Ammonium Hydroxide
Food Packaging
Food Preservatives
Calcium Hydroxide
Aluminum Hydroxide
Chromatography, Thin Layer
Sodium Hydroxide
Quaternary Ammonium Compounds
Solvents
Magnesium Hydroxide
The photoreduction of H(2)O(2) by Synechococcus sp. PCC 7942 and UTEX 625. (1/32)
It has been claimed that the sole H(2)O(2)-scavenging system in the cyanobacterium Synechococcus sp. PCC 7942 is a cytosolic catalase-peroxidase. We have measured in vivo activity of a light-dependent peroxidase in Synechococcus sp. PCC 7942 and UTEX 625. The addition of small amounts of H(2)O(2) (2.5 microM) to illuminated cells caused photochemical quenching (qP) of chlorophyll fluorescence that was relieved as the H(2)O(2) was consumed. The qP was maximal at about 50 microM H(2)O(2) with a Michaelis constant of about 7 microM. The H(2)O(2)-dependent qP strongly indicates that photoreduction can be involved in H(2)O(2) decomposition. Catalase-peroxidase activity was found to be almost completely inhibited by 10 microM NH(2)OH with no inhibition of the H(2)O(2)-dependent qP, which actually increased, presumably due to the light-dependent reaction now being the only route for H(2)O(2)-decomposition. When (18)O-labeled H(2)O(2) was presented to cells in the light there was an evolution of (16)O(2), indicative of H(2)(16)O oxidation by PS 2 and formation of photoreductant. In the dark (18)O(2) was evolved from added H(2)(18)O(2) as expected for decomposition by the catalase-peroxidase. This evolution was completely blocked by NH(2)OH, whereas the light-dependent evolution of (16)O(2) during H(2)(18)O(2) decomposition was unaffected. (+info)The effects of ammonia on pancreatic enzyme secretion in vivo and in vitro. (2/32)
BACKGROUND: Recent studies clearly demonstrate that Helicobacter pylori (H. pylori) infection of the stomach causes persistent elevation of ammonia (NH3) in gastric juice leading to hypergastrinemia and enhanced pancreatic enzyme secretion. METHODS: The aim of this study is to evaluate the influence of NH4OH on plasma gastrin level and exocrine pancreatic secretion in vivo in conscious dogs equipped with chronic pancreatic fistulas and on secretory activity of in vitro isolated acini obtained from the rat pancreas by collagenase digestion. The effects of NH4OH on amylase release from pancreatic acini were compared with those produced by simple alkalization of these acini with NaOH. RESULTS: NH4OH given intraduodenally (i.d.) in increasing concentrations (0.5, 1.0, 2.0, 4.0, or 8.0 mM/L) resulted in an increase of pancreatic protein output, reaching respectively 9%, 10%, 19%, 16% and 17% of caerulein maximum in these animals and in a marked increase in plasma gastrin level. NH4OH (8 x 0 mM/L, i.d.) given during intravenous (i.v.) infusion of secretin (50 pmol/kg-h) and cholecystokinin (50 pmol/kg-h) reduced the HCO3 and protein outputs by 35% and 37% respectively, as compared to control obtained with infusion of secretin plus cholecystokinin alone. When pancreatic secretion was stimulated by ordinary feeding the same amount of NH4OH administered i.d. decreased the HCO3- and protein responses by 78% and 47% respectively, and had no significant effect on postprandial plasma gastrin. In isolated pancreatic acini, increasing concentrations of NH4OH (10(-7)-10(-4) M) produced a concentration-dependent stimulation of amylase release, reaching about 43% of caerulein-induced maximum. When various concentrations of NH4OH were added to submaximal concentration of caerulein (10(-12) M) or urecholine (10(-5) M), the enzyme secretion was reduced at a dose 10(-5) M of NH4OH by 38% or 40%, respectively. Simple alkalization with NaOH of the incubation medium up to pH 8.5 markedly stimulated basal amylase secretion from isolated pancreatic acini, whereas the secretory response of these acini to pancreatic secretagogues was significantly diminished by about 30%. LDH release into the incubation medium was not significantly changed in all tests indicating that NH4OH did not produce any apparent damage of pancreatic acini and this was confirmed by histological examination of these acini. CONCLUSIONS: 1. NH4OH affects basal and stimulated pancreatic secretion. 2. The excessive release of gastrin may be responsible for the stimulation of basal pancreatic enzyme secretion in conscious animals, and 3. The inhibitory effects of NH4OH on stimulated secretion might be mediated, at least in part, by its direct action on the isolated pancreatic acini possibly due to the alkalization of these acini. (+info)The oxidation state of the photosystem II manganese cluster influences the structure of manganese stabilizing protein. (3/32)
