Sex Hormones Promote Opposite Effects on ACE and ACE2 Activity, Hypertrophy and Cardiac Contractility in Spontaneously Hypertensive Rats.

BACKGROUND: There is growing interest in sex differences and RAS components. However, whether gender influences cardiac angiotensin I-converting enzyme (ACE) and angiotensin-converting enzyme 2 (ACE2) activity is still unknown. In the present work, we determined the relationship between ACE and ACE2 activity, left ventricular function and gender in spontaneously hypertensive rats (SHRs). METHODOLOGY/PRINCIPAL FINDINGS: Twelve-week-old female (F) and male (M) SHRs were divided into 2 experimental groups (n = 7 in each group): sham (S) and gonadectomized (G). Fifty days after gonadectomy, we measured positive and negative first derivatives (dP/dt maximum left ventricle (LV) and dP/dt minimum LV, respectively), hypertrophy (morphometric analysis) and ACE and ACE2 catalytic activity (fluorimetrically). Expression of calcium handling proteins was measured by western blot. Male rats exhibited higher cardiac ACE and ACE2 activity as well as hypertrophy compared to female rats. Orchiectomy decreased the activity of these enzymes and hypertrophy, while ovariectomy increased hypertrophy and ACE2, but did not change ACE activity. For cardiac function, the male sham group had a lower +dP/dt than the female sham group. After gonadectomy, the +dP/dt increased in males and reduced in females. The male sham group had a lower -dP/dt than the female group. After gonadectomy, the -dP/dt increased in the male and decreased in the female groups when compared to the sham group. No difference was observed among the groups in SERCA2a protein expression. Gonadectomy increased protein expression of PLB (phospholamban) and the PLB to SERCA2a ratio in female rats, but did not change in male rats. CONCLUSION: Ovariectomy leads to increased cardiac hypertrophy, ACE2 activity, PLB expression and PLB to SERCA2a ratio, and worsening of hemodynamic variables, whereas in males the removal of testosterone has the opposite effects on RAS components.

Acute exposure to lead increases myocardial contractility independent of hypertension development.

We studied the effects of the acute administration of small doses of lead over time on hemodynamic parameters in anesthetized rats to determine if myocardial contractility changes are dependent or not on the development of hypertension. Male Wistar rats received 320 µg/kg lead acetate iv once, and their hemodynamic parameters were measured for 2 h. Cardiac contractility was evaluated in vitro using left ventricular papillary muscles as were Na+,K+-ATPase and myosin Ca2+-ATPase activities. Lead increased left- (control: 112 ± 3.7 vs lead: 129 ± 3.2 mmHg) and right-ventricular systolic pressures (control: 28 ± 1.2 vs lead: 34 ± 1.2 mmHg) significantly without modifying heart rate. Papillary muscles were exposed to 8 µM lead acetate and evaluated 60 min later. Isometric contractions increased (control: 0.546 ± 0.07 vs lead: 0.608 ± 0.06 g/mg) and time to peak tension decreased (control: 268 ± 13 vs lead: 227 ± 5.58 ms), but relaxation time was unchanged. Post-pause potentiation was similar between groups (n = 6 per group), suggesting no change in sarcoplasmic reticulum activity, evaluated indirectly by this protocol. After 1-h exposure to lead acetate, the papillary muscles became hyperactive in response to a ß-adrenergic agonist (10 µM isoproterenol). In addition, post-rest contractions decreased, suggesting a reduction in sarcolemmal calcium influx. The heart samples treated with 8 µM lead acetate presented increased Na+,K+-ATPase (approximately 140%, P < 0.05 for control vs lead) and myosin ATPase (approximately 30%, P < 0.05 for control vs lead) activity. Our results indicated that acute exposure to low lead concentrations produces direct positive inotropic and lusitropic effects on myocardial contractility and increases the right and left ventricular systolic pressure, thus potentially contributing to the early development of hypertension.

Antifungal activity of nanocapsule suspensions containing tea tree oil on the growth of Trichophyton rubrum.

