RESUMEN

BACKGROUND: In Sweden, home care services is a major external contact for older persons. METHODS: Five home care service companies in Stockholm, Sweden, enrolled 405 employees to a study including serum IgG to SARS-CoV-2 and SARS-CoV-2 virus in throat swabs. RESULTS: 20.1% (81/403) of employees were seropositive, about twice as many as in a simultaneously enrolled reference population (healthcare workers entirely without patient contact, n = 3671; 9.7% seropositivity). 13/379 employees (3.4%) had a current infection (PCR positivity). Amongst these, 5 were also seropositive and 3 were positive with low amounts of virus. High amounts of virus and no antibodies (a characteristic for presymptomatic COVID-19) were present in 5 employees (1.3%). CONCLUSIONS: Personnel providing home services for older persons appear to be a risk group for SARS-CoV-2. Likely presymptomatic employees can be readily identified by screening. Increased protection of employees and of the older persons they serve is warranted.

Asunto(s)

COVID-19/epidemiología , Personal de Salud/estadística & datos numéricos , Servicios de Atención de Salud a Domicilio , Adulto , Anciano , Anticuerpos Antivirales/sangre , COVID-19/diagnóstico , Femenino , Humanos , Inmunoglobulina G/sangre , Masculino , Faringe/virología , ARN Viral/análisis , Reacción en Cadena en Tiempo Real de la Polimerasa , SARS-CoV-2 , Suecia/epidemiología

RESUMEN

BACKGROUND: Free flap complications are generally rare, but not negligible since they may exert paramount impact on both patients and care providers. The aim of the study was to identify risk factors for reexploration and assess predictors associated with increased salvage rates. METHODS: A retrospective cohort study was conducted for free flaps performed between 2006 and 2015. Patient demographics, indications and flap types were analyzed together with complications and time to reexploration. RESULTS: Among 547 consecutive free flaps, 11.5% required acute reexploration. Hematoma together with vascular compromise was the main cause (41.9%) for reexploration, followed by hematoma only (19.4%), venous (16.1%) and arterial (6.5%) thrombosis. Hematoma was associated with an increased risk for concomitant vascular complication (p < 0.02). The incidence of total and partial flap necrosis was 3.5% and 3.7% respectively. There was an overall 71.4% salvage rate. The median time from detection of a compromised flap to reexploration was 3.0 h. Significantly higher salvage rates were observed for cases reexplored within (82.4%) compared to after (57.1%) 3.0 h (OR 3.50 (95% CI 1.10 to 11.13, p = 0.034)). CONCLUSIONS: The current study highlights the importance of early intervention, including evacuation of hematomas that may lead to vascular compromise. Adequate monitoring of venous outflow was found necessary to improve flap salvage rates, whereas arterial complications were mainly related to persistent arterial injury in traumatized extremities with reduced salvage rates. Free flap surgery requires trained staff and immediate access to operating facilities to ensure high flap survival rates.

Asunto(s)

Colgajos Tisulares Libres , Hematoma , Procedimientos de Cirugía Plástica/efectos adversos , Complicaciones Posoperatorias , Trombosis , Intervención Médica Temprana/métodos , Femenino , Colgajos Tisulares Libres/efectos adversos , Colgajos Tisulares Libres/irrigación sanguínea , Colgajos Tisulares Libres/clasificación , Colgajos Tisulares Libres/estadística & datos numéricos , Hematoma/etiología , Hematoma/prevención & control , Hematoma/cirugía , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/patología , Complicaciones Posoperatorias/fisiopatología , Complicaciones Posoperatorias/cirugía , Procedimientos de Cirugía Plástica/métodos , Flujo Sanguíneo Regional , Reoperación/métodos , Reoperación/estadística & datos numéricos , Estudios Retrospectivos , Ajuste de Riesgo/métodos , Factores de Riesgo , Terapia Recuperativa/métodos , Suecia/epidemiología , Trombosis/etiología , Trombosis/prevención & control , Trombosis/cirugía , Tiempo de Tratamiento/estadística & datos numéricos

