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BACKGROUND: Almost two million stillbirths occur annually, most occurring in low- and middle-income countries. Nigeria is reported to have one of the highest stillbirth rates on the African continent. The aim was to identify sociodemographic, living environment, and health status factors associated with stillbirth and determine the associations between pregnancy and birth factors and stillbirth in the Murtala Mohammed Specialist Hospital, Kano, Nigeria. METHODS: A three-month single-site prospective observational feasibility study. Demographic and clinical data were collected. We fitted bivariable and multivariable models for stillbirth (yes/no) and three-category livebirth/macerated stillbirth/non-macerated stillbirth outcomes to explore their association with demographic and clinical factors. FINDINGS: 1,998 neonates and 1,926 mothers were enrolled. Higher odds of stillbirth were associated with low-levels of maternal education, a further distance to travel to the hospital, living in a shack, maternal hypertension, previous stillbirth, birthing complications, increased duration of labour, antepartum haemorrhage, prolonged or obstructed labour, vaginal breech delivery, emergency caesarean-section, and signs of trauma to the neonate following birth. INTERPRETATION: This work has obtained data on some factors influencing stillbirth. This in turn will facilitate the development of improved public health interventions to reduce preventable deaths and to progress maternal health within this site.
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Salud Materna , Mortinato , Femenino , Humanos , Incidencia , Recién Nacido , Nigeria/epidemiología , Embarazo , Mortinato/epidemiología , Atención Terciaria de SaludRESUMEN
OBJECTIVE: To explore the experiences and perceptions of stillbirth among mothers from a tertiary medical centre in Kano, Northern Nigeria. DESIGN: Qualitative, interpretative. SETTING: Tertiary healthcare facility, Murtala Muhammad Specialist Hospital (MMSH), Kano, Northern Nigeria. SAMPLE: Mothers who had given birth to a liveborn baby at the MMSH in the prior 6 months (n = 31). In order to capture the experiences and perception of stillbirth within this cohort we approached mothers who had in a previous pregnancy experienced a stillbirth. Of the 31 who attended 16 had a previous stillbirth. METHODS: Semi-structured Focus Group Discussions, consisting of open-ended questions about stillbirth, beliefs, experiences and influences were held in MMSH, conducted over 1 day. RESULTS: Our findings highlight that this is a resource-poor tertiary facility serving an ever-growing population, increasing strain on the hospital and healthcare workers. Many of the participants highlighted needing permission from certain family members before accessing healthcare or medical treatment. We identified that mothers generally have knowledge on self-care during pregnancy, yet certain societal factors prevented that from being their priority. Judgement and blame was a common theme, yet a complex area entwined with traditions, superstitions and the pressure to procreate with many mothers described being made to feel useless and worthless if they did not birth a live baby. CONCLUSIONS: As access to healthcare becomes easier, there are certain traditions, family and social dynamics and beliefs which conflict with scientific knowledge and act as a major barrier to uptake of healthcare services. The findings highlight the need for investment in maternity care, appropriate health education and public enlightenment; they will help inform appropriate interventions aimed at reducing stigma around stillbirth and aide in educating mothers about the importance of appropriate health seeking behaviour. Stillbirths are occurring in this area of the world unnecessarily, globally there has been extensive research conducted on stillbirth prevention. This research has highlighted some of the areas which can be tackled by modifying existing successful interventions to work towards reducing preventable stillbirths.
