RESUMEN

Insulin signalling in the brain plays an important role in the central regulation of energy homeostasis and fertility, such that mice exhibiting widespread deletion of insulin receptors (InsR) throughout the brain and peripheral nervous system display diet sensitive obesity and hypothalamic hypogonadism. However, the specific cell types mediating the central effects of insulin on fertility remain largely unidentified. To date, the targeted deletion of InsR from individual neuronal populations implicated in the metabolic control of fertility has failed to recapitulate the hypogonadic and subfertile phenotype observed in brain-specific InsR knockout mice. Because insulin and leptin share similar roles as centrally-acting metabolic regulators of fertility, we used the Cre-loxP system to generate mice with a selective inactivation of the Insr gene from the same widespread neuronal population previously shown to mediate the central effects of leptin on fertility by crossing Insr-flox mice with calcium/calmodulin-dependent protein kinase type IIα (CamkIIα)-Cre mice. Multiple reproductive and metabolic parameters were then compared between male and female Insr-flox/Cre-positive (CamK-IRKO) and Insr-flox/Cre-negative control mice. Consistent with brain-specific InsR knockout mice, CamK-IRKO mice exhibited a mild but significant obesogenic phenotype. Unexpectedly, CamK-IRKO mice exhibited normal reproductive maturation and function compared to controls. No differences in the age of puberty onset, oestrous cyclicity or fecundity were observed between CamK-IRKO and control mice. We conclude that the central effects of insulin on the neuroendocrine reproductive axis are not critically mediated via the same neuronal populations targeted by leptin.

Asunto(s)

Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/metabolismo , Insulina/fisiología , Neuronas/metabolismo , Reproducción/fisiología , Animales , Femenino , Insulina/farmacología , Leptina/farmacología , Masculino , Ratones , Ratones Noqueados , Obesidad/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Receptor de Insulina/biosíntesis , Receptor de Insulina/genética , Receptor de Insulina/fisiología , Reproducción/genética

RESUMEN

Insulin in the brain plays an important role in regulating reproductive function, as demonstrated via conditional brain-specific insulin receptor (Insr) deletion (knockout). However, the specific neuronal target cells mediating the central effects of insulin on the reproductive axis remain unidentified. We first investigated whether insulin can act via direct effects on gonadotrophin-releasing hormone (GnRH) neurones. After clearly detecting Insr mRNA in an immunopurified GnRH cell fraction, we confirmed the presence of insulin receptor protein (InsR) in approximately 82% of GnRH neurones using dual-label immunohistochemistry. However, we did not observe any insulin-induced phospho-Akt (pAkt) or phospho-extracellular-signal-regulated kinase 1/2 in GnRH neurones, and therefore we investigated whether insulin signals via kisspeptin neurones to modulate GnRH release. Using dual-label immunohistochemistry, InsRs were detected only in approximately 5% of kisspeptin-immunoreactive cells. Insulin-induced pAkt was not observed in any kisspeptin-immunoreactive cells in either the rostral periventricular region of the third ventricle or arcuate nucleus in response to 200 mU of insulin treatment, although a more pharmacological dose (10 U) induced pronounced (> 20%) pAkt-kisspeptin coexpression in both regions. To confirm that insulin signalling via kisspeptin neurones does not critically modulate reproductive function, we generated kisspeptin-specific InsR knockout (KIRKO) mice and assessed multiple reproductive and metabolic parameters. No significant differences in puberty onset, oestrous cyclicity or reproductive competency were observed in the female or male KIRKO mice compared to their control littermates. However, significantly decreased fasting insulin (P < 0.05) and a nonsignificant trend towards reduced body weight were observed in male KIRKO mice. Thus, InsR signalling in kisspeptin cells is not critical for puberty onset or reproductive competency, although it may have a small metabolic effect in males.

