The start of Immunology… (Day 57)

Immunology Tube Agglutination test Seriology

Today I started the immunology section of the Microbiology module, rumours at the minute are that people on the 6 year course get to do this over 13 weeks whilst for us we have just 5 weeks which does demonstrate just how intense the course is. Personally I have already done a Immunology module in the past so I am pretty lucky with this just as a refresher (yay!) though I am trying to avoid getting exemption as its more challenging to do the exams as well!

So starting with the basics, immunology is the study of the immune system which is responsible for the bodys defences against disease and injury. It is split into two parts, the adaptive and the innate immune responses.

The innate immune system is most likely to be active at the sites that are the primary point of contact with the outside world. So for example the skin, respiratory tract, gastrointestinal tract, urogenital tract and the ocular mucosa. Each of these areas have special adaptions to prevent disease from entering the body, whether it is sebum and sweat (both contain anitmicrobials) which is secreted by the skin, or the cilia that lines the respiratory mucosa to transport foriegn particles upwards out of the lungs. In addition within the blood there are leucocytes such as neutrophils, macrophages, and natural killer cells that are continuously present which are ready to spring to defend against invaders. This response is relatively weak when compared to the adaptive immune response however can hold pathogens at bay for short periods of time. The innate immune system is also responsible for inflammation (which is indicated by the 5 cardinal signs: pain, swelling, heat, redness and loss of function) which help deal with the molecules released from dead or damaged cells.

The adaptive immune system however is stronger in being able to deal with pathogens, however it takes longer for the adaptive immune response to occur (usually 4 – 7 days). The adaptive immuned response is based around T lymphocytes (and the cytokine and chemokine messenger molecules) and the B lymphocytes which produce antibody. It also has a regulatory function to allow “switching off” after the pathogen has been destroyed so as not to damage the normal body tissues. Now this leads onto probably the most essential piece of knowledge, the adaptive immune system has memory, so when it encounters the same pathogen again the response is more effective and faster. This is why vaccination works, vaccination adds the pathogen into the memory bank of the immune system allowing it to deal with it before it gets a hold if it is ever encountered later on. This phenomenon is known as the secondary immune response.

When thinking about the different immune responses it can be likened to a an army patrol (the innate immune system) coming across the enemy when on patrol and sending for help from the main army base (the adaptive immune system) which then turns up to win the war.

Anyways back to the actual practical session, today we looked different methods of testing for disease through blood serum antigen (immune response causing particles) and antibodies (markers that attach to antigens) levels. One of the most valuable tests within seriology is the determination of how bad the disease actually is, and whether it is acute or chronic. This is done by a simple agglutination test either in a test tube, on a microscope slide or with a commercial kit.

Immunology Tube Agglutination test SeriologyUsing this test a serum sample is mixed with a solution that contains the associated antibodies or antigens for what is being tested. If it is a positive test the antibodies will bind to the antigens and form clumps (agglutinate).

Anyways enough for today! I’ve got to get back to Latin, until tommorow! Thank you to everyone that has supported me, even a £1 really does help and you can do it securely on the right of this page!

The pretty colors of Microbiology… (Day 15)

The colorful microbiology practical

Today was pretty interesting, this mornings Microbiology lecture was on cell structure (I can see a theme for this week after Histology and Physiology yesterday also being on a similar topic. Going have to brush on my cell biology as if its getting this much attention then its gotta be pretty important! One of the things I consider most imporant within this is the difference between Gram positive and Gram negative bacteria. Most bacteria cells have a wall around them which controls the transfer of stuff in and out of the cell. This affects what types of antibiotics can be used in treatment, as to the diagnostic techniques used in the identification of it.

Anyways after this lecture it is time for a quick break and then onto the practical session, I was kinda excited to see how well I had done innoculating my plates in last weeks practical. Today we walked into a set up of loads of different coloured plates like this…

The colorful microbiology practicalSometimes I really do have to just stop and admire just how beautiful nature really is. Considering that all the bacteria on these plates can do harm to us its amazing how they manage to look so pretty.

Anyways enough of that, todays practical introduction was on the different mediums available to culture (grow) bacteria, how they are prepared and why they change the colours they do. Through my undergrad it had been a case of it just was, now I am learning the why and I am so much happier actually understanding this.

