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Biomedical subjects

J Gil

Publications and source records attributed to J Gil.

At least 73 records · Page 4Linked to original sources
PubMed2000

Activation of NF-kappa B by the dsRNA-dependent protein kinase, PKR involves the I kappa B kinase complex.

Besides its known role as a translational controlling factor, the double stranded RNA-dependent protein kinase (PKR) is a key transcriptional regulator exerting antiviral and antitumoural activities. We have recently described that induction of NF-kappa B by PKR is involved in apoptosis commitment. To define how PKR mediates NF-kappa B activation by dsRNA, we have used two different approaches, one based on expression of PKR by a vaccinia virus (VV) recombinant and the other based on induction of endogenous PKR by poly I:C (pIC) treatment. We found that NF-kappa B complexes induced by PKR are composed primarily of p50-p65 heterodimers and also of c-rel-p50 heterodimers. As described for other stimuli, following pIC treatment, PKR phosphorylates the NF-kappa B inhibitor I kappa B alpha at serine 32 before degradation. Expression by VV recombinants of IKK1 or IKK2 dominant negative mutants together with PKR showed inhibition of PKR-induced NF-kappa B activation, as measured both by gel shift and luciferase reporter assays. Immunoprecipitation analysis revealed that PKR interacts with the IKK complex. Our findings demonstrate that physiological function(s) of PKR involve activation of the I kappa B kinase complex. Oncogene (2000) 19,1369 - 1378.

Biopolymers↗
PubMed2000

Sonographic diagnosis of a pseudoaneurysm in an intravenous drug abuser.

We report a case of a traumatic pseudoaneurysm and arteriovenous fistula in the groin of a drug abuser. Gray-scale and Doppler sonography were used to establish the diagnosis. Gray-scale sonography revealed an anechoic, ovoid, 7 x 4 cm mass posterior to the right superficial femoral artery, which was displaced anteriorly, with limited visualization of the deep femoral artery. Power Doppler sonography showed complete color filling of the mass, and turbulence was seen on conventional color Doppler sonography. The turbulence was confirmed with pulsed Doppler sonography of the mass. Pulsed Doppler imaging of the right external iliac vein also showed an arterialized spectral flow pattern.

Adult↗
PubMed2000

Maternal cocaine abuse and fetal renal arteries: a morphometric study.

The purpose of the present study was to evaluate the pathological findings and perform morphometric analysis of the renal arteries of fetuses exposed to cocaine in utero. The control group consisted of 22 stillborn fetuses of unknown etiology whose mothers' urine was negative for cocaine or any other vasoactive substances. The study group comprised 29 stillborn fetuses whose mothers' urine was positive only for cocaine on the day of admission. Sections of fetal kidneys (4 microm), stained with hematoxylin and eosin and periodic acid-Schiff reagent, were examined under light microscopy (x40) to identify interlobular arteries. Morphometric analysis of these arteries was performed using a self-assembled system with a touch-sensitive screen as an interactive peripheral. Their inner and outer circumferences were measured by outlining them on the screen with a stylus. The radius (r) was calculated from the measurement of the circumference (2.pi.r). The difference of the radii of the outer and inner circumferences was the thickness of the arterial wall. The interlobular arterial thickness was significantly greater (P<0.001) in the cocaine-exposed group (mean 15.46+/-5.8 microm, 2SD) compared with the normal (mean 9.03+/-3.96 microm, 2SD). There was a significantly (P<0.001) positive relation with advancing gestational ages in both groups. The circumferences of the lumen of the arteries showed a significant (P<0.05) relation with advancing gestational ages in the normal group only. In the cocaine-exposed group, the arterial lumen circumference (mean 167.88+/-17.58 microm, 2SD) was significantly (P<0.001) smaller than in the normal group (mean 227.73+/-6.82 microm, 2SD). Thus, maternal cocaine abuse is associated with thickening of the interlobular arterial wall of the fetal kidney and narrowing of the lumen.

Cocaine↗
PubMed2000

Subcellular ontogeny of brain pyroglutamyl peptidase I.

The present work studies pyroglutamyl-peptidase I activity in several subcellular fractions of the developing brain. In the synaptosomal fraction, soluble pGlu-peptidase I activity is low until postnatal Day 9 (with a peak at postnatal Day 2) and the activity increases at postnatal Day 15. In later stages there are not significant changes of synaptosomal pGlu-peptidase I activity. However, in the cytosolic fraction the activity is high from ED22 until postnatal Day 9, and afterwards decreases. The changes in the particulate fractions are generally less drastic.

