Spring and latch dynamics can act as control pathways in ultrafast systems

Ultrafast movements propelled by springs and released by latches are thought limited to energetic adjustments prior to movement, and seemingly cannot adjust once movement begins. Even so, across the tree of life, ultrafast organisms navigate dynamic environments and generate a range of movements, suggesting unrecognized capabilities for control. We develop a framework of control pathways leveraging the non-linear dynamics of spring-propelled, latch-released systems. We analytically model spring dynamics and develop reduced-parameter models of latch dynamics to quantify how they can be tuned internally or through changing external environments. Using Lagrangian mechanics, we test feedforward and feedback control implementation via spring and latch dynamics. We establish through empirically-informed modeling that ultrafast movement can be controllably varied during latch release and spring propulsion. A deeper understanding of the interconnection between multiple control pathways, and the tunability of each control pathway, in ultrafast biomechanical systems presented here has the potential to expand the capabilities of synthetic ultra-fast systems and provides a new framework to understand the behaviors of fast organisms subject to perturbations and environmental non-idealities.

Contactless skin perfusion monitoring with video cameras: tracking pharmacological vasoconstriction and vasodilation using photoplethysmographic changes

Objectives.Clinical assessment of skin perfusion informs prognosis in critically ill patients. Video camera monitoring could provide an objective, continuous method to monitor skin perfusion. In this prospective, interventional study of healthy volunteers, we tested whether video camera-derived photoplethysmography imaging and colour measurements could detect drug-induced skin perfusion changes.Approach.We monitored the lower limbs of 30 volunteers using video cameras while administering phenylephrine (a vasoconstrictor) and glyceryl trinitrate (a vasodilator). We report relative pixel intensity changes from baseline, as absolute values are sensitive to environmental factors. The primary outcome was the pre- to peak- infusion green channel amplitude change in the pulsatile PPGi waveform component. Secondary outcomes were pre-to-peak changes in the photoplethysmographic imaging waveform baseline, skin colour hue and skin colour saturation.Main results.The 30 participants had a median age of 29 years (IQR 25-34), sixteen (53%) were male. A 34.7% (p= 0.0001) mean decrease in the amplitude of the pulsatile photoplethysmographic imaging waveform occurred following phenylephrine infusion. A 30.7% (p= 0.000004) mean increase occurred following glyceryl trinitrate infusion. The photoplethysmographic imaging baseline decreased with phenylephrine by 2.1% (p= 0.000 02) and increased with glyceryl trinitrate by 0.5% (p= 0.026). Skin colour hue changed in opposite direction with phenylephrine (-0.0013,p= 0.0002) and glyceryl trinitrate (+0.0006,p= 0.019). Skin colour saturation decreased with phenylephrine by 0.0022 (p= 0.0002), with no significant change observed with glyceryl trinitrate (+0.0005,p= 0.21).Significance.Drug-induced vasoconstriction and vasodilation are associated with detectable changes in photoplethysmographic imaging waveform parameters and skin hue. Our findings suggest video cameras have great potential for continuous, contactless skin perfusion monitoring.

Oral pigmented lesions: a retrospective analysis from Brazil

Background

Pigmented lesions are uncommon in the oral mucosa, and studies investigating the incidence and types of these lesions are desired to improve the diagnostic knowledge of clinicians. The aim of this study was to analyze the distribution of oral pigmented lesions in a Brazilian population.

Material and Methods

A retrospective descriptive cross-sectional study was performed. Oral pigmented lesions were retrieved from the files of two oral and maxillofacial pathology services from Brazil over a 45-year period (1974-2019). The clinical data and the diagnoses of each case were retrieved and included in a Microsoft Excel® database.

Results

From 77.074 lesions diagnosed in this period, 761 (0.99%) represented pigmented lesions of the oral mucosa, including 351 (46.1%) melanocytic and 410 (53.9%) non-melanocytic lesions, with a higher incidence in females (73.2%) between the fourth and seventh decades of life. Amalgam tattoo (53.6%) represented the most common lesion, followed by melanotic macule (18.3%) and racial pigmentation (10.8%). Other pigmented lesions included nevus (9.9%), post-inflammatory pigmentation (3%), melanoma (2.1%), melanoacanthoma (1.4%), smoker's melanosis (0.4%), drug-induced pigmentation (0.3%), and melanotic neuroectodermal tumor of infancy (0.1%). The buccal mucosa was the most commonly affected site (25.2%), followed by the alveolar ridge (14.5%), and gingiva (11.8%).

Conclusions

The current findings were similar to previous studies with minor differences due methodology and characteristics of the services from where lesions were retrieved. The knowledge of these data may contribute to a better understanding of oral pigmented lesions and assist clinicians to better recognize and manage them.

Key words:Pigmented lesions, pigmentation, melanin, amalgam, oral cavity.

Evaluation of natural background levels of high mountain karst aquifers in complex hydrogeological settings. A Gaussian mixture model approach in the Port del Comte (SE, Pyrenees) case study

The hydrogeological processes driving the hydrochemical composition of groundwater in the alpine pristine aquifer system of the Port del Comte Massif (PCM) are characterized through the multivariate statistical techniques Principal Component Analysis (PCA) and Gaussian Mixture Models (GMM) in the framework of Compositional Data (CoDa) analysis. Also, the groundwater Natural Background Levels (NBLs) for NO₃ and SO₄ and Cl are evaluated, which are specially important for indicating the occurrence of groundwater contamination derived from the anthropic activities conducted in the PCM. The different hydrogeochemical facies found in the aquifer system of the PCM comprises low mineralized Ca-HCO₃ water for the main Eocene karst aquifer, and Ca-SO₄ and highly mineralized NaCl water types in the minor aquifers discharging from the PCM. The NBL values of SO₄, Cl and NO₃ obtained for the main karst aquifer are 14.33, 4.06 and 6.55 mg/L, respectively. These values are 35, 3 and 1.2 times lower than the respective official NBLs values that were determined by the water administration to be compared with in the case of conducting a pollution assessment characterization in the main karst aquifer. Official overestimation of NBLs can put important groundwater resources in the PCM at risk.

