Expression of MHC class II antigens by conjunctival epithelial cells in trachoma: implications concerning the pathogenesis of blinding disease

Article Abstract:

Trachoma, an eye infection caused by the organism Chlamydia trachomatis (C. trachomatis), is a leading cause of blindness in many parts of the world and affects an estimated 500 million people, causing blindness in 7 million. In the initial stages, the membranes that surround the eyes and line the eyelids (conjunctiva) become inflamed (conjunctivitis). After the inflammation subsides, scar tissue impairs the functioning of the eyelids and tear ducts, causing blindness because of repeated injury to the cornea (the covering of the front part of the eye). The reasons scarring occurs are not known, nor is it understood why it progresses even when C. trachomatis can no longer be isolated. Normally, foreign proteins (antigens) are presented to cells of the immune system for destruction only after they bind to special molecules that are members of the class II major histocompatibility complex (MHC). MHC molecules are located on the surfaces of certain types of cells in the body, such as cells that line the intestine. If MHC molecules are expressed by other cell types, the immune system may (erroneously) attack those cells, killing them. It is possible that the scar tissue formation associated with trachoma is the result of the appearance (expression) of MHC molecules on cells of the conjunctiva, leading to destruction of the membranes. This was explored in a study in Gambia in which the eyes of 40 children with active trachoma and 38 children without active disease were examined. Laboratory tests were used to identify MHC molecules and the presence of chlamydial antigen. Results showed that MHC molecules were present in conjunctival cells from 28 of the 40 active-disease subjects and in 10 of the 38 non-active-disease patients, a statistically significant difference. Expression of these molecules was seen in 12 of the 14 active-disease subjects who also had chlamydial antigen, and in 2 of the 3 non-active-disease subjects with antigen; the presence of the antigen was not associated with the expression of MHC molecules. It is possible that MHC molecules appear on conjunctival cells prior to the development of trachoma and remain even after the disease has resolved. Their role in trachoma remains uncertain. (Consumer Summary produced by Reliance Medical Information, Inc.)

Infection, Causes of, Physiological aspects, Blindness, Chlamydia trachomatis, Eye, Major histocompatibility complex, Trachoma

---

Appropriate use of helicopter to transport trauma patients from incident scene to hospital in the United Kingdom: an algorithm

Article Abstract:

The use modes of transport in the United Kingdom to move the trauma patients from the site of incident to the hospital is very complex due to hazardous environmental conditions, aggressive crowd, and poor weather conditions. The use of helicopters to transport trauma patients in the U.K. is discussed and a simple algorithm to assist frontline ground ambulance personnel, air ambulance crews, and doctors select the most appropriate mode is presented.

United Kingdom, Goods & services distribution, Analysis, Usage, Emergency medical services, Transportation, Patients, Helicopters, Transport of sick and wounded, Medical transportation

---

Rate of decline of percentage CD4+ cells is faster in HIV-1 than in HIV-2 infection

Article Abstract:

In Gambia, Africa, HIV-1 causes more sickness and death than HIV-2 even though HIV-2 is more widespread in this community. HIV-1 and HIV-2 are two different strains of HIV. In a study of 310 patients, those with HIV-1 had faster disease progression and faster decreases in immune system function.

Statistical Data Included, HIV infection, HIV infections, HIV (Viruses), HIV

Similar abstracts:

• Abstracts: Unusual presentation of extranodal peripheral T-cell lymphomas with multiple paraneoplastic features
• Abstracts: Rice-based oral electrolyte solutions for the management of infantile diarrhea. Magnesium-induced diarrhea and new insights into the pathobiology of diarrhea
• Abstracts: Impact of tubal sterilization and vasectomy on female marital sexuality: results of a controlled longitudinal study
• Abstracts: Cholera outbreak - Peru, Ecuador, and Colombia. Update: cholera - Western Hemisphere, and recommendations for treatment of cholera
• Abstracts: Weaning from mechanical ventilation. Effect on the duration of mechanical ventilation of identifying patients capable of breathing spontaneously

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.