The aim of this study was to evaluate, for the first time, the antifungal efficacy of nanocapsules and nanoemulsions containing Melaleuca alternifolia essential oil (tea tree oil) in an onychomycosis model. The antifungal activity of nanostructured formulations was evaluated against Trichophyton rubrum in two different in vitro models of dermatophyte nail infection. First, nail powder was infected with T. rubrum in a 96-well plate and then treated with the formulations. After 7 and 14 days, cell viability was verified. The plate counts for the samples were 2.37, 1.45 and 1.0 log CFU mL(-1) (emulsion, nanoemulsion containing tea tree oil and nanocapsules containing tea tree oil, respectively). A second model employed nails fragments which were infected with the microorganism and treated with the formulations. The diameter of fungal colony was measured. The areas obtained were 2.88 ± 2.08 mm(2), 14.59 ± 2.01 mm(2), 40.98 ± 2.76 mm(2) and 38.72 ± 1.22 mm(2) for the nanocapsules containing tea tree oil, nanoemulsion containing tea tree oil, emulsion and untreated nail, respectively. Nail infection models demonstrated the ability of the formulations to reduce T. rubrum growth, with the inclusion of oil in nanocapsules being most efficient.

Modified section method for laser-welding of ill-fitting cp Ti and Ni-Cr alloy one-piece cast implant-supported frameworks.

This study aimed to verify the effect of modified section method and laser-welding on the accuracy of fit of ill-fitting commercially pure titanium (cp Ti) and Ni-Cr alloy one-piece cast frameworks. Two sets of similar implant-supported frameworks were constructed. Both groups of six 3-unit implant-supported fixed partial dentures were cast as one-piece [I: Ni-Cr (control) and II: cp Ti] and evaluated for passive fitting in an optical microscope with both screws tightened and with only one screw tightened. All frameworks were then sectioned in the diagonal axis at the pontic region (III: Ni-Cr and IV: cp Ti). Sectioned frameworks were positioned in the matrix (10-Ncm torque) and laser-welded. Passive fitting was evaluated for the second time. Data were submitted to anova and Tukey-Kramer honestly significant difference tests (P < 0.05). With both screws tightened, one-piece cp Ti group II showed significantly higher misfit values (27.57 +/- 5.06 microm) than other groups (I: 11.19 +/- 2.54 microm, III: 12.88 +/- 2.93 microm, IV: 13.77 +/- 1.51 microm) (P < 0.05). In the single-screw-tightened test, with readings on the opposite side to the tightened side, Ni-Cr cast as one-piece (I: 58.66 +/- 14.30 microm) was significantly different from cp Ti group after diagonal section (IV: 27.51 +/- 8.28 microm) (P < 0.05). On the tightened side, no significant differences were found between groups (P > 0.05). Results showed that diagonally sectioning ill-fitting cp Ti frameworks lowers misfit levels of prosthetic implant-supported frameworks and also improves passivity levels of the same frameworks when compared to one-piece cast structures.

Castability and resistance of ceramometal bonding in Ni-Cr and Ni-Cr-Be alloys.

STATEMENT OF PROBLEM: Because of its pathogenic potential, the importance of the use of beryllium with Ni-Cr alloys must be determined. PURPOSE: This study compared fundamental properties for the clinical use of Ni-Cr alloys, determining the advantage of the addition of beryllium, despite the involved risks. MATERIAL AND METHODS: Two Be-free commercial alloys (Vera Bond II and Wiron 99) and 1 Be-free experimental alloy (E3) with Nb and/or Mo in their formulations and 1 experimental Ni-Cr alloy (E4) with 1.1% Be were submitted to ceramometal bonding resistance, castability, and hardness tests. RESULTS: Analysis of variance showed significant differences (P=.05) between Vera Bond II and Wiron 99 (Be-free) and the E4 alloy for the castability test. Vera Bond II, Wiron 99, and E4 presented higher castability values than E3. There were no statistically significant differences for the ceramometal bonding resistance test. The Kruskal-Wallis test showed significant differences (P=.01) among the alloys with Rockwell 30 T values for the hardness test. CONCLUSION: Within the limitations of this study, the presence of Be in Ni-Cr alloys was not necessary to guarantee the castability and the ceramometal bond resistance of the alloys tested.

Device for recording the path of insertion for removable partial dentures.

Some negative outcomes of oral rehabilitation using removable partial dentures (RPDs) can be prevented when the framework of the RPD is planned with mounted diagnostic casts that have been analyzed in a dental surveyor. Recording the established path of insertion can be difficult when the procedure uses a pin that is cemented in the cast base, and the casts are mounted in an articulator. This article presents a procedure for a pin device to record the path of insertion of RPDs. This device serves the same purpose as the cemented pin but can be easily removed and replaced.

