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C Rodriguez

Publications and source records attributed to C Rodriguez.

At least 37 records · Page 2Linked to original sources
PubMed1991

Normally saprobic cryptococci isolated from Cryptococcus neoformans infections.

We report two cases in which Cryptococcus laurentii was isolated from surgically resected pulmonary lesions but the cryptococcal cells is tissue reacted positively with a specific fluorescent antibody (FA) conjugate for Cryptococcus neoformans. Both patients had no apparent host defense defects. In both cases, multiple cryptococcal isolates were obtained from tissue, and yeastlike cells consistent with C. neoformans were seen in direct histology. The isolates were identified by assimilation patterns and standard procedures including phenoloxidase reactions. Since C. laurentii was consistently isolated by using stringent procedures, it was considered unlikely that the fungus represented surgical or laboratory contamination. Its presence may be the result of dual infection not detected by FA, but other possible explanations exist. The results show the value of the FA test in diagnostic mycology and call into question previous reports of cryptococci other than C. neoformans as agents of infection.

Adult↗
PubMed1991

Identification of the multidrug resistance-related membrane glycoprotein as an acceptor for cyclosporine.

The immunosuppressive agent cyclosporine A (CSA) has been shown to reverse multidrug resistance (MDR) in malignant cells. In the present study, a 3H-cyclosporine diazirine analogue (3H-PL-CS) was used to photolabel viable MDR cells. The 170 kDa membrane P-glycoprotein, which functions as a drug efflux pump, was strongly labeled. The binding of 3H-cyclosporine diazirine analogue to P-glycoprotein was competable by excess cyclosporine A and by the nonimmunosuppressive cyclosporine H. These results suggest that cyclosporine reverses the MDR phenotype by binding directly to P-glycoprotein and that this binding is not dependent on the immunosuppressive potential of the cyclosporine derivative. The identification of P-glycoprotein as a cyclosporine binding protein has obvious implications for cancer chemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1991

Human in vivo-induced spontaneous IgG-secreting cells from tonsil, blood and bone marrow exhibit different phenotype and functional level of maturation.

The subset of human spontaneous IgG-secretion cells consists of mature B lymphocytes which are capable of active and high rate IgG production in vitro without the need for additional stimuli. Therefore, such a cell subset provides a useful model for studying the terminal stages of B-cell maturation. The present work analyses the phenotypic and functional characteristics of spontaneous IgG secreting cells obtained from tonsil, blood and bone marrow. The tonsilar cell subset was CD9+ CD20+ CD19+ CD38+/-, the blood cell subset CD9- CD20- CD19+ CD38+/- and bone marrow cells were CD9- CD20- CD19+/- CD38+. The three cell subsets required de novo RNA and protein synthesis for IgG secretion to occur. Tonsilar and blood, but not bone marrow, subsets also required DNA synthesis to undergo IgG secretion. Kinetics studies revealed that IgG production by tonsil and blood cells reached a plateau after 3 days of culture. In contrast, the bone marrow cell subset secreted IgG in a linear fashion for 2 weeks. These results indicate that spontaneous IgG-secreting cells from different organs exhibit functional and phenotypic heterogeneity.

Antigens, Surface↗
PubMed1990

Phospholipase A2 activation and autoinduction of tumor necrosis factor gene expression by tumor necrosis factor.

Tumor necrosis factor (TNF) acts via a cell surface receptor to induce a variety of cellular events including cytolysis, differentiation, and mitogenesis. The mechanisms underlying the cell specific actions of TNF are not known. In the present study, postreceptor events associated with the autoinduction of TNF expression were examined in HL-60 cells. There was no detectable alteration in phospholipase C activity as measured by inositol phosphate generation or release of choline metabolites following TNF stimulation. However, TNF increased the release of arachidonic acid metabolites from HL-60 cells. This increase in arachidonic acid metabolism was associated with a 40% increase in phospholipase A2 activity. Furthermore, the release of arachidonic acid metabolites was blocked by inhibitors of phospholipase A2. Taken together, these findings indicated that TNF stimulates phospholipase A2 and arachidonic acid metabolism in HL-60 cells. The results also demonstrate that TNF expression is induced 15-30 min after stimulation with TNF and that this effect is associated with an increase in the rate of TNF transcription. This autoinduction of TNF mRNA was blocked by inhibitors of phospholipase A2. While the cyclooxygenase inhibitor indomethacin had no detectable effect, ketoconazole and nordihydroguaiaretic acid, inhibitors of lipoxygenase, also blocked the induction of TNF expression by TNF. These findings suggest that phospholipase A2 and lipoxygenase activity are required for the transcriptional activation of TNF gene expression associated with TNF stimulation of HL-60 cells.

