RESUMO
Balanced (1 to 1) sex ratios are thought to evolve by a process known as frequency- dependent selection of the minority sex. Five populations of a fish with genetically based variation in temperature-dependent sex determination were maintained for 5 to 6 years in artificial constant-temperature environments that initially caused the sex ratio to be highly skewed. Increases in the proportion of the minority sex occurred in subsequent generations until a balanced sex ratio was established, thus confirming a central premise underlying the theory of sex-ratio evolution.
Assuntos
Alcoolismo/epidemiologia , Transtornos Mentais/epidemiologia , População Rural , Mudança Social , Meio Social , Fatores Socioeconômicos , Adaptação Psicológica , Adolescente , Adulto , Alcoolismo/psicologia , Estudos Transversais , Feminino , Seguimentos , Humanos , Masculino , Transtornos Mentais/psicologia , Pessoa de Meia-Idade , Escalas de Graduação Psiquiátrica , Fatores de Risco , Escócia/epidemiologiaRESUMO
Thirteen patients with intracerebral malignant melanoma underwent high-field-strength (1.5-T) magnetic resonance (MR) imaging. The images were correlated with computed tomography (CT) scans (n = 7) and surgical specimens (n = 7). Most commonly, these lesions were hyperintense to normal white matter on T1-weighted images and hypointense to normal white matter on T2-weighted images. Hemorrhage in the lesion may have a greater influence on this unique appearance than does melanin. The increased tissue sensitivity of MR imaging allowed for 22% greater lesion detection than did CT.
Assuntos
Neoplasias Encefálicas/diagnóstico , Espectroscopia de Ressonância Magnética , Melanoma/diagnóstico , Adulto , Idoso , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/secundário , Hemorragia Cerebral/diagnóstico , Hemorragia Cerebral/etiologia , Hemorragia Cerebral/patologia , Humanos , Espectroscopia de Ressonância Magnética/métodos , Melanoma/patologia , Melanoma/secundário , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Tempo , Tomografia Computadorizada por Raios XRESUMO
Two patients with suprasellar cysts and hyperprolactinemia are described. These lesions were diagnosed by CT metrizamide cisternography. Suprasellar cysts are a rare cause of pathologic hyperprolactinemia, which most commonly results from pituitary adenomas. Tissue diagnosis revealed suprasellar arachnoid cysts in the first patient and Rathke's cleft cyst in the second. The differential diagnosis of suprasellar cysts is presented, and distinguishing radiographic characteristics are discussed.
Assuntos
Craniofaringioma/complicações , Hiperprolactinemia/etiologia , Neoplasias Hipofisárias/complicações , Adenoma/diagnóstico por imagem , Adulto , Craniofaringioma/diagnóstico por imagem , Diagnóstico Diferencial , Feminino , Humanos , Metrizamida , Neoplasias Hipofisárias/diagnóstico por imagem , Tomografia Computadorizada por Raios XRESUMO
Negative ulnar variance is a condition in which the ulna is relatively shorter than the radius at the carpus. It was found in 21% of 203 normal wrists. We have observed an increased incidence (49%) of this anomaly in patients with carpal ligamentous instabilities (dorsiflexion instability, palmar flexion instability, scapholunate dissociation with rotary luxation of the scaphoid, and lunate and perilunate dislocations). While the reasons for this association have yet to be adequately delineated, the presence of a negative ulnar variant may serve as an impartial clue to the presence of ligamentous instability. Many carpal instabilities present with subtle radiographic findings requiring careful evaluation of radiographs. Patients with negative ulnar variance and histories suggestive of ligamentous instability should undergo careful radiologic evaluation to assure early diagnosis of carpal disruption.
Assuntos
Fraturas Ósseas/diagnóstico por imagem , Luxações Articulares/diagnóstico por imagem , Ligamentos/lesões , Ulna/diagnóstico por imagem , Traumatismos do Punho/diagnóstico por imagem , Adulto , Ossos do Carpo/diagnóstico por imagem , Humanos , RadiografiaRESUMO
Fourteen male rape victims treated in a county hospital emergency room over a 30-month period are compared with 100 randomly selected female victims treated over the same period. The male victims as a group sustained more physical trauma, were more likely to have been a victim of multiple assaults from multiple assailants, and were more likely to have been held captive longer. They were more reluctant to reveal initially the genital component of their assault and were more likely to use denial and control their emotions in reaction to the assault. Proper diagnosis and treatment of male rape victims requires a high index of suspicion and sensititivty to the likelihood of major, hidden trauma.
Assuntos
Homossexualidade , Estupro , Adolescente , Adulto , Criança , Negação em Psicologia , Humanos , Masculino , Ajustamento Social , ViolênciaRESUMO
Between 20 July and 15 Octoboer 1975, five cases of human infection with Babesia microti were diagnosed on Nantucket Island, Massachusetts. The illness was characterized by fever, drenching sweats, shaking chills, myalgia, arthralgia, extreme fatigue, and a mild-to-moderate hemolytic anemia. None of the patients had a history of splenetomy. Although all patients responded symptomatically to treatment with oral chloroquine phosphate, parasitemia and fatigue frequently persisted for several weeks to months.