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Biomedical subjects

R Herrera

Publications and source records attributed to R Herrera.

At least 55 records · Page 3Linked to original sources
PubMed1992

[Ovarian cancer (experience with 186 patients)].

An experience with 186 ovarian carcinomas seen at the Oncology Service of The General Hospital of Mexico, between 1981 to 1990 is reported. Fifty patients, (26.9%) were in stage I; 2, (1.0%) were in stage II; 113 in stage III, (60.7%) and 21, (11.2%) were in stage IV. Epidemiological and clinical aspects are reviewed as well as results of treatment. In 137 cases, (73.6%) we have follow up and it was without evidence of disease between 12 and 60 months with a mean of 18 months in 32, (23.3%). This number includes 22 of 26 patients in stage I, (84.6%); 1 of 2 in stage II; 9 of 89, (10.1%) in stage III and 0 of 20 in stage IV. There were not significant differences in prognosis for stage I with the schemes of treatment employed: only surgery, postoperative radiotherapy and postoperative chemotherapy. Patients in stage III evolutioned without evidence of disease when the surgery left residual disease of 2 cms or less for unit: There were 1 of 59 patients treated only with surgery (1.6%); 3 of 15, (20%) treated with radiotherapy to whole abdomen plus over dosage to pelvis and 5 of 15, (33.3%) treated with two agents of chemotherapy. (cyclophosphamide plus adriamycin of cyclophosphamide plus cisplatin). In 3 of 11 stage III patients, (27.2%) with second look surgeries, we found macroscopic residual tumor.

Adult↗
PubMed1990

A direct role for c-fos in AP-1-dependent gene transcription.

Transcription factor activator protein 1 (AP-1) is a protein fraction that contains c-fos, c-jun, and several other related proteins. Although this protein fraction can stimulate transcription in vitro, the relative contributions of c-fos and c-jun to the transcriptional effect of AP-1 are not clear. In order to approach this question, we have overexpressed both proteins using a baculovirus-mediated expression system and defined their DNA-binding and transcriptional enhancement activities in vitro. Gel mobility-shift and DNase 1 footprinting assays showed that c-jun protein specifically binds to DNA through an AP-1 binding site. Under the same conditions, no detectable binding of c-fos protein was observed. However, when the DNA binding assays were performed in the presence of both c-jun and c-fos, a marked increase in the affinity of c-jun for the AP-1 site was observed. An AP-1-dependent transcription assay was used to test the capability of both proteins to stimulate correctly initiated RNA synthesis in vitro. Under our conditions, c-jun protein was capable of stimulating specific RNA transcription in an AP-1 site-dependent manner. In contrast, c-fos protein showed no detectable transcriptional activation by itself. However, a transcription assay carried out in the presence of both c-fos and c-jun proteins showed that the c-fos/c-jun complex was more active as a transcriptional regulator than c-jun protein alone. These experimental results indicate that c-fos and c-jun proteins are required to reconstitute full AP-1-dependent transcriptional activation and directly demonstrate that c-fos is a regulator of gene expression.

Animals↗
PubMed1989

A direct role for C/EBP and the AP-I-binding site in gene expression linked to adipocyte differentiation.

Adipocyte differentiation is accompanied by the transcriptional activation of many new genes, including the gene encoding adipocyte P2 (aP2), an intracellular lipid-binding protein. Using specific deletions and point mutations, we have shown that at least two distinct sequence elements in the aP2 promoter contribute to the expression of the chloramphenicol acetyltransferase gene in chimeric constructions transfected into adipose cells. An AP-I site at -120, shown earlier to bind Jun- and Fos-like proteins, serves as a positive regulator of chloramphenicol acetyltransferase gene expression in adipocytes but is specifically silenced by adjacent upstream sequences in preadipocytes. Sequences upstream of the AP-I site at -140 (termed AE-1) can function as an enhancer in both cell types when linked to a viral promoter but can stimulate expression only in fat cells in the intact aP2 promoter. The AE-1 sequence binds an adipocyte protein identical or very closely related to an enhancer-binding protein (C/EBP) that has been previously implicated in the regulation of several liver-specific genes. A functional role for C/EBP in the regulation of the aP2 gene is indicated by the facts that C/EBP mRNA is induced during adipocyte differentiation and the aP2 promoter is transactivated by cotransfection of a C/EBP expression vector into preadipose cells. These results indicate that sequences that bind C/EBP and the Fos-Jun complex play major roles in the expression of the aP2 gene during adipocyte differentiation and demonstrate that C/EBP can directly regulate cellular gene expression.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1989

[Pre-existing diseases as risk factors and prognosis of genito-urinary infection in pregnancy].

