RESUMEN
The spread of Plasmodium falciparum isolates carrying mutations in the kelch13 (Pfkelch13) gene associated with artemisinin resistance (PfART-R) in southeast Asia threatens malaria control and elimination efforts. Emergence of PfART-R in Africa would result in a major public health problem. In this systematic review, we investigate the frequency and spatial distribution of Pfkelch13 mutants in Africa, including mutants linked to PfART-R in southeast Asia. Seven databases were searched (PubMed, Embase, Scopus, African Journal Online, African Index Medicus, Bioline, and Web of Science) for relevant articles about polymorphisms of the Pfkelch13 gene in Africa before January, 2019. Following PRISMA guidelines, 53 studies that sequenced the Pfkelch13 gene of 23 100 sample isolates in 41 sub-Saharan African countries were included. The Pfkelch13 sequence was highly polymorphic (292 alleles, including 255 in the Pfkelch13-propeller domain) but with mutations occurring at very low relative frequencies. Non-synonymous mutations were found in only 626 isolates (2·7%) from west, central, and east Africa. According to WHO, nine different mutations linked to PfART-R in southeast Asia (Phe446Ile, Cys469Tyr, Met476Ile, Arg515Lys, Ser522Cys, Pro553Leu, Val568Gly, Pro574Leu, and Ala675Val) were detected, mainly in east Africa. Several other Pfkelch13 mutations, such as those structurally similar to southeast Asia PfART-R mutations, were also identified, but their relevance for drug resistance is still unknown. This systematic review shows that Africa, thought to not have established PfART-R, reported resistance-related mutants in the past 5 years. Surveillance using PfART-R molecular markers can provide valuable decision-making information to sustain the effectiveness of artemisinin in Africa.
Asunto(s)
Artemisininas/farmacología , Resistencia a Medicamentos/genética , Malaria Falciparum/tratamiento farmacológico , Plasmodium falciparum/genética , Proteínas Protozoarias/genética , África/epidemiología , Antimaláricos/farmacología , Antimaláricos/uso terapéutico , Artemisininas/uso terapéutico , ADN Protozoario/genética , ADN Protozoario/aislamiento & purificación , Genes Protozoarios/genética , Humanos , Malaria Falciparum/epidemiología , Malaria Falciparum/parasitología , Mutación , Plasmodium falciparum/efectos de los fármacos , Plasmodium falciparum/aislamiento & purificación , Polimorfismo de Nucleótido SimpleRESUMEN
BACKGROUND: Selpercatinib (LOXO-292) and pralsetinib (BLU-667) are highly potent RET-selective protein tyrosine kinase inhibitors (TKIs) for treating advanced RET-altered thyroid cancers and non-small-cell lung cancer (NSCLC). It is critical to analyze RET mutants resistant to these drugs and unravel the molecular basis to improve patient outcomes. PATIENTS AND METHODS: Cell-free DNAs (cfDNAs) were analyzed in a RET-mutant medullary thyroid cancer (MTC) patient and a CCDC6-RET fusion NSCLC patient who had dramatic response to selpercatinib and later developed resistance. Selpercatinib-resistant RET mutants were identified and cross-profiled with pralsetinib in cell cultures. Crystal structures of RET-selpercatinib and RET-pralsetinib complexes were determined based on high-resolution diffraction data collected with synchrotron radiation. RESULTS: RETG810C/S mutations at the solvent front and RETY806C/N mutation at the hinge region were found in cfDNAs of an MTC patient with RETM918T/V804M/L, who initially responded to selpercatinib and developed resistance. RETG810C mutant was detected in cfDNAs of a CCDC6-RET-fusion NSCLC patient who developed acquired resistance to selpercatinib. Five RET kinase domain mutations at three non-gatekeeper residues were identified from 39 selpercatinib-resistant cell lines. All five selpercatinib-resistant RET mutants were cross-resistant to pralsetinib. X-ray crystal structures of the RET-selpercatinib and RET-pralsetinib complexes reveal that, unlike other TKIs, these two RET TKIs anchor one end in the front cleft and wrap around the gate wall to access the back cleft. CONCLUSIONS: RET mutations at the solvent front and the hinge are resistant to both drugs. Selpercatinib and pralsetinib use an unconventional mode to bind RET that avoids the interference from gatekeeper mutations but is vulnerable to non-gatekeeper mutations.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Neoplasias de la Tiroides , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/genética , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/genética , Mutación , Inhibidores de Proteínas Quinasas , Proteínas Proto-Oncogénicas c-ret/genética , Pirazoles , Piridinas , Pirimidinas , Neoplasias de la Tiroides/tratamiento farmacológico , Neoplasias de la Tiroides/genéticaAsunto(s)
