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Biomedical subjects

A Guerrero

Publications and source records attributed to A Guerrero.

At least 73 records · Page 4Linked to original sources
PubMed2001

Spanish LLW and MLW disposal: durability of cemented materials in (Na, K)Cl simulated radioactive liquid waste.

The microstructural stability or durability of a specific backfilling pozzolanic-cement mortar, which is employed in Spain, in concrete containers for the storage of low level liquid wastes (LLW) and medium level liquid wastes (MLW), has been studied by means of the Koch-Steinegger test at the temperatures of 20 and 40 degrees C during a period of 365 days. Mortar samples were immersed in salt solutions of 3.46 M NaCl and 3.46 M KCl to simulate the salinity of some radioactive liquid waste matrices. The resistance of the mortar to the saline solution attack is evaluated by the development of the relative flexural strength. The changes of the microstructure were followed by mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Pore solution was extracted and analyzed at different periods of time to know the possible diffusion of sodium, chloride and potassium inside the microstructure.

Potassium↗
PubMed2001

Immunoferon, a glycoconjugate of natural origin, inhibits LPS-induced TNF-alpha production and inflammatory responses.

We have analyzed the effect of a patented glycoconjugate (GC) of natural origin, Inmunoferon, in the development of the response to endotoxemia induced by administration of LPS in rodents. We have observed that oral treatment with the drug reduced the levels of serum TNF-alpha induced by an intravenous pulse of LPS. The serum of pretreated mice blocked TNF-alpha production by peritoneal macrophages. The drug increased the levels of TNF-alpha regulators such as IL-10 and corticosteroids, whereas it inhibited TNF-alpha-dependent IL-6 production. Further TNF-alpha-dependent responses, such as cell extravasation, was decreased in treated mice. According to these results, Inmunoferon is postulated as an inhibitor of the systemic response to LPS. Correlation of the observations made in mice with a rat model suggests the efficacy of this product in reducing TNF-alpha production in a species-independent fashion and opens the possibility of its trial as an adjuvant of antibiotics in treatment against gram-negative bacterial infection.

Adjuvants, Immunologic↗
PubMed2001

Pheromone response inhibitors of the corn stalk borer Sesamia nonagrioides. Biological evaluation and toxicology.

The behavioral activity of some trifluoromethyl ketones (TFMKs) as inhibitors of the pheromone activity of the corn stalk borer Sesamia nonagrioides (Lef.) (Lepidoptera: Noctuidae) is reported. The most closely-related analogue to the pheromone tested, (Z)-11-hexadecenyl trifluoromethyl ketone (Z11-16:TFMK), elicited a significant decrease in the number of male catches in traps baited with mixtures with the pheromone in 1:1 and 10:1 ratios in comparison to the pheromone alone. The E isomer of the analogue as well as two highly hydrated ketones, 3-octylthio-1,1,1-trifluoropropan-2-one (OTFP) and 1,1-difluoropentadecyl trifluoromethyl ketone, were inactive. Conversely, the saturated TFMKs n-dodecyl trifluoromethyl ketone and, particularly, n-hexadecyl trifluoromethyl ketone induced a synergistic effect when mixed with the synthetic pheromone in 10:1 ratio. However, in a wind tunnel these chemicals did not elicit any differential effect on flying moths attracted to a source containing a 10:1 blend of the analogue and the pheromone. In a dual choice bioassay with two dispensers, containing the pheromone alone, and mixtures of Z11-16:TFMK and the pheromone and separated 5 cm apart, males showed no particular preference for either dispenser. The ketone mixture, however, induced moths to execute erratic flights with frequent crosswind counter-turns and intersections with plume boundaries. The total number of contacts with the source were reduced when a control dispenser was paired with a dispenser containing Z11-16:TFMK and pheromone. Z11-16:TFMK and OTFP showed little toxicity on mice with a LD50 of 1 g/kg after the 6th day of treatment. For comparitive purposes, the major component of the pheromone, Z11-16:Ac, displayed a LD50 of 5 g/kg 6 days after application. Our results provide additional information about the activity of the TFMKs, which might be useful for the utilization of these chemicals in future pest control studies.

Animals↗
PubMed2001

Antiplatelet effects of prostacyclin and nitric oxide in patients with type I diabetes and ischemic or edematous retinopathy.

