RESUMO
BACKGROUND: Medications that are used for treatment of metabolic disorders have been suggested to be associated with the development of amyotrophic lateral sclerosis (ALS). METHODS: To examine the associations of antidiabetics and statins with the subsequent risk of ALS we conducted a population-based nested case-control study of 2475 Swedish residents diagnosed with ALS during July 2006 to December 2013 and 12 375 population controls (five for each ALS case). We extracted information on filled prescriptions of antidiabetics and statins for both cases and controls from the Swedish Prescribed Drug Register during the years before ALS diagnosis. Conditional logistic regression was used to calculate odds ratios (ORs) for the associations of these medications with ALS risk. RESULTS: Patients with ALS were less likely to have been prescribed with antidiabetics compared with controls [OR, 0.76; 95% confidence intervals (CI), 0.65-0.90]. Conversely, statins were not associated with ALS risk overall (OR, 1.08; 95% CI, 0.98-1.19), although a positive association was noted among women (OR, 1.28; 95% CI, 1.10-1.48). The latter association was mostly explained by ALS cases being more likely to have a first prescription of statins during the year before diagnosis compared with controls (OR, 2.54; 95% CI, 1.84-3.49). CONCLUSIONS: The inverse association of antidiabetics with ALS is consistent with the previously reported inverse association between type 2 diabetes and ALS risk. The increase in prescription of statins during the year before ALS diagnosis deserves attention because it might reflect an acceleration of the course of ALS due to statin use.
Assuntos
Esclerose Lateral Amiotrófica , Esclerose Lateral Amiotrófica/tratamento farmacológico , Esclerose Lateral Amiotrófica/epidemiologia , Estudos de Casos e Controles , Diabetes Mellitus Tipo 2 , Feminino , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Hipoglicemiantes , Fatores de Risco , Suécia/epidemiologiaRESUMO
Biosynthesis silver nanoparticles (AgNPs) have received a lot of attention as a cytotoxic and antimicrobial activity against pathogenic bacteria. This study was carried out to evaluate the potential ability of red marine algae Corallina elongata and Gelidium amansii to biosynthesis AgNPs capping with Sodium Dodecyl Sulfate (SDS) and to determine its antibacterial efficacy. Characterization of capping AgNPs were determined by Ultra violet-Visible spectroscopy, Transmission electron microscope (TEM), Scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), Energy dispersive X-ray spectroscopy (EDX), Zeta potential and sizer. The results indicated that there is no variation change between capping AgNPs synthesis by two red algae in plasmon resonance peak and also both stable along 3 weeks. The capping nanoparticles size were range from 8 to 25â¯nm in the case of G. amansii and 12-20â¯nmâ¯C. elongata. The results were obtained from Fourier transforms infrared spectroscopy (FTIR) indicated that same metals are present in both algae except Vanadium (V) was present with G. amansii. Capping AgNPs biosynthesis by C. elongata had more toxicity to Chlorella vulgaris than that of synthesized by G. amansii. Capping AgNPs by SDS have been shown to enhance antibacterial activity against Micrococcus leutus, Kocuria varians and Escherichia coli ATCC 8739 compared to non-capping AgNPs. The antibacterial activity and toxicity of AgNPs is affected by concentrations of capping agent and the biomaterial (red algae) that used for synthesis.
Assuntos
Antibacterianos/metabolismo , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Nanopartículas Metálicas/química , Rodófitas/metabolismo , Prata/metabolismo , Dodecilsulfato de Sódio/metabolismo , Antibacterianos/química , Estabilidade de Medicamentos , Nanopartículas Metálicas/ultraestrutura , Testes de Sensibilidade Microbiana , Microscopia Eletrônica , Análise Espectral , Ressonância de Plasmônio de SuperfícieRESUMO
BACKGROUND AND PURPOSE: Energy metabolism is altered in patients with amyotrophic lateral sclerosis (ALS) but the role of diabetes is largely unknown. METHODS: A population-based case-control study was conducted of 5108 ALS cases and 25,540 individually matched population controls during 1991-2010. Information on ALS and pre-existing diabetes was retrieved from the Swedish Patient Register to explore the association of ALS with diabetes overall and with insulin-dependent or non-insulin-dependent diabetes specifically. Variation of the association by diabetes duration and age was also studied. RESULTS: In total, 224 ALS cases (4.39%) and 1437 controls (5.63%) had diabetes before the index date, leading to an overall inverse association between diabetes and ALS risk [odds ratio (OR) 0.79, 95% confidence interval (CI) 0.68-0.91]. The association was strong for non-insulin-dependent diabetes (OR 0.66, 95% CI 0.53-0.81) but not for insulin-dependent diabetes (OR 0.83, 95% CI 0.60-1.15) and varied as a function of diabetes duration, with the strongest association observed around 6 years after first ascertainment of diabetes. The association was age-specific; the inverse association was noted only amongst individuals aged 70 or older. In contrast, for younger individuals (<50 years), pre-existing insulin-dependent diabetes was associated with a higher ALS risk (OR 5.38, 95% CI 1.87-15.51). CONCLUSIONS: Our study suggests that there is an association between diabetes and ALS, and highlights the importance of taking into account age, insulin dependence and diabetes duration. Future studies should explore whether the association is independent of body mass index.
