Basic statistics of PM2.5 and PM10 in the atmosphere of Mexico City

The high levels of fine particulate matter in Mexico City are of concern since they may induce severe public health effects as well as the attenuation of visible light. Sequential filter samplers were used at six different sites from 23 February to 22 March 1997. The sampling campaign was carried out as part of the project 'Investigación sobre Materia Particulada y Deterioro Atmosferico-Aerosol and Visibility Evaluation Research'. This research was a cooperative project sponsored by PEMEX and by the US Department of Energy. Sampling sites represent the different land uses along the city, the northwest station, Tlalnepantla, is located in a mixed medium income residential and industrial area. The northeast station, Xalostoc, is located in a highly industrialized area, Netzahualcoyotl is located in a mixed land use area, mainly commercial and residential. Station La Merced is located in the commercial and administrative district downtown. The southwest station is located in the Pedregal de San Angel, in a high-income neighborhood, and the southeast station located in Cerro de la Estrella is a mixed medium income residential and commercial area. Samples were collected four times a day in Cerro de la Estrella (CES), La Merced (MER) and Xalostoc (XAL) with sampling periods of 6 h. In Pedregal (PED), Tlalnepantla (TLA) and Netzahualcoyot1 (NEZ) sampling periods were every 24 h. In this paper the basic statistics of PM2.5 and PM10 mass concentrations are presented. The average results showed that 49, 61, 46, 57, 51 and 44% of the PM10 consisted of PM2.5 for CES, MER, XAL, PED, TLA and NEZ, respectively. The 24-h average highest concentrations of PM25 and PM10 were registered at NEZ (184 and 267 microg/m3) and the lowest at PED (22 and 39 microg/m3). The highest PM10 correlations were between XAL-CES (0.79), PED-TLA (0.80). In contrast, the highest PM2.5 correlations were between CES-PED (0.74), MER-CES (0.73) and TLA-PED (0.72), showing a lower correlation than the PM10 one. The results of the PM10 from 12.00 to 18.00 h at CES and MER presented the highest variability and also the highest median concentrations, meanwhile XAL showed them from 06.00 to 12.00 h. The highest variability and median concentrations of PM2.5 were from 06.00 to 12.00 h for the three stations.

Personal exposure to benzene, toluene and xylene in different microenvironments at the Mexico City metropolitan zone

The Mexico City Metropolitan Zone (ZMCM) population's exposure to benzene, toluene and xylene was measured at different microenvironments to establish basic indicators of the presence and effects of these characteristic volatile organic compounds (VOC). In particular, VOC personal exposures were measured in different microenvironments during a 5-day working week, with 12-h daily periods. We have found a good agreement of our results with the registered VOC levels of the Metropolitan Automated Monitor System (RAMA) for the corresponding period. From our results, we expect to generate useful information to evaluate the health effects of these VOCs on exposed people.

Experimental measurement of the statistics of the scattered intensity from particles on surfaces

We analyze the statistics of the co-polarized and cross-polarized scattered intensity from a flat substrate contaminated with spherical particles including multiple scattering between them. Both Gaussian and non-Gaussian regimes are considered. In particular, we focus on both the cross-polarized component and the probability of detecting zeros in the cross-polarized intensity, P(Icross=0). As it is shown, the latter gives information about particle interaction and can be measured with higher accuracy than other statistical parameters. A theoretical model for P(Icross=0) is presented for spherical Rayleigh scatterers. An scattering experiment was carried out to verify this model.

