Sustainable food packaging: Harnessing biowaste of Terminalia catappa L. for chitosan-based biodegradable active films for shrimp storage

Shrimp, a globally consumed perishable food, faces rapid deterioration during storage and marketing, causing nutritional and economic losses. With a rising environmental consciousness regarding conventional plastic packaging, consumers seek sustainable options. Utilizing natural waste resources for packaging films strengthens the food industry. In this context, we aim to create chitosan-based active films by incorporating Terminalia catappa L. leaves extract (TCE) to enhance barrier properties and extend shrimp shelf life under refrigeration. Incorporation of TCE improves mechanical, microstructural, UV, and moisture barrier properties of the chitosan film due to cross-linking interactions, resulting in robust, foldable packaging film. Active TCE film exhibits high antioxidant property due to polyphenols. These films also exhibited low wettability and showed hydrophobicity than neat CH films which is essential for meat packaging. These biodegradable films offer an eco-friendly end-of-life option when buried in soil. TCE-loaded films effectively control spoilage organisms, prevent biochemical spoilage, and maintain shrimp freshness compared to neat CH films during refrigerated condition. The active TCE film retains sensory attributes better than neat chitosan, aligning with consumer preference. The developed edible and active film from waste sources might offer sustainable, alternative packaging material with a lower carbon footprint than petroleum-based sources.

Exploring the Efficacy of Pellitorine as an Antiparasitic Agent Against Argulus: Impacts on Antioxidant Levels and Immune Responses in Goldfish (Carassius auratus)

INTRODUCTION

Argulus spp. infestation is a significant challenge for aquaculture, currently, there are no approved medications available to efficiently manage this parasite. Consequently, mechanical removal of parasites using forceps and natural substances like herbs are being explored as alternative treatment methods. Pellitorine (PLE) is a naturally occurring compound found in several plant species. It is classified as an alkaloid and belongs to the class of compounds known as amides.

MATERIALS AND METHODS

This study aimed to evaluate the effectiveness of PLE in preventing Argulus spp. infestations in goldfish (Carassius auratus) and to determine the optimal dosage of PLE for the detachment of Argulus spp.

RESULTS

The findings of this study revealed that PLE enhanced the immune response of goldfish by promoting superoxide dismutase (SOD) and catalase (CAT) in Argulus-infected goldfish. Additionally, PLE induces reactive oxygen species (ROS) generation and cellular damage in the Argulus. PLE at a dosage of 5 mg/mL was able to detach 80% of the argulus from goldfish within 12 h. Therapeutic index was found to be 5.99, suggesting that PLE is the safest drug.

CONCLUSIONS

Therefore, our findings suggest that PLE can be a suitable and effective treatment option for preventing Argulus infestations in goldfish. The results of this study can guide the use of PLE at an optimal dosage to control Argulus infestation in goldfish.

Application of Bacillus Coagulans as Paraprobiotic Against Acute Hepatopancreatic Necrosis Disease in Shrimp

Paraprobiotics, known as non-viable or ghost probiotics, have attracted attention for their benefits over live microbial cells. This study was designed to investigate the paraprobiotic effects of heat-killed Bacillus coagulans on the white leg shrimp Litopenaeus vannamei. The paraprobiotic formulation was prepared in three different concentrations including B. coagulans 1 (107 cells g-1 diet), B. coagulans 2 (108 cells g-1 diet), and B. coagulans 3 (109 cells g-1 diet) through heat inactivation method. Preliminary toxicity assessments revealed that post-larvae shrimps (mean weight ± SE: 0.025 ± 0.007 g) treated with B. coagulans 1, 2 and 3 paraprobiotic formulations exhibited no mortality, confirming the non-toxic nature of the formulated diet. In a 90-day feeding trial involving juvenile shrimps (mean weight ± SE: 0.64 ± 0.05 g), growth parameters and feed conversion ratios improved in all experimental groups. Subsequently, these shrimps were challenged with Vibrio parahaemolyticus, revealing that paraprobiotic-fed shrimps exhibited significant survival rate improvements. Oxidative stress-related enzyme activities, such as superoxide dismutase and catalase, increased in paraprobiotic-fed shrimps post-Vibrio challenge, while the challenged control group showed decreased activity (p < 0.001). Nitric oxide levels are also increased in paraprobiotic-treated shrimp, with B. coagulans 3 showing a significant rise in nitric oxide activity (p < 0.001). This study further demonstrated the positive impact of paraprobiotic treatment on digestive enzymes, immune-related parameters (e.g., total hemocyte count, prophenoloxidase, and respiratory burst activity), and overall disease resistance. These findings suggest that B. coagulans paraprobiotics have the potential to enhance antioxidant, antibacterial, and immune-related responses in L. vannamei, making them a valuable addition to shrimp aquaculture.

