Immunogenicity, clinical efficacy and safety of additional second COVID-19 booster vaccines against Omicron and its subvariants: A systematic review.

The Omicron variant of severe acute respiratory syndrome coronavirus 2 is a new variant of concern (VOC) and an emerging subvariant that exhibits heightened infectivity, transmissibility, and immune evasion, escalating the incidence of moderate to severe coronavirus disease 2019 (COVID-19). It resists monoclonal antibodies and diminishes vaccine efficacy. Notably, new sublineages have outpaced earlier predominant sublineages. Although the primary vaccination series and initial boosters were robust against previous VOCs, their efficacy waned against Omicron and its subvariants. In this systematic review, we assessed real-world evidence on the immunogenicity, clinical efficacy, and safety of a second booster or fourth COVID-19 vaccine dose against the Omicron VOC and its subvariants. A comprehensive literature search was conducted in Medline/PubMed, Google Scholar, bioRxiv, and medRxiv, and relevant studies published between 2022 and 30 May 2023 were reviewed. We found a total of 40 relevant articles focusing on a second booster dose for COVID-19, including clinical trials and observational studies, involving 3,972,856 patients. The results consistently revealed that an additional second booster dose restored and prolonged waning immunity, activating both humoral and cellular responses against Omicron and its subvariants. A second booster treatment correlated with enduring protection against COVID-19, notably preventing substantial symptomatic disease and mortality associated with severe Omicron infection. Both monovalent messenger RNA (mRNA) and nonmRNA vaccines demonstrated similar efficacy and safety, with bivalent mRNA vaccines exhibiting broader protection against emerging subvariants of Omicron. The safety profiles of second booster were favourable with only mild systemic and local symptoms reported in some recipients. In conclusion, this systematic review underscores the additional COVID-19 vaccine boosters, particularly with bivalent or multivalent mRNA vaccines, for countering the highly infectious emerging subvariants of Omicron.

Expression and functional analysis of a recombinant aquaporin Z from Antarctic Pseudomonas sp. AMS3.

Aquaporin (AQP) is a water channel protein from the family of transmembrane proteins which facilitates the movement of water across the cell membrane. It is ubiquitous in nature, however the understanding of the water transport mechanism, especially for AQPs in microbes adapted to low temperatures, remains limited. AQP also has been recognized for its ability to be used for water filtration, but knowledge of the biochemical features necessary for its potential applications in industrial processes has been lacking. Therefore, this research was conducted to express, extract, solubilize, purify, and study the functional adaptations of the aquaporin Z family from Pseudomonas sp. AMS3 via molecular approaches. In this study, AqpZ1 AMS3 was successfully subcloned and expressed in E. coli BL21 (DE3) as a recombinant protein. The AqpZ1 AMS3 gene was expressed under optimized conditions and the best optimized condition for the AQP was in 0.5 mM IPTG incubated at 25°C for 20 h induction time. A zwitterionic mild detergent [(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate was the suitable surfactant for the protein solubilization. The protein was then purified via affinity chromatography. Liposome and proteoliposome was reconstituted to determine the particle size using dynamic light scattering. This information obtained from this psychrophilic AQP identified provides new insights into the structural adaptation of this protein at low temperatures and could be useful for low temperature application and molecular engineering purposes in the future.

Antibiotic-associated Gut Dysbiosis.

The human gut microbiota plays a crucial role in maintaining overall health. However, the widespread use of antibiotics has raised concerns about its impact on the microbial ecosystem. This review explores the multifaceted relationship between antibiotics and gut dysbiosis, highlighting the mechanisms underlying these interactions and their implications for human health. Antibiotics, while invaluable in treating infections, disrupt the gut microbiota by indiscriminately targeting both harmful and beneficial microorganisms. This disturbance leads to a reduction in microbial diversity, altered metabolite production, and compromised immune responses, resulting in a state referred to as dysbiosis. Broad-spectrum antibiotics tend to induce more severe dysbiosis compared to narrow-spectrum agents. Antibiotic-induced dysbiosis has been linked to the onset and progression of these disorders, emphasizing the far-reaching consequences of microbial imbalance. The review highlights various strategies to mitigate the adverse effects of antibiotics on gut health, like probiotics, fecal microbiota transplantation (FMT), and phage therapy, as promising approaches to restore and maintain a balanced gut microbiota. How to cite this article: Ramakrishna BS, Patankar R. Antibiotic-associated Gut Dysbiosis. J Assoc Physicians India 2023;71(11):62-68.

