The influence of differing pore sizes on the biocompatibility of two polypropylene meshes in the repair of abdominal defects. Experimental study in dogs

Two types of monofilament polypropylene meshes of markedly different construction, configuration and pore size were compared and used to repair full-thickness muscle defects in the abdominal wall of 22 mongrel dogs to assess their biocompatibility with host tissues. The defects were repaired with Prolene (Ethicon) woven mesh (pore size = 164 x 96 microns) and with an experimental, extruded mesh called T mesh (pore size = 3 mm x 4 mm). On the 30th postoperative day, the animals were sacrificed, and the segments of the abdominal wall containing the implanted meshes were excised. Although the Prolene mesh had greater tensile strength before implantation, 30 days after implantation, the T mesh showed similar tensile strength to Prolene mesh. The collagen densitometry showed a significant increase of total and mature collagen type I deposition in the T mesh. This suggests that the increased mature collagen type I deposition significantly increases the tensile strength of the reinforced mesh tissue and that the larger pore in the T mesh contributed to this finding by allowing increasing fibber orientation within the pores as a result of in vivo tension.

Effect of spironolactone on ventricular arrhythmias in congestive heart failure secondary to idiopathic dilated or to ischemic cardiomyopathy

Epidemiologic studies have shown an important increase in the high mortality of patients with congestive heart failure (CHF) despite optimal medical management. Ventricular arrhythmia was recognized as the most common cause of death in this population. Electrolyte imbalance, myocardial fibrosis, left ventricular dysfunction, and inappropriate neurohumoral activation are presumed responsible for sudden cardiac death. In this study, we focused on the deleterious effects of the overproduction of aldosterone that occurs in patients with CHF. Secondary hyperaldersteronism can be part of several factors thought to be responsible for sudden cardiac death. We randomized 35 patients (32 men, aged 48 +/- 9 years) with systolic dysfunction (ejection fraction 33 +/- 5%) and New York Heart Association class III CHF secondary to dilated or ischemic cardiomyopathy into 2 groups. The treatment group received spironolactone, an aldosterone receptor antagonist, along with standard medical management using furosemide, angiotensin-converting enzyme inhibitors, and digoxin. The control group received only the standard medical treatment. Holter monitoring was used to assess the severity of ventricular arrhythmia. After 20 weeks, patients who received spironolactone had a reduced hourly frequency of ventricular premature complexes (VPCs) (65 +/- 18 VPCs/hour at week 0 and 17 +/- 9 VPCs/hour at week 16) and episodes of nonsustained ventricular tachycardia (VT) (3.0 +/- 0.8 episodes of VT/24-hour period at week 0, and 0.6 +/- 0.3 VT/24-hour period at week 16). During monitored treadmill exercise, a significant improvement in ventricular arrhythmia was found in the group receiving spironolactone (39 +/- 10 VPCs at week 0, and 6 +/- 2 VPCs at week 16). These findings suggest that aldosterone may contribute to the incidence of ventricular arrhythmia in patients with CHF, and spironolactone helps reduce this complication.

One-step colloidal synthesis of biocompatible water-soluble ZnS quantum dot/chitosan nanoconjugates

Quantum dots (QDs) are luminescent semiconductor nanocrystals with great prospective for use in biomedical and environmental applications. Nonetheless, eliminating the potential cytotoxicity of the QDs made with heavy metals is still a challenge facing the research community. Thus, the aim of this work was to develop a novel facile route for synthesising biocompatible QDs employing carbohydrate ligands in aqueous colloidal chemistry with optical properties tuned by pH. The synthesis of ZnS QDs capped by chitosan was performed using a single-step aqueous colloidal process at room temperature. The nanobioconjugates were extensively characterised by several techniques, and the results demonstrated that the average size of ZnS nanocrystals and their fluorescent properties were influenced by the pH during the synthesis. Hence, novel 'cadmium-free' biofunctionalised systems based on ZnS QDs capped by chitosan were successfully developed exhibiting luminescent activity that may be used in a large number of possible applications, such as probes in biology, medicine and pharmacy.