Asunto(s)

Fertilidad/fisiología , Hormona Liberadora de Gonadotropina/fisiología , Insulina/fisiología , Kisspeptinas/fisiología , Neuronas/fisiología , Animales , Femenino , Fertilidad/genética , Kisspeptinas/genética , Sistema de Señalización de MAP Quinasas/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteína Oncogénica v-akt/metabolismo , Receptor de Insulina/metabolismo , Transducción de Señal/fisiología

RESUMEN

Neuroinflammation in now established as an important factor in the pathogenesis of many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). At various time points, astrocytes and microglia are markedly activated, either producing neuroprotective or pro-inflammatory molecules, which can decrease or increase the rate of primary motor neuron degeneration respectively. Recent research has shown that this neuroinflammatory component is affected by the peripheral immune system; T lymphocytes in particular are able to cross into the brain and spinal cord parenchyma, where they interact with resident microglia, either inducing them to adopt an M1 (cytotoxic) or M2 (protective) phenotype, depending on the stage of disease. Clearly understanding the changes that occur to allow the interaction between peripheral and central immune responses will be essential in any attempt to manipulate the disease process via neuroinflammatory mechanisms. However, our understanding of the endothelial changes, which facilitate the infiltration of peripheral immune cells into the brain and spinal cord, is still in its infancy. There are suggestions, though, of up-regulation of cellular adhesion molecules, which are able to arrest circulating leukocytes and facilitate diapedesis into the brain parenchyma. In addition, tight junction proteins appear to be down-regulated, leading to an increase in vascular permeability, an effect that is amplified by vascular damage late in the disease process. This review summarises our current knowledge regarding neuroinflammation, peripheral immune involvement, and endothelial changes in ALS. This article is part of a Special Issue entitled 'Neuroinflammation in neurodegeneration and neurodysfunction'.

Asunto(s)

Esclerosis Amiotrófica Lateral/inmunología , Endotelio Vascular/inmunología , Inflamación/inmunología , Esclerosis Amiotrófica Lateral/patología , Animales , Astrocitos/inmunología , Moléculas de Adhesión Celular/inmunología , Moléculas de Adhesión Celular/metabolismo , Citocinas/inmunología , Endotelio Vascular/patología , Humanos , Inflamación/patología , Leucocitos/inmunología , Microglía/inmunología , Neuronas Motoras/inmunología , Linfocitos T/inmunología , Migración Transendotelial y Transepitelial

RESUMEN

A simple and high-throughput transposon mediated mutagenesis system employing in vitro shuttle transposon mutagenesis has been used to systematically mutagenise the Streptomyces coelicolor genome. To achieve the highest coverage, a new ordered cosmid library was also constructed. Individual cosmids from both the existing and new libraries were disrupted using the Tn5-based mini-transposon Tn5062. A total of 35,358 insertions were sequenced resulting in the disruption of 6,482 genes (83% of the predicted open reading frames). Complete information for both the newly generated cosmids as well as all the insertions has been uploaded onto a central database, StrepDB ( http://strepdb.streptomyces.org.uk/ ). All insertions, new cosmids and a range of transposon exchange cassettes are available for study of individual gene function.

Asunto(s)

Elementos Transponibles de ADN/genética , Mutagénesis Insercional/métodos , Streptomyces coelicolor/genética , Cósmidos/genética

RESUMEN

The characteristic Mn hyperfine 'multiline' signal exhibited in the S2 state of the oxygen-evolving complex (OEC) complex of Photosystem II (PSII) has been shown to be heterogeneous in character. In this study, we have explored the effects that influence the proportions of the two forms of the S2 state multiline signal present in any sample. The narrow form of the signal is lost upon storage (weeks) at 77 K, whereas the broad form remains. In particular, we explore the roles of ethanol and methanol as well as effects of the second turnover of the enzyme on storage of the sample at 77 K. We find that in samples containing methanol, the narrow form may predominate upon the first flash, but the broad form predominates on the fifth flash and also in samples containing ethanol.

Asunto(s)

Etanol/química , Metanol/química , Complejo de Proteína del Fotosistema II/química , Espectroscopía de Resonancia por Spin del Electrón , Manganeso/química , Manejo de Especímenes

RESUMEN

The interaction of water with the water oxidizing Mn complex of photosystem II has been investigated using electron spin-echo envelope modulation spectroscopy in the presence of H(2)(17)O. The spectra show interaction of the (17)O with the preparation in the S(2) state induced by 200 K illumination. The modulation is observed only in the center of the multiline spectrum. The inferred hyperfine coupling terms are compatible with water (not hydroxyl) oxygen bound to a particular quasi-axial Mn(III) center in a coupled Mn cluster.

