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Biomedical subjects

L Rosa

Publications and source records attributed to L Rosa.

At least 19 recordsLinked to original sources
PubMed1992

[Nucleolar asynchrony in human acute myeloid leukemia blast cells].

Nucleolar asynchrony (the presence of "active" and "sleeping" nucleoli with respect to the RNA synthesis in one and the same nucleus) was noted and studied in blastic cells of the peripheral blood in patients of acute myeloid leukemias (M1 - M4 according to FAB classification) by means of light microscopy of smears after visualization of RNA containing structures. Nucleolar asynchrony seems to be a regular phenomenon in a certain number of blastic cells in the peripheral blood and has been also verified by electron microscopy. No significant difference has been noted in the incidence of blasts with nucleolar asynchrony between the peripheral blood of patients treated and untreated by cytostatic therapy at the time of taking samples for the present study: The presence of the nucleolar asynchrony/might contribute to the resistance of a certain population of leukemic blasts to the cytostatic therapy. This supposition is supported by the present experiments "in vitro" on mouse leukemic myeloblasts sensitive and resistant to Doxorubicin. The Doxorubicin resistant myeloblasts were characterized by a significantly larger incidence of the nucleolar asynchrony as compared with myeloblasts of the Doxorubicin sensitive cell line.

Acute Disease↗
PubMed1991

Brain protection during circulatory arrest.

Previous nuclear magnetic resonance studies in this laboratory have shown a beneficial biochemical effect of antegrade cerebroplegia (CP-A) during hypothermic circulatory arrest. This study compared CP-A with other methods of cerebral protection during hypothermic circulatory arrest to assess the clinical utility of this technique. Twenty-three sheep were divided into four groups: systemic hypothermia alone (SYST) and systemic hypothermia combined with external cranial cooling (EXTNL), retrograde cerebroplegia (CP-R), or CP-A. Cardiopulmonary bypass was started, and the sheep were cooled to 15 degrees C and subjected to 2 hours of circulatory arrest. Cardiopulmonary bypass was restarted, and the animals were rewarmed and weaned from cardiopulmonary bypass. Serial neurological examinations were performed and hourly scores assigned until the animals were extubated. Postanesthetic neurological scores improved in all groups throughout the 6-hour recovery period except the CP-R group. The improvement over time for these scores was similar for the EXTNL and CP-A groups and significantly better than for the SYST or CP-R groups (p = 0.004). The CP-A group had 5 of 7 animals with deficit-free survival despite the similarity in recovery of baseline brainstem function. We conclude that both antegrade infusion of cerebroplegia and external cranial cooling confer distinct cerebroprotective effects after a protracted period of hypothermic circulatory arrest when compared with the other methods studied.

Animals↗
PubMed1990

MRI characterization of 9L-glioma in rat brain at 4.7 Tesla.

In vivo estimation of intracranial tumor progression is important in tumor treatment response studies in animal models. High resolution MR images at 4.7 T of 9L-gliomas stereotactically implanted in Fisher-344 rat brains were obtained. Due to elongation of T1 at higher fields, tissue contrast is diminished in T1-weighted images. However, normal anatomy and vasogenic edema are clearly discerned in T2-weighted images (echo times of greater than 50 ms and recycle times of greater than 2 sec). Tumor tissue is not always clearly delineated. Images obtained after administration of contrast agents (Gadolinium DTPA), with short TR (0.6 sec) selectively enhanced the tumorous tissue, with little effect upon normal tissue and edema. Good correlation of enhanced tumor lesions has been observed with histological examination of formalin fixed brains. Relaxation times (T1 and T2) of tumor and normal tissues were measured using stimulated-echo and multi-echo sequences, respectively. Serial images corresponding to tumor growth were recorded, from which tumor volume progression was monitored.

Animals↗
PubMed1990

Transbilayer redistribution of phosphatidylserine in erythrocytes of a patient with autoerythrocyte sensitization syndrome (psychogenic purpura).

