In vitro biomechanical comparison of six different fixation methods following 5-mm sagittal split advancement osteotomies.

The sagittal split ramus osteotomy (SSRO) is a surgical technique used widely to treat many congenital and acquired mandibular discrepancies. Stabilization of the osteotomy site and the potential for skeletal relapse after the procedure are still major problems. The aim of this study was to compare the mechanical stability of six methods of rigid fixation in SSRO using a biomechanical test model. Sixty polyurethane replicas of human hemimandibles were divided into six groups. In group I, the osteotomies were fixed with two four-hole titanium miniplates; in group II, with one four-hole miniplate; in group III, with one four-hole miniplate+a bicortical screw; in group IV, with a grid miniplate; in group V, with a four-hole locking miniplate; and in group VI, with a six-hole miniplate. A linear load in the premolar region was applied to the hemimandibles. The resistance forces (N) needed to displace the distal segment by 1, 3, and 5mm were recorded and the data transmitted from the load cell to a computer. One-way analysis of variance with Tukey's post hoc test was performed to compare the means between groups. For the three displacement conditions, there was a strong tendency for the 2.0-mm plate+screw and the grid plate to have higher values.

Effect of the number of screws on the stability of locking mandibular reconstruction plates.

Atrophic mandible fractures are frequently a challenge to stabilize. This study evaluated, through mechanical testing in vitro, the number of locking screws that is sufficient to withstand loading when applied with a locking reconstruction plate in the fixation of atrophic mandible fractures. Polyurethane mandibles with a simulated linear fracture at the midline were used as substratum. Results show that resistance of the fixation is poor when one and two screws are used on each side of the fracture. Three screws on each side of the fracture significantly increases the resistance to displacement. However, no additional strength is added to the construct when more than three screws per side are used.

Lamivudine permeability study: a comparison between PAMPA, ex vivo and in situ Single-Pass Intestinal Perfusion (SPIP) in rat jejunum.

In order to reach the bloodstream and thus the target receptor, an orally-administered drug must first cross the intestinal barrier, which can occur via a paracellular, passive transcellular, or carrier-mediated uptake and/or efflux process (active or concentration gradient-driven). Our work aimed to explore the transport mechanism of the antiretroviral lamivudine (deoxycytidine nucleoside analogue), using a three-part strategy: in vitro, an ex vivo and an in situ method, represented by PAMPA, rat jejunum patches and rat Single Pass Intestinal Perfusion (SPIP), respectively. The determined permeability coefficients were compared with those from a published Caco-2 and MDCK study. Computational prediction of human jejunal permeability was explored, using various non-human permeability coefficients as descriptors. The ex vivo technique was performed in Franz-type diffusion cells, mounted with male Wistar rat jejunum segment patches. PAMPA was performed with an acceptor solution simulating the binding of serum proteins, an artificial membrane impregnated with egg lecithin/cholesterol and a gradient of pH between donor and acceptor solutions. The SPIP was conducted by proximal jejunum cannulation and drug perfusion in a constant flow rate of 0.2 mL/min. The outcomes of our studies showed the following predicted pattern for lamivudine effective jejunal permeability: P(eff)(exvivoA>B)>P(eff)(SPIP)>P(eff)(exvivo B>A)>P(eff)(Caco-2)≈P(eff)(MDCK)≈P(eff)(PAMPA), strongly suggesting that this compound has carrier-mediated uptake as its dominant transport mechanism. Notwithstanding, Caco-2 cells may indicate an under-expression of uptake transporters and possibly an over-expression efflux transporters, compared to that found in the rat jejunum.

Effect of compression load and temperature on thermomechanical tests for gutta-percha and Resilon®.

