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1.
Int J Trichology ; 11(3): 101-106, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31360037

RESUMO

Androgenetic alopecia (AGA), also known as androgenic or pattern alopecia, is a frequently reported disorder that affects both the sexes, with a higher incidence generally reported in men. AGA has immense psychological effects on the patient, irrespective of the age or stage of baldness. This consensus document has been developed taking into account the opinions of leading experts in the field of dermatology. The objective of this article is to provide the dermatologists with an evidence-based platform for choosing efficacious and safe therapy for patients with AGA. This review articulately summarizes the key opinions of the experts on all aspects of treatment for the effective management of AGA.

2.
Int J Trichology ; 11(3): 107-112, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31360038

RESUMO

Alopecia, a frequently reported problem, severely impacts the quality of life of patients and is often associated with loss of confidence and low self-esteem. Several conditions such as telogen effluvium (TE), anagen effluvium, diffuse type of alopecia areata, female pattern hair loss, hair shaft abnormalities, loose anagen hair syndrome, and congenital atrichia or hypotrichosis are associated with hair loss. The actual prevalence rate of TE is not reported since most cases are subclinical in nature. Further, since women get more distressed by hair fall and promptly seek treatment, they tend to be over-represented. However, both genders can suffer from this condition if triggering factors are present. This consensus paper was developed by taking into account opinions of renowned experts in the field and is hoped to serve as an evidence-based platform for selecting efficacious and safe therapy for patients with TE. This review presents a synopsis of the key opinions of experts on all aspects of treatment and effective management of this condition.

3.
J Colloid Interface Sci ; 320(1): 245-53, 2008 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-18243234

RESUMO

Phase inversion method is applied to prepare flat sheet asymmetric polymeric membranes from homogeneous solution of 12 wt% polysulfone (PSf) with two different solvents--N-methyl-2-pyrrolidone (NMP) and dimethyl acetamide (DMAc). 5.0 wt% polyethylene glycol (PEG) of three different molecular weight (400, 6000, and 20,000 Da) is used as the polymeric additives in the casting solution. Membranes are characterized by two different techniques viz. scanning electron microscopy (SEM) and gas permeation tests. Finally, the results of both the techniques are compared with those calculated from pure water permeation tests using Hagen-Poiseuille equation. It is found that though the values obtained from all the techniques vary from each other, their trend with increase in molecular weight of PEG seems to be the same. It is seen that when molecular weight of PEG increases from 400 to 20,000 Da, the mean pore size of the prepared membranes decreases, while the porosity and pore density show an increasing trend; the pressure normalized gas flux rises significantly and the thickness of the top layer of the prepared membrane sheet increases.

4.
Bioresour Technol ; 99(9): 3765-73, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17714943

RESUMO

A mathematical model consisting of mass balance equations and accounting for bioreaction and mass transfer is presented to describe both unsteady and steady-state degradation of phenol in a biofilter. The model has been validated for the steady-state situation with literature work. The model has been able to predict the dynamics of the biofiltration process with variations in system and operating conditions as inlet substrate concentration, liquid phase mass transfer coefficients, particle size, Henry's constant, inlet velocity, growth and half saturation constants and bed void fraction. The results show that inlet substrate concentration, inlet velocity, growth and half saturation constants and liquid phase mass transfer coefficients significantly control the operational dynamics. It is also shown that inhibition effects can be neglected for low concentrations (<0.5 kg m(-3)) of phenol. Thus, the model can be used as a design tool for a biofilter.


Assuntos
Simulação por Computador , Modelos Teóricos , Microbiologia da Água , Purificação da Água/instrumentação , Purificação da Água/métodos , Biodegradação Ambiental , Biomassa , Cinética , Tamanho da Partícula , Reprodutibilidade dos Testes
5.
Environ Technol ; 26(12): 1403-10, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16372575

RESUMO

Equilibrium adsorption isotherms of As(III) were obtained from the experimentally generated data on activated alumina and activated carbon at temperature 303 K and pH 7.4. The isotherm for As(III) on activated alumina was typically of Brunauer Type-I but in the case of activated carbon equilibrium capacity seems to be increasing with increase in concentration. Langmuir isotherm model best represents the experimental data for As(III) in activated alumina and Freundlich model in activated carbon. Model parameters such as saturation capacity of adsorbent qs, Langmuir constant b, and Freundlich constants K and n were determined. Saturation adsorption capacity of As(III) in activated carbon was much higher than that in activated alumina. Overall effective mass transfer coefficient k was determined using uptake rate method. It is observed that k was independent of concentration of As(III). Values of k for both the adsorbents are of the order of 10(-2) min(-1).


