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Biomedical subjects

A Loría

Publications and source records attributed to A Loría.

63 records · Page 4Linked to original sources
PubMedDate not supplied

[Chemico-clinical permanent program of the NIH. I. The first phase of the program].

BACKGROUND INFORMATION: This is the report of the first phase of an internal/external permanent program of the MNIH (Mexican National Institutes of Health). The permanent program evolved from a previous one operating from 1984 to 1988 in the MNIH (Refs 1-5). OBJECTIVE: To evaluate the precision of the assay systems used currently by the clinical chemistry laboratories of the MNIH. MATERIAL AND METHODS: A single batch of a lyophylized control serum prepared for the program by an agency of the Ministry of Health was used throughout the study. During a period of four months, the participants were provided with flasks of the control serum every two weeks to assay the analytes included in the routine daily work of each laboratory. They also received every two weeks an update of the mean of means and interlab CV of the information available. RESULTS: The 11 participants reported 6278 results of 24 analytes (6 enzymes, 8 electrolytes and 10 organic metabolites) assayed in 179 systems. The majority of the systems (162/179 = 91%) were autoanalyzers. There were 168 systems which could be evaluated in precision and 115 in accuracy. The rate of imprecision was 15% (25/168) and of inaccuracy 17% (19/115). CONCLUSIONS: 1. The participants were able to act as a reference group to assign the value of 12 analytes in a control serum with low concentration of most analytes. 2. Imprecision was concentrated in two participants (Labs B and J with 15 of the 25 imprecisions: see table 2). The second phase of the program will be to identify and if possible eliminate the sources of variation in the systems of participants B and J.

Blood Chemical Analysis↗
PubMedDate not supplied

[Evaluation of Mexican biomedical journals].

We present the evaluation procedures of Biomedical Journals, performed by the Journal Committee of the Centro Nacional de Información y Documentación sobre Salud (CENIDS) for the preparation of CR-ROM ARTEMISA 2 (Edited health information articles in Mexico), which contains a database of the complete text of articles appearing in the journals of the highest quality published in Mexico.

Evaluation Studies as Topic↗
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[Coverage of Mexican articles and journals in the database Bibliomex Salud].

OBJECTIVE: To evaluate the coverage of Mexican journals and manuscripts of biomedical research in a Mexican data base (Bibliomex Salud) during its 10 years of existence (1985-1994). MATERIAL AND METHODS: All the manuscripts published by a single Mexican journal Revista de Investigación Clínica (RIC) were searched for in Bibliomex: the absence of a RIC manuscript in Bibliomex was considered a failure. Also, the number and identity of the Mexican journals included in Bibliomex was also noted. From a total of 744 manuscripts 99 were excluded (22 non-Mexican, 25 nonindexable, and 52 initially not indexed by Bibliomex). The remainder (645) were classified according to starting year of indexing: originals since the first year; letters to the editor since 1990; and editorials and authors' replies since 1993. RESULTS: Bibliomex started out with 21 Mexican journals and now has more than 50 (12 indexed during the 10 years, 27 for the last 5-9 years, and 16 for the last 1-4 years). Regarding manuscripts, Bibliomex had an 8% failure rate in originals (46/597) and letters (3/36), and 25% in editorials and authors' replies (3/12). CONCLUSIONS: a) The coverage of Bibliomex has improved in its second half of life in the number of both journals and manuscripts indexed; b) the retrieval of information could be improved by two changes in the procedures of Bibliomex; c) Bibliomex seems to be a database which could be used to analyze Mexican research production at several levels (institutional, regional, and national).

Information Systems↗
PubMedDate not supplied

[Evaluation of pipetting systems. III. Micropipette precision in a routine task].

OBJECTIVE: To establish a norm of the precision achievable with a micropipette in an IRMA assay under routine conditions. MATERIAL AND METHODS: A micropipette (Gilson) adjusted to dispense 100 microL was used by a single analyst with experience in its use. In each assay, ten aliquots of radioactive antiprolactin were pipetted in clean tubes (PRE-batch tubes), followed by pipetting of the tubes being processed in the assay, and at the end, a second pipetting of 10 aliquots in clean tubes (POST-batch tubes). The study includes the data of 15 consecutive batches during a seven month period with an overall mean of 283 tubes per batch. The PRE- and POST-tubes were read in a gamma counter (Crystal plus). The mean, SD and CV for PRE, POST and global (PRE+POST) tubes were calculated for each batch. RESULTS: The global CV of the 15 batches ranged from 1.6 to 6.9%, mean of 3.1%. We found no evidence of increased imprecision due to fatigue of the analyst, but surprisingly, we observed that in nine of the 15 batches there was a significant difference in the means of the PRE-tubes vs the POST-tubes (t test) without differences in precision. Thus, part of the global variability is due to what we have called pseudoimprecision (i.e. an increase in CV due to differences in means). In addition, the POST-tubes had higher values in the first 7 batches but the opposite occurred in the last 8 batches (table 2). This shift in the sign of the PRE-POST differences suggests the presence of opposite factors operating in time, i.e. one or more factors increased the volume of pipetting after using the pipette more than 150 times (batches 1-7) whereas other/others decreased it (batches 8-15). CONCLUSIONS: 1. Our first approximation to a norm of micropipetting precision in batches of 200-300 tubes was a CV of 3.1%. 2. This norm was influenced by a problem of pseudoimprecision detected ex-post-facto. 3. Our findings justify continuation studies to detect the pseudoimprecision and evaluate its causes prospectively.

Antibodies↗
PubMedDate not supplied

Diagnostic concordance in biopsies of deceptive prostatic carcinoma.