2-Naphthylamine↗
PubMed2000

Induction of apoptosis by the dsRNA-dependent protein kinase (PKR): mechanism of action.

Interferons are a family of cytokines that exerts antiviral, antitumor and immunomodulatory actions by inducing a complex set of proteins. One of the best known IFN-induced protein is the dsRNA-dependent protein kinase (PKR), that mediates both antiviral and anticellular activities. PKR inhibits translation initiation through the phosphorylation of the alpha subunit of the initiation factor eIF-2 (eIF-2 alpha) and also controls the activation of several transcription factors such as NF-kappa B, p53, or STATs. In addition, PKR mediates apoptosis induced by many different stimuli, such as treatment with LPS, TNF-alpha, viral infection, or serum starvation. The mechanism of apoptosis induction by PKR involves phosphorylation of eIF-2 alpha and activation of NF-kappa B. In this way, expression of different genes is regulated by PKR. Among the genes upregulated in response to PKR are Fas, Bax and p53. The pathway of PKR-induced apoptosis involves FADD activation of caspase 8 by a mechanism independent of Fas and TNFR. Since IFNs are used as drugs for different disorders such as viral infection and cancer, understanding the pathway of apoptosis induction triggered by PKR should be useful in the rational design of IFN therapies.

Apoptosis↗
PubMed2000

Identification of a new HLA-DRB4 allele (DRB4*01033) by PCR-SSP and direct sequencing.

In this report, we describe the identification of a novel DRB4*01 allele, DRB4*01033, found in two Spanish Caucasian individuals. The new allele was detected during routine HLA typing by an unusual pattern of amplification obtained by polymerase chain reaction using sequence-specific primers (PCR-SSP) that did not match with any of the previously described DRB4 alleles. In order to establish the polymorphism responsible for this pattern exons 2 and 3 of the DRB4 locus were amplified and directly sequenced. The new DRB4*01 allele is identical to DRB4*0103101 except for a single nucleotide substitution in codon 78 (TAC-->TAT). This nucleotide change does not cause an amino acid change as both triplets code for a tyrosine.

Alleles↗
PubMed2000

Prodigiosin from the supernatant of Serratia marcescens induces apoptosis in haematopoietic cancer cell lines.

The effects of supernatant from the bacterial strain Serratia marcescens 2170 (CS-2170) on the viability of different haematopoietic cancer cell lines (Jurkat, NSO, HL-60 and Ramos) and nonmalignant cells (NIH-3T3 and MDCK) was studied. We examined whether this cytotoxic effect was due to apoptosis, and we purified the molecule responsible for this effect and determined its chemical structure. Using an MTT assay we showed a rapid (4 h) decrease in the number of viable cells. This cytotoxic effect was due to apoptosis, according to the fragmentation pattern of DNA, Hoechst 33342 staining and FACS analysis of the phosphatidylserine externalization. This apoptosis was blocked by using the caspase inhibitor Z-VAD.fmk, indicating the involvement of caspases. Prodigiosin is a red pigment produced by various bacteria including S. marcescens. Using mutants of S. marcescens (OF, WF and 933) that do not synthesize prodigiosin, we further showed that prodigiosin is involved in this apoptosis. This evidence was corroborated by spectroscopic analysis of prodigiosin isolated from S. marcescens. These results indicate that prodigiosin, an immunosuppressor, induces apoptosis in haematopoietic cancer cells with no marked toxicity in nonmalignant cells, raising the possibility of its therapeutic use as an antineoplastic drug.

3T3 Cells↗
PubMed2000

Iterative thresholding for segmentation of cells from noisy images.

We introduce an iterative thresholding algorithm for the segmentation of cells from noisy cell images. The thresholding image, which is initially a constant, changes iteratively with both the previous segmentation and image local activity. Experimental results for both synthesized and real cell images are provided to demonstrate the performance of the algorithm.

Algorithms↗
PubMed2000

Subcellular distribution of pyroglutamyl-peptidase I activity in the developing rat cerebellum.

In this work we analyzed the activity of pyroglutamyl (pGlu)-peptidase I in several subcellular fractions of the rat cerebellum during its development. The aim of this study is to determine if there is a developmental redistribution of this enzyme activity and if this fact could indicate changes in the role of the enzyme as age progresses. Results show that pGlu-peptidase I is widely distributed, but not homogeneously, in all the subcellular fractions that were studied, in both soluble and particulate forms. Significantly the distribution of the enzyme changes with development. Thus, in the soluble synaptosomal fraction, the pGlu-peptidase I activity is low until PD9 and the activity increases significantly from PD9 to PD15, when it reaches adult levels. In contrast, in the cytosolic fraction, the pGlu-peptidase I activity is high from fetal day 22 to postnatal day 6, and then decreases significantly until postnatal day 90.