The usage of Gellhorn pessary in pelvic organ prolapse and in regards to success, continuity of use and effect on symptoms: a retrospective study of 2 years.

INTRODUCTION: Pelvic organ prolapse (POP) is a condition involving weakened pelvic floor muscles causing organs to protrude. Conservative POP treatment comprises pelvic floor exercises and vaginal pessaries. Besides conservative care, surgery is offered. However, surgery is invasive, risky and unsuitable for those with serious medical conditions. This study aims to assess the acceptance, success and outcomes of the Gellhorn pessary for POP treatment, especially in advanced cases. MATERIALS AND METHODS: The present study is a retrospective cohort study using hospital medical records (patient files) from October 2019 to November 2021 (for 2 years). This study was performed in Malaysian women (n=53) suffering from advanced stages of POP, in which Gellhorn pessaries of diameter (44-76mm) were inserted by trained personnel. Pelvic Floor Distress Inventory-20 (PFDI-20) and Pelvic Floor Impact Questionnaire-7 (PFIQ-7) were used to measure patients' symptoms and quality of life before and after Gellhorn pessary fitting. Patients were reassessed every three months for two years and their satisfaction scores were recorded. RESULTS: We observed a significant difference in pre-test (pre-fitting) and post-test (three months post-fitting) scores on all three subscales and the PFIQ-7 total score. Twentyeight (52.83%) patients continued the use of Gellhorn pessary for at least 24 months, whereas 25 (47.20%) patients discontinued during this period. A retrospective analysis of the patients who discontinued Gellhorn pessary showed that 13 (24.52%) patients gave up the use of pessary for definitive surgery. It is noteworthy to mention here that only one out of the 13 patients who were awaiting surgery, chose surgery and the remaining 12 changed their mind after being fitted with the Gellhorn pessary. Seven (13.20%) patients declined reinsertion due to discomfort and voiding difficulties and refused further intervention, whereas three (5.66%) patients requested a ring pessary. Two (3.77%) patients, requested the removal of pessary due to vesicovaginal fistula and rectovaginal fistula (caused by an impacted pessary). The rate of continued use was 79.24% (42 patients) after 1st year and 52.83% (28 patients) at the end of two years. CONCLUSION: In the current study, the Gellhorn pessary was used to treat stage 3 and 4 POP with significant symptom reduction post-fitting. More than half of the patients continued to use the pessary after 24 months of fitting. Therefore, the Gellhorn pessary can be used as a treatment strategy for stage 3 and 4 POP with reasonable acceptance in the Malaysian population.

Nitrite and Nitric Oxide Interconversion at Mononuclear Copper(II): Insight into the Role of the Red Copper Site in Denitrification.

Nitrite (NO2 - ) and nitric oxide (NO) interconversion is crucial for maintaining optimum NO flux in mammalian physiology. Herein we demonstrate that [L2 CuII (nitrite)]+ moieties (in 2 a and 2 b; where, L = Me2 PzPy and Me2 PzQu) with distorted octahedral geometry undergo facile reduction to provide tetrahedral [L2 CuI ]+ (in 3 a and 3 b) and NO in the presence of biologically relevant reductants, such as 4-methoxy-2,6-di-tert-butylphenol (4-MeO-2,6-DTBP, a tyrosine model) and N-benzyl-1,4-dihydronicotinamide (BNAH, a NAD(P)H model). Interestingly, the reaction of excess NO gas with [L2 CuII (MeCN)2 ]2+ (in 1 a) provides a putative {CuNO}10 species, which is effective in mediating the nitrosation of various nucleophiles, such as thiol and amine. Generation of the transient {CuNO}10 species in wet acetonitrile leads to NO2 - as assessed by Griess assay and 14 N/15 N-FTIR analyses. A detailed study reveals that the bidirectional NOx -reactivity, namely, nitrite reductase (NIR) and NO oxidase (NOO), at a common CuII site, is governed by the geometric-preference-driven facile CuII /CuI redox process. Of broader interest, this study not only highlights potential strategies for the design of copper-based catalysts for nitrite reduction, but also strengthens the previous postulates regarding the involvement of red copper proteins in denitrification.

