The efficacy, challenges, and facilitators of telemedicine in post-treatment cancer survivorship care: an overview of systematic reviews.

BACKGROUND: Telemedicine services have been increasingly used to facilitate post-treatment cancer survivorship care, including improving access; monitoring health status, health behaviors, and symptom management; enhancing information exchange; and mitigating the costs of care delivery, especially since the COVID-19 pandemic. To inform guidance for the use of telemedicine in the post-COVID era, the aim of this overview of systematic reviews (SRs) was to evaluate the efficacy of, and survivor engagement in, telemedicine interventions in the post-treatment survivorship phase, and to consider implementation barriers and facilitators. METHODS: PubMed, Cochrane CENTRAL, CINAHL, Embase, and Web of Science databases were searched. SRs that examined the use of telemedicine in the post-treatment phase of cancer survivorship, published between January 2010 and April 2021, were included. Efficacy data were synthesized narratively. Implementation barriers and facilitators were synthesized using the Consolidated Framework for Implementation Research. RESULTS: Twenty-nine SRs were included. A substantive body of evidence found telemedicine to benefit the management of psychosocial and physical effects, particularly for improving fatigue and cognitive function. There was a lack of evidence on the use of telemedicine in the prevention and surveillance for recurrences and new cancers as well as management of chronic medical conditions. This overview highlights a range of diverse barriers and facilitators at the patient, health service, and system levels. CONCLUSIONS: This review highlights the benefits of telemedicine in addressing psychosocial and physical effects, but not in other areas of post-treatment cancer survivorship care. This large review provides practical guidance for use of telemedicine in post-treatment survivorship care.

The potential therapeutic effects of creatine supplementation on body composition and muscle function in cancer.

Low muscle mass in individuals with cancer has a profound impact on quality of life and independence and is associated with greater treatment toxicity and poorer prognosis. Exercise interventions are regularly being investigated as a means to ameliorate treatment-related adverse effects, and nutritional/supplementation strategies to augment adaptations to exercise are highly valuable. Creatine (Cr) is a naturally-occurring substance in the human body that plays a critical role in energy provision during muscle contraction. Given the beneficial effects of Cr supplementation on lean body mass, strength, and physical function in a variety of clinical populations, there is therapeutic potential in individuals with cancer at heightened risk for muscle loss. Here, we provide an overview of Cr physiology, summarize the evidence on the use of Cr supplementation in various aging/clinical populations, explore mechanisms of action, and provide perspectives on the potential therapeutic role of Cr in the exercise oncology setting.

Mechanical basis of bone strength: influence of bone material, bone structure and muscle action.

This review summarises current understanding of how bone is sculpted through adaptive processes, designed to meet the mechanical challenges it faces in everyday life and athletic pursuits, serving as an update for clinicians, researchers and physical therapists. Bone's ability to resist fracture under the large muscle and locomotory forces it experiences during movement and in falls or collisions is dependent on its established mechanical properties, determined by bone's complex and multidimensional material and structural organisation. At all levels, bone is highly adaptive to habitual loading, regulating its structure according to components of its loading regime and mechanical environment, inclusive of strain magnitude, rate, frequency, distribution and deformation mode. Indeed, the greatest forces habitually applied to bone arise from muscular contractions, and the past two decades have seen substantial advances in our understanding of how these forces shape bone throughout life. Herein, we also highlight the limitations of in vivo methods to assess and understand bone collagen, and bone mineral at the material or tissue level. The inability to easily measure or closely regulate applied strain in humans is identified, limiting the translation of animal studies to human populations, and our exploration of how components of mechanical loading regimes influence mechanoadaptation.

Reorganization of filamentous actin and myosin-II in zebrafish eggs correlates temporally and spatially with cortical granule exocytosis.

