Omar Y. Abdelaziz

Biological valorization of low molecular weight lignin.

Lignin is a major component of lignocellulosic biomass and as such, it is processed in enormous amounts in the pulp and paper industry worldwide. In such industry it mainly serves the purpose of a fuel to provide process steam and electricity, and to a minor extent to provide low grade heat for external purposes. Also from other biorefinery concepts, including 2nd generation ethanol, increasing amounts of lignin will be generated. Other uses for lignin - apart from fuel production - are of increasing interest not least in these new biorefinery concepts. These new uses can broadly be divided into application of the polymer as such, native or modified, or the use of lignin as a feedstock for the production of chemicals. The present review focuses on the latter and in particular the advances in the biological routes for chemicals production from lignin. Such a biological route will likely involve an initial depolymerization, which is followed by biological conversion of the obtained smaller lignin fragments. The conversion can be either a short catalytic conversion into desired chemicals, or a longer metabolic conversion. In this review, we give a brief summary of sources of lignin, methods of depolymerization, biological pathways for conversion of the lignin monomers and the analytical tools necessary for characterizing and evaluating key lignin attributes.

Endovascular management of early hepatic artery thrombosis after living donor liver transplantation

To study the feasibility of endovascular management of early hepatic artery thrombosis (HAT) after living‐donor liver transplantation (LDLT) and to clarify its role as a less invasive alternative to open surgery. A retrospective review of 360 recipients who underwent LDLT. Early HAT developed in 13 cases (3.6%). Diagnosis was performed using Doppler, CT angiography, and digital subtraction angiography. Intra‐arterial thrombolysis (IAT) was performed using streptokinase or tPA. In case of underlying stricture, PTA was attempted. If the artery did not recanalize, continuous infusion was performed and monitored using Doppler US. Initial surgical revascularization was successful in 2/13 cases. IAT was performed in 11/13 cases. The initial success rate was 81.8% (9/11), the failure rate was 18.2% (2/11). Rebound thrombosis developed in 33.3% (3/9). Hemorrhage developed after IAT in 2/11 cases (18.2%). Definite endovascular treatment of HAT was achieved in 6/11 cases (54.5%) and definite treatment (surgical, endovascular or combined) in 9/13 cases (69%). (Follow‐up 4 months–4 years). Endovascular management of early HAT after LDLT is a feasible and reliable alternative to open surgery. It plays a role as a less invasive approach with definite endovascular treatment rate of 54.5%.

Portal vein thrombosis and arterioportal shunts: Effects on tumor response after chemoembolization of hepatocellular carcinoma

AIM To evaluate the effect of portal vein thrombosis and arterioportal shunts on local tumor response in advanced cases of unresectable hepatocellular carcinoma treated by transarterial chemoembolization. METHODS A retrospective study included 39 patients (mean age: 66.4 years, range: 45-79 years, SD: 7) with unresectable hepatocellular carcinoma (HCC) who were treated with repetitive transarterial chemoembolization (TACE) in the period between March 2006 and October 2009. The effect of portal vein thrombosis (PVT) (in 19 out of 39 patients), the presence of arterioportal shunt (APS) (in 7 out of 39), the underlying liver pathology, Child-Pugh score, initial tumor volume, number of tumors and tumor margin definition on imaging were correlated with the local tumor response after TACE. The initial and end therapy local tumor responses were evaluated according to the response evaluation criteria in solid tumors (RECIST) and magnetic resonance imaging volumetric measurements. RESULTS The treatment protocols were well tolerated by all patients with no major complications. Local tumor response for all patients according to RECIST criteria were partial response in one patient (2.6%), stable disease in 34 patients (87.1%), and progressive disease in 4 patients (10.2%). The MR volumetric measurements showed that the PVT, APS, underlying liver pathology and tumor margin definition were statistically significant prognostic factors for the local tumor response (P = 0.018, P = 0.008, P = 0.034 and P = 0.001, respectively). The overall 6-, 12- and 18-mo survival rates from the initial TACE were 79.5%, 37.5% and 21%, respectively. CONCLUSION TACE may be exploited safely for palliative tumor control in patients with advanced unresectable HCC; however, tumor response is significantly affected by the presence or absence of PVT and APS.

