A mathematical model to estimate percentage secondary infections from margin of error of diagnostic sensitivity: Useful tool for regulatory agencies to assess the risk of propagation due to false negative outcome of diagnostics

False negative outcome of a diagnosis is one the major reasons for the dissemination of the diseases with high risk of propagation. Diagnostic sensitivity and the margin of error determine the false negative outcome of the diagnosis. A mathematical model had been developed to estimate the mean % secondary infections based on the margin of error of diagnostic sensitivity, % prevalence and R0 value. This model recommends a diagnostic test with diagnostic sensitivity [≥] 96% and at least 92% lower bound limit of the 95% CI or [≤] 4% margin of error for a highly infectious diseases like COVID-19 to curb the secondary transmission of the infection due to false negative cases. Positive relationship was found between mean % secondary infection and margin of error of sensitivity suggesting greater the margin of error of a diagnostic test sensitivity, higher the number of secondary infections in a population due to false negative cases. Negative correlation was found between number of COVID-19 test kits (>90% sensitivity) with regulatory approval and margin of error (R= -0.92, p=0.023) suggesting lesser the margin of error of a diagnostic test, higher the chances of getting approved by the regulatory agencies. However, there are no specific regulatory standards available for margin of error of the diagnostic sensitivity of COVID-19 diagnostic tests. Highly infectious disease such as COVID-19, certainly need specific regulatory standards on margin of error or 95% CI of the diagnostic sensitivity to curb the dissemination of the disease due to false negative cases and our model can be used to set the standards such as sensitivity, margin of error or lower bound limit of 95% CI.

Effects of testosterone, estrogen and progesterone on TNF-α mediated cellular damage in rat arthritic synovial fibroblasts.

Sexual dimorphism is a well-established phenomenon in rheumatoid arthritis, with women exhibiting higher disease severity. Understanding the role of sex hormones using in vivo animal models is limited due to the systemic effects as well as the difficulty in exploring different dose combinations of the hormones simultaneously. However, cell culture systems pose ideal systems for exploring different combinations and concentrations of the hormones simultaneously. In this study, the procedure for isolation of arthritic fibroblasts was standardized using a combination of collagenase and trypsin based on maximal yield and viability after employing different enzymatic disaggregation procedures. The cultured synovial fibroblasts from arthritic rats did not differ significantly from normal rat fibroblasts in terms of proliferation or secretion of inflammatory mediators. Stimulation of fibroblasts with TNF-α was standardized and TNF-α stimulated rat arthritic synovial fibroblasts exhibited an ideal in vitro system for screening antiinflammatory molecules. The effects of physiological and pharmacological concentrations of testosterone, estrogen and progesterone were studied on TNF-α induced cellular damage in rat arthritic synovial fibroblasts. The results showed that estrogen and testosterone exerted antiinflammatory effects on rat arthritic synovial fibroblasts at physiological and pharmacological concentrations. However, there was no significant difference in the effects between physiological and pharmacological concentrations. Progesterone independently did not show any protective effects. In combination with physiological concentrations of estrogen, progesterone abrogated estrogen's protective effect but it exhibited protection in combination with pharmacological concentrations of estrogen.

Arjunolic acid: a novel phytomedicine with multifunctional therapeutic applications.

Herbal plants with antioxidant activities are widely used in Ayurvedic medicine for cardiac and other problems. Arjunolic acid is one such novel phytomedicine with multifunctional therapeutic applications. It is a triterpenoid saponin, isolated earlier from Terminalia arjuna and later from Combretum nelsonii, Leandra chaeton etc. Arjunolic acid is a potent antioxidant and free radical scavenger. The scientific basis for the use of arjunolic acid as cardiotonic in Ayurvedic medicine is proven by its vibrant functions such as prevention of myocardial necrosis, platelet aggregation and coagulation and lowering of blood pressure, heart rate and cholesterol levels. Its antioxidant property combined with metal chelating property protects organs from metal and drug induced toxicity. It also plays an effective role in exerting protection against both type I and type II diabetes and also ameliorates diabetic renal dysfunctions. Its therapeutic multifunctionality is shown by its wound healing, antimutagenic and antimicrobial activity. The mechanism of cytoprotection conferred by arjunolic acid can be explained by its property to reduce the oxidative stress by enhancing the antioxidant levels. Apart from its pathophysiological functions, it possesses dynamic insecticidal property and it is used as a structural molecular framework in supramolecular chemistry and nanoscience. Esters of ajunolic acid function as gelators of a wide variety of organic liquids. Experimental studies demonstrate the versatile effects of arjunolic acid, but still, further investigations are necessary to identify the functional groups responsible for its multivarious effects and to study the molecular mechanisms as well as the probable side effects/toxicity owing to its long-term use. Though the beneficial role of this triterpenoid has been assessed from various angles, a comprehensive review of its effects on biochemistry and organ pathophysiology is lacking and this forms the rationale of this review.

