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J J Ríos

Publications and source records attributed to J J Ríos.

17 recordsLinked to original sources
PubMed2005

Solid-phase extraction gas chromatography-ion trap-mass spectrometry qualitative method for evaluation of phenolic compounds in virgin olive oil and structural confirmation of oleuropein and ligstroside aglycons and their oxidation products.

Phenolic compounds in Spanish virgin olive oil were analyzed by GC-MS after an SPE diol cartridge extraction and clean-up procedure. Posterior derivatization to trimethylsilyl (TMS) ethers using a mixture of hexamethyldisilazane:dimethylclorosilane (HMDS:DMCS) in pyridine (3:1:9) was performed. Several compounds were detected and 21 of them were identified. Free phenols such as hydroxytyrosol, tyrosol, tyrosyl and hydroxytyrosyl acetate, and aldehydic and dialdehydic forms of elenolic acid linked to tyrosol and hidroxytyrosol were the most abundant compounds. Likewise, oxidation products coming from the aldehydic and dialdehydic forms of elenolic acid, and of ligstroside and oleuropein aglycons, were detected, and their structure confirmed by other mass spectrometry technique, i.e., HPLC-APCI-MS. Individual oxidation products were isolated from an oxidized sample by preparative HPLC, converted to TMS ethers and re-analyzed by GC-MS. When necessary and for identification purposes, selective ion monitoring, namely, GC-MS-SIM, was employed. This is the first time that structures of oxidized forms are determined by GC-MS.

Gas Chromatography-Mass Spectrometry↗
PubMed2003

Main polyphenols in the bitter taste of virgin olive oil. Structural confirmation by on-line high-performance liquid chromatography electrospray ionization mass spectrometry.

Twenty virgin olive oils of extra quality and different bitter intensity were submitted to sensory evaluation and to the determination of polyphenols. A linear regression analysis was carried out assuming, as an independent variable, bitter intensity perceived by tasters, as an independent variable, the concentration (mmol/kg) of dialdehydic and aldehydic forms oleuropein aglycon, and dialdehydic and aldehydic forms ligstroside aglycon. Structural confirmation of these compounds was done by online high-performance liquid chromatography-electrospray ionization-collison-induced dissociation-mass spectrometry. The results obtained demonstrate the essential role played by this compound in the bitter taste of virgin olive oil.

Chromatography, High Pressure Liquid↗
PubMed2003

Achromobacter xylosoxidans bacteremia: a 10-year analysis of 54 cases.

Fifty-four cases of Achromobacter xylosoxidans bacteremia diagnosed over a 10-year period in patients from 2 months to 87 years of age were reviewed. Fifty-two episodes were nosocomial. The most frequent underlying condition was neoplasm (solid or hematological). The source of infection was a contaminated intravenous catheter in 35 patients (60%) and pneumonia in 6 patients. Eight (15%) patients died. The only risk factors significantly associated with mortality were age over 65 years and neutropenia. The results of in vitro susceptibility studies of the isolates showed that antibiotic therapy with antipseudomonal penicillins or carbapenems would be a reasonable choice. An epidemiological study conducted in the hemodialysis unit showed Achromobacter xylosoxidans in tap water and on the hands of two healthcare workers but not in the hemodialysis systems. Patients were probably contaminated when healthcare workers manipulated the intravenous catheters without wearing gloves.

Adolescent↗
PubMed2003

Pancreatic ascites: study of therapeutic options by analysis of case reports and case series between the years 1975 and 2000.

