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F Vega

Publications and source records attributed to F Vega.

At least 19 recordsLinked to original sources
PubMed2006

[Light-induced amaurosis fugax].

INTRODUCTION: Internal carotid artery atherosclerotic disease may present with a wide variety of ipsilateral ocular symptoms and signs that can herald a devastating stroke. Asymptomatic retinal emboli, transient monocular visual loss (also known as amaurosis fugax) and central retinal artery occlusion are the most common. CLINICAL CASE: A 66-year-old man presented several spells of monocular light-induced amaurosis fugax related to a severe carotid occlusive disease. Ancillary tests showed an exhausted cerebrovascular reactivity and visual evoked potentials demonstrated an increased latency. Following a carotid endarterectomy the patient remained asymptomatic and ancillary tests normalized. DISCUSSION: Our report supports the theory that light-induced amaurosis fugax occurs on a hemodynamic basis. A prompt recognition of this symptom is critical since symptomatic severe carotid stenosis implies a high risk of ipsilateral stroke.

Aged↗
PubMed2005

Effect of acute sublethal endotoxaemia on in vitro digital vascular reactivity in horses.

Endotoxaemia is a syndrome linked to the development of equine laminitis; however, the relationship between them is uncertain. The aim of this experiment was to evaluate the effect of an experimental acute sublethal endotoxaemia model on in vitro equine palmar digital vascular reactivity. Rings of arteries and veins of each forelimb were obtained from 11 clinically healthy horses submitted to two surgical procedures, 3 weeks apart. Before the second surgery, 0.25 microg/kg of lipopolysaccharide from Escherichia coli O55:B5 in saline, was administered i.v. in 30 min. After 3 h, the vessels were harvested and submitted to in vitro vascular reactivity experiments and histopathology. The response to depolarizing Krebs solution (DKS, 40 mm), phenylephrine (PHE), acetylcholine (ACh) and sodium nitroprusside (SNP) were evaluated. All horses showed colic pain and watery diarrhoea, tachycardia, tachypnea, hyperthermia and leucopenia. Concentration-response curve (CRC) to PHE was shifted to the left in arteries rings from endotoxemic horses without any effect on vein rings. The CRC to ACh was shifted to the right with a reduction in the maximal response. The response to SNP and DKS was similar between groups. There was no evidence of histopathological effects. The increased response to PHE in digital arteries together with a reduction of the endothelium-dependent response to ACh in arteries and veins, confirm the existing reports where endotoxaemia was found to modify the digital vascular reactivity during the acute phase. As the digital endothelial function is impaired, there may be an increased potential to develop a digital prothrombotic state with a reduced vasodilatory capacity.

Acute Disease↗
PubMed2004

Suppressor of cytokine signaling 3 expression in anaplastic large cell lymphoma.

Using a cDNA microarray, we found that suppressor of cytokine signaling 3 (SOCS3) is highly expressed in anaplastic lymphoma kinase (ALK)+ anaplastic large cell lymphoma (ALCL) cell lines. As SOCS3 is induced by activated signal transducer and activator of transcription 3 (STAT3), and ALK activates STAT3, we hypothesized that SOCS3 may play a role in ALK+ ALCL pathogenesis via the Janus kinase 3 (JAK3)-STAT3 pathway. Using ALCL cell lines, we show by coimmunoprecipitation experiments that SOCS3 physically binds with JAK3 in vitro, and that JAK3 inhibition by WHI-P154 downregulates SOCS3 expression. Western blot analysis confirmed expression of SOCS3 and also showed coexpression of phosphorylated (activated) STAT3 (pSTAT3). Direct sequencing of the SOCS3 gene showed no mutations or alternative splicing. In ALCL tumors that were assessed by immunohistochemistry, nine of 12 (75%) ALK+ tumors were SOCS3 positive and eight (67%) coexpressed pSTAT3. In comparison, 18 of 25 (72%) ALK-- tumors were SOCS3 positive and seven (28%) coexpressed pSTAT3. These results show that SOCS3 is overexpressed in ALCL, attributable to JAK3-STAT3 activation and likely related to ALK in ALK+ tumors. However, SOCS3 is also expressed in tumors that lack STAT3 and ALK suggesting alternative mechanisms of upregulation.

