Polyvinyl Alcohol
Polyvinyl Chloride
Polyvinyls
Alcohol Drinking
Surgical Sponges
Gelatin Sponge, Absorbable
Embolization, Therapeutic
Phenylmercury Compounds
Enbucrilate
Ethiodized Oil
Alcohols
Fixatives
Chemoembolization, Therapeutic
Ophthalmic Solutions
Preservatives, Pharmaceutical
A retrospective cohort study of male workers exposed to PVA fibers. (1/220)
In order to ascertain whether PVA fibers can produce cancer in humans or not, we have conducted a retrospective cohort study of workers exposed to PVA fibers. A total of 447 exposed and 2416 non-exposed male workers who were engaged before 1980 were followed up until the end of 1996. The SMR for all causes was 0.57 (observed 38, 95% CI: 0.41-0.78) for the exposed, and 0.66 (observed 210, 95% CI: 0.58-0.75). As for lung cancer, its SMR was 0.77 (observed 3, 95% CI: 0.15-2.24) for the exposed workers and 0.67 (12 observed, 95% CI: 0.34-1.16) for the non-exposed workers. Lung cancer SMR was 0.86 (observed 2, 95% CI: 0.10-3.11) for the workers with 20 or more years' employment. This study showed no difference in lung cancer risk between the workers exposed to PVA fibers and the non-exposed workers. (+info)Enhanced degradation of polyvinyl alcohol by Pycnoporus cinnabarinus after pretreatment with Fenton's reagent. (2/220)
Degradation of polyvinyl alcohol (PVA) was investigated by using a combination of chemical treatment with Fenton's reagent and biological degradation with the white rot fungus Pycnoporus cinnabarinus. Inclusion of the chemical pretreatment resulted in greater degradation of PVA than the degradation observed when biological degradation alone was used. (+info)Hypervascular spinal tumors: influence of the embolization technique on perioperative hemorrhage. (3/220)
BACKGROUND AND PURPOSE: Corporectomy is an effective treatment for vertebral metastases; however, massive perioperative hemorrhage is often associated with this procedure. We compared preoperative particle, particle-coil, and coil embolizations of hypervascular spinal tumors prior to vertebral body replacement to determine which prevented perioperative hemorrhage most effectively. METHODS: The vertebral tumors of 59 patients were embolized prior to corporectomy. In 26 cases, only coils were used for the proximal occlusion of feeding segmental arteries. Twenty-four patients received a combination of polyvinyl alcohol (PVA) particles and coils, and nine tumors were embolized with particles alone. We compared intraoperative blood loss between the three groups and 10 other patients who did not undergo embolization prior to corporectomy. RESULTS: Estimation of intraoperative hemorrhage showed a median value of 4350 mL in patients without embolization, 2650 mL in cases of coil embolization, 1850 mL in cases of particle-coil embolization, and 1800 mL in cases of particle embolization. The difference between unembolized patients and those who underwent coil embolization was not statistically significant. Particle and particle-coil embolizations showed very similar results, and reduced hemorrhage significantly as compared to unembolized and proximal coil occlusion cases. Residual bleeding came from the venous system and the neighborhood of the embolized region. CONCLUSION: Particle embolization prior to corporectomy can reduce perioperative hemorrhage. The additional benefit of proximal coil occlusion of arterial feeders is questionable. (+info)Water-soluble aluminium phthalocyanine-polymer conjugates for PDT: photodynamic activities and pharmacokinetics in tumour-bearing mice. (4/220)
The potential use of unsubstituted aluminium phthalocyanine (AlClPc) as a sensitizer for photodynamic therapy (PDT) of cancer has not been fully exploited in spite of its higher efficiency as compared to the sulphonated derivatives. This is largely due to the strong hydrophobic character of AlClPc which renders the material difficult to formulate for in vivo administration. We prepared two water-soluble derivatives of AlClPc by axial coordination of polyethyleneglycol (PEG, MW 2000) or polyvinylalcohol (PVA, MW 13,000-23,000) to the central aluminium ion. Their photodynamic activities were evaluated in vitro against the EMT-6 mouse mammary tumour cells and in vivo against the EMT-6 and the colon carcinoma Colo-26 tumours implanted intradermally in Balb/c mice. Pharmacokinetics were studied in the EMT-6 tumour-bearing mice. After 1 h incubation, the light dose required to kill 90% of cells (LD90) was at least three times less for AlClPc (Cremophor emulsion) as compared to AlPc-PEG and AlPc-PVA, while after 24 h incubation all three preparations were