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Biomedical subjects

M Carmona

Publications and source records attributed to M Carmona.

At least 55 records · Page 3Linked to original sources
PubMed1996

Transforming growth factor-alpha (TGF-alpha) and epidermal growth factor-receptor (EGF-R) immunoreactivity in normal and pathologic brain.

Transforming growth factor alpha (TGF-alpha) and epidermal growth factor-receptor (EGF-R) immunoreactivity is observed in the majority of neurons, and in maturing astrocytes, in the developing and adult brain of humans and different species of animals. TGF-alpha and EGF-R co-localize in most neurons and maturing astrocytes, suggesting that most TGF-alpha-producing cells are EGF-R-expressing cells. TGF-alpha and EGF-R immunoreactivity decrease in damaged areas following different insults. However, EGF-R appears in reactive glia, mostly reactive astrocytes, within and surrounding the damaged areas. TGF-alpha and EGF-R immunoreactivity is found in neurons of patients affected by Alzheimer's disease and other forms of dementia, and in neurons of patients suffering from epilepsy owing to different causes, thus pointing to the conclusion that TGF-alpha does not play a significant role in these pathologies. However, EGF-R immunoreactivity occurs in reactive astrocytes and microglia in subacute but not chronic lesions in human cases. Since TGF-alpha is a membrane-anchored growth factor, which may be cleaved leading to the formation of soluble forms, and both the membrane-anchored and soluble forms have the capacity to activate the EGF-R, it is feasible that TGF-alpha in the nervous system may act upon EGF-R-containing neurons through different mechanisms. In addition to distant effects resulting from the release of soluble TGF-alpha, local effects may be produced by establishing direct cell-to-cell contacts (juxtacrine stimulation), or in cells expressing both TGF-alpha and EGF-R (autocrine stimulation).

Animals↗
PubMed1996

Skeletal muscle ultrastructural pathology in Serinus canarius infected with Plasmodium cathemerium.

Serinus canarius infected with Plasmodium cathemerium was used as an animal model in order to study the skeletal muscle compromise in malaria. Pectoral muscle biopsies were obtained from 7 infected female birds. The transmission electron microscopic study showed alterations of contractile and sarcotubular systems, mitochondrial abnormalities, lysosomal proliferation and nuclear pyknosis. The sarcolemma looked disrupted and separated from the necrotic fibres. Capillary abnormalities included endothelial degeneration with proliferation of lysosomal structures, penetration of endothelial cell by the parasites and necrosis. A mononuclear cell infiltrate formed by plasmocytes, lymphocytes and macrophages was observed. This investigation shows that skeletal muscle is an important target tissue for some malaria parasites.

Animals↗
PubMed1995

Reversal of severe hepatic veno-occlusive disease by combined plasma exchange and rt-PA treatment.

We report the successful treatment of a case of severe hepatic veno-occlusive disease (VOD) by combined treatment with exchange plasmapheresis and fibrinolysis with rt-PA. Very advanced alterations of hepatic vascular circulation, evaluated by Doppler sonography, reverted to normal after treatment. Severe VOD, defined by McDonald's criteria, produces a mortality of 98%. This case suggests that this new method of combined treatment might contribute to changing the usually bad prognosis of this clinical condition.

Adult↗
PubMed1995

Presentation of a PCR-nuclease protection strategy for minimal residual disease monitoring in B-ALL.

Methods for detecting residual malignant cells in patients suffering from lymphoid malignancies have neither been sufficiently sensitive nor easy to routinize, hampering a potential prediction of disease outcome. Taking advantage of clone-specific DNA sequences, generated during lymphocyte differentiation and the polymerase chain reaction, some strategies have been developed for several groups. Up to now the most specific and sensitive methodology, which consists of designing leukemia-specific oligonucleotides, requires sequencing of the complementary determining region III-DNA for each particular patient and is too laborious to be applied to each case for routine monitoring in most hospital laboratories. In an attempt to achieve an easy way to detect residual malignant cells in B lymphoproliferative diseases, we have used a new PCR-based approach, named here as PCR-nuclease protection assay, consisting of: (i) amplification of DNA segments corresponding to the complementarity determining region III of the immunoglobulin heavy chain genes from samples at disease diagnosis; (ii) isolation of the disease-specific single-stranded DNA; (iii) labeling of the single-stranded DNA to generate specific probes; (iv) hybridization to amplified DNA from samples corresponding to different disease phases; and (v) digestion with S1-nuclease. Using this approach, we could detect one malignant cell in a background of 10(5) healthy cells. The sensitivity and specificity of this approach compares with those of the above mentioned specific oligonucleotide strategy in detecting residual malignant B cells. Moreover, this strategy is much less tedious and could be used by most hospital laboratories.

