose fraction were correlated with maximal in vivo glucose disposal rates (r = +0.51, P = 0.026), and, therefore, represented GLUT4 recruitment to sarcolemma or a quantitative marker for this process. Similar to GLUT4, the insulin-regulated aminopeptidase (vp165) was redistributed to a dense membrane compartment and did not translocate in response to insulin in insulin-resistant subgroups. In conclusion, insulin alters the subcellular localization of GLUT4 vesicles in human muscle, and this effect is impaired equally in insulin-resistant subjects with and without diabetes. This translocation defect is associated with abnormal accumulation of GLUT4 in a dense membrane compartment demonstrable in basal muscle. We have previously observed a similar pattern of defects causing insulin resistance in human adipocytes. Based on these data, we propose that human insulin resistance involves a defect in GLUT4 traffic and targeting leading to accumulation in a dense membrane compartment from which insulin is unable to recruit GLUT4 to the cell surface.

Self-reported allergy-related symptoms and psychological morbidity in primary care

OBJECTIVE

To examine the relationship between allergy-related symptoms, food intolerance and psychological distress in primary care.

METHODS

Two thousand three hundred and thirty two adults in five General Practices in the South of England completed questionnaires regarding allergy-related symptoms and psychological symptoms, but no association was demonstrated between a history of diagnosed or treated asthma, eczema or hay fever and psychological morbidity. Cases of food intolerance had lower levels of psychological distress than expected compared to hospital samples. Current, but not past wheezing and eczema, was associated with an excess of life stresses in the previous six months.

CONCLUSIONS

The association between psychological distress and the label of food allergy/intolerance found in specialist care does not extend to primary care.

The chicken CP49 gene contains an extra exon compared to the human CP49 gene which identifies an important step in the evolution of the eye lens intermediate filament proteins

The gene structure for chicken CP49 gene is presented. It differs from the human CP49 gene with the presence of an extra exon in helix IB and the apparent loss of an intron, intron H. The CP49 gene localises to chromosome 2 in the chicken genome where it is flanked by homologues that map to human chromosome 10p13 (VIM) 6p24-p23 (BMP6). Two transcripts, CP49 and CP49ins, are produced from the single chicken CP49 gene. The difference is a 49-amino-acid insertion in helix IB of CP49 that is encoded by a novel exon found in the chicken CP49 gene. An extended helix IB is believed to be a characteristic of the ancestral intermediate filament protein as it is found in many invertebrate intermediate filament proteins but has been lost from all vertebrate intermediate filament proteins except the nuclear lamins. Although the intron position and length of the helix IB insert sequences in CP49ins differ to those found both in the invertebrate intermediate filament proteins and the vertebrate lamins, the CP49 gene is the first vertebrate cytoplasmic intermediate filament protein to be described with an extended helix IB. The chicken CP49 gene is also the first where differential splicing can remove such a feature. Human and bovine CP49 appear to have lost the helix IB insert sequences, and so the avian CP49 gene provides an interesting evolutionary link between the eye lens proteins and the ancestral intermediate filament protein.

The future role of telemedicine at the interface between primary and secondary care

Telemedicine has been in existence for 25 years. Owing to the primitive state of technological development and poor telecommunications, early projects could not be sustained. Recent improvements in technology and communications, together with a convergence of political and economic trends, has led to a massive surge in development. In the UK one promising application is to link GPs with hospital specialists. This offers the potential for improved quality of communication, more effective use of expensive resources, and more convenient delivery of medical services to the patient.

The prevalence and morbidity of chronic fatigue and chronic fatigue syndrome: a prospective primary care study

OBJECTIVES

This study examined the prevalence and public health impact of chronic fatigue and chronic fatigue syndrome in primary care patients in England.

METHODS

There were 2376 subjects, aged 18 through 45 years. Of 214 subjects who fulfilled criteria for chronic fatigue, 185 (86%) were interviewed in the case-control study. Measures included chronic fatigue, psychological morbidity, depression, anxiety, somatic symptoms, symptoms of chronic fatigue syndrome, functional impairment, and psychiatric disorder.

RESULTS

The point prevalence of chronic fatigue was 11.3%, falling to 4.1% if comorbid psychological disorders were excluded. The point prevalence of chronic fatigue syndrome was 2.6%, falling to 0.5% if comorbid psychological disorders were excluded. Rates did not vary by social class. After adjustment for psychological disorder, being female was modestly associated with chronic fatigue. Functional impairment was profound and was associated with psychological disorder.

