Calcified left ventricular apical aneurysm with intramural thrombus: a case report.

Background: Left ventricular aneurysms (LVAs) are a well-appreciated complication of acute myocardial infarction. Ventricular aneurysms involving the left ventricle (LV) typically evolve as a result of anterior myocardial infarction and are associated with greater morbidity, complication rates, and hospital resource utilization. Incidence of LVA is decreasing with advent of modern reperfusion therapies; however, in the setting of excess morbidity, clinicians must maintain an appreciation for their appearance to allow timely diagnosis and individualized care. Case summary: This case report describes the clinical history, investigation, appearance, and management of a patient with calcified apical LVA with history of previous anterior ST-elevation myocardial infarction. The patient was initially admitted for elective coronary angiography in the setting of worsening exertional dyspnoea and subsequently underwent coronary artery bypass graft, aneurysm resection, and LV reconstruction. Discussion: Left ventricular aneurysms are an uncommon complication experienced in the modern era of acute myocardial infarction and current reperfusion therapies, but remain an important cause of excess morbidity and complication. Evidence-based guidelines for the diagnosis, workup, and subsequent management of LVAs are lacking. The imaging findings presented in this case serve as an important reminder of the appearance of LVAs so that timely diagnosis and individualized care considerations can be made.

The role of interoception in age-related obesity: A structural equation modelling study.

The obesity pandemic and its adverse effect on health and quality of life are well established. In younger populations, interoception and aberrant eating behaviour contribute to overconsumption and being overweight. Although the incidence of obesity is higher in older individuals, they remain under-researched in the obesity literature. Therefore, the present study considered the role of general (interoceptive sensibility) and appetite-specific (hunger drive and satiety responsiveness) interoception and obesogenic eating behaviour (food responsivity, emotional eating, enjoyment of eating) in the association between age and BMI. A total of 1006 female adults (aged 18 to 80) completed the Adult Eating Behaviour Questionnaire and the Interoceptive Attention and Accuracy scales. Structural Equation Modelling (SEM) in AMOS was used to explore the data for multiple serial mediation effects. Despite being more overweight, older adults reported lower interoceptive attention, hunger drive, emotional overeating, food responsivity, and enjoyment of food. In contrast, compared to younger adults, older adults reported a higher interoceptive accuracy, and a similar responsivity to satiety. Importantly, two indirect pathways positively mediated the link between age and BMI: (1) age ➤(-)➤ interoceptive attention ➤(+)➤ satiety responsivity ➤(-)➤ emotional eating ➤(+)➤ BMI and (2) age ➤(-)➤ interoceptive attention ➤(+)➤ satiety responsivity ➤(-)➤ food responsivity ➤(+)➤ BMI. However, a stronger antagonistic indirect pathway was also present: age ➤(-)➤ interoceptive attention ➤(+)➤ hunger drive ➤(+)➤ emotional eating ➤(+)➤ BMI. The present findings suggested that overall reduced interoceptive attention in older adults may protect against weight gain by lowering hunger and the propensity towards obesogenic eating behaviours. These findings have implications for the design of appetite interventions in older populations.

Pericardial decompression syndrome with acute right ventricular failure: a case series.

Background: Pericardial decompression syndrome (PDS) is an uncommon complication of pericardial drainage of large pericardial effusions and cardiac tamponade characterized by paradoxical haemodynamic instability following drainage. Pericardial decompression syndrome may occur immediately, or in the days following pericardial decompression, and presents with signs and symptoms suggestive of uni-/biventricular failure or acute pulmonary oedema. Case summary: This series describes two cases of this syndrome which demonstrates acute right ventricular failure as a mechanism of PDS and provides insights into the echocardiographic findings and clinical course of this poorly understood syndrome. Case 1 describes a patient who underwent pericardiocentesis, whilst Case 2 describes a patient who underwent surgical pericardiostomy. In both patients, acute right ventricular failure was observed following the release of tamponade and is favoured to be the cause of haemodynamic instability. Discussion: Pericardial decompression syndrome is a poorly understood, likely underreported complication of pericardial drainage for cardiac tamponade associated with high morbidity and mortality. Whilst a number of hypotheses exist as to the aetiology of PDS, this case series supports haemodynamic compromise being secondary to left ventricular compression following acute right ventricular dilatation.

Concurrent left ventricular and left anterior coronary artery thrombus: is COVID-19 an innocent bystander?