Animals↗
PubMed2000

Morphometric and electron microscopic analyses of the effect of gonadotropin-releasing hormone agonist treatment on arteriole size in uterine leiomyomas.

BACKGROUND: Few studies have been performed on the vascular changes in leiomyomas from patients treated with gonadotropin-releasing hormone agonists (GnRHAs). OBJECTIVE: To measure luminal diameter and wall thickness of arterioles in uterine leiomyomas using a quantitative stereologic method of analysis. DESIGN: Thirty leiomyomas from 3 study groups were used: (1) patients treated with GnRHAs (10 patient samples), (2) age-matched controls (10 patient samples), and (3) postmenopausal women (10 patient samples). Measurements of arteriolar luminal diameter and wall thickness were made using a video-based, computerized system attached to the microscope, for which a morphometric ad hoc program was written. Electron micrographs were made of random arterioles from the first 2 groups (GnRHA-treated patients and age-matched controls). SETTING: Department of Pathology, Mount Sinai School of Medicine, New York, NY. PATIENTS: A total of 30 patient samples were studied, with 3 groups comprising 10 samples each, including patients treated with GnRHAs, age-matched control patients, and postmenopausal women. RESULTS: Arterioles in myomas from patients treated with GnRHAs had slightly larger luminal diameters and significantly thicker walls than age-matched controls and resembled arterioles from postmenopausal women. The thickening was due to smooth muscle cell hyperplasia in the muscularis media. CONCLUSIONS: Treatment with GnRHAs causes a thickening of the walls of intramyomatous arterioles, which resemble those of postmenopausal women. This thickening may play a role in the decreased flow of blood reported in GnRHA treatment.

Adult↗
PubMed2000

Inhibition of cyclooxygenase-2 decreases DNA synthesis induced by platelet-derived growth factor in Swiss 3T3 fibroblasts.

NS-398 [N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide], a selective inhibitor of cyclooxygenase-2 (COX-2), inhibited proliferation induced by platelet-derived growth factor (PDGF) in Swiss 3T3 fibroblasts. The effect of NS-398 was found to be concentration-dependent. The half-maximal effect occurred at approximately 0.1 microM. NS-398 decreased mitogenesis at subsaturating PDGF concentrations and the inhibitory effect of NS-398 was overcome by increasing PDGF concentration. SC-236, another COX-2 selective inhibitor, also inhibited PDGF-induced proliferation. In contrast, two selective COX-1 inhibitors, valeryl salicylate and ketorolac, had no significant inhibitory effect on PDGF-stimulated DNA synthesis. The inhibition was obtained when NS-398 was added during the first hour after PDGF addition. At 1 h, PDGF induced COX-2 protein and prostaglandin (PG)E(2) synthesis, and NS-398 blocked the synthesis of PGE(2). The inhibitory effect of NS-398 on PDGF-stimulated DNA synthesis was counteracted by 280 nM PGE(2). The antimitogenic action of NS-398 and SC-236 suggests that selective inhibition of COX-2 may produce antiproliferative effects with substantial safety advantages over nonselective COX inhibitors.

3T3 Cells↗
PubMed1999

Ontogeny of puromycin-sensitive and insensitive aminopeptidase activities in several subcellular fractions of the rat brain.

Puromycin-sensitive and insensitive aminopeptidase (aminopeptidase M) activities are measured in several subcellular fractions of the rat brain cortex and subcortex during the first postnatal month. Tyr-beta-naphthylamide has been used as substrate and 20 microM puromycin as selective inhibitor. We have found that puromycin-sensitive aminopeptidase activity increases twofold in the synaptosomal and mitochondrial fractions in the first 6-9 postnatal days, just during the period of axonal and dendritic growth. This enzyme also has significant age-related changes in the nuclear fraction. The developmental pattern is different, depending on the subcellular fraction analyzed. Significant developmental changes of puromycin-insensitive aminopeptidase (aminopeptidase M) are only found in the myelinic and microsomal fractions and they are less significant than those found in the puromycin-sensitive aminopeptidase. It has been suggested that these enzyme activities could be involved in processes of cell proliferation, differentiation, and maturation.

