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Biomedical subjects

M Ciubotaru

Publications and source records attributed to M Ciubotaru.

10 recordsLinked to original sources
PubMed2001

Severe orthostatic hypotension following weight reduction surgery.

Surgical interventions for morbid obesity are common practice in many countries, especially when other treatment options have failed or when rapid weight loss is desired. The association between weight and blood pressure is well established, especially the paradigm of obesity-related hypertension. We describe a 45-year-old obese woman with a medical history of hypertension and type 2 diabetes mellitus who lost 57 kg within a few months after a weight reduction surgery. She suffered from severe orthostatic hypotension, which probably resulted from sympathetic nervous system dysfunction. Our patient's clinical status improved with pharmacological interventions, but her symptoms resolved completely after she gained weight following a surgical reversal of the gastric partitioning owing to a local complication. Autonomic nervous system activity does change with the changes in body weight, but after evaluation of this patient, we believe that rapid weight loss may impair sympathetic function and blood pressure control. Although losing weight is a known treatment option for hypertension, exaggerated reversal of obesity-related hypertension might result in orthostatic hypotension.

Combined Modality Therapy↗
PubMed1999

DNA-induced conformational changes in bacteriophage 434 repressor.

Although bacteriophage 434 repressor binds to its specific DNA sites only as a dimer, formation of the dimers in solution occurs at concentrations three orders of magnitude higher than those needed to bind the 434 operator DNA. Our results suggest that both specific and non-specific DNA induce conformational changes in repressor that lead to formation of repressor dimers. The repressor conformational changes induced by DNA occur at concentrations much lower than those needed for binding of repressor, suggesting that the alternative conformations of repressor persist even if the protein is not in direct contact with DNA. Hence, DNA acts in a "catalytic" fashion to induce a steady-state amount of an alternative repressor conformation that has an enhanced affinity for its specific binding site. These findings suggest that the repressor conformer induced by non-specific DNA is the form of the repressor that is optimized for searching for DNA binding sites along non-specific DNA. Upon finding a binding site, the repressor protein undergoes an additional conformational change that allows it to "lock-on" to its specific site.

Acrylamide↗
PubMed1995

Vaccination with a recombinant V alpha domain of a TCR prevents the development of collagen-induced arthritis.

A recombinant TCR domain, derived from a T cell hybridoma that recognizes an immunodominant type II collagen epitope, was used to vaccinate against collagen-induced arthritis in DBA/1 (H-2q) mice. The recombinant TCR domain comprises VA11.1-JA17 gene segments and is representative of the V alpha domains expressed by oligoclonal T cells in this disease model. Vaccination of mice 28 days before type II collagen (CII) immunization with this V alpha 11.1 domain resulted in a significantly decreased incidence of arthritis in DBA/1 mice, in contrast to vaccination with a V alpha 4-J alpha 40 domain derived from an encephalitogenic T cell hybridoma specific for MBP. Disease blockade is accompanied by a reduction in T and B cell responses to both the immunogen bovine CII and the autoantigen murine CII. V alpha 4 and V alpha 11.1 domains were found to be highly immunogenic in DBA/1 mice, inducing both T cell proliferation and the production of V alpha specific Abs, indicating that the vaccination effect of V alpha 11.1 is specific. This is the first report of V alpha-directed immunotherapy in an autoimmune disease model and demonstrates the potential use of recombinant TCR vaccines in the treatment of autoimmune diseases that involve oligoclonal autoreactive T cells.

Amino Acid Sequence↗
PubMed1991

The hormones--a model for a new understanding of cell differentiation process. Part II. Why does mitosis avoid those highly differentiated cells?

This new replicative model here explained is the result of the fact that, even if replication and transcription are distinct events during the cell evolution, they are functionally correlated, being responsible both for the main features of the cell, and for hormones affinity, too. This model of replication suggests the spreading of replication, in both directions symmetrically from the origin site of each replicon, as well as a simultaneous replication of both DNA strands, despite the fact that one of them was until now called "lagging" strand. These two events are explained by initiation of each DNA catena with distinct RNA polymerase forms depending on the presence or absence of the sigma 70 recognition factor (or its beta gamma analogous eukaryotic factor). The arguments sustaining these events were gathered from many already known genetic studies, some of them being here supposed to new interpretations (for instance, the phi x 174, M13 phages replication models). The disposition of both DNA strands during replication allows the intervening of both RNA polymerase types only in RNA primer synthesis. However, other physical restrictive interactions suggested theoretically prevent the going on of RNA polymerases activity like they do during transcription. This is the main reason that determines the exposure of DNA conformational changes occurring in the replication. These explanations may bring a possible new light about the "mystery" of the phenomenon producing the "replicative eye" inside the double helical structure of DNA.

Animals↗
PubMedDate not supplied

The hormones--a model for a new understanding of cell differentiation process. Part I. Differentiation--an individual cell option?

From the beginning I want to explain some interesting notions about cytodifferentiation, these being seen, in my view, like an Instructive Informatory Theory. Then, I tried to present the sustaining arguments for an extracellular differentiation. These arguments reveal that final decision in differentiation process are the receptor molecules. Therefore, I present some actual questions arisen about the correlations between receptors and secondary messengers. The hormones action models are the single way to clear up the vagueness about the nucleus-receptor connection.

Animals↗