Biomedical subjects

B Jimenez

Publications and source records attributed to B Jimenez.

At least 19 recordsLinked to original sources

PubMed2006

Pigment epithelium-derived factor as a multifunctional antitumor factor.

The design of new therapeutic strategies for cancer treatment is based on the combination of drugs directed against different tumor compartments, including the tumor cells themselves and components of the stroma, such as the tumor vasculature. Indeed, several antiangiogenic compounds have entered clinical trials for use alone or in combination with conventional cytotoxic drugs. Pigment epithelium-derived factor (PEDF) is a multifunctional natural peptide with complex neurotrophic, neuroprotective, antiangiogenic, and proapoptotic biological activities, any of which could potentially be exploited for therapeutic purposes. This review summarizes recent studies that reveal the antitumor potential of PEDF based on its antiangiogenic properties and its newly discovered direct antitumor effects, which involve the induction of differentiation or apoptosis in tumor cells. We also discuss possible therapeutic applications of PEDF, based on these mechanistic insights and on the identification of functional domains that retain specific biological activities.

Angiogenesis Inhibitors↗

PubMed2006

Particle size distribution to design and operate an APT process for agricultural wastewater reuse.

Total suspended solids is a parameter commonly used to operate and design coagulation-flocculation processes. Nevertheless, their application for an advanced primary treatment (a high performance but low dose demand coagulation processes coupled with a high rate sedimentator, sometimes called enhanced primary treatment) is not the best option to produce an effluent for agricultural irrigation. This paper compares the best operating conditions obtained using the TSS or the PSD (particle size distribution) as parameters to follow the efficiency. The treatment objective was to remove particles >20 microm, in such conditions that the effluent can contain organic matter and nutrients necessary for crops with a reduced number of helminth ova (with sizes between 20 to 80 microm). Using the TSS as parameter, the best coagulation (460 s(-1), 60 s contact time and 300 micromolAl/L) and flocculation (20 s(-1) with 15 min) conditions produced an effluent with 1.2 HO/L. To obtain a similar results but using operating conditions determined with the PSD at a three times lower coagulant dose can be employed (diminishing operating costs and reducing the quantity of sludge produced), and a reduction on energy consumption of around eight times can be reached. Best operating conditions defined using the PSD (160 s(-1), 60 s contact time and 100 micromolAl/L) produced an effluent with <0.4 HO/L.

Agriculture↗

PubMed2006

Using Ecosan sludge for crop production.

This paper presents the microbial risks associated with the reuse of Ecosan sludge in agriculture. Sludge from KwaZulu Natal Province in South Africa with a helminth ova content of 30 HO/g TS, faecal coliforms of 10(6) CFU/g TS, faecal streptococci of 10(6) CFU/g TS and Salmonella spp. of 10(5) CFU/g TS was used for this purpose. Applying different rates of sludge to spinach and carrots resulted in an increase in bacterial and helminth ova counts in crops as the quantity of sludge increased. The helminth ova content in crops was always greater in leaves than in stems, with a content varying from 2 to 15 HO/g TS for spinach with sludge application rates of 0-37.5 ton/ha and from 2-8 HO/g TS for carrot crops with sludge application rates varying from 0-35 ton/ha. Nevertheless, viability in crops was 20-25%, reducing the risk of disease. Consequently, the development of an Ecosan sludge revalorisation standard is considered important. Some recommendations are made taking into account the characteristics of the sludge as well as conditions in rural areas.

Animals↗

PubMed2006

Comparison of techniques for the detection of helminth ova in drinking water and wastewater.

Many countries use wastewater for irrigation. The World Health Organization established, as reuse guidelines, a maximum value of 1 helminth ovum/L for irrigation. Various techniques for enumerating helminth ova in water have been published. To determine the most adequate method for Mexico, four techniques were compared: the U.S. Environmental Protection Agency (U.S. EPA), membrane-filter, Leeds I, and Faust. Two types of water were used: drinking water and municipal wastewater effluent. Sensitivity, discrimination coefficients, precision, recovery efficiency, and cost were determined. In addition, several unseeded wastewater samples were analyzed. For drinking water, U.S. EPA and the membrane-filter techniques demonstrated comparable results; however, when wastewater was used, the membrane technique showed some deficiencies. Because the U.S. EPA technique may be used for samples with both high and low solids content, allows for the recovery of helminth ova with different specific gravities, and has the lowest total cost, it was selected as the best technique.