Quantitative determination of the loop diuretic bumetanide in urine and pharmaceuticals by high-performance liquid chromatography with amperometric detection

A high-performance liquid chromatographic method with amperometric detection has been developed for the determination of the diuretic bumetanide using a microBondapak C18 column. The mobile phase consists of a 50:50 acetonitrile-water mixture containing 5mM KH2PO4-K2HPO4 (pH 4.0). The compound is monitored at +1350 mV with an amperometric detector equipped with a glassy carbon working electrode. A liquid-liquid or solid-liquid extraction is done prior to chromatographic analysis in order to avoid the interferences found in the urine matrix. The percentages of recovery obtained are 71%+/-1% for liquid-liquid extraction and 84.2%+/-0.7% for solid-liquid extraction. The method developed has a linear concentration range from 50 to 499 ng/mL with a reproducibility in terms of relative standard deviation of 1.73% and 3.85% for a concentration level of 70 ng/mL and 237 ng/mL, respectively, and a detection limit of 0.25 ng/mL (3:1 signal-to-noise ratio). The method is applied to the determination of bumetanide in pharmaceutical formulations and urine obtained from hypertensive patients and healthy volunteers after the ingestion of a therapeutic dose of Fordiuran (1 mg bumetanide).

Validity of the Agency for Healthcare Research and Quality clinical practice guidelines: how quickly do guidelines become outdated?

CONTEXT

Practice guidelines need to be up-to-date to be useful to clinicians. No published methods are available for assessing whether existing practice guidelines are still valid, nor does any empirical information exist regarding how often such assessments need to be made.

OBJECTIVES

To assess the current validity of 17 clinical practice guidelines published by the US Agency for Healthcare Research and Quality (AHRQ) that are still in circulation, and to use this information to estimate how quickly guidelines become obsolete.

DESIGN, SETTING, AND PARTICIPANTS

We developed criteria for defining when a guideline needs updating, mailed surveys to members of the original AHRQ guideline panels (n = 170; response rate, 71%), and searched the literature for evidence through March 2000 (n = 6994 titles yielding 173 articles plus 159 new guidelines on the same topics).

MAIN OUTCOME MEASURES

Identification of new evidence calling for a major, minor, or no update of the 17 guidelines; survival analysis of the rate at which guidelines became outdated.

RESULTS

For 7 guidelines, new evidence and expert judgment indicated that a major update is required; 6 were found to be in need of a minor update; 3 were judged as still valid; and for 1 guideline, we could reach no conclusion. Survival analysis indicated that about half the guidelines were outdated in 5.8 years (95% confidence interval [CI], 5.0-6.6 years). The point at which no more than 90% of the guidelines were still valid was 3.6 years (95% CI, 2.6-4.6 years).

CONCLUSIONS

More than three quarters of the AHRQ guidelines need updating. As a general rule, guidelines should be reassessed for validity every 3 years.

Value of limited necropsy in HIV-positive patients

We performed limited autopsy with histological examination of tissue cores obtained percutaneously using the Tru-Cut needle and the Jamshidi trocar in 150 adult HIV-positive patients. Data were compared retrospectively with the antemortem clinical diagnosis. Eighty-one percent of the patients were male, and 78% were intravenous drug users. Specimens were obtained from the brain, liver, lung, bone marrow, and kidney of most patients. The main findings included liver cirrhosis in 22 cases (associated with HCV infection in 81%), Pneumocystis carinii pneumonia in 21, Cytomegalovirus (CMV) infection in 19, Mycobacterium avium-intracellulaire (MAI) infection in 17, bacterial pneumonia in 14, tuberculosis in 12, and lymphoma in 13 cases. Forty-six (30.6%) patients had at least one clinical diagnosis that was confirmed by autopsy, i.e., there was 40.6% agreement between pre- and postmortem findings. Forty-six (30.6%) patients had at least one clinical diagnosis that was not confirmed at autopsy, whereas 41 (27.3%) had at least one AIDS-related or unrelated disease that was not suspected clinically. The results obtained by limited autopsy are principally comparable to those achieved by full necropsy, with the advantages of decreasing the contagious risk, saving cost and time, including a rapid final diagnosis, and easily obtaining the consent for postmortem examination so that necropsy studies may be performed on a larger number of patients, thus contributing to a better understanding of the spectrum of HIV infection in our environment.

