RESUMEN
Natural selection presumably conserved mechanisms that allow females to block or terminate gestation when environmental circumstances threaten the survival of offspring. One example of this adaptive reproductive suppression, the Bruce effect, has been identified in several species, both in the laboratory and in the wild. Although descriptive epidemiology reports low fertility among women experiencing stressful circumstances, attempts to detect a Bruce effect in humans have been rare and limited. We contribute to this limited work by examining the relationship between the odds of child death and the sex ratio at birth in Sweden for the years 1751-1840. We find evidence of a generalized Bruce effect in humans in that unexpected changes in child mortality predict opposite unexpected changes in the secondary sex ratio in the following year, even after adjusting for period life expectancy. Our analysis broadens the scope of the Bruce effect literature to include humans, suggesting that women, through noncognitive decisional biology, adjust reproductive strategies and investments in response to changing environmental conditions.
Asunto(s)
Mortalidad del Niño , Fertilidad , Razón de Masculinidad , Adulto , Niño , Ambiente , Femenino , Historia del Siglo XVIII , Historia del Siglo XIX , Humanos , Embarazo , Reproducción , SueciaRESUMEN
OBJECTIVES: Human conception cohorts in gestation during stressful times reportedly yield lower ratios of male to female live births than do other conception cohorts. Much literature attributes this phenomenon to spontaneous abortion of less fit male fetuses. Controversy remains, however, as to whether stressful times make males fetuses less fit ("Shifting Distribution" of fitness) or whether male fetuses need greater fitness to avoid spontaneous abortion during stressful times ("Shifting Criterion" for survival). METHODS: Although research using gestational hCG as a signal of fetal fitness reports support for the latter mechanism, we believe an analytic error casts doubt on those findings. Here we offered an alternative test that corrects the error. CONCLUSION: This more accurate test found similar results to those originally reported.
Asunto(s)
Aborto Espontáneo/metabolismo , Gonadotropina Coriónica/sangre , Feto , Modelos Teóricos , Razón de Masculinidad , Estudios de Cohortes , Femenino , Humanos , Masculino , Embarazo , Estrés Psicológico/metabolismoRESUMEN
OBJECTIVES: Antagonists in the debate over whether the maternal stress response during pregnancy damages or culls fetuses have invoked the theory of selection in utero to support opposing positions. We describe how these opposing arguments arise from the same theory and offer a novel test to discriminate between them. Our test, rooted in reports from population endocrinology that human chorionic gonadotropin (hCG) signals fetal fitness, contributes not only to the debate over the fetal origins of illness, but also to the more basic literature concerned with whether and how natural selection in utero affects contemporary human populations. METHODS: We linked maternal serum hCG measurements from prenatal screening tests with data from the California Department of Public Health birth registry for the years 2001-2007. We used time series analysis to test the association between the number of live-born male singletons and median hCG concentration among males in monthly gestational cohorts. RESULTS: Among the 1.56 million gestations in our analysis, we find that median hCG levels among male survivors of monthly conception cohorts rise as the number of male survivors falls. RESULTS: Elevated median hCG among relatively small male birth cohorts supports the theory of selection in utero and suggests that the maternal stress response culls cohorts in gestation by raising the fitness criterion for survival to birth.
Asunto(s)
Aborto Espontáneo/etiología , Gonadotropina Coriónica/sangre , Muerte Fetal/etiología , Selección Genética , Razón de Masculinidad , Aborto Espontáneo/epidemiología , Tasa de Natalidad , California/epidemiología , Estudios de Cohortes , Femenino , Muerte Fetal/epidemiología , Aptitud Genética , Humanos , Mortalidad Infantil/tendencias , Recién Nacido , Nacimiento Vivo , Masculino , Modelos Biológicos , Embarazo , Estrés Fisiológico , Análisis de Supervivencia , Factores de TiempoRESUMEN
Rural hospitals have used numerous strategies over the past several decades to recruit and retain physicians. These have included providing physicians economic incentives, immigration status, professional and technical support and establishing rural training tracks (RTT) in family practice residency programs. This paper presents the experience of an isolated rural region in southwestern New York state that has employed each of these strategies in the past decade. Success as measured by the change in size of the medical staff, hospital operating margins, admissions and employment occurred only after the emphasis changed from meeting hospital needs to physician needs. Pivotal to this strategy was the nurturing and development of an RTT. Investment in the residency program required strong leadership to ensure the political, financial and operational commitment of its affiliated hospital. In addition, the RTT required an affiliation with a financially viable, full-service hospital, a strong on-site chief of service, family physicians who performed cesarean sections, midlevel providers and practitioners dedicated to the mission of teaching.
