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1.
J Biol Regul Homeost Agents ; 27(3): 791-804, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24152844

RESUMEN

Taking into account the mechanisms at the origin of the airways inflammatory pathologies, our attention has been recently addressed to the study of HMGB1, a protein belonging to the group of alarmins. Alarmins are those molecules which in homeostatic conditions carry out specific metabolic and/or structural functions; furthermore, after a direct trauma or an infection, these molecules are released in the extracellular milieu becoming there activators of the innate immunity and powerful inflammatory factors. In a previous research we found in patients affected with chronic rhinosinusitis with/without nasal polyposis (CRSwNP) an increased expression of this protein in the nucleus of nasal mucosa epithelial cells. HMGB1 was overexpressed also as focal subepithelial infiltration and in the inflammatory cells of patients in comparison with controls. These results suggested a possible pathogenetic role of HMGB1 in CRSwNP. The aim of the present study was to investigate if the expression and localization (nuclear, cytoplasmic and extracellular) of the HMGB1 protein-cytokine is somehow related to the severity and complexity of the histological and clinical picture. We noticed values which have around statistical significance between nuclear HMGB1 and eosinophils infiltrate (p=0.0607) and between nuclear HMGB1 and inflammatory infiltrate (P=0.0524). Even more significant was the correlation between extra-cellular HMGB1 expression and the presence of allergic-hyper reactive conditions such as asthma, allergic rhinitis, NSADs intolerance, antibiotic allergy. HMGB1 was significantly more expressed in the nucleus (p=0.0499) and in the intercellular space (p=0.0380) in allergic patients than in non-allergic subjects and as extra-cellular infiltrate in patients with NSADs intolerance (p=0.0022). These results confirm the role of HMGB1 in the pathogenesis of chronic rhinosinusitis with/without nasal polyposis; besides the higher extra-cellular expression in patients with a more severe clinical and inflammatory picture and the presence of associated co-morbidities suggests to seek for new compounds: these compounds, decreasing the extra-cellular release of this alarmin through a scavenger mechanism, could keep under control the inflammatory process without interfering with the nuclear transcriptional messengers.


Asunto(s)
Proteína HMGB1/fisiología , Pólipos Nasales/etiología , Sinusitis/etiología , Adolescente , Adulto , Anciano , Asma/etiología , Biomarcadores , Enfermedad Crónica , Femenino , Proteína HMGB1/análisis , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Pólipos Nasales/patología , Rinitis Alérgica , Rinitis Alérgica Perenne/etiología , Sinusitis/patología
2.
Bull Soc Pathol Exot ; 113(4): 228-239, 2020.
Artículo en Francés | MEDLINE | ID: mdl-33826274

RESUMEN

The article focuses on describing the different causal models of misfortune and their social constructions in the context of the Ebola virus disease which emerged in Equateur Province, Democratic Republic of Congo, in May 2018. Based on a corpus of qualitative data collected during three weeks of fieldwork, this article details the explanatory models relating to the chains of contamination and their hybridization between biomedical models and sorcery and/or political logic. By also addressing the impacts of discourse on the animal origin of the virus, this article contributes to an analysis of the gap between the different understandings and responses to the epidemic phenomenon and the scale of the response.


Cet article s'attache à décrire les différents modèles de causalité du malheur et leurs constructions sociales suite à l'émergence de la neuvième épidémie de la maladie à virus Ebola dans la province de l'Équateur, en République démocratique du Congo en mai 2018. Fondé sur un corpus de données qualitatives collecté lors de trois semaines de terrain, l'article détaille les modèles explicatifs ayant trait aux chaînes de contaminations et leur hybridation entre modèle biomédical et logique mystique et/ou politique. En traitant également de la réception du discours scientifique sur l'origine animale du virus, cet article contribue à une analyse du fossé existant entre les différentes compréhensions et réactions locales et biomédicales face au phénomène épidémique et à l'ampleur de la riposte.


Asunto(s)
Ebolavirus , Epidemias , Fiebre Hemorrágica Ebola , Antropología Cultural , República Democrática del Congo/epidemiología , Brotes de Enfermedades , Fiebre Hemorrágica Ebola/epidemiología , Humanos
3.
Science ; 258(5085): 1145-8, 1992 Nov 13.
Artículo en Inglés | MEDLINE | ID: mdl-1439823

RESUMEN

The common laboratory strain of bacteriophage lambda--lambda wild type or lambda PaPa--carries a frameshift mutation relative to Ur-lambda, the original isolate. The Ur-lambda virions have thin, jointed tail fibers that are absent from lambda wild type. Two novel proteins of Ur-lambda constitute the fibers: the product of stf, the gene that is disrupted in lambda wild type by the frameshift mutation, and the product of gene tfa, a protein that is implicated in facilitating tail fiber assembly. Relative to lambda wild type, Ur-lambda has expanded receptor specificity and adsorbs to Escherichia coli cells more rapidly.