A hierarchical approach for the design improvements of an Organocat biorefinery

Lignocellulosic biomass has emerged as a potentially attractive renewable energy source. Processing technologies of such biomass, particularly its primary separation, still lack economic justification due to intense energy requirements. Establishing an economically viable and energy efficient biorefinery scheme is a significant challenge. In this work, a systematic approach is proposed for improving basic/existing biorefinery designs. This approach is based on enhancing the efficiency of mass and energy utilization through the use of a hierarchical design approach that involves mass and energy integration. The proposed procedure is applied to a novel biorefinery called Organocat to minimize its energy and mass consumption and total annualized cost. An improved heat exchanger network with minimum energy consumption of 4.5 MJ/kgdry biomass is designed. An optimal recycle network with zero fresh water usage and minimum waste discharge is also constructed, making the process more competitive and economically attractive.

Serum Tumour Necrosis Factor Alpha Levels in Benign and Malignant Lesions of the Endometrium in Postmenopausal Women; A preliminary study

Tumour necrosis factor alpha (TNF alpha) concentration was determined by a solid phase immunoradiometric assay in sera of 20 healthy postmenopausal women (reference group), 10 women suffering from postmenopausal bleeding with histologically confirmed cystic glandular hyperplasia, and 10 postmenopausal bleeding patients with histologically confirmed endometrial adenocarcinoma. In cases of endometrial adenocarcinoma serum TNF alpha (157.6 +/- 28 pg/ml) was found to be significantly higher than in controls (80.6 +/- 4.1 pg/ml). The rate of abnormally high values of serum TNF alpha increased with advancing stage of the disease. On the other hand, serum TNF alpha level in cases of endometrial hyperplasia (38 +/- 6 pg/ml) was significantly lower than in healthy individuals. It seems that the rise of serum TNF alpha in cases of endometrial carcinoma represents a possible mechanism of immune surveillance. The results suggest clinical usefulness of serum TNF alpha estimations for the differential diagnosis of benign and malignant lesions of the endometrium in women with postmenopausal bleeding.

Doppler ultrasonography in living donor liver transplantation recipients: Intra- and post-operative vascular complications

Living-donor liver transplantation has provided a solution to the severe lack of cadaver grafts for the replacement of liver afflicted with end-stage cirrhosis, fulminant disease, or inborn errors of metabolism. Vascular complications remain the most serious complications and a common cause for graft failure after hepatic transplantation. Doppler ultrasound remains the primary radiological imaging modality for the diagnosis of such complications. This article presents a brief review of intra- and post-operative living donor liver transplantation anatomy and a synopsis of the role of ultrasonography and color Doppler in evaluating the graft vascular haemodynamics both during surgery and post-operatively in accurately defining the early vascular complications. Intra-operative ultrasonography of the liver graft provides the surgeon with useful real-time diagnostic and staging information that may result in an alteration in the planned surgical approach and corrections of surgical complications during the procedure of vascular anastomoses. The relevant intra-operative anatomy and the spectrum of normal and abnormal findings are described. Ultrasonography and color Doppler also provides the clinicians and surgeons early post-operative potential developmental complications that may occur during hospital stay. Early detection and thus early problem solving can make the difference between graft survival and failure.

Diagnostic value of combined static-excretory MR Urography in children with hydronephrosis.

The aim of this study was to determine the feasibility, accuracy and diagnostic potential of combined static-excretory MR Urography in children with sonographically detected hydronephrosis. We prospectively evaluated 28 children (11 girls and 17 boys), mean age 8.3 years (range 2 months–16 years). Static-excretory MR Urography was performed in all cases. The results of MR Urography were compared with the results of other imaging modalities, cystoscopy and surgery. In 28 children, 61 renal units were evaluated by MR Urography (the renal unit is the kidney and its draining ureter). The final diagnoses included: normal renal units (n = 23); uretropelvic junction obstruction (n = 14); megaureter (n = 8); midureteric stricture (n = 1), complicated duplicated systems (n = 5), post ESWL non-obstructive dilation (n = 2), extrarenal pelvis (n = 4), dysplastic kidney (n = 4). Complex pathology and more than one disease entity in were found in 7 children. The MRI diagnosis correlated with the final diagnosis in 57 units, with diagnostic accuracy 93.4%. In conclusions static and excretory MRU give both morphological and functional information in a single examination without exposure to ionizing radiation and iodinated contrast agent. It is a valuable imaging technique for children with upper urinary tract dilatation; especially in cases of complex congenital pathologies and severely hydronephrotic kidney.