Anticuerpos Monoclonales Humanizados/administración & dosificación , Anticuerpos Monoclonales/administración & dosificación , Enfermedad Injerto contra Huésped/terapia , Trasplante de Células Madre Hematopoyéticas , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Esteroides/administración & dosificación , Aloinjertos , Femenino , Enfermedad Injerto contra Huésped/patología , Enfermedad de Hodgkin , Humanos , NivolumabRESUMEN
Severe aplastic anemia (SAA) is a rare disorder leading to bone marrow failure, which if left untreated, is invariably fatal. Conventional therapies with immunosuppressive therapy or allogeneic hematopoietic stem cell transplantation (HSCT) are highly effective. HSCT can offer a greater outcome in younger patients who have an available HLA match-related donor. Recent studies showing the addition of antithymocyte globulin (ATG) to the conditioning regimen improves engraftment and reduces the risk of graft-versus-host disease (GVHD).There are currently two ATG preparations in the USA, equine (or horse) and rabbit ATG. These agents are pharmacologically distinct, having significant differences in their pharmacokinetics and in vivo immunosuppressive effects [N Engl J Med 365(5):430-438, 2011]. Here, we report a case of two monozygotic twins with constitutional SAA that evolved to myelodysplastic syndrome (MDS) who both underwent allogeneic peripheral blood stem cell transplantation (PBSC) from the same single HLA antigen mismatched sibling donor with the only difference in the transplant regimen being the type of ATG used in the preparative regimen; one twin received horse ATG and the other received rabbit ATG during conditioning. This report emphasizes that dramatic differences in donor T cell chimerism and clinical outcomes including GVHD can occur as a consequence of the type of ATG that is utilized in the transplant conditioning regimen. These differences highlight that these agents should not be considered interchangeable drugs when used in this setting.
Asunto(s)
Anemia Aplásica/tratamiento farmacológico , Trasplante de Médula Ósea/métodos , Acondicionamiento Pretrasplante/métodos , Trasplante Homólogo/métodos , Animales , Niño , Progresión de la Enfermedad , Femenino , Caballos , Humanos , Conejos , Hermanos , Resultado del Tratamiento , Gemelos MonocigóticosRESUMEN
Rotavirus NSP1 has been shown to function as an E3 ubiquitin ligase that mediates proteasome-dependent degradation of interferon (IFN) regulatory factors (IRF), including IRF3, -5, and -7, and suppresses the cellular type I IFN response. However, the effect of rotavirus NSP1 on viral replication is not well defined. Prior studies used genetic analysis of selected reassortants to link NSP1 with host range restriction in the mouse, suggesting that homologous and heterologous rotaviruses might use their different abilities to antagonize the IFN response as the basis of their host tropisms. Using a mouse embryonic fibroblast (MEF) model, we demonstrate that heterologous bovine (UK and NCDV) and porcine (OSU) rotaviruses fail to effectively degrade cellular IRF3, resulting in IRF3 activation and beta IFN (IFN-beta) secretion. As a consequence of this failure, replication of these viruses is severely restricted in IFN-competent wild-type, but not in IFN-deficient (IFN-alpha/beta/gamma receptor- or STAT1-deficient) MEFs. On the other hand, homologous murine rotaviruses (ETD or EHP) or the heterologous simian rotavirus (rhesus rotavirus [RRV]) efficiently degrade cellular IRF3, diminish IRF3 activation and IFN-beta secretion and are not replication restricted in wild-type MEFs. Genetic reassortant analysis between UK and RRV maps the distinctive phenotypes of IFN antagonism and growth restriction in wild-type MEFs to NSP1. Therefore, there is a direct relationship between the replication efficiencies of different rotavirus strains in MEFs and strain-related variations in NSP1-mediated antagonism of the type I IFN response.
