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Biomedical subjects

L Fernandez

Publications and source records attributed to L Fernandez.

100 records · Page 6Linked to original sources
PubMedDate not supplied

Substituent effects on electrophilicity of flavins: an experimental and semi-empirical molecular orbital study.

The reactivities of the triplet excited states of several flavins with different N(10)-phenyl substituents have been found to be very similar. There is a good correlation between semi-empirical molecular orbital calculations at the MINDO/AM1 level and observed redox potentials. However, the most interesting observation is that the substituent effects are very small; this suggests that the N(10)-phenyl substituents are nearly perpendicular to the plane of the main ring due to their steric interactions with the main isoalloxazine system. Computed calculations as well as the fact that similar absorption maxima are obtained for 3-methyl-10-phenylisoalloxazine and 3-methyl-10-methylisoalloxazine are in agreement with this prediction.

Flavins↗
PubMedDate not supplied

Increased apoptosis in acute puromycin aminonucleoside nephrosis.

Acute puromycin aminonucleoside nephrosis (PAN) in rats is characterized by heavy proteinuria associated with renal hypercellularity. The role of apoptosis in the resolution of renal hypercellularity was investigated in PAN. To study the participation of apoptosis in PAN, renal tissues were collected from nephrotic and control rats on weeks 1, 2 and 7 after a single puromycin aminonucleoside injection. Apoptosis was evaluated by light and electron microscopy. Apoptotic DNA fragmentation was detected by TUNEL staining. Renal tissues were also evaluated by the presence of leukocyte common antigen (LCA), ED1 (macrophages) and proliferating cell nuclear antigen (PCNA) with corresponding monoclonal antibodies. An increased number of apoptotic (TUNEL+) cells was observed in the glomerulus at week 1. Electron microscopy analysis showed glomerular apoptosis mainly in endothelial cells. In the interstitium and tubules, increased apoptosis was observed at weeks 1 and 2. Increased apoptosis was accompanied with increased LCA+, ED1+ and PCNA+ cells in the interstitium and with increased PCNA+ cells in tubules. There was a high significant correlation between the number of apoptotic cells and the number of interstitial LCA+, ED1+ and PCNA+ cells. Tubular PCNA expression was correlated with tubular apoptosis. We also observed significant correlation between glomerular, interstitial and tubular apoptosis with proteinuria during the nephrosis. Double staining analysis showed that about 13% of interstitial or tubular apoptotic cells were positive for PCNA. All these values returned to normal by week 7. These results indicate that apoptosis is involved in the repairing process of this disease model.

Acute Disease↗
PubMedDate not supplied

The maturing kidney: development and susceptibility.

Kidney morphogenesis is accomplished by the coordinated interaction of molecular signals that culminate in the production of an organ that is architecturally and functionally ready for extrauterine, free life. In humans, nephrogenesis is completed before birth. However the kidney continues to mature both from a functional and anatomical point of view. Throughout its development, the kidney is susceptible to a variety of injurious agents. This brief review considers the basic mechanisms of kidney organogenesis and functional maturation. To illustrate some concepts, the renal alterations caused by interference with a normal regulatory system, the renin-angiotensin system is discussed.

Animals↗
PubMedDate not supplied

[Dependence disorders in psychopathology].

Research concerning the psychopathological aspects of dependence implicates a wide range of behaviors reassembled under the term of "dependence behaviors": sexual, medical, alcoholic and tobacco dependencies. Speech samples of dependent subjects show that encountering the object of dependence (product, element, ...) introduces a particular form of organized psychological processes. According to several authors, psychopathological dependence can be attributed to: early personality development; failures in the separation-individuation processes; disorders in mother-infant interactions; and a deficit in the psychological functioning of the subjects. For psychopathology, the dependence cannot be reduced to physiological dependence on the product but is understood rather in terms of a complex process indicative of either specific or non-specific suffering which is addressed by abused substance that represents a solution--the effects of which constitute the addictive process. Understanding this process requires an analysis of the psychopathological dependence from a triple meta-psychological viewpoint (topographical, dynamic, economic). Such analysis allows for a psychoanalytical theoretical interpretation of dependence based on three models: pleasure, narcissism and stress reduction. At the same time, the analysis extends the examination of psychopathological dependence towards issues concerning the body. Such body issues are critically placed between the biological and the psychological processes.

Dependent Personality Disorder↗
PubMedDate not supplied

[Benzodiazepine addiction and symptoms of anxiety and depression in elderly subjects].

