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Biomedical subjects

I González

Publications and source records attributed to I González.

At least 19 recordsLinked to original sources
PubMed2000

Reversibility of morphine effects on phagocytosis by murine macrophages.

Proneness of addicts to infections may be partially due to opiate effects on immune cells. We find that acute morphine inhibits phagocytosis in murine peritoneal macrophages in vitro with apparent desensitization at high concentrations, whereas chronic exposure results in a state akin to tolerance/dependence where macrophages seem to require morphine to phagocytize at a control level. However, both putative desensitization and tolerance/dependence are reversible, since drug re-addition several hours after withdrawal results in inhibition, as in acute exposure. This shows that opiate effects on immune cells are variably related to the experimental context in which they are administered, which is of relevance for understanding their potential role in immunosuppression.

Animals↗
PubMed2000

The periodontal abscess (I). Clinical and microbiological findings.

BACKGROUND/AIMS: Little information is available regarding the diagnosis and microbiology of periodontal abscesses. The aim of this descriptive clinical and microbiological study was to provide more information in order to help in the characterisation of the periodontal abscess associated to periodontitis. METHOD: 29 consecutive patients with a periodontal abscess were studied by the assessment of clinical variables, including both subjective (pain, edema, redness and swelling) and objective (bleeding on probing, suppuration, probing pocket depth, tooth mobility and cervical lymphadenopathy) parameters. Microbiological samples were taken for anaerobic microbiology and processed by means of culture. Systemic involvement was also studied through the analysis of blood and urine samples using conventional laboratory standards. RESULTS: 62% of the abscesses affected untreated periodontitis patients, and 69% were associated with a molar tooth. More than 75% of the abscesses had moderate-severe scores related to edema, redness and swelling, and 90% of the patients reported pain. Bleeding occurred in all abscesses, while suppuration on sampling was detected in 66%. Mean associated pocket depth was 7.28 mm, and 79% of teeth presented some degree of mobility. Cervical lymphadenopathy was seen in 10% of patients, while elevated leucocyte counts were observed in 31.6%. The absolute number of neutrophils was elevated in 42% of the patients. High prevalences of putative periodontal pathogens were found, including Fusobacterium nucleatum, Peptostreptococcus micros, Porphyromonas gingivalis, Prevotella intermedia and Bacteroides forsythus. CONCLUSIONS: The periodontal abscess has clear clinical characteristics and is usually associated with severe periodontal destruction. This condition may cause systemic involvement and the lesion generally has a large bacterial mass with a high prevalence of well-recognised periodontal pathogens.

Acute Disease↗
PubMed2000

Development of a combined PCR-culture technique for the rapid detection of Arcobacter spp. in chicken meat.

A combined PCR-culture technique was developed to detect Arcobacter spp. in fresh chicken meat. Following a short selective enrichment of chicken samples, bacterial DNA was extracted and amplified using primers targeted at the genes encoding 16S rRNA of Arcobacter spp. The selected primers amplify a 181-bp fragment from all Arcobacter spp., whereas no PCR product is generated for other bacteria, including the closely related Campylobacter and Helicobacter species. The assay was used to screen 96 retail-purchased chicken samples for the presence of Arcobacter spp. Fifty-three percent of the samples analysed were positive for this micro-organism. The assay is simple and sensitive and reduces the amount of time required to positively detect Arcobacter spp. in poultry meat.

Animals↗
PubMed1999

Thermal inactivation of Bacillus cereus spores formed at different temperatures.

The effects of the sporulation temperature in the range 20-45 degrees C on the D and z values of three isolates of Bacillus cereus (ATCC 4342, 7004 and 9818) were investigated. The strains were found to differ in their response. Higher D100 values (around 10-fold) were obtained with isolates 4342 and 9818 when the sporulation temperature increased from 20 to 45 degrees C. With isolate 7004 (the least heat resistant of the three strains), however, the most thermal tolerant spores were obtained at 35 degrees C. The z values were not significantly modified (P > 0.05) by the sporulation temperature. Mean z values of 7.46+/-0.22 degrees C for isolate 4342, 7.80+/-0.40 degrees C for 7004 and 8.09+/-0.33 degrees C for 9818 were obtained.

Bacillaceae Infections↗
PubMed1999

Identification of sole (Solea solea) and Greenland halibut (Reinhardtius hippoglossoides) by PCR amplification of the 5S rDNA gene.