Agriculture↗

PubMed2004

Polybrominated diphenylethers and methoxylated tetrabromodiphenylethers in cetaceans from the Mediterranean Sea.

Eight tetrabrominated to hexabrominated diphenylethers were present at ppb levels in liver from cetaceans found stranded on the beaches of the Mediterranean Sea, Italy. The highest concentration was found in striped dolphin (sum polybrominated diphenyl ethers [PBDE] 8133 ng/g l.w.) and the lowest concentration in bottlenose dolphin (sum PBDE 66 ng/g lipid weight [l.w.]). The predominant congener in all samples was 2,2',4,4'-tetraBDE (PBDE # 47) followed by, in decreasing order, the pentaPBDE # 99 and 100 and the hexaPBDE # 154 and 153. In 12 of the 14 analyzed samples, 3 different methoxylated PBDEs (MeO-PBDE # 1, 2, and 3) were detected at semiquantitatively calculated concentration ranges of 2 to 14 ng/g l.w.; 5 to 167 ng/g l.w.; and 7 to 628 ng/g l.w., respectively. In addition, several unidentified bromine compounds were seen when screening the samples in negative-chemical ionization (NCI) mode monitoring m/z 79 and 81, which illustrates the importance of running both electron-impact ionization and NCI when analyzing environmental samples. Electron-impact ionization is more specific for monitoring the molecular ion compared with NCI, which might overestimate the concentration of certain PBDE congeners.

Animals↗

PubMed2004

Sustainable sludge management in developing countries.

Worldwide, unsanitary conditions are responsible for more than three million deaths annually. One of the reasons is the low level of sanitation in developing countries. Particularly, sludge from these regions has a high parasite concentration and low heavy metal content even though the available information is limited. Different issues needed to achieve a sustainable sludge management in developing nations are analysed. Based on this analysis some conclusions arise: sludge management plays an important role in sanitation programs by helping reduce health problems and associated risks; investments in sanitation should consider sludge management within the overall projects; the main restriction for reusing sludge is the high microbial concentration, which requires a science-based decision on the treatment process, while heavy metals are generally low; adequate sludge management needs the commitment of those sectors involved in the development and enforcement of the regulations as well as those that are directly related to its generation, treatment, reuse or disposal; current regulations have followed different approaches, based mainly on local conditions, but they favour sludge reuse to fight problems like soil degradation, reduced crop production, and the increased use of inorganic fertilizers. This paper summarises an overview of these issues.

Biodegradation, Environmental↗

PubMed2004

Particle size distribution as a useful tool for microbial detection.

Worldwide, raw or treated wastewater is used for irrigation. However, this practice implies that the microbial content must be controlled. Unfortunately, detection techniques for microorganisms are costly, time consuming, and require highly trained personnel. For these reasons, this study used particle size distribution to measure the microbial quality of wastewater through correlations between the number or volume of particles and the concentration of fecal coliforms, Salmonella spp. and helminth ova. Such correlations were obtained for both raw and chemically treated wastewater. The best fit was the one for helminth ova, which applies for both the influent and effluent and also for all the coagulants involved. This technique allows the on-line quantification of helminth ova at a cost of US$3 and it takes only 5 minutes, instead of the US$70 and 5 days for the standard technique. With respect to the coagulants applied, their behavior is different only for particles smaller than 8 microm, and thus this value is considered as the critical size for this particular treatment. The best coagulant was the aluminium polychloride. In addition, this work establishes the distribution of COD, TSS, nitrogen, and phosphorous for particles smaller and larger than 20 microm.

