Recent insights into carrageenan-based bio-nanocomposite polymers in food applications: A review.

Nanotechnology has proven as progressive technology that enables to contribute, develop several effective and sustainable changes in food products. Incorporating nanomaterials like TiO2, SiO2, Halloysite nano clay, Copper sulfide, Bentonite nano clay, in carrageenan to develop innovative packaging materials with augmented mechanical and antimicrobial properties along with moisture and gas barrier properties that can produce safe and healthy foods. Intervention of carrageenan-based bio-nanocomposites as food packaging constituents has shown promising results in increasing the shelf stability and food quality by arresting the microbial growth. Nanomaterials can be incorporated within the carrageenan for developing active packaging systems for continuous protection of food products under different storage environments from farm to the fork to ensure quality and safety of foods. Carrageenan based bio nanocomposite packaging materials can be helpful to reduce the environmental concerns due to their high biodegradability index. This review gives insight about the current trends in the applications of carrageenan-based bio nanocomposites for different food packaging applications.

Oral versus intubated feeding and the effect on glycaemic and insulinaemic responses, gastric emptying and satiety.

Cephalic phase responses (CPR) are important in early initiation of digestion and maximal absorption of nutrients prior to ingestion. Bypassing CPR has been shown to have consequences on metabolic responses that may influence satiety. The aim of this study was to investigate if using gastric intubation to bypass oro-pharyngeal and oesophageal exposure would reduce CPR including insulin and blood glucose and whether these impact on gastric emptying and satiety. Ten male subjects were tested on 2 occasions, 3-7 days apart after an overnight fast, in randomized order. Subjects were cannulated and intubated with a gastric tube for both tests. For test one, subjects ate 400 ml soup with a spoon and for test two the soup was infused into the stomach at an equivalent rate. Subsequently measurements of glycaemic (GR) and insulinaemic responses (IR) from cannula samples, breath samples for measurement of gastric emptying using the [(13)C] sodium acetate breath test and visual analogue scales (VAS) for satiety were taken over 180 min. There were differences in IR over the first 15 min (Oral: 169.0 ± 22.1; Gastric 124.1 ± 18.8; t(9) = 2.67; p = 0.028) but no difference in GR. There were differences in gastric emptying half time (Oral: 85.0 ± 2.7; Gastric 79.4 ± 3.3; t(9) = 2.40; p = 0.04) and ascension time (Oral: 68.2 ± 2.2; Gastric 64.0 ± 2.2; t(9) = 2.57; p = 0.03) with food taking longer to empty from the stomach on the Oral test day than on the Gastric test day. There was no significant difference in the satiety ratings. This study demonstrated that bypassing oro-pharyngeal and oesophageal exposure decreases the normal physiological CPR with detriment to IR and gastric emptying.

A randomized double-blind study to evaluate efficacy and safety of epidural magnesium sulfate and clonidine as adjuvants to bupivacaine for postthoracotomy pain relief.

BACKGROUND: The aim of the study was to compare postoperative pain relief in patients undergoing an elective thoracotomy with thoracic epidural analgesia using single shot magnesium and clonidine as adjuvants to bupivacaine. METHODS: In a randomized prospective study, 60 patients of American Society of Anesthesiologists physical status I-III of either sex, between 20 and 60 years undergoing elective unilateral thoracotomy, were allocated to three equal groups of 20 patients. Each patient received thoracic epidural analgesia using bupivacaine alone (Group A) or with magnesium (Group B) or clonidine (Group C) at the end of surgery during skin closure. Postoperatively, pain was measured using a visual analog scale (VAS). Rescue analgesia (50 mg tramadol intravenous) was given at a VAS score of ≥4. Duration of analgesia and total dose of rescue analgesic during 24 h was calculated. Postoperative sedation and other side effects if any were recorded. RESULTS: All the groups were homogeneous with respect to their demographics. The 24 h cumulative mean VAS score in Groups A, B, and C was 3.12 ± 0.97, 2.86 ± 0.43, and 1.83 ± 0.59, respectively. The duration of analgesia was prolonged in Group C (165 ± 49.15 min), followed by Group B (138 ± 24.6 min), and Group A (118.5 ± 52.8 min). The duration of analgesia was significantly prolonged in the clonidine group as compared to the control group (P = 0.001). The number of rescue analgesia doses were more in Group A (3.3 ± 1.65) followed by Group B (2.35 ± 0.98) and Group C (1.75 ± 0.71). The sedation scores were significantly higher in Group C. However, shivering was seen in Group A (40%) and Group C (20%) and absent in Group B (P = 0.003). CONCLUSION: Thoracic epidural analgesia using bupivacaine with clonidine is an efficient therapeutic modality for postthoracotomy pain. Magnesium as an adjuvant provided quality postoperative analgesia decreasing the need for postoperative rescue analgesia and incidence of postoperative shivering without causing sedation.

