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result(s) for
"Johnson, Jennifer A"
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A noninteracting low-mass black hole–giant star binary system
by
Bieryla, Allyson
,
Covey, Kevin
,
Lindegren, Lennart
in
Astronomi, astrofysik och kosmologi
,
Astronomy, Astrophysics and Cosmology
,
Binary stars
2019
Black hole binary systems with companion stars are typically found via their x-ray emission, generated by interaction and accretion. Noninteracting binaries are expected to be plentiful in the Galaxy but must be observed using other methods. We combine radial velocity and photometric variability data to show that the bright, rapidly rotating giant star 2MASS J05215658+4359220 is in a binary system with a massive unseen companion. The system has an orbital period of ~83 days and near-zero eccentricity. The photometric variability period of the giant is consistent with the orbital period, indicating star spots and tidal synchronization. Constraints on the giant’s mass and radius imply that the unseen companion is
3.3
−
0.7
+
2.8
solar masses, indicating that it is a noninteracting low-mass black hole or an unexpectedly massive neutron star.
Journal Article
Populating the periodic table
2019
Elements heavier than helium are produced in the lives and deaths of stars. This Review discusses when and how the process of nucleosynthesis made elements. High-mass stars fuse elements much faster, fuse heavier nuclei, and die more catastrophically than low-mass stars. The explosions of high-mass stars as supernovae release elements into their surroundings. Supernovae can leave behind neutron stars, which may later merge to produce additional heavy elements. Dying low-mass stars throw off their enriched outer layers, leaving behind white dwarfs. These white dwarfs may also later merge and synthesize elements as well. Because these processes occur on different time scales and produce a different pattern of elements, the composition of the Universe changes over time as stars populate the periodic table.
Journal Article
Tecovirimat for the Treatment of Human Monkeypox: An Initial Series From Massachusetts, United States
2022
Abstract
A large, ongoing multicountry outbreak of human monkeypox has the potential to cause considerable morbidity and mortality. Therapeutics for the treatment of smallpox, a related Orthopoxvirus, may be used and affect the natural history of monkeypox. We present 3 patients from our hospitals treated with tecovirimat, a pan-Orthopoxvirus inhibitor currently available under an expanded access investigational new drug protocol for monkeypox.
Journal Article
Infective Endocarditis in the Pediatric Patient: A 60-Year Single-Institution Review
by
Johnson, Jennifer A.
,
Steckelberg, James M.
,
Boyce, Thomas G.
in
Adolescent
,
Anti-Bacterial Agents - therapeutic use
,
Antibiotic Prophylaxis
2012
To determine the epidemiology of infective endocarditis (IE) presenting in pediatric patients during a 60-year period at our institution.
In this retrospective medical record review, we extracted demographic characteristics, diagnostic variables, and outcomes for patients less than 20 years of age diagnosed with IE from January 1, 1980, to June 30, 2011. We compared this cohort with a previously reported cohort of pediatric patients with IE from our institution diagnosed from 1950 to 1979.
We identified 47 patients (24 males; mean ± SD age at diagnosis, 12.3±5.5 years [range, 1 day to 18.9 years]) who had 53 episodes of IE. The most common isolated organisms were viridans streptococci (17 of 53 episodes [32%]) and Staphylococcus aureus (12 of 53 episodes [23%]). Of the 47 patients, 36 (77%) had congenital heart disease, 24 of whom had cardiac surgery before their first episode of IE (mean ± SD time to IE diagnosis after surgery, 4.2±3.2 years [range, 64 days to 11.3 years]). Fourteen patients (30%) required valve replacement because of valvular IE, and 16 (34%) had complications, including mycotic aneurysm, myocardial abscess, or emboli. Vegetations were identified using echocardiography in 37 of the 53 unique episodes of IE (70%). Endocarditis-related mortality occurred in 1 patient. Compared with the historical (1950-1979) cohort, there were no differences in patient demographic characteristics, history of congenital heart disease, or infecting organisms. One-year mortality was significantly lower in the modern cohort (4%) compared with the historical cohort (38%) (P<.001).
Most pediatric episodes of IE occur in patients with congenital heart disease. Mortality due to endocarditis has decreased in the modern era.
Journal Article
ACE2 Improves Right Ventricular Function in a Pressure Overload Model
2011
Right ventricular (RV) dysfunction is a complication of pulmonary hypertension and portends a poor prognosis. Pharmacological therapies targeting RV function in pulmonary hypertension may reduce symptoms, improve hemodynamics, and potentially increase survival. We hypothesize that recombinant human angiotensin-converting enzyme 2 (rhACE2) will improve RV function in a pressure overload model.
rhACE2 administered at 1.8 mg/kg/day improved RV systolic and diastolic function in pulmonary artery banded mice as measured by in vivo hemodynamics. Specifically, rhACE2 increased RV ejection fraction and decreased RV end diastolic pressure and diastolic time constant (p<0.05). In addition, rhACE2 decreased RV hypertrophy as measured by RV/LV+S ratio (p<0.05). There were no significant negative effects of rhACE2 administration on LV function. rhACE2 had no significant effect on fibrosis as measured by trichrome staining and collagen1α1 expression. In pulmonary artery banded mice, rhACE2 increased Mas receptor expression and normalized connexin 37 expression.