We present the angiographic findings of a case of myocardial infarction associated with COVID-19 with a heavy burden of thrombus, despite only minor obstructive coronary disease.

Carbohydrate and sleep: An evaluation of putative mechanisms.

Sleep problems are extremely common in industrialized countries and the possibility that diet might be used to improve sleep has been considered. The topic has been reviewed many times, resulting in the frequent suggestion that carbohydrate increases the uptake of tryptophan by the brain, where it is metabolized into serotonin and melatonin, with the suggestion that this improves sleep. An alternative mechanism was proposed based on animal literature that has been largely ignored by those considering diet and sleep. The hypothesis was that, as in the hypothalamus there are glucose-sensing neurons associated with the sleep-wake cycle, we should consider the impact of carbohydrate-induced changes in the level of blood glucose. A meta-analysis found that after consuming a lower amount of carbohydrate, more time was spent in slow-wave sleep (SWS) and less in rapid-eye-movement sleep. As the credibility of alternative mechanisms has tended not to have been critically evaluated, they were considered by examining their biochemical, nutritional, and pharmacological plausibility. Although high carbohydrate consumption can increase the uptake of tryptophan by the brain, it only occurs with such low levels of protein that the mechanism is not relevant to a normal diet. After entering the brain tryptophan is converted to serotonin, a neurotransmitter known to influence so many different aspects of sleep and wakefulness, that it is not reasonable to expect a uniform improvement in sleep. Some serotonin is converted to melatonin, although the exogenous dose of melatonin needed to influence sleep cannot be credibly provided by the diet. This review was registered in the International Prospective Register of Systematic Reviews (CRD42020223560).

Weaker connectivity in resting state networks is associated with disinhibited eating in older adults.

BACKGROUND/OBJECTIVES: Obesity affects more than forty percent of adults over the age of sixty. Aberrant eating styles such as disinhibition have been associated with the engagement of brain networks underlying executive functioning, attentional control, and interoception. However, these effects have been exclusively studied in young samples overlooking those most at risk of obesity related harm. METHODS: Here we assessed associations between resting-state functional connectivity and disinhibited eating (using the Three Factor Eating Questionnaire) in twenty-one younger (aged 19-34 years, BMI range: 18-31) and twenty older (aged 60-73 years, BMI range: 19-32) adults matched for BMI. The Alternative Healthy Eating Index was used to quantify diet quality. RESULTS: Older, compared to younger, individuals reported lower levels of disinhibited eating, consumed a healthier diet, and had weaker connectivity in the frontoparietal (FPN) and default mode (DMN) networks. In addition, associations between functional connectivity and eating behaviour differed between the two age groups. In older adults, disinhibited eating was associated with weaker connectivity in the FPN and DMN--effects that were absent in the younger sample. Importantly, these effects could not be explained by differences in habitual diet. CONCLUSIONS: These findings point to a change in interoceptive signalling as part of the ageing process, which may contribute to behavioural changes in energy intake, and highlight the importance of studying this under researched population.

The SEEKING Drive and Its Fixation: A Neuro-Psycho-Evolutionary Approach to the Pathology of Addiction.

Neuro-ethological studies conducted by Panksepp and his colleagues have provided an understanding of how the activity of the mesolimbic dopaminergic (ML DA) system leads to the emotional disposition to SEEK/Explore, which is involved in all appetitive motivated behavior and mental activity. In pathological addiction phenomena, this emotional disposition "fixes" itself on certain obsessive-compulsive habits, losing its versatility and its natural predisposition to spontaneous and unconditioned activation. Overall, the result is a consistent disinterest in everything that is not the object of addiction. From a neuro-psycho-evolutionary point of view, the predisposition to develop addictive behavior can be attributed to a loss of "functional autonomy" of the SEEKING/Explorative disposition. Indeed, as shown by animal and human studies, the tendency to be conditioned by situations and contexts that provide an immediate reward can be closely related to a deficit in the tonic endogenous activity of the ML DA-SEEKING system.

Comparative analysis of two isocyanate-free urethane-based gels for antifouling applications.

