A mathematical model of exposure of non-target Lepidoptera to Bt-maize pollen expressing Cry1Ab within Europe.

Genetically modified (GM) maize MON810 expresses a Cry1Ab insecticidal protein, derived from Bacillus thuringiensis (Bt), toxic to lepidopteran target pests such as Ostrinia nubilalis. An environmental risk to non-target Lepidoptera from this GM crop is exposure to harmful amounts of Bt-containing pollen deposited on host plants in or near MON810 fields. An 11-parameter mathematical model analysed exposure of larvae of three non-target species: the butterflies Inachis io (L.), Vanessa atalanta (L.) and moth Plutella xylostella (L.), in 11 representative maize cultivation regions in four European countries. A mortality-dose relationship was integrated with a dose-distance relationship to estimate mortality both within the maize MON810 crop and within the field margin at varying distances from the crop edge. Mortality estimates were adjusted to allow for physical effects; the lack of temporal coincidence between the susceptible larval stage concerned and the period over which maize MON810 pollen is shed; and seven further parameters concerned with maize agronomy and host-plant ecology. Sublethal effects were estimated and allowance made for aggregated pollen deposition. Estimated environmental impact was low: in all regions, the calculated mortality rate for worst-case scenarios was less than one individual in every 1572 for the butterflies and one in 392 for the moth.

A model of pollen-mediated gene flow for oilseed rape.

The development of genetically modified (GM) crops has precipitated the need for risk assessment and regulation of pollen-mediated gene flow. In response to this need we present a mathematical model to predict the spatial distribution of outcrossing between progenitor populations of oilseed rape. The model combines the processes of pollen dispersal and pollination, resulting from wind and insect activity. It includes the effects of post-pollination reproductive processes by relating the number of progeny to both pollen deposition and competition at the stigma. Predictions compare well with a range of experimental results for different-sized GM source crops (i.e. 0.0064-0.8 ha) and non-GM target crops with different fertilities (i.e. self-fertile to 80% male-sterile). For these comparisons, we represent the variation caused by wind and insect exposure as a constrained set of random functions and limit the range of insect transport to typical plant-scale distances. In addition, the model is used to examine the relative sensitivity to the factors that determine gene flow. Target-crop fertility and source-crop size are shown to be more important than other factors, including background pollen and the natural range of insect activity. The concept of isolation distance to regulate gene flow is most effective for self-fertile target crops, but is ineffective for male-sterile target crops with low background pollen.

Preparatory strategies in overlapping-task performance.

In four experiments, we tested whether perceptual identification is impeded by temporal overlap with another task. The results demonstrate that temporal overlap with an auditory task consistently impaired the identification of the highest digit in a briefly presented and masked array of digits. The impairment was especially pronounced when we emphasized speed on the auditory task, thus counteracting the normal tendency to focus advance preparation on the more challenging visual task. The data also indicate that previous findings of minimal effects of temporal overlap may have been due to the use of a restricted range of stimulus onset asynchronies. The present results demonstrate the important role of preparatory strategies in overlapping-task performance, and show that perceptual identification is impeded by the overlapping performance of another task.

Effect of antimicrobial mouth rinses on the incidence of localized alveolitis and infection following mandibular third molar oral surgery.

Mandibular third molars were removed from 400 patients who were divided into four different preoperative and postoperative rinsing groups using either normal saline solution, chloramine-T, povidone iodine, or sodium bicarbonate. The overall incidence of localized alveolitis and infection was 4.5% and 1.7%, respectfully. The incidence of the two postoperative problems proved not to be statistically significant when the four groups were compared with each other. There seems to be no apparent advantage to the preoperative and postoperative use of an antimicrobial mouth rinse in place of normal saline solution in reducing the incidence of either localized alveolitis or postoperative infections.

Tangier disease with oral abnormalities.

A patient with Tangier disease, pulpal calcifications, and bilateral mandibular intrabony lesions (unusual odontomas) is presented. A relationship between Tangier disease and the oral manifestations found in this patient has not been established. Of the 27 known patients with Tangier disease, only 2 have been examined.

