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1.
Biochim Biophys Acta Mol Basis Dis ; 1869(8): 166835, 2023 12.
Artículo en Inglés | MEDLINE | ID: mdl-37558009

RESUMEN

Different SOD1 proteoforms are implicated## in both familial and sporadic cases of Amyotrophic Lateral Sclerosis (ALS), an aging-associated disease that affects motor neurons. SOD1 is crucial to neuronal metabolism and health, regulating the oxidative stress response and the shift between oxidative-fermentative metabolism, which is important for astrocyte-neuron metabolic cooperation. Neurons have a limited capacity to metabolize methylglyoxal (MGO), a potentially toxic side product of glycolysis. MGO is highly reactive and can readily posttranslationally modify proteins, in a reaction known as glycation, impacting their normal biology. Here, we aimed to investigate the effect of glycation on the aggregation and toxicity of human SOD1WT (hSOD1WT). Cells with deficiency in MGO metabolism showed increased levels of hSOD1WT inclusions, displaying also reduced hSOD1WT activity and viability. Strikingly, we also found that the presence of hSOD1WT in stress granules increased upon MGO treatment. The treatment of recombinant hSOD1WT with MGO resulted in the formation of SDS-stable oligomers, specially trimers, and thioflavin-T positive aggregates, which can promote cell toxicity and TDP-43 pathology. Together, our results suggest that glycation may play a still underappreciated role on hSOD1WT and TDP-43 pathologies in sporadic ALS, which could open novel perspectives for therapeutic intervention.


Asunto(s)
Esclerosis Amiotrófica Lateral , Humanos , Superóxido Dismutasa-1/genética , Esclerosis Amiotrófica Lateral/patología , Superóxido Dismutasa/metabolismo , Reacción de Maillard , Óxido de Magnesio , Neuronas Motoras/metabolismo , Proteínas de Unión al ADN/metabolismo
2.
Front Med (Lausanne) ; 10: 1022746, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37089614

RESUMEN

Background: Although research on HIV self-testing (HIVST) has rapidly increased, few studies have explored HIVST uptake in female sex workers (FSW), and none in Malaysia. Therefore, we endeavored to assess the willingness to use HIVST in this at-risk, vulnerable population. Methods: A cross-sectional survey study was conducted among 113 HIV-negative Malaysian FSW in 2017. Participants were recruited using advertisements on social media, flyers, and direct referrals from community-based organizations. Data were collected using self-administered surveys. Multivariable logistic regression was used to identify correlates of willingness to use HIVST. Results: Nearly a third of participants (30.1%) reported they would be willing to use HIVST. Multivariable analyses adjusting for Malay ethnicity, stable housing, living in Kuala Lumpur (KL), years in sex work, age of first sex work, childhood sexual assault, history of HIV testing, and previously in prison indicated that living in KL [adjusted odds ratio (aOR) = 5.214, p = 0.0137] was associated with a greater willingness to use HIVST. In contrast, having stable housing (aOR = 0.100, p = 0.0064) was negatively associated with willingness to use HIVST. Conclusions: Our results indicate that HIVST may potentially enhance the uptake of HIV testing among FSWs living in an urban environment and experiencing unstable housing, but an overall willingness to use HIVST is low. These findings highlight the need for efforts to increase awareness of HIVST among FSWs and additional research on the effective implementation of HIVST for FSW.

3.
J Cell Biochem ; 123(11): 1808-1816, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-35944097

RESUMEN

Cancer-related metabolic features are in part maintained by hexokinase 2 upregulation, which leads to high levels of glucose-6-phosphate (G6P) and is needed to provide energy and biomass to support rapid proliferation. Using a humanized model of the yeast Saccharomyces cerevisiae, we explored how human hexokinase 2 (HK2) behaves under different nutritional conditions. At high glucose levels, yeast presents aerobic glycolysis through a regulatory mechanism known as catabolic repression, which exerts a metabolic adaptation like the Warburg effect. At high glucose concentrations, HK2 did not translocate into the nucleus and was not able to shift the metabolism toward a highly glycolytic state, in contrast to the effect of yeast hexokinase 2 (Hxk2), which is a crucial protein for the control of aerobic glycolysis in S. cerevisiae. During the stationary phase, when glucose is exhausted, Hxk2 is shuttled out of the nucleus, ceasing catabolic repression. Cells harvested at this condition display low glucose consumption rates. However, glucose-starved cells expressing HK2 had an increased capacity to consume glucose. In those cells, HK2 localized to mitochondria, becoming insensitive to G6P inhibition. We also found that the sugar trehalose-6-phosphate (T6P) is a human HK2 inhibitor, like yeast Hxk2, but was not able to inhibit human HK1, the isoform that is ubiquitously expressed in almost all mammalian tissues. In contrast to G6P, T6P inhibited HK2 even when HK2 was associated with mitochondria. The binding of HK2 to mitochondria is crucial for cancer survival and proliferation. T6P was able to reduce the cell viability of tumor cells, although its toxicity was not impressive. This was expected as cell absorption of phosphorylated sugars is low, which might be counteracted using nanotechnology. Altogether, these data suggest that T6P may offer a new paradigm for cancer treatment based on specific inhibition of HK2.


