BIOTECHNOLOGY

Biotechnology is a field of applied biology that involves the use of living organisms and bioprocesses in engineering, technology, medicine and other fields requiring bioproducts.Biotechnology also utilizes these products for manufacturing purpose. Modern use of similar terms includes genetic engineering as well as cell- and tissue culture technologies. The concept encompasses a wide range of procedures (and history) for modifying living organisms according to human purposes - going back to domestication of animals, cultivation of plants, and "improvements" to these through breeding programs that employ artificial selection and hybridization. By comparison to biotechnology, bioengineering is generally...

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Sexual activity during pregnancy

Most pregnant women can enjoy sexual activity during pregnancy throughout gravidity. Most research suggests that, during pregnancy, both sexual desire and frequency of sexual relations decrease.[75][76] In context of this overall decrease in desire, some studies indicate a second-trimester increase, preceding a decrease.[77][78] However, these decreases are not universal: a significant number of women report greater sexual satisfaction throughout their pregnanci...

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medicine which used during Pregnancy

Drugs used during pregnancy can have temporary or permanent effects on the fetus. Therefore many physicians would prefer not to prescribe for pregnant women, the major concern being over teratogenicity of the drugs.Drugs have been classified into categories A,B,C,D and X based on the Food and Drug Administration (FDA) rating system to provide therapeutic guidance based on potential benefits and fetal risks. Drugs like multivitaminsthalidomide with proven fetal risks that outweigh all benefits are classified as Category X that have demonstrated no fetal risks after controlled studies in humans are classified as Category A. On the other hand drugs like...

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Physiological changes of Pregnancy

During pregnancy, the woman undergoes many physiological changes, which are entirely normal, including cardiovascular, hematologic, metabolic, renal and respiratory changes that become very important in the event of complications. The body must change its physiological and homeostatic mechanisms in pregnancy to ensure the fetus is provided for. Increases in blood sugar, breathing and cardiac output are all required. Levels of progesterone and oestrogens rise continually throughout pregnancy, suppressing the hypothalamic axis and subsequently the menstrual cycle. The woman and the placenta also produce many hormon...

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Embryonic and fetal development of Pregnancy

Prenatal development is divided into two primary biological stages. The first is the embryonic stage, which lasts for about two months. At this point, the fetal stage begins. At the beginning of the fetal stage, the risk of miscarriage decreases sharply,[36] all major structures including the head, brain, hands, feet, and other organs are present, and they continue to grow and develop. When the fetal stage commences, a fetus is typically about 30 mm (1.2 inches) in length, and the heart can be seen beating via sonograph; the fetus bends the head, and also makes general movements and startles that involve the whole body.[37] Some...

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Third Trimester of Pregnancy

Final weight gain takes place, which is the most weight gain throughout the pregnancy. The fetus will be growing the most rapidly during this stage, gaining up to 28 g per day. The woman's belly will transform in shape as the belly drops due to the fetus turning in a downward position ready for birth. During the second trimester, the woman's belly would have been very upright, whereas in the third trimester it will drop down quite low, and the woman will be able to lift her belly up and down. The fetus begins to move regularly, and is felt by the woman. Fetal movement can become quite strong and be disruptive to the woman. The woman's...

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Second Trimester of Pregnancy

Weeks 13 to 28 of the pregnancy are called the second trimester. Most women feel more energized in this period, and begin to put on weight as the symptoms of morning sickness subside and eventually fade away. In the 20th week, the uterus, the muscular organ that holds the developing fetus, can expand up to 20 times its normal size during pregnancy. Although the fetus begins to move and takes a recognizable human shape during the first trimester, it is not until the second trimester that movement of the fetus, often referred to as "quickening", can be felt. This typically happens in the fourth month, more specifically in the 20th to 21st week, or by the 19th week if the woman has been pregnant before. However, it is not uncommon for some women not to feel the fetus move until much...