Myocardial expression of PDECGF is associated with extracellular matrix remodeling in experimental myocardial infarction in rats.

Platelet-derived endothelial cell growth factor (PDECGF) is a potent angiogenic peptide with anti-apoptotic activity expressed widely in tumours. However, its expression in myocardial infarction (MI) is not yet established. This study aimed to assess the myocardial expression of PDECGF in rats after MI. Extracellular matrix (ECM) remodeling plays an important role in angiogenesis; hence, changes in the ECM components were investigated in the myocardium after MI, which was induced in rats by coronary artery ligation (CAL) and verified using biochemical markers and histopathology. Immunohistochemistry, RT-PCR, and activity assays identified the expression pattern of PDECGF on days 1, 2, 4, 8, 16, and 32 after CAL. The levels of TNF-alpha, MMP-2, collagen, and glycosaminoglycans in the ECM were assessed. Studies on immunohistochemistry, RT-PCR, and PDECGF activity demonstrated elevated levels of PDECGF expression from day 2 after CAL. Macrophages, endothelial cells, fibroblasts, and cardiomyocytes, especially at the border region of the lesion, showed an enhanced expression for PDECGF. Remodeling of the ECM was depicted by changes in the levels of TNF-alpha, MMP-2, collagen, and GAG. Hence, this study clearly indicated PDECGF as an important angiogenic molecule expressed during MI and the alterations in ECM components facilitated the process of angiogenesis.

Platelet-derived endothelial cell growth factor mediates angiogenesis and antiapoptosis in rat aortic endothelial cells.

This study explores the angiogenic and antiapoptotic activities of platelet-derived endothelial cell growth factor (PDECGF) in rat aortic endothelial cells. The effects of PDECGF on rat aortic endothelial cell (RAEC) proliferation, migration, chemotaxis, and tubule formation were investigated in vitro at various concentrations viz., 1, 2, 4, 8, 16, and 32 ng x mL(-1) on endothelial cells. Endothelial cells were induced with hypoxic stress and the antiapoptotic effects of PDECGF were analysed by cell survival assay, fluorescence microscopy, cell viability assay, and flow cytometry. The results demonstrated the angiogenic potential of PDECGF on endothelial cells in a dose-dependent manner. PDECGF at 16 and 32 ng x mL(-1) increased cell proliferation (>80%), induced cell migration (>4 fold), stimulated chemotaxis (>2 fold), and increased tubule formation (>3 fold) compared with the control. Studies on hypoxic stress revealed the antiapoptotic nature of PDECGF on endothelial cells. PDECGF treatment enhanced cell survival by 14%, as well as cell viability by 13%, and decreased the percentage of apoptotic cells by 13% as demonstrated by fluorescence-activated cell sorter studies (FACS). In conclusion, this study demonstrated the angiogenic and antiapoptotic potentials of PDECGF on RAEC.

Low frequency pulsed electromagnetic field--a viable alternative therapy for arthritis.

Arthritis refers to more than 100 disorders of the musculoskeletal system. The existing pharmacological interventions for arthritis offer only symptomatic relief and they are not definitive and curative. Magnetic healing has been known from antiquity and it is evolved to the present times with the advent of electromagnetism. The original basis for the trial of this form of therapy is the interaction between the biological systems with the natural magnetic fields. Optimization of the physical window comprising the electromagnetic field generator and signal properties (frequency, intensity, duration, waveform) with the biological window, inclusive of the experimental model, age and stimulus has helped in achieving consistent beneficial results. Low frequency pulsed electromagnetic field (PEMF) can provide noninvasive, safe and easy to apply method to treat pain, inflammation and dysfunctions associated with rheumatoid arthritis (RA) and osteoarthritis (OA) and PEMF has a long term record of safety. This review focusses on the therapeutic application of PEMF in the treatment of these forms of arthritis. The analysis of various studies (animal models of arthritis, cell culture systems and clinical trials) reporting the use of PEMF for arthritis cure has conclusively shown that PEMF not only alleviates the pain in the arthritis condition but it also affords chondroprotection, exerts antiinflammatory action and helps in bone remodeling and this could be developed as a viable alternative for arthritis therapy.

Estrogen and testosterone attenuate extracellular matrix loss in collagen-induced arthritis in rats.

