Larvicidal activity of the skin secretion of Rhinella marina and Rhaebo guttatus (Anura: Bufonidae) against the Brazilian malaria vector, Anopheles darlingi (Diptera: Culicidae)

@#Malaria, a mosquito-borne disease, is caused by protozoa of the genus Plasmodium and constitutes a serious public health problem. Because current insecticides used to control malaria face resistance due to continuous use, new alternatives are prompted. Considering this context, and the insecticidal potential of vertebrate venoms/secretions, crude and methanolic extracts from two frog species were tested as larvicides against Anopheles darlingi. Skin secretions of Rhinella marina and Rhaebo guttatus were obtained by manual stimulation. Then, methanol was added to obtain steroidal fractions from both venoms. Mosquitos were captured in suburban areas of Porto Velho and An. darlingi females were later fed with blood and stimulated to oviposit. The larvae were fed with fish food until the 3rd and 4th instars. For the larvicidal assays, crude secretions and methanolic fractions of both frog species were evaluated, and larvae mortality was recorded after 48 hours. Crude extracts and steroidal fractions from both species had larvicidal effects, with an LC50 of 127.5 and 133 ppm for the crude extract and steroidal fraction of R. marina, and an LC50 of 37.5 and 35.8 ppm for the crude extract and steroidal secretion of R. guttatus, respectively. The present work reports for the first time the larvicidal effects of the skin secretions from bufonid species occurring in the western Amazon region. Further studies should be carried out to investigate the purified components responsible for the observed activity.

Effect of different food and sugar sources on the larval biology and adult longevity of Anopheles darlingi (Diptera: Culicidae).

Anopheles darlingi is the main vector of the disease in the Amazon, and several studies on its ecology and behavior have been conducted. Although the basic nutritional requirements of insects are well known, quantitative needs with respect to food components and their balance vary among insect species; therefore, such information is needed in order to improve insect rearing for mass production. The present work evaluated the effect of different animal diets on larval biology and the utilization of different sugar sources in An. darlingi adults. First instar larvae obtained from wild-captured mosquitoes were reared in plastic trays containing 1 L of water and fed daily according to their larval instar stage with different commercial diets for fish, reptiles, and dogs, as well as a manipulated diet including Macapo. Larval mortality was recorded daily, and development time was calculated as the time required for 50% of the larvae to reach the last larval instar. Pupae and adults produced from larvae fed with different animal diets were also counted daily. Adults were fed with 10% sugar solutions of honey, sucrose, and sugar cane molasses, and longevity was recorded. Larval mortality was reduced for larvae feeding on fish food (higher protein content) compared to those fed with dog food (lower protein content) in later instars; the first and third instars presented a higher mortality than other instars, regardless of the food provided. Larval development time was reduced in larvae fed with fish food compared with dog food. The average daily production of pupae and adults were significantly higher in the treatment using fish food than in all other diet treatments. In general, adults from larvae fed on fish food and those that ingested honey as an adult sugar source lived longer than those reared on other treatments. Fish food, i.e., Tetramin Tropical Flakes, for larvae and honey, as a carbohydrate source for adults, seem to better support the rearing of Anopheles darlingi under our experimental conditions.

Effect of different food and sugar sources on the larval biology and adult longevity of Anopheles darlingi (Diptera: Culicidae)