Asunto(s)
Bacteriófago lambda/genética , Mutación del Sistema de Lectura , Proteínas de la Cola de los Virus/genética , Adsorción , Secuencia de Aminoácidos , Bacteriófago lambda/química , Bacteriófago lambda/fisiología , Mapeo Cromosómico , Escherichia coli/genética , Escherichia coli/fisiología , Escherichia coli/efectos de la radiación , Genes Virales , Microscopía Electrónica , Datos de Secuencia Molecular , Peso Molecular , Rayos Ultravioleta , Proteínas de la Cola de los Virus/química
4.
Science ; 220(4594): 261-8, 1983 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-6340198

RESUMEN

Artificial intelligence, long a topic of basic computer science research, is now being applied to problems of scientific, technical, and commercial interest. Some consultation programs, although limited in versatility, have achieved levels of performance rivaling those of human experts. A collateral benefit of this work is the systematization of previously unformalized knowledge in areas such as medical diagnosis and geology.


Asunto(s)
Computadores , Antibacterianos/uso terapéutico , Infecciones Bacterianas/tratamiento farmacológico , Diagnóstico por Computador , Humanos , Investigación , Análisis de Sistemas
5.
Science ; 217(4563): 927-9, 1982 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-17747953

RESUMEN

A computer program that uses artificial intelligence techniques has successfully identified the location of a porphyry molybdenum deposit. Given geological maps of readily available predrilling exploration data for Mount Tolman in Washington State and using rules obtained from a porphyry molybdenum exploration specialist, the program (called PROSPECTOR) identified the location of previously unknown ore-grade mineralization. This appears to be the first reported determination of the location of mineralization by such a computer-based approach.

6.
Science ; 289(5487): 2129-33, 2000 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-11000116

RESUMEN

The crystal structure of the double-stranded DNA bacteriophage HK97 mature empty capsid was determined at 3.6 angstrom resolution. The 660 angstrom diameter icosahedral particle contains 420 subunits with a new fold. The final capsid maturation step is an autocatalytic reaction that creates 420 isopeptide bonds between proteins. Each subunit is joined to two of its neighbors by ligation of the side-chain lysine 169 to asparagine 356. This generates 12 pentameric and 60 hexameric rings of covalently joined subunits that loop through each other, creating protein chainmail: topologically linked protein catenanes arranged with icosahedral symmetry. Catenanes have not been previously observed in proteins and provide a stabilization mechanism for the very thin HK97 capsid.


Asunto(s)
Cápside/química , Siphoviridae/química , Asparagina/química , Asparagina/metabolismo , Cápside/metabolismo , Fenómenos Químicos , Química Física , Cristalografía por Rayos X , Enlace de Hidrógeno , Lisina/química , Lisina/metabolismo , Modelos Moleculares , Conformación Proteica , Pliegue de Proteína , Estructura Cuaternaria de Proteína , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína , Siphoviridae/metabolismo
7.
Science ; 292(5517): 744-8, 2001 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-11326105

RESUMEN

Large-scale conformational changes transform viral precursors into infectious virions. The structure of bacteriophage HK97 capsid, Head-II, was recently solved by crystallography, revealing a catenated cross-linked topology. We have visualized its precursor, Prohead-II, by cryoelectron microscopy and modeled the conformational change by appropriately adapting Head-II. Rigid-body rotations ( approximately 40 degrees) cause switching to an entirely different set of interactions; in addition, two motifs undergo refolding. These changes stabilize the capsid by increasing the surface area buried at interfaces and bringing the cross-link-forming residues, initially approximately 40 angstroms apart, close together. The inner surface of Prohead-II is negatively charged, suggesting that the transition is triggered electrostatically by DNA packaging.


