VERDENIL-10

Indications

• Erectile dysfunction
• Pulmonary arterial hypertension

Dosage

Children: null

Adults: 5 mg once daily, may be adjusted to 2.5 mg once daily or increased to 40 mg once daily if tolerated, depending on indication and response.

Mechanism of action

Vardenafil inhibits cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5), an enzyme responsible for the degradation of cGMP in the corpus cavernosum. During sexual stimulation, nitric oxide (NO) is released which stimulates guanylate cyclase, increasing cGMP levels leading to smooth muscle relaxation and enhanced blood flow into the penis. This process facilitates penile erection.

Pharmacodynamics

Vardenafil is a potent and selective inhibitor of PDE5. By preventing the degradation of cGMP, it promotes smooth muscle relaxation in the corpus cavernosum, increasing blood inflow and supporting erectile function. The drug's effects depend on sexual stimulation; without it, vardenafil does not induce an erection. Potential side effects include prolonged erections, sudden loss of vision, and hearing loss.

Pharmacokinetics

Vardenafil is rapidly absorbed after oral administration, with peak plasma concentrations occurring approximately 1 hour post-dose. The drug has a half-life of about 4 to 5 hours. It is metabolized primarily in the liver by cytochrome P450 enzymes, and both the parent compound and its metabolites are eliminated through urine and feces. Its pharmacokinetics can be affected by food intake and co-administration with other medications.

Contra-indications

• Severe renal impairment
• Concurrent use of nitrates
• Cardiovascular conditions that make sexual activity inadvisable
• Hypotension (systolic blood pressure below 90 mmHg)
• History of priapism or predisposition to priapism (e.g., sickle-cell disease, multiple myeloma, leukemia)

Adverse effects

• Headache
• Flushing
• Dyspepsia
• Nasal congestion
• Visual disturbances
• Sudden loss of vision
• Sudden hearing loss
• Prolonged erection (priapism)

Interactions

• Crizotinib (increases exposure)
• Imatinib (increases exposure)
• Letermovir (increases exposure)
• Nilotinib (increases exposure)
• Antifungal azoles (unknown effect but may increase exposure)

Precautions

• Use with caution in patients with severe heart failure or significant cardiovascular risk
• Monitor for signs of prolonged erection or priapism
• Elderly patients may be at increased risk for adverse effects
• Assess renal and hepatic function before prescribing

Pregnancy

Not indicated for use in women.

Breast-feeding

Not indicated for use in women.

Storage

Store at room temperature, away from moisture and heat.

Formulations

• Tablets: 5 mg, 10 mg

Indications

• Constipation
• Dietary fiber supplementation
• Irritable bowel syndrome
• Diverticular disease
• Weight management

Dosage

Children: Refer to appropriate guidelines for specific dosage; generally taken with adequate fluid intake.

Adults: Refer to appropriate guidelines for specific dosage; generally taken with adequate fluid intake.

Mechanism of action

Cellulose acts primarily as a bulk-forming laxative. It absorbs water in the intestines, which increases stool bulk and stimulates peristalsis, thus facilitating bowel movements. Additionally, cellulose is not digestible by human enzymes, leading to fermentation by gut bacteria, which may enhance gut health and alter gut microbiota composition.

Pharmacodynamics

Cellulose increases stool weight and frequency of bowel movements. It works by retaining water in the intestines, leading to softer stools and improved passage through the gastrointestinal tract. The bulking effect of cellulose can help alleviate constipation and promote overall digestive health. It may also play a role in cholesterol reduction and glycemic control through its effects on digestion and absorption of nutrients.

Pharmacokinetics

Cellulose is not absorbed into the bloodstream due to its indigestible nature. Instead, it passes through the gastrointestinal tract, where it adds bulk to the stool. Its fermentation by colonic bacteria produces short-chain fatty acids, which may have beneficial effects on colon health. The onset of action for cellulose as a laxative can vary but is generally within 24 to 72 hours after ingestion.

Adverse effects

• Bloating
• Flatulence
• Diarrhea
• Abdominal discomfort

Precautions

• Use with caution in patients with a history of gastrointestinal disorders.
• Monitor for potential allergic reactions in sensitive individuals.

