Vitronectin-Derived Peptide Promotes Reparative Dentin Formation

Exposed dental pulp can maintain its vitality through a pulp-capping procedure with biocompatible materials, followed by reparative dentin formation. Our previous study demonstrated that a vitronectin-derived peptide (VnP-16) promotes osteoblast differentiation and concomitantly restrains osteoclast differentiation and resorptive function. In this study, we aimed to demonstrate that VnP-16 promotes odontoblast differentiation, mineralization, and reparative dentin formation in a pulp exposure model using a rat tooth. VnP-16 showed no cytotoxicity and promoted cellular behavior in human dental pulp cells, enhancing their differentiation into odontoblast-like cells and mineralization, effects that are comparable to those obtained with vitronectin. In a rat pulp exposure model, VnP-16 showed mild inflammatory responses at 2 and 4 wk or none. Mineral trioxide aggregate (MTA) demonstrated a tendency of early formation of reparative dentin at 2 wk when compared with recombinant human bone morphogenetic protein 2 (rhBMP-2) and VnP-16. However, VnP-16 induced reparative dentin formation similar to MTA and rhBMP-2 without inflammation at 4 wk. In addition, VnP-16 showed a thicker and homogeneous reparative dentin formation versus MTA and rhBMP-2. Collectively, these results suggest that VnP-16 can be a useful, direct pulp-capping agent for highly qualified reparative dentin formation by promoting cell behavior and odontoblastic differentiation of human dental pulp cells.

A randomized comparison of prism adaptation and augmented surgery in the surgical management of esotropia associated with hypermetropia: one-year surgical outcomes

OBJECTIVE

To compare motor and sensory 1-year surgical outcomes in patients with hypermetropic esotropia, managed with either augmented surgery based on the average of the near deviation with and without correction or preoperative prism adaptation.

METHODS

Forty-three patients with hypermetropic esotropia without distance-near disparity entered a randomized prospective evaluation of augmented surgery (group A, 27 patients) versus prism adaptation (group P, 16 patients). The formula for augmenting the amount of the rectus muscle recession was based on the average of the near deviation with and without correction in group A and the prism-adapted angle of deviation in group P. During prism adaptation, 9 of 16 patients in group P responded to prism. Motor and sensory outcomes of the Worth 4-dot test at 6 and 0.33 m and the Titmus stereotest were evaluated 1, 3, 6, and 12 months after surgery.

RESULTS

Postoperative deviations of 8 PD or less at distance were achieved in 24 of 27 patients (89%) of group A and in 7 of the remaining 8 patients (88%) of prism responders and in all 7 prism nonresponders (100%) in group P. No significant difference existed between groups A and P, as well as between the prism responders and prism nonresponders in group P in terms of near and distance deviation 1 year after surgery. The sensory outcomes improved over time in group A and prism responders.

CONCLUSION

There were no significant differences in the surgical outcomes between each group. However, the small sample size may limit the power to detect any statistically significant differences.

Concurrence of replicative senescence and elevated expression of p16(INK4A) with subculture-induced but not calcium-induced differentiation in normal human oral keratinocytes

Primary normal human oral keratinocytes (NHOKs) undergo differentiation in the presence of calcium concentrations higher than 0.15 mM in vitro, which is useful in investigating the mechanisms involved in the differentiation of epithelial cells. Serial subculture of NHOKs to the postmitotic stage also induces terminal differentiation. However, the detailed mechanisms of both differentiation processes remain substantially unknown. To investigate the molecular differences in these processes, NHOKs were induced to differentiate by exposure to 1.2 mM of calcium and by serial subculture to the postmitotic stage. To study whether the cells were induced to differentiate and to undergo replicative senescence, the amount of cellular involucrin and the expression of senescence-associated beta-galactosidase (SA-beta-gal) were measured respectively. The expression of replicative senescence-associated genes and the activity of telomerase from the differentiated cells were also determined. Both calcium treatment and serial subculture to the postmitotic stage notably elevated the cellular involucrin. The percentage of SA-beta-gal-positive cells was significantly elevated by the continued subculture, but such changes were not observed in keratinocytes exposed to calcium. The concentration of cellular p16(INK4A) protein was progressively increased by the continued subculture but was not changed by calcium treatment. On the other hand, the concentrations of cellular p53 were similar in both differentiation processes. However, telomerase activity was lost in NHOKs that had undergone differentiation by both calcium treatment and serial subculture. The results indicate that calcium-induced differentiation of NHOKs has similar characteristics to their serial subculture-induced differentiation, but that the differentiation processes are not identical, because calcium-induced differentiation does not concur with either replicative senescence or the gradually increased concentration of p16(INK4A).