CONCLUSIONS

Both chronic fatigue and chronic fatigue syndrome are common in primary care patients and represent a considerable public health burden. Selection bias may account for previous suggestions of a link with higher socioeconomic status.

The metabolic significance of leptin in humans: gender-based differences in relationship to adiposity, insulin sensitivity, and energy expenditure

Leptin is an adipocyte-derived hormone that interacts with a putative receptor(s) in the hypothalamus to regulate body weight. The relationship of leptin to metabolic abnormalities associated with obesity together with hormonal and substrate regulation of leptin have not been extensively studied. Therefore, 116 subjects (62 men and 54 women) with a wide range of body weight [body mass index (BMI), 17-54 kg/m2] were characterized on a metabolic ward with regard to body composition, glucose intolerance, insulin sensitivity, energy expenditure, substrate utilization, and blood pressure. Eighty-five of the subjects had normal glucose tolerance (50 men and 35 women), and 31 had noninsulin-dependent diabetes mellitus (12 men and 19 women). In both men and women, fasting leptin levels were highly correlated with BMI (r = 0.87 and r = 0.88, respectively) and percent body fat (r = 0.82 and r = 0.88, respectively; all P < 0.0001). However, men exhibited lower leptin levels at any given measure of obesity. Compared with those in men, leptin levels rose 3.4-fold more rapidly as a function of BMI in women [leptin = 1.815 (BMI)-31.103 in women; leptin = 0.534 (BMI)-8.437 in men] and 3.2 times more rapidly as a function of body fat [leptin = 1.293 (% body fat)-24.817 in women; leptin = 0.402 (% body fat)-3.087 in men]. Hyperleptinemia was associated with insulin resistance (r = -0.57; P < 0.0001) and high waist to hip ratio (r = 0.75; P < 0.0001) only in men. On the other hand, during the hyperinsulinemic euglycemic clamp studies, hyperinsulinemia acutely increased leptin concentrations (20%) only in women. There was no correlation noted between fasting leptin levels and either resting energy expenditure or insulin-induced thermogenesis in men or women (P = NS). In stepwise and multiple regression models with leptin as the dependent variable, noninsulin-dependent diabetes mellitus did not enter the equations at a statistically significant level. The data indicate that there are important gender-based differences in the regulation and action of leptin in humans. Serum leptin levels increase with progressive obesity in both men and women. However, for any given measure of obesity, leptin levels are higher in women than in men, consistent with a state of relative leptin resistance. These findings have important implications regarding differences in body composition in men and women. The observation that serum leptin is not related to energy expenditure rates suggests that leptin regulates body fat predominantly by altering eating behavior rather than calorigenesis.

Acute human trial of the floating mass transducer

Five patients underwent acute implantation of the Floating Mass Transducer (FMT) to evaluate the ability of the FMT to produce measurable auditory thresholds when temporarily placed in the middle ears of patients undergoing routine stapedotomy procedures. The FMT was placed on the long process of the incus in an inferior position, as is planned for clinical application, and in two additional positions. The ability of the FMT to produce measurable auditory thresholds was demonstrated in all patients. Results were affected by the lack of a healing period, the presence of a fixed stapes and an open middle ear space, and patient sedation.

Muscle Rad expression and human metabolism: potential role of the novel Ras-related GTPase in energy expenditure and body composition

Ras associated with diabetes (Rad), a new ras-related GTPase, was recently identified by subtractive cloning as an mRNA in skeletal muscle that is overexpressed in NIDDM. To better understand its metabolic significance, we measured skeletal muscle Rad expression in well-characterized insulin sensitive (IS) and insulin resistant (IR) subjects with normal glucose tolerance and in untreated NIDDM patients. We found no differences in expression of Rad mRNA levels among IS, IR, and NIDDM groups using a ribonuclease protection assay (0.22 +/- 0.06, 0.13 +/- 0.01, and 0.16 +/- 0.02 relative units, respectively; NS) and no differences in Rad protein expression using a specific anti-peptide Rad antibody (1.05 +/- 0.18, 1.14 +/- 0.08, and 1.08 +/- 0.21 units/mg protein, respectively; NS). However, Rad protein levels were positively correlated with BMI (r = 0.43, P = 0.03) and percentage body fat (r = 0.55, P < 0.005), two independent measures of obesity, and negatively correlated with resting metabolic rate (r = 0.49, P = 0.01). In multiple regression analyses, percentage body fat and resting metabolic rate independently accounted for 30 and 10% of individual variability in muscle Rad protein expression. In conclusion, Rad expression in skeletal muscle is not altered as a function of insulin resistance or NIDDM in humans. However, these data, for the first time, implicate a role for Rad in regulating body composition and energy expenditure and provide a framework for studies designed to elucidate Rad's cellular functions.