3D visualization of perianal fistulas using parametric models.

BACKGROUND: Magnetic resonance imaging (MRI) is used as a standard for assessment of complex perianal fistulas. Apart from textual description of the case, 3D reconstructed models from MRI further aid in understanding the entire anatomy of the fistula tract and its relation to the pelvic floor. This information is crucial as it helps surgeons to understand the extent and complexity of the disease before surgical treatment. However, 3D model generation from MRI is a time-consuming step for a radiologist as it requires tedious manual delineations to be performed on every slice of the images. The aim of this study was to develop a method that could enable radiologists to present enhanced information to surgeons for treatment of complex perianal fistulas while simultaneously reducing the manual efforts and time required to generate the information. METHODS: A method was proposed to depict relevant anatomies of complex perianal fistula as parametric models in three-dimensional (3D) space. A plugin inside 3D Slicer software was developed for the generation of the parametric models from MRI. The levator ani muscle, internal sphincter, and external sphincter are represented as tubular structures, whereas fistula tracks and abscess are presented as splines. RESULTS: Parametric models were generated to depict three cases of complex perianal fistulas and similarity measures were computed for ten cases. Visual comparison of the parametric models was made with the 3D models generated by the standard approach. The parametric models took less time to create and were able to visually present enriched information as compared to the 3D models generated by the standard approach. CONCLUSIONS: The proposed method, using parametric models, shows potential for faster generation and better visualization of the 3D information required for the treatment of complex perianal fistula cases.

Assessment of small intestinal bacterial overgrowth in chronic pancreatitis patients using jejunal aspirate culture and glucose hydrogen breath test.

BACKGROUND: A subset of chronic pancreatitis patients respond poorly to pancreatic enzyme replacement therapy. Small intestinal bacterial overgrowth (SIBO) is considered to be one of the major reasons for this poor response. Previous studies have reported a wide range of prevalence of SIBO in patients with chronic pancreatitis. We aimed to assess the prevalence of SIBO in chronic pancreatitis using quantitative jejunal aspirate culture and glucose hydrogen breath test (GHBT). The sensitivity and specificity of GHBT for the diagnosis of SIBO in chronic pancreatitis were also estimated. METHODS: Newly diagnosed chronic pancreatitis patients were recruited into the study. A detailed history and relevant laboratory tests were done. All patients underwent an endoscopy and jejunal fluid aspiration for bacterial cultures and GHBT to detect SIBO. The results of GHBT were compared with jejunal fluid aspirate culture. RESULTS: The jejunal aspirate culture was positive in 18/48 (37.5%) patients while the GHBT showed that 14/48 (29%) patients had SIBO. The sensitivity, specificity, positive and negative predictive value of GHBT in our study was 44.4, 80, 57.14 and 70.59%, respectively. CONCLUSIONS: SIBO is not uncommon in chronic pancreatitis patients. One-third of our study population had SIBO. GHBT has low sensitivity but had high specificity in the diagnosis of SIBO in chronic pancreatitis.

Safety of hydroxychloroquine in healthcare workers for COVID-19 prophylaxis.

BACKGROUND & OBJECTIVES: Hydroxychloroquine (HCQ), reported to inhibit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication in in vitro studies, has been recommended for prophylaxis of COVID-19 in healthcare workers (HCWs). The objective of this study was to assess short-term adverse events (AEs) of HCQ in HCWs. METHODS: This cross-sectional study among consenting HCWs taking prophylaxis and working in hospitals with COVID-19 patients used online forms to collect details of HCWs, comorbidities, prophylactic drugs used and AEs after the first dose of HCQ. Verification of dose and AEs was done by personal contact. Multivariate logistic regression analysis was done to determine the effect of age, gender and dose of HCQ on AE. RESULTS: Of the 1303 HCWs included, 98.4 per cent (n=1282) took HCQ and 66 per cent (n=861) took 800 mg as first day's dose. Among the 19.9 per cent (n=259) reporting AEs, 1.5 per cent (n=20) took treatment for AE, none were hospitalized and three discontinued HCQ. Gastrointestinal AEs were the most common (172, 13.2%), with less in older [odds ratio (OR) 0.56, 95% confidence interval (CI) 0.35-0.89], with more in females (OR 2.46, 95% CI 1.78-3.38) and in those taking a total dose of 800 mg on day one compared to a lower dose. Hypoglycaemia (1.1%, n=14), cardiovascular events (0.7%, n=9) and other AEs were minimal. INTERPRETATION & CONCLUSIONS: HCQ prophylaxis first dose was well tolerated among HCWs as evidenced by a low discontinuation. For adverse effects, a small number required treatment, and none required hospitalization. The study had limitations of convenience sampling and lack of laboratory and electrocardiography confirmation of AEs.

