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Fragile Site
A chromosomal fragile site is a specific heritable point on a chromosome that tends to form a gap or constriction and may tend to break when the cell is exposed to partial replication stress. Based on their frequency, fragile sites are classified as "common" or "rare". To date, more than 120 fragile sites have been identified in the human genome. Common fragile sites are considered part of normal chromosome structure and are present in all (or nearly all) individuals in a population. Under normal conditions, most common fragile sites are not prone to spontaneous breaks. Common fragile sites are of interest in cancer studies because they are frequently affected in cancer and they can be found in healthy individuals. Sites FRA3B (harboring the ''FHIT'' gene) and FRA16D (harboring the ''WWOX'' gene) are two well known examples and have been a major focus of research. Rare fragile sites are found in less than 5% of the population, and are often composed of two- or three-nucleotide re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camptothecin
Camptothecin (CPT) is a topoisomerase inhibitor. It was discovered in 1966 by M. E. Wall and M. C. Wani in systematic screening of natural products for anticancer drugs. It was isolated from the Bark (botany), bark of ''Camptotheca acuminata'' (喜树 "Happy tree"), a tree native to China used in traditional Chinese medicine. It has been used clinically in China for the treatment of gastrointestinal tumors. CPT showed anticancer activity in preliminary clinical trials, especially against breast, ovarian, colon, lung, and stomach cancers. However, it has low solubility and adverse effects have been reported when used therapeutically, so synthetic and medicinal chemists have developed numerous syntheses of camptothecin and various derivatives to increase the benefits of the chemical, with good results. Four CPT Analog (chemistry), analogues have been approved and are used in cancer chemotherapy today: topotecan, irinotecan, belotecan, and trastuzumab deruxtecan. Camptothecin has als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seckel Syndrome
Seckel syndrome, or microcephalic primordial dwarfism (also known as bird-headed dwarfism, Harper's syndrome, Virchow–Seckel dwarfism and bird-headed dwarf of Seckel) is an extremely rare congenital nanosomic disorder. Inheritance is autosomal recessive. It is characterized by intrauterine growth restriction and postnatal dwarfism with a small head, narrow bird-like face with a beak-like nose, large eyes with down-slanting palpebral fissures, receding mandible and intellectual disability. A mouse model has been developed. This mouse model is characterized by a severe deficiency of ATR protein. These mice have high levels of replicative stress and DNA damage. Adult Seckel mice display accelerated aging. These findings are consistent with the DNA damage theory of aging. Symptoms and signs Symptoms include: * intellectual disability (more than half of the patients have an IQ below 50) * microcephaly * sometimes pancytopenia (low blood counts) * cryptorchidism in males * low bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome 11
Chromosome 11 is one of the 23 pairs of chromosomes in humans. Humans normally have two copies of this chromosome. Chromosome 11 spans about 135 million base pairs (the building material of DNA) and represents between 4 and 4.5 percent of the total DNA in cells. The shorter arm (p arm) is termed 11p while the longer arm (q arm) is 11q. At about 21.5 genes per megabase, chromosome 11 is one of the most gene-rich, and disease-rich, chromosomes in the human genome. More than 40% of the 856 olfactory receptor genes in the human genome are located in 28 single-gene and multi-gene clusters along the chromosome. Gene Number of genes The following are some of the gene count estimates of human chromosome 11. Because researchers use different approaches to genome annotation their predictions of the number of genes on each chromosome varies (for technical details, see gene prediction). Among various projects, the collaborative consensus coding sequence project ( CCDS) takes an extremely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jacobsen Syndrome
Jacobsen syndrome is a rare chromosomal disorder resulting from deletion of genes from chromosome 11 that includes band 11q24.1. It is a congenital disorder. Since the deletion takes place on the q arm of chromosome 11, it is also called 11q terminal deletion disorder. The deletion may range from 5 million to 16 million deleted DNA base pairs. The severity of symptoms depends on the number of deletions; the more deletions there are, the more severe the symptoms are likely to be. People with Jacobsen syndrome have serious intellectual disabilities, dysmorphic features, delayed development and a variety of physical problems including heart defects. Research shows that almost 88.5% of people with Jacobsen syndrome have a bleeding disorder called Paris-Trousseau syndrome. Jacobsen syndrome is catastrophic in 1 out of every 5 cases, with children usually dying within the first 2 years of life due to heart complications. Signs and symptoms Almost all children with Jacobsen synd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tumors
