Lassa fever research priorities: towards effective medical countermeasures by the end of the decade.

In 2016, WHO designated Lassa fever a priority disease for epidemic preparedness as part of the WHO Blueprint for Action to Prevent Epidemics. One aspect of preparedness is to promote development of effective medical countermeasures (ie, diagnostics, therapeutics, and vaccines) against Lassa fever. Diagnostic testing for Lassa fever has important limitations and key advancements are needed to ensure rapid and accurate diagnosis. Additionally, the only treatment available for Lassa fever is ribavirin, but controversy exists regarding its effectiveness. Finally, no licensed vaccines are available for the prevention and control of Lassa fever. Ongoing epidemiological and behavioural studies are also crucial in providing actionable information for medical countermeasure development, use, and effectiveness in preventing and treating Lassa fever. This Personal View provides current research priorities for development of Lassa fever medical countermeasures based on literature published primarily in the last 5 years and consensus opinion of 20 subject matter experts with broad experience in public health or the development of diagnostics, therapeutics, and vaccines for Lassa fever. These priorities provide an important framework to ensure that Lassa fever medical countermeasures are developed and readily available for use in endemic and at-risk areas by the end of the decade.

Identification of cancer types from gene expressions using learning techniques.

Tumor is the major cause of death all around the world in recent days. Early detection and prediction of a cancer type are important for a patient's well-being. Functional genomic data has recently been used in the effective and early detection of cancer. According to previous research, the use of microarray data in cancer prediction has evidenced two main problems as high dimensionality and limited sample size. Several researchers have used numerous statistical and machine learning-based methods to classify cancer types but still, limitations are there which makes cancer classification a difficult job. Deep Learning (DL) and Convolutional Neural Networks (CNN) have been proven with effective analyses of unstructured data including gene expression data. In the proposed method gene expression data for five types of cancer is collected from The Cancer Genome Atlas (TCGA). Prominent features are selected using a hybrid Particle Swarm Optimization (PSO) and Random Forest (RF) algorithm followed by the use of Principal Component Analysis (PCA) for dimensionality reduction. Finally, for classification blend of Convolutional Neural Network (CNN) and Bi-directional Long Short Term Memory (Bi-LSTM) is used to predict the target type of cancer. Experimental results demonstrate that accuracy of the proposed method is 96.89%. As compared to existing work, our method outperformed with better results.

SLD with and without ADHD: Comparison of cognitive profiles.

A quarter of children with Specific Learning Disorder (SLD) have a comorbid attention deficit hyperactivity disorder (ADHD), which impacts the testing of intelligence. ADHD is therefore treated before proceeding with the assessment of intelligence. It is expected that the treatment of ADHD will mitigate its effects on intelligence testing. Though this is frequently done in clinical practice, we could not find any study comparing IQ profiles of children having SLD with and without ADHD after treating ADHD to look for any changes between them. Therefore, we planned this study to compare the cognitive profiles of children having SLD with and without ADHD and describe any difference in their profiles. It was a retrospective cross-sectional study. We compared 695 children having SLD with treated ADHD to 721 children having SLD without ADHD on their WISC III profiles. We found that children having SLD with treated ADHD scored significantly lower on Digit Span and Coding. We suggest routine use of Cognitive Working Memory Training, peer tutoring, and task modifications in children having SLD with ADHD along with medicines and remedial education for better outcomes.

Nonhuman Primates Are Protected against Marburg Virus Disease by Vaccination with a Vesicular Stomatitis Virus Vector-Based Vaccine Prepared under Conditions to Allow Advancement to Human Clinical Trials.