Asunto(s)
Fibroblastos/metabolismo , Interferón beta/metabolismo , Infecciones por Rotavirus/metabolismo , Rotavirus/fisiología , Proteínas no Estructurales Virales/metabolismo , Animales , Células Cultivadas , Embrión de Mamíferos/citología , Fibroblastos/virología , Humanos , Factor 3 Regulador del Interferón/genética , Factor 3 Regulador del Interferón/metabolismo , Interferón beta/genética , Ratones , Ratones Noqueados , Rotavirus/genética , Infecciones por Rotavirus/genética , Infecciones por Rotavirus/virología , Proteínas no Estructurales Virales/genética , Replicación ViralRESUMEN
Recent studies demonstrated that viremia and extraintestinal rotavirus infection are common in acutely infected humans and animals, while systemic diseases appear to be rare. Intraperitoneal infection of newborn mice with rhesus rotavirus (RRV) results in biliary atresia (BA), and this condition is influenced by the host interferon response. We studied orally inoculated 5-day-old suckling mice that were deficient in interferon (IFN) signaling to evaluate the role of interferon on the outcome of local and systemic infection after enteric inoculation. We found that systemic replication of RRV, but not murine rotavirus strain EC, was greatly enhanced in IFN-alpha/beta and IFN-gamma receptor double-knockout (KO) or STAT1 KO mice but not in mice deficient in B- or T-cell immunity. The enhanced replication of RRV was associated with a lethal hepatitis, pancreatitis, and BA, while no systemic disease was observed in strain EC-infected interferon-deficient mice. In IFN-alpha/beta receptor KO mice the extraintestinal infection and systemic disease were only moderately increased, while RRV infection was not augmented and systemic disease was not present in IFN-gamma receptor KO mice. The increase of systemic infection in IFN-deficient mice was also observed during simian strain SA11 infection but not following bovine NCDV, porcine OSU, or murine strain EW infection. Our data indicate that the requirements for the interferon system to inhibit intestinal and extraintestinal viral replication in suckling mice vary among different heterologous and homologous rotavirus strains, and this variation is associated with lethal systemic disease.
Asunto(s)
Interferones/inmunología , Infecciones por Rotavirus/inmunología , Infecciones por Rotavirus/patología , Rotavirus/inmunología , Animales , Linfocitos B/inmunología , Atresia Biliar/inmunología , Atresia Biliar/patología , Atresia Biliar/virología , Diarrea/inmunología , Diarrea/patología , Diarrea/virología , Hepatitis/inmunología , Hepatitis/patología , Hepatitis/virología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Pancreatitis/inmunología , Pancreatitis/patología , Pancreatitis/virología , Receptor de Interferón alfa y beta/deficiencia , Receptores de Interferón/deficiencia , Rotavirus/crecimiento & desarrollo , Factor de Transcripción STAT1/deficiencia , Análisis de Supervivencia , Linfocitos T/inmunología , Replicación Viral/inmunología , Receptor de Interferón gammaRESUMEN
Endothelial dysfunction is a characteristic of, and may be pathogenic in, inflammatory cardiovascular diseases, including sepsis. The mechanism underlying inflammation-induced endothelial dysfunction may be related to the expression and activity of inducible nitric oxide synthase (iNOS). This possibility was investigated in isolated resistance (mesenteric) and conduit (aorta) arteries taken from lipopolysaccharide (LPS)-treated (12.5 mg/kg i.v.) or saline-treated iNOS knockout (KO) and wild-type (WT) mice. LPS pretreatment (for 15 h, but not 4 h) profoundly suppressed responses to acetylcholine (ACh) and significantly reduced sensitivity to the NO donor spermine-NONOate (SPER-NO) in aorta and mesenteric arteries of WT mice. This effect was temporally associated with iNOS protein expression in both conduit and resistance arteries and with a 10-fold increase in plasma NOx levels. In contrast, no elevation of plasma NOx was observed in LPS-treated iNOS KO animals, and arteries dissected from these animals did not express iNOS or display hyporeactivity to ACh or SPER-NO. The mechanism underlying this phenomenon may be suppression of eNOS expression, as observed in arteries of WT animals, that was absent in arteries of iNOS KO animals. These results clearly demonstrate that iNOS induction plays an integral role in mediation of the endothelial dysfunction associated with sepsis in both resistance and conduit arteries.
