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Biomedical subjects

L Cañedo

Publications and source records attributed to L Cañedo.

14 recordsLinked to original sources

Magnetic field exposure during gestation: pineal and cerebral cortex serotonin in the rat.

Extremely low frequency (ELF) magnetic fields seem to have a reproducible influence on cells in transitional states, such as cells during the embryonic and early postnatal periods. Intense and continuous serotonergic synaptic growth is present during the first 2 weeks of postnatal development, paralleled by 5-HT content in the brain, so, the effect of ELF on 5-HT content in the cerebral cortex and pineal gland was determined in growing rats exposed during pregnancy, and in normal controls. The results showed a significant 5-HT increase at birth, 15 and 21 days, in the cerebral cortex. No differences were found in the pineal gland. These short MF exposures had a long term effect on cerebral cortex 5-HT, possibly starting since the fetal period. The relevance of the present findings are discussed as related to the serotonin trophic role on the brain cortex.

Age Factors↗

Two different pathways are involved in the beta-oxidation of n-alkanoic and n-phenylalkanoic acids in Pseudomonas putida U: genetic studies and biotechnological applications.

In Pseudomonas putida U, the degradation of n-alkanoic and n-phenylalkanoic acids is carried out by two sets of beta-oxidation enzymes (betaI and betaII). Whereas the first one (called betaI) is constitutive and catalyses the degradation of n-alkanoic and n-phenylalkanoic acids very efficiently, the other one (betaII), which is only expressed when some of the genes encoding betaI enzymes are mutated, catabolizes n-phenylalkanoates (n > 4) much more slowly. Genetic studies revealed that disruption or deletion of some of the betaI genes handicaps the growth of P. putida U in media containing n-alkanoic or n-phenylalkanoic acids with an acyl moiety longer than C4. However, all these mutants regained their ability to grow in media containing n-alkanoates as a result of the induction of betaII, but they were still unable to catabolize n-phenylalkanoates completely, as the betaI-FadBA enzymes are essential for the beta-oxidation of certain n-phenylalkanoyl-CoA derivatives when they reach a critical size. Owing to the existence of the betaII system, mutants lacking betaIfadB/A are able to synthesize new poly 3-OH-n-alkanoates (PHAs) and poly 3-OH-n-phenylalkanoates (PHPhAs) efficiently. However, they are unable to degrade these polymers, becoming bioplastic overproducer mutants. The genetic and biochemical importance of these results is reported and discussed.

Acids, Acyclic↗

IB-96212, a novel cytotoxic macrolide produced by a marine Micromonospora. I. Taxonomy, fermentation, isolation and biological activities.

A novel bioactive macrolide, IB-96212 has been isolated from the fermentation broth of a marine actinomycete, L-25-ES25-008. The strain belongs to the genus Micromonospora. The macrolide showed a very strong cytotoxic activity against P-388, and lower but significant activity against A-549, HT-29, and MEL-28 cell lines. We describe the isolation, taxonomy and fermentation of the producing strain as well as the isolation of IB-96212.

Anti-Bacterial Agents↗

[Use of skull radiography in craniocerebral injuries in childhood].

Authors review the usefulness of radiographic skull examination in childhood head injury. Two hundred and forty-two patients assisted at the emergency area were prospectively recorded during one year. Data of filiation and epidemiology and symptoms and signs posed by Leonidas as "high risk criteria" to have a skull fracture, were registered. AP and L X-Ray skull were performed in all patients. Thirteen (5.37%) of them had a fracture. Blood discharge from the ear and skull depressed fracture were more frequently found in the fracture group with statistically significant difference (p less than 0.05 and p less than 0.01, respectively). The probability of positive finding was 8.8 for blood discharge from the ear, 17.6 for skull depressed fracture and 4.4 for bilateral black eyes. Because of no correlation between clinical and radiological findings, the radiographic skull examination must be systematically performed in every head injury if the purpose is to diagnose a fracture.

Adolescent↗

Rural health care in Mexico?

A very large percentage of Mexico's population living in rural areas lacks resources for health care. Any new effort to provide such care must emphasize the health of the infant population because of the high percentage of infants in the country. Plans made at the national level have not been correlated with the conditions that exist in rural areas. For example, the majority of university programs are oriented toward urban medical practice, and the construction of more schools of medicine to solve the problem of doctors in rural areas is based on a mistaken premise. This problem has not been solved even in developed countries such as the United States where, as in Mexico, graduates in medicine migrate to the cities where optimal conditions are met for practicing the type of medicine for which they have been trained. Furthermore, it is both expensive and illogical to maintain urban doctors in rural areas where they cannot practice their profession for lack of resources; to do so is to deny the purpose of their education (27). Conventional schools of medicine, for reasons of investment and of structure, should teach only very selected groups of students who, on finishing their training, are fully capacitated to practice specialized medicine. A different system is required if we are to provide adequate health care in the rural communities. A system such as that described herein, adapted to the real need of rural communities, would avoid the necessity to create dysfunctional bureaucracies and would not destroy those institutions which have proved useful in the past. This study should be considered as one of the many pilot programs that should be initiated in order to determine the type of program that would best solve the problem of health care in rural Mexico. Other programs already being considered at the National Autonomous University of Mexico include the A36 plan of the Faculty of Medicine, now in operation; the work of C. Biro carried out in Netzahualcoyotl City (both focused on providing medical care to the urban poor); and the Open University program. Unless an efficient program designed to meet the needs of rural communities is quickly put into operation, Mexico will, in the near future, be facing the same problems now confronting Southeast Asia.

Community Medicine↗

Electron microscopic evidence for linear insertion of bacteriophage MU-1 in lysogenic bacteria.

Temperate bacteriophage Mu-1 was used to generate a lysogenic derivative of the F'lac episome of Escherichia coli. Intact, covalently circular molecules of F'lac and lysogenic F'lac Mu(+) deoxyribonucleic acid (DNA) were isolated and examined by electron microscopy. The mean contour lengths of F'lac and F'lac Mu(+) molecules were 37.6 +/- 0.4 mum and 53.2 +/- 0.4 mum, respectively. The mean difference, 15.6 mum, is similar to the mean contour length of 12.9 +/- 0.1 mum obtained for linear DNA molecules released by osmotic shock from mature phage Mu-1 virions. These results provide direct physical evidence that phage Mu-1 integrates by linear insertion of its genome into the DNA of lysogenic host bacteria. Chemical and physical analyses of phage Mu-1 DNA indicate that it is similar to E. coli DNA in respect of gross base composition, buoyant density, and melting temperature.

Adenine↗

[Clinical research].

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Education, Medical↗