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Biomedical subjects

I Martinez

Publications and source records attributed to I Martinez.

At least 55 records · Page 3Linked to original sources
PubMed1994

Lung cancer and cigarette smoking in women: a case-control study in Barcelona (Spain).

A case-control study on lung cancer and the habit of cigarette smoking was carried out in Barcelona (Spain). Cases were 103 women newly diagnosed with primary lung cancer in 10 hospitals from the study area. Histologic confirmation was given in 101 cases, of which 53 were adenocarcinoma, 19 squamous-cell carcinoma, 9 small-cell carcinoma and 20 other types. Two controls per case were selected, matched by age, residence and hospital. Compared with the never-smokers, the odds ratios (OR), with corresponding 95% confidence intervals (CI), were 1.61 (0.4 to 6.9) for ex-smokers and 3.61 (1.6 to 8.3) for current smokers. The risk of lung cancer showed a good dose-response relationship with duration of the habit, average number of cigarettes smoked daily and cumulative cigarette consumption. The risk of lung cancer increased by 62% for each 10 pack-years. Depth of inhalation also showed a remarkable effect, independently of the intensity of the habit. Although mortality and incidence rates of lung cancer among women in Spain are lower than in other developed countries, the risk of lung cancer is that which would be expected according to the pattern of the smoking habit in Spanish women.

Adult↗
PubMed1994

Inactivation of ccmO in Synechococcus sp. Strain PCC 7942 Results in a Mutant Requiring High Levels of CO(2).

Inactivation of ccmO in Synechococcus sp. strain PCC 7942 resulted in a mutant which possesses aberrant carboxysomes and a normal inorganic carbon uptake capability but a reduced ability to photosynthetically utilize the internal inorganic carbon pool. Consequently, it exhibits low apparent photosynthetic affinity for extracellular inorganic carbon and demands high levels of CO(2) for growth.

Journal Article↗
PubMed1994

Cell targeting with retroviral vector particles containing antibody-envelope fusion proteins.

Retroviral vectors are the most efficient tool to introduce genes into vertebrate cells. However, their use is limited by the host range of the retrovirus from which they were derived. To alter the host range of the vector particle, we developed a method to substitute the receptor-binding domain of the envelope protein of a retrovirus with an antigen-binding site of an antibody. To test whether such particles are competent for infection, we established a model system using an antigen-binding site of an antibody against the hapten dinitrophenol (DNP). Retroviral vector particles containing such chimeric envelope proteins were able to bind to and infect cells that were not infectable with wild-type virus after DNP was conjugated to the cell surface. They did not infect such cells without DNP conjugation. Control experiments with chimeric envelope proteins of ecotropic murine leukemia virus (eco-MLV) and spleen necrosis virus (SNV) indicate that the pathway of virus entry of scA-env-containing virus particles was different from that of wild-type virus.

Animals↗
PubMed1993

Mapping of monoclonal antibody epitopes of the human respiratory syncytial virus p protein.

The epitopes of 10 monoclonal antibodies (MAbs) directed against the phosphoprotein (P) of human respiratory syncytial (RS) virus (Long strain) were mapped onto the protein primary structure by testing their reactivity with both protein fragments and synthetic peptides. Seven epitopes were clustered in the N-terminal end, two others were located in the central region, and one epitope was mapped in the C-terminal end of the P molecule. The location of epitopes in the P protein sequence correlated with other properties, such as antigen binding competition and immunofluorescence staining of RS virus-infected cells. The antibodies that recognized epitopes of the N-terminal end revealed the presence of cytoplasmic inclusions while others gave mainly a diffuse cytoplasmic staining. Thus, accessibility of certain P protein epitopes seems influenced by the incorporation of this molecule to the inclusions of RS virus-infected cells.

Amino Acid Sequence↗
PubMed1993

Downstream insertion of the adenovirus tripartite leader sequence enhances expression in universal eukaryotic vectors.

