Sentiment analysis and its applications in fighting COVID-19 and infectious diseases: A systematic review

The COVID-19 pandemic caused by the novel coronavirus SARS-CoV-2 occurred unexpectedly in China in December 2019. Tens of millions of confirmed cases and more than hundreds of thousands of confirmed deaths are reported worldwide according to the World Health Organisation. News about the virus is spreading all over social media websites. Consequently, these social media outlets are experiencing and presenting different views, opinions and emotions during various outbreak-related incidents. For computer scientists and researchers, big data are valuable assets for understanding people's sentiments regarding current events, especially those related to the pandemic. Therefore, analysing these sentiments will yield remarkable findings. To the best of our knowledge, previous related studies have focused on one kind of infectious disease. No previous study has examined multiple diseases via sentiment analysis. Accordingly, this research aimed to review and analyse articles about the occurrence of different types of infectious diseases, such as epidemics, pandemics, viruses or outbreaks, during the last 10 years, understand the application of sentiment analysis and obtain the most important literature findings. Articles on related topics were systematically searched in five major databases, namely, ScienceDirect, PubMed, Web of Science, IEEE Xplore and Scopus, from 1 January 2010 to 30 June 2020. These indices were considered sufficiently extensive and reliable to cover our scope of the literature. Articles were selected based on our inclusion and exclusion criteria for the systematic review, with a total of n = 28 articles selected. All these articles were formed into a coherent taxonomy to describe the corresponding current standpoints in the literature in accordance with four main categories: lexicon-based models, machine learning-based models, hybrid-based models and individuals. The obtained articles were categorised into motivations related to disease mitigation, data analysis and challenges faced by researchers with respect to data, social media platforms and community. Other aspects, such as the protocol being followed by the systematic review and demographic statistics of the literature distribution, were included in the review. Interesting patterns were observed in the literature, and the identified articles were grouped accordingly. This study emphasised the current standpoint and opportunities for research in this area and promoted additional efforts towards the understanding of this research field.

Schwann cell phenotype is regulated by axon modality and central-peripheral location, and persists in vitro

Myelinating Schwann cells express distinct sensory and motor phenotypes as defined by their differing patterns of growth factor production (Hoke et al., 2006). The heterogeneous growth factor requirements of sensory and motor neurons, however, suggest that Schwann cell phenotype might vary across a broad spectrum. To explore this possibility, we selectively denervated six discrete Schwann cell populations: dorsal root, cutaneous nerve, cutaneous unmyelinated axons, muscle nerve afferents, muscle nerve efferents, and ventral root. Real-time RT-PCR for 11 growth factors was performed on the 6 target Schwann cell populations 5, 15, and 30 days after their denervation, and on normal cutaneous nerve, muscle nerve, ventral root, and dorsal root to establish baseline expression levels. Within the denervated axon populations, IGF-1 and VEGF were expressed most prominently in cutaneous nerve, HGF, NGF, and BDNF in cutaneous nerve and dorsal root, GDNF in dorsal root and ventral root, PTN in the ventral root and muscle nerve efferents, and IGF-2 in both afferents and efferents within muscle nerve; expression of CNTF, FGF-2 and NT-3 was not modality or location specific. ELISA for NGF, BDNF, and GDNF confirmed that gene expression correlated with protein concentration. These findings demonstrate that growth factor expression by denervated Schwann cells is not only subject to further regulation within the previously-defined sensory and motor groups, but also varies along a central-peripheral axis. The traditional view of myelinating Schwann cells as a homogenous population is modified by the realization that complex regulation produces a wide variety of Schwann cell phenotypes. Additionally, we found that Schwann cell phenotype is maintained for 2 weeks in vitro, demonstrating that it may survive several cell divisions without instructive cues from either axons or basal lamina.

A comparison of two different techniques for the detection of blood parasite, Theileria annulata, in cattle from two districts in Khyber Pukhtoon Khwa Province (Pakistan)

The present study was carried out to determine the prevalence of Theileria annulata in large ruminants from two districts, Peshawar and Kohat, in Khyber Pukhtoon Khwa (Pakistan). Blood samples were collected from 95 cattle. Data on the characteristics of animals and herds were collected through questionnaires. No significant risk factors were found associated with the spread of tropical theileriosis in the study area. Two different parasite detection techniques, PCR amplification and screening of Giemsa stained slides, were compared and it was found that PCR amplification is a more sensitive tool (33.7% parasite detection), as compared to smear scanning (5.2% parasite detection) for the detection of Theileria annulata. 32 out of 95 animals, from both districts, produced the 721-bp fragment specific for Theileria annulata.

Use of capecitabine in management of early colon cancer

Capecitabine (Xeloda^®, Roche, Basel, Switzerland) is a pro-drug of 5-fluorouracil (5-FU), and it is converted to 5-FU in the cancer cell by enzymatic degradation. The role of capecitabine in colorectal cancer has evolved in the last 15 years. In early trials in the metastatic setting, capecitabine has shown superior response rates compared with those achieved with 5-FU (Mayo Clinic regimen) (26% vs 17%), with equivalent progression-free survival and overall survival. In the adjuvant setting, the Xeloda in Adjuvant Colon Cancer Therapy (X-ACT) trial demonstrated that capecitabine as a single agent led to improvement in relapse-free survival (hazard ratio: 0.86, 95% confidence interval: 0.74–0.99, P = 0.04) and was associated with significantly fewer adverse events than 5-FU plus leucovorin (LV, folinic acid). On the basis of the X-ACT trial, capecitabine was approved by the United States Food and Drug Administration, the National Institute for Clinical Excellence, and the Scottish Medicines Consortium as monotherapy for the adjuvant treatment of stage III colon cancer. The next step was to incorporate capecitabine into combination therapy. The XELOXA trial studied the combination of capecitabine and oxaliplatin (XELOX) vs 5-FU/LV and demonstrated 5-year disease-free survival of 66% for XELOX, compared with 60% for 5-FU/LV. The toxicity profile was also quite comparable in the two arms. So both the single agent use of capecitabine as well as in combination with oxaliplatin can be considered as part of the standard of care in management of early colon cancer in appropriately selected patient groups.

