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Cole KS, Alvarez M, Elliott DH, Lam H, Martin E, Chau T, Micken K, Rowles JL, Clements JE, Murphey-Corb M, Montelaro RC, Robinson JE. Characterization of neutralization epitopes of simian immunodeficiency virus (SIV) recognized by rhesus monoclonal antibodies derived from monkeys infected with an attenuated SIV strain. Virology 2001; 290:59-73. [PMID: 11883006 DOI: 10.1006/viro.2001.1144] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A major limitation in the simian immunodeficiency virus (SIV) system has been the lack of reagents with which to identify the antigenic determinants that are responsible for eliciting neutralizing antibody responses in macaques infected with attenuated SIV. Most of our information on SIV neutralization determinants has come from studies with murine monoclonal antibodies (MAbs) produced in response to purified or recombinant SIV envelope proteins or intact SIV-infected cells for relatively short periods of time. While these studies provide some basic information on the potential immunogenic determinants of SIV envelope proteins, it is unclear whether these murine MAbs identify epitopes relevant to antibody responses elicited in monkeys during infection with either wild-type or attenuated SIV strains. To accomplish maximum biological relevance, we developed a reliable method for the production of rhesus monoclonal antibodies. In the present study, we report on the production and characterization of a unique panel of monoclonal antibodies derived from four individual monkeys inoculated with SIV/17E-CL as an attenuated virus strain at a time when protective immunity from pathogenic challenge was evident. Results from these studies identified at least nine binding domains on the surface envelope glycoprotein; these included linear determinants in the V1, V2, cysteine loop (analogous to the V3 loop in human immunodeficiency virus type 1), and C5 regions, as well as conformational epitopes represented by antibodies that bind the C-terminal half of gp120 and those sensitive to defined mutations in the V4 region. More importantly, three groups of antibodies that recognize closely related, conformational epitopes exhibited potent neutralizing activity against the vaccine strain. Identification of the epitopes recognized by these neutralizing antibodies will provide insight into the antigenic determinants responsible for eliciting neutralizing antibodies in vivo that can be used in the design of effective vaccine strategies.
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MESH Headings
- Amino Acid Sequence
- Amino Acids
- Animals
- Antibodies, Monoclonal/biosynthesis
- Antibodies, Monoclonal/immunology
- Antibodies, Viral/biosynthesis
- Antibodies, Viral/immunology
- Antigens, Viral/chemistry
- Antigens, Viral/immunology
- Binding Sites
- Binding, Competitive
- CD4 Antigens/immunology
- Cell Line
- Cross Reactions
- Epitopes, B-Lymphocyte/chemistry
- Epitopes, B-Lymphocyte/immunology
- HIV Envelope Protein gp120/chemistry
- HIV Envelope Protein gp120/immunology
- HIV-2/immunology
- Humans
- Macaca mulatta
- Membrane Glycoproteins
- Models, Molecular
- Molecular Sequence Data
- Neutralization Tests
- Peptide Fragments/immunology
- Protein Structure, Secondary
- Sequence Homology, Amino Acid
- Serine Endopeptidases
- Simian Immunodeficiency Virus/immunology
- Simian Immunodeficiency Virus/isolation & purification
- Viral Envelope Proteins
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Puertas A, Paz Carrillo M, Moltó L, Alvarez M, Sedeño S, Miranda JA. Meconium-stained amniotic fluid in labor: a randomized trial of prophylactic amniofusion. Eur J Obstet Gynecol Reprod Biol 2001; 99:33-7. [PMID: 11604183 DOI: 10.1016/s0301-2115(01)00354-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To investigate the effect of amnioinfusion in women with meconium-stained amniotic fluid on the rate of cesarian sections and on neonatal morbidity. STUDY DESIGN A randomized controlled trial. A total of 206 women with meconium-stained amniotic fluid were assigned to receive amnioinfusion via two-way catheter or no amnioinfusion (control group). The catheter was inserted and other treatment was the same in both groups. RESULTS Amnioinfusion decreased the rate of cesarian sections for fetal distress (RR 0.23, 95% CI 0.07-0.79) and increased mean pH at birth (7.24+/-0.1 versus 7.21+/-0.1, P<0.05). It also decreased the frequency of variable fetal heart rate decelerations (RR 0.74, 95% CI 0.59-0.92), and of meconium below the vocal cords in neonates (RR 0.37, 95% CI 0.19-0.69). CONCLUSIONS Amnioinfusion improves the neonatal outcome and reduces the frequency of cesarian sections.