Asunto(s)
Arterias/efectos de los fármacos , Endotelio Vascular/efectos de los fármacos , Lipopolisacáridos/farmacología , Óxido Nítrico Sintasa/genética , Espermina/análogos & derivados , Ácido 15-Hidroxi-11 alfa,9 alfa-(epoximetano)prosta-5,13-dienoico/farmacología , Acetilcolina/farmacología , Animales , Arterias/metabolismo , Arterias/fisiopatología , Relación Dosis-Respuesta a Droga , Endotelio Vascular/fisiopatología , Genotipo , Técnicas In Vitro , Ratones , Ratones Noqueados , Nitratos/sangre , Óxido Nítrico/metabolismo , Donantes de Óxido Nítrico/farmacología , Óxido Nítrico Sintasa/metabolismo , Óxido Nítrico Sintasa de Tipo II , Óxido Nítrico Sintasa de Tipo III , Nitritos/sangre , Óxidos de Nitrógeno , Norepinefrina/farmacología , Espermina/farmacología , Vasoconstricción/efectos de los fármacos , Vasoconstrictores/farmacología , Vasodilatadores/farmacologíaRESUMEN
AIM: The present study investigated the role of nerve growth factor (NGF) in the regeneration of noradrenergic nerves of right atria (following 6-hydroxydopamine; 6-OHDA, 100 mg/kg, i.p.) from non-diabetic and 8-week diabetic rats. RESULTS: In cryostat sections of the right atria, GAP-43 immunoreactivity was concentrated in nerve terminals, preterminal axons of the endocardium, epicardium and myocardium, as well as in nerve fibres innervating the blood vessels and ganglionic cells. In serial sections, all positive staining for GAP-43 showed immunoreactivity for the neuronal marker PGP-9.5. In untreated non-diabetic rats, the total GAP-43 immunoreactivity was reduced to 60% relative to pretreatment levels, at day 14 after 6-OHDA, as quantified by Western blotting. In diabetic rats, 6-OHDA treatment produced a marked increase in the levels of total GAP-43 at days 28 and 49. NGF treatment (1 mg/kg, s.c., 3 times/week, for 2 weeks) had no effect on the level of total GAP-43 in right atria from non-diabetic and diabetic rats before treatment with 6-OHDA. However, it normalized the reduced GAP-43 immunoreactivity observed in 6-OHDA-treated non-diabetic rats. Interestingly, NGF treatment alone produced an increase in GAP-43 phosphorylation relative to total GAP-43 in right atria from both non-diabetic (44%) and diabetic groups (42%). CONCLUSIONS: These findings suggest that nerve terminals of the right atria retain, in the mature adult, the capacity for structural and functional plasticity. The expression of GAP-43 in right atria of control and diabetic rats was differentially affected by 6-OHDA treatment. In injured noradrenergic neurones of the right atria, NGF modified the expression of GAP-43 only in non-diabetic rats and not in diabetic rats.
Asunto(s)
Diabetes Mellitus Experimental/metabolismo , Proteína GAP-43/biosíntesis , Factores de Crecimiento Nervioso/farmacología , Simpatectomía Química , Administración Oral , Animales , Proteína GAP-43/inmunología , Proteína GAP-43/metabolismo , Atrios Cardíacos/química , Atrios Cardíacos/efectos de los fármacos , Atrios Cardíacos/metabolismo , Inmunohistoquímica , Masculino , Factores de Crecimiento Nervioso/administración & dosificación , Oxidopamina/administración & dosificación , Oxidopamina/farmacología , Ratas , Ratas Wistar , Simpatectomía Química/métodos , Simpaticolíticos/administración & dosificación , Simpaticolíticos/farmacologíaRESUMEN
BACKGROUND: Although breast cancer is the second most common cancer among Vietnamese-American women, previous research has shown that they are less likely to have ever had, and to be more often overdue for, clinical breast examinations (CBE) and mammograms than women in the general population. METHODS: Over a 2.5-year period, the following intervention activities were targeted at both Vietnamese women and physicians in Alameda County, California: neighborhood-based educational activities; dissemination of health education materials; a media campaign; and continuing medical education seminars for physicians. Women in Los Angeles and Orange Counties served as controls. Preintervention telephone interviews were conducted with 384 randomly selected Vietnamese women in the intervention community and 404 women in the control community in 1996, and post-test intervention interviews were conducted with 405 and 402 women, respectively, in 1998. RESULTS: Multiple logistic regression analyses of postintervention surveys showed the intervention community women at posttest were no more likely to recognize, receive, plan, or be up-to-date for CBE or mammograms than women in the control community. However, women who reported greater exposure to the various intervention elements were significantly more likely to have heard of, have had, and to plan CBE and mammograms than women with less exposure. CONCLUSIONS: Although the effect on the women in the intervention group was not significant, the intervention did have a modest positive impact on women who had more exposure to it.
