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In this study, sex ratio, spawning season, fork length (L(F)) at maturity (L(F50)), batch fecundity and spawning frequency were characterized for the continental population of Ocyurus chrysurus from the Campeche Bank, in the southern Gulf of Mexico. A total of 1657 specimens were collected from February 2008 to January 2009. The overall sex ratio (male:female) and sex ratios by size-class showed no significant differences from an expected 1:1 ratio. The Campeche Bank population did not conform to the reproductive seasonality pattern characteristic of a continental population. A protracted spawning season that extended from January to September with peaks occurring mainly between April and May and additionally in September was observed. The population conformed, however, to the sexual maturity pattern observed for populations and species associated with a continental margin. Fish of both sexes reached the onset of sexual maturity at a similar and small L(F) of c. 14 cm, and L(F50) (L(F) at which 50% of females and males become mature) was 21·3 and 19·4 cm. Asynchronous-type ovarian development was observed for this species and batch fecundity estimates ranged from 14,102 to 164,756 oocytes (mean ±S.D. = 43,852 ± 32,684 oocytes). The overall spawning frequency estimate was once every 8·3 days or 26 times during the 9 month spawning season.

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1. The aim of the present study was to investigate the role of dopamine (DA) in the hypotensive and renal effects of L-arginine during extracellular fluid volume expansion (10% bodyweight). 2. Animals were randomized to non-expanded and expanded groups. Both groups received different treatments: L-arginine (250 mg/kg, i.v.), N(G)-nitro-L-arginine methyl ester (L-NAME; 1 mg/kg, i.v.), haloperidol (3 mg/kg, i.p.) and L-arginine + haloperidol (n = 8). Mean arterial pressure (MAP), diuresis, natriuresis, kaliuresis, glomerular filtration rate, renal plasma flow (RPF) and nitrite and nitrate (NO(x)) excretion were determined. 3. The increase in MAP induced by L-NAME was greater in expanded than in non-expanded rats (42 +/- 3 vs 32 +/- 3 mmHg, respectively; P < 0.01). Administration of haloperidol did not modify the L-arginine hypotensive effect. 4. Blockade of nitric oxide synthase diminished urine flow in non-expanded (4.15 +/- 0.56 vs 0.55 +/- 0.11 microL/min per 100 g; P < 0.01) and expanded animals (24.42 +/- 3.67 vs 17.85 +/- 2.16 microL/min per 100 g; P < 0.01). Diuresis induced by L-arginine was reduced by DA blockade in both non-expanded (17.15 +/- 2.11 vs 6.82 +/- 0.61 microL/min per 100 g; P < 0.01) and expanded animals (44.26 +/- 8.45 vs 25.43 +/- 5.12 microL/min per 100 g; P < 0.01). 5. Sodium excretion decreased with L-NAME treatment in non-expanded (0.22 +/- 0.03 vs 0.06 +/- 0.01 microEq/min per 100 g; P < 0.01) and expanded animals (3.72 +/- 0.70 vs 1.89 +/- 0.23 microEq/min per 100 g; P < 0.01). Natriuresis induced by L-arginine was diminished by haloperidol both in non-expanded (0.94 +/- 0.13 vs 0.43 +/- 0.04 microEq/min per 100 g; P < 0.01) and expanded rats (12.77 +/- 0.05 vs 3.53 +/- 0.75 microEq/min per 100 g; P < 0.01). Changes in kaliuresis changes seen following treatment with L-arginine, L-NAME and L-arginine + haloperidol followed a pattern similar to that observed for sodium excretion in both groups of rats. 6. L-arginine enhanced RPF in non-expanded animals (11.96 +/- 0.81 vs 14.52 +/- 1.05 mL/min per 100 g; P < 0.01). Glomerular filtration rate was increased by extracellular volume expansion (3.08 +/- 0.28 vs 5.42 +/- 0.46 mL/min per 100 g; P < 0.01). 7. The increase in NOx induced by acute volume expansion (0.18 +/- 0.03 vs 0.52 +/- 0.08 nmol/min per 100 g; P < 0.01) was diminished following the administration of haloperidol (0.52 +/- 0.08 vs 0.26 +/- 0.06 nmol/min per 100 g; P < 0.01). 8. Although DA does not participate in the actions of nitric oxide on vascular tone, both systems would play an important role in renal function adaptation during extracellular fluid volume expansion.