[Antiganglioside antibodies: when, which and for what]

BACKGROUND

We report our experience in the study of antiganglioside antibodies and define their clinical value establishing associations between clinical syndromes and immunological findings.

METHODS

We analysed 275 sera: Guillain-Barré syndrome (GBS) (78), Miller-Fisher syndrome (MFS) (37), chronic inflammatory demyelinating polyneuroapthy (CIDP) (17), multifocal motor neuropathy (NMM) (42), chronic axonal mixed polyneuropathy (PNP) (54), amyotrophic lateral sclerosis (ALS) (28) and lower motor neuron disease (LMND) (17). We have studied the presence of IgG and IgM antibodies to 9 gangliosides using ELISA and TLC.

RESULTS

We have detected anti-GQ1b antibodies in 36/37 (97,3%) of patients with MFS, being undetectable after 4 weeks in 83%. A 34 % (26/78) of patients with GBS were positive for several antiganglioside specificities being GalGalNAc the most frequent (54%). Two out of three sera positive for GD1a corresponded to axonal Guillain-Barré. IgM class anti-GM1 antibodies were positive in 10/12 patients with MMN, while only a 3-9% of patients with ALS, CIDP, PNP and LMND presented antiganglioside antibodies.

CONCLUSIONS

Analysis of anti-GQ1b antibodies confirms the diagnosis of MFS, excluding other acute brainstem pathologies and, in this study, detection of anti-GD1a antibodies indicates axonal damage in GBS and suggest a worse prognosis. IgM anti-GM1 antibodies are only found in MMN. These findings confirm a disease specific correlation between specific neuropathies and antiganglioside antibodies clinically useful.

[Anti-GQ1b antibodies: usefulness of its detection for the diagnosis of Miller-Fisher syndrome]

BACKGROUND

To study the presence of anti-GQ1b antibodies as a tool for the diagnosis of Miller-Fisher syndrome (MFS).

PATIENTS AND METHOD

We studied 54 patients with probable diagnosis of MFS and 10 patients diagnosed as Guillain-Barré syndrome plus ophthalmoplegia (1 case), Bickerstaff's encephalitis (1 case), relapsing ophthalmoplegia (7 cases) and relapsing diplopia (1 case). Results were compared with 130 patients with other disimmune neuropathies. Antibodies were detected by ELISA and checked by thin layer chromatography. Campylobacter jejuni serology was studied using a complement fixation test.

RESULTS

Diagnosis of MFS was confirmed in 38 patients. A 97.3% were positive for GQ1b, being all negative for Campylobacter jejuni serology. A second test after 4-5 weeks of nadir was negative in 84.2% (16/19), concomitant with clinical recovery.

CONCLUSIONS

Anti-GQ1b antibodies are useful markers for the differential diagnosis of MFS, specially with some acute brainstem disorders. Testing must be performed during the first four weeks of clinical course. This correlation between the triad ataxia, arreflexia and ophthalmoplegia and anti-GQ1b antibodies confirms that they are highly specific of MFS.

Determination of the antihypertensive drug cilazapril and its active metabolite cilazaprilat in pharmaceuticals and urine by solid-phase extraction and high-performance liquid chromatography with photometric detection

A liquid chromatographic method with photometric detection for the determination of cilazapril and its active metabolite and degradation product cilazaprilat in urine and pharmaceuticals has been developed. The chromatographic method consisted of a microBondapak C18 column maintained at 30+/-0.2 degrees C, using a mixture of methanol-10 mM phosphoric acid (50:50 v/v) as mobile phase at a flow-rate of 1.0 ml/min. Enalapril maleate was used as internal standard. The detection was performed at a wavelength of 206 nm. A study of the retention of cilazapril and cilazaprilat using solid-liquid extraction has been carried out in order to optimise the clean-up procedure for urine samples, which consisted of a solid-liquid extraction using C(R) cartridges. Recoveries greater than 85% are obtained for both compounds. The method was sensitive, precise and accurate enough to be applied to the determination of urine samples obtained from three hypertensive patients up to 24 h after intake of a therapeutic dose (detection limit of 70 ng/ml for cilazapril and cilazaprilat in urine). A comparison of the method developed using photometric and amperometric detection has been carried out.