Asunto(s)
Medicina Familiar y Comunitaria/educación , Hospitales Rurales/organización & administración , Internado y Residencia/organización & administración , Área sin Atención Médica , Modelos Educacionales , Selección de Profesión , Hospitales con 100 a 299 Camas , Hospitales Rurales/estadística & datos numéricos , Humanos , Inversiones en Salud , Liderazgo , New York , Estudios de Casos Organizacionales , Planes de Incentivos para los Médicos , Ubicación de la Práctica Profesional , Evaluación de Programas y Proyectos de Salud , Recursos HumanosRESUMEN
OBJECTIVES: This study sought, first, to explain and reconcile the provocation and inhibition theories of the effect of rising unemployment on the incidence of antisocial behavior. Second, it tested the hypothesis, implied by the provocation and inhibition theories, that the relationship between unemployment and foster home placements forms an inverted "U." METHODS: The hypothesis was tested with data from California for 137 months beginning in February 1984. RESULTS: Findings showed that the hypothesis was supported. CONCLUSIONS: Rising joblessness increases the incidence of foster home placements among families that lose jobs or income. Levels of joblessness that threaten workers who remain employed, however, inhibit antisocial behavior and reduce the incidence of foster home placements. This means that accounting for the social costs of unemployment is more complicated than assumed under the provocation theory.
Asunto(s)
Familia/psicología , Cuidados en el Hogar de Adopción/estadística & datos numéricos , Trastorno de la Conducta Social/psicología , Estrés Psicológico/psicología , Desempleo/psicología , Desempleo/estadística & datos numéricos , Adaptación Psicológica , Adulto , California , Niño , Femenino , Cuidados en el Hogar de Adopción/tendencias , Humanos , Incidencia , Masculino , Prevalencia , Teoría Psicológica , Factores de Riesgo , Estaciones del Año , Trastorno de la Conducta Social/etiología , Trastorno de la Conducta Social/prevención & control , Estrés Psicológico/etiología , Estrés Psicológico/prevención & control , Desempleo/tendenciasRESUMEN
OBJECTIVES: The objective of this study was to test the hypothesis that unexpectedly high unemployment in a community is associated with reduced odds that registered breast tumors are local. METHODS: The hypothesis was tested with data from San Francisco for the 132 months beginning with January 1983. RESULTS: Registered breast tumors were less likely to be local during periods of unexpectedly high unemployment (8% less likely among non-Hispanic White women and 24% less likely among African-American women). CONCLUSIONS: Job loss may restrict access to health services. Fear of job loss may also distract women from breast self-examination and the identification of suspicious breast signs.
Asunto(s)
Neoplasias de la Mama/epidemiología , Neoplasias de la Mama/prevención & control , Desempleo/estadística & datos numéricos , Mujeres Trabajadoras/estadística & datos numéricos , Negro o Afroamericano/estadística & datos numéricos , Neoplasias de la Mama/patología , Miedo , Femenino , Accesibilidad a los Servicios de Salud , Humanos , Estadificación de Neoplasias , Oportunidad Relativa , Programa de VERF , San Francisco/epidemiología , Desempleo/tendencias , Población Blanca/estadística & datos numéricosRESUMEN
Persons believed to be mentally ill and imminently violent are often subjected to coerced treatment. Among the justifications for this practice is the argument that removing such people from the community is analogous to quarantine. We test the quarantine theory using daily data from San Francisco. Results suggest that the incidence of coerced treatment of males is inversely related to assaults and batteries by males one day later. The finding implies that persons who are involuntarily committed are at elevated risk of violent behavior. The implications of the findings for the prevention of assaultive behavior are briefly described.
