RESUMEN

Physical activities are associated with the health of transition dairy cows and pregnancy outcomes are positively related to early resumption of postpartum estrous cycles. The objective was to assess key metabolites and patterns of prepartum and postpartum physical activity as they relate to the onset of first postpartum ovulation in lactating dairy cows. Close-up dry Holstein cows (n = 82) and late gestation heifers (n = 78) were enrolled beginning 3 wk before expected calving date (Day 0). Cows were fit with Cow SensOor ear tags to assess transitional changes in eating, resting, rumination, high activity, and ear-surface temperatures. Rectal temperatures were assessed and blood samples were collected on Days 0, 3, 7, and 14 to measure concentrations of glucose, free fatty acids (FFA), ß-hydroxybutyrate (BHB), calcium, and haptoglobin. Body condition scores (BCS) and body weights (BW) were measured weekly, and blood samples were collected weekly from Day 21 ± 3 through 70 ± 3 to quantify changes in progesterone to detect luteal function after ovulation. Cows first ovulating before median Day 33 were classified as early (n = 76), whereas those first ovulating after Day 33 were classified as late (n = 84). Early ovulating cows first ovulated earlier (P < 0.001) than the late ovulation cows (24.3 ± 1.2 d [range: 16-32 d] vs. 48.8 ± 1.2 d [range: 33-74 d]), respectively. Mean days to first ovulation excluded seven cows that failed to ovulate before insemination. Compared with late ovulating cows, early ovulating cows had lesser (P < 0.05) concentrations of FFA, BHB, and haptoglobin on Days 0, 3, 7, and 14 in addition to having lesser (P < 0.05) rectal temperatures and ear-surface temperatures. Ear-surface temperatures began to decrease 4 d before parturition and remained less (P < 0.05) after calving than cows that subsequently ovulated late. Early ovulating cows tended (P = 0.07) to spend more time eating, and less (P = 0.02) time resting and being active during the first 3 wk after calving, and lost less (P = 0.03) BW and BCS during the first 9 wk compared with late ovulating cows. Although no differences were detected in yields of milk or energy-corrected milk during the first 9 wk after calving, early compared with late ovulating cows produced more (P < 0.01) milk protein. We concluded that metabolic measures during the first 2 wk after calving, and physical and behavioral traits are associated with the onset of postpartum ovarian activity.

Asunto(s)

Lactancia , Periodo Posparto , Ácido 3-Hidroxibutírico , Animales , Bovinos , Ácidos Grasos no Esterificados , Femenino , Leche , Ovulación , Embarazo

RESUMEN

It was hypothesized that rumen-protected glucose (RPG) in diets of dairy cows increases concentrations of insulin resulting in greater blood progesterone concentrations because elevated insulin decreases activity of liver enzymes inactivating steroid hormones. Timing of ovulation was synchronized among 64 postpartum Holstein cows using GnRH and PGF2α (Day 0 = ovulation). Cows were milked thrice daily and assigned randomly a basal diet supplemented with 0, 1, 2, or 4 kg of an RPG product in place of corn grain, top-dressed in the diet beginning on Day -3. Blood was collected pre- and post-prandial on Days 0, 2, and 4 to determine plasma glucose and insulin concentrations and daily from Days 2 through 12. Intake of crude protein and energy-soluble carbohydrates increased linearly with dose, whereas starch intake decreased linearly with dose. Neither daily milk yield nor dry matter intake (DMI), energy-corrected milk (ECM), somatic cell count, or percentages of milk fat, protein and lactose on Day 8 differed among dietary treatments. Neither pre- nor post-prandial changes in plasma glucose differed among treatments. In contrast, post-prandial glucose decreased from Days 0 through 4. A change in plasma insulin (post-prandial minus pre-prandial) was detected. Milk urea nitrogen increased linearly with RPG dose. Concentrations of progesterone were unaffected by RPG dose. It is concluded that insulin response to RPG was decreased relative to the control and RPG supplementation linearly increased crude protein intake and milk urea nitrogen with increasing dose, but did not affect concentrations of progesterone, milk yield, or dry matter intake.