A comparison of Min's glasses and conventional occlusion therapy in the treatment of amblyopic children: a prospective study

Min's glasses are specially manufactured in order to enhance the satisfaction of the wearer and increase treatment effectiveness. We compared the effectiveness of Min's glasses with that of conventional occlusion therapy in amblyopic pediatric patients. We prospectively studied 60 amblyopic patients. For four to 30 months, 24 of the patients were treated with conventional patch occlusion (patch group) and 36 of them were treated with Min's glasses (glasses group). We compared the improvement in visual acuity and the treatment compliance between both groups, according to age (over six and less than six), sex, type of amblyopia, and the duration of treatment. Sixteen patients (66.7%) in the patch group and 32 patients (88.9%) in glasses group showed improvement in visual acuity (p = 0.002). The pre-treatment average log MAR acuity was 0.56 +/- 0.25 in the patch group, and 0.59 +/- 0.25 in the glasses group. The average improvement in visual acuity was a 0.17 log MAR score in the patch group, and a 0.31 log MAR score in the glasses group (p = 0.004). Compliance was 59.54% in the patch group and 83.44% in the glasses group (p = 0.012). The pre-treatment average log MAR acuity was 0.49 +/- 0.23 for children over six years of age in the patch group, and 0.58 +/- 0.28 for children over six years of age in the glasses group. For children over six years of age in the glasses group the improvement in visual acuity (0.29 log MAR score) was greater than for children over six years of age in the patch group (0.06 log MAR score) (p = 0.0003). The pre-treatment average log MAR acuity was 0.55 +/- 0.22 for female patients in the patch group, and 0.60 +/- 0.25 for female patients in the glasses group. Female patients in the glasses group also showed a greater visual acuity improvement (0.29 log MAR score) than female patients in the patch group (0.14 log MAR score) (p = 0.0028). However, there were no differences between the groups in patients less than six years of age and in male patients. In conclusion, Min's glasses were more effective than conventional treatment with a patch in improving visual acuity and encouraging compliance in pediatric amblyopic patients, especially in children over six years of age and in girls.

Retinoic acid extends the in vitro life span of normal human oral keratinocytes by decreasing p16(INK4A) expression and maintaining telomerase activity

Retinoic acid (RA) plays an important role in the regulation of cell growth and differentiation. To investigate whether RA extends in vitro the life span of human epithelial cells, we examined the effect of all-trans RA on both the cumulative population-doubling level (PDL) and the replicative senescence of cultured oral keratinocytes. When proliferating oral keratinocytes were cultured in medium containing 1 nM of all-trans RA, the in vitro life span of the cells was increased 1.5- to 1.8-fold compared to the vehicle control and the replicative senescence of the cells was significantly inhibited. Since the replicative senescence of human epithelial cells is associated with a steady increase of p16(INK4A) and a loss of telomerase activity, we expected that RA could delay the replicative senescence of oral keratinocytes by decreasing p16(INK4A) expression and/or inhibiting the loss of telomerase activity. To test this possibility, we examined the expression of replicative senescence-associated genes and the telomerase activities of different PDL numbers of oral keratinocytes exposed to 1 nM of all-trans RA. The protein level of cellular p16(INK4A) in the RA-treated oral keratinocytes was gradually but significantly enhanced by an increased PDL number; however, the level was significantly lower than that of the vehicle control at all of the same PDL numbers. In contrast, the telomerase activity was maintained in oral keratinocytes with increasing PDL numbers induced by RA treatment. Summarizing, these results indicate that RA induces the in vitro life-span extension of oral keratinocytes, which is linked to a decreased cellular level of p16(INK4A) and the maintenance of telomerase activity.

