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1.
Res Vet Sci ; 152: 289-299, 2022 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-36081252

RESUMEN

The reliability of four lactate threshold (LT) methods to estimate the maximal lactate steady state (MLSS), defined as the highest intensity that can be maintained without plasma lactate ([La-]) accumulation over time, was determined in Beagle dogs. Six male Beagle dogs performed a standardized incremental exercise test on a treadmill when plasma lactate ([La-]) measurements were performed. The LTs for predicting MLSS, were determined by visual inspection (LTV), using a bi-segmented linear regression model (LTBI), or using a polynomial function on the [La-]/velocity ratio (LTP) by considering the vertices of the curve and calculating the point that yields the maximal distance from a curve representing [La-] as a function of velocity to the line formed by the two endpoints of the curve (LTDMAX method). The agreement was assessed using Bland-Altman plots and ordinary least products (OLP) regression among the velocities corresponding to the LTs identified using different methods (VLTv, VLTBI, VLTP, and VLTDMAX) and the velocity corresponding to the MLSS (VMLSS). A principal component (PC) analysis approach was performed to detect the degree of co-relatedness among the variables. The mean ± SD [La-] at MLSS was 1.03 ± 0.24 mM. VMLSS had a lower mean bias with VLTv, followed by VLTBI. The VLTDMAX underestimated MLSS. VLTv and VLTBI had the lowest limits of agreement with the VMLSS. The VLTP and VLTDMAX showed relatively high limits of agreement with MLSS. VLTv, VLTBI, and VMLSS had more collinearity and were dominantly aligned with the second component (PC2). VLTv and VLTBI can be used as simple methods to objectively determine aerobic fitness in Beagle dogs.


Asunto(s)
Prueba de Esfuerzo , Ácido Láctico , Perros , Masculino , Animales , Prueba de Esfuerzo/veterinaria , Reproducibilidad de los Resultados , Modelos Lineales
2.
J Anim Sci ; 100(6)2022 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-35579995

RESUMEN

In pigs, the gut microbiota composition plays a major role in the process of digestion, but is influenced by many external factors, especially diet. To be used in breeding applications, genotype by diet interactions on microbiota composition have to be quantified, as well as their impact on genetic covariances with feed efficiency (FE) and digestive efficiency (DE) traits. This study aimed at determining the impact of an alternative diet on variance components of microbiota traits (genera and alpha diversity indices) and estimating genetic correlations between microbiota and efficiency traits for pigs fed a conventional (CO) or a high-fiber (HF) diet. Fecal microbes of 812 full-siblings fed a CO diet and 752 pigs fed the HF diet were characterized at 16 weeks of age by sequencing the V3-V4 region of the 16S rRNA gene. A total of 231 genera were identified. Digestibility coefficients of nitrogen, organic matter, and energy were predicted analyzing the same fecal samples with near infrared spectrometry. Daily feed intake, feed conversion ratio, residual feed intake and average daily gain (ADG) were also recorded. The 71 genera present in more than 20% of individuals were retained for genetic analyses. Heritability (h²) of microbiota traits were similar between diets (from null to 0.38 ±â€…0.12 in the CO diet and to 0.39 ±â€…0.12 in the HF diet). Only three out of the 24 genera and two alpha diversity indices with significant h² in both diets had genetic correlations across diets significantly different from 0.99 (P < 0.05), indicating limited genetic by diet interactions for these traits. When both diets were analyzed jointly, 59 genera had h² significantly different from zero. Based on the genetic correlations between these genera and ADG, FE, and DE traits, three groups of genera could be identified. A group of 29 genera had abundances favorably correlated with DE and FE traits, 14 genera were unfavorably correlated with DE traits, and the last group of 16 genera had abundances with correlations close to zero with production traits. However, genera abundances favorably correlated with DE and FE traits were unfavorably correlated with ADG, and vice versa. Alpha diversity indices had correlation patterns similar to the first group. In the end, genetic by diet interactions on gut microbiota composition of growing pigs were limited in this study. Based on this study, microbiota-based traits could be used as proxies to improve FE and DE in growing pigs.