Asunto(s)

Bovinos/sangre , Conducta Alimentaria/efectos de los fármacos , Glucosa/administración & dosificación , Glucosa/farmacología , Lactancia/fisiología , Rumen/fisiología , Animales , Bovinos/metabolismo , Femenino , Glucosa/metabolismo , Leche/química , Progesterona/sangre , Progesterona/metabolismo , Urea/química , Urea/metabolismo

RESUMEN

We report 11 patients with laryngeal tuberculosis seen in our hospital, January 1990 to July 2000. Eight were men and all cases presented with dysphonia and/or disphagia. In 8 pulmonary tuberculosis was associated. Mycobacterium tuberculosis was isolated from the sputum in 7 patients. Granulomatous laryngitis was demonstrated in the eight patients with laryngeal biopsy. The evolution with medical treatment was favourable in all patients.

Asunto(s)

Tuberculosis Laríngea , Adulto , Femenino , Humanos , Masculino , Estudios Retrospectivos , Tuberculosis Laríngea/diagnóstico , Tuberculosis Laríngea/tratamiento farmacológico

RESUMEN

Describimos 11 enfermos con tuberculosis laríngea observados en nuestro hospital desde enero de 1990 a julio de 2000. Ocho eran varones de edad superior a los 30 años y diez fumadores importantes. El diagnóstico se realizó en una media de 43 días desde que comenzaron con las manifestaciones clínicas. Todos referían disfonía y/o disfagia y en 8 se diagnosticó tuberculosis pulmonar asociada. En 7enfermos se aisló Mycobacterium tuberculosis en esputo. En los 8 casos que se realizó biopsia laríngea, se demostró la presencia de granulomas. Con tratamiento médico antituberculoso, la evolución fue satisfactoria en todos los casos, no habiéndose observado en ninguno clínica residual (AU)

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We report 11 patients with laryngeal tuberculosis seen in our hospital, January 1990 to July 2000. Eight were men and all cases presented with dysphonia and/or disphagia. In 8 pulmonary tuberculosis was associated. Mycobacterium tuberculosis was isolated from the sputum in 7 patients. Granulomatous laryngitis was demonstrated in the eight patients with laryngeal biopsy. The evolution with medical treatment was favourable in all patients (AU)

Asunto(s)

Adulto , Masculino , Femenino , Humanos , Tuberculosis Laríngea/diagnóstico , Tuberculosis Laríngea/tratamiento farmacológico , Estudios Retrospectivos

RESUMEN

The conformational properties of the molecular chaperone GroEL in the presence of ATP, its non-hydrolyzable analog 5'-adenylimidodiphosphate (AMP-PNP), and ADP have been analyzed by differential scanning calorimetry (DSC), Fourier-transform infra-red (FT-IR) and fluorescence spectroscopy. Nucleotide binding to one ring promotes a decrease in the Tm value of the GroEL thermal transition that is reversed when both rings are filled with nucleotide, indicating that the sequential occupation of the two protein rings by these nucleotides has different effects on the GroEL thermal denaturation process. In addition, ATP induces a conformational change in GroEL characterized by (a) the appearance of a reversible low temperature endotherm in the DSC profiles of the protein, and (b) an enhanced binding of the hydrophobic probe 8-anilino-naphthalene-1-sulfonate (ANS), which strictly depends on ATP hydrolysis. The similar sensitivity to K+ of the temperature range where activation of the GroEL ATPase activity, the low temperature endotherm, and the increase of the ANS fluorescence are abserved strongly indicates the existence of a conformational state of GroEL during ATP hydrolysis, different from that generated on ADP or AMP-PNP binding. To achieve this intermediate conformation, GroEL mainly modifies its tertiary and quaternary structures, leading to an increased exposure of hydrophobic surfaces, with minor rearrangements of its secondary structure.

