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1.
Vaccines (Basel) ; 12(6)2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38932366

RESUMO

Although vaccines address critical public health needs, inter-individual differences in responses are not always considered in their development. Understanding the underlying basis for these differences is needed to optimize vaccine effectiveness and ultimately improve disease control. In this pilot study, pre- and post-antiviral immunological and gut microbiota features were characterized to examine inter-individual differences in SARS-CoV-2 mRNA vaccine response. Blood and stool samples were collected before administration of the vaccine and at 2-to-4-week intervals after the first dose. A cohort of 14 adults was separated post hoc into two groups based on neutralizing antibody levels (high [HN] or low [LN]) at 10 weeks following vaccination. Bivariate correlation analysis was performed to examine associations between gut microbiota, inflammation, and neutralization capacity at that timepoint. These analyses revealed significant differences in gut microbiome composition and inflammation states pre-vaccination, which predicted later viral neutralization capacity, with certain bacterial taxa, such as those in the genus Prevotella, found at higher abundance in the LN vs HN group that were also negatively correlated with a panel of inflammatory factors such as IL-17, yet positively correlated with plasma levels of the high mobility group box 1 (HMGB-1) protein at pre-vaccination. In particular, we observed a significant inverse relationship (Pearson = -0.54, p = 0.03) between HMGB-1 pre-vaccination and neutralization capacity at 10 weeks post-vaccination. Consistent with known roles as mediators of inflammation, our results altogether implicate HMGB-1 and related gut microbial signatures as potential biomarkers in predicting SARS-CoV-2 mRNA vaccine effectiveness measured by the production of viral neutralization antibodies.

2.
Nutrients ; 16(10)2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38794639

RESUMO

In this interventional pilot study, we investigated the effects of a modified ketogenic diet (KD) on children with autism spectrum disorder (ASD). We previously observed improved behavioral symptoms in this cohort following the KD; this trial was registered with Clinicaltrials.gov (NCT02477904). This report details the alterations observed in the microbiota, inflammation markers, and microRNAs of seven children following a KD for a duration of 4 months. Our analysis included blood and stool samples, collected before and after the KD. After 4 months follow up, we found that the KD led to decreased plasma levels of proinflammatory cytokines (IL-12p70 and IL-1b) and brain-derived neurotrophic factor (BDNF). Additionally, we observed changes in the gut microbiome, increased expression of butyrate kinase in the gut, and altered levels of BDNF-associated miRNAs in the plasma. These cohort findings suggest that the KD may positively influence ASD sociability, as previously observed, by reducing inflammation, reversing gut microbial dysbiosis, and impacting the BDNF pathway related to brain activity.


Assuntos
Transtorno do Espectro Autista , Fator Neurotrófico Derivado do Encéfalo , Citocinas , Dieta Cetogênica , Microbioma Gastrointestinal , MicroRNAs , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Transtorno do Espectro Autista/microbiologia , Transtorno do Espectro Autista/dietoterapia , Encéfalo/metabolismo , Fator Neurotrófico Derivado do Encéfalo/sangue , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Fator Neurotrófico Derivado do Encéfalo/genética , Citocinas/sangue , Disbiose , Inflamação , MicroRNAs/sangue , MicroRNAs/metabolismo , Projetos Piloto
4.
Sci Rep ; 14(1): 355, 2024 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-38172612

RESUMO

While obesity is a risk factor for post-acute sequelae of SARS-CoV-2 infection (PASC, "long-COVID"), the mechanism(s) underlying this phenomenon remains poorly understood. To address this gap in knowledge, we performed a 6-week longitudinal study to examine immune activity and gut microbiome dysbiosis in post-acute stage patients recovering from SARS-CoV-2 infection. Self-reported symptom frequencies and blood samples were collected weekly, with plasma assessed by ELISA and Luminex for multiple biomarkers and immune cell profiling. DNA from stool samples were collected at the early stage of recovery for baseline assessments of gut microbial composition and diversity using 16S-based metagenomic sequencing. Multiple regression analyses revealed obesity-related PASC linked to a sustained proinflammatory immune profile and reduced adaptive immunity, corresponding with reduced gut microbial diversity. In particular, enhanced signaling of the high mobility group box 1 (HMGB1) protein was found to associate with this dysregulation, with its upregulated levels in plasma associated with significantly impaired viral neutralization that was exacerbated with obesity. These findings implicate HMGB1 as a candidate biomarker of PASC, with potential applications for risk assessment and targeted therapies.