OBJECTIVE: Because of the low incidence of pancreatic ascites, only case reports and case series have been published, and no randomized controlled trials have been performed to find out which is the best therapeutic approach. The aim of this study was to evaluate the utility of the different treatments for pancreatic ascites by a thorough review of all case reports described in the literature in which an independent analysis of the efficacy of the treatment administered to each patient is possible. METHODS: We conducted an analysis of all case reports and case series of pancreatic ascites published between 1975 and 2000 in which clinical data of every patient could be identified individually. A total of 139 cases were studied. Clinical characteristics, treatments administered, and response to therapy of every patient were registered. Conservative therapy included drainage of ascitic fluid, total parenteral nutrition and diet, and somatostatin analogues. Interventional therapy was either endoscopic or surgical. RESULTS: After multivariate analysis, the only treatments related to success were surgery (adjusted OR = 8.2, 95% CI = 3.0-22.9) and transpapillary stent (adjusted OR = 7.3, 95% CI = 0.8-62.9). No significant relationship was found between failure or death and the use of other treatments, age, sex, year of publication, underlying disease, site of leakage, or serum amylase levels. The apparent lack of effect of somatostatin analogues could be attributed to the small number of cases and the heterogeneity of the dosages. CONCLUSIONS: Conservative therapy is not advisable for pancreatic ascites because of the high proportion of failures. Interventional therapy with surgery or transpapillary stent has a positive effect in the clinical outcome.

Adolescent↗
PubMed2002

Sebaceus naevi: a clinicopathologic study.

OBJECTIVE: To analyse sebaceus naevus (SN) incidence, associated malignancies, and developmental defects in a retrospective study. METHODS: We retrospectively analysed all cases of SN excised in our Department over a 20-year period. All cases of epidermal naevus syndrome (Schimmelpenning syndrome) associated with SN were recorded, as well as all patients with histological changes suggesting degeneration of the initial SN. RESULT: A total 226 patients with SN were included in the study. Stage II was the most common (65%), and the parietal area was the most common location of SN (42%), with only 7% located in non-scalp areas. Syringocystadenoma papilliferum and trichoblastoma were the most common tumours arising on SN. We only found five patients with basal cell carcinoma arising on previous SN. Epidermal naevus syndrome associated with SN was diagnosed in 16 patients, and this was the most common neurocutaneous association. CONCLUSION: The incidence of malignancy arising on SN was very low, indicating that prophylactic surgery of NS in children is not recommendable. Developmental defects should be investigated in order to evidence possible epidermal naevus syndrome associated with SN.

Adolescent↗
PubMed2002

Identification of a hydratase and a class II aldolase involved in biodegradation of the organic solvent tetralin.

Two new genes whose products are involved in biodegradation of the organic solvent tetralin were identified. These genes, designated thnE and thnF, are located downstream of the previously identified thnD gene and code for a hydratase and an aldolase, respectively. A sequence comparison of enzymes similar to ThnE showed the significant similarity of hydratases involved in biodegradation pathways to 4-oxalocrotonate decarboxylases and established four separate groups of related enzymes. Consistent with the sequence information, characterization of the reaction catalyzed by ThnE showed that it hydrated a 10-carbon dicarboxylic acid. The only reaction product detected was the enol tautomer, 2,4-dihydroxydec-2-ene-1,10-dioic acid. The aldolase ThnF showed significant similarity to aldolases involved in different catabolic pathways whose substrates are dihydroxylated dicarboxylic acids and which yield pyruvate and a semialdehyde. The reaction products of the aldol cleavage reaction catalyzed by ThnF were identified as pyruvate and the seven-carbon acid pimelic semialdehyde. ThnF and similar aldolases showed conservation of the active site residues identified by the crystal structure of 2-dehydro-3-deoxy-galactarate aldolase, a class II aldolase with a novel reaction mechanism, suggesting that these similar enzymes are class II aldolases. In contrast, ThnF did not show similarity to 4-hydroxy-2-oxovalerate aldolases of other biodegradation pathways, which are significantly larger and apparently are class I aldolases.

Aldehyde-Lyases↗
PubMed2001

Determination of phenols, flavones, and lignans in virgin olive oils by solid-phase extraction and high-performance liquid chromatography with diode array ultraviolet detection.