Snaps of a tiny amphipod push the boundary of ultrafast, repeatable movement

Surprisingly, the fastest motions are not produced by large animals or robots. Rather, small organisms or structures, including cnidarian stinging cells, fungal shooting spores, and mandible strikes of ants, termites, and spiders, hold the world acceleration records.^1-5 These diverse systems share common features: they rapidly convert potential energy - stored in deformed material or fluid - into kinetic energy when a latch is released.^4-6 However, the fastest of these are not repeatable, because mechanical components are broken or ejected.^5,6 Furthermore, some of these systems must overcome the added challenge of moving in water, where high density and viscosity constrain acceleration at small sizes. Here we report the kinematics of repeatable, ultrafast snaps by tiny marine amphipods (Dulichiella cf. appendiculata). Males use their enlarged major claw, which can exceed 30% of body mass, to snap a 1 mm-long dactyl with a diameter equivalent to a human hair (184 μm). The claw snaps closed extremely rapidly, averaging 93 μs, 17 m s^-1, and 2.4 x 10⁵ m s^-2. These snaps are among the smallest and fastest of any documented repeatable movement, and are sufficiently fast to operate in the inertial hydrodynamic regime (Reynolds number (Re) >10,000). They generate audible pops and rapid water jets, which occasionally yield cavitation, and may be used for defense. These amphipod snaps push the boundaries of acceleration and size for repeatable movements, particularly in water, and exemplify how new biomechanical insights can arise from unassuming animals. VIDEO ABSTRACT.

Comparison of the whole slide imaging and conventional light microscopy in the grading of oral epithelial dysplasia: a multi-institutional study

Background

Whole Slide Imaging (WSI) is an alternative method to light microscopy (LM). However, few studies have compared the diagnostic agreement between WSI and LM, especially to grade oral epithelial dysplasia (OED). The purpose of this study was to evaluate the variability in grading OED by the World Health Organization grading system, using WSI and conventional LM, and to investigate whether the access to clinical information, and psychologic or physical states of the pathologists could interfere with the diagnosis.

Material and Methods

eleven experienced pathologists from seven Brazilian universities independently evaluated twenty-five OED cases. The analyses were performed in duplicate for each method, with an interval of at least 30 days, and the time consumed in each analysis was measured. Physical and psychologic states were evaluated by blood pressure levels, heart rate and two questionnaires: State-Trait Anxiety Inventory and Perceived Stress Scale. Clinical information was provided after the second evaluation using WSI and the pathologist could change their diagnostic decision or not.

Results

LM showed a higher inter-examiner agreement (k=0.53) than WSI (k=0.45) and a smaller time consumed by the pathologists (mean of 65.53 seconds compared to 91.02 seconds in WSI). In the first analysis using conventional microscopy, there was a positive correlation between kappa values and anxiety (r=0.47, p=0.02), and stress (r=0.64, p<0.01), and an inverse correlation with heart rate (r=-0.48, p=0.02). In the digital analysis, there was also a positive correlation between kappa values and anxiety (r=0.75, p<0.001). After clinical information was given, there was a slight change in 11.3% of the cases, and a great discrepancy in 1.1% of the cases, mainly increasing the OED grade.

Conclusions

both microscopy systems had similar results, although LM had slightly higher kappa values, and WSI was more time consuming.

Key words:Pathology, microscopy, diagnosis, leukoplakia oral, anxiety.

Comparative expression of cyclooxygenase 2 and Ki67 in amelanotic and conventional oral melanomas

BACKGROUND

Oral melanomas have some histopathological resemblance with its cutaneous counterpart; however, an aggressive behavior is more common in tumors that occur in the oral cavity. Several markers have been suggested as indicative of tumoral progression and aggressiveness, such as cyclooxygenase 2 (COX-2) and Ki67.

MATERIAL AND METHODS

In this study, we have compared the expression of COX-2 and Ki67 in a series of amelanotic (n=7) and melanotic oral melanomas (n=22). The cases were selected from 4 pathology laboratories and submitted to the immunohistochemical (IHC) reactions. We analyzed the IHC staining based on a qualitative - using visual scores; and a computer-assisted method (quantitative) using scanned slides and software for digital analysis.

RESULTS

COX-2 was expressed in all oral melanomas; however, its intensity was significantly higher in the amelanotic ones (P<0.001). Similarly, a high Ki67-positivity index was observed in the amelanotic than melanotic ones (P<0.001).

CONCLUSIONS

Based on these results, we suggest that amelanotic oral melanomas have marked pro-inflammatory and high-proliferative phenotype, justifying their more aggressive behavior compared with the melanotic ones.

Radiographic estimation of the growth rate of initially underdiagnosed ameloblastomas

BACKGROUND

To evaluate the specific growth rate (SGR) of ameloblastoma.

MATERIAL AND METHODS

cases of ameloblastoma initially underdiagnosed (e.g. cases overlooked or diagnosed as reactive lesions) which had adequate radiographic documentation to evaluate their progression were retrospectively selected. Two panoramic radiographs were analyzed to determine the specific growth rate (SGR) of each tumor, defined as the logarithm of the ratio of final tumor area (when the diagnosis of ameloblastoma was made) to the initial tumor area (when the lesion was underdiagnosed), divided by the time interval between the radiographic images. The tumor area was measured using the software ImageJ.

RESULTS

Twelve patients with mandibular ameloblastomas were selected, including 5 males and 7 females, with a mean age of 24.9 years (range: 14-61 years). In four cases, the lesion was associated with the crown of an impacted third molar. In three cases, it was initially diagnosed as a periapical lesion. Three cases were extrafollicular and were not noticed in the initial radiographs. Two cases were initially diagnosed as ameloblastoma, but the surgery was delayed for personal reasons. The mean interval of time between the two radiographic images was 4.3 years (range: 0.4-9 years). Based on our analysis, ameloblastoma grows in average 40.4% per year (range: 14.9-88.7%).

CONCLUSIONS

Ameloblastoma is a progressively growing tumor, but its growth rate seems to be smaller than initially reported in the literature. Better understanding the radiographic progression of ameloblastoma might improve its early diagnosis, management, and prognosis.