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Greer S, Alvarez M, Mas M, Wozniak C, Arnold D, Knapinska A, Norris C, Burk R, Aller A, Dauphinée M. Five-chlorodeoxycytidine, a tumor-selective enzyme-driven radiosensitizer, effectively controls five advanced human tumors in nude mice. Int J Radiat Oncol Biol Phys 2001; 51:791-806. [PMID: 11697326 DOI: 10.1016/s0360-3016(01)01706-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE The study's goals were as follows: (1) to extend our past findings with rodent tumors to human tumors in nude mice, (2) to determine if the drug protocol could be simplified so that only CldC and one modulator, tetrahydrouridine (H4U), would be sufficient to obtain efficacy, (3) to determine the levels of deoxycytidine kinase and dCMP deaminase in human tumors, compared to adjacent normal tissue, and (4) to determine the effect of CldC on normal tissue radiation damage to the cervical spinal cord of nude mice. METHODS AND MATERIALS The five human tumors used were as follows: prostate tumors, PC-3 and H-1579; glioblastoma, SF-295; breast tumor, GI-101; and lung tumor, H-165. The duration of treatment was 3-5 weeks, with drugs administered on Days 1-4 and radiation on Days 3-5 of each week. The biomodulators of CldC were N-(Phosphonacetyl)-L-aspartate (PALA), an inhibitor of aspartyl transcarbamoylase, 5-fluorodeoxycytidine (FdC), resulting in tumor-directed inhibition of thymidylate synthetase, and H4U, an inhibitor of cytidine deaminase. The total dose of focused irradiation of the tumors was usually 45 Gy in 12 fractions. RESULTS Marked radiosensitization was obtained with CldC and the three modulators. The average days in tumor regrowth delay for X-ray compared to drugs plus X-ray, respectively, were: PC-3 prostate, 42-97; H-1579 prostate, 29-115; glioblastoma, 5-51; breast, 50-80; lung, 32-123. Comparative studies with PC-3 and H-1579 using CldC coadministered with H4U, showed that both PALA and FdC are dispensable, and the protocol can be simplified with equal and possibly heightened efficacy. For example, PC-3 with X-ray and (1) no drugs, (2) CldC plus the three modulators, (3) a high dose of CldC, and (4) escalating doses of CldC resulted in 0/10, 3/9, 5/10, and 6/9 cures, respectively. The tumor regrowth delay data followed a similar pattern. After treating mice only 11/2 weeks with CldC + H4U, 92% of the PC-3 tumor cells were found to possess CldU in their DNA. The great majority of head-and-neck tumors from patient material had markedly higher levels of dC kinase and dCMP deaminase than found in adjacent normal tissue. Physiologic and histologic studies showed that CldC + H4U combined with X-ray, focused on the cervical spinal cord, did not result in damage to that tissue. CONCLUSIONS 5-CldC coadministered with only H4U is an effective radiosensitizer of human tumors. Ninety-two percent of PC-3 tumor cells have been shown to take up ClUra derived from CldC in their DNA after only 11/2 weeks and 2 weeks of bolus i.p. injections. Enzymatic alterations that make tumors successful have been exploited for a therapeutic advantage. The great electronegativity, coupled with the relatively small Van der Waal radius of the Cl atom, may result in CldC's possessing the dual advantageous properties of FdC on one hand and BrdU and IdU on the other hand. These advantages include autoenhancing the incorporation of CldUTP into DNA by not only overrunning but also inhibiting the formation of competing TTP pools in tumors. A clinical trial is about to begin, with head-and-neck tumors as a first target of CldC radiosensitization.
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Alvarez M, Kausel G, Figueroa J, Vera MI. Environmental reprogramming of the expression of protein kinase CK2beta subunit in fish. Mol Cell Biochem 2001; 227:107-12. [PMID: 11827160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
The dramatic segregation of the nucleolar components in winter-acclimatized carp is the most striking cellular-phenotypical feature observed during the seasonal adaptation of this fish toward the circannual changes in its habitat. Our studies also show that the carp habitat temperature and photoperiod winter conditions provoke a remarkable reduction of both rRNA transcription and the processing of their precursors. To gain knowledge on the mechanisms involved in the regulation of nucleolar activity during the seasonal adaptation process, we studied the behavior of some genes, specifically snoRNA U3 and protein kinase CK2. Consistent with the reduction in the synthesis and processing of pre-rRNA observed during the cold season, the level of CK2beta expression decreases in winter when compared to that attained in summer. Similarly, in winter, liver and kidney cells contain lower levels of CK2beta subunit protein compared to summer. CK2 is associated with or modifies different factors and enzymes involved in the nucleolar activity; therefore, its higher or lower content could be part of the molecular mechanisms underlying the nucleolar seasonal changes that occur during the compensatory acclimatization process.
