Exogenous glutathione protects against gentamicin-induced acute kidney injury by inhibiting NF-κB pathway, oxidative stress, and apoptosis and regulating PCNA

This study was designed, for the first time, to examine the possible nephroprotective effects of exogenous glutathione (EGSH) (100 mg/kg, intraperitoneally) on gentamicin-induced acute kidney injury (GM-induced AKI). EGSH reduced renal histopathological changes, inflammatory cell infiltration, and improved renal dysfunction in rats with AKI. EGSH ameliorated GM-induced renal oxidative stress by promoting the renal activities of catalase, glutathione peroxidase, and superoxide dismutase and diminishing renal malondialdehyde and serum nitric oxide levels. Interestingly, EGSH inhibited intrinsic apoptosis by downregulating Bax and caspase-3 and upregulating Bcl2 in the kidney of rats with AKI. EGSH decreased GM-induced inflammatory response as reflected by a remarkable decrease in the protein expressions of NF-κB-p65, IL-6, TNF-α, and iNOS and a considerable diminish in myeloperoxidase activity. Finally, EGSH markedly declined proliferative cell nuclear antigen (PCNA) protein expression in the animals with AKI. In summary, EGSH alleviated AKI in rats intoxicated with GM, partially by inhibiting oxidative stress, NF-κB pathway, and intrinsic apoptosis and regulating PCNA.

Exogenous glutamine ameliorates diabetic nephropathy in a rat model of type 2 diabetes mellitus through its antioxidant and anti-inflammatory activities

This study aimed to evaluate the effects of glutamine (Gln) on diabetic nephropathy and other complications in a rat model of type 2 diabetes mellitus. Streptozotocin/nicotinamide induced diabetic rats were enrolled as an animal model of type 2 diabetes mellitus. Animals were divided into control, diabetic, and Gln (1000 mg/l in drinking water, eight weeks) treated diabetic groups. Gln alleviated renal inflammatory and oxidative stress biomarkers (tumour necrosis factor-alpha, interleukin 6, glutathione peroxidase, total superoxide dismutase, and glutathione), decreased serum uric acid and creatinine, and restored renal histopathological changes (glomerular volume, sclerosis, and leukocyte infiltration). Additionally, Gln ameliorated other complications, including systemic oxidative stress (serum malondialdehyde and nitric oxide, serum and liver glutathione, glutathione peroxidase, and total superoxide dismutase, and liver catalase), insulin resistance, hyperglycaemia, and hyperlipidaemia. Collectively, Gln attenuates diabetic nephropathy and other complications in type 2 diabetes mellitus in rats through its antioxidant and anti-inflammatory activities.

The effect of ascorbic acid and bio fertilizers on basil under drought stress

Evaluate the effect of ascorbic acid application and coexistence of Mycorrhiza fungus and Azospirillium on basil (Ocimum basilicum L.) under drought stress. This experiment was performed as a split factorial in a randomized complete block design with three replications in the crop year 2017-2018 in Shahriar, Iran. In this experiment, irrigation was the main factor in three levels, including drought stress based on 40-70-100 mm from the evaporation pan of class A. Biofertilizer including growth-promoting bacteria (Azospirillium) and mycorrhiza fungus in four levels, including a(Non-consumption) B (Seeds of growth-promoting bacteria (Azospirillium)) C (Consumption of mycorrhiza fungus as seeds) D (Concomitant use of growth-promoting bacteria Azospirillium with mycorrhiza fungi as seeds) and ascorbic acid in two levels of foliar application, including A (Absence Application of ascorbic acid) and B (Application of ascorbic acid (two days after irrigation treatment)) was considered as a factorial factor. The results showed that the highest biological yield was obtained in drought stress of 40 mm and application of biological fertilizers in the form of mycorrhiza application with an average of 3307.1 kg/ha, which was about 70% more than 100 mm evaporation stress and no application of biological fertilizer. The use of ascorbic acid under drought stress conditions improved by 10%, the essential oil using ascorbic acid evaporated under drought stress conditions of 100 mm. As a general conclusion, the use of ascorbic acid and Mycorrhiza + Azospirillium biological fertilizer improved the quantitative and qualitative characteristics of basil under drought stress.

A Thyroid Stimulating Hormone Reference Range: Iranian Thyroid Cohort study

Background:

Current reference values for thyroid function tests are derived from data from different ethnicities and geographical areas. In this article, we aim to select criteria from the guidelines proposed by the National Academy of Clinical Biochemistry (NACB) and to determine the TSH and T4 reference limits in the iodine-sufficient area of Isfahan, a metropolitan city in Iran.

