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Biomedical subjects

M Hurtado

Publications and source records attributed to M Hurtado.

At least 19 recordsLinked to original sources
PubMed2006

Comparison of three microtube column agglutination systems for antibody screening: DG Gel, DiaMed-ID and Ortho BioVue.

The aims of the present study were to evaluate the estimated diagnostic accuracy of a new microtube column agglutination system (DG Gel, Diagnostic Grifols, Barcelona, Spain), to analyse the antibody reactivity and to compare the data with the two well-established DiaMed-ID and Ortho BioVue systems. We collected 3024 consecutive samples from blood donors, transfusion recipients and pregnant women, and 100 samples containing antibodies of known specificity. All these samples were tested in parallel by the three microtube agglutination systems. The estimated sensitivity was 100% for DG Gel and Ortho BioVue and 97.58% for DiaMed-ID. The estimated specificity was 99.93% for Ortho BioVue and 100% for DiaMed-ID and DG Gel. The score mean and range of the antibody titration of DG Gel, DiaMed-ID and Ortho BioVue were 34.31 (5-119), 30.3 (3-121) and 37.38 (3-112), respectively. All three column agglutination systems work well showing a high estimated diagnostic accuracy.

Agglutination Tests↗
PubMed2005

[Contrast sensitivity to intraocular lens TECNIS Z-9000].

PURPOSE: To evaluate the increase in contrast sensitivity to intraocular lens TECNIS Z-9000 (Pfizer) compared with other intraocular lenses. METHOD: We implanted a TECNIS Z-9000 lens in 18 patients who had another type of intraocular lens implanted in their other eye. We then tested contrast sensitivity under both mesopic and photopic conditions using the VCTS (Vision Contrast Test System) provided by Vistech Consultants Inc. RESULTS: There was an improved contrast sensitivity at low and medium frequencies, following TECNIS-Z 9000 lens implantation, however this improvement did not reach statistical significance. There were significant differences at high frequencies, which are directly related to the quality of visual function. CONCLUSIONS: TECNIS Z-9000 lens implantation (with a modified anterior surface) achieves a significant improvement in contrast sensitivity, meaning in practice an increase in the quality of visual function.

Contrast Sensitivity↗
PubMed2004

Specific interaction of tissue-type plasminogen activator (t-PA) with annexin II on the membrane of pancreatic cancer cells activates plasminogen and promotes invasion in vitro.

BACKGROUND: Overexpression of tissue plasminogen activator (t-PA) in pancreatic cancer cells promotes invasion and proliferation in vitro and tumour growth and angiogenesis in vivo. AIMS: To understand the mechanisms by which t-PA favours cancer progression, we analysed the surface membrane proteins responsible for binding specifically t-PA and studied the contribution of this interaction to the t-PA promoted invasion of pancreatic cancer cells. METHODS: The ability of t-PA to activate plasmin and a fluorogenic plasmin substrate was used to analyse the nature of the binding of active t-PA to cell surfaces. Specific binding was determined in two pancreatic cancer cell lines (SK-PC-1 and PANC-1), and complex formation analysed by co-immunoprecipitation experiments and co-immunolocalisation in tumours. The functional role of the interaction was studied in Matrigel invasion assays. RESULTS: t-PA bound to PANC-1 and SK-PC-1 cells in a specific and saturable manner while maintaining its activity. This binding was competitively inhibited by specific peptides interfering with the interaction of t-PA with annexin II. The t-PA/annexin II interaction on pancreatic cancer cells was also supported by co-immunoprecipitation assays using anti-t-PA antibodies and, reciprocally, with antiannexin II antibodies. In addition, confocal microscopy showed t-PA and annexin II colocalisation in tumour tissues. Finally, disruption of the t-PA/annexin II interaction by a specific hexapeptide significantly decreased the invasive capacity of SK-PC-1 cells in vitro. CONCLUSION: t-PA specifically binds to annexin II on the extracellular membrane of pancreatic cancer cells where it activates local plasmin production and tumour cell invasion. These findings may be clinically relevant for future therapeutic strategies based on specific drugs that counteract the activity of t-PA or its receptor annexin II, or their interaction at the surface level.

