Association of Marijuana Use and Cardiovascular Disease: A Behavioral Risk Factor Surveillance System Data Analysis of 133,706 US Adults

BackgroundMarijuana is the most commonly used psychoactive drug, while its effects on cardiovascular health are not well known and remain a subject of interest.MethodsWe used the pooled 2016-2018 data from the Behavioral Risk Factor Surveillance System to perform a cross-sectional analysis evaluating the association of marijuana and cardiovascular disease among US adults who never smoked cigarettes.ResultsAmong US adults ages 18-74 years, when compared with nonusers, frequent marijuana use was associated with 88% higher odds of myocardial infarction or coronary artery disease (adjusted odds ratio [aOR] 1.88; 95% confidence interval [CI], 1.15-3.08), and 81% higher odds of stroke (aOR 1.81; 95% CI, 1.14-2.89). Among the premature cardiovascular disease group, frequent marijuana users had 2.3 times higher odds of myocardial infarction or coronary artery disease (aOR 2.27; 95% CI, 1.20-4.30), and 1.9 times higher odds of stroke (aOR 1.92; 95% CI, 1.07-3.43). In terms of the modality of marijuana use, frequent marijuana smoking had 2.1 times higher odds of myocardial infarction or coronary artery disease (aOR 2.07; 95% CI, 1.21-3.56), and 1.8 times higher odds of stroke (aOR 1.84; 95% CI, 1.09-3.10). A similar association was observed in the premature cardiovascular disease group who smoked marijuana (aOR [for myocardial infarction or coronary artery disease] 2.64; 95% CI, 1.37-5.09; aOR [for stroke] 2.00; 95% CI, 1.05-3.79). No association was observed between marijuana use in any form other than smoking and cardiovascular disease, across all age groups.ConclusionFrequent marijuana smoking is associated with significantly higher odds of stroke and myocardial infarction or coronary artery disease, with a possible role in premature cardiovascular disease.     

Strain-enhanced stress relaxation impacts nonlinear elasticity in collagen gels

The extracellular matrix (ECM) is a complex assembly of structural proteins that provides physical support and biochemical signaling to cells in tissues. The mechanical properties of the ECM have been found to play a key role in regulating cell behaviors such as differentiation and malignancy. Gels formed from ECM protein biopolymers such as collagen or fibrin are commonly used for 3D cell culture models of tissue. One of the most striking features of these gels is that they exhibit nonlinear elasticity, undergoing strain stiffening. However, these gels are also viscoelastic and exhibit stress relaxation, with the resistance of the gel to a deformation relaxing over time. Recent studies have suggested that cells sense and respond to both nonlinear elasticity and viscoelasticity of ECM, yet little is known about the connection between nonlinear elasticity and viscoelasticity. Here, we report that, as strain is increased, not only do biopolymer gels stiffen but they also exhibit faster stress relaxation, reducing the timescale over which elastic energy is dissipated. This effect is not universal to all biological gels and is mediated through weak cross-links. Mechanistically, computational modeling and atomic force microscopy (AFM) indicate that strain-enhanced stress relaxation of collagen gels arises from force-dependent unbinding of weak bonds between collagen fibers. The broader effect of strain-enhanced stress relaxation is to rapidly diminish strain stiffening over time. These results reveal the interplay between nonlinear elasticity and viscoelasticity in collagen gels, and highlight the complexity of the ECM mechanics that are likely sensed through cellular mechanotransduction.The composition and architecture of ECM is heterogeneous and varies with tissue type and location. One particularly important ECM protein is type Ι collagen, which is the most abundant ECM component and primarily determines the mechanics of connective tissue (1). Type 1 collagen self-assembles into fibers, and these fibers can form networks in vitro. Studies investigating the mechanical properties of collagen networks have revealed that these networks are nonlinearly elastic and exhibit strain stiffening, or an increase in the elasticity as the strain on the network is enhanced (1–3). This nonlinear elasticity is also a characteristic feature of fibrin gels, which serve as the major component of blood clots, as well as in reconstituted networks of intermediate filaments and cytoskeletal actin networks (2, 4–7). These networks are all composed of semiflexible polymers or fibers, which are relatively rigid, so that the tangent to the contour of the polymer is correlated over long lengths, yet undergo substantial bending fluctuations due to thermal energy. Semiflexible polymers or fibers form networks at low volume fractions (8). Strain stiffening in these networks is thought to arise from either the entropic elasticity of single polymers resisting extension (entropic model) (2, 5), or from alignment of fibers in the direction of strain with a corresponding transition to a regime of elasticity dominated by fiber stretching at higher strains (nonentropic model) (5, 7, 9, 10). Although it has long been known that cells sense and respond to the elastic modulus of ECMs (11–14), recent work has indicated an impact of nonlinear elasticity as well. Studies have found that the nonlinear elasticity of ECM regulates modes of cell motility (15) and differentiation of mesenchymal stem cells (16), alters how far cells are able to sense into the ECM (17), and enables long-range mechanical signaling between cells (18).In addition to often displaying nonlinear elasticity, most biological gels are viscoelastic and exhibit a time-dependent elastic modulus. These gels undergo stress relaxation in response to an applied strain: the initial stress resisting an applied strain decreases over time due to reorganization processes that relax the stresses in the matrix. In the case of collagen gels typically used for in vitro studies, viscoelasticity and stress relaxation likely arise from unbinding of the weak interactions, such as hydrophobic and electrostatic forces, which hold the fibers in a network (19–21). Interestingly, recent studies have found that viscoelasticity in synthetic hydrogels used as cell culture substrates can influence cell behaviors such as spreading, proliferation, and differentiation (22–25). The nonlinear elasticity of collagen and fibrin is dependent on the history of applied strains, indicating an influence of viscoelasticity on nonlinear elasticity (19). Here, we directly investigate the coupling between viscoelasticity and nonlinear elasticity for various gels, and find that increased strain leads to faster stress relaxation in collagen and fibrin gels. In collagen gels, these results can be explained by force-dependent unbinding of cross-links, and indicate a mechanism whereby strain stiffening is rapidly dissipated.     