Materials and methods:

This study was conducted within the framework of “Isfahan Thyroid Study (ITS)”, an ongoing prospective cohort that started in 2006 (n=2523) until 2011 (n=711) and included participants above the age of twenty. We measured TSH, total T4, thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TgAb).

Results:

Recruitment was based on the NACB criteria, 1899 participants were included in 2006(58.5% male) and 377 in 2011(62.3% male). The mean± SD age was 39.66 ±12.71 and 48.96±12.35 years in 2006 and 2011, respectively. The mean± SD for TSH was 2.0±1.19 and 2.11±1.11 mU/L and T4 was 6.67±1.47 and 8.3±2.95 μg /dl in 2006 and 2011, respectively. In 2006, the 2.5th percentile of serum TSH levels was 0.4 mU/L (males: 0.4 mU/L, females: 0.5 mU/L) and the 97.5th percentile of serum TSH was 4.96 mU/L (males: 4.72 mU/L, females: 5. 3 mU/L). In 2011, the 2.5th percentile of serum TSH levels was 0.7 mU/L (males: 0.6 mU/L, females: 0.77 mU/L) and 97.5th percentiles of serum TSH was 4.9 mU/L (males: 5.7 mU/L, females: 5. 57 mU/L).

Conclusion:

This study determined age and sex specific TSH and T4 reference ranges in the Isfahanian population, which could theoretically enable clinicians to classify patients more accurately. (www.actabiomedica.it)

Cinnamic acid ameliorate gentamicin-induced liver dysfunctions and nephrotoxicity in rats through induction of antioxidant activities

This study was the first to evaluate the possible protective effects of cinnamic acid (CA) against Gentamicin (GM) induced liver and kidney dysfunctions in rats. Adult male Wistar rats were randomly assigned to 4 equal groups (n = 8): Control group (saline, 0.5 ml/day), CA group (CA, 50 mg/kg/day), GM group (GM, 100 mg/kg/day), and GM + CA group (100 & 50 mg/kg/day). Following 12 days of treatments, blood and 24 h urine samples were collected and kidneys were taken out for biochemical, histopathological, and molecular studies. Following CA treatment, renal function markers and transaminases activities including serum urea (59.92%) and creatinine (50.41%), protein excretion rate (43.67%), and serum activities of aspartate aminotransferase (AST) (54.34%) and alanine aminotransferase (ALT) (47.26%) significantly reduced in the treated group as compared with the GM group (P < 0.05). Also, CA could significantly ameliorate the levels of triglyceride (29.70%), cholesterol (13.02%), very low-density lipoprotein (29.69%) and high-density lipoprotein-cholesterol (7.28%). CA could also attenuate oxidative stress through a decrease of serum malondialdehyde (MDA) (50.86%) and nitric oxide (NO) (0.85%) and an increase of renal catalase (CAT) (196.14%) and glutathione peroxidase (GPX) activities (45.88%) as well as GPX mRNA expression (44.42-fold) as compared with the GM group (P < 0.05). Moreover, histopathological evaluations revealed attenuated tubular damages and reduced inflammatory cellular infiltration in CA treated animals. Overall, CA alleviates GM-induced nephrotoxicity and alterations in transaminases activities in rats through its antioxidant activities.

Evaluation of The effects of Anti-Inflammatory Drugs on Local and Systemic manifestations of snakebite: A cross-sectional study

Although the predominant treatment for snakebite is the antivenom, other treatments are also considered. We studied the effects of single or multiple-doses of anti-inflammatory drugs on local, systemic and laboratory findings of the snakebite victims. In this cross-sectional study, 101 patients (90 male: 89.1%) with snakebite envenomation who were admitted to the Medical Toxicology Center of Khorshid Hospital, Isfahan, Iran, were investigated. One group (35 patients: 34.7%) received a single-dose of anti-inflammatory drugs containing chlorpheniramine (10mg intramuscular injection) with cimetidine (200mg intravenous injection) or ranitidine (50mg intravenous injection) plus hydrocortisone (100mg intravenous injection). The other 55 patients (54.5%) received multiple doses of the same drug combination every 8hr until the symptoms resolved. Local, systemic symptoms and laboratory findings on admission, and during 24hr and 48hr of admission, were recorded. The frequency of the localized signs of inflammation (p=0.03), swelling (p<0.001) and bruising (p<0.001) showed a significant difference between the two treated groups. In addition, the recovery time in the patients who received multiple doses was faster (p<0.001). There was no significant difference in any of the systemic signs, laboratory findings or the outcome between the patients in the various groups during hospitalization. Our data indicate that the administration of multiple doses of anti-inflammatory drugs had a greater effect on reducing local symptoms of snakebite including inflammatory manifestations.