Asunto(s)

Manganeso/química , Oxígeno/química , Complejo de Proteína del Fotosistema II/química , Agua/química , Adaptación Fisiológica , Sitios de Unión , Oscuridad , Espectroscopía de Resonancia por Spin del Electrón/métodos , Análisis de Fourier , Congelación , Ligandos , Isótopos de Oxígeno/química , Pisum sativum

Asunto(s)

Espectroscopía de Resonancia por Spin del Electrón/métodos , Proteínas del Complejo del Centro de Reacción Fotosintética/química , Clorofila/química , Transporte de Electrón , Radicales Libres , Complejos de Proteína Captadores de Luz , Estructura Molecular , Complejo de Proteína del Fotosistema I , Plastoquinona/química , Ubiquinona/química , Vitamina K 1/química

RESUMEN

Kinetic analysis using pulsed electron paramagnetic resonance (EPR) of photosynthetic electron transfer in the photosystem I reaction centres of Synechocystis 6803, in wild-type Chlamydomonas reinhardtii, and in site directed mutants of the phylloquinone binding sites in C. reinhardtii, indicates that electron transfer from the reaction centre primary electron donor, P700, to the iron-sulphur centres, Fe-S(X/A/B), can occur through either the PsaA or PsaB side phylloquinone. At low temperature reaction centres are frozen in states which allow electron transfer on one side of the reaction centre only. A fraction always donates electrons to the PsaA side quinone, the remainder to the PsaB side.

Asunto(s)

Complejos de Proteína Captadores de Luz , Proteínas de la Membrana/fisiología , Complejo de Proteína del Fotosistema I , Proteínas de Plantas/fisiología , Animales , Chlamydomonas reinhardtii/fisiología , Espectroscopía de Resonancia por Spin del Electrón , Radicales Libres , Oxidación-Reducción , Proteínas del Complejo del Centro de Reacción Fotosintética

RESUMEN

To investigate the environment of the phylloquinone secondary electron acceptor A(1) within the photosystem I reaction center, we have carried out site-directed mutagenesis of two tryptophan residues (W693 and W702) in the PsaA subunit of Chlamydomonas reinhardtii. One of these conserved tryptophans (W693) is predicted to be close to the phylloquinone and has been implicated in the interaction of A(1) with an aromatic residue through pi--pi stacking. We find that replacement of W702 with either histidine or leucine has no effect on the electronic structure of A(1)(*-) or on forward electron transfer from A(1)(*-) to the iron--sulfur center F(x). In contrast, the same mutations of W693 alter the electronic structure of the photoaccumulated A(1)(*-) and slow forward electron transfer as measured by the decay of the electron spin-polarized signal arising from the P700(*+)/A(1)(*-) radical pair. These results provide support for the hypothesis that W693 has a role in poising the redox potential of A(1)/A(1)(*-) so it can reduce F(x), and they indirectly provide evidence for electron transfer along the PsaA-side branch of cofactors in PSI.

Asunto(s)

Proteínas Bacterianas/genética , Chlamydomonas reinhardtii/metabolismo , Mutagénesis Sitio-Dirigida , Proteínas del Complejo del Centro de Reacción Fotosintética/genética , Proteínas del Complejo del Centro de Reacción Fotosintética/metabolismo , Complejo de Proteína del Fotosistema I , Proteínas Protozoarias , Triptófano/genética , Vitamina K 1/metabolismo , Secuencia de Aminoácidos , Animales , Benzoquinonas/metabolismo , Sitios de Unión/genética , Western Blotting , Chlamydomonas reinhardtii/genética , Chlamydomonas reinhardtii/crecimiento & desarrollo , Espectroscopía de Resonancia por Spin del Electrón , Transporte de Electrón , Radicales Libres/metabolismo , Proteínas de la Membrana/metabolismo , Datos de Secuencia Molecular , Fotoquímica , Proteínas del Complejo del Centro de Reacción Fotosintética/química , Proteínas de Plantas/metabolismo , Protones , Vitamina K 1/química