The role of clinical informatics in the Agency for Healthcare Research and Quality's efforts to improve patient safety

In 1998, the Institute of Medicine (IOM) issued a report on medical errors, which estimated that up to 98,000 people die in U.S. hospitals each year from errors. This report raised concerns that medical errors have become a national public health problem that should be addressed in the same manner as other epidemics such as heart disease, diabetes, and obesity. In 2001, the IOM released a follow-up report encompassing a broader range of quality issues. They concluded that the U.S. healthcare system is outmoded and incapable of providing consistent, high-quality care. They outlined a strategy for redesigning U.S. healthcare delivery to achieve safe, dependable, high-quality care, which emphasizes information technology as an integral part of the solution. AHRQ's fiscal year 2001 appropriation included an increase of $50 million dollars for initiatives to reduce medical errors and improve patient safety. AHRQ responded to this mandate by developing a series of research solicitations that form an integrated set of activities to design and test best practices for reducing errors in multiple health care settings. This paper discusses the components of this program and the central role of medical informatics research in the Agency's efforts to improve the safety of medical care in America.

Primary vaccination of infants with diphtheria-tetanus-acellular pertussis-hepatitis B virus- inactivated polio virus and Haemophilus influenzae type b vaccines given as either separate or mixed injections

OBJECTIVE

The aim of this open, multicenter, randomized trial was to evaluate the immunogenicity and reactogenicity of a candidate combined diphtheria-tetanus-acellular pertussis-hepatitis B virus-inactivated polio virus (DTaP-HBV-IPV) vaccine when given as either a mixed or as separate concomitant injections with Haemophilus influenzae type b (Hib) vaccine.

STUDY DESIGN

A total of 359 subjects were randomized to receive either DTaP-HBV-IPV/Hib (mixed administration - 180 subjects) or DTaP-HBV-IPV + Hib (separate administration in opposite limbs - 179 subjects) at 2, 3, and 4 months of age.

RESULTS

After vaccination, seroprotective antibody concentrations against diphtheria, tetanus, hepatitis B, and polio viruses and a high (> or = 97%) pertussis vaccine response were seen in almost all study participants. All subjects except one in the mixed administration group had postvaccination Hib anti-PRP antibody concentrations > or = 0.15 microg/mL. Of subjects in the mixed and separate group, 77.2% (geometric mean antibody concentration, 2. 62 microg/mL) and 88.6% (geometric mean antibody concentration, 4.45 microg/mL) had Hib anti-PRP concentrations > or = 1 microg/mL, respectively. The addition of the Hib component to the 5-component vaccine did not increase the incidence of local or general reactions.

CONCLUSION

Both administrations of the candidate vaccine were found to be safe, immunogenic, and well tolerated. Although anti-PRP geometric mean antibody concentrations and the percent of subjects achieving the 1 microg/mL seroprotective level were lower after the mixed administration, they were in the range seen with monovalent Hib vaccines or with other DTaP-based/Hib combinations licensed in some European countries. Therefore both administrations have the potential to simplify childhood immunization.

Quality Enhancement Research Initiative for human immunodeficiency virus/acquired immunodeficiency syndrome: framework and plan. HIV-QUERI Executive Committee