highly phototoxic. All three dye preparations induced complete EMT-6 tumour regression in 75-100% of animals at a low drug dose (0.25 micromol kg(-1)) following PDT (400 J cm(-2), 650-700 nm) at 24 h pi. Complete tumour regression in the Colo-26 tumour model was obtained in 30% of mice at a dose of 2 micromol kg(-1). In the non-cured animals, AlPc-PVA induced the most significant tumour growth delay. This dye showed a prolonged plasma half-life (6.8 h) as compared to AlClPc (2.6 h) and AlPc-PEG (23 min), lower retention by liver and spleen and higher tumour-to-skin and tumour-to-muscle ratios. Our data demonstrate that addition of hydrophilic axial ligands to AlPc, while modifying in vitro and in vivo kinetics, does not reduce the PDT efficiency of the parent molecule. Moreover, in the case of the polyvinylalcohol derivative, axial coordination confers advantageous pharmacokinetics to AlPc, which makes this photosensitizer a valuable, water soluble candidate drug for clinical PDT of cancer. (+info)Comparative hazards of chrysotile asbestos and its substitutes: A European perspective. (5/220)
Although the use of amphibole asbestos (crocidolite and amosite) has been banned in most European countries because of its known effects on the lung and pleura, chrysotile asbestos remains in use in a number of widely used products, notably asbestos cement and friction linings in vehicle brakes and clutches. A ban on chrysotile throughout the European Union for these remaining applications is currently under consideration, but this requires confidence in the safety of substitute materials. The main substitutes for the residual uses of chrysotile are p-aramid, polyvinyl alcohol (PVA), and cellulose fibers, and it is these materials that are evaluated here. Because it critically affects both exposure concentrations and deposition in the lung, diameter is a key determinant of the intrinsic hazard of a fiber; the propensity of a material to release fibers into the air is also important. It is generally accepted that to be pathogenic to the lung or pleura, fibers must be long, thin, and durable; fiber chemistry may also be significant. These basic principles are used in a pragmatic way to form a judgement on the relative safety of the substitute materials, taking into account what is known about their hazardous properties and also the potential for uncontrolled exposures during a lifetime of use (including disposal). We conclude that chrysotile asbestos is intrinsically more hazardous than p-aramid, PVA, or cellulose fibers and that its continued use in asbestos-cement products and friction materials is not justifiable in the face of available technically adequate substitutes. (+info)Embolization of cerebral arteriovenous malformations achieved with polyvinyl alcohol particles: angiographic reappearance and complications. (6/220)
BACKGROUND AND PURPOSE: The appropriate choice of embolic materials with respect to the permanency of obliterated nidi after embolization and complications related to the procedure is essential for safe and effective embolization of cerebral arteriovenous malformations (AVMs). Our purpose was to ascertain the recanalization and complication rates after AVM treatment with polyvinyl alcohol (PVA) particles. METHODS: Between 1988 and 1994, 36 AVMs were embolized with PVA particles at our institution. Follow-up angiographic findings and occurrence of complications during the embolization procedures were analyzed retrospectively. RESULTS: Complete obliteration of the nidus immediately after embolization was achieved in five patients, and 80% to 99% obliteration was attained in 12 patients. Fifty-one follow-up angiographic examinations were performed 1 week to 60 months (mean, 7 months) after embolization in 31 patients. An increase in nidal size was seen on 15 follow-up angiograms (29%) and a decrease was seen in seven (14%). In 28 of the 51 angiograms obtained more than 1 month after follow up (mean, 13 months), 12 (43%) showed AVM enlargement. In four (80%) of five cases of complete obliteration, nidi reappeared on follow-up angiograms. Hemorrhagic complications occurred in three cases and ischemic ones in seven. One patient (3%) died and five (14%) suffered persistent neurologic deficits. CONCLUSION: Embolization with PVA particles can produce significant volume reduction in AVM nidal size, but recanalization is a distinct possibility. (+info)Targeted delivery of anti-angiogenic agent TNP-470 using water-soluble polymer in the treatment of choroidal neovascularization. (7/220)