Asunto(s)

Adenosina Trifosfato/metabolismo , Chaperonina 60/química , Chaperonina 60/metabolismo , Adenosina Difosfato/metabolismo , Adenilil Imidodifosfato/metabolismo , Rastreo Diferencial de Calorimetría , Calor , Hidrólisis , Conformación Proteica , Desnaturalización Proteica , Espectrometría de Fluorescencia , Espectroscopía Infrarroja por Transformada de Fourier

RESUMEN

BACKGROUND: The actin-binding site of several cytoskeletal proteins is comprised of two calponin homology (CH) domains in a tandem arrangement. As a single copy, the CH domain is also found in regulatory proteins in muscle and in signal-transduction proteins. The three-dimensional structures of three CH domains are known, but they have not yet clarified the molecular details of the interaction between actin filaments and proteins harbouring CH domains. RESULTS: We have compared the crystal structure of a CH domain from beta-spectrin, which has been refined to 1.1 A resolution, with the two CH domains that constitute the actin-binding region of fimbrin. This analysis has allowed the construction of a structure-based sequence alignment of CH domains that can be used in further comparisons of members of the CH domain family. The study has also improved our understanding of the factors that determine domain architecture, and has led to discussion on the functional differences that seem to exist between subfamilies of CH domains, as regards binding to F-actin. CONCLUSIONS: Our analysis supports biochemical data that implicate a surface centered at the last helix of the N-terminal CH domain as the most probable actin-binding site in cytoskeletal proteins. It is not clear whether the C-terminal domains of the tandem arrangement or the single CH domains have this function alone. This may imply that although the CH domains are homologous and have a conserved structure, they may have evolved to perform different functions.

Asunto(s)

Actinas/metabolismo , Proteínas de Unión al Calcio/química , Secuencia de Aminoácidos , Animales , Sitios de Unión , Proteínas de Unión al Calcio/metabolismo , Cristalografía por Rayos X , Humanos , Proteínas de Microfilamentos , Modelos Moleculares , Datos de Secuencia Molecular , Unión Proteica , Conformación Proteica , Homología de Secuencia de Aminoácido , Calponinas

RESUMEN

The sarcomeric Z-disk, the anchoring plane of thin (actin) filaments, links titin (also called connectin) and actin filaments from opposing sarcomere halves in a lattice connected by alpha-actinin. We demonstrate by protein interaction analysis that two types of titin interactions are involved in the assembly of alpha-actinin into the Z-disk. Titin interacts via a single binding site with the two central spectrin-like repeats of the outermost pair of alpha-actinin molecules. In the central Z-disk, titin can interact with multiple alpha-actinin molecules via their C-terminal domains. These interactions allow the assembly of a ternary complex of titin, actin and alpha-actinin in vitro, and are expected to constrain the path of titin in the Z-disk. In thick skeletal muscle Z-disks, titin filaments cross over the Z-disk centre by approximately 30 nm, suggesting that their alpha-actinin-binding sites overlap in an antiparallel fashion. The combination of our biochemical and ultrastructural data now allows a molecular model of the sarcomeric Z-disk, where overlapping titin filaments and their interactions with the alpha-actinin rod and C-terminal domain can account for the essential ultrastructural features.

Asunto(s)

Actinina/metabolismo , Proteínas Musculares/metabolismo , Proteínas Quinasas/metabolismo , Sarcómeros/química , Citoesqueleto de Actina/metabolismo , Actinina/química , Actinas/análisis , Secuencia de Aminoácidos , Animales , Pollos , Conectina , Humanos , Ligandos , Datos de Secuencia Molecular , Proteínas Musculares/análisis , Proteínas Musculares/química , Músculo Esquelético/química , Proteínas Quinasas/química , Conejos , Sarcómeros/metabolismo , Espectrina