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First trimester of Pregnancy

First trimester Traditionally, doctors have measured pregnancy from a number of convenient points, including the day of last menstruation, ovulation, fertilization, implantation and chemical detection. In medicine, pregnancy is often defined as beginning when the developing embryo becomes implanted into the endometrial lining of a woman's uterus. In some cases where complications may have arisen, the fertilized egg might implant itself in the fallopian tubes, the cervix, the ovary or in the abdomen causing an ectopic pregnancy. In the case of an ectopic pregnancy there is no way for the pregnancy to progress normally. If left untreated, it can cause harm and possibly death for the mother when a rupture occurs. Sometimes it will go away on its own but otherwise a surgical procedure or...

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Child Birth

Childbirth is the process whereby an infant is born. It is considered by many[who?] to be the beginning of the infant's life, and age is defined relative to this event in most cultures. A woman is considered to be in labour when she begins experiencing regular uterine contractions, accompanied by changes of her cervix — primarily effacement and dilation. While childbirth is widely experienced as painful, some women do report painless labours, while others find that concentrating on the birth helps to quicken labour and lessen the sensations. Most births are successful vaginal births, but sometimes complications arise and a woman may undergo a cesarean section. During the time immediately after birth, both the mother and the baby are hormonally cued to bond, the mother through the release...

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Duration of Pregnancy

The expected date of delivery (EDD) is 40 weeks counting from the first day of the last menstrual period[13] The actual pregnancy duration is typically 38 weeks after conception. Though pregnancy begins at conception, it is more convenient to date from the first day of a woman's last menstrual period, or from the date of conception if known. Starting from one of these dates, the expected date of delivery can be calculated using the Naegele's rule for estimating date of delivery. A more accurate and sophisticated algorithm takes into account other variables, such as whether this is the first or subsequent child (i.e., pregnant woman is a primip or a multip, respectively), ethnicity, parental age, length of menstrual cycle, and menstrual regularity. (LMP), and birth usually occurs...

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prenetal Period

Prenatal defines the period occurring "around the time of birth", specifically from 22 completed weeks (154 days) of gestation (the time when birth weight is normally 500 g) to 7 completed days after birth.[12]Legal regulations in different countries include gestation age beginning from 16 to 22 weeks (5 months) before birth. The perinatal period is immediately before to after birth. Depending on the definition, it starts between the 20th to 28th week of gestation and ends between 1 to 4 weeks after birth (the word "perinatal" is a hybrid of the Greek "peri-" meaning 'around or about' and "natal" from the Latin "natus" meaning "birth.")....

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What is Pregnancy ?

Pregnancy is the carrying of one or more offspring, known as a fetus or embryo, inside the womb of a female. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets. Human pregnancy is the most studied of all mammalian pregnancies. Childbirth usually occurs about 38 weeks after conception; in women who have a menstrual cycle length of four weeks, this is approximately 40 weeks from the last normal menstrual period (LNMP). The World Health Organization defines normal term for delivery as between 37 weeks and 42 wee...

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A World Without Sex?

The birth of Louise, whose twentieth birthday was celebrated in Britain with great fanfare, excited fears and controversy similar to those surrounding cloning (see Genetic Engineering). As with cloning, the fear was that the technology of in vitro fertilization would lead to the depersonalized manufacturing of human beings associated with some nightmarish future society, but this has not come to pass for several reasons. One is that in vitro fertilization is successful only about 15% of the time. Another, much more significant reason is that there are few women capable of producing a child through internal fertilization who would want to conceive without the intimacy of sexual intercourse.There are exceptions, of course, in real life (two women in a same-sex relationship who want...

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External Fertilization

Most land animals use some form of internal fertilization similar to that which we have described for humans. External fertilization, on the other hand, is more common among aquatic animals, who simply dump their sperm and eggs into the water and let currents mix the two male and female cells together. The sea urchin is a typical example: a male sea urchin releases several billion sperm into the water, and these sperm then swim toward eggs released in the same area. Fertilization occurs within seconds when sperm come into contact and fuse with eggs. As noted in Reproduction, external fertilization is essentially sexual reproduction without sexual intercourse. For humans the process of reproduction by external means may lack the intimacy of internal reproduction, but since 1978...