Annexin A2↗
PubMed2000

Flow cytometric assessment of allopurinol susceptibility in Leishmania infantum promastigote.

BACKGROUND: Leishmaniasis is a major tropical and subtropical parasitic disease. Sodium stibogluconate, N-methyl -D-glucamine antimoniate, amphotericin B, pentamidine, and ketoconazole are drugs used to treat this disease. Some of these drugs cause severe adverse side effects and treatment failures are common. Allopurinol, a purine analog, has been used to treat leishmaniasis, alone or combined with the previously mentioned drugs. Low cost, ease of administration (oral), and lack of toxicity make allopurinol a particularly appealing candidate. METHODS: The effect of allopurinol on Leishmania infantum (MCAN/ES/89/IPZ229/1/89, zymodeme MON1) wild-type promastigotes (wt-p229), and an altered form of these promastigotes (allo-p229) resulting from long term in vitro exposure to allopurinol, was determined by [(3)H]-thymidine incorporation assays and by diverse flow cytometric approaches. RESULTS: Allopurinol arrested the proliferative capacity of wt-p229 promastigotes, reduced the proportion of viable cells, and decreased their total protein content. In contrast, allo-p229 promastigote proliferation was only slightly decelerated and the proportion of viable cells and the protein content were not affected by the allopurinol treatment. CONCLUSIONS: The flow cytometry approach allowed us to demonstrate differences in allopurinol susceptibility of the two promastigote forms, expanding the spectrum of flow cytometry applications in studies of parasite resistance.

Allopurinol↗
PubMed2000

"It's a Wonderful Life". signaling generosity among the Ache of Paraguay.

Intensive food sharing among foragers and horticulturists is commonly explained as a means of reducing the risk of daily shortfalls, ensuring adequate daily consumption for all group members who actively pool resources. Consistently high food producers who give more than they receive, however, gain the least risk-reduction benefit from this daily pooling because they are the least likely to go without food on any given day. Why then do some high producers consistently share food, and why do some average producers share proportionally more food than others? We propose that although these individuals may not receive the same amounts they give (i.e., strict Tit-for-Tat), one explanation for their generosity is that they receive additional food during hard times. These include brief episodes of sickness, disease, injury, or accidents-fairly common events in traditional societies that can render individuals incapable of producing food, thereby having long-term effects on morbidity and fecundity and ultimately on lifetime reproductive success. Data collected among the Ache, a group of South American forager-horticulturists, indicate that those who shared and produced more than average (signaling cooperative intent and/or ability to produce) were rewarded with more food from more people when injured or sick than those who shared and produced below average. These results, framed within the context of tradeoffs between short-term and long-term fitness, may provide insight into motivations behind costly expenditures for establishing and reinforcing status and reputation.

Journal Article↗
PubMed2000

Detection of groundwater conduits in limestones with gravity surveys: data from the area of the Chicxulub Impact crater, Yucatan Peninsula, Mexico.

Small negative gravity anomalies are found in gravity data from along the northwestern shoreline of the Yucatan Peninsula. These anomalies are shown to be due to elongate, shallow anomalous porosity zones in the Tertiary carbonates. These zones are caused primarily by groundwater solution and are presently active conduits for groundwater flow. The association of these small gravity anomalies with known topographic and structural features of the area, which partially overlies the Chicxulub Impact crater, indicates their development was influenced by structures, faults and/or fractures, within the Tertiary and pre-Tertiary carbonates.

Calcium Carbonate↗
PubMed2000

Bioequivalence study of paracetamol tablets: in vitro-in vivo correlation.

The bioequivalence of three chemically equivalent paracetamol generic Mexican products (500 mg tablets) was evaluated in 12 healthy volunteers using the American innovator product (Tylenol, McNeil, Fort Washington, PA), as the reference. Single oral doses of each product were administered at 1-week intervals using a 4 x 4 Latin square design balanced for the first residual effect. The total amount of paracetamol excreted in urine in 24 hr was taken as a measure of bioavailability. In addition, moment analysis was used to estimate in vitro mean dissolution time (MDT) from dissolution profiles obtained following the USP 23 dissolution test specified for paracetamol tablets and to estimate in vivo mean residence time (MRT) from urinary excretion data. Significant differences in the dissolution performance and in the cumulative amount of paracetamol excreted in urine up to 24 hr were observed when the data were analyzed by analysis of variance (ANOVA) (p < .05). Classical and Westlake 90% confidence limits, as well as the two-sided t test proposed by Schuirmann, and the Anderson-Hauck power analysis supported the final conclusion that only one of the three generic paracetamol products studied can be considered equivalent to the reference product Tylenol. A linear correlation between in vitro MDT and in vivo MRT was found.

