Biomedical subjects

M Sarmadi

Publications and source records attributed to M Sarmadi.

4 recordsLinked to original sources

PubMed2001

Immobilization of papain on cold-plasma functionalized polyethylene and glass surfaces.

Polyethylene and glass surfaces were functionalized under dichlorosilane-RF-cold-plasma environments and were employed as substrates for further in situ derivatization reactions and immobilization of papain. Surface functionality changes of RF-plasma-exposed surfaces were monitored under 40 kHz continuous discharge environments. The nature and morphology of derivatized substrates and the substrates bearing the immobilized enzyme were analyzed using survey and high resolution ESCA, ATR-FTIR, and fluorescence of chemical derivatization techniques. Spacer molecules intercalated between the substrates and the enzyme significantly increased the enzyme activity (comparable with the that of the free enzyme). Computer-aided conformational modeling of the substrate-spacer systems corroborated with experimental data indicated that an optimal distance might exist between the enzyme and the substrate. The activity of free and immobilized papain was monitored using benzoyl arginine ethyl ester assay. The pH data were recorded every 0.3 s over 25 min. The Michaelis-Menten kinetic constants were evaluated for immobilized enzymes. It was shown, that the immobilized papain retains most of its activity after several washing/assay cycles.

Arginine↗

PubMed2000

Recurrent aphthous stomatitis.

Etiology and Epidemiology: The Greek term aphthai was initially used in relation to disorders of the mouth and is credited to Hippocrates (460-370 BC). Today, recurrent aphthous ulceration, or recurrent aphthous stomatitis (RAS), is recognized as the most common oral mucosal disease known to human beings. Considerable research attention has been devoted to elucidating the causes of RAS; local and systemic conditions, and genetic, immunologic, and infectious microbial factors all have been identified as potential etiopathogenic agents (Table 1). However, to date, no principal etiology has been discovered. Epidemiologic studies indicate that the prevalence of RAS is between 2% and 50% in the general population; most estimates fall between 5% and 25%. In selected groups, such as medical and dental students, it has been observed with a frequency as high as 50% to 60%. The peak age of onset for RAS is between 10 and 19 years. After childhood and adolescence, it may continue throughout the entire human lifespan without geographic or age-, sex-, or race-related preference.

Administration, Topical↗

PubMed1998

Immobilization of alpha-chymotrypsin on oxygen-RF-plasma functionalized PET and PP surfaces.

In this contribution the immobilization of alpha-chymotrypsin on plasma activated PET and PP surfaces is investigated. The 'anchoring' C=O groups on polymer surfaces were created under RF-O2-plasma environments. The identity and relative concentrations of plasma-created functionalities were evaluated using survey and high resolution X-ray photoelectron spectroscopy, and differential attenuated total reflectance-FTIR spectroscopy. Surface morphology changes of plasma-exposed substrates were analyzed by atomic force microscopy. Enzyme assays were performed from both virgin and plasma modified samples which underwent the immobilization procedure. It was demonstrated that cold-plasma technique is suitable for generating functional, synthetic polymeric surfaces which can initiate enzyme coupling reactions. It also has been shown that the activity of the immobilized enzyme is lower in comparison to the free enzyme. Reduced conformational mobility resulting from multiple-point coupling process might be responsible for this behavior.

Argon↗

PubMed1997

A comparison of segmental and marginal bony resection for oral squamous cell carcinoma involving the mandible.

PURPOSE: This study reviews the accuracy of preopertive diagnosis of mandibular invasion by oral squamous cell carcinoma and assesses the role of marginal resection of the mandible in its treatment. PATIENTS AND METHODS: A retrospective study of a 5-year cohort of 46 patients who underwent mandibular resection for previously untreated oral squamous cell carcinoma was done. Data evaluated included age; sex; site and stage of cancer; preoperative clinical, panoramic, and computed tomography (CT) evaluations; and histologic findings on the resection specimen. The type of mandibular resection (segmental vs marginal) and treatment outcome also were compared. RESULTS: Clinical examination, panoramic radiographs, and CT scans were 78.5% to 82.6% accurate in diagnosing mandibular invasion by squamous carcinoma. Clinical examination and panoramic radiographs are more sensitive than CT scans (86.6% vs 53%), but CT scans were more specific (92.5% vs 80%). The mandible was involved in 65% of patients with segmental resection and 7.6% of patients who had a marginal resection. Nineteen percent of the patients in the marginal resection group died of their oral cancer, two of five patients with local recurrence. Ten percent of patients in the segmental resection group died of oral cancer; no local recurrences were seen. CONCLUSION: There is no completely accurate method of diagnosing bony invasion of the mandible by oral squamous cell carcinoma. A combination of clinical examination, plain radiographs, and computed tomography (CT) scans may improve the diagnosis. Marginal resection is best reserved for cancers close to the bone with no invasion, minimal cortical invasion, or with early "arrosive" invasion. It is best in the symphysis region. Careful case selection will allow a favorable oncologic outcome with preservation of the mandibular contour.

Adult↗