RESUMEN

OBJECTIVE: To examine the factors influencing the levels of sex hormone-binding globulin (SHBG) in normal postmenopausal women by assessing the relationship between SHBG and measured anthropometric, metabolic and hormonal variables. DESIGN: Cross-sectional, observational study. SUBJECTS AND METHODS: Seventy normal postmenopausal women aged 47-71 years (mean 58 years), participated in the study. Information was collected on medical, reproductive and smoking history, alcohol use, dietary intake and physical activity. Body composition measurements using dual-energy absorptiometry, and analyses of biochemical and hormonal indices were performed. RESULTS: Bivariate correlation coefficients indicated that SHBG was inversely related to body weight (r = - 0.44), fat mass (r = - 0.35), and abdominal obesity (r = - 0.42). It was also inversely related to the glucose and insulin levels during an oral glucose tolerance test (- 0.24 < r < - 0.40), serum oestradiol (r = - 0.26), and physical activity (r = - 0.24). Multiple regression analysis indicated that significant independent correlates of SHBG concentration were fat mass, physical activity, alcohol intake, serum oestradiol, and insulin-like growth factor-1, all having a negative impact on SHBG. CONCLUSIONS: From these observed associations, it is concluded that maintenance of body weight, moderate alcohol consumption, and physical activity will tend to reduce SHBG concentrations in postmenopausal women, thereby increasing the levels of free oestradiol. This mechanism could mediate the beneficial effects of these factors in preventing the development of osteoporosis and cardiovascular disease.

Asunto(s)

Posmenopausia/sangre , Globulina de Unión a Hormona Sexual/análisis , Anciano , Consumo de Bebidas Alcohólicas , Glucemia/análisis , Composición Corporal , Peso Corporal , Estudios Transversales , Estradiol/sangre , Ejercicio Físico , Femenino , Prueba de Tolerancia a la Glucosa , Humanos , Insulina/sangre , Factor I del Crecimiento Similar a la Insulina/análisis , Persona de Mediana Edad , Análisis de Regresión , Fumar

RESUMEN

This mini-review outlines the current theories on the mechanism of electron transfer from water to P680, the location and structure of the water oxidising complex and the role of the manganese cluster. We discuss how our data fit in with current theories and put forward our ideas on the location and mechanism of water oxidation.

Asunto(s)

Proteínas del Complejo del Centro de Reacción Fotosintética/química , Tirosina/análogos & derivados , Agua/química , Clorofila/química , Transporte de Electrón , Enlace de Hidrógeno , Ligandos , Complejos de Proteína Captadores de Luz , Manganeso/química , Estructura Molecular , Oxidación-Reducción , Oxígeno/química , Fotosíntesis , Protones , Tirosina/química

RESUMEN

PURPOSE: Thiazide diuretics reduce urine calcium excretion and might therefore reduce postmenopausal bone loss. In some, but not all, case-control studies, their use has been associated with a reduced incidence of hip fractures. We studied the effects of hydrochlorothiazide on bone loss in normal postmenopausal women. SUBJECTS AND METHODS: We performed a randomized, double-blind, 2-year trial of the effects of hydrochlorothiazide (50 mg per day) and placebo on bone mineral density in normal postmenopausal women. Participants were not required to have either low bone mineral density or hypertension. Bone mineral density was measured using dual-energy x-ray absorptiometry. RESULTS: One hundred eighty-five women entered the study, of whom 138 completed 2 years of follow-up. In an intention-to-treat analysis, hydrochlorothiazide produced significant benefits on bone mineral density of the total body (between-group difference at 2 years of 0.8%, 95% confidence interval [CI]: 0.3% to 1.3%, P <0.0001), legs (0.9%, 95% CI: 0.2% to 1.7%, P <0.0001), mid-forearm (1.2%, 95% CI: 0.2% to 2.2%, P = 0.02), and ultradistal forearm (1.7%, 95% CI: 0.1% to 3.2%, P = 0.04). There was no effect in the lumbar spine (0.5%, 95% CI: -0.5% to 1.6%) or femoral neck (0.2%, 95% CI: 1.3% to 1.7%). The between-group changes tended to be greatest during the first 6 months, except in the mid-forearm where there appeared to be a progressive divergence. An as-treated analysis produced similar results. Urine calcium excretion and indices of bone turnover decreased in the thiazide group, but parathyroid hormone concentrations did not differ between the groups. Treatment was tolerated well. CONCLUSIONS: Hydrochlorothiazide (50 mg per day) slows cortical bone loss in normal postmenopausal women. It may act directly on bone as well as on the renal tubule. The small size of the effect suggests that thiazides may have a role in the prevention of postmenopausal bone loss, but that they are not an appropriate monotherapy for treating osteoporosis.

