Dr. Michael Boyle with CFTR image in background

Research A to Z

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A single-celled organism that can cause disease when it enters the body, usually either through the mouth and nose (by breathing, eating or drinking), or the skin. In many cases, an antibiotic can be prescribed to help the body either eradicate or reduce the infection caused by the organism. Bacteria are directly or indirectly involved in the lung disease and damage that ultimately are responsible for increased respiratory symptoms in the vast majority of CF patients.




A procedure used to directly visualize the airways within the lungs and to obtain mucus or tissue samples to be used for diagnosis and/or treatment. The patient is sedated, and a long, thin, flexible fiber optic tube (bronchoscope) is advanced through the vocal cords and into the trachea and bronchi (branches) of the lungs. The physician usually uses a camera and video screen to visualize the lung’s airways and manipulate the scope.

CFTR (Cystic fibrosis transmembrane conductance regulator)

CFTR is located on chromosome 7 and encodes a chloride channel that sits on the surface of specialized cells throughout the body. Mutations in the CFTR gene lead to CF.

Epithelial cell

A specialized type of cell that lines the airways, intestines and other organs. A lining of epithelial cells is called the epithelium.

FEV1 (Forced expiratory volume in one second)

A measure of lung function that shows the amount of air a patient can forcefully exhale from the lungs in one second. This measure is compared to a predicted normal value that is based on the patient’s age and height.

FVC (Forced vital capacity)

The maximum amount of air that can be exhaled from the lungs after a maximum inspiration. This measure is compared to a predicted normal value that is based on the patient’s age and height.

Food and Drug Administration (FDA)

The federal agency responsible for approving medications for use in the United States.


A region of DNA that contains the sequence for a protein that has specific functions within the body.


A local response to cell injury that is marked by increased blood flow, redness, heat, pain, swelling, and often loss of function. Inflammation serves as the body’s mechanism to attempt to eliminate infection or injury, or to start the healing of damaged tissues.

Informed Consent

The process of telling people about a research study and what will be required if he or she decides to participate. The risks and possible benefits of the study will also be explained. An informed consent form is signed by both the researcher and the participant to confirm that these discussions have taken place and that all questions have been addressed.

Institutional Review Board (IRB)

A committee that reviews research studies that involve people. Any clinical study must be approved by an IRB before it can begin. There are several IRB committees that approve human research studies at Johns Hopkins.

Ion Channel

A passage in the cell surface that allows salts to enter or exit the cell.


A change in the DNA sequence of a gene which leads to a change in function. Many mutations lead to disease. Mutations in the CFTR gene lead to cystic fibrosis.

Nasal Potential Difference (NPD)
A test of salt transport in the cells lining the nose. Transport of ions such as sodium and chloride creates an electrical potential difference across the epithelium (or lining) of the airway. This nasal potential difference (NPD) can be measured in patients by placing an electrode on the lining of the nose. The NPD can be used as a diagnostic test for CF.


An egg from a frog that is used in laboratory studies that investigate ion channels.

Phase I Trial

A study that investigates the safety of a new drug or treatment.

Phase II Trial

A study that investigates both the safety and effectiveness of a new drug or treatment.

Phase III Trial

A large study that determines if a new drug or treatment is effective and should be approved for use by patients.

Phase IV Trial

A study that is usually done after a drug has been approved for use. This type of study is used to determine the safety of a drug in a large group of people. Everyone in the study uses the drug and a placebo is not used.


A substance used in a clinical research trial that has no active ingredients. The effect of a study drug is usually compared to a placebo.

Principal Investigator (PI)

Person who is responsible for a research study.


The plan for a clinical trial that includes how medications will be given and what testing will be perfomed.

Pseudomonas aeruginosa

Pseudomonas aeruginosa (P. aeruginosa) is a bacteria that is important because it can chronically infect, or colonize, the lungs of people with CF. P. aeruginosa is resistant to many antibiotics and capable of surviving in conditions that few other organisms can tolerate. P. aeruginosa is often encountered in hospital and clinical settings where it is a major cause of hospital acquired, or nosocomial, infections, but it can also be found in many other places that are readily accessible to patients. P. aeruginosa thrives in places with a great deal of moisture. The bacteria rarely causes infection in healthy individuals, but in individuals with CF it can cause increased cough and sputum production, weight loss, decreased lung function, and fatigue or malaise. Nearly 80 percent of people with CF are chronically infected with P. aeruginosa bacteria. Antibiotic therapy is usually aimed at reducing the amount of chronic infection.

Pulmonary Function Testing (PFT)

Evaluation of lung function by measuring the amount of air a patient is able to inhale and exhale. The patient is asked to perform several sequences of maximal inspiration and expiration, and a computer measures the amount of air going into and out of the lungs. The computer can then estimate the capacity and function of the lungs as compared to healthy individuals of the same size.


The process of assigning people into groups for a study so that each person has an equal chance to be given the study treatment. Randomization assures that the people in each group will have similar characteristics.

Research Coordinator (RC) or Study Coordinator (SC)

Person who conducts a research study. Responsibilities may include obtaining informed consent, keeping accurate records and dispensing medications and making measurements.


A research study participant.