Genetic

Genetics is the field of biology that seeks to understand biological inheritance that is passed from generation to generation. Genetics comes from the word γένος (gene) which in Greek means "offspring".

The study of genetics to understand what exactly happens in the cell cycle (replicate our cells) and reproduction (meiosis) of living things and how they might, for example, between human biological characteristics are transmitted genotype (genome content specific to an individual in the form of DNA), physical phenotype, appearance and even personality.

The main object of study of genetics genes are formed by segments of DNA (double strand) and RNA (single strand), after transcripicion messenger RNA, ribosomal RNA and transfer RNA, which is synthesized from DNA . DNA controls the structure and operation of each cell, with the ability to create exact copies of itself, after a process called replication, in which the DNA is replicated.

Although genetics plays a significant role in the appearance and behavior of organisms is the combination of genetics [replication, transcription, processing (maturation of RNA] with the experiences of the body that determines the outcome.

Genes correspond to regions of DNA or RNA, two molecules composed of a chain of four different types of nitrogenous bases (adenine, thymine, cytosine and guanine in DNA), in which after transcription (RNA synthesis) is changed to thymine by uracil-the sequence of these nucleotides is the genetic information organisms inherit. Occur naturally in DNA double-stranded form, ie in that two strings of a string of nucleotides complementary to each other.

The nucleotide sequence of a gene is translated by the cell to produce a chain of amino acids, proteins, creating the order of amino acids in a protein corresponds to the order of the nucleotides of the gene. This is called the genetic code. The amino acids of a protein is folded in determining how a three-dimensional shape and responsible of the functioning of the protein. Proteins perform most functions that cells need to live.

Subdivisions of genetics

The gene is divided into several branches, including:

Classical Mendelian worries about the study of chromosomes and genes and how they are inherited from generation to generation.

Quantitative analyzes the impact of multiple genes on the phenotype, especially when these effects are small.

Molecular studies on DNA, its composition and how doubles. Likewise, studies the function of genes from the molecular point of view.

Evolutionary and population: is concerned with the behavior of genes in a population and how this determines the evolution of organisms. In genetics will find many familiar features in common of the family as eye color, skin color and hair color.

the cancer

Cancer is a group of diseases in which the body produces abnormal cells derived from the tissues themselves, more or less similar to the originals from which they come, and they can behave in different ways, but generally tend to lead to death to the subject from which carrier without proper treatment. (cancerous or cancerous cells) whose malignancy is variable according to organ systems. These are generally characterized by escape reproductive control that required their original function, losing its original capabilities, and over time, acquiring others that are not theirs, invading progressively and by different routes nearby organs, or even remotely via the lymphatic or hematogenous (by blood) with growth and division beyond the normal limits. (invasion of surrounding tissue and, sometimes, metastasis)

Cancer is caused by abnormalities in the genetic material of cells. These abnormalities can be caused by different agents carcinógenoss, and radiation (ionizing, ultraviolet, etc.), chemicals (from industry, snuff the smoke and pollution in general, etc.) or infectious agents (virus human papillomavirus, Burkitt's lymphoma). Other cancer genetic abnormalities are acquired during normal replication of DNA, not corrected the errors that occur during the same, or they are inherited and therefore occur in all cells from the source (causing an increased likelihood of trigger disease).

Cancer is usually classified according to the tissue from which cancer cells originate. A definitive diagnosis requires histological examination, although the first signs of cancer can be given through symptoms or radiographs. Many cancers can be treated and some cured, depending on the type, location and stage or state where you are. Once detected, treated with the appropriate combination of surgery, chemotherapy and radiotherapy

All tumors, benign and malignant, have two basic components in its structure:

The proliferating tumor cells, ie cells forming the tumor proper, which constitute the parenchyma.

Supporting stroma, consisting of connective tissue and blood vessels. These non-tumor tissues whose formation has been induced by the tumor itself.

Oncological nomenclature is based on parenchymal component. Using two classification criteria: firstly its benign or malignant, and second tissue in which they form.

