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1.
Psychol Med ; 53(12): 5428-5441, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-35879886

RESUMEN

BACKGROUND: The impact of the coronavirus disease 2019 (COVID-19) pandemic on mental health is still being unravelled. It is important to identify which individuals are at greatest risk of worsening symptoms. This study aimed to examine changes in depression, anxiety and post-traumatic stress disorder (PTSD) symptoms using prospective and retrospective symptom change assessments, and to find and examine the effect of key risk factors. METHOD: Online questionnaires were administered to 34 465 individuals (aged 16 years or above) in April/May 2020 in the UK, recruited from existing cohorts or via social media. Around one-third (n = 12 718) of included participants had prior diagnoses of depression or anxiety and had completed pre-pandemic mental health assessments (between September 2018 and February 2020), allowing prospective investigation of symptom change. RESULTS: Prospective symptom analyses showed small decreases in depression (PHQ-9: -0.43 points) and anxiety [generalised anxiety disorder scale - 7 items (GAD)-7: -0.33 points] and increases in PTSD (PCL-6: 0.22 points). Conversely, retrospective symptom analyses demonstrated significant large increases (PHQ-9: 2.40; GAD-7 = 1.97), with 55% reported worsening mental health since the beginning of the pandemic on a global change rating. Across both prospective and retrospective measures of symptom change, worsening depression, anxiety and PTSD symptoms were associated with prior mental health diagnoses, female gender, young age and unemployed/student status. CONCLUSIONS: We highlight the effect of prior mental health diagnoses on worsening mental health during the pandemic and confirm previously reported sociodemographic risk factors. Discrepancies between prospective and retrospective measures of changes in mental health may be related to recall bias-related underestimation of prior symptom severity.


Asunto(s)
COVID-19 , Trastornos por Estrés Postraumático , Femenino , Humanos , Trastornos por Estrés Postraumático/epidemiología , Trastornos por Estrés Postraumático/psicología , COVID-19/epidemiología , Pandemias , Depresión/psicología , Estudios Retrospectivos , Estudios Prospectivos , SARS-CoV-2 , Ansiedad/psicología , Reino Unido/epidemiología
2.
MRS Adv ; 5(56): 2853-2861, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33437530

RESUMEN

We demonstrate a methodology for predicting particle removal efficiency of polypropylene-based filters used in personal protective equipment, based on quantification of disorder in the context of methyl group orientation as structural motifs in conjunction with an Ising model. The corresponding Bragg-Williams order parameter is extracted through either Raman spectro-scopy or scanning electron microscopy. Temperature-dependent analysis verifies the presence of an order-disorder transition, and the methodology is applied to published data for multiple samples. The result is a method for predicting the particle removal efficiency of filters used in masks based on a material-level property.

3.
Cell Prolif ; 50(2)2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27976431

RESUMEN

OBJECTIVES: Adipose tissue plays a fundamental role in glucose homeostasis. For example, fat removal (lipectomy, LipX) in lean mice, resulting in a compensatory 50% increase in total fat mass, is associated with significant improvement in glucose tolerance. This study was designed to further examine the link between fat removal, adipose tissue compensation and glucose homeostasis using a peroxisome proliferator-activated receptor γ (PPAR γ; activator of adipogenesis) knockout mouse. MATERIAL AND METHODS: The study involved PPARγ knockout (FKOγ) or control mice (CON), subdivided into groups that received LipX or Sham surgery. We reasoned that as the ability of adipose tissue to expand in response to LipX would be compromised in FKOγ mice, so would improvements in glucose homeostasis. RESULTS: In CON mice, LipX increased total adipose depot mass (~60%), adipocyte number (~45%) and changed adipocyte distribution to smaller cells. Glucose tolerance was improved (~30%) in LipX CON mice compared to Shams. In FKOγ mice, LipX did not result in any significant changes in adipose depot mass, adipocyte number or distribution. LipX FKOγ mice were also characterized by reduction of glucose tolerance (~30%) compared to shams. CONCLUSIONS: Inhibition of adipose tissue PPARγ prevented LipX-induced increases in adipocyte expansion and produced a glucose-intolerant phenotype. These data support the notion that adipose tissue expansion is critical to maintain and/or improvement in glucose homeostasis.


