[Clinical evaluation of the effectiveness of manual toothbrushes with different brush field characteristics].

Nowadays an individual selection of personal care depending on the dental and hygiene human status is of great importance. The present study examines the clinical efficacy of toothbrushes with different characteristics of the brush field. The cleaning efficiency of toothbrushes with horizontal slant bristle and smooth cutting of the brush field is 75%, toothbrushes with a horizontal slant bristle and multilevel cutting of the brush field - 79%, toothbrushes with power bulge - 70% and toothbrushes with a flat brush field - 56%.

[Microbiological study of the efficiency of various hygienic products for toothbrushes].

Options vary about the microbial contamination of toothbrushes as well as selection of adequate remedies for their disinfection. A microbiological study of contamination of toothbrushes was conducted considering the efficiency of purifying tablets, ultraviolet radiation and 0.05% solution of chlorhexidine as means of toothbrushes disinfection.

p53 promotes the fidelity of DNA end-joining activity by, in part, enhancing the expression of heterogeneous nuclear ribonucleoprotein G.

Many studies have suggested the involvement of wild-type (wt) p53 in the repair of DNA double-strand breaks (DSBs) via DNA end-joining (EJ) process. To investigate this possibility, we compared the capacity and fidelity of DNA EJ in RKO cells containing wt p53 and RKO cells containing no p53 (RKO cells with p53 knockdown). The p53 knockdown cells showed lower fidelity of DNA EJ compared to the control RKO cells.

Bmi-1 cooperates with human papillomavirus type 16 E6 to immortalize normal human oral keratinocytes.

Bmi-1 is a member of the polycomb group (PcG) transcription repressors and is implicated in human carcinogenesis. In normal human oral keratinocytes (NHOK), we found that exogenous Bmi-1 expression significantly extended the replicative life span without causing cellular immortalization. Immortalization of NHOK occurs only in combination with human papillomavirus type 16 E6 (HPV-16 E6) but not with E7.

Abnormal DNA end-joining activity in human head and neck cancer.

In human cells, DNA double-strand breaks (DSBs) are repaired primarily by the DNA end-joining (EJ) process and thus, abnormal DNA EJ activities lead to an accumulation of mutations and/or aneuploidy, resulting in genetic instability of cells. Since genetic instability is the hallmark of cancer cells, we studied the DNA EJ activities of normal, non-malignant immortalized and malignant human epithelial cells to investigate the association between DNA EJ and carcinogenesis. We found a significant diminution of precise (error-free) DNA EJ activities in non-malignant immortalized human oral keratinocytes (HOK-16B) and human head and neck squamous cell carcinoma (HNSCC) cells compared to that in normal human oral keratinocytes (NHOK).

HPV-16 E6 oncoprotein impairs the fidelity of DNA end-joining via p53-dependent and -independent pathways.

We previously reported that the E6 oncoprotein of high-risk human papillomavirus (HPV) caused genetic instability and oncogenesis by disrupting cellular DNA repair. Here, to investigate the effect of different domains of E6 on DNA double-strand break (DSB) repair, we infected normal human oral fibroblasts (NHOF) with retroviruses expressing wild-type (wt) or mutant (mt) HPV-16 E6 and examined the cellular DNA end-joining (EJ) activity. The cells expressing E6 showed not only a diminution of error-free DNA EJ but also an increase in erroneous DNA EJ capacity if compared with cells without wt E6.

[Laboratory control over warfarin therapy in patients with acute coronary syndrome].

Aim: To elicit the most sensitive and reliable method of control over administration of indirect anticoagulants.

Material And Methods: Sixty patients with acute coronary syndrome were studied. They received varfarin under the control of international normalized ratio (INR) calculated by the tables in cases of prothrombin time (PT) estimation on a stationary turbidynamic hemocoagulometer from venous and capillary blood by thromboplastins.

Senescence occurs with hTERT repression and limited telomere shortening in human oral keratinocytes cultured with feeder cells.