Serum interleukin-2 and soluble interleukin-2 receptor in gestational trophoblastic diseases.

To investigate serum interleukin-2 (IL-2) and soluble interleukin-2 receptor (SIL-2) levels in gestational trophoblastic diseases (GTD). Sixty-six patients with GTDs and 23 first-trimester healthy pregnant women (controls) participated in this study. According to the World Health Organization scoring system, GTDs were subgrouped into the following groups: 30 hydatidiform mole spontaneous regression (HMSR), 12 postmolar gestational trophoblastic tumors of high risk (PMHR), 14 low-risk choriocarcinomas, and ten high-risk choriocarcinomas. Before treatment, a blood sample from each case was assayed for β-hCG by radioimmunoassay, IL-2 by IRMA, and SIL-2R by enzyme-linked immunosorbent assay. Follow-up β-hCG assays were carried out at weekly intervals after treatment for 3 months, then monthly for 1 year. Serum IL-2 levels in all subgroups of GTD were significantly lower than that of controls. Meanwhile, there were concomitant significant elevations of serum SIL-2R, showing mean rises of 3.86-fold, 3.9fold, twofold, and 6.1-fold for cases of HMSR, PMHR, low-risk choriocarcinoma, and high-risk carcinoma, respectively. All cases of high-risk choriocarcinoma revealed abnormally high SIL-2R values. There was a significant positive correlation between serum β-hCG and SIL-2R concentrations. The possible causes of IL-2 decreases and SIL-2R increases may indicate a defective immune response in GTDs. The high correlation between S1L-2R level and tumor burden suggests the use of serum SIL-2R assay for disease monitoring: SIL-2R is indirect marker of tumor activity, and it is useful in the differential diagnosis of GTD because a normal value of serum SIL-2R excludes high-risk cases of choriocarcinoma.

The cardiovascular safety of triphasic contraceptive steroids

It was hypothesized that estrogen-induced cardioprotection is mediated by up-regulation and down-regulation of expression of nitric oxide (NO) and P-selectin, respectively. Published data on circulating levels of the vasodilator NO, atherogenic glycoprotein P-selectin, and lipoprotein-a [Lp(a)] in users of triphasic contraceptive steroids are lacking. A total of 30 healthy women (nonusers, controls) and 82 women using oral triphasic contraceptive steroids (ethinyl estradiol and levonorgestrel: Triovlar, Schering AG) for 18 to 24 cycles participated in this study. Fasting blood samples were obtained from users and nonusers for the determination of P-selectin and Lp(a) by enzyme immunoassay and NO by a colorimetric method. The serum Lp(a) levels in OC users were significantly higher than those of nonusers. On the other hand, the serum NO levels in OC users were significantly elevated when compared to nonusers. Plasma P-selectin was significantly lowered in OC users p < 0.005. These results demonstrate the beneficial effects of ethinyl estradiol in the triphasic contraceptive regimen. Ethinyl estradiol may afford a degree of anti-atherogenic-cardioprotective effect by up-regulation of the expression of the vasodilator NO and down-regulation of the expression of the atherogenic P-selectin. This may outweigh the cardiovascular risk of the increased atherogenic Lp(a). This study may explain the very low rate of mortality from venous thromboembolism in OC users, which compares favorably with the risks that many people accept in daily life.

Plasma β-endorphin level in cases of luteal phase defect

Objective To evaluate β -endorphin secretion in euprolactinemic cases of luteal phase defect (LPD). Design Serial blood samples from the 18th to the 26th day of the menstrual cycle were assayed for β -endorphin, progesterone (P), estradiol (E 2 ), and prolactin (PRL) in cases of LPD and controls. Diagnosis of LPD was based on determinations of serum P and premenstrual endometrial biopsy. Setting From Cairo University Hospitals. Patient, Participants Twenty-six women with LPD and 8 normal fertile women (controls) were chosen. Interventions None. Main Outcome Measures β -Endorphin, P, E 2 , and PRL concentrations were determined by the corresponding 125 I radioimmunoassay. Results Plasma β -endorphin level in cases of LPD varied from 2.58 to 9.14 pmol/L, whereas the level of controls varied from 2.41 to 5.57 pmol/L. The mean value of plasma β -endorphin in cases of LPD was significantly higher than that of controls by 146% ( P 2 level did not differ significantly from that of controls. Conclusion The possible sources of β -endorphin rise and its implication in the etiology of LPD are explained.