OBJECTIVE: To explore the diagnostic concordancy of surgery pathologists in deceptive prostatic carcinoma biopsies (DPCs) purposely selected as of difficult interpretation. SETTING: Ten experienced pathologists belonging to five tertiary care centers in Mexico City participated. MATERIAL AND METHODS: A total of 25 slides (16 DPCs and 9 benign biopsies) were marked and circulated among the participants. They were asked to classify each slide in one of five categories ranging from carcinoma to benign hyperplasia using the criteria of Epstein. The 16 DPCs had been confirmed by immunohistochemistry studies and by review of two expert uropathologists from the MD Anderson Medical Center in Houston TX. A weighted kappa was use to evaluate the concordancy of the pathologists. RESULTS: The concordancy with the experts opinion ranged from substantial in one pathologist (KW = 0.77) to bad in another (KW = -0.07) and the mean kappa was 0.32. In two of the three institutions with more than one pathologist, the intrainstitucional concordancy improved (KW of 0.57-0.64). The pathologists were unable to reach a consensus (7 or more agreeing) in 12 of the 25 slides. Overall, 12% of the diagnosis were considered uncertain, 29% were incorrect (45% of DPCs and 19% of benign) and only 59% were correct (55% of DPCs and 67% of benign). CONCLUSION: Efforts should be made to improve the diagnostic accuracy of pathologists in DPCs.

Adenocarcinoma↗
PubMedDate not supplied

[What is known about micronutrients in Mexico].

OBJECTIVE: To update the information on micronutrients in Mexico regarding: 1. The research lines according to priority of the micronutrient, subjects affected, and its focus (basic, clinical, epidemiological, operational). 2. The laboratory capacity available for micronutrient assays. MATERIAL AND METHODS: We analyzed review articles of what has been published on micronutrients in Mexico since 1950. We also gathered information by questionnaire from the 16 research groups working in Mexico in the area of micronutrients. RESULTS: We generated tables summarizing the situation of the six micronutrients which we identified as the most problematic in Mexico (vitamins A and C, and iron, iodine, zinc and calcium). CONCLUSIONS: We reached 10 conclusions related to populations of study, research line priorities, and desirable operational studies.

Adult↗
PubMedDate not supplied

[Anemia and iron deficiency in 490 Mexican pregnant women].

OBJECTIVE: To explore correlations of sociobiological variables with levels of blood hemoglobin (HB) in 490 pregnant women. SETTING: Women attending private practice and two public hospitals in the city of Leon, State of Guanajuato (1800 m above sea level). MATERIAL AND METHODS: Demographic, obstetric, nutritional and socioeconomic data were obtained together with an EDTA-blood sample for CBC, and serum for metabolite assays. The women had a mean gestation of 25 weeks (range 4-40) and 65% were multiparous with a mean parity of 2.1. By Mexican standards they had fairly high social, nutritional and intergenesic lapse. Associations were explored by step-wise multiple ANOVA. RESULTS: On the basis of HB < 12 g/dL (equivalent aprox to 11 at sea level), 37% of the women were considered anemic. The MANOVA (excluding iron deficiency) showed associations of HB with gestation (p < 0.001) and parity (p = 0.024). Iron deficiency was present in 76% of the anemics (136/180) and 31% of the non-anemics (97/310). Folate and vitamin B12 assays in women with anemia and no iron deficiency showed folate or B12 deficiency in only 33% (14/43) leaving 29 cases with anemia of unknown etiology. CONCLUSIONS: 1. Gestation age was the factor most strongly associated to anemia and iron deficiency in our sample. 2. Anemia and iron deficiency were seen in 37% (N = 180) and 48% (N = 233) of the women respectively. 3. Of the 180 anemic women, 76% (N = 136) were iron deficient but only 14/43 anemic without iron deficiency were folate or B12 deficient leaving 6% (29/490) with anemia of unknown etiology. 4. The prevalence of anemia and iron deficiency were high in our population in spite of its fairly good sociodemographic and nutritional conditions.

Adolescent↗
PubMedDate not supplied

[First two years of an external quality assurance program for urinalysis].

OBJECTIVE: To analyze the first two years of a strip uroanalysis quality assurance scheme operating in Mexico. METHODS: The participants received 8 shipments of four controls each as dried tablets to be dissolved and analyzed with urine strips. The number of participants increased from < 50 in the 1st shipment to > 200 in the 8th. They assayed 6-10 analytes depending on the strip used and sent in 763 reports. For each report we calculated a score per analyte (n = 4), per shipment (n = 24 to 40) and a global score in the 8 shipments (n = 707 to 763 reports). The scores ranged from zero (excellent accuracy) to a maximum of 400 and were calculated by comparison with the modal value of about 600 American and Canadian laboratories which assayed the same controls using exclusively Bayer strips and instrumental readings. RESULTS: The best score was for nitrites (global score of 3 in 741 reports) and the worst for specific gravity (58 in 744 reports); the other analytes had scores from 11 to 19 (Table 1). The scores of four types of methods (Table 2) showed the best results with Bayer strips and instrumental readings (score of 13 in 469 reports) and the worst with strips of other suppliers (scores of 28 for visual and 31 for instrumental readings) and intermediate with visual readings of Bayer strips (score of 21). CONCLUSIONS: 1. Our results led us to the decision to exclude from the program participants who do not use Bayer strips as our program may disorient them instead of helping to improve their assays. 2. We confirmed that instrumental readings perform better than visual readings. 3. The causes of suboptimal performance in specific gravity need to be explored.

Humans↗