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Biomedical subjects

R Martínez

Publications and source records attributed to R Martínez.

At least 19 recordsLinked to original sources
PubMed1995

Transgenic rabbits as bioreactors for the production of human growth hormone.

Gene farming is one of the most promising areas in modern biotechnology. To assay the potential usefulness of transgenic rabbits as bioreactors, one call embryos were microinjected with a chimeric gene comprising 5' sequences from mouse whey acidic protein gene (mWAP) linked to the human growth hormone (hGH) gene. Transgenic animals were obtained and the presence of the foreign protein was detected in the milk and serum of these animals at levels of up to 50 micrograms ml-1 and 0.6 ng ml-1, respectively. Founder transgenics were able to transmit the microinjected gene to the first filial generation in a Mendelian fashion. These results showed that transgenic rabbits could constitute a suitable system for the rapid production of recombinant proteins in the milk of lactating females.

Animals↗
PubMed1995

Differential constitutive expression of interferon genes in early mouse embryos.

Recent evidence suggests that several processes during mammalian embryogenesis may be regulated by IFNs or IFN-like molecules. With the use of MAPPing, the simultaneous presence of transcripts homologous to IFN-alpha, IFN-beta, IRF-1, and IRF-2 was examined in mouse embryos and in embryonal carcinoma (EC) P19 cells, which are equivalent to epiblast cells of the early postimplantation blastocysts. Transcripts for IFN-alpha, but not for IFN-beta, were detected as maternal transcripts in the ovulated oocyte and persisted over early embryogenesis. IRF-1 transcripts appeared only after the first cell cleavage in the two-cell stage embryo. IRF-2 transcripts were analyzed only in EC P19 cells and were found in both undifferentiated (D-) and differentiated (D+) cells. The IFN-alpha transcripts present in (D-) P19 cells were cloned and the partial cDNA sequences determined. Mu IFN-alpha A and a new Mu IFN-alpha species (Mu IFN-alpha 12) were isolated from (D-) P19 cells. The presence of constitutive IFN-alpha transcripts in early mouse embryos suggests a role for these molecules during embryogenesis.

Animals↗
PubMed1995

Protective effect of estrogens and catecholestrogens against peroxidative membrane damage in vitro.

The antioxidant effects of natural estrogens (estrone, E1; 17 beta-estradiol), synthetic estrogens (17 alpha-ethynylestradiol, EE2; mestranol, MES; diethylstilbestrol, DES) and catecholestrogens (2-hydroxyestradiol; 4-hydroxyestradiol, 4-OHE2) on lipid peroxidation induced by different means in rat liver microsomes were investigated. The extent of lipid peroxidation was determined by measuring thiobarbituric acid reactive substances. Prooxidants included Fe3+/ADP/reduced NADPH, Fe2+/ascorbate, tert-butyl hydroperoxide (t-BOOH) and 2,2'-azobis(2-amidinopropane) (AAPH). Estrogens and catecholestrogens decreased lipid peroxidation in all four systems tested. In the iron/ascorbate model it was shown that (i) 4-OHE2 and DES had analogous patterns of inhibition, irrespective of the presence of NADPH or the functional integrity of the microsomes, and (ii) the antioxidant activities of E1, EE2 and MES were dependent on the assay conditions with the activity being markedly higher when estrogen metabolism was favored. When peroxidation was initiated by the peroxyl radical generator AAPH, the inhibitory effects observed were least pronounced. Our data also showed that, in each of the systems, all inhibitors displayed the same order of inhibitory potency with DES and catecholestrogens being the most potent antioxidants under all experimental conditions used. The present results confirm earlier findings and point toward a link between estrogen metabolism and estrogen antioxidant activity. The data also indicate that estrogens and catecholestrogens interact with the peroxidative process at different levels with their interactions with iron or the metal-derived species being the most important modes of inhibition.

Animals↗
PubMed1995

Conformational analysis and biological activity of leptocarpin and leptocarpin acetate.

This paper deals with the conformational study in solution of leptocarpin, a germacranolide with the heliangolide structure isolated from Leptocarpha rivularis D.C. The results obtained agree with the single crystal X-ray diffraction studies. Leptocarpin and leptocarpin acetate show 50% inhibition of [35S]-methionine uptake without affecting the (methyl-3H)thymidine and (5,6-3H)uridine incorporation, when assayed in HeLa cells.