The zebrafish egg provides a useful experimental system to study events of fertilization, including exocytosis. We show by differential interference contrast videomicroscopy that cortical granules are: (1) released nonsynchronously over the egg surface and (2) mobilized to the plasma membrane in two phases, depending upon vesicle size and location. Turbidometric assay measurements of the timing and extent of exocytosis revealed a steady release of small granules during the first 30 seconds of egg activation. This was followed by an explosive discharge of large granules, beginning at 30 seconds and continuing for 1-2 minutes. Stages of single granule exocytosis and subsequent remodeling of the egg surface were imaged by either real-time or time-lapse videomicroscopy as well as scanning electron microscopy. Cortical granule translocation and fusion with the plasma membrane were followed by the concurrent expansion of a fusion pore and release of granule contents. A dramatic rearrangement of the egg surface followed exocytosis. Cortical crypts (sites of evacuated granules) displayed a purse-string-like contraction, resulting in their gradual flattening and disappearance from the egg surface. We tested the hypothesis that subplasmalemmal filamentous (F-) actin acts as a physical barrier to secretion and is locally disassembled prior to granule release. Experimental results showed a reduction of rhodamine-phalloidin and antimyosin staining at putative sites of secretion, acceleration of the timing and extent of granule release in eggs pretreated with cytochalasin D, and dose-dependent inhibition of exocytosis in permeabilized eggs preincubated with phalloidin. An increase in assembled actin was detected by fluorometric assay during the period of exocytosis. Localization studies showed that F-actin and myosin-II codistributed with an inward-moving, membrane-delimited zone of cytoplasm that circumscribed cortical crypts during their transformation. Furthermore, cortical crypts displayed a distinct delay in transformation when incubated continuously with cytochalasin D following egg activation. We propose that closure of cortical crypts is driven by a contractile ring whose forces depend upon dynamic actin filaments and perhaps actomyosin interactions.

The cortical actin cytoskeleton of unactivated zebrafish eggs: spatial organization and distribution of filamentous actin, nonfilamentous actin, and myosin-II.

Actin and nonmuscle myosin heavy chain (myosin-II) have been identified and localized in the cortex of unfertilized zebrafish eggs using techniques of SDS-polyacrylamide gel electrophoresis, immunoblotting, and fluorescence microscopy. Whole egg mounts, egg fragments, cryosections, and cortical membrane patches probed with rhodamine phalloidin, fluorescent DNase-I, or anti-actin antibody showed the cortical cytoskeleton to contain two domains of actin: filamentous and nonfilamentous. Filamentous actin was restricted to microplicae and the cytoplasmic face of the plasma membrane where it was organized as an extensive meshwork of interconnecting filaments. The cortical cytoplasm deep to the plasma membrane contained cortical granules and sequestered actin in nonfilamentous form. The cytoplasmic surface (membrane?) of cortical granules displayed an enrichment of nonfilamentous actin. An antibody against human platelet myosin was used to detect myosin-II in whole mounts and egg fragments. Myosin-II colocalized with both filamentous and nonfilamentous actin domains of the cortical cytoskeleton. It was not determined if egg myosin was organized into filaments. Similar to nonfilamentous actin, myosin-II appeared to be concentrated over the surface of cortical granules where staining was in the form of patches and punctate foci. The identification of organized and interconnected domains of filamentous actin, nonfilamentous actin, and myosin-II provides insight into possible functions of these proteins before and after fertilization.

The sperm entry site during fertilization of the zebrafish egg: localization of actin.

The sperm entry site (SES) of zebrafish (Brachydanio rerio) eggs was studied before and during fertilization by fluorescence, scanning, and transmission electron microscopy. Rhodamine phalloidin (RhPh), used to detect polymerized filamentous actin, was localized to microvilli of the SES and to cytoplasm subjacent to the plasma membrane in the unfertilized egg. The distribution of RhPh staining at the SES correlated with the ultrastructural localization of a submembranous electrondense layer of cortical cytoplasm approximately 500 nm thick and containing 5- to 6-nm filaments. Actin, therefore, was organized at the SES as a tightly knit meshwork of filaments prior to fertilization. Contact between the fertilizing sperm and the filamentous actin network was observed by 15-20 sec postinsemination or just before the onset of fertilization cone formation. Growing fertilization cones of either artificially activated or inseminated eggs exhibited intense RhPh staining and substantial increase in thickness of the actin meshwork. Collectively, TEM and RhPh fluorescence images of inseminated eggs demonstrated that the submembranous actin became rearranged in fertilization cones to form a thickened meshwork around the sperm nucleus during incorporation. The results reported here suggest that activation of the egg triggers a dramatic polymerization of actin beneath the plasma membrane of the fertilization cone. Furthermore, the actin involved in sperm incorporation is sensitive to the action of cytochalasins.