Asunto(s)
Hexoquinasa , Fosfatos de Azúcar , Animales , Humanos , Hexoquinasa/metabolismo , Saccharomyces cerevisiae/metabolismo , Glucólisis , Glucosa/metabolismo , Mamíferos
4.
Health Psychol ; 41(2): 115-120, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34855415

RESUMEN

OBJECTIVE: Vaccination against coronavirus disease 2019 (COVID-19) is a promising avenue for arresting the COVID-19 pandemic, yet suboptimal rates of vaccine uptake in at-risk groups may hinder efficacy and worsen existing health disparities. People with opioid use disorder (OUD) are likely to face increased vulnerability to COVID-19 due to a confluence of biological and social risk factors. We sought to assess factors associated with willingness to vaccinate against COVID-19 in people with OUD. METHOD: Phone surveys were conducted from May to October 2020 with participants enrolled in an urban methadone maintenance program (MMP). Participants were adults who met DSM-5 criteria for OUD and reported injection drug use or sexual risk behavior. Participants were asked about their willingness to receive a highly or partially effective vaccine. Provider trust was assessed using the Trust in Physician scale. Multinomial regression was used to assess demographic and psychosocial factors related to vaccination willingness. RESULTS: We surveyed 109 people with OUD enrolled in a MMP (M = 47 years; 56% women; 59% White, 23% Black/African American, 14.4% Hispanic/Latinx; 1.8% other). Participants who identified as Black or African American were significantly less likely to endorse willingness to use a partially effective COVID-19 vaccine (adjusted odds ratio [aOR] = .10; 95% confidence interval (CI) [.02, .61], p = .012), although not necessarily less willing to receive a highly effective vaccine (aOR = .40; 95% CI [.09, 1.73], p = .219; n.s.). Trust in physician was positively associated with willingness to use a partially effective vaccine (aOR = 1.12; 95% CI [1.02, 1.23], p = .017), but was not significantly associated with willingness to receive a highly effective vaccine (aOR = 1.07; 95% CI [.98, 1.16], p = .162, n.s) Conclusions: Proactive outreach from trustworthy sources will be needed to counter vaccine hesitancy in people with OUD, especially among Black Americans with OUD. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Asunto(s)
COVID-19 , Trastornos Relacionados con Opioides , Adulto , COVID-19/prevención & control , Vacunas contra la COVID-19 , Femenino , Humanos , Masculino , Trastornos Relacionados con Opioides/epidemiología , Pandemias/prevención & control , SARS-CoV-2 , Confianza , Vacunación , Vacilación a la Vacunación
5.
J Subst Abuse Treat ; 117: 108058, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32811633

RESUMEN

In the Bangkok Tenofovir Study of oral pre-exposure prophylaxis (PrEP; TDF/FTC), adherence was poor. Long-acting injectable pre-exposure prophylaxis (LAI-PrEP) for HIV prevention may help overcome adherence challenges and is currently being tested in clinical trials, but not in people who use drugs (PWUD), an important key population that remains highly vulnerable to HIV. Since PWUD are not currently included in trials of LAI-PrEP, we sought to examine awareness about LAI-PrEP and factors associated with willingness to use LAI-PrEP in this understudied population. Participants included 234 HIV-negative people with opioid use disorder and self-reported HIV-risk behaviors recruited from Connecticut's largest addiction treatment program. We analyzed data from a standardized assessment using audio computer-assisted self-interview (ACASI) to assess the independent factors associated with willingness to use LAI-PrEP. While only 25.6% of participants were aware of LAI-PrEP (67.1% had heard of oral PrEP), after being given a description of it, 73.5% were willing to use it, if it were available. Participants were most commonly concerned about long-term side effects (76.9%) of LAI-PrEP. Independent correlates of willingness to use LAI-PrEP were female sex (aOR = 2.181, p = 0.018), recent visit to healthcare provider (aOR = 2.9, p = 0.023), high perceived risk of acquiring HIV (aOR = 3.3, p = 0.007), and having previously taken oral PrEP (aOR = 3.284, p = 0.017). Findings suggest that PWUD are highly interested in PrEP, especially in LAI-PrEP formulations. Our results indicate the potential for LAI-PrEP, as an alternative to oral daily PrEP, to be implemented into existing evidence-based HIV-based HIV prevention efforts that target high-risk PWUD.