Role of inflammatory mediators in the suppression of insulin receptor phosphorylation in circulating mononuclear cells of obese subjects

Aims/hypothesis Obesity is associated with insulin resistance and inflammation. The circulating human mononuclear cell (MNC) has been shown to respond to low-dose insulin infusion. We have now investigated whether in obesity: (1) phosphorylated insulin receptor beta subunit (p-INSR-β) is reduced in the MNC; (2) pro-inflammatory mediators including inhibitor of kappa light polypeptide gene enhancer in B cells-kinase beta (IKBKB), suppressor of cytokine signalling-3 (SOCS) and protein kinase C-beta 2 (PRKCB2) are increased and related to p-INSR-β; and (3) the reduction in MNC p-INSR-β is related to the reduction in insulin sensitivity. Materials and methods MNCs were prepared from fasting blood samples of 16 normal weight and 16 obese female subjects. Results Our data show that p-INSR-β is reduced significantly in MNCs from obese subjects compared with that of normal controls. MNCs from obese subjects have higher IKBKB expression, increased nuclear factor kappa B (NFκB) binding and higher mRNA expression of TNFAIP1 and IL6 genes. NFκB binding, TNFAIP1 mRNA and plasma C-reactive protein are inversely related to p-INSR-β. PRKCB2 mRNA and protein expression were significantly higher in the obese subjects and were related significantly to pro-inflammatory mediators but not to p-INSR-β. SOCS3 mRNA expression was markedly elevated and positively related to pro-inflammatory mediators including IKBKB and PRKCB2 on the one hand and inversely related to p-INSR-β on the other. Conclusions/interpretation We conclude that in obesity the MNC is characterised by reduced p-INSR-β and increased inflammatory mediators including IKBKB, PRKCB2 and SOCS3. The increase in SOCS3 but not IKBKB or PRKCB2 is related inversely to p-INSR-β and might mediate the inhibition of p-INSR-β. These data elucidate the relationship between inflammation and insulin resistance using the MNC as a model. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible to authorised users.     

Status of HFE mutation in thalassemia syndromes in north India

Hereditary hemochromatosis is an autosomal recessive and most commonly inherited single gene disorder among Caucasians, with a prevalence of 5 per 1,000 and a carrier frequency of 1 in 10. Two point mutations were described and are referred as C282Y and H63D. In the present study, we have analyzed 729 north Indian samples for C282Y and H63D mutations. Of these, no allele of the C282Y mutation was seen, while 3 homozygous and 43 heterozygous for the H63D mutation were seen in the patients of thalassemia group. However, 47 cases were found heterozygous for the H63D mutation among the normal groups (11.16%).     