Asunto(s)
Asiático , Neoplasias de la Mama/diagnóstico por imagen , Mamografía , Tamizaje Masivo , Educación del Paciente como Asunto , Adulto , Neoplasias de la Mama/diagnóstico , Neoplasias de la Mama/psicología , Barreras de Comunicación , Servicios de Salud Comunitaria/estadística & datos numéricos , Femenino , Promoción de la Salud , Humanos , Medios de Comunicación de Masas , Persona de Mediana Edad , Relaciones Médico-Paciente , Vietnam/etnologíaRESUMEN
Alterations in multiple neurochemical systems have been reported in animal and human studies of posthypoxic myoclonus. It is impossible, however, to establish causative relationships between the observed changes and the myoclonic movements from these studies. Therefore, to establish causative links between neurochemical changes and myoclonus, ligands that target neurotransmitter systems that are altered in posthypoxic myoclonus were microinjected into the lateral ventricles of normal rats to identify the changes that can produce myoclonus. Of the ligands that were tested, only the GABA(A) antagonists produced myoclonus after intracerebroventricular administration, suggesting the importance of disinhibition of GABAergic systems in myoclonus. To further examine the role of GABA in myoclonus, GABAergic antagonists were microinjected into the nucleus reticularis of the thalamus (NRT), an area of the brain in which extensive pathologic changes are seen in posthypoxic animals. GABA(A), but not GABA(B), antagonists produced myoclonus after microinjection into the NRT. Earlier investigators have further reported the ability of GABA(A) antagonists to produce myoclonus after microinjection into the caudate. The data therefore suggest that disruption of activity at GABA(A) receptors at any one of a number of levels in the neural axis can produce myoclonus.
Asunto(s)
Epilepsias Mioclónicas/fisiopatología , Hipoxia Encefálica/fisiopatología , Mioclonía/fisiopatología , Receptores de GABA-A/fisiología , Animales , Mapeo Encefálico , Núcleo Caudado/fisiopatología , Corteza Cerebral/fisiopatología , Humanos , Núcleos Talámicos Intralaminares/fisiopatología , RatasRESUMEN
The study investigated the role of nerve growth factor (NGF) in the regeneration of noradrenergic nerves of the right atria from control and 8-week diabetic rats, after lesion caused by a single injection of 6-hydroxydopamine (6-OHDA, 100 mg/kg ip). This treatment caused a profound depletion of tissue noradrenaline (NA) of the right atria from both control and diabetic groups, followed by a progressive repletion that was not complete at 49 days. Immunoreactivity for the NGF receptors trkA and p75(NTR) was decreased and increased, respectively, between days 3 and 28 in right atria from diabetic rats and returned to pretreatment levels at day 49. Receptor levels were not significantly altered in controls. In contrast to tissue NA, at day 14 functional responses to electrical nerve stimulation of the right atria had completely returned to the pretreatment state in diabetic rats and were very close to normal in nondiabetic rats. NGF treatment (1 mg/kg, three times/week, for 2 weeks) increased tissue NA only in control rats; the pattern was similar after 6-OHDA. These findings are consistent with the hypothesis that NGF normally plays a role in the regulation of autonomic sympathetic nerves in the adult rat atrium and that mature and uninjured sympathetic neurons remain responsive to NGF. In injured noradrenergic neurons, NGF promotes regeneration in nondiabetic rats. The ability of NGF to promote regeneration of noradrenergic nerves is lost in diabetes and this may relate to the loss of trkA receptor on prejunctional nerve terminals after denervation.
