Effect of shading imposed by the algae Chaeotomorpha linum loads on structure, morphology and physiology of the seagrass Cymodocea nodosa.

In shallow coastal waters, seagrass and macroalgae occur together but under eutrophic conditions, bloom-forming algae can take over seagrasses causing an irreversible regime shift. Understanding the effect of macroalgae loads on seagrass meadows at an early stage can help prevent the loss of these ecosystems and the services they provide. In the present study, in situ experiments were conducted for 90 days in Bekalta (eastern coast of Tunisia) to assess the response of the seagrass Cymodocea nodosa when challenged with shading induced by filamentous macroalgae Chaetomorpha linum. Structural, morphological and physiological variables were regularly measured during the experiment. Shaded plants showed a sharp decline in shoot density, growth rate, and above-ground biomass, the impact being more pronounced on the physiological traits. Besides, shading by C. linum induced a significant increase in the contents of leaf photosynthetic pigments and phenolic compounds, whereas causing a decrease in soluble protein and sugar concentrations. Thus, shading imposed by C. linum loads appeared to induce a phoadpatative response in C. nodosa concomitant with carbon mobilization.

Treatment of esophageal perforation: A review of our experience at a tertiary referral hospital spanning the past 19 years.

INTRODUCTION AND AIMS: Esophageal perforation is an uncommon event that is a medical/surgical emergency, with a 15-30% mortality rate. The aim of the present study was to communicate our experience in the management of esophageal perforation, evaluating the different strategies utilized, in an effort to establish measures to guide decision-making in selecting treatment. MATERIALS AND METHODS: A retrospective descriptive study was conducted on patients diagnosed with esophageal perforation at our hospital center, within the time frame of 2000 and 2019. RESULTS: Over the past 19 years, 15 patients were diagnosed with esophageal perforation. Surgical treatment was carried out in 80% of the cases. Primary closure, reinforced with plasty, was performed in 67% of the patients, of whom 62.5% had early diagnosis and a 100% survival rate. Diagnosis was late in 37.5% of the cases, with a 33.3% survival rate. Esophagectomy and gastric pull-up were performed on 25% of the patients, 66.6% of whom had early diagnosis and a 100% survival rate. In the 33.3% that had late diagnosis, the mortality rate was 100%. Esophagectomy, with cervical esophagostomy and feeding jejunostomy, was performed on one of the patients (8.3%) that had early diagnosis and a 100% survival rate. CONCLUSIONS: The main survival predictor in esophageal perforation is the interval of time between the injury and its diagnosis, and in turn, the resulting treatment. Each patient with esophageal perforation should have individualized treatment to adequately manage the condition.

Non-Invasive Assessment of Graft Fibrosis After Living Donor Liver Transplantation: Is There Still a Role for Liver Biopsy?

Non-invasive methods have evolved as a surrogate for liver biopsy such as indirect markers (aspartate transaminase to platelet ratio index, fibro-α score), transient elastography (TE), and magnetic resonance elastography (MRE). The aim of this study is to prospectively compare the value of MRE, TE, and indirect markers in detecting and staging allograft fibrosis compared to liver biopsies in patients who have undergone living donor liver transplantation for complications related to hepatitis C virus. A total of 31 living donor liver transplantation recipients with hepatitis C virus recurrence underwent a liver biopsy, TE, and MRE within 3 months of a liver biopsy. Fibrosis was assessed according to the biopsy and staged according to Metavir criteria. There was a significant correlation between both MRE and fibro-α scores, as well as histologic classification by liver biopsy (P = .02, .002). The diagnostic accuracy of MRE and fibro-α scores in diagnosing significant fibrosis (F ≥ 3) was measured as the area under the curve (.708 and .833, respectively). Both methods showed good diagnostic performance. TE and aspartate transaminase to platelet ratio index were insignificantly correlated with the degree of fibrosis in liver biopsy (P value of .134, .535). At a cutoff value of 5.5 kPa, MRE predicted graft fibrosis (Metavir stage ≥ 3) with 71.43% sensitivity, 75% specificity, 45.5% positive predictive value, and 90% negative predictive value; at a cutoff value > 1.47, fibro-α scores predicted significant graft fibrosis (Metavir stage ≥ 3) with 85.7% sensitivity and 70.83% specificity, with a positive predictive value of 46.2% and a negative predictive value of 94.4%. These data suggest that non-invasive methods could be considered a reliable tool in assessing significant graft fibrosis post-living donor liver transplantation.