The Veterans Health Administration (VHA) sees approximately equal to 17,000 human immunodeficiency virus (HIV)-infected patients each year, which makes it the largest provider of HIV care in the United States. HIV causes chronic progressive disease that leads to early death. Newer combination antiretro viral treatments are effective but expensive and difficult to use. The HIV Quality Enhancement Research Initiative (HIV-QUERI) uses the QUERI process to identify high-risk and high-volume populations (step 1), which includes those already under VHA care for HIV, those who do not know of their infection, and those at risk for HIV. In identifying best practices (step 2), the HIV-QUERI will benefit greatly from existing guidelines for the care of established HIV infection, but gaps in knowledge regarding adherence to medication regimens and cost-effective screening are large. To identify existing practice patterns (step 3), the HIV-QUERI will develop a clean analytic data set based on Immunology Case Registry files and expand it through a survey of veterans. Interventions to improve care (step 4) will include national, regional, and site-specific feedback on performance relative to quality standards, as well as patient-level and provider-level interventions to improve adherence and support medical decision-making. To document that best practices improve outcomes and quality of life (steps 5 and 6), HIV-QUERI will track indicators on an ongoing basis by use of the Immunology Case Registry database and possible future waves of the survey. In addition, we will require that these issues be addressed in evaluations of HIV-QUERI interventions. In the present article, we present these steps within a framework and plan.

Routine use of anaerobic blood cultures: are they still indicated?

PURPOSE

To determine the number of patients with bacteremia and fungemia and to evaluate the utility of routine anaerobic blood cultures as part of the work-up for suspected bacteremia.

SUBJECTS AND METHODS

Retrospective review of microbiology data followed by selective chart review at a university-affiliated Veterans Affairs Medical Center. We determined the number of bacterial blood cultures drawn from January 1, 1994, to December 31, 1996, and the number of anaerobic, aerobic, and fungal isolates. Chart reviews were then performed on all patients with a positive anaerobic result.

RESULTS

There were 6,891 sets of blood cultures processed through the laboratory, yielding 1,626 patients with positive results. Anaerobic isolates were recovered from 36 patients (2.2%) in 48 bottles. Aerobic isolates were recovered from 1550 patients (95.3%), and fungal isolates were recovered from 40 patients (2.5%). Seven patients (0.4%) had true anaerobic bacteremia. All seven patients had an obvious source of anaerobic infection that was known or suspected before the cultures were drawn. Antibiotic changes were made in four of these patients after the positive anaerobic results were known. Antibiotic changes led to clinical improvement in one patient.

CONCLUSIONS

Routine use of anaerobic blood cultures rarely results in clinically important diagnostic or therapeutic benefits, based on the low incidence of anaerobic bacteremia in patients who are not at increased risk. Anaerobic blood cultures should be selectively ordered in patients at risk for anaerobic infections.

Repeated sequences in bacterial chromosomes and plasmids: a glimpse from sequenced genomes

To gain insight into the extent of exact DNA repeats in sequenced bacterial genomes and their plasmids, we analyzed the collection of completely sequenced bacterial genomes available at GenBank using the program Miropeats. This program draws graphical representations of exact DNA repeats in whole genomes. In this work, we present maps showing the extent and type (inverted or direct) of exact DNA repeats longer than 300 bp for the whole collection. These repeats may participate in a variety of events relevant for bacterial genome plasticity, such as amplifications, deletions, inversions, and translocations (via homologous recombination), as well as transposition. Additionally, we review recent data showing that high-frequency architectural variations in genomic structure occur at both the interspecies and interstrain levels.

Particulate Air Pollution in Mexico City: A Collaborative Research Project

PM₁₀, PM₂₅, precursor gas, and upper-air meteorological measurements were taken in Mexico City, Mexico, from February 23 to March 22, 1997, to understand concentrations and chemical compositions of the city's particulate matter (PM). Average 24-hr PM₁₀ concentrations over the period of study at the core sites in the city were 75 H g/m³. The 24-hr standard of 150 μ g/m³ was exceeded for seven samples taken during the study period; the maximum 24-hr concentration measured was 542 μ g/m³. Nearly half of the PM₁₀ was composed of fugitive dust from roadways, construction, and bare land. About 50% of the PM₁₀ consisted of PM_2.5, with higher percentages during the morning hours. Organic and black carbon constituted up to half of the PM_2.5. PM concentrations were highest during the early morning and after sunset, when the mixed layers were shallow. Meteorological measurements taken during the field campaign show that on most days air was transported out of the Mexico City basin during the afternoon with little day-to-day carryover.