RESUMEN

Emerging evidence suggests that inflammation has a key role in depression and suicidal behavior. The kynurenine pathway is involved in neuroinflammation and regulates glutamate neurotransmission. In the cerebrospinal fluid (CSF) of suicidal patients, levels of inflammatory cytokines and the kynurenine metabolite quinolinic acid (QUIN), an N-methyl-d-aspartate receptor agonist, are increased. The enzyme amino-ß-carboxymuconate-semialdehyde-decarboxylase (ACMSD) limits QUIN formation by competitive production of the neuroprotective metabolite picolinic acid (PIC). Therefore, decreased ACMSD activity can lead to excess QUIN. We tested the hypothesis that deficient ACMSD activity underlies suicidal behavior. We measured PIC and QUIN in CSF and plasma samples from 137 patients exhibiting suicidal behavior and 71 healthy controls. We used DSM-IV and the Montgomery-Åsberg Depression Rating Scale and Suicide Assessment Scale to assess behavioral changes. Finally, we genotyped ACMSD tag single-nucleotide polymorphisms (SNPs) in 77 of the patients and 150 population-based controls. Suicide attempters had reduced PIC and a decreased PIC/QUIN ratio in both CSF (P<0.001) and blood (P=0.001 and P<0.01, respectively). The reductions of PIC in CSF were sustained over 2 years after the suicide attempt based on repeated measures. The minor C allele of the ACMSD SNP rs2121337 was more prevalent in suicide attempters and associated with increased CSF QUIN. Taken together, our data suggest that increased QUIN levels may result from reduced activity of ACMSD in suicidal subjects. We conclude that measures of kynurenine metabolites can be explored as biomarkers of suicide risk, and that ACMSD is a potential therapeutic target in suicidal behavior.

Asunto(s)

Carboxiliasas/genética , Ácidos Picolínicos/líquido cefalorraquídeo , Ácido Quinolínico/líquido cefalorraquídeo , Conducta Autodestructiva/genética , Ideación Suicida , Intento de Suicidio , Adolescente , Adulto , Anciano , Alelos , Estudios de Casos y Controles , Niño , Femenino , Humanos , Inflamación , Quinurenina/metabolismo , Masculino , Persona de Mediana Edad , Ácidos Picolínicos/sangre , Polimorfismo de Nucleótido Simple , Ácido Quinolínico/sangre , Conducta Autodestructiva/sangre , Conducta Autodestructiva/líquido cefalorraquídeo , Adulto Joven

RESUMEN

Using specific riboprobes, we characterized the expression of vesicular glutamate transporter (VGLUT)1-VGLUT3 transcripts in lumbar 4-5 (L4-5) dorsal root ganglions (DRGs) and the thoracolumbar to lumbosacral spinal cord in male BALB/c mice after a 1- or 3-day hindpaw inflammation, or a 7-day sciatic nerve axotomy. Sham animals were also included. In sham and contralateral L4-5 DRGs of injured mice, VGLUT1-, VGLUT2- and VGLUT3 mRNAs were expressed in ∼45%, ∼69% or ∼17% of neuron profiles (NPs), respectively. VGLUT1 was expressed in large and medium-sized NPs, VGLUT2 in NPs of all sizes, and VGLUT3 in small and medium-sized NPs. In the spinal cord, VGLUT1 was restricted to a number of NPs at thoracolumbar and lumbar segments, in what appears to be the dorsal nucleus of Clarke, and in mid laminae III-IV. In contrast, VGLUT2 was present in numerous NPs at all analyzed spinal segments, except the lateral aspects of the ventral horns, especially at the lumbar enlargement, where it was virtually absent. VGLUT3 was detected in a discrete number of NPs in laminae III-IV of the dorsal horn. Axotomy resulted in a moderate decrease in the number of DRG NPs expressing VGLUT3, whereas VGLUT1 and VGLUT2 were unaffected. Likewise, the percentage of NPs expressing VGLUT transcripts remained unaltered after hindpaw inflammation, both in DRGs and the spinal cord. Altogether, these results confirm previous descriptions on VGLUTs expression in adult mice DRGs, with the exception of VGLUT1, whose protein expression was detected in a lower percentage of mouse DRG NPs. A detailed account on the location of neurons expressing VGLUTs transcripts in the adult mouse spinal cord is also presented. Finally, the lack of change in the number of neurons expressing VGLUT1 and VGLUT2 transcripts after axotomy, as compared to data on protein expression, suggests translational rather than transcriptional regulation of VGLUTs after injury.

Asunto(s)

Ganglios Espinales/metabolismo , Neuronas/metabolismo , Médula Espinal/metabolismo , Proteínas de Transporte Vesicular de Glutamato/metabolismo , Sistemas de Transporte de Aminoácidos Acídicos/análisis , Sistemas de Transporte de Aminoácidos Acídicos/metabolismo , Animales , Axotomía , Miembro Posterior , Inflamación/metabolismo , Masculino , Ratones , Ratones Endogámicos BALB C , ARN Mensajero/metabolismo , Nervio Ciático/lesiones , Proteína 1 de Transporte Vesicular de Glutamato/análisis , Proteína 1 de Transporte Vesicular de Glutamato/metabolismo , Proteína 2 de Transporte Vesicular de Glutamato/análisis , Proteína 2 de Transporte Vesicular de Glutamato/metabolismo , Proteínas de Transporte Vesicular de Glutamato/análisis