RESUMEN

Replication-defective, highly purified retroviral vectors (Retrovector), at titers of 10(8) colony forming units/mL, were prepared that conferred either beta-galactosidase or herpes simplex thymidine kinase (HSV-TK) activity. 9L gliosarcoma cells, transduced efficiently in vitro, were highly sensitive to ganciclovir (GCV). The mean frequency of in situ transduction, measured by flow cytometry of single-cell tumor suspensions isolated from rat brains, was 3.2 +/- 0.6%; similar assessments were made by staining of beta-galactosidase or by immunohistochemistry with anti-HSV-TK. In vitro HSV-TK-transduced and G418-selected 9L-TK gliosarcoma tumors treated with GCV were eradicated in approximately 53% of the animals (10/19) at day 26, however, 89% (17/19) histologically showed < 1% tumor volume. Histologic evaluation at day 26 of animals with established 9L tumors treated with intralesional injection of HSV-TK vector followed by GCV treatment showed that 29% (4/14) had no tumor; 50% (7/14) had < 1% tumor volume. Regression of tumors proceeded over the time since the complete rate was increased at day 60. Neither HSV-TK vector particles nor GCV alone altered the histological profile of 9L tumors, but substantial numbers of CD4+ and CD8+ lymphocytes infiltrated the tumors of animals treated with both. In cured animals, the former tumor bed contained cell debris, immune cells, and fibroblasts and was without damage to adjacent brain. The efficacy of suicide gene therapy for rat gliosarcoma using highly purified virion vectors approaches that of packaging cell lines.

Asunto(s)

Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/patología , Vectores Genéticos/farmacología , Retroviridae/genética , Timidina Quinasa/genética , Animales , Antimetabolitos/farmacología , Neoplasias Encefálicas/genética , Linfocitos T CD4-Positivos , Linfocitos T CD8-positivos , División Celular/genética , Ganciclovir/farmacología , Terapia Genética/métodos , Vectores Genéticos/química , Vectores Genéticos/genética , Gentamicinas/farmacología , Bromuro de Hexadimetrina/química , Bromuro de Hexadimetrina/farmacología , Inmunohistoquímica , Masculino , Neoplasias Experimentales/tratamiento farmacológico , Neoplasias Experimentales/genética , Neoplasias Experimentales/patología , Ratas , Ratas Endogámicas , Simplexvirus/enzimología , Timidina Quinasa/efectos de los fármacos , Timidina Quinasa/metabolismo , Transducción Genética , beta-Galactosidasa/genética , beta-Galactosidasa/metabolismo

RESUMEN

The three-dimensional structure of the calponin homology domain present in many actin binding cytoskeletal and signal-transducing proteins has been determined at 2.0 A resolution.

Asunto(s)

Proteínas de Unión al Calcio/química , Proteínas del Citoesqueleto/química , Proteínas de Microfilamentos/química , Conformación Proteica , Actinina/química , Actinas/metabolismo , Secuencia de Aminoácidos , Animales , Sitios de Unión , Proteínas de Unión al Calcio/metabolismo , Cristalografía por Rayos X , Humanos , Modelos Moleculares , Datos de Secuencia Molecular , Estructura Secundaria de Proteína , Homología de Secuencia de Aminoácido , Transducción de Señal , Espectrina/química , Calponinas

RESUMEN

alpha-Lactalbumin (alphaLA) can adopt two different membrane-bound states depending on the physical properties of the lipid bilayer, namely adsorbed and inserted. The latter, but not the adsorbed state, is able to disrupt the permeability barrier of the bilayer. The structure of both states is strongly affected by the conformational properties of the alphaLA conformer considered: as protein flexibility increases the helical content of the membrane-bound conformation decreases, especially in the adsorbed form. Moreover, the adsorbed and the inserted states of those conformers containing 3 or 4 disulfides can interconvert in response to changes in the physical properties of the host membrane.

