Cellular adhesion and chondrogenic differentiation inside an alginate-based bioink in response to tailorable artificial matrices and tannic acid treatment

Many established bioinks fulfill important requirements regarding fabrication standards and cytocompatibility. Current research focuses on development of functionalized bioinks with an improved support of tissue-specific cell differentiation. Many approaches primarily depend on decellularized extracellular matrices or blood components. In this study, we investigated the combination of a highly viscous alginate-methylcellulose (algMC) bioink with collagen-based artificial extracellular matrix (aECM) as a finely controllable and tailorable system composed of collagen type I (col) with and without chondroitin sulfate (CS) or sulfated hyaluronan (sHA). As an additional stabilizer, the polyphenol tannic acid (TA) was integrated into the inks. The assessment of rheological properties and printability as well as hydrogel microstructure revealed no adverse effect of the integrated components on the inks. Viability, adhesion, and proliferation of bioprinted immortalized human mesenchymal stem cells (hTERT-MSC) was improved indicating enhanced interaction with the designed microenvironment. Furthermore, chondrogenic matrix production (collagen type II and sulfated glycosaminoglycans) by primary human chondrocytes (hChon) was enhanced by aECM. Supplementing the inks with TA was required for these positive effects but caused cytotoxicity as soon as TA concentrations exceeded a certain amount. Thus, combining tailorable aECM with algMC and balanced TA addition proved to be a promising approach for promoting adhesion of immortalized stem cells and differentiation of chondrocytes in bioprinted scaffolds.

Extended septal myectomy using a combined trans-aortic and apical approach for long basal and mid-cavity hypertrophic cardiomyopathy

Surgical septal myectomy is the treatment of choice for patients of hypertrophic cardiomyopathy who are symptomatic despite maximal medical therapy. Residual obstruction results in the persistence of symptoms and poorer outcomes. The length (depth) of the septum excised as far towards the apex is important. A combined approach of trans-aortic and trans-apical is needed to achieve this in specific cases with associated mid-cavity obstruction. We present a case of a complex long-segment septal hypertrophy which underwent a successful septal reduction using a combined trans-aortic and trans-apical approach.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12055-022-01377-4.

Hardware Failure as a Rare Complication of Percutaneous Coronary Intervention: A Case Report

Percutaneous coronary intervention (PCI) is increasingly employed in the treatment of complex coronary artery disease. The entrapment or fracture of a coronary angioplasty guidewire is a rare complication of PCI. We herein describe a 61-year-old man who presented with chronic stable angina. The patient’s coronary angiogram revealed triple-vessel coronary artery disease, and he was scheduled for primary PCI. During the procedure, the guidewire fractured within the right coronary artery. Despite multiple attempts, the wire could not be retrieved. The wire unraveled in its coils, and its stretching resulted in its eventual snapping in the right radial artery. The initial plan was to attempt guidewire retrieval through a brachial cut-down, and if successful, to manage the obtuse marginal lesion by PCI, thereby precluding general anesthesia and a sternotomy. Unfortunately, the guidewire snapped at the brachial level, necessitating its retrieval by coronary artery bypass surgery. The patient remained asymptomatic and event-free over 6 months of follow-up.

An unusual cause of acute mitral regurgitation in TTK Chitra heart valve prosthesis

Structural failure of mechanical heart valve was a known feature when it was evolving in the 1960s and 1970s. With the advent of pyrolytic carbon and a better design, it is a rare entity with present valves. We report a case of disc fracture leading to acute mitral regurgitation in TTK Chitra heart valve prosthesis (CHVP) (TTK Healthcare Limited, India) heart valve, 6 years after its implantation in mitral position.

Incidence, prevalence, and mortality associated with head and neck cancer in India: Protocol for a systematic review

BACKGROUND

Head and neck cancer (HNC) is a heterogeneous tumor at various anatomic sites and one of the most common cancers in India. Published and existing reports and studies highlight an alarming increase in the incidence, prevalence, and mortality of HNC. Despite its high incidence, there is a dearth of more precise estimates of reliable epidemiological data pertaining to HNC in India.