Asunto(s)
Diabetes Mellitus Experimental/fisiopatología , Factores de Crecimiento Nervioso/farmacología , Regeneración Nerviosa/fisiología , Norepinefrina/metabolismo , Nervios Periféricos/fisiopatología , Animales , Función del Atrio Derecho/fisiología , Diabetes Mellitus Experimental/metabolismo , Estimulación Eléctrica , Atrios Cardíacos , Masculino , Miocardio/metabolismo , Factores de Crecimiento Nervioso/metabolismo , Regeneración Nerviosa/efectos de los fármacos , Oxidopamina/farmacología , Nervios Periféricos/efectos de los fármacos , Ratas , Ratas Wistar , Simpatectomía QuímicaRESUMEN
The rate of HIV transmission via breast-feeding ranges from 14% to 26%, depending on the timing of maternal infection. In settings where infant mortality rates from infectious diseases and malnutrition are low and relatively safe alternatives to breast-feeding are available, HIV-infected mothers should be advised not to breast-feed. Where breast-feeding by HIV-infected mothers and bottle-feeding both present serious risks of mortality, changing the conditions in which families live so that safe feeding alternatives become available must be a top priority. At the same time, these mothers need information about the relative risks and benefits of breast-feeding, early weaning, wet-nursing, and formula feeding. This article reviews the available research data and discusses critical gaps in current knowledge.
Asunto(s)
Lactancia Materna/efectos adversos , Infecciones por VIH/transmisión , Alimentación con Biberón , Consejo Dirigido , Femenino , Infecciones por VIH/prevención & control , Humanos , Mortalidad Infantil , Recién Nacido , Embarazo , Complicaciones Infecciosas del Embarazo/prevención & control , Factores de Riesgo , Factores de Tiempo , DesteteRESUMEN
This study examined links between impaired nitric oxide production in the sciatic endoneurium, nerve blood flow, and polyol pathway flux, to test the hypothesis that reduced nerve blood flow might be compromised by competition for NADPH between aldose reductase and nitric oxide synthase. Sciatic nerves of streptozotocin-diabetic rats showed reduced laser Doppler flux (by 51% or 63%; both p<0.05)-indicative of reduced nerve blood flow-and reduced motor nerve conduction velocity (17% in two experiments; p<0.05). Acute interruption of nitric oxide production in the sciatic nerves of control rats, via endoneurial injection of N omega-nitro-D-arginine methyl ester (L-NAME), caused a local reduction (of 64%; p<0.001) in nerve Doppler flux. This was reversed by either L-arginine or sodium nitroprusside. The response to L-NAME was greatly reduced in diabetic rats (only 22% reduction; p<0.01), though both L-arginine and SNP caused marked increases in flux. Chronic inhibition of aldose reductase in diabetic rats (with either sorbinil or imirestat at a range of doses) had little effect on resting sciatic nerve Doppler flux, though both inhibitors normalized conduction velocity. Both aldose reductase inhibitors reduced sorbitol pathway intermediates in a dose-related manner. These findings do not support the proposition that aldose reductase inhibitors normalise conduction velocity by mechanisms dependent upon either normalization of endoneurial nitric oxide or nerve blood flow. Instead, a mechanism based upon more direct effects on axon or Schwann cell function is favoured.
Asunto(s)
Aldehído Reductasa/antagonistas & inhibidores , Diabetes Mellitus Experimental/fisiopatología , Óxido Nítrico/biosíntesis , Nervio Ciático/irrigación sanguínea , Animales , Arginina/farmacología , Inhibidores Enzimáticos/farmacología , Flujometría por Láser-Doppler , Masculino , Neuronas Motoras/fisiología , NG-Nitroarginina Metil Éster/farmacología , Conducción Nerviosa/efectos de los fármacos , Óxido Nítrico Sintasa/antagonistas & inhibidores , Nitroprusiato/farmacología , Ratas , Ratas WistarRESUMEN
To explore further the role of VP4 as the rotavirus cell attachment protein, VP7 monoreassortants derived from the sialic-acid-dependent simian strain RRV and from the sialic-acid-independent human strains D, DS-1 and ST-3 were tested for susceptibility of infectivity of neuraminidase-treated MA-104 cells. Infectivity of RRV x D VP7 and RRV x ST-3 VP7 monoreassortants decreased when sialic acid was removed from the cell surface. However, of three separate RRV x DS-1 VP7 monoreassortants tested, only one was sialic-acid-dependent. Sequence analysis showed that both sialic-acid-independent strains contained a single amino acid change, Lys to Arg, at position 187. In addition, sialic-acid-independent infectivity was seen in one of 14 RRV VP4 neutralization escape mutants tested, and this strain was found to have a Gly to Glu change at amino acid position 150. These results indicate that positions 150 and 187 of VP4 play an important role in early rotavirus-cell interactions.