A clinical evaluation of materials for interocclusal registration in centric relation.

Four techniques for interocclusal registrations of centric relation based on materials or combinations of materials usually utilized were tested by means of mounting of casts for a patient with partial lower edentulousness, without a free end saddle. To ensure the correct position of centric relation a Lucia jig was utilized. The following conditions for the record of posterior section were tested: registrations with wax, wax plus zinc oxide-eugenol paste, wax plus Duralay acrylic resin, and condensation silicone (putty). The evaluation was made by the measure of vertical distance between reference points in the base of the casts and calculation of variations occurring with each material. The combinations of wax plus zinc oxide-eugenol paste and wax plus Duralay acrylic resin showed the smallest variations in centric relation position.

Effect of beryllium on the castability and resistance of ceramometal bonds in nickel-chromium alloys.

STATEMENT OF PROBLEM: Castability and ceramometal bond resistance play an important role in accepting nickel-chromium alloys as a substitute for gold alloys in dentistry. PURPOSE: This study was developed to verify the effect of beryllium on these factors in several compositions of nickel-based alloys by submitting them to castability and ceramometal bonding resistance tests. MATERIAL AND METHODS: Three experimental compositions of Ni-Cr alloys with different amounts of beryllium were used. One beryllium-free alloy was used as the control. RESULTS: Analysis of variance and Tukey's test showed significant differences (alpha = .001) for the castability test results and significant differences (alpha = .05) for ceramometal bond resistance between alloys. CONCLUSIONS: Although the amounts of chromium, manganese, and niobium were maintained, the variations in the amounts of beryllium allowed the estimation that Be-containing alloys presented better castability than Be-free alloys. The 0.9% Be-containing alloy demonstrated higher resistance of the ceramometal bond than the Be-free alloy.

Maintenance of prosthetic treatment in a geriatric patient--case report.

A 76-year old female patient came to the Specialized Clinic for Long-Lasting Dentures of the Dental School of Ribeirão Preto, USP, for prosthetic treatment for the correction of the absence of several teeth. The patient's medical history and examination revealed the presence of psoriasis that had progressed to a rheumatoid arthritis-like condition causing motor deficits such as difficulty in picking up and holding a toothbrush. We proposed two acrylic removable partial dentures, with a chromium-cobalt metal support planned for the lower denture. For the maintenance of oral hygiene we proposed an acrylic resin device coupled to the toothbrush in order to increase the volume of the toothbrush, and consequently facilitate tooth brushing. This device, although simple, has permitted the patient to have a more independent and healthy life style.

Surveying removable partial dentures: the importance of guiding planes and path of insertion for stability.

STATEMENT OF PROBLEM: Although removable partial dentures are a favored option for the restoration of many situations that involve partial tooth loss, some patients are not satisfied with a removable partial denture, especially when it is not stable during mastication. A dental surveyor can be used to prevent countless problems related to the production of removable partial dentures. Many professionals working with oral rehabilitation fail to take advantage of the many uses of a surveyor in planning and designing chromium alloy and other metal removable partial denture frameworks. PURPOSE: This article uses an academic approach to describe the criteria used to determine the path and removal of a removable partial denture. A fundamental requirement for understanding the correct use of the dental surveyor is to prevent indiscriminate use of a path of insertion perpendicular to the occlusal plane, and extreme inclinations of the cast in the attempt to create undercuts on some teeth.

Immediate partial denture with a cast metal framework. A 6-year evaluation.

The use of dentures immediately after tooth removal is a common practice in dentistry especially when tooth extraction causes aesthetic problems. In the field of complete dentures, the procedure for the construction of immediate dentures permits the preparation of prostheses with the characteristics of standard dentures that can be used for a long period of time, promoting the recovery of function and aesthetic appearance without impairing patient comfort. For removable partial dentures, immediate prostheses are usually provisional for use over a short period of time while the extraction site heals. These dentures are usually made with acrylic resin and wrought wires, and in addition to compressing delicate parts of the support system, often do not provide the comfort and security needed by the patient. Immediate removable partial dentures with a metal framework are seldom used for this procedure, probably because of the difficulty in fitting the framework prior to surgery. The authors present a clinical example in which a modification of framework positioning permitted previous fitting of the framework, eliminating the possibility of lack of fit after tooth extraction, which resulted in clinical success 6 years later.