A Dual Therapy of Nanostructured Lipid Carrier Loaded with Teriflunomide-A Dihydro-Orotate Dehydrogenase Inhibitor and an miR-155-Antagomir in Cuprizone-Induced C57BL/6J Mouse

The effective treatment of central nervous system (CNS) disorders such as multiple sclerosis (MS) has been challenging due to the limited ability of therapeutic agents to cross the blood-brain barrier (BBB). In this study, we investigated the potential of nanocarrier systems to deliver miR-155-antagomir-teriflunomide (TEF) dual therapy to the brain via intranasal (IN) administration to manage MS-associated neurodegeneration and demyelination. Our results showed that the combinatorial therapy of miR-155-antagomir and TEF loaded in nanostructured lipid carriers (NLCs) significantly increased brain concentration and improved targeting potential. The novelty of this study lies in the use of a combinatorial therapy approach of miR-155-antagomir and TEF loaded in NLCs. This is a significant finding, as the effective delivery of therapeutic molecules to the CNS has been a challenge in treating neurodegenerative disorders. Additionally, this study sheds light on the potential use of RNA-targeting therapies in personalized medicine, which could revolutionize the way CNS disorders are managed. Furthermore, our findings suggest that nanocarrier-loaded therapeutic agents have great potential for safe and economical delivery in treating CNS disorders. Our study provides novel insights into the effective delivery of therapeutic molecules via the IN route for managing neurodegenerative disorders. In particular, our results demonstrate the potential of delivering miRNA and TEF via the intranasal route using the NLC system. We also demonstrate that the long-term use of RNA-targeting therapies could be a promising tool in personalized medicine. Importantly, using a cuprizone-induced animal model, our study also investigated the effects of TEF-miR155-antagomir-loaded NLCs on demyelination and axonal damage. Following six weeks of treatment, the TEF-miR155-antagomir-loaded NLCs potentially lowered the demyelination and enhanced the bioavailability of the loaded therapeutic molecules. Our study is a paradigm shift in delivering miRNAs and TEF via the intranasal route and highlights the potential of this approach for managing neurodegenerative disorders. In conclusion, our study provides critical insights into the effective delivery of therapeutic molecules via the IN route for managing CNS disorders, and especially MS. Our findings have significant implications for the future development of nanocarrier-based therapies and personalized medicine. Our results provide a strong foundation for further studies and the potential to develop safe and economic therapeutics for CNS disorders.

Impact of Exercise and Cognitive Stimulation Therapy on Physical Function, Cognition and Muscle Mass in Pre-Frail Older Adults in the Primary Care Setting: A Cluster Randomized Controlled Trial

OBJECTIVES

Multicomponent exercise program have shown to improve function and cognition in older adults but studies on pre-frail older adults in the primary care setting are limited. This study aimed i) to evaluate impact of 6 months exercise (Ex) versus complementary effect of 3 months of cognitive stimulation therapy (CST) to 6 months of Ex (Ex+CST) on physical function, muscle mass and cognition versus control group at 3, 6 and 12 months ii) inflammatory biomarkers such as Interleukin-6 (IL-6) and Tumor Necrosis Factor Alpha (TNF-α).

DESIGN

Cluster randomised control trial.

SETTING AND INTERVENTION

Pre-frail older adults ≥ 65 years attending primary care clinic. Two intervention groups i) Ex 6 months ii) CST 3 months with Ex 6 months.

MEASUREMENTS

At 0, 3, 6 and 12 months, questionnaires (on demographics, physical function, cognition, and depression) were administered and physical function assessment (gait speed, short physical performance battery (SPPB) test, handgrip strength, five times sit-to-stand (5x-STS)) was conducted. Muscle mass and its surrogates such as phase angle and body cell mass were measured using bioelectrical impedance analysis machine. Inflammatory biomarkers were measured at 0 and 3 months.

