HYPOKALEMIA IN THE ELDERLY: IS IT ALWAYS DIURETIC-INDUCED?

SUMMARY Serum potassium was measured within 24 hours in 156 patients (48 male, 108 female) with an average age of 81.9 years admitted to the unit with acute illness. Of the 156 patients, 88 (56.4%) were taking diuretics (none was on ACE inhibitors); 20 patients (12.8%) were also on digoxin therapy. In all, 24 patients (16%) had hypokalaemia and 3 (2%) hyperkalaemia. Hypokalaemia was seen in patients associated with acute illness. There was no significant difference between the diuretic and non-diuretic groups. Monitoring of serum potassium is not routinely indicated to detect hypokalaemia in patients on diuretic therapy except in those with severe hepatic or renal impairment or those on digoxin.     

The types of drugs used by HIV-infected injection drug users in a multistate surveillance project: implications for intervention.

OBJECTIVES. This study sought to describe the drugs used by drug injectors infected with human immunodeficiency virus (HIV) and to determine factors associated with the primary injection drug used. METHODS. A cross-section of persons 18 years of age or older reported with HIV or acquired immunodeficiency syndrome (AIDS) to local health departments in 11 US states and cities was surveyed. RESULTS. Of 4162 persons interviewed, 1147 (28%) reported ever having injected drugs. Of these 1147 injectors, 72% primarily injected a drug other than heroin. However, the types of drugs injected varied notably by place of residence. Heroin was the most commonly injected drug in Detroit (94%) and Connecticut (48%); cocaine was the most common in South Carolina (64%), Atlanta (56%), Delaware (55%), Denver (46%), and Arizona (44%); speedball was most common in Florida (46%); and amphetamines were most common in Washington (56%). Other determinants of the type of drug primarily injected were often similar by region of residence, except for heroin use. Polysubstance abuse was common; 75% injected more than one type of drug, and 85% reported noninjected drug use. CONCLUSIONS. Preventing the further spread of HIV will require more drug abuse treatment programs that go beyond methadone, address polysubstance abuse, and adapt to local correlates of the primary drug used.     

MR susceptometry: an external-phantom method for measuring bulk susceptibility from field-echo phase reconstruction maps

A novel method for estimating the susceptibility of an object by using the magnetic resonance (MR) imaging field distortions in an external-reference water bath next to the object is described. The field measurement was obtained with a phase reconstruction from a gradient-echo acquisition. A field model of an arbitrary object in a static magnetic field was discretely calculated from geometry determined from the magnitude reconstruction. Least-squares estimation yields the susceptibility of the object. Required (and proven) assumptions include validity of superposition, object homogeneity, negligible higher-order field terms, field-model accuracy, geometric-model accuracy, and correlation of gradient-echo phase to field distortion. MR susceptometry estimation of phantoms yielded susceptibility estimates that correlated well with known values (r >.9975). This MR susceptometry method is a first step toward quantitation of iron levels through MR imaging phase information in patients with iron overload.     

Cocaine use among heroin users in Spain: the diffusion of crack and cocaine smoking. Spanish Group for the Study on the Route of Administration of Drugs

STUDY OBJECTIVE: To describe the prevalence and patterns of use of crack and cocaine hydrochloride among heroin users in Spain. To explore if the expansion of heroin smoking is accompanied by a similar phenomenon for cocaine. DESIGN: Cross sectional study in 1995. Face to face interviews using a structured questionnaire. SETTING: Three cities with different prevalences of heroin use by smoking: high (Seville), intermediate (Madrid), and low (Barcelona). PARTICIPANTS: 909 heroin users, 452 in treatment and 457 out of treatment. MAIN RESULTS: Last month prevalence of crack use was 62.3% in Seville, 19.4% in Madrid, and 7.7% in Barcelona. Most users in Madrid (86.5%) and Barcelona (100%) generally prepared their own crack, usually with ammonia as alkali; in Seville most users (69.7%) bought preprocessed crack. The proportion of users who began taking cocaine (crack or cocaine hydrochloride) by smoking has increased progressively since the seventies, rising to 74.1% in Seville, 61.5% in Madrid, and 28% in Barcelona in 1992-1995, with the earliest increase in Seville. The factors associated with crack use were: residence in Seville (odds ratio (OR) = 16.3), cocaine hydrochloride use mainly by smoking (OR = 5.0), by sniffing (OR = 2.7) or by injecting (OR = 2.5), heroin use mainly by smoking (OR = 2.8) and weekly use of cannabis (OR = 1.9). CONCLUSIONS: In Spain smoking cocaine may be progressively diffusing from the south west to the north east, similar to what has happened with smoking heroin, but beginning later in time. The factors associated with smoking cocaine are basically ecological or cultural in nature (characteristics of the available drugs and the main route of heroin administration in each city).