Agriculture↗

PubMed2004

Quality assessment of an aquifer recharged with wastewater for its potential use as drinking source: "El Mezquital Valley" case.

Mexico City, with a population of 18 million, has been sending its wastewater for more than 100 years to the Tula Valley where it is used to irrigate 90,000 ha. Due to the large wastewater volume (60 m3/s) sent through unlined channels, combined with the use of very high irrigation rates, artificial recharge of the local aquifer has been occurring. This recharge is estimated in more than 25 m3/s. As a consequence, the water table has raised and several springs have appeared in the last decades with flows between 100 to 600 L/s. These springs and several wells are the water sources in the region. An evaluation of the Tula Valley aquifer quality was performed to analyze the use of such water as source of drinking water for Mexico City. The work is divided into 5 individual projects: (a) drinking water quality in the Tula Valley; (b) water availability in the Tula Valley; (c) wastewater treatment due to its use for irrigation, (d) use of membrane processes to treat groundwater; and (d) biota developed in the new surface water reservoirs. Results show that it is feasible to use this reclaimed water as drinking source.

Cities↗

PubMed2004

Disinfection kinetics of pathogens in physicochemical sludge treated with ammonia.

Ammonia is a disinfectant which can diffuse through the membrane of highly resistant structures like helminth ova. Thus, it can be considered an alternative disinfectant of wastewater sludge with high pathogenic content. In this study, the kinetic parameters of the Hom model were used to describe the inactivation with ammonia of faecal coliforms, Salmonella spp. and viable helminth ova. These were obtained in processes considering the addition of ammonia alone as well as for ammonia combined with an increase in temperature. The sludge was sampled from a municipal wastewater treatment plant using an APT (Advanced Primary Treatment) or CEP (Chemical Enhanced Primary) process. With 20% w/w of ammonia, 7 logs of faecal coliforms, 6 logs of Salmonella spp., and 83% of viable helminth ova were reduced in 2 hours contact time. To eliminate 100% of the helminth ova from samples having 88-132 ova/g TS it was needed to combine 20% of ammonia with 50 degrees C. The analysis of parameters k, n and m indicate higher resistance to inactivation of helminth ova compared to bacteria and a better performance of the ammonia process than lime stabilization to inactivate microorganisms. In addition, ammonia increased the agricultural value of the biosolids produced.

Ammonia↗

PubMed1999

Keratinocyte growth factor induces angiogenesis and protects endothelial barrier function.

Keratinocyte growth factor (KGF), also called fibroblast growth factor-7, is widely known as a paracrine growth and differentiation factor that is produced by mesenchymal cells and has been thought to act specifically on epithelial cells. Here it is shown to affect a new cell type, the microvascular endothelial cell. At subnanomolar concentrations KGF induced in vivo neovascularization in the rat cornea. In vitro it was not effective against endothelial cells cultured from large vessels, but did act directly on those cultured from small vessels, inducing chemotaxis with an ED50 of 0.02-0.05 ng/ml, stimulating proliferation and activating mitogen activated protein kinase (MAPK). KGF also helped to maintain the barrier function of monolayers of capillary but not aortic endothelial cells, protecting against hydrogen peroxide and vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) induced increases in permeability with an ED50 of 0.2-0.5 ng/ml. These newfound abilities of KGF to induce angiogenesis and to stabilize endothelial barriers suggest that it functions in microvascular tissue as it does in epithelial tissues to protect them against mild insults and to speed their repair after major damage.

Animals↗

PubMed1998

Multiple forms of angiostatin induce apoptosis in endothelial cells.