Polymerase chain reaction (PCR) amplification of the nuclear 5S rDNA gene, has been used for the identification of sole (Solea solea) and Greenland halibut (Reinhardtius hippoglossoides). Two species-specific primers were designed to amplify specific fragments of the 5S rDNA gene in each species. The remarkably different size of the amplicons obtained gives, by simple agarose gel electrophoresis, two distinguishable band patterns for both flatfish species. This genetic marker can be very useful for the accurate identification of S. solea and Greenland halibut, to enforce labeling regulations.

Animals↗
PubMed1999

Ecological approach of macrolide-lincosamides-streptogramin producing actinomyces from Cuban soils.

We report in this study the frequency of Streptomyces strains to produce macrolide-lincosamide-streptogramin (MLS) antibiotics isolated from Cuban soils. The screening assay is based on the induction of MLS-resistance phenotype in a clinical isolated strain of Staphylococcus aureus S-18. Our results suggest that of 800 Streptomyces strains isolated from different soil samples, 6% were positives in the screening test used. The ferralitic red soil from Pinar del Río (north) provided the major percentage (3.6%) of MLS producing strains. The other soil samples tested belonging to Guira de Melena and Bauta in Havana, Matanzas City, Topes De Collantes (Villa Clara), and Soroa Mountains (Pinar del Rio) hill reached very low percentages.

Anti-Bacterial Agents↗
PubMed1999

Rapid enumeration of Escherichia coli in oysters by a quantitative PCR-ELISA.

Direct enumeration of Escherichia coli from oysters was achieved using a polymerase chain reaction (PCR) amplification of the lamB gene coupled with an enzyme-linked immunosorbent assay (ELISA). Amplified PCR products generated using a digoxigenin-labelled primer were heat denatured before being quantified by an ELISA. A biotinylated probe immobilized onto streptavidin-coated microplates was used to capture the digoxigenin-labelled fragments that were detected with a peroxidase antidigoxigenin conjugate. Subsequent enzymic conversion of substrate gave distinct absorbance differences when assaying oyster samples containing E. coli in the range 10-10(5) cfu g-1.

Animals↗
PubMed1999

New genus-specific primers for the PCR identification of members of the genera Pseudonocardia and Saccharopolyspora.

Members of the family Pseudonocardiaceae are difficult to identify on the basis of their micromorphology only. The biochemical characterization of each new isolate is a painstaking and time-consuming task which cannot always be undertaken when handling large numbers of strains as is the case in natural product screening programmes. In this study, two sets of genus-specific oligonucleotides were designed which allow rapid detection of members of the genera Pseudonocardia and Saccharopolyspora by means of PCR-specific amplification. The genus specificity of these primers was validated on a wide range of collection strains and the primers were subsequently used to study a group of 106 wild-type isolates that possessed morphological characteristics of the family. Out of this group, 51 strains could be identified as members of the genus Pseudonocardia and only nine isolates could be assigned to the genus Saccharopolyspora. The diversity indicated by whole-cell fatty acid profiles of both wild-type and reference strains was compared with that identified using the oligonucleotide primers. The partial 16S rDNA sequencing of representative wild-type strains was used to validate their genus assignment by PCR-specific amplification. This study shows the industrial usefulness of the application of these direct identification tools as well as the complementary use of two sources of data, PCR-specific amplification results and fatty acid composition, to assess the diversity of a microbial population.

Actinomycetales↗
PubMed1999

p53 and K-ras gene mutations correlate with tumor aggressiveness but are not of routine prognostic value in colorectal cancer.

PURPOSE: p53 gene and K-ras mutations are among the most common genetic alterations present in colorectal cancer. The prognostic utility of such mutations remains controversial. The purpose of this study was to prospectively evaluate the prognostic significance of p53 and K-ras gene mutations in colorectal cancer. PATIENTS AND METHODS: One hundred forty patients were analyzed. Tumors belonging to the microsatellite mutator phenotype were excluded (n = 8). Mutations at the K-ras and p53 genes were detected and characterized by restriction fragment length polymorphism, single-strand conformation polymorphism, and sequencing, as appropriate. RESULTS: p53 mutations were detected in 66 (50%) and K-ras mutations were detected in 54 (41%) of the 132 patients. In 26 cases (20%), ras and p53 mutations coexisted; in 38 cases (29%), neither mutation was found. Multivariate analysis of the whole population analyzed (n = 132) showed that survival was strongly correlated with the presence of p53 mutations alone or in combination with K-ras mutations (P = .002; log-rank test). When only patients undergoing a radical resection were considered (R0; n = 101), p53 mutations were no longer of prognostic significance. CONCLUSION: p53 mutations alone or in combination with K-ras mutations are correlated with a worse outcome. However, the routine use of these mutations as prognostic markers in the clinical setting is not recommended.