RESULTS

Data from 190 participants was analysed at 3 months (111 control, 37 Ex and 41 Ex+CST). At 3 months, significant improvement in cognition was seen only in the Ex+CST group whereas improvements in depression, gait speed, SPPB and 5x-STS were seen in both the Ex and Ex+CST groups. At 6 months, the Ex+CST group improved in cognition and depression whereas improvement in frailty and muscle mass indices were seen in both the interventions groups. At 12 months, both the interventions groups had better perceived health, gait speed and less decline in muscle mass compared with control groups. Both the Ex and Ex+CST had significant association with TNF-α at 3 months (β -2.71 (95% CI -4.80 - -0.62); p = 0.012 and β -1.74 (95% CI -3.43 - -0.06); p = 0.043 respectively).

CONCLUSION

Combined Ex+CST had significant improvement in cognition whereas the intervention groups improved in depression, physical function, muscle mass, frailty, perceived health and TNF-α levels. With growing evidence of the benefits of multicomponent interventions at primary care level, incorporating it into mainstream care with action plans on long-term sustainability and scalability should be a priority for every country.

Comparison of viscosities of human breast milk versus infant milk formulae with and without addition of sweetening agents

CONTEXT

Early childhood caries is a major health problem affecting children worldwide. Although incorrect feeding practices hold a prime position in the etiology, there are gaps in the literature pertaining to the physical properties of milk.

AIM

To assess the viscosity of human breast milk (HBM) versus infant milk formulae, with and without the addition of sweetening agents.

MATERIALS AND METHODS

All commercially available infant milk formulae (60 samples) and breast milk from 30 donor mothers were assessed for viscosity using Brookfield DV2T viscometer. The study period was from April 2019 to August 2019. Viscosity of infant milk formulae sweetened with sugar, honey, and brown sugar was further investigated and compared with that of HBM.

STATISTICAL ANALYSIS

Inter-group and intra-group mean viscosity was compared using independent t-test and repeated-measures ANOVA.

RESULTS

Viscosity of HBM ranged from 18.36 centipoise (cP) to 91.30 cP, the mean viscosity being 45.7 cP. Viscosity values varied for each formula group, the least being as low as 5.1 cP and the highest being 89.3 cP. The mean viscosities of each group were in the range of 33 to 49 cP.

CONCLUSIONS

HBM was found to have a tendency toward higher viscosity than most of the infant milk formulae. Also, varied viscosity values were obtained when commonly used sweetening agents were added to infant milk formulae. Greater viscosity of HBM might increase its adherence to enamel surface leading to prolonged demineralization and potentially altering the caries risk, needs to be investigated further.

Integrative study of gene expression datasets in retinal samples of Diabetic Retinopathy

Diabetic Retinopathy is prevalent among patients with uncontrolled hyperglycemia resulting in vision loss. Despite numerous challenges to create a link among these conditions, the characterization of pathological neovascularization causing retinal damage due to the prognosis of early non-proliferative diabetic retinopathy to late proliferative diabetic retinopathy needs deep understanding. In this study, meta-analysis-based integration of gene expression datasets for the fibrovascular membrane of PDR and neural retina of NPDR were compared, to investigate the differentially expressed genes involved in retinal angiogenesis. Human samples with gene expression profiling of the same experiment type and platform with sufficient information for analysis were included in the study. The studies from cell lines and non-human studies, human samples that include serum, cornea, lens, and/or other ocular tissues or fluids, and studies that lack basic information for analysis were excluded. The microarray datasets available in the Gene Expression Omnibus database of the early and late stages in DR were screened to find common gene expression profiles. Using the INMEX bioinformatics tool, significantly upregulated and downregulated genes in the neural retina of Non-Proliferative Diabetic Retinopathy and fibrovascular membrane of Proliferative Diabetic Retinopathy were compared and studied by the combine effect size method. Using the STRING database PPI network, 50 upregulated and 50 downregulated genes were used to find the key candidate genes involved in retinal disease/degeneration in eye/retinal tissues. In the extensive gene expression meta-analysis performed using INMEX bioinformatics tool, overall, 7935 differentially expressed genes were identified and the respective heatmap was created by using the visualization tools of INVEX. STRING database PPI network identified Retinol Binding Protein 3, Neural Retina Leucine Zipper, S-Antigen Visual Arrestin, Peripherin 2, and Aryl Hydrocarbon Receptor Interacting Protein Like-1 to be the most highly ranked hub genes. The newly discovered potential genes related to retinal angiogenesis causing FVM formation in DR may provide insight into the cellular pathogenesis of NPDR to PDR.

