Effects of a new cardiomyoplasty technique on cardiac function

OBJECTIVE: The current cardiomyoplasty technique was modified to maintain the resting tension of the latissimus dorsi muscle and to prevent lateral movement of the heart during muscle stimulation. The aim of this study is to compare the short term hemodynamic effects of the new cardiomyoplasty wrap (W1) with those of the clinically applied cardiomyoplasty wrap (W2). Preliminary indications of the long-term hemodynamic effects of W1 are presented. METHODS: In three acute experiments in sheep mean central venous pressure (MCVP), mean arterial pressure (MAP), mean cardiac output (MCOP), mean left ventricular systolic pressure (MLVSP), and mean left ventricular diastolic pressure (MLVDP) were measured for 30s before and five minutes after applying each procedure with and without stimulation of the muscle graft. The same parameters were also recorded 5min after removing each muscle wrap. Hemodynamic changes associated with unstimulated muscle wraps were compared to the baseline data. Hemodynamic effects of muscle stimulation were determined by comparing the assisted to the preceding unassisted cardiac cycle. The long-term effects of W1 on the hemodynamics of another three sheep were studied at 6-12months after the operation. The viability of the muscles used in the chronic experiments were evaluated by morphometric analysis. RESULTS: Unstimulated W2 significantly increased mean central venous pressure and reduced mean cardiac output. It also increased mean left ventricular diastolic pressure and reduced peak negative dP/dt. Unstimulated W1 had no deleterious effect on mean central venous pressure, mean left ventricular diastolic pressure or peak -dP/dt, but it also reduced mean cardiac output and increased mean left atrial pressure (MLAP). Synchronised muscle stimulation, in both techniques, augmented the mean arterial pressure, mean cardiac output and mean left ventricular systolic pressure. In W2, however, myostimulation was also associated with a significant increase of the mean left ventricular diastolic pressure. In two long-term experiments significant hemodynamic assistance was observed at 6months and at 1yr after W1. In those sheep 68% of the cross-sectional area of the muscle was well preserved. CONCLUSIONS: Unstimulated cardiomyoplasty wraps acutely impair left ventricular function in sheep. The new technique, however, may offer significant long-term hemodynamic assistance and adequate preservation of the structural and functional integrity of the muscle flap for up to 1yr.     

Annexin V for flow cytometric detection of phosphatidylserine expression on B cells undergoing apoptosis

Apoptosis, or programmed cell death, is a general mechanism for removal of unwanted cells from the immune system. It is characterized by chromatin condensation, a reduction in cell volume, and endonuclease cleavage of DNA into oligonucleosomal length fragments. Apoptosis is also accompanied by a loss of membrane phospholipid asymmetry, resulting in the exposure of phosphatidylserine at the surface of the cell. Expression of phosphatidylserine at the cell surface plays an important role in the recognition and removal of apoptotic cells by macrophages. Here we describe a new method for the detection of apoptotic cells by flow cytometry, using the binding of fluorescein isothiocyanate-labeled annexin V to phosphatidylserine. When Burkitt lymphoma cell lines and freshly isolated germinal center B cells are cultured under apoptosis inducing conditions, all cells showing chromatin condensation strongly stain with annexin V, whereas normal cells are annexin V negative. Moreover, DNA fragmentation is only found in the annexin V-positive cells. The nonvital dye ethidium bromide was found to stain a subpopulation of the annexin V-positive apoptotic cells, increasing with time. Our results indicate that the phase in apoptosis that is characterized by chromatin condensation coincides with phosphatidylserine exposure. Importantly, it precedes membrane damage that might lead to release from the cells of enzymes that are harmful to the surrounding tissues. Annexin V may prove important in further unravelling the regulation of apoptosis.     

