Persius/hicric huggingface dataset:
Schmorl's nodes

# Overview
Schmorl's nodes are protrusions of the cartilage of the intervertebral disc through the vertebral body endplate and into the adjacent vertebra. 

# Presentation
The protrusions may contact the marrow of the vertebra, leading to inflammation. The protrusions are also associated with necrosis of the vertebral bone and the question of whether these protrusions and inflammation cause the necrosis, or whether the cartilage migrates into areas that have become necrotic due to other conditions, is under investigation.
They may or may not be symptomatic, and their etiological significance for back pain is controversial.

# Diagnosis
Schmorl's nodes can be detected radiographically, although they can be imaged better by CT or MRI.

# Causes
It is believed that Schmorl's nodes develop following back trauma, although this is incompletely understood.
Other reports indicate someone can be born with Schmorl's nodes.

# Incidence/prevalence
Schmorl's nodes are found in 40 - 75% of autopsies.

# Eponym
Schmorl's nodes are named for German pathologist Christian Georg Schmorl (1861-1932).
Scholl reaction
The Scholl reaction is a coupling reaction between two arene compounds with the aid of a Lewis acid and a protic acid.
The protic acid is often an impurity in the Lewis Acid and also formed in the course of a Scholl reaction. Reagents are iron(III) chloride in dichloromethane, copper(II) chloride, PIFA and boron trifluoride etherate in dichloromethane, Molybdenum(V) chloride and lead tetraacetate with BF3 in acetonitrile .
Given the high reaction temperature and the requirement for strongly acidic catalysts the chemical yield often are low and the method is not a popular one. Intramolecular reactions fair better than the intermolecular ones, for instance in the organic synthesis of 9-phenylfluorene:
Or the formation of the pyrene dibenzo-(a.1)-pyrene from the anthracene] 1-phenylbenz(a)anthracene (66% yield).
One study showed that the reaction lends itself to cascade reactions to form more complex polycyclic aromatic hydrocarbons 
In certain applications such as triphenylene synthesis this reaction is advocated as an alternative for the Suzuki reaction. A reoccurring problem is oligomerization of the product which can be prevented by blocking tert-butyl substituents :
The exact reaction mechanism is not known but could very well proceed through an arenium ion. Just as in electrophilic aromatic substitution, Activating groups such as methoxy improve yield and selectivity :
Segmented sleep
Segmented sleep or divided sleep are modern Western terms for a polyphasic sleep pattern found in medieval and early modern Europe and many modern non-industrial societies, where the night's sleep is evenly divided by a few hours of wakefulness.
The human Circadian rhythm controls a sleep-wake cycle of wakefulness during the day and sleep at night. Superposed on this basic rhythm is a secondary one of light sleep in the early afternoon (see nap and siesta) and quiet wakefulness in the early morning.
The two periods of night sleep were called first sleep (occasionally dead sleep) and second sleep (or morning sleep) in medieval England. First and second sleep are also the terms in the Romance languages, as well as the Tiv of Nigeria: In French, the common term was premier sommeil or premier somme; in Italian, primo sonno or primo sono; in Latin, primo somno or comcubia nocte. There is no common word in English for the period of wakefulness between, apart from paraphrases such as first waking or when one wakes from his first sleep and the generic watch (in its old meaning of being awake). In French an equivalent generic term is dorveille ("twixt sleep and wake").
This period of wakefulness was often only semi-conscious, as the French term implies. It was highly valued in medieval Europe as a time of quiet and relaxation. Peasant couples were often too tired after a long day's work to do much more than eat and go to sleep, but they would wake later on to talk and make love. People would also use this time to pray and reflect, and to interpret dreams, which were more vivid at that hour than upon waking in the morning, and even to visit. This was also a favorite time for authors and poets to write uninterrupted.
There is evidence from sleep research that this period of nighttime wakefulness, combined with a midday nap, result in greater alertness than a single sleep-wake cycle. The brain exhibits high levels of the pituitary hormone prolactin during the period of nighttime wakefulness, which may contribute to the feeling of peace that many people associate with it. It is in many ways similar to the hypnogogic and hypnopompic states which occur just before falling asleep and upon waking, respectively.
Because members of modern industrial societies, with late hours facilitated by electric lighting, no longer have this sleep pattern, they may misinterpret and mistranslate references to it in literature. Common interpretations of the term 'first sleep' are 'beauty sleep' and 'early slumber'. A reference to first sleep in the Odyssey was translated as such in the 17th century, but universally mistranslated in the 20th.
Selective sweep
A selective sweep is the reduction or elimination of variation among the nucleotides in neighbouring DNA of a mutation as the result of recent and strong natural selection.
A selective sweep can occur when a new mutation occurs in a gene that increases the fitness of the carrier relative to other members of the population. Natural selection will favour individuals that have a higher fitness and with time the newly mutated variant of the gene will increase in frequency relative to other variants (alleles) of the gene. As its prevalence increases, the neutral and even slightly deleterious genetic variation linked to the new mutation will also become more prevalent. This phenomenon is called genetic hitchhiking. A strong selective sweep results in a region of the genome where the positively selected haplotype (the mutated allele and its neighbours) are essentially the only ones that exist in the population, resulting in a large reduction of the total genetic variation in that chromosome region.
Whether a selective sweep has occurred or not can be investigated by measuring linkage disequilibrium, i.e., whether a given haplotype is overrepresented in the population. Under neutral evolution, genetic recombination will result in the reshuffling of the different alleles within a haplotype, and no single haplotype will dominate the population. However, during a selective sweep, selection for a positively selected gene variant will also result in selection of neighbouring alleles and less opportunity for recombination. Therefore, the presence of strong linkage disequilibrium might indicate that there has been a 'recent' selective sweep, and can be used to identify sites recently under selection.
A study of genetic variation among 269 humans found evidence for selective sweeps on chromosomes 1, 2, 4, 8, 12, and 22 .
In maize, a recent comparison of yellow and white corn genotypes surrounding Y1 - the phytoene synthetase gene responsible for the yellow endosperm color, shows strong evidence for a selective sweep in yellow germplasm reducing diversity at this locus and linkage disequilibrium in surrounding regions.  White maize lines had increased diversity and no evidence of linkage disequilibrium associated with a selective sweep.
Seminal vesicle
The seminal vesicles are a pair of simple tubular glands posteroinferior to the urinary bladder of males.