Assuntos
Óxido de Alumínio/química , Arsenitos/isolamento & purificação , Carvão Vegetal/química , Eliminação de Resíduos Líquidos/métodos , Purificação da Água/métodos , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Temperatura
6.
Proc Soc Exp Biol Med ; 225(2): 128-35, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11044255

RESUMO

The insulin-like growth factors (IGFs) are mitogenic polypeptides that have been linked to a variety of normal physiological processes as well as neoplasia. Overexpression of several components of the IGF system is associated with hepatocarcinogenesis in humans and rodents. In rat liver, diets rich in n-6 polyunsaturated fatty acid (PUFA) enhance the development of preneoplastic lesions and tumors. Therefore, the objective of this study was to determine the effect of these dietary fatty acids on the hepatic expression of the various components of the IGF system. The mRNA levels of IGF-1 and the type 1 receptor were not different in livers of rats fed a diet containing 20% corn oil (CO) compared with those fed 5% CO. Analysis of the IGF binding proteins revealed that insulin-like growth factor binding protein-1 (IGFBP-1) levels were altered by the amount and type of dietary fat. A 2.5-fold induction of IGFBP-1 mRNA occurred within 1 week after the animals were fed the 20% corn oil diet compared with those fed 5% CO and was further enhanced to over 6-fold after 1 month. Furthermore, IGFBP-1 protein was only detectable in the livers of animals fed the 20% CO diet. Induction of IGFBP-1 mRNA (4.5-fold) also occurred in rats fed a high-fat diet containing safflower (rich in n-6 PUFAs) compared with those fed a high-fat diet containing menhaden oil (rich in n-3 PUFAs). The induction of IGFBP-1 mRNA was independent of serum insulin levels and the development of insulin resistance. Since IGFBP-1 mRNA is upregulated in regenerating liver, we reasoned that the induction of IGFBP-1 mRNA may be associated with an increase in cell proliferation; however, no difference was observed in the hepatic labeling index of rats fed the 20% CO compared with the 5% CO diet. In summary, these studies show a striking induction by dietary n-6 PUFAs of hepatic IGFBP-1, a protein that has been implicated in liver cancer development.


Assuntos
Gorduras Insaturadas na Dieta/toxicidade , Ácidos Graxos Insaturados/toxicidade , Proteína 1 de Ligação a Fator de Crescimento Semelhante à Insulina/biossíntese , Fígado/efeitos dos fármacos , Fígado/metabolismo , Animais , Divisão Celular/efeitos dos fármacos , Ácidos Graxos Ômega-6 , Feminino , Hepatócitos/citologia , Hepatócitos/efeitos dos fármacos , Humanos , Insulina/sangue , Resistência à Insulina , Proteína 1 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Proteína 4 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like II/genética , Neoplasias Hepáticas Experimentais/etiologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley
7.
Biochem Biophys Res Commun ; 261(3): 676-81, 1999 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-10441485

RESUMO

A peptide fragment comprising the first 83 residues from the N-terminus of E. coli thioredoxin is purified by hydroxylamine cleavage of the intact protein. At physiological pH, the secondary and tertiary structure contents of the peptide are 70 and 35%, respectively, compared to the intact protein. Peptide 83 is able to display dual biological functions of thioredoxin, namely, a substrate for the enzyme E. coli thioredoxin-reductase and a processivity factor of T7 DNA polymerase. At present, peptide 83 represents the minimum functional and folding unit of thioredoxin. The highly conserved residue Phe 81 appears to play an important role in the folding of peptide 83, as judged from the packing analysis. Peptide 83 also mimics a particular kinetic folding intermediate of thioredoxin in terms of spectral properties and may serve as an equilibrium peptide model for the former.