Impact of anthropometric measures and serum leptin on severity of gastroesophageal reflux disease.

The aim of this prospective study was to evaluate the impact of obesity, determined by different anthropometric measures, on clinical and endoscopic severity of GERD and the relation between serum leptin and clinical and endoscopic severity of GERD in Egyptian patients. The study was carried out at Ain Shams University Hospitals and Theodor Bilharz Research Institute, Cairo, Egypt. A total of 60 patients with clinically and endoscopically evident gastroesophageal reflux disease (GERD) were enrolled in this study as well as 20 healthy subjects matched for age and gender serving as the control group. Patients were divided according to their body mass index (BMI) into two groups: group 1 (n = 30): overweight and obese (BMI ≥ 25 and/or waist-to-height ratio [WHtR] ≥ 0.5) and group 2 (n = 30): normal weight (BMI ≥ 18 to < 25 and/or WHtR ≥ 0.4 to < 0.5). Upper gastrointestinal endoscopy, anthropometric measures, and symptom severity score questionnaire were done for all patients. Serum leptin hormone was assessed for patients and control groups.The evidence revealed statistically significant difference between the two groups in terms of different anthropometric measures (P < 0.00) except the height (P < 0.9), abdominal fat depot equations (P < 0.00), endoscopic findings according to Los Angeles classification (P < 0.001), symptom severity score (P < 0.00), and serum leptin hormone (43.96 ± 23.50 in group 1 vs. 7.5133 ± 8.18294 in group 2 and 6.98 ± 5.90 in the control group) (P = 0.00). Obesity in general and central (abdominal) obesity specifically has significant impact on clinical and endoscopic severity of GERD. Increased leptin hormone level is associated with clinical and endoscopic severity of GERD. Future trial on larger number of patients is emphasized.

Prognostic role of serum interleukin-18 in Egyptian patients with hepatitis c virus-related hepatocellular carcinoma treated by radiofrequency ablation.

Aim: The aim of this study is to identify the prognostic value of serum interleukin (IL)-18 level in hepatitis C virus (HCV) -related hepatocellular carcinoma (HCC) patients. Materials and Methods: This study was conducted in Tropical Medicine department and HCC unit in Ain Shams University Hospitals. It included 35 patients with HCV associated HCC fit for radio frequency ablation and 20 healthy control subjects. Serum IL-18 level was measured for all participants at the beginning of the study. Patients were followed-up for 1 year then serum IL-18 re-measured at the end of the follow-up period. Results: Pre-intervention serum IL-18 level was significantly higher in patients than healthy control subjects and was associated with bad clinical, laboratory or radiological prognosis. Post follow-up mean value of IL-18 level was significantly lower than pre-intervention level. Conclusion: Higher pre-intervention serum IL-18 level in HCV -related HCC patients level was associated with bad prognosis either clinically, laboratory or radiologically.

Pretreatment and on-treatment indicators of virologic breakthrough of lamivudine therapy in chronic hepatitis B patients: an Egyptian study.