We investigated the phenotypic and molecular alterations in normal human oral keratinocytes (NHOK) during in vitro replication in two different culture conditions. The cells were cultured either in chemically defined Keratinocyte Growth Medium (KGM) without feeder layers or in serum-containing flavin-adenine dinucleotide (FAD) medium with feeder layers. Primary NHOK underwent 22 +/- 3 population doublings (PDs) in KGM and 42 +/- 4 PDs in FAD medium, reflecting 52% increase in replication capacity with feeder layers.

Introduction of human telomerase reverse transcriptase to normal human fibroblasts enhances DNA repair capacity.

Purpose: From numerous reports on proteins involved in DNA repair and telomere maintenance that physically associate with human telomerase reverse transcriptase (hTERT), we inferred that hTERT/telomerase might play a role in DNA repair. We investigated this possibility in normal human oral fibroblasts (NHOF) with and without ectopic expression of hTERT/telomerase.

Experimental Design: To study the effect of hTERT/telomerase on DNA repair, we examined the mutation frequency rate, host cell reactivation rate, nucleotide excision repair capacity, and DNA end-joining activity of NHOF and NHOF capable of expressing hTERT/telomerase (NHOF-T).

Telomere shortening does not occur during postmaturational aging in situ in normal human oral fibroblasts.

We investigated whether the telomere length, i.e. mean terminal restriction fragment (TRF) length, decreases during in situ aging in normal human oral fibroblasts (NHOF).

Senescence-associated genes in normal human oral keratinocytes.

The current study was undertaken to identify senescence-associated (SA) genes in cultured normal human oral keratinocytes (NHOK). Primary NHOK were serially subcultured in vitro as dispersed cells in low (0.15 mM) Ca(2+) medium until senescence.

The telomeric length and heterogeneity decrease with age in normal human oral keratinocytes.

We have examined the telomere length in NHOK explanted from 28 donors between the ages of 21 and 84 years. Genomic DNA was isolated from exponentially replicating NHOK and digested with HinFI to yield terminal restriction fragments (TRF). The TRF length ranged from 4.

The temperature sensitive mutant p53-143ala extends in vitro life span, promotes errors in DNA replication and impairs DNA repair in normal human oral keratinocytes.

Many human cancers contain a hemizygous point missense mutation in p53, allowing expression of both wild-type and mutant p53. To understand the relationship between wild-type and mutant p53 in cells, we investigated the influence of a naturally occurring temperature-sensitive mutant p53 (valine to alanine substitution at codon 143: mp53-143ala) on the life span of normal human oral keratinocytes (NHOK) and the expression of wild-type p53. We also investigated the effect of the mutant p53 on the genetic stability of NHOK.

Enhanced activity of cloned hamster TERT gene promoter in transformed cells.

In 7,12-dimethylbenz[a]anthracene-treated hamster pouch epithelial cells, telomerase activity increased within 1 week of treatment and reached a 6-7-fold increase within 3 weeks. To investigate this phenomenon, we have cloned and sequenced the hamster telomerase catalytic subunit (hamTERT) promoter. Transient transfection with different genomic segments upstream of the ATG translation initiation codon linked to the luciferase reporter gene mapped the core promoter within a 250 bp region.

In vitro replication and differentiation of normal human oral keratinocytes.

The replication kinetics and cytological changes of normal human oral keratinocytes (NHOK) isolated from the basal surface of oral epithelial sheet and cultured as dispersed cells in low (0.15 mM) Ca(2+) medium without serum were analyzed. Replicating NHOK were quantitated by cell count and identified by [(3)H]thymidine uptake.

The E7 oncoprotein of human papillomavirus type 16 interacts with F-actin in vitro and in vivo.