RESUMEN

BACKGROUND: Hypoxia is an element of the tumour microenvironment that impacts upon numerous cellular factors linked to clinical aggressiveness in cancer. One such factor, Snail, a master regulator of the epithelial-mesenchymal transition (EMT), has been implicated in key tumour biological processes such as invasion and metastasis. In this study we set out to investigate regulation of EMT in hypoxia, and the importance of Snail in cell migration and clinical outcome in breast cancer. METHODS: Four breast cancer cell lines were exposed to 0.1% oxygen and expression of EMT markers was monitored. The migratory ability was analysed following Snail overexpression and silencing. Snail expression was assessed in 500 tumour samples from premenopausal breast cancer patients, randomised to either 2 years of tamoxifen or no adjuvant treatment. RESULTS: Exposure to 0.1% oxygen resulted in elevated levels of Snail protein, along with changes in vimentin and E-cadherin expression, and in addition increased migration of MDA-MB-468 cells. Overexpression of Snail increased the motility of MCF-7, T-47D and MDA-MB-231 cells, whereas silencing of the protein resulted in decreased migratory propensity of MCF-7, MDA-MB-468 and MDA-MB-231 cells. Moreover, nuclear Snail expression was associated with tumours of higher grade and proliferation rate, but not with disease recurrence. Interestingly, Snail negativity was associated with impaired tamoxifen response (P=0.048). CONCLUSIONS: Our results demonstrate that hypoxia induces Snail expression but generally not a migratory phenotype, suggesting that hypoxic cells are only partially pushed towards EMT. Furthermore, our study supports the link between Snail and clinically relevant features and treatment response.

Asunto(s)

Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Factores de Transcripción/biosíntesis , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Western Blotting , Procesos de Crecimiento Celular/fisiología , Hipoxia de la Célula/fisiología , Línea Celular Tumoral , Movimiento Celular/genética , Movimiento Celular/fisiología , Supervivencia sin Enfermedad , Células Epiteliales/patología , Femenino , Humanos , Inmunohistoquímica , Estimación de Kaplan-Meier , Mesodermo/patología , Oxígeno/administración & dosificación , Oxígeno/metabolismo , Transducción de Señal , Factores de Transcripción de la Familia Snail , Tamoxifeno/farmacología , Factores de Transcripción/genética , Transfección

RESUMEN

Decreased availability or efficacy of neurotrophic factors may underlie an increased susceptibility of mesencephalic dopaminergic cells to age-related degeneration. Neuregulins (NRGs) are pleotrophic growth factors for many cell types, including mesencephalic dopamine cells in culture and in vivo. The functional NRG receptor ErbB4 is expressed by virtually all midbrain dopamine neurons. To determine if levels of the NRG receptor are maintained during aging in the dopaminergic ventral mesencephalon, expression of ErbB4 mRNA and protein was examined in young (3 months), middle-aged (18 months), and old (24-25 months) Brown Norway/Fischer 344 F1 rats. ErbB4 mRNA levels in the substantia nigra pars compacta (SNpc), but not the adjacent ventral tegmental area (VTA) or subtantia nigra pars lateralis (SNl), were significantly reduced in the middle-aged and old animals when compared to young rats. Protein expression of ErbB4 in the ventral midbrain was significantly decreased in the old rats when compared to the young rats. Expression of tyrosine hydroxylase (TH) mRNA levels was significantly reduced in the old rats when compared to young animals in the SNpc, but not in the VTA or SNI. TH protein levels in the ventral midbrain were also decreased in the old animals when compared to the young animals. These data demonstrate a progressive decline of ErbB4 expression, coinciding with a loss of the dopamine-synthesizing enzyme TH, in the ventral midbrain of aged rats, particularly in the SNpc. These findings may implicate a role for diminished NRG/ErbB4 trophic support in dopamine-related neurodegenerative disorders of aging such as Parkinson's disease.