An electron-microscope and freeze-fracture study of the egg cortex of Brachydanio rerio.

We have examined the cortex of the teleost (Brachydanio rerio) egg before and during exocytosis of cortical granules by scanning, transmission, and freeze-fracture electron microscopy. In the unactivated egg, the P-face of the plasma membrane exhibits a random distribution of intramembranous particles, showing a density of 959/micron2 and an average diameter of 8 nm. Particles over P- and E-faces of the membranes of cortical granules are substantially larger and display a significantly lower density. An anastomosing cortical endoplasmic reticulum forms close associations with both the plasma membrane of the egg and the membranes of cortical granules. Exocytosis begins with cortical granules pushing up beneath the plasma membrane to form dome-shaped swellings, coupled with an apparent clearing of particles from the site of contact between the apposed membranes. A depression in the particle-free plasma membrane appears to mark sites of fusion and pore formation between cortical granules and plasma membranes. Profiles of exocytotic vesicles undergo a predictable sequence of morphological change, but maintain their identity in the egg surface during this transformation. Coated vesicles form at sites of cortical granule breakdown. Differences in particle density between cortical granules and egg plasma membranes persist during transformation of the exocytotic profiles. This suggests that constituents of the 2 membrane domains remain segregated and do not intermix rapidly, lending support to the view that the process of membrane retrieval is selective (i.e., cortical granule membrane is removed).

Effects of cytochalasins B and D on the fertilization of zebrafish (Brachydanio) eggs.

The effects of selected concentrations of cytochalasins B (1-10 micrograms/ml; CB) and D (10, 50 micrograms/ml; CD) on the morphology and fertilization of zebra danio (Brachydanio) eggs were studied primarily with light and scanning electron microscopy. Eggs pretreated with either CB (10 micrograms/ml) or CD (10, 50 micrograms/ml) prepared in Fish Ringer's solution-0.5% DMSO showed a flattened shape, alterations in the form of surface microplicae and microvilli, and occasional spontaneous exocytosis of cortical granules. All eggs preincubated in either CB or CD were activated upon transfer to tap water, showing cortical granule exocytosis, elevation of the chorion, and formation of a fertilization cone. When eggs were pretreated for 5 minutes with 1-5 micrograms/ml CB or 10 micrograms/ml CD and inseminated, they incorporated the fertilizing sperm and typically developed to the two-cell stage. A single sperm cell attached to and fused with the sperm entry site microvilli but failed to enter the cytoplasm in eggs preincubated with 10 micrograms/ml CB. Eggs that were immersed continuously in either CB (10 micrograms/ml) or CD (50 micrograms/ml) 15 seconds after insemination also failed to incorporate the fertilizing sperm. Treatment of eggs after insemination with CD (10 micrograms/ml), however, did not prevent sperm cell incorporation or fertilization cone formation. Our drug data suggest the presence of actin-containing filaments in the danio egg before and following fertilization. These filaments appear to play a role in maintaining the shape of the egg cell and its surface specializations and in the incorporation of the fertilizing sperm. The fertilization cone appears to form independently of actin polymerization.

Ultrastructural localization of lysosomal enzymes in the egg cortex of Brachydanio.

The localization of acid phosphatase (E.C. 3.1.3.2), inorganic trimetaphosphatase (E.C. 3.6.1.2), and aryl sulfatase (E.C. 3.1.6.1) in the cortex of unactivated and activated eggs of Brachydanio was examined by ultrastructural cytochemistry. Using a lead capture method, activity for all three acid hydrolases was demonstrated in organelles of the cortex before and after egg activation. Acid phosphatase (AcPase) reaction product was consistently present in primary lysosomes, secondary lysosomes, multivesicular bodies, and yolk bodies. AcPase activity was absent from mitochondria, profiles of the endoplasmic reticulum, coated pits of exocytosed cortical granules, and coated vesicles. Although most cortical granules of the mature, unactivated egg were unreactive for this enzyme, a few showed AcPase reaction product. It is not clear whether the AcPase-positive granules might be an immature form of cortical granules or a subpopulation of these organelles with lysosomal properties. Most cisternae of the Golgi apparatus did not stain for AcPase; however, reaction product was occasionally localized in a single cisterna as well as several small vesicles at the inner face of the Golgi. The intensity of the reaction product and the pattern of distribution of trimetaphosphatase (Tm-Pase) activity was very similar to that of AcPase. However, TmPase was never observed in cortical granules. Cortices of unactivated and activated eggs showed less overall aryl sulfatase (ArSase) activity when compared with AcPase and TmPase. The presence of ArSase reaction product in lysosomes and multivesicular bodies confirmed the acid hydrolytic nature of these organelles. AcPase and TmPase, and to a lesser extent ArSase, are adequate markers of a cortical lysosomal system in the danio egg.(ABSTRACT TRUNCATED AT 250 WORDS)