Exposure of photosystem II membranes to trypsin that has been treated to inhibit chymotrypsin activity produces limited hydrolysis of manganese stabilizing protein. Exposure to chymotrypsin under the same conditions yields substantial digestion of the protein. Further probing of the unusual insensitivity of manganese stabilizing protein to trypsin hydrolysis reveals that increasing the temperature from 4 to 25 degrees C will cause some acceleration in the rate of proteolysis. However, addition of low (100 microM) concentrations of NH2OH, that are sufficient to reduce, but not destroy, the photosystem II Mn cluster, causes a change in PS II-bound manganese stabilizing protein that causes it to be rapidly digested by trypsin. Immunoblot analyses with polyclonal antibodies directed against the N-terminus of the protein, or against the entire sequence show that trypsin cleavage produces two distinct peptide fragments estimated to be in the 17-20 kDa range, consistent with proposals that there are 2 mol of the protein/mol photosystem II. The correlation of trypsin sensitivity with Mn redox state(s) in photosystem II suggest that manganese stabilizing protein may interact either directly with Mn, or alternatively, that the polypeptide is bound to another protein of the photosystem II reaction center that is intimately involved in binding and redox activity of Mn. (+info)Efficacy of common laboratory disinfectants on the infectivity of Cryptosporidium parvum oocysts in cell culture. (4/32)
Nine liquid disinfectants were tested for their ability to reduce infectivity of Cryptosporidium parvum oocysts in cell culture. A 4-min exposure to 6% hydrogen peroxide and a 13-min exposure to ammonium hydroxide-amended windshield washer fluid reduced infectivity 1,000-fold. Other disinfectants tested (70% ethanol, 37% methanol, 6% sodium hypochlorite, 70% isopropanol, and three commercial disinfectants) did not reduce the infectivity after a 33-min exposure. The results indicate that hydrogen peroxide and windshield washer fluid or ammonium hydroxide disinfectant may be suitable laboratory disinfectants against C. parvum oocysts. (+info)Structural determination of lipid A of the lipopolysaccharide from Pseudomonas reactans. A pathogen of cultivated mushrooms. (5/32)
The chemical structure of lipid A from the lipopolysaccharide of the mushroom-associated bacterium Pseudomonas reactans, a pathogen of cultivated mushroom, was elucidated by compositional analysis and spectroscopic methods (MALDI-TOF and two-dimensional NMR). The sugar backbone was composed of the beta-(1'-->6)-linked d-glucosamine disaccharide 1-phosphate. The lipid A fraction showed remarkable heterogeneity with respect to the fatty acid and phosphate composition. The major species are hexacylated and pentacylated lipid A, bearing the (R)-3-hydroxydodecanoic acid [C12:0 (3OH)] in amide linkage and a (R)-3-hydroxydecanoic [C10:0 (3OH)] in ester linkage while the secondary fatty acids are present as C12:0 and/or C12:0 (2-OH). A nonstoichiometric phosphate substitution at position C-4' of the distal 2-deoxy-2-amino-glucose was detected. Interestingly, the pentacyl lipid A is lacking a primary fatty acid, namely the C10:0 (3-OH) at position C-3'. The potential biological meaning of this peculiar lipid A is also discussed. (+info)Identification of the extracellular loop 2 as the point of interaction between the N terminus of the chemokine MIP-1alpha and its CCR1 receptor. (6/32)
Macrophage inflammatory peptide-1alpha (MIP-1alpha)/CC-chemokine receptor ligand 3 is an 8-kDa peptide that induces chemotaxis of various lymphocytes to sites of inflammation through interaction with the G protein-coupled chemokine receptors CCR1 and CCR5. We recently described the preparation of a photoactivatable derivative of MIP-1alpha labeled with a benzophenone group at the extreme N-terminal end, which is a determinant for the agonist character of chemokines. Benzophenone-MIP-1alpha is a full agonist that specifically and covalently labels CCR1 and CCR5 receptors upon irradiation. In the present study, we use enzymatic and chemical cleavage methods on wild-type and mutated CCR1 receptors to show that the N terminus of the chemokine MIP-1alpha interacts in a specific manner with the second extracellular loop of the CCR1 receptor, within a segment comprising amino acids 178 to 194. This is the first report on the direct identification of a contact point between the N terminus of a chemokine and its membrane-bound receptor. The work shows that the part of chemokines that is endowed with agonist properties interacts with extracellular parts of the receptor rather than the transmembrane core of the protein. (+info)Ammonium hydroxide hydrolysis: a valuable support in the MALDI-TOF mass spectrometry analysis of Lipid A fatty acid distribution. (7/32)