Amphiphilic gels consisting of acrylamide (AAM)/2-hydroxyethyl methacrylate (HEMA), hexafluorobutyl methacrylate (HFBMA) and non-isocyanate urethane dimethacrylate (NIUDMA) of varying molecular weights were compared. A three-level Taguchi analysis was performed using the amount of AAM/HEMA, HFBMA, NIUDMA and reaction time as dependent variables to determine the optimal formulation of the gels with maximized toughness and elastic modulus. The results were compared with commercial AF/FR Intersleek® coatings (IS 700, IS 900 and IS 1100SR) for their antifouling performance against a marine microalga (Navicula incerta), a marine bacterium (Cellulophaga lytica) and adult barnacles (Amphibalanus amphitrite). The toughness, elastic modulus and strain at break of the optimized AAM gels ranged from 3 to7 MPa, 25 to 72 MPa and 80% to 170%, respectively, whereas those of the optimized HEMA gels ranged from 1 to 3 MPa, 13 to 23 MPa and 76% to 160%, respectively. The gels, particularly AHN(E9) and HHN(E12), showed reductions of attachment compared with IS700 of up to 93% and 58%, respectively.

Tough amphiphilic antifouling coating based on acrylamide, fluoromethacrylate and non-isocyanate urethane dimethacrylate crosslinker.

This study is focused on the development of tougher gels using combinations of acrylamide, fluoromethacrylate and a non-isocyanate urethane dimethacrylate (NIUDMA) crosslinker. The NIUDMA was tailored with 2, 3-epoxypropoxy propyl-polydimethylsiloxane segments E9 (MW = 0.36 kg mol-1), E11 (MW = 0.5-0.6 kg mol-1) and E12 (MW = 1-1.4 kg mol-1). A 3 level Taguchi design was used to evaluate the role of each component of the ternary copolymer gel on the elastic modulus and toughness. The toughness ranged from 2.5-7 MJ m-3 whereas the modulus ranged from 27-70 MPa. The formulations with the highest toughness and modulus were screened for their antifouling potential in biological assays against the microalga Navicula incerta and the bacterium Cellulophaga lytica. The E9 gels showed the best performance, achieving a 73% reduction in N. incerta cells and a 92% reduction in C. lytica biofilm remaining after water jetting treatments, when compared with the commercial Intersleek product IS700.

Anti-biofouling properties of poly(dimethyl siloxane) with RAFT photopolymerized acrylate/methacrylate surface grafts against model marine organisms.

Biofouling of man-made surfaces by marine organisms is a global problem with both financial and environmental consequences. However, the development of non-toxic anti-biofouling coatings is challenged by the diversity of fouling organisms. One possible solution leverages coatings composed of diverse chemical constituents. Reversible addition-fragmentation chain-transfer (RAFT) photopolymerization was used to modify poly(dimethylsiloxane) (PDMSe) surfaces with polymeric grafts composed of three successive combinations of acrylamide, acrylic acid, and hydroxyethyl methacrylate. RAFT limited conflicting variables and allowed for the effect of graft chemistry to be isolated. While all compositions enhanced the anti-biofouling performance compared with the PDMSe control, the ternary, amphiphilic copolymer was the most effective with 98% inhibition of the attachment of zoospores of the green alga Ulva linza, 94% removal of cells of the diatom Navicula incerta, and 62% removal of cells of the bacterium Cellulophaga lytica. However, none of the graft compositions tested were able to mitigate reattachment of adult barnacles, Amphibalanus amphitrite.

Microtopographical patterns promote different responses in fibroblasts and Schwann cells: A possible feature for neural implants.

The chronic reliability of bioelectronic neural interfaces has been challenged by foreign body reactions (FBRs) resulting in fibrotic encapsulation and poor integration with neural tissue. Engineered microtopographies could alleviate these challenges by manipulating cellular responses to the implanted device. Parallel microchannels have been shown to modulate neuronal cell alignment and axonal growth, and Sharklet™ microtopographies of targeted feature sizes can modulate bio-adhesion of an array of bacteria, marine organisms, and epithelial cells due to their unique geometry. We hypothesized that a Sharklet™ micropattern could be identified that inhibited fibroblasts partially responsible for FBR while promoting Schwann cell proliferation and alignment. in vitro cell assays were used to screen the effect of Sharklet™ and channel micropatterns of varying dimensions from 2 to 20 µm on fibroblast and Schwann cell metrics (e.g., morphology/alignment, nuclei count, metabolic activity), and a hierarchical analysis of variance was used to compare treatments. In general, Schwann cells were found to be more metabolically active and aligned than fibroblasts when compared between the same pattern. 20 µm wide channels spaced 2 µm apart were found to promote Schwann cell attachment and alignment while simultaneously inhibiting fibroblasts and warrant further in vivo study on neural interface devices. No statistically significant trends between cellular responses and geometrical parameters were identified because mammalian cells can change their morphology dependent on their environment in a manner dissimilar to bacteria. Our results showed although surface patterning is a strong physical tool for modulating cell behavior, responses to micropatterns are highly dependent on the cell type.