Contribution of isotopic research techniques to characterize high-mountain-Mediterranean karst aquifers: The Port del Comte (Eastern Pyrenees) aquifer

Water resources in high mountain karst aquifers are usually characterized by high rainfall, recharge and discharge that lead to the sustainability of the downstream ecosystems. Nevertheless, these hydrological systems are vulnerable to the global change impact. The mean transit time (MTT) is a key parameter to describe the behavior of these hydrologic systems and also to assess their vulnerability. This work is focused on estimating MTT by using environmental tracers in the framework of high-mountain karst systems with a very thick unsaturated zone (USZ). To this end, it is adapted to alpine zones a methodology that combines a semi-distributed rainfall-runoff model to estimate recharge time series, and a lumped-parameter model to obtain ΜΤΤ. The methodology has been applied to the Port del Comte Massif (PCM) hydrological system (Southeastern Pyrenees, NE Spain), a karst aquifer system with an overlying 1000 m thick USZ. Six catchment areas corresponding to most important springs of the system are considered. The obtained results show that hydrologically the behavior of the system can be described by an exponential flow model (EM), with MTT ranging between 1.9 and 2.9 years. These ΜΤΤ values are shorter than those obtained by considering a constant recharge rate along time, which is the easiest and most applied aquifer recharge hypothesis when estimating ΜΤΤ through lumped-parameter models.

Central corneal thickness and anterior chamber depth measurement by Sirius(®) Scheimpflug tomography and ultrasound

Background

The purpose of this study was to compare the accuracy of the new Sirius^® Scheimpflug anterior segment examination device for measurement of central corneal thickness (CCT) and anterior chamber depth (ACD) with that of CCT measurements obtained by ultrasound pachymetry and ACD measurements obtained by ultrasound biometry, respectively.

Methods

CCT and ACD was measured in 50 right eyes from 50 healthy subjects using a Sirius Scheimpflug camera, SP100 ultrasound pachymetry, and US800 ultrasound biometry.

Results

CCT measured with the Sirius was 546 ± 39 μm and 541 ± 35 μm with SP100 ultrasound pachymetry (P = 0.003). The difference was statistically significant (mean difference 4.68 ± 10.5 μm; limits of agreement −15.8 to 25.20 μm). ACD measured with the Sirius was 2.96 ± 0.3 mm compared with 3.36 ± 0.29 mm using US800 ultrasound biometry (P < 0.001). The difference was statistically significant (mean difference −0.40 ± 0.16 mm; limits of agreement −0.72 to 0.07 mm). When the ACD values obtained using ultrasound biometry were corrected according to the values for CCT measured by ultrasound, the agreement increased significantly between both technologies for ACD measurements (mean difference 0.15 ± 0.16 mm; limits of agreement −0.16 to 0.45 mm).

Conclusion

CCT and ACD measured by Sirius and ultrasound methods showing good agreement between repeated measurements obtained in the same subjects (repeatability) with either instrument. However, CCT and ACD values, even after correcting ultrasound ACD by subtracting the CCT value obtained with either technology should not be used interchangeably.

Clinical evaluation of the IOPen® in a glaucomatous population

The aim of this study was to evaluate the level of agreement of measurements of intraocular pressure (IOP) taken by a rebound tonometer (IOPen®), in comparison to a reference Goldmann applanation tonometer (GAT) in a glaucomatous population. Both eyes from 60 patients were assessed with the two tonometers, the induction tonometry was performed first by an experienced optometrist, and the GAT by an ophthalmologist. In this study, statistically significant differences were found when comparing the IOPen® tonometer with the GAT tonometer (p < 0.001), mean differences were -4.81 ± 4.31 and -4.76 ± 5.76 mmHg (mean ± S.D.) for the right eye and left eye respectively These values represent an underestimation in the present population by the IOPen® when compared with the GAT. Frequency distribution of differences demonstrated that in more than 71.6% of the measurements the IOP readings differed by more than 3 mmHg between the two tonometers. These results suggest that IOPen® should be used with great caution in the determination of IOP.

Comparison of the IOPen and iCare rebound tonometers with the Goldmann tonometer in a normal population

This study proposes to evaluate the level of accuracy of intraocular pressure (IOP) measurements of a second generation rebound tonometer (IOPen, taking as references the Goldmann Applanation Tonometer (GAT) and the iCare rebound tonometer. The right eyes of 101 consecutive clinical patients were assessed with the three tonometers. The IOPen and iCare measurements were taken by two different optometrists and the GAT by an ophthalmologist. In this study, statistically significant differences were found when comparing the IOPen tonometer with the other two tonometers (p < 0.001). The IOPen underestimated the IOP value when compared to the GAT and the iCare (mean differences were 2.94 +/- 4.65 mmHg and 3.20 +/- 4.72 mmHg (mean +/- S.D.), respectively). The frequency distribution of differences demonstrated that in more than 55% of measurements the IOP readings differed by more than 3 mmHg between the IOPen and the GAT. Based on the present population study, these results suggest that IOPen measurements should be interpreted with caution.

Lichen sclerosus of the oral mucosa: clinicopathological features of six cases

Lichen sclerosus is a chronic inflammatory mucocutaneous disease, rarely involving the mouth. There are only 20 well-documented cases of oral lichen sclerosus reported in the English-language literature. This report describes the clinicopathological features of 6 cases of oral lichen sclerosus; 5 in women. There were 12 lesions, mainly on the lips (50%) and buccal mucosa (25%). The affected areas appeared as irregular whitish patches, harder than the surrounding tissue. Half of the patients were symptomatic and presented with no associated skin and/or genital lesions. All cases were biopsied, and histopathological features were evaluated using hematoxylin-eosin and Verhoeff's stains, S-100 immunohistochemical reaction and transmission electron microscopy. Management of the oral lesions consisted of surgical excision, intralesional triamcinolone acetonide, oral colchicine, and regular follow-up. There is no effective curative treatment, but there are some options for patient management; and colchicine may be considered an additional choice.