Enzyme-polymers conjugated to quantum-dots for sensing applications

In the present research, the concept of developing a novel system based on polymer-enzyme macromolecules was tested by coupling carboxylic acid functionalized poly(vinyl alcohol) (PVA-COOH) to glucose oxidase (GOx) followed by the bioconjugation with CdS quantum-dots (QD). The resulting organic-inorganic nanohybrids were characterized by UV-visible spectroscopy, infrared spectroscopy, Photoluminescence spectroscopy (PL) and transmission electron microscopy (TEM). The spectroscopy results have clearly shown that the polymer-enzyme macromolecules (PVA-COOH/GOx) were synthesized by the proposed zero-length linker route. Moreover, they have performed as successful capping agents for the nucleation and constrained growth of CdS quantum-dots via aqueous colloidal chemistry. The TEM images associated with the optical absorption results have indicated the formation of CdS nanocrystals with estimated diameters of about 3.0 nm. The "blue-shift" in the visible absorption spectra and the PL values have provided strong evidence that the fluorescent CdS nanoparticles were produced in the quantum-size confinement regime. Finally, the hybrid system was biochemically assayed by injecting the glucose substrate and detecting the formation of peroxide with the enzyme horseradish peroxidase (HRP). Thus, the polymer-enzyme-QD hybrid has behaved as a nanostructured sensor for glucose detecting.

Surface biofunctionalized CdS and ZnS quantum dot nanoconjugates for nanomedicine and oncology: to be or not to be nanotoxic?

Herein, for the first time, we demonstrated that novel biofunctionalized semiconductor nanomaterials made of Cd-containing fluorescent quantum dot nanoconjugates with the surface capped by an aminopolysaccharide are not biologically safe for clinical applications. Conversely, the ZnS-based nanoconjugates proved to be noncytotoxic, considering all the parameters investigated. The results of in vitro cytotoxicity were remarkably dependent on the chemical composition of quantum dot (CdS or ZnS), the nature of the cell (human cancerous and embryonic types), and the concentration and time period of exposure to these nanomaterials, caused by the effects of Cd2+ on the complex nanotoxicity pathways involved in cellular uptake. Unexpectedly, no decisive evidence of nanotoxicity of CdS and ZnS conjugates was observed in vivo using intravenous injections in BALB/c mice for 30 days, with minor localized fluorescence detected in liver tissue specimens. Therefore, these results proved that CdS nanoconjugates could pose an excessive threat for clinical applications due to unpredicted and uncorrelated in vitro and in vivo responses caused by highly toxic cadmium ions at biointerfaces. On the contrary, ZnS nanoconjugates proved that the "safe by design" concept used in this research (ie, biocompatible core-shell nanostructures) could benefit a plethora of applications in nanomedicine and oncology.

Quantum dot/glycol chitosan fluorescent nanoconjugates

In this study, novel carbohydrate-based nanoconjugates combining chemically modified chitosan with semiconductor quantum dots (QDs) were designed and synthesised via single-step aqueous route at room temperature. Glycol chitosan (G-CHI) was used as the capping ligand aiming to improve the water solubility of the nanoconjugates to produce stable and biocompatible colloidal systems. UV-visible (UV-vis) spectroscopy, photoluminescence (PL) spectroscopy, and Fourier transform infrared (FTIR) spectroscopy were used to characterise the synthesis and the relative stability of biopolymer-capped semiconductor nanocrystals. The results clearly demonstrated that the glycol chitosan derivative was remarkably effective at nucleating and stabilising semiconductor CdS quantum dots in aqueous suspensions under acidic, neutral, and alkaline media with an average size of approximately 2.5 nm and a fluorescent activity in the visible range of the spectra.

Recycled collagen films as biomaterials for controlled drug delivery

Recyclable collagen is a potential candidate to be used as development prototypes in biomaterial scientific research.