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OBJECTIVE: To explore trends in mother-child healthcare (MCHC) research over the past 30 years. METHODS: Classifications of Medline articles were made at 5-year intervals using Medical Subject Headings (MeSH) as classifiers. Papers were classified in mutually and non-mutually exclusive categories by subject (mother and four age groups of children) and type of research (clinical, basic, epidemiologic, and unclassified) and its various combinations. RESULTS: The number of MCHC papers increased from 34,110 in 1966 to 65,028 in 1995, but the proportion of all Medline articles (18-21%) was relatively stable. There were remarkable long-term temporal stabilities in the proportions of MCHC papers of mothers and the four age groups of children. Most papers dealt with child (46%) and adolescents (45%), and only 11% studied mother and children together. Regression analysis indicated that a linear increase in number of MCHC papers in Medline (1053/year) was represented largely by single-age and combinations of age children, especially adolescence. However, the slope for mother-plus-children papers (113/year) was substantially higher than for mothers alone (64/year). Clinical papers (52%) were the dominant type of MCHC research, but the proportions of basic and epidemiologic papers and their combinations with clinical papers have increased substantially in the past decade. CONCLUSIONS: There has been a dominance of clinical and child-related papers in MCHC research, which may be a reflection of restricted outlooks of specialists in the area. This may change soon if the tendency toward increasing numbers of basic and epidemiologic papers holds.

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BACKGROUND: Some studies performed in developed countries with caucasian population have suggested an increase in the frequency of primary gastric lymphoma (PGL) in the past two decades. OBJECTIVE: To establish the frequency of PGL in two National Institutes of Health in Mexico in an interval of 18 years. METHODS: We reviewed 1,854 gastric malignant neoplasms diagnosed between 1979-1996 in mestizo patients seen at two different institutions. One of them (INC) is an oncological hospital, whereas the other one (INN) is a general hospital which treats patients with benign as well as malignant gastrointestinal diseases. RESULTS: A hundred and sixty three (8.8%) gastric lymphomas were identified from 1,854 gastric malignant tumors. The incidence of PGL showed a two to three-fold increase in the last years of the study in both institutions. The increased frequency was highly significant when compared to the initial rate. This increase does not appear to be due to patient selection criteria nor to the number of malignant gastric tumors in our institutions. CONCLUSIONS: Our results indicate an increased frequency of PGL the patient population of two National Institutes of Health in Mexico during the last years. Additional studies are necessary in order to define in the increase in PGL is limited to certain geographical areas or ethnic groups.

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OBJECTIVE: 1. To estimate the prevalence of pre-obesity and obesity in a 1992 to 1993 national survey of the Mexican urban adult population. 2. To compare our findings with other national surveys and with data for Mexican Americans. RESEARCH METHODS AND PROCEDURES: The national representative sample of the Mexican urban adult population included 8462 women and 5929 men aged 20 to 69 years from 417 towns of >2500 people. Body mass index (BMI), calculated from measured weight and height, was classified using the World Health Organization categories of underweight (BMI < 18.5 kg/m2), normal weight (BMI 18.5 to 24.9 kg/m2), pre-obesity (PreOB = BMI 25 to 29.9 kg/m2) and obesity (OB = BMI 30+ kg/m2). Estimates for Mexican Americans were calculated from U.S. survey data. RESULTS: Overall, 38% of the Mexican urban adult population were classified as pre-obese and 21% as obese. Men had a higher prevalence of pre-obesity than women did at all ages, but women had higher values of obesity. Both pre-obesity and obesity increased with age up to the age range brackets of 40 to 49 or 50 to 59 years for both men and women. Both pre-obesity and obesity prevalence estimates were remarkably similar to data for Mexican Americans from 1982 through 1984. Comparison with other large surveys showed that countries differed more in the prevalence of obesity than of pre-obesity, leading to differences in the PreOB/OB ratio, and that countries also differed in the gender ratio (female/male) for both pre-obesity and obesity. DISCUSSION: Pre-obesity and obesity were high in our population and increased with age. Our approach of characterizing large surveys by PreOB/OB and gender ratios appeared promising.

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OBJECTIVE: To provide an evaluation model of internal accuracy illustrating its use in a quality control program of clinical chemistry. METHODS: The model uses data transformed to percentage of assigned value (%AV) that allows the pooling of different controls. Precision is evaluated by the mean of the intracontrol coefficients of variation, and accuracy by the mean of means of the %VAs and its standard deviation. The model was used in 17,280 measurements of 23 analytes assayed in seven pairs of controls (medium and high concentration) during four years in two automated clinical chemistry analyzers. RESULTS: The model established inaccuracy of 5% to 25% in seven analytes, five of them enzymes. It also detected interanalyzer differences in accuracy of five analytes (22%) and an erroneous assigned value in 19 of 304 controls (6%). CONCLUSIONS: The model showed its capacity to dissect the sources of variation of accuracy. There was inaccuracy in 30% of the analytes but further studies are needed to validate these inaccuracies with controls of other sources. The model can be useful for control programs of any quantitative assay system. A summary description of the model's operation is given.