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Madres/psicología , Mortinato/psicología , Relaciones Familiares/etnología , Femenino , Grupos Focales , Accesibilidad a los Servicios de Salud , Humanos , Nigeria/etnología , Embarazo , Investigación Cualitativa , Valores Sociales/etnología , Vulnerabilidad SocialRESUMEN
BACKGROUND: Pregnancy in women with sickle-cell disease (SCD) is associated with increased adverse outcomes. Findings on the association between SCD and adverse pregnancy outcomes are conflicting, and the results do not address whether these associations are similar in both low- and high-income countries. OBJECTIVES: We conducted a systematic review and meta-analysis to evaluate pregnancy outcomes associated with SCD. SEARCH STRATEGY: The MEDLINE database was searched using medical subject headings (MeSH) and keywords for articles on pregnancy outcomes in women with SCD. SELECTION CRITERIA: We used full research articles published in English that compared women with SCD with women who did not have SCD, as controls. DATA COLLECTION AND ANALYSIS: Data were abstracted and analysed using comprehensive Meta-analysis 2.2. The primary outcomes were intrauterine growth restriction and perinatal mortality. Secondary outcomes were rates of caesarean sections, pre-eclampsia, eclampsia, postpartum haemorrhage, maternal mortality, prematurity, and low birthweight. Random-effects models were used to calculate pooled odds ratios (ORs) with 95% confidence intervals (95% CIs). MAIN RESULTS: Sixteen studies met all of the selection criteria and were included in the analysis. SCD was associated with intrauterine growth restriction (pooled OR 2.79, 95% CI 1.85-4.21), perinatal mortality (pooled OR 3.76, 95% CI 2.34-6.06), and low birthweight (pooled OR 2.00, 95% CI 1.42-2.83). SCD was also associated with an increased risk of pre-eclampsia (pooled OR 2.05, 95% CI 1.47-2.85), maternal mortality (pooled OR 10.91, 95% CI 1.83-65.11, P = 0.009), and eclampsia (pooled OR 3.02, 95% CI 1.20-7.58). CONCLUSION: Pregnancy in women with SCD is associated with increased risks of adverse perinatal and maternal outcomes in both low- and high-income countries. TWEETABLE ABSTRACT: This meta-analysis showed worse pregnancy outcomes in women with sickle-cell disease compared with controls.
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Anemia de Células Falciformes , Países Desarrollados , Países en Desarrollo , Complicaciones Hematológicas del Embarazo , Resultado del Embarazo , Femenino , Salud Global , Humanos , Modelos Estadísticos , Oportunidad Relativa , EmbarazoRESUMEN
Partial ablation of the uropygial gland is being used in the poultry industry as a new way to enhance body performance of chickens. However, limited data are available estimating the efficacy of partial uropygialectomy (PU) to improve body organ activity. The present study evaluated the effect of partial ablation of the uropygial gland on the serum growth hormone concentration level and digestive system histology of 120 Akar Putra chickens in 5 trials with 3 replicates per trial. The experimental treatments consisted of a control treatment T1; partial ablation of the uropygial gland was applied in the T2, T3, T4, and T5 treatments at 3, 4, 5, and 6 wk of age, respectively. Feed and water were provided ad libitum. All treatment groups were provided the same diet. Venous blood samples were collected on wk 7, 10, and 12 to assay the levels of growth hormone concentration. On the last d of the experiment, 4 birds per replicate were randomly isolated and euthanized to perform the necropsy. Digestive system organs' cross sections were measured by a computerized image analyzer after being stained with haematoxylin and eosin. In comparison with the control group, surgical removal of the uropygial gland, especially at wk 3, had a greater (P<0.01) effect on the total duodenum, jejunum, and ilium wall thickness. In addition, effects (P<0.05) were observed on the wall thickness of males' cecum and colon. Moreover, the wall layers of the esophagus, proventriculus, gizzard, and rectum were not affected by the treatment. However, removing the uropygial gland showed significant impact (P<0.05) in males' growth hormone concentration level at wk 7 and (P<0.01) effects at wk 12 in both sexes. This study provides a novel and economic alternative to enhance the body performance of poultry in general and Akar Putra chickens particularly.
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Pollos/anatomía & histología , Pollos/metabolismo , Glándulas Exocrinas/cirugía , Tracto Gastrointestinal/anatomía & histología , Hormona del Crecimiento/sangre , Animales , Femenino , Masculino , Distribución AleatoriaRESUMEN
Neutral and niche theories give contrasting explanations for the maintenance of tropical tree species diversity. Both have some empirical support, but methods to disentangle their effects have not yet been developed. We applied a statistical measure of spatial structure to data from 14 large tropical forest plots to test a prediction of niche theory that is incompatible with neutral theory: that species in heterogeneous environments should separate out in space according to their niche preferences. We chose plots across a range of topographic heterogeneity, and tested whether pairwise spatial associations among species were more variable in more heterogeneous sites. We found strong support for this prediction, based on a strong positive relationship between variance in the spatial structure of species pairs and topographic heterogeneity across sites. We interpret this pattern as evidence of pervasive niche differentiation, which increases in importance with increasing environmental heterogeneity.