Duration of efficacy of Ty21a, attenuated Salmonella typhi live oral vaccine

Currently, two different formulations of Ty21a live oral typhoid vaccine are commercialized. The enteric-coated capsule formulation was licensed based on results of three years of follow-up of a randomized, placebo-controlled, double-blind field trial in Area Occidente, Santiago, Chile, which demonstrated that three doses of this formulation, given on an every other day immunization schedule, conferred the best protection among several options evaluated. Subsequently, a liquid formulation (lyophilized vaccine organisms reconstituted with buffer and water into a vaccine cocktail) was commercialized after it was shown to provide superior protection than enteric-coated capsules over three years of follow-up in a randomized, placebo-controlled field trial in Area Sur Oriente and Area Norte, Santiago. Surveillance in the Area Occidente trial was continued for four additional years (i.e., total seven years of follow-up) and in the Area Sur Oriente/Area Norte trial for two additional years (i.e., a total of five years of follow-up). These additional surveillance data, which were analyzed to ascertain the longevity of protection conferred by these formulations of Ty21a, revealed that three doses of Ty21a in enteric-coated capsules (every other day schedule) conferred 67% protection over three years and 62% protection over seven years of follow-up, whereas three doses of liquid formulation (every other day schedule) elicited 77% protection over three years and 78% over five years of follow-up. Based on its excellent clinical acceptability, ease of oral administration, proven practicality in school-based mass immunization, and long-term efficacy enduring at least seven years, it is proposed that school-based immunization with Ty21a be utilized as a control measure in areas where the incidence of typhoid fever is high and Salmonella typhi are antibiotic-resistant.

Quantitative determination of indapamide in pharmaceuticals and urine by high-performance liquid chromatography with amperometric detection

A high-performance liquid chromatographic method with amperometric detection for the determination of the diuretic indapamide using a muBondapak C18 column is developed. The mobile phase consists of an acetonitrile-water mixture (45:55, 5 mM) in KH2PO4-K2HPO4 (pH 4.0). The compound is monitored at +1200 mV with an amperometric detector equipped with a glassy carbon working electrode. A liquid-liquid or solid-liquid extraction is performed prior to chromatographic analysis to avoid the interferences found in urine matrix. Percentages of recovery are 88.3 +/- 5.6 and 82.9 +/- 7.8 for liquid-liquid and solid-liquid extraction, respectively. The developed method has a linear concentration range from 25 to 315 ng/mL with a reproducibility in terms of relative standard deviation of 4% for a concentration level of 0.5 microgram/mL and a quantitation limit of 1 ng/mL. The method is applied to the determination of indapamide in tablets and urine obtained from hypertensive patients after the ingestion of Tertensif (indapamide 2.5 mg).

Vinorelbine and paclitaxel as first-line chemotherapy in metastatic breast cancer

PURPOSE

To evaluate the efficacy and toxicity of a combination of vinorelbine (VNB) and paclitaxel (PTX) as first-line chemotherapy in metastatic breast carcinoma (MBC).

PATIENTS AND METHODS

Between August 1995 and August 1997, 49 patients with untreated MBC received a regimen that consisted of VNB 30 mg/m2 in a 20-minute intravenous (IV) infusion on days 1 and 8 and PTX 135 mg/m2 in a 3-hour IV infusion (starting 1 hour after VNB) on day 1. Cycles were repeated every 28 days. The median age of the patients was 52 years, and 59% of patients were postmenopausal. Median performance status was 1. Dominant sites of disease were soft tissue in 6%, bone in 29%, and viscera in 65%.