In a mouse RV load-stress model of early heart failure, rhACE2 diminished RV hypertrophy and improved RV systolic and diastolic function in association with a marker of intercellular communication. rhACE2 may be a novel treatment for RV failure.
Journal Article
Pornography and the Male Sexual Script: An Analysis of Consumption and Sexual Relations
2016
Pornography has become a primary source of sexual education. At the same time, mainstream commercial pornography has coalesced around a relatively homogenous script involving violence and female degradation. Yet, little work has been done exploring the associations between pornography and dyadic sexual encounters: What role does pornography play inside real-world sexual encounters between a man and a woman? Cognitive script theory argues media scripts create a readily accessible heuristic model for decision-making. The more a user watches a particular media script, the more embedded those codes of behavior become in their worldview and the more likely they are to use those scripts to act upon real life experiences. We argue pornography creates a sexual script that then guides sexual experiences. To test this, we surveyed 487 college men (ages 18–29 years) in the United States to compare their rate of pornography use with sexual preferences and concerns. Results showed the more pornography a man watches, the more likely he was to use it during sex, request particular pornographic sex acts of his partner, deliberately conjure images of pornography during sex to maintain arousal, and have concerns over his own sexual performance and body image. Further, higher pornography use was negatively associated with enjoying sexually intimate behaviors with a partner. We conclude that pornography provides a powerful heuristic model which is implicated in men’s expectations and behaviors during sexual encounters.
Journal Article
Induction of HIV-1–Specific Mucosal Immune Responses Following Intramuscular Recombinant Adenovirus Serotype 26 HIV-1 Vaccination of Humans
by
Loblein, Hayley
,
Stachler, Matthew D.
,
Pau, Maria G.
in
Adenovirus
,
Adenoviruses, Human - immunology
,
Adult
2015
Background. Defining mucosal immune responses and inflammation to candidate human immunodeficiency virus type 1 (HIV-1) vaccines represents a current research priority for the HIV-1 vaccine field. In particular, it is unclear whether intramuscular immunization can elicit immune responses at mucosal surfaces in humans. Methods. In this double-blind, randomized, placebo-controlled clinical trial, we evaluated systemic and mucosal immune responses to a candidate adenovirus serotype 26 (Ad26) vectored HIV-1 envelop (Env) vaccine in baseline Ad26-seronegative and Ad26-seropositive healthy volunteers. Systematic mucosal sampling with rectal Weck-Cel sponges and rectal biopsies were performed. Results. Intramuscular immunization elicited both systemic and mucosal Env-specific humoral and cellular immune responses in the majority of subjects. Individuals with preexisting Ad26-specific neutralizing antibodies had vaccine-elicited immune responses comparable to those of subjects who were Ad26 seronegative. We also observed no increase in activated total or vector-specific mucosal CD4⁺ T lymphocytes following vaccination by either histopathology or flow cytometry. Conclusions. These data demonstrate that a single intramuscular administration of this Ad26-vectored HIV-1 Env vaccine elicited both systemic and mucosal immune responses in humans. Induction of antigen-specific humoral and cellular mucosal immunity was not accompanied by a detectable increase in mucosal inflammation.
Journal Article
Clinical factors associated with microstructural connectome related brain dysmaturation in term neonates with congenital heart disease
2022
Objective: Term congenital heart disease (CHD) neonates display abnormalities of brain structure and maturation, which are possibly related to underlying patient factors and perioperative insults. Our primary goal was to delineate associations between clinical factors and postnatal brain microstructure in term CHD neonates using diffusion tensor imaging (DTI) magnetic resonance (MR) acquisition combined with complementary data-driven connectome and seed-based tractography quantitative analysis. Our secondary goal was to delineate associations between mild dysplastic structural abnormalities and connectome and seed-base tractography as our primary goal. Methods: Neonates undergoing cardiac surgery for CHD were prospectively recruited from two large centers. Both pre- and postoperative magnetic resonance (MR) brain scans were obtained. DTI in 42 directions was segmented to 90 regions using neonatal brain template and three weighted methods. Seed- based tractography was performed in parallel. Clinical data :18 patient-specific and 9 preoperative variables associated with preoperative scan and 6 intraoperative and 12 postoperative variables associated with postoperative scan. A composite Brain Dysplasia Score (BDS) was created including cerebellar, olfactory bulbs, and hippocampus abnormalities. The outcomes included (1) connectome metrics: cost and global/nodal efficiency (2) seed-based tractography: fractional anisotropy. Statistics: multiple regression with false discovery rate correction (FDR). Results: A total of 133 term neonates with complex CHD were prospectively enrolled and 110 had analyzable DTI. Multiple patient-specific factors including d-transposition of the great arteries physiology and severity of impairment of fetal cerebral substrate delivery were predictive of preoperative reduced cost (p<0.0073), reduced global/nodal efficiency (p <0.03). Multiple postoperative factors (extracorporeal membrane oxygenation [ECMO], seizures, cardiopulmonary resuscitation) were predictive of postoperative reduced cost, reduced global/nodal efficiency (p < 0.05). All three subcortical structures of the BDS (including olfactory bulb/sulcus, cerebellum, and hippocampus) predicted distinct patterns of altered nodal efficiency (p<0.05). Conclusion: Patient-specific and postoperative clinical factors were most predictive of diffuse postnatal microstructural dysmaturation in term CHD neonates. In contrast, subcortical components of a structurally based- brain dysplasia score, predicted more regional based postnatal microstructural differences. Collectively, these findings suggest that brain DTI connectome may facilitate deciphering the mechanistic relative contribution of clinical and genetic risk factors related to poor neurodevelopmental outcomes in CHD.
