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  • Author: Hussein Kadhem Al-Hakeim x
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Abstract

Urease catalyzes the hydrolysis of urea to form ammonia and carbon dioxide. The increase in pH from the urease reaction causes a broad range of deleterious effects. Nanoceria (cerium oxide) possesses unique chemical properties under a redox reaction. This study investigated the synthesis of nanoceria via a hydrothermal method and determined its interaction with urease enzyme.

Transmission electron microscopy results showed a cubic-figured nanoceria with a size of ~15 nm. Urease was immobilized on nanoceria through adsorption. The maximum velocity (V max) and Michaelis constant (K m) of the free urease and urease immobilized on nanoceria decreased after interaction with nanoceria, and the Lineweaver-Burk plot showed an uncompetitive inhibition. The thermodynamic study of the adsorption process showed an endothermic reaction. The interaction changed the secondary and tertiary structures of urease as demonstrated by the circular dichroism study (the decrease in both α- and β-structure percentages). The fluorescence study revealed a change in the tertiary structure. The FTIR for the nanoceria—urease complex showed no changes in the covalent bonds, which indicated the involvement of physical forces in the interaction between urease and nanoceria.

Summary

Fetuin-A is a negative acute phase reactant, while procalcitonin is an indicator of severe bacterial infection. Diagnosis of bacterial infection in febrile seizure (FS) is important for choosing the most suitable treatment. In this study, serum fetuin-A was estimated, for the first time, in the inpatients with FS and compared with procalcitonin and blood culture tests.

A total of 60 children (28 male and 32 female) with FS in addition to 30 sex- and age-matched children participated in the study. Patients were classified according to sex, age, PCT level (high PCT>0.5ng/mL), C-reactive protein (CRP, positive >6mg/L), and according to the results of the blood culture.

Fetuin-A level decreased and PCT level increased in FS patients in comparison to those in the control group. These changes are significantly increased (p<0.05) in the positive CRP group compared with that of the negative CRP group. Kernel density estimation showed that procalcitonin is a better indicator of the infection in FS children than fetuin-A . Procalcitonin is more sensitive and specific than fetuin-A and when used together they produce 100% sensitivity and specificity for the diagnosis of bacterial infection in FS patients.

Fetuin-A is low in FS patients and can be used with procalcitonin in the diagnosis of bacterial infection in FS.

Summary

The present study aimed to examine the factors affecting the possible changes in serum fetuin-A in patients with preeclampsia (PE). The examined factors included the parameters of insulin resistance (IR) [(insulin sensitivity (HOMA%S), insulin resistance (HOMA2IR), and beta-cell functions (HOMA%B)], which were calculated using the HOMA2 calculator, and total and ionized calcium and magnesium levels.

Sixty PE patients and thirty healthy pregnant women, which comprised the study group and control group, respectively participated in the present study. Fetuin-A, estradiol, insulin, glucose, total and ionized calcium and magnesium, total protein, albumin, and globulins were measured in their sera.

The results of the present study showed that serum total and ionized magnesium and the I.Ca/Mg ratio decreased in PE women. Although the fasting insulin level and HOMA2IR were higher and HOMA2%S was lower in PE compared with the control women, PE did not appear as an overt insulin-resistant state. Serum fetuin-A was low in PE patients compared with the control group because PE women had proteinuria. Fetuin-A levels were not correlated with the characteristics and IR parameters, cations, and estradiol levels, but it was correlated with the severity of proteinuria.

These results confirmed the hypothesis that proteinuria results in the loss of fetuin-A because it has a low molecular weight.

Summary

Background: The present study aimed to determine the most efficient insulin resistance function related to gly - cemic control expressed as glycated hemoglobin (HbA1c) in type 2 diabetes mellitus patients (T2DM). The other aim is to derive equations for the prediction of beta cell functions containing HbA1c as a parameter in addition to fasting glucose and insulin.

Methods: T2DM Patients were grouped according to the following: (1) degree of control (good, fair, and poor control) and (2) insulin resistance as observed in obtained data and significant differences revealed by the homeostasis model assessment (HOMA) of related parameters (insulin resistance = HOMA2IR, beta-cell function = HOMA%B, and in sulin sensitivity = HOMA%S) among groups. Corre - lations and forecasting regression analysis were calculated.

Results: HbA1c was found to be correlated with insulin resistance parameters in T2DM subgroups. This correlation was also significantly correlated with HOMA%B and the quantitative insulin sensitivity check index (QUICKI) in fair and poor control groups. Regression analysis was used to predict the forecasting equations for HOMA%B. The best applicable equations were derived for healthy control (HOMA2%B=-1.76*FBG+5.00*Insulin+4.69*HbA1c+189.84) and poor control groups (HOMA2%B=0.001* FBG+0.5*Insulin-8.67*HbA1c+101.96). These equations could be used to predict b-cell function (HOMA%B) after FBG, insulin and HbA1c values were obtained for healthy and poor control groups. In the good and fair control groups, the applicability of the HOMA model fails to yield appropriate results.

Conclusions: Beta-cell function is correlated with QUICKI and HbA1c and could be predicted properly from HbA1c, insulin, and glucose in the healthy and poor control groups. New regression equations were established that involve HbA1c.

Abstract

Immobilization of enzymes is a good field of study to extend the life of enzyme and reduce the cost of the chemical processes, such as separation processes. Urease is an important enzyme with medical and industrial applications. The aim of the present study is to prepare an immobilized urease on a strong cation exchange resin (Amberlite IR120 Na) and study its activity and stability. We monitored the release of Na ions in the collected fractions and searching for enzyme in the fractions as indicators of immobilization by ion exchange phenomenon. Sodium is determined by using atomic absorption spectroscopy technique, while the enzyme concentration was tested by Bradford’s method. Immobilized urease activity was evaluated by salicylate-hypochlorite method. The results indicated a complete immobilization of urease enzyme on the resin surface with reserving 92% of the activity of free enzyme. The immobilized urease enzyme on resin showed good stability and it has a 62% of its activity after 154 days of storage at room temperature. It is concluded that a new immobilized urease enzyme system is prepared with good enzyme activity and stability.