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Brignole M, Menozzi C, Moya A, Garcia-Civera R, Mont L, Alvarez M, Errazquin F, Beiras J, Bottoni N, Donateo P. Mechanism of syncope in patients with bundle branch block and negative electrophysiological test. Circulation 2001; 104:2045-50. [PMID: 11673344 DOI: 10.1161/hc4201.097837] [Citation(s) in RCA: 178] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND In patients with syncope and bundle branch block (BBB), syncope is suspected to be attributable to a paroxysmal atrioventricular (AV) block, but little is known of its mechanism when electrophysiological study is negative. METHODS AND RESULTS We applied an implantable loop recorder in 52 patients with BBB and negative conventional workup. During a follow-up of 3 to 15 months, syncope recurred in 22 patients (42%), the event being documented in 19 patients after a median of 48 days. The most frequent finding, recorded in 17 patients, was one or more prolonged asystolic pause mainly attributable to AV block; the remaining 2 patients had normal sinus rhythm or sinus tachycardia. The onset of the bradycardic episodes was always sudden but was sometimes preceded by ventricular premature beats. The median duration of the arrhythmic event was 47 seconds. An additional 3 patients developed nonsyncopal persistent III-degree AV block, and 2 patients had presyncope attributable to AV block with asystole. No patients suffered injury attributable to syncopal relapse. CONCLUSIONS In patients with BBB and negative electrophysiological study, most syncopal recurrences have a homogeneous mechanism that is characterized by prolonged asystolic pauses, mainly attributable to sudden-onset paroxysmal AV block.
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Mañé J, Fernández-Bañares F, Ojanguren I, Castellá E, Bertrán X, Bartolí R, Alvarez M, Gassull MA. Effect of L-arginine on the course of experimental colitis. Clin Nutr 2001; 20:415-22. [PMID: 11534936 DOI: 10.1054/clnu.2001.0469] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND AND AIMS L-Arg is the substrate for nitric oxide, and also for L-ornithine which, in turn, is the precursor for the synthesis of collagen and polyamines. By these different metabolic pathways, L-Arg is involved in the mechanisms of inflammation, tissue repair and fibrosis. Thus, the aim of this study was to assess the effect of both different amounts of L-Arg supplementation and L-Arg-free diets upon colonic inflammatory damage and fibrosis in experimental colitis. METHODS Sprague-Dawley rats with trinitrobenzene sulphonic acid (TNBS)-induced colitis received increasing doses of L-Arg (30, 100, 500 mg/day), or D-Arg (500 mg/day). In a second experiment, two L-Arg-free diets (one supplemented with L-Gly) were compared to a L-Arg diet. Nitrite/nitrate release in the lumen of the colon and colonic damage were evaluated. In the first experiment, tissue collagen levels and colonic mucosal proliferation were also assessed. RESULTS In the acute phase of colitis, intracolonic nitrite/nitrate levels were significantly higher in the 100 and 500 mg supplemented L-Arg groups than in D-Arg group. However, only rats treated with 500 mg of L-Arg showed moderately higher inflammatory and fibrosis colonic scores than the D-Arg treated rats. There was no significant influence of L-Arg-free diets on the course of TNBS-induced colitis. However, L-Arg diet accelerated weight gain both pre- and post-TNBS. CONCLUSIONS These results suggest that normal amounts of L-Arg in the diet are not harmful, whereas both absence of L-Arg or supplementation with high doses of this amino acid may be deleterious. In the former this might be due to a decrease of nitrogen retention in injured rats, whereas in the latter it may result from both nitric oxide-mediated tissue damage and collagen deposition.
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Bucheli P, Rousseau G, Alvarez M, Laloi M, McCarthy J. Developmental variation of sugars, carboxylic acids, purine alkaloids, fatty acids, and endoproteinase activity during maturation of Theobroma cacao L. seeds. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2001; 49:5046-5051. [PMID: 11600064 DOI: 10.1021/jf010620z] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The changes of mono- and oligosaccharides, carboxylic acids, purine alkaloids, and fatty acid composition, and of aspartic endoproteinase activity, were analyzed during seed development in two varieties of cacao (Theobroma cacao). The majority of the components examined either decreased or accumulated steadily in concentration during the second half of bean development. Sucrose is the major sugar in the mature embryo, whereas fructose and glucose are at higher concentrations in the endosperm tissue. Considerable amounts of malate are found in the endosperm, whereas citrate is the dominant carboxylic acid in the embryo. A major change in the fatty acid composition occurs in the young embryo when the proportion of stearic acid increases rapidly at the expense of linoleic acid, which is reduced from about 18 to 3%. Theobromine is the dominant purine alkaloid (ca. 80%), and caffeine appears only toward the end of seed maturity. Aspartic endoproteinase activity increases rapidly during embryo expansion, reaching a maximal activity before final maturity. The results are discussed in conjunction with physiological changes in developing seeds, and the potential contributions of the compounds analyzed for cocoa quality.