Asunto(s)

Envejecimiento/metabolismo , Dopamina/biosíntesis , Receptores ErbB/metabolismo , Sustancia Negra/metabolismo , Tirosina 3-Monooxigenasa/metabolismo , Área Tegmental Ventral/metabolismo , Envejecimiento/genética , Animales , Supervivencia Celular/genética , Regulación hacia Abajo/genética , Receptores ErbB/genética , Regulación de la Expresión Génica/fisiología , Masculino , Degeneración Nerviosa/genética , Degeneración Nerviosa/metabolismo , Degeneración Nerviosa/fisiopatología , Enfermedad de Parkinson/genética , Enfermedad de Parkinson/metabolismo , Enfermedad de Parkinson/fisiopatología , ARN Mensajero/metabolismo , Ratas , Ratas Endogámicas F344 , Receptor ErbB-4 , Sustancia Negra/citología , Tirosina 3-Monooxigenasa/genética , Área Tegmental Ventral/citología

RESUMEN

Hypoxia affects many important processes in tumour progression and is a key feature in the tumour microenvironment that needs to be taken into account when evaluating prognostics and therapeutic options for cancer patients. Hypoxia-regulating proteins, i.e. hypoxia inducible factors (HIFs), and associated gene products have been linked to certain tumour behaviours and might be useful as prognostic and predictive markers. Recently, hypoxia-driven gene products have been launched as novel cancer treatment targets with the potential to increase tumour-specific effects. Breast cancer consists of a multitude of different diseases with certain common characteristics, but also clearly disparate behaviours and genetic alterations. In this review we will summarise the role of hypoxia in breast cancer and specifically outline the importance of hypoxia and HIF-1alpha regarding prognostic and treatment-specific implications. (Part of a Multi-author Review).

Asunto(s)

Neoplasias de la Mama/diagnóstico , Neoplasias de la Mama/terapia , Hipoxia de la Célula/fisiología , Biomarcadores Farmacológicos/metabolismo , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Hipoxia de la Célula/genética , Receptor alfa de Estrógeno/genética , Receptor alfa de Estrógeno/fisiología , Regulación Neoplásica de la Expresión Génica , Humanos , Factor 1 Inducible por Hipoxia/genética , Modelos Biológicos , Pronóstico

RESUMEN

It has been proposed that the glycogenolytic and gluconeogenic pathways contributing to endogenous glucose production are interrelated. Thus a change in one source of glucose 6-phosphate might be compensated for by an inverse change in the other pathway. We therefore investigated the effects of 1,4-dideoxy-1,4-imino-D-arabinitol (DAB), a potent glycogen phosphorylase inhibitor, on glucose production in fasted conscious dogs. When dogs were treated acutely with high glucagon, glucose production rose from 1.93 +/- 0.14 to 3.07 +/- 0.37 mg x kg(-1) x min(-1) (P < 0.01). When dogs were treated acutely with DAB in addition to high glucagon infusion, the stimulation of the glycogenolytic rate was completely suppressed. Glucose production rose from 1.85 +/- 0.20 to 2.41 +/- 0.17 mg x kg(-1) x min(-1) (P < 0.05), which was due to the increase in gluconeogenesis from 0.93 +/- 0.09 to 1.54 +/- 0.08 mg x kg(-1) x min(-1) (P < 0.001). In conclusion, infusion of DAB inhibited glycogenolysis; however, the absolute contribution of gluconeogenesis to glucose production was not affected. These results suggest that inhibition of glycogenolysis could be an effective antidiabetic treatment.

Asunto(s)

Glucógeno/metabolismo , Hígado/metabolismo , Animales , Arabinosa , Glucemia/efectos de los fármacos , Perros , Inhibidores Enzimáticos/farmacología , Glucagón/administración & dosificación , Gluconeogénesis/efectos de los fármacos , Técnica de Clampeo de la Glucosa , Hidrólisis/efectos de los fármacos , Iminofuranosas , Infusiones Intravenosas , Hígado/efectos de los fármacos , Masculino , Fosforilasas/antagonistas & inhibidores , Vena Porta , Alcoholes del Azúcar/administración & dosificación

RESUMEN

The first synthesis of the single isomers (3R,4R,5R); (3S,4S,5S): (3R,4R,5S) and (3S,4S,5R) of 5-hydroxymethyl-piperidine-3,4-diol from Arecolin is reported, including the synthesis of a series of N-substituted derivatives of the (3R,4R,5R)-isomer (Isofagomine). The inhibitory effect of these isomers as well as of a series of N-substituted derivatives of the (3R,4R,5R)-isomer and selected hydroxypiperidine analogues on liver glycogen phosphorylase (GP) showed that the (3R,4R,5R) configuration was essential for obtaining an inhibitory effect at submicromolar concentration. The results also showed that all three hydroxy groups should be present and could not be substituted, nor were extra OH groups allowed if sub-micromolar inhibition should be obtained. Some inhibitory effect was retained for N-substituted derivatives of Isofagomine; however, N-substitution always resulted in a loss of activity compared to the parent compound, IC50 values ranging from 1 to 100 microM were obtained for simple alkyl, arylalkyl and benzoylmethyl substituents. Furthermore, we found that it was not enough to assure inhibitory effect to have the (R,R,R) configuration. Fagomine, the (2R,3R,4R)-2-hydroxymethylpiperidine-3,4-diol analogue, showed an IC50 value of 200 microM compared to 0.7 microM for Isofagomine. In addition, Isofagomine was able to prevent basal and glucagon stimulated glycogen degradation in cultured hepatocytes with IC50 values of 2-3 microM.