The primary objectives of hepatitis B treatment include improved clinical and histological progression as well as virus eradication. For many years, lamivudine was a first-line therapy for treating hepatitis B virus (HBV) infection. However, its long-term use is associated with high resistance rates (up to 70% after 5 years) due to mutations in the viral YMDD motif. The purpose of this study was to outline factors responsible for the development of viral resistance during long-term lamivudine therapy. Initially, 230 patients receiving lamivudine therapy for chronic hepatitis B (CHB) infection were enrolled in the study. All subjects received follow-ups in the first year to assess viral and biochemical responses. Only 136 and 104 patients received follow-up assessments during the second and third years of treatment, respectively. Viral breakthrough (VBT) occurred in 49 of 230 patients (21.3%). Hepatitis B "e" antigen (HBeAg) status before treatment was significantly associated with VBT in the first 2 years of treatment; however, this effect was not significant in the third year. Pre-treatment HBV DNA levels were predictive of VBT in the HBeAg-positive subgroup after all years of treatment (P = 0.001, P = 0.002, and P = 0.002, respectively). These levels were also predictive in the HBeAg-negative subgroup after 1 year of treatment (P = 0.001). In resource-poor communities, financial concerns drive the selection of antiviral therapy to treat CHB. Lamivudine monotherapy is a relatively cheap and effective treatment to manage CHB. However, consistent follow-ups and treatment modifications appear essential to prevent long-term treatment failure.

Purification and characterization of a thermostable esterase from the moderate thermophile Bacillus circulans.

The thermostable esterase from the moderate thermophile Bacillus circulans was purified to homogeneity using a four-step procedure. Esterase activity was associated with a protein of molecular mass 95 kDa, composed of three identical subunits of 30 kDa. The esterase activity was thermostable with a maximum activity at 55 degrees C using initial rate assay. The half-inactivation temperature was 71 degrees C after a 1-h treatment, which compared favorably to that of other enzymes. Activity at temperatures of 30-37 degrees C was high (about half of maximum), making this new enzyme very attractive for applications in this moderate temperature range. The esterase also showed high activity at a rather alkaline pH (higher than 10). The specificity pattern showed a marked specificity for mid-chain-length fatty acids (3-8 carbon atoms), which classified the enzyme as a carboxylesterase.

D-Cycloserine biases enrichment for auxotrophic mutants of Zymomonas mobilis.

Contrary to its effect on rich medium, D-cycloserine showed no bactericidal effect on Zymomonas mobilis cells cultured on mineral medium. Addition of a mixture of glycine and glutamic acid to the mineral medium restored its bactericidal action. However, mutant enrichments run in these conditions were biased, with mostly methionine mutants isolated. A decrease of the D-cycloserine concentration only reduced the bias.

Isolation and Properties of Mutants of Zymomonas mobilis Deficient in Sugar Assimilation.

An enrichment method using d-cycloserine was designed for the isolation of spontaneous mutants of Zymomonas mobilis deficient in glucose or fructose utilization. The mutants could easily be isolated since they represented 80 to 90% of the population after two and three enrichment cycles. Glucokinase and fructokinase activities in the mutants were affected.

Biosynthetic and growth abnormalities are associated with high-level expression of CFTR in heterologous cells.

An inducible gene amplification system was utilized to study the effects of overexpression of cystic fibrosis transmembrane conductance regulator (CFTR) in vitro. BTS, a monkey kidney cell line expressing a temperature-sensitive simian virus 40 (SV-40) large T antigen was stably transfected at the nonpermissive temperature with a plasmid containing an SV-40 origin of replication and the cDNA for either the wild-type CFTR or the mutant G551D-CFTR. Shift of the isolated cell lines to the permissive temperature resulted in induction and accumulation to high levels of the CFTR plasmid, mRNA, and protein. However, high-level expression of CFTR was transient in both BTS-CFTR and BTS-G551D cells due to a decrease in their respective levels of CFTR mRNA. Because G551D-CFTR only exhibits residual Cl channel activity, this suggests that the observed downregulation with BTS-G551D cells may have been induced by either the physical presence of high amounts of CFTR or some low threshold level of Cl- channel activity. Examination of cell growth properties revealed a correlation between high-level expression of wild-type CFTR and growth arrest of the cells at the G2/M phase. However, similar induction of the G551D-CFTR mutant showed only a slight growth inhibition and little enrichment of cells at the G2/M phase. Cytofluorographic analysis further revealed that BTS-CFTR cells were significantly larger than parental BTS or BTS-G551D cells at all stages of the cell cycle. These results indicate that CFTR overexpression is capable of inducing its own downregulation and that high levels of Cl- channel activity can result in increased cell volume and subsequent cell growth abnormalities.

