[Chronic fatigue syndrome: psychiatric perspectives]

Chronic fatigue syndrome (CFS) is a common illness of unknown etiology and pathogenesis characterized by severe disabling fatigue and a variety of musculoskeletal, neurocognitive, mood symptoms and sleep disorders lasting at least six months. A significant proportion of patients fulfilling operative criteria for a diagnosis of CFS will also meet criteria for a psychiatric disorder such as depression, somatization or anxiety disorders. Premorbid lifestyle may play a predisposing, and/or perpetuating role in CFS. Some patients improve with time but most remain functionally impaired for several years. A variety of interventions have been used in the treatment and management of CFS. Interventions which have shown promising results include cognitive behavioural therapy and graded exercise therapy. Antidepressants can be useful particularly in the case of comorbid affective disorders. Development of good therapeutic doctor-patient alliance with empathic care is central to the effective management of CFS. In this article we overview the nature and definition of CFS. The prevalence, the prognosis and the psychopathological issues are presented. The management of this controversial syndrome is discussed.

Factors leading to progression of valvular aortic stenosis

The rate of progression of aortic stenosis (AS) in adults is variable. To determine whether clinical or echocardiographic variables are associated with more rapid hemodynamic progression, we identified 91 AS patients (initial valve area < or = 2.0 cm2) with 2 technically adequate studies separated by > or = 6 months. From the first study, left ventricular dimensions and AS severity were measured by standard Doppler-echocardiographic methods. Each aortic valve was graded for severity of calcification and degree of restricted leaflet motion; the sum of these grades provided a severity index reflecting leaflet pathology. Clinical and electrocardiographic variables were abstracted from medical records. Mean age was 68 years (range 29 to 89) and 61 were women. Initial AS severity ranged from an aortic valve area of 0.6 to 2.0 cm2 (median 1.3 cm2). During a mean follow-up of 1.8 years the aortic valve area decreased 0.04 cm2/year. The patient group with more rapid progression (decrease in aortic valve area > or = 0.1 cm2/year) had a larger proportion of men (p <0.01) and patients with an elevated serum creatinine (p = 0.04), a higher left ventricular mass index (p = 0.01), and a higher severity index (p <0.001). Multivariable regression analysis identified the severity index (direct relation) and the initial aortic valve area (inverse relation) as the only independent variables associated with more rapid progression. In conclusion, the rate of AS progression, although highly variable, is more rapid when leaflet calcification is more marked.

Role of hydrazine in the mechanism of isoniazid hepatotoxicity in rabbits

Isoniazid (INH) continues to be a highly effective drug in the chemoprophylaxis and treatment of tuberculosis; however, its use is associated with hepatotoxicity (predominantly hepatic necrosis) in 1-2% of individuals. The INH metabolites, acetylhydrazine and hydrazine, have each been implicated as the causative hepatotoxin in INH-induced hepatotoxicity. Using a model of INH-induced hepatotoxicity in rabbits, in which INH-induced hepatotoxicity manifests as hepatic necrosis, hepatic steatosis (hepatic fat accumulation) and hypertriglyceridaemia (elevated plasma triglycerides), we compared the severity of these measures of toxicity with plasma levels of INH, acetylhydrazine and hydrazine. Plasma INH and acetylhydrazine were not correlated with markers of INH-induced hepatic necrosis or fatty changes. Plasma hydrazine at 32 h was correlated significantly with plasma argininosuccinic acid lyase (ASAL, a sensitive marker of hepatic necrosis) activity as area under the curve (r2 = 0.54, P < 0.002) and log plasma ASAL activity at 48 h after the first dose of INH (r2 = 0.53, p < 0.005), but not with fatty changes. These results show in this model of INH-induced hepatotoxicity in rabbits that hydrazine, and not INH or acetylhydrazine, is most likely involved in the pathogenic mechanism of hepatic necrosis.

Mass-analyzed ion kinetic energy (MIKE) spectrometry and the direct analysis of coca

The technique of mass-analyzed ion kinetic energy (MIKE) spectrometry is briefly reviewed. The direct analysis, without need of prior extraction or chromatographic purification, of cocaine and cinnamoylcocaine in coca plant tissues has been accomplished with this new technique. Detection limits of below 1 ng, with a quantitative accuracy of +/- 30% at the nanogram level, have been demonstrated.

Rapid determination of light halogenated hydrocarbons in urine

We describe a rapid method for determining light halogenated hydrocarbons (LHH) in urine by electron capture gas-liquid chromatography. The hydrocarbons are extracted from urine into pentane. A 2-microliter injection of the pentane extract provides a detection limit of less than 1 microgram/liter.

Rapid determination of light halogenated hydrocarbons in urine

We describe a rapid method for determining light halogenated hydrocarbons (LHH) in urine by electron capture gas-liquid chromatography. The hydrocarbons are extracted from urine into pentane. A 2-microliter injection of the pentane extract provides a detection limit of less than 1 microgram/liter.