According to the behavior of tumors:

characteristics of cancer

Benign tumors: Your name ends with the suffix-oma, simply, and the origin of the tissue from which the benign tumors may be: fibroma (fibrous tissue), myxoma (loose connective tissue), lipoma (fatty tissue), chondroma (cartilage), osteoma (bone tissue), hemangioma (blood vessel), lymphangioma (lymphatic vessels), meningioma (meninges), glomus tumor (supporting nerve tissue), leiomyoma (smooth muscle), rhabdomyoma (striated muscle tissue ), papilloma (epithelial tissue forming buds), adenoma (glandular tissue), teratoma (totipotent cells), nevus (melanocytes)

Some benign tumors derived from epithelial tissue end with the suffix "adenoma" because the original epithelial tissue forms glands, although we must bear in mind that there are many exceptions to the rules of nomenclature tumor. For example: A benign tumor of melanocytes or nevus Nevus is called, and as malignant melanoma.

Malignant tumors or cancer:

Cancers that arise from tissue or mesoderm mensenquimatosos called sarcomas (Greek sarcos, "meaty"), eg fibrosarcoma, myxosarcoma, liposarcoma, chondrosarcoma, osteosarcoma, angiosarcoma, lifangiosarcoma, sinoviosarcoma, leiomyosarcoma, rhabdomyosarcoma.

Malignant neoplasms of epithelial origin, arising from any of the three germ layers of the embryo are called carcinomas, eg squamous cell carcinoma or squamous cell, basal cell carcinoma, adenocarcinoma, cystadenocarcinoma, choriocarcinoma, carcinoma of the penis.

The tumors arising from nerve tissue are gliomas (actually it's not a tumor derived from nerve cells, but one of the cell types responsible for their support, glial cells, tissue "connective" of the brain, so to speak .)

Hematologic cancers are lymphomas and leukemias, always malignant (derived from myeloid and lymphoid tissue, respectively).

Malignant tumors that do not meet the above rules and ending-oma, are: melanoma, hepatoma, seminoma. There are also the mesothelioma, which originates in the serous membranes (pleura, pericardium, peritoneum), and can be epithelial or mesenchymal component 

cancer detection

One of the key problems in cancer treatment is early detection of disease. Often the cancer is detected in its later stages, when the function has committed one or more vital organ systems and is spread through the body. The methods of early detection of cancer are of utmost importance and are an active area of ​​current research. After the initial detection of a cancerous growth, the accurate diagnosis and parking of the disease are essential for designing a treatment plan. This process depends on the clinical trial and medical observations. It is important for cancer patients and their families understand the results given to them so they can take an active role in planning the treatment protocol shell.

Detecting cancer early is an important step to prevent major health problems. Almost universally, cancers are more easily treated if caught early. For the reason that early cancers are small and often have no symptoms, researchers have attempted to develop screening processes that are simple and cheap but they are also sensitive enough to detect these cancers. Such tests should be inexpensive and easy because the invasive and expensive procedures performed in healthy people would be unethical and ineffective at the level of ordinary people. Blood tests is a common and straightforward to detect cancer in its early stages. If a chemical in the blood that signals the presence of a small tumor can be detected, the cancer can be treated earlier and could be cured.

When a test is performed to detect a disease, there are four possible outcomes.

If a review says that the patient has a disease that the patient does have in reality, this is called a true positive.

However, if a review says that a patient has a disease when he does not possess in reality, this is called a

false positive.

If a review says that the patient has no disease, and this is the real case, this is called a true negative.

Finally, if a review says that the patient is healthy while the real case is that he is sick, this is called a false negative.