Overexpression of extracellular sucrase (SacC) of Zymomonas mobilis in Escherichia coli.

The extracellular sucrase (SacC) gene of Zymomonas mobilis was overexpressed in Escherichia coli BL21 using the T7 polymerase expression system. A low cell density induction method was designed to have maximum expression, and the conditions (IPTG concentration, ampicillin addition) were optimised to overexpress to the level of more than 60% of the total cellular protein representing SacC protein.

Molecular cloning and characterization of the extracellular sucrase gene (sacC) of Zymomonas mobilis.

The Zymomonas mobilis gene sacC that encodes the extracellular sucrase (protein B46) was cloned and expressed in Escherichia coli. The gene was found to be present downstream to the already described levansucrase gene sacB in the cloned chromosomal fragment of Z. mobilis. The expression product was different from SacB and exhibited sucrase but not levansucrase activity; therefore, SacC behaves like a true sucrase. Expression of sacC in E. coli JM109 and XL1 was very low; overexpression was observed in E. coli BL21 after induction of the T7 polymerase expression system with IPTG. Subcellular fractionation of the E. coli clone carrying plasmid pLSS2811 showed that more than 70% of the sucrase activity could be detected in the cytoplasmic fraction, suggesting that the enzyme was soluble and not secreted in E. coli. The nucleotide sequence analysis of sacC revealed an open reading frame 1239bp long coding for a 413 amino acid protein with a molecular mass of 46 kDa. The first 30 deduced amino acids from this ORF were identical with those from the N-terminal sequence of the extracellular sucrase (protein B46) purified from Z. mobilis ZM4. No leader peptide sequence could be identified in the sacC gene. The amino acid sequence of SacC showed very little similarity to those of other known sucrases, but was very similar to the levansucrases of Z. mobilis (61.5%), Erwinia amylovora (40.2%) and Bacillus subtilis (25.6%).

1,25-Dihydroxy-vitamin-D3 enhances antiproliferative effect and transcription of TGF-beta1 on human keratinocytes in culture.

Both TGF-beta and 1,25-dihydroxy-vitamin-D3 (1,25(OH)2D3) have been reported to decrease the proliferation of normal human keratinocytes. The effect and expression of TGF-beta in keratinocytes treated with 1,25(OH)2D3 was investigated. Human keratinocytes were grown in the presence of various concentrations of TGF-beta and/or 1,25(OH)2D3 prior to enumeration. TGF-beta, alone, has a half maximal dose of inhibition (ED50) of approximately 750 pg/ml after seven days in culture in Keratinocyte Growth Medium (KGM; Clonetics) supplemented with 1.5 mM calcium. When 1,25(OH)2D3 (10(-7)M) was also added to cultures with various concentrations of TGF-beta, the ED50 shifted an average of 2-fold less. The presence of TGF-beta (10 pg/ml) augmented the potency of 1,25(OH)2D3 by at least 10-fold. In keratinocyte cultures, the antiproliferative effect of the two compounds together is synergistic. In keratinocytes grown for 1 week in the presence of 1,25(OH)2D3 at 10(-6)M, the TGF-beta 1 message increased approximately 5-fold. An increase is detected within 2 hours of exposure to 1,25(OH)2D3. There was only a 50% increase in the levels of TGF-beta 2 and no detection of TGF-beta 3. When keratinocyte cultures were treated with 1,25(OH)2D3 and neutralizing antibodies to TGF-beta, the induced-antiproliferative activity was blocked by more than 50%. The keratinocytes produced more active than latent TGF-beta after growth with high doses of 1,25(OH)2D3.