Protease inhibitors stimulate hematopoiesis and decrease apoptosis and ICE expression in CD34(+) cells

Highly active retroviral therapy has been associated with a decline in the frequency of cytopenia in patients with human immunodeficiency virus (HIV) infection. This may result from lower hematologic toxicity of newer antiviral drugs and their increased efficacy against HIV-1. Protease inhibitors, in addition to their effects on HIV replication, appear to affect various cellular functions. Recently, it was reported that ritonavir inhibited caspase-1 expression in normal CD4(+) cells. It was hypothesized that protease inhibitors may improve hematopoietic function owing to their direct effects on the bone marrow progenitor cells. When ritonavir was added to methylcellulose cultures of bone marrow cells from HIV-infected patients and normal controls, colony formation increased 2.4-fold (n = 5) in control cultures and 4-fold (n = 5) in cultures of cells from HIV-infected patients. In the presence of ritonavir, cultures of CD34(+) cells showed markedly decreased apoptosis in comparison with untreated cultures (45% decrease in apoptotic cell number; n = 6). A synthetic inhibitor of caspase 1 (Ac-Tyr-Val-Ala-Asp-aldehyde [single-letter amino acid codes]), which inhibits activation of several caspases including CPP32 and interleukin 1beta-converting enzyme (ICE or caspase 1), also decreased the rate of apoptosis and enhanced colony formation by progenitor cells derived from HIV-infected patients (3-fold; n = 5). In ritonavir-treated samples derived from HIV-infected individuals, the number of cells expressing ICE also decreased. In conclusion, HIV protease inhibitors may, by blocking the caspase-dependent apoptotic pathway, overcome inhibition of hematopoiesis seen in patients with HIV infection, an effect unrelated to their antiviral activity. (Blood. 2000;96:2735-2739)     

Cationic liposomes as non-viral carriers of gene medicines: resolved issues, open questions, and future promises

The clinical success of gene therapy is critically dependent on the development of efficient and safe gene delivery reagents, popularly known as "transfection vectors." The transfection vectors commonly used in gene therapy are mainly of two types: viral and non-viral. The efficiencies of viral transfection vectors are, in general, superior to their non-viral counterparts. However, the myriads of potentially adverse immunogenic aftermaths associated with the use of viral vectors are increasingly making the non-viral gene delivery reagents as the vectors of choice. Among the existing arsenal of non-viral gene delivery reagents, the distinct advantages associated with the use of cationic transfection lipids include their: (a) robust manufacture; (b) ease in handling and preparation techniques; (c) ability to inject large lipid:DNA complexes; and (d) low immunogenic response. The present review highlights the major achievements in the area of designing efficacious cationic transfection lipids, some of the more recent advances in the field of cationic liposomes-mediated gene transfer and targeted gene delivery, some unresolved issues and challenges in liposomal gene delivery, and future promises of cationic liposomes as gene-carriers in non-viral gene therapy.     

Toll-like receptors and chronic lung disease

TLRs (Toll-like receptors) comprise a family of proteins whose function is principally to facilitate the detection of, and response to, pathogens. Protozoa, helminths, viruses, bacteria and fungi can all activate TLR signalling, and these signals have important roles in the activation of host defence. TLRs may also respond to products of tissue damage, providing them with roles in infective and sterile inflammation. Their role as detectors of pathogens and pathogen-associated molecules provides molecular mechanisms to underpin the observations leading to the hygiene hypothesis. Targeting of TLR signalling has implications in the control of infection, vaccine design, desensitization to allergens and down-regulation of inflammation. This review will explore TLR history, molecular signalling and the potential roles of TLRs in chronic lung disease.     

Acute hemodynamic changes during intravenous dipyridamole thallium imaging early after infarction

In order to determine the safety and hemodynamic effects of intravenous dipyridamole infusion for thallium-201 scinitigraphy in patients with acute ischemic syndromes, 10 patients with recent uncomplicated myocardial infarction (7 +/- 2 days pre-test) had central pressures and cardiac output values measured serially in a coronary care unit during and after the administration of dipyridamole (0.56 mg/kg over 4 minutes) and following aminophylline reversal (50 to 150 mg intravenously) of dipyridamole effect. Cardiac medications were not discontinued. Double product did not change significantly (8522 +/- 1811 versus 9044 +/- 1701; p = NS). Serious ischemic events did not occur, although 20% of patients had noncardiac side effects and 30% developed greater than or equal to 1 mm ST segment depression with associated angina in one-third of these cases. The peripheral blood pressure and heart rate response did not predict the occurrence of myocardial ischemia. Dipyridamole significantly reduced systemic vascular resistance (1218 +/- 302 to 739 +/- 166 dyne/sec-1/cm-5; p less than 0.05) and increased cardiac index (3.1 +/- 0.7 to 4.7 +/- 1.0 L/min/m2; p less than 0.05) within approximately 10 minutes, in association with a significant increase in pulmonary capillary wedge pressure (13 +/- 5 to 17 +/- 6 mm Hg; p less than 0.05). Three patients developed silent new "V" waves in their pulmonary capillary wedge pressure tracing, associated with anterior thallium redistribution. All three patients with newly elevated wedge pressures (greater than 15 mm Hg) had both thallium-201 redistribution and multivessel coronary disease.(ABSTRACT TRUNCATED AT 250 WORDS)     