PURPOSE: The conjugation of drugs with water-soluble polymers such as poly(vinyl alcohol) (PVA) tends to prolong the half-life of drugs and facilitate the accumulation of drugs in tissues involving neovascularization. The purpose of this study was to evaluate the effect of TNP-470-PVA conjugate on the proliferation of endothelial cells in vitro and on experimental choroidal neovascularization (CNV) in vivo. METHODS: TNP-470 was conjugated in PVA by a dimethylaminopyridine-catalyzed reaction. The effects of TNP-470-PVA and free TNP-470 on the proliferation of human umbilical vein endothelial cells (HUVECs) and bovine retinal pigment epithelial cells (BRPECs) were evaluated by the tetrazolium-based colorimetric assay (XTT assay). Experimental CNV was induced by subretinal injection of gelatin microspheres containing basic fibroblast growth factor, into rabbits. Thirty rabbits were intravenously treated either with TNP-470-PVA (n = 8), free TNP470 (n = 5), free PVA (n = 5), or saline (n = 12) daily for 3 days, 2 weeks after implantation of gelatin microspheres. Fluorescein angiography was performed to detect the area with CNV, and the evaluation was made by computerized measurement of digital images. These eyes were also examined histologically. To observe the accumulation of conjugate, 3 rabbits with CNV received rhodamine B isothiocyanate-binding PVA (RITC-PVA), and the lesion was studied 24 hours later by fluorescein microscopy. RESULTS: The TNP-470-PVA inhibited the growth of HUVECs, similar to that of free TNP-470. The BRPECs were less sensitive to TNP-470-PVA than were the HUVECs. TNP-470-PVA significantly inhibited the progression of CNV in rabbits (P = 0.001). Histologic studies at 4 weeks after treatment demonstrated that the degree of vascular formation and the number of vascular endothelial cells in the subretinal membrane of the eyes treated with TNP-470-PVA were less than those of the control eyes. RITC-PVA remained in the area with CNV 24 hours after administration. CONCLUSIONS: These results suggest that TNP-470-PVA inhibited the proliferation of HUVECs more sensitively than that of BRPECs, and the targeted delivery of TNP-470-PVA may have potential as a treatment modality for CNV. (+info)Evaluation of Streck tissue fixative, a nonformalin fixative for preservation of stool samples and subsequent parasitologic examination. (8/220)
We undertook a study to evaluate Streck tissue fixative (STF) as a substitute for formalin and polyvinyl alcohol (PVA) in fecal preservation. A comparison of formalin, PVA, (mercuric chloride based), and STF was done by aliquoting fecal samples into each fixative. Stool specimens were collected in Haiti, and parasites included Cyclospora cayetanensis, Giardia intestinalis, Entamoeba coli, Iodamoeba butschlii, Endolimax nana, Ascaris lumbricoides, Trichuris trichiura, Strongyloides stercoralis, and Necator americanus. Preserved stools were examined at various predetermined times (1 week, 1 month, and 3 months) to establish the quality of the initial preservation as well as the suitability of the fixative for long-term storage. At each time point, stool samples in fixatives were examined microscopically as follows: (i) in wet mounts (with bright-field and epifluorescence microscopy), (ii) in modified acid-fast-, trichrome-, and safranin-stained smears, and (iii) with two commercial test kits. At the time points examined, morphologic features remained comparable for samples fixed with 10% formalin and STF. For comparisons of STF- and 10% formalin-fixed samples, specific findings showed that Cyclospora oocysts retained full fluorescence, modified acid-fast- and safranin-stained smears of Cryptosporidium and Cyclospora oocysts were equal in staining quality, and results were comparable in the immunofluorescence assay and enzyme immunoassay commercial kits. Stool fixed in STF and stained with trichrome showed less-than-acceptable staining quality compared with stool fixed in PVA. STF provides an excellent substitute for formalin as a fixative in routine examination of stool samples for parasites. However, modifications to the trichrome staining procedures will be necessary to improve the staining quality for protozoal cysts fixed in STF to a level comparable to that with PVA. (+info)I'm sorry for any confusion, but "Polyvinyl Alcohol" is not a medical term. It is a chemical compound used in various industrial and commercial applications, including the production of adhesives, paints, and medical devices. Polyvinyl Alcohol is a type of synthetic polymer made from the polymerization of vinyl acetate monomer, followed by alcoholysis to replace the acetate groups with hydroxyl groups.