Asunto(s)
Cápside/química , Cápside/metabolismo , Precursores de Proteínas/química , Precursores de Proteínas/metabolismo , Siphoviridae/fisiología , Ensamble de Virus , Secuencias de Aminoácidos , Microscopía por Crioelectrón , Cristalografía por Rayos X , ADN Viral/metabolismo , Procesamiento de Imagen Asistido por Computador , Modelos Moleculares , Conformación Proteica , Pliegue de Proteína , Estructura Terciaria de Proteína , Subunidades de Proteína , Siphoviridae/química , Siphoviridae/ultraestructura , Propiedades de Superficie
8.
J Clin Invest ; 79(4): 1249-53, 1987 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-3494046

RESUMEN

The cause of bone loss in postmenopausal osteoporosis--decreased bone formation or increased bone resorption--is controversial. Synthesis of bone--Gla protein (BGP), a specific osteoblast product, is stimulated by 1,25-dihydroxyvitamin D3 [1,25(OH)2D] in vitro. Thus, increases in serum BGP levels during 1,25(OH)2D administration might provide a useful dynamic index of osteoblast function. We compared 14 postmenopausal osteoporotic women with 12 age-matched postmenopausal normal women before and during 6 d of 1,25(OH)2D administration (2.0 micrograms/d). Serum BGP levels were similar at baseline and increased during treatment in both groups (P less than 0.001). However, trend analysis showed a greater (P less than 0.01) increase in the osteoporotic women. These data do not support the hypothesis that defective osteoblast function is the major cause of bone loss in postmenopausal osteoporosis.


Asunto(s)
Calcitriol , Menopausia , Osteoblastos/fisiología , Osteoporosis/fisiopatología , Fosfatasa Alcalina/sangre , Calcifediol/sangre , Calcio/orina , Proteínas de Unión al Calcio/sangre , Creatinina/orina , Femenino , Humanos , Hidroxiprolina/orina , Persona de Mediana Edad , Osteocalcina
9.
Int J Gynaecol Obstet ; 99(2): 150-6, 2007 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-17628563

RESUMEN

OBJECTIVE: The purpose of the Women's Health Study of Accra was to provide an assessment of the prevalence of communicable and non-communicable illnesses. METHOD: This was a prospective, community-based study that included an interview for medical illnesses, a comprehensive physical examination, and laboratory testing. A total of 1328 women were examined at Korle Bu Teaching Hospital, University of Ghana. RESULTS: Prevalent conditions included poor vision (66.8%), malaria (48.7%), pain (42.8%), poor dentition (41.6%), hypertension (40.2%), obesity (34.7%), arthritis (27.1%), chronic back pain (19.4%), abnormal rectal (16.0%) and pelvic examinations (12.7%), HIV in women age 24-29 (8.3%), and hypercholesterolemia (22.7%). Increasing age, lack of formal education, and low-income adversely affected health conditions. CONCLUSION: The high prevalence of preventable illnesses in this expanding urban population indicates that the health care services are obligated to develop and provide screening, preventive strategies and treatment for both general health and gynecologic health conditions.


Asunto(s)
Estado de Salud , Población Urbana/estadística & datos numéricos , Adolescente , Adulto , Índice de Masa Corporal , Escolaridad , Femenino , Ghana , Humanos , Persona de Mediana Edad , Prevención Primaria , Estudios Prospectivos , Medicina Reproductiva , Clase Social , Salud de la Mujer
10.
Cancer Res ; 46(12 Pt 1): 6503-8, 1986 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-3779658

RESUMEN

A monoclonal antibody to carcinoembryonic antigen (CEA) labeled with 111In (Indacea) was used to image tumors in patients with colorectal cancer. The anti-CEA antibody has a high affinity (2.6 X 10(10) M-1) for CEA and does not cross-react with normal cross-reacting antigen, biliary glycoprotein-1, or tumor-extracted, CEA-related antigen. During the course of these studies, it was noted that a significant number of male patients (20 of 27, 74%) showed uptake of Indacea in the testes. In order to determine if the Indacea uptake was specific, 20 testicular specimens were analyzed by immunohistological methods using five different anti-CEA CEA monoclonal antibodies recognizing five different epitopes on CEA. In 18 cases (90%) germ cells were uniformly stained by all five antibodies. Fresh frozen testis tissue was homogenized in water and precipitated with 1.0 M perchloric acid. The supernatant contained a CEA-like material as measured by an enzyme immunoassay specific for CEA. The same supernatant was radiolabeled with 125I and immunoprecipitated with anti-CEA monoclonal antibodies. Sodium dodecyl sulfate:polyacrylamide gel electrophoresis of the immunoprecipitates revealed a single species (Mr 180,000) which was indistinguishable from CEA. This study documents the first description of CEA in the germ cells of normal testis. The CEA in the testis was accessible to circulating monoclonal antibodies in the majority of male patients tested.


