Densitometry Measurements Research Articles

Analysis of corneal topographic and densitometric properties in patients receiving systemic isotretinoin therapy

Purpose To evaluate dry eye parameters, corneal topographic features, corneal densitometric changes, and anterior segment parameters in patients receiving systemic isotretinoin treatment. Methods This prospective cross-sectional study included 66 eyes of 33 patients who were started on oral isotretinoin therapy for severe acne vulgaris. All patients were evaluated in terms of ocular surface tests such as tear break-up time (TBUT) and Schirmer-1 and were asked to fill in the ocular surface disease index (OSDI) questionnaire. Corneal densitometric and topographic measurements were obtained using the Scheimpflug imaging system. Results The mean age of the patients was 19.9 ± 1.6 years, and 21 (63.6%) of the participants were female. The mean OSDI score was significantly higher in the third month than before treatment (20.05 ± 19.38, vs. 26.96 ± 22.94, p = 0.00, respectively). The mean values of the TBUT test were significantly lower in the third month than before treatment (9.06 ± 4.40 sec, vs. 10.71 ± 4.61 sec, p = 0.02, respectively). Mean scores of the Schirmer 1 test showed no statistically significant difference between before treatment and the third month (16.08 ± 8.40 mm, vs. 16.08 ± 8.50 mm, p = 1, respectively). There was no statistically significant difference between before treatment and the third month in the majority of the densitometry measurements in concentric zones. However, the difference tended to be significant between the groups concerning posterior zone 0–2 mm (11.01 ± 0.85 GSU vs. 10.62 ± 0.89 GSU, p = 0.006). The RMS LOAs (front), RMS Total (Total), RMS LOAs Total (Total), RMS HOAs Total (Total), K max, CCT, and CoV values were significantly higher in the third month than before treatment (p < 0.05 for all). Conclusions The dermatology specialists should be aware of the ocular complications of systemic isotretinoin therapy. Therefore, a complete ophthalmologic examination for the prompt apprehension and management of ocular involvement is essential in patients under isotretinoin therapy to increase ocular comfort and adherence to the therapy.

Evaluation of corneal and lens densitometry with Pentacam HR in children with Nephrotic Syndrome: A controlled, prospective study

BackgroundThis study aimed to compare the corneal and lens densitometry values between children with Nephrotic Syndrome (NS) and healthy individuals. MethodsThis cross-sectional comparative study included 23 patients with NS and 26 healthy controls. Corneal topographic and corneal and lens densitometric values were measured using Pentacam HR. Densitometry measurements in different layers were analyzed and compared between groups. Correlations between steroid cumulative dose, age at diagnosis of the disease, duration of disease, number of relapses, and patients' densitometries values were evaluated. ResultsThe measurements of the keratometry, horizontal white-to-white, and iridocorneal angle values were significantly different between groups (p < 0.05). The 0–2 mm and 2–6 mm anterior corneal densitometry values were significantly higher in NS patients. (p = 0.009 and p = 0.033, respectively). The lens densitometry values of all zones were higher in the eyes with NS but there was no statistically significant difference from the healthy control eyes (p > 0.05). There was a positive strong correlation between the cumulative steroid dose and the posterior lens zone densitometry, a positive weak correlation between the number of attacks and anterior corneal densitometry, and between disease duration and central corneal densitometry and average lens density. ConclusionIn eyes with NS, changes occur in corneal and lens densitometry in correlation with disease duration, number of attacks, and cumulative steroid dose. Significant density changes were detected especially in the anterior cornea and central 0–6 mm area.

Quality of Life in osteoporotic patients.

Osteoporosis is responsible for fragility fractures, which are associated with impaired quality of life (QoL) and disability. The aim of the study was to evaluate the QoL in patients affected by osteoporosis and possible determinants. One-hundred thirty-four subjects followed at the osteoprosis outpatient clinic at our institution completed the QUALEFFO-41 questionnaire for quality of life. All subjects had undergone bone densitometry measurement and the FRAX index, summarizing the risk of fragility fracture, was calculated for each of them. The QoL in these subjects and its possible determinants were investigated with univariate and multiple linear regression analysis. Subjects with osteoporosis had lower scores in the domains of physical and social function of the QUALEFFO questionnaire in comparison with subjects with normal bome mineral density. Main factors associated with impairment in QoL were high FRAX score and body mass index (BMI). Physical and social function is reduced in osteoporotic subjects. High BMI and an increased risk of fragility fracture were main determinants of impairment in the QoL in this study.