Asunto(s)
Adipocitos/citología , Adipogénesis , Glucosa/farmacología , Lipectomía , Obesidad/metabolismo , PPAR gamma/metabolismo , Adipocitos/metabolismo , Adipogénesis/fisiología , Tejido Adiposo/metabolismo , Animales , Femenino , Glucosa/metabolismo , Intolerancia a la Glucosa , Lipectomía/métodos , Metabolismo de los Lípidos/fisiología , Masculino , Ratones , Ratones Transgénicos , PPAR gamma/genética
4.
S Afr Med J ; 107(1): 83-88, 2016 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-28112098

RESUMEN

BACKGROUND: Excessive sun exposure and a high prevalence of HIV increase skin cancer risk in South Africa (SA). OBJECTIVE: To describe the nature and extent of skin cancers presenting in the public and private health sectors of the Northern Cape Province of SA. METHODS: A retrospective analysis of histologically confirmed new primary cutaneous malignancies from 1 January 2008 to 31 December 2012 was conducted using public and private health sector databases. Types, quantity and distribution of common invasive malignancies by population group, age, gender, anatomical site and health sector were explored. One-year cumulative incidence was calculated and logistic regression models were used to analyse incidence and melanoma thickness trends. RESULTS: A total of 4 270 biopsies (13 cutaneous malignancies) were identified. The commonest was squamous cell carcinoma (SCC), followed by basal cell carcinoma, Kaposi's sarcoma (KS), cutaneous malignant melanoma (CMM) and basosquamous carcinoma, in descending order. The odds of a white male developing SCC increased by 8% each year (odds ratio (OR) 1.08, 95% confidence interval (CI) 1.01 - 1.15; p=0.022), while the odds of a black male developing SCC and KS decreased by 9% (OR 0.91, 95% CI 0.84 - 0.99; p=0.033) and 18% (OR 0.82, 95% CI 0.70 - 0.97; p=0.022), respectively, each year. SCC and CMM were diagnosed at more advanced stages in the public than in the private healthcare sector. CMM is being detected earlier, as indicated by low-stage depth increasing by 72% annually (OR 1.72, 95% CI 1.04 - 3.01; p=0.042). CONCLUSIONS: Results suggest that reported skin cancer patterns are changing. There is a need for further research and equitable appropriation of financial resources and effort towards developing primary skin cancer prevention initiatives in SA.

5.
Adipocyte ; 4(1): 32-43, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26167400

RESUMEN

It has been postulated that the protective effects of lower body subcutaneous adipose tissue (LBSAT) occur via its ability to sequester surplus lipid and thus serve as a "metabolic sink." However, the mechanisms that mediate this protective function are unknown thus this study addresses this postulate. Ad libitum, chow-fed mice underwent Sham-surgery or LBSAT removal (IngX, inguinal depot removal) and were subsequently provided chow (Chow; typical adipocyte expansion) or high fat diet (HFD; enhanced adipocyte expansion) for 5 weeks. Primary outcome measures included glucose tolerance and subsequent insulin response, muscle insulin sensitivity, liver and muscle triglycerides, adipose tissue gene expression, and circulating lipids and adipokines. In a follow up study the consequences of extended experiment length post-surgery (13 wks) or pre-existing glucose intolerance were examined. At 5 wks post-surgery IngX in HFD-fed mice reduced glucose tolerance and muscle insulin sensitivity and increased circulating insulin compared with HFD Sham. In Chow-fed mice, muscle insulin sensitivity was the only measurement reduced following IngX. At 13 wks circulating insulin concentration of HFD IngX mice continued to be higher than HFD Sham. Surgery did not induce changes in mice with pre-existing glucose intolerance. IngX also increased muscle, but not liver, triglyceride concentration in Chow- and HFD-fed mice 5 wks post-surgery, but chow group only at 13 wks. These data suggest that the presence of LBSAT protects against triglyceride accumulation in the muscle and HFD-induced glucose intolerance and muscle insulin resistance. These data suggest that lower body subcutaneous adipose tissue can function as a "metabolic sink."