Asunto(s)
Anticuerpos Monoclonales , Antígeno Carcinoembrionario/análisis , Indio , Radioisótopos , Espermatozoides/inmunología , Testículo/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Antígeno Carcinoembrionario/inmunología , Neoplasias del Colon/diagnóstico por imagen , Electroforesis en Gel de Poliacrilamida , Humanos , Masculino , Persona de Mediana Edad , Cintigrafía , Neoplasias del Recto/diagnóstico por imagen , Testículo/inmunología , Testículo/patología
11.
Cancer Res ; 46(12 Pt 1): 6494-502, 1986 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-3779657

RESUMEN

Patients with primary, recurrent, or metastatic colorectal adenocarcinoma were given injections of 200 micrograms of anticarcinoembryonic antigen (CEA) monoclonal antibody labeled with 2 mCi of 111In (Indacea). Patients were imaged at 24 and 48 h. Celiotomy was performed on 40 patients between 3 and 17 days post-Indacea injection. Of 16 primary tumors, 11 (69%) were imaged. Of six extrahepatic recurrences, none was imaged. Intrahepatic metastases were visualized as negative images in 10 of 24 (42%) patients. On the basis of the activity in tissue expressed as a percentage of the total radioactive dose per kg injected into the patient (% ID/kg), extrahepatic tumors that were imaged using Indacea had a significant uptake of radiolabel in the tumor [5.99 +/- 0.91% ID/kg (SE)] and in the associated normal mesenteric lymph nodes (12.0 +/- 2.4% ID/kg). The CEA content of these tumors was high (13.3 +/- 4.7 micrograms/g), and, histologically, the CEA was located primarily apically or intraluminally. Intrahepatic tumor imaging correlated only with tumor size. The greatest Indacea uptake was seen in normal liver (22.1 +/- 3.2% ID/kg). Low Indacea uptake was seen in fat (0.21 +/- 0.05% ID/kg) and bowel wall (1.11 +/- 0.17% ID/kg). In conclusion, Indacea imaging of colorectal carcinoma is specific for high concentrations of accessible CEA in CEA-bearing tumors or in lymph nodes draining these tumors. The successful clinical use of monoclonal antibodies for tumor imaging and therapy will require careful selection of patients for a number of antigen-related parameters including antigen content and distribution in tumors. This information will only come from careful correlation between image results and tissue analysis. High uptake by normal liver tissue is the major unresolved problem with labeled antibody imaging.


Asunto(s)
Anticuerpos Monoclonales , Antígeno Carcinoembrionario/análisis , Neoplasias del Colon/diagnóstico por imagen , Indio , Radioisótopos , Neoplasias del Recto/diagnóstico por imagen , Antígeno Carcinoembrionario/inmunología , Neoplasias del Colon/inmunología , Humanos , Hígado/diagnóstico por imagen , Neoplasias Hepáticas/secundario , Ganglios Linfáticos/diagnóstico por imagen , Cuidados Preoperatorios , Cintigrafía , Neoplasias del Recto/inmunología
12.
FEMS Microbiol Rev ; 17(1-2): 41-6, 1995 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-7669350

RESUMEN

The head assembly pathway of bacteriophage HK97 shares many features with head assembly pathways determined for other dsDNA phages, and it also provides examples of novel variations on the basic theme. We describe aspects of two specific steps in the assembly pathway, the covalent cross-linking among the assembled head protein subunits and the cleavage of those subunits that takes place earlier in the pathway. Comparisons of head assembly pathways among different phages, as well as comparisons of the organization of the genes that specify those pathways, suggest the range of different solutions phages have found to common assembly problems and give insight into the evolutionary histories of these assembly processes.