Base Sequence↗
PubMed1994

[Immunotherapy with interleukin-2 and allogenic LAK cells in a patient with acute myeloblastic leukemia].

At the present time the effectiveness of interleukin-2 (IL-2) administered together with IL-2 in vitro activated lymphocytes (LAK) in the treatment of malignant neoplasias is being assessed. We report the case of an 8 -year- old patient suffering from acute myeloid leukemia (AML) who had relapsed from an autologous bone marrow transplant (ABMT) and received a second ABMT in partial remission. After the second ABMT, the patient, who entered into a phase of complete remission (CR) but with a severe thrombocytopenia, was treated with IL-2 and allogeneic LAK cells obtained from his father. During treatment the lymphocyte subpopulations and cytolytic activity were assayed. Increases in the patient's lymphocytes with CD3- CD4- CD8- CD16+, CD3- CD4- CD8- CD56+, CD3- CD4- CD8+ CD56+ and CD3- CD4- CD8+ CD56+ phenotypes were observed and these were correlated with cytolytic activity measured against the K562 cell line. The patient remained in CR for longer (14 months) than after the first ABMT (5 months). The immune activation produced by this therapy could have had an antileukemic effect in the patient.

Child↗
PubMed1994

Febrile seizures.

Febrile seizures are commonly seen in emergency departments that treat children. Risk factors for initial and recurrent febrile seizures and epilepsy have been identified. Controversy still exists over the need for performing a lumbar puncture as part of the initial evaluation. Most children with a febrile seizure and meningitis present with an abnormal level of consciousness or have obvious meningeal signs. Emphasis should be placed on looking for a source of fever and reassuring and educating the caretakers.

Child↗
PubMed1993

Escherichia coli hha mutants, DNA supercoiling and expression of the haemolysin genes from the recombinant plasmid pANN202-312.

The hha gene of Escherichia coli was identified as modulating the expression of the haemolysin (hly) genes encoded by the recombinant plasmid pANN202-312. hha mutants harbouring plasmid pANN202-312 showed increased haemolysin production. The product of the hha gene, the Hha protein, shows strong homology to the YmoA protein of Yersinia enterocolitica, which plays a role in the thermoregulation of various Y. enterocolitica virulence genes. We show in this study that the Hha protein modulates the expression of haemolysin at the transcriptional level in cells harbouring plasmid pANN202-312. In addition, hha mutants show alterations in the level of plasmid DNA supercoiling. This suggests that the hha mutation increases haemolysin expression through changes in the DNA topology. This hypothesis is supported by our finding that gyr mutations, inhibitors of DNA gyrase such as novobiocin, or growth in conditions reported to reduce levels of negative supercoiling, such as low osmolarity medium, increase haemolysin production.

Base Sequence↗
PubMed1992

A fully automated method for mononuclear bone marrow cell concentration.

We describe our experience in processing 40 bone marrow aspirates harvested for autotransplantation from patients with several hematological diseases using the CS-3000 blood cell separator. The bone marrow of the first 30 patients was processed by a semiautomated method, and a fully automated procedure was used for the remaining 10 cases. Both procedures were developed in our laboratory and yielded a similar average mononuclear cell recovery of 87.78% and 86.98%, respectively, and similar nucleated cell recovery (27.39% and 27.11%). The cloning efficiency of hematopoietic progenitor cells, measured as the total CFU-GM colony recovery in the in vitro cultures, did not differ between processed and recovered mononuclear cells. On the other hand, all the patients with transplants showed complete hematologic recovery, and the time to engraftment was similar to that described for other procedures. The automated procedure resulted in an average red cell removal of 97.81%, similar to the semiautomated procedure (94.19%), though with a narrower range (96.31-98.6% vs. 80.34-98.34%). The time taken to process a similar amount of bone marrow cell suspension was very different for each method: 1 hour for the fully automated vs. 2 1/2 hours for the semiautomated method to process 1,000 ml. Furthermore, the semiautomated procedure required the addition of homologous or irradiated plasma in a laminar air flow chamber, while the automated method is performed in a closed sterile system. We conclude that our procedure using the CS-3000 processor is an efficient method for fully automated large-scale processing of human bone marrow cells.