Long-term Effects of Uncomplicated Traumatic Hyphema on Corneal and Lenticular Clarity.

To evaluate the long-term effects of uncomplicated traumatic hyphema on endothelial morphology, anterior segment structure, and corneal and lenticular densitometry. In this retrospective comparative study, eyes with a history of uncomplicated traumatic hyphema were compared with the healthy contralateral unaffected eyes. The corneal endothelial cell properties were captured using specular microscopy. Anterior segment analysis, corneal densitometry (12-mm corneal diameter), and lens densitometry measurements were performed using the Pentacam imaging system. Measurements were obtained at a mean follow-up of 49.5 ± 15.8 months after injury. The average endothelial cell density was significantly lower in the study group than in the control group (2,506.6 ± 294.0 cells/mm² vs. 2,665.7 ± 195.0 cells/mm², p = 0.020). There was no difference between the groups in respect of polymegathism and pleomorphism (p = 0.061 and p = 0.558, respectively). All the investigated corneal tomographic and angle parameters were similar in both groups (all p > 0.05). The corneal densitometry values in all concentric zones and layers showed no statistically significant difference between the groups (p > 0.05 for all). The lens zone 1 densitometry value was significantly higher in the study group than in the control group (9.6% ± 1.1% vs. 8.9% ± 1.2%, p = 0.031). No difference was observed in zone 2 and 3 (p = 0.170 and p = 0.322, respectively). The degree of hyphema was not correlated with endothelial cell and lenticular clarity loss (p = 0.087 and p = 0.294, respectively). Even if traumatic hyphema is not complicated, long-term outcomes indicate endothelial cell loss and increased lenticular density.

Loss of Corneal Nerves and Corneal Haze in Patients with Fuchs’ Endothelial Corneal Dystrophy with the Transcription Factor 4 Gene Trinucleotide Repeat Expansion

ObjectiveSeventy percent of Fuchs’ endothelial corneal dystrophy (FECD) cases are caused by an intronic trinucleotide repeat expansion in the transcription factor 4 gene (TCF4). The objective of this study was to characterize the corneal subbasal nerve plexus and corneal haze in patients with FECD with (RE+) and without the trinucleotide repeat expansion (RE−) and to assess the correlation of these parameters with disease severity.DesignCross-sectional, single-center study.ParticipantsFifty-two eyes of 29 subjects with a modified Krachmer grade of FECD severity from 1 to 6 were included in the study. Fifteen of the 29 subjects carried an expanded TCF4 allele length of ≥ 40 cytosine-thymine-guanine repeats (RE+).Main Outcomes MeasuresIn vivo confocal microscopy assessments of corneal nerve fiber length (CNFL), corneal nerve branch density, corneal nerve fiber density (CNFD), and anterior corneal stromal backscatter (haze); Scheimpflug tomography densitometry measurements of haze in anterior, central, and posterior corneal layers.ResultsUsing confocal microscopy, we detected a negative correlation between FECD severity and both CNFL and CNFD in the eyes of RE+ subjects (Spearman ρ = −0.45, P = 0.029 and ρ = −0.62, P = 0.0015, respectively) but not in the eyes of RE− subjects. Additionally, CNFD negatively correlated with the repeat length of the expanded allele in the RE+ subjects (Spearman ρ = −0.42, P = 0.038). We found a positive correlation between anterior stromal backscatter and severity in both the RE+ and RE− groups (ρ = 0.60, P = 0.0023 and ρ = 0.44, P = 0.024, respectively). The anterior, central, and posterior Scheimpflug densitometry measurements also positively correlated with severity in both the RE+ and RE− groups (P = 5.5 × 10−5, 2.5 × 10−4, and 2.9 × 10−4, respectively, after adjusting for the expansion status in a pooled analysis. However, for patients with severe FECD (Krachmer grades 5 and 6), the posterior densitometry measurements were higher in the RE+ group than in the RE− group (P < 0.05).ConclusionsLoss of corneal nerves in FECD supports the classification of the TCF4 trinucleotide repeat expansion disorder as a neurodegenerative disease. Haze in the anterior, central, and posterior cornea correlate with severity, irrespective of the genotype. Quantitative assessments of corneal nerves and corneal haze may be useful to gauge and monitor FECD disease severity in RE+ patients.