Asunto(s)
Bacteriófagos/química , Cápside/química , Evolución Biológica , Genes Virales , Conformación Proteica
13.
J Mol Biol ; 247(4): 636-47, 1995 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-7723020

RESUMEN

We report studies to determine which bacteriophage genes are required for assembly of phage HK97 proheads and what roles they play. We identify the gene encoding the major capsid protein of phage HK97 and report its DNA sequence, together with the DNA sequences of the two genes immediately upstream from it. When the capsid protein is expressed from a plasmid in the absence of other phage-encoded proteins, it assembles, with good efficiency and accuracy into prohead-like structures composed of the unprocessed 42 kDa capsid protein. No separately encoded scaffolding protein is required for this assembly. If the 25 kDa product of the next gene upstream is co-expressed with the capsid protein, the prohead structures that are produced undergo the normal morphogenetic cleavage, which removes 102 amino acids from the N terminus of each subunit, leaving 31 kDa subunits. The 25 kDa protein is therefore probably a phage-encoded protease. The third gene, upstream from the protease gene, encodes the portal protein. Presence of the portal protein is not required for assembly of the capsid protein. Analysis of the phenotypes of four single amino acid-substitution mutants in the capsid-protein gene leads to several insights into the functions of the capsid protein and its interactions with the putative protease.


Asunto(s)
Bacteriófagos/genética , Cápside/genética , Secuencia de Aminoácidos , Bacteriófagos/química , Secuencia de Bases , Cápside/química , ADN Viral/genética , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida
14.
J Mol Biol ; 247(4): 618-35, 1995 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-7723019

RESUMEN

Bacteriophage HK97 builds its head shell from a 42 kDa major head protein, but neither this 42 kDa protein nor its processed, 31 kDa form is found in the mature head. Instead, each of the major head-protein subunits is covalently cross-linked into oligomers of five, six or more by a protein cross-linking reaction that occurs both in vivo and in vitro. Mutants that block prohead maturation lead to the accumulation of one of two types of proheads, termed Prohead I and Prohead II. Prohead I is assembled from about 415 copies of the 42 kDa (384 amino acids) protein subunit and accumulates in infections by mutant amU4. Following assembly, the N-terminal 102 amino acids of each subunit are removed, leaving a prohead shell constructed of 31 kDa subunits, called Prohead II, which accumulates in infections by mutant amC2. During DNA packaging, when the prohead shell expands, all of the head protein subunits become covalently cross-linked to other subunits. Purified Prohead II (or, less completely, Prohead I) becomes cross-linked in vitro in response to any of a number of conditions that induce shell expansion, including conditions commonly used for protein analysis. In vitro cross-linking occurs efficiently in the absence of added cofactors of enzymes, and we propose that cross-linking is catalyzed by shell subunits themselves. Shell expansion is easily monitored by observing a decrease in electrophoretic mobility of Prohead II in agarose gels. Using the mobility shift in agarose gel to monitor expansion and SDS/gel electrophoresis to monitor cross-linking in vitro, we find that expansion precedes and is required for cross-linking, and we propose that expansion triggers the cross-linking reaction. Comparison of peptides isolated from Prohead II and in vitro cross-linked Prohead II shows a single altered major cross-link peptide in which a lysine, originating from lysine169 of the protein sequence, is linked to asparagine356, presumably derived from the neighboring subunit. Examination of the cross-link-containing peptide by mass spectrometry shows that the cross-link bond is an amide between the side-chains of the lysine and the asparagine residues.


Asunto(s)
Bacteriófagos/química , Cápside/química , Secuencia de Aminoácidos , Reactivos de Enlaces Cruzados , Datos de Secuencia Molecular , Conformación Proteica , Estructura Secundaria de Proteína
15.
J Mol Biol ; 299(1): 27-51, 2000 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-10860721

RESUMEN

We report the complete genome DNA sequences of HK97 (39,732 bp) and HK022 (40,751 bp), double-stranded DNA bacteriophages of Escherichia coli and members of the lambdoid or lambda-like group of phages. We provide a comparative analysis of these sequences with each other and with two previously determined lambdoid family genome sequences, those of E. coli phage lambda and Salmonella typhimurium phage P22. The comparisons confirm that these phages are genetic mosaics, with mosaic segments separated by sharp transitions in the sequence. The mosaicism provides clear evidence that horizontal exchange of genetic material is a major component of evolution for these viruses. The data suggest a model for evolution in which diversity is generated by a combination of illegitimate and homologous recombination and mutational drift, and selection for function produces a population in which most of the surviving mosaic boundaries are located at gene boundaries or, in some cases, at protein domain boundaries within genes. Comparisons of these genomes highlight a number of differences that allow plausible inferences of specific evolutionary scenarios for some parts of the genome. The comparative analysis also allows some inferences about function of genes or other genetic elements. We give examples for the generalized recombination genes of HK97, HK022 and P22, and for a putative headtail adaptor protein of HK97 and HK022. We also use the comparative approach to identify a new class of genetic elements, the morons, which consist of a protein-coding region flanked by a putative delta 70 promoter and a putative factor-independent transcription terminator, all located between two genes that may be adjacent in a different phage. We argue that morons are autonomous genetic modules that are expressed from the repressed prophage. Sequence composition of the morons implies that they have entered the phages' genomes by horizontal transfer in relatively recent evolutionary time.