We have investigated a female patient with autoerythrocyte sensitization syndrome (AES syndrome), having a positive skin response to her own red blood cells (RBC) and to phosphatidylserine (PS). Using 2,4,6-trinitrobenzenesulfonic acid (TNBS), bee venom phospholipase A2 and merocyanine 540 binding, we have demonstrated that in RBC of patient more than 50% of PS is redistributed into the outer leaflet of the plasma membrane. Using homologous RBC from a healthy donor we were able to induce transbilayer PS redistribution by incubation with the patient plasma. The presence of immunoglobulin E against cardiolipin and PS was proved in patient's plasma. We elaborated a method for cytoskeleton visualization using indirect immunofluorescence technique. We found disorders in cytoskeleton organization in RBC of the patient. We recommend in vitro testing for AES syndrome diagnosis. The positive effect of chlorpromazine treatment is described.

Actins↗
PubMed1989

Rey-Auditory Verbal Learning and Rey-Osterrieth Complex Figure Design performance in Alzheimer's disease and closed head injury.

Performance on the Rey-Auditory Verbal Learning (R-AVL) and Rey-Osterrieth Complex Figure Design (R-O CFD) tests was examined in patients (N = 94) with dementia of the Alzheimer's type (DAT) and closed head injury (CHI). On the R-AVL, DAT patients demonstrated considerably greater impairment than CHI patients, along with a flat learning/retention curve that showed negligible improvement with repeated trials, recency effects only, and an excessive number of word intrusions (confabulation) on the recognition trial. CHI patients demonstrated both a recency and primacy effect along with improvement over repeated trials (positive slope learning curve). Both groups demonstrated impairment R-O CFD recall; the DAT group again displayed substantially greater copying and recall deficits. Clinical guidelines are given for the use of the R-AVL and R-O CFD for these two patient populations.

Adult↗
PubMed1989

Missed fractures of the cervical spine.

Two cases of missed injuries of the cervical spine are presented, with a description and a discussion of the circumstances of the injuries. This information hopefully will alert medical personnel to situations where these injuries may be overlooked.

Adult↗
PubMed1986

Response variability of human brain tumors to AZQ in tissue culture.

In a series of 28 glioma-derived cell cultures and 6 non-gliomatous CNS tumors, AZQ has been found to have varying degrees of growth inhibiting or cytotoxic activity in nearly all lines tested at doses greater than 100 mcg/ml. At dose levels comparable to the clinically achieved levels (1 mcg/ml), AZQ was found to have a cytotoxic effect in 8 of 28 glioma-derived and 2 of 6 non-gliomatous cell lines tested. These findings suggest that AZQ has activity against certain glioma-derived cells in culture at a response ratio similar to that seen in vivo. There, appear to be significant differences in the degree of responsiveness in different patients' tumor cells which can be detected in vitro prior to clinical treatment.

Antineoplastic Agents↗
PubMed1979

[Malnutrition].

Explore the source record for details and available documents.

Humans↗
PubMed1976

Phosphorylation in isolated chloroplasts coupled to dichlorophenyldimethylurea-insensitive silicomolybdate reduction.

1. The electron transport in isolated chloroplasts with silicomolybdate as electron acceptor has been reinvestigated. The silicomolybdate reduction has been directly measured as deltaA750 or indirectly as O2 evolution (in the presence or absence of ferricyanide). 2. Silicomolybdate-dependent O2 evolution is inhibited to a similar extent by 3-(3,4-dichlorophenyl) 1, 1-dimethylurea (DCMU) or dibromothymoquinone (DBMIB), indicating the existence of two different sites of silicomolybdate reduction: one before the DCMU block (i.e. at Photosystem II) and one after the DBMIB block (i.e. at Photosystem I). 3. Silicomolybdate-dependent O2 evolution is coupled to ATP synthesis with an ATP/2e- ratio of 1.0 to 1.1. The presence of ferricyanide inhibits this ATP synthesis (ATP/2e- ratio then is about 0.3). 4. Silicomolybdate-dependent O2 evolution is also coupled to ATP-synthesis in the presence of DCMU with an ATP/2e- ratio of 0.6-0.8 characteristic of Site II; in this case the electron transport itself is not affected by uncouplers or energy-transfer inhibitors. 5. The data are interpreted as a further demonstration that the water-splitting reaction is responsible for the conservation of energy at Photosystem II.

Adenosine Triphosphate↗