Assuntos
COVID-19 , Proteína HMGB1 , Microbiota , Humanos , COVID-19/complicações , Progressão da Doença , Proteína HMGB1/genética , Estudos Longitudinais , Obesidade/complicações , Síndrome de COVID-19 Pós-Aguda , SARS-CoV-2
5.
Eur J Biomed Res ; 2(3): 17-23, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37525697

RESUMO

Whole-genome SARS-CoV-2 sequencing tools are crucial for tracking the COVID-19 pandemic. However, current techniques require sampling of actively infectious patients following COVID-19 testing to recover enough SARS-CoV-2 RNA from the nasopharyngeal passage, which rapidly clears during the first few weeks of infection. A prospective assessment of the viral genome sourced from recovered non-infectious patients would greatly facilitate epidemiological tracking. Thus, we developed a protocol to isolate and sequence the genome of SARS-CoV-2 from stool samples of post-acute SARS-CoV-2 patients, at timepoints ranging from 10-120 days after onset of symptoms. Stool samples were collected from patients at varying timepoints post-convalescence, and viral DNA was isolated and sequenced using the QIAamp Viral RNA Mini Kit (Qiagen Inc.) and Ion Ampliseq™ Library Kit Plus (Life Technologies Corporation). Capacity of neutralizing antibodies in patient plasma was tested using a Luminex panel (Coronavirus Ig Total Human 11-Plex ProcartaPlex™ Panel, ThermoFisher). Of 64 samples obtained from post-acute patients, 21 (32.8%) yielded sufficient material for whole-genome sequencing. This allowed us to identify widely divergent phylogenetic relativity of the SARS-CoV-2 genome from post-acute patients living in the same households and infected around the same time. Additionally, we observed that individuals who recovered from infection expressed varying degrees of antibodies against SARS-CoV-2 structural proteins that corresponded to distinct variants. Interestingly, we identified a novel point mutation in the viral genome where infected patients expressed antibodies with a significantly reduced capacity to neutralize the virus in vitro relative to that of those infected with the wild-type strain. Altogether, we demonstrate a protocol to successfully sequence the SARS-CoV-2 genome from stool samples from patients up to 4 months post-infection, which can be applied to studies that assess the relationship between variants and immune response post-hoc and safe monitoring of the SARS-CoV-2 genome during the pandemic.

6.
Front Genet ; 14: 1125217, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37152987

RESUMO

Introduction: Native Hawaiian and other Pacific Islander (NHPI) populations experience higher rates of immunometabolic diseases compared to other racial-ethnic groups in Hawaii. As annual NHPI mortality rates for suicide and type 2 diabetes mellitus (T2DM) exceed those of the state as a whole, understanding the social and biological mechanisms underlying these disparities are urgently needed to enable preventive strategies. Methods: A community-based approach was used to investigate the immunoepigenetic-gut microbiome axis in an NHPI-enriched cohort of Oahu residents (N = 68). Self-esteem (SE) data was collected using a modified Rosenberg self-esteem (SE) assessment as a proxy measure for mental wellbeing in consideration for cultural competency. T2DM status was evaluated using point-of-care A1c (%) tests. Stool samples were collected for 16s-based metagenomic sequencing analyses. Plasma from blood samples were isolated by density-gradient centrifugation. Peripheral blood mononuclear cells (PBMCs) were collected from the same samples and enriched for monocytes using negative selection techniques. Flow-cytometry was used for immunoprofiling assays. Monocyte DNA was extracted for Illumina EPIC array-based methylation analysis. Results: Compared to individuals with normal SE (NSE), those with low SE (LSE) exhibited significantly higher plasma concentrations (pg/ml) of proinflammatory cytokines IL-8 (p = 0.051) and TNF-α (p = 0.011). Metagenomic analysis revealed that the relative abundance (%) of specific gut bacteria significantly differed between SE groups - some of which directly correlated with SE scores. Gene ontology analysis revealed that 104 significantly differentially methylated loci (DML) between SE groups were preferentially located at genes involved in immunometabolic processes. Horvath clock analyses indicated epigenetic age (Epi-Age) deceleration in individuals with LSE and acceleration in individuals with NSE (p = 0.042), yet was not reproduced by other clocks. Discussion: These data reveal novel differences in the immunoepigenetic-gut microbiome axis with respect to SE, warranting further investigation into its relationship to brain activity and mental health in NHPI. Unexpected results from Epi-Age analyses warrant further investigation into the relationship between biological age and disparate health outcomes among the NHPI population. The modifiable component of epigenetic processes and the gut microbiome makes this axis an attractive target for potential therapeutics, biomarker discovery, and novel prevention strategies.