4-Butyrolactone↗
PubMed1995

C-terminal phosphorylation of human respiratory syncytial virus P protein occurs mainly at serine residue 232.

To determine which human respiratory syncytial virus (HRSV) P protein serine residues are modified by cellular protein kinase(s), several mutated versions of P protein were expressed in the absence of other viral proteins. Mutations at serines 232 or 232 and 237 drastically reduced the extent of phosphorylation P protein in vivo. Serine 232 is the main site of modification and is also essential for in vitro phosphorylation by casein kinase II. Additional in vivo phosphorylation was also detected in the region containing serines 116, 117 and 119.

Amino Acid Sequence↗
PubMed1995

Increase in cardiac output and PEEP as mechanism of pulmonary optimization.

The influence of cardiac output (CO) and PEEP on pulmonary shunt (Qs/Qt) has been the subjects of considerable investigation but findings are controversial. The role of CO and PEEP on 19 isolated rabbit lung preparations perfused with hypoxic mixture (6% CO2, 10% O2, and 84% N2), which resulted in a constant oxygen venous pressure (64 +/- 5.6 mmHg) has been studied. The first group of 11 preparations were used to study the influence of CO modifications with room air ventilation on the Qs/Qt when the CO rises in 48%; in the second group simultaneous modifications in CO and PEEP (0.5 and 10 cm H2O) were performed. A positive correlation (p < 0.01) in Qs/Qt (0.048 +/- 0.04 to 0.12933 +/- 0.09) was found when the CO increased in the first experimental group, the fluid filtration rate (FFR) also increased and the pulmonary vascular resistance (PVR) remained stable. In the second group an increase of 5 and 10 cm H2O of PEEP at constant CO reduced the Qs/Qt (0.0361 +/- 0.02 to 0.0184 +/- 0.006) while it increased the arterio-venous oxygen difference, PVR and FFR. During high CO conditions increase of 5 and 10 cm H2O of PEEP reduced the Qs/Qt (0.099 +/- 0.03 to 0.027 +/- 0.02) and FFR. These data suggest that when the Qs/Qt is increased, the use of PEEP can compensate the ventilation/perfusion alterations and restore pulmonary gas exchange.

Animals↗
PubMed1995

[Medical evaluation of the climacteric patient].

A pilot program with primary care physicians was established in Clinica Cuauhtémoc y Famosa, focused to evaluate women older than 35 years with climateric symptoms. This program included a survey, a complete gynecological examination with Pap smears, ultrasound pelvic examination and mamography. Also, blood samples were collected for cholesterol, tryglycerides, calcium, phosphorus and alkaline phosphatase. An ECG, bone densitometry of the radius and X-rays of the vertebral column were obtained. This group was formed by 69 women with an age media of 50 years (SD 7.6 years, median 49 years). The survey disclosed that 34/65 women had been hysterectomized, and only 34/64 had received antitetanic immunization in the last 10 years. A preexistent chronic disease occurred in 36/59 women, these were diabetes mellitus, arterial hypertension or degenerative osteoarthritis. Alcohol consumption was recorded in 5/66 women and tabac consumption in 9/66 women, and 32/68 women accepted to be sedentary. Laboratory examinations disclosed hypercholesterolemia in 19/66 women and hypertryglyceridemia in 8/64 women. Osteopenia was detected in 33/60 women. This findings support a systematic plan to provide medical assistance for women in this age, specially if previous epidemiologycal studies have disclosed that coronary disease is the main cause of death for women older than 50 years in this region, that also belongs to the area of highest incidence of diabetes.

Alcohol Drinking↗
PubMed1993

[The usefulness of the bcr/abl rearrangement in the diagnosis and evolution of chronic myeloid leukemia].