Influence of fogging lenses and cycloplegia on open-field automatic refraction

PURPOSE

To compare refractive values measured with and without cycloplegia, or with fogging lenses, using an open-field auto-refractor.

METHODS

One hundred and forty-two young adults were enrolled from a university population; 96 were female (67.6%) and 46 were male (32.4%), the age range was 18-26 years (mean 22.3 +/- 3.7 years). The refraction measurement was obtained for the right eye of each subject with the Grand Seiko Auto Ref/Keratometer WAM-5500 (GS) under three conditions, always in this sequence: (1) without cycloplegia (GS), (2) without cycloplegia but using a + 2.00 D fogging lens (GS_2D) and (3) with cycloplegia (GS_cycl).

RESULTS

When the average values of spherical equivalent were compared, both accommodation control strategies were almost equally successful: GS, M = -0.85 +/- 2.21 D; GC_2D, M = -0.53 +/- 2.10 D and GS_cycl, M = -0.57 +/- 2.24 D (Kruskal-Wallis test, p < 0.001). When the results were analysed separately for different refractive groups, emmetropes and hyperopes show statistically significant differences while myopes did not. When both accommodation strategies were compared there was a trend for more myopic subjects to display more negative values under cycloplegia, while low myopes, emmetropes and hyperopes tend to display more negative values with the +2.00 D fogging lenses, suggesting this was less effective for accommodation control.

CONCLUSIONS

Over-refraction through +2.00 D fogging lenses is useful to achieve additional relaxation of the accommodative response in a similar way to cycloplegia when open-field autorefraction is performed in young adults.

Efficacy of the liposome trifluralin in the treatment of experimental canine leishmaniosis

Liposomes are used as carriers to deliver drugs and to treat diseases where infection is localised in the mononuclear phagocyte system cells, as is the case of leishmaniosis. Trifluralin is a dinitroaniline with proved anti-Leishmania activity in vitro. The efficacy of liposomal trifluralin (LIP/TFL) was studied in the treatment of experimental canine leishmaniosis through quantification of parasite burden using the limiting dilution assay, follow-up of anti-Leishmania antibodies by indirect fluorescent immunoassay and cytokine expression by Reverse Transcriptase-PCR, in the bone marrow, lymph nodes, skin and peripheral blood mononuclear cells in 5 female beagle dogs. After treatment, dogs showed a general remission of clinical signs related to parasite burden reduction and Th1 cytokine mRNA expression, but there was no significant decrease in antibody levels. Alternative treatment schemes with LIP/TFL are necessary to achieve optimal results.

Subgemmal neurogenous plaque associated with burning tongue: report of two cases and review of the literature

Subgemmal neurogenous plaques, biphasic structures with a neurofibroma and neuroma patterns, are observed in tongue biopsies involving subepithelial areas, being characterized as aggregates of nerve plexus and ganglion cells. Oral burning symptoms, having many possible causes, are commonly observed during oral medicine practice, but the association of subgemmal neurogenous plaque with tongue burning symptoms is very unusual. Reported here are two cases of focal burning sensation in the lateral border of the tongue diagnosed as subgemmal neurogenous plaque through biopsy. Recognizing this entity is important to avoid misdiagnosis of other neural proliferations, especially in cases involving focal tongue burning.

Technical note: a comparison of central and peripheral intraocular pressure using rebound tonometry

PURPOSE

To compare central and peripheral intraocular pressure (IOP) readings obtained with rebound tonometry.

METHODS

Intraocular pressure was measured on the right eye of 153 patients (65 males, 88 females), aged from 21 to 85 years (mean +/- S.D., 55.5 +/- 15.2 years) with the ICare rebound tonometer at centre, and 2 mm from the limbus (in the nasal and temporal regions along the 0-180 degrees corneal meridian).

RESULTS

Intraocular pressure values obtained with the ICare were 14.9 +/- 2.8; 14.1 +/- 2.5 and 14.5 +/- 2.7 mmHg at centre, nasal and temporal corneal locations, respectively. On average, nasal and temporal IOP readings were 0.75 and 0.37 mmHg lower than the central reading (p < 0.05 and p > 0.05, respectively). A highly significant correlation was found between central and peripheral measurements in nasal (r(2) = 0.905; p < 0.001) and temporal (r(2) = 0.879; p < 0.001) regions along the horizontal meridian. Almost 80% of patients presented nasal IOP values within +/-1 mmHg of the central value.

CONCLUSIONS

Intraocular pressure values measured with the ICare rebound tonometer on the nasal corneal region is slightly lower on average and highly correlated with IOP values recorded at corneal centre. Both nasal and temporal readings are in good agreement with central IOP, and could be used to obtain a reliable estimate of rebound IOP in corneas where central readings cannot be taken.

Refractive, biometric and topographic changes among Portuguese university science students: a 3-year longitudinal study

PURPOSE

The aim of this study was to investigate the changes in refractive, biometric and topographic ocular parameters among university students in Portugal during a 3-year period.

METHODS

A 3-year longitudinal study comprised 118 Portuguese university students from the School of Science (34 males and 84 females; mean age 20.6 +/- 2.3 years). Ocular refraction, corneal curvature (CR) and eccentricity, and A-scan biometry were conducted under cycloplegia. The sphero-cylindrical refractive results were converted into vector representations (M, J(0) and J(45)) for statistical analysis. Myopia was defined as M < or = -0.50 D, emmetropia as M > -0.50 D and < +0.50 D and hyperopia as M > or = +0.50 D.

RESULTS

At the beginning of the study sphero-cylindrical refraction (M) ranged from -6.75 to +3.00 D, with a mean value of 0.23 +/- 1.46 D [mean +/- standard deviation (S.D.)]. Eighty-three students presented astigmatism with a mean value (+/-S.D.) of -0.52 +/- 0.41 D, and a maximum of -2.25 D. After 3 years the mean refractive change for the M component was -0.29 +/- 0.38 D (p < 0.001) and non-significant changes of 0.02 +/- 0.16 D (p = 0.281) for the J(0) component and 0.01 +/- 0.09 D (p = 0.784) for the J(45) component. Prevalence of myopia increased by 5.1%, while the prevalence of hyperopia decreased by 9.4%. Myopia progression > or =0.5 D was observed in 22% of the population. Axial length, vitreous chamber depth and lens thickness increased significantly while anterior chamber depth and central CR did not change significantly.