# Anatomy
They are approximately 5 cm in length, though the full length of the gland is approximately 10 cm and curled up inside of the structure. Both glands form as an outpocketing of the wall of the ampulla of the vas deferens.
The ducts of the seminal vesicles open into the vas deferens as it enters the prostate gland.

# Function
They secrete a significant proportion of the fluid that ultimately becomes semen.  About 70% of the seminal fluid in humans originates from the seminal vesicles.
The thick secretions contain proteins, enzymes, fructose, mucus, vitamin C, flavins, phosphorylcholine and prostaglandins. The high fructose concentrations provide nutrient energy for the spermatozoa as they travel through the female reproductive system. The fluid is expelled under sympathetic contraction of the muscularis muscle coat.

# Histology
Histologically, the seminal vesicles are defined by their tortuous pathways, false lumens, pseudo-stratified columnar epithelium and cuboidal cells along the basal layer.
The height of these columnar cells, and therefore activity, is dependent upon testosterone levels in the blood.
The lumen is large and stores the fluid secretions between ejaculations.
The mucosa is arranged into convoluted folds, significantly increasing surface area.
Joining the epithelium to the underlying muscularis is a fibroelastic connective tissue layer, with the well-developed muscularis layer composed of an inner circular and outer longitudinal layer of smooth muscle.

# Additional images
- Male reproductive system.
- Coronal section of pelvis, showing arrangement of fasci. Viewed from behind.
- Male pelvic organs seen from right side.
- Fundus of the bladder with the vesicul seminales.
- Vesicul seminales and ampull of ductus deferentes, seen from the front.
- Vertical section of bladder, penis, and urethra.
- Cross section of seminal vesicle through a microscope.
Septic embolism

# Overview
A septic embolism is a type of embolism that is infected with bacteria, resulting in the formation of pus. These may become dangerous if dislodged from their original location. Like other emboli, a septic embolism may be fatal.

