EVERGRAF 0.5

Indications

• Dry eye conditions
• Tear deficiency
• Keratoconjunctivitis sicca

Dosage

Children: Apply as required, typically in the form of eye drops.

Adults: Apply as required, typically in the form of eye drops.

Mechanism of action

Hypromellose acts by forming a viscous gel upon contact with the ocular surface, which helps to retain moisture and protect against irritants. This gel-like property enhances the stability of the tear film and reduces evaporation, thereby alleviating symptoms associated with dry eye conditions.

Pharmacodynamics

The pharmacodynamic effects of hypromellose are primarily related to its ability to mimic natural tears, providing lubrication to the ocular surface. This lubrication reduces friction during blinking and maintains corneal hydration, which is critical for ocular comfort and health. Its high viscosity also contributes to prolonged retention time on the eye surface.

Pharmacokinetics

Hypromellose is administered topically as eye drops and is not significantly absorbed systemically. The retention time of hypromellose on the ocular surface is enhanced due to its viscosity, allowing for extended relief of dry eye symptoms. The elimination of hypromellose occurs primarily through drainage from the eye and dilution by the natural tear fluid.

Adverse effects

• Temporary visual disturbance
• Eye irritation

Precautions

• Should not be used during contact lens wear
• Use with caution in patients with known hypersensitivity to any component of the formulation

Pregnancy

Hypromellose is generally considered safe for use during pregnancy. However, it should be used only if clearly needed and after consulting a healthcare provider.

Breast-feeding

Hypromellose is unlikely to affect breastfed infants when used as directed, but consultation with a healthcare provider is advisable.

Storage

Store in a cool, dry place away from direct sunlight. Once opened, use within a specified period as indicated on the packaging.

Formulations

• {'name': 'Teardew', 'concentration': '0.3%', 'form': 'eye drops', 'volume': '10 ml'}
• {'name': 'Xailin Hydrate', 'concentration': '0.3%', 'form': 'eye drops', 'volume': '10 ml'}
• {'name': 'AacuLose', 'concentration': '0.3%', 'form': 'eye drops', 'volume': '10 ml'}
• {'name': 'Artelac', 'concentration': '0.32%', 'form': 'eye drops', 'volume': '10 ml'}
• {'name': 'Lacrilube', 'concentration': '2 mg/g', 'form': 'eye ointment', 'volume': '3.5 g'}
• {'name': 'Celluvisc', 'concentration': '1%', 'form': 'eye drops', 'volume': '0.4 ml unit dose'}

Indications

• Neuroendocrine tumors of pancreatic origin
• Neuroendocrine tumors of gastrointestinal origin
• Renal cell carcinoma
• Subependymal giant cell astrocytoma associated with tuberous sclerosis complex
• Adjunctive treatment of refractory partial-onset seizures associated with tuberous sclerosis complex

Dosage

Adults: Initially 10 mg once daily, adjusted based on response and tolerability. For renal transplantation, start approximately 4 weeks post-transplantation at an initial dose of 1 mg twice daily.

Mechanism of action

Everolimus binds with high affinity to FK506 binding protein-12 (FKBP-12), forming a complex that inhibits mTOR activation. This inhibition leads to reduced activity of downstream effectors, causing cell cycle arrest in the G1 phase, and ultimately triggering apoptosis. Additionally, everolimus suppresses the expression of hypoxia-inducible factor, decreasing vascular endothelial growth factor levels, which results in reduced cell proliferation and angiogenesis.

Pharmacodynamics

Everolimus exhibits its pharmacological effects by impeding cellular processes involved in growth and metabolism. It effectively reduces the proliferation of cancer cells by inhibiting mTORC1, which is pivotal in protein synthesis and cell growth regulation. Its anti-angiogenic properties stem from the reduction of vascular endothelial growth factor, further curtailing tumor growth and metastasis.