Adolescent↗
PubMed1991

Simultaneous kinetic determination of epinephrine and norepinephrine by the stopped-flow technique.

A stopped-flow method for the simultaneous determination of epinephrine and norepinephrine, two catecholamines with a wide spectrum of biological activity, is proposed. The method is based on the oxidation of these compounds with 1,10-phenanthroline-iron(III) complex, which is monitored by measuring the initial rate of change of the absorbance of the ferroin formed at 510 nm. The difference in kinetic behaviour between the two species was exploited by applying a modified version of the proportional-equation method for the resolution of epinephrine-norepinephrine mixtures at the micrograms ml-1 level over the ratio range 1:10-10:1, with an error of less than 5% and an average precision of about 2.5%. The method was successfully applied to the determination of the two catecholamines in pharmaceuticals.

Epinephrine↗
PubMed1991

The hha gene modulates haemolysin expression in Escherichia coli.

A mutation in the hha allele results in a large increase in the production of intracellular as well as extracellular haemolysin in Escherichia coli cells harbouring the haemolytic recombinant plasmid pANN202-312. This single gene mutation was located between 490 and 491.6 kb on the physical map of the E. coli chromosome. From the DNA sequence of hha a small polypeptide of 8629 Da was predicted and was expressed in minicells. The deduced polypeptide sequence did not show significant similarities to other characterized proteins related to the regulation of gene expression in E. coli, although it was shown that the hha mutation increases cytoplasmic synthesis of haemolysin.

Amino Acid Sequence↗
PubMed1989

Hypothalamo-pituitary-adrenal manipulations and stress ulcerations in rats.

Both gastric ulceration and activation of the hypothalamo-pituitary adrenal axis are considered integral to the stress response, and a causal relationship between the two has been suggested. In the present study, corticosterone secretion in rats was either stimulated with CRF or lowered with metyrapone during a known ulcerogenic stress. Reduction of circulating corticosterone during the stress had no effect on ulceration severity compared to saline-treated stressed control rats. Treatment with CRF in stressed animals reduced ulceration severity. The mechanism of this protective effect remains unclear. The findings do not support a simple causal relationship between adrenocortical activity and gastric ulceration.

Animals↗
PubMed1989

A modular stopped-flow system for use in routine pharmaceutical analysis.

A modular stopped-flow system for routine pharmaceutical analysis is presented. It consists of an inexpensive stopped-flow module which is fitted to a spectrophotometer or spectrofluorimeter and controlled by a simple computer. The automatic technique developed with this system is suitable for the individual and simultaneous determination of various pharmaceuticals (anti-asthmatics, psychotropics, hormones, analgesics, anaesthetics and antiseptics) with satisfactory results.

Autoanalysis↗
PubMed1986

Rotative agitation RIA. A high sensitivity technique for hepatitis B surface antigen (HBsAg) determinations.

With the objective of finding a simpler and more sensitive method than conventional radioimmunoassay testing to detect HBsAg, we have modified the sample volume and first incubation procedure of the Ausria IIA method. There was an up to 9-fold increase in sensitivity without loss of specificity, in different assays, when the first incubation was carried out with a serum sample of 1 ml that was rotatively agitated for 22 h at room temperature. Additionally, 71 samples from which conventional testing had isolated hepatitis B core antibodies were tested with the modified rotative agitation technique and 9 of these specimens (12.67%) were positive for HBsAg. Routine employment of the rotative agitation radioimmunoassay technique to screen HBsAg by blood banks, to detect potential infectious donations that escape conventional testing, could be an effective as well as low-cost procedure to prevent post-transfusion hepatitis B.

Blood Banks↗