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Biomedical subjects

F Guerrero

Publications and source records attributed to F Guerrero.

49 records · Page 3Linked to original sources
PubMed1987

GNRH induces activation of Leydig-like cells in Pleurodeles waltlii. A morphometric study.

The ultrastructure of the interstitial cells of the glandular tissue of Pleurodeles waltlii was studied in testis of animals obtained in early breeding season (January) under gonadotropic releasing hormone (GNRH) treatments and controls. These cells (parenchymal or Leydig-like cells) displayed the structural characteristics of steroid-producing cells. GNRH administration for 24 hours induced a significant decrease of both medial volume and volume density of lipid droplets. On the other hand, cell volume, nucleus, mitochondria, mitochondrial cristae and tubules of smooth endoplasmic reticulum were increased. The surface density of mitochondrial cristae was also increased.

Animals↗
PubMed1986

Increased Abscisic Acid Biosynthesis during Plant Dehydration Requires Transcription.

Excised pea plants were rapidly dehydrated to turgor pressures of 1.5 to 2.0 bars. After a 30 minute lag, abscisic acid (ABA) levels increased approximately 100-fold in the dehydrated plants. Pretreatment of plants with the transcription inhibitors actinomycin D or cordycepin or with an inhibitor of cytoplasmic protein synthesis prior to plant dehydration inhibited the synthesis of ABA. These results suggest that dehydration induced synthesis of ABA requires nuclear gene transcription.

Journal Article↗
PubMed1986

Human cellular immune response to copolymer I and myelin basic protein.

Copolymer I (Cop I) is being tested as a treatment for MS because it protects animals against experimental allergic encephalomyelitis, and because there is immunologic cross-reactivity reported between Cop I and myelin basic protein (MBP). From the peripheral blood mononuclear cells of four normal individuals, we isolated helper-phenotype T-cell lines that reacted in vitro with Cop I or MBP. Cop I-reactive cell lines did not respond to MBP, nor did MBP-reactive T-cell lines respond to Cop I. Antigen-specific immune tolerance was induced in MBP-reactive cell lines by exposure to MBP in vitro, but similar exposure to Cop I did not induce tolerance in the MBP-reactive cell lines. We found no evidence of immunologic cross-reactivity between Cop I and MBP.

Animals↗
PubMed1985

Circulating T-cell subsets in Guillain-Barré syndrome.

We compared the distribution of circulating T-cell subsets within 2 weeks of onset of symptoms in 14 patients with acute Guillain-Barré syndrome (GBS) and 37 normal controls. The levels of OKT4+ (putative helper-inducer) cells was definitely abnormal (decreased) in 3/13 tested. The levels of OKT8+ (putative suppressor-cytotoxic) cells were elevated in 3 and decreased in 2 of the 14 tested. Abnormal OKT4/OKT8 ratios were detected in 5 (2 elevated and 3 decreased) patients. Four of the 5 GBS patients with abnormal OKT4+/OKT8+ ratios were studied sequentially at least 4 times over 1-10 months; there was a return towards a normal ratio in all. Serial studies in 3 other GBS patients showed consistently normal values. In comparison, sequential studies over 5-24 months in 7 normals showed no abnormal OKT4+/OKT8+ ratios. Thus, abnormalities in OKT4+/OKT8+ ratios appear to be a marker of systemic events during symptomatic phases of GBS. It is not as yet known whether this is related to the cause or is secondary to the clinical manifestations of GBS.

Antibodies, Monoclonal↗
PubMed1985

Muscle fiber disarray in patients without hypertrophic cardiomyopathy.

Muscle fiber disarray (MFD) has been described as the histologic feature of hypertrophic cardiomyopathy (HC), but it was also found in normal and other abnormal conditions. Its distribution related to the topography of the myocardium has not been described. In this paper, the incidence of MFD in hearts free from HC, the frequency of the histologic disorganization and the affected muscles involved were studied at autopsy. 29 hearts with acute myocardial infarction and 1 with suppurated myocarditis were employed. Macroslides containing the point of maximum septal enlargement were selected for histological examination. The areas of MFD were measured by a polar planimeter and correlated with the involved wall, the total slice area, parietal widths and involved muscles. 27 patients (90%) presented with MFD; hypertrophic ventricular walls were observed in 10, 8 of which had MFD. The remaining 20 patients with nonhypertrophic ventricular walls had MFD in 19 instances. There was septal posterior involvement in 26 cases (p less than 0.0005). 12 patients (44.4%) had only one wall involved. Only 1 patient presented more than 5% of MFD in regard to the total area. The septal wall was the most affected (p less than 0.0005). The most commonly affected muscle was the deep-sinospiral, either alone or combined with other muscles (p less than 0.01). Greater MFD was found (23/30) in patients with septum/posterior wall ratio less than 1.3 cm. It is concluded that MFD may affect up to 10% of the septum in patients free from HC, and that secondary hypertrophy is not a prerequisite for MFD.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1983

Thymic lymphocyte subpopulations in myasthenia gravis.