The link between the composition of the gut microbiota, i.e the composition of microorganisms in the gut, in pigs and their feed efficiency, i.e. their ability to utilize nutrients, as well as their ability to digest were studied from a genetic point of view. A family structure of 1,564 pigs were studied and fed with two different diets. One of the full-sib was fed a conventional diet used in breeding farms and the other one an alternative diet containing raw materials, less expensive but with a higher content of dietary fibers more difficult to digest. This study has shown that some microbiota microorganisms were genetically correlated with feed and digestive efficiency performances, positively or negatively, depending on the microorganisms. In addition, the diversity of microorganisms in the animal's gut was favorably correlated with the feed and digestive performances studied. Therefore, there is a genetic link between these performances and the composition of the animal's gut microbiota. Thus, a potential genetic selection on some intestinal microorganisms or diversity of microorganisms would allow to improve these performances, and in particular when pigs are fed with diet more difficult to digest.


Asunto(s)
Microbioma Gastrointestinal , Alimentación Animal/análisis , Animales , Dieta/veterinaria , Heces , ARN Ribosómico 16S/genética , Porcinos/genética
3.
BMC Pediatr ; 22(1): 212, 2022 04 18.
Artículo en Inglés | MEDLINE | ID: mdl-35436899

RESUMEN

BACKGROUND: Risky media use in terms of accumulating too much time in front of screens and usage before bedtime in early childhood is linked to developmental delays, reduced sleep quality, and unhealthy media use in later childhood and adulthood. For this reason, we examine patterns of media use in pre-school children and the extent to which child and family characteristics contribute to media use during the COVID-19 pandemic. METHODS: A cross-sectional study of digital media use by Canadian preschool-aged children (mean age = 3.45, N = 316) was conducted at the start of the COVID-19 pandemic between April and August of 2020. Parents completed a questionnaire and 24-h recall diary in the context of an ongoing study of child digital media use. From these responses we estimated hours of average daily screen time, screen time in the past 24 h, average daily mobile device use, and media use before bedtime. Parents also answered questions about their child (i.e., age, sex, temperament), family characteristics (parental mediation style, parental screen time, education, income), and contextual features of the pandemic (ex., remote work, shared childcare). Daycare closures were directly assessed using a government website. RESULTS: Our results indicate that 64% of preschoolers used more than 2 h of digital media hours/day on average during the pandemic. A majority (56%) of children were also exposed to media within the hour before bedtime. Logistic and multinomial regressions revealed that child age and temperament, restrictive parental mediation, as well as parent digital media use, education, satisfaction with the division of childcare, remote work, and number of siblings and family income were all correlates of risky digital media use by preschoolers. CONCLUSIONS: Our results suggest widespread risky media use by preschoolers during the pandemic. Parenting practices that include using more restrictive mediation strategies may foster benefits in regulating young children's screen time.


Asunto(s)
COVID-19 , Pandemias , Adulto , COVID-19/epidemiología , COVID-19/prevención & control , Canadá/epidemiología , Niño , Preescolar , Estudios Transversales , Humanos , Internet , Responsabilidad Parental , Padres , Tiempo de Pantalla
4.
J Public Health (Oxf) ; 43(4): 867-875, 2021 12 10.
Artículo en Inglés | MEDLINE | ID: mdl-32888032

RESUMEN

BACKGROUND: The non-communicable diseases are the major causes of death both worldwide and in high-income countries such as Norway. Understanding whether policy programs affect the health of older adults, especially considering different realities, is crucial. We aimed to analyse cardiometabolic risk factors associated with educational level in elderly people from Norway and Brazil. METHODS: A total of 555 elderly people recruited from Trondheim, Norway (n = 310, age 70.7 ± 0.8 years, body mass index (BMI) 26.2 ± 3.9 kg/m2) and from Ribeirao Preto, Brazil (n = 245, age 64.1 ± 8.1 years, BMI 28.2 ± 5.5 kg/m2). All analyses were adjusted for age and sex, considering country as an independent variable. The significance level considered was P < 0.05. RESULTS: Brazilian people presented a higher incidence of overweight and higher waist circumference (WC) compared to Norwegian (28.2 ± 5.5 kg/m2 and 97.0 ± 14.7 cm versus 26.4 ± 3.9 kg/m2 and 92.1 ± 11.2 cm, respectively). When classified by education level, Brazilians presented higher values for BMI, WC and triglycerides (TG) than Norwegians with the same level of education (incomplete higher education), while Norwegians presented higher values for systolic blood pressure (SBP), cholesterol total (CT), high-density lipoprotein (HDL)-cholesterol, LDL-cholesterol and handgrip strength. CONCLUSIONS: Both nationalities presented important cardiometabolic risk factors. However, when considering a low level of education, the Brazilian elderly people presented more cardiometabolic risk factors than Norwegians.