Staphylococcus lugdunensis--a potential pathogen in oral infection

OBJECTIVE

The purpose of this study was to investigate the pathogenicity of Staphylococcus lugdunensis in acute oral infection.

STUDY DESIGN

S. lugdunensis was isolated from patients with acute oral infections and from healthy control subjects. Antibiotic susceptibility, in vitro cellular toxicity, in vivo virulence, and hemolytic activity testing and dot blot analysis were performed. The statistical significance of in vitro cellular toxicity was determined by means of analysis of variance.

RESULTS

Isolated from the infected patients, S. lugdunensis showed resistance to penicillin, ampicillin, methicillin, cephalothin, and clindamycin, exhibited virulence in vivo, and showed delta-like hemolysin activity. Four of the 6 strains of S. lugdunensis gave synergistic hemolysis. In dot blot analysis, S. lugdunensis showed a positive reaction to the probe of the delta-hemolysin gene in S. aureus.

CONCLUSIONS

The results suggest that S. lugdunensis may be a potential pathogen in acute oral infection.

A randomized comparison of prism adaptation and augmented surgery in the surgical management of esotropia associated with hypermetropia

OBJECTIVE

To compare both motor and sensory surgical outcomes for patients with esotropia associated with hypermetropia managed with an augmented surgery based on the average of the near deviation with and without correction vs preoperative prism adaptation.

METHODS

Forty-three patients with esotropia associated with hypermetropia entered a randomized prospective evaluation of augmented surgery (group A, 27 patients) versus prism adaptation (group P, 16 patients). The formula for augmenting the amount of the rectus muscle recession was based on the average of the near deviation with and without correction in group A, and the prism-adapted angle of deviation in group P.

RESULTS

In group A, postoperative deviations of 8 prism diopters (delta) or less at distance and at near were achieved in 24 patients (88%), and in 22 patients (81%), respectively. In nine prism responder patients, postoperative deviations of 8 delta or less at distance and at near were achieved in eight patients (89%). In seven nonresponder patients, postoperative deviations of 8 delta or less at distance and at near were achieved in six patients (86%). No significant difference between the two groups in terms of near and distance deviation at 1 and 3 months postoperatively were noted.

CONCLUSION

No significant difference existed in the motor outcomes between the two groups, or between the prism responder and prism nonresponder groups. Further detailed studies must be made in a large number of patients.

Terminal differentiation of normal human oral keratinocytes is associated with enhanced cellular TGF-beta and phospholipase C-gamma 1 levels and apoptotic cell death

Subculture of primary normal human oral keratinocytes (NHOK) results in terminal differentiation, leading to cell death. To investigate whether the subculture-induced death of NHOK is due to apoptosis, we studied transferase-mediated dUTP nick end labeling (TUNEL)-positive cells, DNA fragmentation, and expression of several apoptosis-associated genes from NHOK with different passage numbers. We also determined the effect of transforming growth factor beta1 (TGF-beta1) on the induction of apoptosis in NHOK. We were able to subculture primary NHOK up to the fifth passage, at which point cells showed morphological features of differentiation. Appearance of DNA fragmentation concurrently occurred with an increase in the number of TUNEL-positive cells with higher passage numbers. The level of cellular p53 proteins was gradually decreased by the continued passage of cells, whereas the levels of intracellular and secreted TGF-beta and phospholipase C-gamma1 (PLC-gamma1) were significantly elevated by serial subculture. Exogenous TGF-beta1 also induced differentiation and apoptosis of proliferating NHOK. These data indicate that terminal differentiation of NHOK is associated with apoptosis, which is, in part, linked to elevated cellular levels of TGF-beta and PLC-gamma1.

Comparison of inferior oblique muscle weakening by anterior transposition or myectomy: a prospective study of 20 cases

BACKGROUND/AIMS

Among the various weakening techniques of inferior oblique muscle overaction, the most commonly used techniques include myectomy, recession, and anterior transposition. Anterior transposition and myectomy were compared to evaluate the surgical results in inferior oblique overaction.