Pregnancy

Cellulose is generally considered safe during pregnancy as it is a non-toxic, indigestible fiber.

Breast-feeding

Cellulose is also considered safe during breastfeeding; it is excreted in breast milk in negligible amounts.

Storage

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

Formulations

• Powder
• Capsules
• Tablets
• Granules

Indications

• Hypovolemic shock
• Severe burns
• Postoperative fluid replacement
• Sepsis
• Trauma management

Dosage

Children: Refer to established guidelines for specific dosing, as it varies based on the type of colloidal solution used and the clinical condition being treated.

Adults: Refer to established guidelines for specific dosing, as it varies based on the type of colloidal solution used and the clinical condition being treated.

Mechanism of action

Colloidal solutions work by maintaining oncotic pressure in the blood, thus helping to retain fluid within the vascular system. This is primarily due to the large molecular weight of the colloidal particles, which cannot easily pass through capillary walls. The presence of colloids in the blood helps to draw water into the circulation, increasing blood volume and improving tissue perfusion.

Pharmacodynamics

The pharmacodynamics of colloidal solutions are centered on their ability to exert osmotic pressure, which helps maintain blood volume and pressure. This effect is particularly important in conditions such as hypovolemia and shock, where fluid replacement is necessary to restore hemodynamic stability. The efficacy of colloidal solutions can vary depending on the type of colloid used, as well as the underlying clinical condition being treated.

Pharmacokinetics

Colloidal solutions are typically administered intravenously and their pharmacokinetics can vary based on the specific formulation. Generally, colloids are distributed throughout the vascular compartment and have a longer duration of action compared to crystalloids, as they remain in circulation longer. The elimination of colloids is primarily through the reticuloendothelial system, where they are metabolized or eliminated by the liver and spleen. Factors such as particle size and composition can influence their distribution and clearance.

Adverse effects

• Allergic reactions
• Injection site reactions
• Nausea
• Vomiting
• Headache
• Fever

Precautions

• Use with caution in patients with known allergies to any component of the formulation
• Monitor for signs of hypersensitivity during administration
• Consider volume overload in patients with cardiac or renal impairment

Pregnancy

The safety of colloidal solutions during pregnancy has not been established. Use only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

It is not known whether colloidal solutions are excreted in human milk. Caution should be exercised when administering to breastfeeding mothers.

Storage

Store at room temperature, protect from light, and do not freeze. Keep out of reach of children.

Formulations

• Colloidal silver
• Colloidal gold
• Colloidal iron
• Other metal colloids

Mechanism of action

The precise mechanism of action is not well-documented in the provided resources. However, compounds with similar molecular structures often interact with biological pathways through modulation of neurotransmitter systems or receptor activity.

Pharmacodynamics

Pharmacodynamics for compounds like Colour typically involve interactions at the cellular level, influencing physiological responses through receptor binding and modulation of signaling pathways. The specific effects and potency would depend on the context of use and formulation.

Pharmacokinetics

Information on the pharmacokinetics of Colour, including absorption, distribution, metabolism, and excretion, is not provided in the available resources. Generally, pharmacokinetic properties will vary significantly based on formulation and route of administration.

Pregnancy

Safety in pregnancy has not been established. Use only if the benefits outweigh the risks.

Breast-feeding

Caution is advised. There are no adequate studies in breastfeeding women.

Storage

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

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

• Hypomagnesemia
• Magnesium deficiency
• Cardiac arrhythmias
• Eclampsia
• Asthma exacerbations
• Migraine prophylaxis

Dosage

Children: Refer to the BNF for Children for pediatric dosing recommendations.

Adults: Refer to clinical guidelines or specific product information for adult dosing.

Mechanism of action

Magnesium acts as a cofactor for over 300 enzymatic reactions in the body. It is essential for ATP production, the synthesis of nucleic acids, and the regulation of calcium homeostasis. By modulating calcium channels and neurotransmitter release, magnesium influences neuromuscular transmission and muscle contraction. It also plays a role in stabilizing cellular membranes and protecting against oxidative stress.