Scanning electron microscope studies of sperm incorporation into the zebrafish (Brachydanio) egg.

Morphological studies on the gametes and entry of the spermatozoan into the egg of the zebra danio, Brachydanio rerio, were conducted primarily with scanning electron microscopy. The spermatozoan showed a spherical head, which lacked an acrosome, a midpiece containing several mitochondria, and a flagellum. Observations of the unfertilized egg confirmed and extended prior studies showing a distinct cluster of microvilli on the plasma membrane, identified as the sperm entry site, beneath the inner micropylar aperture (Hart and Donovan, '83). The fertilizing spermatozoan attached to the sperm entry site within 5 seconds of the mixing of a gamete suspension. Binding to the egg microvilli appeared restricted to the equatorial surface of the spermatozoan. Fusion between the plasma membranes of the interacting gametes was followed by the formation of a distinct, nipple-shaped fertilization cone. The sperm head was partially incorporated into the fertilization cone cytoplasm by 60 seconds postinsemination. The incorporation of the entire sperm head, midpiece, and a portion of the flagellum occurred between 1 and 2 minutes. During this time, the fertilization cone shortened and was transformed into a massive, blister-like cytoplasmic swelling. Concurrently, upward movements of the ooplasm resulted in the gradual disappearance of the original depression in the egg surface containing the sperm entry site. The second polar body, fully developed by 10 minutes postinsemination, formed approximately 10-15 microns from the site of sperm penetration. Development of the fertilization cone, formation of the second polar body and exocytosis of cortical granules at the sperm entry site readily occurred in parthenogenetically activated eggs, indicating that these surface rearrangements do not require sperm binding and/or fusion.

Cortical granule exocytosis is coupled with membrane retrieval in the egg of Brachydanio.

Activation of the teleost (Brachydanio) fish egg includes the exocytosis of cortical granules, the construction of a mosaic surface consisting of the unfertilized egg plasma membrane and the limiting membranes of the cortical granules, and the appearance of coated and smooth vesicles in the cytoplasm (Donovan and Hart, '82). Unfertilized and activated eggs were incubated in selected extracellular tracers to (1) determine experimentally if cortical granule exocytosis was coupled with the endocytosis of membrane during the cortical reaction, and (2) establish the intracellular pathway(s) by which internalized vesicles were processed. Unfertilized eggs incubated in dechlorinated tap water or Fish Ringer's solution containing either horseradish peroxidase (HRP; 10 mg/ml), native ferritin (12.5 mg/ml), or cationized ferritin (12.5 mg/ml) were activated as judged by cortical granule breakdown and elevation of the chorion. Cells treated with HRP and native ferritin exhibited a delay in cortical granule exocytosis when compared with water-activated eggs lacking the tracer. Each tracer was internalized through the formation of a coated vesicle from a coated pit. Since coated pits appeared to be topographically restricted to the perigranular membrane domain of the mosaic egg surface, their labeling, particularly with cationized ferritin, strongly suggested that the retrieved membrane was of cortical granule origin. Cationized ferritin and concanavalin A (Con A) coupled with either hemocyanin or ferritin labeled the surface of the unactivated egg and both domains of the mosaic egg surface. Transformation of the deep evacuated cortical granule crypt into later profiles of exocytosis was accompanied by increased Con A binding. Within activated egg cortices, HRP reaction product, native ferritin, and cationized ferritin were routinely localized in smooth vesicles, multivesicular bodies, and autophagic vacuoles. Occasionally, each tracer was found in small coated vesicles adjacent to the Golgi and within Golgi cisternae. The intracellular distribution of HRP, native ferritin, and cationized ferritin suggests that internalized membrane is primarily processed by organelles of the lysosomal compartment. A second and less significant pathway is the Golgi complex.