CONCLUSIONS

This study shows a change in refraction towards myopia accompanied by a vitreous chamber elongation in a Portuguese population comprising science students during the first three years of their university course. Younger students were more likely to show clinically significant myopia progression.

Characterization of inflammatory cells in oral paracoccidioidomycosis

Paracoccidioidomycosis (Pmycosis) is one of the most common deep mycoses in many regions of Latin America, particularly in Brazil. Microscopically, it shows granulomatous inflammatory reaction with giant cells, macrophages, lymphocytes, plasma cells, polymorphonuclear neutrophilic leukocytes, and eosinophils. The purpose of this study was to assess the distribution of inflammatory cells in oral Pmycosis. Fifteen cases of oral Pmycosis were studied by immunohistochemistry for the presence of macrophages, CD4(+) and CD8(+) lymphocytes, CD20(+), CD15(+), and S100(+) cells. Macrophages were the main cells in well-organized granulomas and non-granulomatous areas. The CD4 phenotype was predominant in well-organized granulomas and a balance between CD4(+) and CD8(+) cells was observed in non-granulomatous areas. Dendritic, S100(+) cells were found mainly in the epithelium, in subepithelial connective tissue, and at the periphery of organized granulomas. CD15(+) cells were concentrated mainly in areas of intraepithelial microabscess and ulceration. Macrophages and T cells are the predominant cells in oral Pmycosis. Well-organized granulomas contain fewer yeast particles, indicating a more effective host immune response. Better understanding of the histopathological changes in oral Pmycosis might help determine treatment, severity and systemic involvement of the disease.

Technical Note: Accuracy and repeatability of a new portable ultrasound pachymeter

PURPOSE

To assess the accuracy and repeatability of central corneal thickness (CCT) measurements taken with a new portable ultrasound (US) pachymeter.

METHODS

Central thickness measurements were taken with a portable pachymeter (SP-100 Handy; Tomey, Nagoya, Japan) and a conventional US pachymeter (Nidek UP-1000; Nidek Technologies, Gamagori, Japan) from 57 right corneas of 57 young adults (19 males, 38 females) aged 18-44 years (mean +/- S.D., 22.95 +/- 3.92). Three repeated measures were obtained and then compared to obtain the repeatability of each instrument and the agreement between the pachymeters. The three readings taken with the portable pachymeter were compared against each other in order to evaluate intra-session repeatability and bias of each individual measurement with respect to the mean of three.

RESULTS

Mean values of CCT were 537 +/- 35 microm for conventional and 534 +/- 35 microm for the new portable pachymeter. A high agreement was found between the two instruments (mean difference = 2.58 microm; 95% CI 1.41-3.75 microm) with only two eyes presenting differences larger than +/-8.6 microm which represents 95% CI in the Bland-Altman plots which represents 1.6% of the mean CCT. The first reading taken showed the highest agreement with the mean value for the portable pachymeter.

CONCLUSIONS

The instrument tested in this study is able to take reliable measurements of corneal thickness even if a single reading is considered. Intra-session repeatability was very high, as was also the agreement between the average of three readings taken with the two US pachymeters.

Age differences in central and peripheral intraocular pressure using a rebound tonometer

AIM

To evaluate the influence of age on the measurements and relationships among central and peripheral intraocular pressure (IOP) readings taken with a rebound tonometer.

METHODS

The IOPs were measured using the ICare rebound tonometer on the right eyes of 217 patients (88 men and 129 women) aged 18-85 years (mean 45.9 (SD 19.8) years), at the centre and at 2 mm from the nasal and temporal limbus along the horizontal meridian. Three age groups were established: young (< or =30 years old; n = 75), middle aged (31-60 years old; n = 77) and old patients (>60 years old; n = 65).

RESULTS

A high correlation was found between the central and peripheral IOP readings, with the central readings being higher than the peripheral ones. Higher IOP values for the central location were found in the younger patients. Older patients had significantly lower temporal IOP readings than those for the remaining two groups (p<0.001), whereas no significant differences were found among groups when IOP was measured at the central and nasal locations. A significant decrease was observed in the nasal and temporal IOP readings as the age increased (p = 0.011 and 0.006, respectively).

CONCLUSION

Older patients had lower IOP values than the middle-aged and younger patients in the temporal peripheral location. A negative correlation was found between age and IOP by rebound tonometry in the corneal periphery but not in its centre.

Non-contact tonometry synchronized with cardiac rhythm and its relationship with blood pressure

PURPOSE

The main objectives of this study were to determine the differences between non-synchronized intraocular pressure (IOP_N) and intraocular pressure readings synchronized with cardiac pulse and try to determine if these parameters are related to blood pressure values.

METHODS

One hundred and sixty-five right eyes from 165 volunteers (107 females, 58 males) aged from 19 to 73 years (mean +/- S.D., 29.93 +/- 11.17) were examined with the Nidek NT-4000, a new non-contact tonometer that allows the measurement of IOP synchronized with the cardiac rhythm. IOP measurements in the four different modes of synchronization were taken in a randomized order. Three measures of each parameter were taken and then averaged. The blood pressure was determined three times with a portable manometer and mean values of systolic and diastolic pressure and the pulse rate were computed. Mean arterial pressure (MAP) was determined as being 1/3 of systolic plus 2/3 of diastolic blood pressure.

RESULTS

The mean +/- S.D. values for the standard intraocular pressure (IOP_N: 14.76 +/- 2.86), intraocular pressure in the systolic instant or peak (IOP_P: 14.99 +/- 2.85), intraocular pressure in the middle instant between heartbeats or middle (IOP_M: 14.68 +/- 2.76), and intraocular pressure in the diastolic instant or bottom (IOP_B: 13.86 +/- 2.61) were obtained. The IOP_P was higher than the remaining values. A significant difference in mean IOP existed between IOP_B and the remaining modes of measuring (p < 0.05). Differences were statistically significant for all pair comparisons involving IOP_B. Arterial blood pressure values were systolic 125.5 +/- 14.22, diastolic 77.7 +/- 8.38 and MAP 93.64 +/- 9.44 mmHg. The pulse rate was 77.3 +/- 12.6 beats per minute. Except for the MAP (p = 0.025) there was no significant correlation between different IOP values and systolic or diastolic blood pressure, or pulse rate.