6.
Adipocyte ; 4(2): 101-12, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26167414

RESUMEN

Visceral adiposity is associated with type-2-diabetes, inflammation, dyslipidemia and non-alcoholic fatty liver disease (NAFLD), whereas subcutaneous adiposity is not. We hypothesized that the link between visceral adiposity and liver pathophysiology involves inherent or diet-derived differences between visceral and subcutaneous adipose tissue to store and mobilize saturated fatty acids. The goal of the present study was to characterize the fatty acid composition of adipose tissue triglyceride and portal vein fatty acids in relation to indices of liver dysregulation. For 8 weeks rats had free access to control (CON; 12.9% corn/safflower oil; 3.6 Kcal/g), high saturated fat (SAT; 45.2% cocoa butter; 4.5 Kcal/g) or high polyunsaturated fat (PUFA; 45.2% safflower oil; 4.5 Kcal/g) diets. Outcome measures included glucose tolerance, visceral and subcutaneous adipose tissue triglyceride, liver phospholipids and plasma (portal and systemic) free fatty acid composition, indices of inflammation and endoplasmic reticulum stress in the liver and adipose tissue depots and circulating adipo/cytokines. Hepatic triglycerides were significantly increased in both high fat diet groups compared to control and were significantly higher in PUFA compared to SAT. Although glucose tolerance was not different among diet groups, SAT increased markers of inflammation and ER stress in the liver and both adipose tissue depots. Fatty acid composition did not differ among adipose depots or portal blood in any dietary group. Overall, these data suggest that diets enriched in saturated fatty acids are associated with liver inflammation, ER stress and injury, but that any link between visceral adipose tissue and these liver indices does not involve selective changes to fatty acid composition in this depot or the portal vein.

7.
Mayo Clin Proc ; 74(8): 770-4, 1999 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10473352

RESUMEN

OBJECTIVE: To compare self-perception between a group of competitive, elite female collegiate athletes (participating in gymnastics, cross country, and track and field) and a group of female political science students (nonathletic control subjects). We hypothesized that the athletic group would rate athletics as more important than would the nonathletic group, that the perception of athletic competence would correlate positively with self-worth for athletes only, and that the perception of athletic competence would have a stronger influence on self-worth in the athletic group. SUBJECTS AND METHODS: The Self-perception Profile for College Students was completed by 32 athletes and 13 nonathletes. This profile measures 12 subscales plus Global Self-worth independently and generates scores that reflect the subject's perceived importance of and competence in each of the subscale areas. RESULTS: The athletes rated athletics as more important than did nonathletes, although this trend was nonsignificant when adjusted for age. As age increased, the importance of athletics decreased for both groups. There was a direct relationship between perceived athletic competence and self-worth for the athletes but not for the nonathletes. Variables that accounted for the Global Self-worth score in athletes were perceptions of Competence subscales for Appearance, Social Acceptance, Friendship, and Job. Variables that accounted for the Global Self-worth scores in the nonathletes were perceptions of Competence subscales for Romance, Morality, Humor, and Appearance. The athletic group had significantly lower Global Self-worth scores than the nonathletic group. CONCLUSIONS: The female athletes in this study derived a large component of their self-worth from their perceived athletic competence. Clinicians should bear in mind the relative importance of athletics to young female athletes and the relationship of perceived athletic ability to self-worth when treating these individuals.


Asunto(s)
Gimnasia/psicología , Carrera/psicología , Autoimagen , Estudiantes/psicología , Atletismo/psicología , Adulto , Femenino , Humanos , Pruebas Psicológicas
8.
Arch Ophthalmol ; 104(1): 87-9, 1986 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-3510613

RESUMEN

We performed a retrospective analysis of the clinical and pathologic diagnoses of 497 corneal buttons that had been submitted to the Estelle Doheny Eye Pathology Laboratory, Los Angeles, during the five-year period 1979 through 1983. The leading indications, in order of decreasing frequency, were pseudophakic bullous keratopathy (17.5%), regrafts (15.1%), aphakic bullous keratopathy (10.9%), corneal trauma (9.3%), and Fuchs' endothelial dystrophy (9.1%). The emergence of pseudophakic bullous keratopathy as the most common cause for penetrating keratoplasty correlates well with the dramatic increase in the number of cataract extractions with intraocular lens implantations performed since the mid-1970s. Less frequent indications for penetrating keratoplasty included the following: corneal scars (6%); active ulcerative keratitis (7%); keratoconus (6%); keratitis secondary to virus (5%); non-Fuchs' corneal dystrophies (3%); congenital corneal opacities (3%); interstitial keratitis (2%); and chemical burns (1%).