The aim of this study was investigate prostacyclin and nitric oxide (NO) and their platelet second messengers cAMP and cGMP, in patients with type I diabetes with or without retinopathy. We compared 20 healthy volunteers and 97 patients with type I diabetes: 24 with no signs of diabetic retinopathy (DR), 43 with ischemicproliferative DR, and 30 with edematous DR. The following parameters were recorded: platelet aggregometry, nitrites/nitrates, 6-keto-prostaglandin-F(1alpha), and intraplatelet cAMP and cGMP. Platelet aggregation was greater in patients with edematous DR. The platelets in patients with diabetes were more resistant to inhibition by prostaglandin E(1) or sodium nitropruside. Nitrite concentration in patients with ischemic-proliferative DR was 80% lower than the value in healthy controls, but there was no significant difference between the control group and patients with edematous DR. In the latter group, stimulation of neutrophils with L-arginine increased nitrite + nitrate production by 44 +/- 3.6%, whereas in patients with ischemic-proliferative DR, the increase was 9.8 +/- 0.8%. We conclude that NO production is higher in patients with type I diabetes and edematous retinopathy than in those with ischemic-proliferative retinopathy. This finding, together with the possibly greater production of free radicals, may explain the greater impairment of platelet function in the former patients.

Adult↗
PubMed2001

Fibroblasts from the transversalis fascia of young patients with direct inguinal hernias show constitutive MMP-2 overexpression.

OBJECTIVE: To determine the expression pattern of certain metalloproteinases (MMPs) known to be involved in the degradation of the extracellular matrix in cultured fibroblasts from the transversalis fascia (TF) of patients with inguinal hernia. SUMMARY BACKGROUND DATA: Inguinal hernia is a common pathology, the cause of which remains unknown. It is, however, clear that the TF is one of the anatomical structures that may impede the formation of hernias, and particularly the direct type of hernia. In previous studies the authors found enhanced MMP-2 expression in TF specimens in vivo. The persistence of increased expression in cultured fibroblasts might support the idea of a genetic defect as the cause for this pathology. METHODS: Fibroblasts from the TF of patients with direct and indirect inguinal hernia were cultured and compared with those obtained from control TF in terms of MMP (MMP-2 and MMP-9) expression. RESULTS: Significant active MMP-2 expression was shown by TF fibroblasts from young patients with direct hernias. These findings were confirmed by immunosorbent assay, immunoblotting, and zymography of the fibroblast culture media. No MMP-9 expression was detected. CONCLUSION: These results indicate that MMP-2 may be involved in the TF matrix degradative process in patients with direct hernia. The persistence of changes in MMP-2 levels in the cell cultures appears to suggest a genetic defect or irreversible change as the origin of this pathology rather than environmental factors, which may later participate in the development of the hernial process.

Adult↗
PubMed2001

Antiangiogenic effect of betamethasone on the chick cam stimulated by TA3 tumor supernatant.

Tumor growth is the result of combined cell proliferation overwhelming cell death and neoangiogenesis. This report shows CAM angiogenesis promoted by TA3 tumor supernatant with or without low dosis of betamethasone (Minimal antiangiogenic concentration: beta-MAAC). Methylcellulose discs instilled with 10 microliters of beta-MAAC (0.08 microgram/ml), 10 microliters of tumor supernatant (TA3ts), 5 microliters beta-MAAC + 5 microliters TA3ts, and 10 microliters of PBS as control were implanted in host chick eggs. On day 12, the grafts were removed, photographed and fixed. Sections were stained in parallel, one and three with hematoxylin-eosin, and section two by the Tunel method. The number of vessels was evaluated in a microscopic field of the CAM (2250 micron 2). The results show that beta-MAAC produced a significant inhibition of neovascularization in comparison to that observed in controls (P < 0.0025; Student t-Test). Discs instilled with TA3ts produced an intense stimulation of angiogenesis in contrast, when discs were instilled with 5 microliters of beta-MAAC + 5 microliters of TA3ts the angiogenesis was significantly inhibited (P < 0.001). The results show that effective antiangiogenic doses of betamethasone are in the range of 10(-7) M, (probably a genomic mediated action) and that this effect of low concentration may have clinical applications.

Allantois↗
PubMed2001

Risk factors for nosocomial transmission of multidrug-resistant tuberculosis due to Mycobacterium bovis among HIV-infected patients.

