#96 Cystic Fibrosis (English)

What is it?

Cystic fibrosis is a genetic disorder that affects mainly the lungs but it can also affect the pancreas, liver, kidneys, and intestine. Cystic fibrosis affects the cells that produce mucus, sweat and digestive juices. It causes the secretion to become sticky and thick. As normal mucus, sweat and digestive juices are meant to act as a lubricant, in people with cystic fibrosis, because it's so thick, it blocks passageways and causing difficulty breathing.

Life expectancy of someone with this disease is 35 years, but individuals with adequate pancreatic function, life expectancy is 50 years. 

Causes

It's caused by a mutation in the gene called cystic fibrosis transmembrane conductance regulator, also known as CFTR. There are several possible mutations to the gene, it can create a protein that does not fold properly and is degraded to the cell and it can also cause proteins to be too short due to a premature end to production. Some other mutations to the gene are ones that do not allow chloride, iodide and thiocyanate to pass.

However, for cystic fibrosis to occur, the child has to inherit a copy of the gene from both parents. If they only inherit one, they won't develop cystic fibrosis but will be carries and could pass it onto their children.

Symptoms

-    salty-tasting skin

-    Poor growth & poor weight gain despite normal food intake

-    Clubbing of fingers & toes

-    Sticky & thick mucus

-    Frequent chest infections

-    Constant coughing

-    Males can be infertile

Complications

-    Bronchiectasis, a condition that damages airways blocking air from entering and existing the lungs

-    Chronic infections such as bronchitis and pneumonia as the mucus provides and ideal environment for bacteria and fungi

-    Nasal polyps, which are soft, fleshy growths that can develop inside the nose as its lining is inflamed. Can obstruct breathing during sleep

-    Respiratory failure, over a long period of time the damage of cystic fibrosis can be so bad and damage lung tissue so much that it no longer works.

-    Nutritional deficiencies, prevent digestive enzymes from traveling to your large intestine

Diagnosis

-    Sweat test, to see if it's saltier than normal

-    Genetic testing, DNA sample from blood to see if there are defects of the CFTR gene 

Treatment

There is no known cure for cystic fibrosis, but some treatments can ease symptoms and reduce complications.

-    Medication; prevents and treats lung infections, mucus thinning drugs can be used to expand the airways, medicine that relaxes the muscles around your bronchioles.

-    Chest physical therapy; helps loosen mucus and therefore makes it easier to cough up.

-    Surgery; nasal polyp removal, endoscopy & lavage which is the suction of the mucus and even a lung transplant might be necessary when the mucus causes severe breathing problems.

-    Feeding tubes; since it interferes with the release of digestive enzymes, feeding tubes may be used to provide the patient with necessary nutrients.

KHL

#95 The Zika Virus (English)

The Zika virus is a member of a virus family that is transmitted by mosquitoes and was first discovered within the Zika Forest of Uganda. It is a member of the Flavidviridae family and often causes no or mild symptoms. Zika is quite an old virus and only recently experts have been worried about as it only had affected a concentrated area however once it began to spread, people became more aware about the serious consequences it could have

1.Areas with Zika

Prior to 2015, Zika virus outbreaks occures in Africa and Asia aswell as the Pacific Island howevere in 2015 it began to spread to Brazil and has been continuing to spread and i twill be difficult to determine how and where the virus will spread over time. Zika has begun to spread to American territories such as Puerto Rico, the US Virgin Islands and American Samoa.

2. What happens if you get Zika?

The serious problem with this virus is that in most cases, it causes no symptoms at all and therefore patients that have Zika don’t seek any medical attention. However if you do receive symptoms they tend to be low evers, sore body, heady ache as well as red eyes anda body rash.

A patient that is aware of Zika can be treated simply by taking medication such as Tylenol to relieve the fever or pain and to take other anti inflammatory drugs to make sure no swelling starts to occur. The main treatment is to drink fluids to prevent dehydration and to get plenty of rest.

Zika is not spread from human to human but by mosquitoes however there have been some special cases in which one has gotten the Zika virus without getting stung by the mosquito himself. If a Zika transmitting mosquito bites a human and then a normal mosquito that gives mosquito bites, bites the same person and then goes a long to bite another the nit is possible for this second person to be affected by the Zika Virus. It is possible for Zika to be sexually transmitted however only spreads from men to women and not vice versa. Also, Zika can be spread during labour and blood transfusion. Furthermore, Zika seems to live in saliva and urine however it is not cleat if it can be spread through these fluids just yet

Zika and Pregnancy

Zika virus can be passed from a mother to her baby during pregnancy. Zika affected mother can lead their babies to develop microcephaly which is a birth defect that is associated with a small head and incomplete brain development in newborns.

HIB

#94 Molecular biology: DNA and RNA (English)

[IB SYLLABUS]
Label and annotate the structure of a single nucleotide

copyright KSJ

DNA is a double helix, it has two strands that twist around each other. Each of these strands is known as a nucleotide(see left). Nucleotides are made of phosphate, deoxyribose sugar, and a base.