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Santos C, Muñoz N, Klug S, Almonte M, Guerrero I, Alvarez M, Velarde C, Galdos O, Castillo M, Walboomers J, Meijer C, Caceres E. HPV types and cofactors causing cervical cancer in Peru. Br J Cancer 2001; 85:966-71. [PMID: 11592767 PMCID: PMC2375092 DOI: 10.1054/bjoc.2001.1948] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2001] [Revised: 06/01/2001] [Accepted: 06/05/2001] [Indexed: 11/23/2022] Open
Abstract
We conducted a hospital-based case-control study in Peru of 198 women with histologically confirmed cervical cancer (173 squamous cell carcinomas and 25 cases of adenocarcinoma/adenosquamous carcinoma) and 196 control women. Information on risk factors was obtained by personal interview. Using PCR-based assays on exfoliated cervical cells and biopsy specimens, HPV DNA was detected in 95.3% of women with squamous cell carcinoma and in 92.0% of women with adenocarcinoma/adenosquamous carcinoma compared with 17.7% in control women. The age-adjusted odds ratio was 116.0 (95% Cl = 48.6-276.0) for squamous cell carcinoma and 51.4 (95% Cl = 11.4-232.0) for adenocarcinoma/adenosquamous carcinoma. The commonest types in women with cervical cancer were HPV 16, 18, 31, 52 and 35. The association with the various HPV types was equally strong for the two most common types (HPV 16 and 18) as for the other less common types. In addition to HPV, long-term use of oral contraceptives and smoking were associated with an increased risk. HPV is the main cause of both squamous cell carcinoma and adenocarcinoma in Peruvian women.
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Basterra G, Casi MA, Alcorta P, Díaz de Otazu R, Alvarez M, García Campos F. Is carbohydrates-deficient transferrin the best test of the alcoholic etiology in acute pancreatitis? REVISTA ESPANOLA DE ENFERMEDADES DIGESTIVAS : ORGANO OFICIAL DE LA SOCIEDAD ESPANOLA DE PATOLOGIA DIGESTIVA 2001; 93:529-34. [PMID: 11692782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
AIM To demonstrate if carbohydrates deficient transferrin (CDT) is the best marker to detect an excessive alcohol consumption as a cause of acute pancreatitis. MATERIAL AND METHODS Prospective study of 60 patients consecutively admitted in our hospital. Acute pancreatitis were classified according to their different etiologies, alcoholic (11), probably alcoholic (4), biliary (25) and others (20). In all cases, we have compared CDT with classical quemical markers of alcohol abuse such as mean corpuscular volumen (MCV), gamma-glutamyltransferase (GGT) and aspartateaminotransferase (AST). Statistic correlations were done between the quantity of alcohol consumed and CDT, GGT, AST and MCV variables. RESULTS Correlation between CDT and MCV with the excessive alcohol consumption was statistically significant. The acute pancreatitis caused by alcohol and the suspicious alcoholic group had a average CDT higher than the rest of the groups (p < 0.05). Taking a cut point with a CDT value of 20, the diagnosis capacity of the test to detect the alcoholic etiology was 82 and 92% of specificity. Taking a cut point with a MCV value higher than 95, sensibility was 67% and specificity was 82%. CONCLUSION In our experience, the most efficient marker of the alcoholic etiology in acute pancreatitis was CDT.
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Whyte JO, Cisneros AI, Alvarez M, Alconchel MD, Yus C, Torres A, Sarrat R. Contributions to the study of the foetal development of physiological intimal thickening in the human uterine artery. Folia Morphol (Warsz) 2001; 60:199-204. [PMID: 11552660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The morphological study of the development of "intimal thickenings" of the human uterine artery in physiological condition was performed on 72 uterine arteries obtained from foetuses from the 12th week of gestation up to birth. Our results indicate that intimal thickening is formed by the migration and displacement of mesenchymal cells around the site of origin of collateral vessel from uterine mesothelium. These cells firstly differentiate into the myoblasts and then into the myocites. During the development the internal limitans membrane separates the intimal thickening from the tunica media and the elastic fibres appearing inside possessing a muscle-elastic nature. The function of intimal thickenings is the regulation of local blood flow by means of the control of myocitic contractile capacity; these cells play a fundamental role in endothelium-intimal smooth muscle cell contact.
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Lago PM, Guzmán MG, Sarmiento L, Pérez AB, Alvarez M, Capó V, Avalos I, Flores GK. Mechanism of enterovirus involvement in epidemic neuropathy: hypothesis regarding pathophysiology. Med Hypotheses 2001; 56:339-47. [PMID: 11359357 DOI: 10.1054/mehy.2000.1222] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
During the epidemic of optic and peripheral neuropathy which occurred in Cuba in 1992-1993, viruses antigenically related to the Coxsackie viruses were isolated from cerebrospinal fluid of patients. Concurrently with the virologic studies, epidemiologic, toxicologic, nutritional, immunologic, and histopathologic investigations were also carried out. Although it was demonstrated that the illness was associated with toxic and nutritional risk factors, it has not been possible to identify a specific etiology for the symptoms observed. Taking into consideration the results obtained in all of the various investigations, we have formulated an integral, multifactorial hypothesis which attempts to explain a pathophysiologic mechanism by which the viruses isolated could participate in the pathogenesis of the illness. We propose that the viral agents produce a persistent infection, and the possibility that they may act as mediator of an autoimmune pathogenic process.