Occult hepatitis B virus infection in chronic liver disease: full-length genome and analysis of mutant surface promoter

BACKGROUND AND AIMS: Genome sequence of hepatitis B virus (HBV) from occult chronic infection is scarce. Fifty-six (9.4%) of 591 patients seronegative for hepatitis B surface antigen (HBsAg) with chronic liver disease were positive for HBV DNA. The complete HBV genome from 9 of these patients (S1-S9) and 5 controls positive for HBsAg (SWT.1-SWT.5) were analyzed. METHODS: Overlapping genome fragment amplification, cloning, and sequencing was performed on these cases. Functional analysis of surface promoter was conducted using fusion construct. RESULTS: All patients with occult infection except one (S8) had a low viral titer. Eight patients had infection with genotype A (S1-S5, SWT.1-2, SWT.5) and 6 had infection with genotype D (S6-S9, SWT.3-4). S4 and S5.1 of genotype A had the characteristic nucleotide deletions in core and pre-S1 region seen in genotype D. The major observations in patients with occult HBV infection were as follows: frequent quasispecies variation, deletions in pre-S2/S region affecting the surface promoters (nt 3025-54) and pre-S protein (S3, S5, S6, S8), truncated precore (S6, S8, S7.1) and core (S9) owing to stop signal, alternate start codon for the Polymerase gene (S3, S9), and YMDD mutation (S1, S4, S9) in patients not on antiviral therapy. HBsAg and core proteins could be shown immunohistochemically in 3 of 5 liver biopsy specimens available. The mutant surface promoters (pre-S2 and S) on functional analysis showed alterations in HBsAg expression. CONCLUSIONS: These changes in the regulatory region with possible alterations in the ratio of large and small surface proteins along with other mutations in the genome may decrease the circulating HBsAg level synergistically, making the immunodetection in serum negative.     

High-resolution single-photon emission computed tomography and X-ray computed tomography imaging of Tc-99m-labeled anti-DR5 antibody in breast tumor xenografts

A murine, apoptosis-inducing monoclonal antibody (mTRA-8) targeting human DR5 was radiolabeled with Tc-99m. The binding affinity (K(d)) and the number of DR5 receptors were measured in MD MBA-231-derived 2LMP cell lines that were "sensitive" or "resistant" to mTRA-8 killing. Single-photon emission computed tomography and X-ray computed tomography (SPECT/CT) evaluated the Tc-99m-mTRA-8 retention and distribution within xenograft tumors; biodistribution analyses confirmed the levels. Scatchard assays showed specific and high binding affinity of Tc-99m-mTRA-8 to DR5; the killing efficacy of mTRA-8 was unchanged by Tc-99m labeling. There was no significant difference between sensitive and resistant 2LMP cells for K(d) values (1.5 +/- 0.3 nmol/L = acid labile), or DR5 receptors (mean/cell = 11,000). SPECT/CT imaging analyses at 6 h after injection of Tc-99m-mTRA-8 revealed the second 1.5 mm shell from the surface of the mammary fat pad tumors (n = 5; 5,627 mm(3)) retained 12.7 +/- 1.4%ID/g, higher than the other shells, with no difference between the sensitive and resistant 2LMP tumors. Binding of Tc-99m-labeled mTRA-8 in tumor was specific; excess unlabeled mTRA-8 blocked Tc-99m-mTRA-8 retention in tumor by 45%. Retention of Tc-99m-labeled isotype antibody in tumor was consistent with the blocking study, and 30% lower. These studies show that SPECT/CT imaging provided detailed distribution information of Tc-99m-labeled mTRA-8 within breast tumor xenografts. Imaging could provide a mechanism to assess DR5 modulation when DR5 therapy is combined with chemotherapy and radiation, and thereby aid in optimizing the dosing schedule.