In a medical context, Polyvinyl Alcohol might be used in certain medical devices or applications, such as contact lenses, eye drops, and drug delivery systems, due to its biocompatibility and resistance to protein absorption. However, it is not a term commonly used to describe a medical condition or treatment.
I'm sorry for any confusion, but "Polyvinyl Chloride" (PVC) is not a medical term. It is a type of synthetic plastic polymer material. PVC is commonly used in various industrial, commercial, and consumer products, such as pipes, cable insulation, clothing, and inflatable items.
If you have any medical concerns or questions, please provide them, and I would be happy to help you find a relevant answer.
I'm sorry for any confusion, but "Polyvinyls" is not a medical term. It is a chemical term that refers to polymers made from vinyl chloride, which is used in the production of various plastics and resins. If you have any questions about medical terms or concepts, I'd be happy to help with those!
'Alcohol drinking' refers to the consumption of alcoholic beverages, which contain ethanol (ethyl alcohol) as the active ingredient. Ethanol is a central nervous system depressant that can cause euphoria, disinhibition, and sedation when consumed in small to moderate amounts. However, excessive drinking can lead to alcohol intoxication, with symptoms ranging from slurred speech and impaired coordination to coma and death.
Alcohol is metabolized in the liver by enzymes such as alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). The breakdown of ethanol produces acetaldehyde, a toxic compound that can cause damage to various organs in the body. Chronic alcohol drinking can lead to a range of health problems, including liver disease, pancreatitis, cardiovascular disease, neurological disorders, and increased risk of cancer.
Moderate drinking is generally defined as up to one drink per day for women and up to two drinks per day for men, where a standard drink contains about 14 grams (0.6 ounces) of pure alcohol. However, it's important to note that there are no safe levels of alcohol consumption, and any level of drinking carries some risk to health.
Surgical sponges are absorbent, sterile materials used in medical procedures to soak up bodily fluids and help maintain a clean surgical field. They are typically made from gauze material and come in various sizes and shapes to accommodate different surgical needs. Surgical sponges are carefully counted before and after a procedure to ensure that none are accidentally left inside the patient's body.
A gelatin sponge, absorbable is a surgical implant material that is derived from animal collagen. It is prepared in the form of a sterile, compressed sponge which can be expanded with the addition of fluids. The sponge is designed to absorb and hold surgical drainage, promote healing by providing a framework for the growth of new tissue, and then gradually break down and be absorbed by the body over time. It is often used in neurosurgery, plastic surgery, and other surgical specialties for its hemostatic (bleeding control) and supportive properties.
Therapeutic embolization is a medical procedure that involves intentionally blocking or obstructing blood vessels to stop excessive bleeding or block the flow of blood to a tumor or abnormal tissue. This is typically accomplished by injecting small particles, such as microspheres or coils, into the targeted blood vessel through a catheter, which is inserted into a larger blood vessel and guided to the desired location using imaging techniques like X-ray or CT scanning. The goal of therapeutic embolization is to reduce the size of a tumor, control bleeding, or block off abnormal blood vessels that are causing problems.
Phenylmercury compounds are organic mercury salts that contain a phenyl group, which is a functional group consisting of a benzene ring with a hydroxyl group (-PHenyl-). These compounds were once used in various industrial and medical applications, such as antiseptics, preservatives, and vaccines. However, due to their toxicity and potential for bioaccumulation, the use of phenylmercury compounds has been largely discontinued.