Is there a role for telemedicine in an urban environment?

Semi-structured interviews were carried out to determine the expectations of potential participants in a feasibility study of teleconsulting. General practitioners produced high positive scores in all areas. Hospital consultants produced high scores but were more critical of technical performance and administrative arrangements. Patient satisfaction with teleconsulting was generally good. The results suggested that teleconsulting was both feasible and acceptable to the users.

Can telemedicine be used to improve communication between primary and secondary care?

OBJECTIVE

To test feasibility and acceptability of teleconferencing routine outpatient consultations.

DESIGN

Exploratory trial of teleconferenced outpatient referrals of general practitioners.

SETTING

An inner city teaching hospital and surrounding general practices.

SUBJECTS

Six general practices linked to hospital outpatient clinics.

MAIN OUTCOME MEASURES

Levels of participants' satisfaction measured with self administered questionnaires.

RESULTS

54 teleconsultations were performed in 10 different specialties. Few serious technical problems were encountered, and high levels of satisfaction with the consultations were reported by patients, hospital specialists, and general practitioners.

CONCLUSIONS

Teleconferenced consultations for routine outpatient referrals with joint participation of general practitioner were feasible. These may have an important potential benefit for improving communication between primary and secondary care.

Clinical breast evaluation skills of house officers and students

Current health care reform is placing primary care physicians in an increasingly significant role as the front-line providers of women's health care. It is critical that primary care physicians as well as surgeons develop the knowledge base, physical examination skills, and interpersonal skills necessary to care for patients with breast cancer. This study uses a standardized patient breast case in an Objective Structured Clinical Examination (OSCE) format to objectively assess clinical breast evaluation skill performance by house officers and medical students. Performance of USC medical students, exposed to a uniform clinical breast evaluation curriculum, were compared with MSIVs from four other medical schools, and postgraduate year I and II categorical surgical residents. USC medical students were found to maintain performance between an initial surgical OSCE breast station and a delayed clinical practice exam (CPX) reexam as MSIVs (breast exam, P = 0.21; patient-physician interaction, P = 0.67). USC MSIVs had statistically significantly higher performance on the CPX breast station when compared with other MSIVs (T = 11.701, two-tailed test, P = 0.0001). House officers demonstrated significantly poorer skills than medical students (P = 0.03). An incoming housestaff group showed improvement with clinical breast evaluation checklists and orientation as part of their intern orientation program and ongoing curriculum.

Reflectometric frequency-modulation continuous-wave distributed fiber-optic stress sensor with forward coupled beams

A distributed optical-fiber stress sensor whose principle of operation is based on the frequency-modulation continuous-wave technique is reported. The sensor consists of a length of birefringent fiber with a mirror attached to one end, a diode laser, and a p-i-n photodiode detector. The intensity and the location of an applied stress are determined simultaneously by detecting the amplitude and the frequency of the beat signal, which is produced by two forward-coupled mode beams. The system was found to have a reasonable spatial resolution of 0.85 m (rms error) in a sensing range of 100 m. The advantages and limitations of the sensor are also discussed.

Inhibition of nitric oxide synthase by isothioureas: cardiovascular and antinociceptive effects

A range of substituted isothiourea compounds including S-isopropylisothiourea (IPTU), S-methylisothiourea (SMT), S-ethylisothiourea (ETU), N-pentylisothiourea (PTU), S-(2 aminoethyl)isothiourea (AETU), and S-acetamidoisothiourea (AATU) inhibit mouse spinal cord/cerebellar neuronal nitric oxide synthase (nNOS) and bovine aortic endothelial cell eNOS in vitro. IP administration of isothioureas increased mean arterial blood pressure of the urethane-anaesthetised mouse (rank order of effect: IPTU > ETU > SMT > AETU). PTU and AATU were without vasopressor activity. IPTU (50 mg/kg, IP) inhibited late phase formalin-induced hindpaw licking behaviour in the mouse while SMT (50 mg/kg, IP) was without effect. Neither compound influenced the formalin-induced increase in hindpaw weight reflecting a lack of significant peripheral antioedema effect in this model. IPTU (50 mg/kg, IP) but not SMT (50 mg/kg, IP) inhibited mouse spinal cord and cerebellar NOS activity measured ex vivo in animals killed 45 min after injection. The present study confirms the potent NOS inhibitory effect of selected substituted isothioureas in vitro. Little or no isoform selectivity (i.e., nNOS vs. eNOS) was apparent. The potent vasopressor effect of isothioureas indicates that these compounds may be of limited use as tools to study the role of nitric oxide in pain perception.