Assuntos
Esclerose Lateral Amiotrófica/epidemiologia , Diabetes Mellitus Tipo 1/epidemiologia , Diabetes Mellitus Tipo 2/epidemiologia , Sistema de Registros , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Comorbidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Suécia/epidemiologiaRESUMO
Prospective cohorts have played a major role in understanding the contribution of diet, physical activity, medical conditions, and genes to the development of many diseases, but have not been widely used for occupational exposures. Studies in agriculture are an exception. We draw upon our experience using this design to study agricultural workers to identify conditions that might foster use of prospective cohorts to study other occupational settings. Prospective cohort studies are perceived by many as the strongest epidemiologic design. It allows updating of information on exposure and other factors, collection of biologic samples before disease diagnosis for biomarker studies, assessment of effect modification by genes, lifestyle, and other occupational exposures, and evaluation of a wide range of health outcomes. Increased use of prospective cohorts would be beneficial in identifying hazardous exposures in the workplace. Occupational epidemiologists should seek opportunities to initiate prospective cohorts to investigate high priority, occupational exposures.
Assuntos
Exposição Ocupacional/análise , Medicina do Trabalho , Estudos Prospectivos , Doenças dos Trabalhadores Agrícolas/etiologia , Projetos de Pesquisa Epidemiológica , HumanosRESUMO
Fusobacterium nucleatum is considered one of the main risk factors that play a key role in the promotion and progression of colorectal carcinoma. The main goal of this study is to find out the association between the prevalence of various subtypes of Fusobacterium nucleatum with inflammation and colorectal cancer progression, in addition to screening the positive ratio of the possession of the FadA gene. One hundred tissue samples were collected from healthy individuals and patients from colonoscopy and surgical operation biopsies. The patients were categorized into (Ulcerative colitis, precancerous colitis and colorectal carcinoma) according to their colonoscopy and histopathology examination reports. Molecular detection of Fusobacterium nucleatum and FadA gene was performed via PCR and gel electrophoresis, and then phylogenetic analysis for Fusobacterium nucleatum was done using 16S rRNA partial sequencing based on specific primers. The results showed significant differences among the four groups regarding the prevalence of Fusobacterium nucleatum. The most prevalent subtype was Fusobacterium nucleatum subtype animalis, which constitutes 7 out of 17 samples. The ratio of the FadA-positive gene was 20% among the Fusobacterium nucleatum-positive cases. This finding suggested a strong correlation between Fusobacterium nucleatum and colon inflammation and cancer progression steps, and Fusobacterium nucleatum subtype animalis was the most prevalent subtype.
Assuntos
Colite Ulcerativa , Neoplasias Colorretais , Lesões Pré-Cancerosas , Humanos , Neoplasias Colorretais/epidemiologia , Fusobacterium nucleatum , Inflamação , Iraque , Filogenia , Prevalência , RNA Ribossômico 16S , Fatores de VirulênciaRESUMO
OBJECTIVE: The long-term consequences of congenital diaphragmatic hernia (CDH), which include altered lung functions and compromised cardiopulmonary capacity, impact functional performance and quality of life. This study investigates the effects of virtual reality-based exercise programs on pulmonary functions, cardiopulmonary capacity, functional performance, and quality of life in children with repaired CDH. PATIENTS AND METHODS: A randomized controlled clinical trial was performed. Fifty-two children with repaired CDH (aged 6-10 years) were enrolled and randomly allocated to virtual reality-based exercises plus traditional physical therapy (VR-EX group, n = 26) or traditional physical therapy alone (control group, n = 26). Interventions were conducted three times a week for 12 weeks. Pulmonary functions, cardiopulmonary capacity, functional performance, and quality of life were assessed before and after the intervention. RESULTS: The VR-EX group demonstrated significantly enhanced post-treatment pulmonary functions and cardiopulmonary capacity compared to the control group after accounting for the pre-treatment values (p < 0.05). In addition, the values in functional performance and quality of life measures showed significantly larger improvements in the VR-EX group (p < 0.05). CONCLUSIONS: Children with repaired CDH may benefit more from VR-based exercises when combined with traditional physical therapy than from traditional physical therapy alone regarding their pulmonary functions, cardiopulmonary capacity, functional performance, and quality of life.