AIM

This protocol aims to conduct a full-scale systematic review and meta-analysis on the HNC epidemiology (incidence, prevalence, and mortality) in 29 states and 7 union territories of India.

METHODS AND ANALYSIS

We will search for eligible published studies through PubMed, Scopus, Science Direct, MEDLINE, Web of Science, and Cochrane Review. Cancer registries such as (but not limited to) World Health Organization, International Agency for Research on Cancer, and the National Centre for Disease Informatics and Research-National Cancer Registry Program, which is maintained by the Indian Council of Medical Research, will be used for extracting relevant data using a standardized data collection form. The random-effects model of meta-analysis will be employed to aggregate the pooled estimates of relative ratios with 95% confidence intervals. Publication bias will be assessed using a funnel plot, and Egger's regression will be applied to test the symmetry of the funnel plot.

DISCUSSION

This review will provide updated evidence of the current burden of HNC in India. This will guide future studies and cancer registry reports to provide holistically representative epidemiological data.

SYSTEMATIC REVIEW REGISTRATION

In accordance with the guidelines, our systematic review protocol was registered with the International Prospective Register of Systematic Reviews and was assigned the registration number, CRD42017077482.

Chasing the umbrella: delayed migration of ductal occluder device into the aorta

Delayed migration of a ductal occluder device into the aorta after transcatheter closure of a patent ductus arteriosus is extremely rare. We present a case of delayed migration of a ductal occluder into the descending aorta 4 months after its deployment in an 11-year-old girl. Successful surgical removal of the device from the descending aorta and triple-ligation of the ductus arteriosus was performed via a left thoracotomy. The patient made an uneventful recovery.

Head and neck cancer risk factors in India: protocol for systematic review and meta-analysis

INTRODUCTION

Demographic, behavioural and environmental factors have been associated with increased risk of head and neck cancer (HNC). We will review published reports and explore connections between risk factors and HNC incidence. This protocol aims to provide strategies for a systematic review and meta-analysis of HNC risk factor analysis in India. It also provides guidelines in order to visualise obtained HNC risk factor data in the form of a heat-map highlighting variations across gender, age and geographical location.

METHODS AND ANALYSIS

We will identify well-established HNC risk factors and perform a comprehensive systematic review and meta-analysis to quantify each risk factor's impact on HNC incidence. A systematic search will be performed to identify the studies and published reports of HNC risk factors in India. Meta-analysis will be conducted to estimate the proportional contribution of the most prevalent risk factor in HNC on a city-wide basis in Indian states and territories.

ETHICS AND DISSEMINATION

The review protocol draws on publicly available anonymised data without directly involving human participants and therefore requires neither formal human ethical review nor approval by a human research ethics committee. We published an outline of the protocol in the International Prospective Register of Systematic Reviews (PROSPERO) in 2017. The results will provide an updated analysis of HNC risk factor prevalence in India, and we will discuss the applicability of rehabilitation care. We plan to disseminate the findings of this systematic review through publication in a peer-reviewed journal and presentation at relevant conference proceedings.

PROSPERO REGISTRATION NUMBER

CRD42017077758.

Role of the stability of charge ordering in exchange bias effect in doped manganites

In this work we have carried out an elaborate study on the magnetic properties and investigated the exchange bias phenomena of some charge-ordered (CO) manganites. The detailed study of Sm_1−xCa_xMnO₃ (x = 0.5, 0.55, 0.6, 0.65, 0.7) compounds shows that Sm_0.4Ca_0.6MnO₃, which is the most robust charge ordered material studied here, shows significantly large exchange bias field (H_E) as compared to the other compounds. Our experimental results and analysis indicate that T_CO, which reflects the stability of the charge-ordered state, is one of the key parameters for the exchange bias effect. Similar behaviour is found in other rare-earth analogues, viz., La_1−xCa_xMnO₃ and Pr_1−xCa_xMnO₃ compounds as well. We also found that with increasing stability of CO states in Sm_1−xCa_xMnO₃ compounds, H_E enhances due to increase in number and reduction in size of ferromagnetic clusters.