Acetophenones↗
PubMed1990

Distribution of carboxypeptidase H messenger RNA in rat brain using in situ hybridization histochemistry: implications for neuropeptide biosynthesis.

Carboxypeptidase H is an exopeptidase which is highly specific for C-terminal basic amino acids and thought to play a role in neuropeptide biosynthesis. The distribution of carboxypeptidase H mRNA was examined in adult rat brain using in situ hybridization histochemistry. Enzyme transcripts were detected in all major brain areas. Very high levels of carboxypeptidase H mRNA were found in the hippocampus associated with pyramidal cells. Other brain regions showed varied levels of labelling, ranging from high levels in the magnocellular cells of hypothalamic nuclei to very low levels in the striatum. The appearance of enzyme transcripts throughout brain supports a role for this enzyme in the biosynthesis of many neuropeptides. The expression of transcripts in certain ventricular ependymal cells identified them as a new potential peptidergic cell type. The variations in levels of expression of carboxypeptidase H mRNA may reflect differences in peptidergic activity in different neuronal systems.

Animals↗
PubMed1990

Emergency department deaths.

This study reviews 186 deaths resulting from trauma in a 2-year period in the Charity Hospital of Louisiana at New Orleans Accident Room in order to evaluate problems in prehospital and hospital resuscitative care. All subjects underwent autopsy, and only six were found to have injuries compatible with survival. Three of these were late arrivals (by transfer or self-imposed delay) and died of protracted hemorrhage. Only three deaths occurring in the Emergency Department itself were found to have been potentially preventable. The important factors in maximizing survival of trauma patients remain rapid transport; immediate, appropriate, rapid evaluation; and quick diagnosis, resuscitation, and definitive therapy. These require a well-trained emergency medical ambulance service delivering patients quickly to a hospital designed to handle trauma patients. One person, preferably a general surgeon with trauma experience, should supervise and monitor the patient continually until the resuscitation phase and all diagnostic tests are completed and definitive therapy is initiated.

Adolescent↗
PubMed1990

The purine-cytosine permease gene of Saccharomyces cerevisiae: primary structure and deduced protein sequence of the FCY2 gene product.

A 2.1 kb DNA segment carrying the purine-cytosine permease gene (FCY2) of Saccharomyces cerevisiae was sequenced, the primary structure of the protein (533 amino acids) deduced and a folding pattern in the membrane is proposed for the permease protein. Expression of the FCY2 gene product requires a functional secretory pathway and is reduced in mnn9, a mutant strain deficient in outer chain glycosylation. The FCY2 gene was mapped on the right arm of chromosome V close to the HIS1 gene.

Amino Acid Sequence↗
PubMed1989

Blockade of endothelin-induced contractions by dichlorobenzamil: mechanism of action.

Contractions of intact rat aortic rings induced by endothelin were totally inhibited by the amiloride analogue dichlorobenzamil (DCB) at concentrations known to block Na-Ca exchange (IC50 = 30 microM). Amiloride (100 microM) was ineffective. Ca-channel blockers and a K-channel opener elicited only partial inhibition. These results could indicate that the Na-Ca exchanger plays an important role in endothelin-induced contractions. Endothelin, however, had no effect on the kinetics of the exchanger, and, in addition, contractions also occurred in Na-depleted vessels. The endothelin-induced contractions produced by Ca release from intracellular pools were also completely inhibited by DCB. In fact, the latter compound was found to block contractions induced by Ca itself in the presence of Ca ionophore or detergent. We conclude that DCB acts directly on Ca-induced activation of myofilaments in smooth muscle.

Amiloride↗
PubMed1989

Comparative functional study of colostral macrophages from mothers delivering preterm and at term.

Number and function of milk macrophages (MM) from 30 healthy mothers delivering preterm (mean gestational age 33 weeks) were compared with those obtained from 92 mothers with term delivery. The average concentration of MM in colostrum did not differ in the two groups: 0.55 x 10(6)/ml (preterm) and 0.42 x 10(6)/ml (term). Preterm MM showed the same activity as term MM in all three assayed functions (phagocytosis, chemotaxis and IL-1 secretion). Phagocytic activity, and impaired migratory motility and IL-1 secretion were significantly increased both in preterm and term MM in comparison with the activity in less mature blood monocytes. Thus it appears that preterm MM are, like term MM, a fully mature tissue macrophage population and therefore we suggest that with regard to MM both preterm and term colostrum are comparable, at least in the gestational age tested.