Microvascular cells: A special focus on heterogeneity of pericytes in diabetes associated complications

Pericytes (PC) are microvascular mural cells that make specific cell-to-cell contacts with the endothelial cells (EC). These cells are obligatory constituents of the microvessels including the retinal vasculature and they serve as regulators of vascular development, stabilization, maturation and remodeling. During early stages of diabetic retinopathy (DR), apoptotic loss of PC surrounding the retinal vasculature occurs. This may lead to reduced vessel stability, the onset of EC apoptosis, and subsequent retinal ischemia leading to angiogenesis and eventually, severe vision loss due to late proliferative diabetic retinopathy (PDR). Similarly, diabetic nephropathy (DN) is a chronic kidney disease due to hyperglycemia that particularly affects renal PC. Chronic high blood glucose level causes migration of peritubular PC away from the capillary into the interstitial space, which destabilizes the micro vessels, resulting in microvascular rarefaction. In both diabetes associated complications, the identification of specific biomarkers is necessary to stabilize the PC at an early stage. This review largely covers the importance of PC towards the pathogenesis of diabetes associated complications, and their heterogeneity in healthy and angiogenic vasculature.

Association of Pain and Impact of Dual-Task Exercise on Function, Cognition and Quality of Life

PURPOSE

This study aimed to assess the factors associated with pain and evaluate the impact of dual-task exercise on pain improvement, quality of life (QOL), cognition and function in older adults.

PATIENTS AND METHODS

This study is a secondary data analysis of the HAPPY (Healthy Ageing Promotion Program for You) study. At risk older adults ≥ 60 years old were enrolled in a community dual-task exercise program. Assessments for frailty, sarcopenia, falls, quality of life (QOL) and perceived health, depression, cognition and physical function were performed at baseline and 3 months. Pain intensity was derived from EQ-5D and stratified into no pain, slight pain and moderate to extreme pain.

RESULTS

Out of 296 participants, 37.2% had slight pain and 11.1% had moderate to severe pain. Both slight and moderate to extreme pain compared with no pain group were significantly associated with lower perceived health (68.2,63.6 vs 76.0) and QOL index (0.70,0.59 vs 0.93); moderate to extreme pain was also significantly associated with depression, low mental vitality, frailty, sarcopenia and poorer physical performance. After 3 months of dual-task exercise, pain improved in 70.8% of the moderate to extreme pain group and 50.8% of slight pain group. Significant improvement in perceived health, QOL, physical function and cognition were also observed.

CONCLUSION

Proactive efforts are required to screen for pain and manage frailty, sarcopenia and depression. Dual-task exercise proved safe and possibly effective in reducing pain and improving QOL, physical and cognitive function in older adults. Prospective randomized studies are needed to validate the effectiveness of dual-task vs single-task exercise, including impact of reversal of frailty and sarcopenia in pain management.

Pharmacokinetic Investigation to Study the In Vivo Bioavailability of Thiolated Chitosan Based Repaglinide Buccal Tablets

Background: Repaglinide (REP) is an antihyperglycemic drug having low bioavailability due to its extensive first-pass metabolism. The present study aimed to develop and pharmacokinetic investigte the thiolated chitosan (TC) based buccal tablets of REP for improved bioavailability. Methods: TC was prepared by conjugation of L-cysteine with chitosan. The amount of free thiol groups present in TC was determined by UV-spectrophotometry using Ellman’s reagent. TC based REP buccal tablets were prepared by two layers co-compression method and characterized for in vitro and ex vivo parameters. The in vivo performance of prepared REP buccal tablets was assessed by the pharmacokinetic study in New Zealand white rabbits. Results: The prepared TC resulted in 87%w/w yield with 52.3±3.2 μM free thiol functional groups per 10 mg of TC. The prepared formulations have good flow nature and compressibility, acceptable thickness (2.02 to 2.1 mm), weight (60.11 to 61.06 mg), surface pH (6.59 to 6.81) and drug content (98.92 to 101.08 %w/w). The presence of TC significantly improved the mucoadhesion strength, sustained the in vitro release and enhanced the ex vivo permeation of REP buccal tablets. The shelf life of REP buccal tablets was found to be 15.07 months in accelerated storage conditions. The prepared REP buccal tablets (V5) have area under the curve (712.22±15.91 ng/mL/h) and mean residence time (4.66±0.25 h) was 1.89 and 1.83 folds higher than oral bolus respectively. Conclusion: TC based REP buccal tablets are capable of controlled transbuccal release of REP for a prolonged time and have better bioavailability than oral bolus.