Asunto(s)

Carbohidratos/farmacología , Fosforilasas/antagonistas & inhibidores , Piperidinas/síntesis química , Animales , Metabolismo de los Hidratos de Carbono , Carbohidratos/síntesis química , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Iminas/síntesis química , Iminas/farmacología , Iminopiranosas , Concentración 50 Inhibidora , Hígado/enzimología , Piperidinas/química , Piperidinas/farmacología , Conejos , Ratas , Estereoisomerismo , Relación Estructura-Actividad , Porcinos

Asunto(s)

Penicilina V , Penicilinas , Historia del Siglo XX , Humanos , Resistencia a las Penicilinas , Penicilina V/administración & dosificación , Penicilina V/historia , Penicilinas/administración & dosificación , Penicilinas/historia , Guías de Práctica Clínica como Asunto , Suecia

RESUMEN

The effects of 1,4-dideoxy-1,4-imino-d-arabinitol (DAB) were investigated on preparations of glycogen phosphorylase (GP) and in C57BL6J (ob/ob) mice by (13)C NMR in vivo. Independent of the phosphorylation state or the mammalian species or tissue from which GP was derived, DAB inhibited GP with K(i)-values of approximately 400 nM. The mode of inhibition was uncompetitive or noncompetitive, with respect to glycogen and P(i), respectively. The effects of glucose and caffeine on the inhibitory effect of DAB were investigated. Taken together, these data suggest that DAB defines a novel mechanism of action. Intraperitoneal treatment with DAB (a total of 105 mg/kg in seven doses) for 210 min inhibited glucagon-stimulated glycogenolysis in obese and lean mice. Thus, liver glycogen levels were 361 +/- 19 and 228 +/- 19 micromol glucosyl units/g with DAB plus glucagon in lean and obese mice, respectively, compared to 115 +/- 24 and 37 +/- 8 micromol glucosyl units/g liver with glucagon only. Moreover, with glucagon only end-point blood glucose levels were at 29 +/- 2 and 17.5 +/- 2 mM in obese and lean mice, respectively, compared to 17.5 +/- 1 and 12 +/- 1 mM with glucagon plus DAB. In conclusion, DAB is a novel and potent inhibitor of GP with an apparently distinct mechanism of action. Further, DAB inhibited the hepatic glycogen breakdown in vivo and displayed an accompanying anti-hyperglycemic effect, which was most pronounced in obese mice. The data suggest that inhibition of GP may offer a therapeutic principle in Type 2 diabetes.

Asunto(s)

Inhibidores Enzimáticos/farmacología , Hipoglucemiantes/farmacología , Fosforilasas/antagonistas & inhibidores , Alcoholes del Azúcar/farmacología , Animales , Arabinosa , Glucemia/metabolismo , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Femenino , Glucagón/farmacología , Glucógeno/metabolismo , Iminofuranosas , Técnicas In Vitro , Cinética , Ácido Láctico/sangre , Hígado/enzimología , Espectroscopía de Resonancia Magnética , Ratones , Ratones Endogámicos C57BL , Ratones Obesos , Músculos/enzimología , Conejos , Ratas , Porcinos

RESUMEN

The checkpoint kinase Chk1 is an important mediator of cell cycle arrest following DNA damage. The 1.7 A resolution crystal structures of the human Chk1 kinase domain and its binary complex with an ATP analog has revealed an identical open kinase conformation. The secondary structure and side chain interactions stabilize the activation loop of Chk1 and enable kinase activity without phosphorylation of the catalytic domain. Molecular modeling of the interaction of a Cdc25C peptide with Chk1 has uncovered several conserved residues that are important for substrate selectivity. In addition, we found that the less conserved C-terminal region negatively impacts Chk1 kinase activity.