AIM: To analyse a method used to evaluate the thermomechanical properties of gutta-percha and Resilon(®) at different temperatures and compression loads. METHODOLOGY: Two hundred and seventy specimens measuring 10 mm in diameter and 1.5 mm in height were made from the following materials: conventional gutta-percha (GCO), thermoplastic gutta-percha (GTP) and Resilon(®) cones (RE). After 24 h, the specimens were placed in water at 50 °C, 60 °C or 70 °C for 60 s. After that, specimens were placed between two glass slabs, and loads weighing 1.0, 3.0 or 5.0 kg were applied. Images of the specimens were digitized before and after the test and analysed using imaging software to determine their initial and final areas. The thermomechanical property of each material was determined by the difference between the initial and final areas of the specimens. Data were subjected to anova and SNK tests at 5% significance. To verify a possible correlation between the results of the materials, linear regression coefficients (r) were calculated. RESULTS: Data showed higher flow area values for RE under all compression loads at 70 °C and under the 5.0 kg load at 60 °C (P < 0.05). Regarding gutta-percha, GTP showed higher flow under loads weighing 3.0 and 5.0 kg, at 60 and 70 °C (P < 0.05). GCO presented higher flow at 70 °C with a load of 5.0 kg. Regression analyses showed a poor linear correlation amongst the results of the materials under the different experimental conditions. CONCLUSION: Gutta-percha and Resilon(®) cones require different compression loads and temperatures for evaluation of their thermomechanical properties. For all materials, the greatest flow occurred at 70 °C under a load of 5.0 kg; therefore, these parameters may be adopted when evaluating endodontic filling materials.

Parallel artificial membrane permeability assay (PAMPA) - Is it better than Caco-2 for human passive permeability prediction?

This review proposes a statistical and qualitative comparison between the main techniques derived from the original PAMPA method and experimental results obtained from Caco-2 and human jejunum. Among them, PAMPA techniques variations developed by some of the most renowned authors on the subject. The comparison is made from 16 common structurally diverse molecules, taking into account mainly membrane lipid composition and incubation conditions. A BCS classification prediction of the studied molecules was also possible to make. Finally, it was possible to raise and prove important previous hypotheses, aside from pointing out the best PAMPA model to predict human data.

Fracture strength of bovine incisors after intra-radicular treatment with MTA in an experimental immature tooth model.

AIM: To evaluate, using an experimental immature tooth model, the fracture resistance of bovine incisors submitted to different reinforcement treatments with mineral trioxide aggregate (MTA). METHODOLOGY: An immature tooth model was created by sectioning the coronal and apical portions of 40 bovine incisors 8 mm above and 12 mm below the cementoenamel junction. The root canals were irrigated with 1.0% sodium hypochlorite. They were enlarged both coronally and apically using number 703 carbide burs (ISO: 500-104-168-007-021) and their internal diameter was standardized to 2.1 mm. The specimens were assigned to four groups (n = 10): GI-control (without filling); GII-apical MTA plug + filling with gutta-percha and endodontic sealer; GIII-filling with MTA; GIV-apical MTA plug + filling with MTA + metallic post (Reforpost I). A polyether impression material was used to simulate the periodontal ligament. The specimens were submitted to a compressive load at a crosshead speed of 0.5 mm min(-1) in a servo-hydraulic universal testing machine (MTS 810) applied at 45 degrees to the long axis of the tooth until failure. Data were submitted to statistical analysis by the Kruskal-Wallis test at 5% significance level. RESULTS: GIV presented the highest fracture resistance (32.7N) and differed significantly from the other groups (P < 0.05). No statistically difference was found between GII (16.6N) and GIII (23.4N) (P > 0.05). GIII had a significantly higher fracture resistance than GI (P < 0.05). CONCLUSIONS: The use of MTA + metallic post as an intra-radicular reinforcement treatment increased the resistance to fracture of weakened bovine teeth in an experimental immature tooth model.

The value of a second injection on the pharmaco-induced erection test.

In order to test the capability of a reinjection to improve an incomplete pharmaco-induced erection, we submitted 30 impotent patients, with incomplete erectile responses to 10 micrograms PGE1 + 1 mg phentolamine, to a second injection of 15 micrograms PGE1 + 1.5 mg phentolamine + 30 mg papaverine, fifteen minutes after the first injection. Twenty-one patients improved their erection including nine who achieved complete rigidity. We conclude that incomplete pharmaco-induced erections can frequently be improved by reinjection.

Evidence for the presence of two (Ca(2+)-Mg2+) ATPases with different sensitivities to thapsigargin and cyclopiazonic acid in the human flatworm Schistosoma mansoni.

