Allantoin
Urate Oxidase
Ureohydrolases
Tartronates
Glyoxylates
Urea
Racemases and Epimerases
Amidohydrolases
Uric Acid
Membrane Transport Modulators
Amidine-Lyases
Early embryonic lethality in Bmp5;Bmp7 double mutant mice suggests functional redundancy within the 60A subgroup. (1/150)
Members of the BMP family of signaling molecules display a high conservation of structure and function, and multiple BMPs are often coexpressed in a variety of tissues during development. Moreover, distinct BMP ligands are capable of activating common pathways. Here we describe the coexpression of two members of the 60A subfamily of BMPs, Bmp5 and Bmp7, at a number of different sites in the embryo from gastrulation onwards. Previous studies demonstrate that loss of either Bmp5 or Bmp7 has negligible effects on development, suggesting these molecules functionally compensate for each other at early stages of embryonic development. Here we show this is indeed the case. Thus we find that Bmp5;Bmp7 double mutants die at 10.5 dpc and display striking defects primarily affecting the tissues where these factors are coexpressed. The present analysis also uncovers novel roles for BMP signaling during the development of the allantois, heart, branchial arches, somites and forebrain. Bmp5 and Bmp7 do not appear to be involved in establishing pattern in these tissues, but are instead necessary for the proliferation and maintenance of specific cell populations. These findings are discussed with respect to potential mechanisms underlying cooperative signaling by multiple members of the TGF-beta superfamily. (+info)Expression of matrix metalloproteinases during murine chorioallantoic placenta maturation. (2/150)
A large body of experimental evidence supports the participation of two groups of extracellular proteases, matrix metalloproteinases (MMPs), and plasminogen activators/plasmin, in tissue remodeling in physiological and pathological invasion. In the late mouse placenta, several tissue remodeling and cell invasion processes take place. Spongiotrophoblast migration into maternal decidua, as well as decidual extracellular matrix remodeling require the coordinated action of extracellular proteolytic enzymes. Via Northern and in situ hybridization, we have analyzed the spatio-temporal expression patterns of members of the MMP family (stromelysin-3, gelatinases A and B), as well as their inhibitors TIMP-1, -2 and -3 in late murine placenta (days 10.5 to 18.5 of gestation). Gelatinase activity in placental extracts was assessed by substrate zymography. Gelatinase A and stromelysin-3 were found to be prominently expressed in decidual tissue; shortly after midpregnancy, the decidual expression patterns of gelatinase A and stromelysin-3 became overlapping with each other, as well as with the expression domain of TIMP-2. On the other hand, gelatinase B transcripts were expressed only by trophoblast giant cells at day 10.5, and were downregulated at later stages. TIMP-1 and TIMP-3 transcripts were detected in decidual periphery at day 10.5, while later the expression was restricted to the endometrial stroma and spongiotrophoblasts, respectively. The areas of stromelysin-3 expression were the same (giant trophoblasts) or adjacent (decidua) to those where urokinase (uPA) transcripts were detected, suggesting a possible cooperation between these proteinases in placental remodeling. We generated mice doubly deficient for stromelysin-3 and uPA, and report here that these mice are viable and fertile. Furthermore, these animals do not manifest obvious placental abnormalities, thereby suggesting the existence of compensatory/redundant mechanisms involving other proteolytic enzymes. Our findings document the participation of MMPs and their inhibitors in the process of late murine placenta maturation, and warrant the characterization of other members of the MMP family, like membrane type-MMPs, in this process. (+info)Investigation of cell culture media infected with viruses by pyrolysis mass spectrometry: implications for bioaerosol detection. (3/150)
Mass spectrometry coupled with a pyrolysis inlet system was used to investigate media from cell cultures infected with viruses. Cell culture media is an intricate mixture of numerous chemical constituents and cells that collectively produce complicated mass spectra. Cholesterol and free fatty acids were identified and attributed to lipid sources in the media (blood serum supplement and plasma membranes of host cells). These lipid moieties could be utilized as signature markers for rapidly detecting the cell culture media. Viruses are intracellular parasites and are dependent upon host cells in order to exist. Therefore, it is highly probable that significant quantities of media needed to grow and maintain viable host cells would be present if a viral agent were disseminated as an aerosol into the environment. Cholesterol was also detected from a purified virus sample, further substantiating its use as a target compound for detection. Implications of this research for detection of viral bioaerosols, using a field-portable pyrolysis mass spectrometer, is described. (+info)Overlapping positive and negative GATA factor binding sites mediate inducible DAL7 gene expression in Saccharomyces cerevisiae. (4/150)