Asunto(s)

Ciclo Celular/fisiología , Proteínas Quinasas/química , Proteínas Quinasas/metabolismo , Dominio Catalítico , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Secuencia Conservada , Cristalografía , Activación Enzimática/fisiología , Células Eucariotas/citología , Células Eucariotas/enzimología , Humanos , Datos de Secuencia Molecular , Fosforilación , Estructura Terciaria de Proteína , Homología de Secuencia de Aminoácido , Especificidad por Sustrato

RESUMEN

BACKGROUND/PURPOSE: Interleukin-11 (IL-11) recently has been shown to enhance mucosal mass after massive small bowel resection (MSBR). However, enhanced mucosal mass may not correlate with increased substrate absorption. This study was designed to examine the effect of systemic administration of increasing doses of IL-11 on small intestine absorptive function and mucosal mass after MSBR. METHODS: Twenty-five Sprague-Dawley rats underwent an 80% small bowel resection and end-to-end jejunoileal anastomosis. Seven days after resection, all rats had placement of a jugular venous catheter connected to a subcutaneously placed osmotic pump. The rats were divided into 5 groups based on the content of the pump: group 1 (control, n = 5) received 0.1% bovine serum albumin (BSA) and groups 2 through 5 (n = 5 each) received IL-11 at 250, 500, 750, and 1,000 microg/kg/d, respectively. After a 14-day infusion period, [14C] galactose and [14C] glycine absorption was measured using an in vivo closed-recirculation technique. Mucosal DNA content also was determined for each group. Statistical analysis was performed by analysis of variance and expressed as mean +/-SEM. RESULTS: IL-11 administered at 250 microg/kg/d, a dose used in previous studies, did not significantly affect substrate absorption. However, compared with the control group, administration of higher doses of IL-11 produced a significant increase in substrate absorption and mucosal mass. The dose of IL-11 producing the overall optimal response based on the parameters measured (galactose absorption, 72% increase over control; glycine absorption, 112% increase over control; and DNA content, 98% increase over control) was 750 microg/kg/d. CONCLUSIONS: In addition to an increase in mucosal mass, these data show for the first time that IL-11 enhances absorptive function beyond the normal adaptive response after MSBR. Furthermore, the maximum effect of IL-11 on absorptive function was shown at 750 microg/kg/d, which is 3 times the dose used in previously reported studies. This study suggests that IL-11 may be useful clinically in patients with inadequate intestinal function.

Asunto(s)

Adaptación Fisiológica , Interleucina-11/fisiología , Absorción Intestinal/fisiología , Mucosa Intestinal/fisiología , Animales , Modelos Animales de Enfermedad , Humanos , Masculino , Ratas , Ratas Sprague-Dawley , Síndrome del Intestino Corto/fisiopatología

RESUMEN

A combinatorial library of 125 compounds with a structure consisting of 1-azafagomine linked at N-1 via an acetic acid linker to a variable tripeptide was synthesised. The library was synthesised by Merrifield split and mix synthesis of the peptide, followed by capping with chloroacetate, regioselective nucleophilic substitution with 1-azafagomine and cleavage from the polymeric support. The library was screened for inhibition of beta-glucosidase, alpha-glucosidase and glycogen phosphorylase and found to display beta-glucosidase inhibition. Deconvolution of the library revealed that some inhibition was caused by all library members but the strongest inhibitor was clearly a compound having three hydroxyproline residues in the peptide fragment. This compound was a weaker but more selective inhibitor than 1-azafagomine itself.

Asunto(s)

Técnicas Químicas Combinatorias , Inhibidores Enzimáticos/síntesis química , Glicósido Hidrolasas/antagonistas & inhibidores , Secuencia de Carbohidratos , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Datos de Secuencia Molecular , Análisis Espectral

RESUMEN

Gadd45a-null mice generated by gene targeting exhibited several of the phenotypes characteristic of p53-deficient mice, including genomic instability, increased radiation carcinogenesis and a low frequency of exencephaly. Genomic instability was exemplified by aneuploidy, chromosome aberrations, gene amplification and centrosome amplification, and was accompanied by abnormalities in mitosis, cytokinesis and growth control. Unequal segregation of chromosomes due to multiple spindle poles during mitosis occurred in several Gadd45a -/- cell lineages and may contribute to the aneuploidy. Our results indicate that Gadd45a is one component of the p53 pathway that contributes to the maintenance of genomic stability.