Metal-free Transformations of Nitrogen-Oxyanions to Ammonia via Oxoammonium Salt.

Transformations of nitrogen-oxyanions (NOx- ) to ammonia impart pivotal roles in sustainable biogeochemical processes. While metal-mediated reductions of NOx- are relatively well known, this report illustrates proton-assisted transformations of NOx- anions in the presence of electron-rich aromatics such as 1,3,5-trimethoxybenzene (TMB-H, 1 a) leading to the formation of diaryl oxoammonium salt [(TMB)2 N+ =O][NO3- ] (2 a) via the intermediacy of nitrosonium cation (NO+ ). Detailed characterizations including UV/Vis, multinuclear NMR, FT-IR, HRMS, X-ray analyses on a set of closely related metastable diaryl oxoammonium [Ar2 N+ =O] species disclose unambiguous structural and spectroscopic signatures. Oxoammonium salt 2 a exhibits 2 e- oxidative reactivity in the presence of oxidizable substrates such as benzylamine, thiol, and ferrocene. Intriguingly, reaction of 2 a with water affords ammonia. Perhaps of broader significance, this work reveals a new metal-free route germane to the conversion of NOx  to NH3 .

Application of Quantum-Markov Open System Models to Human Cognition and Decision.

Markov processes, such as random walk models, have been successfully used by cognitive and neural scientists to model human choice behavior and decision time for over 50 years. Recently, quantum walk models have been introduced as an alternative way to model the dynamics of human choice and confidence across time. Empirical evidence points to the need for both types of processes, and open system models provide a way to incorporate them both into a single process. However, some of the constraints required by open system models present challenges for achieving this goal. The purpose of this article is to address these challenges and formulate open system models that have good potential to make important advancements in cognitive science.

Solid-State Hydrogen-Deuterium Exchange Mass Spectrometry: Correlation of Deuterium Uptake and Long-Term Stability of Lyophilized Monoclonal Antibody Formulations.

Solid state hydrogen-deuterium exchange with mass spectrometric analysis (ssHDX-MS) has been used to assess protein conformation and matrix interactions in lyophilized solids. ssHDX-MS metrics have been previously correlated to the formation of aggregates of lyophilized myoglobin on storage. Here, ssHDX-MS was applied to lyophilized monoclonal antibody (mAb) formulations and correlated to their long-term stability. After exposing lyophilized samples to D2O(g), the amount of deuterium incorporated at various time points was determined by mass spectrometry for four different lyophilized mAb formulations. Hydrogen-deuterium exchange data were then correlated with mAb aggregation and chemical degradation, which was obtained in stability studies of >2.5 years. Deuterium uptake on ssHDX-MS of four lyophilized mAb formulations determined at the initial time point prior to storage in the dry state was directly and strongly correlated with the extent of aggregation and chemical degradation during storage. Other measures of physical and chemical properties of the solids were weakly or poorly correlated with stability. The data demonstrate, for the first time, that ssHDX-MS results are highly correlated with the stability of lyophilized mAb formulations. The findings thus suggest that ssHDX-MS can be used as an early read-out of differences in long-term stability between formulations helping to accelerate formulation screening and selection.

Vitamin D status in Kancheepuram District, Tamil Nadu, India.