Asunto(s)
Factores de Riesgo Cardiometabólico , Enfermedades Cardiovasculares , Anciano , Presión Sanguínea , Índice de Masa Corporal , Brasil/epidemiología , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/etiología , Estudios Transversales , Escolaridad , Fuerza de la Mano , Humanos , Persona de Mediana Edad , Noruega/epidemiología , Factores de Riesgo , Circunferencia de la Cintura
5.
Physica A ; 559: 125067, 2020 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-32834437

RESUMEN

The spreading of epidemics in complex networks has been a subject of renewed interest of several scientific branches. In this regard, we have focused our attention on the study of the susceptible-infected-susceptible (SIS) model, within a Monte Carlo numerical simulation approach, representing the spreading of epidemics in a clustered homophilic network. The competition between infection and recovery that drives the system either to an absorbing or to an active phase is analyzed. We estimate the static critical exponents ß ∕ ν , 1 ∕ ν and γ ∕ ν , through finite-size scaling (FSS) analysis of the order parameter ρ and its fluctuations, showing that they differ from those associated with the contact process on a scale-free network, as well as those predicted by the heterogeneous mean-field theory.

6.
Transl Med UniSa ; 23: 82-91, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34447721

RESUMEN

AIM: This study aimed to assess the effectiveness of the group Reminiscence Therapy (RT) on cognition, depressive symptoms, and quality of life (QOL) in older adults recruited in nursing homes. METHODS: A pilot study with a one-group pretest-posttest design was conducted between September 2017 and March 2018 in five nursing homes from central Portugal. A comprehensive RT program (Core program followed by a Follow-up program) was provided to clinically stable volunteers aged 65 years or more, who did not have severe cognitive impairment. RESULTS: From the 50 older adults (32 women and 18 men, with mean age of 83.32±7.76, and mean education level of 5.48±4.05) considered eligible to participate in the study, 35 (mean age: 84.17±7.46, mean education level of 6.14±4.49) completed the Core Program and 28 completed the Follow-up Program (mean age: 84.25±7.66, mean education level of 6.18±4.57). Based on the Wilcoxon Test, it was observed that the participants' cognitive performance did not change during the two RT programs. No significant changes were confirmed in relation to depressive symptomatology and QOL. CONCLUSION: Although no statistically significant improvements of the older adults' cognitive function, depressive symptomatology, and quality of life were found, the stabilization of such outcomes are relevant from a clinical viewpoint. Further studies are necessary to confirm these findings.

7.
JPRAS Open ; 16: 50-60, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32158810

RESUMEN

INTRODUCTION: Decubitus ulcers of the sacral region are common conditions in bedridden patients. Deep lesions (Stages III and IV) often require surgical treatment for closure. Flaps of the region are the first choice for treatment. We present our experience in the treatment of these lesions and compare two different approaches: local fasciocutaneous flap and gluteus maximus myocutaneous flap with V-Y advancement. METHOD: From March 2009 to May 2014, 32 patients underwent closure of sacral pressure ulcers by flaps, 17 of them with rotational local fasciocutaneous flaps and 15 with myocutaneous flaps of the gluteus maximus muscle with V-Y advancement. Evolution regarding complications and rate of success after two months was compared between the groups. RESULTS: Out of the 32 operated patients we obtained resolution of lesions after two months in 23 (71.8%), 10 patients in the fasciocutaneous flap group (58.8%) and 13 cases in the myocutaneous flap group (86.6%). The most common complication was partial dehiscence of sutures in 12 patients (37.5%), 8 patients in the fasciocutaneous flap group (47%) and 4 patients in the myocutaneous flap group (26.6%). The group of patients reconstructed with local fasciocutaneous flaps presented 3 cases with seroma, one with hematoma and 6 with partial cutaneous necrosis; these patients also required more drainage time. CONCLUSIONS: Both the local rotational fasciocutaneous flap and the myocutaneous flap of the gluteus maximus muscle in V-Y flap can be used in the surgical treatment of sacral ulcers. In our experience, a reduced success rate and more complications were found in the local fasciocutaneous reconstructive method.

