RESUMEN
Bioaccumulation of lead during chronic exposure and its mobilization and secretion with mother's milk constitute a serious health hazard to the newly born children. Lead levels in human breast milk of 120 Egyptian women representing 20 different governorates throughout Egypt were determined using a graphite furnace Atomic Absorption spectrometer. According to the daily permissible intake (DPI) value established by the WHO of 5.0 micrograms/kg/d in mother's milk, the mean values of lead were around the permissible level in most of the Egyptian governorates. However, lead levels in mother's milk from Alexandria, Assiut and Cairo were significantly higher than the permissible value. Higher lead levels in mother's milk from these governorates may be attributed to heavy automobile traffic using leaded gasoline in addition to the use of lead water pipelines in these areas.
Asunto(s)
Plomo/análisis , Leche Humana/química , Adulto , Egipto , Femenino , Humanos , Espectrofotometría AtómicaRESUMEN
The organochlorine insecticide residues in 60 human milk samples from 20 Egyptian governorates were analyzed by gas chromatography/electron capture and gas chromatography/mass spectrometry. The results showed that the main detected organochlorine insecticides were p,p'-DDE and lindane. Other HCH isomers, p,p'-DDT and endosulfan I residues were detected in some samples, but aldrin and endrin were not detected in most of the samples. The mean values for p,p'-DDE, lindane, endosulfan I and p,p'-DDT levels in the milk samples of the 20 governorates studied were 21.37 ppb, 8.42 ppb, 4.84 ppb and 2.93 ppb respectively, which are lower than the levels reported, a number of years ago, in most of the developed countries. Relatively higher levels of organochlorine insecticide residues were recorded in the samples from intensive agricultural activity regions.
Asunto(s)
Hidrocarburos Clorados , Insecticidas/análisis , Leche Humana/química , Residuos de Plaguicidas/análisis , Cromatografía de Gases , Egipto , Femenino , Cromatografía de Gases y Espectrometría de Masas , Humanos , Lactancia , EmbarazoRESUMEN
Human serum transferrin (HSTF), human serum albumin (HSA) and rat serum were compared for their interaction with AlCl3, in a Tris-HCl buffer solutions (pH 7.4). The AlCl3 was tested in series of concentrations in the range of 50 microM up to 500 microM. HSTF, HSA and their 1:1 mixture and rat serum were incubated at 37 degrees C with series of AlCl3 concentrations. The protein profile of the incubated solutions were compared to control using SDS-PAGE and FPLC tests. The results indicated that HSTF was more specifically responsive to AlCl3 showing a characteristic increase in its UV absorption, peak and area dimensions. Simultaneously, HSA was less affected, but it showed a significant shift with an increase in molecular weight accompanied with a change in its profile. The respective bands of transferrin and albumin in rat serum behaved similarly. The SDS-PAGE and FPLC data coincided and confirmed the preferential affinity of HSTF to bind with Al3+. These results support the suggestion of using HSTF for monitoring levels of Al3+ in human blood samples of exposed population. The importance of further developing such a biomarker is the increased demand for early detection of the hazardous levels of Al3+ in relation to its long term neurotoxic adverse effects.
Asunto(s)
Compuestos de Aluminio/sangre , Proteínas Sanguíneas/metabolismo , Cloruros/sangre , Exposición a Riesgos Ambientales , Albúmina Sérica/metabolismo , Transferrina/metabolismo , Cloruro de Aluminio , Animales , Biomarcadores/sangre , Cromatografía Liquida , Electroforesis en Gel de Poliacrilamida , Humanos , Focalización Isoeléctrica , Unión Proteica , Ratas , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Espectrofotometría UltravioletaRESUMEN
Incubation of purified recombinant human tau protein with aluminum salts at concentrations > or = 100 microM induces aggregation of tau that prevents its entry into SDS-polyacrylamide gels and filtration through nylon membranes. This effect is noncovalent and can be reversed by addition of EDTA. However, when incubated along with ATP, GTP, or CTP, aluminum catalyzes a covalent linkage that results in incorporation of the alpha- and gamma-phosphates into the tau protein (phospho-incorporation). The sensitivity to phosphatases and partial hydrolysis and the labeling observed with ATP containing radioisotopes at different positions suggest a novel reaction in which the entire triphosphate moiety is transferred from ATP and linked to tau via an O-linkage to the alpha-phosphate. The aggregation and triphosphorylation phenomena were not catalyzed by divalent or quadrivalent cations, but similar effects were observed with some other trivalent cations. They occurred at aluminum concentrations similar to those found in human brains with Alzheimer's disease, suggesting the possibility that related reactions may have physiological significance in vivo.