OBJECTIVE: To identify risk factors for transmission of multidrug-resistant tuberculosis (MDR-TB) among hospitalized human immunodeficiency virus (HIV) infected patients exposed during a nosocomial outbreak. DESIGN: Case control study. Cases were HIV-infected patients with MDR-TB due to Mycobacterium bovis (MDR-TBMb) who acquired the disease after exposure to an MDR-TBMb patient in an hospital ward. Controls were HIV-infected patients exposed to a case of MDR-TBMb in an hospital ward but who did not develop MDR-TBMb during the follow-up. RESULTS: Nineteen cases and 31 controls were included. CD4 cell counts were significantly lower among cases. Exposure in the infectious diseases ward or exposure to the index patient were associated with development of MDR-TBMb, while exposure during a single-room hospital stay and exposure in the respiratory isolation ward were associated with non-development of MDR-TBMb. A multiple regression logistic model showed that only a CD4 cell count below 50/microL and exposure to the index patient increased the risk of developing MDR-TBMb (P < 0.05). Hospitalization in a single room seemed to protect HIV-infected patients from developing nosocomial MDR-TBMb (P = 0.052). CONCLUSIONS: Over classic risk factors, such as length of exposure or sharing a room with a case, severe immunosuppression independently increases the risk of MDR-TB transmission in the context of a nosocomial MDR-TB outbreak among HIV-infected patients. This information must be considered in the management of tuberculosis outbreaks. Patients with CD4 cell counts below 50/microL should be the principal group targeted for prevention strategies in nosocomial outbreaks.

Adult↗
PubMed2001

[Cytomegalovirus sensitivity to anti-retroviral agents in patients infected with the human immunodeficiency virus with chorioretinitis in Spain].

OBJECTIVES: To determine the prevalence of the in vitro resistance rate of cytomegalovirus (CMV) to gancyclovir (GCV) and foscarnet (FOS) among patients with AIDS and chorioretinitis. Furthermore, in vitro sensitivity results were compared with the clinical response to therapy. PATIENTS AND METHODS: Thirty-six patients with the diagnosis of CMV retinitis and AIDS were included in the study. Antiviral sensitivity testing was performed to 51 clinical CMV strains from these patients. The in vitro sensitivity was compared with the clinical response to therapy. The resistance criteria were the inhibitory dose50 (ID50) GCV > 5 M and ID50 FOS > 400 M. RESULTS: None of the CMV tested strains was resistant to GCV or FOS; however, six patients who had relapses of chorioretinitis while on maintenance therapy and isolation during the condition had mean ID50 of strains (n=8) of 1,95 M for GCV (standard deviation [SD] of 0.71) and 115.2 for FOS (SD, 34.7). These patients responded well when drugs were used at induction doses. CONCLUSION: The in vitro sensitivity testing is not a good predictor of infection control when the drug is used at maintenance doses. This suggests that these strains should be classified in the intermediate resistant category.

AIDS-Related Opportunistic Infections↗
PubMed2001

[Clinical experience with icodextrin. Multicenter study].

UNLABELLED: The aim of this study was to analyse our experience with icodextrin in Andalusia, Spain. The study includes 51 patients (30 women and 21 men) on peritoneal dialysis (21 on CAPD and 30 on Automated Peritoneal Dialysis) treated with icodextrin for 10.3 +/- 7 months (0-41 months). Their mean age was 57 +/- 18 years (18-86 years). We have recorded the appearance of side effects, and the evolution of several biochemical parameters at baseline and after 6, 12 ans 18 months from initiation of icodextrin. We also studied drainage fluid from 12 patients after an icodextrin exchange. RESULTS: There were side effects (all cutaneous) in 4 out of 51 patients (7.8%). Two of the affected suffered from cutaneous hypersensitivity reactions, and icodextrin had to be suspended; the other two had exfoliative dermatitis affecting hands and feet that disappeared without have to withdraws icodextrin. Biochemical parameters: Serum sodium levels decreased from baseline to six months (138 +/- 6 mEq/l vs 136 +/- 3 mEq/l; p = 0.006), and then persisted at the same levels throughout the rest of the study period. There was a slight but significant decreased of serum HDL-cholesterol at six months vs baseline (55 +/- 26 mg/dl vs 51 +/- 20 mg/dl, p = 0.04), and a further decrease at twelve months vs six months (42 +/- 15 mg/dl vs 51 +/- 13 mg/dl, p = 0.054). There were no significant variations of glucose, osmolality, cholesterol, LDL-cholesterol (tendency to increase), triglycerides, beta 2 m and weight (tendency to increase; p = 0.08). In relation with the icodextrin exchange: average ultrafiltration 296 +/- 119 ml (ranging from 104 to 480 ml), creatinine clearance 1.9 +/- 0.5 litres (20.5% of daily creatinine clearance), urea clearance 2.08 +/- 0.5 litres (18.7% of daily urea clearance), total protein losses 3.2 +/- 0.9 g, albumin losses 1.4 +/- 0.5 g; urea and creatinine clearances were negatively correlated with ratios D/P4 of urea and creatinine of PET and positively correlated with ratio G4/G0. In conclusion, side effects are scarce with the use of icodextrin. As described in other studies, there is a trend to a slight decrease in serum sodium. The long-term use of icodextrin does not-prevent weight gain or deterioration of patients on peritoneal dialysis, despite the diminution of glucose load.