Health advice for Asian women with diabetes

The prevalence of non-insulin dependent diabetes mellitus is high in the South Asian population living in the UK. Innovative approaches are required to meet the special needs of this client group. This project aims to provide education, support, exercise classes and advice to Asian women with diabetes.

Inhibition of nitric oxide synthase by 1-(2-trifluoromethylphenyl) imidazole (TRIM) in vitro: antinociceptive and cardiovascular effects

1. The ability of a range of substituted imidazole compounds to inhibit mouse cerebellar neuronal nitric oxide synthase (nNOS), bovine aortic endothelial NOS (eNOS) and inducible NOS (iNOS) from lungs of endotoxin-pretreated rats was investigated. In each case the substrate (L-arginine) concentration employed was 120 nM. 2. 1-(2-Trifluoromethylphenyl) imidazole (TRIM) was a relatively potent inhibitor of nNOS and iNOS (IC50S of 28.2 microM and 27.0 microM respectively) but was a relatively weak inhibitor of eNOS (IC50, 1057.5 microM). The parent compound, imidazole, was a weak inhibitor of all three NOS isoforms (IC50S: nNOS, 290.6 microM; eNOS, 101.3 microM; iNOS, 616.0 microM). Substitution of imidazole with a phenyl group to yield I-phenylimidazole (PI) resulted in an isoform non-selective increase in inhibitory potency (IC50S: nNOS, 72.1 microM; eNOS, 86.9 microM; iNOS, 53.9 microM). Further substitution of the attached phenyl group resulted in an increase in nNOS and a decrease in eNOS inhibitory potency as in TRIM, 1-chlorophenylimidazole (CPI; IC50S: nNOS, 43.4 microM; eNOS, 392.3 microM; iNOS, 786.5 microM) and 1-(2,3,5,6-tetrafluorophenyl) imidazole (TETRA-FPI; IC50S; nNOS, 56.3 microM; eNOS, 559.6 microM; iNOS, 202.4 microM). 3. The ability of TRIM to inhibit mouse cerebellar nNOS activity in vitro was influenced by the concentration of L-arginine (0.12-10.0 microM) in the incubation medium. When mouse cerebellar nNOS was used as enzyme source a double reciprocal (Lineweaver-Burk) plot in the presence/absence of TRIM (50 microM) revealed a competitive inhibitory profile. The K(m) for L-arginine and the Ki for TRIM calculated from these data were 2.4 microM and 21.7 microM, respectively. The ability of TRIM to inhibit mouse cerebellar nNOS activity in vitro was unaffected by varying the time of exposure of the enzyme to TRIM from 0-60 min at 0 degree C. 4. TRIM exhibits potent antinociceptive activity in the mouse as evidenced by inhibition of acetic acid induced abdominal constrictions. The ED50 for TRIM following i.p. administration was 20 mg kg-1 (94.5 mumol kg-1). The antinociceptive effect of TRIM was reversed by pretreatment of animals with L-arginine (50 mg kg-1, i.p.) and was not accompanied by sedation, motor ataxia or behavioural changes (rearing, crossing, circling, dipping) as assessed by use of a box maze procedure. 5. L-NG nitro arginine methyl ester (L-NAME, 20 mg kg-1, i.v.) but not TRIM (0.5-20 mg kg-1, i.v.) increased mean arterial blood pressure (MAP) in the urethane-anaesthetized rat. 6. L-NAME (100 microM) potentiated the contractile response of the rabbit isolated aorta to phenylephrine (ED50; 0.084 +/- 0.01 microM in the presence and 0.25 +/- 0.05 microM in the absence of L-NAME; maximum response, 7.7 +/- 0.4 g in the presence and 5.6 +/- 0.5 g in the absence of L-NAME, n = 6, (P < 0.05) whilst TRIM (1-100 microM) was without effect. L-NAME (100 microM) but not TRIM (1-100 microM) also reduced carbachol-induced relaxation of the phenylephrine-precontracted rabbit aorta preparation. 7. L-NAME (50 microM) potentiated the vasoconstrictor effect of bolus-injected noradrenaline (10-1000 nmol) and reduced the vasodilator effect of carbachol (10 microM) added to the Krebs reservoir in the rat perfused mesentery preparation. L-NAME (50 microM) also reduced nitric oxide (NO) release (measured by chemiluminescence of nitrite in the Krebs perfusate) in response to noradrenaline (100 nmol; 53.8 +/- 4.0 pmol ml-1 in the presence and 84.8 +/- 8.0 pmol ml-1 in the absence of L-NAME, n = 15, P < 0.05) and carbachol (10 microM; 63.9 +/- 5.0 pmol ml-1 in the presence and 154.0 +/- 9.0 pmol ml-1 in the absence of L-NAME, n = 15, P < 0.05). TRIM (50 microM) did not affect either the vasoconstrictor response to noradrenaline or the vasodilator response to carbachol or the accompanying release of NO from the perfused rat mesentery.