Asunto(s)
Córnea/cirugía , Oftalmología/tendencias , Adolescente , Adulto , Anciano , Extracción de Catarata/efectos adversos , Niño , Preescolar , Enfermedades de la Córnea/cirugía , Trasplante de Córnea , Femenino , Humanos , Lactante , Recién Nacido , Queratocono/cirugía , Lentes Intraoculares/efectos adversos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/cirugía
9.
J Pers Soc Psychol ; 63(3): 494-508, 1992 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-1403628

RESUMEN

In an analysis of adult personality structure, types are defined as prototypes rather than as discrete categories. Using inverse factor analyses of archival Q-sort descriptions, 4 type factors were replicated in a cross-validation design. These prototypes are interpreted as Individuated, Traditional, Conflicted, and Assured and are related to Rank's (1945) theoretical analysis of different modes of adjustment. These prototypes capture particular combinations of personality dimensions, such as Ego Resiliency, Ego Control, and the Big Five, and converge with the types identified by Block (1971). Further analyses using 13 clusters of scales from 3 broad-band self-report inventories validated the Q-sort-based interpretations and showed a distinct and theoretically consistent patterning for each of the types.


Asunto(s)
Identidad de Género , Desarrollo de la Personalidad , Q-Sort/estadística & datos numéricos , Adulto , Estudios de Cohortes , Ego , Análisis Factorial , Femenino , Humanos , Control Interno-Externo , Estudios Longitudinales , Persona de Mediana Edad , Psicometría , Ajuste Social
10.
Arch Dermatol Res ; 274(1-2): 1-8, 1982.
Artículo en Inglés | MEDLINE | ID: mdl-6219633

RESUMEN

There is considerable evidence to suggest that autoimmunity plays a role in the pathogenesis of alopecia areata. Since it is known that T cells regulate the immune system, a study was undertaken to measure T helper (OKT-4) and T suppressor (OKT-8) cells in the peripheral blood of patients with alopecia areata (both active and stable) and in controls. Total T cells, B cells, immunoglobulins, and autoantibodies were also measured. There was a highly significant decrease in the T-suppressor cell population of patients with alopecia areata (P less than 0.001). Two of ten patients had microsomal antibodies and three of ten had elevated IgE levels. Other parameters were not significantly different. The decrease in suppressor cells suggest an impairment of the prime negative regulator of the immune system, with loss of tolerance and resultant autoimmunity.


Asunto(s)
Alopecia Areata/inmunología , Linfocitos T Reguladores/inmunología , Adolescente , Adulto , Enfermedades Autoinmunes/inmunología , Femenino , Humanos , Recuento de Leucocitos , Masculino , Persona de Mediana Edad , Linfocitos T Colaboradores-Inductores/inmunología
11.
Cornea ; 4(1): 51-7, 1985.
Artículo en Inglés | MEDLINE | ID: mdl-4092480

RESUMEN

Two containers ("Iowa" and "Virginia") commonly used for transporting donor corneas, and various packing methods were evaluated for constancy of temperature maintenance. The larger Iowa container was found to be superior for extended storage. Packing methods that allowed the vials (containing McCarey-Kaufman medium) to be in direct contact with wet ice or with ice water resulted in the best cooling. Direct contact with supercooled ice may cause freezing of the medium. Separating the vials from the ice water slush by dry foam rubber or Styrofoam did not allow adequate cooling. Heat sealing the vials in a plastic bag containing minimal air permitted proper cooling and may reduce the risk of contamination from the ice water.