# Pathogenesis
Septic emboli most often originate from extrapulmonary locations which have been infected for a time. For example, a person's intravenous access site, which is used to insert intravenous drugs, may become infected. When present in great number, septic emboli can coalesce and mimick a lobar or bronchopnuemonia. The infected site, combined with various coagulants that may be generated by the bacteria or the body, may then break off and enter the circulatory system, potentially causing a clot.

# Identification
A septic embolism can be difficult to identify, as it is often attributed to other disorders or infections of the body. As a result, it may wreak havoc with CT scans. It can also be confused with lymph nodules, considering the similarity in shape and size. However, septic emboli usually lodge in the heart valves, where there are no lymph nodes.
Serum amyloid A
Serum amyloid A (SAA) proteins are a family of apolipoproteins associated with high-density lipoprotein (HDL) in plasma. Different isoforms of SAA are expressed constitutively (constitutive SAAs) at different levels or in response to inflammatory stimuli (acute phase SAAs). These proteins are produced predominantly by the liver.  The conservation of these proteins throughout invertebrates and vertebrates suggests that SAAs play a highly essential role in all animals.

# Acute-phase serum amyloid A proteins
Acute-phase serum amyloid A proteins (A-SAAs) are secreted during the acute phase of inflammation. These proteins have several roles, including the transport of cholesterol to the liver for secretion into the bile, the recruitment of immune cells to inflammatory sites, and the induction of enzymes that degrade extracellular matrix. A-SAAs are implicated in several chronic inflammatory diseases, such as amyloidosis, atherosclerosis, and rheumatoid arthritis.  Three acute-phase SAA isoforms have been reported in mice, called SAA1, SAA2, and SAA3. During inflammation, SAA1 and SAA2 are expressed and induced principally in the liver, whereas SAA3 is induced in many distinct tissues. SAA1 and SAA2 genes are regulated in liver cells by the proinflammatory cytokines IL-1, IL-6, and TNF-. Both SAA1 and SAA2 are induced up to a 1000-fold in mice under acute inflammatory conditions following exposure to bacterial lipopolysaccharide (LPS).  Three A-SAA genes have also been identified in humans, although the third gene, SAA3, is believed to represent a pseudogene that does not generate messenger RNA or protein.  Molecular weights of the human proteins are estimated at 11.7 kDa for SAA1 and 12.8 kDa for SAA4.
Serum amyloid A (SAA) is also an acute phase marker that responds rapidly.  Similar to CRP, levels of acute-phase SAA increase within hours after inflammatory stimulus, and the magnitude of increase may be greater than that of CRP. Relatively trivial inflammatory stimuli can lead to SAA responses. It has been suggested that SAA levels correlate better with disease activity in early inflammatory joint disease than do ESR and CRP. Although largely produced by hepatocytes, more recent studies show that SAA is produced by adipocytes as well, and its serum concentration is associated with body mass index.

# Constitutive serum amyloid A proteins
A fourth SAA (SAA4) was identified in humans and is expressed constitutively in the liver and, thus, is defined as a constitutive SAA (C-SAA).  A similar protein that is now also called SAA4 has since been identified in the mouse; it had originally been designated SAA5.
Sever's disease
Synonyms and keywords: Calcaneal apophysitis; calcaneum osteochondrosis

# Overview
Sever's disease, or calcaneal apophysitis, is the most frequent cause of heel pain in children between the ages of 8 and 13 and is due to an inflammation of growing plates, of the calcaneus in the back of the foot, due to the rapid growth of bone when compared to the calceneal tendon (otherwise known as the Achilles tendon).

# Eponym
It is named for JW Sever, who characterized it in 1912.

# Causes
Severs disease is directly related to overuse of the bone and tendons in the heel. This can come from playing sports (i.e. football, basketball, lacrosse) or anything that involves lots of heel movements. It can be associated with starting a new sport, or the start of a new season. Too much weight bearing down on the heel can also cause it as can excessive traction since the bones and tendons are still developing.

