Role of Alpha-Fetoprotein in the Pathogenesis of Cancer

Alpha-fetoprotein (AFP) belongs to the albuminoid protein family and is considered as the fetal analog of serum albumin. This plasma protein is initially synthesized in the fetal liver and yolk sac and shows a maximum peak near the end of the first trimester. Later, concentrations begin to decline prenatally and drop precipitously after birth. This protein has three key ligand-binding pockets for interactions with various biomolecules. It contains multiple phosphorylation and acetylation sites for the regulation of physiological and pathophysiological states. High serum AFP titer is an established biomarker for yolk sac, embryonal and hepatocellular carcinoma. The present review critically analyzes the chemical nature, receptors, clinical implications, and therapeutic aspects of AFP, underpinning the development of different types of cancer.

Occupational Health in Practice: Heart Rate Profile of the Lathe Machine Workers

Context

Lathe machine work is an important unorganized sector in India. However, to date, no work physiological studies have been conducted among these workers to evaluate the physical strain involved in this work.

Aim

The present study aims to determine the workload in different lathe machine tasks from working heart rates (HRs) and certain cardiac indices.

Settings and Design

A cross-sectional study was conducted among 38 full-time male workers aged between 21 and 60 years.

Methods and Materials

The HR was measured directly during the productive work phase, additional work phase, and work pauses. Two cardiac strain indices, viz., net cardiac cost and relative cardiac cost were derived. The workload was also judged according to some standard acceptable criteria of physical strain.

Statistical Analysis Used

Mean and standard deviation were obtained for different categories of HR. Intergroup comparisons were conducted through one-way analysis of variance and the t-test.

Results

The mean working HR was found to be 99 beats per minute. A maximal working HR of 105 ± 6.1 beats per minute with a corresponding relative cardiac cost of 26% was obtained during the additional work phase.

Conclusions

The overall workload appeared to be moderate in nature. An acceptable criterion of cardiac cost of 30% appeared to be the most sensitive index in detecting workers experiencing a higher level of physical strain.

Integrated network-based multiple computational analyses for identification of co-expressed candidate genes associated with neurological manifestations of COVID-19

'Tripartite network' (TN) and 'combined gene network' (CGN) were constructed and their hub-bottleneck and driver nodes (44 genes) were evaluated as 'target genes' (TG) to identify 21 'candidate genes' (CG) and their relationship with neurological manifestations of COVID-19. TN was developed using neurological symptoms of COVID-19 found in literature. Under query genes (TG of TN), co-expressed genes were identified using pair-wise mutual information to genes available in RNA-Seq autopsy data of frontal cortex of COVID-19 victims. CGN was constructed with genes selected from TN and co-expressed in COVID-19. TG and their connecting genes of respective networks underwent functional analyses through findings of their enrichment terms and pair-wise 'semantic similarity scores' (SSS). A new integrated 'weighted harmonic mean score' was formulated assimilating values of SSS and STRING-based 'combined score' of the selected TG-pairs, which provided CG-pairs with properties of CGs as co-expressed and 'indispensable nodes' in CGN. Finally, six pairs sharing seven 'prevalent CGs' (ADAM10, ADAM17, AKT1, CTNNB1, ESR1, PIK3CA, FGFR1) showed linkages with the phenotypes (a) directly under neurodegeneration, neurodevelopmental diseases, tumour/cancer and cellular signalling, and (b) indirectly through other CGs under behavioural/cognitive and motor dysfunctions. The pathophysiology of 'prevalent CGs' has been discussed to interpret neurological phenotypes of COVID-19.

Pathophysiological effects of cadmium(II) on human health-a critical review

Cadmium(II) is an omnipresent environmental toxicant emitted from various industrial sources and by anthropogenic sources such as smoking. Cadmium(II) enters our body through various sources including contaminated food and drinks and from active or passive smoking. It spares no organs in our body and the calamities it invites include primarily nephrotoxicity, osteotoxicity, teratogenicity, endocrine disruption, hepatotoxicity and carcinogenicity above all. It brings about a bolt from the blue in the cellular biochemistry by generating reactive oxygen species (ROS), disrupting the factors involved in the repair of DNA lesions and many other toxic nuisances otherwise by modulating the cell signalling machinery and acting as a potent carcinogen above all. In this review, we have tried to decipher some of the mechanisms played by cadmium(II) in exhibiting its toxic effects on various system of our body.