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OBJECTIVE: To explore the impact of vitamin D deficiency (VD-) in the pathogenesis of metabolic syndrome (MetS). MATERIALS AND METHODS: Models of (VD-) and (MetS) were induced in male Wister rats by dividing into four groups, group-I for the development of (VD-) by intraperitoneal injection of paricalcitol for 3 weeks, group II for (MetS) model by adding 10% fructose to their drinking water for 8 weeks, the group III for induction of combined (VD- + MetS) and group-IV as a control. Ultimately, the parameters of (VD-) and (MetS) were assessed at zero time and after 8 weeks. RESULTS: Both (VD-) and (MetS) groups alone displayed a remarkable enhancement of blood pressure, glucose and insulin levels, triglycerides, cholesterol, and low-density lipoproteins with a reduction of high-density lipoproteins. Additionally, all distinguishing features of obesity were substantially increased. Nevertheless, the combined group (VD-+MetS) demonstrated an expeditious and substantial increase in all the aforesaid parameters compared to the (VD-) and (MetS) groups alone. CONCLUSIONS: The hallmark of this study, reinforces a new frontier of awareness of the deleterious effect of (VD-) on each component of (MetS). Eventually, supplementation of vitamin D can circumvent the elements of (MetS) and needs further validation by determination of (VD-) molecular pathway on the parameters of (MetS).
Assuntos
Síndrome Metabólica , Deficiência de Vitamina D , Masculino , Ratos , Animais , Ratos Wistar , Deficiência de Vitamina D/complicações , Vitamina D , VitaminasRESUMO
OBJECTIVE: The aim of the study was to investigate the effect of a 3-month, trampoline-based stretch-shortening cycle (SSC) exercises on muscle strength and postural control in children with Down's syndrome (DS). PATIENTS AND METHODS: Thirty-two children with DS aged between 7-9 years were enrolled and randomly assigned into the control group (n = 16); received standard physical therapy (sPT) or SSC group (n = 16); received sPT in addition to a 15-minute, trampoline-based SSC training program twice per week for 12 successive weeks. Lower limb muscle strength and postural stability [anterior/posterior stability index (A/P-SI), medial/lateral stability index (M/L-SI)], and overall stability index (O-SI) were assessed pre- and post-treatment. RESULTS: Strength of hip extensor (p=0.034) and adductor (p=0.015), knee extensor (p=0.028) and flexor (p=0.01), and ankle dorsi (p=0.033) and plantar flexor (p=0.007) muscles increased significantly in the SSC group when compared with the control group. Also, the A/P-SI (p=0.019), M/L-SI (p=0.002), and O-SI (p=0.021) decreased significantly in the SSC group when compared with the control group, suggesting better postural control. CONCLUSIONS: Twelve weeks of trampoline-based SSC exercises are likely effective for enhancing muscle strength and postural control in children with DS and should consequently be included in the rehabilitation programs for these children.