Allantoin pathway gene expression in Saccharomyces cerevisiae responds to two different environmental stimuli. The expression of these genes is induced in the presence of allantoin or its degradative metabolites and repressed when a good nitrogen source (e. g. asparagine or glutamine) is provided. Three types of cis-acting sites and trans-acting factors are required for allantoin pathway gene transcription as follows: (i) UAS(NTR) element associated with the transcriptional activators Gln3p and Gat1p, (ii) URS(GATA) element associated with the repressor Dal80p, and (iii) UIS(ALL) element associated with the Dal82 and Dal81 proteins required for inducer-dependent transcription. Most of the work leading to the above conclusions has employed inducer-independent allantoin pathway genes (e.g. DAL5 and DAL3). The purpose of this work is to extend our understanding of these elements and their roles to inducible allantoin pathway genes using the DAL7 (encoding malate synthase) as a model. We show that eight distinct cis-acting sites participate in the process as follows: a newly identified GC-rich element, two UAS(NTR), two UIS(ALL), and three URS(GATA) elements. The two GATA-containing UAS(NTR) elements are coincident with two of the three GATA sequences that make up the URS(GATA) elements. The remaining URS(GATA) GATA sequence, however, is not a UAS(NTR) element but appears to function only in repression. The data provide insights into how these cis- and trans-acting factors function together to accomplish the regulated expression of the DAL7 gene that is observed in vivo. (+info)Clostridium innocuum: a glucoseureide-splitting inhabitant of the human intestinal tract. (5/150)
Glycosylureides were recently described as non-invasive markers of intestinal transit time. The underlying principle is an enzymatic splitting of (13)C-labelled ureides by intestinal bacteria. The (13)CO(2) released from the urea moiety of the glycosylureides can be measured in breath samples when the ingested tracer substrate reaches the caecum that is colonised with microbes. To date, the microbes that degrade glycosylureides are unknown. In order to identify the glucoseureide (GU)-splitting bacteria, 174 different strains of intestinal microbes obtained from five healthy adults were checked for their ability to degrade GU. The results of the microbial cultures and thin layer chromatography revealed that GU was exclusively degraded by Clostridium innocuum, belonging to the normal human intestinal microflora. C. innocuum probably synthesises a yet unknown enzyme that splits the glucose-urea bond. We suggest that the term glucoseureidehydrolase is the appropriate designation for this enzyme. (+info)Genetic analysis of a chromosomal region containing genes required for assimilation of allantoin nitrogen and linked glyoxylate metabolism in Escherichia coli. (6/150)
Growth experiments with Escherichia coli have shown that this organism is able to use allantoin as a sole nitrogen source but not as a sole carbon source. Nitrogen assimilation from this compound was possible only under anaerobic conditions, in which all the enzyme activities involved in allantoin metabolism were detected. Of the nine genes encoding proteins required for allantoin degradation, only the one encoding glyoxylate carboligase (gcl), the first enzyme of the pathway leading to glycerate, had been identified and mapped at centisome 12 on the chromosome map. Phenotypic complementation of mutations in the other two genes of the glycerate pathway, encoding tartronic semialdehyde reductase (glxR) and glycerate kinase (glxK), allowed us to clone and map them closely linked to gcl. Complete sequencing of a 15.8-kb fragment encompassing these genes defined a regulon with 12 open reading frames (ORFs). Due to the high similarity of the products of two of these ORFs with yeast allantoinase and yeast allantoate amidohydrolase, a systematic analysis of the gene cluster was undertaken to identify genes involved in allantoin utilization. A BLASTP search predicted four of the genes that we sequenced to encode allantoinase (allB), allantoate amidohydrolase (allC), ureidoglycolate hydrolase (allA), and ureidoglycolate dehydrogenase (allD). The products of these genes were overexpressed and shown to have the predicted corresponding enzyme activities. Transcriptional fusions to lacZ permitted the identification of three functional promoters corresponding to three transcriptional units for the structural genes and another promoter for the regulatory gene allR. Deletion of this regulatory gene led to constitutive expression of the regulon, indicating a negatively acting function. (+info)Systematic review of comparative efficacy and tolerability of calcipotriol in treating chronic plaque psoriasis. (7/150)