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Ecosistema , Modelos Teóricos , Árboles/fisiología , Agricultura Forestal , Clima TropicalRESUMEN
The characteristic flavor of exotic tropical fruits is one of their most attractive attributes to consumers. In this article, the enormous diversity of exotic fruit flavors is reviewed. Classifying some of the exotic fruits into two classes on the basis of whether esters or terpenes predominate in the aroma was also attempted. Indeed, as far as exotic tropical fruits are concerned, the majority of fruits have terpenes predominating in their aroma profile. Some of the fruits in this group are the Amazonian fruits such as pitanga, umbu-caja, camu-camu, garcinia, and bacuri. The ester group is made up of rambutan, durians, star fruit, snake fruit, acerola, tamarind, sapodilla, genipap, soursop, cashew, melon, jackfruit, and cupuacu respectively. Also, the role of sulphur-volatiles in some of the exotic fruits is detailed.
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Frutas/química , Odorantes/análisis , Gusto , Clima Tropical , Ésteres/análisis , Olfato , Terpenos/análisis , Compuestos Orgánicos Volátiles/análisisRESUMEN
Despite the general view that patients with sickle-cell disease (SCD) have iron overload, there are reports of iron deficiency in a proportion of these patients. We studied Yemeni patients aged 1-30 years with homozygous SCD to determine their iron status using a set of 4 criteria (low serum iron, low transferrin saturation, high total iron binding capacity and low mean corpuscular volume for age). Of the 75 patients, 44 had never been transfused while 31 patients had received blood transfusions but not during the 3-month period prior to the study. Of the patients, 10 (13.3%) met the criteria for iron deficiency, 9 of whom were from the non-transfused patients (20.5%). The sensitivity and specificity were 40% and 98% respectively for reticulocyte count and 80% and 90% respectively for reticulocyte index. We recommend screening non-transfused SCD patients for iron deficiency.
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Anemia Ferropénica/sangre , Anemia de Células Falciformes/sangre , Transfusión Sanguínea/estadística & datos numéricos , Adolescente , Adulto , Anemia Ferropénica/diagnóstico , Anemia Ferropénica/epidemiología , Anemia de Células Falciformes/epidemiología , Niño , Preescolar , Comorbilidad , Femenino , Humanos , Lactante , Masculino , Recuento de Reticulocitos , Yemen , Adulto JovenRESUMEN
This paper describes the sorption of Pb(ll) from aqueous solution. Oil palm empty fruit bunch (OPEFB) fiber was first grafted with poly(methylacrylate) and then treated with hydroxylammonium chloride in alkaline medium to produce hydroxamic acid (PHA) grafted OPEFB. Sorption of Pb(ll) by PHA-OPEFB was maximum at pH 5. The sorption followed the Langmuir model with maximum capacityof 125.0 mg g-1 at 25 degrees C. The sorption process was exothermic, as shown by the negative value of enthalpy change, Delta H0. The free energy change (DeltaG0) for the sorption was negative, showing that the sorption process was spontaneous. A kinetic study showed that the Pb(ll) sorption followed a second order kinetic model.