Natural bioburden levels detected on rigid lumened medical devices before and after cleaning

Controversy exists concerning the degree of microbial contamination associated with the us of rigid lumened medical devices, the efficacy of standard cleaning techniques used to remove pathogenic microorganisms from lumen channels, and whether patients are placed at risk of cross infection because of microbial contamination. In this study the level and types of microorganisms found on rigid lumened medical devices before and after cleaning in a hospital environment were investigated. The bioburden level after clinical use was found to be relatively low, ranging from 10¹ to 10⁴ colony forming units (CFU) per device. After the instruments were cleaned, none of the devices studied contained bioburden levels greater than 10⁴ CFU and 83% had bioburden levels less than or equal to 10² CFU. The bioburden present before cleaning was comprised of organisms derived from the handling of the device, from the hospital environment, and from the patient. The bioburden present after cleaning was comprised of organisms typically derived from the handling of the device and from the hospital environment. The level of bioburden per device was also related to the anatomic site where the device was used, with lower numbers of organisms found on devices exposed to sterile body sites and the respiratory tract.     

Exploiting PI3K/mTOR signaling to accelerate epithelial wound healing

The molecular circuitries controlling the process of skin wound healing have gained new significant insights in recent years. This knowledge is built on landmark studies on skin embryogenesis, maturation, and differentiation. Furthermore, the identification, characterization, and elucidation of the biological roles of adult skin epithelial stem cells and their influence in tissue homeostasis have provided the foundation for the overall understanding of the process of skin wound healing and tissue repair. Among numerous signaling pathways associated with epithelial functions, the PI3K/Akt/mTOR signaling route has gained substantial attention with the generation of animal models capable of dissecting individual components of the pathway, thereby providing a novel insight into the molecular framework underlying skin homeostasis and tissue regeneration. In this review, we focus on recent findings regarding the mechanisms involved in wound healing associated with the upregulation of the activity of the PI3K/Akt/mTOR circuitry. This review highlights critical findings on the molecular mechanisms controlling the activation of mTOR, a downstream component of the PI3K–PTEN pathway, which is directly involved in epithelial migration and proliferation. We discuss how this emerging information can be exploited for the development of novel pharmacological intervention strategies to accelerate the healing of critical size wounds.     

Protective effects of Mentha piperita Linn on benzo[a]pyrene-induced lung carcinogenicity and mutagenicity in Swiss albino mice

The Editor-in-Chief has retracted the published paper "ProtectiveEffects of     

The contribution of primary care practitioners to interventions reducing loneliness and social isolation in older people—An integrative review

Background

Social connection is a fundamental human need. Its absence can lead to loneliness and social isolation, adversely impacting health and well-being. Given their regular contact and trusted relationships with older people, practitioners delivering community-based primary care are well-positioned to address this issue. However, their contribution to addressing loneliness and social isolation is unclear.

Aim

This integrative review explores the contribution of the primary care workforce to interventions aimed at reducing loneliness and social isolation in community-dwelling older people.

Method

Using an integrative review method, Scopus, Web of Science, CINAHL and PubMed were searched for original research published between 2000 and 2022. Fourteen papers reporting 13 primary studies were appraised for methodological quality and included in the review. Data were extracted into a summary table and analysed using thematic analysis.

Results

Included studies came from over six countries. Internationally, primary care services have diverse structures, funding and workforces influencing their response to loneliness and social isolation. All but one intervention was multi-component, with ten studies including a group-based activity and three providing primarily individual-level activities. Only six studies reported reductions in loneliness following the intervention. Three themes were identified: characteristics of interventions; implementation context, barriers and facilitators; and differing contributions of primary care practitioners in addressing loneliness and social isolation of older people.

Conclusion

There is increasing demand and scope for primary care practitioners to assist lonely and socially isolated older people. It is important to understand how to equip and incentivise these practitioners to routinely identify, assess and respond to lonely and socially isolated older people despite varying implementation contexts. There is a need for further research that explores how the primary care team can be better utilised to deliver effective interventions that reduce the health impacts of loneliness and social isolation.