Acetaminophen↗
PubMed1999

Panorama of acute diarrhoeal diseases in Mexico.

We examined the recent panorama of ADD related deaths in Mexico in an effort to assess the overall impact of control measures that may vary in space and time. We pay particular attention to mortality rates recorded between 1985-1995, that is, before and after the cholera emergency. The aim is to focus on the social groups at risk, using time series data represented in the form of images and produced by a geographic information system (GIS). We show the potential of such methods to define populations at risk and support the decision process.

Acute Disease↗
PubMed1997

Minimum inhibitory concentrations for selected antimicrobial agents against Fusobacterium necrophorum isolated from hepatic abscesses in cattle and sheep.

Minimum inhibitory concentrations for 35 antimicrobial agents against 100 Fusobacterium necrophorum isolates from hepatic abscesses in sheep and cattle were determined. Twelve of the thirteen beta-lactam antibiotics tested inhibited growth of 100% of strains tested. Of the remaining antimicrobial agents, extensive susceptibility was found for: spiramycin, josamycin, lincomycin, tylosin, oxytetracycline, chlortetracycline, rufloxacin, metronidazole, cotrimoxazole, sulfadimethoxine, virginiamycin and fosfomycin.

Animals↗
PubMed1992

Clinical pharmacokinetics of albendazole in patients with brain cysticercosis.

Albendazole pharmacokinetics were studied in eight patients who were receiving albendazole in doses of 15 mg/kg per day for 8 days as treatment of brain cysticercosis. Albendazole was not detected in plasma, but its main metabolite albendazole sulphoxide could be measured. Maximum plasma levels for albendazole sulphoxide ranged from 0.45 to 2.96 micrograms/mL. The half-life of albendazole sulphoxide was between 10 and 15 hours. A double peak was found in three patients. Mean residence time values were from 14 to 20 hours. Plasma levels of albendazole sulphoxide at the steady state showed great intraindividual variability. The results suggest that albendazole can be administered twice daily rather than three times as is currently done.

Administration, Oral↗
PubMed1990

Dexamethasone increases plasma levels of albendazole.

Therapy of neurocysticercosis with cysticidal drugs is frequently complicated by the exacerbation of symptoms that follows the inflammation triggered by the acute destruction of cysticerci. Treatment of such adverse reactions with dexamethasone is highly effective. However, it has been shown that dexamethasone lowers the plasma levels of praziquantel, thus reducing its cysticidal efficacy. We measured plasma levels of albendazole, another strong cysticidal drug, when dexamethasone was given simultaneously. We found that dexamethasone increased the plasma levels of albendazole by about 50% (P less than 0.002); hence, it seems that cysticercosis and the ensuing inflammation can be treated simultaneously with albendazole and dexamethasone without diminishing the efficacy of the cysticidal drug.

Adult↗
PubMed1990

Plasma and CSF levels of albendazole and praziquantel in patients with neurocysticercosis.

Albendazole or praziquantel were measured in plasma and cerebrospinal fluid (CSF) in 29 patients with neurocysticercosis. Mean levels of albendazole in plasma were 0.918 microgram/ml and in CSF were 0.392 microgram/ml and levels of praziquantel were 1.640 micrograms/ml in plasma and 0.398 microgram/ml in CSF, after doses of 15 and 50 mg/kg, respectively. Drug concentrations in CSF were 43% for albendazole and 24% for praziquantel. The drug levels obtained for both drugs showed ample individual variations that were not related to age, sex, presence of inflammation in the subarachnoid space, or therapeutic effectiveness; such variations seem to be due to individual differences in pharmacokinetics. Both drugs were effective and the doses currently used of each drug seem to be optimal for therapy of neurocysticercosis.

Adolescent↗