Asunto(s)

Lactalbúmina/química , Lactalbúmina/metabolismo , Membrana Dobles de Lípidos , Membrana Celular/metabolismo , Permeabilidad de la Membrana Celular , Liposomas/química , Liposomas/metabolismo , Modelos Biológicos , Conformación Proteica , Pliegue de Proteína , Espectrometría de Fluorescencia/métodos , Temperatura

RESUMEN

The effect of the structure and stability of several conformers of alpha-lactalbumin in aqueous solution on their association to negatively charged large unilamellar vesicles has been studied by circular dichroism, infrared spectroscopy, differential scanning calorimetry, and by content leakage experiments. Our results indicate that the affinity of alphaLA for negatively charged vesicles strongly depends on its conformational properties in solution. Analysis of the pH dependence of the interaction for the different conformers reveals that native-like, calcium-bound, ordered conformations become bilayer-associated through electrostatic forces. However, partially folded conformers are able to interact with negatively charged membranes at pHs higher than the protein isoelectric point, suggesting that hydrophobic interactions brought about by the exposure of hydorphobic residues at the protein surface are able to overcome the unfavorable electrostatic repulsion. Calorimetric and spectroscopic data in solution also indicate that substantial protein destabilization facilitates its subsequent membrane binding, and that the association process is favored for a set of conformers having significant secondary structure, but lacking native-like, stable tertiary structure. Aggregation of the unfolded alpha-lactalbumin molecules and burial of hydrophobic surfaces upon formation of ordered tertiary structure significantly reduce their membrane perturbing activity. These observations suggest that formation of a flexible strucutral intermediate of alpha-lactalbumin in solution is a prerequisite for its association with membranes.

Asunto(s)

Lactalbúmina/química , Liposomas , Fosfatidilcolinas , Fosfatidilgliceroles , Conformación Proteica , Pliegue de Proteína , Disulfuros , Estabilidad de Medicamentos , Concentración de Iones de Hidrógeno , Cinética , Lactalbúmina/metabolismo , Modelos Biológicos , Permeabilidad , Espectrofotometría Infrarroja

RESUMEN

The effect of membrane binding on the structure and stability of several conformers of alpha-lactalbumin was studied by infrared spectroscopy, circular dichroism, and fluorescence spectroscopy. In solution, under experimental conditions where all conformers interact with negatively charged membranes, they show significant conformational differences. However, binding to negatively charged membranes, which causes considerable changes in the structure of these conformers, leads to a remarkably similar protein conformation. The membrane-associated conformations are characterized by 1) a high helical content, greater than any of those found in solution, 2) a lack of stable tertiary structure, and 3) the disappearance of their thermotropic transition. These observations indicate that association with negatively charged membranes induces a conformational change within alpha-lactalbumin to a flexible, molten globule-like state.

Asunto(s)

Lactalbúmina/química , Membrana Dobles de Lípidos , Conformación Proteica , Apoproteínas/química , Dicroismo Circular , Ácido Edético , Lactalbúmina/metabolismo , Fosfatidilcolinas , Fosfatidilgliceroles , Unión Proteica , Estructura Terciaria de Proteína , Espectrometría de Fluorescencia , Espectrofotometría Infrarroja , Termodinámica

RESUMEN

The three-dimensional structure of the GroES monomer and its interaction with GroEL has been predicted using a combination of prediction tools and experimental data obtained by biophysical [electron microscope (EM), Fourier transform infrared (FTIR), and nuclear magnetic resonance (NMR)] and biochemical techniques. The GroES monomer, according to the prediction, is composed of eight beta-strands forming a beta-barrel with loose ends. In the model, beta-strands 5-8 run along the outer surface of GroES, forming an antiparallel beta-sheet with beta 4 loosely bound to one of the edges. beta-strands 1-3 would then be parallel and placed in the interior of the molecule. Loops 1-3 would face the internal cavity of the GroEL-GroES complex, and together with conserved residues in loops 5 and 7, would form the active surface interacting with GroEL.

