During four consecutive winters, prospective surveillance was conducted in cohorts of 608 healthy elderly patients and 540 adults with chronic heart or lung disease, and viral studies were also performed in 1388 adults hospitalized for acute cardiopulmonary conditions. Respiratory syncytial virus (RSV) infections developed annually in 3 to 7 percent of healthy elderly patients and in 4 to 10 percent of high-risk adults. In the hospitalized cohort, RSV infection accounted for 11 percent of patients with pneumonia, 11 percent of those with chronic lung disease, and 7 percent of those with asthma.

RSV infection in elderly and high-risk adults is associated with a disease burden similar to that of nonpandemic influenza A. Vaccination against RSV could offer substantial benefits in these adults.

The role of multidetector-row computed tomography (CT) in the diagnosis of pulmonary embolism remains to be determined. In this study, the combined use of multidetector-row CT and D-dimer assays allowed pulmonary embolism to be excluded without the need for lower-extremity ultrasonography.

Mutations in the HFE gene are associated with hemochromatosis. In this large study of an ethnically and racially diverse population, homozygosity for C282Y mutations in the HFE gene was more common in non-Hispanic whites (0.44 percent) than in Native Americans (0.11 percent), Hispanics (0.027 percent), blacks (0.014 percent), Pacific Islanders (0.012 percent), or Asians (0.000039 percent). Most C282Y homozygotes had elevated serum ferritin levels and transferrin saturation.

Rates of HFE mutations vary widely across ethnic and racial groups. Patients with mutations have higher iron levels than patients without mutations.

Polycythemia vera, essential thrombocythemia, and myelofibrosis are idiopathic myeloproliferative diseases. These investigators identified a mutation in a gene that encodes JAK2, a key signaling protein in hematopoietic progenitor cells. The mutation causes constitutive activation of JAK2, which in turn gives cells proliferative and survival advantages over normal cells.

This work shines a revealing spotlight on three enigmatic diseases. It opens new avenues of research, which could lead to improved diagnosis and treatment.

Thrombosis of the cerebral veins and sinuses affects mainly young adults and children. This potentially disabling or fatal condition is usually not diagnosed until a week after the onset of symptoms. This review article describes the clinical presentations of the disorder such as those that occur after a head injury or lumbar puncture. Therapeutic options include anticoagulation, thrombolysis, and measures to control intracranial hypertension.

A 48-year-old man came to the neurology clinic because of progressive weakness of his arms and legs and pain in the left leg. Enlargement of the sciatic nerve and multiple spinal nerve roots was seen on imaging studies. The patient's 29-year-old nephew had been given a diagnosis of neurofibromatosis; no other family members were known to be affected. A diagnostic procedure was performed.

A member of the platelet-derived growth factor family (PDGF-CC) is necessary and sufficient to induce neovascularization in two models of ischemia.