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The Ovaries and Menstruation

Eggs are produced in the ovaries, oval-shaped organs in the groin that also generate sex hormones. At birth, a female's ovaries contain hundreds of thousands of undeveloped eggs, each surrounded by a group of cells to form a follicle, or sac; however, only about 360-480 follicles reach full maturity. During puberty the action of hormones causes several follicles to develop each month. Normally, just one follicle fully matures, rupturing and releasing an ovum through the ovary wall in a process called ovulation. The mature egg enters one of the paired fallopian tubes, where it may be fertilized by a sperm and move on to the uterus to develop into a fetus. The lining of the uterus, called the endometrium, prepares for pregnancy each month by thickening, but if fertilization does not...

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The Reproductive System

The contrast between sexual and asexual reproduction is examined in Reproduction, an essay that also provides examples of plant reproduction through pollination. The present essay is concerned primarily with human sexual reproduction and secondarily with animal sexual reproduction. Some technical aspects of reproduction at the cellular level require consultation of processes explained in Genetics; here we confine our technical discussion to reproduction at the level of organs, fluids, and other bodily components. Reproduction is facilitated by the reproductive system, a group of organized structures that can be subdivided into male and female reproductive systems. During puberty, which typically occurs between the ages of 10 and 14 years, the reproductive systems of both sexes mature....

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Why Sexual Reproduction?

When Maynard Smith reverse-engineered sex... he created a paradox. Sex should not exist; natural selection will favor asexual reproduction. The solution to the paradox is almost the Holy Grail of a large theoretical sub-branch of evolutionary biology, but it still has not been satisfactorily tracked down. — Mark Ridley, 1997 (1) In spite of the number of ways bacteria can exchange genetic instructions, many of them haven't evolved very far — not as bacteria anyway. There are many modern bacteria that look very similar to fossils of the earliest bacteria of over 3 billion years ago. Eukaryotes are much better at evolving than prokaryotes. Eukaryotes first appeared on Earth about 1.7 billion years ago. They contain complex subunits, some of which — mitochondria and plastids — have...

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SEXUAL REPRODUCTION IN FISH

The vast majority of fish species lay eggs that are then fertilized by the male,[6] some species lay their eggs on a substrate like a rock or on plants, while others scatter their eggs and the eggs are fertilized as they drift or sink in the water column. Some fish species use internal fertilization and then disperse the developing eggs or give birth to live offspring. Fish that have live-bearing offspring include the Guppy and Mollies or Poecilia. Fishes that give birth to live young can be ovoviviparous, where the eggs are fertilized within the female and the eggs simply hatch within the female body, or in seahorses, the male carries the developing young within a pouch, and gives birth to live young.[7] Fishes can also be viviparous, where the female supplies nourishment to the internally...

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FEMALE REPRODUCTIVE SYSTEM

The female reproductive system likewise contains two main divisions: the vagina and uterus, which act as the receptacle for the sperm, and the ovaries, which produce the female's ova. All of these parts are always internal. The vagina is attached to the uterus through the cervix, while the uterus is attached to the ovaries via the Fallopian tubes. At certain intervals, the ovaries release an ovum, which passes through the fallopian tube into the uterus.If, in this transit, it meets with sperm, the egg selects sperm with which to merge; this is termed fertilization. The fertilization usually occurs in the oviducts, but can happen in the uterus itself. The zygote then implantsembryogenesis and morphogenesis. When developed enough to survive outside the womb, the cervix dilates and contractions...

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MALE REPRODUCTIVE SYSTEM

The male reproductive system contains two main divisions: the penis, and the testicles, the latter of which is where sperm are produced. In humans, both of these organs are outside the abdominal cavity, but they can be primarily housed within the abdomen in other animals (for instance, in dogs, the penis is internal except when mating). Having the testicles outside the abdomen best facilitates temperature regulation of the sperm, which require specific temperatures to survive. Sperm are the smaller of the two gametes and are generally very short-lived, requiring males to produce them continuously from the time of sexual maturity until death. Prior to ejaculation the produced sperm are stored in the epididymis. The sperm cells are motile and they swim using tail-like flagella to propel...