Adult↗
PubMed1999

Indirect enzyme-linked immunosorbent assay for the identification of sole (Solea solea), European plaice (Pleuronectes platessa), flounder (Platichthys flesus), and Greenland halibut (Reinhardtius hippoglossoides).

Polyclonal antibodies produced against soluble muscle protein extracts from sole (Solea solea), European plaice (Pleuronectes platessa), flounder (Platichthys flesus), and Greenland halibut (Reinhardtius hippoglossoides) were used in an indirect enzyme-linked immunosorbent assay for the specific identification of fillets from these flatfish species. The assay was performed in two different formats: microtiter plates and immunostick tubes. Immunorecognition of antibodies adsorbed to their specific fish samples was made with goat antirabbit immunoglobulins conjugated to the enzyme horseradish peroxidase. Subsequent enzymatic conversion of the substrate allowed unequivocal identification of all flatfish species studied.

Animals↗
PubMed1999

[Isolation, identification and serotyping of yeasts obtained from the vaginal fluid in patients with clinical vaginitis].

A study was carried out to determine the presence of Candida in 105 patients with clinical vaginitis who consulted in the Infectious Disease Unit of the Vargas Hospital after referral from Gynecology Service. Yeasts were detected in 23 cases (24%), and identified as C. albicans (12), C. tropicalis (5), C. guilliermondii (3), C. glabrata (2) and C. parapsilosis (1). The presence of hyphae was observed in 50% of the direct examinations, in which the isolated species was C. albicans. These structures were not observed in infections with other species of Candida. In this study, there was relatively little difference between the percentages of serotypes A and B, 58 % and 42, respectively. This is in contrast with previous studies reported in clinical material from Venezuela and other countries, in which serotype A presented a greater incidence than serotype B. Our observations suggest an increase in serotype B C. albicans in vaginal candidiasis.

Adolescent↗
PubMed1998

Congenital chondromyxoid fibroma of the ethmoid: case report.

This report describes a congenital case of chondromyxoid fibroma (CMF) arising from the ethmoid bone. We believe it to be the second case of congenital CMF that has been documented, and the third case of CMF arising in the ethmoid. We describe the radiographic features of this rare entity and indicate the necessity for careful correlation between radiographic and histological findings to distinguish CMF from chondrosarcoma.

Chondroblastoma↗
PubMed1998

Quantitative detection of meat spoilage bacteria by using the polymerase chain reaction (PCR) and an enzyme linked immunosorbent assay (ELISA).

A quantitative PCR-ELISA for the rapid enumeration of bacteria in refrigerated raw meat has been developed using primers designed from conserved regions in the 16S ribosomal RNA gene (rRNA). Amplified PCR products generated using a digoxigenin-labelled primer were automatically hybridized to a biotinylated probe included in the PCR reaction. The hybridization was performed as part of the PCR programme. The biotin-digoxigenin hybrids were quantified by an enzyme-linked immunosorbent assay (ELISA). Streptavidin bound to the wells of a microtitre plate was used to capture the biotin-digoxigenin-labelled fragments that were detected with a peroxidase anti-digoxigenin conjugate. Subsequent enzymic conversion of substrate gave distinct absorbance differences when assaying meat samples containing bacteria in the range 10(2)-10(7) cfu cm-2. The detection threshold for the PCR-ELISA assay developed in this work is 10(2) cfu cm-2.

Bacteria↗
PubMed1998

Effect of exercise on erythrocyte beta-adrenergic receptors and plasma concentrations of catecholamines and thyroid hormones in Thoroughbred horses.