Asunto(s)
Bancos de Ojos/métodos , Temperatura , Bancos de Tejidos/métodos , Transportes/métodos , Equipos y Suministros , Humanos , Hielo , Poliestirenos , Goma
12.
Nurs Clin North Am ; 22(4): 805-14, 1987 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-3120154

RESUMEN

This article describes the contribution of the lungs to the regulation of acid-base balance with a focus on clinical implications. The interpretation of arterial blood gas results is described, and nursing interventions to address acid-base imbalances are discussed. A case study illustrates acid-base imbalances in chronic obstructive lung disease.


Asunto(s)
Desequilibrio Ácido-Base/fisiopatología , Pulmón/fisiopatología , Desequilibrio Hidroelectrolítico/fisiopatología , Acidosis Respiratoria/fisiopatología , Alcalosis Respiratoria/fisiopatología , Bicarbonatos/sangre , Dióxido de Carbono/sangre , Humanos , Riñón/metabolismo , Enfermedades Pulmonares Obstructivas/fisiopatología , Oxígeno/sangre
13.
Nurs Clin North Am ; 20(4): 657-67, 1985 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-3852297

RESUMEN

A model for clinical validation of the respiratory nursing diagnoses of ineffective airway clearance and ineffective breathing pattern is presented. The study showed that critical defining characteristics are associated with and differentiate each respiratory nursing diagnosis. The methodology used can be easily incorporated into regular clinical activities in many settings.


Asunto(s)
Modelos Teóricos , Evaluación en Enfermería/normas , Proceso de Enfermería/normas , Enfermedades Respiratorias/enfermería , Estudios de Evaluación como Asunto , Humanos , Entrevistas como Asunto , Planificación de Atención al Paciente , Pruebas de Función Respiratoria , Enfermedades Respiratorias/clasificación , Enfermedades Respiratorias/fisiopatología , Encuestas y Cuestionarios
14.
J Med Imaging Radiat Oncol ; 54(5): 431-4, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20958941

RESUMEN

INTRODUCTION: Brain computed tomography (CT) is inconsistently recommended worldwide in the investigative algorithm of patients presenting with first episode psychosis (FEP). The objective of this study is to investigate the clinical efficacy of brain CT in patients presenting with FEP without neurological signs in a major metropolitan teaching hospital. METHODS: The CT brain scan reports of 237 consecutive patients, for which the imaging requests or reports provided a history of FEP but no focal neurological signs, were retrospectively identified within a 6-year period in a 750-bed tertiary referral teaching hospital using the radiology information system text-search function (170 male, 67 female; mean age, 28.3 years). All reports were authored or approved by consultant radiologist. They were reviewed for the presence of any lesion that could cause psychosis and hence alter clinical management. Minor neuroradiological abnormalities were also noted. Hospital Ethics Committee registration and approval were obtained and patient informed consent was not required. RESULTS: No focal brain lesion potentially responsible for the psychosis or focal lesion requiring surgical intervention was identified in any patient. Findings unable to be directly linked to the psychosis such as evidence of small vessel ischaemic disease, arachnoid cysts, cerebral atrophy, and normal variants were present in 17.6% of patients (45 of 237 studies), none of which led to an alteration of clinical management. CONCLUSION: The results of this study postulate that brain CT should not be universally performed in the initial assessment of patients with first episode psychosis without neurological signs.


Asunto(s)
Encéfalo/diagnóstico por imagen , Trastornos Psicóticos/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Adolescente , Adulto , Anciano , Daño Encefálico Crónico/diagnóstico por imagen , Diagnóstico Diferencial , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos
15.
AORN J ; 49(5): 1308-10, 1312-4, 1316-7 passim, 1989 May.
Artículo en Inglés | MEDLINE | ID: mdl-2658799
16.
Heart ; 95(23): 1901-6, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19666461