Pharmacodynamics

Magnesium's pharmacodynamics involve its effects on various physiological processes, particularly in the cardiovascular and neuromuscular systems. It helps to maintain normal muscle and nerve function and influences cardiac rhythm. Magnesium is known to inhibit excessive calcium influx into cells, thus contributing to vasodilation and lowering blood pressure. It also has a calming effect on the nervous system, which can help alleviate anxiety and promote relaxation.

Pharmacokinetics

Magnesium is absorbed primarily in the small intestine, with the efficiency of absorption being influenced by dietary factors and the presence of other minerals. The body regulates magnesium levels through renal excretion and intestinal absorption. The half-life of magnesium varies depending on the route of administration, with intravenous administration leading to quicker distribution and elimination. The majority of magnesium is stored in the bones, muscles, and soft tissues, with only a small fraction present in the extracellular fluid.

Contra-indications

• Severe renal impairment
• Myasthenia gravis
• Hypocalcemia
• Hypophosphatemia

Adverse effects

• Diarrhea
• Nausea
• Vomiting
• Abdominal cramping
• Hypotension
• Bradypnea
• Muscle weakness

Interactions

• Antibiotics (e.g., tetracyclines, fluoroquinolones) - may bind and reduce their absorption
• Calcium supplements - may compete for absorption
• Diuretics (especially loop diuretics) - can increase the risk of magnesium deficiency
• ACE inhibitors - may enhance the hypotensive effect
• Neuromuscular blocking agents - may potentiate their effects

Precautions

• Use with caution in patients with renal impairment
• Monitor electrolytes in patients with gastrointestinal losses
• Avoid in patients with heart block
• Caution in elderly patients due to potential for electrolyte imbalance

Pregnancy

Magnesium is generally considered safe during pregnancy and is often recommended for certain conditions, such as preeclampsia.

Breast-feeding

Magnesium is excreted in breast milk but is generally considered safe for use during breastfeeding.

Storage

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

Formulations

• Oral tablets
• Oral solution
• Intravenous injection
• Intramuscular injection

Indications

• Used as an excipient in tablet formulations
• Used as a bulking agent in capsule formulations
• Used in food products as a thickener or stabilizer

Dosage

Children: Refer to specific product guidelines as dosage will depend on the formulation and the active ingredients.

Adults: Refer to specific product guidelines as dosage will depend on the formulation and the active ingredients.

Mechanism of action

Microcrystalline cellulose acts as a non-digestible filler that enhances the flow properties of powders during the manufacturing of tablets and capsules. It does not have a direct pharmacological action on the body but ensures that the active ingredients are effectively delivered to the patient.

Pharmacodynamics

As a non-active ingredient, microcrystalline cellulose does not exert pharmacodynamic effects typical of active pharmaceutical ingredients. Its primary role is to provide a stable and consistent matrix for the drug, facilitating the release of the active compound once ingested.

Pharmacokinetics

Microcrystalline cellulose is not absorbed in the gastrointestinal tract; it passes through the digestive system largely unchanged. It adds bulk to the stool, which may aid in promoting regular bowel movements. The substance is excreted in feces, where it contributes to dietary fiber intake.

Pregnancy

Data regarding the use of microcrystalline cellulose during pregnancy is limited. It is advisable to consult with healthcare professionals before use.

Breast-feeding

Microcrystalline cellulose is considered safe during breastfeeding, as it is not absorbed systemically.

Storage

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

Mechanism of action

Oxides do not have a single mechanism of action as they are a broad category of compounds. However, in general, metal oxides can exhibit catalytic properties, while non-metal oxides may participate in biochemical reactions by forming acids or bases upon dissolution in water.

Pharmacodynamics

The pharmacodynamics of oxides depend on the specific type of oxide and its interaction with biological systems. For instance, metal oxides may have antimicrobial properties, while certain non-metal oxides can influence metabolic pathways through their acid-base chemistry. The effects vary widely, necessitating specific studies for each oxide's role in therapeutic contexts.

Pharmacokinetics

The pharmacokinetics of oxides are also variable. Many metal oxides are poorly soluble and thus have limited absorption when ingested. Non-metal oxides, such as carbon dioxide, can be readily absorbed and utilized in metabolic processes. The distribution, metabolism, and excretion of oxides depend on their chemical form and the biological system in which they are involved.

Pregnancy

Not applicable as oxide is not a drug but a class of chemical compounds.