Pharmacokinetics

Everolimus is orally bioavailable, with peak plasma concentrations occurring approximately 1 to 2 hours after administration. It is extensively metabolized by the liver, primarily via CYP3A4, with a half-life of about 30 hours. The drug's pharmacokinetics can be significantly affected by food, hepatic function, and drug interactions, particularly with strong CYP3A4 inhibitors or inducers.

Contra-indications

• Severe liver impairment
• History of bleeding disorders peri-surgical period

Adverse effects

• Alopecia
• Anaemia
• Appetite changes
• Increased risk of infections
• Mouth ulcers
• Nausea
• Fatigue
• Diarrhea

Interactions

• Grapefruit juice increases exposure
• Lumacaftor decreases exposure
• Selpercatinib increases exposure
• Clarithromycin increases exposure
• Dronedarone increases concentration
• Antifungals (azoles) increase concentration
• Belzutifan decreases exposure
• Berotralstat increases concentration
• Cannabidiol increases exposure
• Cenobamate decreases exposure

Precautions

• Monitor liver function regularly
• Adjust dose based on renal function
• Consider monitoring for signs of infection due to immunosuppression

Pregnancy

Limited data on the use of everolimus in pregnancy. Potential risks should be weighed against the benefits. Consult relevant guidelines.

Breast-feeding

Lactation studies are limited. Caution is advised when administering to nursing mothers.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Formulations

• Tablets (Certican®)
• Dispersible tablets (Votubia®)

Mechanism of action

Acetone acts as a solvent and is utilized in various biochemical pathways. It participates in the biosynthesis of isopropanol and is involved in the degradation pathways where it converts into other metabolites such as methylglyoxal and acetoacetate. It also plays a role in pyruvate fermentation and is integral to the fermentation processes in Clostridium acetobutylicum.

Pharmacodynamics

Acetone has a low molecular weight and is highly volatile, which allows it to penetrate biological membranes easily. Its pharmacological effects are primarily due to its role as a solvent and its ability to influence metabolic processes. Acetone can affect lipid metabolism and may impact energy homeostasis by influencing the balance between fat and carbohydrate utilization.

Pharmacokinetics

Acetone is rapidly absorbed through inhalation and dermal exposure. It is distributed throughout the body and can cross the blood-brain barrier. Metabolism occurs primarily in the liver where acetone is converted into acetoacetate and other metabolites. The elimination of acetone occurs mainly through renal excretion, with a half-life varying based on the route of exposure and individual metabolism.

Pregnancy

Acetone is classified as a pregnancy category C drug. Its effects during pregnancy are not well-studied, and caution should be exercised.

Breast-feeding

There is limited information on the excretion of acetone in breast milk. Caution is advised when using acetone during breastfeeding.

Storage

Store in a cool, dry place, away from heat and direct sunlight. Keep tightly closed in original container.

Indications

• Food preservative
• Antioxidant in cosmetics and pharmaceuticals
• Research on oxidative stress

Dosage

Children: Refer to BNF for Children for specific pediatric dosing information.

Adults: Refer to BNF for specific dosing guidelines as it varies based on the formulation and intended use.

Mechanism of action

BHT exhibits a pro-oxidative effect as a phenolic antioxidant, particularly in the presence of initiators like paraquat. It has been shown to chemically donate electrons to paraquat, leading to the generation of reactive oxygen species, which can result in chromosomal damage. This mechanism involves the reduction of paraquat cation to paraquat monocation radical and the subsequent accumulation of oxidative stress in cells.

Pharmacodynamics

As an antioxidant, BHT primarily functions by disrupting lipid peroxidation processes, protecting cellular components from oxidative damage. However, its pro-oxidative actions in combination with certain chemicals may lead to increased oxidative stress and cytotoxicity. The dual role of BHT as both an antioxidant and a pro-oxidant complicates its pharmacodynamic profile, particularly in the context of its interactions with other substances.

Pharmacokinetics

BHT is absorbed in the gastrointestinal tract when ingested, and it is metabolized in the liver. The elimination half-life and metabolic pathways of BHT are not extensively documented, but it is known to undergo biotransformation to various metabolites. The distribution in body tissues can vary based on the dosage and individual metabolism, and it is excreted primarily through urine and feces.