D-Limonene Alleviates Acute Kidney Injury Following Gentamicin Administration in Rats: Role of NF-κB Pathway, Mitochondrial Apoptosis, Oxidative Stress, and PCNA

Clinical application of gentamicin (GM) is well known to be associated with the development of acute kidney injury (AKI). This study was the first to investigate the possible protective effects of D-limonene (D-lim) on AKI following GM administration in rats. 32 rats arranged in four groups (n = 8): (1) the control group received saline intraperitoneally (0.5 ml/day) and orally (0.5 ml/day), (2) the D-lim group received D-lim (100 mg/kg) orally and saline (0.5 ml/day) intraperitoneally, (3) the GM group received GM (100 mg/kg/day) intraperitoneally and saline (0.5 ml/day) orally, and (4) the treated group received intraperitoneal GM (100 mg/kg) and oral D-lim (100 mg/kg). All treatments were performed daily for 12 consecutive days. Results revealed that D-lim ameliorated GM-induced AKI, oxidative stress, mitochondrial apoptosis, and inflammation. D-lim showed nephroprotective effects as reflected by the decrease in serum urea and creatinine and improvement of renal histopathological changes. D-lim alleviated GM-induced oxidative stress by increasing the activities of renal catalase, serum and renal glutathione peroxidase, and renal superoxide dismutase and decreasing renal malondialdehyde and serum nitric oxide levels. Intriguingly, D-lim suppressed mitochondrial apoptosis by considerably downregulating Bax and caspase-3 (Casp-3) mRNA and protein expressions and markedly enhancing Bcl2 mRNA and protein expressions. Furthermore, D-lim significantly decreases GM-induced inflammatory response through downregulation of NF-κB, IL-6, and TNF-α mRNA and/or protein expressions and decrease in renal myeloperoxidase activity. Finally, D-lim remarkably downregulated PCNA protein expression in the treated group compared with the GM group. In brief, this study showed that D-lim alleviated AKI following GM administration in rats, partially through its antioxidant, anti-inflammatory, and antiapoptotic activities as well as downregulation of PCNA expression.

Thrombotic Thrombocytopenic Purpura with Conjunctivitis in a Patient with Coronavirus Disease 2019 Infection

An 81-year-old female presented with a loss of consciousness and a history of fever, dry cough, dyspnea, and conjunctivitis during 5 days ago. On initial physical examination, the laboratory examination revealed high levels of lactate dehydrogenase and creatinine concomitant severe thrombocytopenia. Moreover, the peripheral blood smear showed schistocytes 3%, suggesting thrombotic thrombocytopenic purpura (TTP). A ground-glass pattern was reported in the high-resolution computed tomography of the lung. A positive polymerase chain reaction was reported for coronavirus disease 2019 (COVID-19). After initiating treatment for COVID-19, the patient received fresh frozen plasma and 24-h electrocardiogram monitoring in the emergency department. As the patient was being prepared for transfer to another hospital for plasmapheresis treatment, cardiac arrest occurred again, and the patient passed away. This study highlights the atypical behavior of this virus over the course of the disease including TTP with conjunctivitis, which could vary from case to case.

Severity of the metabolic syndrome as a predictor of prediabetes and type 2 diabetes in first degree relatives of type 2 diabetic patients: A 15-year prospective cohort study

BACKGROUND

Type 2 diabetes mellitus (T2DM) has high morbidity and mortality worldwide, therefore there is of paramount importance to identify the risk factors in the populations at risk early in the course of illness. A strong correlation between severity of metabolic syndrome (MetS) and HbA1c, fasting insulin and insulin resistance has been reported. Accordingly, the MetS severity score (or MestS Z-score) can potentially be used to predict the risk of T2DM progression over time.

AIM

To evaluate the association the of MestS Z-score in first degree relatives (FDRs) of T2DM with the risk of prediabetes and type 2 diabetes in future.

METHODS

A prospective open cohort study was conducted between 2003-2018. At baseline, the sample comprised of 1766 FDRs of patients with T2DM who had a normal glucose tolerance test. Relative risk (RR) and 95% confidence interval were calculated based on logistic regression. The receiver-operator characteristic analysis and area under the curve based on MetS Z-score were used to evaluate the risk of prediabetes and diabetes among the FDR population.