Asunto(s)
Internamiento Obligatorio del Enfermo Mental , Violencia/prevención & control , Algoritmos , Coerción , Femenino , Humanos , Masculino , Factores de Riesgo , San Francisco , Factores de Tiempo , Violencia/estadística & datos numéricosRESUMEN
Because of serious side effects, the indications for intralesional steroid injection of adnexal hemangiomas are unclear. Of 23 children with such lesions who were examined over a period of 9 years, 9 had no evidence of amblyopia and needed no intervention. Five required steroids intralesionally and/or systemically because of threatened occlusion of the pupillary axis. The remaining 9 were considered at risk of anisometropic amblyopia because of induced astigmatism: 5 received injections and 4 were treated with glasses and/or patching alone. The visual, refractive, and cosmetic results of the injected and conservatively managed anisometropes were similar. We recommend that steroid injection be reserved for patients with threatened occlusion of the visual axis and for those with severe astigmatism or amblyopia refractory to conservative management.
Asunto(s)
Ambliopía/terapia , Anisometropía/terapia , Betametasona/uso terapéutico , Neoplasias de los Párpados/tratamiento farmacológico , Hemangioma Capilar/tratamiento farmacológico , Triamcinolona/uso terapéutico , Ambliopía/etiología , Anisometropía/etiología , Quimioterapia Combinada , Anteojos , Neoplasias de los Párpados/complicaciones , Hemangioma Capilar/complicaciones , Humanos , Lactante , Inyecciones Intralesiones , Refracción Ocular , Privación Sensorial , Agudeza VisualRESUMEN
A disproportionate share of ocular and orbital injuries occur in children. This article reviews the evaluation and initial management of ocular trauma and chemical burns to the eye. Traumatic conditions are classified according to the particular area of the eye or orbit involved; chemical burns constitute a separate section. Sports-related injuries and their prevention are emphasized.
Asunto(s)
Lesiones Oculares/prevención & control , Traumatismos en Atletas/prevención & control , Quemaduras Químicas/terapia , Niño , Quemaduras Oculares/inducido químicamente , Quemaduras Oculares/terapia , Lesiones Oculares/diagnóstico , Lesiones Oculares/terapia , Humanos , MasculinoRESUMEN
We examined 30 infants in whom cortical visual impairment was diagnosed during their first year of life to ascertain prognostic factors for the development of object vision, defined as the ability to recognize faces or hand-held toys. All patients were followed up for a minimum of 12 months. The most common causes of cortical visual impairment in the 30 infants were hydrocephalus in nine infants (30.0%), birth asphyxia or neonatal hypoxia in eight infants (26.7%), intracranial hemorrhage with or without hydrocephalus in seven infants (23.3%), and meningitis in five infants (16.7%). Lack of development of object vision was associated only with hypoxia (P = .013). Findings on ophthalmic examination, an abnormality in the visual pathway on computed tomographic or magnetic resonance scan, and seizures, hydrocephalus, intracranial hemorrhage, meningitis, cerebral palsy, developmental delay, prematurity, microcephaly, and hearing deficit, did not appear to be risk factors for the lack of development of object vision.
Asunto(s)
Percepción de Forma/fisiología , Trastornos de la Visión/fisiopatología , Corteza Visual/fisiopatología , Encefalopatías/complicaciones , Encefalopatías/fisiopatología , Femenino , Estudios de Seguimiento , Humanos , Lactante , Masculino , Pronóstico , Factores de Riesgo , Trastornos de la Visión/etiologíaRESUMEN
Glaucoma after pediatric cataract surgery, once well recognized, now occurs only rarely after modern lensectomy/vitrectomy. The authors performed directed glaucoma evaluations of 34 eyes of 26 children. Based on intraocular pressures of 26 mmHg or greater, glaucoma was diagnosed in 8 (24%) eyes of 7 (27%) children. Glaucoma was found more commonly among children followed more than 60 months and was diagnosed up to 105 months after surgery. Typically, the glaucoma was open angle and asymptomatic. Four children had had previously normal pressures recorded. With longer follow-up, it is likely that more children will be diagnosed with glaucoma after lensectomy/vitrectomy procedures. The authors believe such patients should be followed as glaucoma suspects for the rest of their lives.