A series of universal eukaryotic gene expression vectors was constructed. All vectors contain a viral promoter and enhancer, a polylinker for insertion of the gene of interest and a polyadenylation sequence. To enhance translation, we inserted the tripartite leader sequence of an adenovirus downstream of the promoter. Using the chloramphenicol acetyl transferase (cat) gene as a marker, we show that the strength of various promoters/enhancers in different cell lines differed by two orders of magnitude. The presence of the tripartite leader increased the efficiency of gene expression up to 18-fold. The level of increase is promoter specific and is most likely influenced by additional sequences flanking the tripartite leader sequence.

3T3 Cells↗
PubMed1993

Calcium mass transfer in CAPD: the role of convective transport.

One hundred and fifty calcium (Ca) balance studies were performed in 50 patients treated with CAPD using dialysate with a 1.75 mmol/l (7 mg/dl) Ca content, in order to calculate the peritoneal balance of Ca by measuring the Ca in all the effluent for a 24-h period, and looking at the influence of serum ionized Ca and the ultrafiltration rate in the calcium balance. Of the 150 balance studies, 77 were made using four exchanges of dialysate per day and 73 using three exchanges per day. The serum ionized Ca was 1.17 +/- 0.09 mmol/l, the ultrafiltration 844 +/- 723 ml/day and the peritoneal Ca transfer 39 +/- 46 m/day. The net Ca abortion with four exchanges was less than that with three exchanges per day. There was a strong negative correlation between the peritoneal Ca absorption and the ultrafiltration (r = -0.7, P < 0.00001) and with the ionized Ca (r = -0.49, P < 0.0001). Thirty-three peritoneal balance studies showed a negative Ca balance and in all 33 cases ultrafiltration was greater than 350 ml/day. We conclude that the peritoneal balance of Ca depends not only on the serum ionized Ca, but also on ultrafiltration. The lesser Ca gain observed with four dialysis exchanges per day is due to greater ultrafiltration rates present in this setting.

Calcium↗
PubMed1992

Two-dimensional electrophoretic analyses of cod (Gadus morhua, L.) whole muscle proteins, water-soluble fraction and surimi. Effect of the addition of CaCl2 and MgCl2 during the washing procedure.

Samples from pre- and post-rigor cod mince, surimi (a concentrate of fish myofibrillar proteins obtained after washing and dewatering the fish mince) and water from the first wash in the surimi manufacture, processed with and without the addition of 7.5 mM CaCl2 and 15 mM MgCl2, were analyzed by two-dimensional electrophoresis. The results showed that the main myofibrillar proteins, including myosin, actin and tropomyosin, remained in the surimi. Several other proteins were selectively removed during the washing procedure. Some additional major spots were detected in the two-dimensional gels containing samples of the wash water and surimi processed with the addition of Ca2+ and Mg2+ salts. These spots were either absent or present in minor amounts in the samples of post-rigor cod mince, wash water and surimi processed without Ca2+ and Mg2+ salts and in all the pre-rigor samples. This induced us to suggest that the new additional spots may constitute fragments of proteins originated by increased proteolytic activity during the surimi manufacture upon the addition of the Ca2+ and Mg2+ salts. Two-dimensional electrophoresis has proved to be a valuable tool to quickly and easily assess the effect of different processing conditions on the protein content of the products.

Animals↗
PubMed1991

Comparison of myosin isoenzymes present in skeletal and cardiac muscles of the Arctic charr Salvelinus alpinus (L.). Sequential expression of different myosin heavy chains during development of the fast white skeletal muscle.

