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Biomedical subjects

C G Burkhart

Publications and source records attributed to C G Burkhart.

At least 19 recordsLinked to original sources
PubMed2000

In pursuit of ceruminolytic agents: a study of earwax composition.

OBJECTIVE: To assess the protein and simple sugar content of earwax in pursuit of better ceruminolytic agents. STUDY DESIGN: Collected earwax specimens were tested in several media for dissolution before being analyzed for amino acid and carbohydrate content. PATIENTS: The samples were obtained from eight random patients requiring ear plug removal. RESULTS: The amino acid composition differs considerably from hair and stratum corneum of glabrous skin. Sugar analysis revealed high levels of galactosamine and galactose. CONCLUSIONS: This analysis of proteins and carbohydrates further characterizes earwax. Future ceruminolytic agents must dissolve lipid, keratin, and a monolayer of lipid covalently bound to the epidermal cells, which encourages cellular aggregation.

Amino Acids↗
PubMed2000

Scanning electron microscopic examination of the egg of the pubic louse (Anoplura: Pthirus pubis).

OBJECTIVE: The purpose of the study was to examine the eggs of pubic lice with consideration of their clinical relevance. STUDY DESIGN: Pubic lice eggs were examined by scanning electron microscopy (SEM). RESULTS: The egg is totally encased by a proteinaceous sheath, except for the operculum, by which oxygen exchange occurs. CONCLUSION: Pubic lice have proved resilient to human therapies through the ages. The anatomical target of topical insecticides for ovicidal kill is the operculum and the protective layers that surround the developing embryo. More research into these structures is warranted.

Animals↗
PubMed2000

Effects of benzoyl peroxide on lipogenesis in sebaceous glands using an animal model.

BACKGROUND: Benzoyl peroxide is the most widely used topical agent for acne since the 1960s. Concomitant treatment of benzoyl peroxide with oral, or topical antibiotics diminishes the multiplication of antibiotic-resistant strains of Propionibacteria acnes. Besides being antibacterial, the chemical also functions as a peeling agent, has comedolytic activity, reduces free fatty acid levels, and is touted to be sebosuppressive. OBJECTIVE: The purpose was to determine the ability of topically applied benzoyl peroxide to suppress lipogenesis of the sebaceous glands. METHODS: The data were obtained employing an animal model for human sebaceous glands, namely, the flank organs of female golden Syrian hamsters. RESULTS: Our results reveal no inhibition of lipogenesis in sebaceous glands by topical application of benzoyl peroxide. CONCLUSION: Despite many functions beneficial in acne therapy, benzoyl peroxide does not possess sebosuppressive capabilities. With the advent of water-soluble organic peroxides revealing similar antimicrobial activity to benzoyl peroxide, all therapeutic parameters (save for sebosuppression) will need to be assessed to weigh the benefits of these second-generation acne-fighting peroxides.

Acne Vulgaris↗
PubMed2000

Scanning electron microscopy of adult head lice (Pediculus humanus capitis) with focus on clinical implications.

BACKGROUND: The incidence of head lice infestations in North America is escalating with an estimated 12 million cases of head lice per year despite the existence of insecticidal therapies. OBJECTIVE: To evaluate certain characteristics of the human head louse, including their chitinous structure, nymphal developmental stages, legs with claw adaptations, antennae with sensory perceptions, and spiracles by which oxygen exchange occurs, for assessment of possible means to control the spread and growth of this insect. METHODS: Scanning electron-microscopic examination of head lice was performed. RESULTS: Newer treatments of head lice must acknowledge defense mechanisms that are based on anatomic structure and physiologic characteristics, details of louse transmission, and the insects' ability to 'resurrect' after sham death. CONCLUSIONS: An understanding of lice entomology is essential in the pursuit of novel means to control the lice epidemic.

Animals↗
PubMed2000

An epidemiologic and therapeutic reassessment of scabies.