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Arecaceae/química , Frutas/química , Ácidos Hidroxámicos/química , Plomo/química , Concentración de Iones de Hidrógeno , Termodinámica , Eliminación de Residuos Líquidos , Contaminantes Químicos del Agua/química , Purificación del Agua/métodosRESUMEN
Tick-borne diseases (TBD) occur in many temperate countries and are economically important in most tropical and subtropical areas, affecting dairy and beef cattle, as well as small ruminants. Four major tick-borne diseases have been detected in eastern and southern Africa: East Coast fever (ECF) caused by Theileria parva, Theiler 1904, anaplasmosis caused by either Anaplasma marginale, Theiler 1910, Anaplasma centrale, Theiler 1911, or Anaplasma ovis, Bevan 1912, babesiosis caused by Babesia bovis, Babes 1988 and Babesia bigemina, Smith & Kilborne 1893, and heartwater caused by Ehrlichia ruminantium Cowdry 1925. A cross-sectional survey was undertaken to determine the antibody prevalence of these TBDs and to identify the risk factors for TBD infections in the Union of the Comoros. In 2016 and 2017, 903 individual animal serum samples were collected from 429 separate farms, where the farmers answered individual questionnaires. The antibody prevalence of anaplasmosis, babesiosis (B. bigemina) and heartwater was determined by enzyme-linked immunosorbent assays (ELISA) and the antibody prevalence of ECF was assessed using an immunofluorescence antibody test (IFAT). The relationship between TBD seropositivity and livestock-related variables was assessed by multivariate analyses with standard logistic regression models. The results showed that these four TBDs were present in the Union of the Comoros with a global antibody prevalence of 15% (95% CI [12.7%; 17.3%]) for anaplasmosis, 9.2% (95% CI [6.5%, 11.9%]) for B. bigemina babesiosis, 5.3% (95% CI [3.2%, 7.4%]) for ECF and 4.6% (95% CI [3.2%, 6%]) for heartwater. We compared these findings with the abundance and distribution of several tick species known to be TBD vectors and we found a significant correlation between Rhipicephalus appendiculatus and ECF, and between Amblyomma variegatum and heartwater. We also found that two major variables were significantly correlated with B. bigemina antibody prevalence ("island" and "breeding area"), four variables were significantly correlated with anaplasmosis antibody seroprevalence ("island", "number of cattle per farmer", "number of farmers per village" and "breeding area"), two were significantly correlated with ECF antibody prevalence ("number of farmers in village" and "presence of ticks"), and three were significantly correlated with heartwater ("island", "number of cattle per farmer" and "number of farmers in the village"). Our findings confirmed livestock exposure to the four targeted TBDs of major concern for livestock development. Consequently, raising farmers' awareness and setting up a period of quarantine should be considered a priority.
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Enfermedades de los Bovinos/epidemiología , Enfermedades de las Cabras/epidemiología , Enfermedades de las Ovejas/epidemiología , Enfermedades por Picaduras de Garrapatas/veterinaria , Animales , Anticuerpos Antibacterianos/análisis , Anticuerpos Antiprotozoarios/análisis , Bovinos , Enfermedades de los Bovinos/microbiología , Enfermedades de los Bovinos/parasitología , Comoras/epidemiología , Estudios Transversales , Ensayo de Inmunoadsorción Enzimática/veterinaria , Técnica del Anticuerpo Fluorescente Indirecta/veterinaria , Enfermedades de las Cabras/microbiología , Enfermedades de las Cabras/parasitología , Cabras , Prevalencia , Factores de Riesgo , Ovinos , Enfermedades de las Ovejas/microbiología , Enfermedades de las Ovejas/parasitología , Oveja Doméstica , Enfermedades por Picaduras de Garrapatas/epidemiología , Enfermedades por Picaduras de Garrapatas/microbiología , Enfermedades por Picaduras de Garrapatas/parasitologíaRESUMEN
OBJECTIVE: To compare clean intermittent self-catheterisation and urethral dilatation with sounds in the management of recurrent urethral strictures. DESIGN: A prospective randomised control trial between repeated urethral dilatation with sounds and use of clean intermittent self-catheterisation in the management of recurrent urethral strictures. SETTING: Kenyatta National Hospital, urology clinics. SUBJECTS: Forty nine patients with recurrent urethral strictures were randomised between clean intermittent catheterisation (CISC) and urethral dilatation with sounds. RESULTS: The urinary flow rates were better in patients on the CISC arm compared to the dilatation arm. Seventy three percent of patients having clutton sounds dilatation developed urinary tract infections compared to 25% of those on CISC. The patients in the CISC arm had a uniformly higher quality of life score than those having sounds dilatation of the urethra. CONCLUSION: Clean intermittent self-catheterisation is an effective and safe way of managing recurrent urethral strictures. It is a better method than repeated clutton sounds dilatation.