The subcellular localization of the (Ca(2+)-Mg2+)ATPase activities present in heterogeneous (P1), nuclear (P2), mitochondrial (P3) and microsomal (P4) fractions obtained by differential centrifugation of Schistosoma mansoni homogenate was investigated. In the microsomal fraction (P4), the (Ca(2+)-Mg2+)ATPase activity was completely blocked by 3 microM thapsigargin, whereas in the more heterogeneous fraction (P1), about 20-30% of this activity was resistant to the drug. The same pattern of inhibition was observed using 20 microM cyclopiazonic acid. The distribution pattern of (Ca(2+)-Mg2+)ATPase activity among the four subcellular fractions (P1 > P4 > > P3 > P2) was completely different from that of [3H]-ouabain binding sites (P1 > or = P4 = P2 > or = P3). These results indicate that the (Ca(2+)-Mg2+)ATPase in S. mansoni is predominantly of the SERCA type (localized in the endoplasmic reticulum). However, there is another enzyme, present in lower proportion that could have a plasma membrane origin (PMCA type), because it is resistant to thapsigargin and cyclopiazonic acid and its inhibition by tamoxifen is antagonized by calmodulin.

Nasal tip repair with axial flap of nasal muscle.

The procedure described here consists of a myocutaneous axial flap with lateral pedicle. It uses the transverse part of the nasal muscle that goes forward in rotation and the lateral and superior portions of the flap in the V-Y. The procedure is useful for repairing losses of nasal tip and the surrounding area. It is a simple method that can be used to reconstruct the brim near the tip of the nose, yielding an aesthetically and functionally efficient nose.

Effect of an NK1 receptor antagonist (CP-99,994) on hypertonic saline-induced bronchoconstriction and cough in male asthmatic subjects.

To investigate the role of NK1 receptors in the pathogenesis of bronchoconstriction and cough in asthma, we performed a randomized, double-blind, crossover study on the effects of a selective non-peptide tachykinin NK1 receptor antagonist (CP-99,994) on baseline measures of lung function and on hypertonic saline-induced bronchoconstriction and cough in 14 male subjects with mild asthma. CP-99,994 (250 micrograms/2 hours) and placebo were administered intravenously in 2-h infusions during consecutive visits 5 to 7 d apart. Specific airway resistance (SRaw) was measured and spirometry was performed at baseline and at 35 and 60 min. Next, hypertonic saline challenge was performed by delivering 10 breaths of saline of increasing concentration (0.9 to 7% in 1% increments at 5-min intervals) via an ultrasonic nebulizer until SRaw increased from baseline by 200% or 20 units, whichever was greater. Throughout the challenge cough was counted from a taped record made from two microphones placed close to the subject's larynx. We found that CP-99,994 did not significantly affect SRaw or spirometric measures of lung function during the first hour of infusion. Although CP-99,994 infusion markedly attenuated the bronchoconstrictor response to the saline challenge in two subjects, it did not significantly decrease the area under curves obtained for SRaw and cough during saline challenge for the group as a whole (p = 0.9 for SRaw;p = 0.8 for cough). We conclude that administration of 250 micrograms/kg of CP-99,994 over 2 h does not significantly inhibit hypertonic saline-induced bronchoconstriction or cough in subjects with mild asthma and does not have acute bronchodilator activity in these subjects.

Veno-occlusive dysfunction of corpora cavernosa: comparison of diagnostic methods.

Pump cavernosometry, pharmaco-cavernosometry, gravity cavernosometry and the intracavernous pressure drop test are the most used tests for the diagnosis of venoocclusive dysfunction. To verify whether patients show equivalent results in each of these four tests, and to ascertain whether there is any influence of the sequence of the exams over the results, 123 male patients with erectile dysfunction, aged 21 to 82 years (mean 48), were evaluated. All were submitted to the four tests in randomized sequence. Two criteria were used to define the normal results of pump cavernosometry and pharmaco-cavernosometry, both based on patients with normal veno-occlusive function. The incidence of normal results varied from 6.5% in pump cavernosometry according to criterion I to 64.2% in pharmaco-cavernosometry according to criterion II. Results of the four tests agreed completely (all normal or all abnormal) in 43.9% of the patients when criteria I was used and 58.3% with criteria II. Incidence of normal results in each test did not vary according to the sequence in which the exams were done. Pump cavernosometry, pharmaco-cavernosometry, gravity cavernosometry and intracavernous pressure drop test did not show equivalent results for individual patients. Results were not influenced by the sequence of the tests.

Penile prosthesis surgery with the patient under local regional anesthesia.

A total of 20 patients underwent penile prosthesis implantation while under local regional anesthesia with a pudendal nerve blockade at the perineum. The method is safe, performed as an outpatient procedure and showed no complication. It avoids the need to inject a local anesthetic intracorporeally, which is risky in elderly patients.

Surgical exclusion of the crural ending of the corpora cavernosa: late results.

