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Biomedical subjects

M Marin

Publications and source records attributed to M Marin.

72 records · Page 4Linked to original sources
PubMed1991

[The Pordenone study on the precursors of atherosclosis in childhood. A 10-year follow-up. Cigarette smoking].

We have studied smoking habit in the sample enrolled in the ten year follow-up of the "Pordenone Study on the Precursors of Atherosclerosis in Childhood". The response rate at ten year follow-up was very high (about 90%). Prevalence of smoking is 45.1% among males and 25.6% among females. Males and females aged 23 present a prevalence of smokers higher than the other groups while the group aged 26 smoke less. Males began to smoke at 16.4 years, females at 16.7. Mean daily consumption is 12.6 cigarettes among males, and 5.0 among females. Juvenile experimentation with cigarettes and juvenile smoking habit are strong predictors to smoke ten years later; while parental smoking behaviour is not so influential. Therefore we conclude that smoking habit acquired in youngs has a high probability to be maintained in adults, remarking the importance of planning a preventive intervention as early as possible.

Adolescent↗
PubMed1991

Borreliosis risk after tick bite in north-eastern Italy.

Lyme Borreliosis is an infectious disease caused by the Borrelia burgdorferi spirochete transmitted to man by a tick bite. The aim of this study was to assess the predictive value of tick bites for the diagnosis of Borreliosis in a sample of 266 subjects residing in an endemic area of north-eastern Italy. In the serological diagnosis of Borreliosis, positive and negative predictive values of tick bites were found to be 24% and 88% respectively.

Adolescent↗
PubMed1987

Megakaryocytic development in liquid cultures of cryopreserved leukocyte stem cell concentrates from chronic myelogenous leukemia patients.

The proliferation and differentiation of human megakaryocytes in liquid culture has been obtained using cryopreserved light-density blood cell concentrates from chronic myelogenous leukemia (CML) patients. A large number of megakaryocytes, representing 20%-60% of total cells cultured, developed after 12-14 days in liquid cultures supplemented with human plasma, while fetal calf serum supported the development of cells of the megakaryocytic lineage poorly. Ploidy studies showed the presence of 8N and 16N cells in human plasma-supplemented cultures while very few cells with DNA content greater than 4N were found in those supplemented with fetal calf serum. Using the FACS IV cytofluorometer, 1-2 X 10(6) megakaryocytes/h were sorted after immunolabeling of the human plasma-cultured cells with a monoclonal antibody reacting against the platelet glycoprotein complex IIb-IIIa. Thus, cryopreserved CML blood stem cell concentrates seem to offer a reproducible source of human megakaryocytes that retain their capacity to proliferate and differentiate in liquid cultures. These megakaryocytes can be used for the study of platelet glycoprotein biosynthesis as well as the regulation of megakaryocytopoiesis.

Blood Specimen Collection↗
PubMed1985

In vitro transcription initiation from three different Escherichia coli promoters. Effect of supercoiling.

Transcription initiation from beta-lactamase, tetracycline resistance and RNA 1 promoters, present in plasmid pAT153, were studied employing the abortive initiation technique. Assays appear to be promoter-specific with supercoiled and linear templates. Supercoiling enhances the isomerization rate constant of the open RNA-polymerase--promoter complex formation. Results agree with the in vivo behaviour of the corresponding promoters, and allow us to propose a hypothesis about the effect of supercoiling on transcription initiation.

DNA, Superhelical↗
PubMed1985

[Hysteroplasty for hemi-uterus and divided uterus. Apropos of 45 cases].

