Pesticide-contaminated feeds in integrated grass carp aquaculture: toxicology and bioaccumulation.

Effects of dissolved pesticides on fish are widely described, but little is known about effects of pesticide-contaminated feeds taken up orally by fish. In integrated farms, pesticides used on crops may affect grass carp that feed on plants from these fields. In northern Vietnam, grass carp suffer seasonal mass mortalities which may be caused by pesticide-contaminated plants. To test effects of pesticide-contaminated feeds on health and bioaccumulation in grass carp, a net-cage trial was conducted with 5 differently contaminated grasses. Grass was spiked with 2 levels of trichlorfon/fenitrothion and fenobucarb. Unspiked grass was used as a control. Fish were fed at a daily rate of 20% of body mass for 10 d. The concentrations of fenitrothion and fenobucarb in pond water increased over time. Effects on fish mortality were not found. Fenobucarb in feed showed the strongest effects on fish by lowering feed uptake, deforming the liver, increasing blood glucose and reducing cholinesterase activity in blood serum, depending on feed uptake. Fenobucarb showed increased levels in flesh in all treatments, suggesting bio-concentration. Trichlorfon and fenitrothion did not significantly affect feed uptake but showed concentration-dependent reduction of cholinesterase activity and liver changes. Fenitrothion showed bioaccumulation in flesh which was dependant on feed uptake, whereas trichlorfon was only detected in very low concentrations in all treatments. Pesticide levels were all detected below the maximum residue levels in food. The pesticide-contaminated feeds tested did not cause mortality in grass carp but were associated with negative physiological responses and may increase susceptibility to diseases.

The effects of chlorhexidine digluconate on human fibroblasts in vitro.

The drug chlorhexidine has been widely utilized as a wound antiseptic and oral antimicrobial rinse. There have been numerous reports on its safety as an oral rinse, but its effects on wound healing have been contradictory. The present study utilized human fibroblasts derived from skin and oral tissues to test the effects of chlorhexidine on viability, growth, collagen gel contractions, and total protein synthesis. Cells were exposed for an hour to 0.005% and 0.002% chlorhexidine and for 30 seconds to 0.12% chlorhexidine. Our results indicate that a 0.002% concentration of the drug shows minimal cytotoxicity, but is able to suppress cell division almost completely. Collagen gel contraction, as a model of wound contraction, was also severely affected by all of the concentrations of chlorhexidine used. Total protein synthesis was suppressed by chlorhexidine in collagen gel culture. The data support the hypothesis that chlorhexidine is highly cytotoxic to cells in vitro, but various cell functions such as proliferation, collagen gel contraction, and protein synthesis are affected to different degrees by the drug.

Results of limited initial periodontal therapy in smokers and non-smokers.

Eighty-seven adult patients (54 non-smokers and 33 smokers) with moderate to advanced periodontitis were treated with 1-hour full-mouth subgingival scaling and root planing, with no maintenance recalls, during this 9-month study. Clinical parameters assessed at target sites included probing depth, clinical attachment level, bleeding on probing, gingival index, and plaque index. Data were collected at baseline, and 3, 6, and 9 months. Baseline probing depth for non-smokers was 5.46 +/- .46 mm and for smokers 5.70 +/- 0.66 mm. Data analysis (t test) revealed that both non-smokers and smokers had a statistically significant decrease (P < 0.05) in probing depth at 3 months which was maintained throughout the study. At 9 months non-smokers maintained a mean decrease in probing depth of 0.60 mm and smokers a mean decrease of 0.65 mm. Both smokers and non-smokers displayed a significant gain (P < 0.05) in clinical attachment level after initial therapy when compared to baseline readings. At 9 months the mean gain in clinical attachment level for non-smokers was 0.47 mm and 0.59 mm for smokers. Plaque index scores remained consistent for smokers and non-smokers for the duration of the study. The gingival index at baseline was significantly (P < 0.05) lower in smokers (1.32 +/- 0.45) than non-smokers (1.45 +/- 0.40). By 9 months only the gingival index of non-smokers decreased significantly compared to baseline (1.26 +/- 0.37). Bleeding on probing was a prerequisite for target sites at baseline. At 9 months both smokers (0.67 +/- 0.39) and non-smokers (0.78 +/- 0.30) had a significant decrease in bleeding on probing compared to baseline. At 9 months there were no significant differences between smokers and non-smokers comparing probing depth, clinical attachment level, plaque index, bleeding on probing, and gingival index. The data have shown that smokers and non-smokers responded similarly after 9 months to the limited amount of initial therapy provided.