8.
J Trop Pediatr ; 48(5): 300-2, 2002 10.
Artículo en Inglés | MEDLINE | ID: mdl-12405173

RESUMEN

To determine the efficacy of a reassortant rhesus-human tetravalent rotavirus vaccine (RRV-TV) (4 x 10(4) pfu/dose) against P and G rotavirus genotypes, 90 positive samples were tested using reverse transcription-polymerase chain reaction. The efficacy of the RRV-TV vaccine against P[8] and G1 individually or in binary combination P[8], G1 was 72 per cent (p < 0.005) 61 per cent (p < 0.013), and 70 per cent (p < 0.009), respectively, only for the first year of follow-up. In the second year, as well as after 2 years of follow-up, no efficacy was observed to these genotypes. These data indicate that further studies with rotavirus vaccines should focus on the molecular characterization of rotaviruses genotypes, in order to see whether or not cross-protection among different G and P genotypes may occur as a result of common bearing of VP4 specificities.


Asunto(s)
Infecciones por Rotavirus/prevención & control , Vacunas contra Rotavirus/uso terapéutico , Vacunas Atenuadas/uso terapéutico , Brasil/epidemiología , Genotipo , Humanos , Virus Reordenados , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Rotavirus/genética , Infecciones por Rotavirus/epidemiología
9.
Clin Genet ; 61(5): 380-3, 2002 May.
Artículo en Inglés | MEDLINE | ID: mdl-12081724

RESUMEN

Deletions of chromosome 22q11.2 are recognized as the main cause of a number of clinical phenotypes, including velocardiofacial syndrome (VCFS) and DiGeorge syndrome (DGS). Velocardiofacial syndrome is a relatively common developmental disorder that is characterized by craniofacial anomalies and conotruncal heart defects. Most 22q11.2 deletions occur sporadically, although the deletion may be transmitted in some cases. The present performed a molecular analysis in one family including a patient with clinical diagnosis of VCFS and his sister with a suggestive phenotype. Six polymorphic 22q11.2 markers (i.e. D22S420, D22S264, D22S941, D22S306, D22S425 and D22S257) were used for genotype analysis of the DNA from the patients and unaffected relatives. The results revealed a 22q11.2 deletion in the patient and his sister from one of six markers (i.e. D22S941). Genotype analysis demonstrated that the deletion in this sib was of maternal origin. The results suggest that the mother probably has gonadal mosaicism. The other relatives present normal DNA profiles for all markers. These results have implications for genetic counseling because of a risk of transmission by germ cells carrying the deletion, even when parents present with a normal DNA profile in their blood cells.


Asunto(s)
Deleción Cromosómica , Cromosomas Humanos Par 22 , Anomalías Craneofaciales/genética , Cardiopatías Congénitas/genética , Femenino , Genotipo , Células Germinativas , Humanos , Recién Nacido , Masculino , Mosaicismo
10.
Clin Dysmorphol ; 11(2): 129-32, 2002 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-12002144

RESUMEN

We report a Brazilian female patient with a thin and long face, blepharophimosis, minor auricular anomalies, camptodactyly and thoracic and spinal anomalies. The constellation of clinical signs present in this patient is consistent with the diagnosis of Guadalajara camptodactyly syndrome type I. Clinical and genetic aspects concerning this condition are discussed.


Asunto(s)
Anomalías Craneofaciales , Anomalías Múltiples/genética , Niño , Anomalías Craneofaciales/genética , Facies , Femenino , Retardo del Crecimiento Fetal/genética , Dedos/anomalías , Genes Recesivos , Humanos , Síndrome
11.
Gac Med Mex ; 137(3): 191-202, 2001.
Artículo en Español | MEDLINE | ID: mdl-11432088

RESUMEN

OBJECTIVE: To describe the trends and risk factors of death for bacteremia in adult from a tertiary-care center from 1981 to 1992. MATERIAL AND METHODS: We randomly included 20% of bacteremic episodes per year. RESULTS: 47,618 blood-cultures from 19,530 patients, 3428 patients (17.6%) had bacteremia (285/y). From 600 episodes (50/y), 307 were from men, 368 were hospital-acquired (HA), and 88% were monomicrobial. Diabetes mellitus was seen in 103 cases, cirrhosis of the liver in 98, and AIDS in 33, among others. The main microorganisms were: Escherichia coli (177), Klebsiella pneumoniae (53), Enterobacter (50), Salmonella (45) and Pseudomonas aeruginosa (35); coagulase-negative staphylococci (CNS) (116), Staphylococcus aureus (56), and enterococci (22), and Candida (20). CNS decreased during the study (p < 0.01), but Candida spp., Stenotrophomonas maltophilia and enterococci increased (p < 0.01). The crude mortality of the HA bacteremia was 70.8%, and 29.2% in the case of community-acquired, the mortality attributable to HA bacteremia was 41.6%. The main risk factors were: cardiac valvular disease (p < 0.001), stay at the intensive-care unit (p < 0.001), sepsis (p < 0.001), and pneumonia (p < 0.001). DISCUSSION: Bacteremia had a significant impact on mortality during the study period that has not change despite opportune therapy, Enterococci and candida have emerged as significant pathogens.