# Prognosis
Severs disease is self-recovering, meaning that it will go away on its own when it is used less or when the bone is through growing. The condition is not expected to create any long-term disability, and expected to subside in 2-8 weeks.
However, while the disease does subside quickly, it can recur, for example at the start of a new sports season, several times if it is not taken care of.

# History and Symptoms
- Complaints of pain or tenderness in the heel (or heels)
- Discomfort upon awaking, or when heel is squeezed
- Limping
- More severe pain after walking and more difficulty walking
- Pain during running or playing sports

# Treatment
Treatment may consist of one or more of the following:
- Stopping sports or other activities that aggravate the condition.
- Elevating the heel
- Stretching hamstring and calf muscles 2-3 times daily
- In some cases, casting may be necessary
- Using R.I.C.E. (Rest, Ice, Compression, Elevation)
- Stretching exercises
- HTP Heel seats
- In some cases medication may be needed (ask doctor)

# Primary Prevention
- Maintain good flexibility through stretching exercises
- Avoid excessive running on hard surfaces
- Use quality, well-fitting shoes with firm support and a shock-absorbent sole

# Related Chapters
- List of childhood diseases
Sex and illness

# Overview
A sex-specific illness is an illness that occurs only in people of one sex. In a more general sense, sex-related illnesses are illnesses that are more common to one sex, or which manifest differently in each sex.
Neither concept should be confused with sexually transmitted diseases, which are diseases that have a significant probability of transmission through sexual contact.
Sex-related illnesses have various causes:
- Sex-linked genetic illnesses
- Parts of the reproductive system that are specific to one sex
- Social causes that relate to the gender role expected of that sex in a particular society.
- Different levels of reporting or diagnosis in each gender.
Examples of sex-related illnesses in humans:
Men:
- Prostate cancer and other diseases of the male reproductive system occur only in men
- Certain genetic diseases, such as colour blindness, occur more frequently in men. They are caused by sex-linked, recessive genes carried on the non-homologous portion of the X chromosome.
- Autism is 4 times more prevalent in males than females.
Women:
- 99% of breast cancer occurs in women
- Ovarian cancer, and other diseases of the female reproductive system occur only in women. endometriosis, another female reproductive disorder occurs almost exclusively in women, but has rarely been found in men undergoing estrogen treatment for prostate cancer.
- More women than men suffer from Sjogren's syndrome, scleroderma, and osteoporosis
- In Western cultures, more women than men suffer from eating disorders such as anorexia nervosa and bulimia
- Women are more likely to suffer from unipolar clinical depression (although bipolar disorder appears to affect both sexes equally)
- Psychologists are more likely to diagnose women than men with borderline or histrionic personality disorder. There is no current agreement on whether this is because of a real underlying difference between the sexes, or simply because of deeply ingrained social attitudes.
- Certain autoimmune diseases may occur predominantly in one sex, for unknown reasons. For example 90% of primary biliary cirrhosis cases are women, whereas primary sclerosing cholangitis is more common in  men.
Sexual maturity

# Overview
Sexual maturity is the age/stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct. In humans, the process of sexually maturing is termed puberty.
Most multicellular organisms are unable to sexually reproduce at birth (or germination), and depending on the species, it may be days, weeks, or years until their bodies are able to do so. Also, certain cues may cause the organism to become sexually mature. They may be external, such as drought, or internal, such as percentage of body fat (such internal cues are not to be confused with hormones which directly produce sexual maturity).
Sexual maturity is brought about by a maturing of the reproductive organs and the production of gametes. It may also be accompanied by a growth spurt or other physical changes which distinguish the immature organism from its adult form. These are termed secondary sex characteristics, and often represent an increase in sexual dimorphism. For example, before puberty, human children have flat chests, but adult females have breasts while adult males do not.
After sexual maturity is achieved, it is possible for some organisms to become infertile, or even to change their sex. Some organisms are hermaphrodites and may or may not be able to produce viable offspring. Also, while in many organisms sexual maturity is strongly linked to age, many other factors are involved, and it is possible for some to display most or all of the characteristics of the adult form without being sexually mature. Conversely, it is also possible for the "immature" form to reproduce (see progenesis).
Shunt (medical)

