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Biomedical subjects

I Rodriguez

Publications and source records attributed to I Rodriguez.

At least 73 records · Page 4Linked to original sources
PubMed1996

Appropriate choice of antihypertensive therapy.

A modern approach to the choice of antihypertensive therapy is discussed in this article. Since the introduction of hydralazine and reserpine in 1950, a number of compounds have been proposed for the treatment of hypertension. The 1993 report of the Joint National Committee on Hypertension established four choices: diuretics, beta blockers, ACEIs, and calcium entry blockers. Additionally, alpha and alpha-beta blockers were also recommended. Several pharmacological considerations have been discussed concerning medical therapy of hypertension. In modern therapy, the best approach is individualized therapy, in which three major principles are taken into consideration: (1) The use of diuretics, alpha blockers, beta blockers, ACEIs, or calcium entry blockers, (2) The presence of concomitant diseases, and (3) The use of substitution therapy. Several other factors are discussed such as the cost of medication, drug interactions and combinational therapy.

Antihypertensive Agents↗
PubMed1995

Induction of morphological transformation in BALB/3T3 mouse embryo cells by okadaic acid.

Okadaic acid is produced by several types of dinoflagellates (marine plankton) and has been implicated as a causative agent of diarrhoetic shellfish poisoning. Okadaic acid, a known tumour promoter in vivo, has been shown to promote morphological transformation of carcinogen-initiated BALB/3T3 cells. This study shows that okadaic acid is capable of inducing morphological transformation of BALB/3T3 cells in the absence of an initiator.

3T3 Cells↗
PubMed1994

Determination of chlorophenols in drinking water samples at the subnanogram per millilitre level by gas chromatography with atomic emission detection.

The use of an atomic emission detector following a process of preconcentration of drinking water samples by a factor of 1500:1 allows the highly selective determination of chlorophenols present in samples below the maximum limit of 0.5 ng/ml set by international regulations. The preconcentration of the samples is carried out using 0.25-g commercial graphitized carbon cartridges without the need for sample derivatization prior to solid-phase extraction.

Chlorophenols↗
PubMed1994

Localization of the gene for pigment epithelium-derived factor (PEDF) to chromosome 17p13.1 and expression in cultured human retinoblastoma cells.

The gene for pigment epithelium-derived factor (PEDF) was localized to chromosome 17 by the analysis of three independent somatic cell hybrid panels. Fluorescence in situ hybridization shows a specific hybridization signal at the terminal portion of the short arm of chromosome 17. PCR analysis of somatic cell hybrids containing specific regions of 17 was subsequently used to sublocalize PEDF to 17p13.1-pter. PEDF thus maps to a region containing a number of cancer-related loci and thus must be considered a candidate gene for these cancers. Preliminary studies with cultured human Y79 retinoblastoma cells indicate that expression of PEDF is associated with relatively undifferentiated, proliferating cells rather than their differentiated, slow-growing counterparts. This and the fact that the PEDF protein can act as a potent neurotrophic differentiating agent suggest that PEDF is linked to proliferative events that terminate in final phenotypic determination within specific cell lineages.

Animals↗
PubMed1994

Transforming activity of selected polycyclic aromatic hydrocarbons and their nitro-derivatives in BALB/3T3 A31-1-1 cells.

The transforming activities of four polycyclic aromatic hydrocarbons and six of their nitro-derivatives were studied using BALB/3T3 clone A31-1-1 cells in the absence of exogenous metabolic activation. Each compound was assayed two to four times to its maximal level of solubility. A transformation response was induced by 1-nitropyrene, 2-nitropyrene, 4-nitropyrene and benzo[a]pyrene in the BALB/3T3 mouse embryo cells. Pyrene and 7-nitrobenz[a]anthracene produced questionable responses, and benz[a]anthracene, chrysene, 6-nitrobenzo[a]pyrene and 6-nitrochrysene produced negative responses. The capacity of the assay system to indicate tumorigenicity of the test compounds is discussed.