A perfect test gives positive and negative solamnete true, and the worst possible test would be to guess the outcome. While medical tests are quite accurate, all tests used in medicine fall between these extremes. The UNCERTAINTY results in some problems. A test that is positive is usually confirmed with a second more accurate test. If the second test is still simple, noninvasive, then take a preliminary test

 results in many false positive is acceptable. If a second test is difficult to achieve or risky, the initial blood test could make many people go through needless medical procedures

If the first test is not perfect, this may incorrectly indicate that patients are healthy, when in fact they are not. If a disease is mild and not affect the health of the patient, then the blood test has very little effect when wrong. If the disease is serious, the blood test can prevent patients from obtaining necessary care. The true value of any blood test is a balance between sensitivity and specificity of the test, and the severity of the disease detected. It is important that patients talk about the specificity and sensitivity of tests with their healthcare providers.

cancer treatment

Surgery is the method used for small tumors located in a particular place. To be fully effective it requires removal of the tissue surrounding the tumor so as to ensure that all cancer cells have been removed.

If the cancer has spread to other areas, through the blood or lymph, there shall be other treatments, either surgery or added to the unique and different to her.

Radiation therapy uses high-energy particles can penetrate the body. Using a machine called a linear accelerator, generate and direct the particles to the particular place where you have to apply. Other areas of the body are protected to not receive radiation.

Radiation therapy uses particles similar to X-rays, which are used to make a radiograph, what happens is that the latter, the quantity supplied is very small.

Cancer cells are especially sensitive to the radiation.

The pathologist will decide the exact area where rays provide. The exact area of the tumor will have been located through diagnostic tests like X-rays, biopsies, etc

Radiation therapy can be used as monotherapy in cases where tumors are particularly sensitive to radiation and no signs of it has spread to anywhere else.

Can be used as supplementary treatment to surgery, to apply prior to this, and to decrease tumor size and is easier to remove.

The joint treatment of radiotherapy and chemotherapy is also used frequently. Sometimes, the use of chemotherapy before radiation makes the cancer cells more radiosensitive. Other radiotherapy is used after chemotherapy to ensure removal of all cancer cells.

The patient will have to go on an outpatient, clinic or hospital where you are given radiotherapy. The duration of each session is about twenty minutes. The patient will be alone in an isolated room so that the radiation does not spread. The areas where you have 

to apply the radiation will be marked and the other will be protected from radiation. After the session, the patient may leave your casa.La chemotherapy is the use of drugs to treat cancer. They are products whose function is to remove, damage or delay the growth of cancer cells

The main issue that causes this treatment is derived from cancer cells are not agents or foreign to the body but are similar to surrounding cells. This makes the drugs, which act primarily against cancer cells, also have effects on normal cells

Chemotherapy

Chemotherapy works on cells that divide rapidly, which is what they usually do cancer cells. But there are other cells which are not cancer and also divide rapidly.

Some chemotherapy drugs work by interrupting the stage where the cancer cell is split and this makes the rise time is greater and the cell dies.

Other drugs involved in all phases of the cell. Because cancer cells are more fragile than normal, are more affected than normal, so the action of drugs is primarily on them.

Other drugs change the external conditions of the organism to which they are unfavorable to the cells. This is the case of hormones that can block the action of certain substances and thus not support the growth of malignant cells.

In recent years, are using combinations of chemotherapeutic agents because it was found that their combined action is more effective to kill cancer.

Anticancer drugs are usually combined with different modes of action and ability to produce different effects.

There is treatment that contain a drug involved in a phase of the cell, other involved in another phase and a hormone that changes in external conditions the cells .

hereditary Diseases

Inherited diseases are genetic diseases that set whose main characteristic is its survival for generations, passed down from father to son and so on.

Monogenic inherited diseases are those caused by the mutation or alteration in the DNA sequence of a single gene. Also called Mendelian inherited diseases, for airing on the offspring according to Mendel's laws. There are more than 6,000 monogenic inherited diseases with a prevalence of one per 200 births. Still, unless you are polygenic diseases.