OBJECTIVES: To evaluate the comparative efficacy and tolerability of topical calcipotriol in the treatment of mild to moderate chronic plaque psoriasis. DESIGN: Quantitative systematic review of randomised controlled trials. SUBJECTS: 6038 patients with plaque psoriasis reported in 37 trials. MAIN OUTCOME MEASURES: Mean difference in percentage change in scores on psoriasis area and severity index, and response rate ratios for both patients' and investigators' overall assessments of marked improvement or better. Adverse effects were estimated with the rate ratio, rate difference, and number needed to treat. RESULTS: Calcipotriol was at least as effective as potent topical corticosteroids, calcitriol, short contact dithranol, tacalcitol, coal tar, and combined coal tar 5%, allantoin 2%, and hydrocortisone 0.5%. Calcipotriol caused significantly more skin irritation than potent topical corticosteroids (number needed to treat to harm for irritation 10, 95% confidence interval 6 to 34). Calcipotriol monotherapy also caused more irritation than calcipotriol combined with a potent topical corticosteroid (6, 4 to 8). However, the number needed to treat for dithranol to produce lesional or perilesional irritation was 4 (3 to 5). On average, treating 23 patients with short contact dithranol led to one more patient dropping out of treatment owing to adverse effects than if they were treated with calcipotriol. CONCLUSIONS: Calcipotriol is an effective treatment for mild to moderate chronic plaque psoriasis, more so than calcitriol, tacalcitol, coal tar, and short contact dithranol. Only potent topical corticosteroids seem to have comparable efficacy at eight weeks. Although calcipotriol caused more skin irritation than topical corticosteroids this has to be balanced against the potential long term effects of corticosteroids. Skin irritation rarely led to withdrawal of calcipotriol treatment. Longer term comparative trials of calcipotriol versus dithranol and topical corticosteroids are needed to see whether these short term benefits are mirrored by long term outcomes such as duration of remission and improvement in quality of life. (+info)Ureide degradation pathways in intact soybean leaves. (8/150)
Ureides dramatically accumulate in shoots of N(2)-fixing soybean (Glycine max L. Merr.) under water deficit and this accumulation is higher in cultivars that have N(2) fixation that is sensitive to water deficit. One possible explanation is that ureide accumulation is associated with a feedback inhibition of nitrogenase activity. A critical factor involved in ureide accumulation is likely to be the rate of ureide degradation in the leaves. There exists, however, a controversy concerning the pathway of allantoic acid degradation in soybean. Allantoate amidinohydrolase was reported to be the pathway of degradation in studies using the cultivar Maple Arrow and allantoate amidohydrolase was the pathway that existed in the cultivar Williams. This investigation was undertaken to resolve the existence of these two pathways. An in situ technique was developed to examine the response of ureide degradation in leaf tissue to various treatments. In addition, the response of ureide accumulation and N(2) fixation activity was measured for intact plants in response to treatments that differentially influenced the two degradation pathways. The results from these studies confirmed that Maple Arrow and Williams degraded allantoic acid by different pathways as originally reported. The existence of two degradation pathways within the soybean germplasm opens the possibility of modifying ureide degradation to minimize the influence of soil water deficits on N(2) fixation activity. (+info)Allantoin is a naturally occurring substance that is found in some plants and animals, including humans. It is a white, crystalline powder that is only slightly soluble in water and more soluble in alcohol and ether. In the medical field, allantoin is often used as an ingredient in topical creams, ointments, and other products due to its ability to promote wound healing, skin soothing, and softening. It can also help to increase the water content of the extracellular matrix, which can be beneficial for dry or damaged skin. Allantoin has been shown to have anti-inflammatory properties, making it useful in the treatment of various skin conditions such as eczema, dermatitis, and sunburn. It is considered safe and non-irritating, making it a popular ingredient in many cosmetic and personal care products.
Urate oxidase, also known as uricase, is an enzyme that catalyzes the oxidation of uric acid to allantoin. This reaction is an essential part of purine metabolism in many organisms, as allantoin is more soluble and easier to excrete than uric acid. In humans, urate oxidase is non-functional due to mutations in the gene encoding it, which leads to the accumulation of uric acid and predisposes to gout and kidney stones. Urate oxidase is found in some bacteria, fungi, and plants, and can be used as a therapeutic agent in humans to lower serum uric acid levels in conditions such as tumor lysis syndrome and gout.