The structure of the chorion and associated surface filaments in Oryzias--evidence for the presence of extracellular tubules.

The structure of the chorion with its associated surface filaments has been examined in Oryzias latipes using several techniques, including scanning and transmission electron microscopy, enzymatic digestion, and sodium dodecylsulfate-polyacrylamide gel electrophoresis. The chorion of the recently fertilized egg was found to be organized into three zones: an outer, fuzzy electron-lucent zone that was continuous over the surface of filaments, a middle, homogeneous electron-dense zone, and an inner zone of ten to 12 horizontal, fibrous lamellae. Two topographically distinct types of filaments were found on the chorionic surface: nonattaching and attaching. Nonattaching filaments showed a regular spatial distribution over the chorion with an interfilament distance of about 60-70 microns. Attaching filaments originated from a localized portion of the chorion and united with those of neighboring eggs to anchor the egg cluster to the gonoduct of the female. Both nonattaching and attaching filaments were morphologically regionalized into basal and distal segments. Internally, nonattaching and attaching filaments were constructed of unbranched, packed tubules with an average outside diameter of approximately 19.5 and 18.8 nm, respectively. Using the attaching filament for further study, it was determined by rotational analysis (Markham et al., '63) that the wall of each tubule was a cylinder composed of 14 globular subunits. Two structural types of attaching filaments were identified. The type I attaching filament was similar in internal organization to the nonattaching filament and consisted of only tubules. The type II attaching filament, however, showed a highly osmiophilic, electron-dense bar surrounded by packed tubules. Tubules of attaching filaments of the adult were resistant to the action of Triton X-100 and colchicine, but sensitive to a 0.1% protease solution. However, colchicine-treated ovary tissue showed an absence and pattern of disorganization of tubules at the periphery of developing filaments. Solubilized attaching filament samples electrophoresed on 7.5% polyacrylamide-SDS gels were resolved into a pair of Coomassie-blue-positive bands that comigrated with purified porcine brain tubulin. The apparent molecular weight of the attaching filament polypeptide was determined to be approximately 55,000 daltons. These data suggest that the extracellular, tubular components of attaching filaments (as well as nonattaching filaments) are proteinaceous and show properties similar to those of cytoplasmic microtubules. Tubular precursor material was electron-dense and appeared to originate in the cisternae of the rough endoplasmic reticulum of ovarian foll

Uptake of ferritin by the mosaic egg surface of Brachydanio.

The internalization of membrane from the mosaic egg surface of the zebra fish, Brachydanio, was investigated using anionic ferritin and transmission electron microscopy. The cortical cytoplasm of the 5-min activated egg showed numerous membrane-bound vesicles not found in the unactivated egg cortex. Two types of vesicles were identified: uncoated (smooth) and coated. Coated vesicles measured about 0.7 to 0.9 micrometer in diameter. Coated pits, considered to be precursors to the formation of coated vesicles, were frequently observed at the base of membrane-lined cortical granule crypts. Anionic ferritin was localized over coated pits and in both smooth and coated vesicles. The absence of any morphological evidence of a surface origin for smooth vesicles suggested these ferritin-labeled organelles might be formed by coated vesicle fusion. Our results indicate that the plasma membrane redundancy created by the exocytosis of cortical granules in Brachydanio appears to be resolved in part by the internalization of membrane through endocytosis.

Developmental expression of glucose and triose phosphate isomerase genes in teleost fishes (brachydanio).