Partial Volumes of Phosphatidylcholines and Vitamin E: α-Tocopherol Prefers Disordered Membranes.

Despite its discovery over 95 years ago, the biological and nutritional roles of vitamin E remain subjects of much controversy. Though it is known to possess antioxidant properties, recent assertions have implied that vitamin E may not be limited to this function in living systems. Through densitometry measurements and small-angle X-ray scattering we observe favorable interactions between α-tocopherol and unsaturated phospholipids, with more favorable interactions correlating to an increase in lipid chain unsaturation. Our data provide evidence that vitamin E may preferentially associate with oxygen sensitive lipids─an association that is considered innate for a viable membrane antioxidant.

Evaluation of Bone Mineral Densitometry Measurements in Newly Diagnosed Acromegaly Patients

Evaluation of Bone Mineral Densitometry Measurements in Newly Diagnosed Acromegaly Patients

Evaluation of the corneal morphologic and topographic alterations in patients with Bell’s palsy

Purpose: To evaluate the effects of ocular surface changes that may develop due to Bell’s palsy (BP) on dry eye parameters, corneal densitometry values, and aberrations in patients with unilateral BP and compare them with sound eyes.&#x0D; Materials and Methods: A total of 33 eyes of 33 patients diagnosed with unilateral BP and 33 sound fellow eyes of the patients were enrolled in this study. A complete ophthalmologic examination including best-corrected visual acuity (BCVA), intraocular pressure measurement, slit-lamp biomicroscopy to observe superficial punctate keratopathy (SPK), tear break-up time (TBUT) test, and detailed fundoscopic examination was performed for all patients. The corneal topographic, densitometric, and aberrometric measurements were performed using the Pentacam Scheimpflug imaging system.&#x0D; Results: The mean age of 33 patients was 54.9±14.7 years of whom 19 (57.6%) were female; 14 (42.4%) were male. According to the House-Brackmann scale, the majority of the patients had grade II facial nerve palsy. The BCVA in the affected eye was lower and 0.74±0.23 compared to 0.87±0.21 in sound eyes (p=0.029). The mean TBUT was lower and 6.0±4.7 in eyes affected by BP compared to 8.7±4.0 in sound eyes (p=0.014). The SPK was present in 23 (69.7%) patients. The comparison of the corneal densitometry values revealed that the densitometry measurements in anterior concentric zones were slightly higher in affected eyes. Corneal aberrometric values were also slightly higher in affected eyes. No significant difference was observed between affected and sound eyes in terms of corneal keratometric, densitometric, and aberrometric values (p&gt;0.05, for all).&#x0D; Conclusions: Corneal exposure leading to visual complications, and lowering of the tear production may lead to dry eye in BP patients. The examination of the ocular surface to observe the ocular findings of BP is essential. The main priority of the ophthalmologist is to ensure adequate corneal protection to prevent undesired ocular outcomes.

Assessment of corneal topographic patterns and densitometric parameters in patients with severe delayed-onset mustard gas keratopathy and patients suffered from corneal scarring

Purpose: This study was performed to evaluate the densitometric values and the type of corneal topographic pattern extracted from Pentacam HR (OCULUS, Wetzlar, Germany) in two groups of severe delayed-onset mustard gas keratopathy (DMGK) and old herpes simplex corneal scarring. Materials and methods: Twenty eyes of each group were enrolled to the study and were examined using the Pentacam HR. Total corneal densitometry was measured over a 12 mm diameter area, divided by annular concentric regions and depths. Also, the corneal topographic pattern from the axial curvature map of the anterior corneal surface was determined in all patients. Results: The most common observed patterns in severe DMGK and old corneal scarring were superior steepening and irregular pattern, respectively. Densitometry measurement in 10 to 12 mm in diameter in DMGK was significantly higher than old corneal scarring. There were not any significant differences in other densitometry values between the groups. Conclusion: It seems that clinical evaluation of corneal structure using Pentacam can improve our knowledge about this rare mustard gas keratopathy. Keywords: Delayed-onset mustard gas keratopathy; Corneal scarring; Pentacam HR; Densitometry; Corneal pattern.

