Issues getting one on one time with radiologist

Hi All

I am having some difficulties getting time to sit with the radiologist to discuss our patient, if I can’t confer with him by next week we will just have to go ahead with what we have. I am sure we can put together a comprehensive well thought out project regardless! Just wanted to let everyone know what was going on.

Kat

Paper Outline Requirements

Hi All

For those of you that will be taking on the arduous task of weeding through all of the research we have compiled for the most pertinent bits of information, I must make you aware of the format our paper will require; the AMA style. I know we are all more accustomed to the MLA format, but since this project is going to be highly publicized within the open lab forum we have been informed that it was necessary to adhere to a format befitting our field/project. Here is a link that will familiarize you with the required format http://library.stkate.edu/pdf/citeAMA.pdf. This is the format which medical professionals use when writing papers.

Kat

Patient Pathology Acute Cholecystitis

Hi All

I have gotten some of the images for our project. Since I took part in the patients¬†CT guided percutaneous cholecystostomy¬†I know there were several hundred images (which would be overkill and the hospital would’nt give me). I selected one I felt best demonstrated the size of the gallbladder in relation to the liver, as well as the needle being inserted to drain the excessive bile. I have also managed to get some flouro images from our patient and a list of what procedures he has had due to the cholecystitis.

Preliminary Research

Gallbladder

(Science: anatomy) a digestive organ which stores bile (produced in the liver), used in the digestion and absorption of fats in the duodenum. A muscular sac attached to the liver that secretes bile and stores it until needed for digestion. http://www.biology-online.org/dictionary/Gallbladder

Secretion of Bile and the Role of Bile Acids In Digestion

Bile is a complex fluid containing water, electrolytes and a battery of organic molecules including bile acids, cholesterol, phospholipids and bilirubin that flows through the biliary tract into the small intestine. There are two fundamentally important functions of bile in all species:

  • Bile ¬†¬†¬†¬† contains bile acids, which are critical for digestion and absorption of ¬†¬†¬†¬† fats and fat-soluble vitamins in the small intestine.
  • Many ¬†¬†¬†¬† waste products are eliminated from the body by secretion into bile and ¬†¬†¬†¬† elimination in feces.

Adult humans produce 400 to 800 ml of bile daily, and other animals proportionately similar amounts. The secretion of bile can be considered to occur in two stages:

  • Initially, ¬†¬†¬†¬† hepatocytes secrete bile into canaliculi, from which it flows into bile ¬†¬†¬†¬† ducts. This hepatic bile contains large quantities of bile acids, ¬†¬†¬†¬† cholesterol and other organic molecules.
  • As ¬†¬†¬†¬† bile flows through the bile ducts it is modified by addition of a watery, ¬†¬†¬†¬† bicarbonate-rich secretion from ductal epithelial cells.

In species with a gall bladder (man and most domestic animals except horses and rats), further modification of bile occurs in that organ. The gall bladder stores and concentrates bile during the fasting state. Typically, bile is concentrated five-fold in the gall bladder by absorption of water and small electrolytes – virtually all of the organic molecules are retained.

Secretion into bile is a major route for eliminating cholesterol. Free cholesterol is virtually insoluble in aqueous solutions, but in bile, it is made soluble by bile acids and lipids like lethicin. Gallstones, most of which are composed predominantly of cholesterol, result from processes that allow cholesterol to precipitate from solution in bile.

Role of Bile Acids in Fat Digestion and Absorption

Bile acids are derivatives of cholesterol synthesized in the hepatocyte. Cholesterol, ingested as part of the diet or derived from hepatic synthesis is converted into the bile acids cholic and chenodeoxycholic acids, which are then conjugated to an amino acid (glycine or taurine) to yield the conjugated form that is actively secreted into cannaliculi.

Bile acids are amphipathic, that is, they contain both hydrophobic (lipid soluble) and polar (hydrophilic) regions. The cholesterol portion of a bile acid is hydrophobic and the amino acid conjugate is polar and hydrophilic.

Their amphipathic nature enables bile acids to carry out two important functions:

  • Emulsification ¬†¬†¬†¬† of lipid aggregates: Bile acids have detergent action on particles ¬†¬†¬†¬† of dietary fat which causes fat globules to break down or be emulsified ¬†¬†¬†¬† into minute, microscopic droplets. Emulsification is not digestion per se, ¬†¬†¬†¬† but is of importance because it greatly increases the surface area of fat, ¬†¬†¬†¬† making it available for digestion by lipases, which cannot access the ¬†¬†¬†¬† inside of lipid droplets.
  • Solubilization ¬†¬†¬†¬† and transport of lipids in an aqueous environment: Bile acids ¬†¬†¬†¬† are lipid carriers and are able to solubilize many lipids by forming micelles ¬†¬†¬†¬† – aggregates of lipids such as fatty acids, cholesterol and monoglycerides ¬†¬†¬†¬† – that remain suspended in water. Bile acids are also critical for ¬†¬†¬†¬† transport and absorption of the fat-soluble ¬†¬†¬†¬† vitamins.