The authors present a series of 45 plastic operations for bicornuate uterus. Three women were operated on for functional symptoms, eight for sterility of which seven were primary, and thirty four for infertility. They are sorry that three women were lost to follow up. They used the Bret-Palmer technique with modifications that they themselves describe. They justify this choice as against other techniques of metroplasty. The anatomical results are, in the main, good when controlled by hysterosalpingography 3 to 6 months after the operation. The functional results, by which is meant the pregnancies that have been obtained, are medium as far as sterility is concerned. Four out of the eight women who were operated on became pregnant. But they are very good in cases of infertility, because thirty out of the thirty four cases that were operated on had one or two pregnancies. The authors justify their indications for metroplasty after a first spontaneous abortion by the good results they have had, and because bicornuate uteri give rise to many obstetrical complications. Furthermore in unoperated cases there is often difficulty in attempting a new pregnancy, and quite often spontaneous late abortions or premature labours. In certain cases they carried out the operation after first spontaneous abortions, but they are more conservative in operating in cases of primary sterility. The authors do not think it is necessary always to carry out a cerclage procedure nor a caesarean operation automatically in cases that have become pregnant after metroplasty.

Abortion, Spontaneous↗
PubMed1984

Promoter recognition and transcription initiation in E. coli.

Analysis of stability maps of sequences harbouring E. coli RNA polymerase promoters shows a characteristic splitting in homostable domains, despite the heterogeneity of the sequences. Correlation of stability maps with results from static approaches giving the contact points of the enzyme on promoters and functional studies employing abortive initiation assay allow us to propose a general mechanism for recognition of promoters and transcription start.

Base Composition↗
PubMed1983

High performance liquid chromatographic analysis of molecular species of phosphatidylcholine--development of quantitative assay and its application to human bile.

In this paper we propose a novel, rapid and simple high-performance liquid chromatographic (HPLC) method for the identification and quantitation of individual phosphatidylcholine (PC) molecular species from natural mixtures. To overcome difficulties deriving from the lack of adequate standards and from the variability of the responses to UV spectrophotometric detectors currently used in HPLC analysis, we first fractionated and quantitated the major molecular species of a commercial egg PC by means of a preparative column. The identification of PC molecular species was confirmed by gas-liquid chromatographic analysis of fatty acids. We employed the fractions recovered from preparative HPLC to determine the detector calibration factors of the individual molecular species separated using an analytical, high-speed, reversed-phase HPLC column. The proposed method seems to be adequate for the analysis of PC from many biological sources. Its application to the analysis of human hepatic and gallbladder biliary PC is shown.

Bile↗
PubMed1982

Regeneration of rat tracheal epithelium: changes in gap junctions during specific phases of the cell cycle.

Uninjured mitotically inactive tracheal epithelium has virtually no gap junctions. When the epithelium is stimulated to proliferate synchronously through a single wave of DNA synthesis and cell division, study of thin sections and freeze-fracture replicas by conventional transmission electron microscopy reveals that gap junctions are formed by the end of the DNA synthetic (S) phase. During the period of mitosis (M), the gap junctions disappear and are not again observed as the superficial cells undergo mucous and ciliary differentiation and normal pseudostratified architecture is restored. If the regenerative cells are continuously stimulated so they go through at least one additional S phase, gap junctions begin to reappear in G1 and reach peak numbers at the end of the second S phase. The correlation of the appearance of gap junctions in regenerating tracheal epithelium with a specific phase of the cell cycle and the absence of these junctions in cells in other phases of the cycle and in the differentiated progeny cells suggests that this surface feature plays a role in control of mitotic activity.

Animals↗
PubMed1981

[Analysis of the stability and local cooperativity of DNA : elements permitting the recognition of promoters by DNA-dependent RNA polymerase].

Analysis of the local stability of promoters processed by E. Coli RNA polymerase shows that they bear a characteristic stability profile: two segments of low stability are located around --35 and --8 bases ahead of the transcription start and are generally bordered by more stable segments. This key profile may act as a recognition signal for both attracting and positioning the RNA polymerase in the promoter site.

Base Sequence↗
PubMedDate not supplied

Effects of omeprazole on ethanol metabolism: an in vitro and in vivo rat and human study.