RESULTS

Baseline MetS Z-scores were associated with the its latest values (P < 0.0001). Compared with individuals who were T2DM free at the end of follow up, those who developed T2DM had higher MetS Z-score at baseline (P < 0.001). In multivariable logistic regression analyses for every unit elevation in MetS Z-score at the baseline, the RR for developing future T2DM and prediabetes was (RR = 1.94, RR = 3.84), (RR = 1.5, RR = 2.17) in total population and female group, respectively (P < 0.05). The associations remained significant after adjusting the potential confounding variables. A cut off value of 0.97 and 0.94 was defined in the receiver-operator characteristic curve based on the MetS Z-score for differentiating female patients with diabetes and prediabetes from the normal population, respectively.

CONCLUSION

The MetS Z-score was associated with an increased risk of future T2DM. Appropriate interventions at earlier stages for preventing and attenuating MetS effects may be considered as an effective strategy for FDR as at-risk population.

Dyspnea and Cough: A Rare Report of the Kimura Disease

BACKGROUND

Known as a rare disease, Kimura disease is a chronic, allergic and inflammatory process. It may overlap other allergic conditions, as well.

CASE PRESENTATION

This study is going to present a 36-year-old woman, with cough, dyspnea and bone pain. Other differential diagnoses were excluded during the investigations. The definite diagnosis was made by excisional biopsy and pathological investigations.

CONCLUSION

This was a rare medical condition with remarkable diagnostic challenge.

The Protective Role of Gallic Acid Pretreatment On Renal Ischemia-reperfusion Injury in Rats

BACKGROUND

Renal ischemia-reperfusion injury (RIR) occurs when there is a temporary restriction of blood flow to the kidneys followed by an influx of blood, re-oxygenating the tissues. This occurs as a severe complication of major surgery. This process causes significant damage to the tissues and is responsible for the development of acute kidney injury (AKI), a life-threatening condition with high mortality rates. Here, we evaluated the potential protective effects of the antioxidant, gallic acid (GA), on RIR in an in vivo rat model.

METHODS

Adult male Sprague Dawley rats were randomly divided into three groups: group 1 (control, n = 8), group 2 (Ischemia-reperfusion (IR) with no-treatment, n = 7), and group 3 (IR + daily GA 100 mg/kg i.p, n = 7). The abdomens of the rats in the control group were opened during the surgical procedure, then sutured closed. GA pretreatment began daily 15 days prior to inducing RIR. To induce RIR, the umbilical arteries were obstructed on both sides and clamped with mild pressure for 45 min. Following the 45 min ischemia, the clamps were removed to allow for the induction of reperfusion. The reperfusion phase was 24 hours.

RESULTS

Following IR, the serum levels of urea and creatinine significantly increased compared to the controls. Pretreatment with GA was observed to reduce urea and creatinine levels following IR. However, this decrease was not statistically significant. The serum and renal levels of malondialdehyde (MDA) in the IR group was significantly elevated compared to the control group. Conversely, glutathione (GSH) levels and the activity of glutathione peroxidase (GPX) significantly decreased in the IR group compared to controls. Our findings show GA pretreatment to significantly improve the levels of renal MDA, serum GSH, and GPX activity following RIR.

CONCLUSION

Our findings highlight the protective role for GA in mitigating the damage caused by RIR and its applications as a potential treatment.

Neuronal autoantibodies in focal epilepsy with or without mesial temporal sclerosis

Background: This study was designed to investigate the difference in the prevalence of neuronal autoantibodies in patients diagnosed with established temporal lobe epilepsy (TLE) of unknown cause with mesial temporal sclerosis (MTS) and patients with TLE without MTS. Methods: In an observational cohort study design, we included thirty-three consecutive adult patients and divided them into two groups with and without MTS. We evaluated anti-neuronal and nuclear antibodies with immunofluorescence (IF) and enzyme-linked immunosorbent assay (ELISA), respectively. Results: From the thirty-three consecutive patients with epilepsy 17 (51.1%) had MTS of which 12 had unilateral and 5 had bilateral MTS. No significant difference was detected between seropositive and seronegative patients in MTS versus non-MTS groups. The studied autoantibodies were present in 16 patients, including gamma-aminobutyric acid receptor (GABA-R) antibodies being the most common in 11 (33.3%), followed by N-methyl-D-aspartate receptor (NMDA-R) in 2 (6.1%), glutamic acid decarboxylase receptor (GAD-R) in 1 (3.0%), anti-phospholipid (APL) antibody in 1 (3.0%), CV2 in 1 (3.0%), Tr in 1 (3.0%), recoverin in 1 (3.0%), and double-stranded deoxyribonucleic acid (dsDNA) antibody in 1 (3.0%) of our patients with focal epilepsy. In both MTS and non-MTS groups, eight patients were positive for antibodies; four patients were positive for GABA in the MTS group and seven for GABA in the non-MTS group. Conclusion: Neuronal antibodies were presented in half of patients with focal epilepsy, GABA antibody being the leading one. No specific magnetic resonance imaging (MRI) findings were found in the seropositive group. Our results suggest that screening for relevant antibodies may enable us to offer a possible treatment to this group of patients.