Delivery of silver sulfadiazine and adipose derived stem cells using fibrin hydrogel improves infected burn wound regeneration

Infection control is necessary for improved burn wound regeneration. In this study contact burn wounds were induced on the dorsum of the rats and were infected with Pseudomonas aeruginosa (107cfu/ml of saline) and left overnight (12-14 hours) to establish the infection. After 12 hours, the wounds were treated with PEGylated fibrin hydrogel containing 50 mgs of silver sulfadiazine (SSD) loaded chitosan microsphere (SSD-CSM-FPEG). On day 9, SSD-CSM-FPEG treated burn wounds further received adipose derived stem cell (5×104 ASCs cells/ml) embedded in PEGylated fibrin hydrogel. Wounds were assessed for the healing outcomes such as neovascularization, granulation tissue formation, wound closure and collagen maturation. Analysis of bacterial load in the burn wound biopsies, demonstrated that SSD-CSM-FPEG significantly reduced bacterial infection, while overt infection was still observed in the untreated groups on day 14. Sequential treatment of infected wounds with SSD-CSM-FPEG followed by ASC-FPEGs (SSD-CSM-ASC-FPEG) significantly reduced bacterial colonization (9 log reduction) and pro-inflammatory cytokine (TNF-α) expression. A significant increase in neovascularization markers; NG2 and vWF was also observed. Histological analysis indicated the wounds treated with SSD-CSM-ASC-FPEG increased amount of dermal collagen matrix deposition, a thicker granulation tissue on day 21 and more mature collagen on day 28. This work demonstrates that the sequential treatment of infected burn wounds with SSD-CSM-FPEG followed by ASC-FPEG reduces bacterial infection as well as promotes neo-vascularization with improved matrix remodeling.

Type I collagen peptides and nitric oxide releasing electrospun silk fibroin scaffold: A multifunctional approach for the treatment of ischemic chronic wounds

Biomimetic nanofibrous scaffolds targeting multiple dysfunctional processes provide a multi-pronged strategy to restore functions and regenerate the damaged tissue. This study investigates a strategy of combining a regenerative component, Type I collagen Peptide (CP), along with a nitric oxide donor, S-Nitrosoglutathione (GSNO), in the form of nanofibrous scaffold to address the non-healing diabetic ulcer. Silk Fibroin-Polyvinyl alcohol (SF-PVA) nanofibrous scaffold is used as a carrier for delivering functional moieties. The developed nanofibrous electrospun mats (SF-PVA, CP-SF-PVA, and CP-GSNO-SF-PVA) showed continuous, bead-less and randomly oriented fibers with highly porous morphology. The in vitro biocompatibility was assessed by MTT assay, DAPI-Rhodamine 123 and FITC-Phalloidin imaging studies. CP-GSNO-SF-PVA nanofibrous scaffold showed a high degree of cell attachment, spreading of F-actin with viable cell morphology and appreciable inter-cellular connection. Thus the study showed that the proliferation of fibroblast cells are mainly facilitated by the presence of collagen peptide in the nanofibrous matrix. Griess assay demonstrated immediate release of NO for a day from the developed multifunctional scaffold. These results demonstrate the in vitro efficacy of CP-GSNO and indicate the opportunity of CP-GSNO-SF-PVA nanofibrous scaffold for the treatment of ischemic non-healing ulcers.

Amelioration of lesions associated with 24-hour suboptimal platelet storage at 16 °C by a p38MAPK inhibitor, VX-702

BACKGROUND AND OBJECTIVES

Previous studies with p38MAPK inhibitors at room temperature demonstrated that they improve a large number of platelet storage parameters, but cannot substantially inhibit p38MAPK activation nor protect against widespread decrements in platelet quality parameters during 4 °C storage. In this study, platelet quality parameters and inhibition of p38MAPK by VX-702 were studied after incubation of platelets at 16 °C without agitation, suboptimal storage conditions which produce moderate platelet decrements.

MATERIALS AND METHODS

Trima apheresis units were collected and aliquoted into three 60-ml CLX storage bags: (i) a control aliquot which was held at 20-24 °C with constant agitation; (ii) a test aliquot which was held at 20-24 °C with agitation until Day 2, when it was reincubated at 16 ± 1 °C for 24 ± 0·5 h without agitation and then returned 20-24 °C with agitation; (iii) a test aliquot containing 1 μm VX-702 stored in an identical fashion as aliquot 2. Aliquots were tested for an array of platelet storage parameters and p38MAPK activation on Days 1, 4 and 7.