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SEXUAL REPRODUCTION IN INSECTS

Insect species make up more than two-thirds of all extant animal species, and most insect species use sex for reproduction, though some species are facultatively parthenogenetic. Many species have sexual dimorphism, while in others the sexes look nearly identical. Typically they have two sexes with males producing spermatozoa and females ova. The ova develop into eggs that have a covering called the chorion, which forms before internal fertilization. Insects have very diverse mating and reproductive strategies most often resulting in the male depositing spermatophore within the female, which stores the sperm until she is ready for egg fertilization. After fertilization, and the formation of a zygote, and varying degrees of development; the eggs are deposited outside the female in...

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SEXUAL REPRODUCTION OF HUMAN BEINGS

Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. The two main processes are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the restoration of the original number of chromosomes. During meiosis, the chromosomes of each pair usually cross over to achieve homologous recombination. The evolution of sexual reproduction is a major puzzle. The first fossilized evidence of sexually reproducing organisms is from eukaryotes of the Stenian period, about 1 to 1.2 billion years ago.[1] Sexual reproduction is the primary method of reproduction for the vast majority of macroscopic organisms, including almost all animals and plants. Bacterial conjugation, the transfer of DNA between...

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RADIATION TREATMENT FOR BRAIN TUMOR....!

The goal of radiation therapy is to selectively kill tumor cells while leaving normal brain tissue unharmed. In standard external beam radiation therapy, multiple treatments of standard-dose "fractions" of radiation are applied to the brain. Each treatment induces damage to both healthy and normal tissue. By the time the next treatment is given, most of the normal cells have repaired the damage, but the tumor tissue has not. This process is repeated for a total of 10 to 30 treatments, depending on the type of tumor. This additional treatment provides some patients with improved outcomes and longer survival rates.Radiosurgery is a treatment method that uses computerized calculations to focus radiation at the site of the tumor while minimizing the radiation dose to the surrounding...

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SURGERIES FOR BRAIN TUMOR'S

The primary course of action described in medical literature is surgical removal (ressection), a craniotomy(to open the skull) to best access the tumor site, currently minimal invasive techniques are being studied but far from being common practice. The prime re mediating objective of surgery is to remove as many tumor cells as possible, in any case surgery will reduce the tumor size and will attempt to completely remove the neoplasm. In some cases access to the tumor is impossible and impedes surgery.Many meningiomas, with the exception of some tumors located at the skull base, can be successfully removed surgically. Most can be removed surgically, often using a minimally invasive approach through the nasal cavity and skull base (trans-nasal, trans-sphenoidal approach). Large pituitary...

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Diagnosis

Although there is no specific or singular clinical symptom or sign for any brain tumors, the presence of a combination of symptoms and the lack of corresponding clinical indications of infections might be an indicator to step up the diagnostic investigation to the direction of an intracranial neoplasm. The diagnosis will often start with an interrogation of the patient to get a clear view of his medical antecedents, and his current symptoms. Clinical and laboratory investigations will serve to exclude infections as cause of the symptoms. Examinations in this stage may include ophtamological, otolaryngological (or ENT) and/or Electrophysiological...

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Characterstics of tumors

Tumors have characteristics that allow pathologists to determine how dangerous a tumor is/was for the patient, how it will evolve and it will allow the medical team to determine the management plan for the patient. Anaplasia: or dedifferentiation; loss of differentiation of cells and of their orientation to one another and blood vessels, a characteristic of anaplastic tumor tissue. Anaplastic cells have lost total control of their normal functions and many have deteriorated cell structures. Anaplastic cells often have abnormally high nuclear-to-cytoplasmic ratios, and many are multinucleated. Additionally, the nuclei of anaplastic cells are usually unnaturally shaped or oversized nuclei. Cells can become anaplastic in two ways: neoplastic tumor cells can dedifferentiate to become...

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BRAIN TUMOR...........!

Symptoms & Diagnosis A brain tumor takes up space within the skull and can interfere with normal brain activity. It can increase pressure in the brain, shift the brain or push it against the skull, and/or invade and damage nerves and healthy brain tissue. The location of a brain tumor influences the type of symptoms that occur. Identifying the presence of a brain tumor is the first step in determining a course of treatment. Click on a question from the list below to learn more about the process of diagnosing a brain tumor: What are the symptoms of a brain tumor? How is a brain tumor diagnosed? What else should I know about diagnostic tests? How is a pathology report used to diagnose brain tumors? How can I find out more about the location and type of tumor in my brain? ...

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