RESUMEN

OBJECTIVE: This study investigated the relation between psychotropic medication use and adverse cardiovascular (CV) events in women with symptoms of myocardial ischaemia undergoing coronary angiography. METHOD: Women enrolled in the Women's Ischemia Syndrome Evaluation (WISE) were classified into one of four groups according to their reported antidepressant and anxiolytic medication usage at study intake: (1) no medication (n = 352); (2) anxiolytics only (n = 67); (3) antidepressants only (n = 58); and (4) combined antidepressant and anxiolytics (n = 39). Participants were followed prospectively for the development of adverse CV events (for example, hospitalisations for non-fatal myocardial infarction, stroke, congestive heart failure and unstable angina) or all-cause mortality over a median of 5.9 years. RESULTS: Use of antidepressant medication was associated with subsequent CV events (HR 2.16, 95% CI 1.21 to 3.93) and death (HR 2.15, 95% CI 1.16 to 3.98) but baseline anxiolytic use alone did not predict subsequent CV events and death. In a final regression model that included demographics, depression and anxiety symptoms, and risk factors for cardiovascular disease, women in the combined medication group (that is, antidepressants and anxiolytics) had higher risk for CV events (HR 3.98, CI 1.74 to 9.10, p = 0.001 and all-cause mortality (HR 4.70, CI 1.7 to 2.97, p = 0.003) compared to those using neither medication. Kaplan-Meier survival curves indicated that there was a significant difference in mortality among the four medication groups (p = 0.001). CONCLUSIONS: These data suggest that factors related to psychotropic medication such as depression refractory to treatment, or medication use itself, are associated with adverse CV events in women with suspected myocardial ischaemia.


Asunto(s)
Ansiolíticos/efectos adversos , Antidepresivos/efectos adversos , Trastorno Depresivo/tratamiento farmacológico , Isquemia Miocárdica/inducido químicamente , Adolescente , Adulto , Anciano , Causas de Muerte , Angiografía Coronaria , Trastorno Depresivo/mortalidad , Supervivencia sin Enfermedad , Femenino , Humanos , Estimación de Kaplan-Meier , Persona de Mediana Edad , Isquemia Miocárdica/diagnóstico por imagen , Isquemia Miocárdica/mortalidad , Factores de Riesgo , Adulto Joven
17.
J Exp Child Psychol ; 38(3): 464-74, 1984 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-6520584

RESUMEN

Across three studies, conditions were varied under which children aged 4-5 years matched the area of a rectangle with a given width (or height) to that of a square. In the first study, subjects observed the rectangle being changed in height from trial to trial and had access to their immediately preceding response. Under these conditions, rectangle width (the dimension under subject control) was a linear decreasing function of rectangle height. This function was interpreted as evidence for a hypothetical addition/subtraction strategy for maintaining equality in area between the comparison rectangle and the standard square. As a test of this hypothesis, in a second experiment the subjects were denied access to their immediately previous response, and in a third study they were also unable to observe the rectangle as it was altered by the experimenter between trials. The purpose of these changes was to remove the information necessary for readily implementing an addition/subtraction strategy. In both studies, area matches seemed to be based on a side-matching strategy, such that subjects matched one dimension of the rectangle to one side of the standard square. It was suggested that young children use different cues or strategies with different variants of the matching task because they do not possess a fixed, specific concept of area.


Asunto(s)
Aprendizaje Discriminativo , Percepción de Forma , Percepción del Tamaño , Atención , Preescolar , Formación de Concepto , Señales (Psicología) , Femenino , Humanos , Masculino
18.
J Ocul Pharmacol ; 4(4): 351-8, 1988.
Artículo en Inglés | MEDLINE | ID: mdl-3246570

RESUMEN

Polyvinylpyrrolidone-iodine (PVP-I) is a biocompatible broad spectrum antimicrobial that is widely used as an ophthalmic pre-operative prepping agent. In order to determine if PVP-I is safe for treating corneal ulcers and conjunctivitis, we evaluated the ocular toxicity of frequent dosing in a rabbit model. We evaluated ocular irritation in 18 rabbits according to the McDonald-Shadduck method. Concentrations of 0.5% PVP-I or less were practically non-irritating when administered six times per day. We evaluated corneal epithelial wound healing in 16 rabbits with standardized abrasions. Concentrations of 0.33% PVP-I showed epithelial healing comparable to gentamicin treated eyes and untreated controls. Concentrations of 0.5% PVP-I delayed epithelial healing by one day. Because of its broad spectrum and apparently low toxicity, PVP-I may be a useful treatment for corneal ulcers, keratitis and conjunctivitis.