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Autocuidado , Estrechez Uretral/terapia , Cateterismo Urinario , Micción , Adolescente , Adulto , Anciano , Femenino , Humanos , Kenia , Masculino , Persona de Mediana Edad , Calidad de Vida , Resultado del TratamientoRESUMEN
The use of modern therapies such as thalidomide, bortezomib and lenalidomide coupled with upfront high-dose therapy and autologous stem cell transplant (ASCT) has resulted in improved survival in patients with newly diagnosed multiple myeloma (MM). However, patients with relapsed/refractory multiple myeloma (RRMM) often have poorer clinical outcomes and might benefit from novel therapeutic strategies. Emerging therapies, such as deacetylase inhibitors, monoclonal antibodies and new proteasome inhibitors, appear promising and may change the therapeutic landscape in RRMM. A limited number of studies has shown a benefit with salvage ASCT in patients with RRMM, although there remains ongoing debate about its timing and effectiveness. Improvement in transplant outcomes has re-ignited a debate on the timing and possible role for salvage ASCT and allogeneic stem cell transplant in RRMM. As the treatment options for management of patients with RRMM become increasingly complex, physicians must consider both disease- and patient-related factors in choosing the appropriate therapeutic approach, with the goal of improving efficacy while minimizing toxicity.
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Antineoplásicos/uso terapéutico , Mieloma Múltiple/terapia , Trasplante de Células Madre/métodos , Aloinjertos , Autoinjertos , HumanosRESUMEN
This study evaluated the effect of partial uropygialectomy (PU) on carcass traits of male and female Akar Putra chickens. Sixty chicks of each sex were evenly distributed into 5 treatment groups with 3 replicates per group containing 4 males and 4 females each, and reared for 12 wk. Homogeneity of the groups was satisfied with regard to the parity. Experimental treatments consisted of a control treatment (T1), and partial ablation of the uropygial gland was applied on the second, third, fourth, and fifth treatments at 3, 4, 5, and 6 wk of age, respectively. The chickens were fed ad libitum the same diets (1 to 13 d: starter; 14 d to slaughter: finisher). On the last d of the experiment, 12 birds were randomly selected from each treatment group (2 males and 2 females per replicate) and slaughtered to determine carcass characteristics, which included carcass weight, dressing percentage with or without eating giblets, and the relative weights of heart, liver, gizzard, thighs, wings, breast, back, and neck. From the results of the study, it was shown that the partial ablation of the uropygial gland at all ages had certain dependent effects concerning some carcass parameters, as shown by higher breast and back relative weights in males and breast relative weight in females. As a consequence, a positive effect also was noticed regarding the carcass morphology in terms of the increase in dressing percentage with or without eating giblets thus leading to an increase in the body weight and carcass weight. Furthermore, the best result was obtained in the second treatment when PU was applied at 3 wk of age compared with other experimental groups. Moreover, the current study provides a novel and economic alternative to enhance the body performance of poultry in general and Akar Putra chicken particularly.
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Pollos , Carne/normas , Glándulas Sebáceas/cirugía , Crianza de Animales Domésticos , Animales , Pollos/cirugía , Femenino , Calidad de los Alimentos , MasculinoRESUMEN
Reduced-intensity stem cell transplantation (RIST) has been shown to be a safe and useful alternative transplant method for patients including elderly and medically unfit patients. RIST conditioning regimens vary widely in the intensity of myeloablation, immunoablation, and antileukemia effects, and thus optimal regimen for each disease entity is yet to be determined. Most reports on RIST to date are small, single-institution experiences or retrospective studies with heterogeneous patient populations and primary diseases, complicating any direct comparison between studies. In acute myeloid leukemia (AML), moderate-intensity regimens may be effective, achieving 30-70% 1-year disease-free survival in various series, but minimal-intensity regimens are associated with high relapse rates. In acute lymphoblastic leukemia (ALL), not even moderate-intensity regimens are effective and most patients with advanced ALL relapse post transplant. Thus, the risk/benefit ratios of graft-versus-host disease/graft-versus-leukemia effect differ among diseases. Larger, prospective, multi-center clinical trials are needed to determine the best use of RIST in hematologic malignancies.