Paraneoplastic polymyositis presenting as a clinically occult breast cancer

Paraneoplastic syndrome affects less than 1% of cancer patients. Diagnosis of paraneoplastic syndrome with neurological presentation requires screening for an underlying malignancy, including a complete history, physical examination and imaging studies. Treatment often results in symptom stability, rather than improvement. Paraneoplastic polymyositis can precede or instantaneously occur at diagnosis or treatment of a primary tumour, while neurological symptoms can persist even following cancer treatment. We report a rare case of metaplastic breast carcinoma with an unusual presentation of paraneoplastic polymyositis.

Absence of low energy magnetic spin-fluctuations in isovalently and aliovalently doped LaCo2B2 superconducting compounds

Magnetization, resistivity and (11)B, (59)Co NMR measurements have been performed on the Pauli paramagnet [Formula: see text], and the superconductors [Formula: see text] ([Formula: see text] K) and [Formula: see text] ([Formula: see text] K). The site selective NMR experiment reveals the multiband nature of the Fermi surface in these systems. The temperature independent Knight shift and 1/T 1 T clearly indicate the absence of correlated low energy magnetic spin-fluctuations in the normal state, which is in contrast to other Fe-based pnictides. The density of states (DOS) of Co 3d electrons has been enhanced in superconducting [Formula: see text] and [Formula: see text] with respect to the non superconducting reference compound [Formula: see text]. The occurrence of superconductivity is related to the DOS enhancement.

Stable room temperature magnetic ordering and excellent catalytic activity of mechanically activated high surface area nanosized Ni0.45Zn0.55Fe2O4

Mechanosynthesized nanometric Ni_0.45Zn_0.55Fe₂O₄ exhibit stable magnetic ordering at room temperature, excellent catalytic property and memory effect in dc magnetization profile.

Brain-Targeted Nasal Clonazepam Microspheres

Gelatin-chitosan mucoadhesive microspheres of clonazepam were prepared using the emulsion cross linking method. Mirospheres were evaluated using the in vitro and ex vivo drug release patterns. In vivo CNS drug distribution studies were carried out in rats by administering the clonazepam microspheres intra-nasally and clonazepam solution intravenously. From the drug levels in plasma and CSF, drug targeting index and drug targeting efficiency were calculated. Results obtained indicated that intranasally administered clonazepam microspheres resulted in higher brain levels with a drug targeting index of 2.12. Gelatin-chitosan cross linked mucoadhesive microspheres have the potential to be developed as a brain-targeted drug delivery system for clonazepam.

Chaperone-like activity of tubulin. binding and reactivation of unfolded substrate enzymes

The eukaryotic cytoskeletal protein tubulin is a heterodimer of two subunits, alpha and beta, and is a building block unit of microtubules. In a previous communication we demonstrated that tubulin possesses chaperone-like activities by preventing the stress-induced aggregation of various proteins (Guha, S., Manna, T. K., Das, K. P., and Bhattacharyya, B. (1998) J. Biol. Chem. 273, 30077-30080). As an extension of this observation, we explored whether tubulin, like other known chaperones, also protected biological activity of proteins against thermal stress or increased the yields of active proteins during refolding from a denatured state. We show here that tubulin not only prevents the thermal aggregation of alcohol dehydrogenase and malic dehydrogenase but also protects them from loss of activity. We also show that tubulin prevents the aggregation of substrates during their refolding from a denatured state and forms a stable complex with denatured substrate. The activity of malic dehydrogenase, alpha-glucosidase, and lactate dehydrogenase during their refolding from urea or guanidium hydrochloride denatured states increased significantly in presence of tubulin compared with that without tubulin. These results suggest that tubulin, in addition to its role in mitosis, cell motility, and other cellular events, might be implicated in protein folding and protection from stress.