Pregnancy

There are limited data on the use of butylhydroxytoluene (BHT) in pregnancy. It is advised to use caution and consult healthcare professionals before use.

Breast-feeding

Limited information is available regarding the excretion of butylhydroxytoluene in human milk. Caution is recommended when considering use during breastfeeding.

Storage

Store in a cool, dry place away from direct sunlight. Keep container tightly closed.

Formulations

• Food additive
• Cosmetic ingredient

Indications

• Used as an excipient in solid dosage forms
• Facilitates drug disintegration and dissolution

Dosage

Children: Refer to specific product formulation guidelines as crospovidone is used as an excipient and does not have a direct dosage.

Adults: Refer to specific product formulation guidelines as crospovidone is used as an excipient and does not have a direct dosage.

Mechanism of action

Crospovidone acts by rapidly absorbing water and swelling upon contact with moisture. This action leads to the disintegration of solid dosage forms, thus increasing the surface area of the active ingredients and promoting their dissolution and subsequent absorption in the gastrointestinal tract. It does not affect the pH of the formulation, ensuring that the active ingredients remain stable.

Pharmacodynamics

Crospovidone exhibits properties that enhance the bioavailability of active ingredients in pharmaceutical formulations. Its ability to rapidly disintegrate tablets and capsules leads to quicker release and absorption of the drug into systemic circulation. As a disintegrant, it aids in the effective delivery of drugs that may otherwise be poorly soluble.

Pharmacokinetics

Crospovidone itself is not absorbed systemically when administered orally. It remains in the gastrointestinal tract, where it performs its function as a disintegrant. The pharmacokinetic profile of drugs formulated with crospovidone may be influenced by the enhanced dissolution and absorption rates provided by this excipient.

Pregnancy

Crospovidone is considered to have low toxicity and is generally regarded as safe for use during pregnancy, but specific studies are limited.

Breast-feeding

There is insufficient data on the excretion of crospovidone in human milk, but it is deemed safe for use during breastfeeding.

Storage

Store in a cool, dry place away from light and moisture, in tightly closed containers.

Formulations

• Powder
• Tablets

Indications

• Alcohol use disorder
• Acute alcohol intoxication
• Antiseptic for skin disinfection

Mechanism of action

Ethanol affects the brain’s neurons in several ways. It alters their membranes, ion channels, enzymes, and receptors. Ethanol binds directly to the receptors for acetylcholine, serotonin, GABA, and NMDA receptors for glutamate. The sedative effects are mediated through binding to GABA receptors and glycine receptors, while also inhibiting NMDA receptor functioning. As an anti-infective, ethanol acts as an osmolyte, disrupting the osmotic balance across cell membranes. The acute effects result from competitive inhibition of glycine binding to NMDA receptors, leading to disrupted glutamatergic neurotransmission.

Pharmacodynamics

Ethanol produces cellular injury through dehydration and precipitation of cytoplasm, contributing to its bactericidal and antifungal actions. It can lead to neuritis and nerve degeneration when injected near nerve tissues. Up to 98% of ethanol in the body is oxidized, primarily by the hepatic enzyme alcohol dehydrogenase. Its modulation of neurotransmitter receptors, particularly GABA and NMDA, leads to its sedative properties and potential for developing tolerance with chronic use.

Pharmacokinetics

Ethanol is readily absorbed from the gastrointestinal tract and distributed throughout the body. It has a volume of distribution of approximately 0.5 to 0.6 L/kg. Ethanol is metabolized predominantly in the liver by alcohol dehydrogenase to acetaldehyde, which is further oxidized to acetic acid by aldehyde dehydrogenase. The elimination half-life of ethanol varies but is generally around 4 to 5 hours. Factors such as age, sex, body weight, and genetic variability can influence ethanol metabolism.