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Trasplante de Células Madre Hematopoyéticas/métodos , Leucemia Mieloide Aguda/terapia , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Trasplante Homólogo/métodos , Adolescente , Adulto , Anciano , Ensayos Clínicos como Asunto , Supervivencia sin Enfermedad , Enfermedad Injerto contra Huésped , Humanos , Persona de Mediana Edad , Estudios Multicéntricos como Asunto , Recurrencia , Factores de Tiempo , Quimera por Trasplante , Acondicionamiento Pretrasplante , Resultado del TratamientoRESUMEN
Pegfilgrastim is equivalent to daily filgrastim after standard dose chemotherapy in decreasing the duration of neutropenia. Daily filgrastim started within 1-4 days after autologous stem cell transplant (ASCT) leads to significant decrease in time to neutrophil engraftment. We undertook a study of pegfilgrastim after high-dose chemotherapy (HDC) and ASCT. In all, 38 patients with multiple myeloma or lymphoma, eligible to undergo HDC and ASCT, were enrolled. Patients received a single dose of 6 mg pegfilgrastim subcutaneously 24 h after ASCT. There were no adverse events secondary to pegfilgrastim. All patients engrafted neutrophils and platelets with a median of 10 and 18 days, respectively. The incidence of febrile neutropenia was 49% (18/37). Neutrophil engraftment results were compared to a historical cohort of patients who received no growth factors or prophylactic filgrastim after ASCT. Time to neutrophil engraftment using pegfilgrastim was comparable to daily filgrastim and was shorter than in a historical group receiving no filgrastim (10 vs 13.7 days, P<0.001). Pegfilgrastim given as a single fixed dose of 6 mg appears to be safe after HDC and ASCT. It accelerates neutrophil engraftment comparable to daily filgrastim after ASCT. Pegfilgrastim may be convenient to use in outpatient transplant units.
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Factor Estimulante de Colonias de Granulocitos/administración & dosificación , Neutropenia/prevención & control , Trasplante de Células Madre de Sangre Periférica/métodos , Adulto , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Femenino , Filgrastim , Supervivencia de Injerto , Neoplasias Hematológicas/complicaciones , Neoplasias Hematológicas/terapia , Humanos , Cinética , Masculino , Persona de Mediana Edad , Mielopoyesis/efectos de los fármacos , Neutropenia/tratamiento farmacológico , Neutrófilos/fisiología , Trasplante de Células Madre de Sangre Periférica/efectos adversos , Polietilenglicoles , Proteínas Recombinantes , Trasplante AutólogoRESUMEN
BACKGROUND: Breast cancer is the first cancer among females in the Kingdom of Saudi Arabia, accounting for 27.4% of all newly diagnosed female cancers in 2010. There are several risk factors affecting the incidence of breast cancer where some factors influence the risk more than the others. AIM: We aimed to identify the different risk factors related to breast cancer among females participating in the breast-screening program in Riyadh, KSA. METHODS: Based on data from phase-I of the breast-screening program, a case-control study was conducted on women living in Riyadh, KSA. A sample of 349 women (58 cases and 290 controls) was recruited to examine the different breast cancer correlates. Multivariate regression model was built to investigate the most important risk factors. RESULTS: The mean age of cases was 48.5±7.1 years. Age at marriage, number of pregnancy, age at menopause, oral contraceptive pills, breast feeding and family history of breast cancer in first-degree relative were identified as the most important correlates among the studied cohort. CONCLUSIONS: The findings of the current work suggested that age at marriage, age at menopause ⩾50 years and 1st degree family history of breast cancer were risk factors for breast cancer, while, age at menopause <50 years, number of pregnancies and practicing breast feeding were protective factors against breast cancer. There was no effect of body mass index or physical inactivity. Further studies are needed to explore the hereditary, familial and genetic background risk factors in Saudi population.