BACKGROUND: Vitamin D has multifarious roles in maintenance of health and prevention of disease. The present study was undertaken to assess the vitamin D status of a rural adult south Indian population and to identify its associations with socioeconomic status and cultural practices. METHODS: Between June 2015 and July 2016, 424 healthy adults residing in Kattankulathur block in Tamil Nadu, India, provided venous blood samples and answered questions by personal interview. 25-hydroxy vitamin D was estimated by ELISA. RESULTS: Fifty nine (13.9%) of the 424 participants had 25OHD levels below 12 ng/mL (vitamin D deficient) and 175 (41.3%) had 25OHD levels between 12 to 20 ng/mL (vitamin D insufficiency). In univariate analysis, demographic factors associated with vitamin D status included education, occupation, socioeconomic class, and birthplace; lifestyle factors included sun exposure time, skin surface exposed to sunlight, use of sunscreen, awareness of vitamin D, and consumption of fish; and hygiene related factors included source of drinking water, availability of tap water at home, and closed toilet at home. In ordinal logistic regression, the following variables were found to be independently associated with vitamin D sufficiency: Duration of daily sun exposure below 30 min (Odds ratio 0.31, 95% confidence intervals 0.14-0.71, P = 0.006), sun exposure 30-60 min (OR 0.49, 95% CI 0.30-0.80, P = 0.004), male gender (OR 2.00, 95% CI 1.30-3.09, P = 0.002), higher level of education (OR 0.80, 95% CI 0.69-0.94, P = 0.005), non-consumption of fatty fish (OR 0.48, 95% CI 0.24-0.85, P = 0.035) and presence of closed toilet system at home (OR 0.59, 95% CI 0.37-0.93). CONCLUSION: VDD and VDI are highly prevalent in this rural Indian community. The study identifies socioeconomic and behavior patterns that negatively impact vitamin D sufficiency, thus providing a basis for targeted intervention.

Variation in expression and activity pattern of mmp2 and mmp9 on different time scales in the regenerating caudal fin of Poecilia latipinna.

Alteration in the expression pattern of matrix metalloproteinase (MMP)2 and MMP9 was studied in the regenerating caudal fin of Poecilia latipinna immediately following amputation until the new tissues gained structural integrity. Timed expression pattern of these two MMPs was studied at enzyme, transcript as well as protein levels. Additionally, both the gelatinases were localized in the regenerating caudal fin during three specific stages of regeneration. The results revealed a progressive increase in the expression of MMP2 starting at 1 h post amputation (hpa), indicating its possible role in the remodelling of extracellular matrix early on during caudal-fin regeneration. Nevertheless, a reduction in transcript level expression of MMP2 at 6 hpa and 12 hpa stages, points towards a possible transcriptional regulation, to further moderate its activity. As observed in the case of MMP2, expression of MMP9 too increased from 1 hpa and remained elevated until 5 dpa. However, the active MMP9 revealed its presence only 12 hpa onwards. Moreover, both the gelatinases were localised in the apical epithelial cap and in the progress zone at wound epithelium (1 dpa) and blastema (60 hpa) stages respectively. Further, during early differentiation stage (5 dpa), high intensities of MMP2 and MMP9 were localized in the newly formed actinotrichia as compared with the tissue proximal to it. Based on the results, it could be construed that the controlled up-regulation of MMP2 and MMP9 from 1 hpa until the early differentiation stage ensures a regulated digestion of extracellular matrix, perhaps to facilitate the recruitment, proliferation, morphogenesis and re-patterning of resident stem cells during caudal fin regeneration in P. latipinna.

Faecal microbiota of healthy adults in south India: Comparison of a tribal & a rural population.