Asunto(s)

Densidad Ósea/efectos de los fármacos , Calcio/metabolismo , Hidroclorotiazida/farmacología , Menopausia/metabolismo , Osteoporosis Posmenopáusica/prevención & control , Inhibidores de los Simportadores del Cloruro de Sodio/farmacología , Absorciometría de Fotón , Anciano , Diuréticos , Método Doble Ciego , Esquema de Medicación , Femenino , Cuello Femoral/metabolismo , Humanos , Hidroclorotiazida/administración & dosificación , Vértebras Lumbares/metabolismo , Persona de Mediana Edad , Osteoporosis Posmenopáusica/metabolismo , Valores de Referencia , Inhibidores de los Simportadores del Cloruro de Sodio/administración & dosificación , Factores de Tiempo , Resultado del Tratamiento

RESUMEN

We sought to identify and characterize the expression pattern of genes expressed by smooth muscle cells (SMCs) during periods of self-driven replication during vascular development and after vascular injury. Primary screening of a rat embryonic aortic SMC-specific cDNA library was accomplished with an autonomous embryonic SMC-enriched, nonautonomous adult SMC-subtracted cDNA probe. Positive clones were rescreened in parallel with embryonic SMC-specific and adult SMC-specific cDNA probes. We identified 14 clones that hybridized only with the embryonic cDNA ("emb" clones), 11 of which did not share significant homology with sequences in any of the databases. Five of these novel emb genes (emb7, emb8, emb20, emb37, and emb41) were selectively and only transiently reexpressed in vivo by neointimal SMCs during periods of rapid replication. The emb8:embryonic growth-associated protein (EGAP), which was studied the most extensively, was expressed at high levels by cultured, autonomously replicating embryonic and neointimal SMCs but was detected only at low levels even in mitogenically stimulated adult SMCs. Finally, the administration of antisense EGAP oligonucleotides markedly attenuated embryonic and neointimal SMC replication rates. We suggest that autonomous replication of SMCs may be essential for normal vascular morphogenesis and for the vascular response to injury and that these newly identified "embryonic" genes may be part of the molecular machinery that drives this unique growth phenotype.

Asunto(s)

Expresión Génica , Músculo Liso Vascular/citología , Neovascularización Fisiológica , Proteínas/genética , Animales , Aorta , División Celular/genética , Clonación Molecular , Embrión de Mamíferos/fisiología , Perfilación de la Expresión Génica , Masculino , Ratas , Ratas Sprague-Dawley

