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Cell biology progressed in the second half of the 20th century, providing a much deeper insight of both normal and anomalous conditions in the body. The availability of electron microscopes make possible to examine to the structures and the components of the cell, and chemical exploration revealed evidences to their functions and complex metabolism in the cells. The introduction of tissue culture also helps to growing viruses in the laboratory atmosphere. It led to the fast growth in progress of effective viral vaccines. Microbiologist Max Theiler developed the first viral vaccine for yellow fever in the late 1930s [57]. The first comparatively efficient vaccine for influenza was produced around 1945 [58]. In the 1950s and 1960s, polio, measles, and rubella vaccines were developed by American physician Jonas Salk in 1954; and in 1960, an oral polio vaccine was developed by virologist Albert Sabin which helped wipe out polio from the western world in the 20* century, and which may help to make the eradication of polio worldwide in 21s' century [59]. Effective vaccines for measles and rubella (German measles) were used during the 1960s. A better measles vaccine was developed in 1968. More vaccines have been created to control illnesses of the childhood. Children’s health was usually better after the war [60].


The study of endocrine functions in its modem foim was implemented in the latter half of the nineteenth and the first decades of the twentieth century [61].

Endocrinology is the study of disorders on endocrine system. It helps to diagnose a wide range of symptoms and variants and the management of disorders by the deficiency or excess of one or more hormones in fact, the key events that led to identification of endocrine functions took place between 1890 and 1905, in this period, and word “hormone” began to be institutionalized. Secretin, a chemical messenger secreted by the intestinal mucosa, was found in 1902 by Bayliss and Starling [62]. For this class of internal secretions, Earnest Starling and Edward Sharpey-Schafer (1905) proposed the name “hormone.” Endocrinology was introduced as a fresh scientific branch [63]. English physician George Redmayne Murray was effectively treated myxedema by using thyroid gland extract (1891). Sharpey-Schafer and George Oliver later identified the substance found in the adrenal gland extracts [Adrenaline, also called epinephrine] which was the cause of high blood pressure [64]. In 1901, Jokichi Takamine, a Japanese chemist isolated the adrenaline [65].


Dr. Robert Edwards and Dr. Patrick Steptoe perform effective IVF treatment in England for the first tune in November 1977. Eggs are collected from Lesley Brown and fertilized with sperm samples from John Brown [66]. Today, IVF is considered a medical procedure for infertility. In some instances, children have been conceived with donor eggs and sperm. An approximately 6.5 million IVF-conceived kids were bom across the world. These babies of the so-called test tube are as healthy and normal as kids that are typically conceived.


In the 20th century, both chemotherapy and radiotherapy were developed as treatments for cancer. Before the development of these treatments, the large number of individuals who have cancer died of the disease.

1.10.1 SURGERY

The discoveiy of general anesthesia in the mid of the 19th century commences a golden age of surgical imiovation. In 1880s. an American surgeon William Halsted pioneered radical cancer operations. The radical surgery proved that surgeons could remove cancers. The first radical mastectomy to treat breast cancer was conducted by Halsted. This surgical procedure remained as the normal surgery for breast cancer treatment until the latter half of the 20th century [67]. The surgeries have limitations in some cases as, if the tumor has initiated to spread or the tumors are at inaccessible sites.


S.W. Goldberg and Efim (London) used radiation therapy for cancer treatment for the first time (1903). They used radium to treat two skin basal cell carcinoma patients and in both patients, the disease was eradicated. Radiation therapy can be used to treat nearly all types of solid tumors, including the brain, breast, cervix, larynx, liver, lung, pancreas, prostate, skin, stomach, uterus, or soft tissue sarcomas, leukemia, and lymphoma [68]. The dose of radiation at each site depends on several factors of factors, including the radiosensitivity of each type of cancer and surrounding tissues or organs, etc., radiation therapy eliminates cancer cells by damaging their DNA (deoxyribonucleic acid). The significant benefits of radiotherapy have facilitated the implementation of modem, sophisticated methods for treatment, therapy, delivery, and imaging to be executed into regular radiation oncology practice.