With the intention of reducing the abortion, preterm delivery and perinatal mortality caused by the genito urinary infection (GUI) we attempt to identify the risk factors and with those make a diagnostic test, that permits detection and prediction of GUI during gestation period. Morbidity records that suggests alterations of immune response were studied in a group of 165 pregnant women that presented GUI and were compared with 86 pregnant women without GUI. As risk antecedents, we found: spontaneous abortions of second trimester 42.4% (study group) and 6.9% (control group) (p < 0.01), repeated vaginitis 31.5% and 2.3% (p < 0.01) urinary tract infection (UTI) 29.7% and 6.92% (p < 0.01), preterm deliveries 17.6% and 3.52% (p < 0.01), puerperal infection 9.12% and 0.0% (p < 0.05), familiar diabetes 21.2% and 8.12% (p < 0.05). Psychiatric pathology 12.72 and 3.5% (p < 0.05), typhoid fever 12.1% and 3.5% (p < 0.05) and surgical infections 16.4% and 8.12% (p < 0.1). A score was elaborated assigning 1/2 point to: puerperal infections, familiar diabetes, psychiatric pathology, typhoid fever and surgical infections; 1 point to: abortion, vaginitis, UTI and preterm delivery and 2 points to: repeated abortion, UTI and preterm delivery. Patients were divided in multiparous and primiparas. In multiparous with 1 or more points we found: sensitivity 75.3%, specificity 81%, positive predictive value 89.3%, negative predictive value 60.7% and accuracy 77.1%. In primiparas with 1/2 or more points we found: sensitivity 61.8%, specificity 70.5%, positive predictive value 78.3%, negative predictive value 51.7% and accuracy 65%.

Abortion, Spontaneous↗
PubMed1988

Synthesis, purification, and characterization of the cytoplasmic domain of the human insulin receptor using a baculovirus expression system.

The cytoplasmic domain of the beta subunit of the human insulin receptor has been overexpressed in insect cells using the baculovirus expression system. A recombinant baculovirus (BIR-2) was constructed by inserting the human insulin proreceptor cDNA fragment that encodes the cytoplasmic domain of the receptor into the genome of Autographa californica nuclear polyhedrosis virus adjacent to the strong polyhedrin promoter. Synthesis of the protein (baculovirus insulin receptor kinase (BIRK), Mr 48,000) in BIR-2-infected Spodoptera frugiperda (Sf9) cells was detected 24 h after infection and maximal accumulation (2-3% of the cytosolic protein) was achieved 48-72 h post-infection. The expressed protein is active as a soluble protein tyrosine kinase, both in Sf9 cells and in vitro. Rapid purification to near homogeneity was accomplished by sequential chromatography on Fast-Q-Sepharose and phenyl-Superose with an overall yield of 35% and a specific activity with histone as substrate of 20 nmol/min/mg protein. Autophosphorylation activated the intrinsic kinase activity of BIRK and decreased its mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Using a combination of tryptic digestion and immunoprecipitation with specific antipeptide antisera, it was ascertained that 30-40% of the 32P incorporated into BIRK by autophosphorylation is in the carboxyl-terminal domain (that includes tyrosyl residues 1316 and 1322 of the human proreceptor). Of the remaining radioactivity, 75% is in the amino-terminal domain (that includes tyrosyl residues 953, 960, 972, 999, and 1075) and 25% is in the conserved autophosphorylation domain (including tyrosyl residues 1146, 1150, and 1151). Limited digestion of BIRK with trypsin yielded a fragment, Mr 38,000, that lacks the carboxyl-terminal domain. This fragment exhibits protein tyrosine kinase activity that is stimulated by autophosphorylation. The properties of the soluble, monomeric BIRK are similar to those of the intact, activated, oligomeric insulin receptor kinase with respect to specificity, immunoreactivity, divalent cation requirements, and specific activity. These observations coupled with the ease of producing 0.4 mg of purified enzyme from 100 ml of suspension culture suggest that BIRK will be useful for biochemical and biophysical analysis of the insulin receptor protein tyrosine kinase.