We compared the percentages of thymic mononuclear cells (TMC) that bind monoclonal antibodies to T-cell subpopulations in patients with myasthenia gravis (MG) and non-MG patients undergoing cardiac surgery (CS). There were no significant differences in percentages of OKT3+, OKT4+, OKT6+, or OKT8+ cells or the OKT4:OKT8 ratio. There was an increase in the percentage of Ia+ (immune response gene-associated antigen) TMC in MG compared with CS but no significant differences in B cells or phagocytic cells. The Ia+ cells could be abnormal B cells, activated T cells, or thymic dendritic cells.

Adult↗
PubMed1982

Oligoclonal IgG in the cerebrospinal fluid of guinea pigs with acute experimental allergic encephalomyelitis.

The cerebrospinal fluid (CSF) of guniea pigs with experimental allergic encephalomyelitis was examined for the presence of oligoclonal IgG using polyacrylamide gel electrophoresis. Oligoclonal IgG (greater than or equal to 2 bands) was seen in the CSF obtained from 3/4 animals with experimental allergic encephalomyelitis induced by myelin basic protein and 2/3 with spinal cord-induced disease. It was not seen in CSF of 3 non-sensitized, 4 adjuvant-sensitized and 7 liver-sensitized guinea pigs. Scanning of stained gels confirmed the oligoclonal pattern. The bands were found in the region of gels which bound [125I]Staphylococcal Protein A. The data demonstrate that a non-infectious inflammatory reaction within the central nervous system can result in an oligoclonal IgG pattern in the CSF.

Animals↗
PubMed1981

The changes in electrical activity of the postural muscles of the mandible upon varying the vertical dimension.

The relation between BT-EMG activity and variations of VD (1 to 41 mm of interocclusal distance) was studied in the masseter, anterior temporal, and posterior temporal muscles of eight normal experimental subjects. EMG activity was recorded with surface electrodes, and the VD was measured with a specially designed device. Recordings were performed with dynamic variations (series A) and with static variations (series B) of VD. Series A shows a gradual decrease of EMG activity starting from the occlusal position, passing through a range of maximum reduction at a certain interocclusal distance, and gradually increasing to the highest values close to maximum jaw opening. Series B shows the same progression, although it points out the exact VD at which minimum basal EMG activity is observed in each muscle studied (10 mm for the masseter muscle, 13 mm for the anterior temporal muscle, and 16 mm for the posterior temporal muscle).

Adult↗
PubMedDate not supplied

[Environment, nutrition and intellectual development].

The differential effects of malnutrition and psychosocial cultural deprivation (PSAC) upon intellectual performance and psychomotor development were studied in 52 preschool children attending nursery schools in urban Santiago (Chile). Nutritional status was evaluated according to Gómez, intellectual performance according to Weschler's scale (WISP and WISC tests), psychomotor development according to the Denver Developmental Screening Test and PSAC according to a numerical scale constructed from maternal I.Q.; socioeconomic status (Graffar) and a psychological questionnaire the correlational analysis, undernutrition was assigned a single value calculated from the severity and duration of the disease. An inverse correlation of - 0.36 existed between malnutrition and intellectual performance, and of - 0.39 between malnutrition and psychomotor development. Also, there was an inverse and significant correlation of - 0.73 between PSAC and psychomotor development; there was no correlation between PSAC and intellectual performance. Verbal I.Q. was more affected (r = - 0.52) than manual I.Q. (r = - 0.18) and children malnourished during the first 6 months of life attained lower scores of I.Q. than normals. The duration of malnutrition (mild in all cases) had no influence upon subsequent I.Q. This study was the basis for a rehabilitation program (educational-nutritional) to be applied in preschool children from nonprivileged areas.

Affective Symptoms↗