Asunto(s)
Antígenos Virales , Proteínas de la Cápside , Cápside/genética , Ácido N-Acetilneuramínico/metabolismo , Mutación Puntual , Rotavirus/genética , Rotavirus/patogenicidad , Animales , Cápside/metabolismo , Línea Celular , Genes Virales , Humanos , Macaca mulatta , Neuraminidasa , Rotavirus/metabolismo , Virulencia/genéticaRESUMEN
Sciatic endoneurial blood flow is reduced in experimental diabetes. This study examined the possible involvement of noradrenergic mechanisms in this impairment. In anaesthetised rats (pentobarbitone sodium 50 mg/kg, diazepam 2 mg/kg), sciatic nerve laser Doppler flux and vascular resistance in diabetic rats (5-6 weeks) were lower (approximately 50%) and higher (approximately 42%), respectively, than that in age-matched control rats, indicating nerve ischaemia in the diabetic tissues. Tyramine (1 nmol), noradrenaline (0.001-1 nmol) and phenylephrine (0.01-10 nmol) produced significant increases of nerve vascular resistance in control rats. The responses to tyramine (1 nmol) were completely blocked by desipramine (10 nmol) and those to phenylephrine (10 nmol) were reversed by phentolamine (1 nmol). In streptozotocin-diabetic rats, responses to phenylephrine or noradrenaline were enhanced compared to control rats, but the enhancement failed to reach statistical significance. The findings demonstrate that adrenergic stimulation affects sciatic nerve endoneurial blood flow.
Asunto(s)
Agonistas alfa-Adrenérgicos/farmacología , Diabetes Mellitus Experimental/fisiopatología , Nervio Ciático/irrigación sanguínea , Animales , Presión Sanguínea/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Flujometría por Láser-Doppler , Masculino , Norepinefrina/farmacología , Fenilefrina/farmacología , Ratas , Ratas Wistar , Nervio Ciático/efectos de los fármacos , Tiramina/farmacología , Resistencia Vascular/efectos de los fármacosRESUMEN
A Jennerian approach using live animal viruses to immunize humans is the current lead strategy for developing rotavirus vaccines. This strategy has been modified by incorporating human rotavirus VP7 genes into vaccine strains to induce serotype-specific neutralizing antibodies to human strains. However, the role of homotypic versus heterotypic immunity in protection is unclear. To investigate the importance of serotype-specific immunity in a mouse model, mice were immunized with rhesus rotavirus (RRV: G3, P5[3]), RRV-based modified Jennerian vaccine strains DxRRV (G1, P5[3]), DS1xRRV (G2, P5[3]), or ST3xRRV (G4, P5[3]), or bovine rotavirus NCDV (G6, P6[1]) and challenged with murine rotavirus ECw (G3, P[16]). Mice immunized with modified Jennerian vaccines exhibited complete to near-complete protection from challenge. NCDV-immunized mice also showed partial protection. The protection was correlated with fecal IgA levels to VP6, not serum IgG responses. Modified Jennerian vaccines induce both heterotypic and homotypic immunity in mice.
Asunto(s)
Proteínas de la Cápside , Cápside/inmunología , Inmunización/métodos , Inmunoglobulina A/inmunología , Infecciones por Rotavirus/inmunología , Infecciones por Rotavirus/prevención & control , Rotavirus/inmunología , Vacunas Sintéticas/inmunología , Animales , Anticuerpos Antivirales/análisis , Anticuerpos Antivirales/inmunología , Antígenos Virales/análisis , Cápside/genética , Células Cultivadas , Chlorocebus aethiops , Heces/química , Femenino , Inmunoglobulina G/inmunología , Masculino , Ratones , Pruebas de Neutralización , Rotavirus/genética , Infecciones por Rotavirus/sangreRESUMEN
1. This study examined the potential role of impaired nitric oxide production and response in the development of endoneurial ischaemia in experimental diabetes. Rats were anaesthetized (Na pentobarbitone 45 mg kg-1, diazepam 2 mg kg-1) for measurement of sciatic nerve laser Doppler flux and systemic arterial pressure. Drugs were administered into the sciatic endoneurium via a microinjector attached to a glass micropipette. 2. In two separate studies comparing diabetic rats (streptozotocin-induced; 8-10 wk duration) with controls, nerve Doppler flux in diabetic rats (Study 1, 116.6 +/- 40.4 and Study 2, 90.1 +/- 34.7 (s.d.) in arbitrary units) was about half that measured in controls (219.6 +/- 52.4 and 212.8 +/- 95.5 respectively; P < 0.005 for both). There were no significant differences between the two in systemic arterial pressure. 3. Inhibition of nitric oxide production by microinjection of 1 nmol L-NAME into the endoneurium halved flux in controls (to 126.3 +/- 41.3 in Study 1 and 102.1 +/- 38.9 in Study 2; both P < 0.001), with no significant effect in diabetic rats, indicating markedly diminished tonic nitric oxide production in the latter. D-NAME was without effect on nerve Doppler flux. 4. L-Arginine (100 nmol), injected after L-NAME, markedly increased flux in controls (by 65.8% (P < 0.03) and 97.8% (P < 0.01) in the two studies) and by proportionally similar amounts in diabetic rats [75.8% (P < 0.001) and 60.2% (P < 0.02)]. The nitro-donor, sodium nitroprusside (SNP; 10 nmol) had similar effects to L-arginine in both groups (increases of 66.0% in controls and 77.5% in diabetics; both P < 0.002). 5. A second diabetic group, treated with evening primrose oil performed exactly like control rats in respect of responses to L-NAME, L-arginine and SNP. 6. These findings implicate deficient nitric oxide in nerve ischaemia of diabetes and suggest correction thereof as a mechanism of action of evening primrose oil.