Asunto(s)
Fármacos Anti-VIH , Infecciones por VIH , Preparaciones Farmacéuticas , Profilaxis Pre-Exposición , Fármacos Anti-VIH/uso terapéutico , Femenino , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/prevención & control , Homosexualidad Masculina , Humanos , Masculino , Aceptación de la Atención de Salud , Tailandia
6.
Clin Radiol ; 75(7): 561.e13-561.e24, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32321647

RESUMEN

AIM: To outline the disease burden of breast tuberculosis (TB) as a quantitative analysis amongst three tertiary hospitals in South Africa, with correlation to their clinical, demographic, and imaging features. MATERIALS AND METHODS: A retrospective analysis was undertaken over an 18-month period (01/01/2017-30/06/2018) of all patients undergoing laboratory investigations for breast disease at the mammography departments of these three tertiary centres. RESULTS: The prevalence of breast TB was 2.5% (n=62) of 2,516 patients. The median age of presentation was 38.5 years (interquartile range [IQR] 33-45). HIV status was known in 45 patients, of whom 36 were HIV infected (80%, 95% CI: 0.65-0.90, p<0.0001). Based on the ultrasound and/or mammogram findings, the patients were classified into five categories: TB breast abscess (40.3%), inflammatory/disseminated (24.2%), isolated TB lymphadenitis (22.6%), nodular (11.3%), and sclerosing form (1.6%). Histology demonstrated necrotising granulomatous inflammation in 57 cases (92%). Acid-fast bacilli (AFB) were positive in 8.1% (n=5) of the cytology and 16.1% (n=10) of the histology specimens. Culture for Mycobacterium tuberculosis was positive in 27% (17 cases), and in 12.9% (n=8). AFB were detected histologically using polymerase chain reaction (PCR) testing. CONCLUSION: Knowledge of the varied clinical and radiological features is necessary to maintain a high degree of suspicion to prevent misdiagnoses, inappropriate management, and complications. Ultrasound-guided core biopsy rather than fine-needle aspiration (FNA) is advocated as the first-line intervention in diagnosing or excluding this disease, as it yields a better tissue sample and more often a positive diagnosis.


Asunto(s)
Enfermedades de la Mama/diagnóstico por imagen , Mamografía , Tuberculosis/diagnóstico por imagen , Adulto , Mama/diagnóstico por imagen , Mama/microbiología , Mama/patología , Enfermedades de la Mama/microbiología , Enfermedades de la Mama/patología , Femenino , Infecciones por VIH/complicaciones , Humanos , Persona de Mediana Edad , Estudios Retrospectivos , Sudáfrica/epidemiología , Tuberculosis/etiología , Tuberculosis/patología
7.
S Afr Med J ; 109(3): 159-163, 2019 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-30834871

RESUMEN

BACKGROUND: Breast cancer is the most common cancer in women in many low- and middle-income countries, and often presents at an advanced stage that affects prognosis irrespective of the care available. Although patient-related delay is commonly cited, the reasons for delay and the relationship of delay to stage are still poorly documented, especially in Africa. OBJECTIVES: To identify where patient-related socioeconomic delays occur and how these relate to stage at presentation. METHODS: Consecutive women with a new breast cancer diagnosis were prospectively invited to complete a questionnaire on their socioeconomic characteristics and ability to access care. Clinical stage at presentation was documented. RESULTS: Over 14 months, 252 women completed the questionnaire (response rate 71.6%). Their median age was 55 years (interquartile range 44 - 65), with 26.5% aged <45 years. Stage at presentation was stage 1 in 15.5% of patients, stage 2 in 28.5% and stage 3 in 56.0%. Almost a third of the patients (30.4%) presented with a T4 tumour (6.1% inflammatory). Total delay in presenting to the breast clinic was significantly associated with locally advanced stage at presentation (p=0.021). Average delay differed between early stage (1.5 months) and locally advanced (2.5 months), and most delay occurred between acknowledging a breast symptom and seeking care. The least delay was between attending a health service and presenting at the open-access breast clinic, with 75.0% presenting within 1 month. Factors associated with delay were difficulties with transport, low level of education and fear of missing appointments due to work. CONCLUSIONS: Most women delayed in seeking breast care. Facilitating direct access to specialist breast clinics may reduce delays in presentation and improve time to diagnosis and care.