Asunto(s)
Bacteriemia/epidemiología , Adulto , Anciano , Anciano de 80 o más Años , Bacteriemia/microbiología , Bacteriemia/mortalidad , Candidiasis/epidemiología , Comorbilidad , Infección Hospitalaria/epidemiología , Infección Hospitalaria/microbiología , Infecciones por Enterobacteriaceae/epidemiología , Femenino , Fungemia/epidemiología , Fungemia/microbiología , Fungemia/mortalidad , Hospitales Públicos/estadística & datos numéricos , Humanos , Incidencia , Tablas de Vida , Masculino , México/epidemiología , Persona de Mediana Edad , Morbilidad/tendencias , Factores de Riesgo , Infecciones Estafilocócicas/epidemiología , Análisis de Supervivencia , Salud Urbana/estadística & datos numéricos
12.
FEMS Microbiol Lett ; 201(1): 65-72, 2001 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-11445169

RESUMEN

Trypanosomatids are widespread in several plant families and although most isolates have been classified as Phytomonas, other trypanosomatid genera can also infect plants. In order to assess the natural occurrence of non-Phytomonas trypanosomatids in plants we characterized 21 new trypanosomatid cultures, 18 from fruits and three from seeds of 17 plant species. The trypanosomatids from fruit and seeds were compared in terms of morphological, growth, biochemical and molecular features. The high diversity among the isolates permitted the classification of the new flagellates into the genera Crithidia and Leptomonas as well as Phytomonas. The data showed that natural fruit infection with non-Phytomonas trypanosomatids is more common than usually thought, being detected in 43% of the fruit isolates.


Asunto(s)
Frutas/parasitología , Semillas/parasitología , Trypanosomatina/clasificación , Animales , Crithidia/clasificación , Crithidia/citología , Crithidia/aislamiento & purificación , Crithidia/fisiología , Dermatoglifia del ADN , Técnica del Anticuerpo Fluorescente Indirecta , Hibridación de Ácido Nucleico , Reacción en Cadena de la Polimerasa , Técnica del ADN Polimorfo Amplificado Aleatorio , Ribotipificación , Trypanosomatina/citología , Trypanosomatina/aislamiento & purificación , Trypanosomatina/fisiología
13.
Clin Dysmorphol ; 10(2): 81-6, 2001 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11311001

RESUMEN

We report a Brazilian boy, born to normal and nonconsanguineous parents showing, among other signs, brachycephaly, a wide forehead, a widow's peak, hypertelorism, wide palpebral fissures with multiple eyelid colobomas, a broad nasal root, a long philtrum, macrostomia, prominent lips, a high arched palate, a midline alveolar cleft, a small and grooved chin, ear anomalies, structural anomaly of the corpus callosum, and mental retardation. To our knowledge this additional patient defines a particular clinical condition previously reported [Guion-Almeida M.L. Richieri-Costa A. (1999) Clinical Dysmorphol 8;1-4; Masuno M. et al. (2000) Clin Dysmorphol 9:59-60].


Asunto(s)
Anomalías Múltiples/diagnóstico , Coloboma/diagnóstico , Oído/anomalías , Párpados/anomalías , Discapacidad Intelectual/diagnóstico , Macrostomía/diagnóstico , Anomalías Múltiples/genética , Agenesia del Cuerpo Calloso , Niño , Coloboma/genética , Diagnóstico Diferencial , Salud de la Familia , Humanos , Discapacidad Intelectual/genética , Macrostomía/genética , Masculino , Nariz/anomalías , Fenotipo
14.
Clin Dysmorphol ; 9(4): 253-7, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11045580

RESUMEN

Cerebro-oculo-nasal syndrome is a rare multiple congenital anomaly syndrome with structural anomalies of the central nervous system, anophthalmia, and abnormal nares. In this report two additional cases are presented, one of them without central nervous system and/or ocular anomalies.