Breast-feeding

Not applicable as oxide is not a drug but a class of chemical compounds.

Storage

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

Indications

• Nutritional support
• Antioxidant supplementation
• Digestive health improvement
• Potential anti-inflammatory effects

Dosage

Children: There is no specific dosage for peaches for pediatric populations. It is recommended to include fruits like peaches in a child's diet as part of a balanced nutritional approach.

Adults: There is no specific dosage for peaches, as they are typically consumed as part of a balanced diet. General recommendations suggest incorporating a variety of fruits, including peaches, into daily dietary intake.

Mechanism of action

The health benefits of peaches are attributed to their high content of bioactive compounds, including phenolic acids, flavonoids, and carotenoids. These compounds exhibit antioxidant properties, which help neutralize free radicals and reduce oxidative stress in the body. Additionally, the dietary fiber in peaches aids in digestive health and contributes to the modulation of blood glucose levels.

Pharmacodynamics

Peaches demonstrate various pharmacodynamic effects due to their rich phytochemical profile. The antioxidants found in peaches can help reduce inflammation and may lower the risk of chronic diseases such as cardiovascular disease and certain types of cancer. The fiber content promotes gut health and can aid in weight management by enhancing satiety.

Pharmacokinetics

The bioactive compounds in peaches are absorbed in the gastrointestinal tract and are metabolized by the liver. Their effects on the body can vary based on individual metabolism, overall diet, and the presence of other compounds. The antioxidants are believed to exert their effects systemically, although specific pharmacokinetic data for peaches as a whole fruit is limited.

Pregnancy

Peaches are generally safe to consume during pregnancy and can provide essential nutrients. However, it is advisable to wash them thoroughly to remove pesticides.

Breast-feeding

Peaches are safe during breastfeeding and can be beneficial due to their nutrient content.

Storage

Store peaches at room temperature until ripe. Once ripe, they can be refrigerated to prolong freshness.

Formulations

• Fresh
• Dried
• Canned
• Juice

Dosage

Children: Refer to specific drug formulations and product labels as purified substances can vary widely in their use and dosing.

Adults: Refer to specific drug formulations and product labels as purified substances can vary widely in their use and dosing.

Mechanism of action

The mechanism of action for purified compounds varies widely depending on the specific substance. Generally, purified drugs exert their effects by interacting with specific biological targets, such as receptors, enzymes, or ion channels, leading to a desired therapeutic effect. This interaction can involve binding to receptors to activate or inhibit signaling pathways, modulating enzymatic activity, or altering physiological processes.

Pharmacodynamics

Pharmacodynamics describes the effects of a drug on the body and the relationship between drug concentration and effect. For purified drugs, this can involve dose-response relationships and the time course of their action. The purified form often enhances potency and reduces variability in response among patients, which can lead to more predictable therapeutic outcomes. The overall effect is determined by the drug's affinity for its target, the efficacy of the drug-receptor interaction, and the downstream signaling pathways activated as a result of this interaction.

Pharmacokinetics

Pharmacokinetics involves the absorption, distribution, metabolism, and excretion (ADME) of a drug. For purified substances, absorption can be more efficient due to the absence of impurities that may affect solubility or stability. Distribution may also be enhanced, leading to higher bioavailability. Metabolism can be influenced by the structure of the purified compound, as it may be metabolized more readily by liver enzymes. Excretion typically occurs through the kidneys or liver, depending on the molecular characteristics of the purified drug.

Pregnancy

Consult with a healthcare professional, as the safety of purified forms of medications during pregnancy may vary depending on the specific substance.

Breast-feeding

Consult with a healthcare professional, as the safety of purified forms of medications during breastfeeding may vary depending on the specific substance.

Storage

Store in a cool, dry place, away from light and moisture, and keep out of reach of children.

Indications

• Silicosis
• Chronic obstructive pulmonary disease (COPD)
• Lung cancer associated with silica exposure

Dosage

Adults: Silica is not administered as a drug, but rather

Mechanism of action

Silica, particularly crystalline forms like quartz and cristobalite, can induce cytotoxicity and morphological transformation in cells. The cytotoxic effects are attributed to the presence of silanol groups and trace iron on the silica surface, which can generate reactive oxygen species. These interactions lead to cellular damage and transformation, suggesting multiple molecular mechanisms underlying silica's biological effects. The activity is sensitive to the silica's surface structure and composition, indicating that the biological response is a phenomenon originating from the silica's surface characteristics.