Effect of 1,25-dihydroxyvitamin D3 on human keratinocytes grown under different culture conditions.

1,25-Dihydroxyvitamin D3 (1,25-(OH)2-D3) is known to decrease the proliferation and increase the differentiation of different cell types including human keratinocytes. The growth and differentiation of keratinocytes in the presence of 1,25-(OH)2-D3 using serum-free media formulations has been described previously. This investigation extends these studies to describe various culture conditions with human foreskin keratinocytes to determine the optimal antiproliferative activity of 1,25-(OH)2-D3. Keratinocytes were plated onto tissue culture dishes using one of three basic serum-free media protocols; a) with no feeder layer in keratinocyte growth medium (KGM); b) onto mitomycin C-treated 3T3 mouse embryo fibroblasts; or c) onto mitomycin C-treated dermal human fibroblasts. The last two protocols utilized Dulbecco's modified Eagle's Medium (DMEM) supplemented with growth factors. Keratinocyte cell growth was greatest in the KGM medium. Although the growth of keratinocytes on either feeder layer was similar, there were differences in the ability of the cells to form envelopes in the presence of 1,25-(OH)2-D3. The addition of hydrocortisone and cholera toxin to the medium also affected the response of the keratinocytes to 1,25-(OH)2-D3. The antiproliferative effect of 1,25-(OH)2-D3 was not altered by varying the extracellular calcium levels from 0.25 to 3 mM. The antiproliferative activity of 1,25-(OH)2-D3 is attenuated in cells at low density. Our results suggest that an optimal condition to investigate the ability of 1,25-(OH)2-D3 to inhibit keratinocyte proliferation is at preconfluent cell density in the presence of KGM supplemented with 1.5 mM calcium without a feeder layer. These conditions are not appropriate for investigating the enhancement of differentiation by 1,25-(OH)2-D3, but can be used to assay other agents that modulate keratinocyte proliferation.

Amylase production by three Lactobacillus strains isolated from chicken crop.

Three amylolytic Lactobacillus strains designated LEM 220, LEM 207 and LEM 202 were isolated from the chicken crop. They belonged to the subgenus Thermobacterium. Strain LEM 220 resembled Lact. acidophilus. Amylase production was more abundant in cells grown in media containing amylopectin or starch than in media containing glucose or maltose. Optimum pH and temperature of the amylase were 5.5 and 55 degrees C respectively. Hydrolysis of amylopectin gave maltose, maltotriose and small amounts of glucose. Stain LEM 207 also resembled Lact. acidophilus, but differed from strain 220. It had a lower amylase activity. Optimum pH and temperature of the amylase were 6.4 and 40 degrees C, respectively, and hydrolysis of amylopectin gave maltose, maltotriose and carbohydrates higher than maltopentaose. Strain LEM 202 was similar to Lact. vitelinus. It had the lowest amylase activity which was increased only in presence of maltose. Amylase properties were similar to those of LEM 220.

[Role of five Lactobacillus strains on carbohydrate degradation in monoxenic chickens]. / Rôle de cinq souches de lactobacilles sur la dégradation des glucides chez le poulet monoxénique.

Five strains of Lactobacillus were isolated in holoxenic roosters; two of these which had an alpha-amylase were inoculated separately into 5 groups of axenic chickens fed the same diet. Some differences among these 5 groups were noted. Lactobacillus proliferation varied between ten and a thousand-fold, depending on the strain, and for the same strain depending on whether the crop, caecum or faeces was examined. Amylolytic lactobacilli in vivo played a role in starch degradation in various ways related to the specific properties of their amylase. Lactic acid production in the crop was higher with the three strains producing the two lactic acid isomers than with the two strains producing only one of the isomers. Finally, monoxenic caecal digestion was different from that of both the axenic and the holoxenic.