Since some H2-receptor antagonists, like cimetidine or ranitidine, affect ethanol metabolism by interference with gastric and/or hepatic alcohol dehydrogenase (ADH) it was investigated whether omeprazole has a similar effect and its effects were compared with those of cimetidine, an inhibitor of gastric ADH. The first-pass metabolism (FPM), quantified by measuring the difference between areas under the curve (AUC) of ethanol blood concentrations after oral intake or intravenous administration of the same amount (0.3 g kg-1 b.w.) of ethanol (EtOH), was studied before and after 1 week of omeprazole (20 mg daily) or cimetidine (800 mg daily) administration in 10 normal male volunteers. ADH activity was determined in gastric mucosal samples, collected during endoscopy, before and after 1 month of omeprazole treatment. The effect of the drugs on gastric and hepatic ADHs was studied in vitro in both rat and man. No significant effect of omeprazole was found on AUCs of the blood EtOH concentrations. The ADH activity in antral mucosa before and after omeprazole therapy did not show significant differences. In vitro, omeprazole reduced the activity of the low Km gastric ADH with a Ki of 5.6 mM in rat and the hepatic ADH activity with a Ki of 2.4 mM in man, whereas the drug did not show any effect on hepatic ADH in rat and gastric ADH in man. On the contrary, cimetidine increased the AUCs of EtOH blood concentrations after both gastric and intravenous route and, in the in vitro assay, inhibited gastric and hepatic ADH in both man and rat. These results indicate that omeprazole does not affect EtOH metabolism in man and seems to be safer than cimetidine in subjects unable to reduce ethanol intake during the therapy for peptic ulcer or other hypersecretory conditions.

Administration, Oral↗
PubMedDate not supplied

Improvement of porphyrin cellular delivery and activity by conjugation to a carrier peptide.

The chemical nuclease metalloporphyrin (manganese(III) porphyrin) can cleave DNA irreversibly and can thus constitute a potential antitumor drug. However, these molecules show low permeability to cell surface membranes. We report here the conjugation of an amphipathic carrier peptide to improve considerably its cellular delivery. The metalloporphyrin-peptide conjugate can be internalized by cells within only 5 min of incubation with a yield as high as 80%. Furthermore, the metalloporphyrin-peptide conjugate is able to cleave in vitro high or low molecular weight DNA to the same extend as metalloporphyrin alone without affecting the sequence-specific cleaving activity of the porphyrin. The conjugate is 100-fold more efficient at inducing tumor cells death than the free metalloporphyrin via a mechanism involving genomic DNA cleavage. The results are promising for further therapeutic applications with antitumor drugs such as metalloporphyrin, and also with other existing drugs by using a carrier peptide system in order to improve the cellular uptake of such molecules.

Amino Acid Sequence↗
PubMedDate not supplied

[Meningococcal meningitis in Spain (1878-1987). VI. Evolution of the proteic subtypes within the serotypes 2 and 15 of Neisseria meningitidis during the epidemic wave].

We have serotyped 620 strains of Neisseria meningitidis, isolated from patients between 1978-1987. These strains, belonging to serotypes 2 and 15, were the most prevalent ones detected during the last epidemic outbreak in Spain. These strains were analyzed by means of polyacrylamide gel electro-phoresis and monoclonal antibody coagglutination, to differentiate subtypes into type 15 and type 2 complex (2a, 2b and 2c types). The proportion of type 2b strains is quite high in group B, and the proportion of subtypes P1.15 and P1.16 is very similar in the same serogroup. We compared the results with those obtained in other countries in our geographical area.

Bacterial Proteins↗
PubMedDate not supplied

[Cases of serous otitis admitted to the ENT Department of the V. Babeş Hospital over the last 7 years].

A total number of 283 patients with serious otitis were admitted during the latter 7 years. In more than 98% of cases the auditory function was integrally recovered to values prior to the disease following the treatment of tubal dysfunction and serious otitis. In case of complete irreversible block at the level of the tributary ototubal lymph nodes perforation of the ear drum and otomastoid superinfections may occur. Stress is laid on the importance of a correct diagnosis and timely intervention before severe alteration of the auditory function.

Drainage↗