@#Anopheles darlingi is the main vector of the disease in the Amazon, and several studies on its ecology and behavior have been conducted. Although the basic nutritional requirements of insects are well known, quantitative needs with respect to food components and their balance vary among insect species; therefore, such information is needed in order to improve insect rearing for mass production. The present work evaluated the effect of different animal diets on larval biology and the utilization of different sugar sources in An. darlingi adults. First instar larvae obtained from wild-captured mosquitoes were reared in plastic trays containing 1 L of water and fed daily according to their larval instar stage with different commercial diets for fish, reptiles, and dogs, as well as a manipulated diet including Macapo. Larval mortality was recorded daily, and development time was calculated as the time required for 50% of the larvae to reach the last larval instar. Pupae and adults produced from larvae fed with different animal diets were also counted daily. Adults were fed with 10% sugar solutions of honey, sucrose, and sugar cane molasses, and longevity was recorded. Larval mortality was reduced for larvae feeding on fish food (higher protein content) compared to those fed with dog food (lower protein content) in later instars; the first and third instars presented a higher mortality than other instars, regardless of the food provided. Larval development time was reduced in larvae fed with fish food compared with dog food. The average daily production of pupae and adults were significantly higher in the treatment using fish food than in all other diet treatments. In general, adults from larvae fed on fish food and those that ingested honey as an adult sugar source lived longer than those reared on other treatments. Fish food, i.e., Tetramin Tropical Flakes, for larvae and honey, as a carbohydrate source for adults, seem to better support the rearing of Anopheles darlingi under our experimental conditions.

Ceramic Inlays: Effect of Mechanical Cycling and Ceramic Type on Restoration-dentin Bond Strength.

This study aimed to evaluate the bond strength between dentin and five different ceramic inlays in permanent maxillary premolars, with and without mechanical cycling. One hundred permanent maxillary premolars were prepared and divided into 10 groups (n=10) according to the ceramic system (IPS e.Max Press; IPS e.Max CAD; Vita PM9; Vita Mark II; and Vita VM7) and the mechanical cycling factor (with and without [100 N, 2 Hz, 1.2×10(6) cycles]). The inlays were adhesively cemented, and all of the specimens were cut into microbars (1×1 mm, nontrimming method), which were tested under microtensile loading. The failure mode was classified and contact angle, roughness, and microtopographic analyses were performed on each ceramic surface. The mechanical cycling had a significant effect (p=0.0087) on the bond strength between dentin and IPS e.max Press. The Vita Mark II group had the highest bond strength values under both conditions, with mechanical cycling (9.7±1.8 MPa) and without (8.2±1.9 MPa), while IPS e.Max CAD had the lowest values (2.6±1.6 and 2.2±1.4, respectively). The adhesive failure mode at the ceramic/cement interface was the most frequent. Vita Mark II showed the highest value of average roughness. IPS e.max Press and Vita Mark II ceramics presented the lowest contact angles. In conclusion, the composition and manufacturing process of ceramics seem to have an influence on the ceramic surface and resin cement bond strength. Mechanical cycling did not cause significant degradation on the dentin and ceramic bond strength under the configuration used.

Trans-enamel and trans-dentinal cytotoxic effects of a 35% H2O2 bleaching gel on cultured odontoblast cell lines after consecutive applications.

AIM: To evaluate the trans-enamel and trans-dentinal cytotoxic effects of a 35% H(2)O(2) bleaching gel on an odontoblast-like cell lines (MDPC-23) after consecutive applications. METHODOLOGY: Fifteen enamel/dentine discs were obtained from bovine central incisor teeth and placed individually in artificial pulp chambers. Three groups (n = 5 discs) were formed according to the following enamel treatments: G1: 35% H(2)O(2) bleaching gel (15 min); G2: 35% H(2)O(2) bleaching gel (15 min) + halogen light (20 s); G3: control (no treatment). After repeating the treatments three consecutive times, the extracts (culture medium + gel components that had diffused through enamel/dentine discs) in contact with the dentine were collected and applied to previously cultured MDPC-23 cells (50 000 cells cm(-2)) for 24 h. Cell metabolism was evaluated by the MTT assay and data were analysed statistically (alpha = 5%; Kruskal-Wallis and Mann-Whitney U-test). Cell morphology was analysed by scanning electron microscopy. RESULTS: Cell metabolism decreased by 92.03% and 82.47% in G1 and G2 respectively. G1 and G2 differed significantly (P < 0.05) from G3. Regardless of halogen light activation, the application of the bleaching gel on the cultured odontoblast-like cells caused significantly more severe cytotoxic effects than those observed in the nontreated control group. In addition, significant morphological cell alterations were observed in G1 and G2. CONCLUSION: After three consecutive applications of a 35% H(2)O(2) bleaching agent, the diffusion of the gel components through enamel and dentine caused severe toxic effects to cultured pulp cells.