Glutathione ameliorates liver markers, oxidative stress and inflammatory indices in rats with renal ischemia reperfusion injury

Introduction: Glutathione (GSH) protects the tissue and cell from oxidative injury. Objectives: In the current study, we investigated the possible effects of GSH on liver markers, oxidative stress and inflammatory indices in rat with renal ischemia reperfusion (RIR) injury. Materials and Methods: Twenty-four adult male Wistar rats were divided into 3 groups (n=8). Group I (the control group), group II (the RIR group) received saline (0.25 mL/d, intraperitoneally; i.p.), group III as the RIR group that received GSH (100 mg/kg/d, i.p.). The treatment with saline or GSH began daily 14 days before RIR induction. RIR was induced by clamping renal pedicles for 45 minutes and 24 hours of reperfusion. Results: RIR significantly increased the serum level of nitric oxide (NO), the serum activities of aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma-glutamyltransferase (GGT), the serum and renal levels of malondialdehyde (MDA), and the serum activity of myeloperoxidase (MPO). However, RIR significantly decreased the serum and renal levels of GSH, serum paraoxonase 1 (PON1) activity, and the serum and renal activities of catalase (CAT) and glutathione peroxidase (GPX). GSH administration could significantly improve the serum activities of AST, GGT, MPO, GPX and PON1 and serum levels of NO, renal MDA, GSH levels, and serum and also renal CAT activities. Conclusion: Our study indicated that GSH administration ameliorated RIR injury in rats by improving the activities of liver markers and antioxidant enzymes, the levels of MDA, NO, GSH and MPO activity.

Area under the curve during OGTT in first-degree relatives of diabetic patients as an efficient indicator of future risk of type 2 diabetes and prediabetes

OBJECTIVE

To establish whether the area under the curve of an OGTT has a predictive role in identifying prediabetic and diabetic subjects among first-degree relatives (FDR) of patients with diabetes mellitus type 2 (DM).

DESIGN, PATIENTS AND MEASUREMENTS

In a population-based cohort study, 766 FDR of diabetic patients with a normal glucose tolerance test (NGT) completed a 2-hour OGTT. They were followed up for 7 years and classified according to the American Diabetes Association criteria into: NGT, impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and DM. Relative risk (RR) and 95% confidence intervals (95%CI) were calculated based on logistic regression. Receiver operator characteristic (ROC) analysis along with AUC at different intervals and at time points during the OGTT was used to evaluate the risk of prediabetes and diabetes.

RESULTS

Twenty-three subjects (3%) developed type 2 DM, 118 (29.3%) IFG, 81 (11.5%) IGT and 544 (71%) subjects remained NGT. AUC and mean difference of glucose in all high-risk groups demonstrated significant differences in both intervals and time points when compared to the NGT group. The cut-off values during OGTT to predict prediabetes and diabetes was determined as blood glucose more than 7.2 and 7.8 mmol/L at 30 and 60 minutes, respectively. The time point 60 has the highest predictive role for the development of diabetes, alone, and improved the performance of a prediction model containing multiple important clinical risk factors.

CONCLUSION

The data suggest that the glycaemic response to an OGTT may predict the risk of development of diabetes in first-degree relatives of DM patients.

The TSH levels and risk of hypothyroidism: Results from a population based prospective cohort study in an Iranian adult's population

OBJECTIVE

The aim of current study was to assess the relationship between serum TSH levels and hypothyroidism risk in the euthyroid population.

METHODS

In a population-based cohort study, a total of 615 individuals with a normal baseline TSH, from of total population (n=2254) in 2006, were followed up for 6years. TSH, total T4, thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TgAb) were measured. The relative risk (RR) and 95% confidence interval (95%CI) were calculated based on logistic regression. The Receiver Operating Characteristic (ROC) analysis along with area under the curve (AUC) was used to prediction of future hypothyroidism.

RESULTS

TSH level in 2006 was a significant predictor for overt hypothyroidism, in the total population (RR=3.5) and female (RR=1.37) (all, P value<0.05). A cutoff value of TSH at 2.05mIU/L [AUC: (CI95 %), 0.68 (0.44-0.92; P=0.05)] was obtained for differentiating the patients with overt hypothyroidism from euthyroid. However, this cut off was not observed when we included only negative TPO and TgAbs people in 2006. The RR of hypothyroidism increased gradually when TSH level increased from 2.06-3.6mIU/L to >3.6mIU/L in the total population and both sexes. In women, the risk of overt hypothyroidism was significantly higher in subjects with TSH above 3.6 than those subject with THS levels≤2.05 [RR: (CI95 %), 20.57(2.-207.04), P value<0.05].