Guanylin and uroguanylin: a promising nexus in intestinal electrolyte and fluid homeostasis

Intestinal guanyl peptides like guanylin and uroguanylin are the potent regulators of fluid-ion homeostasis. They are secreted from various cells of the intestinal mucosa, including enterochromaffin cells, epithelial cells, goblet cells, Paneth cells and others. These peptide hormones serve as ligands for receptor guanylyl cyclase-C (GC-C), which produces intracellular cyclic guanosine monophosphate (cGMP) and activates protein kinase G II (PKGII). cGMP/PKGII activates cystic fibrosis transmembrane conductance regulator for anion transport to the intestinal lumen, inhibits Na⁺/H⁺ exchanger that restricts H⁺ secretion and Na⁺ absorption, resulting in the retention of luminal fluid. These functions maintain intestinal pH, prevents hypernatremia and unwanted hypervolemic shock. Additionally, fluid balance in the intestine preserves the hydrated state of the colonic mucus that influences the growth of the commensal microorganisms and bowel clearance. Moreover, GC-C/cGMP signaling is involved in the regulation of intestinal barrier integrity, epithelial cell renewal, cell cycle, DNA damage repair, inflammatory responses, epithelial-mesenchymal transition and cancer progression. Impairment of GC-C activation causes functional gastrointestinal disorders, inflammatory bowel disease, visceral pain and colorectal cancer, suggesting that oral supplementation of guanyl peptide analogs (linaclotide, plecanatide) may prove useful for the treatment of these diseases.

Leptin and obesity

An imbalance between calorie intake and energy expenditure produces obesity. It has been a major problem in societies of the developing and developed world. In obesity an excessive amount of fat accumulates in adipose tissue cells as well as in other vital organs like liver, muscles, and pancreas. The adipocytes contain ob genes and express leptin, a 16 kDa protein. In the present communication, we reviewed the molecular basis of the etiopathophysiology of leptin in obesity. Special emphasis has been given to the use of leptin as a drug target for obesity treatment, the role of diet in the modulation of leptin secretion, and reduction of obesity at diminished level of blood leptin induced by physical exercise.

Matrix metallopeptidase 9 as a host protein target of chloroquine and melatonin for immunoregulation in COVID-19: A network-based meta-analysis

AIMS

The molecular pathogenesis of COVID-19 is similar to other coronavirus (CoV) infections viz. severe acute respiratory syndrome (SARS) in human. Due to scarcity of the suitable treatment strategy, the present study was undertaken to explore host protein(s) targeted by potent repurposed drug(s) in COVID-19.

MATERIALS AND METHODS

The differentially expressed genes (DEGs) were identified from microarray data repository of SARS-CoV patient blood. The repurposed drugs for COVID-19 were selected from available literature. Using DEGs and drugs, the protein-protein interaction (PPI) and chemo-protein interaction (CPI) networks were constructed and combined to develop an interactome model of PPI-CPI network. The top-ranked sub-network with its hub-bottleneck nodes were evaluated with their functional annotations.

KEY FINDINGS

A total of 120 DEGs and 65 drugs were identified. The PPI-CPI network (118 nodes and 293 edges) exhibited a top-ranked sub-network (35 nodes and 174 connectivities) with 12 hub-bottleneck nodes having two drugs chloroquine and melatonin in association with 10 proteins corresponding to six upregulated and four downregulated genes. Two drugs interacted directly with the hub-bottleneck node i.e. matrix metallopeptidase 9 (MMP9), a host protein corresponding to its upregulated gene. MMP9 showed functional annotations associated with neutrophil mediated immunoinflammation. Moreover, literature survey revealed that angiotensin converting enzyme 2, a membrane receptor of SARS-CoV-2 virus, might have functional cooperativity with MMP9 and a possible interaction with both drugs.

SIGNIFICANCE

The present study reveals that between chloroquine and melatonin, melatonin appears to be more promising repurposed drug against MMP9 for better immunocompromisation in COVID-19.