RESUMEN

BACKGROUND: Long-term treatment of patients with asymptomatic primary hyperparathyroidism remains controversial, but the presence of osteoporosis is regarded as an indication for parathyroidectomy. Hormone replacement therapy (HRT) is a possible alternative therapy in osteopenic postmenopausal women with the disorder, and results of short-term studies suggest a beneficial effect on bone mass comparable to that achieved by parathyroidectomy. Longer-term data are required to further assess the efficacy of this treatment in chronic stable primary hyperparathyroidism. METHODS: We report the results of the extension from 2 to 4 years of a randomized, placebo-controlled trial of HRT in postmenopausal women with primary hyperparathyroidism. Of 23 postmenopausal women with primary hyperparathyroidism, 11 received active HRT with conjugated equine estrogen, 0.625 mg/d, and medroxyprogesterone acetate, 5 mg/d, and 12 received placebo. Bone mineral density was measured throughout the skeleton at 6-month intervals using dual-energy x-ray absorptiometry in these women and in 50 normocalcemic age-matched control subjects. None of the 23 patients withdrew during the extension period. RESULTS: Changes in bone mineral density were more positive in those taking HRT than placebo, with the between-group differences at 4 years being 4.6% in the total body, 7.5% in the lumbar spine, 7.4% in the femoral neck, 8.2% in the femoral trochanter, 6.8% in the legs, and 7.0% in the forearm (P<.01). At skeletal sites composed predominantly of cortical bone, there was a progressive divergence of the 2 groups. Biochemical markers of bone turnover remained lower throughout the study in women taking HRT. When rates of bone loss were compared between the placebo group and healthy women of comparable age, bone loss tended to be more marked throughout the skeleton in women with hyperparathyroidism, but only in the total body and its legs subregion was this difference significant. CONCLUSIONS: Hormone replacement therapy is efficacious in the long-term management of osteopenia in postmenopausal women with primary hyperparathyroidism and thus represents an important new therapeutic option for asymptomatic patients who do not have other indications for surgery. Bone loss seems to be accelerated in untreated primary hyperparathyroidism.

Asunto(s)

Densidad Ósea/efectos de los fármacos , Estrógenos Conjugados (USP)/uso terapéutico , Terapia de Reemplazo de Hormonas , Hiperparatiroidismo/metabolismo , Acetato de Medroxiprogesterona/uso terapéutico , Osteoporosis Posmenopáusica/prevención & control , Posmenopausia , Absorciometría de Fotón , Anciano , Índice de Masa Corporal , Quimioterapia Combinada , Femenino , Estudios de Seguimiento , Humanos , Hiperparatiroidismo/complicaciones , Osteoporosis Posmenopáusica/etiología , Osteoporosis Posmenopáusica/metabolismo , Posmenopausia/efectos de los fármacos , Posmenopausia/metabolismo , Congéneres de la Progesterona/uso terapéutico , Resultado del Tratamiento

RESUMEN

The interaction of water oxidising photosystem II preparations with the aqueous environment has been investigated using electron spin echo envelope modulation spectroscopy in the presence of 2H(2)O. The spectra show interaction of 2H of 2H(2)O with the preparation in the S(2) state. The component interacting with water decays during 1-4 weeks storage at 77 K. No interaction of water with the classical multiline S(2) Mn signal, which is more stable on storage at 77 K, was detected. The results show that a component of the water oxidation complex, possibly involving the Mn centre, is accessible to water and may be the water binding site for photosynthetic water oxidation.

Asunto(s)

Manganeso/metabolismo , Proteínas del Complejo del Centro de Reacción Fotosintética/química , Proteínas del Complejo del Centro de Reacción Fotosintética/metabolismo , Pisum sativum/enzimología , Agua/metabolismo , Sitios de Unión , Oscuridad , Deuterio/metabolismo , Diurona/farmacología , Almacenaje de Medicamentos , Espectroscopía de Resonancia por Spin del Electrón , Estabilidad de Enzimas , Luz , Oxidantes/metabolismo , Oxidación-Reducción , Proteínas del Complejo del Centro de Reacción Fotosintética/antagonistas & inhibidores , Complejo de Proteína del Fotosistema II , Temperatura , Factores de Tiempo