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Cabrita E, Martínez F, Alvarez M, Herráez MP. The use of flow cytometry to assess membrane stability in fresh and cryopreserved trout spermatozoa. CRYO LETTERS 2001; 22:263-72. [PMID: 11788867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
In this approach flow cytometry combined with PI was used as an alternative method to determined cell membrane integrity and osmotic fragility in trout spermatozoa. Milt was diluted 1:3 in a extender containing either 7% Me(2)SO or 7% Me(2)SO plus egg yolk-BSA and frozen in 0.5 ml French straws on a rack that floated 2 cm over the surface of liquid nitrogen. Cell integrity and membrane resistance to hyposmotic shock was analyzed before and after freezing/thawing. To test cell resistance to hyposmotic shock, sperm was subjected to hypo- and isosmotic solutions (10, 100, 300 mOsm/Kg) and cell integrity was analyzed through a time course (30 sec, 2, 5, 10 and 15 min) using propidium iodide and flow cytometry. This procedure allowed a rapid and accurate identification of different cell subpopulations according to their resistance to hyposmotic shock and, in this way, provides a method to evaluate the sub-lethal damage caused by cryopreservation. The proportion of extremely sensitive cells in fresh spermatozoa (2%) increased after cryopreservation: 30% without stabilizers, and 19% after the addition of egg yolk-BSA, demonstrating that external cryoprotectants significantly improved the resistance to the osmotic stress.
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Alvarez M, Guzmán MG, Pupo M, Morier L, Bravo J, Rodriguez R. Study of biologic attributes of Cuban dengue 2 virus after serial passage in primary dog kidney cells. Int J Infect Dis 2001; 5:35-9. [PMID: 11285157 DOI: 10.1016/s1201-9712(01)90046-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
OBJECTIVE The serial passage of dengue viruses in primary dog kidney (PDK) cells has resulted in selection of attenuated viruses. However, the molecular changes responsible for loss of virulence are not well characterized. This article describes the isolation and biologic attributes of one dengue 2 virulent strain as a first step to allow the study of determinants of virulence at the molecular level. METHODS A15 dengue 2 Cuban strain was isolated from the viremic plasma of a patient with uncomplicated dengue fever during the 1981 epidemic. This was then subjected to serial passage in PDK cells. Viruses resulting from several PDK passages were compared to the parent strain for plaque size and temperature sensitivity, neurovirulence in newborn mice, and cytopathogenic effects on LLC-MK(2) and C6/36-HT cell lines. RESULTS A15 dengue 2 Cuban strain was successfully propagated in PDK cells. Primary dog kidney 52 to 53 viruses exhibited several biologic attributes, such as small plaques, temperature sensitivity, reduced mouse neurovirulence, and cytopathic effect in permissive cell lines. CONCLUSIONS These results represent the first step to allow attenuation of this strain of dengue 2 virus.
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Prieto AS, Ruiz LJ, García N, Alvarez M. [Mollusc diversity in an Arca zebra (Mollusca: Bivalvia) community, Chacopata, Sucre, Venezuela]. REV BIOL TROP 2001; 49:591-8. [PMID: 11935909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
The diversity of a subtidal epifaunal mollusk community was studied from September, 1990 to September, 1991 in Chacopata, Sucre State, Venezuela. There were 40 species (24 bivalves and 16 gastropods). The diversity indexes (H' = 2.087, J' = 0.392, 1/D = 0.528) were low when compared with other tropical zones. Monthly diversity reached its maximum in September, 1990 (1.63 bits/ind.) and July, 1991 (1.60 bits/ind.); minimum diversity occurred in June, 1991 (0.52 bits/ind.). A Log series model applied to species abundance data showed a straight line with a diversity index alpha of 5.56. Of 40 species identified, the turkeywing Arca zebra was dominant (69% in number of individuals and 72% of biomass) followed by Pinctada imbricata, Modiolus squamosus, Chama macerophyla and Anadara notabilis. The predatory snails Phyllonotus pomum, Chicoreus brevifrons and Murex recurvirostris seemed to have trophic relationships with A. zebra. The total mean biomass in wet weight (469.20 +/- 263 g m-2, shell included) was high which indicates that A. zebra, a species with a rapid growth rate, occupies a central role in the assemblage as an efficient filter feeder that converts planktonic food into available biomass, supporting one of the most important fisheries in Venezuela.