Vaccines are needed to disrupt or prevent continued outbreaks of filoviruses in humans across Western and Central Africa, including outbreaks of Marburg virus (MARV). As part of a filovirus vaccine product development plan, it is important to investigate dose response early in preclinical development to identify the dose range that may be optimal for safety, immunogenicity, and efficacy, and perhaps demonstrate that using lower doses is feasible, which will improve product access. To determine the efficacious dose range for a manufacturing-ready live recombinant vesicular stomatitis virus vaccine vector (rVSV∆G-MARV-GP) encoding the MARV glycoprotein (GP), a dose-range study was conducted in cynomolgus macaques. Results showed that a single intramuscular injection with as little as 200 plaque-forming units (PFUs) was 100% efficacious against lethality and prevented development of viremia and clinical pathologies associated with MARV Angola infection. Across the vaccine doses tested, there was nearly a 2000-fold range of anti-MARV glycoprotein (GP) serum IgG titers with seroconversion detectable even at the lowest doses. Virus-neutralizing serum antibodies also were detected in animals vaccinated with the higher vaccine doses indicating that vaccination induced functional antibodies, but that the assay was a less sensitive indicator of seroconversion. Collectively, the data indicates that a relatively wide range of anti-GP serum IgG titers are observed in animals that are protected from disease implying that seroconversion is positively associated with efficacy, but that more extensive immunologic analyses on samples collected from our study as well as future preclinical studies will be valuable in identifying additional immune responses correlated with protection that can serve as markers to monitor in human trials needed to generate data that can support vaccine licensure in the future.

Preclinical immunogenicity and efficacy of a candidate COVID-19 vaccine based on a vesicular stomatitis virus-SARS-CoV-2 chimera.

BACKGROUND: To investigate a vaccine technology with potential to protect against coronavirus disease 2019 (COVID-19) and reduce transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with a single vaccine dose, we developed a SARS-CoV-2 candidate vaccine using the live vesicular stomatitis virus (VSV) chimeric virus approach previously used to develop a licensed Ebola virus vaccine. METHODS: We generated a replication-competent chimeric VSV-SARS-CoV-2 vaccine candidate by replacing the VSV glycoprotein (G) gene with coding sequence for the SARS-CoV-2 Spike glycoprotein (S). Immunogenicity of the lead vaccine candidate (VSV∆G-SARS-CoV-2) was evaluated in cotton rats and golden Syrian hamsters, and protection from SARS-CoV-2 infection also was assessed in hamsters. FINDINGS: VSV∆G-SARS-CoV-2 delivered with a single intramuscular (IM) injection was immunogenic in cotton rats and hamsters and protected hamsters from weight loss following SARS-CoV-2 challenge. When mucosal vaccination was evaluated, cotton rats did not respond to the vaccine, whereas mucosal administration of VSV∆G-SARS-CoV-2 was found to be more immunogenic than IM injection in hamsters and induced immunity that significantly reduced SARS-CoV-2 challenge virus loads in both lung and nasal tissues. INTERPRETATION: VSV∆G-SARS-CoV-2 delivered by IM injection or mucosal administration was immunogenic in golden Syrian hamsters, and both vaccination methods effectively protected the lung from SARS-CoV-2 infection. Hamsters vaccinated by mucosal application of VSV∆G-SARS-CoV-2 also developed immunity that controlled SARS-CoV-2 replication in nasal tissue. FUNDING: The study was funded by Merck Sharp & Dohme, Corp., a subsidiary of Merck & Co., Inc., Rahway, NJ, USA, and The International AIDS Vaccine Initiative, Inc. (IAVI), New York, USA. Parts of this research was supported by the Biomedical Advanced Research and Development Authority (BARDA) and the Defense Threat Reduction Agency (DTRA) of the US Department of Defense.

Association of Race/Ethnicity and Social Determinants with Rehospitalization for Mental Health Conditions at Acute Care Children's Hospitals.