Assuntos
Síndrome de Down , Exercício Pliométrico , Criança , Terapia por Exercício , Humanos , Força Muscular/fisiologia , Equilíbrio Postural/fisiologiaRESUMO
BACKGROUND AND PURPOSE: In 1-methyl-4-phenyl 1,2,3,6-tetrahydropyridine animal models of Parkinson's disease (PD), caffeine protects neurons by blocking the adenosine receptor A2A (ADORA2A). Caffeine is primarily metabolized by cytochrome P450 1A2 (CYP1A2). Our objective was to examine whether ADORA2A and CYP1A2 polymorphisms are associated with PD risk or modify the caffeine-PD association. METHODS: Parkinson's Epidemiology and Genetic Associations Studies in the United States (PEGASUS) included five population-based case-control studies. One laboratory genotyped four ADORA2A and three CYP1A2 polymorphisms in 1325 PD cases and 1735 age- and sex-matched controls. Information regarding caffeine (coffee) consumption and other lifestyle factors came from structured in-person or telephone interviews. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression. RESULTS: Two ADORA2A polymorphisms were inversely associated with PD risk - rs71651683, a 5' variant (adjusted allelic OR = 0.51, 95% CI 0.33-0.80, permutation-adjusted P = 0.015) and rs5996696, a promoter region variant (adjusted OR for AC and CC genotypes compared with the AA wild-type genotype were 0.76 (95% CI 0.57-1.02) and 0.37 (95% CI 0.13-1.01), respectively (permutation-adjusted P for trend = 0.04). CYP1A2 polymorphisms were not associated with PD risk; however, the coffee-PD association was strongest among subjects homozygous for either variant allele rs762551 (P(interaction) = 0.05) or rs2470890 (P(interaction) = 0.04). CONCLUSION: In this consortium study, two ADORA2A polymorphisms were inversely associated with PD risk, but there was weak evidence of interaction with coffee consumption. In contrast, the coffee-PD association was strongest among slow metabolizers of caffeine who were homozygous carriers of the CYP1A2 polymorphisms.
Assuntos
Cafeína/metabolismo , Citocromo P-450 CYP1A2/genética , Predisposição Genética para Doença/genética , Fármacos Neuroprotetores/farmacologia , Doença de Parkinson/genética , Receptor A2A de Adenosina/genética , Idoso , Cafeína/uso terapêutico , Estudos de Casos e Controles , Estudos de Coortes , Feminino , Predisposição Genética para Doença/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Fármacos Neuroprotetores/metabolismo , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/epidemiologia , Inibidores de Fosfodiesterase/metabolismo , Inibidores de Fosfodiesterase/uso terapêuticoRESUMO
Exposure to certain environmental toxicants may be associated with increased risk of developing diabetes. The authors' aim was to investigate the relation between lifetime exposure to specific agricultural pesticides and diabetes incidence among pesticide applicators. The study included 33,457 licensed applicators, predominantly non-Hispanic White males, enrolled in the Agricultural Health Study. Incident diabetes was self-reported in a 5-year follow-up interview (1999-2003), giving 1,176 diabetics and 30,611 nondiabetics for analysis. Lifetime exposure to pesticides and covariate information were reported by participants at enrollment (1993-1997). Using logistic regression, the authors considered two primary measures of pesticide exposure: ever use and cumulative lifetime days of use. They found seven specific pesticides (aldrin, chlordane, heptachlor, dichlorvos, trichlorfon, alachlor, and cyanazine) for which the odds of diabetes incidence increased with both ever use and cumulative days of use. Applicators who had used the organochlorine insecticides aldrin, chlordane, and heptachlor more than 100 lifetime days had 51%, 63%, and 94% increased odds of diabetes, respectively. The observed association of organochlorine and organophosphate insecticides with diabetes is consistent with results from previous human and animal studies. Long-term exposure from handling certain pesticides, in particular, organochlorine and organophosphate insecticides, may be associated with increased risk of diabetes.
Assuntos
Doenças dos Trabalhadores Agrícolas/induzido quimicamente , Agroquímicos/efeitos adversos , Diabetes Mellitus Tipo 2/induzido quimicamente , Praguicidas/efeitos adversos , Idoso , Agroquímicos/análise , Diabetes Mellitus Tipo 2/epidemiologia , Feminino , Seguimentos , Humanos , Hidrocarbonetos Clorados/efeitos adversos , Incidência , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Exposição Ocupacional , Organofosfatos/efeitos adversos , Resíduos de Praguicidas/efeitos adversos , Resíduos de Praguicidas/análise , Fatores de Risco , Inquéritos e QuestionáriosRESUMO
Exposure to high levels of many pesticides has both acute and long-term neurologic consequences, but little is known about the neurotoxicity of chronic exposure to moderate pesticide levels. We analysed cross-sectional data from 18 782 Caucasian, male, licensed pesticide applicators, enrolled in the Agricultural Health Study from 1993 to 1997. Applicators provided information on lifetime pesticide use, and 23 neurologic symptoms typically associated with pesticide intoxication. Increased risk of experiencing >/=10 symptoms during the year before enrollment was associated with cumulative pesticide use, personally mixing or applying pesticides, pesticide-related medical care, diagnosed pesticide poisoning, and events involving high personal pesticide exposure. Greatest risk was associated with use of organophosphate and organochlorine insecticides. Results were similar after stratification by pesticide use during the year before enrollment, or exclusion of applicators with a history of pesticide poisoning, or high-exposure events. Use of pesticide application methods likely to involve high personal exposure was associated with greater risk. Groups of symptoms reflecting several neurologic domains, including affect, cognition, autonomic and motor function, and vision, were also associated with pesticide exposure. These results suggest that neurologic symptoms are associated with cumulative exposure to moderate levels of organophosphate and organochlorine insecticides, regardless of recent exposure or history of poisoning.