 

     

Interactive image-guided management of colloid cysts of the third ventricle.

OBJECT: Image guidance provides a three-dimensional view of the lesion and allows the surgeon to plan a surgical strategy that takes the relationship of the lesion and the surrounding brain into account. We evaluated the degree of resection and the functional outcome of patients with colloid cysts from the third ventricle submitted to surgical resection using interactive image-guided approach. METHOD: Using image-guided methodology and an endoscopic approach we analyzed the functional outcome of 11 patients with diagnosis of colloid cyst of the third ventricle who were treated at our institution from August 1993 to September 2000. The mean age was 39.5 years and the mean follow-up was 36.5 months. Analyzing the clinical outcome, 54.5% of the patients developed short-term memory disturbance in the first 30 days after surgery. None of these patients persisted with this symptomatology for more than one month. In terms of late post-operative morbidity, 1 patient developed persistent post-operative seizures, which were controlled with anti-seizure medications. Complete resection of the cyst was achieved in all patients. CONCLUSIONS: The low rate of complications and high rate of total resection encourage us to continue using the multimodal technique. Longer follow-up and an increase in the number of patients are needed to assess the efficacy of this methodology.     

Body composition estimates using different measurement techniques in a sample of highland subsistence farmers in Guatemala

This study aims at assessing the accuracy of estimates of body composition provided by bioimpedance (BIA) equations developed for U.S. populations when applied to a sample of Guatemalan farmers. If these equations were shown to have low validity, the second objective was to develop more accurate estimates of fat-free mass (FFM). One hundred males and females 19 to 45 years of age were randomly selected from four rural communities in the Western Highlands of Guatemala. Bioimpedance equations explained 59 and 33% of the variation in FFM, with a RMSE of 2.7 and 2.8 kg in males and females, respectively. Body fat (BF) predictions had a lower R². Using the “all possible regressions” procedure, the best subset for prediction of FFM used anthropometric and BIA variables as predictors. The best model for men and women included only anthropometric variables: 75% of the variance in FFM for men and 70% of the variance in women was explained by this model. The RMSE was 2.1 and 1.9 kg for both groups, respectively. It is concluded that FFM can be estimated from anthropometric dimensions with a high degree of accuracy and use of BIA does not provide more valid estimates.     

High-throughput detection of pathogenic yeasts of the genus trichosporon

The need for a rapid and accurate method for the detection of fungal pathogens has become imperative as the incidence of fungal infections has increased dramatically. Herein, we tested the Luminex 100, a novel flow cytometer, for the detection of the medically important genus Trichosporon. This genus was selected as our proof-of-concept model due to the close phylogenetic relationship between the species. The method, which is based on a nucleotide hybridization assay, consists of a combination of different sets of fluorescent beads covalently bound to species-specific capture probes. Upon hybridization, the beads bearing the target amplicons are classified by their spectral addresses with a 635-nm laser. Quantitation of the hybridized biotinylated amplicon is based on fluorescence detection with a 532-nm laser. We tested in various multiplex formats 48 species-specific and group-specific capture probes designed in the D1/D2 region of ribosomal DNA, internal transcribed spacer regions, and intergenic spacer region. Species-specific biotinylated amplicons were generated with three sets of primers to yield fragments from the three regions. The assay was specific and fast, as it discriminated species differing by 1 nucleotide and required less than 50 min following amplification to process a 96-well plate. The sensitivity of the assay allowed the detection of 10(2) genome molecules in PCRs and 10(7) to 10(8) molecules of biotinylated amplification product. This technology provided a rapid means of detection of Trichosporon species with the flexibility to identify species in a multiplex format by combining different sets of beads.