BACKGROUND & OBJECTIVES: The relevance of the gut microbiota to human health is increasingly appreciated. The objective of this study was to compare the gut microbiota of a group of adult tribals with that of healthy adult villagers in Tamil Nadu, India. METHODS: Faeces were collected from 10 healthy tribal adults (TAs) in the Jawadhi hills and from 10 healthy villagers [rural adults (RAs)] in Vellore district, Tamil Nadu. DNA was extracted, and 456 bp segments comprising hypervariable regions 3 and 4 of the 16S rRNA gene were amplified, barcoded and 454 sequenced. RESULTS: Totally 227,710 good-quality reads were analyzed. TAs consumed a millets-based diet, ate pork every day, and did not consume milk or milk products. RAs consumed a rice-based diet with meat intake once a week. In both groups, Firmicutes was the most abundant phylum, followed by Proteobacteria, Bacteroidetes and Actinobacteria. The median Firmicutes-to-Bacteroidetes ratio was 34.0 in TA and 92.9 in RA groups. Actinobacteria were significantly low in TA, possibly due to non-consumption of milk. Clostridium constituted the most abundant genus in both groups, but was significantly more abundant in TAs than RAs, while Streptococcus was significantly more abundant in RA (P<0.05). Analyses of genetic distance revealed that the microbiota were distinctly different between TA and RA, and principal component analysis using 550 distinct taxonomically identifiable sequences revealed a clear separation of microbiota composition in the two groups. Phylogenetic analysis of major microbiota indicated clustering of microbial groups at different major branch points for TAs and RAs. INTERPRETATION & CONCLUSIONS: Phylum Firmicutes and genus Clostridium constituted the bulk of the faecal microbiota, while significant differences in composition between the groups were probably due to differences in diet and lifestyle.

-1 V bias 67 GHz bandwidth Si-contacted germanium waveguide p-i-n photodetector for optical links at 56 Gbps and beyond.

We demonstrate a 67 GHz bandwidth silicon-contacted germanium waveguide p-i-n photodetector operating at -1 V with 6.8 fF capacitance. The dark current is below 4 nA. The responsivity is 0.74 A/W at 1550 nm and 0.93 A/W at 1310 nm wavelength. 56 Gbps on-off-keying data reception is demonstrated with clear open eye diagrams in both the C-band and O-band.

Thiol-Disulfide Exchange in Human Growth Hormone.

PURPOSE: Thiol-disulfide exchange was monitored in recombinant human growth hormone (hGH) and in model tryptic peptides derived from hGH to investigate the effects of higher-order structure on the reaction. METHODS: Different free thiol-containing peptides, varying in length and amino acid sequence, were used to initiate the reaction at pH 7.0 and 37°C in hGH. Protein samples were digested with trypsin and analyzed for native disulfides, scrambled disulfides and free thiols using LC/MS. The loss of native disulfide and disulfide exchange was compared with model peptides derived from hGH. RESULTS: Loss of native disulfide in cyclic (cT20-T21) and linear peptides (T20-T21pep) derived from the C-terminal hGH disulfide during the first 60 min of reaction was greater than loss of the C-terminal disulfide in hGH itself. Of the thiols tested, glutathione (GSH) was the most reactive, forming the highest percentage of mixed disulfides in intact hGH and in the model peptides. At longer reaction times (>240 min), native disulfides in both hGH and cT20-T21 were regenerated. The fastest rates of regeneration were observed for Cys and the di- or tripeptide containing an Arg residue adjacent to Cys, suggesting that they may be useful in refolding. CONCLUSIONS: Thiol-disulfide exchange reactions in hGH and related model peptides were influenced by higher order structure, by the size of the thiol reactant and by an Arg residue adjacent to Cys in the thiol reactant. Reduction of disulfide bonds in hGH did not affect higher order structure as measured by CD and HDX-MS.

Gram-negative infection as an unusual cause of endocarditis in a hemodialysis patient.

Gram-negative endocarditis is rare and it has high mortality if there is a delay in diagnosis and treatment. Gram-negative organisms should be considered in the differential diagnosis of IE in hemodialysis patients. Central lineassociated bloodstream infections (CLABSIs) can be prevented by following sterile measures during catheter insertion and proper management of catheter site.

Structural transitions and interactions in the early stages of human glucagon amyloid fibrillation.

A mechanistic understanding of the intermolecular interactions and structural changes during fibrillation is crucial for the design of safe and efficacious glucagon formulations. Amide hydrogen/deuterium exchange with mass spectrometric analysis was used to identify the interactions and amino acids involved in the initial stages of glucagon fibril formation at acidic pH. Kinetic measurements from intrinsic and thioflavin T fluorescence showed sigmoidal behavior. Secondary structural measurement of fibrillating glucagon using far-UV circular dichroism spectroscopy showed changes in structure from random coil → α-helix → ß-sheet, with increase in α-helix content during the lag phase followed by increase in ß-sheet content during the growth phase. Hydrogen/deuterium exchange with mass spectrometric analysis of fibrillating glucagon suggested that C-terminal residues 22-29 are involved in interactions during the lag phase, during which N-terminal residues 1-6 showed no changes. Molecular dynamics simulations of glucagon fragments showed C-terminal to C-terminal interactions with greater α-helix content for the 20-29 fragment, with hydrophobic and aromatic residues (Phe-22, Trp-25, Val-23, and Met-27) predominantly involved. Overall, the study shows that glucagon interactions during the early phase of fibrillation are mediated through C-terminal residues, which facilitate the formation of α-helix-rich oligomers, which further undergo structural rearrangement and elongation to form ß-sheet-rich mature fibrils.

