Robust gut associated vaccine-specific antibody-secreting cell responses are detected at the mucosal surface of Bangladeshi subjects after immunization with an oral killed bivalent V. cholerae O1/O139 whole cell cholera vaccine: Comparison with other mucosal and systemic responses

The emergence of V. cholerae O139 serogroup of V. cholerae capable of causing severe dehydrating cholera has over the decade led to efforts in formulation of vaccines to protect against this pathogen. Although the prevalence of diarrhea due to V. cholerae O139 has recorded a decrease, efforts on vaccine development continues to formulate an oral vaccine capable of stimulating the gut mucosal system. We have studied the mucosal immunogenicity in Bangladeshi adults to a killed whole cell (WC) bivalent cholera vaccine composed of V. cholerae O139 as well as V. cholerae O1 strains together with the recombinant cholera toxin B subunit (CTB) (WC-O1/O139/CTB) and compared the immune responses to that obtained with the licensed monovalent cholera vaccine, Dukoral (WC-O1/CTB). Direct estimation of the WC-O1/O139/CTB vaccine-specific mucosal responses were carried out using lymphocytes isolated from duodenal biopsies, intestinal lavage fluid and feces. The vaccine induced robust antibody-secreting cell responses in the duodenum specific to CTB as well as the O1 and O139 lipopolysaccharide (LPS). Magnitude of response was higher in the gut than in the circulation in all three antibody isotypes. The CTB and LPS-specific mucosal antibody responses were also seen in intestinal lavage fluid and fecal extracts. Vibriocidal antibody responses in plasma were observed to both the V. cholerae O1 and O139 serogroups (76% and 57% response rates, respectively). Plasma IgA and IgG responses to CTB and IgA responses to both O1 and O139 LPS were elevated. The immune responses were comparable to that seen to the monovalent WC-O1/CTB recipients in all components studied. Overall, the bivalent cholera vaccine induces strong mucosal responses and the addition of the O139 component does not interfere with the responses to the licensed vaccine Dukoral. This sets the ground for testing such vaccines in large field trials in Bangladesh and also demonstrates that addition of other vibrio components to the existing cholera vaccine does not alter the responses to the O1 vaccine components.     

Evidence for the presence of R250G mutation at the ATPase domain of topoisomerase II in an arsenite-resistant Leishmania donovani exhibiting a differential drug inhibition profile

Resistance to operational drugs is a major barrier to successful antileishmanial chemotherapy that demands development of novel drug intervention strategies based on rational approaches. Model drug resistance phenotypes, such as arsenite resistance used in the current study, facilitate our understanding of the mechanism of drug resistance and assist in identifying new drug target(s). The current study was undertaken to investigate the sensitivity of topoisomerase II (topo II) of arsenite-sensitive (Ld-Wt) and -resistant (Ld-As20) Leishmania donovani to antileishmanial/anti-topo II agents. The effect of antileishmanial/anti-topo II drugs on partially purified topo II enzyme from Ld-Wt and Ld-As20 revealed differential inhibition of topo II decatenation activity for the two strains, with a lower amount of drug required to inhibit activity by 50% in Ld-Wt compared with Ld-As20. Comparison of topo II sequences from both strains indicated a point mutation, R250G, in the ATPase domain of the resistant strain. Furthermore, the Arg-250 of the ATPase domain of topo II was observed to be conserved throughout different species of Leishmania. Variation in the topo II gene sequence between Ld-Wt and Ld-As20 is envisaged to be responsible for the differential behaviour of the enzymes from the two sources.     

Synthesis, characterization, and light-controlled antibiotic application of a composite material derived from polyurethane and silica xerogel with embedded photoactive manganese nitrosyl

The synthesis of a light-sensitive polyurethane-based composite material (PUX-NO) is described. In its polyurethane medium, PUX-NO contains entrapped silica xerogel particles in which a photoactive manganese nitrosyl has been incorporated. Green flexible films of PUX-NO readily release nitric oxide (NO) only when exposed to low power (mW) visible light. Incorporation of the nitrosyl in the xerogel not only retains the nitrosyl (NO donor) within the composite material but also provides the right extent of hydration. Pre-swelled films of PUX-NO have water content close to 30 Wt % and such films can be stored for months under slightly moist condition without loss in NO-delivering capacity. The NO-releasing parameters of the film have been determined. The NO-releasing capacity of PUX-NO films can be conveniently altered by changing the amount of the nitrosyl as well as the thickness of the films. Patches of PUX-NO film have been successfully employed to reduce drastically bacterial loads of both gram-positive and gram-negative bacteria including methicillin-resistant Staphylococcus aureus and Acinetobacter baumannii under the total control of light. Effective control of infections by these bacterial pathogens via delivery of proper doses of NO only to the sites of infection appears feasible with PUX-NO films.     

