The rich diversity of avian natural history provides exciting possibilities for comparative research aimed at understanding three-dimensional navigation. We propose some hypotheses relating differences in natural history to potential behavioral and neurological adaptations possessed by contrasting bird species. This comparative approach may offer unique insights into some of the important quest...

The newborn infant with atypical genitalia presents a challenging clinical scenario and requires expert input. There have been appreciable advances in our knowledge of the underlying causes that may lead to a mere difference or a more serious disorder of sex development (DSD), the natural history of conditions, as well as the short and long-term complications of these conditions themselves, tog...

Scarcely any invention has altered biological science so radically in such a short period as the polyme-rase chain reaction, or PCR. With this technique, minute amounts of DNA can be replicated very rapidly and thereby amplified to such an extent that the DNA becomes easy to detect, study and use for any given purpose. The potential of this technique in medicine has long been known, and ever mo...

BACKGROUND Lead time, the estimated time by which screening advances the date of diagnosis, is used to calculate the risk of overdiagnosis. We sought to describe empirically the distribution of lead times between an elevated prostate-specific antigen (PSA) and subsequent prostate cancer diagnosis. METHODS We linked the Swedish cancer registry to two independent cohorts: 60-year-olds sampled i...

an animal disease which he called 'cowpox'. This paper discusses recent evidence concerning the natural history of cowpox which suggests that earlier views on it may have been incorrect. In the 19th century valuable information was obtained about cowpox. However these studies in part pre-dated acceptance of the germ theory of disease, and all pre-dated the development of laboratory techniques. ...

Neurofibromatosis is a common disorder that affects approximately 1 in 3000 persons [1]. Segmental neurofibromatosis is a rare form of the disease in which the cutaneous and neural changes are confined to one region of the body. Because the natural history and genetics of the segmental type may be different from those of the more common forms, it is important to become familiar with this unusua...

Anterior knee pain in adolescents is generally recognised as a common but benign self-limiting condition. Although many operative procedures for its treatment have been proposed, there is little statistical evidence that they are more effective than expectant management. A group of 54 adolescent girls has been followed for two to eight years from presentation with anterior knee pain. Although s...

OBJECTIVE To evaluate the knowledge on developmental dysplasia of the hip (DDH) by professionals involved in its diagnosis. METHODS This is a cross-sectional study using questionnaires to assess the knowledge about DDH. Orthopedic surgeons and pediatricians, residents and medical students from a tertiary teaching hospital were included in the study. RESULTS We evaluated 142 medical students...

The monotypic linyphiid genus Lomaita Bryant 1948 is redescribed. We present an updated description of the male of L. darlingtoni, the first description of the female and data on its natural history and distribution in the Dominican Republic. We provide a hypothesis on the phylogenetic placement of Lomaita based on cladistic analyses of morphological characters.

OBJECTIVE This article is the third in a 4-part series on women's health issues and nuclear medicine. After reading this article the technologist should be able to: (a) state potential risk factors for osteoporosis; (b) describe osteoporosis and its natural history; and (c) identify methods for detecting normal and abnormal bone mineral density results.