Surface texture limits transfer of S. aureus, T4 bacteriophage, influenza B virus and human coronavirus.

Spread of pathogens on contaminated surfaces plays a key role in disease transmission. Surface technologies that control pathogen transfer can help control fomite transmission and are of great interest to public health. Here, we report a novel bead transfer method for evaluating fomite transmission in common laboratory settings. We show that this method meets several important criteria for quantitative test methods, including reasonableness, relevancy, resemblance, responsiveness, and repeatability, and therefore may be adaptable for standardization. In addition, this method can be applied to a wide variety of pathogens including bacteria, phage, and human viruses. Using the bead transfer method, we demonstrate that an engineered micropattern limits transfer of Staphylococcus aureus by 97.8% and T4 bacteriophage by 93.0% on silicone surfaces. Furthermore, the micropattern significantly reduces transfer of influenza B virus and human coronavirus on silicone and polypropylene surfaces. Our results highlight the potential of using surface texture as a valuable new strategy in combating infectious diseases.

An Unusual Case of Shock Following an Elective Caesarean Delivery.

BACKGROUND: The differential diagnosis of peripartum chest pain and cardiogenic shock is broad and includes pulmonary embolism, amniotic fluid embolism, peripartum and Takotsubo cardiomyopathy, myocardial infarction, and anaesthetic complications. CASE: A 31-year-old woman with Addison's disease underwent an elective caesarean section that was complicated by chest pain and cardiogenic shock. After initial resuscitation, she was transferred to a tertiary hospital, and urgent transthoracic echocardiography revealed severe systolic dysfunction. She was treated with an increased dose of hydrocortisone and intravenous furosemide and improved. Follow-up imaging showed improvement of left ventricular systolic function. CONCLUSION: In patients with cardiogenic shock after delivery, early transthoracic echocardiography is a non-invasive tool that can rapidly narrow the differential diagnosis.

Engineered Chemical Nanotopographies: Reversible Addition-Fragmentation Chain-Transfer Mediated Grafting of Anisotropic Poly(acrylamide) Patterns on Poly(dimethylsiloxane) To Modulate Marine Biofouling.

Effectively negating the deleterious impact of marine biofouling on the world's maritime fleet in an environmentally conscientious manner presents a difficult challenge due to a variety of factors including the complexity and diversity of fouling species and the differing surface adhesion strategies. Understanding how surface properties relate to biofouling can inform and guide the development of new antibiofouling coatings to address this challenge. Herein, we report on the development of a living photopolymerization strategy used to tailor the surface properties of silicone rubber using controlled anisotropic poly(acrylamide) patterns and the resulting antibiofouling efficacy of these surfaces against zoospores of the model marine fouling organism, Ulva linza. Chemical patterns were fabricated using reversible addition-fragmentation chain-transfer (RAFT) living polymerization in conjunction with photolithography. Pattern geometries were inspired by the physical (i.e., nonchemical) Sharklet engineered microtopography system that has been shown to be effective against the same model organism. Sharklet chemical patterns and analogous parallel channels were fabricated in sizes ranging from 2 to 10 µm in the lateral dimension with tailorable feature heights ranging from tens to hundreds of nanometers. Nonpatterned, chemically grafted poly(acrylamide) silicone surfaces inhibited algal spore attachment density by 59% compared to the silicone control; however, attachment density on chemical nanotopographies was not statistically different from the control. While these results indicate that the chemical nanotopographies chosen do not represent an effective antibiofouling coating, it was found that the Sharklet pattern geometry, when sized below the 5 µm critical attachment size of the spores, significantly reduced the algal spore density compared to the equally sized channel geometry. These results indicate that specific chemical geometry of the proper sizing can impact the behavior of the algal spores and could be used to further study the mechanistic behavior of biofouling organisms.

Patency When Grafted to Coronary Stenosis More Than 50% in LIMA-RA-Y Grafts.