7.
Front Cell Infect Microbiol ; 12: 1035641, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36619744

RESUMO

Native Hawaiians and Pacific Islanders (NHPIs) suffer from higher prevalence of and mortality to type 2 diabetes mellitus (T2DM) than any other major race/ethnic group in Hawaii. Health inequities in this indigenous population was further exacerbated by the SARS-CoV-2 pandemic. T2DM progression and medical complications exacerbated by COVID-19 are partially regulated by the gut microbiome. However, there is limited understanding of the role of gut bacteria in the context of inflammation-related diseases of health disparities including T2DM and obesity. To address these gaps, we used a community-based research approach from a cohort enriched with NHPI residents on the island of Oahu, Hawaii (N=138). Gut microbiome profiling was achieved via 16s rDNA metagenomic sequencing analysis from stool DNA. Gut bacterial capacity for butyrate-kinase (BUK)-mediated fiber metabolism was assessed using quantitative PCR to measure the abundance of BUK DNA and RNA relative to total bacterial load per stool sample. In our cohort, age positively correlated with hemoglobin A1c (%; R=0.39; P<0.001) and body mass index (BMI; R=0.28; P<0.001). The relative abundance of major gut bacterial phyla significantly varied across age groups, including Bacteroidetes (P<0.001), Actinobacteria (P=0.007), and Proteobacteria (P=0.008). A1c was negatively correlated with the relative levels of BUK DNA copy number (R=-0.17; P=0.071) and gene expression (R=-0.33; P=0.003). Interestingly, we identified specific genera of gut bacteria potentially mediating the effects of diet on metabolic health in this cohort. Additionally, α-diversity among gut bacterial genera significantly varied across T2DM and BMI categories. Together, these results provide insight into age-related differences in gut bacteria that may influence T2DM and obesity in NHPIs. Furthermore, we observed overlapping patterns between gut bacteria and T2DM risk factors, indicating more nuanced, interdependent interactions among these factors as partial determinants of health outcomes. This study adds to the paucity of NHPI-specific data to further elucidate the biological characteristics associated with pre-existing health inequities in this racial/ethnic group that is significantly underrepresented in biomedical research.


Assuntos
Diabetes Mellitus Tipo 2 , Microbioma Gastrointestinal , Obesidade , Humanos , Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Mellitus Tipo 2/microbiologia , Hemoglobinas Glicadas , Havaí/epidemiologia , Havaiano Nativo ou Outro Ilhéu do Pacífico , Obesidade/epidemiologia , Obesidade/microbiologia
8.
Clin Exp Allergy ; 50(3): 391-400, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31785105

RESUMO

BACKGROUND: The prevalence and severity of asthma, particularly the most common (atopic) form of the disease, increase amongst females but not males after puberty, and asthma activity also changes throughout the menstrual cycle and during pregnancy. The contribution of female sex hormones to asthma pathogenesis is incompletely understood. OBJECTIVE: To obtain insight into the role of oestrogen (E2) in experimental atopic asthma, and guide future research on sex-related variations in atopic asthma susceptibility/intensity in humans. METHODS: We utilized an experimental model comprising rat strains expressing dichotomous Th2-high vs Th2-low immunophenotypes exemplified by eosinophilia, mirroring differences between human atopics/non-atopics. We compared the efficiency of Th2-associated immunoinflammatory mechanisms, which differed markedly between the two strains, and between sexes in the Th2-high strain, and determined the effects of E2 administration on these differences. RESULTS: Unique to the Th2-high strain, eosinophil: neutrophil ratios in the airways at baseline and following sensitization/aeroallergen challenge were logfold higher in females relative to males, and this was reflected by higher baseline blood eosinophil numbers in females. Pretreatment of Th2-high males with E2 abrogated this sex difference by selectively boosting Th2-associated genes in the airways and eosinophilia, but was without corresponding effect in the Th2-low strain. In contrast, parallel E2 effects on myeloid and lymphoid cell populations were relatively modest. CONCLUSIONS AND CLINICAL RELEVANCE: E2 acts to amplify the eosinophilic component of pre-existing Th2-high immunophenotype, possibly acting at the level of the common eosinophil/neutrophil precursor in bone marrow to preferentially drive eosinophil differentiation. Constitutive granulocyte profiles in which the balance between eosinophils and neutrophils is skewed towards eosinophils have been identified in independent cohort studies as markers of asthma risk, and these findings suggest that more detailed studies on the role of E2 in this context, and in relation to asthma pathogenesis in post-pubertal females in particular, appear warranted.