Assuntos
Hidrocarbonetos Clorados/toxicidade , Doenças do Sistema Nervoso/induzido quimicamente , Exposição Ocupacional/efeitos adversos , Compostos Organofosforados/toxicidade , Praguicidas/toxicidade , Adolescente , Adulto , Idoso , Agricultura , Estudos de Casos e Controles , Estudos de Coortes , Humanos , Iowa/epidemiologia , Masculino , Pessoa de Meia-Idade , Doenças do Sistema Nervoso/epidemiologia , North Carolina/epidemiologiaRESUMO
AIM: The aim was to examine the anti-proliferative effect of a Withania somnifera (WS) root extract in cell cultures and nude mouse xenografts of breast cancer cell line MDA-MB-231. METHODS: WS root extract was used to treat tumor cells at concentrations up to 100 µg and for nude mouse experiments, the mice received daily WS at 300 mg/kg by oral gavage for 8 weeks. RESULTS: The WS extract reduced viability of MDA-MB-231 cells by 75% and 88% after exposure of the cells to 50 and 100 µg/mL, respectively, compared to vehicle-treated controls. WS extract caused a dose-dependent increase in the percentage of cells in the sub-G1 phase compared to untreated controls by 6% and 10% after exposure to 25 and 50 µg/mL WS extract, respectively. WS extract also inhibited proliferation of xenografted MDA-MB-231 cells. The WS extract caused reductions in xenograft size by 60% compared to the untreated control after 8 weeks of treatment. Six of ten mice in the control group showed tumor metastasis to the lung, whereas there was none in the mice treated with the WS extract. At the gene level, WS caused a 75% reduction in chemokine CCL2 expression (P < 0.05) in the xenografted tumors of the treated mice. CONCLUSION: WS root extract inhibited proliferation of breast cancer cells in vitro and in vivo and significantly reduced expression of the cytokine, CCL2. These results warrant further studies to assess the underlying molecular mechanism of the anti-tumor activity of the WS extract in breast cancer.
RESUMO
The effects of corticosterone (B) on pituitary responsiveness to LHRH and on gonadal steroid modulation of gonadotropin secretion were investigated using primary cultures of rat pituitary cells. Cultures were treated for 2 days with steroids and then challenged with LHRH for 4 h. B inhibited LH secretion, increasing the EC50 for LHRH from 1.40 to 4.96 nM. The reduction in LH release was accompanied by an increase in cell LH, so that the total amount of LH present in the cultures was unchanged. The EC50 for the effect of B on LH secretion was 0.57 microM. B increased the total amount of FSH present in the cultures. At high concentrations of B (10-100 microM), this effect was associated with an increase in FSH secretion. Testosterone inhibited LH secretion in both the absence and the presence of B. B had no effect in the presence of maximal concentrations of testosterone but augmented the inhibitory effect of lower concentrations. Estradiol (E) stimulated LH secretion in both the absence and the presence of B. However, the stimulatory effect of E was reduced by B, so that cultures treated with both B and E secreted no more LH than untreated cultures. B inhibited the LH secretory responses to Ca2+ influx and protein kinase C activation but did not affect the response to arachidonic acid, suggesting that the mechanism of B action may involve an inhibition of arachidonic acid release. Together these results indicate that the inhibitory effects of stress on reproduction are mediated at least partially by the inhibitory effects of B on LH secretion.