Twenty-three patients with corpora cavernosa incompetence responsive to perineal compression were submitted to surgical exclusion of the crural ending of the corpora cavernosa. There were two mild complications: perineal hematoma and incisional pain for 10 days. At the end of the first month, 65% of the patients claimed better erections, and the late good results were 47.7%, with an average follow-up period of 18.9 months. Three of the failed cases were later submitted to a penile prosthesis implantation.

Impact of cigarette smoking on papaverine-induced erection.

Owing to the vasoconstrictive effect of nicotine, smoking may potentially interfere in the results of the drug-induced erection test for papaverine hydrochloride. To investigate the effect of smoking on this test, 12 patients between 22 and 65 years old underwent the following protocol: phase 1--intracavernous injection of 100 mg. papaverine hydrochloride with measurement of intracavernous pressure by puncture with a 19 caliber butterfly needle attached to an aneroid manometer and phase 2--1 week after the initial test the procedure was repeated after the patient smoked 2 cigarettes. In phase 1 all men obtained a full erection, compared to only 4 in phase 2. The average intracavernous pressures were 85.83 and 53.50 mm. Hg, respectively, in phases 1 and 2 (p less than 0.01). We conclude that cigarette smoking, probably through nicotine, interferes with the drug-induced erection test, which might explain some false negative results.

Simultaneous in vitro fertilization and gamete intrafallopian transfer (GIFT).

During a 6-month period, a combination of gamete intrafallopian transfer (GIFT) and in vitro fertilization (IVF) was offered to all couples beginning an IVF treatment cycle in whom the wife had anatomically normal fallopian tubes. It was recommended to these couples that sufficient oocytes be reserved for insemination in vitro to determine whether the husband's spermatozoa could fertilize the wife's oocytes. During this interval, 16 couples underwent the combined IVF-GIFT procedure. All of the IVF-GIFT couples had at least two oocytes inseminated in vitro and at least two oocytes for GIFT. Of the 16 IVF-GIFT couples, only 1 (6.25%) achieved a clinical pregnancy. More important, 50% (8/16) of the IVF-GIFT couples had no oocytes fertilized in vitro. With the information concerning lack of fertilization in vitro, appropriate recommendations concerning future fertility management can be made. If the same couples had undergone the GIFT procedure alone, without additional oocytes fertilized in vitro, this information would not have been obtained.

Leakage through the crural edge of corpus cavernosum. Diagnosis and treatment.

Blood drainage of the corpora cavernosa is made by the deep dorsal vein and by the deep crural veins. The root of the corpora can be compressed against the ischium during papaverine test or cavernometry. In a series of patients with cavernosal leakage, this maneuver demonstrated that the crural edge of the corpora is the point of leakage in many of them. Exclusion of the crural edge by ligation of the corpora proximal to the entrance of the arterial supply caused improvement of erections in 7 of 8 patients.

Comparacao das curvas de diluicao do tempo de protrombina e do tempo de tromboplastina parcial ativada para controle do efeito das antivitaminas K. / Comparison between the dilution curves of prothrombin time and activated partial thromboplastin time for the control of the effect of anti-vitamins K

O tempo de tromboplastina parcial ativada (TTPA) vem sendo utilizado com metodo alternativo ao tempo de protrombina (TP) para controle do uso clinico das antivitaminas K. No caso do TP considera-se como sendo a faixa da seguranca as atividades protrombinicas entre 15 e 30% do normal.Com relacao ao TTPA considera-se qualquer valor acima do limite superior a normalidade como indicativo de hipocoagulacao nao existindo referencias sobre uma faixa de seguranca para controle do uso das antivitaminas K. Neste trabalho adotou-se para o TTPA o mesmo procedimento de avaliacao da atividade protrombinica, ou seja, obtencao de TTPA de diluicoes de plasma normal com solucao fisiologica e com plasma adsorvido Para tanto, foram estudadas 16 curvas de diluicao em cada solvente, a partir de misturas com quatro plasmas de individuos normais. Obteve-se os valores de TTPA correspondentes as diluicoes que determinam a faixa de seruganca do TP. Embora devam ser considesiderados anticoagulantes todos os doentes com TTPA acima do limite superior da normalidade e possivel que a faixa de seguranca quando se utiliza este metodo, esteja entre 1,35 e 1,90 utilizando-se a relacao: TTPA das diluicoes entre 10 a 30% do normal/TTPA normal (100%)