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Alvarez M, González R, Briceño I, Cofre C, Labarca J, Vial P, García P. [Diagnosis of Clostridium difficile diarrhea: in search of a more efficient clinical focus]. Rev Med Chil 2001; 129:620-5. [PMID: 11510201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
BACKGROUND The clinical parameters for the suspicion of Clostridium difficile infections, namely the use of antimicrobials and diarrhea, have a low predictive value for the diagnosis. AIM To search other clinical variables and determine a clinical prediction model for (Clostridium difficile diarrhea. PATIENTS AND METHODS All patients to whom a Clostridium difficile study was requested, were prospectively studied during 5 months. Clinical variables of these patients were registered. The diagnosis of Clostridium difficile was done using the cytotoxicity test in fibroblast cultures. RESULTS Ninety two patients were analyzed and in 26, the diagnosis of Clostridium difficile was confirmed. A logistic regression model disclosed an age over 60 years old, the presence of mucus in the stools and a temperature over 37.8 degrees C in the previous 24 h, as significant predictors of the infection. The correlation of the model, between the predicted probability and the observed condition, was 81.5%. CONCLUSIONS The presence of the clinical variables identified in this study are associated with a high probability of an infection by Clostridium difficile in patients with diarrhea and the recent use of antimicrobials.
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Gorordo I, Esteban C, Alvarez M. [Hemorrhagic pleural effusion: atypical presentation of a pleural fibrous tumor]. Arch Bronconeumol 2001; 37:327. [PMID: 11412534 DOI: 10.1016/s0300-2896(01)75080-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Martinez-Vazquez C, Potel C, Angulo M, Gonzalez-Carreró J, Alvarez M, Tenorio A, Cid D, Oliveira I. Nosocomial Kikuchi's disease--a search for herpesvirus sequences in lymph node tissues using PCR. Infection 2001; 29:143-7. [PMID: 11440384 DOI: 10.1007/s15010-001-1122-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Histiocytic necrotizing lymphadenitis, also known as Kikuchi's disease (KD), is a rare disease. Fever and lymphadenopathies with characteristic pathologic features are present. The etiology of this disease remains undetermined. Since the disorder is self-limiting, different viruses have been implicated as the causative agent. PATIENTS AND METHODS Seven cases of KD were studied. Three patients acquired the disease nosocomially, three had community-acquired KD and one case was associated with systemic lupus erythematosus. PCR was performed on DNA extracted from lymph node tissues in order to detect herpesvirus-specific DNA sequences: herpes simpLex virus type 1 and 2 (HSV1-2), varicella zoster virus (VZV), human cytomegalovirus (HCMV), human herpesvirus 6 (HHV6), Epstein-Barr virus (EBV) and human herpesvirus 8 (HHV8). RESULTS Viral DNA was not detected in any of the lymph node tissues from the seven cases of KD. CONCLUSION We conclude that these herpesviruses were not involved in the etiology of the three cases of nosocomial KD, nor in the other four cases of KD investigated in this study.
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Pacheco-Ojeda LA, Martínez AL, Alvarez M. Anaplastic thyroid carcinoma in ecuador: analysis of prognostic factors. Int Surg 2001; 86:117-21. [PMID: 11918236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
The highest incidence of anaplastic thyroid carcinoma (ATC) has been reported in countries with endemic goiter, such as in Ecuador. In this country, ATC is the third most common histologic type of thyroid cancer, following papillary and follicular carcinoma. The aim of this study was to review the clinical presentation and the results of treatment of a large consecutive series of ATC patients treated at the oncological department of a general hospital in Quito, Ecuador. This is a retrospective study of 30 patients diagnosed with ATC at the Social Security Hospital, from 1982 to 1998. Symptomatic rapidly growing neck masses were generally present. All the patients had histological diagnosis of ATC. Two patients with pulmonary metastases and pleural effusion died before treatment could be instituted. Twenty-eight patients received at least one type of treatment: surgery, radiation therapy (RT), or chemotherapy (CT). The two most frequently employed therapeutic modalities were surgery followed by RT and/or CT in 14 patients and surgery alone in 9 patients. Surgery was performed in 23 patients but a complete resection was possible in only 14 patients. RT, postoperatively or alone, was given to 17 patients. Only 5 patients received doses ranging from 4,000 to 5,000 cGy and 4 patients more than 5,000 cGy. CT was administered to 17 patients. Doxorubicin alone was given to 10 patients and different combinations to the remaining patients. Local control was obtained in 8 of 14 complete resections. The prognostic value of the following parameters was studied by univariate analysis: duration of symptoms, size of the tumor, extent of glandular involvement, type of treatment, and surgical margins. A statistically longer survival was found in cases of differentiated carcinoma with areas of ATC or tumor limited to one lobe, those patients who received a complete treatment of chemotherapy, and those patients with tumors smaller than 10 cm and with duration of symptoms longer than 4 months. Longer mean survivals were seen in patients with longer duration of symptoms and smaller lesions. Five patients with focal anaplastic lesions within a differentiated thyroid carcinoma or a lesion limited to one lobe had a significant better survival (a mean of 20 months).