Exchange of a posterior chamber phakic intraocular lens in a highly myopic eye.

A 38-year-old woman had posterior chamber phakic intraocular lens (IOL) implantation as a secondary refractive procedure to correct residual refraction (20/50 with -16.50 -1.50 x 80) in May 1998, 3 years after intrastromal corneal ring segment surgery for high myopia (-30.00 diopters). Ultrasound biomicroscopy revealed an oversized lens, leading to malpositioning. Moreover, the patient remained undercorrected (20/40 with -5.25 -0.75 x 120). Ten months later, the phakic IOL was uneventfully exchanged for a shorter one with the correct dioptric power. It was well placed in the posterior chamber. The patient's visual acuity was 20/30 with -2.25 -0.75 x 145, very close to the refraction in the fellow aphakic eye (20/30 with -2.50 -0.75 x 75). Patient satisfaction with the final visual outcome was high. Accurate ciliary sulcus measurement is critical for proper phakic IOL sizing.

Cataract formation after posterior chamber phakic intraocular lens implantation.

Posterior chamber phakic intraocular lens (PCP IOL) implantation is an emerging refractive procedure. We report a case of cataract formation 6 months after uneventful implantation of a Staar PCP IOL to correct high myopia. Visual recovery was achieved after explantation of the phakic IOL and phacoemulsification with implantation of a foldable IOL through the same unenlarged self-sealing corneal incision.

Ultrasound biomicroscopic imaging of posterior chamber phakic intraocular lens.

BACKGROUND: Phakic intraocular lens (IOL) implantation represents a major technique for the correction of high myopia. The STAAR collamer posterior chamber phakic IOL--trade named Implantable Contact Lens--is an emerging technology in refractive surgery. We studied the relative position of the posterior chamber phakic IOL using ultrasound biomicroscopy. METHODS: The posterior chamber phakic intraocular lens was inserted in 9 eyes of 8 patients with high myopia. Ultrasound biomicroscopy was performed before and after implantation of the phakic IOL to assess its relative position in the anterior segment of the eye. The parameters measured and compared were anterior chamber depth, angle opening distance 500 microns from the scleral spur, iris-crystalline lens contact distance, iris-IOL contact distance, and IOL-crystalline lens distance. RESULTS: Ultrasound biomicroscopy showed contact between the iris and the IOL in all eyes and between the IOL and the crystalline lens in 8 eyes. Reduction in the anterior chamber depth and localized narrowing of the angle opening were observed in all eyes. CONCLUSION: IOL-iris touch, IOL-crystalline lens touch, and anterior chamber shallowing raise concerns of pigmentary dispersion, cataractogenesis, and narrow angle glaucoma following posterior chamber phakic intraocular lens implantation. Clinical data are needed to determine if these problems occur.

Benefit of against-the-rule astigmatism to uncorrected near acuity.

PURPOSE: To determine whether with-the-rule (WTR) or against-the-rule (ATR) astigmatism gives a better visual outcome after cataract and intraocular lens (IOL) implantation surgery by comparing the uncorrected distance and near visual acuities in eyes with low, simple, myopic residual astigmatism. SETTING: S. Geraldo Eye Hospital, Federal University of Minas Gerais, Belo Horizonte, Brazil. METHODS: Two groups of 10 eyes each, one with WTR and the other with ATR simple, myopic astigmatism, were studied after uneventful cataract and IOL implantation surgery. All patients had an uncorrected distance visual acuity of 20/40 or better. The negative cylinder ranged from 1.00 to 1.50 diopters (D). The uncorrected distance and near visual acuities of the two groups were compared. RESULTS: There was no statistically significant between-group difference in uncorrected distance visual acuity. However, for uncorrected near, the difference between groups was highly statistically significant (P < .001). Patients with ATR astigmatism had much better uncorrected near acuity than those with WTR astigmatism. CONCLUSION: In pseudophakia, low, simple, ATR myopic astigmatism is better than WTR astigmatism because it provides superior uncorrected near visual acuity.