At the beginning of the 20th century, chemotherapy was first developed, although it was not originally intended as a treatment for cancer. It was found during the Second World War that individuals exposed to nitrogen mustard had a considerably decreased number of white blood cells (WBC) [68]. This finding prompted scientists to explore the possibility of using mustard agents to avoid the development of rapidly dividing cells such as cancer cells. This discoveiy dramatically altered the scientific opinion and marked a turning point for cancer research until the researchers presumed that cancer-induced by acting on proteins rather than genes was caused by cancer. In 1949, the US Food and Drug Administration approved the nitrogen mustard as the first chemotherapeutic drug (mechlorethamine) for cancer treatment. Nitrogen mustard have a capacity to alkylate molecules including protein, DNA, and RNA, thus it belongs to the class of drugs called alkylating agents. It facilitates to destroy the cancer cells by chemically modifying their DNA. It promotes the destruction of cancer cells by altering their DNA chemically. In 1953, Roy Hertz and Min Chiu Li succeeded the first complete curing of a human solid tumor by using the drug Methotrexate [70]. Chemotherapy has the ability to harm surrounding healthy tissues, many of the chemotherapy side effects can be attributed to damage to cells that divide rapidly and these anti-mitotic drugs are sensitive to bone marrow cells, digestive tract, and hair follicles. Radiation may cause damages to these tissues. This results in the most prevalent side effects of chemotherapy such as mucositis with immunosuppression (inflammation of the digestive tract lining), hair loss, and autoimmune illnesses including rheumatoid arthritis, systemic lupus erythematosus, various sclerosis, vasculitis, and many others. The primary limitations of chemotherapy are the high toxicity and often does not destroy complete tumor, thus the chance recurrence is high. Researchers also developed chemotherapy by the mid-20,h century, and is still used today.


Targeted therapy another mode of cancer treatment it primarily assisted with is a drug. But it is distinct from traditional chemotherapy [71]. Targeted therapy operates by targeting the particular genes, proteins, or tissue environment of the cancer that contribute to the development and survival of cancer. These genes and proteins are discovered in cancer cells or cancer growth-related cells. Molecularly targeted therapy has enabling cancer cells to be destroyed and stopping the proliferation of tumor while saving healthy cells [72].


DNA is the genetic sequence that drives the function of the cell and ultimately distinguishes between one life type and another. In the 1950s, Watson, and Crick discovered the DNA structure, medical science opened up new possibilities for all forms of life [73]. Each piece of DNA includes enormous quantities of data. Advanced computer technology permits the DNA codes of human and other life forms to be stored, organized, retrieved, and analyzed. Since this discoveiy, which laid the foundation for molecular biology, many research areas have changed significantly with new insights and developments and also found their way into our daily lives such as DNA sequencing, genetic fingerprinting, or personalized medicine. However, new sequencing techniques have opened up significant opportunities, especially in the field of medicine.

Genomic medicine has already demonstrated its benefit in cancer diagnosis and directing therapeutic approaches. Since the late 1990s, the cancer treatments including surgery, radiation, and chemotherapy has increasingly been supplemented by therapies aimed at specific molecular pathways in cancer growth and development [74]. Genomic information can now help clinicians to decide treatment strategies by classifying a tumor according to its mutations and related sensitivities to drugs. In some cases, patients were spared expensive and complex procedures based on a molecular diagnosis, such as bone marrow transplants. The genetic features may have an enormous impact on the effectiveness of anti-cancer drugs. More popularly, physicians are starting to use genomic data to refine cancer diagnosis and prognosis and improve the of life quality of person [75]. This technology allows the detection and monitoring of non-invasive tumor responses to therapy that assure an extensive improvement in patient management. In the late 1990s, The Human Genome Project (HGP) The HGP was started to record the pattern of coding for a sequence of human DNA; however, by the turn of the century it was not completed.