Assuntos
Corticosterona/farmacologia , Hormônio Foliculoestimulante/metabolismo , Hormônios Esteroides Gonadais/farmacologia , Hormônio Luteinizante/metabolismo , Adeno-Hipófise/metabolismo , Animais , Células Cultivadas , Interações Medicamentosas , Estradiol/farmacologia , Feminino , Hormônio Liberador de Gonadotropina/farmacologia , Adeno-Hipófise/efeitos dos fármacos , Ratos , Ratos Endogâmicos , Testosterona/farmacologiaRESUMO
Recent studies have shown that LH secretion in vivo is pulsatile. In the present study, a cell perifusion system was employed to characterize the pituitary response to changes in LHRH pulse amplitude and frequency. Increases in pulse amplitude consistently elevated both mean LH levels and the amount of LH released in response to individual LHRH pulses. The EC50 for LHRH was approximately 3 nM. Increases in pulse frequency also increased mean LH levels, but frequencies of three or more pulses per h were associated with a decrease in the amount of LH released per pulse. Alterations in LHRH pulse characteristics changed qualitative as well as quantitative aspects of LH secretion, with high frequency, high amplitude pulses producing a biphasic response to LHRH. Initially a self-priming response was seen during the second and third hours of stimulation; this was followed by increasing desensitization of the cultures to LHRH. These results, by defining the pituitary response to specific conditions of stimulation, will help to clarify the relationship of LHRH stimulation to LH secretion in vivo.
Assuntos
Hormônio Liberador de Gonadotropina/farmacologia , Hormônio Luteinizante/metabolismo , Adeno-Hipófise/metabolismo , Animais , Células Cultivadas , Feminino , Hormônio Liberador de Gonadotropina/administração & dosagem , Perfusão , Periodicidade , Adeno-Hipófise/efeitos dos fármacos , Ratos , Ratos EndogâmicosRESUMO
Recent studies have shown that LH secretion is pulsatile and that LH pulse characteristics are affected by the prevailing steroid environment in both male and female rats. In the present study, a cell perifusion system was used to examine the effects of testosterone (T) and 17 beta-estradiol (E) on LHRH-stimulated pulsatile LH secretion. T inhibited LH secretion, increasing the EC50 for LHRH, while E stimulated secretion, lowering the EC50. Steroid effects were independent of both LHRH pulse amplitude and frequency. E also affected the pattern of LH secretion by facilitating both LHRH self-priming and desensitization to LHRH. These results show that steroids can affect pulsatile LH secretion by actions exerted at the pituitary level and that steroids can induce both quantitative and qualitative changes in LH secretion in the presence of an invariant LHRH stimulus. These results help to elucidate the mechanisms underlying steroid feedback in vivo, since reduction in pituitary responsiveness to LHRH may play an important role in T feedback, while facilitation by E of both self-priming and desensitization may serve to increase the magnitude and shorten the duration of the proestrous LH surge.
Assuntos
Estradiol/farmacologia , Hormônio Luteinizante/metabolismo , Adeno-Hipófise/metabolismo , Testosterona/farmacologia , Animais , Células Cultivadas , Relação Dose-Resposta a Droga , Interações Medicamentosas , Retroalimentação , Feminino , Hormônio Liberador de Gonadotropina/administração & dosagem , Hormônio Liberador de Gonadotropina/farmacologia , Perfusão , Periodicidade , Adeno-Hipófise/efeitos dos fármacos , Ratos , Ratos EndogâmicosRESUMO
To investigate the mechanisms by which GnRH regulates LH production during intrauterine life, dispersed pituitary cells from second trimester human fetuses were cultured on extracellular matrix-coated plates for 48 h. Exposure of cells to 3 x 10(-10) mol/L GnRH for 1-48 h significantly increased cumulative LH secretion compared to that in respective controls (P less than 0.01). The rate of GnRH-stimulated LH release was accelerated during the first 6 h, after which it declined to a level similar to that of basal release. This phenomenon was associated with a decrease in the GnRH concentration of the medium. Exposure of cells to GnRH (3 x 10(-10) to 10(-6) mol/L) for 48 h induced a dose-dependent elevation of total LH which correlated with an increase in releasable, but not cellular, LH. Desensitization to GnRH (10(-7) mol/L) occurred when cells were cultured with pharmacological amounts of GnRH for 48 h. These results indicate that GnRH induces the increase in total and releasable LH in human fetal pituitary cells. These cells also appear to inactivate GnRH. Thus, GnRH may increase LH production in the human fetal pituitary and the pituitary receptor mechanism may be involved in GnRH action on LH release during intrauterine life.