Asunto(s)
Neoplasias de la Mama/diagnóstico , Diagnóstico Tardío/estadística & datos numéricos , Accesibilidad a los Servicios de Salud/estadística & datos numéricos , Aceptación de la Atención de Salud/estadística & datos numéricos , Adulto , Anciano , Neoplasias de la Mama/patología , Neoplasias de la Mama/psicología , Diagnóstico Tardío/psicología , Femenino , Encuestas de Atención de la Salud , Humanos , Persona de Mediana Edad , Estadificación de Neoplasias , Aceptación de la Atención de Salud/psicología , Estudios Prospectivos , Factores Socioeconómicos , Sudáfrica , Servicios Urbanos de Salud
8.
S. Afr. j. surg. (Online) ; 57(1): 12-18, 2019. ilus
Artículo en Inglés | AIM (África) | ID: biblio-1271043

RESUMEN

Background: The disparity in breast cancer survival in Africa is often linked to poor education and awareness leading to late diagnosis and subsequent reduced survival. This study was designed to explore the relationship of attitudes and beliefs held regarding breast cancer to the stage and delay to diagnosis in South Africa. This study provies an epidemiological analysis of the spectrum of disease and outcomes of primary amputation for diabetic foot sepsis in a regional rural hospital.Methods: Women attending an open-access breast unit over 14 months with newly-diagnosed breast cancer answered a survey regarding their fears and beliefs of breast cancer care. Questions addressed demographic, socioeconomic and educational factors linked to delay, and documented time taken to care. Odds ratio with 95% confidence intervals were calculated to identify factors associated with advanced stage at presentation and delay greater than six months. Results: Of the 233 participants the median (IQR) age was 56 years (46­65). The most common stage at presentation was Stage 3 (55%), with 30.5% presenting with T4 tumour at presentation. Most women believed cancer could be beaten (90.0%), and their families would support them (92.8%). They disagreed that cancer was a curse (93.8%), punishment (90.5%) or that alternative therapies or traditional healing would cure their cancer (75.3% and 85.5% respectively). On univariate analysis, age under 45 years and transport difficulties predicted advanced stage at presentation. No socio-economic factors or beliefs increased the risk of delay to presentation. Conclusion: Participants' beliefs about their new breast cancer were most commonly appropriate, and showed a low level of fatalism, in contrast to other studies in Africa. Whilst raising awareness may be important, efforts to increase awareness alone may not directly prevent the likelihood of late or advanced diagnosis in this population


Asunto(s)
Neoplasias de la Mama/diagnóstico , Cultura , Progresión de la Enfermedad , Sudáfrica , Salud Urbana
9.
S. Afr. med. j. (Online) ; 109(3): 159-163, 2019.
Artículo en Inglés | AIM (África) | ID: biblio-1271216

RESUMEN

Background. Breast cancer is the most common cancer in women in many low- and middle-income countries, and often presents at an advanced stage that affects prognosis irrespective of the care available. Although patient-related delay is commonly cited, the reasons for delay and the relationship of delay to stage are still poorly documented, especially in Africa. Objectives. To identify where patient-related socioeconomic delays occur and how these relate to stage at presentation. Methods. Consecutive women with a new breast cancer diagnosis were prospectively invited to complete a questionnaire on their socioeconomic characteristics and ability to access care. Clinical stage at presentation was documented. Results. Over 14 months, 252 women completed the questionnaire (response rate 71.6%). Their median age was 55 years (interquartile range 44 - 65), with 26.5% aged <45 years. Stage at presentation was stage 1 in 15.5% of patients, stage 2 in 28.5% and stage 3 in 56.0%. Almost a third of the patients (30.4%) presented with a T4 tumour (6.1% inflammatory). Total delay in presenting to the breast clinic was significantly associated with locally advanced stage at presentation (p=0.021). Average delay differed between early stage (1.5 months) and locally advanced (2.5 months), and most delay occurred between acknowledging a breast symptom and seeking care. The least delay was between attending a health service and presenting at the open-access breast clinic, with 75.0% presenting within 1 month. Factors associated with delay were difficulties with transport, low level of education and fear of missing appointments due to work. Conclusions. Most women delayed in seeking breast care. Facilitating direct access to specialist breast clinics may reduce delays in presentation and improve time to diagnosis and care