RESULTS

Many platelet storage parameters and p38MAPK activation were adversely affected by 24-h incubation at 16 °C without agitation. With the exception of ESC, addition of VX-702 prevented p38MAPK activation and the decrements in most observed parameters.

CONCLUSION

Unlike 4 °C storage, VX-702 prevents activation of p38MAPK and decrements in many platelet storage parameters after exposure to 16 °C without agitation for 24 h.

Hypertrophic Cardiomyopathy: A Real Risk Factor for Stroke

Hypertrophic cardiomyopathy is a common and complex heterogeneous cardiovascular entity. Its relationship to ischaemic stroke and atrial fibrillation is under-recognized and consequently, many patients who should be on oral anticoagulation for stroke prevention go untreated.

A PEGylated fibrin-based wound dressing with antimicrobial and angiogenic activity

Wounds sustained under battlefield conditions are considered to be contaminated and their initial treatment should focus on decreasing this contamination and thus reducing the possibility of infection. The early and aggressive administration of antimicrobial treatment starting with intervention on the battlefield has resulted in improved patient outcomes and is considered the standard of care. Chitosan microspheres (CSM) loaded with silver sulfadiazine (SSD) were developed via a novel water-in-oil emulsion technique to address this problem. The SSD-loaded spheres were porous with needle-like structures (attributed to SSD) that were evenly distributed over the spheres. The average particle size of the SSD-CSM was 125-180 μm with 76.50 ± 2.8% drug entrapment. As a potential new wound dressing with angiogenic activity SSD-CSM particles were impregnated in polyethylene glycol (PEGylated) fibrin gels. In vitro drug release studies showed that a burst release of 27.02% in 6h was achieved, with controlled release for 72 h, with an equilibrium concentration of 27.7% (70 μg). SSD-CSM-PEGylated fibrin gels were able to exhibit microbicidal activity at 125 and 100 μg ml(-1) against Staphylococcus aureus and Pseudomonas aeruginosa, respectively. The in vitro vasculogenic activity of this composite dressing was shown by seeding adipose-derived stem cells (ASC) in SSD-CSM-PEGylated fibrin gels. The ASC spontaneously formed microvascular tube-like structures without the addition of any exogenous factors. This provides a method for the extended release of an antimicrobial drug in a matrix that may provide an excellent cellular environment for revascularization of infected wounds.

High-temperature mass spectrometric study of the vaporization processes of V2O3 and vanadium-containing slags

A Knudsen effusion mass spectrometric method was used to study the vaporization processes and thermodynamic properties of pure V(2)O(3) and 14 samples of vanadium-containing slags in the CaO-MgO-Al(2)O(3)-SiO(2) system in the temperature range 1875-2625 K. The system was calibrated using gold in the liquid state as the standard. Vaporization was carried out from double tungsten effusion cells. First it was shown that, in vapor over V(2)O(3) and the vanadium-containing slags in the temperature range 1875-2100 K, the following vapor species were present: VO(2), VO, O, WO(3) and WO(2), with the latter two species being formed as a result of interaction with the tungsten crucibles. The temperature dependencies of the partial pressures of these vapor species were obtained over V(2)O(3) and the slags. The ion current comparison method was used for the determination of the V(2)O(3) activities in slags as a function of temperature with solid V(2)O(3) as a reference state. The V(2)O(3) activity coefficients in the slags under investigation indicated positive deviations from ideality at 1900 K and a tendency to ideal behavior at 2100 K. It was shown that the V(2)O(3) activity as a function of the slag basicity decreased at 1900 K and 2000 K and was practically constant in the slag melts at 2100 K. The results are expected to be valuable in the optimization of slag composition in high-alloy steelmaking processes as well as for their environmental implications.

High-temperature mass spectrometric study of the vaporization processes in the system CaO-MgO-Al2O3-Cr2O3-FeO-SiO2

Knudsen effusion mass spectrometry was used to study vaporization processes and thermodynamic properties of twenty samples of chromium-containing slags in the CaO-MgO-Al2O3-Cr2O3-FeO-SiO2 system in the temperature range 1850-2750 K. Tungsten cells were used and Cr2O3 solid was used as a reference material. The system was calibrated using liquid gold. As FeO was the first emanating vapor species, monitoring of the chromium-containing species could be carried out only after the complete vaporization of FeO. This, however, was found to have very little impact on the concentration of the slags investigated. During the measurements, the ion current intensities of CrO+ and CrO2+ species in the mass spectra of the vapor over the CaO-MgO-Al2O3-Cr2O3-FeO-SiO2 samples were monitored and compared with those corresponding to solid Cr2O3. Data on the partial pressures of vapor species as well as the activities of Cr2O3 as a function of temperature were obtained. The results are expected to be valuable in the optimization of slag composition in high alloy steelmaking processes.