Assuntos
Escherichia coli/química , Fragmentos de Peptídeos/química , Dobramento de Proteína , Tiorredoxinas/química , Naftalenossulfonato de Anilina , Dicroísmo Circular , Ácido Ditionitrobenzoico/química , Ditiotreitol/química , Corantes Fluorescentes , Concentração de Íons de Hidrogênio , Modelos Moleculares , Fragmentos de Peptídeos/metabolismo , Fenilalanina/química , Espectrometria de Fluorescência , Reagentes de Sulfidrila/química , Tiorredoxina Dissulfeto Redutase/metabolismo , Tiorredoxinas/metabolismo , Triptofano/química
8.
Biochem J ; 339 ( Pt 3): 721-7, 1999 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-10215612

RESUMO

Escherichia coli thioredoxin was cleaved with CNBr at its single Met residue at position 37, which lies in the middle of a long alpha-helix. The two fragments, 1-37 and 38-108, were purified and characterized by using CD and fluorescence spectroscopy. Both fragments lack structure at neutral pH and room temperature. The secondary and tertiary structural contents of the non-covalent complex formed on the mixing of the two peptide fragments are 47% and 35% of the intact protein respectively. The thermodynamics and kinetics of fragment association were characterized by titration calorimetry and stopped-flow fluorescence spectroscopy. Single phases were observed for both association and dissociation, with rate constants at 298 K of kon=4971+/-160 M-1.s -1 and koff=0. 063+/-0.009 s-1 respectively. The ratio kon/koff was very similar to the binding constant determined by titration calorimetry, suggesting that binding is a two-state process. The values for DeltaCp, DeltaH0 and DeltaG0 at 298 K for dissociation of the complex were 5.7 kJ. mol-1.K-1, 45.3 kJ.mol-1 and 29.8 kJ.mol-1 respectively. The value for DeltaH0 was linearly dependent on temperature from 8-40 degrees C, suggesting that DeltaCp is independent of temperature. The values for DeltaCp and DeltaG0 are very similar to the corresponding values for the unfolding of intact thioredoxin at 25 degrees C. However, both DeltaH0 and DeltaS are significantly more positive for dissociation of the complex, suggesting a decreased hydrophobic stabilization of the complex relative to the situation for intact thioredoxin.


Assuntos
Escherichia coli/metabolismo , Fragmentos de Peptídeos/metabolismo , Dobramento de Proteína , Tiorredoxinas/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Calorimetria , Cromatografia em Gel , Dicroísmo Circular , Brometo de Cianogênio/metabolismo , Escherichia coli/química , Concentração de Íons de Hidrogênio , Cinética , Fragmentos de Peptídeos/química , Ligação Proteica , Estrutura Secundária de Proteína , Espectrometria de Fluorescência , Temperatura , Termodinâmica , Tiorredoxinas/química , Titulometria , Triptofano/química , Triptofano/metabolismo , Tirosina/química , Tirosina/metabolismo
10.
Carcinogenesis ; 19(5): 905-10, 1998 May.
Artigo em Inglês | MEDLINE | ID: mdl-9635881

RESUMO

Dietary n-6 polyunsaturated fatty acids (PUFAs) promote rat mammary cancer while n-3 PUFAs are inhibitory. The purpose of this study was to determine whether the fats exert their effects by altering the expression of genes that affect cancer development. Therefore, we have examined the effect of PUFAs on the expression of the cyclooxygenase (COX) 1 and 2 genes that are involved in prostaglandin biosynthesis. We also investigated the effect of dietary PUFAs on the expression of the p21ras protein and Ha-ras mRNA. Rats were fed either low- (7%; LF) or high- (21%; HF) fat diets that were rich in either n-6 PUFAs (safflower oil, S) or n-3 PUFAs (menhaden oil, M) for 3 weeks. COX-1 mRNA levels were approximately the same in groups fed diets containing either level of menhaden oil, but were increased by approximately 30% in the LFS and HFS groups (P < 0.05). Transcripts of the inducible COX-2 gene were not detectable in the menhaden oil groups, but this gene was expressed in animals fed either level of safflower oil and in the HFS group was associated with increased levels of COX enzymatic activity and production of PGE2. Animals fed safflower oil had elevated levels of p21ras protein compared to animals fed menhaden oil. Ha-ras mRNA was increased by approximately 35% in animals fed HFS compared to the group fed HFM (P < 0.05). These results demonstrate that dietary n-6 PUFAs upregulate COX-2 and, to some extent, COX-1 expression. There was a concomitant increase in COX enzyme activity and PG synthesis in the mammary glands of rats fed high levels of n-6 PUFAs. Together with associated changes in p21ras expression, these results may explain, at least in part, the promoting effects of dietary n-6 PUFAs on mammary carcinogenesis.