Phosphate

•   Acidic

•   Negatively charged

Deoxyribose sugar

•   5 carbon atoms= pentose sugar

•   If the sugar is deoxyribose, the polymer is DNA

•   If the sugar is ribose, the polymer is RNA

Base

•   Contains nitrogen

•   Has one or two rings in its structure

State the type of bond that joins A to B and A to C

Covalent bonds

Write down which bases pair with each other(complementary base pairs)

There are four possible bases: cytosine, guanine, adenine, and thymine. Cytosine always pairs with guanine and adenine always pairs with thymine. To easily remember this, just remember the acronym 'AT' which stands for adenine and thymine. If we know this, then we can assume that guanine and cytosine are the other pair.

Distinguish between DNA and RNA

Draw a section of DNA, showing two anti-parallel strands if four nucleotides each. Label the bonds which hold the bases together as well as the correct complementary base pairs

Copyright PoS

Two benefits of modeling rather than an experimental approach

•   Allows people to visualize the molecule

•   Lets people see how well it fits with the available evidence

Outline the reasons the first model was rejected

•   Ratio of adenine to thymine was not 1:1

•   Required too much magnesium

Two key discoveries concerning of DNA that were found quickly after the model was published

•   DNA must be a double helix

•   Strands must be anti-parallel to allow base pairings to happen

Give an example of the work of other scientists that supported Watson and Crick's discovery

•   Rosalind Franklin and Maurice Wilkins, who used X-ray diffraction

PoS

#93 Рак поджелудочной железы (Pancreatic cancer) (Русский)

Рак поджелудочной железы является одним из самых агрессивных типов онкологии. Наиболее распространенной формой рака поджелудочной железы является аденокарцинома.

Что провоцирует рак поджелудочной железы?
Существует ряд факторов, которые могут привести к возникновению злокачественной опухоли:

• Заболевания поджелудочной железы – хронический панкреатит, кисты и доброкачественные новообразования
• Сахарный диабет
• Курение (до 30% случаев)
• Алкоголизм (до 20% случаев)
• Профессиональный риск – воздействие асбеста
• Перенесенные операции на желудке
• Неблагоприятные условия окружающей среды

Признаки рака поджелудочной железы:

• Боли в животе
• Желтуха, кожный зуд, потемнение мочи и осветление кала
• Снижение массы тела
• Потеря аппетита (анорексия)
• Тошнота и рвота
• Развитие вторичного сахарного диабета
• Увеличение селезенки
• Острый холецистит и острый панкреатит

Степени рака:

• I стадия – злокачественное образование имеет небольшие размеры. Оно не выходит за границы поджелудочной железы.
• II стадия – имеет две степени.
• 2А – раковая опухоль распространилась к желчевыводящему протоку или к двенадцатиперстной кишке. К лимфоузлам распространение не произошло.
• 2В – новообразование распространилось к лимфатическим узлам. Его размеры могут быть различными.
• III стадия – разрастание опухоли к желудку, селезенке и толстому кишечнику. Она может распространиться к крупным нервам и сосудам.
• IV стадия – опухоль распространяется по лимфоузлам, появляются метастазы в другие органы.

Диагностика:
Прежде чем начинать лечение рака поджелудочной железы, необходимо провести диагностику заболевания. Главным методом определения онкологии является КТ. Однако для окончательного диагноза необходимо провести пунктирование: биопсия с морфологическим исследованием под контролем КТ и УЗИ. Опухолевый маркер 19.9 СА не отличается большой информативностью. Однако желательно определить его на этапе диагностирования, потому что в ряде случаев эти данные могут понадобиться уже на этапе лечения.

Лечение:
Лечение рака поджелудочной железы чрезвычайно сложная задача. Единственным способом радикального лечения является оперативное вмешательство.
При раке тела и хвоста поджелудочной железы выполняется ее резекция с удалением селезенки.
При раке головки поджелудочной железы выполняют гастропанкреатодуоденальную резекцию. Операция заключается в пересечении поджелудочной железы в области перешей-ка, двенадцатиперстной кишки — в области ее перехода в тощую, желудка — в антральном от-деле и общего желчного протока — в дистальной части и удалении резецированной зоны одним блоком с последующим восстановлением непрерывности пищеварительной трубки. Большому числу больных из-за запущенности процесса или тяжести общего состояния выполнение радикального вмешательства невозможно. Лечебная помощь таким больным на-правлена на ликвидацию желтухи. Эффективность лучевой и лекарственной терапии при раке поджелудочной железы крайне низка.

KAA

#92 Mitosis (English)

Mitosis is the division of the nucleus into two genetically identical daughter nuclei. In other words, most of our cells (except sex cells) have the ability to clone themselves, a process that is very much central to our lives.  In summary mitosis is required for 4 functions:

1.      Growth: multicellular organisms increase their size by increasing their number of cells through mitosis.

2.      Asexual Reproduction: several eukaryotic organisms reproduce asexually through mitosis.

3.      Embryonic Development: in order to develop, a zygote (a fertilised egg) will undergo mitosis and differentiation in order to develop into an embryo.