A prospective, randomized, double blind study to compare the effects of equiosmolar solutions of 3% hypertonic saline and 20% mannitol on reduction of brain-bulk during elective craniotomy for supratentorial brain tumor resection.

AIMS: The aim of the study was to compare the effect of mannitol (M) and hypertonic saline (HTS) on brain relaxation and electrolyte balance. SETTINGS AND DESIGN: Prospective, randomized, double-blind study. SUBJECTS AND METHODS: A total of 114 patients with American Society of Anesthesiologists status II and III, scheduled to undergo craniotomy for supratentorial brain tumor resection were enrolled. Patients received 5 ml/kg 20% mannitol (n = 56) or 3% HTS (n = 58) at the start of scalp incision. Hemodynamics, fluid balance and electrolytes, were measured at 0, 15, 30, and 60 min and 6 h after infusion. Intensive Care Unit (ICU) stay between the two groups was also recorded. The surgeon assessed brain relaxation on a four-point scale (1 = Relaxed, 2 = Satisfactory, 3 = Firm, 4 = Bulging). Appropriate statistical tests were used for comparison; P < 0.05 was considered significant. RESULTS: Brain relaxation conditions in the HTS group (relaxed/satisfactory/firm/bulging, n = 28/20/5/3) were better than those observed in the M group (relaxed/satisfactory/firm/bulging, n = 17/21/11/9). The levels of serum sodium were higher in the HTS group (P < 0.001). The average urine output was higher in the M group (5.50 ± 0.75 L) than in the HTS group (4.38 ± 0.72 L) (P < 0.005). There was no significant difference in fluid input, ICU stay, and hospital days between the two groups. CONCLUSION: We concluded that HTS provided better brain relaxation than mannitol during elective supratentorial brain tumor surgery, without affecting ICU and hospital stay.

Molecular weight of barley ß-glucan influences energy expenditure, gastric emptying and glycaemic response in human subjects.

Barley ß-glucan (BG) has been shown to reduce glycaemic response (GR) in some studies. It is hypothesised that this reduction may be a function of its physical properties that delay gastric emptying (GE). The effect of these changes in GR and GE on diet-induced thermogenesis (DIT) is not known. The aim of the present study was to assess the effect of BG of different molecular weights and purities on GR, GE and DIT in healthy subjects. This was a randomised, single-blind, repeated-measures design where fifteen healthy subjects were tested on three occasions following an overnight fast. Following the baseline measurements, the volunteers were fed a soup containing high-molecular-weight BG (HBG), a soup containing low-molecular-weight BG (LBG) or a control soup with no BG (CHO). Following the consumption of the breakfast, GR was measured using finger-prick blood samples, GE was determined using the 13C-octanoic acid breath test and DIT was measured using indirect calorimetry. There was a difference in GR AUC between the soups after 60 min but not after 120 min. The CHO and LBG meals had a greater GR than the HBG meal. There were differences in all GE time points, with the HBG meal having the slowest GE time. There was a correlation between the GR and the initial GE times. There were differences in total DIT between the three test meals with the HBG meal having the lowest DIT. The present study indicates that HBG has the ability to delay GE due to increased viscosity, resulting in a decreased GR and DIT.

Reducing sperm concentration is critical to limiting the oxidative stress challenge in liquid bull semen.

Because of the short breeding season, the use of liquid bull semen is a viable option in seasonal grass-based dairy systems such as Ireland. Currently in Ireland, liquid bull semen contains approximately 5 million sperm per insemination dose and is used within 2.5d of collection. The hypothesis of this study was that reducing the sperm number per insemination dose would enable bull sperm to be stored for longer. Semen was collected at a commercial AI center and diluted to 1 (T1), 2 (T2), 3 (T3), 4 (T4), and 5 (T5) million sperm per 0.25-mL dose in caprogen diluent. On d 0.25 (6 h postcollection), 1, 2, 3, 4, and 5 postcollection, viability, oxidative stress, and mitochondrial activity were assessed using flow cytometry and the fluorescent probes propidium iodide, CM-H2DCFDA, and rhodamine 123, respectively. On the same days, glucose consumption, total antioxidant capacity, and progressive linear motility were assessed. We observed an effect of day and treatment on sperm cell viability, with the highest percentage live found in T 0005 and the lowest in T 0025 on all days. Oxidative stress in live sperm increased with duration of storage and was affected by treatment, being highest in T 0025 and lowest in T 0005 on all days (d 5: 56.4±2.76% and 28.8±1.22%, respectively; mean ± SEM). Both the total antioxidant capacity and percentage of live sperm positive for rhodamine 123 were unaffected by treatment. The concentration of glucose in caprogen declined with time and was lowest in T 0025 and highest in T 0005 on d 5. In conclusion, higher concentrations of sperm have detrimental effects on sperm cell viability and increase oxidative stress but have no effect on the mitochondrial activity of sperm.