Assuntos
Gorduras na Dieta/farmacologia , Ácidos Graxos Insaturados/farmacologia , Isoenzimas/genética , Glândulas Mamárias Animais/efeitos dos fármacos , Proteína Oncogênica p21(ras)/genética , Prostaglandina-Endoperóxido Sintases/genética , Animais , Sequência de Bases , Ciclo-Oxigenase 1 , Ciclo-Oxigenase 2 , Primers do DNA , Dinoprostona/metabolismo , Feminino , Genes ras , Glândulas Mamárias Animais/metabolismo , Proteínas de Membrana , Proteína Oncogênica p21(ras)/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley
11.
Lipids ; 30(10): 959-61, 1995 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8538385

RESUMO

The effect of age and peroxidative stress on the concentration of a deoxyguanosine malondialdehyde adduct (dG-MDA) in rat tissues was investigated. Vitamin E deficiency had no effect on the dG-MDA content of liver DNA in rats fed a diet containing 10% corn oil. When 2% cod liver oil was added to this diet, the dG-MDA content of liver DNA doubled in the positive controls fed a high level of vitamin E (100 ppm dl-alpha-tocopherol), and there was a further increase when vitamin E was deleted. Neither iron nitrilotriacetate administration nor choline deficiency had any effect on the dG-MDA content of liver DNA. Carbon tetrachloride had a lowering effect. The failure of iron or carbon tetrachloride administration and of vitamin E deficiency to increase liver dG-MDA is consistent with their failure in previous experiments to affect the urinary excretion of dG-MDA. In contrast, these forms of peroxidative stress produce large increments in the urinary excretion of MDA adducts with lysine, reflecting increased formation and degradation of MDA-modified proteins. DNA appears to be protected from modification by MDA produced at extranuclear sites. The frequency of dG-MDA in different tissues of 4-month-old rats varied markedly: brain >> liver > kidneys and testes. Higher concentrations of dG-MDA were found in the liver and kidneys, but not the testes, of 25-month-old rats. The determinants of the concentration of dG-MDA in DNA merit further investigation.


Assuntos
Envelhecimento , Adutos de DNA/análise , Desoxiguanosina/análise , Malondialdeído/análise , Estresse Oxidativo , Animais , Química Encefálica , Tetracloreto de Carbono/farmacologia , Óleo de Fígado de Bacalhau/administração & dosagem , Óleo de Milho/administração & dosagem , DNA/análise , DNA/metabolismo , Desoxiguanosina/metabolismo , Gorduras Insaturadas na Dieta/administração & dosagem , Rim/química , Fígado/química , Fígado/efeitos dos fármacos , Masculino , Malondialdeído/metabolismo , Ratos , Testículo/química , Vitamina E/administração & dosagem , Deficiência de Vitamina E/metabolismo
12.
Histol Histopathol ; 10(2): 457-62, 1995 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-7599441

RESUMO

New information on the pathologic effects of a choline deficient diet in the rat, in relation to the biochemical events, has led to a new understanding and orientation of the pathogenesis of both acute and chronic consequences in the liver. The biochemical pathology of choline deficiency is quite different than that of methyl group (lipotrope) deficiency. These studies in our laboratory and elsewhere are generating new insights and hypotheses concerning the genesis of hepatocyte necrosis and hepatocellular carcinoma in the rat fed a choline deficient diet.