METHODS

20 children with bilateral +3 overacting inferior oblique muscles underwent a prospective randomised study by which the anterior transposition procedure in one eye was compared with the myectomy procedure in the other eye.

RESULTS

Postoperative follow up averaged 2 years. The success rates in two surgical procedures were 85% for the anterior transposition and 25% for the myectomy (standard of success was based on zero inferior oblique overaction). In only one case did the anterior transposition tend to limit the elevation of the eye in the midline, adduction, and abduction. Anterior transposition produced hypotropia at the primary position in only one case. Most eyes that underwent myectomy (75%) showed apparent residual overaction.

CONCLUSION

The anterior transposition appeared to be more effective in eliminating the overaction of inferior oblique muscle than the myectomy.

Activity of human papillomavirus type 16 P97 promoter in immortal and tumorigenic human oral keratinocytes

We previously immortalized normal human oral keratinocytes (NHOK) by transfection with cloned human papillomavirus type 16 (HPV-16) genome and converted these immortalized cells to tumorigenic cells with chemical carcinogens. Since the tumorigenic cells expressed higher level of HPV-16 E6/E7 transcripts, we predicted that enhanced E6/E7 expression was induced by mutations at the long control region (LCR) of the viral genome integrated into cellular chromosome. To test this possibility, we sequenced the entire HPV-16 LCR from immortalized and tumorigenic cells, but no difference in the sequences in all of the tested cells was observed. However, it is possible that such differences in the expression of E6/E7 could have originated from different activities of cellular transcription factors in the different cells. To examine this prospect, we subcloned entire LCR into a reporter gene and determined the promoter activity of LCR in immortalized and tumorigenic cells. We found that the LCR promoter activity was significantly higher in tumorigenic cells when comparing to immortalized cells. We also observed that at least 477 nucleotides upstream of E6 open reading frame are needed for the maximum LCR promoter activity in tumorigenic cells.

Conversion of normal human oral keratinocytes to tumorigenic cells is associated with the acquisition of resistance to TGF-beta

Normal human epithelial cells cannot proliferate and undergo apoptosis in the presence of transforming growth factor-beta (TGF-beta) in vitro, but many human epidermoid cancer cells are resistant to TGF-beta. Resistance to TGF-beta may thus, in part, be responsible for uncontrolled proliferation of cancer cells. Though detailed mechanisms for the resistance of cancer cells to TGF-beta remain unknown, resistance may be due to decreased expression of TGF-beta receptors from cancer cells. To investigate this possibility, we determined the expression of TGF-beta and type II TGF-beta receptor in primary normal human oral keratinocytes (NHOK), human papillomavirus-immortalized human oral keratinocytes (HOK-16B) and two tumor cell lines derived from HOK-16B (CTHOK-16B-BaP and CTHOK-16B-DMBA). Our results show that (1) the cellular and secretory TGF-beta levels in immortalized and tumor cells were notably lower than in NHOK and (2) the level of type II TGF-beta receptor of the tested cells was similar to each other. Taken together, the conversion of NHOK to tumorigenic cells may, in part, be due to the acquisition of NHOK resistance to TGF-beta through underexpression of this cytokine.

A muscle-clamping system with an absorbable jaw clip to reduce suturing in strabismus surgery

Most of the ocular complications of strabismus surgery are related to needle trauma during the suturing of muscles. The authors have developed a muscle-clamping system with an absorbable jaw clip to facilitate exact techniques of eye muscle surgery and to reduce the risk of complications. The absorbable jaw clip is composed of a lower fixing body with three jaws and an upper supporting body. The clip is used to tie an extraocular muscle (which is moved and reattached with the membrane) with a single scleral bite. Using the absorbable jaw clip, the authors performed superior rectus recession on 16 eyes of eight rabbits. The authors examined the conjunctival injection, muscle adhesion power, and light microscopic findings at 1, 2, 4, and 8 weeks postoperatively. The conjunctival injection diminished with time. Bond strengths ranged from 380 to 620 gram gravity, which is sufficient to withstand the normal pull of human extraocular muscles. Some inflammatory cells were found microscopically, and fibrosis increased with time. The muscle-clamping method with the newly invented clip was technically easy, fast, and exact, and it may reduce suturing and complications during strabismus surgery.