Lipid A is the lipophilic moiety of lipopolysaccharides (LPSs), the major components of the external membrane of almost all gram-negative bacteria. It is responsible for the toxicity of LPS and has a heterogeneous structure composed of a bis-phosphorylated glucosamine disaccharide backbone that is acylated at the positions 2, 3 of the GlcN I (proximal) and GlcN II (distal) residue with O- and N-linked 3-hydroxy fatty acids (primary substitution). These fatty acids are further acylated by means of their 3-hydroxy groups (secondary substitution). The toxicity of Lipid A is dependent on its primary structure; the number, the length, and the distribution of the fatty acids on the disaccharide backbone strongly influence the endotoxic activity. In this paper a general and easy methodology to obtain secondary fatty acid distribution, which is one of the most difficult issues in the structural determination of Lipid A, is proposed. The method combines ammonium hydroxide hydrolysis and matrix assisted laser desorption ionization (MALDI)-mass spectrometry analysis and has been successfully proven with five different Lipid A species. The procedure exploits the lower stability under mild alkaline conditions of acyl and acyloxyacyl esters with respect to that of the acyl and acyloxyacyl amides. The partially degraded Lipid A species obtained are analyzed by MALDI-MS. The generality of this approach was tested on five Lipid As, namely those arising from Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Pseudomonas reactans, and Burkholderia caryophylli. (+info)Decrease in the efficiency of the electron donation to tyrosine Z of photosystem II in an SQDG-deficient mutant of Chlamydomonas. (8/32)
Photosystem (PS) II activity of a sulfoquinovosyl diacylglycerol (SQDG)-deficient mutant (hf-2) of Chlamydomonas was partially decreased compared with that of wild-type. The susceptibility to 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) was also modified in the mutant. Photometric measurements in the isolated thylakoid membranes of hf-2 revealed that the lowered activity in the mutant was derived from a decrease in the efficiency of the electron donation from water to tyrosine Z, not from the efficiency of the electron transport from Q(A) to Q(B). This result was confirmed by the decay kinetics of chlorophyll fluorescence determined in vivo. We conclude that SQDG contributes to maintaining the conformation of PSII complexes, particularly that of D1 polypeptides, which are necessary for maximum activities in Chlamydomonas. (+info)Ammonium hydroxide is a solution of ammonia (NH3) in water, and it is also known as aqua ammonia or ammonia water. It has the chemical formula NH4OH. This solution is composed of ammonium ions (NH4+) and hydroxide ions (OH-), making it a basic or alkaline substance with a pH level greater than 7.
Ammonium hydroxide is commonly used in various industrial, agricultural, and laboratory applications. It serves as a cleaning agent, a pharmaceutical aid, a laboratory reagent, and a component in fertilizers. In chemistry, it can be used to neutralize acids or act as a base in acid-base reactions.
Handling ammonium hydroxide requires caution due to its caustic nature. It can cause burns and eye damage upon contact, and inhalation of its vapors may lead to respiratory irritation. Proper safety measures, such as wearing protective clothing, gloves, and eyewear, should be taken when handling this substance.
Hydroxides are inorganic compounds that contain the hydroxide ion (OH−). They are formed when a base, which is an electron pair donor, reacts with water. The hydroxide ion consists of one oxygen atom and one hydrogen atom, and it carries a negative charge. Hydroxides are basic in nature due to their ability to donate hydroxide ions in solution, which increases the pH and makes the solution more alkaline. Common examples of hydroxides include sodium hydroxide (NaOH), potassium hydroxide (KOH), and calcium hydroxide (Ca(OH)2). They have various applications in industry, medicine, and research.
I'm sorry for any confusion, but "Food Packaging" is not a medical term. It is a term used to describe the process and materials used to package food products to protect them from contamination, damage, and to provide information about the product. Medical definitions are typically related to diseases, conditions, treatments, or anatomical terms. If you have any questions related to medical terminology, I'd be happy to help with those!
I'm sorry for any confusion, but "Food Technology" is not a term that has a widely recognized medical definition. It is a multidisciplinary field involving aspects of food science, chemical engineering, and nutrition, among others, which deals with the production, preservation, and packaging of food products to make them safe, nutritious, and appealing.