Asunto(s)

Chaperonina 10/química , Chaperonina 60/metabolismo , Conformación Proteica , Secuencia de Aminoácidos , Sitios de Unión , Chaperonina 10/metabolismo , Chaperonina 60/química , Secuencia Conservada , Bases de Datos Factuales , Espectroscopía de Resonancia Magnética , Microscopía Electrónica , Modelos Moleculares , Datos de Secuencia Molecular , Mutación/genética , Pliegue de Proteína , Estructura Secundaria de Proteína , Proteínas Recombinantes/química , Espectroscopía Infrarroja por Transformada de Fourier

RESUMEN

The secondary structure of human apolipoprotein B at 37 degrees C is estimated to be 24% alpha-helix, 23% beta-sheet, 6% beta-turns, 24% unordered structure, and 24% "beta-strands," characterized by a band around 1618 cm-1, and consistent with extended string-like chains in contact with the lipid moiety not forming beta-sheets. When cooled to a temperature below the cholesteryl ester transition at 30 degrees C, the ordering of the low density lipoprotein core results in reversible changes in the protein conformation, decreasing the apparent amount of alpha-helix, beta-strand, and unordered structure below 30 degrees C and increasing beta-sheet and beta-turns. Lowering the ionic strength affects the core-associated transitions, shifting their temperature from 30 to 20 degrees C, and modifying protein conformation below the transition. An additional thermal event is observed at 75 degrees C, leading to irreversible protein denaturation. In the broad temperature range between the 30 and 75 degrees C transitions, apolipoprotein B is stable toward both temperature and ionic strength changes. After thermal denaturation, the protein retains a certain degree of ordered structure.

Asunto(s)

Apolipoproteínas B/química , Lipoproteínas LDL/química , Humanos , Concentración Osmolar , Estructura Secundaria de Proteína , Espectrofotometría Infrarroja , Temperatura

RESUMEN

The sensitivity of the keto and carbonyl infrared bands of daunomycin (DNM) to hydrogen bonding with the solvent, has been used to study the effect of the physical state and lipid composition of the bilayer on drug location. Our results show that penetration of daunomycin into dihexadecylphosphatidylcholine (Hxd2GroPCho) or dipalmitoylphosphatidylcholine bilayers, is dependent on the molecular packing of the lipid. DNM incorporates into the bilayer once the interdigitation of the gel phase of Hxd2GroPCho has been removed, above the pretransition temperature. Melting of the hydrocarbon chains of both lipids, at the main transition temperature, allows a similar and deeper drug penetration into the bilayers. Experiments using liposomes with different lipid compositions suggest that the relative concentration of certain lipids may modulate the location of DNM within the bilayer. Cholesterol, in a concentration-dependent manner, inhibits incorporation of anthracycline into apolar regions of the bilayer, while the presence of the negatively charged lipid dihexadecylphosphatidic acid is able to prevent the inhibitory effect of the steroid, allowing deeper penetration of the drug. Due to the importance of drug-membrane interactions in anthracycline cytotoxicity, the relevance of the observed differences in daunomycin location, caused by physical and/or chemical changes in the biological membranes, is discussed.

Asunto(s)

Daunorrubicina/química , Membrana Dobles de Lípidos/química , Lípidos de la Membrana/química , Colesterol/farmacología , Lípidos de la Membrana/análisis , Espectrofotometría Infrarroja , Temperatura

RESUMEN

It is described the case of an inflammatory maxillary sinus process, with both torpid evolution and post-traumatic etiology. The surgery proved the existence of a foreign body lodged in the maxillary sinus.

Asunto(s)

Cuerpos Extraños/complicaciones , Seno Maxilar , Sinusitis Maxilar/etiología , Adulto , Traumatismos Faciales/complicaciones , Cuerpos Extraños/etiología , Humanos , Masculino

RESUMEN

A case of rhinophyma, surgically treated, is reported, for being a process with low incidence and for its big size.

Asunto(s)

Rinofima/cirugía , Rinoplastia/métodos , Rosácea/cirugía , Humanos , Masculino , Persona de Mediana Edad , Rinofima/patología