Processes of disease concerning jaundice pigmentation calcification and amyloid

At first, my outlook on these processes were of a superficial nature until attending these lectures. My perception of calcification, pigmentation, amyloid and jaundice completely changed: these were terms that I had a basic understanding of but the in-depth presentation of this work allowed me to perceive it differently.

Amyloid from my basic understanding is abnormal protein material being deposited extracellularly in either organs or tissues, often in blood vessel walls; this is known as amyloidosis. Organs affected by amyloid may appear to be firm, waxy and enlarged. (mayoclinic, 2011).There are a few staining methods which are used to identify amyloid:

  • Congo red
  • Iodine
  • Methyl violet
  •  Thioflavin T
  • Immunohistochemical stains

Amyloid can be classified in many ways:

  • According to the cause or associated disease.
  • Whether generalized throughout the body or localized to one site.
  • According to chemical composition of the amyloid material deposited.
  • According to the sites of deposition of amyloid.

An example of amyloid is localized amyloid this is due to aging and certain conditions of the endocrine glands which results in deposits in various organs e.g. the lung and larynx. In some cases there is localized nodular deposition of amyloid, the material is of the amyloid light chain type, this suggests a possible local immune response. Different biopsies are done due to amyloid being able to affect different organs. I understand this to be extremely important as in many cases amyloid may be dangerous and incorrect diagnosis and treatment may lead to further progression of disease and death.

Calcification- Calcification is a process in which calcium builds up in body tissue, causing the tissue to harden. (thefreedictionary, 2007). This can be a normal or abnormal process. Heterotopic calcification I understand to be basically the abnormal deposition of calcium, which would be anywhere in the body besides the teeth and bones. The von kossa stain is used mainly for the identification of calcification. There are two main types of calcification:

Dystrophic- this is the local deposition of calcium salts in dead or degenerate tissue.

Metastatic calcification- this is when there is a disturbance of calcium metabolism which is associated with hypercalcaemia.

Calcium favors alkaline environments and thus is often deposited in the kidneys where it affects excretion.   There are many causes of hypercalcaemia:

  • Primary hyperparathyroidism
  • Excessive absorption of calcium e.g. vitamin D hypersensitivity

I realized that the link between amyloidosis and calcification is that in an attempt to protect itself the body would calcify the amyloid blocking it off and this calcification may lead to ischemia or even renal failure. Therefore I feel that this is of major importance in human disease.

Pigmentation may be due to either exogenous or endogenous factors. Exogenous refers to dust heavy metals and miscellaneous factors whereas endogenous is due to melanin lipofuscin and the breakdown of hemoglobin.

Exogenous process

  • Carbon inhaled
  • Phagocytosed by alveolar macrophages
  • Transported via lymphatic’s
  • To tracheobrachial lymph nodes
  • Dust blackens nodes and pulmonary parenchyma
  • Causing anthracosis- blackening
  • Results in emphysema/ fibroblastic reaction
  • Results in lung disease e.g. pneumoconiosis

Tattoos are done by the insertion of pigments into the dermal layer. Melanin is a pigment made by our bodies to protect us from ultra violet rays and also plays a role in skin color. In the absence of the production of melanin albinism may occur or vitiligo.

I believe this chapter links to jaundice as bilirubin is also a type of pigment causing the coloration of the feces and sclera (diseased person), this emphasizes its importance in health and disease.

Jaundice – excess bilirubin in tissues. (thefreedictionary, 2007).

Mechanism

  • RBC breakdown + red bone marrow+ innefective erythropoiesis etc
  • Forms unconjugated bilirubin
  • Transported via albumin to the liver
  • Taken up by hepatocytes
  • Binds to ligandin
  • Transport to Endoplasmic reticulum
  • Becomes conjugated by action of glucoronyl transferase
  • Transported across cell membrane (active process) to bile canaliculi
  • Then to the gall bladder
  • Which is then secreted in the intestines
  • Most is deconjugated by Beta glucoronidases to urobillogen
  • Some excreted in feces some reabsorbed entering circulation
  • Some excreted through kidneys and the rest back to the liver

The liquid deposited into the intestines is known as bile it has four main functions

  • Cholesterol elimination
  • Hepatic catabolite elimination
  • Emulsify lipids and fat
  • Decrease biliary tract and intestinal bacteria

Process of jaundice:

  • Increase in unconjugated bilirubin due to bilirubin over production, decrease in hepatic uptake of bilirubin or decrease in bilirubin conjugation.
  • Increase in conjugated bilirubin due to decrease cellular secretion, impaired canalicular bile flow or extra hepatic biliary obstruction.

Through reading these chapters I realized there is a common ground between these chapters and that they are of importance as they have the ability to cause disease and even death.

References

Mayoclinic, 2011. Amyloidosis. [Online] Available at: < http://www.mayoclinic.com/health/amyloidosis/DS00431 > [Accessed 4 March 2013]

Thefreedictionary, 2007.Calcification. [Online] Availbable at: < http://medical-dictionary.thefreedictionary.com/calcification > [Accessed 3 March 2013]

Thefreedictionary, 2007.Jaundice. [Online] Available at: < http://medical-dictionary.thefreedictionary.com/jaundice > [Accessed 3 March 2013]

ImagevitiligoImagejaundiceImageImage

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