Angiostatin is a circulating inhibitor of angiogenesis generated by proteolytic cleavage of plasminogen. In this study we have used recombinant human and murine angiostatins (kringles 1-4) as well as native human angiostatin (prepared by elastase digestion of plasminogen [kringles 1-3] or by plasmin autocatalysis in the presence of a free sulfhydryl donor [kringles 1-4]). We report that angiostatin reduces endothelial cell number in a 4-day proliferation assay without affecting cell cycle progression into S-phase (as determined by bromodeoxyuridine labeling). This suggested that the reduction in cell number in the proliferation assay might in part be due to cytotoxicity. This was confirmed by the observation that ethidium homodimer incorporation (a measure of plasma membrane integrity) into endothelial cells was increased by angiostatin in a manner similar to that seen with tumor necrosis factor- (TNF-) and transforming growth factor-beta1 (TGF-beta1), both of which induce apoptosis in endothelial cells. In contrast to TNF- and TGF-beta1, angiostatin did not induce cytotoxicity in human MRC-5 fibroblast, rat smooth muscle, canine MDCK epithelial, or murine B16-F10 melanoma cell lines. Angiostatin-induced apoptosis was confirmed by endothelial cell nuclear acridine orange incorporation as well as by annexin V and TUNEL staining. These in vitro findings point to endothelial cell apoptosis as a mechanism for the antiangiogenic effect of angiostatin in vivo.

Angiostatins↗

PubMed1997

Fingerprint of polycyclic aromatic hydrocarbons in two populations of southern sea lions (Otaria flavescens).

The fingerprint of 14 polycyclic aromatic hydrocarbons (PAHs) was investigated in biopsy, fur, blood, liver and faeces of live and dead specimens of two Argentinian population of southern sea lion (Otaria flavescens). One colony lives in Mar del Plata harbour which is particularly polluted with petroleum, the second (control) colony lives at Punta Bermeja (Patagonia). The highest concentrations of the five carcinogenic PAHs were found in the Mar del Plata sea lions.

Animals↗

PubMed1997

Skin biopsy as a nondestructive tool for the toxicological assessment of endangered populations of pinnipeds: preliminary results on mixed function oxidase in Otaria flavescens.

The aim of this study was to develop and validate a method for assessing the toxicological risk of endangered populations of pinnipeds based on a nondestructive biological tool, the skin biopsy specimen. Skin biopsies can be obtained from pinnipeds by anaesthetising the animals and taking a small amount of skin in the anterior flipper area, or by shooting a biopsy dart with a crossbow. Skin biopsy material is suitable for a wide range of chemical and biomarker analysis. Organochlorines and polycyclic aromatic hydrocarbons can be analysed in subcutaneous fat and MFO activity (BPMO), Cyt.P450 isoforms, and DNA damage can be detected in epidermis.

Animals↗

PubMed1996

The first intron of the Arabidopsis thaliana gene coding for elongation factor 1 beta contains an enhancer-like element.

Genomic and cDNA clones coding for elongation factor-1 beta (eEF-1 beta) from Arabidopsis thaliana (At) were isolated and characterized. eEF-1 beta was found to be encoded by a single-copy At gene. Chimeric genes fusing the promoter and the 5' untranslated region of the At eEF-1 beta gene to the gus reporter gene were constructed and used to study the expression of this gene in transgenic tobacco plants. Interestingly, it was found that the first intron of this gene is required for high levels of expression. Experiments using chimeric promoters showed that an enhancer-like element is present in the first intron of At eEF-1 beta. Gel-shift assays were used to demonstrate that this intron is specifically bound by putative transcription factors present in nuclear protein extracts.

Amino Acid Sequence↗

PubMed1996

Levels of PCDDs, PCDFs and non-ortho PCBs in dietary supplement fish oil obtained in Spain.

Levels of PCDDs, PCDFs and non-ortho PCBs are reported for fish oils available in Spain which are consumed by the population as a dietary supplement. Trace enrichment methodology based on the use of modified silica and activated carbon chromatography was combined with on-column extraction (FMS 100) to separate PCDDs, PCDFs and PCBs from lipid material. The extracts were further cleaned up on disposable Florisil columns and analysed by HRGC/HRMS (PCDD/F and non-ortho PCB fractions). Mean levels found in the samples were 10.50 ppt for total PCDDs and 9.95 ppt for total PCDFs. Calculated PCDD/F I-TEQ values were found to be 2.11 ppt on a lipid weight basis. Total mean levels found for co-planar PCBs (#77, 126 and 169) were 18.26 ppt and the calculated I-TEQ value was 0.31 ppt on a lipid weight basis.