Study of Gas Holdup Distribution in Cylindrical Split Airlift Reactor by Using Gamma-Ray Densitometry (GRD)

The local gas holdup details and behaviors in the cylindrical split airlift column by using an unconventional gamma-ray densitometry (GRD) measurement in non-invasive manner technique was investigated for the first time in this work for such kind of airlift column. With different gas velocities, 1, 2, and 3 cm/s, at three various axial planes (different levels) in z = 3, 60, and 110 cm were studied for local distribution in radial gas holdup profiles. The distribution in gas–liquid phases (air-water system) in the entire split reactor column, in the rising and descending sides, including their behavior in the upper and lower zones of the split plate, were investigated as well. The results of this study showed that approximately all reactor zones had exemplary gas–liquid phases and that there was a large magnitude over both the dividing ring and the top sections. The results further indicated that the distribution of which flow variable in the implementation of the cylindrical split reactor can have an important impact on its behavior, especially for cultivating applications of microorganisms. These data can be used as benchmarks results for CFD simulations and validation.

Repeatability of Corneal Densitometry Measurements using a Scheimpflug Camera in Healthy Normal Corneas.

Purpose:To determine the repeatability of corneal densitometry measured by the Scheimpflug imaging system.Methods:This cross-sectional study was conducted on photorefractive keratectomy candidates. One eye of each participant underwent imaging using Pentacam HR three times, 10 min apart. The repeatability of densitometry measurements was evaluated in four concentric annuli around the corneal apex and in different corneal depths. The repeatability of the measurements was evaluated using the intraclass correlation coefficient (ICC), repeatability coefficient (RC), and coefficient of variation (CV). The difference of repeatability between layers and zones was tested by tolerance index (TI).Results:Sixty eyes of sixty patients with a mean age of 27.76 ± 3.93 years were studied. Half of the participants were female (n = 30, 50%). ICC was above 0.9 in all corneal parts. The posterior layer and central zones showed the least variability of densitometry measurements considering the CV values. The RC was 2.06, 1.17, and 0.92 in anterior, central, and posterior layers, respectively. The RC was 0.88, 0.71, 1.51, and 4.56 in 0–2, 2–6, 6–10, and 10–12 mm circles, respectively. Only the reliability of densitometry in 10–12 mm annulus was statistically lower than the central zone (TI = 0.71).Conclusions:Corneal densitometry measurements provided by the Pentacam had good repeatability. The repeatability of densitometry measurements decreased from the center to the periphery (with an exception for 0–2 mm and 2–6 mm) and from the posterior to the anterior of the cornea. The reliability of the 10–12 mm zone was markedly less than other zones.

Designing Clinical Trials in "Regular" COPD Versus Alpha-1 Antitrypsin Deficiency-Associated COPD: "More Alike Than Unalike?"

Alpha-1 antitrypsin deficiency (AATD) predisposes to emphysema, liver disease, and panniculitis. This emphysema risk naturally invites a comparison between "regular" chronic obstructive pulmonary disease (COPD) (i.e., unrelated to AATD) and AATD-associated emphysema. Several features characterize both conditions. Both can be life-limiting and highly debilitating. Both are highly under-recognized. An important corollary of this comparison between "regular" COPD and AATD-associated COPD is whether both should be treated similarly and whether clinical trials to assess new therapies can be conducted similarly in both. Here, the distinctions between "regular" COPD and AATD-associated COPD are quite pronounced. Therapeutically, sparse available data suggest that lung volume reduction surgery confers less improvement in forced expiratory volume in 1 second (FEV1) in AATD and that such benefits are shorter-lived. Perhaps the most striking contrast between the 2 conditions is that clinical trial designs and conduct are necessarily very different. The relative scarcity of diagnosed individuals with AATD hampers recruitment to trials. Furthermore, primary outcome measures in trials of "regular" COPD must differ markedly from those of AATD-associated emphysema. Specifically, power calculations show that FEV1 and exacerbation frequency, which are amply represented as endpoints in large COPD trials, are infeasible in studies of AATD-associated emphysema. Rather, in the 3 available randomized controlled trials of intravenous augmentation therapy, the rate of emphysema progression based on serial computed tomography densitometry measurements has been the only feasible primary outcome measure. These considerations underscore the distinctive challenges and needs of conducting treatment trials in AATD-associated emphysema and emphasize that, with regard to clinical study design, the 2 conditions are "more unalike than alike."