Asunto(s)
Bacteriófago lambda/genética , Evolución Molecular , Genoma Viral , Recombinación Genética/genética , Secuencia de Aminoácidos , Bacteriófago P22/genética , Bacteriófago lambda/química , Composición de Base , Secuencia de Bases , Secuencia Conservada/genética , ARN Polimerasas Dirigidas por ADN/fisiología , Sistema de Lectura Ribosómico/genética , Genes Virales/genética , Variación Genética/genética , Modelos Genéticos , Datos de Secuencia Molecular , Mutación/genética , Conformación de Ácido Nucleico , Sistemas de Lectura Abierta/genética , Operón/genética , Filogenia , Regiones Promotoras Genéticas/genética , Factor sigma/fisiología , Regiones Terminadoras Genéticas/genética , Proteínas de la Cola de los Virus/química , Proteínas de la Cola de los Virus/genética
16.
J Mol Biol ; 253(1): 86-99, 1995 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-7473720

RESUMEN

Bacteriophage capsid assembly pathways provide excellent model systems to study large-scale conformational changes and other mechanisms that regulate the formation of macromolecular complexes. These capsids are formed from proheads: relatively fragile precursor particles which mature by undergoing extensive remodeling. Phage HK97 employs novel features in its strategy for building capsids, including assembly without a scaffolding protein, and the formation of a network of covalent cross-links between neighboring subunits in the mature virion. In addition, proteolytic cleavage of the capsid protein from 42 kDa to 31 kDa is essential for maturation. To investigate the structural bases for proteolysis and cross-linking, we have used cryo-electron micrographs to reconstruct the three-dimensional structures of purified particles from four discrete stages in the assembly pathway: Prohead I, Prohead II, Head I and Head II. Prohead I has icosahedral T = 7 packing of blister-shaped pentamers and hexamers. The pentamers are 5-fold symmetric, but the hexamers exhibit an unusual departure from 6-fold symmetry, as if two trimers had undergone a shear dislocation of about 25 A. Proteolytic conversion to Prohead II leaves the outer surface largely unchanged, but a major loss of density from the inner surface is observed, which we infer to represent the excision of the amino-terminal domains of the capsid protein. Upon expansion to the Head I state, the capsid becomes markedly larger, thinner walled, and more polyhedral: moreover, the capsomer shapes change radically; especially notable is the disappearance of the large hexon dislocation. No differences between Head I and the covalently cross-linked Head II could be observed at the current resolution of about 25 A, from which we infer that it is the conformational rearrangements effected by expansion that create the micro-environments needed for the autocatalytic formation of the isodipeptide bonds found in the mature virions ("pseudo-active sites").


Asunto(s)
Cápside/ultraestructura , Colifagos/fisiología , Ensamble de Virus/fisiología , Secuencia de Aminoácidos , Cápside/biosíntesis , Cápside/química , Cápside/metabolismo , Procesamiento de Imagen Asistido por Computador , Microscopía Electrónica/métodos , Microscopía Electrónica de Transmisión de Rastreo , Conformación Proteica , Análisis de Secuencia
17.
Arch Intern Med ; 149(11): 2597-600, 1989 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-2818118

RESUMEN

We reviewed the clinical characteristics of 10 patients with thyrotoxic periodic paralysis. In these patients, a relatively uniform group of young men, the periodic paralysis developed nearly concurrently with the onset of hyperthyroidism. The attacks were precipitated most frequently by rest and by exercise and, occasionally, by ingestion of a large carbohydrate load. In each patient, the paralysis resolved on return of euthyroidism. The approximate incidence rate for thyrotoxic periodic paralysis in our largely white North American patient population (all hyperthyroidism cases) ranged from 0.1% to 0.2%, which is one tenth the rate reported for Oriental populations. In 7 patients, electrodiagnostic testing revealed characteristic changes in compound muscle action potential amplitude in response to exercise of the muscle being tested.