Alternative Splicing↗
PubMed2002

Survey of blindness and visual impairment in Bioko, Equatorial Guinea.

AIMS: This study was designed to estimate the prevalence of blindness and its main aetiologies in Bioko, an onchocerciasis endemic zone of Equatorial Guinea. METHODS: Random sampling was applied, proportionally to population distribution into urban or rural areas. All the subjects underwent a basic eye examination by trained nurses. In the presence of any ocular affection or a visual acuity of less than 0.3, the subject was visited by the ophthalmologist. This visit included direct and indirect ophthalmoscopy, anterior segment examination with a slit lamp, and intraocular pressure recording. Blindness and visual impairment were defined by using the WHO criteria. RESULTS: 3218 subjects were screened, with a mean age of 34.1 (SD 21.6) years, ranging from 1 month to 102 years (median 34 years). The overall prevalence of blindness was 3.2% (95% CI: 2.6% to 3.9%). Unilateral blindness was present in 4.2%. Visual impairment was diagnosed in 200 patients (6.8%). More than 20% of the acuities inferior to 0.7 improved when explored with a pinhole. The main causes of blindness were cataracts (61.3%); macular affection (25.3%), optic atrophy (16%), and glaucoma (13.3%). Ocular onchocerciasis was detected in 12 cases (0.4%). CONCLUSION: Ocular onchocerciasis was very uncommon in an area of high endemicity. Results also pointed at the lack of basic ophthalmologist eye care and optician resources in the island.

Adolescent↗
PubMed2001

Immature human dendritic cells express asialoglycoprotein receptor isoforms for efficient receptor-mediated endocytosis.

In a search for genes expressed by dendritic cells (DC), we have cloned cDNAs encoding different forms of an asialoglycoprotein receptor (ASGPR). The DC-ASGPR represents long and short isoforms of human macrophage lectin, a Ca(2+)-dependent type II transmembrane lectin displaying considerable homology with the H1 and H2 subunits of the hepatic ASGPR. Immunoprecipitation from DC using an anti-DC-ASGPR mAb yielded a major 40-kDa protein with an isoelectric point of 8.2. DC-ASGPR mRNA was observed predominantly in immune tissues. Both isoforms were detected in DC and granulocytes, but not in T, B, or NK cells, or monocytes. DC-ASGPR species were restricted to the CD14-derived DC obtained from CD34(+) progenitors, while absent from the CD1a-derived subset. Accordingly, both monocyte-derived DC and tonsillar interstitial-type DC expressed DC-ASGPR protein, while Langerhans-type cells did not. Furthermore, DC-ASGPR is a feature of immaturity, as expression was lost upon CD40 activation. In agreement with the presence of tyrosine-based and dileucine motifs in the intracytoplasmic domain, mAb against DC-ASGPR was rapidly internalized by DC at 37 degrees C. Finally, intracellular DC-ASGPR was localized to early endosomes, suggesting that the receptor recycles to the cell surface following internalization of ligand. Our findings identify DC-ASGPR/human macrophage lectin as a feature of immature DC, and as another lectin important for the specialized Ag-capture function of DC.

Amino Acid Sequence↗
PubMed2001

Marginal-zone B-cell lymphoma of extranodal mucosa-associated lymphoid tissue type: molecular genetics provides new insights into pathogenesis.