Exposure to phenylmercury compounds can cause a range of adverse health effects, including neurological damage, kidney dysfunction, and developmental problems in children. Therefore, it is important to minimize exposure to these compounds and handle them with care if they are still used in certain applications.
I apologize for any confusion, but "Enbucrilate" is not a medical term or a medication that I am aware of. It's possible that there might be some misunderstanding or misspelling in the term. If you have more context or information about where this term came from, I may be able to provide a more accurate and helpful response.
However, if you are referring to "bucrilate" which is a type of polymer used in some medical applications such as wound dressings, then it is a substance that can absorb large amounts of water and create a gel-like barrier between the wound and the outside environment, helping to keep the wound moist and promote healing.
If you have any further questions or concerns, please don't hesitate to ask.
Ethiodized oil is a type of poppy seed oil that has been chemically treated with iodine. It is a highly dense form of iodine, which is used as a radiocontrast medium for imaging studies, such as X-rays and CT scans. The iodine in the ethiodized oil absorbs the X-rays and makes certain structures in the body more visible on the images. It is typically used to help diagnose conditions related to the gastrointestinal tract, such as ulcers or tumors.
It's important to note that the use of ethiodized oil as a radiocontrast medium has declined in recent years due to the development of newer, safer contrast agents. Additionally, there are potential risks associated with its use, including allergic reactions and kidney damage, so it is typically used only when other options are not available or have been determined to be inappropriate.
In chemistry, an alcohol is a broad term that refers to any organic compound characterized by the presence of a hydroxyl (-OH) functional group attached to a carbon atom. This means that alcohols are essentially hydrocarbons with a hydroxyl group. The simplest alcohol is methanol (CH3OH), and ethanol (C2H5OH), also known as ethyl alcohol, is the type of alcohol found in alcoholic beverages.
In the context of medical definitions, alcohol primarily refers to ethanol, which has significant effects on the human body when consumed. Ethanol can act as a central nervous system depressant, leading to various physiological and psychological changes depending on the dose and frequency of consumption. Excessive or prolonged use of ethanol can result in various health issues, including addiction, liver disease, neurological damage, and increased risk of injuries due to impaired judgment and motor skills.
It is important to note that there are other types of alcohols (e.g., methanol, isopropyl alcohol) with different chemical structures and properties, but they are not typically consumed by humans and can be toxic or even lethal in high concentrations.
Fixatives are substances used in histology and pathology to preserve tissue specimens for microscopic examination. They work by stabilizing the structural components of cells and tissues, preventing decomposition and autolysis. This helps to maintain the original structure and composition of the specimen as closely as possible, allowing for accurate diagnosis and research. Commonly used fixatives include formalin, glutaraldehyde, methanol, and ethanol. The choice of fixative depends on the specific type of tissue being preserved and the intended use of the specimen.
A foreign-body reaction is an immune response that occurs when a non-native substance, or "foreign body," is introduced into the human body. This can include things like splinters, surgical implants, or even injected medications. The immune system recognizes these substances as foreign and mounts a response to try to eliminate them.
The initial response to a foreign body is often an acute inflammatory reaction, characterized by the release of chemical mediators that cause vasodilation, increased blood flow, and the migration of white blood cells to the site. This can result in symptoms such as redness, swelling, warmth, and pain.
If the foreign body is not eliminated, a chronic inflammatory response may develop, which can lead to the formation of granulation tissue, fibrosis, and encapsulation of the foreign body. In some cases, this reaction can cause significant tissue damage or impede proper healing.
It's worth noting that not all foreign bodies necessarily elicit a strong immune response. The nature and size of the foreign body, as well as its location in the body, can all influence the severity of the reaction.
Chemoembolization, therapeutic is a medical procedure that involves the delivery of chemotherapy drugs directly to a tumor through its blood supply, followed by the blocking of the blood vessel leading to the tumor. This approach allows for a higher concentration of the chemotherapy drug to be delivered directly to the tumor while minimizing exposure to the rest of the body. The embolization component of the procedure involves blocking the blood vessel with various substances such as microspheres, gel foam, or coils, which can help to starve the tumor of oxygen and nutrients.