Asunto(s)
Anomalías Múltiples/patología , Encéfalo/anomalías , Anomalías del Ojo/patología , Nariz/anomalías , Encéfalo/diagnóstico por imagen , Femenino , Humanos , Recién Nacido , Masculino , Síndrome , Tomografía Computarizada por Rayos X
15.
Clin Dysmorphol ; 9(4): 269-72, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11045583

RESUMEN

We report on a male patient with a constellation of malformations, including cleft lip/palate, abnormal ears, ectrodactyly, congenital heart defect (CHD), and growth retardation. A similar association has been previously reported twice [Richieri-Costa and Orquizas (1987) Rev Brasil Genet X:787-792; Giannotti et al. (1995) J Med Genet 32:72-74], and autosomal recessive inheritance was proposed.


Asunto(s)
Anomalías Múltiples/patología , Encéfalo/anomalías , Encéfalo/diagnóstico por imagen , Labio Leporino/patología , Fisura del Paladar/patología , Discapacidades del Desarrollo/patología , Oído/anomalías , Cara/anomalías , Cardiopatías Congénitas/patología , Humanos , Recién Nacido , Masculino , Sindactilia/patología , Síndrome , Tomografía Computarizada por Rayos X
16.
Clin Dysmorphol ; 9(4): 297-9, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11045592

RESUMEN

We report a Brazilian boy, born to consanguineous parents. On the left arm there was a proximal 'ring shaped' constriction, regional aplasia cutis, and a short hand with markedly hypoplastic fingers and nails 2-3. He also had a bilateral cleft lip/palate, preaxial polydactyly involving the distal phalanx of the left index finger, and a supernumerary nipple on the right. The differential diagnosis is discussed.


Asunto(s)
Anomalías Múltiples/patología , Síndrome de Bandas Amnióticas/patología , Cara/anomalías , Genes Recesivos , Microcefalia/patología , Polidactilia/patología , Anomalías Múltiples/diagnóstico por imagen , Anomalías Múltiples/genética , Humanos , Recién Nacido , Masculino , Radiografía
17.
J Biol Chem ; 275(16): 12147-55, 2000 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-10766850

RESUMEN

The glycosylphosphatidylinositol-specific phospholipase C or VSG lipase is the enzyme responsible for the cleavage of the glycosylphosphatidylinositol anchor of the variant surface glycoprotein (VSG) and concomitant release of the surface coat in Trypanosoma brucei during osmotic shock or extracellular acidic stress. In Xenopus laevis oocytes the VSG lipase was expressed as a nonacylated and a thioacylated form. This thioacylation occurred within a cluster of three cysteine residues but was not essential for catalytic activity per se. These two forms were also detected in trypanosomes and appeared to be present at roughly equivalent amounts. A reversible shift to the acylated form occurred when cells were triggered to release the VSG by either nonlytic acid stress or osmotic lysis. A wild type VSG lipase or a gene mutated in the three codons for the acylated cysteines were reinserted in the genome of a trypanosome null mutant for this gene. A comparative analysis of these revertant trypanosomes indicated that thioacylation might be involved in regulating enzyme access to the VSG substrate.


Asunto(s)
Cisteína/metabolismo , Trypanosoma brucei brucei/enzimología , Fosfolipasas de Tipo C/metabolismo , Acilación , Animales , Animales Modificados Genéticamente , Electroforesis en Gel de Poliacrilamida , Glicosilfosfatidilinositol Diacilglicerol-Liasa , Mutagénesis Sitio-Dirigida , Ácido Mirístico/metabolismo , Oocitos/metabolismo , Plásmidos , ARN Mensajero/metabolismo , Relación Estructura-Actividad , Compuestos de Sulfhidrilo/metabolismo , Transfección , Trypanosoma brucei brucei/genética , Fosfolipasas de Tipo C/genética , Xenopus laevis
18.
J Cell Sci ; 112 ( Pt 23): 4461-73, 1999 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-10564663