Analysis of Variance↗
PubMed1999

In vitro evaluation of fludarabine in combination with cyclophosphamide and/or mitoxantrone in B-cell chronic lymphocytic leukemia.

B-chronic lymphocytic leukemia (B-CLL) is characterized by the accumulation of long-lived CD5(+) B lymphocytes. We have analyzed the effect in vitro of the combination of fludarabine with cyclophosphamide and/or mitoxantrone on cells from 20 B-CLL patients. Mafosfamide, the active form of cyclophosphamide in vitro, increased the cytotoxicity of fludarabine in all of the patients studied and produced a significant synergistic effect (P <.01) after 48 hours of incubation. The addition of mitoxantrone to this combination increased the cytotoxic effect in cells from 8 patients, but in the remaining 12 patients no significant increase was observed. The effect of fludarabine and mafosfamide was dose-dependent. Mafosfamide and fludarabine had a synergistic effect in inducing apoptosis of B-CLL cells as determined by DNA staining with propidium iodide and analysis of phosphatidylserine exposure. Mafosfamide significantly increased the apoptosis induced by fludarabine on CD19(+) cells (P =.007), but not on CD3(+) cells (P =. 314). Cell viability was correlated with a decrease in Mcl-1 levels and an increase in p53 levels. These results support that fludarabine in combination with cyclophosphamide and/or mitoxantrone can be highly effective in the treatment of B-CLL.

Adult↗
PubMed1999

Ovarian dysplasia in prophylactic oophorectomy specimens: cytogenetic and morphometric correlations.

BACKGROUND: Ovarian dysplasia, a potential precursor to ovarian carcinoma, has been described in ovarian tissue obtained by prophylactic oophorectomy and also adjacent to ovarian carcinoma. Women with a family history of ovarian carcinoma, especially those of Jewish Ashkenazi descent, often test positive for BRCA mutant genes. Prophylactically removed ovaries, generally described as normal on macroscopic examination, can exhibit a "preneoplastic phenotype" and unsuspected neoplasm. METHODS: Histologic slides of ovarian tissue from 54 Ashkenazi Jewish women were reviewed. All had a family history of ovarian carcinoma and all were tested for BRCA mutations. Forty-four women tested positive. Thirty-one women underwent prophylactic oophorectomy and 23 underwent oophorectomy for ovarian carcinoma. Normal, dysplastic, and ovarian carcinoma epithelial cells were analyzed morphometrically combining nuclear area measurements with chromatin texture assessment using a novel method based on the computation of autocorrelation coefficients and a derived parameter (Beta). Discriminant analysis between classificatory algorithms was used to obtain results. RESULTS: Ovarian dysplasia was identified in 77.6% of the prophylactic oophorectomy specimens. An unsuspected ovarian carcinoma was diagnosed in one prophylactic oophorectomy specimen. Of 10 women who underwent prophylactic oophorectomy and were negative for BRCA mutations, three had ovarian dysplasia. The average nuclear measurements of the dysplastic cells were similar to those published previously. The new autocorrelation-based method evaluating nuclear texture, as revealed by tridimensional surface plots, demonstrated high discriminatory potential. Discriminant analysis based on nuclear area and nuclear texture information resulted in the correct classification of nearly all the cases in the three diagnostic categories. CONCLUSIONS: Ovaries removed by prophylactic oophorectomy examined in their entirety often reveal ovarian dysplasia and occasionally ovarian carcinoma. The new morphometric method used was highly discriminatory in the evaluation of nuclear texture. Ovarian dysplasia in women with risk factors for ovarian carcinoma is significant in early ovarian carcinogenesis.

Adult↗
PubMed1999

Caspase inhibition protects nigral neurons against 6-OHDA-induced retrograde degeneration.

6-Hydroxydopamine (6-OHDA) administered intrastriatally to adult rats in a single injection causes neurodegeneration of the nigrostriatal pathway and loss of > 50% of dopamine neurons in substantia nigra pars compacta 30 days after administration. The death of nigral neurons occurs, at least partially, by a caspase-mediated mechanism. The nigral loss of dopaminergic neurons could be prevented by stereotaxical administration of zVAD.fmk, a caspase inhibitor, into the substantia nigra, indicating that 6-OHDA-induced nigrostriatal degeneration involves caspase activation. These results suggest that caspases are probably involved in neurodegenerative chronic processes such as Parkinson's disease and might be considered as possible targets in the treatment of such neurological disorders.

Amino Acid Chloromethyl Ketones↗