Sarcopenia in neurodegenerative disorders

Sarcopenia is a progressive generalized muscle disorder, associated with an increased risk of falls, fractures, physical disability, and mortality. Sarcopenia criteria are based on an assessment of a triad of symptoms – a decrease in muscle mass, muscle strength, and impaired physical performance. The most common diagnostic methods are handgrip dynamometry, densitometry, bioimpedansometry, and gait speed measurement. These methods have high accuracy and prognostic value, but are not always applicable to neurological patients. The article discusses sarcopenia detection in neurological practice, as well as its connection with neurodegenerative disorders – Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis. Having a number of common pathophysiological mechanisms, each of the diseases is characterized by a specific phenotype of muscle atrophy. The high incidence of sarcopenia symptoms in neurodegenerative diseases and the common mechanisms of their development allow us to treat sarcopenia as an overlap syndrome of neurodegenerative disorders.

The Relationship between Serum Sclerostin Levels and Bone Mineral Disorders and Vascular Calcification in Hemodialysis Patients

Background and aim of the study: Sclerostin is produced by osteocytes and has been shown to down-regulate the synthesis of many markers of bone formation by osteogenic cells. The aim of this study to investigate the relationship between serum sclerostin levels and bone mineral disorders and vascular calcification in hemodialysis patients (HD).&#x0D; Methods:This is a cross-sectional study of 70 patients with ESRD on regular HD for at least six months, Theodor Bilharz Research Institute, Giza, Egypt.Twenty-five subjects who matched the ages, genders, and demographics of the study patients were included as a control group.All patients and control groups included in the study underwent a full through history and clinical examination. Serum calcium, phosphorus, alkaline phosphatase and intact PTH (iPTH) levels were measured. Serum sclerostin was measured by an ELISA. Bone Mineral Densitometry Measurements BMD (g/cm2) was determined by dual-energy X-ray absorptiometry (DXA). CT scan was done to detect the presence or absence of vascular calcification and transthoracic echocardiogram to detect the presence or absence of valvular calcification.&#x0D; Results:The mean seumscleostin levels was a statistically significant high in the HD patients when compared with the control group (156.8 ±121.4 Vs.29.38±0.84, p =0.0001 ) and statistically significant high mean ALP in the HD patients when compared with the control group (147.2 ± 94.3 Vs. 38.8 ±23.4, p = 0.0001). The mean BMD was statistically significant low in the HD patients when compared with the controls (0.839±0.086 g/ m2 Vs.1.306 ±0.153 g/ m2, p = 0.0001).The mean seumscleostin levels was statistically significant high in the HD patients with vascular and valvular calcification when compared with HD patients without calcification.Using spearman correlation coefficient analysis, there was statistically significant negative correlations between serum sclerostin levels and iPTH(r=-0.362, p =0.0021), ALP (r=-0.301, p =0.0114), and BMD (r=-0.469, p =0.0278 ), and there was a statistically significant positive correlation between serum sclerostin levels and phosphate(r=0.5829, p =0.0001 ).Independent predictors of BMD in HD patients were determined using multi-variate regression analysis. Sclerostin levels, iPTH, ALP, and age were found to be independent predictors of BMD.&#x0D; Conclusion: High sclerostin levels in patients with ESRD on HD were associated with high risk of vascular and valvularcalcification and were independent predictors of low BMD in such population.

Objective Assessment of Corneal and Lens Clarity in Patients with COVID-19.