Asunto(s)

Proteínas/genética , Animales , Apoptosis/genética , Ciclo Celular/genética , Ciclo Celular/fisiología , División Celular/genética , Transformación Celular Neoplásica/genética , Senescencia Celular , Centrosoma/metabolismo , Embrión de Mamíferos/citología , Femenino , Fibroblastos/citología , Fibroblastos/fisiología , Fase G1 , Rayos gamma/efectos adversos , Eliminación de Gen , Genes ras/genética , Péptidos y Proteínas de Señalización Intracelular , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Neoplasias/etiología , Neoplasias/genética , Fenotipo , Proteínas/fisiología , Hiperplasia del Timo/genética , Hiperplasia del Timo/patología , Proteinas GADD45

RESUMEN

1,4-Dideoxy-1,4-imino-d-arabinitol (DAB) was identified previously as a potent inhibitor of both the phosphorylated and non-phosphorylated forms of glycogen phosphorylase (EC 2.4.1.1). In the present study, the effects of DAB were investigated in primary cultured rat hepatocytes. The transport of DAB into hepatocytes was dependent on time and DAB concentration. The rate of DAB transport was 192 pmol/min per mg of protein per mM DAB(medium-concentration). In hepatocytes, DAB inhibited basal and glucagon-stimulated glycogenolysis with IC(50) values of 1.0+/-0.3 and 1.1+/-0.2 microM, respectively. The primary inhibitory effect of DAB on glycogenolysis was shown to be due to inhibition of glycogen phosphorylase but, at higher concentrations of DAB, inhibition of the debranching enzyme (4-alpha-glucanotransferase, EC 2.4.1.25) may have an effect. No effects on glycogen synthesis were observed, demonstrating that glycogen recycling does not occur in cultured hepatocytes under the conditions tested. Furthermore, DAB had no effects on phosphorylase kinase, the enzyme responsible for phosphorylation and thereby activation of glycogen phosphorylase, or on protein phosphatase 1, the enzyme responsible for inactivation of glycogen phosphorylase through dephosphorylation.

Asunto(s)

Glucógeno Hepático/metabolismo , Hígado/efectos de los fármacos , Alcoholes del Azúcar/farmacología , Animales , Arabinosa , Glucagón/farmacología , Iminofuranosas , Hígado/metabolismo , Masculino , Ratas , Ratas Wistar

RESUMEN

The present investigation was undertaken to characterize the direct inhibitory action of the peroxyvanadium compounds oxodiperoxo(1, 10-phenanthroline) vanadate(V) (bpV(phen)) and oxodiperoxo(pyridine-2-carboxylate) vanadate(V) (bpV(pic)) on pig microsomal glucose-6-phosphatase (G-6-Pase) activity and on glucagon stimulated hyperglycemia in vivo. Both bpV(phen) and bpV(pic) were found to be potent competitive inhibitors of G-6-Pase with Ki values of 0.96 and 0.42 microM (intact microsomes) and 0.50 and 0.21 microM (detergent-disrupted microsomes). The corresponding values for ortho-vanadate were 20.3 and 20.0 microM. Administration of bpV(phen) to postprandial rats did not affect the basal glucose level although a modest and dose-dependent increase in plasma lactate levels was seen. Injection of glucagon raised the plasma glucose level from 5.5 mM to about 7.5 mM in control animals and this increase could be prevented dose-dependently by bpV(phen). The inhibition of the glucagon-mediated blood glucose increase was accompanied by a dose-dependent increase in plasma lactate levels from 2 mM to about 11 mM. In conclusion, the finding that vanadate and bpV compounds are potent inhibitors of G-6-Pase suggests that the blood-glucose-lowering effect of these compounds which is seen in diabetic animals may be partly explained by a direct effect on this enzyme rather than, as presently thought, being the result of inhibition of phosphoprotein tyrosine phosphatases and thereby insulin receptor dephosphorylation.

Asunto(s)

Glucosa-6-Fosfatasa/antagonistas & inhibidores , Glucosa/metabolismo , Hígado/metabolismo , Compuestos Organometálicos/farmacología , Fenantrolinas/farmacología , Vanadatos/farmacología , Animales , Relación Dosis-Respuesta a Droga , Glucagón/farmacología , Insulina/farmacología , Hígado/efectos de los fármacos , Masculino , Microsomas Hepáticos/efectos de los fármacos , Imitación Molecular , Ratas , Ratas Sprague-Dawley

RESUMEN

Expression of a beta-lactoglobulin (BLG)/mdm2 transgene (BLGmdm2) in the epithelial cells of the mouse mammary gland causes an uncoupling of S phase from M phase, resulting in polyploidy and tumor formation. The cell cycle defects are independent of interactions with p53. Because MDM2 also binds and activates the S phase-specific transcription factor E2F1, we hypothesized that increased E2F1 activity causes the development of the BLGmdm2 phenotype. We, therefore, generated BLGmdm2 mice that were null for E2F1. We observed no notable differences in histology or cyclin gene expression between BLGmdm2 and BLGmdm2/E2F1-/- mice, indicating that endogenous E2F1 activity was not required for the BLGmdm2 phenotype. Because, depending on the experimental system, either loss of E2F1 function or overexpression of E2F1 results in transformation, we also tested whether overexpression of E2F1 augmented the severity of the BLGmdm2 phenotype by generating mice that were bitransgenic for BLGmdm2 and BLGE2F1. We observed a unique mixture of the two single transgenic phenotypes histologically and found no significant changes in cyclin levels, indicating that overexpression of E2F1 had no effect on the BLGmdm2 transgenic phenotype. Thus, increased expression or absence of E2F1 does not affect the ability of MDM2 to disrupt the cell cycle.