Cell Count↗
PubMed1989

Evaluation of a competitive antibody enzyme immunoassay for specific diagnosis of Chagas' disease.

A competitive enzyme immunoassay based on the use of a monoclonal antibody (MAb) specific for "component 5" of Trypanosoma cruzi was evaluated. The antigenicity and immunogenicity of this component has been observed in natural and experimental infections. The studies were conducted in an area of Bolivia where mixed infections with Leishmania braziliensis are frequent and present a problem in the accurate diagnosis of T. cruzi infections. The specificity and sensitivity of this assay as compared to the indirect immunofluorescence and ELISA tests were demonstrated. The present test has proved to be more specific than the immunofluorescence and ELISA tests.

Animals↗
PubMed1989

Expression of cytoskeletal proteins in glial cells of dorsal root ganglia.

The localization of S-100 protein-, glial fibrillary acidic protein- and vimentin-like immunoreactivity has been studied in dorsal root ganglia of the rat using monoclonal antibodies. A positive reaction for both S-100 protein-like and vimentin-like was found in satellite and Schwann cells. In addition, some large and intermediate sized neurons also result S-100 protein-like immunoreactivity. No positive reaction for glial fibrillary acidic protein-like was observed. The authors discuss these results.

Animals↗
PubMed1989

Cathepsin D in erythroid cells.

We have detected, solubilized, and purified to near-homogeneity a membrane-bound acid protease from rabbit reticulocytes. Chemical, physical, immunological, and catalytic characterization demonstrate that the enzyme is cathepsin D. With cytochrome b5 as substrate, the enzyme shows a surprisingly high pH optimum and is stimulated by ATP and DPG. Possible roles for the protease include protein processing of microsomal enzymes, degradation of subcellular organelles, and destruction of excess hemoglobin chains. The possible role of cathepsin D in protein processing of microsomal enzymes will be best assessed by the molecular biological approaches described in the following two presentations.

Adenosine Triphosphate↗
PubMed1989

The erythrocyte density test (EDT) and erythrocyte creatine concentration (ECE) as laboratory indexes of perinatal hypoxia.

To study the influence of gestational age and asphyxia on the behaviour of EDT and ECE a group of cuban control and asphyxiated newborns was investigated. A total number of 203 newborns at the age of 0-3 days of life, all with adequate weight for gestational age, were classified into 4 groups according to their gestational age, the 1 min and 5 min Apgar score and the presence of meconium stained amniotic fluid and/or respiratory distress syndrome immediately after birth. In the group of asphyxiated newborns higher values for both parameters were found when they were compared with the respective control groups (p less than 0.05). These techniques could help the neonatologists to more precisely identify newborns with severe perinatal asphyxia and to improve the prognosis of the outcome.

Asphyxia Neonatorum↗
PubMed1988

Iron deficiency anemia and steady-state work performance at high altitude.

Thirty-seven young adult male highland residents at 3,600-4,100 m in La Paz, Bolivia, performed short-duration cycle ergometry at 60, 80, and 100% of maximal voluntary O2 consumption (VO2max). Three groups of subjects representing the high-altitude population mean hemoglobin (Hb), the 10th percentile Hb, and below the 1st percentile were examined to test the hypothesis that the relationship of exercise performance to Hb concentration is similar to those relationships established at low altitude. Anemic individuals (n = 8) had 23% lower voluntary VO2max and 28% lower maximal work loads compared with controls (n = 17) or marginally anemic subjects (n = 12) although the relationship of VO2 to work load was similar. Anemic individuals maintained significantly higher arterial O2 partial pressures and Hb saturations during heavy exercise (90 +/- 0.5 vs. 85 +/- 0.6%) in conjunction with a greater heart rate up to maximal effort. A significantly decreased erythrocyte 2,3-diphosphoglycerate (2,3-DPG)-to-Hb molar ratio (0.70 +/- 0.04 vs. 1.12 +/- 0.06), suggestive of a left-shifted dissociation curve in anemics, is in contrast to the expected right-shifted curve. Moderate anemics were similar to controls. Anemic individuals did not differ in arterial lactate concentration from controls at absolute work loads; anemics had significantly lower arterial lactate concentrations at maximal effort than controls with no differences in the work load-to-lactate relationship. In conclusion, O2 transport during exercise at high altitude seems unaffected by the Hb concentrations as low as the 10th percentile of the population mean.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