Cardiovascular and respiratory response to intravenous diazepam, fentanyl, and methohexital in dental outpatients.

The cardiovascular and respiratory responses to a combination of diazepam and methohexital (D-M) were compared to those from a combination of diazepam, fentanyl, and methohexital (D-F-M). Both caused significant tachycardia after administration and during surgery. The D-F-M combination caused a significant decrease in both respiration rate and oxygen saturation. Surgeons preferred this combination for the production of sedation and cooperation of patients. Comparison of efficacy to toxicity suggests that the increase in patient cooperation for the D-F-M combination is at the expense of respiratory depression. The use of oxygen supplementation and monitoring of respiration is recommended during the use of the combination.

Recovery following intravenous sedation during dental surgery performed under local anesthesia.

Recovery of psychomotor and perceptual performance from two combinations of intravenous sedatives was assessed in 124 oral surgical patients undergoing third molar extractions under local infiltration anesthesia. Ninety-four patients in the experimental group received 15 mg of diazepam and 20 to 200 mg of methohexital intravenously on one occasion and 12.5 mg of diazepam, 20 to 200 mg of methohexital, and 0.1 mg of fentanyl intravenously on another occasion in a randomized, crossover design. Thirty patients in the control group received saline placebo intravenously during a single surgery. Both drug combinations produced significantly prolonged decrements in performance in comparison to placebo. Reduction in the diazepam dose from 15 to 12.5 mg and the addition of fentanyl, a short-acting narcotic, produced greater sedation without prolonging recovery. Psychomotor function recovered to preoperative levels before perceptual performance. These results show that postsurgical deficits in psychomotor and perceptual function result from the sedative drugs and not from the effects of local anesthetics or physiologic and psychological responses to surgery. These results also suggest that psychomotor tests are inappropriate measures of recovery and that superior sedation with rapid recovery may be achieved with reduced doses of longer acting agents such as diazepam and with the addition of shorter acting agents that do not prolong recovery.

Correlative histologic and serologic findings of sicca syndrome in patients with systemic lupus erythematosus.

We prospectively evaluated 24 patients with systemic lupus erythematosus for clinical, histologic, and serologic evidence of sicca syndrome. Abnormalties suggestive of sicca syndrome in patients with systemic lupus were identified by parotid scan (58%), questionnaire (54%), labial biopsy (50%), Schirmer's test (21%), and parotid flow rate (13%). An increased frequency of autoantibodies to gamma globulin and cellular antigen SS-A was detected in lupus patients with histologic changes on labial biopsy. The serologic findings are similar to those of patients with sicca syndrome alone with the exception of the reduced incidence of anti-SS-B in patients with systemic lupus.

Thrombophlebitis after intravenous use of anesthesia and sedation: its incidence and natural history.

A number of technical and clinical conditions reportedly associated with diazepam-related thrombophlebitis were investigated. Diazepam alone and in combination with fentanyl and methohexital was administered intravenously to 519 healthy, predominantly young adult patients undergoing routine oral surgery for removal of third molars. Indirect evidence is provided to show that two slightly different vasculopathies are involved: thrombophlebitis, in which pain and induration are both present but in which there is a slight delay in the time of inception of the condition; and phlebothrombosis, in which the reaction is almost immediate but pain is not significant and induration of the vein is the predominant feature. The overall incidence was 2.3% for thrombophlebitis and 9.8% for phlebothrombosis. There were four significant variables associated with phlebothrombosis: use of tobacco, use of oral contraceptives, multiple injections of diazepam, and pain during injection. The only significant variable associated with thrombophlebitis was the site of injection.

The relationship of smoking to localized osteitis.

The relationship between smoking and localized osteitis was studied in 200 patients who had 400 mandibular third molars removed. Information on how much patients smoked each day and whether cigaretts, cigars, or a pipe was smoked, as well as the postoperative smoking habits of each patient, was recorded. Results indicated that there is a signficant difference in the incidence of postoperative localized osteitis at extraction sites of mandibular third molars between smokers and nonsmokers; smoking after extraction caused a definite increase in the incidence of localized osteitis.