Asunto(s)
Parálisis Periódicas Familiares/fisiopatología , Tirotoxicosis/complicaciones , Adulto , Electromiografía , Humanos , Masculino , Conducción Nerviosa , Parálisis Periódicas Familiares/etiología , Esfuerzo Físico , Pruebas de Función de la Tiroides , Tirotoxicosis/fisiopatología , Tirotoxicosis/terapia
18.
J Clin Endocrinol Metab ; 66(5): 951-7, 1988 May.
Artículo en Inglés | MEDLINE | ID: mdl-3258870

RESUMEN

We measured the serum concentrations of 2 biochemical markers of bone formation, bone Gla-protein (BGP) and bone alkaline phosphatase (BAP), in 164 normal subjects and 164 patients with metabolic bone disorders. The data were reported as Z scores (deviation in SDs from the sex-specific age regression in normal subjects). Both serum BGP and BAP distinguished abnormalities well (mean Z scores for BGP and BAP, respectively) and gave concordant results in patients with hypoparathyroidism (-1.7, -1.4), hyperthyroidism (+1.1, +1.8), primary hyperparathyroidism (+3.6, +2.5), acromegaly (+1.2, +2.8), and postmenopausal osteoporosis (+0.4, +1.9). The 2 markers gave discordant results, however, in patients with glucocorticoid excess (-2.4, +0.9), Paget's disease (+1.8, +41.8), chronic renal failure (+16.3, +0.4), and osteolytic metastases (-1.4, +5.9). These discrepancies may have occurred because serum BGP and BAP concentrations reflect different aspects of osteoblast function or because there are differences in their clearance from the circulation. Consequently, more information is derived about the level of bone formation across the wide range of metabolic bone disorders when both biochemical markers are assayed.


Asunto(s)
Fosfatasa Alcalina/sangre , Enfermedades Óseas Metabólicas/sangre , Proteínas de Unión al Calcio/sangre , Adulto , Factores de Edad , Enfermedades Óseas Metabólicas/enzimología , Huesos/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Osteocalcina , Factores Sexuales
19.
J Nucl Med ; 29(1): 103-9, 1988 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-3335916

RESUMEN

Inverse correlations of tumor uptake (u), measured in percent injected dose per gram, with tumor mass (m) are demonstrated for phospholipid vesicle, nonspecific and specific monoclonal antibody tracers. Correlation coefficients implied u = B mA in 11 different animal experiments. Experimental exponent (A) values lay in the range -0.28-0.64 with a mean of -0.43 while intercept (B) values varied from 3 to 18. Spherical and cylindrical tumor models implied exponents of -0.33 and -0.5, respectively. Comparison of three implantation sites of the human LS174T xenograft revealed a narrow range of exponents (-0.38- -0.46) indicating a consistent geometry for this tumor. Blood flow to the lesion site and inside its volume (as dictated by tumor size) are factors in tumor uptake. Our results indicate that biodistribution data should include the variation of tumor uptake with mass. For less than 10 g lesions, we predict that radiation absorbed dose will be highly dependent upon tumor size.


Asunto(s)
Anticuerpos Monoclonales , Radioisótopos de Indio , Neoplasias Experimentales/diagnóstico por imagen , Animales , Modelos Teóricos , Fosfolípidos , Cintigrafía , Análisis de Regresión , Distribución Tisular
20.
Surgery ; 110(3): 552-6, 1991 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-1887382

RESUMEN

Breast cancer is a common primary malignancy in women. On rare occasion the breast is also the site of metastatic disease. This report describes the evaluation of breast and axillary masses in a patient with known ovarian cancer, including the radiographic evaluation and special immunohistochemical stains with CA-125. Flow cytometric determinations and hormonal receptor analysis on both the primary and metastatic tumors demonstrate similar biologic characteristics. Both tumor sites demonstrated positive CA-125 staining, aneuploid DNA populations, moderately positive estrogen receptor content, and negative progesterone receptors. The mammogram demonstrated a well-circumscribed lesion with several areas of microcalcifications. Blood-borne metastasis from the ovary to the breast can show a varied clinical picture that can be differentiated from that of a primary breast carcinoma.


Asunto(s)
Neoplasias de la Mama/secundario , Cistadenocarcinoma/patología , Neoplasias Ováricas/patología , Antígenos de Carbohidratos Asociados a Tumores/análisis , Axila , Cistadenocarcinoma/secundario , ADN de Neoplasias/análisis , Femenino , Humanos , Metástasis Linfática , Persona de Mediana Edad
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