However, if you're asking about how certain food technologies or food components might have medical implications, I could provide some information on that front. For example, there are various food technologies used in the processing and preparation of foods that can affect their nutritional content, safety, and potential health benefits or risks. Some examples include:
* Fortification: adding essential nutrients to foods to prevent deficiencies (e.g., adding folic acid to bread and cereals)
* Pasteurization: heating food to kill harmful bacteria and extend shelf life (e.g., milk, juice, and some prepared foods)
* Irradiation: exposing food to low levels of radiation to reduce or eliminate pathogens and extend shelf life (e.g., spices, herbs, and some fruits and vegetables)
* Food additives: substances added to food for various purposes, such as preservation, coloring, flavoring, or texturizing (e.g., artificial sweeteners, food dyes, and emulsifiers)
Each of these technologies and components can have potential medical implications, both positive and negative, depending on the specific application and individual factors. For example, fortification can help prevent nutrient deficiencies and improve public health, while certain food additives or processing methods may be associated with adverse health effects in some people.
If you have a more specific question about how a particular food technology or component might relate to medical issues, I'd be happy to try to provide more information based on the available evidence!
Food preservatives are substances added to foods to prevent or slow down spoilage caused by microorganisms such as bacteria, yeasts, and molds, or to retard quality deterioration due to oxidation or other chemical reactions. They work by inhibiting the growth of microorganisms, preventing enzymatic reactions that cause spoilage, or scavenging oxygen that can lead to food degradation. Examples of commonly used food preservatives include sodium benzoate, potassium sorbate, sulfites, and nitrites. It is important to note that while food preservatives play a crucial role in maintaining the safety and quality of our food supply, excessive consumption of certain preservatives may have adverse health effects.
Calcium hydroxide is an inorganic compound with the chemical formula Ca(OH)2. It is also known as slaked lime or hydrated lime. Calcium hydroxide is a white, odorless, tasteless, and alkaline powder that dissolves in water to form a caustic solution.
Medically, calcium hydroxide is used as an antacid to neutralize stomach acid and relieve symptoms of heartburn, indigestion, and upset stomach. It is also used as a topical agent to treat skin conditions such as poison ivy rash, sunburn, and minor burns. When applied to the skin, calcium hydroxide helps to reduce inflammation, neutralize irritants, and promote healing.
In dental applications, calcium hydroxide is used as a filling material for root canals and as a paste to treat tooth sensitivity. It has the ability to stimulate the formation of new dentin, which is the hard tissue that makes up the bulk of the tooth.
It's important to note that calcium hydroxide should be used with caution, as it can cause irritation and burns if it comes into contact with the eyes or mucous membranes. It should also be stored in a cool, dry place away from heat and open flames.
Aluminum hydroxide is a medication that contains the active ingredient aluminum hydroxide, which is an inorganic compound. It is commonly used as an antacid to neutralize stomach acid and relieve symptoms of acid reflux and heartburn. Aluminum hydroxide works by reacting with the acid in the stomach to form a physical barrier that prevents the acid from backing up into the esophagus.
In addition to its use as an antacid, aluminum hydroxide is also used as a phosphate binder in patients with kidney disease. It works by binding to phosphate in the gut and preventing it from being absorbed into the bloodstream, which can help to control high phosphate levels in the body.
Aluminum hydroxide is available over-the-counter and by prescription in various forms, including tablets, capsules, and liquid suspensions. It is important to follow the dosage instructions carefully and to talk to a healthcare provider if symptoms persist or worsen.
"Drug storage" refers to the proper handling, maintenance, and preservation of medications in a safe and suitable environment to ensure their effectiveness and safety until they are used. Proper drug storage includes:
1. Protecting drugs from light, heat, and moisture: Exposure to these elements can degrade the quality and potency of medications. Therefore, it is recommended to store most drugs in a cool, dry place, away from direct sunlight.
2. Keeping drugs out of reach of children and pets: Medications should be stored in a secure location, such as a locked cabinet or medicine chest, to prevent accidental ingestion or harm to young children and animals.
3. Following storage instructions on drug labels and packaging: Some medications require specific storage conditions, such as refrigeration or protection from freezing. Always follow the storage instructions provided by the manufacturer or pharmacist.
4. Regularly inspecting drugs for signs of degradation or expiration: Check medications for changes in color, consistency, or odor, and discard any that have expired or show signs of spoilage.
5. Storing drugs separately from one another: Keep different medications separate to prevent cross-contamination, incorrect dosing, or accidental mixing of incompatible substances.
6. Avoiding storage in areas with high humidity or temperature fluctuations: Bathrooms, kitchens, and garages are generally not ideal for storing medications due to their exposure to moisture, heat, and temperature changes.