Contra-indications

• Hypersensitivity to ethanol
• Acute alcohol intoxication
• Severe liver disease
• Pregnancy (in non-medicinal use)
• Severe pancreatitis
• Severe head injury or intracranial bleeding

Adverse effects

• Dizziness
• Nausea
• Vomiting
• Headache
• Sedation
• Cognitive impairment
• Respiratory depression
• Hypotension
• Gastrointestinal bleeding
• Alcohol withdrawal syndrome

Interactions

• CNS depressants (e.g., benzodiazepines, opioids) may enhance sedative effects
• Disulfiram may cause unpleasant reactions when taken with ethanol
• Acetaminophen may increase hepatic toxicity when used with ethanol
• Warfarin may have altered effects when used with ethanol

Precautions

• Caution in patients with a history of alcohol abuse
• Use with caution in patients with hepatic impairment
• Monitor for signs of respiratory depression
• Consider potential for addiction and withdrawal symptoms
• Use in moderation in older adults due to increased sensitivity

Pregnancy

Ethanol should be avoided during pregnancy due to the risk of fetal alcohol spectrum disorders.

Breast-feeding

Ethanol can pass into breast milk; breastfeeding should be avoided for a minimum of 2 hours after consumption.

Storage

Store in a cool, dry place away from light. Keep tightly closed and out of reach of children.

Formulations

• Oral solutions
• Topical antiseptics
• Intravenous formulations
• Medicinal tinctures

Indications

• Lactose intolerance
• As a filler or excipient in pharmaceutical formulations

Dosage

Children: Refer to the BNF for Children for specific dosing information based on age and clinical context.

Adults: Refer to the BNF for specific dosing information based on clinical context.

Mechanism of action

Lactose is metabolized in the intestine by the enzyme lactase into its constituent monosaccharides, glucose and galactose. In individuals with lactase deficiency, unabsorbed lactose passes into the colon, where it is fermented by bacteria, leading to gas production and osmotic effects that contribute to diarrhea.

Pharmacodynamics

The pharmacodynamics of lactose are primarily related to its effects on gastrointestinal function. In healthy individuals, lactose is effectively broken down into glucose and galactose, which are absorbed and utilized for energy. In individuals with lactose intolerance, the unabsorbed lactose can cause osmotic diarrhea and colonic fermentation, leading to discomfort and symptoms associated with lactose intolerance.

Pharmacokinetics

Lactose is not absorbed in the gastrointestinal tract until it is hydrolyzed into glucose and galactose by lactase. The absorption of glucose and galactose occurs in the small intestine. The half-life is not applicable as lactose is not typically administered as a medication but is rather ingested as a natural component of food. Its metabolism primarily occurs in the intestine.

Adverse effects

• Bloating
• Diarrhea
• Abdominal pain
• Flatulence

Precautions

• Use with caution in patients with lactose intolerance.
• Consider potential for gastrointestinal upset in sensitive individuals.

Pregnancy

Lactose is generally considered safe for use during pregnancy. However, consult a healthcare professional for individual advice.

Breast-feeding

Lactose is safe to use while breastfeeding, as it is a natural sugar present in breast milk.

Storage

Store in a cool, dry place, away from direct sunlight.

Formulations

• Powder
• Granules
• Tablets
• Syrup

Indications

• Malignancies
• Lung Fibrosis
• Bronchitis
• Cancer Chemotherapy

Dosage

Children: Refer to the BNF for Children for appropriate dosing guidelines in pediatric patients.

Adults: Refer to the BNF for specific dosage recommendations based on the condition being treated, as it varies by cancer type and patient response.

Mechanism of action

Low-dose exposure to alkylating agents like melphalan induces long-term respiratory complications characterized by bronchitis and lung fibrosis. It stimulates an early release of pro-inflammatory cytokines, such as IL-1beta, IL-6, and IL-23, resulting in neutrophil infiltration in lung tissue within 24 hours. A sustained lymphocytic response follows, lasting at least 14 days, ultimately leading to lung fibrosis, with T lymphocytes, particularly the gamma delta T cell subset, playing a significant role in both the acute and chronic inflammatory responses.