Role of the carboxy-termini of tubulin on its chaperone-like activity

Mutational analysis and the enzymatic digestion of many chaperones indicate the importance of both hydrophobic and hydrophilic residues for their unique property. Thus, the chaperone activity of alpha-crystallin is lost due to the substitution of hydrophobic residues or upon enzymatic digestion of the negatively charged residues. Tubulin, an eukaryotic cytoskeletal protein, exhibits chaperone-like activity as demonstrated by prevention of DTT-induced aggregation of insulin, thermal aggregation of alcohol dehydrogenase, betagamma-crystallin, and other proteins. We have shown that the tubulin lost its chaperone-like activity upon digestion of its negatively charged C-termini. In this article, the role of the C-terminus of individual subunits has been investigated. We observe that the digestion of C-terminus of beta-subunit with subtilisin causes loss of chaperone-like activity of tubulin. The contribution of C-terminus of alpha-subunit is difficult to establish directly as subtilisin cleaves C-terminus of beta-subunit first. This has been ascertained indirectly using a 14-residue peptide P2 having the sequence corresponding to a conserved region of MHC class I molecules and that binds tightly to the C-terminus of alpha-subunit. We have shown that the binding of P2 peptide to alphabeta-tubulin causes complete loss of its chaperone-like activity. NMR and gel-electrophoresis studies indicate that the P2 peptide has a significant higher binding affinity for the C-terminus of alpha-subunit compared to that of beta-subunit. Thus, we conclude that both the C-termini are necessary for the chaperone-like activity of tubulin. Implications for the chaperone functions in vivo have been discussed.

The spindle checkpoint of the yeast Saccharomyces cerevisiae requires kinetochore function and maps to the CBF3 domain

We have measured the activity of the spindle checkpoint in null mutants lacking kinetochore activity in the yeast Saccharomyces cerevisiae. We constructed deletion mutants for nonessential genes by one-step gene replacements. We constructed heterozygous deletions of one copy of essential genes in diploid cells and purified spores containing the deletion allele. In addition, we made gene fusions for three essential genes to target the encoded proteins for proteolysis (degron alleles). We determined that Ndc10p, Ctf13p, and Cep3p are required for checkpoint activity. In contrast, cells lacking Cbf1p, Ctf19p, Mcm21p, Slk19p, Cse4p, Mif2p, Mck1p, and Kar3p are checkpoint proficient. We conclude that the kinetochore plays a critical role in checkpoint signaling in S. cerevisiae. Spindle checkpoint activity maps to a discreet domain within the kinetochore and depends on the CBF3 protein complex.

The IML3/MCM19 gene of Saccharomyces cerevisiae is required for a kinetochore-related process during chromosome segregation

The mcm19 mutation in budding yeast affects minichromosome maintenance. In this work we have shown that this mutation leads to defects in the segregation of minichromosomes and chromosomes. The mutant cells show defective kinetochore function as judged by three criteria-- relaxation of the transcriptional block normally associated with a CEN box, stable maintenance of a dicentric plasmid in mutant cells, and mild sensitivity to the antimicrotubule drug benomyl. The MCM19 gene has been cloned and found to be the same as IML3, which codes for the ORF YBR107C. Deletion of the gene was not lethal, nor did it confer any growth defects on the mutant cells. However, the mcm19 null mutation conferred growth defects in the presence of a mutation in the TUB1 gene coding for alpha-tubulin. Two-hybrid experiments showed an interaction between Im13p/Mcm19p and the kinetochore protein Ch14, indicating that the Im13/Mcm19 protein has a role in kinetochore function.

MCM21 and MCM22, two novel genes of the yeast Saccharomyces cerevisiae are required for chromosome transmission

The minichromosome maintenance genes, MCM21 and MCM22, have been cloned and are shown to code for the ORFs YDR318W and YJR135C respectively. Mutations in these genes caused a decrease in the stability of the minichromosome. This decrease in stability was associated with an increase in the copy number of the minichromosome in cells carrying it. Small circular dicentric plasmids were maintained relatively stably and structurally intact in the mutants compared with the wild-type strain. In the latter, such plasmids were mitotically unstable and, upon recovery, showed frequent rearrangements of their DNA. A centromere offered less obstruction to transcription in mutant cells than in the wild type, showing that both these mutants had a more relaxed kinetochore assembly. The mutant strains showed elevated rates of chromosome loss but not those of recombination. Both the mutations caused the cells to display a higher sensitivity towards the anti-mitotic drug benomyl. All these observations suggest that MCM21 and MCM22 are important for chromosome segregation with a potential role in kinetochore function. These genes are non-essential, as their deletions from chromosomes did not cause loss of cell viability. However, exponentially growing mutant cells carrying the deletion of the MCM21 gene had a significant population of large-budded cells with a single nucleus at the neck. Furthermore, the DNA content of these cells showed a shift towards 2N, suggesting a temporary pause of cells in G2 or in an early phase of mitosis. The mcm21 and mcm22 mutations do not show synthetic lethality or any further enhancement of growth defects, implying that they could be carrying out non-overlapping functions in chromosome segregation.

