Mechanical and thermal stress analysis of hybrid ceramic and lithium disilicate based ceramic CAD-CAM inlays using 3-D finite element analysis / Análise do estresse mecânico e térmico de inlays de cerâmica hibrida e de cerâmica a base de dissilicato de lítio através da análise em 3D de elementos finitos

Objective: The aim of this study was to analyze mechanical and thermal stresses of hybrid ceramic and lithium disilicate based ceramic of CAD/CAM inlays using 3D Finite element analysis. Material and Methods:A three dimensions finite element model of permanent maxillary premolar designed according to standard anatomy with class II cavity preparation for inlay restored with two different ceramic materials: 1- Hybrid ceramic (Vita Enamic), 2- Lithium disilicate based ceramic (IPS e.max CAD). Totally six runs were performed on the model as: One loading case for each restorative material was tested in stress analysis; seven points of loading with 140N vertically applied at palatal cusp tip and cusp slop, marginal ridges and central fossa while the models base was fixed as a boundary condition in the two cases. Two thermal analysis cases were performed for each restoration material by applying 5ºC and 55ºC on the crown surface including the restoration surface. Results:The results of all structures were separated from the rest of the model to analyze the magnitude of stress in each component. For each group, maximum stresses on restorative materials, cement, enamel, and dentin were evaluated separately. Both ceramic materials generated similar stress distribution patterns for all groups when a total occlusal load of 140 N was applied. Conclusion: Thermal fluctuations of temperature have a great influence on the stresses induced on both restoration and tooth structure. IPS e.max CAD produced more favorable stresses on the tooth structure than Vita Enamic. (AU)

Objetivo: O objetivo deste estudo foi analisar o estresse mecânico e térmico de inlays de cerâmica hibrida e a base de dissilicato de lítio através da análise em 3D de elementos finitos. Material e Métodos: Foi realizado o design de um modelo de três dimensões em elementos finitos de um pré-molar superior de acordo com os padrões anatômicos de um preparo de cavidade classe II para restauração de inlay em dois tipos de cerâmicas diferentes: 1 Cerâmica hibrida (Vita Enamic), 2 ­ Cerâmica a base de dissilicato de lítio (IPS e.max CAD). No total, seis execuções foram realizadas no modelo como: Uma carga para cada material restaurador foi testado para análise de tensão; sete pontos de carga com 140N foi aplicado verticalmente na ponta da cúspide palatina, saliência da cúspide, cristas marginais e fossa central enquanto a base do modelo foi fixada como uma condição de limite nos dois casos. Duas análises térmicas foram realizadas para cada material de restauração, aplicando 5ºC e 55ºC na superfície da coroa, incluindo a superfície da restauração. Resultados: Os resultados de todas as estruturas foram separados do resto do modelo para analisar a magnitude do estresse de cada componente. Para cada grupo, o máximo de estresse nos materiais restauradores, cemento, esmalte e dentina foram avaliados separadamente. Padrões similares de distribuição de estresse foram gerados em todos os grupos para ambos os materiais cerâmicos, quando a carga oclusal de 140 N foi aplicada. Conclusão: As variações térmicas de temperatura têm uma grande influência nas tensões induzidas na restauração e na estrutura dentária. IPS e.max CAD produziu tensões mais favoráveis na estrutura dentária do que o Vita Enamic (AU)

Impact of hyperuricemia on cardiovascular system in ESRD patients

Hyperuricemia was found to be associated with hypertension, coronary heart disease, metabolic syndrome and chronic kidney disease. However there are no specific data about the relationship of uric acid to cardiovascular disease and mortality in ESRD patients on chronic hemodialysis. So, we aimed to study the impact of hyperuricemia on cardiovascular system in chronic kidney disease and in ESRD patients on regular hemodialysis. This study included 100 patients in Ashmoun hospital, nephrology department. Patients were chosen and divided into two groups: Group A, 50cases with chronic kidney disease and Group B, 50cases of ESRD on regular hemodialysis. All cases were subjected to full clinical examination, measurement of eGFR, laboratory tests for blood urea, serum creatinine and serum uric acid and ECG. Serum uric acid was significantly higher in dialysis group than CKD group [p<0.01]. There was a highly significant correlation between uric acid and both systolic and diastolic blood pressure in Group A [all p values <0.01]. Also, there was a significant correlation between serum uric acid and eGFR [p<0.05].No significant difference found between Group A and group B as regards ECG findings [p>0.05]. In cases of CKD uric acid is involved in the pathogenesis of renal failure and hypertension. In patients with ESRD, hyperuricemia is not a risk factor for the development of cardiac disease; but it shows reversed epidemiology and becomes a marker of good nutritious status. Further studies should be done on wider scales to evaluate the impact of hyperuricemia on cardiovascular system in hemodialysis patients

[Hemodialysis product: a reliable new index for dialysis adequacy]

Background: To evaluate HD product as new index for adequacy of HD including nutritional status and performance of patients and to compare it to [kt/v] and urea reduction ratio [URR] as a parameters of dialysis adequacy

Aim of the Work: To evaluate HD product as new index for adequacy of HD including nutritional status and performance of patients and to compare it to [kt/v] and urea reduction ratio [URR] as a parametres of dialysis adequacy

Patients and Methods: The study was performed on 75 uremic patients on regular HD for at least one year. The patients were 45 males and 30 females. No attempts were made to match the patients by age or etiology

Results: This study showed that HDP is considered a valid test with high sensitivity and specifity and easy test for adjusting HD dose to achieve an adequate HD, however further studies needed to assess HDP as are new index for adequacy of HD