3T3 Cells↗
PubMed1994

Overexpression of BCL-2 in transgenic mice protects neurons from naturally occurring cell death and experimental ischemia.

Naturally occurring cell death (NOCD) is a prominent feature of the developing nervous system. During this process, neurons express bcl-2, a major regulator of cell death whose expression may determine whether a neuron dies or survives. To gain insight into the possible role of bcl-2 during NOCD in vivo, we generated lines of transgenic mice in which neurons overexpress the human BCL-2 protein under the control of the neuron-specific enolase (NSE) or phosphoglycerate kinase (PGK) promoters. BCL-2 overexpression reduced neuronal loss during the NOCD period, which led to hypertrophy of the nervous system. For instance, the facial nucleus and the ganglion cell layer of the retina had, respectively, 40% and 50% more neurons than normal. Consistent with this finding, more axons than normal were found in the facial and optic nerves. We also tested whether neurons overexpressing BCL-2 were more resistant to permanent ischemia induced by middle cerebral artery occlusion; in transgenic mice, the volume of the brain infarction was reduced by 50% as compared with wild-type mice. These animals represent an invaluable tool for studying the effects of increased neuronal numbers on brain function as well as the mechanisms that control the survival of neurons during development and adulthood.

Animals↗
PubMed1994

HIV type 1 infection of human cortical neuronal cells: enhancement by select neuronal growth factors.

Neuronal cells in culture respond to neuronal growth factors by secondary cellular pathways similar to those described for activation of lymphocytes and macrophages. In HIV-1-infected T lymphocytes and in macrophages, these pathways were shown to converge on nuclear factors that bind and stimulate the HIV-1 LTR and lead to enhancement of HIV-1 expression. In the current study we have investigated whether the same mechanisms also enhance HIV-1 production by neural cells. We have demonstrated that HIV/N1T replication in HCN-1A cells, a human cortical neuronal cell line, is enhanced threefold by nerve growth factor (NGF) and by fibroblast growth factor (FGF), but not by epidermal growth (EGF) factor, or phorbol ester. HCN-1A cells also responded to HIV/N1T infection with pronounced morphological changes, indicative of a differentiation-like process. The cells diminished in size and small neurites were observed.

Cell Line↗
PubMed1993

Preparation and characterization of whey protein hydrolysates: applications in industrial whey bioconversion processes.

A whey protein hydrolysate was prepared by incubation of reconstituted whey or a whey protein concentrate with Alcalase 0.6L. The proteolytic degradation of alpha-lactalbumin and beta-lactoglobulin initially resulted in 6-kDa and, later, 2.5-kDa degradation products, quickly followed by the appearance of multiple peptides of 1 kDa or smaller. The hydrolysate showed a steady increase in solubility and a biphasic change in foaming characteristics with decreasing peptide size. At the highest degree of hydrolysis achieved (22%), the majority of the peptides were smaller than 1 kDa and could be efficiently assimilated by the yeast Kluyveromyces marxianus growing in a defined medium.

Biotransformation↗
PubMed1993

Monoclonal antibodies to apolipoprotein AI: generation and characterization.

BALB/c mice were immunized with apolipoprotein (apo AI)--high density lipoprotein (HDL) conjugate. By polyethylene glycol-induced fusion of isolated spleen cells with the myeloma cell line P3 X63 Ag8 6.5.3, three different hybridomas were obtained and characterized. Two of them were found to secrete antibodies of the IgG2a subclass, whereas the third produced antibodies of the IgG1 type. Binding capacities to 125I-apo AI and 125I-HDL were higher than 90% in all cases. The isolated antibodies recognize independent epitopes on the apo AI molecule and bind isolated HDL and serum-HDL with different affinities.

Animals↗
PubMed1992

A trial of labor after cesarean section in patients with or without a prior vaginal delivery.