The ontogeny of glucosephosphate isomerase (GPI; E.C. 5.3.1.9) and triosephosphate isomerase (TPI; E.C. 5.3.1.1) isozymes in Brachydanio rerio, (zebra danio), B. albolineatus (pearl danio) and hybrids formed by their reciprocal crosses were examined by electrophoretic and spectrophotometric methods. The two species showed virtually identical adult, tissue-specific distributions and developmental progressions for both GPI and TPI isozymes. The Gpi-A and Tpi-B loci were expressed in all tissues studied. The Gpi-B locus was predominantly expressed in skeletal muscle and the Tpi-A locus in eye, brain and ovary. The GPI-A2, TPI-A2, TPI-AB and TPI-B2 isozymes were continuously expressed from fertilization through 5 days postfertilization. The GPI-B2 isozyme initially appeared at 35 hours postfertilization, temporally correlating with the early differentiation of trunk somite myoblasts. Spectrophotometric analysis of total GPI showed fluctuations in activity through 48 hours, followed by a steady increase through 4 days postfertilization. Total TPI showed increased activity by the end of gastrulation and a sharp rise in activity beginning at 25 hours postfertilization. Embryos of reciprocal hybrids between B. rerio and B. albolineatus showed that isozymes derived from the activation of the paternal Tpi-B, Gpi-A and Tpi-A alleles were initially detected at 20, 25, and 48 hours following fertilization, respectively. The maternal and paternal isozymes of the Gpi-B locus were synchronously expressed at 35 hours postfertilization. The pattern of GPI-B2 expression in hybrids followed a pattern similar to that in intraspecific crosses. Exposure of B. rerio embryos to pulses of actinomycin D at various stages prior to 35 hours postfertilization showed that messenger RNA encoding the GPI-B2 isozyme was first transcribed over a 14-hour interval initiated during mid-gastrulation. Translation of the GPI-B2 message occurred during a 13-hour period immediately preceding the embryonic expression of the GPI-B2 isozyme. Our studies with Brachydanio indicate that several gene loci are activated at gastrulation and transcribe messenger RNA molecules coding for histospecific isozymes associated with later stages of organogenesis.

Esterase isozyme patterns in developing embryos of Brachydanio rerio (zebra danio), Brachydanio abolineatus (pearl danio), and their hybrids.

The ontogeny of esterase isozymes in Brachydanio rerio (zebra danio), Brachydanio albolineatus (pearl danio), and hybrids formed by their reciprocal crosses was investigated using polyacrylamide disc electrophoresis. Seven esterase isozymes were identified in each species from the unfertilized egg stage to nine days posthatch. Electrophoretic analysis of qualitative changes in enzyme pattern indicated that some esterases were present at all stages of development while other esterases abruptly appeared at a specific stage of morphological differentiation. The esterases of both species were classified on the basis differential substrate and inhibitor specificities. In developing hybrids formed by B. rerio eggs inseminated with B. albolineatus sperm, the maternal isozyme pattern persisted until Stage 17 (gastrulation). Embryonic extracts from Stage 17 onward showed a slow-moving, DFP-sensitive carboxylesterase of paternal origin. In developing hybrids formed by B. albolineatus eggs inseminated with B. rerio sperm, a paternal contribution to the esterase pattern was probably present by the end of gastrulation; esterase activity of distinctively paternal origin was present by Stage 22 (retinal pigmentation) The maternal contribution to the total esterase profile appeared to remain high through hatching. Additional evidence for gene activity at gastrulation was obtained in experiments utilizing actinomycin-D and cycloheximide. Results of exposing embryos of B. rerio to 15 mug/ml of actinomycin-D indicated that transcription of the template RNA coding for cholinesterase occurred during gastrulation or some 20-30 hours prior to the appearance of the isozyme at Stage 22. This template RNA was translated sometime during that 10-hour interval immediately preceding Stage 22.

Teratologic effects of LSD in explanted early chick embryos.

Chick embryos were explanted at stage; 4-7 and cultured for 20 h with or without LSD. At any stage 10 mug/ml LSD or higher caused abnormalities in axial structures, particularly somites, in over 50% of the embryos. LSD had no apparent effect on morphogenesis of the heart, but significantly lowered the pulse rate. Cellular degeneration occurred in severely affected structures, but LSD at embryotoxic doses caused alterations in neither cell morphology nor mitotic activity. The effects of LSD were not permanent, i.e., the embryos retained the ability to undergo normal morphogenesis when, after 4-5 h of treatment with 10 mug/ml LSD, they were subcultured on plain nutrient medium.