Assuntos
Asma/imunologia , Estrogênios/farmacologia , Caracteres Sexuais , Células Th2/imunologia , Animais , Asma/tratamento farmacológico , Asma/patologia , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Ratos , Células Th2/patologia
9.
Bioconjug Chem ; 31(2): 214-223, 2020 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-31756298

RESUMO

New methods are described for the construction of targeted fluorescence probes for imaging cancer and the assessment of tumor targeting performance in a living mouse model. A novel noncovalent assembly process was used to fabricate a set of structurally related targeted fluorescent probes with modular differences in three critical assembly components: the emission wavelength of the squaraine fluorochrome, the number of cRGDfK peptide units that target the cancer cells, and the length of the polyethylene glycol chains as pharmacokinetic controllers. Selective targeting of cancer cells was proven by a series of cell microscopy experiments followed by in vivo imaging of subcutaneous tumors in living mice. The mouse imaging studies included a mock surgery that completely removed a fluorescently labeled tumor. Enhanced tumor accumulation due to probe targeting was first evaluated by conducting Single Agent Imaging (SAI) experiments that compared tumor imaging performance of a targeted probe and untargeted probe in separate mouse cohorts. Although there was imaging evidence for enhanced tumor accumulation of the targeted probe, there was moderate scatter in the data due to tumor-to-tumor variability of the vasculature structure and interstitial pressure. A subsequent Paired Agent Imaging (PAI) study coinjected a binary mixture of targeted probe (with emission at 690 nm) and untargeted probe (with emission at 830 nm) into the same tumor-burdened animal. The conclusion of the PAI experiment also indicated enhanced tumor accumulation of the targeted probe, but the statistical significance was much higher, even though the experiment required a much smaller cohort of mice. The imaging data from the PAI experiment was analyzed to determine the targeted probe's Binding Potential (BP) for available integrin receptors within the tumor tissue. In addition, pixelated maps of BP within each tumor indicated a heterogeneous spatial distribution of BP values. The results of this study show that the combination of fluorescent probe preassembly and PAI is a promising new way to rapidly develop targeted fluorescent probes for tumors with high BP and eventual use in clinical applications such as targeted therapy, image guided surgery, and personalized medicine.


Assuntos
Ciclobutanos/análise , Corantes Fluorescentes/análise , Neoplasias/diagnóstico por imagem , Imagem Óptica/métodos , Fenóis/análise , Células A549 , Animais , Feminino , Fluorescência , Humanos , Camundongos , Camundongos Nus , Sondas Moleculares/análise
10.
European J Org Chem ; 2019(21): 3489-3494, 2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-31579392

RESUMO

Croconaines are an emerging class of near-infrared dyes that are useful for various sensing, photothermal, optoelectronic, and photoacoustic applications. Previous work encapsulated a dumbbell-shaped croconaine dye whose structure contains two thiophene flanking units inside a tetralactam macrocycle and produced a croconaine rotaxane 1 with a narrow 824 nm absorption band. Herein, a new rotaxane 2 is reported that encapsulates a croconaine dye with two thienothiophene flanking units. The new croconaine rotaxane 2 exhibits a narrow 984 nm absorption band that is distinct from the 824 nm absorption of rotaxane 1. Photothermal heating experiments showed that an 830 nm diode laser selectively heats a solution containing rotaxane 1, with no heating of a solution containing rotaxane 2. Conversely, a 980 nm diode laser selectively heats a solution containing rotaxane 2, with no heating of a solution containing rotaxane 1. The new croconaine rotaxane 2 shows no fatigue after four cycles of laser heating and cooling.