The expression of myosin isoforms and their subunit composition in the white skeletal body musculature of Arctic charr (Salvelinus alpinus) of different ages (from 77-day embryos until about 5 years old) was studied at the protein level by means of electrophoretic techniques. Myosin from the white muscle displayed three types of light chain during all the developmental stages examined: two myosin light chains type 1 (LC1F) differing in both apparent molecular mass and pI, one myosin light chain type 2 (LC2F) and one myosin light chain type 3 (LC3F). The fastest-migrating form of LC1F seemed to be predominant during the embryonic and eleutheroembryonic periods. The slowest-migrating form of LC1F was predominant in the 5-year-old fish. Between 1 year and 4 years, both types of LC1F were present in similar amounts. Cardiac as well as red muscle myosin from 3-year-old fish had two types of light chain. The myosin light chains from atria and ventriculi were indistinguishable by two-dimensional electrophoresis, but were different from the myosin light chains from red muscle. Neither the light chains from cardiac nor red muscle were coexpressed with the myosin light chains of white muscle at any of the developmental stages examined. Two myosin heavy chain bands were resolved by SDS/glycerol/polyacrylamide gel electrophoresis of the extract from embryos. One of the bands was present in minor amounts. The other, and most abundant, band comigrated with the only band found in the extracts of white muscle myosin from older fish. One-dimensional Staphylococcus aureus V8 protease peptide mapping of these bands revealed some differences during development of the white muscle tentatively interpreted as follows. The myosin heavy chain band present in minor amounts in the embryos may represent an early embryonic form that is replaced by a late embryonic or foetal form in the eleutheroembryos. The foetal myosin heavy chain appears to be present until the resorption of the yolk sack and beginning of the free-swimming stage. A new form of myosin heavy chain, termed neonatal and probably expressed around hatching, is present until about 1 year of age.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗
PubMed1991

Testing the safety of non-disconnect disposable Y sets for peritoneal dialysis.

In order to test the efficacy of the Del Clamp as a contamination barrier, the following protocol was carried out. Sixty bags of dialysate (1.5 L, 1.5% Dextrose) were connected to matching disposable Y sets and 100 mL of dialysate allowed to flow into each drain bag, after which the clamps were closed. The bags were arranged in groups of 10 and each group was inoculated with 1 mL of a standard suspension of S. aureus, S. epidermidis, E. coli, E. faecalis, P. aeruginosa and C. albicans, respectively. 3 bags were inoculated and left with the clamp open as controls. After 6 hr, incubation at 37 degrees C, 20 mL duplicate samples from each drain bag were centrifugated and processed for anaerobic and aerobic culture. None of the specimens taken from the sets grew bacteria or fungi. All the drain bags of the control sets grew the inoculated organism. We conclude that the Del Clamp makes CAPD safer by working as an effective contamination barrier and eliminating a potential for combination during the dialysis exchange.

Bacteria↗
PubMed1990

Intraspecific myosin light chain polymorphism in the white muscle of herring (Clupea harengus harengus, L.).

The myosin contained in white and red muscles of herring (Clupea harengus harengus) was purified, and its subunit composition analyzed by electrophoretic techniques. The only myosin isoform present in red muscles was made up of one type of heavy chain and two types of light chain. The native myosin from white muscles migrated as one wide band. Analysis of the extracts by SDS/glycerol/PAGE from white muscles revealed one main type of heavy chain. Light chains were identified by SDS-PAGE analysis of electrophoretically purified myosin, and two-dimensional electrophoresis of the extracts demonstrated differences in the light chain composition of white and red muscles. Using this methodology, light chain polymorphism was detected in white muscles among members of the same species.

Animals↗
PubMed1990

Myosin isoforms in red and white muscles of some marine teleost fishes.

The myosin content from red and white muscles of three marine fish species, saithe (Pollachius virens. L.), haddock (Melanogrammus aeglefinus, L.), both members of the family Gadidae, and capeline (Mallotus villosus, M.) of the family Osmeridae, was analyzed electrophoretically. Analysis of the native myosin by electrophoresis under non-dissociating conditions revealed two isoforms in red muscles, and three or four in white muscles. The white muscles of the two closely related species had a similar pattern of isoforms. Myosin from the slow red muscles had two types of light chain, LC1S and LC2S, and myosin from the fast white muscles three, LC1F, LC2F, and LC3F. The pattern of light chains in both types of muscles was species-dependent. All the light chains from fish myosins were more acidic than those of the rat diaphragm used as standard. One main type of heavy chain was detected in each kind of muscle. In white muscles of saithe there was an extra band, present in minor amounts. The heavy chains from white muscle myosin had lower electrophoretic mobilities than those from red muscle, and the mobilities of all of them were intermediate between those of the heavy chains type IIa and I of rat diaphragm myosin. In our opinion, there are probably more isomyosins in fish muscles than those detected in the present work and their presence is obscured by comigration with the main types.