Hydantoins are a class of chemical compounds that contain a five-membered ring containing two nitrogen atoms, with one of the nitrogens being part of a urea group. They are important in medicine as a specific group of anticonvulsant drugs used to treat seizures, known as hydantoin derivatives or hydantoins proper. The most well-known example is phenytoin (diphenylhydantoin), which has been widely used for this purpose since the 1930s.
The structure of hydantoins allows them to interact with and stabilize voltage-gated sodium channels in the brain, reducing their excitability and thus the likelihood of seizures. However, long-term use of hydantoin derivatives can lead to several side effects, including dizziness, unsteady gait, tremors, and behavioral changes. Regular monitoring of blood levels is necessary to ensure safe and effective treatment with these medications.
Ureohydrolases are a class of enzymes that catalyze the hydrolysis of urea into ammonia and carbon dioxide. The reaction is as follows:
CO(NH2)2 + H2O → 2 NH3 + CO2
The most well-known example of a ureohydrolase is the enzyme urease, which is found in many organisms including bacteria, fungi, and plants. Ureases are important virulence factors for some pathogenic bacteria, as they allow these microorganisms to survive in the acidic environment of the urinary tract by metabolizing urea present in the urine.
Ureohydrolases play a role in various biological processes, such as nitrogen metabolism and pH regulation. However, their activity can also contribute to the formation of kidney stones and other urological disorders if excessive amounts of ammonia are produced in the urinary tract.
Tartronates are salts or esters of tartaric acid, which is a crystalline organic acid found in many fruits and used as an antioxidant and preservative. In the context of medicine, tartronate salts such as potassium tartrate have been used in the treatment of certain metabolic disorders, such as hyperlactacidemia and lactic acidosis, due to their ability to act as a buffering agent and help regulate acid-base balance. However, the use of tartronates in medical therapy is not widely established and has largely been replaced by other more effective treatments.
I'm sorry for any confusion, but "Oxamic Acid" is not a recognized term in medical terminology or pharmacology. It might be a chemical compound that you're interested in, and its scientific definition is as follows:
Oxamic acid, systematically named as ethanedioloic acid or oxalic acid diethyl ester, is an organic compound with the formula (CH3CH2)2C(COOH)2. It is a colorless liquid that is used as a solvent and in the manufacture of other chemicals.
If you're looking for medical information or definitions related to a different term, please let me know and I would be happy to help!
Imidazolines are a class of compounds with a heterocyclic ring containing two nitrogen atoms, one of which is part of an imidazole ring. In the context of medicine and pharmacology, imidazolines are commonly used as decongestants, vasoconstrictors, and as ingredients in some over-the-counter and prescription medications for the treatment of conditions such as allergic rhinitis, nasal congestion, and redness of the eyes.
Imidazoline compounds work by stimulating alpha-adrenergic receptors, which leads to vasoconstriction and decreased blood flow in the affected area. This can help to relieve symptoms such as nasal congestion and red, swollen eyes. However, it is important to note that imidazoline compounds can also have systemic effects when absorbed into the bloodstream, and may cause side effects such as dizziness, dry mouth, and sedation.
Some examples of imidazoline compounds used in medicine include tetrahydrozoline, oxymetazoline, and naphazoline. These compounds are available in various forms, including nasal sprays, eye drops, and oral medications. It is important to follow the instructions for use carefully and to talk to a healthcare provider if you have any questions or concerns about using imidazoline-containing products.
Glyoxylates are organic compounds that are intermediates in various metabolic pathways, including the glyoxylate cycle. The glyoxylate cycle is a modified version of the Krebs cycle (also known as the citric acid cycle) and is found in plants, bacteria, and some fungi.
Glyoxylates are formed from the breakdown of certain amino acids or from the oxidation of one-carbon units. They can be converted into glycine, an important amino acid involved in various metabolic processes. In the glyoxylate cycle, glyoxylates are combined with acetyl-CoA to form malate and succinate, which can then be used to synthesize glucose or other organic compounds.