12.
Arch Fam Med ; 9(8): 700-8, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10927707

RESUMO

BACKGROUND: Primary care treatment of depression needs improvement. OBJECTIVE: To evaluate the efficacy of 2 augmentations to antidepressant drug treatment. DESIGN: Randomized trial comparing usual care, telehealth care, and telehealth care plus peer support; assessments were conducted at baseline, 6 weeks, and 6 months. SETTING: Two managed care adult primary care clinics. PARTICIPANTS: A total of 302 patients starting antidepressant drug therapy. INTERVENTIONS: For telehealth care: emotional support and focused behavioral interventions in ten 6-minute calls during 4 months by primary care nurses; and for peer support: telephone and in-person supportive contacts by trained health plan members recovered from depression. MAIN OUTCOME MEASURES: For depression: the Hamilton Depression Rating Scale and the Beck Depression Inventory; and for mental and physical functioning: the SF-12 Mental and Physical Composite Scales and treatment satisfaction. RESULTS: Nurse-based telehealth patients with or without peer support more often experienced 50% improvement on the Hamilton Depression Rating Scale at 6 weeks (50% vs 37%; P =.01) and 6 months (57% vs 38%; P =.003) and on the Beck Depression Inventory at 6 months (48% vs 37%; P =. 05) and greater quantitative reduction in symptom scores on the Hamilton scale at 6 months (10.38 vs 8.12; P =.006). Telehealth care improved mental functioning at 6 weeks (47.07 vs 42.64; P =.004) and treatment satisfaction at 6 weeks (4.41 vs 4.17; P =.004) and 6 months (4.20 vs 3.94; P =.001). Adding peer support to telehealth care did not improve the primary outcomes. CONCLUSION: Nurse telehealth care improves clinical outcomes of antidepressant drug treatment and patient satisfaction and fits well within busy primary care settings.


Assuntos
Terapia Comportamental , Transtorno Depressivo/terapia , Programas de Assistência Gerenciada , Enfermeiras e Enfermeiros , Atenção Primária à Saúde , Consulta Remota , Apoio Social , Adulto , Idoso , Antidepressivos/uso terapêutico , California , Terapia Combinada , Transtorno Depressivo/tratamento farmacológico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , Satisfação do Paciente , Fatores de Tempo , Resultado do Tratamento
13.
Comp Biochem Physiol B ; 100(4): 759-62, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-1664307

RESUMO

1. Single 4th-instar larvae were used in the investigation of alkaline phosphohydrolase (APH) variability in Culex pipiens quinequefasciatus. The genetic basis of isozyme variability was determined from genetic crosses performed with isogenic and hybrid strains of mosquitoes. 2. Isozyme electromorphs presented four enzyme activity zones, three monomorphic and one polymorphic, correspondent with four APH gene loci (aph1, aph2, aph3 and aph4). 3. All isozymes migrated anodically, with aph4 isozymes migrating most rapidly. 4. Enzyme polymorphism was evident only at aph4 locus, with three allozymes present. 5. aph4 allozymes are conditioned by multiple, co-dominant alleles transmitted in a Mendelian manner. 6. Differential frequencies and selection for aph4 alleles and genotypes are suggested by data from genetic crosses.


Assuntos
Culex/genética , Isoenzimas/genética , Monoéster Fosfórico Hidrolases/genética , Animais , Cruzamentos Genéticos , Culex/enzimologia , Feminino , Isoenzimas/metabolismo , Masculino , Monoéster Fosfórico Hidrolases/metabolismo , Polimorfismo Genético
14.
Mutat Res ; 176(2): 269-74, 1987 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-3807937

RESUMO

When previously mated female mice were exposed to inhaled ethylene oxide at the time of fertilization of their eggs or during early pronuclear stage of the zygote (before DNA synthesis), a high incidence of mortality among conceptuses and of congenital abnormalities among both the dead and the surviving fetuses was observed. The developmental stage at which death occurred ranged from near the time of implantation to day 17 of gestation when examination of the uterine contents was performed. In comparison, midgestation and late fetal deaths were absent or minimal when the females were exposed either before mating or when conceptuses were in later zygotic stages (pronuclear DNA synthesis) or had reached the early two-cell stage. The random types of congenital abnormality observed and the remarkable stage-dependent sensitivity suggest a genetic basis for the response. The effects differ, both from genetic damages induced in premating germ cells, which lead only to death near the time of implantation, and from teratogenic damage, which leads to malformations only when exposure of embryos occurs during the period of major organogenesis.