RESUMEN

High rates of vascular smooth muscle cell (SMC) replication are observed, at least transiently, after injury to the arterial wall and contribute to the formation of a neointima. Neutralizing antibodies designed to inhibit growth of SMC have only been variably successful in inhibiting neointima formation, raising the possibility that neointimal cell proliferation involves unique growth mechanisms. This study examined the possibility that SMC isolated from injured rat carotid arteries would express an autonomous, mitogen-independent growth phenotype similar to that utilized by embryonic vascular SMC during periods of rapid growth. We found that primary cultures of SMC isolated 7 and 14 days after injury, times at which high in vivo replication rates were observed, demonstrated high intrinsic DNA synthetic rates compared to SMC isolated from uninjured arteries or at 2, 4, 21, and 28 days after injury where in vivo replication rates were far less. Subcultured SMC isolated from 7-day injured vessels (Neo7 SMC) exhibited a stable, autonomous growth phenotype, did not secrete detectable mitogenic activity, and had decreased alpha-actin and myosin expression compared to mitogen-dependent SMC. Heterokaryons constructed between autonomous Neo7 SMC and mitogen-dependent SMC exhibited a mitogen-dependent growth phenotype suggesting that nonautonomous SMC produce factors that actively inhibit autonomous growth. In contrast, heterokaryons constructed between Neo7 SMC and autonomous embryonic SMC retained an autonomous growth phenotype. We examined the expression of known tumor suppressors to determine if any of these factors played a role in inhibiting SMC autonomous growth. p27, p53, pRb, and PTEN were abundantly expressed by Neo7 SMC and e17 SMC under both basal and serum stimulated conditions. The data suggest that the mechanisms driving SMC replication during neointimal formation are self-driven and self-regulated, and that at specific times after injury, SMC escape normal growth suppressive mechanisms through the loss of intracellular growth suppressor activity.

Asunto(s)

Traumatismos de las Arterias Carótidas/patología , Músculo Liso Vascular/citología , Túnica Íntima/citología , Animales , Aorta/citología , Aorta/efectos de los fármacos , Aorta/embriología , Aorta/crecimiento & desarrollo , Traumatismos de las Arterias Carótidas/metabolismo , Cateterismo , División Celular/efectos de los fármacos , Fusión Celular , Tamaño de la Célula/efectos de los fármacos , Células Cultivadas , Proteínas Contráctiles/genética , Proteínas Contráctiles/metabolismo , Medios de Cultivo Condicionados/química , Medios de Cultivo Condicionados/farmacología , Femenino , Genes Supresores de Tumor/fisiología , Sustancias de Crecimiento/análisis , Sustancias de Crecimiento/farmacología , Masculino , Músculo Liso Vascular/embriología , Músculo Liso Vascular/lesiones , Músculo Liso Vascular/metabolismo , Fenotipo , Antígeno Nuclear de Célula en Proliferación/metabolismo , ARN Mensajero/análisis , ARN Mensajero/genética , Ratas , Ratas Sprague-Dawley , Túnica Íntima/efectos de los fármacos , Túnica Íntima/lesiones , Túnica Íntima/metabolismo

RESUMEN

A behavioral model of dopaminergic function in the rat was used to examine the anticataleptic effects of L-prolyl-L-leucyl-glycinamide (PLG) and peptidomimetic analogs of PLG. Administration of 1 mg/kg PLG intraperitoneally significantly attenuated haloperidol (1 mg/kg)-induced catalepsy (as measured by the standard horizontal bar test), whereas doses of 0.1 and 10 mg/kg PLG did not. Eight synthetic PLG peptidomimetics (Calpha, alpha-dialkylated glycyl residues with lactam bridge constraint [1-4] and without [5-8]) were tested in the same manner (at a dose of 1 microg/kg) and categorized according to their activity, i.e. very active (5), moderately active (2, 3, 4, and 6), and inactive (1, 7, and 8). The catalepsy-reversal action of the diethylglycine-substituted peptidomimetic 5 was examined further and found to exhibit a U-shaped dose-response effect with an optimal dose of 1 microg/kg. The similarity between the effects of PLG and the synthetic peptidomimetics suggests a common mechanism of action. Finally, the synthetic peptidomimetics examined here, particularly peptidomimetic 5, were more effective than PLG in attenuating haloperidol-induced catalepsy.

Asunto(s)

Catalepsia/tratamiento farmacológico , Haloperidol/efectos adversos , Hormona Inhibidora de la Liberación de MSH/farmacología , Imitación Molecular , Animales , Catalepsia/inducido químicamente , Relación Dosis-Respuesta a Droga , Hormona Inhibidora de la Liberación de MSH/química , Hormona Inhibidora de la Liberación de MSH/uso terapéutico , Masculino , Ratas , Ratas Sprague-Dawley