Asunto(s)
Neoplasias de la Mama/diagnóstico , Diagnóstico Tardío , Sudáfrica , Factores de Tiempo , Población Urbana
10.
FEMS Yeast Res ; 18(6)2018 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-30007297

RESUMEN

Trehalose on both sides of the bilayer is a requirement for full protection of membranes against stress. It was not known yet how trehalose, synthesized in the cytosol when dividing Saccharomyces cerevisiae cells are shifted from 28°C to 40°C, is transported to the outside and degraded when cells return to 28°C. According to our results, the lack of Agt1, a trehalose transporter, although had not affected trehalose synthesis, reduced cell tolerance to 51°C and increased lipid peroxidation. The damage was reversed when external trehalose was added during 40°C adaptation, confirming that the reason for the agt1Δ sensitivity is the absence of trehalose at the outside of the lipid bilayer. The 40-28°C condition caused cytosolic trehalase (Nth1) activation, reducing intracellular trehalose and, consequently, the survival rates after 51°C. Although lower than nth1Δ strain, cells deficient in acid trehalase (ath1Δ)  maintained increased trehalose levels after 40°C-28°C shift, which conferred protection against 51°C. Both Ath1 and Agt1 were found into vesicles near to plasma membrane in response to stress. This suggests that Agt1 containing vesicles would fuse with the membrane under 40°C to transport part of the cytosolic trehalose to the outside. By a similar mechanism, Ath1 would reach the cell surface to hydrolyze the external trehalose but only when the stress would be over. Corroborating this conclusion, Ath1 activity in soluble cell-free extracts increased after 40°C adaptation but decreased when cells returned to 28°C. During 40°C, Ath1 is confined into vesicles, avoiding the cleavage of the outside trehalose.


Asunto(s)
Respuesta al Choque Térmico , Proteínas de Transporte de Monosacáridos/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/fisiología , Simportadores/metabolismo , Trehalasa/metabolismo , Trehalosa/metabolismo , Transporte Biológico , Membrana Celular/metabolismo , Vesículas Citoplasmáticas/metabolismo , Respuesta al Choque Térmico/efectos de los fármacos , Peroxidación de Lípido/efectos de los fármacos , Proteínas de Transporte de Monosacáridos/genética , Mutación , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Simportadores/genética , Trehalasa/genética , Trehalosa/farmacología
11.
Mol Neurobiol ; 55(6): 5269-5281, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28884318

RESUMEN

Among the familial forms of amyotrophic lateral sclerosis (fALS), 20% are associated with the Cu,Zn-superoxide dismutase (Sod1). fALS is characterized by the accumulation of aggregated proteins and the increase in oxidative stress markers. Here, we used the non-invasive bimolecular fluorescence complementation (BiFC) assay in human H4 cells to investigate the kinetics of aggregation and subcellular localization of Sod1 mutants. We also studied the effect of the different Sod1 mutants to respond against oxidative stress by following the levels of reactive oxygen species (ROS) after treatment with hydrogen peroxide. Our results showed that only 30% of cells transfected with A4VSod1 showed no inclusions while for the other Sod1 mutants tested (L38V, G93A and G93C), this percentage was at least 70%. In addition, we found that 10% of cells transfected with A4VSod1 displayed more than five inclusions per cell and that A4V and G93A Sod1 formed inclusions more rapidly than L38V and G93C Sod1. Expression of WTSod1 significantly decreased the intracellular oxidation levels in comparison with expression of fALS Sod1 mutants, suggesting the mutations induce a functional impairment. All fALS mutations impaired nuclear localization of Sod1, which is important for maintaining genomic stability. Consistently, expression of WTSod1, but not of fALS Sod1 mutants, reduced DNA damage, as measured by the comet assay. Altogether, our study sheds light into the effects of fALS Sod1 mutations on inclusion formation, dynamics, and localization as well as on antioxidant response, opening novel avenues for investigating the role of fALS Sod1 mutations in pathogenesis.