Marginal zone B-cell lymphoma of extranodal mucosa-associated lymphoid tissue (MALT) type is recognized as a distinct clinicopathologic entity in the revised European-American lymphoma (REAL) and recently published World Health Organization (WHO) classifications. These neoplasms are thought to arise from the extranodal equivalent of the lymph node marginal zone. Two recurrent chromosomal translocations, to date, have been implicated in the pathogenesis of these neoplasms. The t(11;18)(q21;q21), which is far more common, disrupts the api2 gene on chromosome 11q21 and the malt1 (mlt) gene on chromosome 18q21, resulting in the synthesis of a novel fusion gene and protein, API2-MALT1. The t(1;14)(p22;q32), which is uncommon, juxtaposes the bcl-10 gene on chromosome 1p22 adjacent to the immunoglobulin heavy chain (IgH) gene on chromosome 14, wherein BCL10 is overexpressed via the influence of the IgH enhancer. BCL-10 may then form a complex with MALT1 in the cell. Both translocations result in increased inhibition of apoptosis, conferring a survival advantage. Recent work suggests that API2-MALT1 and BCL-10-MALT1 may activate NF-kB and a common downstream signaling pathway.

Adult↗
PubMed2001

A novel four-color PCR assay to assess T-cell receptor gamma gene rearrangements in lymphoproliferative lesions.

We describe a novel 4-color polymerase chain reaction (PCR) assay combined with GeneScan analysis to assess for T-cell receptor gamma chain gene (TCRgamma) rearrangements and evaluate its usefulness in 86 lymphoproliferative lesions. In this assay, each variable region (Vgamma) family primer is 5' end-labeled with a different fluorescent dye, allowing determination of the Vgamma family involved in each TCRgamma rearrangement. PCR products were analyzed by capillary electrophoresis. We detected clonal TCRgamma rearrangements in 60 (98%) of 61 T-cell lymphomas, 2 (15%) of 13 B-cell lymphomas, and 3 (25%) of 12 reactive lesions. These results compared favorably with conventional PCR methods using denaturing gradient gel electrophoresis, which revealed clonal TCRgamma rearrangements in 37 (90%) of 41 T-cell lymphomas, 1 (25%) of 4 B-cell lymphomas, and 2 (25%) of 8 reactive lesions. This 4-color PCR assay is at least equivalent to conventional PCR methods and is convenient, allows accurate size determination of TCRgamma rearrangements, and identifies the specific Vgamma family involved, providing more specific information about TCRgamma rearrangement.

Gene Rearrangement↗
PubMed2001

Hepatosplenic gamma/delta T-cell lymphoma in bone marrow. A sinusoidal neoplasm with blastic cytologic features.

We report 8 cases of hepatosplenic T-cell lymphoma (HSTCL) involving bone marrow and correlate histologic findings with disease progression. Immunophenotypic analysis demonstrated mature, aberrant gamma/delta T-cell immunophenotypes. Isochromosome 7q was identified in 4 cases; 1 case showed the t(7;14)(q34;q13). Seven of 7 cases tested had monoclonal TCR gamma gene rearrangements. The initial diagnostic bone marrow biopsy specimens were hypercellular with a frequently subtle, predominantly sinusoidal infiltrate of atypical small to medium-sized lymphoid cells. In all cases, aspirate smears at diagnosis and in subsequent specimens contained malignant cells that resembled blasts, some with fine cytoplasmic granules. With progression, the pattern of HSTCL in bone marrow biopsy specimens became increasingly interstitial, and the neoplastic cells became larger. In aspirate smears, the proportion of blasts increased. Seven patients died; 1 was lost to follow-up. Autopsy performed on 1 patient demonstrated malignant cells within vascular channels in all organs sampled, with relatively little tumor formation, resembling intravascular lymphoma at these sites. HSTCL often can be recognized in bone marrow by its unique combination of a sinusoidal pattern in core biopsy specimens and blastic cytology in aspirate smears.

Adolescent↗
PubMed2001

Primary paratesticular lymphoma: a report of 2 cases and review of literature.

Non-Hodgkin lymphoma arising in the paratesticular organs without testicular involvement is rare. In most previously reported cases, the classification systems that were used are now outdated and/or immunologic studies were not done. We report the clinical and pathologic features of 2 cases of non-Hodgkin lymphoma arising in the epididymis and the spermatic cord. Patient 1 was a 35-year-old man who presented with a painless scrotal mass. Patient 2 was a 61-year-old man who presented with a right inguinal mass. Orchiectomy performed in both patients revealed a mass confined to the epididymis in patient 1 and to the spermatic cord in patient 2. Histologic examination in both cases revealed diffuse large cell lymphoma, and immunohistochemical studies supported B-cell lineage. Subsequent staging studies showed no other site of disease in patient 1 and an isolated mass anterior to the right psoas muscle in patient 2. Malignant lymphoma involving testicular adnexal structures without involvement of the testis is extremely uncommon. To our knowledge, only 6 cases confined to the epididymis and 12 cases confined to the spermatic cord have been reported previously.