Sex and estrous cycle dependent changes in locomotor activity, anxiety and memory performance in aged mice after exposure of light at night

Light-at-night (LAN) can affect mammalian behaviour. But, the effects of LAN on aged rodents remain undefined yet. In the present investigation, aged Swiss Albino mice, habituated in regular light-dark cycle, were exposed to bright-light-pulse (1-h) at night on the day of study followed by experimentations for assessment of locomotor activities in the open field, anxiety in the elevated plus maze and short-term memory for novel object recognition (NOR) in the habituated field. Under without-bright-light exposure, (a) aged proestrous females showed greater locomotor activities and less anxiety than in aged diestrous females, (b) aged males showed locomotor activities and anxiety level similar to aged diestrous females and aged proestrous females respectively and (c) all animals failed to retain in object discrimination memory. LAN exposure exhibited the continual failure of such retention of memory while animals showed free and spontaneous exploration with thigmotactic behaviour having no object bias and/or phobia, but time stay in objects by animals altered variably among sexes and stages of estrous cycle. Overall, the LAN caused (a) diminution in locomotor activities, rise in anxiety and failure of memory for recognition of both familiar and novel objects in aged proestrous females, (b) hyperlocomotor activities and reduction in anxiety in both males and diestrous females with the failure of memory for recognition of novel objects only in aged males while diestrous females showed enhanced exploration time to both objects during NOR. Thus, nocturnal behaviour of aged mice varies with sex and estrous cycle and light acts differentially on them.

Assessment of cardiac strain in small - scale aluminium casting works

Background: The occupational health status scenario in unorganised sector is not impressive. There is a lack of awareness on occupational health and safety issues and manual labour is still obligatory. Ergonomic and work physiological studies conducted among different unorganised sector occupations are scanty. Aims and Objective: The present study intended a physiological evaluation of workload in small scale aluminium casting works. In accordance, cardiac strain of the workers is assessed in actual work situation. Methods: Seventeen regular male workers (mean age 32.6 ± 10.9; range 22 – 55) years, were examined for the magnitude of physiological strain. Different tasks performed were identified including work and rest hours. Working heart rate, net cardiac cost, relative cardiac cost and recovery heart rates were determined. Tasks performed were analysed in terms of heaviness, recommended strain level and thermal stress of the workplace. Results: Work study revealed the predominant static nature of the tasks performed. Overall strain of the job appeared to be moderate in nature with mean working heart rate of 99 ± 5.2 beats/min. Recovery patterns were inadequate for majority of the workers. Thermal stress prevailing was more than the recommended level. Conclusion: The subjects were exposed to cumulative circulatory stress which might have deleterious long term effect particularly on older workers. Interventions are required to ameliorate ergonomic stressors, which indicate further scope of study.DOI: http://dx.doi.org/10.3126/ijosh.v2i2.6565 International Journal of Occupational Safety and Health, Vol 2. No 2 (2012) 8-13 

Rise of cytosolic Ca2+ and activation of membrane-bound guanylyl cyclase activity in rat enterocytes by heat-stable enterotoxin of Vibrio cholerae non-01

The cytosolic calcium level ([Ca2+]i) and the membrane-bound guanylyl cyclase activity in the isolated rat intestinal epithelial cells were investigated. Heat-stable enterotoxin of Vibrio cholerae non-01 (NAG-ST) was found to increase both the [Ca2+]i and the enzyme activity. These changes occur similarly until 5 min of incubation with NAG-ST, indicating that these changes might be involved in NAG-ST induced signal transduction in rat enterocytes.

Binding of Escherichia coli heat-stable enterotoxin and rise of cyclic GMP in COLO 205 human colonic carcinoma cells

Escherichia coli heat-stable enterotoxin (STa) was found to bind on the surface of human colonic (COLO 205) cells. The binding of [125I]STa to cell membranes was found to be specific, reversible and saturable. Scatchard analysis of the equilibrium binding demonstrated a single class of binding sites with a Kd of 0.5 x 10(-10) M. Autoradiographic analysis of polyacrylamide gel electrophoresis revealed the specific incorporation of [125I]STa into a single STa binding protein with a molecular mass of 95 kDa. Following incubation of COLO 205 cells with STa, a rise of intracellular cGMP was also evident.