Asunto(s)
Esclerosis Amiotrófica Lateral/enzimología , Esclerosis Amiotrófica Lateral/genética , Modelos Biológicos , Mutación/genética , Multimerización de Proteína , Superóxido Dismutasa/genética , Línea Celular Tumoral , Núcleo Celular/metabolismo , Daño del ADN , Humanos , Transporte de Proteínas , Especies Reactivas de Oxígeno/metabolismo
12.
Appl Biochem Biotechnol ; 181(3): 914-924, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27796871

RESUMEN

In some pathogens, trehalose biosynthesis is induced in response to stress as a protection mechanism. This pathway is an attractive target for antimicrobials as neither the enzymes, Tps1, and Tps2, nor is trehalose present in humans. Accumulation of T6P in Candida albicans, achieved by deletion of TPS2, resulted in strong reduction of fungal virulence. In this work, the effect of T6P on Tps1 activity was evaluated. Saccharomyces cerevisiae, C. albicans, and Candida tropicalis were used as experimental models. As expected, a heat stress induced both trehalose accumulation and increased Tps1 activity. However, the addition of 125 µM T6P to extracts obtained from stressed cells totally abolished or reduced in 50 and 60 % the induction of Tps1 activity in S. cerevisiae, C. tropicalis, and C. albicans, respectively. According to our results, T6P is an uncompetitive inhibitor of S. cerevisiae Tps1. This kind of inhibitor is able to decrease the rate of reaction to zero at increased concentrations. Based on the similarities found in sequence and function between Tps1 of S. cerevisiae and some pathogens and on the inhibitory effect of T6P on Tps1 activity observed in vitro, novel drugs can be developed for the treatment of infectious diseases caused by organisms whose infectivity and survival on the host depend on trehalose.


Asunto(s)
Candida albicans/enzimología , Candida tropicalis/enzimología , Inhibidores Enzimáticos/química , Glucosiltransferasas/antagonistas & inhibidores , Saccharomyces cerevisiae/enzimología , Fosfatos de Azúcar/química , Trehalosa/análogos & derivados , Candida albicans/patogenicidad , Candida tropicalis/patogenicidad , Candidiasis/tratamiento farmacológico , Candidiasis/enzimología , Inhibidores Enzimáticos/farmacología , Especificidad de la Especie , Fosfatos de Azúcar/farmacología , Trehalosa/química , Trehalosa/farmacología
13.
Anal Bioanal Chem ; 389(2): 555-61, 2007 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-17653703

RESUMEN

A new conceptual approach towards iteratively constructing chromatographic retention time/index models is presented. The approach is applicable where there is potential structural uncertainty in a number of members of the dataset used in constructing the model, and where limited spectroscopic information is available to guide the process. The model is demonstrated on a suite of biomass combustion-derived methoxyphenols for which gas chromatographic polydimethylsiloxane retention index data was available in the literature, but where there was ambiguity regarding the identity of several members of the dataset. The retention property model is populated by sequentially screening a series of candidate structures that meet basic mass spectrometric requirements by using a multiple linear regression model containing molecular and physicochemical properties that have been previously shown to yield reliable predictions of chromatographic behaviour within a compound class. The criteria for deciding on the likely structure(s) out of a suite of candidate structures is based upon the improved quality of fit the most probable structure gives the regression model relative to other candidate structures.


Asunto(s)
Biomasa , Cromatografía de Gases/métodos , Modelos Teóricos , Fenoles/química
14.
J Reprod Med ; 40(9): 611-3, 1995 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-8576874

RESUMEN

OBJECTIVE: The purpose of cold knife conization is to ligate the descending cervical branch of the uterine artery and thus to decrease bleeding. The aim of this study was to investigate the actual frequency of ligation. STUDY DESIGN: Two lateral sutures were placed in the cervix at the 3 and 9 o'clock positions in 97 patients (194 sutures) as part of vaginal hysterectomy. The position of each suture was determined during evaluation of the surgical specimen. RESULTS: Because the specimens from 10 patients contained only single sutures, only 184 sutures were actually evaluated. Upon microscopic examination, 50 of the 184 (27%) appeared to contain no artery. Of the remaining 134 sutures, 95 (71%) enclosed an artery, and 9 (7%) lay within a 10 x field of a branch. Only 30 sutures (22%) missed the artery entirely. Thus, in the 73% of cases where an artery of significant size could be identified, the artery lay within a lateral stitch 71% of the time. CONCLUSION: If the descending cervical branch of the uterine artery supplies most of the blood to the cervix, advance placement of lateral sutures would be expected to reduce blood loss during conization.