We report here that E7 oncoprotein of human papillomavirus type 16 (HPV-16) forms a complex in vivo and in vitro with actin, one of the components of the cellular cytoskeleton. The in vivo interaction was detected by immunofluorescent staining and confocal microscopic examination of normal human oral keratinocytes (NHOK) and CV-1 cells after transient expression of E7 employing the vaccinia virus-T7 RNA polymerase system and by coimmunoprecipitation from an immortalized, nontumorigenic cell line obtained after transfecting NHOK with the cloned HPV-16 DNA genome. The in vitro interaction was detected by cosedimentation of bacterially expressed E7 phosphorylated with rabbit reticulocyte lysate or purified casein kinase II (CKII) prior to incubation with F-actin.

Differential gene expression in neoplastic and human papillomavirus-immortalized oral keratinocytes.

We have previously demonstrated that normal human oral keratinocytes immortalized by transfection with human papillomavirus type-16 Dna became tumorigenic after exposure to a chemical carcinogen. In an effort to detect differentially regulated genes associated with this transition from the immortal to the malignant phenotype, we employed representational differences analysis (a PCR-coupled subtractive hybridization technique). After analysing 50 colonies, 12 putative messages were identified.

Ethanol upregulates the expression of p21 WAF1/CIP1 and prolongs G1 transition via a p53-independent pathway in human epithelial cells.

The control of cell cycle progression is necessary for accuracy in the replication of DNA and the distribution of genetic information to daughter cells. Disturbances in progression of the cell cycle may result in the loss of genomic integrity, a 'hallmark' of cancer cells. Extensive consumption of alcoholic beverages is a risk factor associated with the development of various human epidermoid cancer including oral and pharyngeal squamous cell carcinomas.

HPV-16 oncogenes E6 and E7 are mutagenic in normal human oral keratinocytes.

The mutation frequency of pS189 shuttle vector plasmids is higher in human oral keratinocytes (NHOK) immortalized with cloned human papillomavirus-16 (HPV-16) genome than in primary normal NHOK (NHOK). To determine whether oncoproteins E6 and E7 of HPV-16 are responsible for the higher mutation frequency of the plasmids, we measured the mutation frequency in NHOK and in NHOK expressing the HPV-16 oncogenes (E6, E7, or E6 plus E7). We also measured the mutation frequency in NHOK expressing the E6 or E7 proteins of the non-oncogenic HPV-6b.

Actual versus self-reported cognitive dysfunction in HIV-1 infection: memory-metamemory dissociations.

The relationship between subjective awareness and objective neuropsychological status in HIV-1 infection remains unclear. Forty-six HIV-1 seropositive males were administered a battery of neuropsychological measures assessing episodic memory, metacognition, and depression. Results of ANOVA revealed a dissociation between subjects' self-complaint of neuropsychological impairment and objective performance, with subjects who denied cognitive impairment performing worse on memory testing.

Distribution of alternatively spliced chicken c-myb exon 9A among hematopoietic tissues.

The role of the c-myb proto-oncogene in cellular differentiation may be regulated in part by alternative splicing of its mRNAs. Previously, two forms of alternative splicing of the chicken c-myb gene between exons 9 and 10 were described: one form utilizes the entire 360 base pair (bp) exon 9A while a second form utilizes exon 9A' which consists of the 3' 150 bp of exon 9A. In this study the distribution among chicken hematopoietic tissues of these two forms of alternative splicing was determined by Northern blot analysis using a probe specific for exon 9A.

Alternative splicing of the chicken c-myb exon 9A.

The c-myb gene products are thought to be regulators of cellular replication and of differentiation and heterogeneity may underlie their multiple functions. To investigate the possible existence of heterogeneity we have examined the chicken c-myb mRNAs by Northern blot analysis and polymerase chain reaction amplification of cDNAs (RT-PCR). Northern blot analysis with the c-myb cDNA clone pSG3, which contains the entire open reading frame (ORF) plus 500 base pairs of 3' untranslated sequences (Gerondakis & Bishop, 1986), and genomic probes revealed c-myb RNA species of 4.