pH responsive cylindrical MSN for oral delivery of insulin-design,fabrication and evaluation

Objective: The objective of the present study was to develop novel PMV [poly (methacrylic acid-co-vinyl triethoxylsilane)]-coated mesoporous silica nanoparticles (MSN) with improved hypoglycemic effect for oral insulin (INS) delivery.

Methods: MSN was synthesized under acidic condition using Pluronic® P 123 and Tetra ethoxy orthosilane. Surfactant was removed by calcination. Calcined MSN was coated with pH sensitive polymer PMV. Cytotoxicity of this coated MSN was evaluated by MTT assay using CHO-K1 cell line. Different MSN samples were characterized with BET surface area analyzer, FESEM, TEM, FT-IR, XRD, TG-DTA. In vivo study was performed using male rats. Pharmacokinetic study was conducted using HPLC.

Results and discussion: Highest surface area (304.3921 m²/g) was observed in case of calcined sample. Adsorption pore width of final coated sample was highest (64.7844?nm) compared with others. No noticeable cytotoxicity was observed for this coated support. The entrapment efficiency of insulin was found to be 39.39%. In vitro studies were done at different pH using Franz-diffusion cell. Results showed significant release at pH 7.4. Cumulative drug release over a period of 6?h was more than 48% at this systemic pH. Effect of this MSN-PMV-INS on blood glucose level was retained for 16?h. This novel formulation has shown 73.10% relative bioavailability of insulin.

Conclusion: A novel-coated mesoporous silica support was successfully developed for delivery of insulin through oral route.     

Gallbladder adenomyomatosis with tubercular portal lymphadenopathy masquerading as gallbladder carcinoma

Gallbladder carcinoma is more likely to occur in elderly females and the presence of periportal adenopathy often signifies advanced disease. Such patients are generally not taken up for surgery and are treated palliatively. Isolated periportal tuberculosis without the evidence of disease elsewhere is in itself a rarity. Here we present a case study of gallbladder mass suspected of being gallbladder carcinoma with portal lymphatic metastasis actually turning out to be that of gallbladder adenomyoma with periportal tuberculosis. This case illustrates how mass lesions of the gallbladder are commonly and falsely interpreted to be malignant.     

Establishment of age-specified bone mineral density reference range for Indian females using dual-energy X-ray absorptiometry

We undertook this study to establish age-specified bone mineral density (BMD) reference range for Indian females using dual-energy X-ray absorptiometry. BMD at multiple skeletal sites was measured in 2034 healthy women aged 18--85yr. The effect of anthropometry and biochemical parameters on BMD was determined. Peak BMD was observed between 30 and 35yr at the hip, lumbar spine, and radius. Significant positive correlation of height and weight with BMD was observed at 33% radius, femur neck, and lumbar spine, whereas significant negative correlation was seen between serum alkaline phosphatase (ALP) and serum parathyroid hormone levels with BMD at aforementioned sites. On multivariate regression analysis, age, weight, and serum ALP were the most consistent contributors to variance in the BMD. Compared with age-matched US females, BMD of lumbar spine was significantly lower for our subjects in all age groups. Prevalence of osteoporosis among women aged older than 50yr was significantly higher based on Caucasian T-scores as opposed to using peak BMD/standard deviation values from the population under review at lumbar spine but not at femoral neck.     

Framework for a National STEMI Program: Consensus document developed by STEMI INDIA,Cardiological Society of India and Association Physicians of India

The health care burden of ST elevation myocardial infarction (STEMI) in India is enormous. Yet, many patients with STEMI can seldom avail timely and evidence based reperfusion treatments. This gap in care is a result of financial barriers, limited healthcare infrastructure, poor knowledge and accessibility of acute medical services for a majority of the population. Addressing some of these issues, STEMI India, a not-for-profit organization, Cardiological Society of India (CSI) and Association Physicians of India (API) have developed a protocol of “systems of care” for efficient management of STEMI, with integrated networks of facilities. Leveraging newly-developed ambulance and emergency medical services, incorporating recent state insurance schemes for vulnerable populations to broaden access, and combining innovative, “state-of-the-art” information technology platforms with existing hospital infrastructure, are the crucial aspects of this system. A pilot program was successfully employed in the state of Tamilnadu. The purpose of this article is to describe the framework and methods associated with this programme with an aim to improve delivery of reperfusion therapy for STEMI in India. This programme can serve as model STEMI systems of care for other low-and-middle income countries.     