OBJECTIVE: To evaluate associations of race/ethnicity and social determinants with 90-day rehospitalization for mental health conditions to acute care nonpsychiatric children's hospitals. STUDY DESIGN: We conducted a retrospective cohort analysis of mental health hospitalizations for children aged 5-18 years from 2016 to 2018 at 32 freestanding US children's hospitals using the Children's Hospital Association's Pediatric Health Information System database to assess the association of race/ethnicity and social determinants (insurance payer, neighborhood median household income, and rurality of patient home location) with 90-day rehospitalization. Risk factors for rehospitalization were modeled using mixed-effects multivariable logistic regression. RESULTS: Among 23 556 index hospitalizations, there were 1382 mental health rehospitalizations (5.9%) within 90 days. Non-Hispanic Black children were 26% more likely to be rehospitalized than non-Hispanic White children (aOR 1.26, 95% CI 1.08-1.48). Those with government insurance were 18% more likely to be rehospitalized than those with private insurance (aOR 1.18, 95% CI 1.04-1.34). In contrast, those living in a suburban location were 22% less likely to be rehospitalized than those living in an urban location (suburban: aOR 0.78, 95% CI 0.63-0.97). CONCLUSIONS: Non-Hispanic Black children and those with public insurance were at greatest risk for 90-day rehospitalization, and risk was lower in those residing in suburban locations. Future work should focus on upstream interventions that will best attenuate social disparities to promote equity in pediatric mental healthcare.

A Randomized Controlled Trial of the Efficacy of Systemic Enzymes and Probiotics in the Resolution of Post-COVID Fatigue.

Muscle fatigue and cognitive disturbances persist in patients after recovery from acute COVID-19 disease. However, there are no specific treatments for post-COVID fatigue. Objective: To evaluate the efficacy and safety of the health supplements ImmunoSEB (systemic enzyme complex) and ProbioSEB CSC3 (probiotic complex) in patients suffering from COVID-19 induced fatigue. A randomized, multicentric, double blind, placebo-controlled trial was conducted in 200 patients with a complaint of post-COVID fatigue. The test arm (n = 100) received the oral supplements for 14 days and the control arm (n = 100) received a placebo. Treatment efficacy was compared using the Chalder Fatigue scale (CFQ-11), at various time points from days 1 to 14. The supplemental treatment resulted in resolution of fatigue in a greater percentage of subjects in the test vs. the control arm (91% vs. 15%) on day 14. Subjects in the test arm showed a significantly greater reduction in total as well as physical and mental fatigue scores at all time points vs. the control arm. The supplements were well tolerated with no adverse events reported. This study demonstrates that a 14 days supplementation of ImmunoSEB + ProbioSEB CSC3 resolves post-COVID-19 fatigue and can improve patients' functional status and quality of life.

Global health on the front lines: an innovative medical student elective combining education and service during the COVID-19 pandemic.

BACKGROUND: An innovative medical student elective combined student-directed, faculty-supported online learning with COVID-19 response field placements. This study evaluated students' experience in the course, the curriculum content and format, and its short-term impact on students' knowledge and attitudes around COVID-19. METHODS: Students responded to discussion board prompts throughout the course and submitted pre-/post-course reflections. Pre-/post-course questionnaires assessed pandemic knowledge and attitudes using 4-point Likert scales. Authors collected aggregate data on enrollment, discussion posts, field placements, and scholarly work resulting from course activities. After the elective, authors conducted a focus group with a convenience sample of 6 participants. Institutional elective evaluation data was included in analysis. Authors analyzed questionnaire data with summary statistics and paired t-tests comparing knowledge and attitudes before and after the elective. Reflection pieces, discussion posts, and focus group data were analyzed using content analysis with a phenomenological approach. RESULTS: Twenty-seven students enrolled. Each student posted an average of 2.4 original discussion posts and 3.1 responses. Mean knowledge score increased from 43.8 to 60.8% (p <  0.001) between pre- and post-course questionnaires. Knowledge self-assessment also increased (2.4 vs. 3.5 on Likert scale, p <  0.0001), and students reported increased engagement in the pandemic response (2.7 vs. 3.6, p <  0.0001). Students reported increased fluency in discussing the pandemic and increased appreciation for the field of public health. There was no difference in students' level of anxiety about the pandemic after course participation (3.0 vs. 3.1, p = 0.53). Twelve students (44.4%) completed the institutional evaluation. All rated the course "very good" or "excellent." Students favorably reviewed the field placements, suggested readings, self-directed research, and learning from peers. They suggested more clearly defined expectations and improved balance between volunteer and educational hours. CONCLUSIONS: The elective was well-received by students, achieved stated objectives, and garnered public attention. Course leadership should monitor students' time commitment closely in service-learning settings to ensure appropriate balance of service and education. Student engagement in a disaster response is insufficient to address anxiety related to the disaster; future course iterations should include a focus on self-care during times of crisis. This educational innovation could serve as a model for medical schools globally.