CONCLUSION

A cutoff value of TSH at 2.05mIU/L could predict the development of overt hypothyroidism in future. However, it was not applicable for people with negative TPOAb and negative TgAb.

[Primary breast sarcomas: About 30 cases treated at Salah-Azaiez institute in Tunisia]

PURPOSE

To identify retrospectively prognostic factors of primary breast sarcoma and review its treatment modalities.

MATERIALS AND METHODS

This is a descriptive study on 30 cases of primary breast sarcoma. We carried out a univariate and multivariate analysis correlating clinical, pathological and therapeutic parameters with disease-free survival and overall survival.

RESULTS

The mean age was 46.8 years. The mean tumour size was 10cm. The 30 cases were 18 phyllodes sarcomas, eight angiosarcomas, three liposarcomas and a case of granulocytic sarcoma. Sixteen patients had adjuvant radiotherapy and only seven patients received adjuvant chemotherapy. The median follow-up was 64 months. Overall survival rates at 3 and 5 years were 49.1% and 33.7%. Disease-free survival rates at 3 and 5 years were 22.8% and 15.2% respectively. The analytical study of the following parameters: tumour size and presence or absence of node or distant metastases, showed no correlation with overall survival nor with disease-free survival. Furthermore, adjuvant radiotherapy did not improve overall survival (P=0.298; hazard ratio [HR]=1 [0.982-1.04]) nor disease-free survival (P=0.61; HR=0.942 [0.862-1.029]). By univariate analyses, we identified a correlation between overall survival, surgical margins (>1cm) (P=0005; HR=3.4 [1.217-9.919]) and tumour necrosis (P=0.028; HR=0.099 [0.014-0.682]). We did not find any independent prognostic factor by multivariate analysis.

CONCLUSION

The prognosis of primary breast sarcoma seems to depend essentially on optimal surgical excision (margin over 1cm). The only potential histological parameter correlated with the prognosis is the presence of tumour necrosis. The histological subtype should not be considered as a prognostic marker for overall or disease-free survival in patients with primary breast sarcoma.

Protein Hydrolysates and Biopeptides: Production, Biological Activities, and Applications in Foods and Health Benefits. A Review

In recent years, a great deal of interest has been expressed regarding the production, characterization, and applications of protein hydrolysates and food-derived biopeptides due to their numerous beneficial health effects. In this regard, research is mainly focused on investigating the therapeutic potential of these natural compounds. Based on their amino acids composition, sequences, hydrophobicity, and length, peptides released from food proteins, beyond their nutritional properties, can exhibit various biological activities including antihypertensive, antioxidative, antithrombotic, hypoglycemic, hypocholesterolemic, and antibacterial activities among others. Protein hydrolysates are essentially produced by enzymatic hydrolysis of whole protein sources by appropriate proteolytic enzymes under controlled conditions, followed by posthydrolysis processing to isolate desired and potent bioactive peptides from a complex mixture of active and inactive peptides. Therefore, because of their human health potential and safety profiles, protein hydrolysates and biopeptides may be used as ingredients in functional foods and pharmaceuticals to improve human health and prevent diseases. In this review, we have focused on the major variables influencing the enzymatic process of protein hydrolysates production. The biological properties of protein hydrolysates will be described as well as their applications in foods and health benefits.

Wool-waste valorization: production of protein hydrolysate with high antioxidative potential by fermentation with a new keratinolytic bacterium, Bacillus pumilus A1

AIMS

Wool, a recalcitrant waste mainly composed of keratin, constituted a serious problem for the environment and was not effectively valorized. This study reported the optimization of wool-waste biodegradation by a new keratinolytic bacterium Bacillus pumilus A1. The in vitro digestibility and the antioxidant potential of wool protein hydrolysate (WPH) were also investigated.

METHODS AND RESULTS

The antioxidant potential of WPH was evaluated using in vitro antioxidant assays, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, reducing power and metal (Fe(2+)) chelating activity. Cultivation on 50 g l(-1) of wool for 2 days, at 45°C and at initial pH of 10, resulted in maximum production of amino acids and peptides (39.7 g l(-1)). WPH presented a very high in vitro digestibility (97%) as compared with that of the untreated wool (3%).

CONCLUSIONS

The keratin present into the wool-waste was completely solubilized. Interestingly, WPH presented an important DPPH radical-scavenging activity with an IC50 value of 0.14 ± 0.01 mg ml(-1).