Adolescent↗
PubMed2000

Direct evidence of a radical mechanism in the addition reaction of iododifluoroesters to olefins by spin trapping

We present EPR analysis of the reaction of ethyl iododifluoroacetate with 1-tetradecene in the presence of Zn + NiCl2 x 6H2O, confirming the mechanistic studies that provide evidence of a single electron transfer process. We have trapped for the first time the ethoxycarbonyldifluoromethyl radical with a variety of spin traps, such as phenyl tert-butyl nitrone (PBN), 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), 2-methyl-2-nitrosopropane (MNP), and 2-nitro-2-nitrosopropane (NNP), and the EPR spectra of the corresponding adducts have been recorded. In a second step the ethoxycarbonyldifluoromethyl radical adds to the olefin to furnish a second radical intermediate, which can be trapped with NNP. Evidence of this second radical was obtained by EPR only with electron-rich olefins, such as alpha-methylstyrene and 2,4,6-trimethylstyrene, and the new adducts were recorded and interpreted. In addition, we also report the EPR spectra of the corresponding adducts when other alkylating reagents are used, such as ethyl iodoacetate, n-perfluorohexyl iodide, methyl omega-iodohexadecanoate, and n-butyl iodide.

Journal Article↗
PubMed2000

Role of antiretroviral therapy in long-term survival of patients with AIDS-related pulmonary aspergillosis.

The aim of the study presented here was to describe the clinical presentation and outcome of invasive pulmonary aspergillosis (IPA) in a cohort of HIV-infected patients and to assess factors associated with survival by means of a longitudinal study of all HIV-infected adults with IPA who attended the infectious diseases service of a tertiary center between January 1985 and December 1998. The outcome measure was the time to death after diagnosis of IPA. The endpoint for data collection and survival analysis was 31 December 1998. Nineteen of 1,605 HIV-infected patients were identified, resulting in an overall IPA attack rate of 1.12%. Most patients had AIDS (95%). Unilateral cavitary disease was the most frequent radiographic presentation (37%). Median survival was 148 days (95% confidence interval [95% CI], 0-402), but it exceeded 12 months in 37%. In patients in whom antiretroviral treatment (ART) was initiated or modified in relation to the IPA diagnosis, median survival increased to 906 days (95% CI, 754-1,058; 1-year survival, 83%) compared with 86 days in those who did not take any ART (95% CI, 55-117; 1-year survival, 8%; P=0.0002). Survival was even longer when ART changes included only nucleoside reverse transcriptase inhibitors, prior to the availability of protease inhibitors (833 days, 95% CI, 369-1,297; 1-year survival 75%; P=0.003). Three (16%) patients are still alive after a mean time of 36 months postdiagnosis. Although IPA is a life-threatening complication of advanced AIDS, it does not always lead to short-term death. An adequate management of HIV infection together with antifungal treatment may prolong survival and, as described for other AIDS-related disorders, a significant decrease in its occurrence can be expected.

AIDS-Related Opportunistic Infections↗
PubMed2000

Behavioral responses of the diamondback moth, Plutella xylostella, to green leaf volatiles of Brassica oleracea subsp. capitata.

Green leaf volatiles (GLVs) from Brassica oleracea subsp. capitata L. have been identified as 1-hexanol, (Z)-3-hexen-1-ol, 1-hexen-3-ol, hexanal, (E)-2-hexenal, hexyl acetate, and (Z)-3-hexenyl acetate, by their mass spectra and retention times in comparison with authentic samples. No isothiocyanates were found in the extract. The activity of these chemicals has been determined on mated and unmated males and females of the diamondback moth (DBM) Plutella xylostella in the laboratory (wind tunnel) and in the field. On unmated males, mixtures of (Z)-3-hexenyl acetate, (E)-2-hexenal, and (Z)-3-hexen-1-ol with the pheromone induced attractant/arresting behavior in 80-100% of the males tested, significantly higher than the effect induced by the pheromone alone. On mated males and unmated females the effect of the GLVs alone or in combination with the pheromone was poor, while on mated females these compounds elicited upwind flight and arresting behavior in 40-60% of the females assayed. There was no synergism when these chemicals were mixed with the pheromone. In the field, (Z)-3-hexenyl acetate, the most active GLV in laboratory tests, when mixed with the pheromone in 1:1 ratio, enhanced 6-7-fold the number of females and 20-30% the number of males caught by traps over those baited with the pheromone alone. Our results indicate that the enhancement of the attraction of both males and females of the DBM to traps baited with pheromone blended with the relatively inexpensive and environmentally safe (Z)-3-hexenyl acetate may be important for future control strategies of the pest.