Assuntos
Deficiência de Colina/patologia , Peroxidação de Lipídeos/fisiologia , Fígado/patologia , Animais , Deficiência de Colina/metabolismo , Dieta , Humanos , Fígado/metabolismo , Metilação
13.
Crit Rev Biochem Mol Biol ; 30(4): 263-73, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-7587279

RESUMO

A diet deficient in choline can cause liver cancer in rats. The previous work since 1932 emphasized the fat-removing ability of choline from the liver. There are other dietary factors, including methionine, which, like choline, can remove fat from the liver. These factors were termed as lipotropes. Since then, choline deficiency and lipotrope deficiency are used synonoumously. Recent work since 1980 has clearly demonstrated that choline deficiency (CD) and lipotrope deficiency (LD) are not the same. Generation of free radicals, DNA alterations, liver cell death, and liver cancer that occur due to CD are not generated by LD. Generation of free radicals due to CD diet and some of the agents that counteract free radical action also prevent CD effects except for lipid accumulation in the liver. Despite the recent observations on the role of phospholipase A2 (PLA2) as the protector of the membranes, it has been found that by preventing the rise of PLA2 in the liver, cell death can be prevented. These new findings give choline a distinct role in liver cell death and cancer rather than the role of lipotrope. A new hypothesis linking dietary choline deficiency and liver cancer has been discussed.


Assuntos
Deficiência de Colina/metabolismo , Fígado/metabolismo , Animais , Cálcio/farmacologia , Morte Celular , Deficiência de Colina/patologia , Dieta/efeitos adversos , Radicais Livres/metabolismo , Humanos , Metabolismo dos Lipídeos , Peroxidação de Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/patologia , Neoplasias Hepáticas/etiologia , Modelos Biológicos , Fosfolipases A/metabolismo , Fosfolipases A2 , Ratos , Estrôncio/farmacologia
14.
Toxicol Appl Pharmacol ; 124(1): 139-48, 1994 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8291055

RESUMO

Levels of various cytochrome P450 proteins have been reported to be decreased to varying degrees in chemically induced hepatocyte nodules and following partial hepatectomy (PH). By screening a rat liver lambda ZAP cDNA expression library with antibodies raised against a partially purified preparation of cytochrome P450 isolated from untreated male Fischer 344 rats, we have isolated a 1.1-kb cDNA. This cDNA was sequenced for 139 bases from the 5' end of the sense strand and comparison of the resulting sequence with the sequences in Gene Man DNA data bank revealed 95% homology of the sequenced portion with male-specific rat cytochrome P450 (M-1, CYP IIC11). The 32P-labeled cDNA was used as a hybridization probe on RNA blots (Northern blots) prepared with total RNA from rat livers obtained post PH, from aflatoxin B1(AFB1)-induced rat liver tumors and from rat liver nodules induced with a combination of diethylnitrosamine/acetylaminofluorene/PH (DEN/AFF/PH). At 36 and 72 hr post PH, the mRNA level was decreased by > 93%. Relative to the corresponding control livers, the mRNA level was also decreased by 97% in the liver nodules and by 57% in AFB1-induced liver tumors. The RNA blots derived from the liver nodules and AFB1-induced liver tumors were also probed with a cDNA probe (R17) that recognizes other cytochromes P450 (CYP IIB1/CYP IIB2). The mRNA corresponding to CYP IIB1/CYP IIB2 was also depressed 92% in the nodules and 65% in the tumors. These results clearly indicate that the depression of both CYP IIC11 and IIB1/IIB2 in the hepatic nodules and the tumors is related to the inhibition of transcription and/or enhanced degradation of the mRNA.


Assuntos
Sistema Enzimático do Citocromo P-450/biossíntese , Neoplasias Hepáticas Experimentais/enzimologia , Fígado/enzimologia , RNA Mensageiro/análise , Animais , Sequência de Bases , Sistema Enzimático do Citocromo P-450/isolamento & purificação , Expressão Gênica , Hepatectomia , Fígado/cirurgia , Masculino , Microssomos Hepáticos/enzimologia , Dados de Sequência Molecular , Ratos , Ratos Endogâmicos F344
15.
Lab Invest ; 68(3): 255-60, 1993 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-7680728