SIGNIFICANCE AND IMPACT OF STUDY

WPH would be a very useful source of protein and antioxidants in animals' diets.

Central venous saturation is not an alternative to mixed venous saturation during cardiopulmonary bypass in coronary artery surgery patients

BACKGROUND

To evaluate the correlation and agreement between central venous saturation (ScvO(2)) and mixed venous saturation (SvO(2)) during cardiopulmonary bypass.

METHODS

Twenty-two consecutive patients scheduled for coronary artery surgery were prospectively included. Paired measurements of ScvO(2) and SvO(2) were performed 5 minutes after aortic cross-clamping, after each cardioplegia dose and after de-clamping of the aortic cross-clamp. ScvO(2) and SvO(2) were measured, respectively, by a fibreoptic catheter in the superior vena cava and on blood samples from the venous return line of the extracorporeal circuit, using a blood gas analyser

RESULTS

Ninety-five paired measurements of venous saturation were obtained. Correlation between the measurements was associated with an r = 0.55. The mean bias was 2.2 [Limits of agreement: -13.6%, +18%]. Changes in oxygen saturation over time showed an r = 0.4 and a mean bias of 0.2 [Limits of agreement: -17.9%, +18.3%]. Multivariate analysis identified the oxygen consumption index as the only factor explaining this variability.

CONCLUSIONS

Although mean biases between the measurements were low, limits of agreement were too large to provide a clinically acceptable estimation of SvO(2) by ScvO(2) in these conditions. Variations in regional oxygen consumption seem to be the main factor worsening the relationship.

Production and purification of a calcium-dependent protease from Bacillus cereus BG1

The production and purification of a calcium-dependent protease by Bacillus cereus BG1 were studied. The production of the protease was found to depend specifically on the calcium concentration in the culture medium. This suggests that this metal ion is essential for the induction of protease production and/or stabilisation of the enzyme after synthesis. The calcium requirement is highly specific since other metal ions (such as Mg(2+) and Ba(2+), which both activate the enzyme) are not able to induce protease production. The most appropriate medium for growth and protease production comprises (g L(-1)) starch 5, CaCl(2) 2, yeast extract 2, K(2)HPO(4) 0.2 and KH(2)PO(4) 0.2. The protease of BG1 strain was purified to homogeneity by ultrafiltration, heat treatment, gel filtration on Sephacryl S-200, ion exchange chromatography on DEAE-cellulose and, finally, a second gel filtration on Sephacryl S-200, with a 39-fold increase in specific activity and 23% recovery. The molecular weight was estimated to be 34 kDa on SDS-PAGE. The optimum temperature and pH of the purified enzyme were determined to be 60 degrees C and 8.0, respectively, in 100 mM Tris-HCl buffer + 2 mM CaCl(2).

Treatment of saline wastewaters from marine-products processing factories by activated sludge reactor

An activated sludge reactor, operated at room temperature (20-30 degrees C) was used to treat saline wastewaters generated by marine-products industries. The system was operated continuously and the influence of the organic loading rates (OLRs), varying from 250 to 1000 mg COD l(-1) day(-1), on chemical oxygen demand (COD) removal was investigated. The system, inoculated with NaCl-acclimated culture, removed up to 98% and 88% of the influent COD concentrations at OLRs of 250 and 1000 mg COD L(-1) day(-1), respectively. Since the organic pollution is essentially composed of proteins, microorganisms, which produced proteolytic enzymes, were isolated from the activated sludge culture. One bacterium with the highest protease activity, identified as Bacillus cereus, was chosen for protease production in fishery wastewaters of different concentrations containing combined heads and viscera powder. Protease synthesis was strongly enhanced when cells were cultivated in two times diluted fishery wastewaters. The enhancement of protease synthesis could have been due to the presence in effluent of organic matters or salts, which stimulated the growth of the strain and protease production.

Effects of partial stone removal on the co-composting of olive-oil processing solid residues with poultry manure and the quality of compost