CONCLUSIONS

NT-4000 is able to differentiate IOP values when synchronized with the cardiac rhythm and those differences are expected to be within a range of +/-2.5 to +/- 3.0 mmHg. IOP_B seems to be the parameter whose value differs from the non-synchronized and the remaining synchronized parameters in a significant way. Other than a weak association with MAP, no significant correlation between IOP and BP was found. The measurements of IOP readings for the three modes are consistent with timings during the cardiac cycle and IOP pulse cycle.

The influence of cycloplegia in objective refraction

The purpose of this study was to compare refractions measured with an autorefractor and by retinoscopy with and without cycloplegia. The objective refractions were performed in 199 right eyes from 199 healthy young adults with a mean age of 21.6 +/- 2.66 years. The measurements were performed first without cycloplegia and repeated 30 min later with cycloplegia. Data were analysed using Fourier decomposition of the power profile. More negative values of component M and J(0) were given by non-cycloplegic autorefraction compared with cycloplegic autorefraction (p < 0.0001). However more positive values for the J(45) vector were given by non-cycloplegic autorefraction, although this difference was not statistically significant (p = 0.233). By retinoscopy, more negative values of component M were obtained with non-cycloplegic retinoscopy (p < 0.0001); for the cylindrical vectors J(0) and J(45) the retinoscopy without cycloplegia yields more negative values (p = 0.234; p = 0.112, respectively). Accepting that differences between cycloplegic and non-cycloplegic retinoscopy are only due to the accommodative response, the present results confirm that when performed by an experienced clinician, retinoscopy is a more reliable method to obtain the objective starting point for refraction under non-cycloplegic conditions.

Comparison of the ICareR rebound tonometer with the Goldmann tonometer in a normal population

The aim of this study was to evaluate the accuracy of measurement of intraocular pressure (IOP) using a new induction/impact rebound tonometer (ICare) in comparison with the Goldmann applanation tonometer (AT). The left eyes of 46 university students were assessed with the two tonometers, with induction tonometry being performed first. The ICare was handled by an optometrist and the Goldmann tonometer by an ophthalmologist. In this study, statistically significant differences were found when comparing the ICare rebound tonometer with applanation tonometry (AT) (p < 0.05). The mean difference between the two tonometers was 1.34 +/- 2.03 mmHg (mean +/- S.D.) and the 95% limits of agreement were +/-3.98 mmHg. A frequency distribution of the differences demonstrated that in more than 80% of cases the IOP readings differed by <3 mmHg between the ICare and the AT. In the present population the ICare overestimates the IOP value by 1.34 mmHg on average when compared with Goldmann tonometer. Nevertheless, the ICare tonometer may be helpful as a screening tool when Goldmann applanation tonometry is not applicable or not recommended, as it is able to estimate IOP within a range of +/-3.00 mmHg in more than 80% of the population.

Primary intraosseous fibrosarcoma of jaw

This paper reports one case of primary fibrosarcoma affecting the mandible in a 41-year-old woman. Microscopically, the tumor was cellularized with an intense mitotic activity, and areas of necrosis and hemorrhage, and the cells showed immunoreactivity only for vimentin, establishing the diagnosis of primary intraosseous fibrosarcoma. The patient underwent tumor surgical resection, supraomohyoid neck dissection and mandible reconstruction with fibula flap and titanium bar. She also received post-surgical radiotherapy and is in follow up for 36 months without signs of recurrence or metastases.

Peutz-Jeghers syndrome in a 14-year-old boy: case report and review of the literature

Peutz-Jeghers syndrome (PSJ) is a relatively rare but well-recognized condition, with a prevalence of approximately one in 120,000 births in the USA. It is generally inherited as an autosomal dominant trait, although 35% of cases are new mutations. This disorder is characterized by melanocytic macules on the hands, feet, peri-oral skin and oral mucosa, and multiple gastrointestinal hamartomatous polyps. People with PSJ have an increased risk for developing a variety of malignant tumours. The aim of the present study was to report one case of PSJ in a 14-year-old boy with mucocutaneous pigmentation associated with duodenal hamartomatous polyps.

Ovariectomy reduces the gelatinolytic activity and expression of matrix metalloproteinases and collagen in rat molar extraction wounds

Osteoporosis is commonly associated with estrogen deficiency. However, the mechanisms by which the lack of this hormone causes bone loss are poorly understood. The bone structure of the oral cavity seems to be affected by estrogen deficiency, since a delayed healing process after tooth extraction has been observed after ovariectomy in rats. The aim of this study was to describe the effect of the absence of estrogen on the expression and activity of matrix metalloproteinases (MMC)-2 and -9 and expression of types I and III collagens in the alveolar granulation tissue of young female rats after tooth extraction. Sixty-six, four-week-old female rats underwent bilateral ovariectomies (OVX) or sham operations. Three weeks later, both first and second mandibular molars were extracted and the animals were killed by cervical dislocation 3, 5, or 7 days after tooth extraction. The granulation tissues were collected from the extracted alveolar sockets and used for zymographic, Western blot, or reverse transcription polymerase chain reaction (RT-PCR) analysis. There was a gradual increase on the expression of all studied proteins as well as MMP-2 and -9 activities in the periods after surgery. In contrast, OVX animals showed a significant decrease in the gelatinolytic activities and expression of MMP-2 and -9 and types I and III collagens. The results presented here in suggest that the absence of estrogen may possibly contribute to the delayed alveolar wound healing by interfering with the extracellular matrix turnover.

Primary tuberculosis of the oral cavity

Tuberculosis is one of the major causes of ill health and death worldwide. Nevertheless, tuberculous lesions of the oral cavity are rare and can be a diagnostic challenge, particularly in young immunocompetent patients. Most of the cases are secondary to pulmonary disease and the primary form is uncommon. In this paper, we present a case of primary oral tuberculosis, affecting the floor of mouth in a 13-year-old Brazilian male patient.