OBJECTIVE: To determine the outcome of labor in women with a previous cesarean section, with or without prior vaginal delivery. METHOD: Records were reviewed for 1065 women with a previous cesarean section at 'Virgen Macarena' Hospital who were attended for a subsequent labor. RESULTS: Chi-squared tests demonstrated that women with previous vaginal delivery (n = 346) had a significantly higher rate of vaginal delivery after a trial of labor (95.24%) than those without previous vaginal delivery (n = 719) (82.95%). All the ruptures of uterine scar (n = 4) were found in women without previous vaginal delivery. CONCLUSION: It appears that a cesarean section in a multiparous woman is not a determinant fact in her reproductive history and the risk of rupture of uterine scar did not appear to be present.

Cesarean Section↗
PubMed1992

Proliferation and morphological transformation of BALB/3T3 cells by a prolonged treatment with sodium orthovanadate.

BALB/3T3 mouse embryo cells were used to study the effect of sodium orthovanadate on cell proliferation and morphological transformation. In the presence of the chemical (0.25-1.0 micrograms/ml), the cells continued to proliferate after the cultures were confluent. However, contact-inhibited growth was resumed after removal of the chemical from the culture medium. Continued exposure of the cells to the chemical for 4 wk led to the production of numerous foci consisting of morphologically transformed cells. In contrast, as in vitro transformation assay with a 48-hr treatment protocol followed by 4 wk of incubation without the chemical produced negative results. To test the stability of the transformed foci that were produced on prolonged exposure, we isolated 20 foci with distinctly transformed characteristics from treated cultures and grew them in medium without orthovanadate. 15 isolates gradually reverted to contact-inhibited growth and five maintained the transformed phenotype through ten serial subcultures. The results show that the majority of the transformed foci from the orthovanadate-treated culture failed to maintain transformed characteristics in the absence of the chemical. However, a small fraction of the foci appeared to be altered permanently and exhibited a transformed phenotype in the absence of the chemical.

3T3 Cells↗
PubMed1991

Suicidal behavior among inner-city Hispanic adolescent females.

Suicidal behavior is disproportionately frequent among inner-city Hispanic adolescent girls. In an attempt to generate a multifactorial set of hypotheses to explain this behavior, 33 such subjects consecutively admitted for suicidal behavior and 15 demographically identical nonsuicidal subjects were assessed by means of a structured interview. Mothers of all subjects were also assessed. Attempts were nearly always impulsive and nonlethal, though often with a stated wish to die. Nearly all were overdoses, and were precipitated by conflicts with mother or boyfriend. Mothers could usually identify the precipitants. Attempters' parents were less often born in the U.S., their mothers seemed medically less healthy, and their extended families were more often supported by public assistance, and had a higher incidence of criminal and psychiatric problems. School performance was poorer among attempters, who had suffered more and earlier losses, especially of biologic fathers, with whom fewer had ongoing relationships. They more often had boyfriends, had begun sexual activity, had recently lost friends, and expressed a mistrustful stance toward friendships. Similarly, their mothers had fewer friends and more often expressed a mistrustful stance. Relationships with mothers seemed more intense, desperate, and even violent, and attempters were much more often parentified, i.e., mothering their mothers. Although both groups often assumed caretaking roles in their families, attempters were more negatively described by themselves and by their mothers. While knowledge of suicidal models was common in both groups, attempters' mothers knew of even more models than did their daughters or the nonsuicidal subjects or their mothers. Notably, more attempters' mothers had themselves made attempts. Families of most attempters were usually mobilized by the attempt. These findings permit the construction of a putative profile of risk factors that can be tested more rigorously.

Adolescent↗
PubMed1991

VP4 monotype specificities among porcine rotavirus strains of the same VP4 serotype.