Aboriginal health in the peel region of Western Australia

OBJECTIVE

A cross sectional survey of the Aboriginal people living in Mandurah, Pinjarra and Waroona (South West district of Western Australia) was undertaken to determine their health status and health service utilisation patterns.

METHOD

The project was funded by the General Practice Research Program and conducted by the Forrest House Medical Group. The data were collected by an Aboriginal research assistant with tertiary training in public health. Demographic and health characteristics, prevalence of common acute and chronic conditions, rates of pregnancy, use of antenatal and women's health screening services, use of legal and illegal drugs, and satisfaction with local health services were estimated.

RESULTS

A total of 57 families were interviewed, they comprised 271 adults and children. Acute and chronic health problems were common, the rate of pregnancy was high for young women, and the immunisation status was poor among children. Respondents were more likely to express satisfaction with the Aboriginal health worker and local doctor services than with the local hospital service. The local doctor's surgery was the most often used service.

CONCLUSION

The survey included 70% of the Peel region's Aboriginal families and is one of the few comprehensive descriptions of the health status of an urban Aboriginal group. Thus it should provide an excellent basis for the re-orientation of health services and the development of environmental and educational interventions to improve the health status of the Aboriginal people living in the Peel region. An advisory committee has been formed to take action from the findings.

Psychological symptoms, somatic symptoms, and psychiatric disorder in chronic fatigue and chronic fatigue syndrome: a prospective study in the primary care setting

OBJECTIVE

This study assessed relationships among psychological symptoms, past and current psychiatric disorder, functional impairment, somatic symptoms, chronic fatigue, and chronic fatigue syndrome.

METHOD

A prospective cohort study was followed by a nested case-control study. The subjects, aged 18-45 years, had been in primary care for either clinical viral infections or a range of other problems. Questionnaire measures of fatigue and psychological symptoms were completed by 1,985 subjects 6 months later; 214 subjects with chronic fatigue were then compared with 214 matched subjects without fatigue. Assessments were made with questionnaires, interviews, and medical records of fatigue, somatic symptoms, psychiatric disorder, and functional impairment.

RESULTS

Subjects with chronic fatigue were at greater risk than those without chronic fatigue for current psychiatric disorder assessed by standardized interview (60% versus 19%) or by questionnaire (71% versus 31%). Chronic fatigue subjects were more likely to have received psychotropic medication or experienced psychiatric disorder in the past. There was a trend for previous psychiatric disorder to be associated with comorbid rather than noncomorbid chronic fatigue. Most subjects with chronic fatigue syndrome also had current psychiatric disorder when assessed by interview (75%) or questionnaire (78%). Both the prevalence and incidence of chronic fatigue syndrome were associated with measures of previous psychiatric disorder. The number of symptoms suggested as characteristics of chronic fatigue syndrome was closely related to the total number of somatic symptoms and to measures of psychiatric disorder. Only postexertion malaise, muscle weakness, and myalgia were significantly more likely to be observed in chronic fatigue syndrome than in chronic fatigue.

CONCLUSIONS

Most subjects with chronic fatigue or chronic fatigue syndrome in primary care also meet criteria for a current psychiatric disorder. Both chronic fatigue and chronic fatigue syndrome are associated with previous psychiatric disorder, partly explained by high rates of current psychiatric disorder. The symptoms thought to represent a specific process in chronic fatigue syndrome may be related to the joint experience of somatic and psychological distress.