Nitric oxide production and apoptosis by GP120

Nitric oxide (NO) is increased by gp120 in astrocytes and in monocyte-derived macrophages. Of the gp120 fragments (F1: amino acid 254-274, F2: amino acid 315-329, F3: amino acid 421-438), F1 has been shown to increase NO in astrocytes and gp120 also primes CD4+ T cells for apoptosis. Peripheral blood mononuclear cells (PBMCs) at 10(6)/ml (N = 10) were incubated at 24 and 72 hours in RPMI, 10% CO2 with low doses (100 nM) gp120 and high doses (400 nM) of the smaller fragments. Supernatants were collected and assayed for the relative contribution of gp120 and its fragments on NO production at both time points. Apoptosis was detected by in situ hybridization with and without 1 microgram/ml LPS as superantigen at 72 hours. The major contribution to apoptosis and NO production was from F1. At 24 hours F1 had a 1.9-fold increase from control, whereas F2 and F3 had 1.25- and 1.35-fold increases. At 72 hours both F1 and F2 had a 1.5-fold increase and F3 had a 1.33 increase. Thus, F1 contributed significantly to NO production at 24 hours. Both F1 and F2 had significant contributions to NO production at 72 hours. F1 had the most contribution to apoptosis both with and without lipopolysaccharide (LPS). These findings may contribute to further understanding the mechanism of HIV-induced apoptosis.

Reversibility of small airway obstruction after therapy with salbutamol. Studies in asymptomatic asthmatic patients after inhalation of pressurized aerosol

A group of 18 asymptomatic asthmatic patients and a control group of five healthy individuals were examined in order to evaluate the effect of inhalation of 400 microng of salbutamol on the small airways. All patients were free of symptoms for at least three days before the investigation. On the day of investigation, total lung resistance, static lung compliance, and dynamic compliance at a respiratory frequency of 60 breaths per minute (Cdyn60) were measured. While no change in Cdyn60 occurred in the control group, a statistically significant decrease in Cdyn60 was found before inhalation of salbutamol in all 18 asthmatic patients (P less than 0.005), indicating obstruction of small airways. After inhalation of 400microng of salbutamol, a significant increase in Cdyn60 occurred (P less than 0.005), starting five minutes after inhalation and lasting over one hour, indicating an almost complete abolishment of the frequency dependence of lung compliance in these patients. The present findings indicate that sulbutamol aerosol has a potent bronchodilator effect on the large, as well as the small, airways in the early stage of recovery following an acute asthmatic attack.

Prevalence of abnormalities on cardiac MRI in unselected patients after recovery from acute SARS-CoV-2 infection and correlation with markers of immunity and coagulation: the SETANTA study

Background

Previous studies have reported ongoing cardiac inflammation as assessed by cardiac magnetic resonance imaging (CMR) in a significant proportion of patients several months after recovery from SARS-CoV-2 infection, many of whom had no or minimal symptoms at the time of infection.

Purpose

The aim of SETANTA was to investigate the prevalence of cardiac abnormalities by CMR in unselected patients in Ireland after acute SARS-CoV-2 infection and the correlation with immunological response and biomarkers of coagulation.

Methods

This was a prospective, observational, community-based study (clinicaltrials.gov identifier NCT04823182). Consecutive patients recovered from recent SARS-CoV-2 infection at 3 primary care sites were invited to participate. Key inclusion/exclusion criteria and outcomes of interest are shown in Figure 1.

Results

100 participants were enrolled (Feb-Sept 2021) at a median of 188 (IQR, 125, 246) days after positive SARS-CoV-2 swab. At index infection, 18% and 35% reported severe and moderate symptoms, respectively; 14% were hospitalized; 3% were admitted to intensive care for ventilatory support. At enrolment, 83% had ongoing symptoms. 85% had detectable SARS-CoV-2 antigens. CMR and laboratory findings are shown in Figure 1.

Conclusion

Among an unselected cohort of patients recovered from acute SARS-CoV2 infection, we report a low prevalence of cardiac abnormalities by CMR, despite a high prevalence of moderate/severe symptoms at presentation and a high prevalence of persistent symptoms. Correlation with biomarkers of immunity and coagulation will be available at ESC 2022.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): WomenAsOne

[Left bundle branch block analysis by body surface mapping. Comparison with electrocardiographic and vectocardiographic findings]

PURPOSE

To compare the correlation between the departure areas (DA), negative or positive, in patients whose electrocardiogram showed left bundle branch block (LBBB) and association with left ventricular hipertrophy (LVH) and myocardial infarction (MI), to the electrocardiographic (ECG) and vectocardiographic (VCG) classic criteria.

METHODS

The study was carried out with 46 patients (27 males) with LBBB. These patients had hypertension (19.5%), coronary heart disease (34.7%) and 21 patients with no heart disease (45.8%).

