Mutational phospho-mimicry reveals a regulatory role for the XRCC4 and XLF C-terminal tails in modulating DNA bridging during classical non-homologous end joining.

XRCC4 and DNA Ligase 4 (LIG4) form a tight complex that provides DNA ligase activity for classical non-homologous end joining (the predominant DNA double-strand break repair pathway in higher eukaryotes) and is stimulated by XLF. Independently of LIG4, XLF also associates with XRCC4 to form filaments that bridge DNA. These XRCC4/XLF complexes rapidly load and connect broken DNA, thereby stimulating intermolecular ligation.

Structure-Based Virtual Ligand Screening on the XRCC4/DNA Ligase IV Interface.

The association of DNA Ligase IV (Lig4) with XRCC4 is essential for repair of DNA double-strand breaks (DSBs) by Non-homologous end-joining (NHEJ) in humans. DSBs cytotoxicity is largely exploited in anticancer therapy. Thus, NHEJ is an attractive target for strategies aimed at increasing the sensitivity of tumors to clastogenic anticancer treatments.

XRCC4/XLF Interaction Is Variably Required for DNA Repair and Is Not Required for Ligase IV Stimulation.

The classic nonhomologous end-joining (c-NHEJ) pathway is largely responsible for repairing double-strand breaks (DSBs) in mammalian cells. XLF stimulates the XRCC4/DNA ligase IV complex by an unknown mechanism. XLF interacts with XRCC4 to form filaments of alternating XRCC4 and XLF dimers that bridge DNA ends in vitro, providing a mechanism by which XLF might stimulate ligation.

A noncatalytic function of the ligation complex during nonhomologous end joining.

Nonhomologous end joining is the primary deoxyribonucleic acid (DNA) double-strand break repair pathway in multicellular eukaryotes. To initiate repair, Ku binds DNA ends and recruits the DNA-dependent protein kinase (DNA-PK) catalytic subunit (DNA-PKcs) forming the holoenzyme. Early end synapsis is associated with kinase autophosphorylation.

Cataract in the Kingdom of Morocco: indications for surgery and functional results.

Aim: To investigate the results of cataract surgery in different settings in the Kingdom of Morocco.

Method: At four separate health facilities, 100 consecutive patients undergoing ECCE cataract extraction for age-related cataract were examined pre-operatively and 6-8 weeks post-operative for changes in visual acuity.

Results: Thirty-four percent of patients (better eye acuity) and 95.

2002 global update of available data on visual impairment: a compilation of population-based prevalence studies.

Purpose: For the past 25 years, the WHO Programme for the Prevention of Blindness and Deafness has maintained a Global Data Bank on visual impairment with the purpose of storing the available epidemiological data on blindness and low vision. The Data Bank has now been updated to include studies conducted since the last update in 1994.

Methods: An extensive literature search was conducted in international and national scientific and medical journals to identify epidemiological studies that fulfilled basic criteria for inclusion in the Data Bank, namely a clearly stated definition of blindness and low vision, and prevalence rates derived from population-based surveys.

[Trachoma in Chad: results of an epidemiological survey].

A regional survey was carried out in Chad in 2000 and 2001 to estimate the prevalence and severity of trachoma. The main objectives were to describe the epidemiological pattern in terms of prevalence of inflammatory trachoma and blinding complications in two sub-samples of the population: children under 10 years of age and women over 14. Two strata were identified based on geographical criteria: two regions [Ouaddaï-Biltine, North-East] and [Lac-Kanem-Chari Baguirmi, North-West].

[Trachoma in Senegal: results of a national survey].

A national survey was conducted to determine the prevalence of trachoma in Senegal between February and July 2000. The methodology consisted of a cross-sectional survey based on random sampling with two levels of stratification in five areas or area groups. A total of 12,328 children under 10 years of age and 8753 women over the age of 14 years were examined from 150 clusters (30 clusters per stratum).

The prevalence and causes of blindness in the Sultanate of Oman: the Oman Eye Study (OES).

Aims: To estimate the magnitude and the causes of blindness through a community based nationwide survey in Oman. This was conducted in 1996-7.

Methods: A stratified cluster random sampling procedure was used to select 12 400 people.

[The quality of trichiasis surgery in the kingdom of Morocco].