The severe acute respiratory syndrome coronavirus 2 virus, which causes the coronavirus disease 2019 (COVID-19) pandemic, can bind to epithelial cells in the human cornea and conjunctiva, which may result in changes of corneal and lenticular densitometry. We aimed to report the corneal and lenticular clarity of patients who had been diagnosed previously with confirmed infection of COVID-19. This was a prospective, cross-sectional study. Fifty-three patients who had recovered from COVID-19 and 51 healthy individuals who had not had COVID-19 (control) were included in this study. Measurement of the corneal (at a corneal diameter of 12 mm) and lens densitometry of participants was performed using a Pentacam HR Scheimpflug imaging system. Three different optimal depths as anterior, central, and posterior layers and four concentric zones, consisting of diameters of 0 to 2, 2 to 6, 6 to 10, and 10 to 12 mm, were chosen to perform the corneal densitometric measurements. The mean lenticular densitometric values were calculated in zone 1 at 2.0 mm, zone 2 at 4.0 mm, and zone 3 at 6.0 mm by taking the central part of the pupil as reference point. When compared with the individuals in the control group, the corneal densitometry measurements in the patients in the COVID-19 group were considerably higher in anterior 0 to 2 mm, 2 to 6 mm, 6 to 10 mm zones and total diameter; center 0 to 2 and 2 to 6 mm zones and total diameter; posterior 0 to 2 mm zone; and total corneal 0 to 2 and 2 to 6 mm zones and total diameter (P < .05, for each). When compared with the individuals in the control group, all of the lens densitometry measurements, except for those located in zone 1, were determined to be significantly higher among the patients in the COVID-19 group (P < .05, for each). Significant alterations were found in corneal and lenticular densitometric values in patients who had had COVID-19. The virus could adversely affect cornea and lens transparency.

The effect of topical bimatoprost on corneal clarity in primary open-angle glaucoma: a longitudinal prospective assessment.

To study the effect of topical bimatoprost on the corneal optical density values using a dual Scheimpflug Placido analysis system. This longitudinal case-control study included 18 patients with newly diagnosed primary open-angle glaucoma who received topical bimatoprost as a first-line treatment and 20 healthy individuals (age and sex-matched controls). Corneal densitometry data were obtained using the dual Scheimpflug analyzer at pre-treatment and 1st, 6th, 12th, 18th months of post-treatment. Repeated measures of ANOVA and Pearson correlation tests were used for statistical analysis. There were statistically significant differences between pre-treatment and post-treatment 1st and 6th months corneal densitometry values (p < 0.001, p = 0.007, respectively). However, there was no statistically significant difference between the post-treatment 12th and 18th months (p > 0.05). Corneal densitometry values decreased during the 1st month. Intraocular pressure (IOP) differences were statistically significant between baseline and 1month after treatment (P < 0.001), however not statistically significant between the 1st and 6th, 6th and 12th, 12th and 18th months after treatment (p > 0.05, for all). Corneal densitometry was not correlated with IOP (r = - 0.037, p = 0.44). In the control group, there was no statistically significant difference between baseline and post-baseline 18th-month corneal densitometry measurements (p > 0.05). Topical bimatoprost administration might result in a decrease in corneal densitometry measurement. It is of clinical importance that topical bimatoprost administration can affect corneal transparency and cause a possible alteration in corneal properties.

Early decrease in lean mass and bone mass in postmenopausal women: a cross-sectional study

Objective The effect of menopause transition in body composition was evaluated in a cross-sectional study. Method The study was carried out in an outpatient clinic of Brazil enrolling premenopausal (n = 64) and postmenopausal (n = 42) women aged between 44 and 52 years, with weight stability (±2 kg) for at least 6 months before evaluation. Participants answered a sociodemographic semi-structured questionnaire, the Menopause Rating Scale, the International Physical Activity Questionnaire, 24-h dietary recall and a visual analogue scale of appetite. Blood biochemical, anthropometry and densitometry measurements were used for body composition estimation. Results Most participants were overweight (31.4%) or obese (45.7%) and categorized as ‘high active’ in physical activity (65.7%). Lean mass and bone mass decreased in the first few years of menopause. A metabolic turn to an increase of lipids was observed, represented by greater total cholesterol and high-density lipoprotein cholesterol levels. Menopause transition did not alter body fat distribution. Total body fat, android fat and gynoid fat were positively related to smoking habit, and android fat was also positively related to waist circumference. Conclusion Taken together, early postmenopause can be considered a time window of opportunity for preventing ailments such as atherogenic profile, obesity, increased cardiovascular risk and osteoporosis.