Whole-genome RNAi screen highlights components of the endoplasmic reticulum/Golgi as a source of resistance to immunotoxin-mediated cytotoxicity

Immunotoxins (antibody–toxin fusion proteins) target surface antigens on cancer cells and kill these cells via toxin-mediated inhibition of protein synthesis. To identify genes controlling this process, an RNAi whole-genome screen (∼22,000 genes at three siRNAs per gene) was conducted via monitoring the cytotoxicity of the mesothelin-directed immunotoxin SS1P. SS1P, a Pseudomonas exotoxin-based immunotoxin, was chosen because it is now in clinical trials and has produced objective tumor regressions in patients. High and low concentrations of SS1P were chosen to allow for the identification of both mitigators and sensitizers. As expected, silencing known essential genes in the immunotoxin pathway, such as mesothelin, furin, KDEL receptor 2, or members of the diphthamide pathway, protected cells. Of greater interest was the observation that many RNAi targets increased immunotoxin sensitivity, indicating that these gene products normally contribute to inefficiencies in the killing pathway. Of the top sensitizers, many genes encode proteins that locate to either the endoplasmic reticulum (ER) or Golgi and are annotated as part of the secretory system. Genes related to the ER-associated degradation system were not among high-ranking mitigator or sensitizer candidates. However, the p97 inhibitor eeyarestatin 1 enhanced immunotoxin killing. Our results highlight potential targets for chemical intervention that could increase immunotoxin killing of cancer cells and enhance our understanding of toxin trafficking.Antibody-based cancer therapeutics are designed to kill target cells, ideally causing little damage to normal cells. These molecules extend from intact IgG molecules through antibody–drug conjugates to antibody–toxin fusions (1–4). When antibodies are tasked with delivering radionuclides or T cells, surface binding is usually sufficient. However, when delivering toxic payloads, antibody internalization to specific intracellular pathways plays a critical role in determining cellular susceptibility (5–8).Immunotoxin design includes an antibody fragment, either Fv or Fab, fused with a protein toxin (4, 9–11). The antibody fragment binds a surface antigen leading to internalization followed by cleavage via the cellular protease, furin, which begins separating the toxin from the antibody Fv (12, 13). Separation is completed by a reduction step that generates a C-terminal toxin fragment of 35 kDa (14). This fragment contains a KDEL-like sequence at the C terminus, which is necessary for cell killing (15). The need for a KDEL-like sequence implicates the endoplasmic reticulum (ER) as an essential organelle in the toxin pathway and suggests that the toxin travels to the ER via a retrograde pathway. KDEL-receptor 2 (KDELR2) has been shown to interact with Pseudomonas exotoxin (PE)-derived immunotoxins (16). From the ER, the C-terminal toxin fragment translocates to the cell cytosol, where it ADP-ribosylates elongation factor 2 (EF2). Only EF2 that is modified posttranslationally by a multistep diphthamide pathway is susceptible to toxin-mediated ADP ribosylation (17–20). Cells succumb because ADP-ribosylated EF2 no longer functions at the elongation step of protein translation. Death results from a combination of events: the loss of short-lived survival proteins (e.g., Mcl1), triggering apoptosis, and stress responses that cannot be executed because protein translation is shut down (21). Regarding the constituents of the pathway responsible for transporting the immunotoxin from the surface to the cytosol, there are only a handful of experimentally established components. These proteins include the surface target itself, the protease furin, and KDELR2 (discussed below). In addition, within the cytosol, the diphthamide pathway responsible for the multistep posttranslational modification of EF2, converting histidine 715 to diphthamide, is necessary (22, 23). Beyond these components, the total number of constituents is unknown, although it is under study (24). Silencing of genes associated with the immunotoxin pathway would likely change cell sensitivity. Furthermore, should these gene products be amenable to regulation via small molecular drugs, alterations of killing activity might be possible via chemical intervention (25, 26).Mesothelin is expressed on mesotheliomas, as well as on other epithelial cancers (27–32). The immunotoxin SS1P was designed to kill cells displaying this surface protein and is currently under clinical evaluation. Of note, recent results from a phase 1 trial combining SS1P with pemetrexed and cisplatin reported a 60% response rate in patients with pleural mesothelioma and a 77% response rate at the maximum tolerated dose (33). Mesothelin is expressed on KB cells at about 10,000 copies per cell, rendering these cells moderately sensitive to the SS1P immunotoxin with an IC₅₀ of 10–20 ng/mL.RNAi results in the loss of mRNA from target genes (34). To identify genes involved in immunotoxin-mediated killing, we undertook a whole-genome screen where three siRNAs per gene were added before the addition of a high or low concentration of immunotoxin. Genes were scored as “mitigators” or “sensitizers” based on their protection from or enhancement of immunotoxin action. To validate selected targets, additional siRNAs were tested via dose–response analysis of immunotoxin action. Here, we confirm the roles of essential genes in the immunotoxin pathway and identify previously unknown members of the toxin pathway, notably those members that usually protect cells from immunotoxin action but, when reduced in expression, lead to the sensitization of cells.