Soups increase satiety through delayed gastric emptying yet increased glycaemic response.

BACKGROUND/OBJECTIVES: Previous studies have demonstrated the satiating properties of soups compared with solids; however, the mechanisms controlling soup-induced satiety are unknown. This study aimed to understand the physiological mechanisms causing soup to be more satiating. SUBJECTS/METHODS: A total of 12 volunteers were tested on three occasions after a solid meal, chunky soup or smooth soup test meal for gastric emptying (GE) using the sodium [1-¹³C] acetate breath test, satiety using visual analog scales (VAS) and glycaemic response (GR) using finger prick blood samples. RESULTS: There was a significant difference in GE half-time (P=0.022) and GE ascension time (P=0.018), with the longest GE times for the smooth soup and the shortest for the solid meal. The GR area under the curve was significantly different between meals (P=0.040). The smooth soup had the greatest GR (87.0 ± 49.5 mmol/l/min), followed by the chunky soup (65.4 ± 48.0 mmol/l/min), with the solid meal having the lowest GR (61.6 ± 36.8 mmol/l/min). Volunteers were fuller after the smooth soup compared with solid meal (P=0.034). CONCLUSIONS: The smooth soup induced greater fullness compared with the solid meal because of a combination of delayed GE leading to feelings of gastric distension and rapid accessibility of nutrients causing a greater glycaemic response.

Rapamycin inhibition of baculovirus recombinant (BVr) ribosomal protein S6 kinase (S6K1) is mediated by an event other than phosphorylation.

BACKGROUND: Ribosomal protein S6 kinase 1(S6K1) is an evolutionary conserved kinase that is activated in response to growth factors and viral stimuli to influence cellular growth and proliferation. This downstream effector of target of rapamycin (TOR) signaling cascade is known to be directly activated by TOR- kinase mediated hydrophobic motif (HM) phosphorylation at Threonine 412 (T412). Selective loss of this phosphorylation by inactivation of TOR kinase or activation/recruitment of a phosphatase has accordingly been implicated in mediating inhibition by rapamycin. FINDINGS: We present evidence that baculovirus driven expression of S6K1 in insect cells (Sf9) fails to activate the enzyme and instead renders it modestly active representing 4-6 folds less activity than its fully active mammalian counterpart. Contrary to the contention that viral infection activates TOR signaling pathway, we report that BVr enzyme fails to exhibit putative TOR dependent phosphorylation at the HM and the resultant phosphorylation at the activation loop (AL) of the enzyme, correlating with the level of activity observed. Surprisingly, the BVr enzyme continued to exhibit sensitivity to rapamycin that remained unaffected by mutations compromised for TOR phosphorylation (T412A) or deletions compromised for TOR binding (ΔNH 2-46/ΔCT104). CONCLUSIONS: These data together with the ability of the BVr enzyme to resist inactivation by phosphatases indicate that inhibition by rapamycin is not mediated by any phosphorylation event in general and TOR dependent phosphorylation in particular.

Does domperidone, a D2-antagonist alter gastric emptying rates and appetite sensations in healthy adults with high-fat meal? A block-randomised, single-blind placebo-controlled study.

BACKGROUND: Accelerated gastric emptying (GE) may lead to reduced satiation, increased food intake and is associated with obesity and type 2 diabetes. Domperidone is a dopamine 2 (D(2)) receptor antagonist with claims of gastrointestinal tract pro-kinetic activity. In humans, domperidone is used as an anti-emetic and treatment for gastrointestinal bloating and discomfort. AIM: To determine the effect of acute domperidone administration on GE rate and appetite sensations in healthy adults. METHODS: A single-blind block randomised placebo-controlled crossover study assessed 13 healthy adults. Subjects ingested 10 mg domperidone or placebo 30 min before a high-fat (HF) test meal. GE rate was determined using the (13)CO(2) octanoic acid breath test. Breath samples and subjective appetite ratings were collected in the fasted and during the 360 min postprandial period. RESULTS: Gastric emptying half-time was similar following placebo (254 ± 54 min) and 10 mg domperidone (236 ± 65 min). Domperidone did not change appetite sensations during the 360 min postprandial period (P > 0.05). CONCLUSIONS: In healthy adults, acute administration of 10 mg domperidone did not change GE or appetite sensations following a HF test meal.