Benzofurans↗

PubMed1996

Pleural fluid to serum cholinesterase ratio for the separation of transudates and exudates.

STUDY OBJECTIVE: To evaluate the usefulness of two new parameters for separating pleural transudates and exudates: pleural fluid cholinesterase level and pleural fluid to serum cholinesterase ratio, and to compare the results with the other well-established criteria. DESIGN: Prospective evaluation of the patients referred for diagnostic thoracentesis. SETTING: Pulmonary sections of a community hospital and a university hospital. PATIENTS: One hundred ninety-three consecutive patients. Forty were excluded for different reasons. MEASUREMENTS: The following criteria for separating the pleural effusions in transudates and exudates were analyzed: Light's criteria, the pleural fluid cholesterol level, the pleural fluid to serum cholesterol ratio, the pleural fluid cholinesterase level, and the pleural fluid to serum cholinesterase ratio. RESULTS: One hundred fifty-three patients had conditions diagnosed. Thirty-five were classified as having transudates and 118 as exudates. The percentage of effusions misclassified by each parameter was as follows: Light's criteria, 7.8%; pleural fluid cholesterol, 7.8%; pleural fluid to serum cholesterol ratio, 6.5%; pleural fluid cholinesterase, 8.5%; and pleural fluid to serum cholinesterase ratio, 1.3%. CONCLUSIONS: The pleural fluid to serum cholinesterase ratio is the most accurate criterion for separating pleural transudates and exudates. If further studies confirm our results, the cholinesterase ratio could be used as the first step in the diagnosis of pleural effusions.

Cholesterol↗

PubMed1994

Cadmium-induced sexual dysfunction does not involve increased hepatic metabolism of testosterone nor increased circulating levels of corticosterone.

Sexually experienced male rats were injected IP with 0, 0.3, 1.5, 3.0, or 6.0 mg/kg cadmium chloride. The highest dose was fatal within 48 h of injection. A dose-related deficit in erectile function was observed in ex copula tests 48 h after injection. Copulatory dysfunction was evident in mating tests 72 h after injection. Hepatic mixed function oxidase activity after 0.3 mg/kg injections was not different from controls, but was diminished by 50% in rats treated with 3.0 mg/kg. The higher cadmium doses (1.5 and 3.0 mg/kg) were associated with equivalent and marked reductions in circulating testosterone levels, and lesser decrements in circulating corticosterone levels. The rats treated with 1.5 or 3.0 mg/kg cadmium chloride lost weight (32 +/- 12 and 39 +/- 9 g, respectively). Relative decapsulated adrenal gland weights were markedly increased in rats treated with 3.0 mg/kg. These data indicate that exposure to cadmium is associated with alterations in sexual, hepatic, and adrenal function, with erectile dysfunction occurring at the lowest dose. The effects on copulatory behavior are especially striking because it requires some weeks for copulatory behavior to wane following castration.

Adrenal Glands↗

PubMed1993

Localization of rap1 and rap2 proteins in the gelatinase-containing granules of human neutrophils.

The subcellular localization of rap proteins in resting human neutrophils was investigated by immunoblot analysis with specific anti-rap2 and anti-rap1 antibodies of the membrane proteins obtained from distinct subcellular fractions. Rap2 protein was mainly located in gelatinase-containing granules, whereas rap1 protein was detected both in gelatinase-containing granules and in fractions enriched in plasma membrane. Neither rap1 nor rap2 proteins were found in the cytosol or in azurophilic granules. Rap2B, not rap2A, appeared to be the major rap2 protein in human neutrophils. The identification and subcellular localization of rap1 and rap2 proteins at the membranes of gelatinase-rich granules suggest that these proteins could play a role in the regulation of the rapid and selective mobilization of gelatinase-containing granules in human neutrophils.

Amino Acid Sequence↗