Pharmacodynamics

Silica's pharmacodynamic effects are largely related to its cytotoxic and transforming properties, particularly in lung tissue. The inhalation of crystalline silica can lead to the activation of inflammatory pathways, oxidative stress, and apoptosis in alveolar macrophages and epithelial cells. This can result in chronic inflammation, fibrosis, and ultimately, diseases such as silicosis and lung cancer. The degree of these effects varies based on the type of silica, its crystalline structure, and the presence of surface modifications.

Pharmacokinetics

The pharmacokinetics of silica is complex as it is not absorbed systemically when inhaled or ingested. Instead, inhaled silica particles can deposit in the alveolar region of the lungs, where they may persist for long periods. The body responds to silica exposure through inflammatory processes, and macrophages attempt to phagocytize silica particles. However, the persistence of these particles can lead to chronic lung conditions. Clearance mechanisms are inefficient, leading to prolonged retention in lung tissue.

Adverse effects

• Cytotoxicity
• Morphological transformation of cells
• Respiratory issues
• Silicosis
• Lung cancer

Precautions

• Use caution in occupational settings with silica dust exposure
• Regular monitoring of lung function in exposed individuals

Pregnancy

There is insufficient data on the effects of silica on pregnancy. It is advised to minimize exposure.

Breast-feeding

Limited data available; caution is advised due to potential respiratory effects.

Storage

Store in a cool, dry place, away from moisture and incompatible materials.

Formulations

• Crystalline silica
• Amorphous silica (diatomaceous earth)
• Silica gel

Mechanism of action

Vardenafil inhibits cyclic guanosine monophosphate (GMP) specific phosphodiesterase type 5 (PDE5), which is responsible for the degradation of cyclic GMP in the corpus cavernosum located around the penis. Penile erection during sexual stimulation is caused by increased penile blood flow resulting from the relaxation of penile arteries and corpus cavernosal smooth muscle. This response is mediated by the release of nitric oxide (NO) from nerve terminals and endothelial cells, which stimulates the synthesis of cyclic GMP in smooth muscle cells. Cyclic GMP causes smooth muscle relaxation and increased blood flow into the corpus cavernosum. The tissue concentration of cyclic GMP is regulated by both the rates of synthesis and degradation via phosphodiesterases (PDEs), and the most abundant PDE in the human corpus cavernosum is PDE5. Therefore, the inhibition of PDE5 by vardenafil enhances erectile function by increasing the amount of cyclic GMP. Penile erection is a hemodynamic process initiated by the relaxation of smooth muscle in corpus cavernosum and its associated arterioles. During sexual stimulation, nitric oxide is released from nerve endings and endothelial cells in the corpus cavernosum. Nitric oxide activates the enzyme guanylate cyclase resulting in increased synthesis of cyclic guanosine monophosphate (cGMP) in the smooth muscle cells of the corpus cavernosum. The cGMP in turn triggers smooth muscle relaxation, allowing increased blood flow into the penis, resulting in erection. The tissue concentration of cGMP is regulated by both the rates of synthesis and degradation via phosphodiesterases (PDEs). The most abundant PDE in the human corpus cavernosum is the cGMP-specific phosphodiesterase type 5 (PDE5); therefore, the inhibition of PDE5 enhances erectile function by increasing the amount of cGMP. Because sexual stimulation is required to initiate the local release of nitric oxide, the inhibition of PDE5 has no effect in the absence of sexual stimulation. In vitro studies have shown that vardenafil is a selective inhibitor of phosphodiesterase type 5 (PDE5). The inhibitory effect of vardenafil is more selective on PDE5 than for other known phosphodiesterases (>15-fold relative to PDE6, >130-fold relative to PDE1, >300-fold relative to PDE11, and >1,000-fold relative to PDE2, 3, 4, 7, 8, 9, and 10).