Pharmacodynamics

As an alkylating agent, Lost acts by forming covalent bonds with DNA, resulting in cross-linking that prevents replication and transcription. This mechanism is crucial in its efficacy against rapidly dividing cancer cells, although it also contributes to its toxicity, particularly in normal tissues. The inflammatory response induced can lead to complications, such as lung fibrosis, due to the prolonged recruitment of immune cells.

Pharmacokinetics

The pharmacokinetics of Lost are characterized by its absorption, distribution, metabolism, and excretion, which can vary based on the route of administration. Typically, it is rapidly distributed in tissues, including the lungs. Metabolism occurs primarily via hepatic pathways, leading to active and inactive metabolites. Excretion is mainly renal, and the drug's half-life is influenced by the individual's overall health and organ function.

Pregnancy

There is limited information on the safety of this drug during pregnancy. Use only if the benefits outweigh the risks.

Breast-feeding

Caution is advised as it is not known whether this drug is excreted in human milk.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Dosage

Children: Refer to specific drug formulations and guidelines for dosing.

Adults: Refer to specific drug formulations and guidelines for dosing.

Pregnancy

Consult healthcare providers for risk assessment; data may be limited.

Breast-feeding

Consult healthcare providers as the effects on the infant may vary.

Storage

Store in a cool, dry place away from direct sunlight.

Mechanism of action

Everolimus is a mTOR inhibitor that binds with high affinity to the FK506 binding protein-12 (FKBP-12), thereby forming a drug complex that inhibits the activation of mTOR. This inhibition reduces the activity of effectors downstream, which leads to a blockage in the progression of cells from G1 into S phase, and subsequently inducing cell growth arrest and apoptosis. Everolimus also inhibits the expression of hypoxia-inducible factor, leading to a decrease in the expression of vascular endothelial growth factor. The result of everolimus inhibition of mTOR is a reduction in cell proliferation, angiogenesis, and glucose uptake. Mechanistic target of rapamycin (mTOR) is a serine-threonine kinase that functions via two multiprotein complexes, namely mTORC1 and mTORC2, each characterized by different binding partners that confer separate functions. mTORC1 function is tightly regulated by PI3-K/Akt and is sensitive to rapamycin. mTORC2 is sensitive to growth factors, not nutrients, and is associated with rapamycin-insensitivity. mTORC1 regulates protein synthesis and cell growth through downstream molecules: 4E-BP1 (also called EIF4E-BP1) and S6K. Also, mTORC2 is thought to modulate growth factor signaling by phosphorylating the C-terminal hydrophobic motif of some AGC kinases such as Akt and SGK. Recent evidence has suggested that mTORC2 may play an important role in maintenance of normal as well as cancer cells by virtue of its association with ribosomes, which may be involved in metabolic regulation of the cell. Rapamycin (sirolimus) and its analogs known as rapalogues, such as RAD001 (everolimus) and CCI-779 (temsirolimus), suppress mTOR activity through an allosteric mechanism that acts at a distance from the ATP-catalytic binding site, and are considered incomplete inhibitors. Moreover, these compounds suppress mTORC1-mediated S6K activation, thereby blocking a negative feedback loop, leading to activation of mitogenic pathways promoting cell survival and growth. Consequently, mTOR is a suitable target of therapy in cancer treatments. However, neither of these complexes is fully inhibited by the allosteric inhibitor rapamycin or its analogs. In recent years, new pharmacologic agents have been developed which can inhibit these complexes via ATP-binding mechanism, or dual inhibition of the canonical PI3-K/Akt/mTOR signaling pathway. These compounds include WYE-354, KU-003679, PI-103, Torin1, and Torin2, which can target both complexes or serve as a dual inhibitor for PI3-K/mTOR. This investigation describes the mechanism of action of pharmacological agents that effectively target mTORC1 and mTORC2 resulting in suppression of growth, proliferation, and migration of tumor and cancer stem cells. Mammalian target of rapamycin (mTOR) inhibitors have anti-tumor effects against renal cell carcinoma, pancreatic neuroendocrine cancer and breast cancer. In this study, we analyzed the antitumor effects of mTOR inhibitors in small cell lung cancer (SCLC) cells and sought to clarify the mechanism of resistance to mTOR inhibitors. We analyzed the antitumor effects of three mTOR inhibitors including everolimus in 7 SCLC cell lines by MTS assay. Gene-chip analysis, receptor tyrosine kinases (RTK) array and Western blotting analysis were performed to identify molecules associated with resistance to everolimus. Only SBC5 cells showed sensitivity to everolimus by MTS assay. We established two everolimus resistant-SBC5 cell lines (SBC5 R1 and SBC5 R10) by continuous exposure to increasing concentrations of everolimus stepwise. SPP1 and MYC were overexpressed in both SBC5 R1 and SBC5 R10 by gene-chip analysis. High expression levels of eukaryotic translation initiation factor 4E (eIF4E) were observed in 5 everolimus-resistant SCLC cells and SBC5 R10 cells by Western blotting. MYC siRNA reduced eIF4E phosphorylation in SBC5 cells, suggesting that MYC directly activates eIF4E by an mTOR-independent bypass pathway. Importantly, after reduction of MYC