Asunto(s)
Extracción de Catarata/efectos adversos , Glaucoma de Ángulo Abierto/etiología , Vitrectomía/efectos adversos , Niño , Preescolar , Estudios de Seguimiento , Glaucoma de Ángulo Abierto/diagnóstico , Humanos , Lactante , Recién Nacido , Presión Intraocular , Campos VisualesRESUMEN
We treated seven patients with unilateral oculomotor nerve palsy by transposition of the insertion of the superior oblique tendon to a point anterior and medial to the insertion of the superior rectus muscle without trochleotomy (Scott procedure). Additionally, large recessions of the lateral rectus muscle of involved eyes and, occasionally, recess/resect procedures of horizontal recti muscles of non-involved eyes were performed. All patients were followed up between one and eight years. Orthophoria in the primary position was achieved and maintained with one operation in four patients. A fifth patient had only a small residual exotropia. In two patients who had aberrant regeneration of the oculomotor nerve, surgery on horizontal recti muscles of the noninvolved eye improved the eyelid position of the involved eye after three operations.
Asunto(s)
Enfermedades del Nervio Oculomotor/cirugía , Blefaroptosis/cirugía , Niño , Exotropía/cirugía , Párpados/cirugía , Estudios de Seguimiento , Humanos , Regeneración Nerviosa , Músculos Oculomotores/cirugía , PronósticoRESUMEN
Clinical findings as well as eye and head movement recordings were analyzed from 23 patients with spasmus nutans without central nervous system (CNS) changes, 10 patients with spasmus nutans-like disease (head nodding, intermittent nystagmus associated with intracranial anomalies or visual pathway disorders), and 25 patients with infantile nystagmus. Ten diagnostic signs were established to differentiate between the patient groups. Although they were helpful in separating patients with infantile nystagmus from those with spasmus nutans, no difference was found between the patients with spasmus nutans with and without CNS lesions. This study indicates that eye and head movement recordings do not allow differentiation between benign spasmus nutans and spasmus nutans-like disease. The differentiation must be made on the basis of neuroimaging.
Asunto(s)
Nistagmo Patológico/diagnóstico , Espasmos Infantiles/diagnóstico , Niño , Preescolar , Diagnóstico Diferencial , Movimientos Oculares , Femenino , Cabeza , Humanos , Lactante , Masculino , PosturaRESUMEN
Five children (three girls and two boys, aged 3 1/2 to 9 1/2 years) were referred by their pediatricians for evaluation of intermittent pulling on their eyelids. All the children were free of systemic disease. One child wore spectacles for accommodative esotropia but no child had evidence of an acute ocular disorder. The duration of symptoms before examination ranged from one to 13 months. None of the parents were able to identify temporally related stressful events. Reassurance alone was given to both parents and children; eyelid pulling resolved in all cases within two weeks. In only the youngest patient did eyelid pulling recur and no child developed other symptoms during a follow-up of six to 15 months. Following resolution, parents believed their children pulled on the eyelids to gain attention or because their eyes were initially irritated and they then developed a "bad habit." Children said they did it to "look funny" or because their "eyes were not opening enough."
Asunto(s)
Conducta Infantil , Párpados , Atención , Actitud Frente a la Salud , Niño , Preescolar , Femenino , Humanos , Masculino , PadresRESUMEN
Of five children who had Down's syndrome with optic nerve head elevation, without associated intracranial lesions, three underwent enhanced computed tomography for which no abnormalities were found. Partial, complete, or intermittent resolution of the optic disk elevation occurred in three children. In none of the children were retinal vessel dilation, splinter hemorrhages, optic nerve drusen, subsequent optic atrophy, or apparent visual loss noted. All of the children were hyperopic, but only one child had a hyperopia of greater than 3.50 diopters.