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Fatty Change
Steatosis, also called fatty change, is abnormal retention of fat (lipids) within a cell or organ. Steatosis most often affects the liver – the primary organ of lipid metabolism – where the condition is commonly referred to as fatty liver disease. Steatosis can also occur in other organs, including the kidneys, heart, and muscle. When the term is not further specified (as, for example, in 'cardiac steatosis'), it is assumed to refer to the liver. Risk factors associated with steatosis are varied, and may include diabetes mellitus, protein malnutrition, hypertension, cell toxins, obesity, anoxia, and sleep apnea. Steatosis reflects an impairment of the normal processes of synthesis and elimination of triglyceride fat. Excess lipid accumulates in vesicles that displace the cytoplasm. When the vesicles are large enough to distort the nucleus, the condition is known as macrovesicular steatosis; otherwise, the condition is known as microvesicular steatosis. While not particularly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Pseudohypertrophy
Pseudohypertrophy, or false enlargement, is an increase in the size of an organ due to infiltration of a tissue not normally found in that organ. It is commonly applied to enlargement of a muscle due to infiltration of fat or connective tissue, famously in Duchenne muscular dystrophy. This is in contrast with typical muscle hypertrophy, in which the muscle tissue itself increases in size. Because pseudohypertrophy is not a result of increased muscle tissue, the muscles look bigger but are actually atrophied and thus weaker. Pseudohypertrophy is typically the result of a disease, which can be a disease of muscle or a disease of the nerve supplying the muscle. Causes of pseudohypertrophy include muscle diseases: dystrophinopathies, limb-girdle muscular dystrophies, metabolic myopathy, Dystrophic myotonias, Non-dystrophic myotonias, endocrine disorders, parasitic muscle conditions, amyloid and sarcoid myopathy, and granulomatous myositis. Neurological causes include radiculopa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Cytoplasm
The cytoplasm describes all the material within a eukaryotic or prokaryotic cell, enclosed by the cell membrane, including the organelles and excluding the nucleus in eukaryotic cells. The material inside the nucleus of a eukaryotic cell and contained within the nuclear membrane is termed the nucleoplasm. The main components of the cytoplasm are the cytosol (a gel-like substance), the cell's internal sub-structures, and various cytoplasmic inclusions. In eukaryotes the cytoplasm also includes the nucleus, and other membrane-bound organelles.The cytoplasm is about 80% water and is usually colorless. The submicroscopic ground cell substance, or cytoplasmic matrix, that remains after the exclusion of the cell organelles and particles is groundplasm. It is the hyaloplasm of light microscopy, a highly complex, polyphasic system in which all resolvable cytoplasmic elements are suspended, including the larger organelles such as the ribosomes, mitochondria, plant plasti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Adipocyte
Adipocytes, also known as lipocytes and fat cells, are the cell (biology), cells that primarily compose adipose tissue, specialized in storing energy as fat. Adipocytes are derived from mesenchymal stem cells which give rise to adipocytes through adipogenesis. In cell culture, adipocyte progenitors can also form osteoblasts, myocytes and other cell types. There are two types of adipose tissue, white adipose tissue (WAT) and brown adipose tissue (BAT), which are also known as white and brown fat, respectively, and comprise two types of fat cells. Structure White fat cells White fat cells contain a single large lipid droplet surrounded by a layer of cytoplasm, and are known as unilocular. The Cell nucleus, nucleus is flattened and pushed to the periphery. A typical fat cell is 0.1 mm in diameter with some being twice that size, and others half that size. However, these numerical estimates of fat cell size depend largely on the measurement method and the location of the adi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Alcoholism
Alcoholism is the continued drinking of alcohol despite it causing problems. Some definitions require evidence of dependence and withdrawal. Problematic use of alcohol has been mentioned in the earliest historical records. The World Health Organization (WHO) estimated there were 283 million people with alcohol use disorders worldwide . The term ''alcoholism'' was first coined in 1852, but ''alcoholism'' and ''alcoholic'' are considered stigmatizing and likely to discourage seeking treatment, so diagnostic terms such as ''alcohol use disorder'' and ''alcohol dependence'' are often used instead in a clinical context. Alcohol is addictive, and heavy long-term alcohol use results in many negative health and social consequences. It can damage all the organ systems, but especially affects the brain, heart, liver, pancreas, and immune system. Heavy alcohol usage can result in trouble sleeping, and severe cognitive issues like dementia, brain damage, or Wernicke–Kors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Obstructive Sleep Apnea
Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is characterized by recurrent episodes of complete or partial airway obstruction, obstruction of the respiratory tract#Upper respiratory tract, upper airway leading to reduced or absent breathing during sleep. These episodes are termed "apneas" with complete or near-complete cessation of breathing, or "hypopneas" when the reduction in breathing is partial. In either case, a fall in oxygen saturation (medicine), blood oxygen saturation, a disruption in sleep, or both, may result. A high frequency of apneas or hypopneas during sleep may interfere with the quality of sleep, whichin combination with disturbances in blood oxygenationis thought to contribute to negative consequences to health and quality of life. The terms obstructive sleep apnea syndrome (OSAS) or obstructive sleep apnea–hypopnea syndrome (OSAHS) may be used to refer to OSA when it is associated with symptoms during the daytime (e.g. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Lipoprotein