Inactivation of Apc in the mouse prostate causes prostate carcinoma

Alterations of the Wnt/beta-catenin signaling pathway are positively associated with the development and progression of human cancer, including carcinoma of the prostate. To determine the role of activated Wnt/beta-catenin signaling in mouse prostate carcinogenesis, we created a mouse prostate tumor model using probasin-Cre-mediated deletion of Apc. Prostate tumors induced by the deletion of Apc have elevated levels of beta-catenin protein and are highly proliferative. Tumor formation is fully penetrant and follows a consistent pattern of progression. Hyperplasia is observed as early as 4.5 weeks of age, and adenocarcinoma is observed by 7 months. Continued tumor growth usually necessitated sacrifice between 12 and 15 months of age. Despite the high proliferation rate, we have not observed metastasis of these tumors to the lymph nodes or other organs. Surgical castration of 6-week-old mice inhibited tumor formation, and castration of mice with more advanced tumors resulted in the partial regression of specific prostate glands. However, significant areas of carcinoma remained 2 months postcastration, suggesting that tumors induced by Apc loss of function are capable of growth under conditions of androgen depletion. We conclude that the prostate-specific deletion of Apc and the increased expression of beta-catenin associated with prostate carcinoma suggests a role for beta-catenin in prostate cancer and offers an appropriate animal model to investigate the interaction of Wnt signaling with other genetic and epigenetic signals in prostate carcinogenesis.     

Preparation and Enhancing Properties of pH-Sensitive Hydrogel in Light of Gum Ghatti-cl-poly(acrylic acid)/ – o-MWCNT for Sodium Diclofenac Drug Release

Gum ghatti (GG) is used as a biopolymer, acrylic acid (AA) is used as a synthetic monomer, ammonium persulphate (APS) is used as an initiator, and methylene bis-acrylamide (MBA) is used as a cross-linker in the current study to create gum ghatti-cl-poly(acrylic acid)-o-MWCNT hydrogels. The –o-MWCNT (0, 10, 20, 30, 40, and 50 mg) is added to the hydrogel as a filler. Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and X-ray diffraction (XRD) analyses are used to characterize the crosslinked hydrogels. The successful polymerization of the graft is confirmed by these spectroscopic studies. Sodium diclofenac (SD) as a model drug is utilized. Swelling tests are also conducted at pH 6.8 on all prepared hydrogels. In a similar manner, all hydrogel preparations are subjected to an in vitro study at neutral (pH 7.4), acidic (pH 1.2), and basic (pH 9.2) mediums, and a higher drug release is observed at pH 7.4. The Higuchi model, the Korsmeyer–Peppas model, and various zero-order and first-order kinetics are utilized in the investigation of the drug release order mechanism from the hydrogels. The drug release data favor the Korsmeyer–Peppas model, which describes the “n” diffusion exponent that controls the drug release mechanism from synthesized hydrogels. The “n” values control the Fickian diffusion (Case-I diffusional) like coupled diffusion (0.45 ≤ n). According to the results presented here, GGAACNT-based hydrogels can be used in biomedical fields, especially for controlled drug release.     

Ambulatory follow-up among publicly insured children discharged from the emergency department

Background

While children discharged from the emergency department (ED) are frequently advised to follow up with ambulatory care providers, the extent to which this occurs is unknown. We sought to characterize the proportion of publicly insured children who have an ambulatory visit following ED discharge, identify factors associated with ambulatory follow-up, and evaluate the association of ambulatory follow-up with subsequent hospital-based health care utilization.

Methods

We performed a cross-sectional study of pediatric (<18 years) encounters during 2019 included in the IBM Watson Medicaid MarketScan claims database from seven U.S. states. Our primary outcome was an ambulatory follow-up visit within 7 days of ED discharge. Secondary outcomes were 7-day ED return visits and hospitalizations. Logistic regression and Cox proportional hazards were used for multivariable modeling.

Results

We included 1,408,406 index ED encounters (median age 5 years, IQR 2–10 years), for which a 7-day ambulatory visit occurred in 280,602 (19.9%). Conditions with the highest proportion of 7-day ambulatory follow-up included seizures (36.4%); allergic, immunologic, and rheumatologic diseases (24.6%); other gastrointestinal diseases (24.5%); and fever (24.1%). Ambulatory follow-up was associated with younger age, Hispanic ethnicity, weekend ED discharge, ambulatory encounters prior to the ED visit, and diagnostic testing performed during the ED encounter. Ambulatory follow-up was inversely associated with Black race and ambulatory care–sensitive or complex chronic conditions. In Cox models, ambulatory follow-up was associated with a higher hazard ratio (HR) of subsequent ED return (HR range 1.32–1.65) visit and hospitalization (HR range 3.10–4.03).

Conclusions

One-fifth of children discharged from the ED have an ambulatory visit within 7 days, which varied by patient characteristics and diagnoses. Children with ambulatory follow-up have a greater subsequent health care utilization, including subsequent ED visit and/or hospitalization. These findings identify the need to further research the role and costs associated with routine post-ED visit follow-up.