BACKGROUND: The rearrangement of the bcr/abl gene constitutes the molecular substrate of the Philadelphia chromosome (Ph'). The aim of this study was to analyze the usefulness of bcr/abl rearrangement in the diagnosis and evolution of chronic myeloid leukemia (CML). METHODS: The rearrangement of the bcr/abl gene was studied in 81 cases of which 34 corresponded to patients with CML (29 Ph' positive chromosome, 2 Ph' negative chromosome and 3 without karyotype), 2 patients with Ph' positive acute lymphoblastic leukemia, 15 patients with chronic myeloproliferative syndromes different from CML and 30 controls. Of the patients with CML, 6 were reevaluated when a blastic crisis was developed, 2 after receiving interferon treatment and 1 following allogeneic bone marrow transplantation. The technique used was that of Southern blotting using the restriction enzymes Bgl II and BamHI and the transprobe. RESULTS: Rearrangement of the bcr/abl gene was observed in all the patients with CML except in one with Ph' negative chromosome. In the remaining cases bcr/abl rearrangement was not observed. CONCLUSIONS: The Southern blotting technique for the study of the bcr/abl gene rearrangement is a sensitive and specific method in the diagnosis of chronic myeloid leukemia constituting a valid alternative to chromosomic study when this cannot be carried out or is not conclusive. It may also be used for the control of treatment in chronic myeloid leukemia.

Adult↗
PubMed1993

[Effects of juvenile hormone on vitellogenesis in Spilostethus pandurus (Hemiptera: Heteroptera)].

The effects of juvenile hormone (JH) on the control of vitellogenin appearance in the haemolymph of Spilostethus pandurus newly emerged females have been studied as well as their intake by developing oocytes. SDS-PAGE electrophoresis has been used as an analytical method for protein studies. JH induced early detection of vitellogenins in the haemolymph of treated insects and their accelerated incorporation by undeveloped ovaries. The results suggest that JH plays an essential role as a gonadotrophic agent, just as it has been described for other insect species.

Animals↗
PubMed1993

[Ileoanal anastomosis with a J reservoir. The evolution of the technic and the results].

Beginning 1982, our group has been performing the technique of ileal pouch-anal anastomosis, changing the procedure for achieving better functional results, less morbidity and making it easier. Fifty patients operated on for ulcerative colitis and "polyposis coli" were grouped as follows: Group I (28): proctocolectomy, mucosectomy, handsewn anastomosis and temporary ileostomy; Group II (13): proctocolectomy without mucosectomy, leaving a rectal stump up to just the level of the puborectalis, instrumental anastomosis and no-ileostomy; Group III (9): Same as Group II but with the implant of an endoluminal prosthesis to defunction the pouch. From our results it is concluded that, provided an adequate selection of patients is done, the best technique is the one performed in Group III due to its simplicity, no morbidity related to the ileostomy, no risk of fistula and probably better functional results than in Group II.

Adenomatous Polyposis Coli↗
PubMed1993

[Listeria monocytogenes infection in HIV patients: 2 new cases].

Two new cases of infection due to Listeria monocytogenes in two females with HIV are discussed, one of them with full blown AIDS and the other pregnant and without knowledge of her seropositivity until that moment. Its clinical manifestation as a meningeal manifestation and bacteremia, coincide with the few cases described until now; different hypothesis invoked until now are reviewed to justify this infrequent association HIV-Listeria.

AIDS-Related Opportunistic Infections↗
PubMed1992

Neurosurgical experience with tumours of the pineal region at Clinica Puerta de Hierro.

The clinicopathological experience with 50 cases of pineal region tumours at Clinica Puerta de Hierro is presented. In this series, 88% of the patients were evaluated by CT-scan. Pineal region tumours make up approximately 0.7% of the intracranial expansive processes in the Spanish population. The largest group of lesions appearing in this localization is that of the germinomas (38%), followed by nontumoural lesions (20%) and tumours generally considered to be of the vicinity, such as meningiomas, gliomas and metastases (18%), tumours of the pineal parenchyma (14%), and non-germinoma germinal tumours (10%). In our series, in addition to an intracranial hypertension syndrome, an ophthalmological and, to a minor degree, an endocrinological syndrome predominate in germ-cell tumours, with a cerebellar syndrome appearing in gliomas of the pineal region. All the patients in the series diagnosed as having a germinoma and treated by irradiation are alive, and free of disease, after follow-up ranging from 2 to 20 years (mean: 8 years). The experience obtained with the present series supports the opinion that, in radiosensitive tumours, surgical resection adds no therapeutic benefit to treatment with radiotherapy alone. We suggest that when dealing with a tumour of the pineal region, CT-scan and clinical assessment now permit an initial selection of patients susceptible to surgery as a first therapeutic option, indicating those patients who, because they are considered to have either a "probable germinoma" or a "tumour of uncertain diagnosis", should undergo stereotaxic biopsy or trial radiotherapy and, only when this has proved a failure, should be subjected to open surgery.

Adolescent↗