Mean-field theory of the interaction of the magnesium ion with biopolymers: the case of lysozyme

A statistical theory is presented of the magnesium ion interacting with lysozyme under conditions where the latter is positively charged. Temporarily assuming magnesium is not noncovalently bound to the protein, I solve the nonlinear Poisson–Boltzmann equation accurately and uniformly in a perturbative fashion. The resulting expression for the effective charge, which is larger than nominal owing to overshooting, is subtle and cannot be asymptotically expanded at high ionic strengths that are practical. An adhesive potential taken from earlier work together with the assumption of possibly bound magnesium is then fitted to be in accord with measurements of the second virial coefficient by Tessier et al. The resulting numbers of bound magnesium ions as a function of MgBr_2 concentration are entirely reasonable compared with densitometry measurements.

Analysis of corneal densitometry and endothelial morphometry in patients with psoriasis

BackgroundTo evaluate corneal endothelial properties and corneal densitometry values in patients with psoriasis and to compare the results with those of healthy controls. MethodsThis prospective, comparative, and cross-sectional study included 106 eyes of 53 patients who were diagnosed with psoriasis and 106 eyes of 53 age-gender matched healthy controls. All patients were evaluated in terms of ocular surface tests such as Schirmer-1 and tear break-up time (TBUT). Corneal endothelial measurements were performed using noncontact specular microscopy. Corneal tomographic and densitometric measurements were obtained using the Scheimpflug imaging system. Measurements were also evaluated according to the psoriasis area and severity index (PASI) score. ResultsThe mean TBUT and Schirmer 1 test values were significantly lower in the psoriasis group than in the healthy controls (p = 0.02, p < 0.001, respectively). While the mean endothelial cell density was significantly lower in patients with psoriasis than the healthy controls (2389.9±314.9 cells/mm2 vs. 2512.4±289.7 cells/mm2, p = 0.02), the mean average endothelial cell area, standard deviation of cell area, coefficient of variation of cell area were significantly higher in patients with psoriasis (426.6±62.7 µm2 vs. 403.2±46.1 µm2, p = 0.01; 206.4±52.3 µm2 vs. 183.2±43.8 µm2, p = 0.006; and 48.1±6.3% vs. 45.7±6.7%, p = 0.04, respectively). Most of the densitometry measurements in concentric zones were higher in patients with psoriasis than in healthy controls, but none of the differences reached statistical significance. ConclusionsA regular eye examination is crucial in patients with psoriasis because corneal structural and functional changes, particularly endothelial alterations, are of utmost importance in planning intraocular surgeries in patients with psoriasis.

Irisin osteoporoz tedavisi takibinde kullanılabilir mi?

Aim: This study aims to investigate the possible roles of irisin as a biomarker in the diagnosis and follow-up of osteoporosis.Methods: A total of 32 postmenopausal osteoporotic and 23 healthy postmenopausal women were received in this study. Bone mineral densitometry (BMD) measurements were done for all patients and control groups. Clinical follow-ups were performed every 3 months. To elicit post-treatment values, at the end of the 12-month follow-up period, all patients underwent BMD and biochemical parameters. Serum irisin concentrations were measured by competitive Enzyme-Linked Immunosorbent Assay (ELISA). The detection range of the used kit was 0.5-30 ng/ml.Results: T-scores were determined as -3.28±0.6 in the BT group (Before treatment) and -2.49±0.7 in the AT group (After-Treatment), and -0.7±0.4 in the control group (C). Significant differences were observed in T scores between BT and AT (p&amp;lt;0.001), BT and C (p&amp;lt;0.001), and AT and C (p&amp;lt;0.001) statistically. Significant differences were observed between BT and C (p&amp;lt;0.001) and AT and C (p=0.002) statistically. There was no significant difference between BT and AT values (p=0.327) statistically. At the correlation analysis, irisin was positively correlated with T score (p=0.01, r=0.25) and 25-OH-D (p=0.02, r=0.23), and negatively correlated with development of osteoporosis (p=0.02, r=-0.23). According to the ROC analysis, irisin levels of 4.1 ng/ml or less can predict pre-treatment osteoporosis with 65.6% specificity and 60% sensitivity (AUC: 65.8%, p=0.014).Conclusion: We concluded that irisin was a protective factor against osteoporosis. It may be used as a biomarker in the diagnosis of osteoporosis.