Mechanism of action

Pro-oxidative effect of phenolic antioxidant (vitamin E) in combination with the initiators on human low-density lipoprotein is known. /It has been/ reported that oxidative stress induced by vitamin E in combination with the herbicide paraquat enhances structural chromosomal damage in cultured anuran leukocytes. In the present study, the phenolic antioxidant vitamin E-synthetic-analogue 2,6-di-tert-butyl-p-cresol (BHT) in combination with paraquat was found to enhance structural chromosomal damage in cultured Pelophylax (Rana) nigromaculatus leukocytes more than paraquat only and paraquat plus nicotinamido adenine dinucleotido phosphate served as positive control, although BHT only had no effect on induction of structural chromosomal damage. Paraquat plus BHT-enhanced structural chromosomal damage was inhibited by combination of the superoxide dismutase mimic Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin and the hydrogen peroxide scavenger catalase. In test based on reduction of paraquat cation, BHT was found to reduce paraquat cation chemically to paraquat monocation radical. These results suggest that BHT functions in chemically donating electron to paraquat and thereby induces an acute accumulation of reactive oxygen species, resulting in increase in chromosomal damage. Promotion of lung tumors in mice by the food additive butylated hydroxytoluene (BHT) is mediated by electrophilic metabolites produced in the target organ. Identifying the proteins alkylated by these quinone methides (QMs) is a necessary step in understanding the underlying mechanisms. Covalent adducts of the antioxidant enzymes peroxiredoxin 6 and Cu,Zn superoxide dismutase were detected previously in lung cytosols from BALB/c mice injected with BHT, and complimentary in vitro studies demonstrated that QM alkylation causes inactivation and enhances oxidative stress. In the present work, adducts of another protective enzyme, carbonyl reductase (CBR), were detected by Western blotting and mass spectrometry in mitochondria from lungs of mice one day after a single injection of BHT and throughout a 28-day period of weekly injections required to achieve tumor promotion. BHT treatment was accompanied by the accumulation of protein carbonyls in lung cytosol from sustained oxidative stress. Studies in vitro demonstrated that CBR activity in lung homogenates was susceptible to concentration- and time-dependent inhibition by QMs. Recombinant CBR underwent irreversible inhibition during QM exposure, and mass spectrometry was utilized to identify alkylation sites at Cys 51, Lys 17, Lys 189, Lys 201, His 28, and His 204. Except for Lys 17, all of these adducts were eliminated as a cause of enzyme inhibition either by chemical modification (cysteine) or site-directed mutagenesis (lysines and histidines). The data demonstrated that Lys 17 is the critical alkylation target, consistent with the role of this basic residue in NADPH binding. These data support the possibility that CBR inhibition occurs in BHT-treated mice, thereby compromising one pathway for inactivating lipid peroxidation products, particularly 4-oxo-2-nonenal. These data, in concert with previous evidence for the inactivation of antioxidant enzymes, provide a molecular basis to explain lung inflammation leading to tumor promotion in this two-stage model for pulmonary carcinogenesis.