# Overview
In medicine, a shunt is a hole or passage which moves, or allows movement of, fluid from one part of the body to another. The term may describe either congenital or acquired shunts; and acquired shunts (sometimes referred to as iatrogenic shunts) may be either biological or mechanical.
- Cardiac shunts may be described as right-to-left, left-to-right or bidirectional, or as systemic-to-pulmonary or pulmonary-to-systemic.
- Cerebral shunt: In cases of hydrocephalus, a one-way valve is used to drain excess cerebrospinal fluid from the brain and carry it to other parts of the body. This valve usually sits outside the skull, but beneath the skin, somewhere behind the ear.
- Pulmonary shunts exist when there is normal perfusion to an alveolus, but ventilation fails to supply the perfused region.
- A portosystemic shunt (PSS), also known as a liver shunt, is a bypass of the liver by the body's circulatory system.  It can be either a congenital or acquired condition.
- A portacaval shunt / portal caval shunt is a treatment for high blood pressure in the liver.
Shunt nephritis

# Overview
Shunt nephritis is a rare disease of the kidney that can occur in patients being treated for hydrocephalus with a cerebral shunt. It usually results from an infected shunt that produces a long-standing blood infection, particularly by the bacterium Staphylococcus epidermidis. Kidney disease results from an immune response that deposits immune complexes in the kidney. The most common signs and symptoms of the condition are blood and protein in the urine, anemia, and high blood pressure. Diagnosis is based on these findings in the context of characteristic laboratory values. Treatment includes antibiotics and the prompt removal of the infected shunt. Over half of individuals with shunt nephritis recover completely; most of the remainder have some degree of persistent kidney disease.

# Epidemiology
Shunt nephritis is a rare condition affecting males and females of all ages. It occurs in approximately 0.7-2.3% of patients with shunt infections. Approximately 12% of ventriculoatrial shunts become infected, with Staphylococcus epidermidis being the infectious agent in 75% of cases.

# Pathophysiology
Shunt nephritis occurs when a shunt becomes infected with bacteria, most commonly Staphylococcus epidermidis. Bacteria from this infected shunt seed the bloodstream, leading to blood infection (bacteremia). In response to long-standing infection (months to years), the body mounts an immune response that results in deposition of immune complexes in the kidney, leading to nephritis.

# Clinical manifestations
The clinical presentation of shunt nephritis is variable, but the most common manifestations of shunt nephritis include blood in the urine, protein in the urine, anemia, and high blood pressure. Recurrent fever, enlarged liver and spleen, and a skin rash may also be present. Rarely, the major complaint may be arthritis.
Urinalysis typically demonstrates hematuria and proteinuria. Levels of the complement protein C3 are low, while levels of C-reactive protein and cryoglobulins may be modestly elevated. Blood cultures and cerebrospinal fluid cultures demonstrate Staphylococcus epidermidis, a coagulase-negative species of Staphylococcus. Biopsy of the kidney frequently demonstrates membranoproliferative glomerulonephritis, with deposits of C3, IgM, and IgG.

# Treatment
Management is focused on removing the infectious source. The shunt is removed immediately and antibiotics are begun. The infected shunt, typically a ventriculoatrial shunt, may be replaced with a ventriculoperitoneal shunt.

# Prognosis
In one review, over half of individuals with shunt nephritis made a complete recovery. An additional 40% of individuals had persistent urine abnormalities or end-stage renal disease. Death occurred in 9%.

# History
Shunt nephritis was first described by Black in 1965. Early cases and most cases since then are associated with infections of shunts that connect the ventricular system of the brain to the atria of the heart (ventriculoatrial shunts). Less commonly, shunt nephritis has been reported to arise from infections of shunts connecting the ventricular system to the abdominal cavity (ventriculoperitoneal shunts).