Combined oral carcinogenicity of HPV-16 and benzo(a)pyrene: an in vitro multistep carcinogenesis model

We previously immortalized normal human oral keratinocytes by transfection with recombinant HPV-16 DNA and subsequently exposed the cells to benzo(a)pyrene for 7 days. The exposure to benzo(a)pyrene modified the immortalized cells: the modified cells (HOK-16B-BaP) proliferated in an ordinary culture medium containing physiological calcium level (1.5 mM), but demonstrated only enhanced proliferation capacity without tumor formation in nude mice and failed to show in vitro anchorage-independency. In this study, we further modified the HOK-16B-BaP cells by subculturing the cells in a medium containing benzo(a)pyrene for 6 months. The cells were further modified with a chronic benzo(a)pyrene exposure and were termed HOK-16B-BaP-T cells (1) demonstrated a malignant phenotype in organotypic 'raft' culture, (2) showed in vitro anchorage-independency, (3) developed tumors in nude mice when injected subcutaneously, (4) contained a significantly higher copy number of intact and integrated HPV-16 DNA; (5) contained higher level of HPV-16 E6/E7 messages and E7 protein, (6) were more resistant to transforming growth factor-beta 1 and (7) secreted higher level of vascular endothelial growth factor with molecular weight of 56 kd than parental HOK-16B-BaP cells. However, the levels of p53 and ras proteins and the levels of p53, c-myc and c-fos transcripts in the HOK-16B-BaP-T cells were not different from those in the HOK-16B-BaP cells. The highly conserved coding regions of the p53, c-Ha-ras1, and c-Ki-ras2 genes of the tumor cells were not mutated. These data indicate that the HPV-immortalized human oral keratinocytes can convert to tumorigenic cells by chronic exposure to benzo(a)pyrene. The tumorigenic conversion seems to be associated with (1) the overexpression of viral oncogenes such as E6 and E7 genes, (2) the higher resistance of cells to transforming growth factor-beta 1 and (3) the high secretion of 56 kd vascular endothelial growth factor from the cells.

Inactivation of the p53 gene by either mutation or HPV infection is extremely frequent in human oral squamous cell carcinoma cell lines

The state of p53 tumour suppressor and the frequency of high-risk human papillomavirus (HPV) infections were studied in nine human oral cancer cell lines. Three cancer cell lines (SCC-4, Tu-177 and FaDu) had similar amounts of p53 transcripts to normal cells, but contained significantly higher levels of p53 protein than the normal control cells. Sequencing highly conserved open reading frames of the p53 gene of these cancer cells showed point mutations in the SCC-4 and Tu-177 cell lines, a base transition from CCC to TCC occurred at codon 151; and in the line FaDu, a mutation of CGG to CTG occurred at codon 248. The HEp-2 and 1483 cancer lines contained significantly lower levels of p53 protein compared to the normal counterpart. Sequencing of p53 cDNA for HEp-2 and 1483 lines showed no mutations, but northern analysis revealed that these cell lines expressed HPV-18 E6/E7 messages. Four cell lines (SCC-9, SCC-15, SCC-25, and Tu-139) expressed negligible amounts of p53 transcripts compared to the normal counterpart and undetectable levels of p53 protein. These cell lines contained mutations in the highly conserved open reading frames of the p53 gene as follows: the SCC-9 had a deletion of 32 base pairs between codons 274 and 285; the line SCC-15 had an insertion of five base pairs between codons 224 and 225; the line SCC-25 had a deletion of two base pairs in codon 209; and the Tu-139 line had a deletion of 46 base pairs between codons 171 and 186.(ABSTRACT TRUNCATED AT 250 WORDS)

Combined effects of human papillomavirus-18 and N-methyl-N'-nitro-N-nitrosoguanidine on the transformation of normal human oral keratinocytes