Assuntos
Anormalidades Induzidas por Medicamentos/etiologia , Óxido de Etileno/toxicidade , Morte Fetal/induzido quimicamente , Zigoto/efeitos dos fármacos , Administração por Inalação , Animais , Desenvolvimento Embrionário e Fetal/efeitos dos fármacos , Óxido de Etileno/administração & dosagem , Feminino , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Oócitos/efeitos dos fármacos , Gravidez , Efeitos Tardios da Exposição Pré-Natal , Fatores de Tempo
15.
Mutat Res ; 163(3): 299-302, 1986 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-3785265

RESUMO

Unbalanced (duplication/deficiency) sperm from balanced reciprocal translocations induced in spermatogonial stem cells of mice generally lead to embryonic lethality around the time of implantation. In a recent study (Generoso et al., 1985), it was found that the incidence of X-ray-induced embryonic lethality differed markedly between two hybrid stocks of irradiated male mice. A parallel difference in the frequencies of reciprocal translocations was observed cytologically in the meiocytes of irradiated males. In the present report, which is an adjunct to the study by Generoso et al. (1985), it was determined whether or not similar differences between the two stocks exist for congenital defects resulting from genetic damage to stem-cell spermatogonia. The results indicate not only an association between the frequencies of induced reciprocal translocations and congenital abnormalities, but also a parallel greater frequency of induced malformations in the (C3H X 101)F1 stock versus the (SEC X C57BL)F1 stock of males.


Assuntos
Anormalidades Induzidas por Radiação/genética , Aberrações Cromossômicas/genética , Camundongos Endogâmicos C3H/genética , Camundongos Endogâmicos C57BL/genética , Espermatogônias/efeitos da radiação , Espermatozoides/efeitos da radiação , Animais , Aberrações Cromossômicas/etiologia , Transtornos Cromossômicos , Feminino , Morte Fetal/etiologia , Morte Fetal/genética , Masculino , Camundongos , Gravidez , Tolerância a Radiação , Translocação Genética , Raios X
16.
Environ Mutagen ; 8(1): 1-7, 1986.
Artigo em Inglês | MEDLINE | ID: mdl-3943495

RESUMO

In the dose-response study, male mice were exposed by inhalation to ethylene oxide (EtO) for 4 consecutive days. Mice were exposed for 6 hr per day to 300 ppm, 400 ppm, or 500 ppm EtO for a daily total of 1,800, 2,400, or 3,000 ppm X hr (total exposures of 7,200, 9,600 and 12,000 ppm X hr), respectively. In the dose-rate study, mice were given a total exposure of 1,800 ppm X hr per day, also for 4 consecutive days, delivered either at 300 ppm in 6 hr, 600 ppm in 3 hr, or 1,200 ppm in 1.5 hr. Quantitation of dominant-lethal responses was made on matings involving sperm exposed as late spermatids and early spermatozoa, the most sensitive stages to EtO. In the dose-response study, a dose-related increase in dominant-lethal mutations was observed, the dose-response curve proved to be nonlinear. In the dose-rate study, increasing the exposure concentrations resulted in increased dominant-lethal responses.


Assuntos
Óxido de Etileno/toxicidade , Genes Dominantes/efeitos dos fármacos , Genes Letais/efeitos dos fármacos , Mutagênicos , Poluentes Atmosféricos/toxicidade , Animais , Relação Dose-Resposta a Droga , Feminino , Masculino , Camundongos , Testes de Mutagenicidade , Gravidez
18.
Mutat Res ; 152(2-3): 217-23, 1985.
Artigo em Inglês | MEDLINE | ID: mdl-4069148

RESUMO

Ionizing radiation induces balanced reciprocal translocations in spermatogonial stem cells of mice. From cells carrying these rearrangements, which can be scored cytologically in the diakinesis-metaphase I stage, balanced normal, balanced translocated and unbalanced (duplication/deficiency) sperm can be produced. The relationship between expected (calculated from cytological data) and observed frequencies of embryonic lethality (presumably as a result of unbalanced sperm fertilizing the egg) following exposure of spermatogonial stem cells to X-rays was studied in two hybrid stocks. A marked difference in the incidence of induced embryonic lethality was found between the two stocks. Similarly, a difference in the cytological frequencies of translocations was also found, although smaller than that observed for embryonic lethality. Thus, it appears that the difference between the two stocks in the frequencies of embryonic lethality may be attributable both to processes occurring prior to metaphase I and to a difference in the rate of transmission of unbalanced chromosome constitutions.


Assuntos
Aberrações Cromossômicas , Espermatogônias/efeitos da radiação , Espermatozoides/efeitos da radiação , Animais , Biometria , Relação Dose-Resposta à Radiação , Implantação do Embrião , Feminino , Hibridização Genética , Tamanho da Ninhada de Vivíparos/efeitos da radiação , Masculino , Camundongos , Camundongos Endogâmicos , Modelos Biológicos , Gravidez , Especificidade da Espécie , Espermatogônias/citologia
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