A comparison of the ARK-700A autokeratometer and Medmont E300 corneal topographer when measuring peripheral corneal curvature

PURPOSE

The purpose of this study was to evaluate if corneal topogometry measurements as taken with the ARK-700A autokeratometer are comparable with those measured by the Medmont E300 videokeratoscope at corresponding locations.

METHODS

Central and peripheral radius and eccentricity were measured in 122 right eyes of young normal subjects using autokeratometry and videokeratoscopy, obtained in a random order.

RESULTS

Curvature measurements obtained with the ARK700A and Medmont E300 correlated well for the central cornea. Larger differences were observed between peripheral autokeratometry readings and the empirically determined corresponding locations with the videokeratoscope. Correlations between the instruments are inconsistent, resulting in unacceptable confidence intervals. Corneal eccentricity was significantly different between the instruments for the vertical (t = 2.4; p = 0.018) and for the horizontal meridians. In the first case, the difference between the averaged values was not clinically significant, but in the horizontal meridian the AK significantly overestimated eccentricity values (t = -11.5; p < 0.001) with differences which were clinically significant.

CONCLUSIONS

Central corneal curvature data obtained by ARK700A and Medmont E300 can be interchanged but the same is not true of peripheral determinations of corneal shape. ARK700A probably measures peripheral corneal shape within an elliptical region between 5 and 7 mm in diameter, with the major axis in the vertical meridian.

Oral Candida flora from Brazilian human immunodeficiency virus-infected patients in the highly active antiretroviral therapy era

One of the main opportunistic fungal infections amongst immunocompromised individuals is oral candidosis, which has been found in up to 90% of human immunodeficiency virus (HIV)-infected patients. This study employed yeasts isolated from the saliva and oral cavities of 114 HIV-infected patients living in Campinas, São Paulo. Of the isolates, 57.8% were identified as Candida albicans and 42.1% as non-C. albicans. The latter isolates were subsequently identified as C. krusei (7.5%), C. lusitaniae (5.2%), C. tropicalis (4.6%), C. parapsilosis (4.6%), C. glabrata (2.8%), C. kefyr (1.7%), C. guilliermondii (1.7%), C. intermedia (1.1%), C. norvegensis (0.5%), and Rhodotorula rubra (1.7%). Susceptibility of the isolates to amphotericin B, fluconazole, miconazole, and itraconazole was also determined by a microdilution method adopted by the National Committee for Clinical Laboratory Standards. The isolates demonstrated various susceptibilities to the antifungal agents. In particular 29 C. albicans and 13 non-C. albicans isolates showed low susceptibility to FLCZ (> 64 micro g/ml). This study revealed huge diversity of Candida species, in particular the increasing emergence of non-C. albicans associated with the oral flora of HIV-infected patients.

Clinical performance of non-contact tonometry by Reichert AT550 in glaucomatous patients

Measuring intraocular pressure (IOP) by non-contact tonometry (NCT) has been demonstrated to be a valid and reliable technique to be used in primary eye care; it is easier to use, it does not transmit infectious diseases, and it is not necessary to use anaesthetic or staining eye drops. Recently, a new NCT device has showed an excellent level of agreement with Goldmann tonometry, but there are no records of its performance in glaucomatous eyes. To rectify this, IOP was measured in twenty-two patients (44 eyes) receiving medical treatment to control elevated IOP, with AT550 and Goldmann tonometry. Mean values of IOP were 18.98 +/- 2.77 and 19.08 +/- 3.02 mmHg using Goldmann and AT550, respectively. Plots of differences against means displayed good agreement (mean difference +/- limits of agreement, -0.09 +/- 3.30); this value was not significantly different from zero (t-test for dependent samples, p = 0.709). In conclusion, IOP values as measured with the AT550 NCT are clinically comparable with those obtained with Goldmann tonometry in glaucomatous patients. This validates this NCT not only for screening of IOP but to follow-up glaucomatous patients with a rapid, non-invasive method.

Primary aspergillosis affecting the tongue of a leukemic patient

We describe a case of primary aspergillosis involving the tongue of a patient with acute myeloid leukemia. Intraoral aspergillosis is very rare and we found only 23 cases reported in the English literature. Clinically it was a 2-cm, ulcerated, grayish lesion on the dorsum of the tongue. Microscopically there was invasion of the epithelium, connective tissue and muscle of the tongue by fungal hyphae branching at 45 degrees angle. The large hyphae were easily seen by H & E stain, and were strongly positive for periodic acid-Schiff and Grocott methenamine. The patient was successfully treated with intravenous amphotericin B. Based on clinical, microscopic and culture data, the diagnosis of primary aspergillosis of the tongue was established. Invasive oral aspergillosis is a potentially lethal disease and it should be considered in immunosuppressed patients.

Transmission of HIV in the dental clinic and elsewhere

This review focuses on the risk of transmission of HIV in dental practice in developed and developing countries; and as a result of oral sex, perinatal transmission and breast feeding. Postexposure prophylaxis (PEP) and practical measures to control cross-infection with TB are also discussed. There are few data from resource-poor countries where prevalence of HIV and risk of infection are higher--issues that deserve priority. Available information indicates that the risk of HIV transmission in the dental office is very low. Transmission of HIV from three healthcare workers to patients has been confirmed, including a dentist who infected six patients. There are >300 reports (102 confirmed) of occupational transmission to healthcare workers, including nine dental workers (unconfirmed). Exposure to HIV has been reported by 0.5% dentists/year. The risk of HIV infection after percutaneous exposure (0.3%) can be reduced by 81% with zidovudine PEP. However, risk assessment is required to assess the need and appropriate regimen. The risk of HIV transmission associated with orogenital sex exists, but is considered extremely low: barrier protection is recommended. Conversely, the proportion of babies who acquire HIV from untreated HIV-seropositive mothers is 15-25% in developed countries and 25-45% in developing countries. The frequency of HIV transmission attributable to breastfeeding is 16%. Airborne transmission of TB can be avoided by the prompt referral of known/suspected cases of active TB for chemotherapy, deferral of elective procedures until patients are not infectious, and the use of appropriate standard/isolation precautions including adequate ventilation of treatment areas.

