Beta-blockers (β-blocker)

31/07/2009

Beta-blockers are a class of drug that block the action of epinephrine at sites on heart muscle and blood vessel cells walls. This allows the heart muscle to relax reducing the workload on the heart by slowing the heart rate, which allows the heart to pump more efficiently. In blood vessels this decreases blood vessel constriction, enhancing blood flow within the vessels.

Chabner, Davi-Ellen. 2007. The Language of Medicine. 8th ed. Saunders Elsevier, Missouri


Echocardiography

30/07/2009

A diagnostic technique that uses ultrasound to study to structure and motions of the heart. It is much more detailed than x-ray imaging.

Chabner, Davi-Ellen. 2007. The Language of Medicine. 8th ed. Saunders Elsevier, Missouri


Ultrasonography

29/07/2009

The use of ultrasound to produce diagnostic images. Ultrasonography is a technique used to visualize subcutaneous body structures including tendons, muscles, joints, vessels and internal organs for possible pathology or lesions.

 

Chabner, Davi-Ellen. 2007. The Language of Medicine. 8th ed. Saunders Elsevier, Missouri


Myelography

28/07/2009

X-ray imaging of the spinal cord after the injection of a radio-contrast agent into the subarachnoid space that surrounds the spinal cord.

 

Myelogram showing spondylolisthesis (anterior displacement, sliding, of one vertebra over another)

Chabner, Davi-Ellen. 2007. The Language of Medicine. 8th ed. Saunders Elsevier, Missouri


Cancer: Grading and Staging

27/07/2009

Cancer Classifications are based on the following characteristics:

  • location within the body, presence of metastases (stage)
  • microscopic cellular appearance, level of cell differentaiton (its grade)

Grading

Histologic grade refers to the level of cellular differentiation, how much the tumor cells resemble normal cells of the same tissue type. Nuclear grade refers to the size and shape of the cell nucleus in tumor cells. It is the percentage of tumor cells that are dividing

  • Grade 1: tumors are well differentiated and cells closely resemble cells of their normal parent orgin
  • Grade 2 and 3: intermediate in appearance, moderately or poorly differentiated
  • Grade 4: are highly undifferentiated and anaplastic (cells have gone backwards in their development to an nonspecialized or embryonic state)

Staging

  • staging is based on the extent of metastasis
  • 3 guiding characteristics are often used

1) Tumor – T: refers to the size and physical extent of the tumor

2) Node – N: refers to number of lymph nodes that have been invaded by the tumor

3) Metastasis – M: refers to the presence or abscence of metastases of the tumor cells

this is abbreviated TNM

  • The International TNM Staging System is often used

Chabner, Davi-Ellen. 2007. The Language of Medicine. 8th ed. Saunders Elsevier, Missouri

US National Intitute of Health. National Cancer Institute. 2009. Tumor Grade. Retrieved July 27, 2009 from http://www.cancer.gov/cancertopics/factsheet/detection/tumor-grade


3 Tumor Types

24/07/2009

1) Carcinoma

  • majority of tumors are of this type
  • derived from epithelial tissues (cells that line organs, glands)
  • ~90% of all malignancies are carcinomas
  • adenomas – benign tumors of epithelial, glandular origin

2) Sarcomas

  • malignant tumors
  • less common than carcinomas
  • derived from connective tissues (bone, cartilage, muscle, blood, lymph)
  • mesenchymal sarcomas – sarcomas derived from embryonic connective tissues

3) Mixed-Tissue Tumors

  • derived from tissues capable of differentiating into both epithelial and connective tissues
  • least common tumor type
  • mixed-tissue tumors are composed of several different cells types

Chabner, Davi-Ellen. 2007. The Language of Medicine. 8th ed. Saunders Elsevier, Missouri


Thyrotoxicosis

23/07/2009

Condition caused by hyperactivity of the thyroid gland resulting in over-secretion of thyroid hormone.

Symptoms:

  • Sweating
  • weight loss
  • tachycardia (increased heart rate)
  • nervousness

Chabner, Davi-Ellen. 2007. The Language of Medicine. 8th ed. Saunders Elsevier, Missouri