Asunto(s)
Cuello del Útero/cirugía , Conización/métodos , Hemostasis Quirúrgica/métodos , Técnicas de Sutura/normas , Arterias/cirugía , Cuello del Útero/irrigación sanguínea , Femenino , Humanos , Ligadura , Útero/irrigación sanguínea
15.
AJNR Am J Neuroradiol ; 15(10): 1861-9, 1994 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-7863936

RESUMEN

PURPOSE: To measure diagnostic performance and preference of two three-dimensional CT reconstruction modalities (voxel-gradient and surface-projection) displayed two ways (conventional and unwrapped) in craniosynostosis confirmed by surgical inspection and histologic analysis of resected sutures. METHODS: High-resolution 2-mm contiguous CT sections were obtained and three-dimensional reconstruction images generated for 25 infants and children with skull deformities before surgical treatment of craniosynostosis. Two pediatric radiologists and two neuroradiologists first ranked images by their own preferences for diagnostic use. Then they diagnosed craniosynostosis from images presented in random order and blinded. The standard of reference was inspection during surgery and histologic evaluation of excised sutures. Finally, reviewers repeated their subjective preference tests. RESULTS: The least experienced radiologist had 100% sensitivity for all imaging modalities and specificities ranging from 43% to 83%. The two most experienced radiologists performed nearly identically, with sensitivities of 96% and specificities of 100%. After performing diagnostic tasks using all image types, all radiologists preferred conventional surface projections. CONCLUSION: Experienced readers can achieve nearly perfect diagnostic performance using the latest three-dimensional CT reconstruction images, making it a contribution to the diagnostic process. Although performance is nearly identical for all modalities, readers strongly prefer conventionally presented surface-projection images.


Asunto(s)
Craneosinostosis/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador , Tomografía Computarizada por Rayos X/métodos , Algoritmos , Gráficos por Computador , Suturas Craneales/diagnóstico por imagen , Suturas Craneales/patología , Suturas Craneales/cirugía , Craneosinostosis/patología , Craneosinostosis/cirugía , Femenino , Humanos , Lactante , Masculino , Programas Informáticos
16.
Invest Radiol ; 29(10): 890-6, 1994 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-7852040

RESUMEN

RATIONALE AND OBJECTIVES: Two independent gold standards and diagnoses from three-dimensional computed tomography (CT) images were used to examine the possibility that craniosynostosis is a binary abnormality that potentially may be diagnosed without error. METHODS: Surgical reports, histology of excised sutures, and three-dimensional CT images were compared for 25 children undergoing surgical management of craniosynostosis. Surgical reports identified sutures as normal or abnormal. Histology reported suture closure on a 5-point scale. Four radiologists used three-dimensional CT images to diagnose sutures on a 6-point rated response scale. RESULTS: Sutures with histology 0, 1, or 2 were normal on surgical reports, and those with histology 3 or 4 were abnormal. Most readers achieved nearly perfect sensitivity and specificity. Reader confidence was unrelated to degree of pathology. CONCLUSION: Craniosynostosis appears to be binary in our sample. Surgical reports, pathology results, and three-dimensional CT images read by experienced viewers achieved nearly perfect agreement.


Asunto(s)
Craneosinostosis/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Suturas Craneales/anomalías , Suturas Craneales/diagnóstico por imagen , Suturas Craneales/patología , Craneosinostosis/patología , Craneosinostosis/cirugía , Craneotomía , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Lactante , Masculino , Registros Médicos , Variaciones Dependientes del Observador , Hueso Occipital/anomalías , Hueso Occipital/diagnóstico por imagen , Hueso Occipital/patología , Hueso Parietal/anomalías , Hueso Parietal/diagnóstico por imagen , Hueso Parietal/patología , Estudios Prospectivos , Intensificación de Imagen Radiográfica/métodos , Sensibilidad y Especificidad
17.
Pathol Res Pract ; 189(1): 2-17, 1993 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8516213

RESUMEN

Vascular lesions, most often mediated by thrombi, are second only to infections as a cause of fetal injury in the later weeks of pregnancy. In our experience many pathologists who examine placentas fail to conduct a proper search for vascular lesions and some even fail to recognize those exposed by their examination. This review is intended to define the typical clinical background or circumstances that suggest the presence of significant vascular problems, to define techniques calculated to display them well, and to identify criteria for diagnosis. Further research is needed to evaluate the prevalence of maternal and fetal hypercoagulable states and thrombi as a cause of fetal injury.


