Reactive airway disease (RAD) is an informal label that physicians apply to patients with symptoms similar to those of asthma. An exact definition of the condition does not exist. Individuals who are typically labeled as having RAD generally have a history of wheezing, coughing, dyspnea, and production of sputum that may or may not be caused by asthma. Symptoms may also include, but are not limited to, coughing, shortness of breath, excess mucus in the bronchial tube, swollen mucous membrane in the bronchial tube, and/or hypersensitive bronchial tubes. Physicians most commonly label patients with RAD when they are hesitant about formally diagnosing a patient with asthma, which is most prevalent in the pediatric setting. While some physicians may use RAD and asthma synonymously, there is controversy over this usage. More generally, there is controversy over the use of RAD as a label in the healthcare setting, largely due to the ambiguous definition that the term has. Since RAD is not recognized as a real clinical diagnosis, its meaning is highly inconsistent and may cause confusion and misdiagnosis within the medical community. There are also concerns with overtreatment and undertreatment with RAD amongst physicians, since there is little formality with the label.
Streptozotocin or streptozocin (INN, USP) (STZ) is a naturally occurring alkylating antineoplastic agent that is particularly toxic to the insulin-producing beta cells of the pancreas in mammals. It is used in medicine for treating certain cancers of the islets of Langerhans and used in medical research to produce an animal model for hyperglycemia and Alzheimers in a large dose, as well as type 2 diabetes or type 1 diabetes with multiple low doses. Usage
Streptozotocin is approved by the U.S. Food and Drug Administration (FDA) for treating metastatic cancer of the pancreatic islet cells. Since it carries a substantial risk of toxicity and rarely cures the cancer, its use is generally limited to patients whose cancer cannot be removed by surgery. In these patients, streptozotocin can reduce the tumor size and reduce symptoms (especially hypoglycemia due to excessive insulin secretion by insulinomas). A typical dose is 500 mg/m2/day by intravenous injection, for 5 days, repeated every 4–6 weeks. Due to its high toxicity to beta cells, in scientific research, streptozotocin has also been long used for inducing insulitis and diabetes on experimental animals. Streptozotocin has also been used for modeling Alzheimers disease through memory loss in mice. Mechanism
Streptozotocin is a glucosamine-nitrosourea compound. As with other alkylating agents in the nitrosourea class, it is toxic to cells by causing damage to the DNA, though other mechanisms may also contribute. DNA damage induces activation of PARP which is likely more important for diabetes induction than the DNA damage itself.