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Gascón J, Alvarez M, Eugènia Valls M, Maria Bordas J, Teresa Jiménez De Anta M, Corachán M. [Cyclosporiasis: a clinical and epidemiological study in travellers with imported Cyclospora cayetanensis infection]. Med Clin (Barc) 2001; 116:461-4. [PMID: 11333706 DOI: 10.1016/s0025-7753(01)71870-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND To assess the clinical and epidemiological characteristics of the enteritis produced by Cyclospora cayetanensis. PATIENTS AND METHOD A microbiological, epidemiological and clinical protocol in travelers to tropical and temperate areas affected by travelers diarrhea (TD). RESULTS C. cayetanenesis was isolated from 55 patients. 96% of them suffered TD. Persistent diarrhea (> 2 weeks) was present in 69% and weight loss > or = 3 kg in 38%. In 36% of cases, TD began after returning from the trip. Although C. cayetanensis has a cosmopolitan distribution, it was mostly isolated from travellers to Latin America, the Indian subcontinent and South East Asia. In only five cases a potential risk factor was detected: strawberries (3), buffalo's milk (1) and marinated fish "ceviche" (1). CONCLUSIONS C. cayetanensis is an emerging enteropathogen, isolated in 2-4% of Spanish travellers suffering from TD, and should be considered in the diferential diagnosis of this clinical entity.
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de Paz P, Sánchez AJ, De la Fuente J, Chamorro CA, Alvarez M, Anel E, Anel L. Ultrastructural and cytochemical comparison between calf and cow oocytes. Theriogenology 2001; 55:1107-16. [PMID: 11322238 DOI: 10.1016/s0093-691x(01)00470-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The use of prepubertal females (calves) to obtain oocytes for in vitro fertilization (IVF) programs, is being analyzed currently. This will increase the availability of female oocytes and will allow a reduction of the interval between generations. Differentials in the development capability of calf and cow oocytes have been assessed by different authors, establishing several ultrastructural and metabolic differences between them. This paper analyzes the morphometric and cytochemical differences between calf and cow oocytes through microscopic techniques. The oocytes morphologically classified as good are processed for electron microscopy a) in Epon 812 epoxy resin for morphometric analysis or b) in low temperature Lowycril K4M resin for cytochemical evaluation using Con A, GS, LPA, UEA, and WGA lectins marked with colloidal gold as probes. Calf oocytes show a greater density of microvilli on their surface and a greater number of endocytosic vesicles than those of the cow. On the other hand, cow oocytes show a larger superior mitochondrial population. In the cumulus cells it can be seen that calf oocytes have a greater volume of lipid droplets. Cytochemical analysis shows that calf oocytes have lectin marking restricted to the plasmic membrane, highlighting the presence of LPA. In cow oocytes, lectin marking can be seen both on the plasmic membrane and in the vacuoles, in both cases, with the LPA highlighted. In the zona pellucida of calf and cow oocytes, the same sugars appear (GS, LPA, WGA), and marking with LPA is more extensive in cow oocytes.
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272
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Mallimaci MC, Sijvarger C, Dates A, Alvarez M, Sosa-Estani S. Seroprevalencia de la enfermedad de Chagas en Ushuaia, Argentina, una zona sin triatominos. Rev Panam Salud Publica 2001; 9:169-71. [PMID: 11349352 DOI: 10.1590/s1020-49892001000300006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE Determine the seroprevalence of Trypanosoma cruzi infection in Ushuaia, Argentina, which is the southernmost city in the world. METHODS Serum samples were analyzed from 2,991 people, obtained between January 1995 and December 1996. The samples were processed using indirect hemagglutination and either enzyme-linked immunosorbent assay or indirect immunofluorescence. RESULTS The general seroprevalence of T. cruzi infection was 6.8%. According to the residents' country of origin, prevalence was 41.1% among Bolivians, 5.0% among Argentines, and 0.9% among Chileans. The prevalence found in pregnant women was 5.9%; in compulsory examinations (such as for a job or for immigrants settling permanently in Argentina), it was 6.3%; and in examinations done based on clinical or epidemiological reasons to suspect infection with Chagas' disease, it was 30.8%. CONCLUSIONS There is an alarming level of T. cruzi infection in this region, where the insect vector does not even exist. Given the risk of transmission congenitally and from blood transfusions, controls must be maintained on donated blood. In addition, follow-up of children of infected women should be strengthened so that these children receive early diagnosis and timely treatment of the infection.