RESULTS

The statistic analysis using the Cluster method divided the patients in two groups. Group I (22 patients) showed an average rate for the DA (-2 SD) of 1091 for QRS and of 640 for ST-T. For the DA (+2 SD), the average rate was 618 for QRS and 881 for ST-T; group II (24 patients) showed an averaged for the DA (-2 SD) of 1063 for QRS and of 225 for ST-T. For the DA (+2 SD), the averaged rate was 428 for QRS and 600 for ST-T.

CONCLUSION

In general the current ECG/VCG findings, can not differentiate the presence of the association of LBBB to LVH and MI. The DA of ST-T, mainly negative was the most efficient to separate the two groups and help in the differential diagnosis.

Prognostic implications of transient left ventricular cavitary dilation during exercise and dipyridamole-thallium imaging

OBJECTIVE

To determine the prognostic implication of exercise and dipyridamole-induced transient left ventricular cavitary dilation (TLVD).

DESIGN

TLVD was observed and a follow-up obtained in 61 patients after exercise and in 62 patients following dipyridamole infusion.

PATIENTS

There was no statistical difference between groups in terms of sex, history of hypertension, diabetes, renal failure, previous myocardial infarction, severity of angina syndrome, congestive heart failure, resting electrocardiographic (ECG) abnormalities, clinical or ECG signs of ischemia during stress, number of reversible perfusion defects on thallium images or duration of follow-up (21 months).

RESULTS

Dipyridamole patients were slightly older (64 versus 57 years) and displayed more thallium redistribution (P = 0.002). After a mean follow-up of 21 months, both fatal and nonfatal (myocardial infarction or cardiac death) cardiac events were more frequent in the dipyridamole group (50% versus 9%, P = 0.0001).

CONCLUSIONS

Patients with dipyridamole-induced TLVD are at greater risk than those with exercise-induced TLVD at the authors' institution.

Mid-term results of heart transplantation, cardiomyoplasty, and medical treatment of refractory heart failure caused by idiopathic dilated cardiomyopathy

BACKGROUND

Heart transplantation is the surgical procedure of choice for treatment of refractory heart failure. However, it benefits a small number of patients because of the limited number of donors and selection criteria of recipients. Cardiomyoplasty is an alternative surgical procedure for heart failure. The aim of this investigation was to report our experience with heart transplantation, cardiomyoplasty, and clinical treatment of heart failure caused by idiopathic dilated cardiomyopathy.

METHODS

Ninety patients with refractory heart failure caused by idiopathic dilated cardiomyopathy were observed from May 1988 to March 1993. The patients had New York Heart Association functional class III or IV symptoms. The patients were divided in three groups according to the treatment received: heart transplantation (33 patients), cardiomyoplasty (25 patients), or medical treatment (32 patients). We studied the event-free curve, the New York Heart Association functional class, the left ventricular ejection fraction, and the morbidity of the groups in the follow-up of 19 +/- 16 months. We considered as an event death or crossover to another group because of severe symptoms.

RESULTS

The event-free rate in the cardiomyoplasty group was 92%, 88%, 79%, 74%, and 62% at 3, 9, 12, 18, and 24 months of follow-up, respectively. The event-free rate after heart transplantation was 82%, 78%, 82%, 75%, and 69% at 3, 9, 12, 18, and 24 months, respectively. The event-free rate in the medical treatment group was 78%, 65%, 61%, 48%, and 48% at 3, 9, 12, 18, and 24 months, respectively. All surviving patients in the heart transplantation group had functional class I symptoms. After cardiomyoplasty 90% of surviving patients had class I or II symptoms and 10% had class III symptoms. However, in the medical treatment group 27% of surviving patients had class I or II symptoms and 67% had class III or IV symptoms. In the cardiomyoplasty group left ventricular ejection fraction increased from 20% +/- 3% to 24.4% +/- 6.3% at 6 months (p < 0.05). In the heart transplantation group the left ventricular ejection fraction normalized, and the mean value of the left ventricular ejection fraction did not change in the medical treatment group. The need for endomyocardial biopsy and the incidence of rejection and infection were characteristics of the heart transplantation group.

CONCLUSIONS

In properly selected patients, cardiomyoplasty and heart transplantation seem to be associated with improvement in survival and functional class at mid-term follow-up. Heart transplantation was more effective than cardiomyoplasty for functional class improvement.