Asunto(s)
Compuestos de Aluminio , Aluminio/farmacología , Cloruros/farmacología , Zinc/metabolismo , Proteínas tau/metabolismo , Adenosina Trifosfato/metabolismo , Cloruro de Aluminio , Caseínas/metabolismo , Ácido Edético/farmacología , Electroforesis en Gel de Poliacrilamida , Humanos , Cinética , Peso Molecular , Fosfopiruvato Hidratasa/metabolismo , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Albúmina Sérica/metabolismo , Proteínas tau/aislamiento & purificaciónRESUMEN
The effects of parathion on male rat pineal N-acetyltransferase (NAT) activity, hydroxyindole-O-methyltransferase (HIOMT) activity and pineal and serum melatonin levels at the end of light period (2000 h) and at night (2300 h and 0100 h) were studied. Additionally, pineal levels of 5-hydroxytryptophan (5-HTP), serotonin (5-HT), and 5-hydroxyindole acetic acid (5-HIAA) were estimated. Parathion was administered intragastrically at total doses (over 6 days) of either 6.5 or 13 mg/kg. Control rats received vehicle (corn oil) only. During the study, the rats were exposed to light:dark cycles of 14:10 with light off at 2100 h. Pineal NAT activity was increased at 0100 h following parathion administration at both doses, but HIOMT activity was unaffected. Pineal and serum melatonin levels were increased at night (2300 h and 0100 h) after the 13 mg/kg dose of parathion while the lower dose increased pineal melatonin only at 0100 h. Also, both doses decreased 5-HTP at 2000 h while the lower dose increased it at 2300; 5-HT was significantly decreased at 2300 h and 5-HIAA levels were lower but only significantly so for the 13 mg/kg dose at 2000 h. The results indicate that parathion has significant effects on pineal melatonin synthesis by mechanisms which remain unknown.
Asunto(s)
Acetilserotonina O-Metiltransferasa/metabolismo , Arilamina N-Acetiltransferasa/metabolismo , Ritmo Circadiano/efectos de los fármacos , Melatonina/biosíntesis , Paratión/farmacología , Glándula Pineal/fisiología , Animales , Ácido Hidroxiindolacético/metabolismo , Masculino , Melatonina/sangre , Glándula Pineal/efectos de los fármacos , Glándula Pineal/metabolismo , Ratas , Ratas Endogámicas , Serotonina/metabolismoRESUMEN
The purpose of this study was to examine the effects of chronic administration of sublethal doses of carbaryl on pineal melatonin synthesis. N-methyl 1-naphthylcarbamate (carbaryl) (8.33 mg/kg B.W. daily) was administered orally to adult male albino rats for 6 successive days. Nocturnal (0100) N-acetyltransferase and hydroxyindole-O-methyltransferase activities were increased (roughly 75% and 60%, respectively) by carbaryl administration; likewise, carbaryl augmented serum melatonin levels at 2300. Pineal tryptophan. 5-hydroxytryptophan, serotonin, and 5-hydroxindole acetic acid levels were unaffected at all three time points. The results indicate that the carbamate pesticide, i.e., carbaryl, modifies pineal melatonin synthesis in vivo.
Asunto(s)
Acetilserotonina O-Metiltransferasa/metabolismo , Arilamina N-Acetiltransferasa/metabolismo , Carbaril/toxicidad , Melatonina/sangre , Glándula Pineal/efectos de los fármacos , 5-Hidroxitriptófano/metabolismo , Administración Oral , Animales , Carbaril/administración & dosificación , Ácido Hidroxiindolacético/metabolismo , Masculino , Glándula Pineal/enzimología , Radioinmunoensayo , Ratas , Serotonina/metabolismo , Estadística como Asunto , Triptófano/metabolismoRESUMEN
Two spraymen working in public health occupations in Alexandria, Egypt, experienced acute toxicity resulting from exposure to diazinon. Symptomatology was similar to that previously reported for exposure to parathion or other organophosphorus insecticides. Plasma and red blood cell cholinesterase activity values were determined in blood samples obtained from both individuals at various times after the incident. Cholinesterase activity showed a marked reduction up to 18 days after exposure. Blood cholinesterase activity recovered to approximately 90% of the normal level of activity 28 days after the poisoning incident in one individual. This activity recovered to about the same level in the other individual, but after only 20 days from the poisoning date. Experimental results suggested that this acute toxicity resulted from unsuitable storage conditions of the emulsifiable concentrate formulation of diazinon. The diazinon that was applied was stored in "tin" containers made of tin-plated sheet steel. The emulsifiable concentrate (60%) was not in compliance with the World Health Organization's standard specifications regarding the emulsion stability tests because of the presence of crystals in the emulsifiable concentrate. A sample of this crystalline material was analyzed. Gas chromatographic analysis combined with mass spectrometric techniques failed to identify intact diazinon in samples of that material. The sample represented virtually complete conversion of diazinion into transformation products. Sulfotepp and monothiono-TEPP were two of the identified products in the sample, both of which are much more toxic than diazinon.
Asunto(s)
Diazinón/envenenamiento , Insecticidas/envenenamiento , Adulto , Fenómenos Químicos , Química , Colinesterasas/sangre , Diazinón/análisis , Embalaje de Medicamentos , Egipto , Cromatografía de Gases y Espectrometría de Masas , Humanos , Masculino , Persona de Mediana Edad , Enfermedades Profesionales/inducido químicamenteRESUMEN
A direct photometric method for assaying neurotoxic esterase (NTE) activity of chicken brain microsomal preparation has been developed using 4-nitrophenyl esters as substrates. Paired samples of the microsomal preparation were preincubated for 20 min with paraoxon plus either (a) buffer or (b) mipafox before addition of substrate. The initial rate of NTE activity was directly recorded at 410 nm by matching the content of tube (a) against tube (b) after addition of the substrate to both of them. The 4-nitrophenyl esters of propionic, butyric, valeric, lauric, capric and caproic acids were tested as substrates. Results indicated that 4-nitrophenyl valerate and caproate, respectively, are the most hydrolyzable substrates for NTE with this method; its also enables detailed kinetic studies of NTE to be made. The Michaelis constant (Km) for the hydrolysis of 4-nitrophenyl valerate by NTe was found to be 5.55 . 10(-5) M.