187 research outputs found
Production of human recombinant proapolipoprotein A-I in Escherichia coli: purification and biochemical characterization
A human liver cDNA library was used to isolate a clone coding for apolipoprotein A-I (Apo A-I). The clone
carries the sequence for the prepeptide (18 amino acids), the propeptide (6 amino acids), and the mature protein
(243 amino acids). A coding cassette for the proapo A-I molecule was reconstructed by fusing synthetic
sequences, chosen to optimize expression and specifying the amino-terminal methionine and amino acids -6
to +14, to a large fragment of the cDNA coding for amino acids 15-243. The module was expressed in
pOTS-Nco, an Escherichia coli expression vector carrying the regulatable X P^ promoter, leading to the production
of proapolipoprotein A-I at up to 10% of total soluble proteins. The recombinant polypeptide was
purified and characterized in terms of apparent molecular mass, isoelectric point, and by both chemical and
enzymatic peptide mapping. In addition, it was assayed in vitro for the stimulation of the enzyme lecithin:
cholesterol acyltransferase. The data show for the first time that proapo A-I can be produced efficiently in
E. coli as a stable and undegraded protein having physical and functional properties indistinguishable from
those of the natural product
Difference fourier transform infrared evidence for ester bound linking the heme group in myeloperoxidase, lactoperoxidase, and eosinophil peroxidase
Different effects by sex on hypothalamic-pituitary axis of prepubertal offspring rats produced by in utero and lactational exposure to di-(2-ethylhexyl) phthalate (DEHP)
This study investigated the effect of pre and perinatal exposure to di-(2-ethylhexyl) phthalate (DEHP) on the neuroendocrine parameters that regulate reproduction in prepubertal male and female rats. DEHP at doses of 3 and 30 mg/kg. bw/day was administered orally in the drinking water to dam rats since pregnancy onset until the moment of pups sacrifice at 15 days of age. In these animals gonadotropin serum level and the hypothalamic contents of the amino acids aspartate, glutamate and gamma-aminobutyric acid were determined. No changes in gonadotropin levels and amino acid neurotransmitters were detected at the low dose in both sexes. However, DEHP administered at high dose (30 mg/kg bw/day) to dams produced a significant decrease in the inhibitory neurotransmitter GABA and an increase in the stimulatory neurotransmitter aspartate in prepubertal male offspring rats. These modifications were accompanied by gonadotropin serum levels increase. On the contrary, in treated female rats this chemical increased both, aspartate and GABA, which exert a characteristic stimulatory action on gonadotropin in 15-day-old normal females. This study provides new data about changes produced by DEHP on the hypothalamic amino acid neurotransmitters involved in the neuroendocrine reproductive regulation, in prepubertal male and female rat offspring from dams exposed during gestational and lactational periods. These alterations induced by DEHP exposure could be related to the gonadotropin modifications also described in this work, and with changes in the production of sexual hormones previously reported by other authors.Fil: Carbone, Silvia Elena. Universidad Favaloro; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Samaniego, Yanina A.. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Cutrera, Rodolfo Angel. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Reynoso, R.. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Cardoso, N.. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Scacchi, Pablo. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Pontificia Universidad Católica Argentina "Santa MarÃa de los Buenos Aires"; ArgentinaFil: Moguilevsky, Jaime Alberto. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentina. Universidad Favaloro; ArgentinaFil: Ponzo, Osvaldo Juan. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina; Argentin
Temporal Dissociation between Myeloperoxidase (MPO)-Modified LDL and MPO Elevations during Chronic Sleep Restriction and Recovery in Healthy Young Men
OBJECTIVES: Many studies have evaluated the ways in which sleep disturbances may influence inflammation and the possible links of this effect to cardiovascular risk. Our objective was to investigate the effects of chronic sleep restriction and recovery on several blood cardiovascular biomarkers. METHODS AND RESULTS: Nine healthy male non-smokers, aged 22-29 years, were admitted to the Sleep Laboratory for 11 days and nights under continuous electroencephalogram polysomnography. The study consisted of three baseline nights of 8 hours sleep (from 11 pm to 7 am), five sleep-restricted nights, during which sleep was allowed only between 1 am and 6 am, and three recovery nights of 8 hours sleep (11 pm to 7 am). Myeloperoxidase-modified low-density lipoprotein levels increased during the sleep-restricted period indicating an oxidative stress. A significant increase in the quantity of slow-wave sleep was measured during the first recovery night. After this first recovery night, insulin-like growth factor-1 levels increased and myeloperoxidase concentration peaked. CONCLUSIONS: We observed for the first time that sleep restriction and the recovery process are associated with differential changes in blood biomarkers of cardiovascular disease
Endocrine disruptors
An endocrine disruptor (ED) is a synthetic chemical that when absorbed into the body either mimics or blocks hormones and disrupts the body's normal functions. This disruption can happen through altering normal hormone levels, halting or stimulating the production of hormones, or changing the way hormones travel through the body, thus affecting the functions that these hormones control. Chemicals known to be human ED include diethylstilbestrol (DES), dioxin, PCBs, DDT, and other pesticides. Many chemicals, particularly cosmetics (UV filters) and plasticizers, are suspected to be endocrine disruptors based on experimental studies in animals.Sociedad Argentina de FisiologÃ
Structural and biological properties of human recombinant myeloperoxidase.In : The Peroxidase Multigene Family of Enzymes : Biochemical Basis and Clinical Applications
Structural and biological properties of human recombinant myeloperoxidase.In : The Peroxidase Multigene Family of Enzymes : Biochemical Basis and Clinical Applications
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