Journal Article
Physiologic and molecular consequences of endothelial Bmpr2 mutation
by
Hagen, Moira
,
Stenmark, Kurt R
,
Gendron, Robert
in
Animals
,
Apoptosis
,
Bone Morphogenetic Protein Receptors, Type II - genetics
2011
Background
Pulmonary arterial hypertension (PAH) is thought to be driven by dysfunction of pulmonary vascular microendothelial cells (PMVEC). Most hereditary PAH is associated with BMPR2 mutations. However, the physiologic and molecular consequences of expression of BMPR2 mutations in PMVEC are unknown.
Methods
In vivo experiments were performed on adult mice with conditional endothelial-specific expression of the truncation mutation Bmpr2
delx4+
, with age-matched transactivator-only mice as controls. Phenotype was assessed by RVSP, counts of muscularized vessels and proliferating cells, and staining for thromboses, inflammatory cells, and apoptotic cells. The effects of BMPR2 knockdown in PMVEC by siRNA on rates of apoptosis were assessed. Affymetrix expression arrays were performed on PMVEC isolated and cultured from triple transgenic mice carrying the immortomouse gene, a transactivator, and either control, Bmpr2
delx4+
or Bmpr2
R899X
mutation.
Results
Transgenic mice showed increased RVSP and corresponding muscularization of small vessels, with histologic alterations including thrombosis, increased inflammatory cells, increased proliferating cells, and a moderate increase in apoptotic cells. Expression arrays showed alterations in specific pathways consistent with the histologic changes. Bmpr2
delx4+
and Bmpr2
R899X
mutations resulted in very similar alterations in proliferation, apoptosis, metabolism, and adhesion; Bmpr2
delx4+
cells showed upregulation of platelet adhesion genes and cytokines not seen in Bmpr2
R899X
PMVEC. Bmpr2 mutation in PMVEC does not cause a loss of differentiation markers as was seen with Bmpr2 mutation in smooth muscle cells.
Conclusions
Bmpr2 mutation in PMVEC
in vivo
may drive PAH through multiple, potentially independent, downstream mechanisms, including proliferation, apoptosis, inflammation, and thrombosis.
Journal Article
Gene Expression Ratios Lead to Accurate and Translatable Predictors of DR5 Agonism across Multiple Tumor Lineages
by
Monahan, John E.
,
Monaco, Kelli A.
,
Sellers, William R.
in
Animals
,
Anticancer properties
,
Antitumor agents
2015
Death Receptor 5 (DR5) agonists demonstrate anti-tumor activity in preclinical models but have yet to demonstrate robust clinical responses. A key limitation may be the lack of patient selection strategies to identify those most likely to respond to treatment. To overcome this limitation, we screened a DR5 agonist Nanobody across >600 cell lines representing 21 tumor lineages and assessed molecular features associated with response. High expression of DR5 and Casp8 were significantly associated with sensitivity, but their expression thresholds were difficult to translate due to low dynamic ranges. To address the translational challenge of establishing thresholds of gene expression, we developed a classifier based on ratios of genes that predicted response across lineages. The ratio classifier outperformed the DR5+Casp8 classifier, as well as standard approaches for feature selection and classification using genes, instead of ratios. This classifier was independently validated using 11 primary patient-derived pancreatic xenograft models showing perfect predictions as well as a striking linearity between prediction probability and anti-tumor response. A network analysis of the genes in the ratio classifier captured important biological relationships mediating drug response, specifically identifying key positive and negative regulators of DR5 mediated apoptosis, including DR5, CASP8, BID, cFLIP, XIAP and PEA15. Importantly, the ratio classifier shows translatability across gene expression platforms (from Affymetrix microarrays to RNA-seq) and across model systems (in vitro to in vivo). Our approach of using gene expression ratios presents a robust and novel method for constructing translatable biomarkers of compound response, which can also probe the underlying biology of treatment response.
Journal Article