The porcine rotavirus OSU strain was used to produce monoclonal antibodies (MAbs) directed against the outer capsid protein VP4. From two separate fusions, eight MAbs that inhibited hemagglutination activity of the OSU strain were selected. All MAbs immunoprecipitated both the OSU VP4 protein derived from a lysate of infected MA104 cells and the OSU VP4 protein expressed in Sf9 cells by a recombinant baculovirus. By immunoprecipitation of in vitro-translated OSU gene 4 transcripts of different length, the eight MAbs were found to be specific for the VP8 subunit of VP4. All MAbs neutralized the OSU strain but failed to neutralize human, bovine, and simian rotavirus strains. Antiserum to the expressed OSU VP4 protein was used to study the distribution of VP4 antigenicity among porcine rotaviruses. At least two distinct specificities were identified among 14 rotavirus strains that had been previously assigned to four distinct VP7 serotypes. Five groups of monotype specificities of the VP4 protein were identified by the eight anti-VP4 MAbs among 11 porcine strains that share the same VP4 serotype.

Animals↗
PubMed1991

The use of uninduced rat liver S-9 to supplement BALB/3T3 cells in the in vitro transformation assay.

Because of limited inherent capacity to metabolize chemicals to their reactive form, the BALB/3T3 transformation assay using clone A31-1-1 cells requires metabolic supplementation with rodent liver homogenate preparations (S-9). Activation by S-9 is limited, however, by its cytotoxicity to the cells, thus necessitating a reduction in treatment time from the usual 24-72 to 1-4 hr. With cyclophosphamide (CP) as a test chemical, we were able to increase the treatment time to 24 hr by using lower concentrations of cofactors and S-9 prepared from the livers of untreated rats. Statistically significant increases in transformed foci were induced in cultures treated with 50 or 100 micrograms CP/ml in the presence of 100 or 200 micrograms of uninduced rat liver S-9/ml and 76 or 380 micrograms each of NADH, NADP, NADPH, and glucose-6-phosphate per ml of incubation medium.

Animals↗
PubMed1990

Hemoglobin Birmingham and hemoglobin Galicia: two unstable beta chain variants characterized by small deletions and insertions.

Two unstable hemoglobins (Hbs) causing rather severe hemolytic anemia have been characterized. The beta chain of Hb Birmingham, found in an adult black man, is characterized by the loss of -Leu-Ala-His-Lys- at positions 141, 142, 143, and 144 and their replacement by one Gln residue. These changes are the result of a deletion of nine nucleotides, namely two base pairs (bp) of codon 141, all of codons 142 and 143, and one bp of codon 144; the remaining CAG triplet (C from codon 141 and AG from codon 144) codes for the inserted glutamine. In the beta chain of Hb Galicia from a Spanish patient, His and Val at positions 97 and 98 are replaced by one Leu residue. This is due to an ACG deletion in codons 97 and 98, which causes the removal of one His and one Val residue, while the remaining CTG triplet (C from codon 97 and TG from codon 98) codes for the inserted leucine residue. Two mechanisms, namely slipped mispairing in the presence of short repeats, and misreading by DNA polymerase due to a local distortion of the DNA helix, are considered in explaining the origin of the small deletions.

Adult↗
PubMed1990

The transcripts of zeta-crystallin, a lens protein related to the alcohol dehydrogenase family, are altered in a guinea-pig hereditary cataract.

Zeta-Crystallin, a major component of the guinea-pig lens proteins, is distantly related to the enzymes of the zinc-containing alcohol dehydrogenase family (ADH). Analysis of the structural similarities between zeta-crystallin and ADH reveals that while characteristics important in maintaining the tertiary structure of the molecule appear conserved, the amino acids binding the catalytic zinc atom are absent in zeta-crystallin. Significantly, zeta-crystallin does not have ADH activity. Previous studies showed that the zeta-crystallin protein is modified in the lens of guinea-pigs affected with an autosomal dominant hereditary cataract. We have further investigated the molecular origin of the lens defect by examining the steady-state levels of zeta-crystallin transcripts in normal and mutant eyes. Our data indicate that no normal zeta-crystallin mRNA is present in the lens of the homozygous animals; instead, a cross-hybridizing lower molecular weight mRNA is detected at significantly reduced concentrations. Heterozygous lenses exhibit both mRNA species.

Amino Acid Sequence↗