A point mutation in the 5' splice site of the dystrophin gene first intron responsible for X-linked dilated cardiomyopathy

X-linked dilated cardiomyopathy (XLDC) is a familial heart disease presenting in young males as a rapidly progressive congestive heart failure, without clinical signs of skeletal myopathy. This condition has recently been linked to the dystrophin gene in some families and deletions encompassing the genomic region coding for the first muscle exon have been detected. In order to identify the defect responsible for this disease at the molecular level and to understand the reasons for the selective heart involvement, a family with a severe form of XLDC was studied. In the affected members, no deletions of the dystrophin gene were observed. Analysis of the muscle promoter, first exon and intron regions revealed the presence of a single point mutation at the first exon-intron boundary, inactivating the universally conserved 5' splice site consensus sequence of the first intron. This mutation introduced a new restriction site for MseI, which cosegregates with the disease in the analyzed family. Expression of the major dystrophin mRNA isoforms (from the muscle-, brain- and Purkinje cell-promoters) was completely abolished in the myocardium, while the brain- and Purkinje cell- (but not the muscle-) isoforms were detectable in the skeletal muscle. Immunocytochemical studies with anti- dystrophin antibodies showed that the protein was reduced in quantity but normally distributed in the skeletal muscle, while it was undetectable in the cardiac muscle. These findings indicate that expression of the muscle dystrophin isoform is critical for myocardial function and suggest that selective heart involvement in dystrophin- linked dilated cardiomyopathy is related to the absence, in the heart, of a compensatory expression of dystrophin from alternative promoters.      

Survivin gene promoter polymorphism -31G/C as a risk factor for keratocystic odontogenic tumor development

Several single nucleotide polymorphisms in survivin gene promoters, notably -31G/C, have been shown to modulate the expression and activity of the survivin protein. Consequently, the -31G/C polymorphism has been identified as a risk factor for the development of several types of tumors. The aim of this study was to investigate a possible association between the -31G/C polymorphism and the risk for keratocystic odontogenic tumor (KCOT) development. DNA from 52 biopsy specimens of KCOTs and from 82 buccal swabs of healthy individuals was subjected to PCR restriction fragment length polymorphism analysis to identify individual genotypes. The distribution of genotypes in KCOT and control groups, respectively, was: GG: 30 (57.7%) vs. 26 (31.7%); CG: 17 (32.7%) vs. 45 (54.9%); and CC: 5 (9.6%) vs. 11 (13.4%), respectively. These differences were statistically significant. The G allele was more common in the KCOT group than in the control group: 76 (74%) vs. 96 (59%), respectively. Logistic regression analysis showed that GC heterozygotes had a considerably decreased susceptibility for KCOTs compared with GG homozygotes. The same was true for GC+CC vs. GG. The GG genotype of the -31G/C polymorphism might be a risk factor for KCOT development.     

Presence of herpes simplex virus on the oral mucosa in patients undergoing chemotherapy

BACKGROUND: The aim of this study was to confirm the presence of herpes simplex virus type 1 and 2 on the oral mucosa, in patients undergoing chemotherapy, by means of polymerase chain reaction (PCR). METHODS: The research was carried out on 40 patients receiving chemotherapy as treatment for different malignancies. The status of oral mucosa and viral presence were assessed in all patients at the initial examination (prior to chemotherapy), and at the control examination (two weeks after the initiation of the chemotherapeutic cycle). RESULTS: The presence of HSV-1 was detected in 28 patients (70%) prior to chemotherapy, of whom 7 (25%) manifested oral complications. The control examination showed the presence of HSV-1 in 35 patients (87.5%), of whom 23 (65.7%) presented oral mucosa changes. HSV-2 has not been detected in any of the patients.     

Cytomorphometric and clinical investigation of the gingiva before and after low-level laser therapy of gingivitis in children

Gingival epithelial cells are the first physical barrier against periodontal pathogenic microorganisms. Bacterial products may penetrate the epithelium and directly disturb its integrity. We investigated the clinical and cytomorphological status of the gingiva in children with gingivitis before and after low-level laser therapy. The study enrolled 130 children divided into three groups: group 1 comprised 50 children with chronic catarrhal gingivitis who received basic treatment, group 2 comprised 50 children with chronic catarrhal gingivitis who received low-level laser treatment in addition to basic treatment, and group 3 comprised 30 children with healthy gingiva as controls. Oral hygiene and the status of the gingiva were assessed using the appropriate indexes before and after treatment. Inflammation of the gingiva was monitored by cytomorphometric evaluation. Cytomorphometric analysis revealed a statistically significant difference (p < 0.001) in the size of the nuclei of the stratified squamous epithelial cells of the gingiva before and after treatment in chronic catarrhal gingivitis. Evaluation using clinical parameters showed that treatment of gingivitis with basic treatment was successful. Cytomorphometric analysis showed that after basic treatment the nuclei of the stratified squamous epithelial cells of the gingiva were reduced in size, although not to the size found in healthy gingiva. However, after adjuvant low-level laser therapy, the size of the nuclei of the stratified squamous epithelial cells in the gingiva matched the size of the nuclei in the cells in healthy gingiva.     

Low frequency of NRAS and KRAS2 gene mutations in childhood myelodysplastic syndromes

In children, myelodysplastic syndromes (MDS) represent less then 10% of all hematological malignancies; consequently, molecular genetic studies dealing with this group of patients are scarce. We have analyzed 35 archival bone marrow samples of children with MDS for the presence of mutations in the first and second exons of the NRAS and KRAS2 genes. Mutations were detected with single-strand conformation polymorphism analysis in three patients. One patient harbored a mutation in the second exon of NRAS and two patients in the second exon of KRAS2. Sequencing was performed in two samples and novel mutations were found in both. One patient had a missense mutation in codon 45 of NRAS; the other had a silent mutation in codon 53 and a missense mutation in codon 55 of KRAS2.