Is phenytoin contraindicated in patients receiving cranial irradiation ?

Three recent publications have reported the development of erythema multiforme and Stevens-Johnson syndrome in patients receiving cranial irradiation and sodium phenytoin. Some authors have recommended that patients receiving whole brain radiation therapy and who have had seizures should not be prescribed phenytoin but an alternative anticonvulsant. This article reviews the current literature pertaining to the development of this potentially lethal complication in patients receiving whole brain radiation and phenytoin, with reference to the single recorded case of Stevens-Johnson syndrome in a patient receiving cranial irradiation and phenytoin in Auckland, New Zealand. While the clinical picture in the 16 patients reported in the literature and the current case report differed from the classical form of erythema multiforme, a similar pattern of presentation and outcome appeared in all patients reviewed, suggesting that the combination of phenytoin, cranial irradiation and the gradual reduction of concomitant steroids seem to lead to the development of erythema multiforme and/or Stevens-Johnson syndrome. The data presented, although sparse, suggest that phenytoin should not be prescribed in patients receiving cranial irradiation.     

Volumetric shrinkage of composites using video-imaging

Objective. This study involves investigation of the use of video-imaging for measurement of volumetric shrinkage of composites.Methods. Six composites were tested for volumetric shrinkage using video-imaging. The volumetric shrinkage was measured using the single- and multi-view volumetric reconstruction modes. All composites were cured using a VIP(TM) curing light for 40s at 500mW/cm(2). Dynamic shrinkage was measured using the single-view mode with a red filter placed over the detector opening.Results. Analysis of the volumetric shrinkage values by a one way ANOVA for each composite showed no difference for the single- and multi-view measurement mode. The shrinkage values determined by video-imaging were compared to those measured for the same composites by mercury dilatometry by one way ANOVA followed by a paired comparison using the Bonferroni method.Conclusion. The video-imaging technique gives reproducible results for volumetric shrinkage of composites comparable to those measured by dilatometry.     

Epidemiological and clinical aspects of paediatric HIV infections in Albert-Royer Paediatric Hospital (Dakar, Senegal)]

Human Immunodeficiency Virus (HIV) infection prevalence rate is estimated at 1.4% in Senegal, and about 3,000 children could be infected. HIV positive children are followed up since 2000 in Albert Royer Hospital (Dakar, Senegal). OBJECTIVES: To describe clinical and epidemiological aspects of HIV paediatric infection, and to evaluate the implementation of high active antiretroviral therapy in HIV positive children in our country. POPULATION AND METHODS: Over a period of three years, the medical reports of 98 infected patients have been collected, 96% with HIV 1 infection. RESULTS: Most of the patients had a maternally transmitted HIV infection (99%). At their enrollment, the median age was 60 months; malnutrition (79%), persistent lymphadenopathy (65%) and skin lesions (64%) were the common clinical manifestations. Thirty-nine percent of the patients were in class C (CDC) and 81% had CD4 cell count< or =25%. Median viral load were 421,852 copies/ml at presentation. Seven infants had a rapid progressive disease with encephalopathy. Thirty-six patients received high active antiretroviral therapy with high observance and good tolerance. CONCLUSION: This study allowed to define clinical and biological profile of paediatric HIV infection in our country and to update the implementation of high active antiretroviral therapy.     

Radiosensitivity of DNA in a specific protein-DNA complex: the lac repressor-lac operator complex

PURPOSE: To calculate the probability of radiation-induced frank strand breakage (FSB) at each nucleotide in the Escherichia coli lac repressor-lac operator system using a simulation procedure. To compare calculated and experimental results. To asses the contribution of DNA conformational changes and of the masking by the protein to DNA protection by the repressor. MATERIALS AND METHODS: Two structures of the complex were extracted from the PDB databank: crystallography- and NMR-based structures. Calculations were made of the accessibility of the atoms mainly involved in strand breakage (H4' and H5') to O&Hdot; and of the FSB probabilities, along: (1) DNA in the complex; (2) DNA in the complex depleted of the repressor; and (3) a linear DNA having the same sequence. An 80bp fragment bearing the operator was irradiated alone or in presence of the repressor. The relative probabilities of FSB at each nucleotide were determined using sequencing gel electrophoresis. RESULTS: Calculations predict modulation of the accessibility of H4' and H5' atoms and of the probabilities of FSB along the DNA fragments of complexes. This is due to the protein-induced conformational change and to masking by bound protein. The best agreement with the experimental FSB was observed for calculations that use the crystallography-based structure. CONCLUSIONS: For specific DNA-protein complexes, our calculations can predict the protein radiolytic footprints on DNA. They show the significant contribution of the protein-induced DNA conformational change to DNA protection.     

Appropriate training and retention of community doctors in rural areas: a case study from Mali

Background  

While attraction of doctors to rural settings is increasing in Mali, there is concern for their retention. An orientation course for young practicing rural doctors was set up in 2003 by a professional association and a NGO. The underlying assumption was that rurally relevant training would strengthen doctors' competences and self-confidence, improve job satisfaction, and consequently contribute to retention.     

Cytogenetic and molecular genetic analysis of tumorigenic human bronchial epithelial cells induced by radon alpha particles

To establish a cell culture model for lung carcinogenesis, independent populations of the human papillomavirus 18-immortalized human bronchial epithelial cell line BEP2D were treated with high linear energy transfer radon-simulated alpha-particles, expanded and xenotransplanted into Nu/Nu mice. Six independent cell lines were established from tumors that developed from three separate radiation treatments as follows: treatment (Tx) 1 (30 cGy--two doses), H2BT, Tx 2 (30 cGy-- single dose), R30T1L, R30T2 and R30T3L, Tx 3 (30 cGy--single dose), H1ATN and H1ATBA1. Cytogenetic analysis revealed common changes in all tumor lines: loss of the Y chromosome (ch), one of three copies of ch8, one of three copies of ch14, and one of two copies of ch4p16-pter and ch11p15-pter. Analysis of polymerase chain reaction-amplified short tandem repeats of informative loci confirmed the loss of chY in all lines and loss of heterozygosity (LOH) at eight loci spanning the length of ch8 in all lines from Tx's 1 and 2. Our data support previous studies indicating the presence of tumor suppressor genes on ch8. LOH also was confirmed on ch14 at locus D14S306 in all cell lines from Tx 2 and in one of two lines from Tx 3. This region, 14q12-q13, may contain changes in one of the five known somatostatin receptor genes (SSTR1). No LOH was detected at any of the informative loci tested for on ch4 or ch11.      

Mycobacterial infection in an inner city children's hospital

Childhood tuberculosis is perceived by many as a disease of the past. Experience in a children's hospital serving a deprived population suggested that tuberculosis and other mycobacterial infections were not declining in clinical practice. Fifty three tuberculous and 11 atypical mycobacterial infections were identified between 1978 and 1992. There was no decline in tuberculosis and nine of the 11 atypical infections occurred in the last five years. Altogether 40% of cases of tuberculosis were in non-Asian children; 32% had arrived in the UK or visited family overseas in the previous year; and 38% had a history of tuberculosis contact, usually a close adult relative. Nationally, the previous decline in tuberculosis in all ages has reversed. In the local health districts in London's east end, childhood tuberculosis has also stopped declining and seems to be increasing. It is regrettable that BCG vaccination has been abolished by some districts in the UK, against current recommendations. Childhood tuberculosis is still common in the practice described here, including among children who do not fall into conventionally recognised high risk groups. Inner city dwellers and junior doctors are both highly mobile populations, adding to the risk that paediatricians, particularly those in training, may encounter tuberculosis with little or no previous experience of the condition.