Animals↗
PubMed1990

Electrophoretic study of myosin isoforms in white muscles of some teleost fishes.

1. White skeletal muscle myosin of four marine teleost fish species (cod, blue whiting, Norway haddock, and spotted wolf-fish) was analyzed by native, SDS-PAGE, and 2-dimensional electrophoresis. 2. Four types of native myosin were present in cod, blue whiting and Norway haddock. The second fastest migrating form was predominant. 3. Myosin from spotted wolf-fish also resolved into four forms. The fastest migrating form was hardly noticeable. The other three were present in apparently similar amounts. 4. In the myosin from each species there were three types of light chains. The pattern of light chains was species specific. 5. Apparently, there was only one type of heavy chain in myosin from cod, Norway haddock and spotted wolf-fish. One preparation of cod showed an extra band of higher electrophoretic mobility than the main band. In blue whiting we found two bands present in approximately equal amounts.

Animals↗
PubMed1989

Comparative study of the behavioral changes evoked by d-amphetamine and apomorphine in adult cats. Dose-response relationship.

The behavioral effects of d-amphetamine and apomorphine administration were studied in 17 adult cats. The doses of amphetamine administered were 0.1, 0.5, 1.0 and 5.0 mg/kg; those of apomorphine, 0.1, 0.5, 1.0 and 2.0 mg/kg. These two drugs evoked in the same animal marked differences in behavioral responses. Amphetamine induced a dose-dependent hypomotility, which was marked with the higher doses. In addition, rhythmic, bilateral slow movements of the head as a mode of stereotypy, indifference to the environment and dose-dependent increase in respiratory rate. Apomorphine elicited limb flicking, dose-dependent hypermotility and increase in olfactory behavior, the last two reactions with stereotypy characteristics. The animals appeared as if being scared, hyperreacting to sudden stimuli and showing total indifference to the surrounding environment. There were marked differences in behavioral responses evoked by these two agonists of the catecholaminergic system. These data do not conform with the behavioral reactions reported in the rat by other investigators. The disagreement with other communications is probably due to differences in reactivity of the species employed. The processes involved in the diversity of the behavioral responses of the cat to the administration of amphetamine and apomorphine have not been delucidated.

Animals↗
PubMed1989

Pulmonary phospholipids in amniotic fluid of pathologic pregnancies: relationship with clinical status of the newborn.

We evaluated phospholipids, C-peptide and cortisol levels in amniotic fluid of 203 pathologic pregnancies (63, class A, B and C diabetics; 11 class D, F and H diabetics; 44 preclampsia and 85 Rh-isoimmunization); the control group was 82 normal pregnant women. There was an acceleration of fetal pulmonary maturation in women with preclampsia and severe Rh-isoimmunization in class D, F and H diabetics (at 34 weeks gestation the incidence of mature surfactant (lecithin/sphingomyelin greater than or equal to 2.7 and presence of phosphatidyl-glycerol) in these groups was 30%, 50% and 100%, respectively, while it was zero in the control group). At 37 and 38 weeks only 44.4% of the class A, B and C diabetics had mature surfactant and there was a significant difference with respect to the control group (x2 = 4.9; p less than 0.05); C-peptide levels in these diabetics (class A, B and C) were higher than in controls (p less than 0.001); in pregnant women with accelerated fetal lung maturation they were lower. We demonstrated a close relationship between fetal pulmonary maturity and the type of surfactant in amniotic fluid, which was independent of gestational age.

Amniotic Fluid↗
PubMed1987

The formation of amino acid precursors in the reaction of atomic carbon with water and ammonia at 77 K.

When atomic carbon is condensed on a surface at 77 K containing ammonia and water, glycine, N-methylglycine, alanine, beta-alanine, aspartic acid and serine are generated. It is postulated that these reactions may mimic those which occur when an extraterrestrial carbon atom condenses on a frozen surface coated with water and ammonia and may provide a route to extraterrestrial amino acids. Experiments designed to elucidate the mechanisms of amino acid formation under these conditions have been carried out.

Amino Acids↗