Mechanism of action

Ethanol affects the brain’s neurons in several ways. It alters their membranes as well as their ion channels, enzymes, and receptors. Alcohol also binds directly to the receptors for acetylcholine, serotonin, GABA, and the NMDA receptors for glutamate. The sedative effects of ethanol are mediated through binding to GABA receptors and glycine receptors (alpha 1 and alpha 2 subunits). It also inhibits NMDA receptor functioning. In its role as an anti-infective, ethanol acts as an osmolyte or dehydrating agent that disrupts the osmotic balance across cell membranes. ... Ethanol is known to affect a large number of membrane proteins that participate in signaling pathways such as neurotransmitter receptors, enzymes, and ion channels, and there is extensive evidence that ethanol interacts with a variety of neurotransmitters. The major actions of ethanol involve enhancing the inhibitory effects of gamma-aminobutyric acid (GABA) at GABAa receptors and blockade of the N-methyl-D-aspartate (NMDA) subtype of glutamate, an excitatory amine acid (EAA) receptor. Animal studies indicate that the acute effects of ethanol result from competitive inhibition of glycine binding to NMDA receptor and disruption of glutamatergic neurotransmission by inhibiting the response of the NMDA receptor. Persistent glycine antagonism and attenuation of glutamatergic neurotransmission by chronic ethanol exposure results in tolerance to ethanol by enhancing EAA neurotransmission and NMDA receptor upregulation. The latter appears to involve selective increases in NMDA R2B subunit concentrations and other molecular changes in specific brain loci. The abrupt withdrawal of ethanol thus produces a hyperexcitable state that leads to the ethanol withdrawal syndrome and excitotoxic neuronal death. GABA-mediated inhibition, which normally acts to limit excitation, is eliminated during ethanol withdrawal syndrome and further intensifies this excitation. In addition, NMDA receptors function to inhibit the release of dopamine in the nucleus accumbens and mesolimbic structures, which modulate the reinforcing action of addictive xenobiotics such as ethanol. By inhibiting NMDA receptor activity, ethanol could increase dopamine release from the nucleus accumbens and ventral tegmental area and could thus create dependence. Chronic ethanol administration also results in tolerance, dependence, and an ethanol withdrawal syndrome, mediated, in part, by desensitization and or downregulation of GABAa receptors. The development of alcoholic ketoacidosis (AKA) requires that a combination of physical and physiologic events occur. The normal response to starvation and depletion of hepatic glycogen stores is for amino acids to be converted to pyruvate. Pyruvate can serve as a substrate for gluconeogenesis, be converted to acetyl-CoA, which can enter the Krebs cycle or can be utilized in various biosynthetic pathways (eg, fatty acid, ketone bodies, cholesterol, and acetylcholine) ... Ethanol metabolism generates NADH, resulting in an excess of reducing potential. This high redox state favors the conversion of pyruvate to lactate, diverting pyruvate from being a substrate for gluconeogenesis. To compensate for the lack of normal metabolic substrates, the body mobilizes fat from adipose tissue and increased fatty acid metabolism as an alternative source of energy. This response is mediated by a decrease in insulin and an increased secretion of glucagon, catecholamines, growth hormone, and cortisol. Fatty acid metabolism results in the formation of acetyl-CoA and it combines with the excess acetate that is generated from ethanol metabolism to form acetoacetate. Most of the acetoacetate is reduced to beta-hydroxybutyrate due to the excess reducing potential or high redox state of the cell. Volume depletion interferes with the renal elimination of acetoacetate and beta-hydroxybutyrate, and contributes to the acidosis. An elevated lactate concentration may result from shunting from pyruvate or

Pharmacodynamics

Alcohol produces injury to cells by dehydration and precipitation of the cytoplasm or protoplasm. This accounts for its bacteriocidal and antifungal action. When alcohol is injected in close proximity to nerve tissues, it produces neuritis and nerve degeneration (neurolysis). Ninety to 98% of ethanol that enters the body is completely oxidized. Ethanol is also used as a cosolvent to dissolve many insoluble drugs and to serve as a mild sedative in some medicinal formulations. Ethanol also binds to GABA, glycine, NMDA receptors and modulates their effects. Ethanol is also metabolised by the hepatic enzyme alcohol dehydrogenase.