Hematopoietic regulation mediated by interactions among the neurokinins and cytokines

This review summarizes the current data regarding the mechanisms by which two mammalian neurokinins (tachykinins), substance P (SP) and neurokinin-A (NK-A) are involved in hematopoiesis. SP and NK-A are derived from the preprotachykinin-I (PPT-I) gene which can be induced by cytokines and neurotrophic factors. In the bone marrow (BM), nerve fibers and stroma are potential sources for the PPT-I gene products. SP and NK-A interact with either of three cloned receptors, neurokinin-1 (NK-1), NK-2 or NK-3, although SP and NK-A exhibit binding preferences for NK-1 and NK-2 respectively. Through specific receptors, SP and NK-A exert dichotomous hematopoietic effects mediated mostly by the BM stroma. SP enhances the proliferation of primitive BM stem cells and progenitors and these effects correlate with the induction of stimulatory hematopoietic growth factors. NK-A appears to be protective to stem cells through the induction of TGF-beta. Proliferation of myeloid progenitors is inhibited by NK-A, effects which correlate with the induction of two suppressive factors, TGF-beta and MIP-1alpha. Stimulation of NK-2 leads to partial blunting of the enhanced stimulatory effects mediated by NK-1. Furthermore, stimulatory hematopoietic cytokines upregulate NK-1 expression and downregulate the constitutively expressed NK-2 in BM stroma. Together, the experimental evidence suggests that NK-A-NK-2 interactions could be a feedback to hematopoietic stimulation. Expression of NK-1 and NK-2 in CD34+ cell lines and also, the presence of SP binding sites on primary CD34+ cells suggest that the neurokinins could be interacting directly with BM progenitors and stem cells. In BM stroma, cytokines and neurokinins regulate the expression of each other and also, their respective receptors. In summary, the current literature pertaining to hematopoietic regulation indicates the involvement of a complex network that includes, but not exclusive of the cytokines and neurokinins. The current models that pertain to stem cell proliferation and differentiation should therefore add neuropeptides to the list of hematopoietic modulators.

The mcm17 mutation of yeast shows a size-dependent segregational defect of a mini-chromosome

Mini-chromosome-maintenance (mcm) mutants were described earlier as yeast mutants which could not stably maintain mini-chromosomes. Out of these, the ARS-specific class has been more extensively studied and is found to lose chromosomes and mini-chromosomes due to a defect in the initiation of DNA replication at yeast ARSs. In the present study we have identified a number of mcm mutants which show size-dependent loss of mini-chromosomes. When the size of the mini-chromosome was increased, from about 15 kb to about 60 kb, there was a dramatic increase in its mitotic stability in these mutants, but not in the ARS-specific class of mutants. One mutant, mcm17, belonging to the size-dependent class was further characterized. In this mutant, cells carried mini-chromosomes in significantly elevated copy numbers, suggesting a defect in segregation. This defect was largely suppressed in the 60-kb mini-chromosome. A non-centromeric plasmid, the TRP1ARS1 circle, was not affected in its maintenance. This mutant also displayed enhanced chromosome-III loss during mitosis over the wild-type strain, without elevating mitotic recombination. Cloning and sequencing of MCM17 has shown it to be the same as CHL4, a gene required for chromosome stability. This gene is non-essential for growth, as its disruption or deletion from the chromosome did not affect the growth-rate of cells at 23 degrees C or 37 degrees C. This work suggests that centromere-directed segregation of a chromosome in yeast is strongly influenced by its length.