Therapeutic chemoembolization is typically used in the treatment of liver cancer, including primary liver cancer (hepatocellular carcinoma) and metastatic liver cancer. It may also be used in other types of cancer that have spread to the liver. The procedure can help to reduce the size of the tumor, relieve symptoms, and improve survival rates in some patients. However, like all medical procedures, it carries a risk of complications such as infection, bleeding, and damage to surrounding tissues.
Ophthalmic solutions are sterile, single-use or multi-dose preparations in a liquid form that are intended for topical administration to the eye. These solutions can contain various types of medications, such as antibiotics, anti-inflammatory agents, antihistamines, or lubricants, which are used to treat or prevent ocular diseases and conditions.
The pH and osmolarity of ophthalmic solutions are carefully controlled to match the physiological environment of the eye and minimize any potential discomfort or irritation. The solutions may be packaged in various forms, including drops, sprays, or irrigations, depending on the intended use and administration route.
It is important to follow the instructions for use provided by a healthcare professional when administering ophthalmic solutions, as improper use can lead to eye injury or reduced effectiveness of the medication.
In the context of medical and health sciences, particle size generally refers to the diameter or dimension of particles, which can be in the form of solid particles, droplets, or aerosols. These particles may include airborne pollutants, pharmaceutical drugs, or medical devices such as nanoparticles used in drug delivery systems.
Particle size is an important factor to consider in various medical applications because it can affect the behavior and interactions of particles with biological systems. For example, smaller particle sizes can lead to greater absorption and distribution throughout the body, while larger particle sizes may be filtered out by the body's natural defense mechanisms. Therefore, understanding particle size and its implications is crucial for optimizing the safety and efficacy of medical treatments and interventions.
Pharmaceutical preservatives are substances that are added to medications, pharmaceutical products, or biological specimens to prevent degradation, contamination, or spoilage caused by microbial growth, chemical reactions, or environmental factors. These preservatives help extend the shelf life and ensure the stability, safety, and efficacy of the pharmaceutical formulation during storage and use.
Commonly used pharmaceutical preservatives include:
1. Antimicrobials: These are further classified into antifungals (e.g., benzalkonium chloride, chlorhexidine, thimerosal), antibacterials (e.g., parabens, phenol, benzyl alcohol), and antivirals (e.g., phenolic compounds). They work by inhibiting the growth of microorganisms like bacteria, fungi, and viruses.
2. Antioxidants: These substances prevent or slow down oxidation reactions that can degrade pharmaceutical products. Examples include ascorbic acid (vitamin C), tocopherols (vitamin E), sulfites, and butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT).
3. Chelating agents: These bind to metal ions that can catalyze degradation reactions in pharmaceutical products. Ethylenediaminetetraacetic acid (EDTA) is an example of a chelating agent used in pharmaceuticals.
The choice of preservative depends on the type of formulation, route of administration, and desired shelf life. The concentration of the preservative should be optimized to maintain product stability while minimizing potential toxicity or adverse effects. It is essential to conduct thorough safety and compatibility studies before incorporating any preservative into a pharmaceutical formulation.
Drug compounding is the process of combining, mixing, or altering ingredients to create a customized medication to meet the specific needs of an individual patient. This can be done for a variety of reasons, such as when a patient has an allergy to a certain ingredient in a mass-produced medication, or when a patient requires a different dosage or formulation than what is available commercially.
Compounding requires specialized training and equipment, and compounding pharmacists must follow strict guidelines to ensure the safety and efficacy of the medications they produce. Compounded medications are not approved by the U.S. Food and Drug Administration (FDA), but the FDA does regulate the ingredients used in compounding and has oversight over the practices of compounding pharmacies.
It's important to note that while compounding can provide benefits for some patients, it also carries risks, such as the potential for contamination or incorrect dosing. Patients should only receive compounded medications from reputable pharmacies that follow proper compounding standards and procedures.