BACKGROUND: Recent coronary surgery practice is to graft arterial conduits to more severely stenosed coronary targets than in the past. We aimed to investigate postoperative arterial graft patency with native coronary stenosis at the time of surgery, using the left internal mammary artery and radial artery (RA) as a composite Y graft (LIMA-RA-Y). In the study timeframe, it was routine clinical practice to graft coronary arteries with >50% stenosis. METHODS: Of 464 patients previously reported 1996-1999, 346 who underwent LIMA-RA-Y at the Royal Melbourne Hospital, 76 had postoperative angiograms at the same institution. Each anastomosis was considered separately. For arterial grafts a "string sign" was analysed as being occluded. Predictor of patency was performed with a generalised linear mixed model (GLMM). RESULTS: Seventy-six (76) patients had postoperative angiograms at 5.8±5.4 years (range 0.23-19.4; interquartile range 1.7-10.0) years postoperative; with age at operation 62.5±10.7 years and 3.4±0.8 grafts per patient, 82% were male. Of 256 anastomoses, 230 were to coronary targets >50% stenosis. Overall patency was 84.0% (214/256). For coronary stenosis >50%, patency was 88% (201/230) and varied by coronary territory left anterior descending (LAD) 94% (87/93), circumflex 90% (71/79) and right coronary artery (RCA) 74% (43/58). Interaction for coronary territory was significant (p=0.022). Higher preoperative coronary stenosis predicted higher patency; with odds ratio for improved patency of 1.83 (95% CI 1.51, 2.22), p<0.001 for each 10% increase in stenosis. CONCLUSIONS: Late patency of composite arterial grafts is acceptable when grafted to coronary arteries of greater than 50% stenosis.

Effects of inter-organism interactions in biofouling on microtopographic surfaces.

An extended model of the surface energetic attachment (SEA) model is introduced to study the fouling of marine organisms on microtopographic surfaces, taking into account the excluded volume interaction and the attraction between the organisms. It is shown that the excluded volume interaction leads to changes in the site-typed attachment probabilities which increase with the average spore density on the surface. As a result of these changes, the spore density map is flattened under very high density fouling. The attractive interaction on the other hand leads to aggregation of spores and the average aggregate size increased with the strength of attraction. The model can be mapped to a specific experiment to determine the attachment energy parameters. In contrast to various prior empirical approaches, the extended SEA model is rigorous from the statistical mechanics viewpoint, thus it provides a reliable tool for studying complex attachment behaviors of microorganisms on topographic surfaces.

Impact of the Cox-Maze IV Procedure on Left Atrial Mechanical Function.

BACKGROUND: The Cox-Maze IV procedure is a proven surgical treatment for atrial fibrillation (AF). Previous studies on the procedure and its effect on left atrial mechanical function have yielded mixed results. METHODS: Sixty-four (64) patients underwent Cox-Maze IV at St Vincent's Hospital, Melbourne between March 2010 and May 2016. Baseline characteristics were collected and outcomes assessed including rhythm analysis. Preoperative and postoperative transthoracic echocardiograms were reviewed. RESULTS: Fifty-seven (57) patients had complete follow-up with all clinical measures collected. The mean age was 71.1±10.2years, 63% being male. Fifty-eight per cent (58%) (33/57) of patients were in AF and 42% (24/57) in sinus rhythm (SR) at preoperative transthoracic echocardiography. Follow-up postoperative transthoracic echocardiography was performed at a mean of 2.3±1.9years. Nineteen (19) patients with a history of paroxysmal AF were in SR both preoperatively and postoperatively. In these patients, there was a significant decrease in Mitral A wave 0.63±0.28m/s (pre-op) vs 0.47±0.29m/s (post-op), p=0.044. There was a significant decrease in left ventricular ejection fraction (LVEF) postoperatively 64.2±9.7% vs 55.0±12.9%, p=0.005. At follow-up, 28% (16/57) were in AF, 61% (35/57) in SR, and 11% (6/57) in a paced rhythm. In a multivariate analysis, predictors of AF recurrence included higher LA volumes (p=0.042) and younger age at surgery p=0.030. Preoperative AF, sex and LVEF had no impact on AF recurrence. CONCLUSIONS: The Cox-Maze IV procedure, while effective in converting patients to sinus rhythm, may reduce left atrial mechanical function in patients with paroxysmal AF.