Receptor induction regulates the synergistic effects of substance P with IL-1 and platelet-derived growth factor on the proliferation of bone marrow fibroblasts

The neuropeptide substance P (SP) stimulates CFU in bone marrow (BM) cultures. Although the methylcellulose matrix used in these assays does not provide an appropriate substratum to support adherent-dependent cells, we have observed that cultures containing optimal SP (10(-8)-10(-10) M) develop confluent areas of reticular/fibroblastoid-like cells with CFUs predominantly localized within their vicinity. Characterization (cytochemical and immunofluorescence) of the reticular/fibroblastoid-like cells indicated that they were fibroblasts, the major constituent of the BM stroma. Hemopoietic effects by SP are mediated by the stroma that expresses SP receptors. We studied the effects of SP (10(-7)-10(-11) M) with suboptimal platelet-derived growth factor-BB (PDGF-BB; 5 ng/ml) and IL-1alpha (2 ng/ml), two fibrogenic cytokines, and also hemopoietic regulators. SP by itself and in synergy with either cytokine induced fibroblast proliferation. At optimum SP, IL-1alpha induced 1.6 times the proliferation of PDGF-BB (87 +/- 7 vs 55 +/- 5; n = 12; p < 0.05). The effects of SP were blunted by a specific neurokinin-1 antagonist. Scatchard analysis indicated that SP binds to BM fibroblasts with an approximate Kd of 5 nM. SP induced steady state mRNA for IL-1 receptor IL-1RI and PDGF-BB (PDGF-AR, PDGF-BR) receptors by 7.5-, 6.2-, and 10.5-fold, respectively. Their up-regulation may be partly responsible for the synergistic effects of SP and their ligands. Induction (3-fold) of neurokinin-1 mRNA by IL-1alpha compared with no induction by PDGF-BB may explain the preferred synergism between SP and IL-1alpha. This study indicates that induction of SP, IL-1alpha, and PDGF-BB receptors is important to their synergistic effects on BM fibroblast proliferation. These results bring new insights into stroma-mediated hemopoietic regulation.

Receptor induction regulates the synergistic effects of substance P with IL-1 and platelet-derived growth factor on the proliferation of bone marrow fibroblasts

The neuropeptide substance P (SP) stimulates CFU in bone marrow (BM) cultures. Although the methylcellulose matrix used in these assays does not provide an appropriate substratum to support adherent-dependent cells, we have observed that cultures containing optimal SP (10(-8)-10(-10) M) develop confluent areas of reticular/fibroblastoid-like cells with CFUs predominantly localized within their vicinity. Characterization (cytochemical and immunofluorescence) of the reticular/fibroblastoid-like cells indicated that they were fibroblasts, the major constituent of the BM stroma. Hemopoietic effects by SP are mediated by the stroma that expresses SP receptors. We studied the effects of SP (10(-7)-10(-11) M) with suboptimal platelet-derived growth factor-BB (PDGF-BB; 5 ng/ml) and IL-1alpha (2 ng/ml), two fibrogenic cytokines, and also hemopoietic regulators. SP by itself and in synergy with either cytokine induced fibroblast proliferation. At optimum SP, IL-1alpha induced 1.6 times the proliferation of PDGF-BB (87 +/- 7 vs 55 +/- 5; n = 12; p &lt; 0.05). The effects of SP were blunted by a specific neurokinin-1 antagonist. Scatchard analysis indicated that SP binds to BM fibroblasts with an approximate Kd of 5 nM. SP induced steady state mRNA for IL-1 receptor IL-1RI and PDGF-BB (PDGF-AR, PDGF-BR) receptors by 7.5-, 6.2-, and 10.5-fold, respectively. Their up-regulation may be partly responsible for the synergistic effects of SP and their ligands. Induction (3-fold) of neurokinin-1 mRNA by IL-1alpha compared with no induction by PDGF-BB may explain the preferred synergism between SP and IL-1alpha. This study indicates that induction of SP, IL-1alpha, and PDGF-BB receptors is important to their synergistic effects on BM fibroblast proliferation. These results bring new insights into stroma-mediated hemopoietic regulation.