Upper gastrointestinal endoscopy findings in Nigerians: a review of 170 cases in Lagos

BACKGROUND

The advent of flexible endoscopy has made it possible to visualise the mucosa of virtually the entire intestine. This service is yet to be widely available in Nigeria. Existing reports on indications and findings at endoscopies are sometimes conflicting, with some recent reports suggesting a changing pattern of gastrointestinal diseases.

OBJECTIVE

The study set out to evaluate the indications, endoscopic findings and their frequencies as well as any adverse outcome from the endoscopic examinations.

METHODOLOGY

This was a retrospective study in which we reviewed the endoscopy records of the first one hundred and seventy patients that underwent upper gastrointestinal endoscopy at the Lagos State University Teaching Hospital. The patients' bio data, indications and findings during endoscopic examinations as well as any adverse outcome were documented. Data obtained were analysed using SPSS version 11.

RESULTS

The majority of the patients were in the middle to elderly age with a peak in the 5th decade. The commonest indications for upper gastrointestinal endoscopy were; Dyspepsia, upper gastrointestinal haemorrhage, previously diagnosed peptic ulcer unresponsive to treatment and retrosternal discomfort or pain. Endoscopic request for variceal screening were uncommon. The commonest endoscopic findings were; features of gastroesophageal reflux disease, followed by gastroduodenitis (non-ulcer mucosal lesions in stomach and duodenum) and peptic ulcer disease. In 14 patients the endoscopy examination revealed normal findings.

CONCLUSION

The role of endoscopy in the diagnosis and management of gastrointestinal disorders cannot be overemphasised. It is hereby recommended that provision of endoscopic facilities and training of necessary personnel be encouraged by all relevant agencies so that the services can be accessible and affordable by all who require it in view of its importance in patient management.

Schwann cells express motor and sensory phenotypes that regulate axon regeneration

Schwann cell phenotype is classified as either myelinating or nonmyelinating. Additional phenotypic specialization is suggested, however, by the preferential reinnervation of muscle pathways by motoneurons. To explore potential differences in growth factor expression between sensory and motor nerve, grafts of cutaneous nerve or ventral root were denervated, reinnervated with cutaneous axons, or reinnervated with motor axons. Competitive reverse transcription-PCR was performed on normal cutaneous nerve and ventral root and on graft preparations 5, 15, and 30 d after surgery. mRNA for nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor, hepatocyte growth factor, and insulin-like growth factor-1 was expressed vigorously by denervated and reinnervated cutaneous nerve but minimally by ventral root. In contrast, mRNA for pleiotrophin (PTN) and glial cell line-derived neurotrophic factor was upregulated to a greater degree in ventral root. ELISA confirmed that NGF and BDNF protein were significantly more abundant in denervated cutaneous nerve than in denervated ventral root, but that PTN protein was more abundant in denervated ventral root. The motor phenotype was not immutable and could be modified toward the sensory phenotype by prolonged reinnervation of ventral root by cutaneous axons. Retrograde labeling to quantify regenerating neurons demonstrated that cutaneous nerve preferentially supported cutaneous axon regeneration, whereas ventral root preferentially supported motor axon regeneration. Schwann cells thus express distinct sensory and motor phenotypes that are associated with the support of regeneration in a phenotype-specific manner. These findings suggest that current techniques of bridging gaps in motor and mixed nerve with cutaneous graft could be improved by matching axon and Schwann cell properties.

Induction of fibroblast spreading by Mn2+: a possible role for unusual binding sites for divalent cations in receptors for proteins containing Arg-Gly-Asp

Mn2+ at low (microM) concentrations fulfils the divalent cation requirement for spreading of BHK21 cells on fibronectin. At much higher concentrations, Mn2+ (and to a small extent also Mg2+) induces spreading on haemoglobin, not normally an adhesive protein. Since high Mn2+ also induces spreading of BHK variants unresponsive to exogenous fibronectin, it is unlikely to be acting as a cofactor for secreted cellular fibronectin or by stimulating its secretion. High Ca2+, but not Mg2+, inhibits the induction of spreading by Mn2+ on haemoglobin. Pre-treatment of cells with high concentrations of trypsin decreases the rate of spreading induced by Mg2+ on fibronectin, and by Mn2+ on haemoglobin, to similar extents. High and low Mn2+ could induce spreading, either by different mechanisms or through a common pathway. In the second case, at both concentrations, Mn2+ could act by binding to Ca2+/Mg2+ sites in one or more receptors for adhesion proteins. This would require binding of Mn2+ or Mg2+ to these sites to activate the receptors in the absence of adhesion proteins, and the effect of such proteins to be to increase the affinity of the sites for metal ions. The sites in question may be formed by sequences homologous to those found in the extracellular domains of the vitronectin receptor and platelet membrane glycoprotein IIb. Although very similar to the Ca2+-binding loop in the EF hand of calmodulin, these sequences more closely resemble bacterial galactose-binding protein in lacking one of the conserved co-ordinating side-chains.