RESULTS

Objective responses were recorded in 27 of 45 assessable patients (60%; 95% confidence interval, 46% to 74%). Complete remissions occurred in three patients (7%), and partial remissions occurred in 24 patients (53%). No change was recorded in 12 patients (27%), and progressive disease occurred in six patients (13%). The median time to treatment failure was 7 months, and median survival duration was 17 months. The limiting toxicity was myelosuppression, mainly leukopenia in 49 patients (100%) (grade 1 to grade 2, four patients; grade 3, 30 patients; and grade 4, 15 patients). Neutropenia was observed in 100% of patients (grade 1 to grade 2, three patients; grade 3, 11 patients; grade 4, 35 patients). Two treatment-related deaths due to febrile neutropenia were observed in patients with massive liver involvement. Peripheral neurotoxicity developed in 33 patients (67%) (grade 1, 25 patients; grade 2, eight patients); there were no grade 3 or grade 4 episodes.

CONCLUSION

The combination of VNB-PTX showed significant activity as first-line chemotherapy for patients with MBC. Myelosuppression was the dose-limiting side effect, whereas neurotoxicity was mild to moderate.

PNA molecular beacons for rapid detection of PCR amplicons

The authors have developed a method for rapid detection of polymerase chain reaction (PCR) amplicons based on surface immobilized PNA-DNA hybrid probes ('molecular beacons') that undergo a fluorescent-linked conformational change in the presence of a complementary DNA target. Amplicons can be detected by simply adding a PCR reaction to a microtitre-well containing the previously immobilized probe, and reading the generated fluorescence. No further transfers or washing steps are involved. The authors demonstrate the specificity of the method for the detection of ribosomal DNA from Entamoeba histolytica.

[Cerebral hemorrhage in Sneddon syndrome]

INTRODUCTION

Sneddon syndrome is the association of livedo retricularis and cerebrovascular lesions. It is a vasculopathy of vessels of small and medium calibre which affects young people and is of unknown origin. It is often associated with arterial hypertension and repeated ischemic cerebrovascular accidents which lead to intellectual deterioration.

CLINICAL CASE

We describe a 49 year old man who, from the age of 23, had had repeated transient or established episodes compatible with ischemic cerebrovascular accidents. These were followed by various neurological sequelae and by intellectual deterioration. Finally he died of a cerebral hemorrhage whilst on anticoagulant treatment with Synthron. We show the neuroimaging findings (CT, MR and angiography) and the neuropathological studies (cerebral hemorrhage, fibrosis of the intima of the vessels of the circle of Willis, absence of inflammation, bilateral unsymmetrical leukoencephalopathy of the cerebral hemispheres and multiple cortical infarcts).

CONCLUSION

We wish to draw attention to the occurrence of this complication, its possible relationship to the vasculopathy mentioned, bursting of one of the arteries of the revascularization complex, arterial hypertension or anticoagulant treatment, and also to add one more case to the few described as having hemorrhage and neuropathology in Sneddon syndrome.

[Medical care costs for HIV-positive and AIDS patients in four hospitals in Santiago, Chile]

BACKGROUND

Medical care of HIV infected and AIDS patients may represent an important economical burden for public hospitals.

AIM

To assess direct and indirect costs of medical care for HIV infected and AIDS patients in public hospitals of the Metropolitan Region of Chile.

MATERIAL AND METHODS

Between August 1994 and February 1995, information about outpatient and hospitalized medical care of 417 HIV infected patients was gathered (representing approximately 16% of the seropositive population). Patients were divided as having or not having AIDS. The latter were those included in groups I, II, III and category C2 of group C (group 4). The cost of medications, procedures and examinations of these patients was calculated.

RESULTS

Thirty six percent of studied patients had AIDS. The annual cost of care for AIDS patients was US$3760 compared to US$1450 for HIV infected patients without AIDS. Medications represented 75% and 65% of total costs in patients with and without AIDS respectively. The figures for examinations and procedures were 17% and 22% and for medical attentions were 7.5% and 8.8% respectively.

CONCLUSIONS

Medical care of patients with AIDS has higher costs than that of HIV infected patients without AIDS. Thus, the retardation of the progression of the disease would have social, humanitarian and economical benefits. Our costs are similar to those of other countries with a similar level of economic development.