A simple analytical method for the quantitative determination of phenols, flavones, and lignans in virgin olive oils was developed. The polar fraction was isolated from small amounts of oil sample (2.5 g) by solid-phase extraction (SPE) using diol-phase cartridges, and the extract was analyzed by reversed-phase HPLC coupled with diode array UV detection. Chromatographic separation of pinoresinol, cinnamic acid, and 1-acetoxypinoresinol was achieved. Repeatability (RSD < 6.5%), recovery (> 90%), and response factors for each identified component were determined. SPE on amino-phase cartridges was used for isolating acidic phenols and as an aid for phenol identification. For the first time, 2-(4-hydroxyphenyl)ethyl acetate was detected in olive oils. The aldehydic structure of the ligstroside aglycon was confirmed by NMR spectroscopy. The colorimetric determination of total o-diphenolic compounds by reaction with molybdate was consistent with their HPLC determination. Differences between results obtained by liquid-liquid extraction and SPE were not statistically significant.

Chromatography, High Pressure Liquid↗
PubMed2001

Erosive pustular dermatosis of the scalp after skin grafting.

Erosive pustular dermatosis of the scalp is a rare condition of unknown etiology that usually occurs in the elderly and is characterized by pustules that appear on the scalp leading to scarring alopecia. The histopathology is not specific. Its onset has been related with previous trauma on the scalp. Only three cases after skin grafting have been reported. We describe a case of erosive pustular dermatosis of the scalp appearing on a split-thickness skin graft placed after excision of a basal cell carcinoma.

Basal Cell Carcinoma↗
PubMed2001

Fever of unknown origin: classic and associated with human immunodeficiency virus infection. a comparative study.

Fever of unknown origin (FUO) associated with HIV infection is different from classic FUO. Relevant etiologies, procedures and time to diagnosis were analyzed. Patients admitted with FUO from 1991 to 1996 were prospectively followed. Thirty with classic FUO (group I) and 46 with FUO and HIV (group II) were included. Data on diagnosis, time to achieve it, and procedures were registered. Diagnosis was obtained in 87% and 93% of cases in groups I and II. Infections were the most frequent cause in group II. Collagen diseases were found in group I and absent in group II. Prevalence of neoplasia was similar. Mean time to diagnosis was near 5 weeks. In HIV the predominant diagnostic method was the Lowenstein culture. Invasive methods were similarly employed. It is concluded that predominance of Mycobacteria and absence of collagen diseases make FUO associated with HIV a different form of FUO. No differences were found in approach and time to diagnosis.

Adult↗
PubMed1999

Effects of ozone treatment on postharvest strawberry quality.

The effect of ozone treatment on the postharvest quality of strawberry was evaluated. Strawberry fruits (Fragaria x ananassa Duch. cv. Camarosa) were stored at 2 degrees C in an atmosphere containing ozone (0.35 ppm). After 3 days at 2 degrees C, fruits were moved to 20 degrees C to mimic retail conditions (shelf life). The changes in several quality parameters such as fungal decay, color, sugar and acids distribution, and aroma were evaluated during the strawberries' shelf life. Ozone treatment was ineffective in preventing fungal decay in strawberries after 4 days at 20 degrees C. Significant differences in sugars and ascorbic acid content were found in ozone-treated strawberries. At the end of cold storage, the vitamin C content of ozonated strawberries was 3 times that of control fruits. A detrimental effect of ozone treatment on strawberry aroma was observed, with a 40% reduced emission of volatile esters in ozonated fruits.

Acetaldehyde↗
PubMed1993

Epidermotropic metastasis coexisting with multiple primary cutaneous malignant melanomas.

A 45-year-old male, with a history of malignant melanoma on the thorax excised 4 years ago, presented a sudden eruption of more than 300 pigmented lesions. Fifteen excisions of tumors in different stages were carried out on four different dates. Dermatopathological examinations revealed features of primary as well as metastatic malignant melanomas. We suggest that besides the extensive dissemination there was also an activation of the resting melanocytes, that led to the formation of multiple primary melanomas.

Epidermis↗