Publications by authors named "Joaquin Diaz"

Interfacial esterases are useful enzymes in bioconversion and racemic mixture resolution processes. Marine invertebrates are few explored potential sources of these proteins. In this work, aqueous extracts of 41 species of marine invertebrates were screened for esterase, lipase, and phospholipase A activities, being all positive.

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Objective: This study aimed to evaluate the changes in the VOR gain after intratympanic gentamicin therapy and to correlate them with the mid-term effects on the control of vertigo, in a population of Menière's disease patients.

Study Design: The study design was a prospective "Outcomes research."

Setting: Tertiary referral center.

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Sticholysin I and Sticholysin II (StI and StII) are two potent hemolysins which form pores in natural and model membranes at nanomolar concentrations. These proteins were purified from the aqueous extract of the sea anemone Stichodactyla helianthus, Ellis 1768, by gel filtration and ionic exchange chromatography. This procedure rendered StI and StII with high purity (purification factors: 36 and 50, respectively) but a low yield of hemolytic activity, HA (<3%).

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This study describes a novel bifunctional metallocarboxypeptidase and serine protease inhibitor (SmCI) isolated from the tentacle crown of the annelid Sabellastarte magnifica. SmCI is a 165-residue glycoprotein with a molecular mass of 19.69 kDa (mass spectrometry) and 18 cysteine residues forming nine disulfide bonds.

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Pichia pastoris is a highly successful system for the large-scale expression of heterologous proteins, with the added capability of performing most eukaryotic post-translational modifications. However, this system has one significant disadvantage - frequent proteolytic degradation by P. pastoris proteases of heterologously expressed proteins.

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After screening 25 marine invertebrates, a novel metallocarboxypeptidase (SmCP) has been identified by activity and MS analytical approaches, and isolated from the marine annelid Sabellastarte magnifica. The enzyme, which is a minor component of the molecularly complex animal body, as shown by 2D gel electrophoresis, has been purified from crude extracts to homogeneity by affinity chromatography on potato carboxypeptidase inhibitor and by ion exchange chromatography. SmCP is a protease of 33792 Da, displaying N-terminal and internal sequence homologies with M14 metallocarboxypeptidase-like enzymes, as determined by MS and automated Edman degradation.

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We analyzed the efficacy of imipenem/cilastatin alone (group I, 197 patients) or in combination with a glycopeptide (group I + G, 231 patients) as first-line antibiotic therapy for 2 consecutive cohorts of autologous stem cell transplantation (ASCT) recipients with febrile neutropenia. From June 2001 to June 2002, patients received imipenem/cilastatin (500 mg/6 hours), and from July 2002 to December 2003, they received imipenem/cilastatin as for group I plus a glycopeptide (vancomycin, 1 g/12 hours or teicoplanin, 400 mg/day). Fever of unknown origin accounted for 33.

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Therapeutic vaccination of mice bearing melanoma tumors with our genetically modified tumor cells, via DOTAP/GM-CSF lipoplexes, results in >85% tumor growth inhibition. These fresh transfected cells (irradiated, frozen and thawed) are able to produce high amounts of GM-CSF transgene (>200 ng/10(6) cells/24 h). After vaccination, significant increases (>eight-fold) in specific antitumor membrane protein IgG1 and IgG2a are obtained only in groups vaccinated with GM-CSF-producing cells, where also the highest rates of tumor inhibition, and significantly delayed mice death (P<0.

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We report that 100% mice survival after tumor challenge is achieved with cytokine-engineered cells employing nonviral lipoplexes and without using viral vectors. We describe this effect with cytokine-secreting tumor cell vaccines, based on cell clones or fresh transfected cells. Tumor cells were transfected with murine granulocyte-macrophage colony-stimulating factor (GM-CSF) or IL-4 plasmids employing the cationic lipid DOTAP, were irradiated (150 Gy) and kept frozen until use.

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An inhibitor of the metallo-ectoenzyme, pyroglutamyl aminopeptidase II (PPII), a thyrotropin releasing hormone-specific peptidase, was identified by screening extracts from marine species of the Cuban coast-line belonging to the phylla Chordata, Echinodermata, Annelida, Mollusca, Cnidaria, Porifera, Chlorophyta and Magnoliophyta. Isolation of the inhibitor (HcPI), from the marine annelide Hermodice carunculata, was achieved by trichloroacetic acid treatment of the aqueous extract, followed by ion-exchange chromatography on DEAE Sephacel, gel filtration on Sephadex G-25 and reverse phase-HPLC. HcPI had a small apparent molecular weight (below 1000 Da) and was not a peptide.

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