MicroscopesBlog: Expert's reviews, news, notes on Microscopes, Centrifuges, Lab Coats, Pipettes, Lab Safety, & more Lab Products!
Friday, February 26, 2010
Antiviral Drugs
It's very difficult to kill something that isn't dead. This is the challenge when developing antiviral drugs. Whether or not a virus is alive is a great issue of debate among scientists. Amantadine was the first licensed antiviral drug in the U.S. but how it works is not well known. It has limitations in preventing influenza. Other antiviral drugs for the the treatment of the flu ar zanamivir (Relenza) and oseltamivir phosphate (Tamiflu). Both of these drugs are inhibitors of neuraminidase, an enzyme critical for a virus to continue to reproduce. Because a virus is a biochemical mass of protein and nucleic acid, most antiviral drugs are synthetic nucleosides that interfere with DNA or RNA sysnthesis. The HIV virus uses an enzyme called reverse transcriptase to reproduce itself. Drugs such as zidovudine, didanosine, and zalcitabine block the activity of this enzyme. Companies like Axygen, Beckman Coulter, and Whatman provide products used in antiviral drug research.
Posted by Paul at 6:48 AM Read Article 0 comments 
Friday, February 19, 2010
Antifungal Drugs
Antifungal drugs are used to fight fungal infections. Fungi are eukaryotic organisms as opposed to prokaryotic such as bacteria. This makes it harder to fight fungal infections human cells are eukaryotic as well. Anti-fungal drugs have side effects due to the fact that they are affecting host cells as well as fungi. Anti-fungal drugs are divided into different classes. Polyenes include amphotericin B, which is the most commonly used drug in this class. Polyenes damage fungal membranes by combining with membrane sterols. Amphotericin B is used for histoplasmosis, coccidioidomycosis, and blastomycosis (systemic fungal infections.) The next class of antifungal drugs is imidazoles and triazoles. This class includes miconazole and clotrimazole which are used agatinst cutaneous fungal infections. Other antifungal drugs interfere with DNA and RNA synthesis and come in the form of fatty acids. Antifungal drugs are specific and effective but also have side effects that antibacterial drugs don't. BD, Biohit, and Beckman Coulter supply products used in antifungal drug research.
Friday, February 12, 2010
Antimicrobial Drug Action
Antimicrobial drugs can be compared to laser guided missiles. They are designed to seek and destroy a very specific target. These drugs destroy bacteria in different ways depending on what biological process they inhibit within the bacteria. Some drugs inhibit the synthesis of the cell walls of bacteria. Because bacteria contain a substance called peptidoglycan, drugs that interfere with cell wall synthesis do not affect the host cells. Penicillin might be the most well known inhibitor of cell wall synthesis. Antimicrobial drugs can also target the ribosomes in bacteria because they differ greatly from ribosomes of eukaryotic cells. Drugs can interfere with protein synthesis by affecting the ribosome. Some drugs are polypeptides that affect the permeability of the cell membrane which causes the loss of metabolites. Sulfa drugs competitively inhibit the synthesis of folic acid which is a vitamin synthesized by bacteria but not humans. Alconox, Binder, and Biohit make products used in laboratories where antimicrobial drugs are used and researched.
Monday, February 08, 2010
MWCO Membrane
Ultrafiltration involves filtration at the molecular weight level. Ultrafiltration can involve membranes, centrifuge tubes, and dialysis tubing. MWCO membranes allow molecules smaller than the molecular weight cut off to pass through while molecules larger than the molecular weight cut off are retained. MWCO refers to the Molecular weight in Daltons (or kilo Daltons kD )at which 90% of the globular proteins will be retained. These membranes are available in many forms and materials. Disc membranes materials are polyethersulfone (Pall Life Sciences) and cellulose ester (Spectrum Medical Industries).
Other devices include: Tangential flow membrane cassettes (Pall USA). Whatman and Sartorius Stedim are manufacturers of ultrafiltration centrifuge filters. Ultrafiltration dialysis uses laboratory dialysis tubing from manufacturers like Spectrum Medical.
Friday, February 05, 2010
Antimicrobial Drugs
Antimicrobial drugs belong to a class of chemotherapeutic agents used to treat infectious diseases. Antimicrobial drugs act within the host and target the harmful organism without affecting host cells. This is known as selective toxicity. Synthetic drugs are synthesized in the laboratory while antibiotics are produced by microorganisms. Dr. Paul Ehlrich of Germany discovered what he considered a "magic bullet" that would destroy harmful microorganisms but not the host. He eventually found salvarsan, an arsenic derivative, that was useful against syphilis. Penicillin is an antibiotic and was first discovered in 1928 by Alexander Flemming. Antimicrobial drugs can be classified by their range of efficacy. If a drug affects few bacteria it is known as a narrow spectrum drug as opposed to broad spectrum drugs that affect a wide range of bacteria. Antibiotics may eliminate normal microbiota or "good bacteria" and allow opportunistic pathogens to flourish. This is known as a superinfection. Axygen, Bel-Art, and Kimberly Clark all supply products used in antimicrobial drug research.
Tuesday, February 02, 2010
The Princess and the Frog
©2009-2010 *Spiritwollf. Okay when we think of frogs we probably think of the old fairytale or the new Disney Movie, The Princess and the Frog; however there is another side to frogs that we look at in Science Class at school, the process is called dissecting a frog. For some not so glamorous as looking at the frog in this photo. The materials that you need for dissecting a frog in class are, safety goggles, dissecting kit, dissecting pins, laboratory gloves, lab apron, or lab coat, tweezers, scissors, dissecting probe, preserved frog, dissection tray, and a magnifying lens. Dissection of a frog is not that bad as long as you have the right tools which I mentioned above. Its a great first science lab project. Your objective is to locate and describe the organs found in the frog. You will be asked to name locate and identify the organs that make up the various systems of the frog and probably compare the frogs organs to human organs. Did you know that frogs are amphibians? They can live in water and on land. Either way you look at it, each example the Princess and the Frog fairytale tells a story about a prince that has been cursed and turned into a frog, the only way he can be freed of his curse is to be kissed by the Princess, and the Science Lab project of dissection of the frog also tells us a story through dissection and examination. This is great time in your life, Science labs are a fun time! Pay attention in class and take notes! All will go well for you.Monday, February 01, 2010
Membrane Filtration in the Lab
Membrane filters are surface or screen filters. Only the surface is used to filter the solution. Typical pore sizes range from 0.2um (micrometers) to 1.0 um. Membrane filters can be made of cellulose (cellulose acetate, cellulose nitrate), Nylon, Polyethersulfone (PES) PTFE (Teflon*)... Membrane filtration is used very often for sample preparation to ensure that particles above a certain size do not pass through to equipment. Track etched membranes are used to trap cells
of interest to be later studied under a micoscope. Teflon* membrane filters are used with acidic or basic samples and samples in strong solvents. PTFE membrane filters are also used to filter air vents where sterility must be mantained such as in fermentation vessels. Membrane filters are also supplied as syringe filters or capsule filters eliminating the need for a filter holder. Whatman, Pall and Nalge Nunc are some of the manufacturers of membrane filters.*Teflon is a trademark of DuPont Corp.