Adult↗
PubMed2000

Novel p19 protein engages IL-12p40 to form a cytokine, IL-23, with biological activities similar as well as distinct from IL-12.

A novel sequence discovered in a computational screen appears distantly related to the p35 subunit of IL-12. This factor, which we term p19, shows no biological activity by itself; instead, it combines with the p40 subunit of IL-12 to form a novel, biologically active, composite cytokine, which we term IL-23. Activated dendritic cells secrete detectable levels of this complex. IL-23 binds to IL-12R beta 1 but fails to engage IL-12R beta 2; nonetheless, IL-23 activates Stat4 in PHA blast T cells. IL-23 induces strong proliferation of mouse memory (CD4(+)CD45Rb(low)) T cells, a unique activity of IL-23 as IL-12 has no effect on this cell population. Similar to IL-12, human IL-23 stimulates IFN-gamma production and proliferation in PHA blast T cells, as well as in CD45RO (memory) T cells.

Amino Acid Sequence↗
PubMed2000

[Echinococcosis/hydatidosis in the VII Region of Chile: diagnosis and educational intervention].

This study was designed to embrace three areas: a) serologic and radiologic diagnosis and surgical treatment of hydatidosis in an asymptomatic human population, b) animal diagnosis and the treatment of dogs, and c) evaluation of extent of knowledge and performance of educational interventions among rural families and health, livestock, and education professionals and technicians, in order to help control the disease transmission cycle. Indirect hemagglutination and ELISA tests were performed on 5,556 apparently healthy people. Of these, 42 (0.8%) had positive results on both tests, for a seroprevalence of 754.6 per 100,000. These 42 subjects were scheduled for liver ultrasonography and a chest x-ray; of the 26 who complied, 16 showed images compatible with a hydatid cyst. Those 16 cases were sent to the hospital for surgery. In 9 of the cases the diagnosis was confirmed surgically, for a prevalence of 161.7 per 100,000. Arecoline hydrobromide was administered as a laxative to 2,358 dogs to detect the strobilar form of Echinococcus granulosus, and positive results were found in 11% of the dogs. Official data for slaughterhouses indicated the presence of hydatid cysts in 13% of the cattle, 4.4% of the sleep, and 4.2% of the pigs slaughtered in the region. The educational program included an evaluation of the extent of knowledge by surveying heads of household; an educational intervention among families through an informal active participatory process using educational games, in which 1,082 families participated; and an educational intervention with professionals and technicians using distance and in-person approaches. To evaluate the program, the results of knowledge tests before and after educational interventions with 200 families (cases) were compared with those from 95 families who did not participate (controls). Of the 1,423 heads of household initially surveyed about their knowledge of echinococcosis/hydatidosis, 783 of them (55%) said they knew nothing about the infection. It was found that the participatory educational games were well adapted to the lifestyle of people from rural areas and made change possible. Training was provided to 276 health professionals, 201 technical assistants, and 453 rural teachers. The program reached 100% of the staff members of the area's rural primary health care services.

Animals↗
PubMed1999

Utility of immunophenotypic and immunogenotypic analysis in the study of necrotic lymph nodes.

We report a case of complete lymph node necrosis. No specific aetiology could be determined by morphology, but a B lymphoid population and clonal rearrangement of the immunoglobulin heavy chain gene were demonstrated in immunophenotypic and immunogenotypic studies performed using DNA extracted from paraffin embedded necrotic tissue. In the setting of lymph node necrosis, we suggest that immunohistochemical and gene rearrangement studies may provide additional diagnostic information.