Animals↗
PubMed2000

Diagnostic value of polymerase chain reaction in blood and aqueous humor in immunocompetent patients with ocular toxoplasmosis.

PURPOSE: To evaluate the diagnostic value of polymerase chain reaction (PCR) in blood and aqueous humor samples from immunocompetent patients with reactivated ocular toxoplasmosis. METHODS: Group 1 was composed of seven patients with a clinical diagnosis of reactivated ocular toxoplasmosis. Group 2 consisted of 33 controls. In each subject, blood and aqueous humor samples were obtained for detection of Toxoplasma gondii DNA by means of simple PCR, seminested PCR, and Southern blot hybridization. RESULTS: Group 1: Simple PCR was positive in 3 of 7 blood samples (42%) and in 2 of 7 (28%) aqueous humor samples. Seminested PCR was positive in 4 of 7 (57%) blood samples and in 3 of 7 (42%) aqueous humor samples. Group 2: Simple and seminested PCR were positive in both samples in 2 of 33 (6%) and 4 of 33 (12%), respectively. Sensitivity 57% (18.41-90.10), specificity 87% (71.80-96.60); positive and negative likelihood ratio 4.38 and 0.49, respectively. CONCLUSIONS: Polymerase chain reaction can be useful for confirming the diagnosis of ocular toxoplasmosis, especially in those eyes where fundus examination does not yield conclusive results. The detection of T. gondii DNA in blood suggests that reactivation of ocular toxoplasmosis cannot be considered a local event.

Adult↗
PubMed2000

Diagnostic utility of a multiplex herpesvirus PCR assay performed with cerebrospinal fluid from human immunodeficiency virus-infected patients with neurological disorders.

We used a multiplex nested-PCR assay for the simultaneous detection in cerebrospinal fluid (CSF) of five human herpesviruses (HVs) (cytomegalovirus [CMV], Epstein-Barr virus [EBV], varicella-zoster virus [VZV], herpes simplex virus [HSV], and human herpesvirus 6 [HHV-6]) in a clinical evaluation of human immunodeficiency virus (HIV)-infected patients with neurological disorders. This method, which has the advantages of being rapid and economical, would be of particular interest for the diagnosis of neurological syndromes caused by more than one HV. We studied 251 CSF samples from 219 patients. HV DNA was demonstrated in 93 (37%) of the CSF samples (34% of the patients). CMV was the HV most frequently detected in our patients (25%), while EBV, VZV, HSV, and HHV-6 DNAs were present in significantly fewer cases (7, 4, 3, and 1%, respectively). When results were compared with the final etiological diagnoses of the patients, the multiplex HV PCR showed high specificity for the diagnosis of CMV and VZV neurological diseases and for cerebral lymphoma (0.95, 0.97, and 0.99, respectively). The sensitivity of the assay was high for CMV disease (0.87), was low for cerebral lymphoma (0.33), and was not evaluable for VZV disease due to the small number of patients with this diagnosis. Nevertheless, detection of VZV DNA had possible diagnostic value in four of the nine cases, and EBV DNA amplification always predicted the diagnosis of cerebral lymphoma in patients with cerebral masses. Detection of HSV DNA was frequently associated with CMV amplification and fatal encephalitis. HHV-6 was not considered to have a pathogenetic role in the three cases in which it was detected. This multiplex HV PCR assay is a specific and clinically useful method for the evaluation of HIV-infected patients with neurological disorders related to HV.

AIDS-Related Opportunistic Infections↗
PubMed2000

Insect parapheromones in olfaction research and semiochemical-based pest control strategies.

The possibility of disrupting the chemical communication of insect pests has initiated the development of new semiochemicals, parapheromones, which are anthropogenic compounds structurally related to natural pheromone components. Modification at the chain and/or at the polar group, isosteric replacements, halogenation or introduction of labeled atoms have been the most common modifications of the pheromone structure. Parapheromones have shown a large variety of effects, and accordingly have been called agonists, pheromone mimics, synergists and hyperagonists, or else pheromone antagonists, antipheromones and inhibitors. Pheromone analogues have been used in quantitative structure-activity relationship studies of insect olfaction, and from a practical point of view they can replace pheromones when these are costly to prepare or unstable under field conditions.

Animals↗