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García F, García F, Roldán C, López I, Martínez NM, Alvarez M, Bernal MC, Hernández J, Maroto MC. Detection of HCV and GBV-CHGV RNA in peripheral blood mononuclear cells of patients with chronic type C hepatitis. MICROBIOS 2001; 103:7-15. [PMID: 11034441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Hepatitis C virus (HCV) and hepatitis G virus (HGV) viraemia were investigated by RT-PCR protocols in peripheral blood mononuclear cells (PBMC) of 22 patients with chronic type C hepatitis. Samplings were at basal and 4-8 months after a 12 month period of treatment with interferon-alpha. A plus strand of HCV in PBMC was detected in 8 of 21 patients (38%) (p <0.05; chi2 test) with a lack of response to therapy; a minus strand was detected in 10% of chronic type C hepatitis and 25% of the patients harboured HCV RNA in PBMC. The association with a response was nearly significant (p <0.1; chi2 test). GBV-C/HGV RNA was detected in the serum of 9 of 21 (43%) patients and in PBMC of 20% of the patients viraemic. Genomic sequences of GBVC/HGV in PBMC were found, but further investigation is needed to assess the findings reported for HCV.
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Rivera-Brown AM, Alvarez M, Rodríguez-Santana JR, Benetti PJ. Anaerobic power and achievement of VO2 plateau in pre-pubertal boys. Int J Sports Med 2001; 22:111-5. [PMID: 11281612 DOI: 10.1055/s-2001-11338] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A low anaerobic power has been proposed as a factor that may be limiting the achievement of a plateau in VO2 of children who perform maximal aerobic power tests. This study examined the frequency of plateau achievement in pre-pubertal children and compared VO2max, peak (PP) and mean (MP) anaerobic power in subjects who either achieved a plateau (PLAT) or did not (NO PLAT). Eighteen healthy pre-pubertal (Tanner Stage, pubic hair = 1) males (age = 9.1 1.6 yrs, ht = 134.4 +/- 9.7cm, wt = 33.3 +/- 9.2kg, VO2max = 40.0 +/- 6.7 ml x kg(-1) min(-1)) were tested. All subjects completed a 30 sec Wingate Anaerobic Test and a McMaster aerobic protocol to volitional fatigue on a cycle ergometer. Only 33% of the subjects met the PLAT criterion. No differences were found for PP or MP between those who achieved a plateau and those who did not (PLAT: PP= 6.3 +/- 0.8W/kg and MP = 5.2 +/- 0.7W/kg; NO PLAT: PP= 6.3 +/- 1.2 W/kg and MP = 5.2 +/- 1.3 W/kg). We conclude that anaerobic power is not a factor limiting the achievement of a plateau in VO2 of pre-pubertal boys who perform maximal aerobic power tests.
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Hernández RH, Armas-Hernández MJ, Chourio JA, Armas-Padilla MC, López L, Alvarez M, Pacheco B. Comparative effects of amlodipine and nifedipine GITS during treatment and after missing two doses. Blood Press Monit 2001; 6:47-57. [PMID: 11248761 DOI: 10.1097/00126097-200102000-00008] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To compare the antihypertensive efficacy of amlodipine and nifedipine gastrointestinal therapeutic system (GITS) measured by office and ambulatory blood pressure monitoring (ABPM) during treatment and, after patients have missed two doses. METHOD After a single blind run-in 4-week placebo period, 58 patients were randomly allocated to amlodipine (5mg/daily, n=30) or nifedipine GITS (30mg/daily; n=28) in a double-blind, double dummy fashion. Patients received active medication for 4 weeks. Then, to simulate failure of compliance, patients received two single blinded doses of placebo. Ambulatory blood pressure monitoring was carried out at the end of run-in placebo phase, the first day, the last day of active treatment and up to 72h after the last active dose. RESULTS Diastolic blood pressure was controlled in 61.9% patients on amlodipine and 52.9% on nifedipine GITS. Reductions in blood pressure were similar in both groups. ABPM showed significant reduction in blood pressure from the first day in the nifedipine GITS group, while amlodipine group had marginal effect. Peak reduction in systolic/diastolic blood pressure was 26/15mmHg at 5-6h after ingestion of amlodipine tablets. The trough reduction was 22/13mmHg; with a trough-to-peak ratio of 84.61% for systolic and 86.67% for diastolic blood pressure. Peak reduction in systolic/diastolic blood pressure with nifedipine GITS was 19/15mmHg and the trough reduction was 21/17mmHg, giving a trough-to-peak ratio of 100% for both systolic and diastolic blood pressure. When patients received placebo after 4 weeks of active treatment, simulating a compliance failure, amlodipine maintained reduction in systolic and diastolic blood pressure for at least up to 72h after the last active dose, maintaining 57.71% of the effect for systolic blood pressure and 60.00% for diastolic blood pressure. In contrast, nifedipine GITS effect was rapidly lost during this study phase, with a reduction in systolic and diastolic blood pressure of only 14-16%, 72h after the last active dose. CONCLUSION This study showed that amlodipine and nifedipine GITS reduce blood pressure to about the same extent during chronic treatment. In the case of compliance failure, such as missing one or two doses, amlodipine maintained significant and important antihypertensive effect with the trough-to-peak ratio still over 50% 72h after the last active dose. On the other hand, the coverage of nifedipine GITS was limited to about 36h after the last active dose.
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