Biomedical subjects
Publications and source records attributed to L Rosa.
The phase transition of the Gross-Neveu model with N fermions is investigated by means of a nonperturbative evolution equation for the scale dependence of the effective average action. The critical exponents and scaling amplitudes are calculated for various values of N in d = 3. It is also explicitly verified that the Neveu-Yukawa model belongs to the same universality class as the Gross-Neveu model.
IL-13 is a Th2-derived pleiotropic cytokine that recently was shown to be a key mediator of allergic asthma. IL-13 mediates its effects via a complex receptor system, which includes the IL-4R alpha-chain, IL-4Ralpha, and at least two other cell surface proteins, IL-13Ralpha1 and IL-13Ralpha2, which specifically bind IL-13. IL-13 has been reported to have very limited effects on mouse B cells. It was unclear whether this was due to a lack of receptor expression, a disproportionate relative expression of the receptor components, or an additional subunit requirement in B cells. To determine the requirements for IL-13 signaling in murine B cells, we examined IL-13-dependent Stat6 activation and CD23 induction in the murine B cell line, A201.1. A201.1 cells responded to murine IL-4 via the type I IL-4R, but were unresponsive to IL-13, and did not express IL-13 receptor. B220(+) splenocytes also failed to signal in response to IL-13 and did not express IL-13 receptor. We transfected A201.1 cells with human IL-4Ralpha, IL-13Ralpha1, or both. Transfectants expressing either human IL-4Ralpha or human IL-13Ralpha1 alone were unable to respond or signal to IL-13. Thus, human IL-13Ralpha1 could not combine with the endogenous murine IL-4Ralpha to generate a functional IL-13R. However, cells transfected with both human IL-4Ralpha and IL-13Ralpha1 responded to IL-13. Thus, the relative lack of IL-13 responsiveness in murine B cells is due to a lack of receptor expression. Furthermore, the heterodimeric interaction between IL-4Ralpha and IL-13Ralpha1 is species specific.
CONTEXT: Therapeutic Touch (TT) is a widely used nursing practice rooted in mysticism but alleged to have a scientific basis. Practitioners of TT claim to treat many medical conditions by using their hands to manipulate a "human energy field" perceptible above the patient's skin. OBJECTIVE: To investigate whether TT practitioners can actually perceive a "human energy field." DESIGN: Twenty-one practitioners with TT experience for from 1 to 27 years were tested under blinded conditions to determine whether they could correctly identify which of their hands was closest to the investigator's hand. Placement of the investigator's hand was determined by flipping a coin. Fourteen practitioners were tested 10 times each, and 7 practitioners were tested 20 times each. MAIN OUTCOME MEASURE: Practitioners of TT were asked to state whether the investigator's unseen hand hovered above their right hand or their left hand. To show the validity of TT theory, the practitioners should have been able to locate the investigator's hand 100% of the time. A score of 50% would be expected through chance alone. RESULTS: Practitioners of TT identified the correct hand in only 123 (44%) of 280 trials, which is close to what would be expected for random chance. There was no significant correlation between the practitioner's score and length of experience (r=0.23). The statistical power of this experiment was sufficient to conclude that if TT practitioners could reliably detect a human energy field, the study would have demonstrated this. CONCLUSIONS: Twenty-one experienced TT practitioners were unable to detect the investigator's "energy field." Their failure to substantiate TT's most fundamental claim is unrefuted evidence that the claims of TT are groundless and that further professional use is unjustified.
Nucleoli were studied in all stages of the granulopoietic proliferating compartment in the bone marrow of patients suffering from chronic myeloid leukemia to provide an information on the incidence of the nucleolar functional asynchrony (imbalance) in these cells. The nucleolar functional asynchrony is morphologically expressed by the presence of "active" large nucleoli with a relatively uniform distribution of ribonucleic acid (RNA) and "resting" ring shaped nucleoli with RNA only in their peripheral part in one and the same cell. This phenomenon was noted in a small but constant percentage of myeloblasts and decreased in myelocytes regardless of the phase of the disease and therapy. In addition, the nucleolar functional asynchrony was also noted in all stages of the granulopoietic proliferating compartment of control not-leukemic persons.
Explore the source record for details and available documents.