Comparison of recovery tests after intravenous sedation with diazepam-methohexital and diazepam-methohexital and fentanyl.

A model for the assessment of recovery to street fitness from two commonly used techniques for intravenous sedation is described. Well-known psychometric research methods and simple paper-and-pencil tests that could be given by interested clinicians were used. The speed of recovery from diazepam-methohexital, and diazepam-methohexital and fentanyl (with naloxine reversal), did not differ significantly. Psychomotor skills were recovered before both perceptual and cognitive functions. Two simple paper-and-pencil tests easily identified perceptual and cognitive deficits at least three hours postoperatively.

Predisposing and operative factors: effect on the incidence of localized osteitis in mandibular third-molar surgery.

Five hundred and four bilateral mandibular third-molar extraction sites were examined postoperatively for localized osteitis. All sites received a mechanical lavage of either 350 ml, or 175 ml. of sterile normal saline solution. No significant differences were observed relative to the effect of lavage volume on the incidence of iocalized osteitis. A preoperative antimicrobial mouthrinse of chloramine-T (sodium-p-toluene sulfonchloramide) was also used by one half of the patients. Although only slight differences were noted in healing with the different lavage volumes of the chloramine-T, certain predisposing factors contributed significant differences.

Conscious sedation with intravenous drugs: a study of amnesia.

A comparison of amnesia that is produced by two intravenous sedation techniques commonly used to reduce anxiety in ambulatory oral surgery patients showed that both techniques induce high levels of safe, predictable amnesia. More than 200 patients undergoing surgical extraction of third molars were asked to verbally identify visual and cutaneous-tactile stimuli intraoperatively. The patients responded via written questionnaires at the postoperative interview sessions. No retrograde amnesia was observed. Complete amnesia was attained for the local anesthetic injections. Amnesia for visual stimuli was significantly lower than for cutaneous-tactile stimuli. No significant differences in amnesia were observed between the two drug combinations studied.

Nitroblue tetrazolium and Limulus assays for bacteremia after dental extraction: effect of topical antiseptics.

Bacteremia that occurs after dental extraction is common. This study assessed the effect of topical antisepsis on the incidence and magnitude of post-extraction bacteremia. On hundred patients scheduled for elective tooth extraction were randomized among four groups: contr-l, mouthrinsing with sodium-p-toluene sulfonchloramide (chloramine-T), toothbrushing with chloramine-T, and irrigation with Lugol's solution. The results showed that 84% of the control group and 59% of the treatment groups had positive blood cultures (290 organisms isolated) after dental extraction. The duration and magnitude of these bacteremias were diminutive as documented by the six serial blood cultures taken for each patient, colony counts per milliliter of blood, and nitroblue tetrazolium and Limulus assays. Brushing the teeth or rinsing the mouth with chloramine-T before dental extraction significantly reduced the incidence of bacteremia (P less than .025) and the number of different organisms recovered from each patient (P less than .05). Thus, topical treatment with chloramine-T is a simple and effective means of reducing the incidence of postextraction bacteremia.

Sjögren-type syndrome after allogeneic bone-marrow transplantation.

Four patients, treated for hematologic disorders with bone-marrow transplants from HLA-identical siblings, spontaneously complained of dry eyes 8 to 12 months after transplantation. Four allograft recipients and two recipients of autologous bone-marrow transplants were evaluated for xerophthalmia and xerostomia. Three allogeneic marrow recipients had evidence of keratoconjunctivitis sicca, and two had decreased parotid gland function. All four allograft recipients had minor salivary gland histopathology identical to that of Sjögren's syndrome. The severity of symptoms and histologic lesions corresponded with the severity of chronic graft-versus-host disease. In addition, one patient developed sclerodermatous skin changes, another had discoid lupus erythematosus, and two patients had laboratory evidence of cholestasis. None of the patients had autoantibodies but all had hypergammaglobulinemia. In contrast, none of the recipients of autologous bone marrow had clinical, laboratory, or histologic findings resembling Sjögren's syndrome.