The relative works to the psychopathological aspects of benzodiazepines (BZD) addiction in elderly persons make the object of a large debate because the question of addiction remains whole. They concern: 1) the influence of age on the level of consumption of the BZD. The research permits to clear 4 explanatory major factors of the relation observed between age and the consumption of BZD: a) the morbidity increased of the aged people, b) the impact of the painful life events, c) the social isolation, d) the weight of the medical prescription; 2) the concepts of dependence (evolution of the definitions, type of physical, psychic or psychopathological dependencies) and of addiction (definitions, place in the international classifications, psychopathological perspective); 3) the reports of the anxiety and the depression with BZD addiction in elderly persons. To the look of these works, the objectives of this present study were to examine the variability of BZD addiction on the one hand within a population weakened by the effects of age (apparition of a chronic illness, for example) and on the other hand the relations that the anxious and depressive symptoms maintain with BZD addiction in elderly persons. Two self-questionnaires were administered: 1) BZD addiction scale, 2) Hospital Anxiety Depression Scale (HAD) to 28 elderly (18 women and 10 men; mean age is 73.25 years). To the exit of this work, the results put in evidence go in the sense of our hypotheses but cannot be generalized to the set of the elderly consumers of BZD, they let appear that age, the depression and the association anxiety/depression predict meaningful manner BZD addiction. Indeed, with regard to age, the polypathology as well as the changes of life induced by the aging process involved BZD addiction in old people. The old age can engender a depression that results in addictive behavior. However, anxiety alone is not experienced before drug addiction in a significant way. This result can explain itself by the fact that the anxiety is a symptom of depression. The present research is unique in several important aspects. First, the study shows that drug addiction in old people cannot be reduced to physiological addiction on product but understood in terms of a complex process requiring an analysis of the psychological addiction on product. Second, BZD addiction in the elderly acts as a psychological/existential medical care. Future research is needed to examine the psychological and psychopathological links that old people maintain with their drug medication.

Aged↗
PubMedDate not supplied

GLUT1 expression in human breast carcinoma: correlation with known prognostic markers.

BACKGROUND: Breast cancers have been shown to have increased glucose uptake and utilization, and to express the facilitative glucose transporter Glut1. The aim of this study was to determine the biological significance of Glut1 expression in breast cancer. METHODS: Paraffin sections of 118 breast cancers were immunostained with antibody to Glut1. The percent of Glut1-positive cancer cells in each tumor was correlated with known prognostic markers, and with patient outcome. RESULTS: Glut1 was expressed in 42% of the tumors. Glut1 immunoreactivity correlated positively with the proliferative activity as determined by Ki-67 immunostaining, and with the total histologic score, and showed negative correlation with bcl-2 immunostaining. There was no correlation between the percent of Glut1-immunoreactive cancer cells and estrogen receptor status, tumor size, or lymph node status. CONCLUSIONS: 1) Glut1 expression is increased in breast cancers with higher grade and proliferative activity, and 2) glucose transport in the majority of breast cancers may be mediated by a glucose transporters other than Glut1.

Breast Neoplasms↗
PubMedDate not supplied

Transforming growth factor alpha (TGF-alpha) expression in biopsies of colorectal carcinoma is a significant prognostic indicator.

BACKGROUND: Predicting the outcome of patients with colorectal adenocarcinoma (CRCA) prior to surgery would be valuable in selecting high-risk individuals who may benefit from pre-operative adjuvant therapy. The aim of this study is to determine whether the expression of TGF-alpha in preoperative biopsies of patients with CRCA constitutes a significant prognostic indicator. METHODS: We studied the expression of TGF-alpha in preoperative biopsies of 106 patients with CRCA, who had at least 5 years follow-up, using an anti-TGF-alpha monoclonal antibody and utilizing the ABC immunoperoxidase technique. For survival analysis, we used the actuarial survival method, and the Log Rank test for statistical significance. RESULTS: CRCAs with low TGF-alpha expression (less than 25% of the tumor cells immunoreactive for TGF-alpha) had a significantly poorer survival than those with high TGF-alpha expression (more than 25%). After excluding from analysis biopsies showing mucinous or poorly differentiated CRCA, known predictors of poor prognosis, the results remained significant (p = 0.0289). CONCLUSION: It is concluded, therefore, that low or absent expression of TGF-alpha in pre-operative biopsies of patients with CRCA, as detected by immunohistochemistry, is a significant predictor of an unfavorable outcome.

Actuarial Analysis↗