We immortalized oral keratinocytes by transfecting them with recombinant human papillomavirus (HPV) type 18 DNA and established three cell lines. These lines were morphologically different from their normal counterpart, contained integrated entire HPV-18 DNA, and expressed the viral E6/E7 genes. The cells contained less p53 protein and more c-myc mRNA than normal cells. However, they proliferated only in keratinocyte growth medium (KGM) containing low calcium and were not tumorigenic in nude mice. To test the hypothesis that tumors result from the combined effect of a "high-risk" HPV and chemical carcinogens in the human oral cavity, we exposed the immortalized cells to the chemical carcinogen N-methyl-N'-nitro-N-nitrosoguanidine. Three chemically transformed cell colonies were isolated. These cells (a) proliferated well in both KGM and Dulbecco's modified minimum essential medium containing physiological levels of calcium; (b) were capable of proliferating in nude mice; (c) contained intact, integrated HPV-18 sequences; (d) transcribed substantially more HPV-18 E6/E7, transforming growth factor-alpha, and c-myc than the immortalized counterpart; and (e) contained, like the immortalized counterpart, less wild-type p53 protein and DCC message. These data indicate that human oral keratinocytes can be transformed by sequential exposure of normal keratinocytes to a "high-risk" HPV and chemical carcinogens.

Comparison of superior oblique tendon expander to superior oblique tenotomy for the management of superior oblique overaction and Brown syndrome

We compared surgical results of superior oblique tenotomy to the superior oblique silicone expander for the treatment of superior oblique overaction and Brown syndrome. Of 24 patients with bilateral superior oblique overaction, 13 underwent tenotomy and 11 had the silicone expander procedure. Reduction of A-pattern to within 10 prism diopters was achieved in 12/13 (92.3%) tenotomy patients and in 10/11 (90.9%) patients undergoing silicone expander (P greater than .05). Correction of superior oblique overaction on versions to within +/- 1 dysfunction was achieved in 22/26 (84.6%) of the tenotomies, and 21/22 (95.5%) silicone expander procedures (P greater than .05). Zero superior oblique dysfunction was found after 14/26 (53.8%) tenotomy procedures versus 18/22 (81.8%) silicone expander operations (P = .041). Superior oblique paresis occurred postoperatively in 4/13 (30.8%) tenotomy patients, whereas none of the 11 patients in the silicone expander group had superior oblique paresis (P = .044). Six patients who underwent superior oblique tenotomy for superior oblique overaction had preoperative stereopsis; following surgery, only two maintained the same level of stereopsis, and three patients totally lost all stereo acuity. All patients in the silicone expander group either maintained or had improved stereo acuity postoperatively. Seven patients with true Brown syndrome were operated on: three underwent the silicone expander procedure and four had a superior oblique tenotomy with an ipsilateral inferior oblique recession. The combination of superior oblique tenotomy with simultaneous ipsilateral inferior oblique recession resulted in an undercorrection in two of the four patients, whereas all three patients in the silicone expander group showed excellent ocular motility postoperatively, with two having normal versions and one a -1 residual limitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Immortalization of normal human oral keratinocytes with type 16 human papillomavirus

Primary human oral keratinocytes were transformed by transfection with recombinant human papillomavirus type 16 (HPV-16) DNA, and two transformed cell lines named human oral keratinocytes-16A and -16B (HOK-16A and HOK-16B) were established. While normal cells and cells transfected with vector only exhibited a limited lifespan, the HOK-16A and HOK-16B lines demonstrated immortality and altered morphology from their normal counterpart. The HOK-16A and HOK-16B lines contained approximately 40 and approximately 25 copies of intact HPV-16 DNA as integrated form per cell respectively, and both cell lines expressed several viral specific poly(A+) RNAs. Notably these cell lines also overexpressed cellular myc proto-oncogene in comparison with the normal counterpart. However, the immortalized cell lines were not able to produce tumors in nude mice, indicating that the cells are partially transformed. The HOK-16A and HOK-16B lines are, therefore, useful for investigating the multistep molecular events of oral carcinogenesis.