Asunto(s)
Córnea/efectos de los fármacos , Povidona Yodada/toxicidad , Povidona/análogos & derivados , Animales , Conjuntiva/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Epitelio/efectos de los fármacos , Gentamicinas/uso terapéutico , Conejos , Factores de Tiempo , Cicatrización de Heridas/efectos de los fármacos
19.
Proc Natl Acad Sci U S A ; 86(23): 9109-13, 1989 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-2512576

RESUMEN

The construction of allele-specific suppressor mutations has enabled us to demonstrate that a sporulation-specific transcription unit in Bacillus subtilis, the spoIIG operon, is transcribed by a form of RNA polymerase associated with sigma A, the principal sigma factor in vegetative cells. The spoIIG operon encodes sporulation-specific factor sigma E, and its transcription is directed from a promoter that is activated about 1 hr after the onset of endospore formation. This promoter contains sequences that are similar to those found at the -10 and -35 regions of promoters that are used by sigma A-associated RNA polymerase, but these sigma A-like recognition sequences are separated by 22 base pairs rather than the typical 17 or 18 base pairs. We have found that substitution of an arginyl residue for the glutamyl residue at position 196 of sigma A (Glu-196----Arg) suppresses the deleterious effect of a thymidine-to-cytidine base substitution at position -11 in the spoIIG promoter. This suppression was allele-specific, since it did not suppress the effects of base substitutions in other positions in the spoIIG promoter or the effects of a thymidine-to-guanosine change at -11. These results support a model in which a form of RNA polymerase containing sigma A is utilized in an unusual manner to activate the transcription of the spoIIG operon well after the onset of endospore formation.


Asunto(s)
Bacillus subtilis/genética , ARN Polimerasas Dirigidas por ADN/metabolismo , Regiones Promotoras Genéticas , Factor Rho/metabolismo , Factores de Transcripción/metabolismo , Alelos , Bacillus subtilis/enzimología , Bacillus subtilis/fisiología , Secuencia de Bases , Expresión Génica , Datos de Secuencia Molecular , Mutación , Sondas de Oligonucleótidos , Operón , Esporas Bacterianas/fisiología , Supresión Genética , Transcripción Genética
20.
J Bacteriol ; 174(8): 2648-58, 1992 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-1556084

RESUMEN

The spoIIE operon is a developmentally regulated transcription unit activated in the second hour of sporulation in Bacillus subtilis. Its promoter has an unusual structure, containing sequences which conform perfectly to the consensus for vegetative promoters recognized by sigma A-associated RNA polymerase (E sigma A), but with a spacing of 21 bp between the apparent -10 and -35 elements instead of the 17- or 18-bp spacing typical of promoters utilized by E sigma A. Mutations introduced into the apparent -10 element affected transcription in a manner consistent with its functioning as a polymerase recognition sequence. The deleterious effect of one -10 mutation was also suppressed in an allele-specific manner by a mutation in sigA known to suppress analogous -10 mutations in conventional vegetative promoters recognized by E sigma A. Similar suppression experiments failed to provide evidence for a direct interaction between E sigma A and the "-35-like" element, however, and DNase I protection experiments suggested instead that the Spo0A protein binds to a site overlapping this -35-like hexamer. Moreover, the effects of mutations within the -35-like hexamer on the binding of Spo0A in vitro paralleled their effects on transcription in vivo. We suggest that spoIIE belongs to a class of early-intermediate sporulation genes whose transcription by E sigma A is activated by the Spo0A protein.


Asunto(s)
Bacillus subtilis/genética , Regulación Bacteriana de la Expresión Génica , Factor sigma/genética , Secuencia de Bases , ADN Bacteriano/genética , Genes Bacterianos , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Oligodesoxirribonucleótidos/química , Operón , Regiones Promotoras Genéticas , Secuencias Reguladoras de Ácidos Nucleicos , Esporas Bacterianas , Factores de Tiempo , Transcripción Genética
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