Asunto(s)
Arginina/análogos & derivados , Arginina/farmacología , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/fisiopatología , Ácidos Grasos Esenciales/farmacología , Óxido Nítrico/fisiología , Nitroprusiato/farmacología , Nervio Ciático/irrigación sanguínea , Vasodilatadores/farmacología , Animales , Activación Enzimática , Inhibidores Enzimáticos/farmacología , Guanilato Ciclasa/metabolismo , Ácidos Linoleicos , NG-Nitroarginina Metil Éster , Óxido Nítrico/biosíntesis , Óxido Nítrico Sintasa/antagonistas & inhibidores , Oenothera biennis , Aceites de Plantas , Ratas , Ácido gammalinolénicoRESUMEN
The infectivity of rotavirus particles is dependent on proteolytic cleavage of the outer capsid protein, VP4, at a specific site. This cleavage event yields two fragments, identified as VP5* and VP8*. It has been hypothesized that the particle is more stable, but non-infectious, when VP4 is in the uncleaved state. Uncleaved VP4 and the resultant increased stability might be advantageous for the virus to resist environmental degradation until it infects a susceptible host. When VP4 is cleaved in the lumen of the host's gastrointestinal tract, the virus particle would become less stable but more infectious. To test this hypothesis, a series of experiments was undertaken to analyse the cleavage state of VP4 on virus shed by an infected host into the environment. Immunoblots of intestinal wash solutions derived from infant and adult BALB/c mice infected with a virulent cell culture-adapted variant of the EDIM virus (EW) or wild-type murine rotavirus EDIM-Cambridge were analysed. Virtually all of the VP4 in these samples was in the cleaved form. Moreover, cell culture titration of trypsin-treated and untreated intestinal contents from pups infected with EW indicated that excreted virus is fully activated prior to trypsin addition. It was also observed that trypsin-activated virus has no disadvantage in initiating infection in naive animals over virions containing an intact VP4. These studies indicate that VP4 is cleaved upon release from the intestinal cell and that virus shed into the environment does not have an intact VP4.
Asunto(s)
Cápside/metabolismo , Infecciones por Rotavirus/virología , Rotavirus/fisiología , Animales , Western Blotting , Proteínas de la Cápside , Diarrea/virología , Enfermedades Intestinales/virología , Ratones , Ratones Endogámicos BALB C , Rotavirus/metabolismo , Esparcimiento de VirusRESUMEN
Fourteen patients with chronic dorsal wrist pain of unknown etiology underwent high-resolution magnetic resonance imaging (MRI) examination formatted to evaluate the scapholunate interval. Ten had MRI evidence that was diagnostic for an occult dorsal wrist ganglion. The average measured 4.7 mm at greatest diameter. Eight of 10 patients had the diagnosis confirmed, 7 at the time of surgery, and 1 at follow-up examination when the ganglion enlarged and was no longer occult. The other two opted for nonoperative management. The positive predictive value of a positive MRI finding for occult dorsal wrist ganglion was 100% in this small series. The use of a properly formatted high-resolution MRI in this patient population was diagnostic for occult dorsal wrist ganglion.