Monogenic diseases are transmitted according to Mendelian inheritance patterns such as:

Autosomal recessive disease. For the disease to manifest, you need two copies of the mutated gene in the genome of the affected person, whose parents usually do not have the disease, but each carry one copy of the mutated gene, so it can pass on to offspring. It is transmitted by non-sex chromosomes (autosomes). The chance of having a child affected by an autosomal recessive between two people carrying a single copy of the mutated gene (which do not manifest the disease) is 25% ..

Autosomal dominant. You just need a copy of the gene so that the person is affected by an autosomal dominant. Normally one of the parents of an affected person has the disease and these parents have a 50% chance of passing the mutated gene to their offspring, who get the disease.

X-linked disease The mutated gene is located on chromosome X. These diseases can be transmitted in turn in a dominant or recessive.

multifactorial diseases

Polygenic also called, are produced by the combination of environmental factors and multiple mutations in multiple genes, usually from different chromosomes. Not follow a Mendelian inheritance pattern, and sometimes when it is a major gene responsible for the disease behaves as dominant inheritance with incomplete penetrance, as in the case of hereditary breast cancer (BRCA1 and BRCA2 genes). Some of the most common chronic diseases are polygenic, for example, hypertension, Alzheimer's disease, schizophrenia, retinitis pigmentosa, asthma, diabetes mellitus, various cancers, including obesity. Polygenic inheritance is also associated with heritable traits such as fingerprint patterns, height, eye color and skin color. Possibly the most diseases are multifactorial diseases caused by the combination of genetic disorders that predispose to a particular susceptibility to environmental agents

family tree

A family tree is a graph that lists the ancestors and descendants of an individual in an organized and systematic in the form of tree or table. Can be upward, exposing the ancestors or ancestors of a person, or down, exposing all descendants. To make a family tree is necessary first to have conducted a genealogical or pedigree of the individual.

Depending on the purpose or use other choice given to the family tree, it can refer only to male filiation and succession, also called bloodline or lineage, or parentage and female succession, also called the navel line.

The family tree does not apply only in humans and is also used to show the pedigree of an animal, to represent the evolution of a language or language, follow the path of a political party, an art form or a martial art and see the ramifications .

hemophilia

It is an inherited bleeding disorder caused by a lack of blood clotting factor VIII. Without enough of this factor, the blood can not clot properly to stop the bleeding.

Causes, incidence, and risk factors

Hemophilia A is caused by an inherited trait linked recessive X chromosome with the defective gene located on chromosome. Females have two X chromosomes, so that if the factor VIII gene on one chromosome does not work, the gene on the other chromosome can do the job of making enough factor VIII. Men, however, have only one X chromosome, so that if the factor VIII gene on that chromosome is defective, they will have hemophilia A. Therefore, most people with hemophilia A are male.

If a woman has a defective factor VIII gene is considered a carrier, which means you can pass the defective gene to their children. In a woman who carries the defective gene, any of the sons have a 50% chance of having hemophilia A, while any of the daughters have a 50% chance of being a carrier. Also, all the daughters of men with hemophilia carry the defective gene. Genetic testing is available for parents who have any concerns.

Risk factors for hemophilia A include:

Family history of bleeding

To be a man

Rarely, adults can develop a bleeding disorder similar to hemophilia A. This can happen after childbirth (postpartum), in people with certain autoimmune diseases such as rheumatoid arthritis, in people with certain types of cancer (most commonly lymphomas and leukemias) and also for unknown reasons (called "idiopathic"). Although these situations are rare, may be associated with severe bleeding and even life threatening.

symptoms

The severity of symptoms can vary. Bleeding is the main symptom and sometimes, though not always, occurs if an infant is circumcised.

Other bleeding problems are seen when the baby starts crawling and walking.

Mild cases may go unnoticed until later in life when they occur in response to surgery or trauma. Internal bleeding may happen anywhere and is common bleeding into the joints.

Symptoms may include:

Bleeding into joints and associated pain and edema

Blood in the urine or stool

bruising

Urinary tract bleeding and digestive

nosebleeds

Prolonged bleeding from cuts, tooth extraction and surgery

spontaneous bleeding