Chromatography↗
PubMed1987

Denture plaque and palatal mucosa in denture stomatitis: scanning electron microscopic and microbiologic study.

Denture plaque is an etiologic factor in denture stomatitis. In this study, denture and mucosa samples from nine patients were examined in the SEM and processed for microbiologic cultures. Denture plaque in patients with denture stomatitis showed a considerable thickness containing cocci, filaments, rods, yeasts, and desquamated epithelial cells. Some microorganisms were revealed in the connective tissue in one patient and phagocytizing polymorphonuclear leukocytes were found in the palatal mucosa of the patients with denture stomatitis.

Bacteria↗
PubMed1987

Regulation of the protein kinase activity of the human insulin receptor.

The insulin receptor is a hormone-dependent protein tyrosine kinase that belongs to the family of tyrosine kinases associated with growth factor receptors and oncogene products. The activity of the insulin receptor kinase is regulated by the phosphorylation state of specific domains of the protein. Phosphorylation of the receptor on tyrosine residues activates its kinase activity whereas phosphorylation on serine and/or threonine residues inhibits it. In this review, we discuss the evidence that supports a role of the kinase activity of the receptor in the molecular mechanism of insulin action.

Enzyme Activation↗
PubMed1987

Placental abnormalities in systemic lupus erythematosus: in situ deposition of antinuclear antibodies.

We studied 5 placentae from patients with systemic lupus erythematosus (SLE) for the presence of immunopathologic changes. We found antinuclear antibodies (ANA) deposited along the villi, trophoblast and amnion producing a lupus band-like pattern. The ANA were IgG class and had C3 fixing activity. Of the T cell subsets found in the placenta, OKT8 was the predominant type in patients with SLE and controls. All the patients were ANA positive, and 1 was also positive for anti-Ro(SSA). One newborn, positive for ANA and anti-Ro(SSA), developed neonatal lupus, 1 infant with a cardiac septal defect was ANA negative, and the other infants were normal. Our study demonstrates that in pregnant women with SLE, ANA deposition occurs in the placenta in situ.

Antibodies, Antinuclear↗
PubMed1986

Autophosphorylation of the insulin receptor in vitro. Designation of phosphorylation sites and correlation with receptor kinase activation.

Chemical degradation and antipeptide antibodies were used to study alterations in the structure and function of the human placental insulin receptor following autophosphorylation in vitro. Antibodies elicited to residues 1143-1162 (P2) of the human insulin proreceptor immunoprecipitated the native, phosphorylated receptor but not the unphosphorylated receptor. Since this antibody recognizes both forms of the receptor on immunoblots, it was concluded that the accessibility of the P2 domain to the antibody is increased by in vitro autophosphorylation. Chemical cleavage at either tryptophan or methionine residues followed by immunoprecipitation with antipeptide antibodies was used to map the in vitro autophosphorylation sites of the beta subunit of the insulin receptor. Two phosphorylated fragments were resolved. One, recognized by antibody elicited to amino acid residues 1328-1343 (P5), is derived from the carboxyl terminus of the beta subunit and includes tyrosine 1316. The other, recognized by antibody to P2, is located in a domain that includes tyrosine 1150. The rate of phosphorylation of this latter site correlates with the rate of activation of the insulin receptor kinase during in vitro autophosphorylation. The results support the following conclusions: autophosphorylation alters the conformation of the beta subunit of the insulin receptor; autophosphorylation in vitro leads to phosphorylation of tyrosine residues near the carboxyl terminus of the protein and in the P2 domain that includes tyrosine 1150; activation of the insulin receptor kinase correlates with autophosphorylation of the domain containing tyrosine 1150.

Adenylyl Imidodiphosphate↗
PubMed1986

Antibodies to deduced sequences of the insulin receptor distinguish conserved and nonconserved regions in the IGF-I receptor.

Antipeptide antibodies directed to two amino acid sequences predicted from the cDNA encoding the insulin proreceptor have been used to study the relationship between the human receptors for insulin and insulin-like growth factor I (IGF-I). An antibody directed to a cytoplasmic domain near the membrane spanning region of the proreceptor inhibited the protein tyrosine kinase activity of both receptors whereas an antibody directed to the C terminus of the insulin receptor showed no cross-reactivity with the IGF-I receptor. The results establish that the cloned cDNA from the human placenta encodes the insulin receptor and not the closely related IGF-I receptor, that the IGF-I and insulin receptors share a specific amino acid sequence necessary for the expression of enzymatic activity, and that the C terminus of the insulin receptor is not conserved in the IGF-I receptor.