Conclusion: HDP may be used as a valid test with high sensitivity and specifity and easy test for adjusting HD dose to achieve an adequate HD, however further studies needed to assess HDP as are new index for adequacy of HD

case of Gitelman's syndrome presenting with hypocalcemia

Gitelman's syndrome [GS] is an autosomal recessive disorder caused by a defect of the thiazide-sensitive NaCl cotransporter [TSC] at the distal tubule, characterized by hypomagnesemia, hypokalemic alkalosis and hypocalciuria. This condition was previously confused with Bartter's syndrome [BS]. The documentation of hypocalciuria helps to differentiate this syndrome from BS. We report a 35-year-old female patient presented to our hospital with a history of muscle weakness and carpal spasm. She showed hypokalemia, hypocalcemia, hypomagnesemia and hypocalciuria. She was treated with electrolyte supplements

Study of the association between the human leukocyte antigen class I molecules and remitting relapsing multiple sclerosis MS

The aim of this work is to study the frequencies of different HL4 class I subtypes in Egyptian patients with remitting relapsing MS in order to find out genetic determinants to disease susceptibility among this genetic group. The study was carried out on twenty patients having Ms according to McDonald's criteria, excluding those with clinical courses other than the remitting-relapsing one. All patients subjected to complete history taking, full physical and neurological examination, routine lab investigations, MRI of the brain and/or spinal cord, also HLA class I typing using the complement dependent microlymphocytotoxicity test. The result of HLA typing were compared to twenty healthy controls matched for age. The study revealed the following results. o The most frequent HLA class I subtypes in our study group were: HLA-A1 [40%], A2 [30%], B7 [25%], A28 [15%], and Cw6 [15%]. o Among those subtypes only HLA-B7 showed a statistically significant association with the MS patients suggesting a role of this HLA class I subtype in modulating susceptibility to the disease. o The HIA-Cw4 subtype showed a tendency toward an association with the control group approaching but not reaching a statistical significance suggesting a role of this subtype as a protective factor against MS. However further confirmation is required to support this finding. o The HLA-B7 subtype was significantly associated with the presence of emotional disturbance in the MS patients suggesting a role of this subtype in modulating the clinical picture of the disease. o The HLA-A2 subtype was significantly associated with the absence of sphincteric disturbance in the MS patients suggesting a protective role of this subtype against this particular clinical defect. This subtype may also have a similar protective role against developing emotional disturbance although this finding was only near significant. The above mentioned results agreed with a few reports from some parts of the world and disagreed with many others suggesting a considerable difference in genetic determinants of MS between different populations

Cytogenetic study in juvenile myoclonic epileptic patients

The association of chromosomal imbalance and neurological abnormalities is well known. These chromosomal abnormalities may indicate that chromosomal sites where atypical neurological characteristics could be mapped. The purpose of our study was to search for cytogenetic abnormalities in patients with juvenile myoclonic epilepsy. This work was carried out on fifteen patients presenting to Epilepsy Centerof Neurology Department of Alexandria Main University Hospital. The age of juvenile myoclonic patients ranged from 16 to 38 years. Ten patients have myoclonic and generalized Tonic-Clonic seizures, 3 patients have myoclonic, absences, and generalized tonic-clonic seizures, and 2 patients have myoclonic seizures only. All patients were cytogenetically normal as all of them had normal karyotypes

radiographic assessment of craniofacial growth pattern changes in children with chronic renal failure [by digital cephalometric study]

The purpose of the present study to evaluate the craniofacial growth changes in patients with chronic renal failure using a digital cephalometric analysis system. This study was carried out on 24 children [ 12 male and 12 female] with chronic renal failure aged between 6-9 years. The results were compared with control group of 24 normal subjects [12 male and 12 female] having the same age. For each subject in the study a lateral cephalogram was taken. Each cephalogram was scanned, traced and analyzed using a digital cephalometric system program. The data of the digital analysis were collected, tabulated and statistically analyzed. In conclusions: the children who suffered from chronic renal failure had several changes in craniofacial growth pattern in comparison with normal children with the same age group. Also, digital cephalometric radiographic assessment is an accepted method for evaluation the craniofacial growth pattern

Effect of haemodialysis on intra dialytic calcium, phosphorus, magnesium, levels in relation to autonomic nervous system activity

Autonomic nervous system dysfunction is common in uremia and in patients under hemodialysis. Changes in serum calcium, serum phosphorus and serum magnesuim always occur during hemodialysis. The relation between these changes and autonomic nervous system activity during hemodialysis has not been fully studied. This study was carried out on 30 patients with chronic renal failure on regular hemo- dialysis with nearly similar age group. We measured serum calcium, serum phosphorus and serum magnesium throughout the session [at predialysis state, middialysis state: after 2 hours of the session and postdialysis: at the end of the hemodialysis Session]. We have also assessed autonomic function [sympathetic by cold pressor test and parasympathetic by Valsalva maneuver test]. Autonomic function tests were assessed at predialysis state, middialysis state and postdialysis state. Calcuim level uncreased throughout the session [P<0.05], phosphorus leuel and Magnesium levels decreased, [P<0.001] and [P<0.05], throghout session . As reguards parasympathetie dysfunetion, there was a significamt relation [P<0.05] with calcuim changes at predialytic and post dialytic states, a highly significant relation [P<0.001] with phosphorus and [P<0.05] with magnesiun, both at predialysis states. Concerging sympathetie dysfunction, there was a significant relation [P<0.05] with calcium levels at end of session. There was a signifcant relation [P<0.05] with predialytic and postdialytic phosphorus levels .There was also significant relation [P<0.05] with predialytic magnesium level