The effects of exercise stress on erythrocyte beta-adrenergic receptor characteristics and plasma concentrations of adrenaline, noradrenaline and thyroid hormones were studied in Thoroughbred racehorses during rest and after exercise. Five minutes after a maximal speed race of 1200 +/- 200 m (mean +/- s.d.), both plasma adrenaline and noradrenaline concentrations increased with respect to basal values (from 2.48 +/- 0.15 to 3.83 +/- 0.27 and from 2.13 +/- 0.11 to 3.53 +/- 0.27 nmol/l respectively). The increment of adrenaline was greater in high performance (HP) as compared to low performance (LP) horses (76.9 vs. 43.5%), in accordance with the contribution of the adrenal medulla in the sympathoadrenal response to exercise. Triiodothyronine (T3), but not thyroxine (T4) levels increased 5 min after exercise (from 55.6 +/- 2.9 to 81 +/- 3.7 ng/dl and from 0.67 +/- 0.04 to 0.70 +/- 0.05 micrograms/dl respectively). No differences were observed in basal values of thyroid hormones or in the percentage of T3 increment, when comparing HP vs. LP horses. Erythrocyte membranes obtained 5 min after racing showed decreased concentrations of beta-adrenergic receptors (beta-AR) and dissociation constant as compared to basal values (50.1 +/- 7.0 vs. 95.7 +/- 12.0 fmol/mg protein and 0.97 +/- 0.24 vs. 2.04 +/- 0.3 nmol/l respectively). This temporal pattern suggest that the observed changes in beta-AR characteristics could be mediated by catecholamines, but not by thyroid hormones, in this model. This down regulation of beta-AR may act as a protecting mechanism preventing the erythrocytes from the decrease in membrane fluidity known to be provoked by adrenergic agonists. The accomplished study showed that, in the Thoroughbred horse, there is a homeostatic response to race stress, characterised by a sudden increase in plasma catecholamines and T3 and a parallel decrease in beta-AR concentration on the erythrocyte membrane. In this way the racing horse could rapidly adjust its metabolism to the exercise stress, but at the same time override one possible undesirable side-effect caused by these hormonal changes. Further studies will be required to establish performance-related differences occurring in endocrine changes.

Animals↗
PubMed1998

Fluoroquinolone resistance mutations in the parC, parE, and gyrA genes of clinical isolates of viridans group streptococci.

The nucleotide sequences of the quinolone resistance-determining regions (QRDRs) of the parC and gyrA genes from seven ciprofloxacin-resistant (Cpr) isolates of viridans group streptococci (two high-level Cpr Streptococcus oralis and five low-level Cpr Streptococcus mitis isolates) were determined and compared with those obtained from susceptible isolates. The nucleotide sequences of the QRDRs of the parE and gyrB genes from the five low-level Cpr S. mitis isolates and from the NCTC 12261 type strain were also analyzed. Four of these low-level Cpr isolates had changes affecting the subunits of DNA topoisomerase IV: three in Ser-79 (to Phe or Ile) of ParC and one in ParE at a position not previously described to be involved in quinolone resistance (Pro-424). One isolate did not show any mutation. The two high-level Cpr S. oralis isolates showed mutations affecting equivalent residue positions of ParC and GyrA, namely, Ser-79 to Phe and Ser-81 to Phe or Tyr, respectively. The parC mutations were able to transform Streptococcus pneumoniae to ciprofloxacin resistance, while the gyrA mutations transformed S. pneumoniae only when mutations in parC were present. These results suggest that DNA topoisomerase IV is a primary target of ciprofloxacin in viridans group streptococci, DNA gyrase being a secondary target.

Amino Acid Sequence↗
PubMed1998

The Cdk inhibitors p25rum1 and p40SIC1 are functional homologues that play similar roles in the regulation of the cell cycle in fission and budding yeast.

p25rum1 and p40SIC1 are specific inhibitors of p34(cdc2/CDC28) kinase complexes with B-type cyclins that play a central role in the regulation of the G1 phase of the cell cycle. We show here that low levels of expression of SIC1 in Schizosaccharomyces pombe rescues all the phenotypes of cells lacking the rum1+ gene. In addition, high level expression of SIC1 in S. pombe induces extra rounds of DNA replication without mitosis, a phenotype very similar to the overexpression of rum1+. Transient expression of rum1+ in S. cerevisiae restores the G1 arrest phenotype of cdc4 sic1Delta double mutants. Overproduction of rum1+ in Saccharomyces cerevisiae causes a cell cycle block in G1 with a phenotype similar to inactivation of all the Clb cyclins. Finally, we have mapped the cyclin interacting domain and Cdk inhibitory domain to a region of about 80 amino acids in p25rum1 that has significant homology to the C-terminal domain of p40SIC1. All these observations suggest that fission yeast p25rum1 and budding yeast p40SIC1 define a family of Cdk inhibitors that specifically down regulate cyclin B/Cdk1 during the G1 phase of the cell cycle.

Cell Cycle↗