Abnormal accumulation of glyoxylates in the body can lead to the formation of calcium oxalate crystals, which can cause kidney stones and other health problems. Certain genetic disorders, such as primary hyperoxaluria, can result in overproduction of glyoxylates and increased risk of kidney stone formation.
Urea is not a medical condition but it is a medically relevant substance. Here's the definition:
Urea is a colorless, odorless solid that is the primary nitrogen-containing compound in the urine of mammals. It is a normal metabolic end product that is excreted by the kidneys and is also used as a fertilizer and in various industrial applications. Chemically, urea is a carbamide, consisting of two amino groups (NH2) joined by a carbon atom and having a hydrogen atom and a hydroxyl group (OH) attached to the carbon atom. Urea is produced in the liver as an end product of protein metabolism and is then eliminated from the body by the kidneys through urination. Abnormal levels of urea in the blood, known as uremia, can indicate impaired kidney function or other medical conditions.
Racemases and epimerases are two types of enzymes that are involved in the modification of the stereochemistry of molecules, particularly amino acids and sugars. Here is a brief definition for each:
1. Racemases: These are enzymes that catalyze the interconversion of D- and L-stereoisomers of amino acids or other chiral compounds. They do this by promoting the conversion of one stereoisomer to its mirror image, resulting in a racemic mixture (a 1:1 mixture of two enantiomers). Racemases are important in various biological processes, such as the biosynthesis of some amino acids and the degradation of certain carbohydrates.
Example: Alanine racemase is an enzyme that catalyzes the conversion of L-alanine to D-alanine, which is essential for bacterial cell wall biosynthesis.
2. Epimerases: These are enzymes that convert one stereoisomer (epimer) of a chiral compound into another stereoisomer by changing the configuration at a single asymmetric carbon atom while keeping the rest of the molecule unchanged. Unlike racemases, epimerases do not produce racemic mixtures but rather create specific stereoisomers.
Example: Glucose-1-phosphate epimerase is an enzyme that converts glucose-1-phosphate to galactose-1-phosphate during the Leloir pathway, which is the primary metabolic route for lactose digestion in mammals.
Both racemases and epimerases play crucial roles in various biochemical processes, including the synthesis and degradation of essential molecules like amino acids and carbohydrates.
Amidohydrolases are a class of enzymes that catalyze the hydrolysis of amides and related compounds, resulting in the formation of an acid and an alcohol. This reaction is also known as amide hydrolysis or amide bond cleavage. Amidohydrolases play important roles in various biological processes, including the metabolism of xenobiotics (foreign substances) and endogenous compounds (those naturally produced within an organism).
The term "amidohydrolase" is a broad one that encompasses several specific types of enzymes, such as proteases, esterases, lipases, and nitrilases. These enzymes have different substrate specificities and catalytic mechanisms but share the common ability to hydrolyze amide bonds.
Proteases, for example, are a major group of amidohydrolases that specifically cleave peptide bonds in proteins. They are involved in various physiological processes, such as protein degradation, digestion, and regulation of biological pathways. Esterases and lipases hydrolyze ester bonds in various substrates, including lipids and other organic compounds. Nitrilases convert nitriles into carboxylic acids and ammonia by cleaving the nitrile bond (C≡N) through hydrolysis.
Amidohydrolases are found in various organisms, from bacteria to humans, and have diverse applications in industry, agriculture, and medicine. For instance, they can be used for the production of pharmaceuticals, biofuels, detergents, and other chemicals. Additionally, inhibitors of amidohydrolases can serve as therapeutic agents for treating various diseases, such as cancer, viral infections, and neurodegenerative disorders.
Uric acid is a chemical compound that is formed when the body breaks down purines, which are substances that are found naturally in certain foods such as steak, organ meats and seafood, as well as in our own cells. After purines are broken down, they turn into uric acid and then get excreted from the body in the urine.
However, if there is too much uric acid in the body, it can lead to a condition called hyperuricemia. High levels of uric acid can cause gout, which is a type of arthritis that causes painful swelling and inflammation in the joints, especially in the big toe. Uric acid can also form crystals that can collect in the kidneys and lead to kidney stones.
It's important for individuals with gout or recurrent kidney stones to monitor their uric acid levels and follow a treatment plan prescribed by their healthcare provider, which may include medications to lower uric acid levels and dietary modifications.