Non-contingent positive and negative reinforcement schedules of superstitious behaviors

The role of schedules of reinforcement on the development of superstitious conditioning was investigated in a college age population. Participants were randomly assigned to one of eight operant schedules and instructed to remove (escape), prevent and/or remove (avoidance and escape) or produce (positive) the appearance of a computer generated stimulus using a response pad. Results from the experiment indicate that concomitant (escape and avoidance) schedules of reinforcement are most effective in facilitating acquisition of superstitious behavior as measured by self-reports of participants.

Inter-specific hybridization between freshwater catfish Mystus cavasius (Ham & Buch) and M. seenghala (Sykes) by artificial fertilization

By employing the technique of induced ovulation for artificial fertilization, inter-specific hybrids between the threatened catfish species (Mystus cavasius x M. seenghala) were produced. Fertilization, hatching and survival were significantly different between control and hybrids. The hatching time of the hybrid was significantly lower than that of the control. The average performance viz., hatching time and viability of larvae of the control fish, was significantly better than that of the hybrids. In the hybrid cross, hatchlings were mostly deformed and abnormal and after yolk absorption ultimately succumbed.

Comparison of total nucleated cell measurements of UC blood samples using two hematology analyzers

BACKGROUND

The total nucleated cell (TNC) content of umbilical cord blood (UCB) units currently serves as the most important measure for determining suitability for transplantation. Hence it is important that TNC measurements are performed in an accurate manner. TNC content is evaluated routinely by hematology analyzers (HA) as WBC counts. The objective of the study was to compare TNC content utilizing two different HA, one utilizing an impedance channel and optical channel, and the other using only an optical channel.

METHODS

The HA utilized in this study used two different modes of operation for lysis, regular mode (RM) and extended lysis mode (ELM). Cell-Dyn 3200 (CD3.2) utilizes optical technology for WBC measurements, involving WBC optical count (WOC) and nuclear optical count (NOC), whereas the Cell-Dyn 3700 (CD3.7) utilizes both the impedance (WIC) and optical technology (WOC) for WBC measurements. TNC content was determined with 17 identical samples using CD3.2 in one laboratory and CD3.7 in the other laboratory. Cord blood samples processed to concentrate nucleated cells by either of the laboratories were sent by overnight courier and assays were performed on the same day by both laboratories.

RESULTS

For CD3.7, the WOC values were consistently lower than the WIC using the regular mode, but showed no significant differences (P>0.05). The WIC and WOC values were comparable on using the ELM and RM. For CD3.2, WOC values using RM and NOC values using ELM showed no significant differences (P>0.05), even though the WOC measurement was lower than the NOC values for most samples. The best comparison of TNC measurement between the two HA could be achieved by comparing CD3.7-WIC with CD3.2-NOC values. The results were equivalent (P>0.05) and 12 of 17 samples had equal to or less than 10% difference (mean 9.5%).

DISCUSSION

TNC measurements of UCB samples were essentially identical using the WIC channel of the Cell-Dyn 3700 and the NOC channel of the Cell-Dyn 3200.

Identification and properties of a novel intracellular (mitochondrial) ATP-sensitive potassium channel in brain

Protection of heart against ischemia-reperfusion injury by ischemic preconditioning and K(ATP) channel openers is known to involve the mitochondrial ATP-sensitive K(+) channel (mitoK(ATP)). Brain is also protected by ischemic preconditioning and K(ATP) channel openers, and it has been suggested that mitoK(ATP) may also play a key role in brain protection. However, it is not known whether mitoK(ATP) exists in brain mitochondria, and, if so, whether its properties are similar to or different from those of heart mitoK(ATP). We report partial purification and reconstitution of a new mitoK(ATP) from rat brain mitochondria. We measured K(+) flux in proteoliposomes and found that brain mitoK(ATP) is regulated by the same ligands as those that regulate mitoK(ATP) from heart and liver. We also examined the effects of opening and closing mitoK(ATP) on brain mitochondrial respiration, and we estimated the amount of mitoK(ATP) by means of green fluorescence probe BODIPY-FL-glyburide labeling of the sulfonylurea receptor of mitoK(ATP) from brain and liver. Three independent methods indicate that brain mitochondria contain six to seven times more mitoK(ATP) per milligram of mitochondrial protein than liver or heart.

