Use of carbon dioxide (CO2) laser radiation in exposure of implants (stage II): A metallography evaluation in dogs

In this study we analyzed possible damages that vaporization from laser radiation could cause to implant material. Fifteen standard titanium implants, measuring 3.75 mm in diameter by 7 mm in length, were placed into the upper and lower jaws of three dogs according to Branemark's system. After osseointegration, all implants were exposed. In group I (control) conventional exposure with a punch was used; in group II, a CO2 laser with 2 W (power density: 256 W/cm(2); fluency: 0.077 J/cm(2), and a pulse mode of 0.30 ms) was used, and in group III 4 W (power density: 512 W/cm(2), fluency: 0.154 J/cm(2), and a pulse mode of 0.30 ms) was used. After vaporization, the cover screws were removed and sent for metallographic examination. The results showed that cover screws irradiated with 2 and 4 W power caused no superficial or microstructural alteration. The results also showed that the prescribed power densities, fluencies, and the use of the pulse mode were suitable for exposing implants without damage to tissue or implant material. (C) 2002 Laser Institute of America.

Treatment of ligature-induced peri-implantitis by lethal photosensitization and guided bone regeneration: A preliminary histologic study in dogs

Background: the purpose of this pilot study was to evaluate the healing potential and reosseointegration in ligature-induced peri-implantitis defects adjacent to various dental implant surfaces following lethal photosensitization.Methods: A total of 36 dental implants with 4 different surface coatings (9 commercially pure titanium surface [CPTi]; 9 titanium plasma-sprayed [TPS]; 9 hydroxyapatite [HA]; and 9 acid-etched [AE]) were inserted in 6 male mongrel dogs 3 months after extraction of mandibular premolars. After a 2-month period of ligature-induced peri-implantitis and 12 months of natural peri-implantitis progression, only 19 dental implants remained. The dogs underwent surgical debridement of the remaining dental implant sites and lethal photosensitization by combination of toluidine blue O (100 mug/ml) and irradiation with diode laser. All exposed dental implant surfaces and bone craters were meticulously cleaned by mechanical means, submitted to photodynamic therapy, and guided bone regeneration (GBR) using expanded polytetrafluoroethylene (ePTFE) membranes. Five months later, biopsies of the implant sites were dissected and prepared for ground sectioning and analysis.Results: the percentage of bone fill was HA: 48.28 +/- 15.00; TPS: 39.54 +/- 12.34; AE: 26.88 +/- 22.16; and CPTi: 26.70 +/- 16.50. The percentage of reosseointegration was TPS: 25.25 +/- 11.96; CPTi: 24.91 +/- 17.78; AE: 17.30 +/- 15.41; and HA: 15.83 +/- 9.64.Conclusion: These data suggest that lethal photosensitization may have potential in the treatment of peri-implantitis.

Effect of root canal filling material and level of surgical injury on periodontal healing in dogs

Some divergencies in the literature about periodontal healing after surgical injury stimulated the development of this experiment. The root canals of dogs' teeth were negotiated and filled by the lateral condensation technique with two kinds of sealers: Sealapex and zinc oxide-eugenol cement. In the second session, the bone tissue was exposed and one cavity was made at the apical third of the root and another at the border between the coronal and middle thirds, both penetrating into the root canal. Six months later the animals were sacrificed and the specimens prepared for histopathologic analysis. The results showed that the kind of filling material and the level of the periodontal wound exposing the root canal can influence the healing process (P<0.01).

Assessment of electrocardiographic parameters in healthy dogs undergoing dobutamine stress testing

The electrocardiographic effects of dobutamine stress testing (10 to 40 mu g/kg/minute) were investigated in five conscious healthy dogs. We studied the changes in the duration and amplitude of P wave, PR interval, duration of QRS complex, R wave amplitude, QT interval, and heart rate. Development of arrhythmias and ST segment abnormalities were also recorded. It was observed that dobutamine significantly affects atrioventricular-nodal conduction and total electrical systole time at higher infusion rates. Only a single episode of sustained ventricular tachycardia was observed, which was promptly restored to sinus rhythm shortly after dobutamine infusion was discontinued. No ST segment abnormalities were detected. Dobutamine stress testing was concluded to play a role in some ECG parameters at higher infusion rates.