Effect of a modified rectus tuck on anterior ciliary artery perfusion

Strabismus surgery results in the permanent interruption of anterior ciliary blood flow, predisposing the eye to anterior segment ischemia (ASI). A primate model was used to assess the effectiveness of a new muscle-scleral tuck for preserving anterior ciliary artery circulation. The model consisted of removing 3 rectus muscles from both eyes of 2 rhesus monkeys, then performing a tuck on the inferior rectus (IR) right eye while leaving the left IR as a control. Four weeks later, a modified tuck was performed on the virgin left IR. Fluorescein iris angiograms of both eyes were obtained, and preoperative angiograms at 5-15 sec. showed normal 360 degrees perfusion. Postoperative follow-up angiograms showed segmental superior temporal filling defects and preservation of perfusion in the distribution of the IR. Comparison of fellow eyes tucked vs control IR showed no difference in the filling pattern in both monkeys. Comparison of the same eye before and after tuck also showed essentially the same filling pattern in all 4 eyes with preservation of inferior circulation. Our conclusion is that the modified tuck preserves the anterior ciliary blood flow and may be useful as a muscle-strengthening procedure in patients predisposed to developing ASI.

Combined synergistic antiherpetic effect of acyclovir and chlorhexidine in vitro

The combined effect of acyclovir and chlorhexidine on the replication and DNA synthesis of herpes simplex virus was studied. Acyclovir and chlorhexidine showed synergism in the inhibition of the viral replication by enhancing in part the reduction of viral DNA synthesis. These data indicate that combined therapy with acyclovir and chlorhexidine might be beneficial for the control of intraoral herpetic infections.

Three cell lines from hamster buccal pouch tumors induced by topical 7,12-dimethylbenz(a)anthracene, alone or in conjunction with herpes simplex virus inoculation

Three squamous carcinoma cell lines HBPC-1, HBPC-2, and HBPC-3 were established from hamster buccal pouch tumors induced by topical 7,12-dimethylbenz(a)anthracene (DMBA) treatment alone, topical DMBA treatment in conjunction with type 1 herpes simplex virus (HSV-1) inoculation, and topical DMBA application in combination with type 2 HSV (HSV-2) inoculation, respectively. The cells were epithelial in morphology, had a doubling time of approximately 18 h, and required bovine serum for optimal growth. They demonstrated an in vitro anchorage-independent growth and produced squamous cell carcinomas when transplanted into normal hamster pouch submucosa. The carcinoma cell lines equally expressed cellular hst, src, abl, and raf proto-oncogenes that were not expressed in the normal hamster pouch epithelial cells. An equal amount of fos gene expression was noticed in the normal pouch epithelial cells, HBPC-1 and HBPC-3, but the HBPC-2 expressed less fos poly(A+)RNA than the other cell lines. The myc proto-oncogene was also expressed both in the normal pouch epithelial cells and in the cancer cell lines. However, the size and number of expressed myc poly(A+)RNA in the normal cells and cancer cell lines differed. Although the normal cells and HBPC-1 expressed a single myc transcript, 1.7-kilobase (kb) and 2.3-kb, respectively, both HBPC-2 and HBPC-3 expressed two myc poly(A+)RNAs, 1.7-kb and 2.3-kb.

Active HSV-1 immunization prevents the cocarcinogenic activity of HSV-1 in the oral cavity of hamsters

Previous investigations have demonstrated that herpes simplex virus (HSV) increased the oral carcinogenic activity of 7,12-dimethylbenz[a]anthracene (DMBA) probably by enhancing the DMBA-induced amplification and overexpression of c-erb-B-1 proto-oncogene in hamster buccal pouch epithelium. The present study investigated the effect of active type 1 HSV (HSV-1) immunization on the development of oral cancer induced by HSV-1 and DMBA, alone or in combination, in the hamster buccal pouch. The results were similar to our previous report in that HSV-1 significantly enhanced the oncogenic effect of DMBA, and the numbers of pouches harboring tumor nodules and the numbers and sizes of tumors developed by topical DMBA were significantly increased by HSV-1 inoculation to the site of the DMBA application. Although HSV-1 immunization did not alter the carcinogenic activity of DMBA in animals receiving topical DMBA in combination with mock inoculation, it prevented the cocarcinogenic effect of HSV-1 in animals receiving topical DMBA in conjunction with HSV-1 inoculation. These data indicate that active HSV-1 immunization completely obstructs the co-oncogenic effect of HSV-1 in the oral cavity of hamsters.