Mechanism of action

Low-dose exposure of alkylating mustard gas causes long-term respiratory complications characterized by bronchitis and lung fibrosis. In this study, we utilized a mouse model for lung exposure of the nitrogen mustard melphalan, in order to define early and late events in the pathogenesis such as expression of pro-inflammatory cytokines, recruitment of inflammatory cells to airways and late-phase fibrosis. /The authors/ investigated the roles of different T lymphocyte subsets on the inflammatory response by using knockout mice lacking either the genes expressing T cell receptor (TCR)-alpha beta or TCR-gamma delta, and compared the responsiveness with that of wild type mice and double knockout mice completely deficient in T cells. Exposure to melphalan induced an early burst of the pro-inflammatory cytokines interleukin (IL)-1beta, IL-6 and IL-23 in airways, followed by extensive infiltration of neutrophils in the lung tissue and airways within 24hr. The acute phase was followed by a sustained lymphocytic response that persisted for at least 14 days with resulting lung fibrosis. Engagement of T lymphocytes, particularly the gamma delta T cell subset, was crucial both for the acute cytokine and neutrophil response and for the late-phase lung fibrosis as indicated by the lack of response in gamma delta T cell deficient mice. /The/ data demonstrate that T lymphocytes play a prominent role in the pathogenesis of long-term lung injuries caused by strong alkylating agents. Sulphur mustard (SM) is a chemical warfare agent that causes erythema and blistering of the skin with a latency of several hours. Although SM is known for almost 200 years the cellular mechanisms involved in the damaging process are not fully understood. There is evidence that changes in nitric oxide (*NO), reactive oxygen species (ROS) and reactive nitrogen species (RNS) might be involved in the damaging process.To find out more about the pathophysiology of SM, /the authors/ investigated the initial formation of biochemical markers of nitrosative and oxidative stress as well as activation (translocation from plasma-membrane) and upregulation of eNOS and iNOS, respectively. Human immortalized keratinocytes (HaCaT cell line) were exposed to SM (100 uM or 300 uM) for 30 min. Cells were fixed after 1hr, 3hr or 6hr of incubation in SM-free medium and immunostained. Live cell experiments were performed using the NO-sensitive dye DAF2-DA. In order to assess cell viability after BH(4) supplementation, /investigators/ analyzed apoptosis using CDD-ELISA. SM significantly increased biochemical markers of nitrosative and oxidative stress already 1hr after exposure. Moreover, the NO producing enzymes eNOS and iNOS showed concentration- and time-dependent changes in their activation or expression levels. Initially, live cell imaging experiments could not confirm NO production after SM exposure. Only when cells were supplemented with tetrahydrobiopterine, stable NO production was detectable. Apoptotic activity was increased due to SM exposure and could be reduced after BH(4) treatment. Our data point towards concentration- and time-dependent formation of iNOS and activation of eNOS due to translocation from plasma-membrane. Live cell experiments yielded first indications of catalytic decoupling of NOS that could be reversed by supplementation with tetrahydrobiopterin (BH(4)). Addition of BH(4) 1hr after SM exposure significantly decreased apoptosis compared to the unsupplemented control. The biochemical sequelae to chloroethyl mustard exposure correspond very well to toxic processes initiated by free radicals. Additionally, mustard solutions contain spontaneously formed cyclic onium ions which produce carbon free radicals when reduced electrochemically. Therefore, /the authors/ hypothesized that the onium ions of sulfur or nitrogen mustards might produce carbon free radicals upon being reduced enzymatically, and that these radicals might constitute a metabolic activation. /The au