Nucleoli were studied in circulating myeloblasts of myeloblastic (FAB M1, M2), promyelocytic (FAB M3) and myelomonocytic (FAB M4) acute myeloid leukemias (AMLs) using a cytochemical procedure for the demonstration of RNA. In patients untreated with cytostatic chemotherapy, myeloblasts of myeloblastic acute leukemias possessed less frequently "active large" nucleoli and more frequently "inactive" micronucleoli in comparison with other investigated types of AMLs. When myeloblasts were classified according to the presence of functionally dominant nucleoli, the higher percentage of "terminal" myeloblasts containing only micronucleoli in this type of AML was significantly reduced in patients treated with the cytostatic chemotherapy. In patients suffering from promyelocytic leukemia treated with cytostatic chemotherapy, the decreased percentage of myeloblasts containing functionally dominant active large nucleoli was accompanied by the increased incidence of myeloblasts with functionally dominant "resting" ring shaped nucleoli. In myelomonocytic AML no significant differences were noted between patients untreated or treated with the cytostatic chemotherapy in the incidence of main nucleolar types in myeloblasts and myeloblasts classified according to the presence of functionally dominant nucleoli. Thus a further biological specificity might exist among leukemic blasts in various types of AMLs which should be considered for a rational approach to the therapy of these malignancies. In addition, the cytostatic chemotherapy did not influence incidence of the nucleolar asynchrony in myeloblasts of all investigated types of AML.
The investigation of nucleoli is a simple but useful complementary approach for the evaluation of individual leukemic cells in addition to other hematological laboratory procedures. Since main nucleolar types represent the morphological expression of nucleolar biosynthetic activities, i.e. RNA transcription, the incidence of functionally dominant nucleolar types in leukemic cells reflects the state of these cells which is related to that transcription. Similarly, the investigation of AgNORs in individual leukemic cells may provide a complementary useful information on their proliferation activity.
The authors examined the concentration of erythrocyte zinc-protoporphyrin (ZPP) by a haematofluorometric method in 175 women during delivery and the levels in their children. They assessed basic haematological indicators, the number of red cells, their volume, number of reticulocytes, haemoglobin concentration, haematocrit and sideraemia. All were average values within the physiological range in both examined groups. Statistical evaluation revealed a significant difference between mean values of sideraemia in mothers and children and mean values of the erythrocyte ZPP in both groups. The authors found also a medium significant correlation between ZPP and the erythrocyte volume and the erythrocyte volume and sideraemia. The correlation of different indicators was more marked after classification of the examined women and neonates into subgroups by haemoglobin concentrations and ZPP. In the subgroup of mothers with Hb values lower than 115 g/l a positive correlation was found with the number of reticulocytes red cell volume and sideraemia. In the subgroup of anaemic women (Hb concentration lower than 105 g/l) a negative correlation with the foetal sideraemia was found.
On the present study the authors evaluate the utility of electrophysiologic examination in uraemic polyneuropathy. A group of 19 uraemic patients in chronic dialysis underwent the Blink reflex and BAEPSs study to evaluate the alterations of nervous pathways. The results obtained were compared with those of a group of 10 healthy patients comparable for age and sex. The electrophysiologic parameters have been statistically compared with the plasma levels of vit. B12. folic acid, PTH and beta-2-microglobulin. The results show a significant difference of uremic patients compared with the healthy ones for the Blink reflex (ipsilateral and contralateral R2 responses). Also BAEPSs show significant alterations in the uraemic group (latencies of the III, V components). A statistically significantly inverse correlation is present between folic acid values and blink reflex R1 and R2 responses. Therefore our study shows the existence of a combined degeneration of central and peripheral nervous pathways in chronic uraemic patients. We believe that the decrease in folic acid concentration found in our study may be one of the causes of the beginning and then of the worsening of neurologic damage.
Explore the source record for details and available documents.
The incidence of micronucleoli was investigated in lymphocytes of the peripheral blood of patients suffering from B chronic lymphocytic leukemia (B CLL). The cytostatic monochemotherapy with chlorambucil apparently produced in these cells an increased incidence of micronucleoli which are known to represent the morphological expression of the inhibition of the nucleolar ribonucleic acid (RNA) transcription. Similarly, the percentage of lymphocytes with micronucleoli was increased after the cytostatic therapy disregarding whether such nucleoli were present in these cells as the only nucleolar type or in addition to other nucleolar types as satellite nucleoli.
Satellite nucleoli were studied in lymphocytes of patients suffering from various stages of B chronic lymphocytic leukaemia without and after treatment with cytostatic monotherapy with chlorambucil. The percentage of lymphocytes with satellite nucleoli in the peripheral blood of investigated patients was very constant and showed only a statistically non-significant slight trend to decrease in the most advanced stage of the disease. In contrast, the count of these cells increased in advanced stages of the disease, and decreased after the cytostatic chemotherapy. From the methodological point of view, satellite nucleoli may be easily visualized by means of a simple staining for RNA with acidified basic dyes without fixation. Such staining provided similar results as cytochemical immunoreactions for the characteristic nucleolar protein B23.
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.
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.
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.
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.
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.