RESUMEN

African trypanosomes are coated by 10 million copies of a single variant specific glycoprotein (VSG) which are anchored in the plasma membrane by glycosylphosphatidylinositol (GPI). A GPI-specific phospholipase C (GPI-PLC) triggers fast VSG release upon cell lysis but in vivo it is safely controlled and topologically concealed from its substrate by being intracellular. One enigmatic aspect of GPI-PLC action therefore consists of how it could gain access to the VSG in the exoplasmic leaflet of the membrane. The data presented herewith disclose an unexpected possible solution for this puzzle: upon cell rupture the VSG invades the cytoplasmic face of the plasma membrane which thus becomes double coated. This unusual VSG rearrangement was stable in ruptured plasma membrane from GPI-PLC null mutant trypanosomes but transiently preceded VSG release in wild-type parasites. The formation of double coat membrane (DCM) was independent of the presence or activation of GPI-PLC, occurred both at 4 degrees C and 30 degrees C and was unaffected by the classical inhibitor of VSG release, p-choromercuryphenylsulfonic acid (PCM). DCMs conserved the same coat thickness and association with subpellicular microtubules as in intact cells and were prone to form vesicles following gradual detachment of the latter. Our data also demonstrate that: (i) GPI-PLC expressed by one trypanosome only targets its own plasma membrane, being unable to release VSG of another parasite; (ii) DCMs concomitantly formed from trypanosomes expressing different VSGs do not intermix, an indication that DCM might be refractory to membrane fusion.


Asunto(s)
Membrana Celular/fisiología , Trypanosoma brucei brucei/fisiología , Fosfolipasas de Tipo C/metabolismo , Glicoproteínas Variantes de Superficie de Trypanosoma/genética , Glicoproteínas Variantes de Superficie de Trypanosoma/metabolismo , Animales , Membrana Celular/ultraestructura , Citoplasma/fisiología , Eliminación de Gen , Glicosilfosfatidilinositol Diacilglicerol-Liasa , Glicosilfosfatidilinositoles/metabolismo , Soluciones Hipotónicas , Microtúbulos/fisiología , Microtúbulos/ultraestructura , Fosfatidilinositol Diacilglicerol-Liasa , Trypanosoma brucei brucei/genética , Trypanosoma brucei brucei/ultraestructura , Glicoproteínas Variantes de Superficie de Trypanosoma/análisis
19.
Am J Med Genet ; 87(3): 237-44, 1999 Nov 26.
Artículo en Inglés | MEDLINE | ID: mdl-10564877

RESUMEN

We report on four unrelated Brazilian patients with growth and mental retardation, structural anomalies of the central nervous system (CNS), mainly callosal agenesis, prominent forehead, facial asymmetry, anophthalmia, heminasal a/hypoplasia, preauricular skin tags, structural anomalies of the external ears, and atypical clefting. This combination of anomalies is unique and, to our knowledge, is a previously undescribed syndrome of unknown etiology, although one of the patients was born to a consanguineous couple, suggesting the possibility of autosomal recessive inheritance. Clinical, genetic, and differential diagnosis aspects are discussed.


Asunto(s)
Anomalías Múltiples , Anoftalmos , Región Branquial/anomalías , Sistema Nervioso Central/anomalías , Labio Leporino , Discapacidad Intelectual , Nariz/anomalías , Anomalías Múltiples/genética , Agenesia del Cuerpo Calloso , Anoftalmos/genética , Brasil , Labio Leporino/genética , Consanguinidad , Enanismo/genética , Encefalocele/genética , Femenino , Humanos , Recién Nacido , Discapacidad Intelectual/genética , Imagen por Resonancia Magnética , Masculino , Fenotipo , Síndrome
20.
Am J Med Genet ; 87(1): 72-7, 1999 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-10528252

RESUMEN

We report on 2 unrelated Brazilian patients, born to non-consanguineous parents, both with multiple anomalies including growth and mental retardation, microcephaly, telecanthus, cleft palate, preauricular skin tags/pit, camptodactyly, and foot anomalies. To our knowledge, this is a previously undescribed formal genesis syndrome. Clinical and genetic aspects are discussed.


Asunto(s)
Anomalías Múltiples/patología , Anomalías Múltiples/genética , Adulto , Brasil , Preescolar , Fisura del Paladar/patología , Oído Externo/anomalías , Femenino , Articulaciones de los Dedos/anomalías , Estudios de Seguimiento , Deformidades Congénitas del Pie/patología , Trastornos del Crecimiento/congénito , Humanos , Lactante , Discapacidad Intelectual/patología , Masculino , Microcefalia/patología , Persona de Mediana Edad , Síndrome
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