Female↗
PubMed1999

Susceptibility to apoptosis measured by MYC, BCL-2, and BAX expression in arterioles and capillaries of adult spontaneously hypertensive rats.

Hypertension results in microvascular rarefaction or disappearance of microvessels. In the present study, we investigated the pathogenic role of apoptosis in hypertension-induced rarefaction of heart arterioles and capillaries of spontaneously hypertensive rats (SHR). Experiments were performed on hearts from 6-week-old, 16-week-old, and 30-week-old SHR (n = 30 rats) (SHR6, SHR16, SHR30). We used as controls 6-week-old, 16-week-old, and 30-week-old normotensive rats (WKY) (n = 30 rats) (WKY6, WKY16, WKY30). We analyzed the expression of c-myc, bcl-2, and bax and in situ end-labeling DNA fragmentation in vascular smooth muscle cells of arterioles and endothelial cells of arterioles and capillaries. Endothelial cells of capillaries and endothelial and smooth muscle cells of arterioles of hypertensive animals (SHR) express more Bax protein and Myc protein than their respective normotensive controls by margins that were statistically significant. The SHR30 group expressed the lowest levels of Bcl-2 protein by a margin that was statistically significantly different from WKY30. We did not find evidence of apoptosis in arterioles or capillaries on the basis of in situ end-labeling. However, our results indicated that alterations in the expression of members of the Bcl-2 family of proteins and Myc protein occurred in smooth muscle cells and endothelial cells of arterioles and capillaries of SHR. In conclusion, although evidence of apoptosis in arterioles and capillaries was not found by in situ end-labeling, our findings suggest that in hypertension they may have a higher susceptibility to apoptosis, and therefore rarefaction may be a consequence of apoptosis.

Animals↗
PubMed1999

Determination of normative criteria and validation of the SKT for use in Spanish-speaking populations.

Most of the tests, questionnaires, and neuropsychological batteries for the assessment of dementia have been translated and adapted for use in the Hispanic population without having normative data, which results in a high number of false positives when age and educational level are not considered. The Short Cognitive Performance Test (SKT) is a psychometric instrument evaluating memory and attention deficits that has been developed and standardized in Germany (Erzigkeit, 1989a, 1989b). The objective of this study was to adapt the SKT, to establish normative criteria that take into consideration age and educational level, and to establish its concurrent validity in comparison to other neuropsychological tests: Brief Neuropsychological Evaluation for Spanish-Speaking Subjects (Ostrosky-Solis et al., 1994), the Mini-Mental State Examination (Folstein et al., 1975), and the Blessed Functional Scale (Blessed et al., 1968) in 238 neurologically intact subjects and 97 subjects with mild to moderate dementia. The SKT showed adequate sensitivity (80.5%) and specificity (80.3%) in subjects with medium and high educational level; however, the sensitivity and specificity diminished (75% and 56.7%) in subjects with no education or low educational level. The adapted and validated version of the SKT in the Mexican population has been shown to be a psychometric instrument that in subjects with medium educational level can detect cognitive alterations and is able to determine the severity of deterioration; however, in subjects with low educational level and severe dementia, the SKT cannot be usefully administered.

Aged↗
PubMed1999

[An alternative method to determine the radiochemical purity of the 99mTC-tetrofosmine preparations].

This paper describes a new quality control method to determine the radiochemical purity (RCP) value of Technetium-99m-Tetrofosmin preparations. The results of this procedure were compared with the results obtained with the method suggested by the manufacturer of the kit (classic method), consisting in thin-layer chromatography involving the use of a single strip of ITLC/SG as the stationary phase, and a acetone:dichlorometane 35:65 (Ac:DCM) solvent mixture as the mobile phase. The method that is proposed in this paper (alternative method) uses the same stationary phase but it is developed in a single solvent, methylethylketone (MEK). This method has the following advantages: a better capacity to separate the 99mTc-Tetrofosmin complex from 99mTcO4- and 99mTcO2 impurities, a faster chromatographic developing time and the use of a single solvent in the quality control.

Acetone↗