4.      Tissue repair: damaged mitosis can recover damaged tissue by replacing damaged/dead cells.

 

The cell cycle is divided into phases. Interphase is where the cells spend the majority of their time.  It consists of the parts of the cell cycle that don’t involve cell division. 

 

The cell’s preparation for mitosis, known as Interphase, is further divided into five stages:

·         G0 – resting stage of the cell. (not included in this diagram)

·         G1 (Gap 1) – the cell increases the volume of the cytoplasm, produces organelles and synthesises proteins.

·         S (Synthesis)  - the DNA is replicated.

·         G2 (Gap 2) – the cell essentially does the same as in G1. 

The mitotic phase is much more complex than those previously mentioned, and consists of 4 different stages.

1.      Prophase:

-        Centrosomes move to opposite poles of the cell and spindle fibres begin to form between them.

-        DNA supercoils (chromatins condense with the help of specific proteins called histones) and become what we call ‘sister chromatids.’

-        The nuclear membrane breaks down. 

2.      Metaphase:

-        Spindle fibres (made up of microtubules) from each of the two centrosomes attach to the centromere of each pair of sister chromatids.

-        Contraction of the spindle fibres cause the sister chromatids to line up along the centre of the cell.

3.      Anaphase:

-        Continued contractions of the microtubule spindle fibres cause the separation of the sister chromatids (thus are now referred to as chromosomes.

-        Chromosomes move to the opposite poles of the cell. 

4.      Telophase:

-        Chromosomes now arrive at the poles and uncoil (de-condense) to chromatin.

-        Microtubule spindle fibres disappear

-     New nuclear membranes reform around each set of chromosomes.

 

SAG 

#91 Circadian rhythm II (English)

The circadian clock/rhythm is a 24 hour cycle that fells our bodies when to sleep and regulates many other psychological processes. The environment, like sunlight or temperature, affect the clock. This internal clock is controlled by the Suprachiasmatic Nucleus (SCN). The SCN is located in the hypothalamus in the brain and responds to light and dark signals. When there is light, the SCN sends signals by delaying the release of hormones and raising body temperature. The SCN can be separated into two parts, the dorsal and the ventral. The dorsal part of the brain works 24 hours regardless of the amount of light received. The ventral distinguishes between night and day. One natural human circadian rhythm is close to 24 hours and 11 minutes. Some indicators for measuring the timing of a mammal's circadian rhythm include:

• Melatonin secretion- During the daytime, Melatonin levels are low or there is no melatonin in the system. Production begins when the light levels begin to lessen. Melatonin is a hormone that helps regulate waking and sleeping cycles. People who have insomnia use melatonin supplements.

• Core body temperature- the average human adult's temperature is at a minimum at around 5am. Normally the minimum temperature is two hours before wale time. People who are 'morning people' tend to have a minimum temperature at 4am while evening types of people had a minimum temperature at around 6am. Morning people have their lowest body temperature closest to the middle of their sleep period while evening people have it closer to waking time

Jet lag is an example of needing to reset our internal clocks. For example, If you travel from Switzerland to India, you lose 4 hours and 30 minutes. You will probably have trouble going to sleep at 10pm there because it will feel like it is 5:30pm to your body.

However, circadian clocks are not the only biological clocks that humans have. Different organs have different clocks, including the: liver, heart, lungs, intestine, and even the skin. These organs are normally only impacted by factors like meal times, and temperatures of the environment rather than light.

PoS

#90 Red Bull Health Risks (English)

Red Bull Health Risks

Does it give you “wings”?

Contrary to popular belief Red Bull does not actually give you wings. but does make you very “buzzed” and stimulated.

Red Bull is a popular brand of energy drinks that is sold by an Austrian company. Red Bull comes in many different varieties such as Red Bull “sugar free”, Red Bull “total zero” and many other fruity options.

Energy drinks are very useful to give you that extra shot of boost you need in the morning or before a sports activity. But before you start drink 5 in a row for “more energy” you need to be aware of the health risks posed with drinking red bull.

Red bull is often mixed with alcoholic beverages to prevent you from “crashing” so you can stay awake. Alcohol is a depressant whereas red bull is a stimulant. (Red bull contains a lot of caffeine then the caffeine then blocks the adenosine molecule so your brain thinks you are not tired.) But these two mixed together will (according to research) sometimes cause abnormalities in heart contractions. Which later causes heart problems.

Red Bull has a lot of sugar in it (hence why it provides us with a lot of energy), an increase in the intake could lead to problems such as tooth decay and dental problems. (Tooth decay has been previously explained #72).

Linking back to sugar there has been a link to more people being overweight with the more energy drinks consumed. This could lead to serious diseases such as diabetes and obesity which are potentially life threatening.

This point only applies if you’re pregnant but research illustrates that pregnant women who exceed their 200mg of caffeine intake daily are twice as likely to be at risk of miscarriage. (If this were to happen it would be around the 20 week mark of pregnancy.)

In conclusion Red Bull is like any other energy drink with high sugar content. Just be aware of the health risks and possible problems that will arise from constant drinking. Less drinking of energy drinks the healthier you will be.

 

SSP