The intraosseous course of the mandibular incisive nerve in the mandibular symphysis.

The use of the mandibular symphysis as a source of autogenous bone grafting material has been well documented. Currently, no references in the literature describe the intraosseous distribution of the neurovascular complex anterior to the mental nerve with respect to its position buccolingually and apicocoronally. The objective of this study was to evaluate the distribution of the incisive nerve and measure its location buccolingually and apicocoronally in the anterior mandible and determine its possible significance to clinical practice. According to macroscopic dissection, the mandibular incisive nerve is a normal structure that typically extends closer to the midline than previously reported. To reduce postoperative neurovascular morbidity, this should be considered when using the mandibular symphysis as a source of autogenous bone or during placement of implants in the anterior mandible.

Clinical evaluation of a new flossing device.

The clinical effectiveness of a new flossing device, the Floss Plus easy flosser, in reducing interproximal plaque and interproximal gingival inflammation was compared to the effectiveness of hand-held floss. The first phase studied 36 dental students, while the second studied 26 adult patients undergoing supportive periodontal treatment. In both phases, the subjects were divided into two groups. One group used the flossing device, while the second group used hand-held floss. The Gingival Index and Plaque Index were taken at baseline, 1 week, and 6 weeks. All groups experienced a significant decrease in the amount of interproximal inflammation and plaque, regardless of which flossing method was used. There was no statistically significant difference between the two flossing methods in the reduction of interproximal inflammation or plaque. These results indicated that the Floss Plus easy flosser is as effective as hand-held floss in reducing interproximal plaque and gingivitis. The use of this aid may benefit those patients who lack the dexterity for hand-held floss or who find flossing cumbersome.

Clinical evaluation of an ionic toothbrush in the removal of established plaque and reduction of gingivitis.

The clinical effectiveness of a manual ionic toothbrush in the removal of dental plaque and the reduction of gingivitis was evaluated. A double-blind study evaluated the effect of a small, imperceptible electric current on established dental plaque and gingivitis during toothbrushing. Sixty-four adults completed the study. Gingivitis and plaque scores were determined at baseline and after 3 and 6 months. The baseline indices of the two groups were well balanced. At each examination, the participants were instructed how to hold the toothbrush properly and reminded to change brush heads every 4 weeks. Statistically significant improvements in Löe Gingival Index scores were observed from baseline to 6 months between the control and test groups and within the test group. The Quigley-Hein Plaque Index scores also showed a significant improvement from baseline to 6 months between the control and test groups and within the test group.

The effectiveness of an ionic toothbrush in the removal of dental plaque and reduction on gingivitis in orthodontic patients.

This investigation was undertaken to determine if an ionic toothbrush was effective at removing plaque and reducing gingivitis in patients wearing orthodontic appliances. Fifty-two orthodontic patients were randomly assigned to one of two groups and completed a six-week double-blind study. Group 1 consisted of the test group using the ionic toothbrush with an active battery; group 2 consisted of the control group using the ionic toothbrush with an inactive battery. The plaque and gingival indices were measured at baseline, two weeks, and six weeks. The findings demonstrated that the active ionic toothbrush was no more effective at plaque removal and gingivitis reduction than the inactive toothbrush. Although the active toothbrush did effectively remove plaque and reduce gingivitis over the course of six weeks, it showed no significant improvement over the same toothbrush that contained an inactive battery. It was observed that the ionic toothbrush effectively reduced plaque and gingivitis regardless of the presence or absence of an active battery. The clinical findings demonstrated that an active ionic toothbrush was no more effective in removing plaque and reducing gingivitis in patients with orthodontic appliances than an inactive ionic toothbrush.