Full scale composting studies were performed with stoned (SEOOPSW) and non stoned exhausted olive-oil processing solid waste (NSEOOPSW) mixed with 20% poultry manure to reach a C/N ratio of around 30 and to improve the chemical and microbiological properties of the end products. The experiment was performed on two windrows (3 m wide, 2.5 m high and 10 tonne weight) to investigate the effects of stone removal and poultry manure addition on composting process efficiency and on the quality of composts. The partially stone removal operation reduced the total composting time by at least one month compared with the untreated waste. The addition of poultry manure improved the chemical quality of the end product, as shown by the doubling of the nitrogen concentration after four months composting together with the increased amount of P and K. Compost from stoned exhausted olive-oil processing solid waste had higher levels of cation exchange capacity (CEC) and humic acid content with a lower [FA/HA] ratio indicating a high polymerisation level. Agronomic field test showed that both composts are not phytotoxic. When applied at the rate of 40 tonne ha(-1) to a potato culture, they produced approximately the same yield (46 and 48.5 tonne ha(-1)) but they acted differently in terms of plant development. Compost produced from the NSEOOPSW acted more positively on the stem length (84.1 against 77.6 cm) and on leaf weight (354 against 238 g), whereas compost from the SEOOPSW more positively affected tuber sizes (76% large grade compared to 55%).

Production of protease by Bacillus subtilis grown on sardinelle heads and viscera flour

Fish flours from Sardinelle (Sardinella aurita) were prepared and tested for protease production by Bacillus subtilis. Protease synthesis was strongly induced when cells were grown in media containing only a combined head and viscera preparation. Sardinelle heads and viscera flour enhanced protease production up to 100% more than commercial peptones. The enhancement could have been due to a high lipid content, which might have contained nutritional factors acting as inducers, since defatting fish meal led to a decrease in protease production.

[Preparation and testing of Sardinella peptones: application to lipase production by Staphylococcus sp]

Production of lipase by Staphylococcus sp. in media containing fish peptones from sardinelle (Sardinella aurita) prepared in the laboratory was studied. Lipase production is strongly affected by lipids present in fish flours. Fish peptones prepared from dIgresed whole flesh was an excellent substrate for lipase production. A comparison of lipase production in media containing fish peptones or high quality commercial peptones indicated that fish peptones enhanced enzyme formation.

Immobilized and free cell continuous cultures of a recombinant E. coli producing catechol 2,3-dioxygenase in a two-stage chemostat: improvement of plasmid stability

The immobilization of recombinant strains of E. coli W3110/pTG205 in K-carrageenan gel beads improves the plasmid stability during continuous cultures in the absence of selection pressure. Since, xyl E gene (which encodes catechol 2,3-dioxygenase from Pseudomonas putida) transcription is controlled by the trp promoter, the effects of tryptophan (repressor) and 3 beta-indolyl acrylic acid (derepressor) on pTG 205 stability and enzyme production have been studied in both free and immobilized cell cultures. A two-stage continuous culture system running for 150 h is described. In the first stage an immobilized culture is performed in the presence of tryptophan with a significant plasmid stability. The cells released from the gel beads are continuously transferred in the second stage reactor where expression is induced by 3 beta-indolyl acrylic acid. In these conditions an efficient production of catechol 2,3-dioxygenase is observed.

Stability fluctuations of plasmid-bearing cells: immobilization effects

The maintenance of the plasmid vectors pTG201 and pTG206 (which both carry the Pseudomonas putida xylE gene) and pB lambda H3 in Escherichia coli hosts was studied in free and immobilized continuous cultures. pTG201, containing the strong lambda PR promoter, was more quickly lost than plasmid pTG206, containing the tetracycline resistance gene promoter. The instability of pTG201 seems to be related to high expression of the cloned xylE genet. Fluctuations in the proportion of pTG201-containing cells were observed in the free system, suggesting the appearance of adaptive descendants (with and without plasmid) from the initial strains. The loss of plasmid vectors from E. coli cells and the fluctuations in the proportion of plasmid-containing cells could be prevented by immobilizing plasmid-containing bacteria in carrageenan gel beads.

Alteration of the specificity of PvuII restriction endonuclease

The restriction endonuclease PvuII which cleaves the sequence CAGCTG, at the position indicated by the arrow, was found to decrease its substrate specificity in the presence of organic solvents. Thirty-three sites, that we have named PvuII sites, were identified on the nucleotide sequence of pBR322 DNA. The new recognition sequences cleaved in pBR322 DNA, at the positions indicated by the arrows, were shown to be AAGCTG, GAGCTG, CNGCTG, CANCTG, CAGNTG, CAGCNG, CAGCTC and CAGCTT. (TAGCTG and the complementary sequence CAGCTA are not present in pBR322 DNA). From these recognition sequences, we deduced that PvuII activity recognizes and cleaves degenerate sequences which differ from the standard PvuII sequence CAGCTG at only one of the recognition site. Any substitution can occur at any one of the six positions in the hexanucleotide sequence. The optimum incubation medium for PvuII activity was found to be: 10-50 mM Tris-HCl, pH 8.5, 12-15 mM MgCl2, 50 mM NaCl, 10% ethanol + 10% dimethylsulfoxide (DMSO).