Role of Bile Acids in Cholesterol Homeostasis

Hepatic synthesis of bile acids accounts for the majority of cholesterol breakdown in the body. In humans, roughly 500 mg of cholesterol are converted to bile acids and eliminated in bile every day. This route for elimination of excess cholesterol is probably important in all animals, but particularly in situations of massive cholesterol ingestion.

Interestingly, it has recently been demonstrated that bile acids participate in cholesterol metabolism by functioning as hormones that alter the transcription of the rate-limiting enzyme in cholesterol biosynthesis.

Enterohepatic Recirculation

Large amounts of bile acids are secreted into the intestine every day, but only relatively small quantities are lost from the body. This is because approximately 95% of the bile acids delivered to the duodenum are absorbed back into blood within the ileum.

Venous blood from the ileum goes straight into the portal vein, and hence through the sinusoids of the liver. Hepatocytes extract bile acids very efficiently from sinusoidal blood, and little escapes the healthy liver into systemic circulation. Bile acids are then transported across the hepatocytes to be resecreted into canaliculi. The net effect of this enterohepatic recirculation is that each bile salt molecule is reused about 20 times, often two or three times during a single digestive phase.

It should be noted that liver disease can dramatically alter this pattern of recirculation – for instance, sick hepatocytes have decreased ability to extract bile acids from portal blood and damage to the canalicular system can result in escape of bile acids into the systemic circulation. Assay of systemic levels of bile acids is used clinically as a sensitive indicator of hepatic disease.

Pattern and Control of Bile Secretion

The flow of bile is lowest during fasting, and a majority of that is diverted into the gallbladder for concentration. When chyme from an ingested meal enters the small intestine, acid and partially digested fats and proteins stimulate secretion of cholecystokinin and secretin. As discussed previously, these enteric hormones have important effects on pancreatic exocrine secretion. They are both also important for secretion and flow of bile:

  • Cholecystokinin: The name of this hormone ¬†¬†¬†¬† describes its effect on the biliary system – cholecysto = gallbladder and ¬†¬†¬†¬† kinin = movement. The most potent stimulus for release of cholecystokinin ¬†¬†¬†¬† is the presence of fat in the duodenum. Once released, it stimulates ¬†¬†¬†¬† contractions of the gallbladder and common bile duct, resulting in ¬†¬†¬†¬† delivery of bile into the gut.
  • Secretin: This hormone is secreted in ¬†¬†¬†¬† response to acid in the duodenum. Its effect on the biliary system is very ¬†¬†¬†¬† similar to what was seen in the pancreas – it simulates biliary duct cells ¬†¬†¬†¬† to secrete bicarbonate and water, which expands the volume of bile and ¬†¬†¬†¬† increases its flow out into the intestine.

The processes of gallbladder filling and emptying described here can be visualized using an imaging technique called scintography. This procedure is utilized as a diagnostic aid in certain types of hepatobiliary disease. http://biology.about.com/library/organs/bldigestliver3.htm

 

 

Categories Layout

Hi All,

I have made several categories for us to keep our information more easily organized. If you would like to post something go to the dashboard, click add a new post and on the bottom right hand of the screen you will see a blocker with the categories

1. General Communications/Disscussions

2. Group Responsibilites

3. Power Point Presentation and Viual Images

4. Project Essay

5. Research Articles/Links

just check the appropriate box for your post.

Thanks!

Kat

Group Responsibilities

Hi All,

Several of us got together after the class elections to decide where and what we are going¬†to contribute in our group project. For those of you who were not in attendance please let us know what you want to do. So far we have Runie and Shapiro presenting, Michael¬†typing the paper, and Erica on the PowerPoint presentation.¬†I will be gathering information and images as well as lending a hand elsewhere, as need be. So Junior, Charles, and Guiseppe please throw a post out there to let us know what you want to do! As it stands we should all look for an interesting case at our hospital, but may I suggest we have a back up plan if nothing pops up in the next week or so. We should come up with a contingent topic….any suggestions?

Kat