Gastrointestinal transit, post-prandial lipaemia and satiety following 3 days high-fat diet in men.

BACKGROUND/OBJECTIVES: High-fat (HF) diets of 2 weeks have been shown to accelerate gastric emptying (GE). To date, no studies have shown any alteration in GE following shorter HF diets. The aim of this study was to assess if an HF, high-energy diet of 3 days can adapt gastrointestinal (GI) transit, blood lipids and satiety. SUBJECTS/METHODS: Eleven male volunteers participated in a study consisting of three, 3-day interventions each separated by a test day. During the first intervention, volunteers recorded their diet. In the second and third interventions, volunteers repeated their food diary plus either a low-fat yogurt or HF yogurt supplement in randomized order. Test days involved measurement of GE using the (13)C octanoic-acid breath-test, mouth-to-caecum transit time (MCTT) using the inulin H(2) breath test and satiety using visual analogue scales. Blood samples for measurement of lipaemia were taken using a venous cannula. RESULTS: MCTT was different between the three test days (P=0.038), with the shortest MCTT following the HF intervention. GE was shortest following the HF intervention. There were no differences in satiety between the interventions. The HF intervention reduced triglycerides, total cholesterol and low-density lipoprotein cholesterol, and increased high-density lipoprotein cholesterol. CONCLUSION: This study shows that changes in GI transit owing to an HF diet can occur in a time period as short as 3 days.

Progressive resistance training temporarily alters hamstring torque-angle relationship.

To examine the effects of eccentric and concentric progressive resistance training on muscle torque-angle relationship, 30 young adults were randomly allocated into three groups of 10, control (CTL), eccentric training (ECC) and concentric training (CON). The ECC and CON groups performed seven sessions over 3 weeks of progressive resistance training of the right hamstrings muscle, using a standard barbell and a leg curl machine. Torque-angle relationship was measured before and 4, 11 and 18 days after the end of training. Voluntary isometric torque was recorded at seven test angles, with the subject prone (20-80 degrees; 0 degrees is full extension). In the CON group, the angle of peak isometric torque increased from 46.0 +/- 5.2 degrees pre-training to 53.0 +/- 14.9 degrees on day 4 following training (P<0.05). In the ECC group, peak torque was increased over baseline on days 4 and 11 post-training, particularly at extended knee angles (P<0.05). The angle at which peak torque occurred was decreased on day 4 (50.0 +/- 8.2 degrees pre-training, 29.0 +/- 7.4 degrees on day 4) and on day 11 (both P<0.01), but was similar to baseline 18 days after training. ECC therefore induced a temporary change in torque-angle relationship.

Effects of dietary supplementation with vitamins C and E on muscle function during and after eccentric contractions in humans.

Reactive oxygen species may contribute to exercise-induced skeletal muscle damage, and antioxidants may protect against such damage. This study examined the effectiveness of prophylactic supplementation with vitamins C and E on symptoms of muscle damage in a single blind, two-group study design. Twelve male volunteers were randomly assigned to either treatment or control groups. The treatment group received 500 mg of vitamin C and 1,200 IU of alpha-tocopherol daily and the control group received glucose placebo for 37 days. After 30 days of treatment, volunteers performed 300 maximal eccentric contractions of the knee extensor muscles of one leg. Maximal voluntary isometric contraction force and electrically evoked force at a frequency of 20 Hz and 50 Hz were recorded before and after exercise, and on days 1, 2 and 7 after exercise. Muscle soreness questionnaires were completed and muscle girth recorded at the same time points. Eccentric contractile torque and work during the bout declined significantly in both groups ( P<0.001), but this decline was smaller in the vitamin-supplemented group ( P<0.05). Maximal voluntary isometric contraction force and 20:50 Hz force ratio declined significantly after exercise in both groups ( P<0.01), but the decline was smaller in the treatment group on days 1 and 2 post-exercise ( P<0.05). Both groups experienced similar significant muscle soreness and swelling after exercise. These data suggest that prior supplementation with dietary antioxidants ameliorates muscle functional decrements subsequent to eccentric muscle contraction.