Pregnant women & vaccines against emerging epidemic threats: Ethics guidance for preparedness, research, and response.

Zika virus, influenza, and Ebola have called attention to the ways in which infectious disease outbreaks can severely - and at times uniquely - affect the health interests of pregnant women and their offspring. These examples also highlight the critical need to proactively consider pregnant women and their offspring in vaccine research and response efforts to combat emerging and re-emerging infectious diseases. Historically, pregnant women and their offspring have been largely excluded from research agendas and investment strategies for vaccines against epidemic threats, which in turn can lead to exclusion from future vaccine campaigns amidst outbreaks. This state of affairs is profoundly unjust to pregnant women and their offspring, and deeply problematic from the standpoint of public health. To ensure that the needs of pregnant women and their offspring are fairly addressed, new approaches to public health preparedness, vaccine research and development, and vaccine delivery are required. This Guidance offers 22 concrete recommendations that provide a roadmap for the ethically responsible, socially just, and respectful inclusion of the interests of pregnant women in the development and deployment of vaccines against emerging pathogens. The Guidance was developed by the Pregnancy Research Ethics for Vaccines, Epidemics, and New Technologies (PREVENT) Working Group - a multidisciplinary, international team of 17 experts specializing in bioethics, maternal immunization, maternal-fetal medicine, obstetrics, pediatrics, philosophy, public health, and vaccine research and policy - in consultation with a variety of external experts and stakeholders.

Serratiopeptidase: Insights into the therapeutic applications.

Therapeutic applications of enzymes have been widely accepted in clinical practices for decades. Proteolytic enzymes in particular, have been used for the treatment of diseases and disorders. Serratiopeptidase is a proteolytic enzyme having immense applications in therapeutic areas which have been validated by several in vitro, in vivo, and clinical studies as well as through anecdotal evidences. These applications are attributable to its versatile properties including anti-inflammatory, anti-biofilm, analgesic, anti-edemic, and fibrinolytic effects. The significant impact of serratiopeptidase reported needs to be backed by more scientific data. This review encompasses the details of therapeutic applications of serratiopeptidase based on available in vitro, in vivo, and clinical studies. We found some strong evidences regarding the efficacy of serratiopeptidase. However data on safety, tolerability, and its mechanism of action need detailing. This review aims to further explore the available literature on serratiopeptidase as well as provide scientific details for existing applications.

Prevalence of Clinically Significant Drug-Drug Interactions Across US Children's Hospitals.