Effects of travoprost 0.004% compared with latanoprost 0.005% on the intraocular pressure of normal dogs

Purpose To compare the effects of travoprost 0.004% and latanoprost 0.005% on the intraocular pressure (IOP) of normal dogs.Methods Twenty mixed breed dogs were randomized to two groups: latanoprost was used in group A and travoprost in group B. The drugs were instilled in the right eye of the dogs, whereas the left eye received placebo. Both drugs were instilled once a day at 8 AM during 5 days. IOP measurements were made at 8 AM, 10 AM, 2 PM and 8 PM during the 5 days of treatment, the 3 days that preceded treatment, and 3 days following treatment. Presence of blepharospasm, miosis, anterior chamber flare, and conjunctival hyperemia were evaluated during the study.Results Mean IOP was significantly reduced in the eyes treated with both latanoprost and travoprost, when compared with the eyes treated with placebo (P < 0.05). There was no statistically significant difference between the mean IOPs of eyes treated with latanoprost and travoprost at all time intervals during baseline, treatment, and recovery (P > 0.05). on the fifth day of treatment and on the first day of the recovery period, a severe ocular hypotension was noted with both drugs, resulting in imprecise readings with the tonometer. Miosis and conjunctival hyperemia were observed in the treated eyes of both groups, whereas flare was noticed in one latanoprost-treated eye.Conclusion Travoprost 0.004% significantly reduces the IOP in normal dogs. The hypotensive effect obtained with travoprost 0.004% is comparable to that obtained with latanoprost 0.005%.

Neurotoxicity of subarachnoid hyperbaric bupivacaine in dogs

Background and Objectives. The study investigated possible neurotoxic effects of increasing concentrations and doses of bupivacaine administered into the subarachnoid space in dogs. Methods. Fifty animals were allocated to five experimental groups: G1, control; G2, 5 mg 0.5 bupivacaine in 10% glucose solution; G3, 10 mg of 1% bupivacaine in 10% glucose solution; G4, 20 mg 2% bupivacaine in 10% glucose solution, and G5, 20 mg 2% bupivacaine in water. After 72 hours of observation, the animals were killed and the spinal cords removed for histologic examination by light microscopy. Results. None of the animals showed any neurologic clinical disturbance following recovery from spinal anesthesia. One case of necrosis of nerve tissue was observed in G3 and four in G4. Conclusions. Increasing concentrations and doses of hyperbaric bupivacaine solutions increased the incidence of nerve tissue damage, which did not occur with hypobaric solutions. These results should contribute to the further understanding of neurologic complications following spinal anesthesia when large doses of local anesthetics in hyperbaric solutions are used.

Virulence of Rhodococcus equi isolated from cats and dogs

Nine cat isolates and nine dog isolates of Rhodococcus equi from clinical material were investigated for the presence of the virulence-associated antigens (VapA and VapB) and virulence plasmids. Five of the cat isolates and one dog isolate were VapA positive and contained an 85-kb type I or an 87-kb type I plasmid. The remaining 12 isolates were avirulent R. equi strains and contained no virulence plasmids.

Evaluation of intraocular pressure in association with cardiovascular parameters in normocapnic dogs anesthetized with sevoflurane and desflurane

The objective of this study was to determine intraocular pressure (IOP) and cardiac changes in normocapnic dogs maintained under controlled ventilation and anesthetized using sevoflurane or desflurane. Sixteen healthy adult mixed-breed dogs, seven males and nine females, weighing 10-15 kg were used. The dogs were randomly assigned to one of two groups composed of eight animals anesthetized with sevoflurane (SEVO) or desflurane (DESF). In both groups, anesthesia was induced with propofol (10 mg/kg), and neuromuscular blockade was achieved with rocuronium (0.6 mg/kg/h IV). No premedication was given. Ventilation was adjusted to maintain end-tidal carbon dioxide partial pressure at 35 mmHg. Anesthesia was maintained with 1.5 minimum alveolar concentration (MAC) of sevoflurane or desflurane. In both groups IOP was measured by applanation tonometry (Tono-Pen) before induction of anesthesia. IOP, mean arterial pressure (MAP), heart rate (HR), cardiac index (CI) and central venous pressure (CVP) were also measured 45 min after the beginning of inhalant anesthesia and then every 20 min for 60 min. A one-way repeated measures ANOVA was used to compare data within the same group and Student's t-test was used to assess differences between groups. P < 0.05 was considered statistically significant. Measurements showed normal IOP values in both groups, even though IOP increased significantly from baseline during the use of desflurane. IOP did not differ between groups. CI in the desflurane group was significantly greater than in the sevoflurane group. Sevoflurane and desflurane have no clinically significant effects on IOP, MAP, HR, CI or VCP in the dog.

Ocular alterations in dogs naturally infected by Leishmania (Leishmania) chagasi

Ocular conditions, anti-Leishmania antibodies and total protein of the aqueous humor were studied in dogs naturally infected by Leishmania ( Leishmania) chagasi. Fifty dogs were analyzed and assigned into two groups of 25 animals each. All animals were submitted to routine ophthalmic exam. Results showed that 76% of the affected animals presented ocular signs, being uveitis the predominant. The mean of total protein in the aqueous humor of animals with uveitis was higher ( P < 0.05) when compared to the mean of animals with other ocular signs or no clinical sign. The anti- Leishmania chagasi antibody values in plasma were superior to those found in the aqueous humor (P < 0.05).