Intermittent Directly Observed Therapy for Abdominal Tuberculosis: A Multicenter Randomized Controlled Trial Comparing 6 Months Versus 9 Months of Therapy.

BACKGROUND: The duration of treatment of gastrointestinal tuberculosis continues to be a matter of debate. The World Health Organization advocates intermittent directly observed short-course therapy (DOTs), but there is a lack of data of its efficacy in abdominal tuberculosis. We therefore conducted a multicenter randomized controlled trial to compare 6 months and 9 months of antituberculosis therapy using DOTs. METHODS: One hundred ninety-seven patients with abdominal tuberculosis (gastrointestinal, 154; peritoneal, 40; mixed, 3) were randomized to receive 6 months (n = 104) or 9 months (n = 93) of antituberculosis therapy using intermittent directly observed therapy. Patients were followed up 1 year after completion of treatment to assess recurrence. Patients were evaluated for primary endpoint (complete clinical response, partial response, and no response) and secondary endpoint (recurrence of the disease at the end of 1 year of follow-up). RESULTS: Baseline characteristics were similar between the 2 randomized groups. There was no difference between the 6-month group and 9-month group in the complete clinical response rate on per-protocol analysis (91.5% vs 90.8%; P = .88) or intent-to-treat analysis (75% vs 75.8%; P = .89). Only 1 patient in the 9-month group and no patients in the 6-month group had recurrence of disease. Side effects occurred in 21 (21.3%) and 16 (18.2%) patients in the 6-month and 9-month groups, respectively. CONCLUSIONS: There was no difference in efficacy of antituberculosis therapy delivered for either 6 months or 9 months in either gastrointestinal or peritoneal tuberculosis, confirming the efficacy of intermittent directly observed therapy. CLINICAL TRIALS REGISTRATION: NCT01124929.

Photolytic Cross-Linking to Probe Protein-Protein and Protein-Matrix Interactions in Lyophilized Powders.

Protein structure and local environment in lyophilized formulations were probed using high-resolution solid-state photolytic cross-linking with mass spectrometric analysis (ssPC-MS). In order to characterize structure and microenvironment, protein-protein, protein-excipient, and protein-water interactions in lyophilized powders were identified. Myoglobin (Mb) was derivatized in solution with the heterobifunctional probe succinimidyl 4,4'-azipentanoate (SDA) and the structural integrity of the labeled protein (Mb-SDA) confirmed using CD spectroscopy and liquid chromatography/mass spectrometry (LC-MS). Mb-SDA was then formulated with and without excipients (raffinose, guanidine hydrochloride (Gdn HCl)) and lyophilized. The freeze-dried powder was irradiated with ultraviolet light at 365 nm for 30 min to produce cross-linked adducts that were analyzed at the intact protein level and after trypsin digestion. SDA-labeling produced Mb carrying up to five labels, as detected by LC-MS. Following lyophilization and irradiation, cross-linked peptide-peptide, peptide-water, and peptide-raffinose adducts were detected. The exposure of Mb side chains to the matrix was quantified based on the number of different peptide-peptide, peptide-water, and peptide-excipient adducts detected. In the absence of excipients, peptide-peptide adducts involving the CD, DE, and EF loops and helix H were common. In the raffinose formulation, peptide-peptide adducts were more distributed throughout the molecule. The Gdn HCl formulation showed more protein-protein and protein-water adducts than the other formulations, consistent with protein unfolding and increased matrix interactions. The results demonstrate that ssPC-MS can be used to distinguish excipient effects and characterize the local protein environment in lyophilized formulations with high resolution.