Rheumatoid arthritis (RA) is a sexually dimorphic, autoimmune inflammatory disorder affecting the joints. Joint disability in RA results primarily from loss of matrix components (collagen and glycosoaminoglycan) in the cartilage and synovium. This study was carried out to understand the effect of physiological levels of testosterone, estrogen, and progesterone on oxidative stress-induced changes in matrix composition in rat synovium in arthritis. Arthritis induction in castrated and ovariectomized rats resulted in enhanced oxidative stress and this was assessed by lipid peroxidation levels and depletion of antioxidants. This, in turn, led to significantly (p < 0.01) increased levels of TNF-alpha and matrix metalloproteinase-2 (MMP-2), subsequently resulting in loss of collagen, elastin, and glycosoaminoglycan (GAG) and disorganization of reticulin as evidenced by biochemical quantitation and also by staining for collagen, reticulin, and elastin. Treatment with physiological doses of dihydrotestosterone (25 mg topically) and estrogen (5 microg/0.1 ml subcutaneously) restored the antioxidant levels significantly (p < 0.05) and reduced the levels of TNF-alpha and MMP-2, with estrogen exhibiting a higher potency. This, in turn, attenuated the damage to reticulin organization as well as the loss of collagen and GAG in the articular tissues. However, elastin loss could not be attenuated by either treatment. Progesterone (2 mg/0.1 ml subcutaneously) was not shown to have any significance in disease modification, and on the contrary, it inhibited the protective effects of estrogen. However, progesterone contributed to increased collagen levels in the tissues.

Comparative studies on the interplay of testosterone, estrogen and progesterone in collagen induced arthritis in rats.

Rheumatoid arthritis (RA) is a sexually dimorphic autoimmune disorder exhibiting a higher disease prevalence and severity among females. This study was carried out to understand the role of the major sex hormones viz., testosterone, estrogen and progesterone on the severity in arthritis. The interplay of the sex hormones was studied in a rat model of collagen induced arthritis (CIA). The parameters used for analyzing the disease severity included paw volume, radiology, histopathology of joint, markers for bone turnover, cytokine profile, levels of pain mediator (prostaglandin E(2)) and immune response to type II collagen. Arthritis induction to castrated and ovariectomised rats resulted in enhanced inflammation thereby indicating the importance of sex hormones. Treatment with physiological doses of dihydrotestosterone and estrogen attenuated the inflammation, with estrogen exhibiting higher potency. Progesterone was not shown to have any significance in disease modification; however, when progesterone was administered in combination with estrogen, the protective effects of estrogen were noticed to decrease.

Myocardial ischemia and reperfusion injury in rats: lysosomal hydrolases and matrix metalloproteinases mediated cellular damage.

The aim of this study was to evaluate the time course events of cellular damage during myocardial ischemia and reperfusion injury in rats and to find out a correlation between the structural alterations with respect to the biochemical changes. Cardiac biomarkers and lysosomal enzymes viz. cathepsin D, acid phosphatase and beta-glucuronidase and matrix metalloproteinases (MMPs) were evaluated at different time points, in response to ischemia-reperfusion induced oxidative stress in an isolated rat heart model perfused in Langendorff mode. Microscopically, changes in myocardial architecture, myofibrillar degradation, and collagen (COL) integrity were studied using hematoxylin-eosin, Masson's trichrome and toluidine blue staining techniques. A three-fold increase in the level of myoglobin was observed after 30 min of ischemia followed by 120 min of reperfusion as compared to 15 min ischemia, 120 min reperfusion. Similarly, a significant increase (P<0.05) in the levels of lipid peroxides and superoxide anion coupled with a decrease in enzymatic and nonenzymatic antioxidant levels were observed. A concomitant increase in the activity of cathepsin D (24.07+/-0.95) and a higher expression of MMPs after 120 min of reperfusion following 30 min ischemia were shown to correlate with the myocardial damage as shown by histopathology, suggesting that free radical induced activation of cathepsin D and MMPs could mediate early damage during myocardial ischemia and reperfusion.

Of humans and canines: a comparative evaluation of heat shock and apoptosis-associated proteins in mammary tumors.

BACKGROUND: Mammary tumors are the most common neoplasms in humans and canines. Human and canine mammary tumors share several important epidemiological, clinicopathological and biochemical features. Dysregulation of normal programmed cell death mechanisms play an important role in the pathogenesis and progression of breast cancer. We investigated the expression of heat shock proteins (Hsps) as well as apoptosis-associated proteins in both human and canine mammary tumors. METHODS: Twenty breast cancer patients who were categorized as pre- and postmenopausal and 20 mammary gland tumors obtained from dogs were included in this study The expression of Bcl-2, Bcl-X(L), Bax, caspases 8 and 3 as well as Hsp 70 and 90 in tumor tissues and adjacent tissues were investigated using Western blotting. RESULTS: While expression of Bcl-2, Bcl-X(L), Hsp 70 and 90 was increased, expression of Bax and caspases 8 and 3 was significantly lower in both human as well as canine mammary tumor tissues compared to corresponding adjacent tissues. The magnitude of the changes was however more pronounced in premenopausal patients compared to postmenopausal patients. CONCLUSIONS: The shift of balance towards expression of Hsp and antiapoptotic proteins may lead to evasion of apoptosis both in humans and canines. The similar pattern of changes in Hsps and apoptosis-associated proteins in human and canine mammary tumors validate use of the canine model to understand the molecular mechanisms of mammary carcinogenesis.