Guanine Deaminase is an enzyme that catalyzes the chemical reaction in which guanine, one of the four nucleotides that make up DNA and RNA, is deaminated to form xanthine. This reaction is part of the purine catabolism pathway, which is the breakdown of purines to produce energy and eliminate nitrogenous waste. The gene that encodes this enzyme in humans is located on chromosome 2 and is called GDA. Deficiency in guanine deaminase has been associated with Lesch-Nyhan syndrome, a rare genetic disorder characterized by mental retardation, self-mutilation, spasticity, and uric acid overproduction.
Nitrogen compounds are chemical substances that contain nitrogen, which is a non-metal in group 15 of the periodic table. Nitrogen forms compounds with many other elements due to its ability to form multiple bonds, including covalent bonds with hydrogen, oxygen, carbon, sulfur, and halogens.
Nitrogen can exist in several oxidation states, ranging from -3 to +5, which leads to a wide variety of nitrogen compounds with different properties and uses. Some common examples of nitrogen compounds include:
* Ammonia (NH3), a colorless gas with a pungent odor, used in fertilizers, cleaning products, and refrigeration systems.
* Nitric acid (HNO3), a strong mineral acid used in the production of explosives, dyes, and fertilizers.
* Ammonium nitrate (NH4NO3), a white crystalline solid used as a fertilizer and explosive ingredient.
* Hydrazine (N2H4), a colorless liquid with a strong odor, used as a rocket fuel and reducing agent.
* Nitrous oxide (N2O), a colorless gas used as an anesthetic and laughing gas in dental procedures.
Nitrogen compounds have many important applications in various industries, such as agriculture, pharmaceuticals, chemicals, and energy production. However, some nitrogen compounds can also be harmful or toxic to humans and the environment if not handled properly.
Membrane transport modulators refer to a class of molecules that affect the movement of ions, nutrients, and other substances across cell membranes by interacting with membrane transport proteins. These proteins, also known as transporters or carriers, facilitate the passive or active transport of molecules in and out of cells.
Membrane transport modulators can either inhibit or enhance the activity of these transport proteins. They play a crucial role in pharmacology and therapeutics, as they can influence drug absorption, distribution, metabolism, and excretion (ADME). Examples of membrane transport modulators include ion channel blockers, inhibitors of efflux pumps like P-glycoprotein, and enhancers of nutrient uptake transporters.
It is important to note that the term "membrane transport modulator" can encompass a wide range of molecules with varying mechanisms and specificities, so further characterization is often necessary for a more precise understanding of their effects.
Amidine-lyases are a class of enzymes that catalyze the cleavage of a nitrogen-carbon bond in an amidine molecule, resulting in the formation of a nitrogen gas (N2) and a carbonyl compound. This reaction is also known as deamination or deaminative cleavage.
The systematic name for this class of enzymes is "amidine hydrolase (deaminating)". They are classified under EC number 4.3.1, which includes enzymes that catalyze the hydrolysis of various bonds.
Amidine-lyases play important roles in various metabolic pathways, including the breakdown of amino acids and other nitrogen-containing compounds. They are found in a wide range of organisms, from bacteria to humans.
It's worth noting that amidines are organic compounds containing a nitrogen atom bonded to two carbon atoms, and they can be found in various natural and synthetic compounds. The term "amidine-lyases" refers specifically to enzymes that cleave the nitrogen-carbon bond in these compounds.
Nitrogen is not typically referred to as a medical term, but it is an element that is crucial to medicine and human life.
In a medical context, nitrogen is often mentioned in relation to gas analysis, respiratory therapy, or medical gases. Nitrogen (N) is a colorless, odorless, and nonreactive gas that makes up about 78% of the Earth's atmosphere. It is an essential element for various biological processes, such as the growth and maintenance of organisms, because it is a key component of amino acids, nucleic acids, and other organic compounds.
In some medical applications, nitrogen is used to displace oxygen in a mixture to create a controlled environment with reduced oxygen levels (hypoxic conditions) for therapeutic purposes, such as in certain types of hyperbaric chambers. Additionally, nitrogen gas is sometimes used in cryotherapy, where extremely low temperatures are applied to tissues to reduce pain, swelling, and inflammation.
However, it's important to note that breathing pure nitrogen can be dangerous, as it can lead to unconsciousness and even death due to lack of oxygen (asphyxiation) within minutes.