Pharmacodynamics

Vardenafil is a potent and selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5), an enzyme responsible for the degradation of cGMP in the corpus cavernosum. The presence of cGMP in the corpus cavernosum leads to smooth muscle relaxation, an increased inflow of blood and an erection. Therefore, in patients with erectile dysfunction given vardenafil, normal sexual stimulation will increase cGMP levels in the corpus cavernosum. Without sexual stimulation and no cGMP production, vardenafil should not cause an erection. Vardenafil should not be used in men for whom sexual activity is not recommended due to their underlying cardiovascular status. There is also a risk of developing prolonged erections that last longer than 4 hours, as well as priapism. In the event of a sudden loss of vision in one or both eyes, patients should stop using vardenafil. Patients taking PDE5 inhibitors, such as vardenafil, may also develop sudden hearing loss and experience a prolonged QT interval.

Mechanism of action

...Some quartz and cristobalite dusts (crystalline) as well as the diatomaceous earths (amorphous), but not the pyrogenic amorphous silica, were cytotoxic and induced morphological transformation of SHE cells in a concentration-dependent manner. The ranking in cytotoxicity was different from that in transforming potency, suggesting two separate molecular mechanisms for the two effects. The cytotoxic and transforming potencies were different from one dust to another, even among the same structural silicas. The type of crystalline structure (quartz vs cristobalite) and the crystalline vs biogenic amorphous form did not correlate with cytotoxic or transforming potency of silica dusts. Comparison of cellular effects induced by original and surface modified samples revealed that several surface functionalities modulate cytotoxic and transforming potencies. The cytotoxic effects appeared to be related to the distribution and abundance of silanol groups and to the presence of trace amounts of iron on the silica surface. Silica particles with fractured surfaces and/or iron-active sites, able to generate reactive oxygen species, induced SHE cell transformation. The results show that the activity of silica at the cellular level is sensitive to the composition and structure of surface functionalities and confirm that the biological response to silica is a surface originated phenomenon. In vivo exposure of rat lungs to crystalline silica either by intratracheal instillation or by inhalation results in an increase in mRNA levels for inducible nitric oxide synthase (iNOS) in bronchoalveolar lavage cells (BALC), elevated nitric oxide (.NO) production by BALC, and an increase in .NO-dependent chemiluminescence (CL) from alveolar macrophages (AM). Induction of iNOS message occurs in both AM and polymorphonuclear leukocytes (PMN) harvested from silica-exposed lungs but is not significantly elevated in lavaged lung tissue. This review presents characteristics of simple and complicated coal workers' pneumoconiosis (CWP) as well as pathologic indices of acute and chronic silicosis by summarizing results of in vitro, animal, and human investigations. These results support four basic mechanisms in the etiology of CWP and silicosis: a) direct cytotoxicity of coal dust or silica, resulting in lung cell damage, release of lipases and proteases, and eventual lung scarring; b) activation of oxidant production by pulmonary phagocytes, which overwhelms the antioxidant defenses and leads to lipid peroxidation, protein nitrosation, cell injury, and lung scarring; c) activation of mediator release from alveolar macrophages and epithelial cells, which leads to recruitment of polymorphonuclear leukocytes and macrophages, resulting in the production of proinflammatory cytokines and reactive species and in further lung injury and scarring; d) secretion of growth factors from alveolar macrophages and epithelial cells, stimulating fibroblast proliferation and eventual scarring. Results of in vitro and animal studies provide a basis for proposing these mechanisms for the initiation and progression of pneumoconiosis. Data obtained from exposed workers lend support to these mechanisms. /The authors/ reported previously that freshly fractured silica (FFSi) induces activator protein-1 (AP-1) activation through extracellular signal-regulated protein kinases (ERKs) and p38 kinase pathways. In the present study, the biologic activities of FFSi and aged silica (ASi) were compared by measuring their effects on the AP-1 activation and phosphorylation of ERKs and p38 kinase. The roles of reactive oxygen species (ROS) in this silica-induced AP-1 activation were also investigated. FFSi-induced AP-1 activation was four times higher than that of ASi in JB6 cells. FFSi also caused greater phosphorylation of ERKs and p38 kinase than ASi. FFSi generated more ROS than ASi when incubated with the cells as measured by electron spin resonance (ESR). Studies using ROS-sensitive dyes and