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Neoplasias de la Mama/epidemiología , Adulto , Anciano , Neoplasias de la Mama/diagnóstico , Estudios de Casos y Controles , Detección Precoz del Cáncer , Femenino , Humanos , Incidencia , Tamizaje Masivo , Persona de Mediana Edad , Oportunidad Relativa , Factores de Riesgo , Arabia Saudita/epidemiologíaRESUMEN
3'-Azido-2',3'-dideoxythymidine (AZT), the thymidine analogue used against human immunodeficiency virus 1 (HIV-1), exhibits bone marrow and blood toxicity in humans, presumably as the result of genotoxic mechanisms induced by incorporation of AZT into eukaryotic DNA. Preferential incorporation of AZT into telomeric regions of DNA of Chinese hamster ovary (CHO) cells has been previously demonstrated by immunofluorescence using anti-AZT antibodies. We quantitatively compared the amount of [H-3]-AZT bound to telomeric and non-telomeric sequences of CHO cell DNA. DNA from cells exposed to [H-3]-AZT was digested by a mixture of restriction enzymes, frequent cutters in the overall genome, without restriction sites in the telomeric repeat. As a result, the telomeric fraction (TF): isolated by separation columns, comprised longer sequences (> 2 kb) than the non-telomeric fraction (NTF). Radioactivity associated with each fraction revealed a three fold increase in [H-3]-AZT incorporated in the TF compared with the NTF. No preferential telomeric binding was detected for [H-3]-thymidine (Tdr) or [H-3]-5'bromodeoxyuridine (BrdU) in similar experiments or in DNA of AZT-treated mouse primary fibroblasts, cells with large telomeric repeats that lack telomerase. When the chromosomal ends of high molecular weight [H-3]-AZT-DNA were digested with Pal 31, the radioactivity was double in the TF compared with the NTF. Therefore incorporation of AZT in CHO immortalized cells but not in primary fibroblasts (that lack telomerase) indirectly shows that AZT incorporation could be telomerase-mediated.
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Some chemical carcinogens localize preferentially in mitochondrial DNA (mtDNA) when compared with genomic DNA (gDNA). Here we compare the ability of cisplatin (cis-diamminedichloroplatinum[II]) to induce DNA adducts in both genomic and mtDNA of Chinese hamster ovary (CHO) cells in culture. Cytotoxicity was examined by cell survival 4, 8 and 24 h after exposure to 50 microM cisplatin. Cisplatin-DNA adducts were measured in DNA from nuclear and mitochondrial fractions by dissociation-enhanced lanthanide fluoroimmunoassay (DELFIA), a sensitive competitive microtiter-based immunoassay utilizing antiserum elicited against cisplatin-modified DNA. An additional comparison of cisplatin-DNA binding in both compartments was performed by immunoelectron microscopy using the cisplatin-DNA antiserum and colloidal gold. DELFIA analysis of cisplatin-DNA adducts in gDNA and mtDNA showed a six-fold higher incorporation of drug into mtDNA as compared to gDNA. Morphometric studies of colloidal gold distribution in photomicrographs of CHO cells showed mtDNA to contain a four-fold higher concentration of cisplatin as compared to nuclear DNA. Therefore, both methods demonstrated a preferential binding of cisplatin to mtDNA versus gDNA.
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Cisplatino/metabolismo , Aductos de ADN , ADN Mitocondrial/metabolismo , Animales , Células CHO , Núcleo Celular/genética , Núcleo Celular/ultraestructura , Cisplatino/toxicidad , Cricetinae , Fluoroinmunoensayo , Genoma , Microscopía Inmunoelectrónica , Mitocondrias/genética , Mitocondrias/ultraestructuraRESUMEN
1,5-Di-(2-chlorophenyl)-3-mercaptoformazan (2,2'-dichlorodithizone) has been synthesized and characterized. Its acid dissociation constant and its partition coefficient between carbon tetrachloride and water have been determined. The introduction of chlorine atoms into the ortho positions of the phenyl nuclei of dithizone was found to affect the visible electronic spectra of the reagent and its metal complexes. The ranges of pH for complete extraction, and the extraction constants, for the Hg(II), Cu(II), Zn(II), Cd(II), and Pb(II) complexes have been determined. The stability constants of the Cu(II) and Zn(II) complexes were also determined. Discrepancies between the present extensive data and the corresponding earlier data have been attributed to use of impure materials and/or inaccuracy of measurements in the earlier work.
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Poly(hydroxamic acid) chelating ion-exchange resin was prepared from crosslinked poly(methacrylate) beads. The starting polymer was prepared by a suspension polymerization of methacrylate and divinyl benzene. Conversion of the ester groups into the hydroxamic acid was carried out by treatment with hydroxylamine in an alkaline solution. Hydroxamic acid capacity of the product was 2.71 mmol/g. The resin exhibited high affinity towards Fe(III) and Pb ions and its capacities for Fe(III), Pb, Cu, Ni and Co ions were pH dependent. The ability of the resin to carry out the separation of Fe(III)CuCo/Ni and PbNi ions is also reported.