Evaluation of serological tests for the diagnosis of Neospora caninum infection in dogs: Optimization of cut off titers and inhibition studies of cross-reactivity with Toxoplasma gondii

Diagnosis of Neospora caninum infection in dogs is based on serological assays such as the indirect fluorescent antibody test (IFAT) and enzyme-linked immunosorbent assays (ELISA). This study evaluated two serological tests (IFAT and ELISA) for the detection of IgG antibodies to N. caninum in 300 serum samples of dogs through the optimization of cut off titers by using the two-graph receiveroperating characteristic (TG-ROC) curve. In addition, the identification of major cross-reactive antigens with Toxoplasma gondii was investigated by inhibition ELISA and immunoblotting (IB) assays. IFAT and ELISA results showed 74% agreement, with a good negative concordance (P-neg=0.83), but a poor positive concordance (P-pos=0.42). The great majority (86%) of sera with positive concordant results (IFAT+/ELISA+) recognized at least two out of three N. caninum immunodominant antigens, particularly the 29-32 and 35-37 kDa bands. Optimization of cut off titers in IFAT and ELISA was performed considering the reactivity to at least two out of three N. caninum immunodominant antigens as infection markers, obtaining a titer of 50 for IFAT and 200 for ELISA. Seropositivity to N. caninuin was significantly associated with T gondii-seropositive samples, particularly in ELISA (55.4%). Inhibition ELISA curves for N. caninum showed a partial heterologous inhibition, indicating some degree of cross-reactivity between N. caninum and T gondii antigens. Inhibition IB assays showed a moderate heterologous inhibition for N. caninum antigens above 45-50 kDa. These results indicate that ELISA should be used critically when crude tachyzoite antigen preparations are employed, due to possible cross-reactivity with other related parasites as T gondii. Also, the cut off dilution of 1:50 in IFAT showed to be the most appropriated for N. caninum serology in dogs. Therefore, we suggest that N. caninum immunodominant antigens, specially the 17 and 29-32 kDa proteins, should be selected markers in serological assays for canine neosporosis. (c) 2006 Elsevier B.V. All rights reserved.

Corneal endothelial cell morphology of normal dogs in different ages

Endothelial cell function is essential to maintain corneal transparency, but unfortunately the regenerative capacity of the endothelium is limited. There are only a few reports describing the effect of age on morphologic appearance of corneal endothelial cells of dogs. Studies of normal corneal endothelial cells in humans and dogs have shown a decrease in endothelial cell density (ECD) and an increase in pleomorphism and polymegethism with advancing age. The purpose of this study was to investigate the effect of age on ECD and endothelial cell morphology in dogs. A total of 30 dogs were divided into three groups (10 dogs/group) based on age: group 1 (2-12 months old), group 2 (24-72 months old), and group 3 (84 months or older). Corneas were processed for light and scanning electron microscopy. Results showed only difference in cell density between group 1 and groups 2 and 3, showing an initial decrease in cell density as the animal matured. Whereas there was significantly greater variation in cell size within the dogs in group 3 than there was within the other two groups, suggesting that there was increased polymegethism and pleomorphism with advancing age.

Comparison of two immunochromatographic assays and the indirect immunofluorscence antibody test for diagnosis of Trypanosoma cruzi infection in dogs in south central Louisiana

Two rapid tests evaluated in dogs considered to be of high risk of Infection with the Chagas parasite Trypanosoma cruzi using two immunochromatographic assays. Trypanosoma Detect (TM) for canine, InBios, Seattle, WA and CHAGAS STAT-PAK (TM) assay, Chembio Diagnostic Systems, Medford, NY, in south central Louisiana. For this purpose a serological survey was carried out in a total of 122 dogs and a serum bank was created. These 122 animals were first tested by IFAT that was used as the standard test From the serum bank 50 samples were tested using the two rapid Chagas assays and results compared to the standard test IFAT The serological survey using IFAT showed it prevalence of T cruzi infection in 22.1% of the tested dogs. In the immunochromatographic assays. 13 and 11 animals were positive on rapid assay Trypanosoma Detect (TM) for canine, InBios and CHAGAS STAT-PAK (TM), Chembio Diagnostic Systems, respectively compared to 11 positive by IFAT. These two immunochromatographic tests have shown high susceptibility and specificity compared to our standard method IFAT. The rapid, easy and accurate screening assays used in conjunction with confirmatory tests, would be an excellent tool for veterinarians to diagnose T cruzi infection. Early detection of T cruzi infection may prevent complications through an effective treatment. Greater awareness by veterinarians of the risk. clinical findings, history along with diagnostic methods will contribute greatly to an understanding of the true prevalence of Chagas disease in dogs in Louisiana. (c) 2009 Elsevier B.V. All rights reserved.