Comparison of cytosolic levels of calcium and G actin in diffuse and localised adherent Escherichia coli-infected HeLa cells

In the present study we compared the intracellular level of free calcium ([Ca2+]i) and monomeric (G)/total (G+F) actin ratio in HeLa cells infected with diffuse (DAEC) and localised adherent Escherichia coli (LAEC). The level of [Ca2+]i was increased in both DAEC- and LAEC-infected HeLa cells. However, studies with EGTA- and dantrolene-treated cells and also suspension of cells in Ca(2+)-free buffer suggested that the rise of [Ca2+]i in DAEC-infected cells was due to the influx of Ca2+ from extracellular medium, whereas Ca2+ mobilisation from the intracellular stores was responsible for the enhancement of [Ca2+]i in LAEC-infected cells. It was also evident that the infection of HeLa cells with DAEC and LAEC caused alteration of G/G+F actin ratio as compared to that of control cells. The ratio was much lower in LAEC-infected cells than that of DAEC-infected ones. Moreover, cytochalasin B inhibited both DAEC and LAEC invasion to HeLa cells, suggesting further the role of microfilaments in the invasion process.

Evidence for stimulation of the inositol triphosphate-Ca2+ signalling system in rat enterocytes by heat stable enterotoxin of Escherichia coli

In Escherichia coli heat stable enterotoxin (STa)-treated rat enterocytes, the rise of inositol triphosphate (IP3) preceded the rise of [Ca2+]i. Chelation of extracellular Ca2+ with EGTA and suspension of cells in Ca2+ free buffer both demonstrated the enterotoxin-induced initial rise of [Ca2+]i with a concomitant loss of sustained phase. Furthermore, pretreatment of cells with dantrolene resulted in a decrease of the early response of [Ca2+]i, indicating the initial effect of the rise of [Ca2+]i was mostly due to its mobilization from some IP3-sensitive intracellular stores.

Alteration of the microenvironment in plasma membranes of rat enterocytes after Escherichia coli heat stable enterotoxin treatment: effect on protein kinase C activity

Plasma membranes isolated from Escherichia coli heat stable enterotoxin (STa) treated rat enterocytes were studied in respect to protein kinase C activity and fluidity change. Pretreatment of enterocytes with STa increased the membrane bound protein kinase C activity about 5 fold as compared to control. STa treatment made the membrane more fluid as evident from a higher phospholipid/cholesterol ratio and greater unsaturated fatty acid levels. Moreover, the phase transition temperature of the STa treated membrane appeared to be significantly lower than that of the corresponding control membrane, thereby further indicating a rise in fluidity of the membrane in the former case. Our results, therefore, suggested that following STa enterotoxin treatment an appropriate fluid environment in the rat intestinal cell membrane was essential for the activation of protein kinase C.

Evidence for protein kinase C stimulation in rat enterocytes pretreated with heat stable enterotoxin of Escherichia coli

Rat intestinal epithelial cells were isolated and the activity of the calcium- and phospholipid-dependent protein kinase C (PKC) was investigated. The stimulation of activity by Escherichia coli heat stable enterotoxin (STa) was about 5-fold compared to control activity (16.91 +/- 1.69 vs 93.56 +/- 10.40 nmol/mg protein/min) and was dose dependent. Maximum enzyme activity was observed after incubation for 1 min with 6 ng of purified STa. The synergistic effects of calcium, phosphatidylserine and diolein on the enzyme activity were noted both in control and STa-treated cells. Staurosporine, a potent PKC inhibitor, significantly reduced the enzyme activity. Autoradiographic analysis of polyacrylamide gel electrophoresis revealed that pretreatment of the cells with STa also resulted in the phosphorylation of specific membrane proteins each with a molecular mass of 37 kDa, 100 kDa and 140 kDa. However, STa had no direct role on the enzyme activity. Our results, therefore, provide evidence for the involvement of PKC in STa-induced signal transduction in rat enterocytes.