All posts by dvivanov

Case Report: Sjogren’s Syndrome

By David Ivanov, Biochemistry and Molecular Biology, 2015

Sjogren’s syndrome, like other autoimmune diseases, can be difficult to diagnose definitively, and often relies on a handful of signs and symptoms that can vary substantially from case to case. The only signs considered markers for Sjogren’s are anti-SSA and anti-SSB antibodies, and while anti-SSB is more specific, elevated levels of anti-SSB are actually less common in patients with Sjogren’s syndrome than anti-SSA, leading to some ambiguity in diagnosis.

A seventeen year old female patient presented with a large, soft, sublingual cyst on the left side of the floor of her mouth. While she reported no pain, the cyst was first spotted about a year earlier, and had been growing steadily. Visible swelling was observed on the left side of her face under her jaw line. Surgery was performed to remove the cyst, and an adjacent salivary gland was removed as well. The otorhinolaryngologist took a tissue sample, and histology confirmed a benign growth. The surgeon ordered a blood panel to evaluate antibody levels that might indicate an autoimmune disease. The patient’s serum was negative for rheumatoid factor, anti-SSB antibodies, and anti-nuclear antibodies. However, she was positive for anti-SSA antibodies, with a level of 50 U/ml. Bacterial cultures were negative for oral infection, and an X-ray was negative for sarcoidosis. Patient was discharged after surgery with no medications indicated, as she was not experiencing any other symptoms.

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What is LASIK?

By David Ivanov, Biochemistry and Molecular Biology, 2015

LASIK, or laser-assisted in situ keratomileusis, is a surgical procedure commonly used to correct for visual defects or lack of visual clarity. Commonly referred to as laser eye surgery, LASIK is a type of surgery that is used to alleviate visual loss associated with common defects of the eye, such as myopia (nearsightedness), hypermetropia (farsightedness), and astigmatism. Astigmatism, like near and far-sightedness, can be caused by the irregularity in shape of the cornea that leads to blurred vision. For all three cases, corneal remodeling via LASIK can be performed (Thomson, 2015).

The cornea is the outermost layer of the eye, the transparent part that one can touch, and upon which contact lenses are placed. It is responsible for most of the focusing power, and thus is a common culprit in visual defects of the eye. The cornea focuses the light reflected into the eye, through the lens and onto the the retina at the back of the eye, which senses light and converts it to nerve impulses, and transmits the resulting image to the brain for processing. This then produces the image that we ‘see’. While the retina is the part of the eye that is light-sensitive and is responsible for transmitting the image to the brain, the cornea, along with the lens, must focus light reflecting off of three dimensional surfaces so that they strike onto the anterior, or front part of the retina. Without this precise focusing of light rays directly onto the retina, the brain generates a blurred image (NKCF 2014).

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Abundance Estimates And Vegetation Preferences Of The Suisun Song Sparrow In The Interior And Along Edges Of Impounded Wetlands

By Debi Fanucchi, Oscar Garzon, Julia F. Herring, and Kevin M. Ringelman

ABSTRACT

The Suisun Song Sparrow (Melospiza melodia maxillaris) is a subspecies of Song Sparrow that is endemic to the Suisun Marsh of California. It is listed as a state species of special concern by the California Department of Fish and Wildlife due to its restricted range, small breeding population, and susceptibility to encroaching human development. The Suisun Marsh ecosystem is highly altered, and is comprised of both natural tidal wetlands and impounded wetlands that are cut off from the natural tidal cycle. Suisun Song Sparrows are believed to prefer natural tidal wetlands, but there is a lack of information on sparrow densities and habitat associations in impounded wetlands. To address this knowledge gap, we examined the abundance and habitat preferences of Suisun Song Sparrows in an impounded and heavily managed wetland complex.  We conducted surveys at seven sites within interior managed (impounded) wetlands, and seven sites along edges between tidal and impounded wetlands. We found significantly more birds in interior sites than at edge sites, but within edge habitat, abundances were higher on the tidal side of the levee. We found that Song Sparrows used tall vegetation in greater proportion than its abundance, and specifically preferred bulrush and common reed as calling perches. Interior sites contained relatively less of this preferred vegetation than edge sites, suggesting that beneficial habitat heterogeneity in interior sites, and/or deleterious edge effects along the dikes may be important drivers of abundance. In the face of sea-level rise and shifting conservation priorities, many managed wetlands are expected to be converted back into fully tidal systems, and our results provide an important baseline for future research on the effects of tidal restoration.

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New Target For Alzheimer’s Treatment

By David Ivanov, Biochemistry and Molecular Biology, ’15

A group of researchers studying brain cells have found a new potential target for pharmacological therapies that may help treat Alzheimer’s disease. Beta amyloid plaque, which appears to be a toxic build up of fragments of amyloid precursor protein (APP) in the brain, has long been associated with Alzheimer’s disease, and has been one of the major targets for Alzheimer’s treatment. Amyloid precursor protein plays an important role in the brain, and when this protein is broken down in nerve cells the toxic byproduct beta amyloid is formed. Continue reading New Target For Alzheimer’s Treatment

Engineering Hepatitis Virus-like Particles for Oral Vaccine Delivery

By David Ivanov, Biochemistry ’15

Oral vaccines are known to be a convenient and effective method for treatment or prevention of diseases caused by pathogenic microorganisms. The difficulty of developing such vaccines is due to the often inhospitable environment of the stomach and intestinal tract because of low pH, or acidity, as well as enzymes that can digest or destroy biological molecules. Using a virus-like particle to deliver the vaccine is an advantageous method for getting around these and other barriers in the host organism.

A virus-like particle, or VLP, is a biological particle that resembles a virus, but contains no genetic information and thus cannot infect host cells. VLP’s can be formed by inserting and expressing just the genes for creating the viral capsid, which is a shell made up of protein subunits that protects the infectious genetic information in wild-type, or normal, viruses. The expressed capsid proteins can then self-assemble into the VLP. The capsid also has domains, or structural areas, that are responsible for recognizing suitable host cells to infect and inserting the viral genome.

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