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OBJECTIVE: To evaluate an internal-external quality control program of four automated counters. METHODS: Every one or two weeks during 14 months, six direct cell parameters were measured in three fresh blood samples in four Coulter counters. The median per parameter of the working day was used to detect inaccuracies and if the participants' internal control program confirmed it, a recalibration of the parameter was performed. RESULTS: In 21 of 22 instances, the internal program confirmed an inaccuracy and a recalibration was done (4 leukocyte and 5 erythrocyte counts, 5 hemoglobins, 7 red-cell volumes). In these four parameters there were no large differences between the lowest and highest counter upon analyzing all results whereas all counters differed from one another in the parameters that cannot be recalibrated by the user (platelet volume, red-cell distribution width). CONCLUSIONS: 1. The program contributed to good accuracy and precision within-counters and good concordancy between-counters in the parameters that can be recalibrated. 2. The counter differences in red-cell distribution width were sufficiently large (up to 9%) to affect clinical interpretation. This poses the need of width distribution reference ranges for each counter.

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The purpose of this work is to estimate the prevalence of hypertension in the urban population of Mexico. We studied a multistage national sample representative of the urban population in 417 cities of over 2500 people. The blood pressure of 14 657 individuals (6053 men and 8604 women) aged 20-69 years was measured after a 5-min rest using a standard mercury sphygmomanometer. The survey personnel had been previously trained and standardised. The main results show a crude prevalence of hypertension, as defined by the JNC VI, of 28.1% in women and 37.5% in men (27.2% and 37.1% age-adjusted). Both genders exhibited a trend of increasing hypertension with age. In individuals under 50 years of age, women had lower rates than men, but the difference disappeared in the older groups. The awareness of hypertension (28%) as well as the success of treatment (22%) were low in our sample. Our results had more similarities than differences with respect to those observed in other national surveys. It is concluded that hypertension in Mexico is an important public health problem similar to that seen in developing and developed nations. Efforts should be aimed at strengthening measures to prevent and control hypertension in Mexico. More information is needed of the sort obtained from longitudinal studies.

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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.

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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.

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OBJECTIVE: To report a case of gastrointestinal bleeding due to a blue rubber bleb nevus syndrome undiagnosed for 21 years. CASE: A woman of 28 years of age suffered chronic gastrointestinal bleeding starting at seven years of age. During these 21 years she received various treatment with oral and parenteral iron and, in addition, four blood transfusions. We found her to be anemic with 7.8 g/dL of hemoglobin (HB), iron deficient and with skin lesions in tongue, right hand and lower extremities. A skin biopsy diagnosed the lesions as cavernous hemangiomas. Multiple intestinal hemangiomas seen by radiologic, endoscopic and colonoscopic studies, established the diagnosis. She was treated with oral iron; three months later she was asymptomatic and with higher levels of HB (9.1 g/dL). CONCLUSION: The rarity of the syndrome and the fact that, as far as we know, it is the first case reported in Mexico, probably led to a delay in its diagnosis and to potentially dangerous therapy in this patient in spite of the fact that the diagnosis was not difficult.

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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.

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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.

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Objetivo. Evaluar la cobertura de artículos y revistas médicas mexicanas durante los 10 años de existencia de la base de datos mexicana Bibliomex Salud. Material y métodos. Se analizó si los artículos publicados por la Revista de Investigación Clínica (RIC) fueron registrados por Bibliomex: la ausencia de un manuscrito RIC en Bibliomex se consideró una falla por omisión. Se recuperó la identidad de las revistas mexicanas capturadas en dicho lapso. Del total de 744 manuscritos, se excluyeron 99 (22 extranjeros, 25 no referenciables y 52 inicialmente no capturados por Bibliomex). El remanente de 645 manuscritos se clasificó de acuerdo con el año en que comenzaron a registrarse: originales desde el inicio, cartas a los editores a partir de 1990, editoriales y respuestas a cartas a partir de 1993. Resultados. Bibliomex inició con 21 revistas mexicanas y actualmente captura más de 50 (12 durante los 10 años, y 27 en los últimos cinco a nueve años); tuvo 8 por ciento de omisiones en originales (46/597) y cartas (3/36) y 25 por ciento en editoriales y respuestas (3/12). Conclusiones: a) Ha mejorado sensiblemente la cobertura de Bibliomex en la segunda mitad de su vida tanto en manuscritos como en revistas: b) el uso de la información publicada por Bibliomex podría mejorarse con dos modificaciones de su proceso operativo; c) Bibliomex parece ser actualmente una base de datos adecuada para recabar información de producción biomédica mexicana que pudiera publicar periódicamente algún organismo interesado

Objetive. 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 (RIG) 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 non-indexable, 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).

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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).

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