RESUMO

Thus, the pathologic consequences of feeding a CD diet are fatty liver, liver cell death, liver cell proliferation, and liver cell cancer. The fatty liver with CD is similar to that with other types of fatty liver in that the most attractive current hypothesis is based on some interference with the production and output of VLDL by the liver. The induction of cell death appears to be consistent with quite a different hypothesis, genesis and/or increase in liver free radicals leading to both acute necrosis and initiation of carcinogenesis. Especially noteworthy is the low incidence of liver cirrhosis, even after 2 years of exposure to the CD diet. The feeding of the CD diet reproducibly induces severe and persistent fatty liver coupled with extensive cell death, a combination that is frequently considered to be appropriate for the induction of "micronodular" (fatty) cirrhosis in humans. The findings with the LD diet, the high incidence of cirrhosis, with severe persistent fatty liver without significant cell death, together with the low incidence of cirrhosis with the CD diet, stand out as unpredictable and strange, according to current concepts of the pathogenesis of human cirrhosis. The CD model offers an unusual opportunity to explore in increasing detail the possible roles of free radicals in two important problems in pathology and medicine-acute cell injury and neoplasia. The challenges include mechanistic studies on how the free radicals are generated and how they relate to the biological consequences. The relatively slow sequential changes in the induction of cell injury and neoplasia makes the CD model one of the best for mechanistic studies relating to free radicals.


Assuntos
Carcinoma Hepatocelular/etiologia , Deficiência de Colina/complicações , Lipotrópicos/metabolismo , Hepatopatias/etiologia , Neoplasias Hepáticas/etiologia , Doenças Metabólicas/complicações , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/fisiopatologia , Deficiência de Colina/metabolismo , Deficiência de Colina/fisiopatologia , Humanos , Hepatopatias/metabolismo , Hepatopatias/fisiopatologia , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/fisiopatologia , Doenças Metabólicas/metabolismo , Doenças Metabólicas/fisiopatologia , Síndrome
16.
Lipids ; 27(2): 144-6, 1992 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-1579059

RESUMO

Male F-344 rats were fed a choline-free (CF) diet, and changes in phospholipid content, phospholipid fatty acids and phospholipase A2 activity in liver nuclei and microsomes were examined during the first 72 hr. Both nuclei and microsomes showed a decrease in phosphatidylcholine (PC) content. Microsomes showed an increase in PC arachidonate while nuclei showed a decrease. Also, microsomes showed increased activity of phospholipase A2 (PLA2) while nuclei did not. These observations are consistent with the hypothesis that the absence of diene conjugates in liver microsomes in the rats on the CF diet may reflect the increased rate of removal of peroxidized fatty acids by phospholipase A2.


Assuntos
Deficiência de Colina/metabolismo , Ácidos Graxos/análise , Fígado/química , Fosfolipídeos/química , Animais , Núcleo Celular/química , Núcleo Celular/enzimologia , Masculino , Microssomos Hepáticos/química , Membrana Nuclear/química , Fosfolipases A/análise , Fosfolipases A2 , Ratos , Ratos Endogâmicos F344 , Frações Subcelulares/química
17.
Free Radic Biol Med ; 8(1): 3-7, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-2323581

RESUMO

This study was designed to explore the possible preventive effects of a novel radicophile, N-p-methoxyphenylacetyl-dehydroalanine (AD5) and three other antioxidants, N,N'-diphenyl-p-phenylenediamine (DPPD), butylated hydroxyanisole (BHA) and a water-soluble analogue of vitamin E, trolox C, on the acute effects of the liver of feeding a choline-deficient (CD) diet. It has been suggested that some of the acute effects of a CD diet are related to free radicals, the generation or metabolism of which is disturbed in this acute dietary model. AD5 was found to be very effective in preventing nuclear lipid peroxidation, DNA damage and cell death induced by a CD diet but to have little effect on triglyceride accumulation ("fatty liver"). DPPD, BHA, and trolox C were ineffective. These results add strength to the hypothesis that oxygen free radicals might be an important component in the early events during carcinogenesis induced by feeding a CD diet.