BACKGROUND: Little is known about the prescribing of medications with potential drug-drug interactions (DDIs) in the pediatric population. The objective of this study was to determine the prevalence and variation of prescribing medications with clinically significant DDIs across children's hospitals in the United States. METHODS: We performed a retrospective cohort study of patients <26 years of age who were discharged from 1 of 52 US children's hospitals between January 2016 and December 2018. Fifty-three drug pairings with clinically significant DDIs in children were evaluated. We identified patient-level risk factors associated with DDI using multivariable logistic regression. Adjusted hospital-level rates of DDI exposure were derived by using a generalized linear mixed-effects model, and DDI exposure variations were examined across individual hospitals. RESULTS: Across 52 children's hospitals, 47 414 (2.0%) hospitalizations included exposure to a DDI pairing (34.9 per 1000 patient-days) during the study period. One-quarter of pairings were considered contraindicated (risk grade X). After adjusting for hospital and clinical factors, there was wide variation in the percentage of DDI prescribing across hospitals, ranging from 1.05% to 4.92%. There was also substantial hospital-level variation of exposures to individual drug pairings. Increasing age, number of complex chronic conditions, length of stay, and surgical encounters were independently associated with an increased odds of DDI exposure. CONCLUSIONS: Patients hospitalized at US children's hospitals are frequently exposed to medications with clinically significant DDIs. Exposure risk varied substantially across hospitals. Further study is needed to determine the rate of adverse events due to DDI exposures and factors amenable for interventions promoting safer medication use.

"Agar Cell-Suspension": A Novel Technique for Processing Clear Specimens.

CONTEXT: Clear cytology specimens are processed by cytocentrifugation which is preferred over membrane filters (MF). Although both techniques are expensive, cytocentrifugation is less tedious and may cause cellular distortion. AIM: To standardize "Agar cell-suspension" (ACS) an innovative, simple, cost-effective technique to process clear specimens. METHODS AND MATERIALS: About 93 clear specimens (65 urine, 15 effusion, 12 CSF, and 1 bronchial lavage) were processed by both cytocentrifugation and ACS. The sample was centrifuged in two tubes; one was used for ACS and other for cytocentrifugation. ACS smears were prepared by mixing one drop of 0.5% agar solution with the last drop of the centrifugate. Smears were fixed in methanol and stained by Papanicolaou staining method. ACS smears were compared with cytocentrifuged smears (CS) and evaluated for cellularity, cytomorphology preservation, staining quality, time, and cost. RESULTS: As compared to CS smears, ACS smears showed better cellularity in 16.1%, comparable in 53.7%, and less in 30.1%. All ACS smears (100%) showed well-preserved cytomorphology as compared to 96.7% CS. Staining quality was optimal in 96.7% ACS smears against 91.3% CS. Both techniques took equal time. The additional cost of ACS was only 0.03 INR compared to 12.50 INR for CS. CONCLUSIONS: ACS is an innovative, simple, easy, and cost-effective technique for processing clear specimens. It gives equally good results comparable to cytocentrifugation in terms of cellularity and staining quality. ACS does not cause cell distortion or air-drying as seen in some CS. Thus, ACS is a superior alternative to cytocentrifugation.

Unprecedented pace and partnerships: the story of and lessons learned from one Ebola vaccine program.

INTRODUCTION: The Ebola epidemic in West Africa from 2014 to 2016 was unique in its size, location, and duration; this article reviews the experiences and lessons learned for one vaccine candidate developed during the outbreak and discusses critical gaps that still exist today which will need to be addressed for successful end to end emerging infectious disease vaccine product development in the future. AREAS COVERED: Through the formation of numerous international partnerships, the rVSVΔG-ZEBOV-GP vaccine advanced through Phase I/II/III clinical trials which resulted in favorable Phase III efficacy results. Key lessons learned that could be used to facilitate future vaccine development efforts include sufficient preclinical work in relevant animal models, innovative partnerships created to pool resources and expertise, and 'hyper' coordination and communication among partners to build trust and ensure an adequate regulatory package needed to license a vaccine. EXPERT COMMENTARY: As evidenced by the 2014-2016 outbreak in West Africa as well as the two other most recent outbreaks in the Democratic Republic of the Congo in 2018, there is an urgent need to develop new models for emerging infection vaccine development where trusted partners come together and where the development of vaccines is a shared responsibility conducted in advance of the next crisis.

Time to redefine the intramammary lymph node as a separate entity?