Amino Acid Sequence↗
PubMed1986

Isolation of a Drosophila genomic sequence homologous to the kinase domain of the human insulin receptor and detection of the phosphorylated Drosophila receptor with an anti-peptide antibody.

A Drosophila genomic fragment has been isolated with a deduced amino acid sequence that is strikingly homologous to that of the kinase domain of the human insulin receptor. The Drosophila DNA hybridizes with an 11-kilobase mRNA that is most prominent in 8- to 12-hr embryos. An anti-peptide antibody prepared to a sequence in the human insulin receptor kinase domain that is conserved in the Drosophila sequence immunoprecipitates a single 95-kDa Drosophila protein whose phosphorylation on tyrosine residues is dependent on insulin. We conclude that the DNA sequence is that of the kinase domain of the Drosophila insulin receptor and that the 95-kDa phosphoprotein is the autophosphorylated beta subunit of that receptor. The results are compatible with our previous reports demonstrating a specific insulin-binding Drosophila glycoprotein and an insulin-dependent tyrosine protein kinase whose activity is greatest during embryogenesis. The observations suggest a role for insulin-dependent protein tyrosine phosphorylation during embryogenesis.

Amino Acid Sequence↗
PubMed1985

Acquisition of insulin-dependent protein tyrosine kinase activity during Drosophila embryogenesis.

We have previously reported (Petruzzelli, L., Herrera, R., Garcia, R., and Rosen, O. M. (1985) Cancer Cells 3, 115-121) that adult Drosophila melanogaster contain a specific, high-affinity insulin-binding protein. Insulin-dependent protein tyrosine kinase activity has now been identified in Drosophila. Activity first appears at 6-12 h of embryogenesis, increases during the 12-18-h period and falls to low levels in the adult. 125I-insulin was cross-linked specifically and with high affinity to a protein (Mr = 135,000) throughout embryogenesis and in the adult. However, during the 6-12- and 12-18-h periods of embryogenesis when insulin-dependent protein tyrosine kinase activity is expressed, another protein (Mr = 100,000) becomes cross-linked to 125I-insulin. Crosslinking to both proteins was competitively inhibited by the addition of 100 nM insulin. We conclude that the insulin-binding and insulin-dependent protein tyrosine kinase activities of the mammalian insulin receptor are conserved in Drosophila. However, the insulin-dependent protein tyrosine kinase activity of the receptor is detected only during specific times in embryogenesis.

Amino Acids↗
PubMed1985

An antipeptide antibody that specifically inhibits insulin receptor autophosphorylation and protein kinase activity.

Two site-specific antibodies that immunoprecipitate the human insulin receptor have been prepared by immunizing rabbits with chemically synthesized peptides derived from the cDNA-predicted amino acid sequence of the beta subunit of the proreceptor. Antibodies to the carboxyl terminus (AbP5) and to a domain around tyrosine-960 (AbP4) specifically recognize the beta subunit of the receptor on immunoblots. Both antibodies immunoprecipitated 125I-labeled insulin-receptor complexes and the autophosphorylated receptor. Although neither antibody inhibited insulin binding to the receptor, both insulin-dependent autophosphorylation and exogenous substrate phosphorylation were inhibited by AbP4. Inhibition by AbP4 was dependent upon the phosphorylation state of the receptor; it was not detected when the receptor was autophosphorylated prior to addition of AbP4. AbP4 did not inhibit activity of the related epidermal growth factor (EGF)-receptor tyrosine protein kinase nor did it inhibit the activity of cAMP-dependent kinase or protein kinase C. The observation that an antibody directed to residues 952-967 of the proreceptor neutralizes the protein kinase activity of the beta subunit suggests that this region may play a critical role in the function of the hormone-dependent, protein tyrosine-specific kinase activity of the insulin receptor.

Amino Acid Sequence↗
PubMed1985

Dermatomyositis-like syndrome caused by trichinae. Report of two cases.

We report 2 cases of trichinosis in which the clinical features resembled dermatomyositis. In both cases, however, the diagnosis was established histologically by demonstrating trichina larvae in the patients' muscle biopsies. Indirect immunofluorescence and counterimmunoelectrophoresis techniques were used to confirm the diagnosis serologically.

Adult↗