Proper drug storage is crucial for maintaining the safety, efficacy, and stability of medications. Improper storage can lead to reduced potency, increased risk of adverse effects, or even life-threatening situations. Always consult a healthcare professional or pharmacist for specific storage instructions and recommendations.
Thin-layer chromatography (TLC) is a type of chromatography used to separate, identify, and quantify the components of a mixture. In TLC, the sample is applied as a small spot onto a thin layer of adsorbent material, such as silica gel or alumina, which is coated on a flat, rigid support like a glass plate. The plate is then placed in a developing chamber containing a mobile phase, typically a mixture of solvents.
As the mobile phase moves up the plate by capillary action, it interacts with the stationary phase and the components of the sample. Different components of the mixture travel at different rates due to their varying interactions with the stationary and mobile phases, resulting in distinct spots on the plate. The distance each component travels can be measured and compared to known standards to identify and quantify the components of the mixture.
TLC is a simple, rapid, and cost-effective technique that is widely used in various fields, including forensics, pharmaceuticals, and research laboratories. It allows for the separation and analysis of complex mixtures with high resolution and sensitivity, making it an essential tool in many analytical applications.
Sodium hydroxide, also known as caustic soda or lye, is a highly basic anhydrous metal hydroxide with the chemical formula NaOH. It is a white solid that is available in pellets, flakes, granules, or as a 50% saturated solution. Sodium hydroxide is produced in large quantities, primarily for the manufacture of pulp and paper, alcohols, textiles, soaps, detergents, and drain cleaners. It is used in many chemical reactions to neutralize acids and it is a strong bases that can cause severe burns and eye damage.
Quaternary ammonium compounds (QACs) are a group of disinfectants and antiseptics that contain a nitrogen atom surrounded by four organic groups, resulting in a charged "quat" structure. They are widely used in healthcare settings due to their broad-spectrum activity against bacteria, viruses, fungi, and spores. QACs work by disrupting the cell membrane of microorganisms, leading to their death. Common examples include benzalkonium chloride and cetyltrimethylammonium bromide. It is important to note that some microorganisms have developed resistance to QACs, and they may not be effective against all types of pathogens.
Solvents, in a medical context, are substances that are capable of dissolving or dispersing other materials, often used in the preparation of medications and solutions. They are commonly organic chemicals that can liquefy various substances, making it possible to administer them in different forms, such as oral solutions, topical creams, or injectable drugs.
However, it is essential to recognize that solvents may pose health risks if mishandled or misused, particularly when they contain volatile organic compounds (VOCs). Prolonged exposure to these VOCs can lead to adverse health effects, including respiratory issues, neurological damage, and even cancer. Therefore, it is crucial to handle solvents with care and follow safety guidelines to minimize potential health hazards.
Magnesium hydroxide is an inorganic compound with the chemical formula Mg(OH)2. It is a white solid that is amphoteric, meaning it can react as both an acid and a base. Magnesium hydroxide is commonly used as an over-the-counter antacid to neutralize stomach acid and relieve symptoms of heartburn, acid indigestion, and upset stomach. It works by increasing the pH of the stomach, which can help to reduce the production of stomach acid.
Magnesium hydroxide is also used as a laxative to relieve constipation, as it has a softening effect on stools and stimulates bowel movements. In addition, magnesium hydroxide is sometimes used in medical procedures to neutralize or wash away stomach acid, for example during endoscopies or the treatment of poisoning.
It's important to note that while magnesium hydroxide is generally considered safe when used as directed, it can cause side effects such as diarrhea, nausea, and abdominal cramps. In addition, people with kidney disease or severe heart or lung conditions should use magnesium hydroxide with caution, as it can worsen these conditions in some cases.
High-performance liquid chromatography (HPLC) is a type of chromatography that separates and analyzes compounds based on their interactions with a stationary phase and a mobile phase under high pressure. The mobile phase, which can be a gas or liquid, carries the sample mixture through a column containing the stationary phase.
In HPLC, the mobile phase is a liquid, and it is pumped through the column at high pressures (up to several hundred atmospheres) to achieve faster separation times and better resolution than other types of liquid chromatography. The stationary phase can be a solid or a liquid supported on a solid, and it interacts differently with each component in the sample mixture, causing them to separate as they travel through the column.
HPLC is widely used in analytical chemistry, pharmaceuticals, biotechnology, and other fields to separate, identify, and quantify compounds present in complex mixtures. It can be used to analyze a wide range of substances, including drugs, hormones, vitamins, pigments, flavors, and pollutants. HPLC is also used in the preparation of pure samples for further study or use.