Clinical performance of the Reichert AT550: a new non-contact tonometer

The aim of the present study was to assess the level of accuracy for measurements of intra-ocular pressure (IOP) obtained with a new non-contact tonometer (NCT) the Reichert AT550. Measurements were compared against those obtained with the Reichert Xpert Plus, Goldmann applanation tonometer and Perkins tonometer. Thirty-five university students were assessed with the four tonometers in a randomised order, with non-contact tonometry performed first. Each of the four measurement devices had its own trained clinical observer. Plots of differences of IOP as a function of the mean for each pair of instruments were obtained. No statistically significant differences were found when comparing the AT550 NCT with contact applanation tonometry (AT) (p> 0.05), displaying the closest level of agreement (as represented by the lowest mean difference and the narrowest confidence interval) with the Goldmann tonometer (limits of agreement, 0.12+/-2.17). In conclusion, readings of IOP with the AT550 NCT are clinically comparable with those obtained with Goldmann tonometry in a population with IOP within the normal range.

Thalidomide: a role in oral oncology?

Thalidomide is having increasing application in the management of a wide spectrum of immunologically-mediated and infectious disorders. It is also suggested that this agent may also have be of importance in the treatment of solid and non-solid malignancies. The present article reviews the role of thalidomide in the management of malignancy and outlines its possible potential in the treatment of malignancy of the mouth.

Juvenile intraoral pleomorphic adenoma: report of five cases and review of the literature

The aim of this study is to report on five cases of intraoral pleomorphic adenoma (PA) in patients under 18 years of age and to review the literature. Intraoral salivary gland tumours were reviewed in two Brazilian institutions and five cases of PA in patients under 18 years of age were found. Clinical data were obtained from the medical records and paraffin-embedded tissues were sectioned for proliferating cell nuclear antigen (PCNA) and p53 immunohistochemical analysis. Four patients were female and one was male; two cases affected the palate, two the upper lip and one the tongue. All five patients were treated surgically and after long follow-up periods no recurrences were observed. Tumour cells were weakly positive for PCNA and negative for p53. PA should be considered in the differential diagnosis of submucosal nodules in young patients. In youngsters, PA seems to have similar biological characteristics as in adults, with low recurrence rates after surgical resection.

Molecular characterization of Candida spp. isolated from the oral cavities of patients from diverse clinical settings

Infections by Candida spp. have increased in medical importance over the past few decades. Our understanding of species identification, commensalisms, pathogenicity, person-to-person spread, and the development of antifungal resistance within specific strains has been greatly enhanced by the utilization of molecular epidemiological methodology. The aim of the current research was to assess the quantity, species and molecular characterization of oral yeast isolates from well-defined cohorts of immunocompetent patients from a diverse range of clinical settings. Oral rinse samples were assessed for the growth of yeast and degree of colonization. Isolates were defined to the species level by both phenotypic and molecular methods and strains were further genotypically subtyped. Significant variation was shown to exist in the number, species and genotypic subgroups of yeast isolated from the oral cavity in different patient groups. This variation could be attributed to the local oral conditions unique to these patient groups.

The effect of cyclosporin A on the activity of matrix metalloproteinases during the healing of rat molar extraction wounds

Cyclosporin A (CyA) is a cyclic peptide used as an immunosuppressive agent because it can block the synthesis of interleukin-2 and other cytokines produced by CD4+ lymphocytes. It is widely used for the prevention of allograft rejection and treatment of autoimmune diseases. Several side-effects of CyA treatment have been reported, among which are chronic nephrotoxicity, hepatotoxicity and neurotoxicity, lymphoproliferative neoplasms, hypertension, thromboembolic complications and gingival overgrowth. Here, using a rat molar model, it is demonstrated that CyA immunosuppression inhibits the activity of matrix metalloproteinases 2 and 9 in the early phase of granulation tissue in the healing dental socket. These observations suggest that CyA may interfere with the wound healing following dental extractions.

Regional odontodysplasia. Report of two cases

Two cases of regional odontodysplasia in girls are reported; one affected the lower incisors, and the other the left maxilla. The first case was radiographically followed over a 6-year period, during which time the ghost teeth exhibited significant dentin formation, along with a resultant decrease in pulp size and relative normalization of the radicular anatomy. The second case involved the deciduous molars and the first permanent molar. In addition to tooth alterations, both cases exhibited many odontogenic epithelial islands and extensive areas of calcification in the mucosa. Diagnosis, causes, and treatment are discussed in the light of recent data.

Knowledge of and attitudes about blood-borne viruses and infection control in Brazilian dental practice

OBJECTIVE

To determine whether there were any recent changes in hepatitis B immunisation of dental staff, infection control or understanding of viral infections in Brazilian dentists.

DESIGN

A randomised survey was conducted on 740 dentists attending the National Dental Congress in Sao Paulo, Brazil in 1994.

SUBJECTS AND METHODS

The 740 dentists were questioned as to the presence of various viruses in saliva, the perceived risks of dental staff and long-term sequelae, the availability and uptake of vaccines, willingness to treat virus-infected persons, and means of infection control. Nearly 69% of respondents were female dentists, of mean age 30 years. Results were compared with a similar survey from 1990.

RESULTS

Most respondents knew that HIV and hepatitis viruses could appear in saliva and almost all knew of infective risks from hepatitis B (HBV), and the availability of the vaccine. Less than half knew of the association of HBV with liver cancer. There was a four-fold increase in those vaccinated against HBV since the low figure of 9% in 1990. Nearly two-thirds of respondents perceived an occupational risk to dental staff from HIV, and a similar proportion were also unwilling to treat virus-infected persons. A similar proportion also used chemical disinfection for some dental instruments.

CONCLUSIONS

The results show little improvement over a 4-year period except a much greater proportion of dentists were immunised against HBV. However, still only one third of dentists had been vaccinated, in a country with a high prevalence of infection in the general population.