Development in the modern surgeiy was mainly based on the discovery of anesthesia, anti-septic, and a-septic practices. The introduction of intravenous injection agents such as barbiturates helps the patient to sleep rapidly without any obnoxious inhalation agents. Then in the 1940s and early 1950s the introduced muscle relaxants with curare in the initial period and then over the next decades, up an entire series of other agents. Halothane came in the mid-1950s, which was a revolutionary inhalation agent that was much easier to use. All of these groups of drugs have since been refined so there are now much more potent and less toxic intravenous agents, inhalational agents, local anesthetics, and muscle relaxants. Anesthesia has become veiy secure, and the death rate is veiy less [1 in 250,000]. However, with current highly advanced monitoring systems and a better understanding of body functions, will makes an improvement in this field. The major benefits of anesthesia are the accuracy of surgical procedures, including complex operations; it also helps to make surgeries more common.


Major developments in plastic surgery did not take place before the 20th century, when victims of war, especially soldiers, had to perform plastic surgeiy. Indeed, it was the First World War that brought plastic surgery to a unique level in the medical field. Soldiers injured with a number of extensive facial and head injuries induced by modern weapons had to be treated by military doctors. These serious wounds required new innovations in reconstructive surgery. The history of modern plastic surgery was commenced in 1960s and 1970s [76].

During this tune, there have also been many important scientific developments. Silicone was a novel substance created at that period and it become more popular as a key ingredient of some plastic surgery procedure. It was initially used to treat defects of the skin. Now they are used as implants. In the 2000s, popularity of cosmetic surgeiy enhanced, and medical advances have made greatest achievements in plastic surgery, especially in reconstructive or cosmetic surgical treatment. Currently, the most significant trend in plastic surgery is the less invasive processes to eliminate the visible signs of aging.


Scientists had to wait until the 19* and 20th centuries to perform successful organ transplants by the science and surgical techniques that made modern transplant medicine possible. Between 1900 and 1920, successful bone, skin, and cornea transplantation took place. The progresses in the transplantation of solid organs were started in the 1950s. The kidney was the first organ to be transplanted effectively in humans. Dr. Joseph E Murray [Peter Brent Brigham Hospital, Boston, Massachusetts], The first effective kidney transplant between the identical twins was carried out in 1954 and Dr. Joseph E Murray received the Nobel Prize in Medicine in 1990 [78].

In the late 1960s, liver, heart, and pancreas transplantations were successfully performed, while in the 1980s lung and intestinal transplanting surgeries were started. The main problem was the body’s tendency to activate the immune system against the “foreign” organ [rejection]. Patients were given strong medicines to restrain their whole immune system in order to prevent rejection, which may cause them life-threatening infections. Transplantation surgeries were restricted until around the early 1980s due to difficulties with organ rejection. Presently, kidney, liver, pancreas, lungs, heart, intestines, bone marrow and bones, corneas, skin, and heart valves are being transplanted.

A South African surgeon. Dr. Christian Barnard (1922-2001) transplanted a human heart from one person into another’s body in 1967 at Cape Town. This first experience of clinical heart transplantation stimulated worldwide publicity and the procedure was rapidly co-opted by many surgeons. However, many patients died soon after the surgery, the number of cardiac transplants fell from 100 in 1968 to 18 in 1970 [79]. The main issue in the case of transplantation surgery was the normal tendency of the body to reject the new tissues. Significant developments in tissue typing and immunosuppressive drugs over the next 20 years have enabled more transplant procedures and enhanced recipient survival rates. In 1983, the Columbia University Medical Center launched clinical trials with cyclosporine-an immunosuppressive drugs originating from soil fungus (Discovered by Jean Borel in 1970) which was approved for commercial use (November 1983) and it is the most frequently prescribed immunosuppressant in organ transplantation [80]. When Cyclosporin was introduced as an immunosuppressive drug, many of the rejection problems were controlled. Advanced medical technology prevents organ rejection, has led to more efficient transplantation and increased demand.

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