Asunto(s)
Enfermedades Fetales/patología , Enfermedades Placentarias/patología , Complicaciones Cardiovasculares del Embarazo , Trombosis/patología , Enfermedades Vasculares/patología , Vasos Sanguíneos/anomalías , Vasos Sanguíneos/patología , Femenino , Humanos , Hipertensión/patología , Infarto/patología , Neoplasias/patología , Enfermedades Placentarias/clasificación , Embarazo , Enfermedades Vasculares/clasificación
18.
Am J Obstet Gynecol ; 168(2): 585-91, 1993 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8438933

RESUMEN

OBJECTIVE: Our aim was to find out whether patients delivered preterm because of preterm labor or preterm premature rupture of membranes can be categorized according to clinical characteristics and placental pathologic findings. STUDY DESIGN: We performed a case-control study of 105 patients who were delivered preterm, 42 because of preterm labor and 63 because of premature rupture of membranes, and 105 patients who were delivered at term after uncomplicated pregnancies. RESULTS: Maternal placental vascular lesions were present in 14 (34.1%) patients with preterm labor, 19 (35.1%) patients with premature rupture of membranes, and 9 (11.8%) control patients (odds ratios 3.8 and 4.0, 95% confidence intervals 1.3 to 11.1 and 1.5 to 10.8, p = 0.0065 and 0.0022, respectively). Infection of the products of conception was found in 16 patients (38%) with preterm labor, 23 patients (36.5%) with premature rupture of membranes, and 19 control patients (18%) (odds ratios 2.7 and 2.6, 95% confidence intervals 1.1 to 6.6 and 1.2 to 5.6, p = 0.017 and 0.01, respectively). Patients with maternal placental vasculopathy had significantly different characteristics compared with those of infected patients. CONCLUSIONS: It is possible to identify two subgroups of patients among those who are delivered preterm because of preterm labor or premature rupture of membranes, one with infection of the products of conception and another with maternal placental vasculopathy.


Asunto(s)
Rotura Prematura de Membranas Fetales/etiología , Infecciones/complicaciones , Trabajo de Parto Prematuro/etiología , Enfermedades Placentarias/complicaciones , Placenta/irrigación sanguínea , Enfermedades Vasculares/complicaciones , Estudios de Casos y Controles , Femenino , Humanos , Mortalidad Infantil , Recién Nacido , Infecciones/mortalidad , Infecciones/patología , Enfermedades Placentarias/mortalidad , Enfermedades Placentarias/patología , Embarazo , Enfermedades Vasculares/patología
19.
Am J Surg Pathol ; 16(11): 1085-91, 1992 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-1335210

RESUMEN

Six cases of a distinct, histologically anaplastic variant of mammary Paget's disease are described. Patients ranged in age from 40 to 85 years. All patients had scaling erythematous lesions confined to the nipple; none had palpable breast masses. Histologically, the lesions had features resembling Bowen's disease, including full-thickness epidermal atypia, loss of nuclear polarity, and marked cytologic anaplasia. Intraepidermal acantholysis was a distinctive feature in all cases. In some biopsies, small groups and single typical Pagetoid cells were seen within the areas of confluent Bowen-like change. Immunohistochemically, carcinoembryonic antigen (CEA) was positive in three of six patients; epithelial membrane antigen (EMA) in five of six patients, and cytokeratin AE1/AE3 in three of six patients. Mucicarmine stains were uniformly negative. In our series, anaplastic Paget's disease was associated with concomitant invasive ductal carcinoma in three of six patients (50%). This percentage is significantly higher than that previously reported for patients with Paget's disease and without palpable breast mass. Histologic features that are helpful in distinguishing between anaplastic Paget's disease and Bowen's include cleft-like acantholysis, absence of dyskeratotic cells, and persistence of basal cell layer. More rarely, but very helpful when present, are underlying ductal carcinoma, intracellular lumina, and associated conventional Paget's disease. Immunohistochemistry results were variable and of relative value. Our study suggests that a nipple lesion histologically resembling Bowen's disease is likely to represent anaplastic Paget's disease.


Asunto(s)
Enfermedad de Paget Mamaria/patología , Adulto , Anciano , Enfermedad de Bowen/patología , Diagnóstico Diferencial , Femenino , Histocitoquímica , Humanos , Inmunohistoquímica , Persona de Mediana Edad , Enfermedad de Paget Mamaria/clasificación , Enfermedad de Paget Mamaria/metabolismo , Pronóstico , Factores de Riesgo
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