Asunto(s)

Proteínas Portadoras , Proteínas de Ciclo Celular , Proteínas de Unión al ADN , Proteínas Nucleares , Proteínas Proto-Oncogénicas/fisiología , Fase S/fisiología , Factores de Transcripción/fisiología , Animales , Mama/anatomía & histología , Bromodesoxiuridina/metabolismo , Ciclina A/metabolismo , Ciclina E/metabolismo , Factores de Transcripción E2F , Factor de Transcripción E2F1 , Células Epiteliales , Femenino , Genotipo , Histonas/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Modelos Biológicos , Fenotipo , Proteínas Proto-Oncogénicas c-mdm2 , Proteína 1 de Unión a Retinoblastoma , Factores de Tiempo , Factor de Transcripción DP1 , Proteína p53 Supresora de Tumor/metabolismo

RESUMEN

The neurotrophins brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) and their receptors trkB and trkC, respectively, are expressed in the locus coeruleus (LC) and ventral tegmental area (VTA), brain regions known to be involved in opiate addiction. Previously, administration of exogenous neurotrophins has been shown to oppose effects of chronic morphine treatment on LC and VTA neurons. However, the response of endogenous neurotrophins in LC and VTA to opiate treatment is unknown. In this study, BDNF, NT-3, trkB, and trkC mRNAs were analyzed in these regions after chronic morphine treatment and during antagonist precipitated withdrawal. Although chronic morphine exposure resulted in only modest increases in BDNF and NT-3 mRNA expression in LC, precipitated withdrawal led to a marked, rapid, and prolonged increase in BDNF mRNA and a delayed decrease in NT-3 mRNA. Levels of trkB and trkC mRNAs, which were unchanged by chronic morphine treatment, were elevated in LC at 2 and 6 hr of withdrawal. By 20 hr, trkB mRNA levels in LC had returned to control, whereas trkC mRNA levels fell below control values. In contrast to the substantial alterations observed in LC, there was no regulation of the neurotrophins or trk mRNAs within the VTA during chronic opiate treatment or withdrawal, with the exception of an increase in trkB mRNA at 6 hr of withdrawal. These results suggest that neurotrophins and their receptors per se may be involved in opiate-induced plasticity of the LC, whereas other mechanisms would appear to be involved in the VTA.

Asunto(s)

Factor Neurotrófico Derivado del Encéfalo/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Mesencéfalo/metabolismo , Morfina/farmacología , Factores de Crecimiento Nervioso/metabolismo , Proteínas Tirosina Quinasas Receptoras/metabolismo , Receptores de Factor de Crecimiento Nervioso/metabolismo , Animales , Factor Neurotrófico Derivado del Encéfalo/genética , Esquema de Medicación , Implantes de Medicamentos , Locus Coeruleus/efectos de los fármacos , Locus Coeruleus/metabolismo , Masculino , Mesencéfalo/efectos de los fármacos , Morfina/administración & dosificación , Factores de Crecimiento Nervioso/genética , Neurotrofina 3 , ARN Mensajero/biosíntesis , Ratas , Ratas Sprague-Dawley , Proteínas Tirosina Quinasas Receptoras/genética , Receptor de Factor Neurotrófico Ciliar , Receptor trkC , Receptores de Factor de Crecimiento Nervioso/genética , Factores de Tiempo , Área Tegmental Ventral/efectos de los fármacos , Área Tegmental Ventral/metabolismo

RESUMEN

Play assessment of children with prenatal cocaine exposure is discussed in terms of the developmental play level and behaviors manifest during spontaneous play and the clinical implications for assessing such children. Studies have found a number of subtle differences in the play skills of children with prenatal cocaine exposure compared to children with no cocaine exposure, however, sensitive outcome measures are needed to capture these subtle developmental differences. Suggestions for assessing play, an early developmental skill, using multidimensional play analyses that incorporate developmental play levels and associated play behaviors, such as initiation and perseveration are discussed.

Asunto(s)

Trastornos Relacionados con Cocaína/complicaciones , Juego e Implementos de Juego , Efectos Tardíos de la Exposición Prenatal , Conducta Exploratoria/fisiología , Femenino , Humanos , Lactante , Embarazo