Culture media is important as when trying to determine a bacteria you basically test different properties to determine which it is. Within the selection we had today we had selective media (which restricts the type of bacteria that will grow on it), differentiative media (which tests a common property between negative and positive), and media specifically for the detection of pigment production by bacteria.

Basically agar is just a plain power that is mixed with water and then sets almost like Jelly. For selective media chemicals such as crystal violet and bile salts which restrict the growth of Gram positive bacteria (hence making it selective). For differentiative bacteria indicators are added to detect the presence of things such as pH or lactose which causes a change in color. And for special media chemicals are added to react with specific properties such as thiosulfate which is metabalised by Salmonella and forms colonies of bacteria with black centers.

Today we had prepared plates to examine the difference appearence of different bacteria on different culture media which was pretty cool. When you start to look at the differences you really do start to appreciate that a cell is alive, it eats, it puts out waste and its amazing how this happens with something so small.

Different types of microbiology agarWe then looked at the different types of growths, shapes of colonies, and then using liquid medium as well for growth in a test tube. The growth and culture of anaerobic (without oxygen) bacteria using oxidation-reduction and an anoxic jar.

The end of my first week in Vet School (Day 11)

Staining the mouse testes in acetic-orcein

Today was Friday, and was probably one of the lectures I’d been dreading most as the older years have said that this professor loves to fail people… So I headed to genetics and prayed that he wouldn’t pick me to fail, todays lecture was an introduction followed by looking at Mitosis (creating a replica of the cell (diploid as two sets of chromosomes)) and Meiosis (creating germ cell (haploid as one set of chromosomes)) in depth with and the interactions of this on  the chromosomes. I guess this kinda was revision, however I am going need to spend a couple hours here with my own book to get the processes spot on as I have not done it in a while.

This was then followed by the practical for Milk Hygiene, during which this week was mainly a recap of the previous lecture we had. We did however discover the power of questions as in shops here they seperate what we have always assumed to be milk products into two sections. Basically with milk products sometimes to reduce the cost producers replace milk cream with vegetable oil which then removes the product from the classifcation of milk products. So basically in the stores here there are milk products and then products that include milk. The rest of the lecture was on hygiene and process of hygiene and laboratory testing during milk production.

Note: Whilst I do have pictures of the dissection, I have made the decision not to include them within my diary as I want it to appeal to as wider range of readers as possible.

Our timetable got changed again leaving us with a 2 hour gap so we then all headed back to dorms, I did an hours studying and took a 30 minute nap. Also my bottle of water had leaked in my bag so put stuff out to dry. I then headed back to my Genetics practical with just my labcoat, notebook and genetics book. On sitting down the lab tech walked out and put a dead mouse in front of us, and was like collect the testes. I’ve never done anything with mice before so had no clue as to the anatomy of the urinary tract. Pulling a glove onto my left hand as I had a open wound I set about exploring my mouses abdomen with scalpel and scissors. I was very conscious about not damaging any internal structures but with limited dissection experience and no clue as to the anatomy was a little nervous. I opened to skin layer exposing the peritoneum (basically a sack that surrounds the abdomen organs). Now I had already admitted to knowing nothing about mouse anatomy so this was kinda cool, and I then opened the peritoneum exposing the organs. Now in relation to the size of the penis, the testes were large about the size of small marbles which suprised me a little. I harvested one and passed the mouse onto the next group for the other. The teste was then cut up into very small pieces and stained in acetic-orcein (which is a red stain) before being examined under the microscope.

Staining the mouse testes in acetic-orceinThe cells were then examined under the microscope to look for germ cells in different stages of maturity before they actually formed sperm cells. I am awful at recognising things under the microscope from paper (especially when it is black and white), however others in the class managed and I looked at the cells under their microscopes before then finding it with my own. We then also examined a onion root to look at the different stages of mitosis.

On the way out as the campus was so quite I decided to get a picture with Ardo, the bronze horse that has a long and interesting history within Kosice (I am not entirely sure of the whole story so will cover this another time when i know!).

Chris with Ardo the bronze horseMy first week of lectures in vet school is now over, its been a week of early starts, late finishes and yet I love it and have never been happier! This weekend is now for revision, and more importantly I need to really work on my diary and letter writting to try and raise the £4000 that I need to continue studying here in February!