RESUMEN

Part 1: A Clinical Review: Fractures of the olecranon in children are uncommon, and the outcome has historically been reported as good. Management varies from simple immobilization to include various methods of internal fixation. Recently a new technique of fracture fixation has been used in an attempt to improve the management of this fracture. This article reviews olecranon fractures seen at two children's hospitals over a 10-year period. The purpose of the study was to review and classify various fracture patterns, different fixation techniques, and to assess medium-term outcomes after this uncommon injury. Part 2: A New Classification and Management Algorithm: A new classification system and management algorithm for fractures of the olecranon in children is presented. This was developed after a 10-year review of olecranon fractures and their management at two children's hospitals (Part 1). Minimally displaced or undisplaced fractures account for 80% of all olecranon fractures, and these are managed with immobilization, rarely requiring hospital admission. Of those fractures admitted to hospital, oblique metaphyseal fractures are most commonly seen and are satisfactorily treated with tension-band techniques, but a wide variety of fracture patterns are less common and may require different management. Previous classifications of this uncommon fracture have not addressed all of the significant features to categorize the fracture accurately or to imply a management pathway. This new anatomically based classification system facilitates accurate classification for research purposes, and its principles are applied in the clinical-management algorithm presented here.

Asunto(s)

Lesiones de Codo , Fijación Interna de Fracturas , Fracturas Óseas/cirugía , Adolescente , Algoritmos , Niño , Preescolar , Codo/diagnóstico por imagen , Femenino , Fracturas Óseas/clasificación , Fracturas Óseas/diagnóstico por imagen , Humanos , Lactante , Masculino , Radiografía , Estudios Retrospectivos , Técnicas de Sutura , Resultado del Tratamiento

RESUMEN

Photoaccumulation at 205 K in the presence of dithionite produces EPR signals in anaerobically prepared membranes from Chlorobium limicola and Heliobacterium chlorum that resemble the EPR spectrum of phyllosemiquinone (A1*-) photoaccumulated in photosystem I. We have used ENDOR and special TRIPLE resonance spectroscopy to demonstrate conclusively that these signals arise from menasemiquinone electron acceptors reduced by photoaccumulation. Hyperfine couplings to two protons H-bonded to the semiquinone oxygens have been identified by exchange of H. chlorum into D2O, and hyperfine couplings to the methyl group, and the methylene group of the phytyl side chain, of the semiquinone have also been assigned. The electronic structure of these menasemiquinones in these reaction centers is very similar to that of phyllosemiquinone in PSI, and shows a distorted electron spin density distribution relative to that of phyllosemiquinone in vitro. Special TRIPLE resonance spectrometry has been used to investigate the effect of detergents and oxygen on membranes of C. limicola. Triton X-100 and oxygen affect the menaquinone binding site, but n-dodecyl beta-D-maltoside preparations exhibit a relatively unaltered special TRIPLE spectrum for the photoaccumulated menasemiquinone.

Asunto(s)

Chlorobi/química , Electrones , Proteínas del Complejo del Centro de Reacción Fotosintética/química , Plastoquinona/análogos & derivados , Bacterias/química , Benzoquinonas/química , Membrana Celular/química , Ditionita , Espectroscopía de Resonancia por Spin del Electrón/métodos , Enlace de Hidrógeno , Octoxinol , Oxígeno/toxicidad , Fotoquímica , Fotosíntesis/efectos de los fármacos , Plastoquinona/química , Protones

RESUMEN

Interaction of the water oxidising manganese complex of photosystem II with the aqueous environment has been investigated using electron paramagnetic resonance spectroscopy and electron spin echo envelope modulation spectroscopy to detect interaction of [2H]methanol with the complex in the S2 state. The experiments show that the classical S2 multiline signal is associated with a manganese environment which is not exposed to the aqueous medium. An electron paramagnetic resonance spectroscopy signal, also induced by 200 K illumination, showing 2H modulation by methanol in the medium and a modified multiline electron paramagnetic resonance spectroscopy signal formed in parallel to it, are suggested to be associated with a second manganese environment exposed to the medium.

Asunto(s)

Manganeso/metabolismo , Proteínas del Complejo del Centro de Reacción Fotosintética/metabolismo , Agua/metabolismo , Espectroscopía de Resonancia por Spin del Electrón , Oxidación-Reducción , Complejo de Proteína del Fotosistema II , Solventes