A lipoprotein is a biochemical assembly whose primary function is to transport hydrophobic lipid (also known as fat) molecules in water, as in blood plasma or other extracellular fluids. They consist of a triglyceride and cholesterol center, surrounded by a phospholipid outer shell, with the hydrophilic portions oriented outward toward the surrounding water and lipophilic portions oriented inward toward the lipid center. A special kind of protein, called apolipoprotein, is embedded in the outer shell, both stabilising the complex and giving it a functional identity that determines its role. Plasma lipoprotein particles are commonly divided into five main classes, based on size, lipid composition, and apolipoprotein content. They are, in increasing size order: HDL, LDL, IDL, VLDL and chylomicrons. Subgroups of these plasma particles are primary drivers or modulators of atherosclerosis. Many enzymes, transporters, structural proteins, antigens, adhesins, and toxins are some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Apolipoprotein
Apolipoproteins are proteins that bind lipids (oil-soluble substances such as fats, cholesterol and fat soluble vitamins) to form lipoproteins. They transport lipids in blood, cerebrospinal fluid and lymph. The lipid components of lipoproteins are insoluble in water. However, because of their detergent-like ( amphipathic) properties, apolipoproteins and other amphipathic molecules (such as phospholipids) can surround the lipids, creating a lipoprotein particle that is itself water-soluble, and can thus be carried through body fluids (i.e., blood, lymph). In addition to stabilizing lipoprotein structure and solubilizing the lipid component, apolipoproteins interact with lipoprotein receptors and lipid transport proteins, thereby participating in lipoprotein uptake and clearance. They also serve as enzyme cofactors for specific enzymes involved in the metabolism of lipoproteins. Apolipoproteins are also exploited by hepatitis C virus (HCV) to enable virus entry, assembly, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Kwashiorkor
Kwashiorkor ( , is also ) is a form of severe protein malnutrition characterized by edema and an enlarged liver with fatty infiltrates. It is thought to be caused by sufficient calorie intake, but with insufficient protein consumption (or lack of good quality protein), which distinguishes it from marasmus. Recent studies have found that a lack of antioxidant micronutrients such as β-carotene, lycopene, other carotenoids, and vitamin C as well as the presence of aflatoxins may play a role in the development of the disease. However, the exact cause of kwashiorkor is still unknown. Inadequate food supply is correlated with kwashiorkor; occurrences in high-income countries are rare. It occurs amongst weaning children to ages of about five years old. Conditions analogous to kwashiorkor were well documented around the world throughout history. The disease's first formal description was published by Jamaican pediatrician Cicely Williams in 1933. She was the first to researc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Glycolipid
Glycolipids () are lipids with a carbohydrate attached by a glycosidic (covalent) bond. Their role is to maintain the stability of the cell membrane and to facilitate cellular recognition, which is crucial to the immune response and in the connections that allow cells to connect to one another to form tissues. Glycolipids are found on the surface of all eukaryotic cell membranes, where they extend from the phospholipid bilayer into the extracellular environment. Structure The essential feature of a glycolipid is the presence of a monosaccharide or oligosaccharide bound to a lipid moiety. The most common lipids in cellular membranes are glycerolipids and sphingolipids, which have glycerol or a sphingosine backbones, respectively. Fatty acids are connected to this backbone, so that the lipid as a whole has a polar head and a non-polar tail. The lipid bilayer of the cell membrane consists of two layers of lipids, with the inner and outer surfaces of the membrane made up o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Lysosome
A lysosome () is a membrane-bound organelle that is found in all mammalian cells, with the exception of red blood cells (erythrocytes). There are normally hundreds of lysosomes in the cytosol, where they function as the cell’s degradation center. Their primary responsibility is catabolic degradation of proteins, polysaccharides and lipids into their respective building-block molecules: amino acids, monosaccharides, and free fatty acids. The breakdown is done by various enzymes, for example proteases, glycosidases and lipases. With an acidic lumen limited by a single-bilayer lipid membrane, the lysosome holds an environment isolated from the rest of the cell. The lower pH creates optimal conditions for the over 60 different Hydrolase, hydrolases inside. Lysosomes receive extracellular particles through endocytosis, and intracellular components through autophagy. They can also fuse with the plasma membrane and secrete their contents, a process called lysosomal exocytosis. After ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Gaucher's Disease
Gaucher's disease or Gaucher disease () (GD) is a genetic disorder in which glucocerebroside (a sphingolipid, also known as glucosylceramide) accumulates in cells and certain organs. The disorder is characterized by bruising, fatigue, anemia, low blood platelet count and enlargement of the liver and spleen, and is caused by a hereditary deficiency of the enzyme glucocerebrosidase (also known as glucosylceramidase), which acts on glucocerebroside. When the enzyme is defective, glucocerebroside accumulates, particularly in white blood cells and especially in macrophages ( mononuclear leukocytes, which is often a target for intracellular parasites). Glucocerebroside can collect in the spleen, liver, kidneys, lungs, brain, and bone marrow. Manifestations may include enlarged spleen and liver, liver malfunction, skeletal disorders or bone lesions that may be painful, severe neurological complications, swelling of lymph nodes and (occasionally) adjacent joints, distended abdomen, a b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Diphtheria Toxin
Diphtheria toxin is an exotoxin secreted mainly by '' Corynebacterium diphtheriae'' but also by ''Corynebacterium ulcerans'' and '' Corynebacterium pseudotuberculosis'', the pathogenic bacterium that causes diphtheria. The toxin gene is encoded by a prophageA prophage is a virus that has inserted itself into the genome of the host bacterium. called corynephage β. The toxin causes the disease in humans by gaining entry into the cell cytoplasm and inhibiting protein synthesis. Structure Diphtheria toxin is a single polypeptide chain of 535 amino acids consisting of two subunits linked by disulfide bridges, known as an A-B toxin. Binding to the cell surface of the B subunit (the less stable of the two subunits) allows the A subunit (the more stable part of the protein) to penetrate the host cell. The crystal structure of the diphtheria toxin homodimer has been determined to 2.5 Ångstrom resolution. The structure reveals a Y-shaped molecule consisting of three domain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
