BUN, or blood urea nitrogen, is used predominantly to measure kidney function. BUN reflects the ratio between the production and clearance of urea in the body. Urea is formed almost entirely by the liver from both protein metabolism and protein digestion. The amount of urea excreted as BUN varies with the amount of dietary protein intake.

Increased BUN levels are a sign of kidney dysfunction. An increased BUN level may be due to increased production of urea by the liver or decreased excretion by the kidney. Increased BUN levels are also associated with dehydration and hypochlorhydria.

Decreased BUN levels are associated with malabsorption and a diet low in protein.

The blood brain barrier (BBB) is a physical barrier formed by the arrangement of endothelial cells and tight junctions that line the capillaries which supply blood to the brain. The tissue proteins of the BBB are also present in the enteric nervous system (ENS). The complex ENS network resides in the wall of the gastrointestinal tract, the myenteric plexus and the submucosal plexus.

The ENS controls aspects of gut function, including motility, microvascular circulation, epithelial secretion of fluid, ions and bioactive peptides and intestinal barrier function.

Associated With: Individuals training for professional sports (saliva), Inflammatory bowel disease (saliva), Traumatic brain injury (serum)

BMI Categories:
Underweight = <18.5
Normal weight = 18.5–24.9
Overweight = 25–29.9
Obesity = BMI of 30 or greater

Tracking body weight over time is crucial for maintaining and improving health for several reasons.

Firstly, it allows for the early detection of unhealthy trends, such as rapid weight gain or loss, which can be indicators of underlying health issues like hormonal imbalances, metabolic disorders, or nutritional deficiencies. Regular monitoring helps in maintaining a healthy weight, a key factor in preventing chronic diseases such as diabetes, heart disease, and certain cancers.

Additionally, it enables individuals to assess the effectiveness of their dietary and exercise regimes, guiding necessary adjustments for achieving personal health goals. This tracking also provides motivational feedback, as visible changes in weight can reinforce healthy lifestyle choices.

Furthermore, it aids healthcare professionals in making informed decisions about a patient's health and in customizing treatment plans. In essence, regular weight tracking is a simple yet powerful tool for promoting long-term health and well-being.

Bone isoenzymes, specifically bone-specific alkaline phosphatase (BSAP), are important biomarkers used to assess bone metabolism and turnover. These enzymes play a crucial role in bone formation and mineralization processes.

Bone isoenzymes are a subset of alkaline phosphatases (ALP), which are hydrolytic enzymes that function in an alkaline environment. They are primarily produced by osteoblasts, the cells responsible for bone formation, and are present in the plasma membrane of these cells. The main function of bone isoenzymes is to hydrolyze phosphates, which are then used in the formation of proteins, nucleotides, and the mineralization of bone.

Bordetella pertussis causes whooping cough, a worldwide infectious disease that is transmitted from person to person by droplet infection. Especially children at the age of 0-4 years are affected, and the mortality of infected infants is high.

Boron is normally found in hair but the correlations among Boron absorption, and tissue and hair levels of Boron have yet to be determined. Boron has a low order of toxicity, but excessive intake induces riboflavinuria. Boron is frequently high in hair in association with high levels of potentially toxic elements (i.e. lead, mercury, and cadmium) and exposure to toxic chemicals. Exogenous contamination of hair with B is possible since B is present in some soap. Boron is also present in some cleaners, cements, ceramics and glass.

Borrelia afzelii is a species of Borrelia, a bacterium that can infect various species of vertebrates and invertebrates.

B. afzelii and B. garinii are the primary causes of Lyme disease in Europe and Asia. Coinfection by this Borrelia species with one or more pathogens can occur, carried by the vector, which appears to be in most cases the tick.

Borrelia afzelii is a species of Borrelia, a bacterium that can infect various species of vertebrates and invertebrates. B. afzelii and B. garinii are the primary causes of Lyme disease in Europe and Asia.

Coinfection by this Borrelia species with one or more pathogens can occur, carried by the vector, which appears to be in most cases the tick. In Europe the related genospecies Borrelia afzelii is associated with both EM and acrodermatitis chronica atrophicans (ACA), and several European studies have found compelling evidence for B. afzelii infection in patients with morphea.

Borrelia afzelii is a species of Borrelia, a bacterium that can infect various species of vertebrates and invertebrates. B. afzelii and B. garinii are the primary causes of Lyme disease in Europe and Asia. Coinfection by this Borrelia species with one or more pathogens can occur, carried by the vector, which appears to be in most cases the tick. In Europe the related genospecies Borrelia afzelii is associated with both EM and acrodermatitis chronica atrophicans (ACA), and several European studies have found compelling evidence for B. afzelii infection in patients with morphea.

Borrelia burgdorferi is spirochete class bacterium. B. burgdorferi sensu stricto, B. burgdorferi sensu lato, B. burgdorferi afzelii and B. burgdorferi garinii spirochetes enter the human body through tick bites.

Mixed with tick saliva, Borrelia travels through the circulation and enters different tissues. In some untreated cases, symptoms of pathogenic invasion have involved neurologic, cardiac, or joint disorders. Borrelia pathogenesis can break the blood-brain barrier, which allows invasion of the central nervous system, resulting in neuroborreliosis.

Borrelia burgdorferi sensu lato (B.b.s.l.) with the following subspecies:

- USA: Borrelia burgdorferi sensu stricto (B.b.s.s.), Borrelia andersonii, Borrelia americanum, B. carolinensis, B. bissettii, B. myamotoi

- Europe: Borrelia afzelii, Borrelia garinii, B. spielmanii, B. valaisiana, B. lusitaniae, B. bavariensis

- Asia: Borrelia japonica, B. rutdi, B. tanukii, B. sinica, B. yangtze

Borrelia burgdorferi is spirochete class bacterium. B. burgdorferi sensu stricto, B. burgdorferi sensu lato, B. burgdorferi afzelii and B. burgdorferi garinii spirochetes enter the human body through tick bites.