Assuntos
Alanina/análogos & derivados , Deficiência de Colina/metabolismo , Fígado/efeitos dos fármacos , Alanina/farmacologia , Animais , Antioxidantes/farmacologia , Hidroxianisol Butilado/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Deficiência de Colina/patologia , Cromanos/farmacologia , DNA/efeitos dos fármacos , Radicais Livres , Peroxidação de Lipídeos/efeitos dos fármacos , Fígado/metabolismo , Masculino , Fenilenodiaminas/farmacologia , Ratos , Ratos Endogâmicos F344
18.
Cancer Lett ; 41(1): 53-62, 1988 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-3390803

RESUMO

Fischer F-344 male rats, fed a choline-devoid diet that leads to a highly reproducible sequence of biochemical and biological changes with an ultimate development of hepatocellular carcinoma, show elevated levels of glutathione in the liver at 3, 6 and 8 days. Several enzymes related to the metabolism of free radicals, including superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase and DT-diaphorase show neither increased nor decreased activity as measured between 12 h and 8 days on the diet. Thus, of several known cellular components related to the possible scavenger of free radicals in the liver, only glutathione responded to the feeding of the CD diet. It is tentatively concluded that a decrease in the levels of possible scavengers for free radicals is not a major basis for the nuclear and mitochondrial lipid peroxidation seen early in rats fed a choline-devoid diet.


Assuntos
Deficiência de Colina/metabolismo , Glutationa/análise , Fígado/metabolismo , Animais , Radicais Livres , Peróxidos Lipídicos/metabolismo , Masculino , Metionina/deficiência , Ratos , Ratos Endogâmicos F344
19.
Cancer Res ; 47(24 Pt 1): 6731-40, 1987 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-3677103

RESUMO

Fischer-344 rats fed a choline-devoid diet show lipid peroxidation in the liver nuclei, beginning at 1 day, reaching a peak at 3 days, and subsequently declining by 35 days. Lipid peroxidation in the mitochondria was seen first at 3 days, increased to a maximum at 28 days, and decreased after 35 days to undetectable values at 49 days. Lipid peroxidation was found in both nuclear and mitochondrial fractions both before and after stripping of their outer membranes. No microsomal lipid peroxidation could be detected at any time up to 63 days. The animals fed the same diet supplemented with choline showed no lipid peroxidation in any liver fraction. Animals given CCl4 showed the expected lipid peroxidation in the microsomes but not in the nuclear fraction. The administration of the free radical trapping agent, N-tert-butyl-alpha-phenylnitrone, prevented completely or almost so, microsomal lipid peroxidation induced by CCl4 and nuclear lipid peroxidation in the animals fed the choline-devoid, low methionine diet. The genesis of free radicals in the livers of rats fed a choline-devoid diet is considered as a likely hypothesis for the observed lipid peroxidation. The lipid peroxidation in turn is considered to be closely related to the induction of liver cell death and to the production of alterations in DNA. The DNA alterations coupled with regenerative liver cell proliferation suggest an attractive hypothesis for the initiation of hepatocarcinogenesis in rats fed a choline-devoid diet.


Assuntos
Deficiência de Colina/complicações , Dieta , Neoplasias Hepáticas Experimentais/etiologia , Fígado/metabolismo , Metionina/administração & dosagem , Aldeídos/metabolismo , Animais , Intoxicação por Tetracloreto de Carbono/metabolismo , Divisão Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Óxidos N-Cíclicos , Dano ao DNA , Radicais Livres , L-Iditol 2-Desidrogenase/sangue , Peróxidos Lipídicos/biossíntese , Masculino , Óxidos de Nitrogênio/farmacologia , Ratos , Ratos Endogâmicos F344
20.
Cancer Lett ; 36(3): 289-96, 1987 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2888529

RESUMO

The feeding for 10 or 11 weeks of young male Fischer-344 rats, a diet devoid of choline and low in methionine, leads to the appearance of gamma-glutamyltransferase-positive foci of altered hepatocytes in the liver and to the induction of initiated resistant hepatocytes. The latter are known to contain the primary precursor cells for the ultimate development of hepatocellular carcinoma. This initiation of carcinogenesis with the choline-devoid diet is prevented by added choline. These observations indicate that a dietary deficiency may, by itself, without known contaminating or added carcinogens, initiate the carcinogenic process.


Assuntos
Deficiência de Colina/complicações , Dieta , Neoplasias Hepáticas Experimentais/etiologia , Animais , Carcinógenos , Proteínas Alimentares/administração & dosagem , Fígado/enzimologia , Neoplasias Hepáticas Experimentais/enzimologia , Masculino , Metionina/deficiência , Ratos , Ratos Endogâmicos F344 , gama-Glutamiltransferase/metabolismo
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