A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists in growing abnormally, even if the original trigger is removed. This abnormal growth usually forms a mass, which may be called a tumour or tumor.'' ICD-10 classifies neoplasms into four main groups: benign neoplasms, in situ neoplasms, malignant neoplasms, and neoplasms of uncertain or unknown behavior. Malignant neoplasms are also simply known as cancers and are the focus of oncology. Prior to the abnormal growth of tissue, such as neoplasia, cells often undergo an abnormal pattern of growth, such as metaplasia or dysplasia. However, metaplasia or dysplasia does not always progress to neoplasia and can occur in other conditions as well. The word neoplasm is from Ancient Greek 'new' and 'formation, creation'. Types A neoplas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Papilloma Virus
Human papillomavirus infection (HPV infection) is caused by a DNA virus from the ''Papillomaviridae'' family. Many HPV infections cause no symptoms and 90% resolve spontaneously within two years. In some cases, an HPV infection persists and results in either warts or precancerous lesions. All warts are caused by HPV. These lesions, depending on the site affected, increase the risk of cancer of the cervix, vulva, vagina, penis, anus, mouth, tonsils, or throat. Nearly all cervical cancer is due to HPV, and two strains – HPV16 and HPV18 – account for 70% of all cases. HPV16 is responsible for almost 90% of HPV-positive oropharyngeal cancers. Between 60% and 90% of the other cancers listed above are also linked to HPV. HPV6 and HPV11 are common causes of genital warts and laryngeal papillomatosis. An HPV infection is caused by the ''human papillomavirus'', a DNA virus from the papillomavirus family. Over 200 types have been described. An individual can become infected wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hepatitis B Virus
Hepatitis B virus (HBV) is a partially double-stranded DNA virus, a species of the genus '' Orthohepadnavirus'' and a member of the '' Hepadnaviridae'' family of viruses. This virus causes the disease hepatitis B. Classification Hepatitis B virus is classified in the genus '' Orthohepadnavirus'', which contains 11 other species. The genus is classified as part of the '' Hepadnaviridae'' family, which contains four other genera, '' Avihepadnavirus'', '' Herpetohepadnavirus'', '' Metahepadnavirus'' and '' Parahepadnavirus''. This family of viruses is the only member of the viral order ''Blubervirales''. Viruses similar to hepatitis B have been found in all apes (orangutans, gibbons, bonobos, gorillas and chimpanzees), in Old World monkeys, and in New World woolly monkeys (the woolly monkey hepatitis B virus), suggesting an ancient origin for this virus in primates. The virus is divided into four major serotypes (adr, adw, ayr, ayw) based on antigenic epitopes present on it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MicroRNA
Micro ribonucleic acid (microRNA, miRNA, μRNA) are small, single-stranded, non-coding RNA molecules containing 21–23 nucleotides. Found in plants, animals, and even some viruses, miRNAs are involved in RNA silencing and post-transcriptional regulation of gene expression. miRNAs base-pair to complementary sequences in messenger RNA (mRNA) molecules, then silence said mRNA molecules by one or more of the following processes: * Cleaving the mRNA strand into two pieces. * Destabilizing the mRNA by shortening its poly(A) tail. * Reducing translation of the mRNA into proteins. In cells of humans and other animals, miRNAs primarily act by destabilizing the mRNA. miRNAs resemble the small interfering RNAs (siRNAs) of the RNA interference (RNAi) pathway, except miRNAs derive from regions of RNA transcripts that fold back on themselves to form short stem-loops (hairpins), whereas siRNAs derive from longer regions of double-stranded RNA. The human genome may encode ov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cancer
Cancer is a group of diseases involving Cell growth#Disorders, abnormal cell growth with the potential to Invasion (cancer), invade or Metastasis, spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible Signs and symptoms of cancer, signs and symptoms include a lump, abnormal bleeding, prolonged cough, unexplained weight loss, and a change in defecation, bowel movements. While these symptoms may indicate cancer, they can also have other causes. List of cancer types, Over 100 types of cancers affect humans. Tobacco use is the cause of about 22% of cancer deaths. Another 10% are due to obesity, poor Diet (nutrition), diet, sedentary lifestyle, lack of physical activity or Alcohol abuse, excessive alcohol consumption. Other factors include certain infections, exposure to ionizing radiation, and environmental pollutants. infectious causes of cancer, Infection with specific viruses, bacteria and parasites is an environmental factor cau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