Assuntos
Hormônio Liberador de Gonadotropina/farmacologia , Hormônio Luteinizante/análise , Hipófise/metabolismo , Células Cultivadas , Meios de Cultura/análise , Relação Dose-Resposta a Droga , Feminino , Idade Gestacional , Hormônio Liberador de Gonadotropina/análise , Humanos , Hormônio Luteinizante/biossíntese , Masculino , Hipófise/efeitos dos fármacos , Hipófise/embriologia , Radioimunoensaio , Fatores de TempoRESUMO
We explored the association between immune-related conditions and adult acute leukemia in a study of 624 patients with acute myeloid leukemia (AML), 124 patients with acute lymphoblastic leukemia (ALL), 63 patients with other acute leukemias, and 637 healthy population controls. Common childhood viral diseases were weakly associated with AML and ALL, particularly with early exposure (< or = 5 years of age). Odds ratios (ORs) were elevated for chicken pox and measles at any age, but only the associations with measles were statistically significant [OR = 1.89; 95% confidence interval (CI), 1.40-2.56 for AML and OR = 1.81; 95% CI, 1.07-3.06 for ALL]. There was no association between other infectious diseases, allergies, asthma, or eczema and risk for AML or ALL, although there was a significant association between psoriasis and ALL (OR = 3.23; 95% CI, 1.25-8.30). These results offer little support for either a protective effect of enhanced immune surveillance or a harmful effect from antigenic stimulation in relation to risk for acute leukemia in adults. However, the associations between cancer risk and childhood infectious diseases are intriguing and may warrant additional research.
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Doenças Transmissíveis/imunologia , Leucemia/epidemiologia , Doença Aguda , Adulto , Idoso , Doenças Autoimunes/imunologia , Estudos de Casos e Controles , Causalidade , Varicela/imunologia , Feminino , Humanos , Hipersensibilidade/imunologia , Leucemia/imunologia , Leucemia Mieloide/epidemiologia , Leucemia Mieloide/imunologia , Masculino , Sarampo/imunologia , Pessoa de Meia-Idade , Leucemia-Linfoma Linfoblástico de Células Precursoras/epidemiologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/imunologia , Psoríase/imunologia , Fatores de RiscoRESUMO
Primary cultures of enzymatically dispersed rat pituitary cells were used to examine steroid effects on LH secretion stimulated by LHRH, Ca2+ and cAMP. Cultures were pretreated for 48 h with testosterone (T) or 17 beta-estradiol (E) and then challenged for 4 h with various secretogogues. T did not affect basal LH secretion; it inhibited the responses to Ca2+ and LHRH; and it potentiated the response to cAMP. E stimulated both basal LH secretion and the responses to all secretogogues, without affecting cell LH content. Thus, T affects stimulus-secretion coupling, while E affects secretion per se. All steroid effects were blocked by steroid antagonists, indicating that steroid action is receptor-mediated regardless of the secretogogue involved. The similarity of steroid effects on the responses to LHRH and Ca2+ but not cAMP suggests that Ca2+ rather than cAMP is a second messenger for LHRH, and that steroid action occurs at some step subsequent to LHRH-stimulated Ca2+ mobilization.
Assuntos
Cálcio/farmacologia , AMP Cíclico/farmacologia , Hormônios Esteroides Gonadais/farmacologia , Hormônio Liberador de Gonadotropina/farmacologia , Hormônio Luteinizante/metabolismo , Animais , Calcimicina/farmacologia , Contagem de Células , Toxina da Cólera/farmacologia , Ciproterona/farmacologia , Feminino , Nitromifeno/farmacologia , Potássio/farmacologia , Ratos , Receptores de Superfície Celular/efeitos dos fármacos , Receptores LHRHRESUMO
Enzymatically dispersed rat pituitary cells were grown in primary culture, and LHRH-stimulated LH secretion was measured. Testosterone (T) decreased and 17 beta-estradiol (E) increased pituitary responsiveness to LHRH. The effect of E on LH secretion was partly due to an increase in LH content. There was a latent period of 12 h for E and 18 h for T between the onset of steroid treatment and the manifestation of steroid action. Neither steroid was required to be continuously present in order to exert its effects. After steroid withdrawal, the effect of T persisted for 72 h and that of E for more than 96 h. The actions of both steroids were blocked by protein-synthesis inhibitors. These results are consistent with the hypothesis that steroid effects rely on a mechanism involving alterations in protein synthesis; the affected proteins may be involved in the process of LHRH action.