Scabies is a highly contagious infestation that causes considerable discomfort. Newer information concerning therapeutics and epidemiologic dogma needs assessment. An epidemiologic evaluation of available world data is analyzed, as well as an assessment of therapeutic alternatives. Using epidemiologic techniques, the following points are proven: scabies is not primarily a sexually transmitted disease; 30-year cycles of scabies do not exist; scabies spreads in households and neighborhoods in which there is a high frequency of intimate personal contact or sharing of inanimate objects; and fomite transmission is a major factor in household and nosocomial passage of scabies. Epidemiologic evaluation proves the necessity of fomite precautions and of treatment of asymptomatic family members and physical contacts of all cases of scabies. Single oral-dose therapy of ivermectin (Stromectol) appears to be the treatment panacea for this infestation.

Animals↗
PubMed1999

Scanning electron microscopy of human head louse (Anoplura: Pediculidae) egg and its clinical ramifications.

Pediculosis affects more elementary school students than all other communicable childhood diseases combined, excluding the common cold. The current study using scanning electron microscopy visualized operculums through which developing embryos received oxygen, as well as fracture lines within the adherent sheath by which the egg is attached to the hair. Using microscopic techniques, including freeze-fracturing, the mode of attachment of the sheath to the hair follicle was observed, in addition to the existence of several inner membranes enclosing the embryo within the egg structure. The chemical nature of the sheath is also analyzed using electron dispersive x-ray analysis.

Animals↗
PubMed1999

Histochemical analysis of the nit of Pediculus humanus capitis (Anoplura: Pediculidae).

Histochemical stainings of head louse nits were performed and observations indicated that the nit sheath was nonchitinous. One discernable membrane composed of hyaluronic acid was established that encircled the larvae within the egg. The structural framework of the egg included a definite lattice around each aeropyle of the operculum, through which oxygen exchange occurred.

Animals↗
PubMed1999

School nurses' perceptions of and experiences with head lice.

Researchers examined school nurses' perceptions of head lice, perceived self-efficacy in dealing with head lice, and personal experience in reducing head lice problems. Survey data from a two-wave mailing from 382 school nurses found most nurses supported a "no-nit" rule of forced absenteeism of any child with nits in their hair (60%). They perceived OTC treatments for head lice as very effective in killing adult lice (66%), and 9% perceived them as not effective. Nurses had a high efficacy expectation regarding their ability to control head lice (63%), and they had high outcome expectations regarding the results of their work with students and families of students (66%). Most nurses received their information about head lice from professional journals (76%) and professional conferences/conventions (62%).

Adult↗
PubMed1999

Acne: a review of immunologic and microbiologic factors.

Acne vulgaris is a self-limiting skin disorder seen primarily in adolescents, whose aetiology appears to be multifactorial. The four main aetiological factors are hypercornification of the pilosebaceous duct, increased sebum production, colonization with Propionibacterium acnes, and subsequently the production of inflammation. Considerable investigation has addressed the immunologic reaction to extracellular products produced by the acne-causing organism, P acnes. The immunologic response involves both humoral and cell-mediated pathways. Further research should clarify the role of complement, cytotoxins, and neutrophils in this acne-forming response.

Acne Vulgaris↗
PubMed1999

Propionibacterium acnes: interaction with complement and development of an enzyme-linked immunoassay for the detection of antibody.

OBJECTIVE: To characterize the immune response to Propionibacterium acnes in acne patients. DESIGN: Comparison of serologic responses in acne and normal patients using counterimmunoelectrophoresis for antibody and an enzyme-linked immunosorbent assay (ELISA) to detect immunoglobulin G (IgG) antibody. SETTING: The serum of acne and nonacne patients from the Dermatology Clinic at the Medical College of Ohio was utilized for analysis. RESULTS: Using counterimmunoelectrophoresis, antibody was detected in 13 of 20 acne patients. The antigen was detectable as an anion in the barbital buffer at pH 8.2, strongly suggesting a carbohydrate component. By ELISA, the antibody proved to be IgG, and the bacteria and its water-soluble fractions were capable of fixing complement. CONCLUSIONS: The primary instigator of inflammation in acne vulgaris is an immunologic reaction to extracellular products of P. acnes. The immunologic response involves both humoral and cell-mediated pathways. The antibodies to P. acnes have not been characterized fully, although they are largely of the IgG class. We have further characterized the dominant antigen to have a carbohydrate component.

Animals↗