The lymphatic drainage for the majority of primary breast tumors is to the axillary lymph nodes (ALNs). Some, however, drain to the so-called extra-axillary basins, namely the internal mammary, supra- and infraclavicular regions. Another potential drainage route includes the intramammary lymph nodes (IMLNs). Current guidance suggests IMLNs should be considered as part of the axillary group, potentially affecting axillary management. However, due to evolution in imaging and advancement in technology, IMLNs may now be distinguished more accurately pre-operatively. There are currently no published guidelines for the management of IMLNs in the United Kingdom. The authors suggest that it is time to reclassify IMLNs as a separate focus of cancer and treat it as a separate entity. Clin. Anat. 31:684-687, 2018. © 2018 Wiley Periodicals, Inc.

Prediction of Recurrent Clostridium Difficile Infection Using Comprehensive Electronic Medical Records in an Integrated Healthcare Delivery System.

BACKGROUND Predicting recurrent Clostridium difficile infection (rCDI) remains difficult. METHODS: We employed a retrospective cohort design. Granular electronic medical record (EMR) data had been collected from patients hospitalized at 21 Kaiser Permanente Northern California hospitals. The derivation dataset (2007-2013) included data from 9,386 patients who experienced incident CDI (iCDI) and 1,311 who experienced their first CDI recurrences (rCDI). The validation dataset (2014) included data from 1,865 patients who experienced incident CDI and 144 who experienced rCDI. Using multiple techniques, including machine learning, we evaluated more than 150 potential predictors. Our final analyses evaluated 3 models with varying degrees of complexity and 1 previously published model. RESULTS Despite having a large multicenter cohort and access to granular EMR data (eg, vital signs, and laboratory test results), none of the models discriminated well (c statistics, 0.591-0.605), had good calibration, or had good explanatory power. CONCLUSIONS Our ability to predict rCDI remains limited. Given currently available EMR technology, improvements in prediction will require incorporating new variables because currently available data elements lack adequate explanatory power. Infect Control Hosp Epidemiol 2017;38:1196-1203.

Reducing DNA context dependence in bacterial promoters.

Variation in the DNA sequence upstream of bacterial promoters is known to affect the expression levels of the products they regulate, sometimes dramatically. While neutral synthetic insulator sequences have been found to buffer promoters from upstream DNA context, there are no established methods for designing effective insulator sequences with predictable effects on expression levels. We address this problem with Degenerate Insulation Screening (DIS), a novel method based on a randomized 36-nucleotide insulator library and a simple, high-throughput, flow-cytometry-based screen that randomly samples from a library of 436 potential insulated promoters. The results of this screen can then be compared against a reference uninsulated device to select a set of insulated promoters providing a precise level of expression. We verify this method by insulating the constitutive, inducible, and repressible promotors of a four transcriptional-unit inverter (NOT-gate) circuit, finding both that order dependence is largely eliminated by insulation and that circuit performance is also significantly improved, with a 5.8-fold mean improvement in on/off ratio.

Antibodies to Toxin B Are Protective Against Clostridium difficile Infection Recurrence.

BACKGROUND: Although newer studies have evaluated risk factors for recurrent Clostridium difficile infection (CDI), the vast majority did not measure important biomarkers such as endogenous anti-toxin A and anti-toxin B antibody levels. METHODS: Data from the placebo group of a phase 2 trial testing monoclonal antibodies to C. difficile toxins A and B for preventing CDI recurrence (rCDI) were analyzed to assess risk factors associated with rCDI. Patients with symptomatic CDI taking metronidazole or vancomycin were enrolled. The primary outcome was rCDI within 84 days of treatment start. Univariate and multivariate logistic regression was used to examine associations between potential risk factors and rCDI. At baseline, demographic and clinical characteristics were recorded; endogenous antibody levels were assessed using 2 enzyme-linked immunosorbent assays. RESULTS: A predictor of recurrence was age ≥65 years, and an antibody-mediated immune response to toxin B appears to be protective against rCDI. CONCLUSIONS: Our findings demonstrate the importance of clinical as well as immunological risk factors in rCDI and provide more robust evidence for the protective effects of antibody to toxin B in the prevention of rCDI. CLINICAL TRIALS REGISTRATION: NCT00350298.