In December 1998, a survey was carried out on the quality of trichiasis surgery, based on a random sample of 750 people chosen from the surgical records of 13 health centres of the provinces of Zagora and Errachidia (Kingdom of Morocco). Among those, 740 people were examined (participation ratio: 98.6%).

Refractive Error Study in Children: results from Mechi Zone, Nepal.

Purpose: To assess the prevalence of refractive error and vision impairment in school age children in the terai area of the Mechi zone in Eastern Nepal.

Methods: Random selection of village-based clusters was used to identify a sample of children 5 to 15 years of age. Children in the 25 selected clusters were enumerated through a door-to-door household survey and invited to village sites for examination.

Refractive Error Study in Children: sampling and measurement methods for a multi-country survey.

Purpose: The Refractive Error Study in Children was designed to assess the prevalence of refractive error and vision impairment in children of different ethnic origins and cultural settings.

Methods: Population-based cross-sectional samples of children 5 to 15 years of age were obtained through cluster sampling. Presenting, uncorrected, and best-corrected visual acuity, along with refractive error under cycloplegia, were the main outcome measures.

Cardiac surgery in adults and children without use of blood.

Since 1968, following Cooley's and Zubiate's group presentation, our team has been using extracorporeal circulation (ECC) with hemodilution without use of blood for priming of the circuit. Progressively this technique, that was only reserved to the Jehovah's Witnesses, became routine. Whereas in 1980, 30% of the patients operated by our group had not received any blood products during their stay in hospital, in the last few years, 1987-95, more than 80% of the patients could benefit from this technique.

The global impact of eye injuries.

Using data compiled from the ophthalmic literature and WHO's Blindness Data Bank, the available information on eye injuries from an epidemiological and public health perspective has been extensively reviewed. This collection of data has allowed an analysis of risk factors, incidence, prevalence, and impact of eye injuries in terms of visual outcome. However, most of the estimates are based on information from More Developed Countries (MDCs).

Prevalence of blindness and cataract surgery in Nepal.

Background: A national eye care programme was launched in Nepal in the early 1980s. The impact of this programme on blindness and cataract surgery prevalence was evaluated in two geographic zones.

Methods: People aged 45 years and older were sampled using a stratified cluster design.

[Prevalence and causes of blindness in the Tunisian Republic. Results of a national survey conducted in 1993. Tunisian Team on the Evaluation of Blindness].

Aims: to estimate the prevalence of visual impairment and blindness; to identify the major causes of visual impairment and blindness and to estimate their overall impact, particularly on cataracts.

Methods: We used a population-based method. A cluster sample was selected, with the number of households randomly selected from a community depending on the size of the population.

The Madurai Intraocular Lens Study. I: A randomized clinical trial comparing complications and vision outcomes of intracapsular cataract extraction and extracapsular cataract extraction with posterior chamber intraocular lens.

Purpose: The Madurai Intraocular Lens Study (MIOLS) was designed to compare safety, efficacy, and quality of life outcomes after either intracapsular cataract extraction with aphakic glasses (ICCE-AG) or extracapsular cataract extraction with posterior chamber intraocular lens (ECCE/ PC-IOL).

Methods: The Madurai Intraocular Lens Study was a nonmasked randomized controlled clinical trial conducted at a single hospital. Thirty-four hundred patients with age-related cataracts and having a best-corrected visual acuity less than or equal to 20/120 in the better eye were randomly assigned to either of the two cataract operative procedures.

[World Health Organization alliance for the elimination of trachoma].

Although trachoma has either decreased or disappeared in many Third World countries through socio economic development during the past forty years, it remains a major problem among the poorest communities, which is often ignored by decision-makers when setting priorities. Fortunately, recent developments will allow to overcome many of the past obstacles and to offer new opportunities for trachoma control programmes. WHO aware of this new favourable context for trachoma control has taken the leadership in mobilizing and coordinating trachoma control efforts through the creation of a WHO Alliance for the Global Elimination of Trachoma.

Blindness and low vision in southeast Turkey.

In preparation for the planning of a regional prevention of blindness programme, a population-based survey of blindness and eye disease was conducted in two provinces (Diyarbakir and Mardin) of southeast Turkey. A stratified cluster random sampling procedure was used to select 8,571 persons. The main objectives of the survey were to assess the population need for basic ophthalmic services, both in rural and in rapidly growing urban communities, and to secure baseline data for subsequent evaluation of the programme.