Immobilized RNA switches for the analysis of complex chemical and biological mixtures

A prototype biosensor array has been assembled from engineered RNA molecular switches that undergo ribozyme-mediated self-cleavage when triggered by specific effectors. Each type of switch is prepared with a 5'-thiotriphosphate moiety that permits immobilization on gold to form individually addressable pixels. The ribozymes comprising each pixel become active only when presented with their corresponding effector, such that each type of switch serves as a specific analyte sensor. An addressed array created with seven different RNA switches was used to report the status of targets in complex mixtures containing metal ion, enzyme cofactor, metabolite, and drug analytes. The RNA switch array also was used to determine the phenotypes of Escherichia coli strains for adenylate cyclase function by detecting naturally produced 3',5'- cyclic adenosine monophosphate (cAMP) in bacterial culture media.

Bioenergetic consequences of opening the ATP-sensitive K(+) channel of heart mitochondria

There is an emerging consensus that pharmacological opening of the mitochondrial ATP-sensitive K(+) (K(ATP)) channel protects the heart against ischemia-reperfusion damage; however, there are widely divergent views on the effects of openers on isolated heart mitochondria. We have examined the effects of diazoxide and pinacidil on the bioenergetic properties of rat heart mitochondria. As expected of hydrophobic compounds, these drugs have toxic, as well as pharmacological, effects on mitochondria. Both drugs inhibit respiration and increase membrane proton permeability as a function of concentration, causing a decrease in mitochondrial membrane potential and a consequent decrease in Ca(2+) uptake, but these effects are not caused by opening mitochondrial K(ATP) channels. In pharmacological doses (<50 microM), both drugs open mitochondrial K(ATP) channels, and resulting changes in membrane potential and respiration are minimal. The increased K(+) influx associated with mitochondrial K(ATP) channel opening is approximately 30 nmol. min(-1). mg(-1), a very low rate that will depolarize by only 1-2 mV. However, this increase in K(+) influx causes a significant increase in matrix volume. The volume increase is sufficient to reverse matrix contraction caused by oxidative phosphorylation and can be observed even when respiration is inhibited and the membrane potential is supported by ATP hydrolysis, conditions expected during ischemia. Thus opening mitochondrial K(ATP) channels has little direct effect on respiration, membrane potential, or Ca(2+) uptake but has important effects on matrix and intermembrane space volumes.

Multidrug resistance-related transport proteins in isolated human brain microvessels and in cells cultured from these isolates

The multidrug transporter, P-glycoprotein (Pgp), at the blood-brain barrier is thought to be important for limiting access of toxic agents to the brain, but controversy surrounds its cellular location, whether on endothelium or on adjacent astrocyte foot processes. In the present study, the distribution of protein and mRNA for Pgp and for another transporter, multidrug resistance-associated protein (MRP), is compared with that for the endothelial marker, platelet-endothelial cell adhesion molecule-1 (PECAM-1) and for the astrocyte-derived glial fibrillary acidic protein (GFAP) in microvessels isolated from human brain and in cells grown from these microvessels. Activities of the multidrug transporters are assessed in the cultured cells from the effects of transport inhibitors on intracellular [3H]vincristine accumulation. The isolated microvessels show strong immunocytochemical staining for Pgp and PECAM-1 and little or no staining for GFAP and MRP, and they contain mRNAs detectable by RT-PCR encoding only Pgp and PECAM-1, but not GFAP or MRP. Thus, Pgp may well be synthesised and expressed on cells within the microvessels rather than on adherent astrocyte foot processes. In cells grown from the microvessels, although PECAM-1 remains, Pgp expression decreases and MRP appears. Evidence suggests these multidrug transporters are functionally active in the cultured cells.

Changes in anion permeability following hypotonic challenge in rat brain endothelial cells: different responses in primary cultures and in immortalised RBE4 cells

Hypotonicity-induced anion permeability changes were investigated but not detected in immortalised (RBE4) rat brain endothelial cells using iodide efflux measurements. Large, rapid increases were however observed in primary cultured cells. Both cell types were reinvestigated following culture in a common growth factor-depleted medium. Responses were still undetectable in the immortalised RBE4 cells. Reduced responses were observed in the primary cultured cells that also showed altered morphology and decreased activity of another transporter, P-glycoprotein. Thus both immortalisation and different culture conditions may alter functional expression in these cells of transporters involved in hypotonicity-induced anion permeability changes.