Epidemiological and economic burden of Clostridium difficile in the United States: estimates from a modeling approach.

BACKGROUND: Despite a large increase in Clostridium difficile infection (CDI) severity, morbidity and mortality in the US since the early 2000s, CDI burden estimates have had limited generalizability and comparability due to widely varying clinical settings, populations, or study designs. METHODS: A decision-analytic model incorporating key input parameters important in CDI epidemiology was developed to estimate the annual number of initial and recurrent CDI cases, attributable and all-cause deaths, economic burden in the general population, and specific number of high-risk patients in different healthcare settings and the community in the US. Economic burden was calculated adopting a societal perspective using a bottom-up approach that identified healthcare resources consumed in the management of CDI. RESULTS: Annually, a total of 606,058 (439,237 initial and 166,821 recurrent) episodes of CDI were predicted in 2014: 34.3 % arose from community exposure. Over 44,500 CDI-attributable deaths in 2014 were estimated to occur. High-risk susceptible individuals representing 5 % of the total hospital population accounted for 23 % of hospitalized CDI patients. The economic cost of CDI was $5.4 billion ($4.7 billion (86.7 %) in healthcare settings; $725 million (13.3 %) in the community), mostly due to hospitalization. CONCLUSIONS: A modeling framework provides more comprehensive and detailed national-level estimates of CDI cases, recurrences, deaths and cost in different patient groups than currently available from separate individual studies. As new treatments for CDI are developed, this model can provide reliable estimates to better focus healthcare resources to those specific age-groups, risk-groups, and care settings in the US where they are most needed. (Trial Identifier ClinicaTrials.gov: NCT01241552).

Interaction of polyphenol oxidase of Solanum tuberosum with ß-cyclodextrin: Process details and applications.

Polysaccharides differing in structure and chemical nature were screened for their ability to bind non-covalently with polyphenol oxidase (PPO) from potato (as a model) and their effect on enzyme activity. All the polysaccharides selected inhibited the PPO but ß-cyclodextrin showed maximum inhibition under optimum conditions. Process details for the inhibition of PPO were studied with respect to concentration of ß-cyclodextrin, temperature, pH, and time. Higher inhibition constant and lower half life was obtained at 40 °C than at 30 °C in the presence of inhibitor. ß-Cyclodextrin showed mixed type of inhibition of PPO. ß-Cyclodextrin was further exploited as anti-browning agent in selected fruit juices. It not only showed a significant anti-browning effect on freshly prepared potato juice but was also effective in other fruit juices. Better effect was seen in pineapple, apple and pear as compared to banana, sugarcane and guava fruit juices.

Interaction of carbohydrates with alcohol dehydrogenase: Effect on enzyme activity.

Alcohol dehydrogenase was covalently conjugated with three different oxidized carbohydrates i.e., glucose, starch and pectin. All the carbohydrates inhibited the enzyme. The inhibition was studied with respect to the inhibition rate constant, involvement of thiol groups in the binding, and structural changes in the enzyme. The enzyme activity decreased to half of its original activity at the concentration of 2 mg/mL of pectin, 4 mg/mL of glucose and 10 mg/mL of starch within 10 min at pH 7. This study showed oxidized pectin to be a potent inhibitor of alcohol dehydrogenase followed by glucose and starch. Along with the aldehyde-amino group interaction, thiol groups were also involved in the binding between alcohol dehydrogenase and carbohydrates. The structural changes occurring on binding of alcohol dehydrogenase with oxidized carbohydrates was also confirmed by fluorescence spectrophotometry. Oxidized carbohydrates could thus be used as potential inhibitors of alcohol dehydrogenase.